Hierarchical Ascendant Classification Research Articles

Les systèmes agroforestiers du domaine soudanien du Togo : historique et facteurs explicatifs de la dynamique évolutive

The aim of this study is to analyse the evolutionary trajectories of these agroforestry systems in order to identify the main drivers of change that influence their resilient and sustainable management in the Sudanian zone of Togo. Specifically, the aim is to: analyse the main changes that have occurred since 1960; characterise the evolutionary trajectories; and determine the drivers of change that could help to understand the evolution of these systems. The data were collected using a retrospective and prospective diagnostic survey of a sample of farmers, including resource persons, following the Historical-Sociological Investigation Method by means of semi-structured interviews. A Principal Component Analysis coupled with an Ascending Hierarchical Classification was used to study the main stages in the development of these systems. Despite having adopted various measures to promote their adaptability, profound changes have marked the evolution of these systems, testing their limits in the face of these challenges. In this context of adaptability, the results reveal two major transition models: a ‘model of transition from indigenous agricultural systems to extensive and sustainable systems’, dominant in ecological zone I with 47.44% of the systems surveyed, and an ‘agro-ecological transition model towards sustainable, innovative and resilient systems’, dominant in ecological zone II with 52.56% of the said systems. In this duality of agroforestry system management models, it is essential to analyse the evolutionary trajectories and drivers of change in order to draw up appropriate agricultural and environmental policies, with a view to the possible transplantation of these trajectories for sustainable and resilient agriculture both within and between ecological zones.

Characterization of the agriculture-livestock-environment integration system (sia2e) in the Maradi region along the north-center-south gradient

In Niger in general and in the Maradi region in particular, the management of space and natural resources leads to problems for agricultural and livestock farms. This study was conducted in the Maradi region in order to characterize the agriculture-livestock-environment integration system at the farm level in the Maradi region along the gradient of North (Dakoro), Center (Guidan Roumdji), South (Madarounfa). The methodology used to achieve this objective consisted of surveys of 300 households in the Maradi region, which were then analysed using Hierarchical Ascending Classification (HAC) and Principal Component Analysis (PCA). The results allowed us to distinguish three groups of farm sizes. Group 1 farms are characterized by large farms with an age greater than 41 years, a total cultivated area greater than 1 ha, and a large number of livestock greater than 3 UTF. These farmers are more represented in Dakoro (57%) and Guidan Roumdji (38%) and are more involved in Agriculture-Livestock-Environment than the other groups. As for group 2 farms, they are more numerous than group 1 farms in Guidan Roumdji (49%) and Madarounfa (49%). These farms have a cultivated area > 3 ha and a number of dependents between 5 and 14 peoples. The farms in group 3 are the least old and less numerous than those in groups 1 and 2, with very low values in Dakoro. This study categorized farmers in the Maradi region into three groups according to age, field area, household size and number of animals. It shows that agriculture-livestock-environment integration is practised by all the farms surveyed, but at different levels. Finally, particular attention was paid to the contribution of this agriculture-livestock-environment integration to improving soil fertility, household income and food and nutritional security.

Contribution of agromorphological and qualitative traits to the study of the diversity of the caprifig (Ficus carica L.) in traditional agroecosystems in northern Morocco

Morocco is founded to be as one of the substantial leading fig tree producers. Caprification plays a crucial role in fig production regions as the primary factor that significantly influences both the yield and quality of fig production. Our study focuses on characterizing caprifig varieties in the Bni Ahmed region (northern Morocco) and emphasizing their phenotypic potential in the context of climate change. Using 34 agromorphological and qualitative traits (IPGRI), the study examined 40 caprifig trees belonging to four local varieties of caprifig. The varietal characterization was completed by the collecting and analyzing fruit and leaf samples in the laboratory. Qualitative traits indicated morphological variability among the varieties investigated. All quantitative parameters, except fruit skin thickness, showed significant differences. Analysis of simple correlation coefficients indicated strong relationships between the measured variables. The analysis of the simple correlation coefficients revealed strong correlations between the measured variables. A remarkable phenotypic variety was identified among the caprifig accessions studied. The principal component analysis showed that the first two components explain 60% of the total variability. Weight, fruit dimensions, neck diameter, fruit pulp thickness, number of Blastophaga, length, width, leaf area, and central lobe length contribute significantly to the total variation. Analysis of the Hierarchical Ascending Classification revealed the existence of three varieties: L’morr, l’louizi, and l’hlou. The variety L’morr has shown a very high potential in terms of fruit characters and pollinating insects. Thus, a genetic analysis can confirm the agromorphological results and breeding programs should consider these unknown genetic resources, such as the L’morr variety, to provide better quality caprifigs.

Optimized wastewater management utilizing multivariate statistical analysis: a case study of the Mascara wastewater treatment plant, Algeria.

Effective wastewater management is crucial in regions experiencing water scarcity and environmental stressors, such as pollution and climate change. Optimizing treatment processes is essential for achieving environmental sustainability. This study aims to highlight the importance of effective wastewater management strategies, particularly in regions facing water scarcity. Our objective was to identify key factors influencing the treatment process. Therefore, we evaluated associations between physicochemical parameters using multivariate statistical methods, including Principal Component Analysis (PCA) and Hierarchical Ascendant Classification (HAC). Our findings categorize the monthly water samples into three distinct groups based on levels of organic pollution: the first group (July, August, and September) is characterized by high oxygenation levels and significantly low organic pollution, indicating optimal system operation. The second group (April, October, November, and December) exhibits low oxygenation and low organic pollution, promoting sludge settling and pollutant reduction. The third group (January, February, March, May, and June) shows significantly high organic pollution and low oxygenation, which corresponds to unfavorable environmental conditions. Our study demonstrates the effectiveness of multivariate statistical methods in optimizing wastewater treatment processes, providing crucial insights for environmental sustainability and water resource management.

Spatial variability of geotechnical parameters of lateritic gravels in an Olama–Ngomedzap road section in a humid tropical area (Cameroon)

Searching for borrow pits often used during civil engineering constructions is an important step that requires a lot of time and money. The nature of the parent rock, climate, topography, vegetation and time influence the formation of lateritic gravels with different geotechnical properties within the same region. The present study aims at finding the spatial variability of geotechnical parameters of lateritic gravels from two different deposits using a variogram and statistical analysis. Out of 122 lateritic gravel samples collected, 69 were from underdeveloped lithic ferrallitic soils (LFS) and 53 from under developed non-lithic ferrallitic soils (NLFS). The mean values of the coefficient of variation (CV) shows that the geotechnical parameters of LFS-derived lateritic gravels are more dispersed than those developed on NLFS. The fines content, plasticity index (PI) and Californian bearing ratio (CBR) variograms observed mainly in the North and NNE parts of the study area, suggest that, the lateritic gravels in this area have average to good geotechnical characteristics. The principal component analysis (PCA) indicates that the CBR and the maximum dry density (MDD) are inversely related to the optimum moisture content (OMC). The discriminant factor analysis (DFA) coupled to the ascending hierarchical classification (AHC) shows three families of lateritic gravels: (1) class 1/3, lateritic gravels characterized by MDD, CBR, consistency index (CI), gravels content, and plastic limit (PL); (2) class 2/3, lateritic gravels characterized by fines content, and maximum grain diameter (Dmax) and, (3) class 3/3, lateritic gravels characterized by OMC, liquid limit (LL), PI, PL, and fines content, that fit for road construction.

Infant feeding practices and body mass index up to 7.5 years in the French nationwide ELFE study.

The infant diet represents one of the main modifiable determinants of early growth. This study aimed to investigate the associations of infant feeding practices with body mass index (BMI) until 7.5 years. Analyses were based on data from the French nationwide ELFE birth cohort. Data on breastfeeding (BF) and complementary feeding (CF) were collected monthly from 2 to 10 months. Infant feeding practices were characterized using principal component analyses (PCA) and hierarchical ascendant classification. BMI z-score was computed at 1, 2, 3, 5 and 7.5 years, from data collected in the child's health booklet; 7.5-year overweight was defined according to IOTF references. Associations between infant feeding practices and BMI were investigated by linear regression models adjusted for main confounders. Ever breastfeeding was not associated with BMI up to 7.5 years. Compared to intermediate breastfeeding duration (1 to <3 months), longer breastfeeding duration (≥6 months) was related to lower 1-year BMI, but not at older ages. Compared to the recommended age at CF introduction (4-6 months), early CF (<4 months) was related to higher BMI up to 5 years with a similar trend at 7.5 years, but not to the risk of overweight. The PCA patterns characterized by early baby cereal introduction and late food pieces introduction or by frequent intake of main food groups were related to a lower BMI up to 7.5 years. Breastfeeding was related with a lower BMI in infancy but not thereafter, whereas an early CF initiation (<4 months) was associated with a higher BMI in childhood.

Analysis of the obstetrician's posture and movements during a simulated forceps delivery

BackgroundThe objective of this study was to identify and qualify, by means of a three-dimensional kinematic analysis, the postures and movements of obstetricians during a simulated forceps birth, and then to study the association of the obstetricians’ experience with the technique adopted.MethodFifty-seven volunteer obstetricians, 20 from the Limoges and 37 from the Poitiers University hospitals, were included in this multi-centric study. They were classified into 3 groups: beginners, intermediates, and experts, beginners having performed fewer than 10 forceps deliveries in real conditions, intermediates between 10 and 100, and experts more than 100. The posture and movements of the obstetricians were recorded between December 2020 and March 2021 using an optoelectronic motion capture system during simulated forceps births. Joint angles qualifying these postures and movements were analysed between the three phases of the foetal traction. These phases were defined by the passage of a virtual point associated with the forceps blade through two anatomical planes: the mid-pelvis and the pelvic outlet. Then, a consolidated ascending hierarchical classification (AHC) was applied to these data in order to objectify the existence of groups of similar behaviours.ResultsThe AHC distinguished four different postures adopted when crossing the first plane and three different traction techniques. 48% of the beginners adopted one of the two raised posture, 22% being raised without trunk flexion and 26% raised with trunk flexion. Conversely, 58% of the experts positioned themselves in a “chevalier servant” posture (going down on one knee) and 25% in a “squatting” posture before initiating traction. The results also show that the joint movement amplitude tends to reduce with the level of expertise.ConclusionForceps delivery was performed in different ways, with the experienced obstetricians favouring postures that enabled observation at the level of the maternal perineum and techniques reducing movement amplitude. The first perspective of this work is to relate these different techniques to the traction force generated. The results of these studies have the potential to contribute to the training of obstetricians in forceps delivery, and to improve the safety of women and newborns.

Assessment and Optimization of the Insecticidal Properties of γ-Al2O3 Nanoparticles Derived from Mentha pulegium By-Products to Xylosandrus crassiusculus (Carob Beetle).

This study concentrates on assessing the insecticidal attributes of the γ-Al2O3 nanoparticles derived from the remnants of Mentha pulegium, which include essential oil, ethanolic extract, and plant waste. The synthesis of the γ-Al2O3 nanoparticles was executed using a direct sol-gel procedure, affirming the crystal structure according to extensive physicochemical analyses such as UV-Vis, XRD, FTIR, and SEM. Evaluation of the insecticidal activity in vitro was conducted against Xylosandrus crassiusculus, a pest that infests carob wood, utilizing strains from diverse forests in the Khenifra region, situated in the Moroccan Middle Atlas. The lethal doses 50 ranged from 40 mg/g to 68 mg/g, indicating moderate effectiveness compared to the commercial insecticide Permethrin. Optimization of the conditions for the efficiency of the γ-Al2O3 nanoparticles was determined using experimental plans, revealing that time, humidity, and temperature were influential factors in the lethal dose 50 of these nanomaterials. Moreover, this study encompasses the establishment of correlations using Principal Component Analysis (PCA) and Ascending Hierarchical Classification (AHC) among various geographic, biological, and physical data, amalgamating geographic altitude and γ-Al2O3 nanoparticle insecticide parameters, as well as the attributes of the mechanical tests conducted on the carob wood affected by insects. The correlations highlight the close connections between the effectiveness of the insecticide, mountain altitude, and the mechanical parameters that were examined. Ultimately, these nanoparticles demonstrate promising potential as alternative insecticides, thus opening up encouraging prospects for safeguarding against carob wood pests.

Typologie des systemes de productions du bovin de race djelli (Bos taurus indicus) dans les communes de Gotheye, Sinder et Say au Niger

The development of Djelli cattle breeding in Niger remains a challenge due to prejudices about its productivity. The particularities of its production systems have not been sufficiently developed. The aim of this study is to develop a typology of local Djelli cattle production systems in six localities in the communes of Gothèye, Sinder and Say in Niger. A survey was carried out among 150 breeders. Discriminant factor analysis (DFA) and hierarchical ascending classification (HAC) were used to identify three types of production system: The first type is made up of transhumant herders whose main activity is livestock rearing and who belong to the Peulh ethnic group. This type is characterized by large herds (27 head). They have 3 breeding cows and 4 suckling cows for 16 breeding females. The second type is made up of sedentary breeders. Their main activities are fishing and trading, and they belong to the Sonrai socio-cultural ethnic group. Their herds are modest (17 head), comprising 2 breeding and 5 suckling cows for 11 breeding females. The third type is made up of semi-transhumant herders. Their main activity is farming, and they belong to the Sonrai socio-cultural ethnic group, with an equally modest herd size (18 head). The number of breeding cows is similar to that of the sedentary herders (2 head). However, the number of sucklers is reduced to 3 head for 10 breeding females. The daily intake of bran concentrate per suckling female is the highest (5 kg of bran concentrate per day). The ratio of lactating females to females of breeding age was r =0.45 in the sedentary group, compared with r =0.30 in the semi-transhumant group and r = 0.25 in the transhumant group. The results also showed that the rearing environment is dominated by a diet of rice straw (39%) and rice bran (49%). The most frequently vaccinated disease on the farms was pasteurellosis (87.3%), and the highest deworming rate was 40%. The environment also revealed a variation in lactating females for the riparian localities of Say and Yelwani (5.4±2.6b and 6.0±2.8b respectively), which are very significantly different (P&lt;0.001) from the non-riparian localities of Koulbaga and Tassikoirey (2.9±1.2a and 2.8±1.20a respectively). In conclusion, sedentary farmers are the most productive in a food environment dominated by rice crop residues and diseases such as pasteurellosis and endoparasites. Key words : Production systems, herd size, sedentary breeders, lactating female

Assessment of surface water quality in a highly anthropised semi-arid catchment (Case of Wadi El Hatab Basin, Tunisia, North Africa)

Anthropogenic contamination of surface waters is a critical issue in urbanised catchments, especially in Mediterranean environments with scarce water resources and intermittent rivers. A combined hydro-geochemical and multivariate statistical methodology has been applied to evaluate the surface water quality of Wadi El Hatab catchment (Central Tunisia). More than half of the 28 samples collected in March 2021 exceeded WHO standards for sodium, chloride and sulphate contents. Most polluted sites are directly influenced by domestic and industrial effluents that contaminate the river for kilometers. Principal Component Analysis and Hierarchical Ascendant Classification distinguished four contamination sources: water-rock interaction, domestic wastewater, untreated industrial effluents mainly from paper mills and irrigation return. A Water Quality Index model indicated that 75% of the surface water was unsuitable for drinking purposes; while according to chemical indices such as saturation index, sodium absorption coefficient (SAR), magnesium ratio (MR) and percent sodium (%Na), 25 to 49% of samples were unsuitable for irrigation. Considering that water of Wadi El Hatab is used for vegetable irrigation, serious public health issues may arise. The investigation demonstrated that a single representative sampling campaign could be a useful way to identify contamination sources when interpreted with both statistical and geochemical tools.

TYPOLOGY OF FARMS IN THE AGROFORESTRY SYSTEM OF THE BATEKE PLATEAU IN THE DEMOCRATIC REPUBLIC OF CONGO

In order to contribute to the improvement of crop productivity in the agroforestry system of the Batéké plateau, a typology of farms was carried out in the sites of Mampu and Ibi village, pioneer sites of agroforestry activities in the Batéké plateau. Surveys were conducted from June to August 2022 on a sample of 183 farmers chosen according to their voluntary participation. Using the R Console Software, multivariate analyses by hierarchical ascending classification (HAC), using the hierarchical clustering method, were performed to determine the different types of holdings. The results revealed the existence of three types of farms on the site. With regard to the characteristics of these types of farms, the duration of fallow, the number of varieties used, the duration of use of cuttings, the number of weedings, the number of tubers per plant and the yield are the main parameters of their disparity. In terms of yield, it is 9.5 tonnes/ha, 13 tonnes/ha and 10 tonnes/ha respectively for type 1, type 2 and type 3 farms.

Estimates of Phenotypic and Genotypic Variance and Heritability in Eighty-Nine Bambara Groundnut [Vigna subterranea (L.) Verdcourt] Accessions Collected from Six Regions of Niger

The bambara groundnut [Vigna subterranea (L.) Verdc. (Fabaceae)] is a legume mainly cultivated by women, for the nutritional quality of these seeds. It is a so-called minor culture and the improvement of the plant and its popularization remains to be promoted. The objective of this present work is to evaluate the genetic variability of bambara groundnut accessions. The experiment was carried out according to a completely randomized block device with four replications. Twenty-two (22) characters including four (4) phenological, four (4) morphological and fourteen (14) related to yield were evaluated for accessions characterization. Descriptive analysis showed significant differences. The coefficients of variation ranged from 3.51% (maturity date) to 38.87% (shell weight). Significantly high values (CV˃20%) for 8 of the metric parameters were observed. Pod weight per plant and seed weight per plant (r=0.943), yield in kg/ha (r=0.943); seed weight per plant and yield in kg/ha (r=0.999) showed the strongest correlations. The phenotypic and genotypic coefficients of variation were high for dry biomass weight (PCV=42.23%; GCV=28.40%), shell weight (PCV=63.46%; GCV=22.46%) and 100-seed weight (PCV=25.57%; GCV=25.25%). Maturity date (95.77%) and 100-seed weight (99.84%) had high heritabilities. Broad-sense heritability and genetic gain are high for 100-seed weight (H2=99.84%; GA=52.58%). The Ascending hierarchical classification produced four groups of which group 4 is the most efficient in yield with short (20.58cm) early accessions (80.32 days). Groups 1 and 2 include, late accessions (~22cm) with respectively maturity dates (DM=85.67 days and DM=86.53 days.

An intelligent instantaneous selective method, through compacted ZnO nanoparticle pellets, based on the concept of a virtual electronic nose, for different volatile organic compounds

This paper exercises a novel procedure with virtual e-nose (VEN) systems using a single compacted nanoparticle ZnO chemical sensor. The pellets are formed by a nano-powders synthesized via a simple sol–gel method. Furthermore, in this paper task we show the transient differences in the dynamic response curves for ZnO pellet when exposed to volatile organic compounds (VOCs) namely ethanol, methanol, isopropanol, acetone and toluene. VOCs are categorized using the transient response of a single sensor at four different operating temperatures, offering diverse features that came from the reaction mechanism of the target molecule. The relevant attributes of responses were run through Ascending Hierarchical Classification integrated with Principal Component Analysis. Three clusters classified for three specific features subsets were distinguished. A new mathematical iteration of this hybrid process was performed and leads to good HAC output stability. The result is delivered automatically with three-digit sorts in a specified order after thorough implementation.

Evaluating a Public Health Information Service According to Users' Socioeconomic Position and Health Status: Protocol for a Cross-Sectional Study.

The increasing use of information technology in the field of health is supposed to promote users' empowerment but can also reinforce social inequalities. Some health authorities in various countries have developed mechanisms to offer accurate and relevant information to health care system users, often through health websites. However, the evaluation of these sociotechnical tools is inadequate, particularly with respect to differences and inequalities in use by social groups. Our study aims to evaluate the access, understanding, appraisal, and use of the French website Santé.fr by users according to their socioeconomic position and perceived health status. This cross-sectional study involves the entire French population to which Santé.fr is offered. Data will be collected through mixed methods, including a web-based questionnaire for quantitative data and interviews and focus groups for qualitative data. Collected data will cover users' access, understanding, appraisal, and use of Santé.fr, as well as sociodemographic and socioeconomic characteristics, health status, and digital health literacy. A validation of the dimensions of access, understanding, appraisal, and use of Santé.fr will be conducted, followed by principal component analysis and ascendant hierarchical classification based on the 2 main components of principal component analysis to characterize homogeneous users' profiles. Regression models will be used to investigate the relationships between each dimension and socioeconomic position and health status variables. NVivo 11 software (Lumivero) will be used to categorize interviewees' comments into preidentified themes or themes emerging from the discourse and compare them with the comments of various types of interviewees to understand the factors influencing people's access, understanding, appraisal, and use of Santé.fr. Recruitment is scheduled to begin in January 2024 and will conclude when the required number of participants is reached. Data collection is expected to be finalized approximately 7 months after recruitment, with the final data analysis programmed to be completed around December 2024. This study would be the first in France and in Europe to evaluate a public health information service, in this case the Santé.fr website (the official website of the French Ministry of Health), according to users' socioeconomic position and health status. The study could discover issues related to inequalities in access to, and the use of, digital technologies for obtaining health information on the internet. Given that access to health information on the internet is crucial for health decision-making and empowerment, inequalities in access may have subsequent consequences on health inequalities among social categories. Therefore, it is important to ensure that all social categories have access to Santé.fr. PRR1-10.2196/51123.

Typology of dairy camel farms in the Ouargla region

This research aims to analyze the camel production systems in the Ouargla region of the Algerian Sahara. Questionnaires were used to collect data from 70 camel farmers, focusing on aspects like the breeders' socioeconomic status, herd structure and composition, breeding management, and the products and income derived from dromedaries. Through the application of multiple correspondence factorial analysis (MCA), principal correspondence analysis (PCA) and hierarchical ascendant classification (HAC), a typology was established. The findings revealed that meat production farming was predominant, while dairy camel farming systems demonstrated substantial economic and social significance. They are an agro-pastoral output and may therefore be a model for sustainable dairy camel farming, especially in arid regions.

Studies of the Chemical Reactivity of a Series of Benzimidazolyl-Chalcone by Quantum Chemical Approaches

This theoretical chemical reactivity study was conducted using the Density Functional Theory (DFT) method at the B3LYP/6-311G(d,p) level of calculation. It involved a series of five (05) Benzimidazolyl-Chalcone (BZC) and allowed the prediction of the chemical reactivity of these compounds. The DFT global chemical reactivity descriptors (HOMO and LUMO energies, chemical hardness, energy, electronic chemical potential and electrophilicity) were examined to predict the relative stability and reactivity of BZCs. Thus BZC-4 which has a boundary orbital energy gap of ΔEgap = 3.650 eV is the most polarisable, most reactive, good nucleophile.and it is a soft molecule. The values of the global reactivity descriptors confirmed the high chemical reactivity of BZC-4. Local reactivity indices as well as dual descriptors were calculated to indicate the likely sites of electrophilic and nucleophilic attack of the different compounds studied. The analysis of the local indices and the dual descriptors revealed that the nitrogen heteroatom N13 is the preferential site of electrophilic attack and the carbon atom C1 should be the most reactive site with respect to a nucleophilic attack. the Hierarchical Ascending Classification analysis allowed us to group all five (5) compounds studied into three categories. The most active which are BZC-1 and BZC-5, the moderately active BZC-2, and the compounds BZC-3 and BZC-4, the least active. Moreover, this classification is consistent with the value of the Larvicide concentrations (LC100 (μg/mL)).&#x0D; Keywords : Benzimidazolyl-Chalcone (BZC), Global descriptors, Local descriptors, Dual descriptors

Classification of bottled waters marketed and consumed in Algeria through statistical approaches.

The main objective of this work consists of classifying 30 brands of water bottled and marketed in Algeria, based on their physicochemical compositions and their comparison with some foreign brands recognized in their countries or on a world scale. Relevant to this, descriptive statistics, as well as hierarchical ascendant classification (HAC) and principal component analysis (PCA), were used to analyse the data. The results of this study highlighted a similarity between some Algerian brands and other foreign brands of water in terms of mineral content. Moreover, the results obtained by using PCA and HAC allowed us to divide the sample of Algerian mineral waters into three distinct groups, each with similar physicochemical characteristics. The first group (Soummam, Manbaa Al Ghezlane, Mouzaia, Amane, Djmila, and Hayet) is characterized by very high levels of mineral salts compared to the other brands. The second group (Guedila, Tazliza, Arwa, Baniane, Saida, Ifri, Messerghine, Sfid, Mansourah, Batna, Mileza, S. Rached, Dhaya, Qniaa, and Lejdar) is distinguished from the first group by its average mineralization. Finally, the third group (Fezguia, Nestlé, Ovitale, L. Khedidja, A. Bouglez, Ayris, Righia, Togi, and Toudja) presents a very low mineralization.

Drivers of the dynamics of the spread of cholera in the Democratic Republic of the Congo, 2000-2018: An eco-epidemiological study.

The dynamics of the spread of cholera epidemics in the Democratic Republic of the Congo (DRC), from east to west and within western DRC, have been extensively studied. However, the drivers of these spread processes remain unclear. We therefore sought to better understand the factors associated with these spread dynamics and their potential underlying mechanisms. In this eco-epidemiological study, we focused on the spread processes of cholera epidemics originating from the shores of Lake Kivu, involving the areas bordering Lake Kivu, the areas surrounding the lake areas, and the areas out of endemic eastern DRC (eastern and western non-endemic provinces). Over the period 2000-2018, we collected data on suspected cholera cases, and a set of several variables including types of conflicts, the number of internally displaced persons (IDPs), population density, transportation network density, and accessibility indicators. Using multivariate ordinal logistic regression models, we identified factors associated with the spread of cholera outside the endemic eastern DRC. We performed multivariate Vector Auto Regressive models to analyze potential underlying mechanisms involving the factors associated with these spread dynamics. Finally, we classified the affected health zones using hierarchical ascendant classification based on principal component analysis (PCA). The increase in the number of suspected cholera cases, the exacerbation of conflict events, and the number of IDPs in eastern endemic areas were associated with an increased risk of cholera spreading outside the endemic eastern provinces. We found that the increase in suspected cholera cases was influenced by the increase in battles at lag of 4 weeks, which were influenced by the violence against civilians with a 1-week lag. The violent conflict events influenced the increase in the number of IDPs 4 to 6 weeks later. Other influences and uni- or bidirectional causal links were observed between violent and non-violent conflicts, and between conflicts and IDPs. Hierarchical clustering on PCA identified three categories of affected health zones: densely populated urban areas with few but large and longer epidemics; moderately and accessible areas with more but small epidemics; less populated and less accessible areas with more and larger epidemics. Our findings argue for monitoring conflict dynamics to predict the risk of geographic expansion of cholera in the DRC. They also suggest areas where interventions should be appropriately focused to build their resilience to the disease.

Typology of Health Districts Based on Data from Ten Infectious Diseases Under Surveillance in Senegal

The aim of this work is to construct a typology of health districts in Senegal based on the distribution frequency of ten infectious diseases under surveillance. Our methodology utilizes HCPC (Hierarchical Classification on Principal Components) algorithm which combines two data analysis techniques, namely Principal Component Analysis (PCA) and Hierarchical Ascending Classification (HAC). The data come from the Prevention Department of the Ministry of Health and Social Action and cover the period from January 2018 to November 2022. The results show that health districts in Senegal can be divided into three clusters according to the number of confirmed cases recorded for each of the ten considered infectious diseases. Moreover, the parangons’ principle allows us to select from the obtained clusters a representative stratified sample of health districts in view to identifying risk factors associated with these ten pathologies.

A new method to assess sustainability of agricultural systems by integrating ecosystem services and environmental impacts

Agricultural stakeholders disagree on how to put the general concept of sustainability into practice. But most recognize the need for assessment methods to characterize the current situation and gauge progress yet to be made. Many sustainability assessment methods for agricultural systems have been published, but very few integrate ecosystem services (ES). And yet, ES indicators are key to better integrating biological processes to support the agroecological transition. Although researchers have attempted to link the concept of environmental impact (EI) and ES through life cycle analysis (LCA), gaps remain when it comes to doing so within a sustainability assessment method. Here a new method based on an original conceptual indicator framework embedding new predictive indicators of EI and ES indicators was developed. This framework covers 22 environmental themes and integrates few basic economic and social indicators. The method was implemented on 33 farms with different certifications and production specifications. All farms were members of an agricultural cooperative in north-eastern France. We selected 250 plots to cover the farms’ crop rotations. The correlation analysis showed no systemic trade-off between EI or ES and economic indicators. Meanwhile, the joint assessment of ES and EI (like the multivariate analysis), delivered more nuanced results than a classical opposition between intensive and organic farming. Some farms with a moderate or even good level of ES often do not leverage them, as shown by their high EI. The principle component analysis and subsequent hierarchical ascendant classification allowed us to distinguish five clusters providing a more complex picture than simply opposing conventional and organic agriculture. Finally, the positive deviance analysis revealed that economic, environmental and social considerations can be balanced in a way that seems to be more sustainable than, for example, an organic farm that has very successfully reduced EI but at a cost of several economic and social trade-offs.