Yield Curve Dynamics: Regional Common Factor Model

In this paper, we focus on thorough yield curve modelling. We build on extended classical Nelson-Siegel model, which we further develop to accommodate unobserved regional common factors. We centre our discussion on Central European currencies’ yield curves: CZK, HUF, PLN and SKK. We propose a model to capture regional dynamics purely based on state space formulation. The contribution of this paper is twofold: we examine regional yield curve dynamics and we quantify regional interdependencies amongst considered currencies’ yield curves. We conclude that the CZK yield curve possesses its own dynamics corresponding to country specific features, whereas other currencies’ yield curves are strongly influenced by the regional level, the regional slope factor or both.Dynamic Factor Model, Kalman Filter, Nelson-Siegel, State Space, Regional Yield Curve, Principal Component Analysis

Level of vascular ligation and association with oncological expediency in sigmoid and rectal cancer

Introduction: The techniques and oncology feasibility of high vascular ligation of the inferior mesenteric artery along with their varieties – low tie (LT) and high tie (HT) techniques in left-sided colon and rectal cancer, were described more than 100 years ago by Miles and Moynihan. However, the relationship between the level of vascular ligation and the microperfusion of the proximal anastomosis segment, on the one hand, and the volume and quality of lymphatic dissection, on the other, are the subject of numerous clinical trials and discussions. The vegetative nerve spare in the different approaches is also included in a consideration. Despite the well-established modern standardization in conventional and laparoscopic left colon and rectal cancer surgery, some surgeons still do ligation at the a. rectalis superior level in rectal cancer, which contradicts modern oncology principles.Materials and Methods: Prospective non-randomized comparative cohort study of patients from the Department of Surgery in Alexandrovska University Hospital with cancer of the sigmoid colon or rectum in clinical stage I-III, operated by an open or laparoscopic approach over a 4-year period, stratified into two groups according to the level of ligation of the inferior mesenteric artery (IMA) and vein - high tie - at the site of the origin  (1 cm) from aorta and low tie - distal to the origin of the left colic artery. The comparative indicators included the anastomotic leakage rate, the number of lymph nodes harvested with a metastatic lymph node index, a 3-year disease-free survival (DFS), disease-related survival OS. The follow-up period was 12-48 months.Results: For the period 2014-2018 a total of 217 patients with cancer of the sigmoid colon or rectum underwent 169 laparoscopic and 48 open surgeries. The distribution was as follows: 69% high ligation compared to 31% low ligation; 52 in an emergency or delayed emergency manner; 58% male and 42% female, mean age 64 ± 0.8 years; 56% in clinical stage III, 40% in II and only 4% in clinical stage I, relatively evenly distributed in the two target groups. There were wide variations in the number of lymph nodes harvested from the specimen (n = 4 to 22) for both groups without significant differences in the metastatic index. There was no statistically significant difference in the incidence of anastomotic leaks for both groups (3.8% for HT versus 3.0% for LT). With respect to the 3-year disease-free interval, there were also significant differences - 81.2% (HT) and 79.4% (LT) and the overall survival rate of 79.1% (HT) compared to 77.2% (LT) with a 72% follow-up coefficient.Discussion: The findings of this study are broadly consistent with those published so far and analyzed in three systematic reviews - the last one in 2018. This indicates that no statistically significant difference between high and low vascular ligation has been identified for the most important comparative indicators. It is extremely important to discuss several technical issues at present - contemporary problems requiring future high-quality clinical trials: the necessity and means of implementing left colic flexure mobilization in both types of vascular ligation with the lack of standardization; adequate and accurate identification of a correct cleavage plane of the dissection with differentiation of target vascular areas, avoiding erroneous entry into the sigmoid mesentery along with separate ligation of sigmoid vessels - oncologically inappropriate; sequence and level of ligation of the lower mesenteric vein with wide variations; pathoanatomic processing of the specimen with adequate isolation and examination of the removed lymph nodes, respectively adequacy of the pathohistological N-staging as well as the quality of the mesorectal excision; the need for stage control of the microvascular perfusion of the anastomosis segments by ICG fluorescence on the already validated global methods (hence the prevention of anastomotic leaks); progress in the importance and technical feasibility of low tie vascular ligation + perivascular lymph dissection to the IMA origin, and complete mesocolic excision (CME) in colon carcinoma (similar to TME in the rectal), the subject of more and more current studies; the specifics and advantages of robotic surgery of left-sided colon and rectal cancer with respect to accuracy of vascular and lymphatic dissection

A genome-wide association study suggests that a locus within the ataxin 2 binding protein 1 gene is associated with hand osteoarthritis: the Treat-OA consortium

To identify the susceptibility gene in hand osteoarthritis (OA) the authors used a two-stage approach genome-wide association study using two discovery samples (the TwinsUK cohort and the Rotterdam discovery subset; a total of 1804 subjects) and four replication samples (the Chingford Study, the Chuvasha Skeletal Aging Study, the Rotterdam replication subset and the Genetics, Arthrosis, and Progression (GARP) Study; a total of 3266 people). Five single-nucleotide polymorphisms (SNPs) had a likelihood of association with hand OA in the discovery stage and one of them (rs716508), was successfully confirmed in the replication stage (meta-analysis p = 1.81×10−5). The C allele conferred a reduced risk of 33% to 41% using a case–control definition. The SNP is located in intron 1 of the A2BP1 gene. This study also found that the same allele of the SNP significantly reduced bone density at both the hip and spine (p<0.01), suggesting the potential mechanism of the gene in hand OA might be via effects on subchondral bone. The authors' findings provide a potential new insight into genetic mechanisms in the development of hand OA

The listening talker: A review of human and algorithmic context-induced modifications of speech

International audienceSpeech output technology is finding widespread application, including in scenarios where intelligibility might be compromised - at least for some listeners - by adverse conditions. Unlike most current algorithms, talkers continually adapt their speech patterns as a response to the immediate context of spoken communication, where the type of interlocutor and the environment are the dominant situational factors influencing speech production. Observations of talker behaviour can motivate the design of more robust speech output algorithms. Starting with a listener-oriented categorisation of possible goals for speech modification, this review article summarises the extensive set of behavioural findings related to human speech modification, identifies which factors appear to be beneficial, and goes on to examine previous computational attempts to improve intelligibility in noise. The review concludes by tabulating 46 speech modifications, many of which have yet to be perceptually or algorithmically evaluated. Consequently, the review provides a roadmap for future work in improving the robustness of speech output

Speech produced in noise: Relationship between listening difficulty and acoustic and durational parameters.

Conversational speech produced in noise can be characterised by increases in intelligibility relative to such speech produced in quiet. Listening difficulty (LD) is a metric that can be used to evaluate speech transmission performance more sensitively than intelligibility scores in situations in which performance is likely to be high. The objectives of the present study were to evaluate the LD of speech produced in different noise and style conditions, to evaluate the spectral and durational speech modifications associated with these conditions, and to determine whether any of the spectral and durational parameters predicted LD. Nineteen subjects were instructed to speak at normal and loud volumes in the presence of background noise at 40.5 dB(A) and babble noise at 61 dB(A). The speech signals were amplitude-normalised, combined with pink noise to obtain a signal-to-noise ratio of -6 dB, and presented to twenty raters who judged their LD. Vowel duration, fundamental frequency and the proportion of the spectral energy in high vs low frequencies increased with the noise level within both styles. LD was lowest when the speech was produced in the presence of high level noise and at a loud volume, indicating improved intelligibility. Spectrum balance was observed to predict LD

Alternativní modely výnosových křivek

In this thesis, we focus on thorough yield curve modelling. We build on extended classical Nelson-Siegel model, which we further develop to accommodate unobserved regional common factors and principal components. We centre our discussion on central European currencies' yield curves: CZK, HUF, PLN and SKK. We propose two novel models to capture regional dynamics; one based purely on state space formulation and the other relying also on principal components of the regional yield curves. Moreover, we supplement the models with two application examples in risk management and structural break detection. The main contribution of this thesis is a creation of a complete framework that enables us to analyse yield curves, to design risk scenarios and to detect structural breaks of various types.Tato diplomová práce představuje několik modelů výnosových křivek. Vycházíme z dynamického modelu Nelson-Siegel, který jsme dále rozšířili pro modelování regionálních latentních faktorů a hlavních komponentů. Naši analýzu převážně zaměříme na středoevropské výnosové křivky denominované v těchto měnách: CZK, HUF, PLN a SKK. V této práci představujeme dva původní modely, které zachycují regionální dynamiku: první založen na "state space framework" a druhý navíc využívá metody hlavních komponent regionálních výnosových křivek. Práce dále obsahuje dvě praktické aplikace modelů na řízení rizik a na detekci strukturálních změn. Hlavním přinosem této diplomové práce je vytvoření komplexního rámce, který umožňuje analýzu výnosových křivek, přípravu krizových scénářů a detekci strukturálních změn.Institut ekonomických studiíInstitute of Economic StudiesFaculty of Social SciencesFakulta sociálních vě

Alternative yield curve modelling approach : regional models

In this thesis, we focus on thorough yield curve modelling. We build on extended classical Nelson-Siegel model, which we further develop to accommodate unobserved regional common factors and principal components. We centre our discussion on central European currencies' yield curves: CZK, HUF, PLN and SKK. We propose two novel models to capture regional dynamics; one based purely on state space formulation and the other relying also on principal components of the regional yield curves. Moreover, we supplement the models with two application examples in risk management and structural break detection. The main contribution of this thesis is a creation of a complete framework that enables us to analyse yield curves, to design risk scenarios and to detect structural breaks of various types

Alternativní modely výnosových křivek : regionální modely

Tato diplomová práce představuje několik modelů výnosových křivek. Vycházíme z dynamického modelu Nelson-Siegel, který jsme dále rozšířili pro modelování regionálních latentních faktorů a hlavních komponentů. Naši analýzu převážně zaměříme na středoevropské výnosové křivky denominované v těchto měnách: CZK, HUF, PLN a SKK. Hlavním přinosem této diplomové práce je vytvoření komplexního rámce, který umožňuje analýzu výnosových křivek, přípravu krizových scénářů a detekci strukturálních změn.In this thesis, we focus on thorough yield curve modelling. We build on extended classical Nelson-Siegel model, which we further develop to accommodate unobserved regional common factors and principal components. We centre our discussion on central European currencies' yield curves: CZK, HUF, PLN and SKK. We propose two novel models to capture regional dynamics; one based purely on state space formulation and the other relying also on principal components of the regional yield curves. Moreover, we supplement the models with two application examples in risk management and structural break detection. The main contribution of this thesis is a creation of a complete framework that enables us to analyse yield curves, to design risk scenarios and to detect structural breaks of various types.Institute of Economic StudiesInstitut ekonomických studiíFaculty of Social SciencesFakulta sociálních vě

Alternative field curve modelling approach : regional models

In this thesis, we focus on thorough yield curve modelling. We build on extended classical Nelson-Siegel model, which we further develop to accommodate unobserved regional common factors and principal components. We centre our discussion on central European currencies' yield curves: CZK, HUF, PLN and SKK. We propose two novel models to capture regional dynamics; one based purely on state space formulation and the other relying also on principal components of the regional yield curves. Moreover, we supplement the models with two application examples in risk management and structural break detection. The main contribution of this thesis is a creation of a complete framework that enables us to analyse yield curves, to design risk scenarios and to detect structural breaks of various types