Hierarchical Ascendant Classification Research Articles

Cattle keepers’ perception on the most important infectious diseases that limit milk production in Benin and municipalities at higher risks

In Benin herders are confronted with a number of infectious diseases whose epidemiology remains unclear. The objective of the present study was to assess cattle keepers’ perception on municipalities of Benin at higher risks of the most important infectious diseases that affect dairy cattle. A total of 114 cattle keepers were enrolled from 12 municipalities known for their high dairy production in the country and their neighbouring municipals. Data were collected from August 2013 to January 2014 and subjected to a principal component analysis (PCA) followed by an ascending hierarchical classification (AHC). The study revealed that the most important infectious diseases that affect milk production according to herders are dermatophilosis, Foot-and-Mouth disease and CBPP. Tchaourou (in the North) and Dassa-Zoume (in the Centre) were reported as municipalities at higher risks of contamination. The estimation of the prevalence of these diseases and the identification of their associated risk factors is needed for devising adequate control strategies.

Comparison of Aquitaine and Rioja Red Wines: Characterization of Their Phenolic Composition and Evolution from 2000 to 2013.

Wine chemical analysis was carried out on 194 commercial blended red wines produced by two major wine-growing areas—the Aquitaine (France) and Rioja (Spain) regions—in order to compare the wines of both regions. Anthocyanins and derived pigments, tannins and derivatives were identified and quantified by HPLC-DAD-ESI-MS/MS (high pressure liquid chromatography coupled to diode array detector and mass spectrometry using the electrospray ionization interface). Mean degree of polymerization (mDP) was determined. The influence of the wine-growing region and the predominance of the properties of some grape varieties used are confirmed by the significant differences observed between both regions. Rioja and Bordeaux “generic” (Bordeaux and Bordeaux-Supérieur appellations) red wines showed the highest anthocyanic content and the highest mDP, as these wines are in a majority made from Merlot (Bordeaux “generic”) and Tempranillo (Rioja). On the contrary, Bordeaux “specific” regions (Blayais, Médoc, Graves, and Libournais) showed the red wines with the highest total phenolic content and tannin concentration, as the predominant grape variety used is Cabernet Sauvignon. A principal component analysis (PCA) and a hierarchical ascendant classification (HAC) suggesting patterns between the chemical parameters and the distribution of the red wines in three groups were proposed. The comparison of the two wine-growing areas also reveals some similarities between the various grape varieties used. A general effect of a progressive decrease in anthocyanins, anthocyanin-derived pigment and tannins is observed for older wines.

Una aproximación a las tipologías en la investigación sociológica a partir de los estilos de vida de homosexuales masculinos en Lima

In this paper we present a heuristic pathway for the construction of typologies in sociological research. We show the main characteristics of the types, their relationship with the concepts of common sense and their place within scientific concepts. At the same time, using data from a survey conducted in late 2014 as part of an ongoing research about the forms of subjectivation of homosexuality in Lima, we present a typology of the lifestyles of men who practice homoeroticism. With this presentation we seek to reconstruct the modus operandi of the development of typologies, as it articulates the theoretical and technical-methodological research levels. For the first level we draw upon a brief framework for the analysis, as for the second we use two techniques of statistical analysis: the multiple correspondence analysis (MCA) and the hierarchical ascendant classification (HAC).

Multiyear time-lapse ERT to study short- and long-term landslide hydrological dynamics

The geology of the “Vence” landslide (0.8 million m3, south-eastern France) explains the complex hydrology of the site which plays a key role in the destabilization of the slope (water circulation within the sliding mass, fluid exchanges between superficial layers and deep karstic aquifer through faults). To understand fluid circulations within the unstable slope, a 9.5-year multi-parametric survey was set up. The survey combines electrical resistivity tomography (daily acquisition), rainfall records since 2006 and boreholes monitoring groundwater level since 2009. The objective of this work is to present an automated clustering analysis applied to the ERT data enabled to locate geological units displaying distinct hydrogeological behaviours. Clustering analysis, based on a hierarchical ascendant classification (HAC), helped to simplify the ERT section isolating three groups of apparent resistivity values. Comparing the variations of these clusters’ behaviours in time to the variations of the groundwater levels on site, we identified hydrogeological units. The role of the faults cutting the substratum is thereby highlighted. It is the simultaneous analysis of such a large real dataset that allowed obtaining robust results characteristic of the long-term behaviour of the natural hydrogeological system. This type of qualitative information on the variability of the slope hydrogeological behaviour both spatially and temporally is crucial to help improving the conversion of resistivity data into hydrologic quantities. Indeed, the definition of petrophysical models to convert ERT measurements into hydrological measurements should be site-specific and take into account the spatial and temporal variability of the medium. In this work, we show a method that can also help to focus on the areas in depth that have different levels of permeability and observe how the saturation degree evolves in time. This can be used to optimize the location of additional instrumentation (such as temperature probes and chemical sampling) and, thus, help in the prevention of the risk in such problematic areas.

Knowledge management for business intelligence measurement in an e-business system

Knowledge management (KM) can be defined as the set of activities involved in discovering, capturing, sharing and applying knowledge to enhance, and the strategic impact of knowledge. Business intelligence (BI) is the process of enhancing data into information and into knowledge, in the field of business. E-Business refers to any business that uses the internet and related technologies. This paper introduces the role of knowledge management, for BI providing the understanding of the application of KM with explaining the usefulness of knowledge sharing system for BI in the dynamic transformation of explicit knowledge and tacit knowledge in e-business system. Four indices and four metrics, applied innovatively for the first time in the field of e-business, provide capabilities for examining data with web usage analysis in an online store. Two techniques, the hierarchical ascendant classification (HAC) and the product classification algorithm (PCA) are applied with the aid of the aforementioned measures in this e-business system.

Knowledge management for business intelligence measurement in an e-business system

Knowledge management (KM) can be defined as the set of activities involved in discovering, capturing, sharing and applying knowledge to enhance, and the strategic impact of knowledge. Business intelligence (BI) is the process of enhancing data into information and into knowledge, in the field of business. E-Business refers to any business that uses the internet and related technologies. This paper introduces the role of knowledge management, for BI providing the understanding of the application of KM with explaining the usefulness of knowledge sharing system for BI in the dynamic transformation of explicit knowledge and tacit knowledge in e-business system. Four indices and four metrics, applied innovatively for the first time in the field of e-business, provide capabilities for examining data with web usage analysis in an online store. Two techniques, the hierarchical ascendant classification (HAC) and the product classification algorithm (PCA) are applied with the aid of the aforementioned measures in this e-business system.

Physico-Chemical Characterization of Industrial Liquid Discharges of Soap Factories in Abidjan, Côte D’Ivoire

This work deals with the efficient management of industrial liquid discharges from soap factories (ILDS) in the region of Abidjan. The aim of this work is to evaluate the physico-chemical quality of these discharges as well as the different types of pollution generated. Seventeen (17) industrial soap sources were studied through fourteen (14) global pollution parameters (T, pH, electrical conductivity EC, redox potential EH, suspended matter SM, COD, BOD5, biodegradability factor BF, , , , , total iron and ). A liquid waste collection campaign was done during six weeks from February to March 2016, corresponding to a period of intensive activity of these industries. The samples were analyzed according to the norms of the French Standardization Agency (AFNOR). Results were compared with the Ivorian guide values recommended by the Classified Installations Inspection Service (CIIS). Principal Component Analysis (PCA) is allowed to evaluate the pollution induced by these factories’ rejection. In addition, Ascending Hierarchical Classification (AHC) method leads to classify soap factories into three groups according to the physico-chemical quality of their releases. Moreover, the estimation of the biodegradability factor is permitted to know the state of the biodegradability of these effluents.

Molecular Fingerprint Comparison of Closely Related Rose Varieties based on UHPLC-HRMS Analysis and Chemometrics.

The "Jardin de Granville" modern rose variety not only combines the morphological properties of its two parental cultivars, but also possesses better agronomic characteristics (abundant blooms, strong growth and vitality, high resistance to common rose diseases). In addition, it shows remarkable biological properties such as a high ability to decrease inflammatory and oxidative stress on skin cells. That is why Parfums Christian Dior selected this rose variety to be an active ingredient in luxury cosmetics. To identify the characteristic molecular signature of "Jardin de Granville" compared with its parents "Annapurna" and "John Clare", by the mean of a non-targeted metabolomic comparison. Wood, flower and leaf hydro-alcoholic extracts were analysed by UHPLC-ESI-HRMS. The fingerprints were then submitted to unsupervised multivariate analyses involving principal component analysis (PCA) and hierarchical ascendant classification (HAC). Analysis of variance (ANOVA) was finally performed to highlight the significant differences in each group of organs. The extracts were composed of phenolic compounds such as hydrolysable and condensed tannins and flavonol derivatives. Three groups of extracts were clustered as a function of the variety. The compounds overexpressed in "Jardin de Granville" variety were highlighted thanks to ANOVA test. Flower was the most discriminative organ with 15 overexpressed molecules. Auto MS/MS analyses led to their tentative identifications. The non-targeted metabolomic approach revealed the importance of tannins to discriminate close rose varieties. The overexpressed hydrolysable tannins characteristic of "Jardin de Granville" can be responsible for the antioxidant and anti-inflammatory properties of the rose cosmetic ingredients. Copyright © 2016 John Wiley & Sons, Ltd.

Influence of Morphological Variability and Habitat on the Chemical Composition of Essential Oils of an Algerian Endemic Origanum Species (Origanum floribundum Munby).

The genus Origanum L. (Lamiaceae) enjoys a socioeconomic interest and constitutes one of the most popular spices. In the literature, the study of this taxon is limited mainly to the chemical composition, antimicrobial, antifungal, and antioxidant activities of the essential oils. In Algeria, few works have been done in this area, including the endemic and rare species: Origanum floribundum Munby. In this study, our contribution highlights the influence of the ecological parameters and of the variation of morphological traits on the chemical composition and the antioxidant activity of the essential oils of six populations. The major oils constituents are carvacrol, γ-terpinene, and p-cymene with carvacrol predominance (31.8 - 60.8%) in over five populations (MS1 - MS4 and MS6). However, the population of Ain Terraeur (MS5) of which individuals present a foliar polymorphism, distinguishes itself by p-cymene predominance (42.6%). This would denote a new chemotype and/or variety which seem well differentiated on the dendrogram of the Ascending Hierarchical Classification (A.H.C) and its foliar morphology. The antioxidant activity of the six samples evaluated by the scavenging activity of free radicals DPPH(•) and ABTS(•+) showed a potent efficiency for the sample with foliar polymorphism population (IC50 = 51.6 ± 0.31 and 12.71 ± 0.37 μg/ml, respectively).

Characterization of relative abundance of lactic acid bacteria species in French organic sourdough by cultural, qPCR and MiSeq high-throughput sequencing methods

In order to contribute to the description of sourdough LAB composition, MiSeq sequencing and qPCR methods were performed in association with cultural methods. A panel of 16 French organic bakers and farmer-bakers were selected for this work. The lactic acid bacteria (LAB) diversity of their organic sourdoughs was investigated quantitatively and qualitatively combining (i) Lactobacillus sanfranciscensis-specific qPCR, (ii) global sequencing with MiSeq Illumina technology and (iii) molecular isolates identification. In addition, LAB and yeast enumeration, pH, Total Titratable Acidity, organic acids and bread specific volume were analyzed. Microbial and physico-chemical data were statistically treated by Principal Component Analysis (PCA) and Hierarchical Ascendant Classification (HAC). Total yeast counts were 6 log10 to 7.6 log10CFU/g while LAB counts varied from 7.2 log10 to 9.6 log10CFU/g. Values obtained by L. sanfranciscensis-specific qPCR were estimated between 7.2 and 10.3 log10CFU/g, except for one sample at 4.4 log10CFU/g. HAC and PCA clustered the sixteen sourdoughs into three classes described by their variables but without links to bakers' practices. L. sanfranciscensis was the dominant species in 13 of the 16 sourdoughs analyzed by Next Generation Sequencing (NGS), by the culture dependent method this species was dominant only in only 10 samples. Based on isolates identification, LAB diversity was higher for 7 sourdoughs with the recovery of L. curvatus, L. brevis, L. heilongjiangensis, L. xiangfangensis, L. koreensis, L. pontis, Weissella sp. and Pediococcus pentosaceus, as the most representative species. L. koreensis, L. heilongjiangensis and L. xiangfangensis were identified in traditional Asian food and here for the first time as dominant in organic sourdough. This study highlighted that L. sanfranciscensis was not the major species in 6/16 sourdough samples and that a relatively high LAB diversity can be observed in French organic sourdough.

Typology Of Cattle Herds In Transhumance In The Classified Forest Of Upper Alibori Northern Benin

To characterize the cattle herds in transhumance in the classified forest of upper Alibori (CFUA) north of Benin, an investigation of 132 cattle herds with a total of 11,020 head was carried out. Using the methods of factorial analysis of multiple correspondences (FAMC) and ascending hierarchical classification (AHC), a typology of four types of transhumant cattle herds were established. Cattle herds of type 1 (17.5% of the sample) were riparian of CFUA. They were led by young herdsmen (17 ± 3 years), all parents of herds’ managers to whom they use to make all decisions concerning these herds whose average size is low (44 ± 20 head). Type 2 cattle herds (28.8% of the sample) were from the neighboring commons of CFUA and were led by two relatively young herdsmen (26 ± 3 years) and mostly parents of herds’ managers with which they conferred to make decisions. These herds had an average size of 94 ± 20 head. The third type (43.9% of the sample) consisted of transhumant herds from distant commons, passing through the CFUA towards other protected areas. They had a high size (112 ± 13 head) and were conducted by two relatively young herdsmen (31 ± 4 years) and mostly parents of herds’ managers. Decisions were taken by the herds’ managers sometimes in consultation with the herdsmen. The migratory herds of type 4 (9.8% of the sample) from neighboring countries. They went through the CFUA towards protected areas further south with a very high size (144 ± 15 head). These herds were conducted generally by two or three herdsmen whose average age was 36 ± 4 years and were heavily involved in decision making in consultation with the herds’ managers. The typology implementation will allow us to analyze the different transhumance management modes in the CFUA.

Clustering Suicide Attempters: Impulsive-Ambivalent, Well-Planned, or Frequent.

Attempts to predict suicidal behavior within high-risk populations have so far shown insufficient accuracy. Although several psychosocial and clinical features have been consistently associated with suicide attempts, investigations of latent structure in well-characterized populations of suicide attempters are lacking. We analyzed a sample of 1,009 hospitalized suicide attempters that were recruited between 1999 and 2012. Eleven clinically relevant items related to the characteristics of suicidal behavior were submitted to a Hierarchical Ascendant Classification. Phenotypic profiles were compared between the resulting clusters. A decisional tree was constructed to facilitate the differentiation of individuals classified within the first 2 clusters. Most individuals were included in a cluster characterized by less lethal means and planning ("impulse-ambivalent"). A second cluster featured more carefully planned attempts ("well-planned"), more alcohol or drug use before the attempt, and more precautions to avoid interruptions. Finally, a small, third cluster included individuals reporting more attempts ("frequent"), more often serious or violent attempts, and an earlier age at first attempt. Differences across clusters by demographic and clinical characteristics were also found, particularly with the third cluster whose participants had experienced high levels of childhood abuse. Cluster analysis consistently supported 3 distinct clusters of individuals with specific features in their suicidal behaviors and phenotypic profiles that could help clinicians to better focus prevention strategies.

Technical-urbanistic infrastructure in the Romanian Danube Valley: Urban vs. rural territorial disparities

Infrastructure, particularly technical one, is basis of economic activities both in urban and rural areas. The Romanian sector of the Danube Valley covers a large area, in which the life of resident communities is shaped by the River (1,075 km long). At present, 266 local administrative units (LAU2) in the Romanian Danube Valley number 238 communes, 28 municipia and towns and a population of 1.7 million inhabitants. The study relies on the data provided by the National Institute of Statistics, the results of the Population and Housing Census (2011) and TEMPO Online Database (Internet 1). Hierarchizing LAU2 in terms of the technical-urbanistic infrastructure was made by the Hierarchical Ascending Classification (HAC). The aim was to group together territorial-administrative units by their parametric variables. There are many Danube Valley communities still unconnected to local drinking-water and sewerage systems, a restrictive factor in drawing potential investments into local economies. The study points out that the large Danubian port-cities also have the longest water and natural gas supply networks, as well as the greatest proportion of dwelling-houses connected to these systems. A fairly good situation have also some rural settlements lying close to big municipia or to tourist towns (in Danube Gorge and Danube Delta).

Water pollution evaluation of Oued Boudjemaa (Algeria)

Oued Boudjemaa represents a very important point for fishing and swimming in Eastern Algeria (Annaba), which makes the water quality an imperative question. To study its water quality, samples were taken from five different points along the stream for 12 months, and the physicochemical measurements were used to calculate pollution indices. The main sources of the river water pollution were domestic waste and agricultural waste rich in nutrients. Using Lisec index, the organic pollution index and the Institute for Hygiene and Epidemiology, results showed that the water quality ranged from good to very bad. For a better understanding, hierarchical ascendant classification were used to classify the sampling points according to type of discharged water, on the basis of the similarities in the chemical components of the water, three groups were found: low pollution, urban pollution, urban and agricultural pollution.

Genetic Variation of Morphological Traits and Transpiration in an Apple Core Collection under Well-Watered Conditions: Towards the Identification of Morphotypes with High Water Use Efficiency.

Water use efficiency (WUE) is a quantitative measurement which improvement is a major issue in the context of global warming and restrictions in water availability for agriculture. In this study, we aimed at studying the variation and genetic control of WUE and the respective role of its components (plant biomass and transpiration) in a perennial fruit crop. We explored an INRA apple core collection grown in a phenotyping platform to screen one-year-old scions for their accumulated biomass, transpiration and WUE under optimal growing conditions. Plant biomass was decompose into morphological components related to either growth or organ expansion. For each trait, nine mixed models were evaluated to account for the genetic effect and spatial heterogeneity inside the platform. The Best Linear Unbiased Predictors of genetic values were estimated after model selection. Mean broad-sense heritabilities were calculated from variance estimates. Heritability values indicated that biomass (0.76) and WUE (0.73) were under genetic control. This genetic control was lower in plant transpiration with an heritability of 0.54. Across the collection, biomass accounted for 70% of the WUE variability. A Hierarchical Ascendant Classification of the core collection indicated the existence of six groups of genotypes with contrasting morphology and WUE. Differences between morphotypes were interpreted as resulting from differences in the main processes responsible for plant growth: cell division leading to the generation of new organs and cell elongation leading to organ dimension. Although further studies will be necessary on mature trees with more complex architecture and multiple sinks such as fruits, this study is a first step for improving apple plant material for the use of water.

First insight into personality traits in Northern pike (Esox lucius) larvae: a basis for behavioural studies of early life stages

Personality traits have been studied for some decades in fish species. Yet, most often, studies focused on juveniles or adults. Thus, very few studies tried to demonstrate that traits could also be found in fish larvae. In this study, we aimed at identifying personality traits in Northern pike (Exos lucius) larvae. Twenty first-feeding larvae aged 21 days post hatch (16.1 +/− 0.4 mm in total length, mean +/− SD) were used to establish personality traits with two tests: a maze and a novel object. These tests are generally used for evaluating the activity and exploration of specimens as well as their activity and boldness, respectively. The same Northern pike twenty larvae were challenged in the two tests. Their performances were measured by their activity, their exploratory behaviour and the time spent in the different arms of the maze or near the novel object. Then, we used principal component analysis (PCA) and a hierarchical ascendant classification (HAC) for analysis of each data set separately. Finally, we used PCA reduction for the maze test data to analyse the relationship between a synthetic behavioural index (PCA1) and morphometric variables. Within each test, larvae could be divided in two sub groups, which exhibited different behavioural traits, qualified as bold (n = 7 for the maze test and n = 13 for the novel object test) or shy (n = 9 for the maze test and n = 11 for the novel object test). Nevertheless, in both tests, there was a continuum of boldness/shyness. Besides, some larvae were classified differently between the two tests but 40 % of the larvae showed cross context consistency and could be qualified as bold and/or proactive individuals. This study showed that it is possible to identify personality traits of very young fish larvae of a freshwater fish species.

Inferring the seasonal evolution of phytoplankton groups in the Senegalo‐Mauritanian upwelling region from satellite ocean‐color spectral measurements

AbstractWe have investigated the phytoplankton dynamics of the Senegalo‐Mauritanian upwelling region, which is a very productive region, by processing a 13 year set of SeaWiFS satellite ocean‐color measurements using a PHYSAT‐like method. We clustered the spectra of the ocean‐color normalized reflectance (reflectance normalized by a reflectance dependent on chlorophyll‐a concentration only) into 10 significant spectral classes using a Self‐Organized Map (SOM) associated with a hierarchical ascendant classification (HAC). By analyzing a 13 year climatology of these classes, we have been able to outline a coherent scenario describing the Senegalo‐Mauritanian upwelling region in terms of spatiotemporal variability of phytoplankton groups: during the onset of the upwelling (December–February), we mainly observed nanoeukaryote‐type phytoplankton in the coastal area; in April–May, the period corresponding to the maximum chlorophyll‐a concentration, the nanoeukaryote types were replaced by diatom types. This scenario is in agreement with microscope phytoplankton cell observations done during several past cruises.

Impact of Perceived Stress, Anxiety-Depression and Social Support on Coping Strategies of Parents Having A Child With Gilles de la Tourette Syndrome

PurposePrevious reports have indicated that raising a child with Gilles de la Tourette syndrome (GTS) could be considered a stressful experience. Thus our study aimed to assess the impact of perceived stress (i.e. parental cognitive perception of their child's disorder) and social support (number of people surrounding the subject providing support) on coping strategies—defined as processes of restoring balance between excessive demands and inadequate resources—of parents having a child with GTS. MethodsTwenty-eight parents of 21 patients with GTS (aged 6 to 16years) completed questionnaires on perceived stress (ALE Scale), social support (SSQ6), coping strategies (WCC-R) and anxiety–depression (HAD). ResultsPrincipal component analysis showed a negative correlation between social support on one side and perceived stress and anxiety/depression on the other. Problem- and emotion-focused coping both correlated with social support, all of them being independent from perceived stress and anxiety/depression. Hierarchical ascendant classification showed three clusters of individuals in our parents' groups: i) those having high scores in perceived stress and anxiety–depression; ii) those having high scores in social support associated with low scores in perceived stress; iii) parents having lower than average scores on both problem- and emotion- focused coping and social support. ConclusionOur results reinforce the need for developing training programs for parents with GTS children to better understand and tolerate the disorder to decrease their stress.

Understanding farm trajectories and development pathways: Two decades of change in southern Mali

Institutional support for smallholders has been the motor for the expanding cotton production sector in southern Mali since the 1970s. Smallholder farms exhibit diverse resource endowments and little is known on how they benefit from and cope with changes in this institutional support. In this paper we explore farm trajectories during two decades (1994 to 2010) and their link with farm resource endowment and government support. We distinguished a favourable period for cotton production and an unfavourable period during which institutional support collapsed. A panel survey that monitored 30 farms in the Koutiala district in southern Mali over this period was analysed. Based on indicators of resource endowment and using Ascending Hierarchical Classification (AHC), farms were grouped into four types: High Resource Endowed farms with Large Herds (HRE-LH), High Resource Endowed (HRE) farms, Medium Resource Endowed (MRE) farms and Low Resource Endowed (LRE) farms. Average yield, labour productivity and food self-sufficiency status of each type were calculated. Farms remaining in the same type were classified as ‘hanging in’, while farms moving to a type of higher yields, labour productivity and food self-sufficiency status were classified as ‘stepping up’, and farms following the opposite trajectory of deteriorating farming conditions were classified as ‘falling down’. The LRE farms differed from all other farm types due to lower yields, while both LRE and HRE farms differed from the MRE and HRE-LH farm types due to a combination of less labour productivity and less food self-sufficiency. During those two decades, 17% of the farms ‘stepped up’, while 70% of the farms remained ‘hanging in’, and only 13% of the farms ‘fell down’. We found no obvious negative impact of the collapse of government support on farm trajectories. For MRE, HRE and HRE-LH farms, average N and P use intensity increased from 1994 to 2004 and then decreased during the following cotton crisis. On the other hand, organic fertilizer use intensity increased continuously over the entire monitoring period for HRE-LH and MRE farms. Crop yields did not change significantly over time for any farm type and labour productivity decreased. We discuss how technical options specific for different farm types (increase in farm equipment, sale of cereals, incorporation of legumes and intensification of milk production) and broader institutional change (improvement in finance system and infrastructure, tariffs) can enhance ‘step up’ trajectories for farming households and avoid stagnation (‘hanging in’) of the whole agricultural sector.

Repellency of Plant Extracts against the Legume Flower Thrips Megalurothrips sjostedti (Thysanoptera: Thripidae).

Megalurothrips sjostedti Trybom is an important pest of cowpea (Vigna unguiculata L.) in Africa. To propose an alternative to chemical control, the repellency of 24 plant extracts was evaluated against adult female thrips of M. sjostedti in the laboratory. Plant extracts in ethanol were separately applied on a filter paper disk in a still air visual cue olfactometer. The results showed highly significant differences in repellency among extract type, concentration and their interactions. We classified the level of repellency into four categories as strong, good, moderate and weak or non- repellent based on hierarchical ascendant classification. We identified Piper nigrum, Cinnamomum zeylanicum, Cinnamomum cassia as strong repellents. Five extracts were classified as good, eight as moderate and the remaining eight extracts were weak or non-repellent. Repellency of the extracts increased with the concentration suggesting that the behavioral response of M. sjostedti was dose-dependent. Mono- and sesquiterpene hydrocarbon compounds from seven highly repellent extracts were identified by gas chromatography-mass spectrometry (GC/MS). The use of repellent extracts could be useful in developing integrated pest management strategies for thrips on legume crops. In this regard, the specific modes of action of the identified compounds need to be investigated to incorporate them into the existing crop protection strategies.