Determinants of discordance in patients' and physicians' rating of rheumatoid arthritis disease activity

Objective To assess the determinants of patients' (PTGL) and physicians' (MDGL) global assessment of rheumatoid arthritis (RA) activity and factors associated with discordance among them. Methods. A total of 7,028 patients in the Quantitative Standard Monitoring of Patients with RA study had PTGL and MDGL assessed at the same clinic visit on a 0-10-cm visual analog scale (VAS). Three patient groups were defined: concordant rating group (PTGL and MDGL within >= 2 cm), higher patient rating group (PTGL exceeding MDGL by > 2 cm), and lower patient rating group (PTGL less than MDGL by > 2 cm). Multivariable regression analysis was used to identify determinants of PTGL and MDGL and their discordance. Results. The mean +/- SD VAS scores for PTGL and MDGL were 4.01 +/- 2.70 and 2.91 +/- 2.37, respectively. Pain was overwhelmingly the single most important determinant of PTGL, followed by fatigue. In contrast, MDGL was most influenced by swollen joint count (SJC), followed by erythrocyte sedimentation rate (ESR) and tender joint count (TJC). A total of 4,454 (63.4%), 2,106 (30%), and 468 (6.6%) patients were in the concordant, higher, and lower patient rating groups, respectively. Odds of higher patient rating increased with higher pain, fatigue, psychological distress, age, and morning stiffness, and decreased with higher SJC, TJC, and ESR. Lower patient rating odds increased with higher SJC, TJC, and ESR, and decreased with lower fatigue levels. Conclusion. Nearly 36% of patients had discordance in RA activity assessment from their physicians. Sensitivity to the "disease experience" of patients, particularly pain and fatigue, is warranted for effective care of RA.

On the impact of disproportional samples in credit scoring models: An application to a Brazilian bank data

Statistical methods have been widely employed to assess the capabilities of credit scoring classification models in order to reduce the risk of wrong decisions when granting credit facilities to clients. The predictive quality of a classification model can be evaluated based on measures such as sensitivity, specificity, predictive values, accuracy, correlation coefficients and information theoretical measures, such as relative entropy and mutual information. In this paper we analyze the performance of a naive logistic regression model (Hosmer & Lemeshow, 1989) and a logistic regression with state-dependent sample selection model (Cramer, 2004) applied to simulated data. Also, as a case study, the methodology is illustrated on a data set extracted from a Brazilian bank portfolio. Our simulation results so far revealed that there is no statistically significant difference in terms of predictive capacity between the naive logistic regression models and the logistic regression with state-dependent sample selection models. However, there is strong difference between the distributions of the estimated default probabilities from these two statistical modeling techniques, with the naive logistic regression models always underestimating such probabilities, particularly in the presence of balanced samples. (C) 2012 Elsevier Ltd. All rights reserved.

Comparação dos instrumentos Childhood Autism Rating Scale e Autism Behavior Checklist na identificação e caracterização de indivíduos com distúrbios do espectro autístico

OBJETIVO: Comparar as respostas dos instrumentos Childhood Autism Rating Scale e Autism Behavior Checklist na identificação e caracterização de indivíduos com Distúrbios do Espectro Autístico. MÉTODOS: Participaram 28 indivíduos que estavam em atendimento fonoaudiológico e possuíam diagnósticos inseridos no Espectro do Autismo. Todos foram avaliados por meio dos instrumentos Autism Behavior Checklist e Childhood Autism Rating Scale a partir de informações obtidas, respectivamente, com pais e terapeutas. Os dados foram analisados estatisticamente em relação à concordância das respostas obtidas. Foram considerados concordantes os resultados de alta ou moderada probabilidade para autismo no Autism Behavior Checklist e com autismo leve-moderado ou grave na Childhood Autism Rating Scale, e respostas de baixa probabilidade no Autism Behavior Checklist e sem autismo na Childhood Autism Rating Scale. RESULTADOS: Houve concordância na maior parte das respostas obtidas. Casos em que houve discordância entre os resultados obtidos a partir dos protocolos corroboram dados da literatura, evidenciando que os instrumentos podem não ser suficientes, quando aplicados isoladamente para a definição do diagnóstico. CONCLUSÃO: Enquanto a Childhood Autism Rating Scale pode não diagnosticar crianças efetivamente autistas, o Autism Behavior Checklist pode incluir como autistas, crianças com outros distúrbios. Portanto, recomenda-se o uso complementar dos dois instrumentos.

Assessing speaking skills in English: an approach to test and rating scale design in a university context

Programa de Doctorado: Formación del Profesorado

Mortgage securitization and its credit risk control

This dissertation concentrate on the mortgage securitization and its credit risk, which are criticized as the main causes of the financial crisis. From the point of the veiw of mortgage's evolution, the nature, structure and function of mortgage has been radically changed, yet the mortgage law did not give appropriate response to this market change. Meanwhile, the U.S legilslations facilitating the mortgage securitization also have rotten the legal foundations for mortgage market self-regulation and sustained development. In contrast, the EU covered bond system has kept financial stability for 200 years' time, and their statutory approach has been proved to be able to control the credit risk and incentive problems very well, in combination of market self-regulation and public regulation. So the future reform should be directed to strengthen the market's capacity of self-regulation and improve the public regulation. For the development of mortgage securitization in China, it is suggested to introduce the EU covered bond system for the reason of the equilibrium between funding efficiency and financial stability.

Modelli matematici applicati alla probabilità di default nei sistemi di rating.

L'obiettivo del seguente lavoro è determinare attraverso l'uso di procedure statistico-econometriche, in particolare del metodo ECM, le previsioni per i tassi di default nel triennio 2013-2015, partendo dalle serie storiche di questi ultimi e da quelle macroeconomiche.

Business process reengineering: soluzioni ingegneristiche in ottica di re-layout, riorganizzazione del processo "service" ed attività di vendor rating in HSD S.p.A.

L'attività svolta in HSD S.p.A. si è concentrata sulle seguenti tematiche: progettazione di un nuovo layout con annessa pianificazione delle attività necessarie e valutazione economica dell'investimento, audit focalizzato ad individuare le criticità legate al processo di logistica inversa e proporne soluzioni migliorative ed infine implementazione di un sistema di controllo specifico e comparato dei fornitori.

Il trattamento ortodontico nei bambini con particolari necessità sanitarie (SHCN): una valutazione della durata e del risultato clinico utilizzando l'indice PAR (Peer Assessment Rating), la componente DHC (Dental Health Component) e la componente AC (Aesthetic Component) dell'indice IOTN (Orthodontic Treatment Need Index)

Obbiettivo: Valutazione delle eventuali differenze nel trattamento ortodontico di un gruppo di bambini con particolari necessità sanitarie (SHCN) rispetto ad un gruppo di bambini non diagnosticati con SHCN. Materiali e Metodi: Il gruppo campione (SHCN) è costituito da 50 bambini con SHCN. Il gruppo di controllo (NO SHCN) è costituito da 50 bambini non diagnosticati con SHCN pienamente corrispondenti per età, genere e tipo di apparecchio ortodontico utilizzato con i pazienti del gruppo di studio. I dati riguardanti i gruppi SHCN e NO SHCN sono stati analizzati in modo retrospettivo, valutando: - il punteggio pre- e post-trattamento e la riduzione finale dei valori dell'indice PAR (Peer Assessment Rating), della componente DHC (Dental Health Component) e della componente AC (Aesthetic Component) dell'indice IOTN (Orthodontic Treatment Need Index), - il numero di appuntamenti, - il numero di sedute semplici e complesse, - la durata complessiva del trattamento, - l'età all’inizio ed alla fine della terapia. Risultati: Non sono state rilevate differenze statisticamente significative tra i due gruppi per quanto concerne il numero di appuntamenti, la durata complessiva del trattamento, l'età all’inizio ed alla fine della terapia ortodontica (valori del p-value:0.682, 0.458, 0.535, 0.675). Sono state rilevate differenze statisticamente significative tra i due gruppi per quanto riguarda i punteggi dell’indice PAR, delle componenti DHC e AC dello IOTN pre- e post-trattamento, il numero di sedute semplici e complesse (valori del p-value:0.030, 0.000, 0.020, 0.023, 0.000, 0.000, 0.043, 0.037). Per quanto concerne la riduzione finale del valore dell’indice PAR, della componente DHC e di quella AC dello IOTN non sono state riscontrate differenze statisticamente significative tra i due gruppi (valori del p-value:0.060, 0.765, 0.825). Conclusioni: Lo studio incoraggia gli ortodontisti a trattare i bambini con SHCN nell'obiettivo di migliorarne la qualità di vita, pur evidenziando la necessità di un maggior numero di sedute complesse.

Credit-Default-Swaps and the 2008 Financial Crisis: An Inquiry into the Underlying Legal Origins and the European Union’s Regulatory Reforms

After the 2008 financial crisis, the financial innovation product Credit-Default-Swap (CDS) was widely blamed as the main cause of this crisis. CDS is one type of over-the-counter (OTC) traded derivatives. Before the crisis, the trading of CDS was very popular among the financial institutions. But meanwhile, excessive speculative CDSs transactions in a legal environment of scant regulation accumulated huge risks in the financial system. This dissertation is divided into three parts. In Part I, we discussed the primers of the CDSs and its market development, then we analyzed in detail the roles CDSs had played in this crisis based on economic studies. It is advanced that CDSs not just promoted the eruption of the crisis in 2007 but also exacerbated it in 2008. In part II, we asked ourselves what are the legal origins of this crisis in relation with CDSs, as we believe that financial instruments could only function, positive or negative, under certain legal institutional environment. After an in-depth inquiry, we observed that at least three traditional legal doctrines were eroded or circumvented by OTC derivatives. It is argued that the malfunction of these doctrines, on the one hand, facilitated the proliferation of speculative CDSs transactions; on the other hand, eroded the original risk-control legal mechanism. Therefore, the 2008 crisis could escalate rapidly into a global financial tsunami, which was out of control of the regulators. In Part III, we focused on the European Union’s regulatory reform towards the OTC derivatives market. In specific, EU introduced mandatory central counterparty clearing obligation for qualified OTC derivatives, and requires that all OTC derivatives shall be reported to a trade repository. It is observable that EU’s approach in re-regulating the derivatives market is different with the traditional administrative regulation, but aiming at constructing a new market infrastructure for OTC derivatives.

A new yardstick for rating dental arch relationship in patients with complete bilateral cleft lip and palate

Objective: To develop yardsticks for assessment of dental arch relationship in young individuals with repaired complete bilateral cleft lip and palate appropriate to different stages of dental development. Participants: Eleven cleft team orthodontists from five countries worked on the projects for 4 days. A total of 776 sets of standardized plaster models from 411 patients with operated complete bilateral cleft lip and palate were available for the exercise. Statistics: The interexaminer reliability was calculated using weighted kappa statistics. Results: The interrater weighted kappa scores were between .74 and .92, which is in the "good" to "very good" categories. Conclusions: Three bilateral cleft lip and palate yardsticks for different developmental stages of the dentition were made: one for the deciduous dentition (6-year-olds' yardstick), one for early mixed dentition (9-year-olds' yardstick), and one for early permanent dentition (12-year-olds' yardstick).

Spatio-temporal credit assignment in population learning

Learning by reinforcement is important in shaping animal behavior, and in particular in behavioral decision making. Such decision making is likely to involve the integration of many synaptic events in space and time. However, using a single reinforcement signal to modulate synaptic plasticity, as suggested in classical reinforcement learning algorithms, a twofold problem arises. Different synapses will have contributed differently to the behavioral decision, and even for one and the same synapse, releases at different times may have had different effects. Here we present a plasticity rule which solves this spatio-temporal credit assignment problem in a population of spiking neurons. The learning rule is spike-time dependent and maximizes the expected reward by following its stochastic gradient. Synaptic plasticity is modulated not only by the reward, but also by a population feedback signal. While this additional signal solves the spatial component of the problem, the temporal one is solved by means of synaptic eligibility traces. In contrast to temporal difference (TD) based approaches to reinforcement learning, our rule is explicit with regard to the assumed biophysical mechanisms. Neurotransmitter concentrations determine plasticity and learning occurs fully online. Further, it works even if the task to be learned is non-Markovian, i.e. when reinforcement is not determined by the current state of the system but may also depend on past events. The performance of the model is assessed by studying three non-Markovian tasks. In the first task, the reward is delayed beyond the last action with non-related stimuli and actions appearing in between. The second task involves an action sequence which is itself extended in time and reward is only delivered at the last action, as it is the case in any type of board-game. The third task is the inspection game that has been studied in neuroeconomics, where an inspector tries to prevent a worker from shirking. Applying our algorithm to this game yields a learning behavior which is consistent with behavioral data from humans and monkeys, revealing themselves properties of a mixed Nash equilibrium. The examples show that our neuronal implementation of reward based learning copes with delayed and stochastic reward delivery, and also with the learning of mixed strategies in two-opponent games.

Spatio-temporal credit assignment in population learning

Learning by reinforcement is important in shaping animal behavior. But behavioral decision making is likely to involve the integration of many synaptic events in space and time. So in using a single reinforcement signal to modulate synaptic plasticity a twofold problem arises. Different synapses will have contributed differently to the behavioral decision and, even for one and the same synapse, releases at different times may have had different effects. Here we present a plasticity rule which solves this spatio-temporal credit assignment problem in a population of spiking neurons. The learning rule is spike time dependent and maximizes the expected reward by following its stochastic gradient. Synaptic plasticity is modulated not only by the reward but by a population feedback signal as well. While this additional signal solves the spatial component of the problem, the temporal one is solved by means of synaptic eligibility traces. In contrast to temporal difference based approaches to reinforcement learning, our rule is explicit with regard to the assumed biophysical mechanisms. Neurotransmitter concentrations determine plasticity and learning occurs fully online. Further, it works even if the task to be learned is non-Markovian, i.e. when reinforcement is not determined by the current state of the system but may also depend on past events. The performance of the model is assessed by studying three non-Markovian tasks. In the first task the reward is delayed beyond the last action with non-related stimuli and actions appearing in between. The second one involves an action sequence which is itself extended in time and reward is only delivered at the last action, as is the case in any type of board-game. The third is the inspection game that has been studied in neuroeconomics. It only has a mixed Nash equilibrium and exemplifies that the model also copes with stochastic reward delivery and the learning of mixed strategies.

Spatio-temporal credit assignment in population learning

We present a model for plasticity induction in reinforcement learning which is based on a cascade of synaptic memory traces. In the cascade of these so called eligibility traces presynaptic input is first corre lated with postsynaptic events, next with the behavioral decisions and finally with the external reinforcement. A population of leaky integrate and fire neurons endowed with this plasticity scheme is studied by simulation on different tasks. For operant co nditioning with delayed reinforcement, learning succeeds even when the delay is so large that the delivered reward reflects the appropriateness, not of the immediately preceeding response, but of a decision made earlier on in the stimulus - decision sequence . So the proposed model does not rely on the temporal contiguity between decision and pertinent reward and thus provides a viable means of addressing the temporal credit assignment problem. In the same task, learning speeds up with increasing population si ze, showing that the plasticity cascade simultaneously addresses the spatial problem of assigning credit to the different population neurons. Simulations on other task such as sequential decision making serve to highlight the robustness of the proposed sch eme and, further, contrast its performance to that of temporal difference based approaches to reinforcement learning.