Pattern Formation in Mesic Savannas

We analyze a spatially extended version of a well-known model of forest-savanna dynamics, which presents as a system of nonlinear partial integro-differential equations, and study necessary conditions for pattern-forming bifurcations. Homogeneous solutions dominate the dynamics of the standard forest-savanna model, regardless of the length scales of the various spatial processes considered. However, several different pattern-forming scenarios are possible upon including spatial resource limitation, such as competition for water, soil nutrients, or herbivory effects. Using numerical simulations and continuation, we study the nature of the resulting patterns as a function of system parameters and length scales, uncovering subcritical pattern-forming bifurcations and observing significant regions of multistability for realistic parameter regimes. Finally, we discuss our results in the context of extant savanna-forest modeling efforts and highlight ongoing challenges in building a unifying mathematical model for savannas across different rainfall levels

Variability of automated carotid intima-media thickness measurements by novice operators

Carotid intima-media thickness (C-IMT) measurements provide a non-invasive assessment of subclinical atherosclerosis. The aim of the study was to assess the inter- and intra-observer variability of automated C-IMT measurements undertaken by two novice operators using the Panasonic CardioHealth Station. Participants were free from cardio-metabolic disease, and each underwent serial bilateral C-IMT ultrasound measurements. Immediate interoperator measurement variability was calculated by comparing initial measurements taken by two operators. Immediate retest variability was calculated from two consecutive measurements and longer term variability was assessed by conducting a further scan 1 week later. Fifty apparently healthy participants (n = 20 females), aged 26·2 ± 5·0 years, were recruited. Operator 1 recorded a median (interquartile range) right and left-sided C-IMT of 0·471 mm (0·072 mm) and 0·462 mm (0·047 mm). Female's right and left C-IMT were 0·442 mm (0·049 mm) and 0·451 mm (0·063 mm), respectively. The limits of agreement (LoA) for immediate interoperator variability were −0·063 to 0·056 mm (mean bias −0·003 mm). Operator 1's immediate retest intra-operator LoA were −0·057 to 0·046 mm (mean bias was −0·005 mm). One-week LoA were −0·057 to 0·050 mm (mean bias −0·003 mm). Operator 2 recorded median right and left-sided C-IMT of 0·467 mm (0·089 mm) and 0·458 mm (0·046 mm) for males, respectively, whilst female measurements were 0·441 mm (0·052 mm) and 0·444 mm (0·054 mm), respectively. Operator 2's intra-operator immediate retest LoA were −0·056 to 0·056 (mean bias <−0·001 mm). Intra-operator LoA at 1 week were −0·052 to 0·068 mm (mean bias 0·008 mm). Novice operators produce acceptable short-term and 1-week inter- and intra-operator C-IMT measurement variability in healthy, young to middle-aged adults using the Panasonic CardioHealth Station

Market ecologies: The effect of information on the interaction and profitability of technical trading strategies

Technical trading strategies make profits by identifying and exploiting patterns in market prices—patterns generated by the interaction of market participants. Using a model market populated by individuals using a range of trading rules we show that the presence of technical traders may be beneficial, in some cases reducing volatility and increasing price efficiency. In particular, contrarian traders who base their decisions on high frequency data have the largest positive effect. It is also found that if technical traders condition their actions using ‘real time’ information, they partially emulate arbitrageurs and make positive profits

Peripheral and central arterial pressure and its relationship to vascular target organ damage in carotid artery, retina and arterial stiffness. Development and validation of a tool. The Vaso risk study

<p>Abstract</p> <p>Background</p> <p>Ambulatory blood pressure monitoring (ABPM) shows a better correlation to target organ damage and cardiovascular morbidity-mortality than office blood pressure. A loss of arterial elasticity and an increase in carotid artery intima-media thickness (IMT) has been associated with increased cardiovascular morbidity-mortality. Tools have been developed that allow estimation of the retinal arteriovenous index but not all studies coincide and there are contradictory results in relation to the evolution of the arteriosclerotic lesions and the caliber of the retinal vessels. The purpose of this study is to analyze the relationship between peripheral and central arterial pressure (clinic and ambulatory) and vascular structure and function as evaluated by the carotid artery intima-media thickness, retina arteriovenous index, pulse wave velocity (PWV) and ankle-brachial index in patients with and without type 2 diabetes. In turn, software is developed and validated for measuring retinal vessel thickness and automatically estimating the arteriovenous index.</p> <p>Methods/Design</p> <p>A cross-sectional study involving a control group will be made, with a posterior 4-year follow-up period in primary care. The study patients will be type 2 diabetics, with a control group of non-diabetic individuals. Consecutive sampling will be used to include 300 patients between 34-75 years of age and no previous cardiovascular disease, one-half being assigned to each group. Main measurements: age, gender, height, weight and abdominal circumference. Lipids, creatinine, microalbuminuria, blood glucose, HbA1c, blood insulin, high sensitivity C-reactive protein and endothelial dysfunction markers. Clinic and ambulatory blood pressure monitoring. Carotid ultrasound to evaluate IMT, and retinography to evaluate the arteriovenous index. ECG to assess left ventricle hypertrophy, ankle-brachial index, and pulse wave analysis (PWA) and pulse wave velocity (PWV) with the Sphigmocor System.</p> <p>Discussion</p> <p>We hope to obtain information on the correlation of different ABPM-derived parameters and PWA to organ target damage - particularly vascular structure and function evaluated from the IMT and PWV - and endothelial dysfunction in patients with and without type 2 diabetes. We also hope to demonstrate the usefulness of the instrument developed for the automated evaluation of retinal vascularization in the early detection of alterations in vascular structure and function and in the prognosis of middle-term cardiovascular morbidity.</p> <p>Trial Registration</p> <p>Clinical Trials.gov Identifier: <a href="http://www.clinicaltrials.gov/ct2/show/NCT01325064">NCT01325064</a></p

Prognostic impact of multidrug resistance gene expression on the management of breast cancer in the context of adjuvant therapy based on a series of 171 patients

Study of the prognostic impact of multidrug resistance gene expression in the management of breast cancer in the context of adjuvant therapy. This study involved 171 patients treated by surgery, adjuvant chemotherapy±radiotherapy±hormonal therapy (mean follow-up: 55 months). We studied the expression of multidrug resistance gene 1 (MDR1), multidrug resistance-associated protein (MRP1), and glutathione-S-transferase P1 (GSTP1) using a standardised, semiquantitative rt–PCR method performed on frozen samples of breast cancer tissue. Patients were classified as presenting low or high levels of expression of these three genes. rt-PCR values were correlated with T stage, N stage, Scarff–Bloom–Richardson (SBR) grade, age and hormonal status. The impact of gene expression levels on 5-year disease-free survival (DFS) and overall survival (OS) was studied by univariate and multivariate Cox analysis. No statistically significant correlation was demonstrated between MDR1, MRP1 and GSTP1 expressions. On univariate analysis, DFS was significantly decreased in a context of low GSTP1 expression (P=0.0005) and high SBR grade (P=0.003), size ⩾5 cm (P=0.038), high T stage (P=0.013), presence of intravascular embolus (P=0.034), and >3 N+ (P=0.05). On multivariate analysis, GSTP1 expression and the presence of ER remained independent prognostic factors for DFS. GSTP1 expression did not affect OS. The levels of MDR1 and MRP1 expression had no significant influence on DFS or OS. GSTP1 expression can be considered to be an independent prognostic factor for DFS in patients receiving adjuvant chemotherapy for breast cancer

New Approaches in the Differentiation of Human Embryonic Stem Cells and Induced Pluripotent Stem Cells toward Hepatocytes

Orthotropic liver transplantation is the only established treatment for end-stage liver diseases. Utilization of hepatocyte transplantation and bio-artificial liver devices as alternative therapeutic approaches requires an unlimited source of hepatocytes. Stem cells, especially embryonic stem cells, possessing the ability to produce functional hepatocytes for clinical applications and drug development, may provide the answer to this problem. New discoveries in the mechanisms of liver development and the emergence of induced pluripotent stem cells in 2006 have provided novel insights into hepatocyte differentiation and the use of stem cells for therapeutic applications. This review is aimed towards providing scientists and physicians with the latest advancements in this rapidly progressing field

Innovation technologique et adaptation au changement climatique

Whilst a 2 or 3 degrees rise on earth appears inevitable, country's resilience to climate change has become a crucial issue. Whereas technologies may play a major role in the global effort to adapt to climate change, little is known about the development and diffusion of adaptation technologies. This thesis, made of four chapters presenting descriptive and econometric studies, attempts to fill this gap by analyzing both countries and firms innovation behavior in adaptation technologies over the last 30 years, relying on a unique patent database targeting adaptation technologies. The first chapter provides the first descriptive study of the global invention and transfer of adaptation technologies. The observations indicate that countries did not specifically direct their innovation efforts towards adaptation technologies over the last 25 years. These innovations are highly concentrated within a few countries and I find very limited international technology diffusion. Consequently, I highlight a mismatch between countries' adaptation needs and their access to technologies. In the second chapter, I assess the effectiveness of technologies as a tool to mitigate economic and human damages induced by tropical cyclones. This chapter shows that these technologies can reduce the number of deaths and economic damage induced by these events, and legitimizes the interest in technologies as a solution for climate change adaptation. The last two chapters detail the dynamics of the innovation in adaptation technologies following extreme weather events. These two studies, at the country level and then at the firm level, show innovators weakly react to these weather extremes, and they do not transfer their patents to countries affected by these hazards. Moreover, these chapters confirm that extreme events do not induce additional efforts of innovators towards innovation technologies, nor the implementation of innovation common to several countries. This worrying observation calls for the implementation of ambitious local, national and international policies in order to overcome the lack of innovation and access to adaptation technologies, and thus induce a real transition in innovation toward these technologies.Alors qu'une augmentation d’au moins deux degrés de la température mondiale semble inévitable, la résilience au changement climatique est devenue une préoccupation majeure. Alors que les technologies peuvent jouer un rôle déterminant dans l’adaptation au changement climatique, on sait peu de choses sur le développement et la diffusion des technologies d'adaptation. Cette thèse, composée de quatre chapitres présentant des études descriptives et économétriques, utilise une base de données de brevets unique pour examiner le comportement d'innovation des pays et des entreprises en lien avec les technologies d'adaptation. Le premier chapitre montre que les pays ne dirigent pas spécifiquement leur effort d’innovation vers les technologies d’adaptation. Ces innovations sont très concentrées au sein de quelques pays et très peu diffusées internationalement, causant une inadéquation entre les besoins d’adaptation des pays et leur accès aux technologies. Dans le second chapitre, j’évalue l’efficacité des technologies comme outil de protection contre les dommages économiques et humains induits par les cyclones tropicaux. Ce chapitre prouve que ces technologies permettent de réduire le nombre de morts et les dégâts économiques induits par ces évènements, et légitime l’intérêt porté aux technologies comme solution pour l’adaptation au changement climatique. Les deux derniers chapitres détaillent la dynamique de l’innovation dans les technologies d’adaptation à la suite d’évènements climatiques extrêmes. Ces deux études, à l’échelle des pays puis des entreprises, montrent que les innovateurs réagissent faiblement à ces extrêmes météorologiques, et qu’ils transfèrent peu leurs brevets aux pays affectés par ces aléas. De plus, ces chapitres confirment que les évènements extrêmes n’induisent pas d’efforts supplémentaires des innovateurs vers les technologies d’innovation, ni la mise en place d’innovation commune à plusieurs pays. Ce constat préoccupant plaide pour la mise en place de politiques locales, nationales et internationales ambitieuses afin de pallier le manque d’innovation et d’accès aux technologies d’adaptation, et ainsi induire une réelle transition de l’innovation vers ces technologies

Innovation technologique et adaptation au changement climatique

Alors qu'une augmentation d’au moins deux degrés de la température mondiale semble inévitable, la résilience au changement climatique est devenue une préoccupation majeure. Alors que les technologies peuvent jouer un rôle déterminant dans l’adaptation au changement climatique, on sait peu de choses sur le développement et la diffusion des technologies d'adaptation. Cette thèse, composée de quatre chapitres présentant des études descriptives et économétriques, utilise une base de données de brevets unique pour examiner le comportement d'innovation des pays et des entreprises en lien avec les technologies d'adaptation. Le premier chapitre montre que les pays ne dirigent pas spécifiquement leur effort d’innovation vers les technologies d’adaptation. Ces innovations sont très concentrées au sein de quelques pays et très peu diffusées internationalement, causant une inadéquation entre les besoins d’adaptation des pays et leur accès aux technologies. Dans le second chapitre, j’évalue l’efficacité des technologies comme outil de protection contre les dommages économiques et humains induits par les cyclones tropicaux. Ce chapitre prouve que ces technologies permettent de réduire le nombre de morts et les dégâts économiques induits par ces évènements, et légitime l’intérêt porté aux technologies comme solution pour l’adaptation au changement climatique. Les deux derniers chapitres détaillent la dynamique de l’innovation dans les technologies d’adaptation à la suite d’évènements climatiques extrêmes. Ces deux études, à l’échelle des pays puis des entreprises, montrent que les innovateurs réagissent faiblement à ces extrêmes météorologiques, et qu’ils transfèrent peu leurs brevets aux pays affectés par ces aléas. De plus, ces chapitres confirment que les évènements extrêmes n’induisent pas d’efforts supplémentaires des innovateurs vers les technologies d’innovation, ni la mise en place d’innovation commune à plusieurs pays. Ce constat préoccupant plaide pour la mise en place de politiques locales, nationales et internationales ambitieuses afin de pallier le manque d’innovation et d’accès aux technologies d’adaptation, et ainsi induire une réelle transition de l’innovation vers ces technologies.Whilst a 2 or 3 degrees rise on earth appears inevitable, country's resilience to climate change has become a crucial issue. Whereas technologies may play a major role in the global effort to adapt to climate change, little is known about the development and diffusion of adaptation technologies. This thesis, made of four chapters presenting descriptive and econometric studies, attempts to fill this gap by analyzing both countries and firms innovation behavior in adaptation technologies over the last 30 years, relying on a unique patent database targeting adaptation technologies. The first chapter provides the first descriptive study of the global invention and transfer of adaptation technologies. The observations indicate that countries did not specifically direct their innovation efforts towards adaptation technologies over the last 25 years. These innovations are highly concentrated within a few countries and I find very limited international technology diffusion. Consequently, I highlight a mismatch between countries' adaptation needs and their access to technologies. In the second chapter, I assess the effectiveness of technologies as a tool to mitigate economic and human damages induced by tropical cyclones. This chapter shows that these technologies can reduce the number of deaths and economic damage induced by these events, and legitimizes the interest in technologies as a solution for climate change adaptation. The last two chapters detail the dynamics of the innovation in adaptation technologies following extreme weather events. These two studies, at the country level and then at the firm level, show innovators weakly react to these weather extremes, and they do not transfer their patents to countries affected by these hazards. Moreover, these chapters confirm that extreme events do not induce additional efforts of innovators towards innovation technologies, nor the implementation of innovation common to several countries. This worrying observation calls for the implementation of ambitious local, national and international policies in order to overcome the lack of innovation and access to adaptation technologies, and thus induce a real transition in innovation toward these technologies

Innovation technologique et adaptation au changement climatique

Whilst a 2 or 3 degrees rise on earth appears inevitable, country's resilience to climate change has become a crucial issue. Whereas technologies may play a major role in the global effort to adapt to climate change, little is known about the development and diffusion of adaptation technologies. This thesis, made of four chapters presenting descriptive and econometric studies, attempts to fill this gap by analyzing both countries and firms innovation behavior in adaptation technologies over the last 30 years, relying on a unique patent database targeting adaptation technologies. The first chapter provides the first descriptive study of the global invention and transfer of adaptation technologies. The observations indicate that countries did not specifically direct their innovation efforts towards adaptation technologies over the last 25 years. These innovations are highly concentrated within a few countries and I find very limited international technology diffusion. Consequently, I highlight a mismatch between countries' adaptation needs and their access to technologies. In the second chapter, I assess the effectiveness of technologies as a tool to mitigate economic and human damages induced by tropical cyclones. This chapter shows that these technologies can reduce the number of deaths and economic damage induced by these events, and legitimizes the interest in technologies as a solution for climate change adaptation. The last two chapters detail the dynamics of the innovation in adaptation technologies following extreme weather events. These two studies, at the country level and then at the firm level, show innovators weakly react to these weather extremes, and they do not transfer their patents to countries affected by these hazards. Moreover, these chapters confirm that extreme events do not induce additional efforts of innovators towards innovation technologies, nor the implementation of innovation common to several countries. This worrying observation calls for the implementation of ambitious local, national and international policies in order to overcome the lack of innovation and access to adaptation technologies, and thus induce a real transition in innovation toward these technologies.Alors qu'une augmentation d’au moins deux degrés de la température mondiale semble inévitable, la résilience au changement climatique est devenue une préoccupation majeure. Alors que les technologies peuvent jouer un rôle déterminant dans l’adaptation au changement climatique, on sait peu de choses sur le développement et la diffusion des technologies d'adaptation. Cette thèse, composée de quatre chapitres présentant des études descriptives et économétriques, utilise une base de données de brevets unique pour examiner le comportement d'innovation des pays et des entreprises en lien avec les technologies d'adaptation. Le premier chapitre montre que les pays ne dirigent pas spécifiquement leur effort d’innovation vers les technologies d’adaptation. Ces innovations sont très concentrées au sein de quelques pays et très peu diffusées internationalement, causant une inadéquation entre les besoins d’adaptation des pays et leur accès aux technologies. Dans le second chapitre, j’évalue l’efficacité des technologies comme outil de protection contre les dommages économiques et humains induits par les cyclones tropicaux. Ce chapitre prouve que ces technologies permettent de réduire le nombre de morts et les dégâts économiques induits par ces évènements, et légitime l’intérêt porté aux technologies comme solution pour l’adaptation au changement climatique. Les deux derniers chapitres détaillent la dynamique de l’innovation dans les technologies d’adaptation à la suite d’évènements climatiques extrêmes. Ces deux études, à l’échelle des pays puis des entreprises, montrent que les innovateurs réagissent faiblement à ces extrêmes météorologiques, et qu’ils transfèrent peu leurs brevets aux pays affectés par ces aléas. De plus, ces chapitres confirment que les évènements extrêmes n’induisent pas d’efforts supplémentaires des innovateurs vers les technologies d’innovation, ni la mise en place d’innovation commune à plusieurs pays. Ce constat préoccupant plaide pour la mise en place de politiques locales, nationales et internationales ambitieuses afin de pallier le manque d’innovation et d’accès aux technologies d’adaptation, et ainsi induire une réelle transition de l’innovation vers ces technologies