Detecting Turning Points with Many Predictors through Hidden Markov Models

This paper explores the American business cycle with the Hidden Markov Model (HMM) as a monitoring tool using monthly data. It exhibits ten US time series which offer reliable information to detect recessions in real time. It also proposes and assesses the performances of different and complementary “recession models” based on Markovian processes, discusses the most efficient and easiest way of encompassing information through these models and draws three main conclusions: simple HMM are decisive to monitor the business cycle and some series are proved highly reliable; more sophisticated models such as the Dynamic Factor with Markov Switching (DFMS) model or Stock and Watson’s Experimental Recession Index seem not to be more powerful than simple (univariate or pseudo-multivariate) Hidden Markov Models, which remain far more parsimonious; combining information in temporal space seems to work marginally better than in probability space for high frequency data. We conclude about leading and “real time detection” properties related to HMM and give some hints for further research.Business Cycle, Markov Switching, Dynamic Factor, Coincident Indicators

Etude comparative du rôle de la dynamique et de la chimie dans la modélisation de l'atmosphère moyenne

L'importance du rôle de l'atmosphère moyenne dans le forçage des autres composantes du système climatique est aujourd'hui largement reconnue. Cela tient notamment à la place centrale occupée par l'ozone dans le bilan radiatif de l'atmosphère et aux conséquences sur la circulation atmosphérique de la destruction de l'ozone. Il apparaît également que la dynamique de la stratosphère influence de manière substantielle la variabilité dans la troposphère. Durant cette thèse, nous nous sommes attachés à développer des pistes d'amélioration de la modélisation de l'atmosphère moyenne dans le modèle de circulation générale, ARPEGE-Climat, tout en examinant le rôle potentiel de cette amélioration dans la circulation troposphérique. Nous étudions tout d'abord, par des expériences numériques idéalisées, l'influence de la stratosphère équatoriale sur la dynamique extra-tropicale. Cette étude montre sans ambiguïté qu'une simulation précise de la circulation aux hautes latitudes de l'hémisphère nord ne peut se passer d'une représentation réaliste de la stratosphère tropicale. Nous décrivons ensuite la mise en oeuvre d'une paramétrisation spectrale des ondes de gravité non orographiques dans le modèle ARPEGE-Climat. L'introduction de cette paramétrisation conduit à une distribution horizontale réaliste du flux de quantité de mouvement dans la stratosphère, à une amélioration de la représentation de la circulation en moyenne zonale ainsi qu'à une meilleure simulation de la variabilité stratosphérique équatoriale. Enfin, le travail s'est orienté sur le développement et la validation d'un modèle de chimie-climat (CNRM-CCM) pour lequel le schéma chimique REPROBUS a été couplé avec le modèle ARPEGE-Climat. Ce nouveau modèle apparaît comme un outil approprié pour l'étude des interactions chimie-climat. L'introduction d'une chimie stratosphérique interactive permet de réduire certains biais chauds à la stratopause tropicale et de représenter de manière plus réaliste les vortex polaires hivernaux.The importance of the role played by the middle atmosphere in forcing other parts of the climate system is now generally recognized. A major reason is the central role of stratospheric ozone as a climate gas and the resulting issues of ozone depletion on the atmospheric circulation. There is also evidence that the stratosphere substantially affects the tropospheric variability through dynamical processes. This PhD aims to investigate this influence through improving middle atmosphere modelling in the general circulation model, ARPEGE-Climat. By using a set of idealized ensemble experiments, we first study the sensitivity of the northern hemispheric winter climate to the equatorial stratosphere circulation. The comparison between perturbed and control experiments reveals a significant influence on the extratropical stratospheric variability through an improved propagation of the planetary waves. We then describe results from a simulation in which a spectral parameterization for small-scale non-orographic gravity waves is introduced into the general circulation model, ARPEGE-Climat. They show a realistic horizontal distribution of momentum flux in the stratosphere, an improved representation of the zonal-mean circulation and temperature structure and a better simulation of the equatorial stratospheric variability. We finally present a description and evaluation of the chemistry-climate model, CNRM-CCM, which interactively combines the general circulation model ARPEGE-Climat with the stratospheric chemistry scheme REPROBUS. This new model appears as an appropriate tool to study chemistry-climate interactions. The introduction of a fully coupled chemistry improves the model dynamical climatology, with a substantial reduction of the temperature biases in the tropical stratopause region and a better representation of the winter polar vortices

Nonlinear aspects of the EEG during sleep in children

Electroencephalograph (EEG) analysis enables the neuronal behavior of a section of the brain to be examined. If the behavior is nonlinear then nonlinear tools can be used to glean information on brain behavior, and aid in the diagnosis of sleep abnormalities such as obstructive sleep apnea syndrome (OSAS). In this paper the sleep EEGs of a set of normal and mild OSAS children are evaluated for nonlinear behaviour. We consider how the behaviour of the brain changes with sleep stage and between normal and OSAS children.Comment: 9 pages, 2 figures, 4 table

Upper Cretaceous amber from Vendée, north-western France:Age dating and geological, chemical, and palaeontological characteristics

International audienceThe Upper Cretaceous lignite deposits of La Garnache, Vendée (western France), consist of two lignitic clay series, Garnache 1 and Garnache 2, separated by a fault. The first series cropped out to the south of the fault during road works until 2002 but is now covered by an embankment. It has provided numerous pieces of amber containing arthropod and microorganism inclusions. The second lignitic series, exposed to the north of the fault, is rich in fossil wood but devoid of amber. Palynological analysis of Garnache 1 revealed several Normapolles species belonging to the genera Atlantopollis, Complexiopollis, Osculapollis, Plicapollis and Trudopollis, but larger forms typical of Senonian deposits are absent. By contrast, Garnache 2 proved to be dominated taxonomically and numerically by spores (Appendicisporites, Camarozonosporites, Gleicheniidites, Patellasporites, Stereisporites), associated with a few gymnosperm (Cerebropollenites, Phyllocladidites, Classopollis) and angiosperm (Liliacidites, Retitricolpites and a single specimen of the Normapolles Complexiopollis) taxa. Garnache 1 is, therefore, younger than Garnache 2, the latter being clearly Cenomanian in age whereas Garnache 1 is more likely to be Turonian. Lignitic clay of Garnache 1 contains numerous translucent, orange to red, pieces of amber. Vendean amber is rich in aquatic arthropods, such as tanaids and epicarideans (Crustacea), as well as marine or brackish siliceous microorganisms such as diatoms and sponge spicules. These aquatic inclusions indicate that resin-producing trees grew along and close to the seashore. The amber-bearing clay was deposited in a calm, estuarine or lagoonal, muddy environment

Variación intraespecífica e individual de los pelos de mamíferos del Estado de México: implicaciones en la identificación interespecífica

Se determinó la variación del pelo de guardia dorsal entre individuos de la misma especie y se comparó la variación de un individuo en diferentes regiones. Se midió la longitud total y diámetro de la médula, además se determinó el patrón de tonalidad y tipo de médula. En la comparación intraespecífica se caracterizaron 530 pelos de guardia dorsales de 53 organismos. A pesar de las variaciones en la longitud y diámetro de la médula, puede realizarse una identificación exitosa de los organismos en un plano específico utilizando la guía de identificación de mamíferos terrestres a partir del pelo de guardia, excepto para Canis latrans y Liomys irroratus. En la comparación individual se describieron 560 pelos de guardia de 14 especies. Se encontraron diferencias en la longitud total del pelo, en el diámetro de la médula y en la coloración; el único carácter que permaneció constante fue la médula.Se determinó la variación del pelo de guardia dorsal entre individuos de la misma especie y se comparó la variación de un individuo en diferentes regiones. Se midió la longitud total y diámetro de la médula, además se determinó el patrón de tonalidad y tipo de médula. En la comparación intraespecífica se caracterizaron 530 pelos de guardia dorsales de 53 organismos. A pesar de las variaciones en la longitud y diámetro de la médula, puede realizarse una identificación exitosa de los organismos en un plano específico utilizando la guía de identificación de mamíferos terrestres a partir del pelo de guardia, excepto para Canis latrans y Liomys irroratus. En la comparación individual se describieron 560 pelos de guardia de 14 especies. Se encontraron diferencias en la longitud total del pelo, en el diámetro de la médula y en la coloración; el único carácter que permaneció constante fue la médula

Cloud feedbacks in extratopical cyclones: insight from long-term satellite data and high-resolution global simulations

A negative extratropical shortwave cloud feedback driven by changes in cloud optical depth is a feature of global climate models (GCMs). A robust positive trend in observed liquid water path (LWP) over the last two decades across the warming Southern Ocean supports the negative shortwave cloud feedback predicted by GCMs. This feature has been proposed to be due to transitions from ice to liquid with warming. To gain insight into the shortwave cloud feedback we examine extratropical cyclone variability and the response of extratropical cyclones to transient warming in GCM simulations. Multi-Sensor Advanced Climatology Liquid Water Path (MAC-LWP) microwave observations of cyclone properties from the period 1992–2015 are contrasted with GCM simulations, with horizontal resolutions ranging from 7 km to hundreds of kilometers. We find that inter-cyclone variability in LWP in both observations and models is strongly driven by the moisture flux along the cyclone's warm conveyor belt (WCB). Stronger WCB moisture flux enhances the LWP within cyclones. This relationship is replicated in GCMs, although its strength varies substantially across models. It is found that more than 80 % of the enhancement in Southern Hemisphere (SH) extratropical cyclone LWP in GCMs in response to a transient 4 K warming can be predicted based on the relationship between the WCB moisture flux and cyclone LWP in the historical climate and their change in moisture flux between the historical and warmed climates. Further, it is found that that the robust trend in cyclone LWP over the Southern Ocean in observations and GCMs is consistent with changes in the moisture flux. We propose two cloud feedbacks acting within extratropical cyclones: a negative feedback driven by Clausius–Clapeyron increasing water vapor path (WVP), which enhances the amount of water vapor available to be fluxed into the cyclone, and a feedback moderated by changes in the life cycle and vorticity of cyclones under warming, which changes the rate at which existing moisture is imported into the cyclone. Both terms contribute to increasing LWP within the cyclone. While changes in moisture flux predict cyclone LWP trends in the current climate and the majority of changes in LWP in transient warming simulations, a portion of the LWP increase in response to climate change that is unexplained by increasing moisture fluxes may be due to phase transitions. The variability in LWP within cyclone composites is examined to understand what cyclonic regimes the mixed-phase cloud feedback is relevant to. At a fixed WCB moisture flux cyclone LWP increases with increasing sea surface temperature (SST) in the half of the composite poleward of the low and decreases in the half equatorward of the low in both GCMs and observations. Cloud-top phase partitioning observed by the Atmospheric Infrared Sounder (AIRS) indicates that phase transitions may be driving increases in LWP in the poleward half of cyclones

KDM6B drives epigenetic reprogramming associated with lymphoid stromal cell early commitment and immune properties

Mature lymphoid stromal cells (LSCs) are key organizers of immune responses within secondary lymphoid organs. Similarly, inflammation-driven tertiary lymphoid structures depend on immunofibroblasts producing lymphoid cytokines and chemokines. Recent studies have explored the origin and heterogeneity of LSC/immunofibroblasts, yet the molecular and epigenetic mechanisms involved in their commitment are still unknown. This study explored the transcriptomic and epigenetic reprogramming underlying LSC/immunofibroblast commitment. We identified the induction of lysine demethylase 6B (KDM6B) as the primary epigenetic driver of early immunofibroblast differentiation. In addition, we observed an enrichment for KDM6B gene signature in murine inflammatory fibroblasts and pathogenic stroma of patients with autoimmune diseases. Last, KDM6B was required for the acquisition of LSC/immunofibroblast functional properties, including the up-regulation of CCL2 and the resulting recruitment of monocytes. Overall, our results reveal epigenetic mechanisms that participate in the early commitment and immune properties of immunofibroblasts and support the use of epigenetic modifiers as fibroblast-targeting strategies in chronic inflammation

KDM6B drives epigenetic reprogramming associated with lymphoid stromal cell early commitment and immune properties

Mature lymphoid stromal cells (LSCs) are key organizers of immune responses within secondary lymphoid organs. Similarly, inflammation-driven tertiary lymphoid structures depend on immunofibroblasts producing lymphoid cytokines and chemokines. Recent studies have explored the origin and heterogeneity of LSC/immunofibroblasts, yet the molecular and epigenetic mechanisms involved in their commitment are still unknown. This study explored the transcriptomic and epigenetic reprogramming underlying LSC/immunofibroblast commitment. We identified the induction of lysine demethylase 6B (KDM6B) as the primary epigenetic driver of early immunofibroblast differentiation. In addition, we observed an enrichment for KDM6B gene signature in murine inflammatory fibroblasts and pathogenic stroma of patients with autoimmune diseases. Last, KDM6B was required for the acquisition of LSC/immunofibroblast functional properties, including the up-regulation of CCL2 and the resulting recruitment of monocytes. Overall, our results reveal epigenetic mechanisms that participate in the early commitment and immune properties of immunofibroblasts and support the use of epigenetic modifiers as fibroblast-targeting strategies in chronic inflammation

Fostering implementation of health services research findings into practice: a consolidated framework for advancing implementation science

Abstract Background Many interventions found to be effective in health services research studies fail to translate into meaningful patient care outcomes across multiple contexts. Health services researchers recognize the need to evaluate not only summative outcomes but also formative outcomes to assess the extent to which implementation is effective in a specific setting, prolongs sustainability, and promotes dissemination into other settings. Many implementation theories have been published to help promote effective implementation. However, they overlap considerably in the constructs included in individual theories, and a comparison of theories reveals that each is missing important constructs included in other theories. In addition, terminology and definitions are not consistent across theories. We describe the Consolidated Framework For Implementation Research (CFIR) that offers an overarching typology to promote implementation theory development and verification about what works where and why across multiple contexts. Methods We used a snowball sampling approach to identify published theories that were evaluated to identify constructs based on strength of conceptual or empirical support for influence on implementation, consistency in definitions, alignment with our own findings, and potential for measurement. We combined constructs across published theories that had different labels but were redundant or overlapping in definition, and we parsed apart constructs that conflated underlying concepts. Results The CFIR is composed of five major domains: intervention characteristics, outer setting, inner setting, characteristics of the individuals involved, and the process of implementation. Eight constructs were identified related to the intervention (e.g., evidence strength and quality), four constructs were identified related to outer setting (e.g., patient needs and resources), 12 constructs were identified related to inner setting (e.g., culture, leadership engagement), five constructs were identified related to individual characteristics, and eight constructs were identified related to process (e.g., plan, evaluate, and reflect). We present explicit definitions for each construct. Conclusion The CFIR provides a pragmatic structure for approaching complex, interacting, multi-level, and transient states of constructs in the real world by embracing, consolidating, and unifying key constructs from published implementation theories. It can be used to guide formative evaluations and build the implementation knowledge base across multiple studies and settings.http://deepblue.lib.umich.edu/bitstream/2027.42/78272/1/1748-5908-4-50.xmlhttp://deepblue.lib.umich.edu/bitstream/2027.42/78272/2/1748-5908-4-50-S1.PDFhttp://deepblue.lib.umich.edu/bitstream/2027.42/78272/3/1748-5908-4-50-S3.PDFhttp://deepblue.lib.umich.edu/bitstream/2027.42/78272/4/1748-5908-4-50-S4.PDFhttp://deepblue.lib.umich.edu/bitstream/2027.42/78272/5/1748-5908-4-50.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/78272/6/1748-5908-4-50-S2.PDFPeer Reviewe