Contribution of the analysis of diurnal cycles for understanding the mean seasonal cycle of rainforest photosynthetic activity in Central Africa. [P-2215-10]

Global carbon, water and energy cycles are substantially driven by vegetation phenology. In particular tropical rainforests have been shown to be a key component of the climate system as they act as major water vapor sources and carbon dioxide sink. For these reasons their evolution in response to both human pressure and climate change is critical. As compared to the Amazonian and Asian rainforests, the rainforest of Central Africa experiences slower deforestation rates, so that its main threat for the next decades might come from climate change. So far, the response and sensitivity of the Central Africa rainforest to the mean seasonal evolution and inter-annual variability of climate has attracted little interest. Indeed, most of the studies focus on its Amazonian counterpart and suggest that solar irradiation is the main driver of the annual and inter-annual variations of rainforest photosynthetic activity, and the Central Africa climate itself is not well documented. As a first step towards a better understanding of the Central Africa rainforest sensitivity to present-day climate variability and response to climate change, this study performs for a target region located between 0-5°N/12- 19°E (thus documenting forest areas from 5 countries) and using space borne observations, a detailed analysis of the rainforest photosynthetic activity mean seasonal cycle comparing it with those of climate variables considered as potential drivers, i.e. rainfall, cloudiness and solar irradiation. Several key points emerge from our study. First, the seasonal cycles of photosynthetic activity (EVI MODIS) and rainfall over our target region are both bimodal. However, the highest peak of EVI (March-May) coincides with the driest of the two rainy seasons while the lowest peak of EVI (September-October) coincides with the wettest of the two rainy seasons. Second, the two rainy seasons are not associated with two distinct lows in total solar irradiation and two distinct peaks in total cloudiness: the first rainy season (March-May) which is less rainy as compared to the second one (September-October), is also less cloudy and receives more total solar irradiation. This might explain the higher EVI values recorded. Third, the high total cloudiness recorded throughout the seasonal cycle actually hides marked seasonal variations in the frequency of the 5 main types of clouds analyzed. These cloud types have specific diurnal cycles which control those of solar irradiation (thus the daily light and energy available for photosynthesis), but also influence the remote sensed photosynthetic activity data (or index). Our results clearly show that (1) nor the two dry seasons, nor the two rainy seasons do compare in terms of mean rainfall, cloudiness, solar irradiation and temperature, and (2) water and light availability have a respective weight in the Central Africa rainforest photosynthetic activity which evolves throughout the seasonal cycle. They also suggest that any evolution, due to climate change, of the complex diurnal cycles of rainfall, nebulosity and solar irradiation which characterize the equatorial climate regimes might perturb the rainforest phenology and enhance these ecosystems vulnerability. (Texte intégral

Alien Registration- Philippon, Marie B. (Portland, Cumberland County)

https://digitalmaine.com/alien_docs/21315/thumbnail.jp

WARNING: Physics Envy May Be Hazardous To Your Wealth!

The quantitative aspirations of economists and financial analysts have for many years been based on the belief that it should be possible to build models of economic systems - and financial markets in particular - that are as predictive as those in physics. While this perspective has led to a number of important breakthroughs in economics, "physics envy" has also created a false sense of mathematical precision in some cases. We speculate on the origins of physics envy, and then describe an alternate perspective of economic behavior based on a new taxonomy of uncertainty. We illustrate the relevance of this taxonomy with two concrete examples: the classical harmonic oscillator with some new twists that make physics look more like economics, and a quantitative equity market-neutral strategy. We conclude by offering a new interpretation of tail events, proposing an "uncertainty checklist" with which our taxonomy can be implemented, and considering the role that quants played in the current financial crisis.Comment: v3 adds 2 reference

Diabete Aftricain en France

Introduction : Les auteurs rapportent le cas d’un diabète africain ou diabète atypique désigne un type spécifique de diabète présentant au départ des stigmates d’un diabète de type 1 mais dont l’évolution ultérieure se fait vers un diabète de type 2 avec la possibilité d’une longue phase de rémission. Il s’agit d’un sujet d’origine africaine, des spécificités diagnostiques, métaboliques, physiopathologiques et prise en charge de ce type de diabète. Patients et méthodes : Il s’agit d’une observation clinique d’un patient d’origine africaine vivant en France ayant un diabète atypique. Cas clinique : Patient âgé de 33 ans, a été hospitalisé pour une acidocétose diabétique. Il a un antécédent familial de diabète de type 2, un surpoids (IMC = 28,73 Kg/m2). Une insulinothérapie a été instaurée. Le bilan étiologique de cette décompensation métabolique et la recherche de d’anticorps anti-GAD et anti-IA2 sont négatifs. Après 3 mois d’insulinothérapie, on obtient un équilibre glycémique satisfaisant marqué par une HbA1c à 7 % et un peptide C remonté à 300 pmol/l (pour une GV à 1,09g/l). Au 6ème mois, le patient présente un parfait équilibre glycémique (HbA1C : 6,4 %), avec un peptide C qui s’est normalisé à 870 pmol/l (pour une GV à 1,29g/l). C’est ce qui a permis de proposer l’arrêt de l’insulinothérapie. Pour des raisons sociales, le patient refuse l’arrêt du traitement. Aucune anomalie n’a été objectivée au fond d’œil, ni à l’électrocardiogramme, ni à l’évaluation de la fonction rénale (Clairance de créatinine normale par MDRD et micro-albuminurie négative). Ce tableau clinique illustre un cas de diabète d’un africain. Il s’agit d’une expression clinique proche du diabète de type 1 (DT1) mais se caractérise par une rémission, plus lente que la lune de miel dans le DT1, avec une absence de stigmates d’auto-immunité. Il est considéré comme diabète atypique ou de type 1 idiopathique. Conclusion : Ce type de diabète évoque plusieurs hypothèses physiopathologiques. L’équilibre glycémique est rapidement obtenu sous insulinothérapie, avec possibilité de réémission   Introduction : The authors report the case of African diabetes or atypical diabetes refers to a specific type of diabetes presenting initially with the stigma of type 1 diabetes but whose subsequent evolution is towards type 2 diabetes with the possibility of a long remission phase. This is a subject of African origin, and the diagnostic, metabolic, pathophysiological, and management specificities of this type of diabetes. Patients and methods: This is a clinical observation of a patient of African origin living in France with atypical diabetes. Clinical case: A 33-year-old patient was hospitalized for diabetic ketoacidosis. He had a family history of type 2 diabetes and was overweight (BMI = 28.73 kg/m2). Insulin therapy was initiated. The aetiological assessment of this metabolic decompensation and the search for anti-GAD and anti-IA2 antibodies were negative. After 3 months of insulin therapy, a satisfactory glycaemic balance was obtained, marked by an HbA1c of 7% and a C-peptide of 300 pmol/l (for a GV of 1.09g/l). At the 6th month, the patient had perfect glycaemic control (HbA1C: 6.4%), with a C-peptide that had normalized to 870 pmol/l (for a GV of 1.29g/l). This was the basis for proposing the discontinuation of insulin therapy. For social reasons, the patient refused to stop the treatment. No abnormalities were observed on the fundus, electrocardiogram, or renal function tests (normal creatinine clearance by MDRD and negative microalbuminuria). This clinical picture illustrates a case of diabetes in an African. It is a clinical expression close to type 1 diabetes (T1DM) but is characterized by remission, slower than the honeymoon period in T1DM, with an absence of autoimmune stigma. It is considered atypical or idiopathic type 1 diabetes. Conclusion: This type of diabetes raises several pathophysiological hypotheses. Glycaemic control is rapidly achieved with insulin therapy, with the possibility of re-emissio

Diabete African en France

Introduction: Le diabète africain ou diabète atypique désigne un type spécifique de diabète présentant au départ des stigmates d’un diabète de type 1 mais dont l’évolution ultérieure se fait vers un diabète de type 2 avec la possibilité d’une longue phase de rémission. Nous discuterons dans cet article a travers un cas clinique chez un sujet d’origine africaine, des spécificités diagnostiques, métaboliques, physiopathologiques et prise en charge de ce type de diabète. Patients et méthodes : Il s’agit d’une observation clinique particulière d’un patient d’origine africaine vivant en France ayant un diabète atypique. Cas clinique : Patient, âgée de 33 ans, a été hospitalisé pour une acidocétose diabétique. Il a une hérédité familiale de diabète de type 2, un surpoids (IMC = 28,73 Kg/m2). Une insulinothérapie a été instaurée. Le bilan étiologique de cette décompensation métabolique et la recherche de d’anticorps anti-GAD et anti-IA2 sont négatifs. Après 3 mois d’insulinothérapie, on obtient un équilibre glycémique satisfaisant marqué par une HbA1c à 7 % et un peptide C remonté à 300 pmol/l (pour une GV à 1,09g/l). Au bilan du 6 mois, le patient présente un parfait équilibre glycémique (HbA1C : 6,4 %), avec un peptide C qui s’est normalisé à 870 pmol/l (pour une GV à 1,29g/l). C’est qui a permis de proposer l’arrêt de l’insulinothérapie malheureusement récusé par le patient pour des raisons sociales. Aucune anomalie n’a été objectivée au fond de l’œil, ni à l’électro-cardiogramme, ni à l’évaluation de la fonction rénale (Clairance de créatinine normale par MDRD et micro-albuminurie négative). Ce tableau clinique illustre un cas de diabète africain. Il s’agit d’une expression clinique proche du diabète de type 1 (DT1) mais se caractérise par une rémission, plus lente que la lune de miel dans le DT1, avec une absence de stigmates d’auto-immunité. Il est considéré comme diabète atypique ou de type 1 idiopathique. Discussion /Conclusion : Ce type de diabète évoque plusieurs hypothèses physiopathologiques. L’équilibre glycémique est rapidement obtenu sous insulinothérapie, avec possibilité de réémission.   African diabetes or atypical diabetes refers to a specific type of diabetes that initially presents with the stigma of type 1 diabetes but later progresses to type 2 diabetes with the possibility of a long remission phase. We will discuss in this article, through a clinical case in a subject of African origin, the diagnostic, metabolic, physiopathological and management specificities of this type of diabetes. Patients and methods: This is a particular clinical observation of a patient of African origin living in France with atypical diabetes. Clinical case: Patient, aged 33 years, was hospitalized for diabetic ketoacidosis. He had a family history of type 2 diabetes, was overweight (BMI = 28.73 Kg/m2). Insulin therapy was initiated. The etiological assessment of this metabolic decompensation and the search for anti-GAD and anti-IA2 antibodies were negative. After 3 months of insulin therapy, a satisfactory glycemic balance was obtained, marked by an HbA1c of 7% and a C-peptide of 300 pmol/l (for a GV of 1.09 g/l). At the 6-month check-up, the patient had perfect glycemic control (HbA1C: 6.4%), with a C-peptide that had normalized to 870 pmol/l (for a GV of 1.29g/l). This was the reason for proposing the discontinuation of insulin therapy, which was unfortunately rejected by the patient for social reasons. No abnormality was observed on the fundus, electrocardiogram or renal function tests (normal creatinine clearance by MDRD and negative microalbuminuria). This clinical picture illustrates a case of African diabetes. It is a clinical expression close to type 1 diabetes (T1DM) but is characterized by a remission, slower than the honeymoon in T1DM, with an absence of autoimmune stigma. It is considered atypical or idiopathic type 1 diabetes. Discussion/Conclusion : This type of diabetes raises several pathophysiological hypotheses. Glycemic control is rapidly obtained with insulin therapy, with the possibility of re-emission

Diabete African en France

Introduction: Le diabète africain ou diabète atypique désigne un type spécifique de diabète présentant au départ des stigmates d’un diabète de type 1 mais dont l’évolution ultérieure se fait vers un diabète de type 2 avec la possibilité d’une longue phase de rémission. Nous discuterons dans cet article a travers un cas clinique chez un sujet d’origine africaine, des spécificités diagnostiques, métaboliques, physiopathologiques et prise en charge de ce type de diabète. Patients et méthodes : Il s’agit d’une observation clinique particulière d’un patient d’origine africaine vivant en France ayant un diabète atypique. Cas clinique : Patient, âgée de 33 ans, a été hospitalisé pour une acidocétose diabétique. Il a une hérédité familiale de diabète de type 2, un surpoids (IMC = 28,73 Kg/m2). Une insulinothérapie a été instaurée. Le bilan étiologique de cette décompensation métabolique et la recherche de d’anticorps anti-GAD et anti-IA2 sont négatifs. Après 3 mois d’insulinothérapie, on obtient un équilibre glycémique satisfaisant marqué par une HbA1c à 7 % et un peptide C remonté à 300 pmol/l (pour une GV à 1,09g/l). Au bilan du 6 mois, le patient présente un parfait équilibre glycémique (HbA1C : 6,4 %), avec un peptide C qui s’est normalisé à 870 pmol/l (pour une GV à 1,29g/l). C’est qui a permis de proposer l’arrêt de l’insulinothérapie malheureusement récusé par le patient pour des raisons sociales. Aucune anomalie n’a été objectivée au fond de l’œil, ni à l’électro-cardiogramme, ni à l’évaluation de la fonction rénale (Clairance de créatinine normale par MDRD et micro-albuminurie négative). Ce tableau clinique illustre un cas de diabète africain. Il s’agit d’une expression clinique proche du diabète de type 1 (DT1) mais se caractérise par une rémission, plus lente que la lune de miel dans le DT1, avec une absence de stigmates d’auto-immunité. Il est considéré comme diabète atypique ou de type 1 idiopathique. Discussion /Conclusion : Ce type de diabète évoque plusieurs hypothèses physiopathologiques. L’équilibre glycémique est rapidement obtenu sous insulinothérapie, avec possibilité de réémission.   African diabetes or atypical diabetes refers to a specific type of diabetes that initially presents with the stigma of type 1 diabetes but later progresses to type 2 diabetes with the possibility of a long remission phase. We will discuss in this article, through a clinical case in a subject of African origin, the diagnostic, metabolic, physiopathological and management specificities of this type of diabetes. Patients and methods: This is a particular clinical observation of a patient of African origin living in France with atypical diabetes. Clinical case: Patient, aged 33 years, was hospitalized for diabetic ketoacidosis. He had a family history of type 2 diabetes, was overweight (BMI = 28.73 Kg/m2). Insulin therapy was initiated. The etiological assessment of this metabolic decompensation and the search for anti-GAD and anti-IA2 antibodies were negative. After 3 months of insulin therapy, a satisfactory glycemic balance was obtained, marked by an HbA1c of 7% and a C-peptide of 300 pmol/l (for a GV of 1.09 g/l). At the 6-month check-up, the patient had perfect glycemic control (HbA1C: 6.4%), with a C-peptide that had normalized to 870 pmol/l (for a GV of 1.29g/l). This was the reason for proposing the discontinuation of insulin therapy, which was unfortunately rejected by the patient for social reasons. No abnormality was observed on the fundus, electrocardiogram or renal function tests (normal creatinine clearance by MDRD and negative microalbuminuria). This clinical picture illustrates a case of African diabetes. It is a clinical expression close to type 1 diabetes (T1DM) but is characterized by a remission, slower than the honeymoon in T1DM, with an absence of autoimmune stigma. It is considered atypical or idiopathic type 1 diabetes. Discussion/Conclusion : This type of diabetes raises several pathophysiological hypotheses. Glycemic control is rapidly obtained with insulin therapy, with the possibility of re-emission

Multiparametric determination of genes and their point mutations for identification of beta-lactamases

More than half of all currently used antibiotics belong to the beta-lactam group, but their clinical effectiveness is severely limited by antibiotic resistance of microorganisms that are the causative agents of infectious diseases. Several mechanisms for the resistance of Enterobacteriaceae have been established, but the main one is the enzymatic hydrolysis of the antibiotic by specific enzymes called beta-lactamases. Beta-lactamases represent a large group of genetically and functionally different enzymes of which extended-spectrum beta-lactamases (ESBLs) pose the greatest threat. Due to the plasmid localization of the encoded genes, the distribution of these enzymes among the pathogens increases every year. Among ESBLs the most widespread and clinically relevant are class A ESBLs of TEM, SHV, and CTX-M types. TEM and SHV type ESBLs are derived from penicillinases TEM-1, TEM-2, and SHV-1 and are characterized by several single amino acid substitutions. The extended spectrum of substrate specificity for CTX-M beta-lactamases is also associated with the emergence of single mutations in the coding genes. The present review describes various molecular-biological methods used to identify determinants of antibiotic resistance. Particular attention is given to the method of hybridization analysis on microarrays, which allows simultaneous multiparametric determination of many genes and point mutations in them. A separate chapter deals with the use of hybridization analysis on microarrays for genotyping of the major clinically significant ESBLs. Specificity of mutation detection by means of hybridization analysis with different detection techniques is compared

Predicting the seasonal evolution of southern African summer precipitation in the DePreSys3 prediction system

We assess the ability of the DePreSys3 prediction system to predict austral summer precipitation (DJF) over southern Africa, defined as the African continent south of 15°S. DePresys3 is a high resolution prediction system (at a horizontal resolution of ~ 60 km in the atmosphere in mid-latitudes and of the quarter degree in the Ocean) and spans the long period 1959–2016. We find skill in predicting interannual precipitation variability, relative to a long-term trend; the anomaly correlation skill score over southern Africa is greater than 0.45 for the first summer (i.e. lead month 2–4), and 0.37 over Mozambique, Zimbabwe and Zambia for the second summer (i.e. lead month 14–16). The skill is related to the successful prediction of the El-Nino Southern Oscillation (ENSO), and the successful simulation of ENSO teleconnections to southern Africa. However, overall skill is sensitive to the inclusion of strong La-Nina events and also appears to change with forecast epoch. For example, the skill in predicting precipitation over Mozambique is significantly larger for the first summer in the 1990–2016 period, compared to the 1959–1985 period. The difference in skill in predicting interannual precipitation variability over southern Africa in different epochs is consistent with a change in the strength of the observed teleconnections of ENSO. After 1990, and consistent with the increased skill, the observed impact of ENSO appears to strengthen over west Mozambique, in association with changes in ENSO related atmospheric convergence anomalies. However, these apparent changes in teleconnections are not captured by the ensemble-mean predictions using DePreSys3. The changes in the ENSO teleconnection are consistent with a warming over the Indian Ocean and modulation of ENSO properties between the different epochs, but may also be associated with unpredictable atmospheric variability

The possible role of local air pollution in climate change in West Africa

The climate of West Africa is characterized by a sensitive monsoon system that is associated with marked natural precipitation variability. This region has been and is projected to be subject to substantial global and regional-scale changes including greenhouse-gas-induced warming and sea-level rise, land-use and land-cover change, and substantial biomass burning. We argue that more attention should be paid to rapidly increasing air pollution over the explosively growing cities of West Africa, as experiences from other regions suggest that this can alter regional climate through the influences of aerosols on clouds and radiation, and will also affect human health and food security. We need better observations and models to quantify the magnitude and characteristics of these impacts