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People who suffer political violence (PV) are at risk of developing mental illness, chronic noncommunicable diseases, chronic pain, and decreased life expectancy. However, these indicators have been studied primarily in war veterans and refugees. The objective of this study was to estimate the prevalence of chronic musculoskeletal pain (CMP) and central sensitization-related symptoms (CSRS) in Chilean victims of PV during the 1973 to 1990 dictatorship. A cross-sectional observational multicenter study was conducted. Three hundred twenty-five people from six centers of a Ministry of Health of Chile program participated. The presence of CMP was determined by a history of pain ≥3 months, and CSRS was determined using the central sensitization inventory. About 69.23% of the sample had CMP (76.85% of females and 56.56% of males). About 60% of people with CMP showed a high level of CSRS severity (66.67% females and 44.93% males). Females presented significantly higher proportions of CMP ( p  < .001), and there was an association between CSRS severity and being female ( p  = .004). Chilean victims of PV during the 1973 to 1990 dictatorship presented a high prevalence of CMP and high-level CSRS severity. Both conditions affected females more than males. Future studies are needed to further delve into these variables' behavior and their influence on the quality of life in this population., Competing Interests: Declaration of Conflicting InterestsThe author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Plant recruitment interactions (i.e., what recruits under what) shape the composition, diversity, and structure of plant communities. Despite the huge body of knowledge on the mechanisms underlying recruitment interactions among species, we still know little about the structure of the recruitment networks emerging in ecological communities. Modeling and analyzing the community-level structure of plant recruitment interactions as a complex network can provide relevant information on ecological and evolutionary processes acting both at the species and ecosystem levels. We report a data set containing 143 plant recruitment networks in 23 countries across five continents, including temperate and tropical ecosystems. Each network identifies the species under which another species recruits. All networks report the number of recruits (i.e., individuals) per species. The data set includes >850,000 recruiting individuals involved in 118,411 paired interactions among 3318 vascular plant species across the globe. The cover of canopy species and open ground is also provided. Three sampling protocols were used: (1) The Recruitment Network (RN) protocol (106 networks) focuses on interactions among established plants ("canopy species") and plants in their early stages of recruitment ("recruit species"). A series of plots was delimited within a locality, and all the individuals recruiting and their canopy species were identified; (2) The paired Canopy-Open (pCO) protocol (26 networks) consists in locating a potential canopy plant and identifying recruiting individuals under the canopy and in a nearby open space of the same area; (3) The Georeferenced plot (GP) protocol (11 networks) consists in using information from georeferenced individual plants in large plots to infer canopy-recruit interactions. Some networks incorporate data for both herbs and woody species, whereas others focus exclusively on woody species. The location of each study site, geographical coordinates, country, locality, responsible author, sampling dates, sampling method, and life habits of both canopy and recruit species are provided. This database will allow researchers to test ecological, biogeographical, and evolutionary hypotheses related to plant recruitment interactions. There are no copyright restrictions on the data set; please cite this data paper when using these data in publications., (© 2022 The Authors. Ecology published by Wiley Periodicals LLC on behalf of The Ecological Society of America.)

Background: In 2005, Chile became the first country in Latin America to guarantee universal free access for the diagnosis and treatment of schizophrenia. A cluster randomized control trial utilizing the Dynamic Adaptation Process framework is underway to adapt and test the OnTrack coordinated specialty care model to provide recovery-oriented, person-centered care by a multidisciplinary team for individuals with first episode psychosis (FEP) in Chile., Methods: A qualitative formative research study was conducted to inform the initial adaptation of the OnTrack Chile (OTCH) program. We conducted key informant interviews ( n = 17) with various stakeholders (policymakers; directors/managers of community mental health centers; mental health professionals) and focus group discussions ( n = 6) with individuals with FEP and caregivers ( n = 35 focus group participants total). Data was analyzed using thematic analysis, organized by participants' perspectives on the benefits, barriers, and recommendations for the key principles, multidisciplinary team, psychosocial components, and the training and supervision model of OnTrack., Results: Participants expressed enthusiasm and support for OnTrack's recovery-oriented and person-centered principles of care. While many participants lauded the emphasis on shared decision-making and family involvement, some reported reticence, citing that it is culturally normative for patients and families to adopt a passive role in treatment. Peer specialists, and the family psychoeducation and support and supported education and employment components were perceived as aspects that could encourage the promotion of personhood and autonomy development. However, implementation challenges, including the prevailing biomedical approach, professional hierarchy, and the lack of infrastructure, human, and financial resources necessitate some modifications to these aspects. Some mental health professionals further conveyed reservations regarding the perceived hierarchical structure of the supervision model., Conclusion: OnTrack represents a shift from a biomedical model to a valued, aspirational, person-centered and culturally responsive model that focuses on recovery, shared decision-making and psychosocial care. With the appropriate governmental and agency-level provision of resources and modifications to some of the program components, particularly regarding the shared decision-making framework, peer specialist, family engagement, and the training supervision model, OTCH could be a transformative program for a more comprehensive, evidence-based care for individuals with FEP in Chile., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Le, Choe, Burrone, Bello, Velasco, Arratia, Tal, Mascayano, Jorquera, Schilling, Ramírez, Arancibia, Fader, Conover, Susser, Dixon, Alvarado, Yang and Cabassa.)

Objective: This pilot randomized controlled trial evaluated the effectiveness of critical time intervention-task shifting (CTI-TS) for people with psychosis in Santiago, Chile, and Rio de Janeiro. CTI-TS is a 9-month intervention involving peer support workers and is designed to maintain treatment effects up to 18 months., Methods: A total of 110 people with psychosis were recruited when they enrolled in community mental health clinics (Santiago, N=60; Rio de Janeiro, N=50). Participants within each city were randomly assigned to either CTI-TS or usual care for 9 months. Primary outcomes were quality of life, measured with the World Health Organization Quality of Life Assessment-Brief Version (WHOQOL-BREF), and unmet needs, measured with the Camberwell Assessment of Need (CAN), at 18-month follow-up. Results were analyzed according to intention-to-treat guidelines. Generalized estimating equations, with observations clustered within cities, and multiple imputation for missing data were used., Results: At 18 months, both groups showed improved primary outcomes. In both unadjusted and fully adjusted analyses, no significant differences between CTI-TS and usual care (WHOQOL-BREF question on quality of life and CAN mean number of unmet needs) were found., Conclusions: Three factors might explain the lack of difference between CTI-TS and usual care: first-contact enrollment precluded rapport prior to randomization, a minority of patients were uncomfortable with peers being on the treatment team, and primary outcome measures may not have been sensitive enough to capture the effects of a recovery-oriented intervention. The results have implications for the design of transitional services for people with psychosis, especially in Latin America.

Background: Substantial data from high-income countries support early interventions in the form of evidence-based Coordinated Specialty Care (CSC) for people experiencing First Episode Psychosis (FEP) to ameliorate symptoms and minimize disability. Chile is unique among Latin American countries in providing universal access to FEP services through a national FEP policy that mandates the identification of FEP individuals in primary care and guarantees delivery of community-based FEP treatments within a public health care system. Nonetheless, previous research has documented that FEP services currently provided at mental health clinics do not provide evidence-based approaches. This proposal aims to address this shortfall by first adapting OnTrackNY (OTNY), a CSC program currently being implemented across the USA, into OnTrackChile (OTCH), and then examine its effectiveness and implementation in Chile., Methods: The Dynamic Adaptation Process will be used first to inform the adaptation and implementation of OTCH to the Chilean context. Then, a Hybrid Type 1 trial design will test its effectiveness and cost and evaluate its implementation using a cluster-randomized controlled trial (RCT) (N = 300 from 21 outpatient clinics). The OTCH program will be offered in half of these outpatient clinics to individuals ages 15-35. Usual care services will continue to be offered at the other clinics. Given the current COVID-19 pandemic, most research and intervention procedures will be conducted remotely. The study will engage participants over the course of 2 years, with assessments administered at enrollment, 12 months, and 24 months. Primary outcomes include implementation (fidelity, acceptability, and uptake) and service outcomes (person-centeredness, adherence, and retention). Secondary outcomes comprise participant-level outcomes such as symptoms, functioning, and recovery orientation. Over the course of the study, interviews and focus groups with stakeholders will be conducted to better understand the implementation of OTCH., Discussion: Findings from this study will help determine the feasibility, effectiveness, and cost for delivering CSC services in Chile. Lessons learned about facilitators and barriers related to the implementation of the model could help inform the approach needed for these services to be further expanded throughout Latin America., Trial Registration: www., Clinicaltrials: gov NCT04247711 . Registered 30 January 2020., Trial Status: The OTCH trial is currently recruiting participants. Recruitment started on March 1, 2021, and is expected to be completed by December 1, 2022. This is the first version of this protocol (5/12/2021)., (© 2022. The Author(s).)

This study explores the beliefs and attitudes about the psychosocial mechanisms of peer support work among users who participated in Critical Time Intervention-Task Shifting (CTI-TS), which tested the acceptability and feasibility of a peer support work model to improve community-based mental health care for individuals with psychosis in Latin America. We conducted a secondary analysis of 15 in-depth interviews with CTI-TS participants in Chile, using the framework method and defined the framework domains based on five major mechanisms of peer support work identified by a recent literature review. The analysis revealed that users' perceptions of peer support work mechanisms were strongly shaped by personal motivations, beliefs about professional hierarchies, familial support, and the Chilean mental health system's incipient recovery orientation. The findings underscore the importance of adopting culturally tailored strategies to promote peer support work, such as involving mental health professionals and fostering equal-powered relationships between PSWs and users., (© 2021. The Author(s), under exclusive licence to Springer Science+Business Media, LLC part of Springer Nature.)

Background: Few studies provide clear rationale for and the reception of adaptations of evidence-based interventions. To address this gap, we describe the context-dependent adaptations in critical time intervention-task shifting (CTI-TS), a manualized recovery program for individuals with psychosis in Rio de Janeiro, Brazil and Santiago, Chile. Implications of the adaptations - incorporating a task-shifting approach and modifying the mode of community-based service delivery - are examined from users' perspectives., Methods: A secondary analysis of in-depth interviews with CTI-TS users ( n = 9 in Brazil; n = 15 in Chile) was conducted. Using the framework method, we thematically compared how participants from each site perceived the main adapted components of CTI-TS., Results: Users of both sites appreciated the task-shifting worker pair to provide personalized, flexible, and relatable support. They wanted CTI-TS to be longer and experienced difficulty maintaining intervention benefits in the long-term. In Chile, stigma and a perceived professional hierarchy toward the task-shifting providers were more profound than in Brazil. Engagement with community-based services delivery in homes and neighborhoods (Chile), and at community mental health centers (Brazil) were influenced by various personal, familial, financial, and social factors. Uniquely, community violence was a significant barrier to engagement in Brazil., Conclusion: CTI-TS' major adaptations were informed by the distinct mental health systems and social context of Santiago and Rio. Evaluation of user experiences with these adaptations provides insights into implementing and scaling-up task-shifting and community-oriented interventions in the region through the creation of specialized roles for the worker pair, targeting sustained intervention effects, and addressing socio-cultural barriers., (© The Author(s) 2021.)

Adolescent suicide is a pressing problem in Chile that has not yet been sufficiently addressed, as suicide rates have stagnated in recent years. One possible explanation could be linked to the adult-centered paradigm that continues to prevail in relation to adolescent health initiatives. In light of this, programs that seek to promote youth mental health should consider incorporating adolescents in the design process using participatory methodologies, to ensure that these initiatives are well-suited for the population. In line with this recommendation, a group of seven adolescents, 13 to 20 years of age, were incorporated into a research team to actively guide the design, development, and validation of a technology-based intervention, known as Project Clan, which was piloted to reduce adolescent suicide in schools in Chile. This group was known as the "Group of Experts," in acknowledgment of their role as experts by experience on adolescence. A qualitative case study was conducted to explore their lived experiences, through semistructured individual in-depth interviews with six members of the group. Results showed that the adolescents had a high level of interest in mental health and had experienced problems of their own or accompanied friends who were struggling, which motivated their participation in the study. They had a critical view of the previous interventions they had received through educational institutions and valued their role in the promotion of their peers' mental health through the Group of Experts. They also highlighted the importance of creating tools that complement their daily lives and provide an alternative to existing social networks, by respecting their anonymity, providing a secure place for divulgation and self-expression, and facilitating access to professional support. We conclude that programs that address issues that affect adolescents should incorporate adolescents in the decision-making and design processes to ensure the acceptability and effectivity of their interventions., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2021 Schilling, Carreño, Tapia, Mascayano, Pitronello, Santander, Jorquera, Burrone and Alvarado.)

Background: Studies on the long-term consequences of torture in survivors in Chile have only addressed the consequences for mental health, leaving aside the physical consequences., Aim: To report the causes of death in the universe of victims of the Chilean civic-military dictatorship recognized by the Reports of the National Commission for Political Prison and Torture (CNPPT) and the Advisory Commission for the qualification of Disappeared Detainees, Politically Executed individuals and Victims of Political Prison and Torture., Material and Methods: The causes of death, age at the time of death, sex, political context of death and opportunity of repair up to June 2016 are described in 38,254 victims of the Chilean civic-military dictatorship., Results: Of the universe of 38,254 victims, 9,152 (23.9%) died until June 2016. The median age at death was 68 years. The main causes of death were malignant tumors in 28%, cardiovascular diseases in 27%, respiratory diseases in 10%, digestive diseases in 9% and external causes in 8%., Conclusions: These results can inform prevention and treatment strategies for victims of the Chilean dictatorship.

Several Latin American countries have made remarkable strides towards offering community mental health care for people with psychoses. Nonetheless, mental health clinics generally have a very limited outreach in the community, tending to have weaker links to primary health care; rarely engaging patients in providing care; and usually not providing recovery-oriented services. This paper describes a pilot randomized controlled trial (RCT) of Critical Time Intervention-Task Shifting (CTI-TS) aimed at addressing such limitations. The pilot RCT was conducted in Santiago (Chile) and Rio de Janeiro (Brazil). We included 110 people with psychosis in the study, who were recruited at the time of entry into community mental health clinics. Trial participants were randomly divided into CTI-TS intervention and usual care. Those allocated to the intervention group received usual care and, in addition, CTI-TS services over a 9-month period. Primary outcomes include quality of life (WHO Quality of Life Scale - Brief Version) and unmet needs (Camberwell Assessment of Needs) at the 18-month follow-up. Primary outcomes at 18 months will be analyzed by Generalized Estimating Equations (GEE), with observations clustered within sites. We will use three-level multilevel models to examine time trends on the primary outcomes. Similar procedures will be used for analyzing secondary outcomes. Our hope is that this trial provides a foundation for planning a large-scale multi-site RCT to establish the efficacy of recovery-oriented interventions such as CTI-TS in Latin America.

Background: Latin America, and Chile in particular, has a rich tradition of community mental health services and programs. However, in vivo community-based psychosocial interventions, especially those with a recovery-oriented approach, remain scarce in the region. Between 2014 and 2015, a Critical Time Intervention-Task Shifting project (CTI-TS) was implemented in Santiago, Chile, as part of a larger pilot randomized control trial. CTI is a time-limited intervention delivered at a critical-time to users, is organized by phases, focuses on specific objectives and decreases in intensity over time. CTI-TS, which combines both the task-shifting strategy and the use of peers, introduces a novel approach to community mental health care that has not yet been tried in Chile., Aims: We aim to evaluate the feasibility, acceptability and applicability of such a community-based psychosocial intervention in urban settings in Latin America - specifically, in Santiago (Chile) from a user perspective., Method: We analyzed 15 in-depth interviews ( n = 15) with service users who participated in the intervention about their perceptions and experiences with CTI-TS through thematic analysis., Results: Three themes were revealed. The first was related to the structural characteristics of CTI-TS, especially regarding the timing, duration and phasic nature of the intervention. The second pertained to the acceptability of the in vivo community-based approach. The third theme dealt with the task-shifting aspect, that is, users' perceptions of the peer support workers and the community mental health workers., Conclusions: CTI-TS was generally acceptable in this Latin American context. Users' perspectives pointed to the need to make adjustments to some of the structural characteristics of the CTI model and to combine this type of intervention with others that can address stigma. Thus, future adaptations of CTI-TS or similar psychosocial interventions in Latin American contexts are feasible and can enhance community mental health in the region.

The necessity of providing individuals experiencing first episode psychosis with early, comprehensive, and effective treatment, in order to improve their long-term prognosis, has been widely recognized. However, despite the important role of psychosocial interventions in treatment, only a portion of patients receive this type of care, and it is often of poor quality, especially in countries with limited resources. The Critical Time Intervention (CTI) model has been shown to effectively improve clinical and social outcomes of individuals with a history of psychosis, while also being cost-effective. It is a time-limited, community-based intervention, carried out by technical community workers who are specifically trained and continuously supervised by professionals. Therefore, CTI is a promising psychosocial intervention model for individuals experiencing a first psychotic episode, in countries with limited mental health service resources.

Background: The Eating Disorders Diagnostic Scale (EDDS) is a self-administered low cost psychometric instrument with excellent levels of temporal reliability and validity., Aim: To adapt and validate the EDDS in Chile., Material and Methods: The factorial structure, internal consistency and test-retest reliability of the Spanish-language version of the EDDS was analyzed in a sample of 1964 university and high school students. The concurrent validity was tested in a sample of 50 primary care patients with ED and 59 controls, comparing its results with those of a structured psychiatric interview (CIDI)., Results: The EDDS showed a high internal consistency, moderate test-retest reliability, an appropriate factorial structure (in women) and an excellent convergent validity. Also, the diagnosis of ED obtained with the EDDS is moderately consistent with the structured psychiatric interview., Conclusions: The Spanish-language version of the EDDS showed a satisfactory psychometric behavior and a good capacity for detecting ED, according to the DSM criterion.

Low temperature treatment of dark-grown seedlings of Arabidopsis thaliana results in a rapid increase in the amount of mRNAs encoding for the major polypeptides of the light-harvesting complex of photosystem II (Lhcb1 genes). This increase is transient and seems to be due mainly to the accumulation of Lhcb1*3 transcripts, indicating that low temperature differentially regulates the expression of the Arabidopsis Lhcb1 gene family in the dark. A 1.34 kb fragment of the Lhcb1*3 promoter is sufficient to confer low temperature regulation to a reporter gene in transgenic Arabidopsis etiolated seedlings, suggesting that the regulation is occurring at the transcriptional level. The cold-induced accumulation of Lhcb1*3 mRNA is not part of a general response to stressful conditions since no accumulation is detected in response to water stress, anaerobiosis or salt stress. The amount of Lhcb1*3 mRNA decrease in response to exogenous abscisic acid (ABA) suggesting that this phytohormone acts as a negative regulator. Moreover, the accumulation of Lhcb1*3 mRNAs in cold-treated ABA deficient etiolated seedlings is higher than that of wild-type and ABA insensitive etiolated seedlings, indicating that low temperature regulation of Lhcb1*3 is not mediated by ABA.

Summary: A nonlinear selection index (NL) method was compared with restricted linear index (RI) using two experiments of upward selection for the weight/(lenght)(n) ratio in Tribolium castaneum. The first experiment was designed to increase pupal weight/(pupal length)(2) , while the second experiment was intended to improve larval weight/(larval length)(3) . Larval and pupal traits were measured at 14 and 21 days after adult emergence, respectively. There were four generations of selection in each of three replicates, the proportion selected being 20 %. The selection criterion in the NL lines was (m(1) + Ĝ(1) )/(m(2) + Ĝ(2) )(n) , where m(1) and m(2) are the population means for the numerator and denominator traits, Ĝ(1) and Ĝ(2) are the estimated additive genetic values, and n is 2 (experiment 1) or 3 (experiment 2). The restricted linear index used as the selection criterion in the RI lines was calculated to increase the numerator trait and hold the denominator constant. Responses observed for the ratios differed significantly between lines (P < .05) in both experiments, the NL lines having the greatest responses. In experiment 1, the observed response for increasing the numerator was significant in the NL line, while the observed responses were positive and significant for both traits in the RI line; lines differed significantly pupal length (P < .01). The response obtained for the ratio in experiment 2 was due to decreases in both component traits. Results of these experiments showed that the nonlinear selection indices increased ratios that included quadratic and cubic terms in the denominator. Restricted linear indices holding the denominator constant were a less efficient alternative. ZUSAMMENFASSUNG: Experimentelle Studie über die relative Wirksamkeit nicht-linearer und beschränkter Selektionsindexe für Quotienten mit quadratischen und kubischen Größen Ein nicht-linearer Selektionsindex (NL) wurde mit einem linearen Index mit Restriktion (RI) bei Tribolium mittels eines Selektionexperiments zugunsten des Quotienten Gewicht/(Länge)(n) verglichen. Das erste Experiment zielte auf Erhöhung von Gewicht der Puppe/(Länge der Puppe)(2) , während das zweite Experiment der Verbesserung von Gewicht der Larve/(Länge der Larve)(3) diente. Merkmale von Larve una Puppe wurden jeweils nach 14 und 21 Tagen gemessen in drei Wiederholungen und vier Selektionsgenerationen mit je 20% Selektion. Das Auswahlkriterium der Linien NL war (m(1) + Ĝ(1) )/(m(2) + Ĝ(2) )(n) , wobei m(1) und m(2) den Durchschnitt für Zähler- und Nennercharakteristika darstellen, Ĝ(1) und Ĝ(2) die angenommenen Werte sind und n 2 (Experiment 1) oder 3 (Experiment 2) ist. Der bei den Linien RI als Selektionskriterium verwendete Beschränkungsindex wurde zur Erhöhung des Zählers und zur Konstanthaltung des Nenners angenommen. Die Ergebnisse für den Quotienten waren bei beiden Experimenten zwischen Linien (P < .05) signifikant unterschiedlich, wobei die Reaktion der NL-Linien größer war. Beim Experiment 1 war die Reaktion der Linie NL im Zähler signifikant, während sie bei der Linie RI für beide Charakteristika positiv und signifikant war, die Linien waren signifikant verschieden hinsichtlich Länge der Puppe (P < .01). Das beim Experiment 2 erzielte Ergebnis für den Quotienten ergab sich aufgrund der Abnahme der beiden charakteristischen Komponenten. Die Ergebnisse dieser Experimente zeigten, daß die nicht-linearen Indexe die Quotienten erhöhten, welche im Nenner quadratische oder kubische Termini beinhalteten. Die linearen Indexe mit Restriktion für den Nenner des Quotienten stellten eine weniger wirksame Alternative dar. RESUMEN: Estudio experimental de la eficiencia relativa de indices de selección no lineales y con restricción para cocientes que incluyen cuadrados y cubos Un índice no lineal de selección (NL) fue comparado con un índice lineal con restricción (RI) en Tribolium, usando dos experimentos de selección a favor del cociente peso/(longitud)(n) . El primer experimento fue diseñado para incrementar peso de pupa/(longitud de pupa)(2) , mientras que el segundo experimento trataba de mejorar peso de larva/(longitud de larva)(3) . Los caracteres de larva y de pupa se midieron a los 14 y a los 21 días respectivamente. Había cuatro generaciones de selección en cada una de tres repeticiones, siendo la proporción seleccionada el 20 %. El criterio de selección en las líneas NL fue (m(1) +Ĝ(1) /(m(2) +Ĝ(2) )(n) , donde m(1) y m(2) son las medias para los caracteres numerador y denominador, Ĝ(1) y Ĝ(2) son los valores aditivos estimados, y n es 2 (experimento 1) o 3 (experimento 2). El índice con restricción usado como criterio de selección en las líneas RI fue calculado para incrementar el numerador y mantener constante el denominador. Las respuestas observadas para el cociente diferían significativamente entre líneas (P < .05) en ambos experimentos, teniendo mayor respuesta las líneas NL. En el experimento 1, la respuesta observada en el numerador fue significativa en la línea NL, mientras que fue positiva y significativa para ambos caracteres en la línea RI; las líneas diferían significativamente para longitud de pupa (P < .01). La respuesta obtenida para el cociente en el experimento 2 fue debida a la disminución de ambos caracteres componentes. Los resultados de estos experimentos mostraban que los indices no lineales incrementaban cocientes que incluían en el denominador términos cuadráticos o cúbicos. Los índices lineales con restricción para el denominador del cociente eran una alternativa menos eficiente. RÉSUMÉ: Etude expérimentale de l'efficacité relative des indices de sélection non linéares y avec restriction pour des quotients qui comportent des carrés et des cubes Nous avons comparé un index non linéaire de sélection (NL) avec un index linéaire avec restriction (RI) à Tribolium, on utilisant deux expériences de sélection en faveur du quotient poids/(Longueur)(n) . La première expérience fut conçue pour augmenter le poids de la pupe/(Longueur de pupe)(2) , tandis que la deuxième expérience essayait d'améliorer le poids de la larve/(Longueur de larve)(3) . Les caractères de larve et de pupe furent mesurés au bout de 14 et de 21 jours respectivement. Il y avait quatre générations de sélection dans chacune des trois répétitions et la proportion choisie fut celle de 20 %. On prit (m(1) + Ĝ(1) )/(m(2) + Ĝ(2) )(n) come critére de sélection dans les lignes NL, m(1) et m(2) étant les moyennes pour les caractères numérateur et dénominateur, Ĝ(1) et Ĝ(2) les valeurs additives estimées et n étant 2 (expérience 1) ou 3 (expérience 2). Le index avec restriction employé comme critère de sélection dans les lignes RI a été calculé pour augmenter le numérateur et maintenir le dénominateur constant. Les réponses obtenues pour le quotient étaient significativement différentes entre les lignes (P < .05) dans les deux expériences, la réponse plus grande étant celle de la ligne NL. Dans l'expérience 1, la réponse observée dans le numérateur fût significative dans la ligne NL, tandis qu'elle fut positive et significative pour les deux caracteres dans la ligne RI; les lignes étaient significativemcnt différentes pour la longueur de pupe (P < .01). La réponse obtenue pour le quotient dans l'expérience 2 a été due à la diminution des deux caractères composants. Les résultats de ces expériences ont montré que les indices non linéares augmentaient les quotients qui incluaient dans le dénominateur des termes quadratiques ou cubiques. Les indiceslinéaires avec restriction pour le dénominateur du quotient ont été une alternative moins efficace., (1994 Blackwell Verlag GmbH.)