231 research outputs found

    Kernel-based measures of association between inputs and outputs based on ANOVA

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    ANOVA decomposition of function with random input variables provides ANOVA functionals (AFs), which contain information about the contributions of the input variables on the output variable(s). By embedding AFs into an appropriate reproducing kernel Hilbert space regarding their distributions, we propose an efficient statistical test of independence between the input variables and output variable(s). The resulting test statistic leads to new dependent measures of association between inputs and outputs that allow for i) dealing with any distribution of AFs, including the Cauchy distribution, ii) accounting for the necessary or desirable moments of AFs and the interactions among the input variables. In uncertainty quantification for mathematical models, a number of existing measures are special cases of this framework. We then provide unified and general global sensitivity indices and their consistent estimators, including asymptotic distributions. For Gaussian-distributed AFs, we obtain Sobol' indices and dependent generalized sensitivity indices using quadratic kernels

    Derivative-based global sensitivity measures: general links with Sobol' indices and numerical tests

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    The estimation of variance-based importance measures (called Sobol' indices) of the input variables of a numerical model can require a large number of model evaluations. It turns to be unacceptable for high-dimensional model involving a large number of input variables (typically more than ten). Recently, Sobol and Kucherenko have proposed the Derivative-based Global Sensitivity Measures (DGSM), defined as the integral of the squared derivatives of the model output, showing that it can help to solve the problem of dimensionality in some cases. We provide a general inequality link between DGSM and total Sobol' indices for input variables belonging to the class of Boltzmann probability measures, thus extending the previous results of Sobol and Kucherenko for uniform and normal measures. The special case of log-concave measures is also described. This link provides a DGSM-based maximal bound for the total Sobol indices. Numerical tests show the performance of the bound and its usefulness in practice

    DĂ©terminants des migrations de l’Afrique vers l’Europe : du court sĂ©jour Ă  la migration durable et / ou irrĂ©guliĂšre

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    International migration is often seen as a single, one-way movement from a country of origin to a host country. In contrast to this unidirectional view of migration, this thesis focuses on the articulation between temporary and long-term migration in the context of migration between Africa and Europe. More specifically, it focuses on the individual and contextual factors that explain why movements supposedly limited in time (called temporary) are transformed into long stays. In this research, temporary travel is approached from two perspectives: duration and law. In one case [1st empirical article], the aim is to study to what extent and for what reasons occasional stays (lasting less than one year) become the precursors of a sustainable settlement in Europe (for a period of at least one year). In the other case [2nd and 3rd empirical articles], the aim is to study how and why stays designed as temporary from a legal point of view (cases where migrants have a non-permanent right of residence) are transformed into irregular long-term stays. The thesis adopts a comparative approach that focuses on contextual effects in both three African countries of origin (Democratic Republic of Congo, Ghana and Senegal) and six European countries of destination (Belgium, United Kingdom, Netherlands, France, Italy and Spain), with a particular focus on migration policy changes. It draws on three international databases: on the one hand, the individual biographical data of the MAFE project (Migrations between Africa and Europe) and, on the other hand, two contextual databases containing a coded description of migration policy changes of the "Immigration Policy" and "Temporary vs permanent migration" projects, and the "Determinants of International Migration: A Theoretical and Empirical Assessment of Policy, Origin and Destination Effects" (DEMIG) project. The statistical methods used are, on the one hand, descriptive statistics, in particular Kaplan-Meier curves and bivariate analysis methods and, on the other hand, explanatory models, in particular discrete time risk and duration models and the logit model. In the first article, it appears that short-term stay has a positive effect on long-term migration for the three sub-Saharan flows considered, although this effect is much greater for Congolese than for Ghanaians and Senegalese. The effect of short stay migration also depends on the period for Congolese migrants, while this interaction is not significant for Senegalese migrants and Ghanaian migrants, which indicates not only the context of the country of origin modulates the effect of the short stay on sustainable migration, but also the variation of the context over time within the same country of origin can modify the relationship between short stay and long term migration. In addition, it is noted that the level of education, land and house ownership, unemployment in the country of origin, social networks and studies in Europe seem to favour the relationship between short and long stays, but economic activity and employment in the countries of origin seem to have the opposite effect. The second article revealed that the risk of being in an irregular situation was increased in periods when migration policies were becoming increasingly strict. The influence of the entry period is very clear for Ghanaian and Senegalese migrants, but the risk of being in an irregular situation decreased in the 1990s and 2000s among Congolese migrants, suggesting that migrants from a country in conflict benefit from some protection against irregularity. The risk of being in an irregular situation is higher in recent immigration countries (Italy and Spain) than in traditional immigration countries (France and the United Kingdom). The irregularity also depends on the individual characteristics and circumstances of departure for Europe. The third article unexpectedly revealed that only policies aimed at limiting entry appear to have a significant effect on the transition to irregularity of Senegalese migrants already legally entering France, Italy and Spain. This result suggests that when policies to control entry become more stringent, migrants no longer dare to leave for fear of not being able to return. Other contextual elements also influence the irregularity of migrants: a negative effect of Senegal's annual GDP growth on the transition to irregularity (immigrants would choose to return to the country to work, thus avoiding irregularity), but a positive effect of the host country's annual GDP growth on the transition to irregularity (they would remain there to benefit from growth despite irregularity).La migration internationale est souvent considĂ©rĂ©e comme un mouvement unique et unidirectionnel d’un pays d’origine vers un pays d’accueil. À l’encontre de cette vision unidirectionnelle des migrations, cette thĂšse s’intĂ©resse Ă  l’articulation entre les migrations temporaires et celles de longues durĂ©es, dans le contexte des migrations entre l’Afrique et l’Europe. Plus spĂ©cifiquement, elle s’intĂ©resse aux facteurs, individuels et contextuels, qui expliquent que des dĂ©placements supposĂ©s limitĂ©s dans le temps (dits temporaires) se transforment en sĂ©jours de longues durĂ©es. Dans cette recherche, les dĂ©placements temporaires sont abordĂ©s de deux points de vue : celui de la durĂ©e et celui du droit. Dans un cas [1er article empirique], il s’agit d’étudier dans quelle mesure et pour quelles raisons des sĂ©jours ponctuels (d’une durĂ©e infĂ©rieure Ă  un an) deviennent les prĂ©curseurs d’une installation durable en Europe (pour une durĂ©e d’un an au moins). Dans l’autre cas [2Ăšme et 3Ăšme articles empiriques], il s’agit d’étudier comment et pourquoi des sĂ©jours conçus comme temporaires du point de vue lĂ©gal (cas oĂč les migrants ont un droit de sĂ©jour non permanent) se transforment en sĂ©jours durables irrĂ©guliers. La thĂšse adopte une approche comparative qui permet de s’intĂ©resser aux effets de contexte Ă  la fois dans trois pays africains d’origine (RĂ©publique DĂ©mocratique du Congo, Ghana et SĂ©nĂ©gal) et dans six pays europĂ©ens de destination (Belgique, Royaume-Uni, Pays-Bas, France, Italie et Espagne), avec une attention particuliĂšre pour les changements de politiques migratoires. Elle tire parti de trois bases de donnĂ©es internationales : d’une part, les donnĂ©es biographiques individuelles du projet MAFE (Migrations entre l’Afrique et l’Europe) et, d’autre part, de deux bases de donnĂ©es contextuelles qui contiennent une description codĂ©e des changements de politiques migratoires des projets « Immigration Policy » et « Temporary vs permanent migration », et du projet « Determinants of International Migration : A Theoretical and Empirical Assessment of Policy, Origin and Destination Effects » (DEMIG). Les mĂ©thodes statistiques utilisĂ©es sont, d’une part, les statistiques descriptives, notamment les courbes de Kaplan-Meier et les mĂ©thodes d’analyses bivariĂ©es et, d’autre part, les modĂšles explicatifs, en particulier les modĂšles de risque et de durĂ©e en temps discrets et le modĂšle logit. Dans le premier article, il ressort que le sĂ©jour de courte durĂ©e a un effet positif sur la migration de longue durĂ©e pour les trois flux subsahariens considĂ©rĂ©s, bien que cet effet soit beaucoup plus important pour les Congolais que les GhanĂ©ens et les SĂ©nĂ©galais. L’effet d’une migration de court sĂ©jour dĂ©pend par ailleurs de la pĂ©riode pour les migrants congolais, alors que cette interaction n’est pas significative pour les migrants sĂ©nĂ©galais et les migrants ghanĂ©ens, ce qui indique non seulement le contexte du pays d’origine module l’effet du court sĂ©jour sur la migration durable, mais aussi la variation du contexte dans le temps au sein d’un mĂȘme pays d’origine peut modifier la relation entre le sĂ©jour de courte durĂ©e et la migration de longue durĂ©e. En outre, on note que le niveau d’éducation, la possession de terrain et de maison, le chĂŽmage dans le pays d’origine, les rĂ©seaux sociaux et les Ă©tudes en Europe semblent favoriser la relation entre les sĂ©jours court et long, mais l’activitĂ© Ă©conomique et l’emploi dans les pays d’origine semblent avoir un effet contraire. Le deuxiĂšme article a rĂ©vĂ©lĂ© que le risque d’ĂȘtre en situation irrĂ©guliĂšre Ă©tait accru dans les pĂ©riodes oĂč les politiques migratoires devenaient de plus en plus strictes. L’influence de la pĂ©riode d’entrĂ©e est trĂšs claire pour les migrants ghanĂ©ens et sĂ©nĂ©galais, mais le risque d’ĂȘtre en situation irrĂ©guliĂšre a diminuĂ© dans les annĂ©es 1990 et les annĂ©es 2000 chez les migrants congolais, ce qui semble indiquer que les migrants issus d’un pays en conflit bĂ©nĂ©ficient d’une certaine protection face Ă  l’irrĂ©gularitĂ©. Le risque d’ĂȘtre en situation irrĂ©guliĂšre est plus Ă©levĂ© dans les pays d’immigration rĂ©cents (l’Italie et l’Espagne) que dans les pays d’immigration traditionnels (France et Royaume-Uni). L’irrĂ©gularitĂ© dĂ©pend Ă©galement des caractĂ©ristiques individuelles et des circonstances de dĂ©part pour l’Europe. Le troisiĂšme article a rĂ©vĂ©lĂ©, de maniĂšre inattendue, que seules les politiques destinĂ©es Ă  limiter les entrĂ©es semblent avoir un effet significatif sur la transition vers l’irrĂ©gularitĂ© des migrants sĂ©nĂ©galais dĂ©jĂ  entrĂ©s lĂ©galement en France, en Italie et en Espagne. Ce rĂ©sultat suggĂšre que lorsque les politiques visant Ă  contrĂŽler les entrĂ©es se durcissent, les migrants n’osent plus sortir par peur de ne plus ĂȘtre capables de rentrer Ă  nouveau. D’autres Ă©lĂ©ments contextuels influencent aussi l’irrĂ©gularitĂ© des migrants : un effet nĂ©gatif de la croissance annuelle du PIB du SĂ©nĂ©gal sur la transition vers l’irrĂ©gularitĂ© (les immigrants choisiraient de retourner au pays pour y travailler, Ă©vitant ainsi l’irrĂ©gularitĂ©), mais un effet positif de la croissance annuelle du PIB du pays d’accueil sur la transition vers l’irrĂ©gularitĂ© (ils y resteraient pour profiter de la croissance malgrĂ© l’irrĂ©gularitĂ©)

    Epidemiology of Use of a Traditional Spirit “Sodabi” in the General Population of Togo

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    The purpose of this paper is to evaluate the profile of sodabi consumption in the Togolese population. This transverse descriptive study was conducted over a nine month period from June 9, 2013 to March 9, 2014, throughout the five regions of Togo. Findings demonstrated a clear profile of 2388 sodabi drinkers. 1672 (70.02%) men and 716 (29.98%) women. Prevalence was 62.45% in the population studied. Mean age was 35.3 years. Almost all subjects interrogated (98.48%) were togolese nationals. The study included the following ethnic and regional groups, the KabyÚ-Tem ethnic group (43.59%) and the Paragourma-Akan groups (23.50%) were the most represented among the subjects interrogated. More than a third (25.67%) of subjects interviewed was unemployed with a higher unemployment rate in the Maritime region and Lomé Commune (37.16%). Most of the people interrogated (49.66%) were living as couples (married or cohabiting). 4.06% of subjects drank sodabi only. 51.40% of drinkers abused sodabi (40.59% men against 10.81% women). The prevalence of noxious alcohol use was high (12.35%) among unemployed participants. 25.51% of drinkers visited drinking establishments once a week and 22.10% almost every day. The euphoric effect of alcohol (45.23%) and friendly atmosphere (19.39%) of the drinking establishment were the main reasons for attendance (64.62%). Of the damage caused by the abuse of sodabi, 39.26% of subjects showed somatic or neurological complications and 60.74% psychological and psychiatric complications. Updating these data seems necessary, because combating excessive drinking is one of the main objectives of current togolese public health policy

    Effects of food flavour enhancer (Monosodium Glutamate and Maggi Poulet) supplementation on glucose tolerance in Sprague Dawley rat

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    This study was designed to evaluate the effects of purified monosodium glutamate and ‘Maggi Poulet’, on body weight gain, lipid profile, hepatic lipid peroxidation and glucose tolerance in rats. Thirty five young male Sprague Dawley rats were divided into five groups and fed by oral route as follow: group I (distilled water), group II (monosodium glutamate solution), group III (‘Maggi Poulet’solution), group IV (monosodium glutamate solution. and high fat solution) and group V (‘Maggi Poulet’ solution and high fat solution). During the experimental period, fasting glycemia was taken and an oral glucose tolerance test has been performed at the end . Blood samples were then collected in all groups and serum cholesterol and triglyceride were assayed. Animals were killed after and abdominal adipose tissue, liver and heart were excised and weighed. Liver samples were also used to estimate hepatic malondialdehyde level in rats. The results proved that the dietary feeding did not affect the body gain and lipid profile in experimental groups. The hepatic lipid peroxidation has also increased in all experimental groups and at the same time, rats in group II, group IV and group V present a two-hour plasma glucose level signifantly higher. However, purified monosodium glutamate and ‘Maggi Poulet’ at the dose of 1500 mg/kg. b. wt. have not impaired fasting glycemia in Sprague Dawley rat. All changes observed in the glycemia of rats in experimental groups do not allow to qualify them to be glucose intolerant, nevertheless monosodium glutamate consumption in association or not with high fat is hepatotoxic and may contribute to the emergence of prediabetes in human being. © 2013 International Formulae Group. All rights reserved.Keywords: Malondialdehyde, lipid profile, glucose homeostasis, prediabetes

    Prévalence du pré-diabÚte, du syndrome métabolique, du diabÚte et des dyslipidémies chez 350 sujets recrutés au marché de Hédzranawoé à Lomé (Togo)

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    Les sujets atteints de prĂ©-diabĂšte prĂ©sentent un risque Ă©levĂ© de syndrome mĂ©tabolique (SM) et de diabĂšte. La prĂ©sente Ă©tude avait pour but d’évaluer la prĂ©valence du prĂ©-diabĂšte, du SM et du diabĂšte dans une population frĂ©quentant un marchĂ© urbain, puis de dĂ©terminer la prĂ©valence des dyslipidĂ©mies chez les prĂ©-diabĂ©tiques et diabĂ©tiques. Il s’est agi d’une Ă©tude transversale Ă  visĂ©e descriptive portant sur 350 sujets ĂągĂ©s de 18 Ă  90 ans, recrutĂ©s au grand marchĂ© de HĂ©dranawoĂš en 2015. La prĂ©valence du prĂ©-diabĂšte a Ă©tĂ© Ă©valuĂ©e suivant les critĂšres de l’Organisation Mondiale de la SantĂ© (OMS) et de l’American Diabetes Association (ADA). La prĂ©valence du SM a Ă©tĂ© obtenue avec les critĂšres de la FĂ©dĂ©ration Internationale du DiabĂšte (FID). La prĂ©valence du prĂ©-diabĂšte suivant le critĂšre d’ADA Ă©tait de 13,2% avec une glycĂ©mie moyenne Ă  5,9±0,3 mmol/l. Celle du SM Ă©tait de 1,3% chez les femmes et de 0,8% chez hommes, avec celle du diabĂšte qui Ă©tait Ă  7,1%. Celle des dyslipidĂ©mies variait de 32,0 Ă  60,0% chez les diabĂ©tiques dont 40% n’était pas prĂ©alablement dĂ©pistĂ©s. La prĂ©valence du diabĂšte Ă©tait plus importante que celle dĂ©terminĂ©e dans la population gĂ©nĂ©rale du Togo. La prĂ©valence du syndrome mĂ©tabolique mĂ©riterait d’ĂȘtre rĂ©Ă©valuer en utilisant des critĂšres de tour de taille Ă©tablis pour des africains au Sud du Sahara. Les populations frĂ©quentant les marchĂ©s urbains devraient ĂȘtre rĂ©guliĂšrement sensibilisĂ©es sur les risques du prĂ©-diabĂšte, du diabĂšte et des dyslipidĂ©mies.  Mots clĂ©s: HyperglycĂ©mie, urbain, adultes, hypertriglycĂ©ridĂ©mie, Togo.   English Title: Prevalence of pre-diabetes, metabolic syndrome, diabetes and dyslipidemia in 350 subjects recruited at the HĂ©dzranawoĂ© market in LomĂ© (Togo) People with pre-diabetes are at high risk for metabolic syndrome (MS) and diabetes. The purpose of the present study was to assess the prevalence of pre-diabetes, MS and diabetes in a population frequenting an urban market, and then to determine the prevalence of dyslipidemia in pre-diabetics and diabetics. This was a descriptive cross-sectional study on 350 subjects aged 18 to 90, recruited from the large market of HĂ©dranawoĂš in 2015. The prevalence of pre-diabetes was assessed according to the criteria of the World Organization of Health (WHO) and the American Diabetes Association (ADA). The prevalence of MS was obtained using the criteria of the International Diabetes Federation (IDF). The prevalence of pre-diabetes according to the ADA criterion was 13.2% with an average blood sugar level of 5.9 ± 0.3 mmol / L. That for MS was 1.3% in women and 0.8% in men, with that of diabetes at 7.1%. That of dyslipidemia ranged from 32.0 to 60.0% in diabetics. Forty percent (40%) of these diabetics were not previously screened. The prevalence of diabetes was higher than that determined in the general population of Togo. The prevalence of metabolic syndrome should be reassessed using waist size criteria established for Africans from south of the Sahara. Populations frequenting urban markets should be regularly made aware of the risks of pre-diabetes, diabetes and dyslipidemia. © 2020 International Formulae Group. All rights reserved. Keywords: Hyperglycemia, urban, adults, hypertriglyceridemia, Togo

    Genetica Forense, attualitĂ  di una risorsa

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    The large number of successful investigations ensured by the new capabilities of forensic genetics, had been followed whit great media attention,particularly since the early nineties; as a result, the role and potentialities of this subject often were distorted or misunderstood. Specifically, in the recent years, the general public, and not only, have started to assume that genetically-based personal identification techniques could be considered a sufficient and also necessary device in order to collect all the elements and evidences needed to solve a case. Through the reconstruction and analysis of three specific cases (Carretta, Bilancia and Novi Ligure) that were solved making use of genetic identification systems, the authorstry to propose a less sensational,but more likely and balanced evaluation of forensic genetics potentialities in its applications to the field of criminology. Infact, an accurate analysis of the general investigative context the contribution of forensic genetics is integrated in,on the one hand allows to remark the importance and indispensability of  traditional investigative methodologies, and, on the other hand, to point out certain forensic genetics application limits, from both a practical and theoretical point of view. Therefore, in the article the authors question the hypothesis according to which the introduction of the genetic test implies a revolution in the investigative methodologies. On the contrary they do state that the introduction of genetic analysis techniques of evidences simply has to be considered as the acquisition of a new and effective device that is meant to support and integrate the traditional ones, and not to replace themAl crescente numero di successi investigativi garantiti dall’inedito contributo della genetica forense, ha fatto riscontro, soprattutto a partire dagli anni novanta, un’enorme risonanza mediatica, il cui effetto, almeno presso il grande pubblico, ma non solo, Ăš stato quello di favorire l’affermarsi di una valutazione distorta e fuorviante del ruolo e delle potenzialitĂ  di questa disciplina nelle sue applicazioni al campo dell’indagine criminologica.In particolar modo ad imporsi Ăš stata l’idea per la quale le tecniche di identificazione personale su base genetica possano considerarsi uno strumento non solo sufficiente, ma  anche necessario, ai fini dell’acquisizione degli elementi e dei riscontri probatori investigativamente e processualmente imprescindibili per la risoluzione di un’indagine. Attraverso la ricostruzione ed analisi dei casi Carretta, Bilancia e Novi Ligure, in cui pure il ricorso alla prova genetica si Ăš rivelato probatoriamente decisivo, gli autori si propongono l’obiettivo di offrire una valutazione meno sensazionalistica, ma certo piĂč verosimile ed equilibrata, del contributo che la genetica forense offre ed Ăš in grado di offrire all’indagine criminologica. Un’analisi accurata del contesto investigativo generale nel cui ambito si inserisce l’apporto delle tecniche della genetica forense consente infatti, da un lato, di rimarcare l’imprescindibilitĂ  ed irrinunciabilitĂ  del ruolo svolto dalle metodologie di indagine tradizionali, e dall’altro, di evidenziare alcuni dei limiti, sia pratici che teorici, di applicazione del test genetico. Nell’articolo gli autori contestano dunque l’ipotesi per la quale l’introduzione del test genetico possa configurare una rivoluzione delle metodologie investigative e ribadiscono piuttosto come l’applicazione delle tecniche di analisi genetica dei reperti al campo forense vada considerata come la semplice acquisizione di un nuovo e potente strumento in grado di affiancare ed integrare efficacemente, ma non certo sostituire, quelli tradizionali, e tutt’ora essenziali, della valutazione criminologica

    Development of key processes along the supply chain by implementing the ISO 22000 standard

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    The aim of the article is to answer the question of whether the implementation of the requirements of the ISO 22000 standard in the food supply chain can support the implementation of key processes occurring in them, and thus increase the level of food quality and minimize its waste. The research was conducted out among several European countries, and an attempt was carried out to compare how the standard is perceived by entrepreneurs operating in Poland, Slovakia (Central and Eastern Europe), and Portugal (Western Europe). Covering the Polish, Slovak, and Portuguese organizations with the research process resulted from the fact that in recent years in these countries, an increase in the diversity of food demand and fragmentation of the food market has been observed. This forced food supply chains to be strictly focused on increasing the efficiency and effectiveness of production and distribution systems, as well as taking into account customer requirements and the implementation of sustainable solutions. Based on the results of the research, it can be concluded that the implementation of the requirements of the ISO 22000 standard along food supply chains can positively affect the implementation of key processes and thus contribute to reducing food waste at each stage of the supply chain.This research was supported by grant VEGA 0663/18 Requirements non-linearity and its integrationinto quality management proces

    Effect of Dietary Intake of Fermented Seeds of Parkia biglobosa (Jacq) Benth (African Locust Bean) on Hypertension in Bogou and Goumou-kope Areas of Togo

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    Purpose: To identify the possible effect of the consumption of fermented seeds of Parkia biglobosa (Jack) Benth, Mimosaceae (African locust bean) by humans on the prevention of hypertension.Methods: Two types of populations in Togo were identified and compared: one type was in a region (Bogou) where the condiment (Parkia biglobosa seeds) is highly consumed and the other people do not eat it at all (Goumou-kope). Anthropometrical, clinical and biochemical analyses were investigated in both target groups.Results: Significantly decreased blood pressure and heart beat were detected in the group of people living in Bogou’s region when compared to the non-consumption group of Goumou-kope (p < 0.001). Magnesium level was significantly increased in the Bogou group compared to that in the second group (p < 0.0001). Lower levels of low density lipoprotein-cholesterol (91± 36 vs. 110 ± 44 mg/dL, p = 0.01), triglycerides (111 ± 6 vs. 129 ± 6 mg/dL, p = 0.028), and higher levels of high density lipoproteincholesterol (63 ± 2 vs. 48 ± 3 mg/dL, p < 0.001) were observed in subjects who regularly consummed P. biglobosa fermented seeds. Furthermore, plasma glucose concentration was significantly lower in Bogou group than in Goumou-kope (68 ± 16 vs. 76 ± 15 mg/dL (p < 0.001).Conclusion: The results of the present study demonstrate that fermented seeds of Parkia biglobosa exert an anti-hypertension effect.Keywords: Blood minerals, Plasma lipids, Antihypertensive, Parkia biglobosa seed
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