Literatura académica sobre el tema "Potenziale migratorio (migratory potential)"

The paper is part of the international debate on the theme of human mobility with a transversal and developing educational perspective in the field of Migration Studies. It presents a research work carried out in Ivory Coast on the potential educational dimension of migration related to the search for better living and working opportunities. We discuss the results related to the study of the educational conditions of a potential migrant subjects, considered as variables that affect the conformation of the migration aspiration and allow a better understanding of the situations in which the birth of the desire to leave can occur, regardless of the presence or absence of the ability to migrate. The research followed a qualitative-quantitative approach in line with the methodological framework of Mixed Methods Research, adopting an exploratory-sequential design, arriving at the construction of a transferable model of analysis of the migratory potential which is composed of four main categories: migration project, educational conditions, migratory aspiration and learning potential. The aim of this paper is to present the results to the second category. Il ruolo delle condizioni educative nella definizione del potenziale migratorio: il caso dei giovani della Costa d’Avorio. Il contributo si colloca all’interno del dibattito internazionale sul tema della mobilità umana con una prospettiva educativa trasversale e in divenire nell’ambito dei Migration Studies. Si presenta un lavoro di ricerca realizzato in Costa d’Avorio sulla dimensione formativa potenziale della migrazione legata alla ricerca di migliori opportunità di vita e di lavoro. Nello specifico vengono discussi i risultati relativi allo studio delle condizioni educative di un pubblico potenziale migrante, considerate come variabili che incidono nella conformazione dell’aspirazione migratoria e che permettono una maggiore comprensione delle situazioni in cui può verificarsi la nascita del desiderio di partire, a prescindere dalla presenza o meno della capacità di emigrare. La ricerca ha seguito un approccio quali-quantitativo in linea con l’impianto metodologico dei Mixed Methods Research, adottando un disegno di tipo esplorativo-sequenziale, arrivando alla costruzione di un modello di analisi del potenziale migratorio trasferibile e composto da quattro categorie principali: progetto di migrazione, condizioni educative, aspirazione migratoria e potenziale di conoscenza. Ai fini del presente lavoro, vengono qui presentati i risultati relativi alla seconda delle quattro categorie.

Abstract Approximately 60% of the 45 species of terns (Sternae) have an unusual form of wing molt in which a variable number of inner primaries and outer secondaries are replaced two or three times in a single year—a process that has been called “repeated molt.” Although several hypotheses have been proposed for the maintenance of repeated molt, few data exist regarding potential selective forces that may have favored the evolution of this molt strategy, and there are no explanations for the high degree of interspecific variation in the extent of repeated molt. Preliminary investigations indicated that large terns tended to have less repeated molt than small terns and that the presence of repeated molt appeared to be associated with migratory behavior. We examined these initial findings by combining data from the literature, from examinations of museum specimens, and from a recent molecular phylogeny of the terns to perform phylogenetic-comparative tests. First, we used independent contrasts to verify that the association between large terns and less repeated molt was significant and not a result of shared ancestry. Second, we used tests for binary character association to evaluate the apparent link between repeated molt and migratory behavior. The results of these tests, along with reconstructions of ancestral states, led to a potential explanation for the origin of repeated molt, in which a tropical, sedentary ancestor gave rise to several lineages that spread to temperate areas and adopted a migratory life history. With this shift to a more seasonal regime came shortened breeding periods and perhaps more time for molt, which could have led to modifications of the ancestral molting strategy and the origin of repeated molt. Efectos del Tamaño y del Comportamiento Migratorio en la Evolución de la Muda del Ala en los Gaviotines (Sternae): Un Estudio Filogenético Comparativo

Abstract ∙ The Green-backed Firecrown (Sephanoides sephaniodes; Trochilidae) is one of the most important pollinators in the temperate rainforests of southern South America, yet its life history, including migratory behavior, population dynamics, and pollination biology remain poorly studied. Furthermore, juvenile firecrowns are sexually monochromatic, making them difficult to sex, which limits understanding of sex -related ecological differences that are common in hummingbirds. Here, we report the first banding of firecrowns in mainland Chile, propose ideal band sizes, and describe a technique for sexing immature individuals using the ratio of bill length to body mass. We place our results in the context of other studies of firecrowns and discuss possible ecological and behavioral implications of sexual dimorphism. In February– June 2018, we banded 71 firecrowns in Los Ríos Region, Chile (40°S). We recommend cutting bands to 8.2 mm in length for banding birds. Sexual dimorphism is clear, with large, short-billed males, and smaller, longer-billed females. Immature males and females can be distinguished based on the ratio of bill length to body mass, which in our sample does not overlap between the two adult sexes. This ratio separated all immature individuals at the 99% confidence level (< 3.09 mm g-1 classified as male, > 3.36 mm g-1 as female), and so should be tested elsewhere in the firecrown range. The incorporation of Green-backed Firecrowns in ongoing banding programs in the region has the potential to contribute important new information about the species’ ecology and evolution as well as its role in ecosystem processes.Resumen ∙ Tamaños de anillas recomendados y una nueva técnica para el sexaje de individuos inmaduros en el Picaflor Chico (Sephanoides sephaniodes) El Picaflor Chico (Sephanoides sephaniodes; Trochilidae) es uno de los polinizadores más importantes en el bosque templado austral de Sudamérica, pero su historia natural, incluyendo comportamiento migratorio, dinámica poblacional, y biología de polinización, sigue siendo poco estudiado. Además, los juveniles son monocromáticos, lo cual los hace difícil de sexar y limita el conocimiento de las diferencias ecológicas relacionadas con el sexo, que son comunes en colibríes. En este estudio reportamos los primeros anillamientos de picaflor chico en Chile continental, proponemos los tamaños de anillas ideales, y describimos una técnica para determinar el sexo de los individuos inmaduros utilizando el cociente entre la longitud del pico y el peso corporal. Ponemos nuestros resultados en el contexto de otros estudios del picaflor chico, y consideramos posibles implicaciones del dimorfismo sexual en la ecología y el comportamiento. En febrero–junio 2018 anillamos 71 picaflores chicos en la Región Los Ríos, Chile (40°S). Recomendamos cortar las anillas a 8,2 mm de largo (longitud preformada) para anillar los picaflores. Dimorfismo sexual es claro: los machos son grandes con picos cortos, mientras las hembras son más pequeñas con picos más largas. Los machos y hembras inmaduros se distinguieron por el cociente entre la longitud del pico y el peso corporal, que en nuestra muestra no superpone entre los adultos de cada sexo. Este cociente separó todos los individuos inmaduros al nivel de confianza de 99% (< 3,09 mm g1 clasificado como macho, >3,36 mm g-1 como hembra), y debe ser evaluado en otras partes del rango de distribución de la especie. La incorporación del picaflor chico en los programas de anillamiento en la región tiene la potencial de aportar nueva información importante sobre su ecología y evolución, tanto como su rol en los procesos ecológicos.

Abstract Despite advances in tracking technologies, migration strategies remain poorly studied for many small-bodied passerines. Understanding variation within a migration strategy is important as variation impacts a population’s resilience to environmental change. Timing, pathway, and stopovers vary based on intrinsic and extrinsic factors that impact individual migration decisions and capacity. Here, we studied drivers of variation in migration across a linked population of Golden-winged Warbler (Vermivora chrysoptera) using data from 37 light-level geolocators. We tested if behaviors vary in response to extrinsic factors: season, year, and proximity to a large geographic barrier—the Gulf of Mexico—and intrinsic factors: age and wing chord. Spring migration was nearly twice as fast as fall migration, with tightly correlated arrival and departure dates that were consistent among years, in contrast to no correlation or consistency in fall. This aligns with predictions for selection to minimize time spent migrating in spring and a relaxation of that pressure in fall. Twenty-nine birds staged for multiple days (mean: 7.5, SE: 0.6) in stopover habitats before crossing the Gulf of Mexico in spring, but 6 individuals overwintering closer to the Gulf coast forewent the stopover and completed migration 8 days faster. These findings suggest birds capable of crossing the Gulf without a stopover may experience a selective advantage by minimizing total migration time. After crossing the Gulf, individuals reduced travel speed and stopover duration, indicating constraints on movement differ before and after the barrier. Wing chord, but not age, positively predicted the total distance and duration of migration, and neither varied with timing, suggesting migration distance impacts morphology, but strategies do not vary with age. Ultimately, we find undescribed stopover locations south of the Gulf are important for most of the population, while high variation in migration behaviors suggest potential resilience to changing environmental conditions. Causantes de variación en el comportamiento migratorio para una población vinculada de un paseriforme migratorio de larga distancia

La crisis económica que golpeó a Europa y particularmente a España desde el año 2008 ha tenido profundos efectos en la sociedad en general. Algunos grupos sociales, sin embargo, han sufrido con mayor rigor las consecuencias de este fenómeno, siendo el de los inmigrantes uno de más afectados. En efecto, la crisis económica ha supuesto para los inmigrantes no sólo la pérdida de empleos, sino también graves carencias en términos de vivienda, incertidumbre frente a su situación migratoria y el desmantelamiento de redes sociales ante el retorno de familiares o amigos, entre otros. Frente a este contexto, las asociaciones de inmigrantes, como recursos claves del capital social, tienen el potencial de convertirse en un espacio de apoyo para el proceso migratorio, así como para enfrentar los retos que entraña la crisis. Ante la debilidad o ausencia de redes y tejido social de apoyo de los inmigrantes, las asociaciones se han convertido en un espacio vital de asistencia para la mitigación de problemas migratorios, e, igualmente, de visibilización de sus problemáticas ante de la agenda pública. El objetivo del presente artículo es el de explorar, a partir de entrevistas, encuestas y fuentes secundarias, el papel que desempeñaron las asociaciones de inmigrantes en el escenario de crisis entre el 2008 y 2015 en España, tanto en términos de apoyo a sus afiliados como actores de visibilización de las problemáticas de este colectivo. Como conclusión se aprecia una gran diversidad de estrategias de intervención de las asociaciones de inmigrantes en múltiples aspectos, contribuyendo a paliar los efectos de la crisis en este colectivo. The economic crisis that has hit Europe, particularly Spain, since 2008 has had profound effects on society in general. Some social groups, however, have suffered more severely from the consequences of this phenomenon, with immigrants being one of the most affected. Indeed, the economic crisis has meant for immigrants not only the loss of jobs, but also serious shortages in terms of housing, uncertainty regarding their migratory situation and the dismantling of social networks in the face of the return of relatives or friends, among others. Against this backdrop, immigrant associations, as key resources of social capital, have the potential to become a space of support for the migration process, as well as for facing the challenges posed by the crisis. Thus, in the face of the weakness or absence of networks and social support networks for immigrants, associations have become a vital space for assistance in mitigating migration problems, and for making their problems visible on the public agenda. The aim of this article is to explore on the basis of interviews, surveys and secondary sources, the role played by immigrant associations in the crisis scenario between 2008 and 2015 in Spain, both in terms of support for their members and in terms of raising the visibility of the problems of this group. In conclusion, we can see a great diversity of intervention strategies of immigrant associations in multiple aspects, contributing to mitigating the effects of the crisis on this group

L’elaborato affronta il tema della Mobilità Umana e del complesso insieme di fattori soggettivi e ambientali che possono influenzare la nascita di un’aspirazione migratoria e l’effettiva realizzazione di un progetto di migrazione. Il tema viene trattato a partire dal quadro delle strategie e delle politiche globali di sviluppo umano e in materia di gestione sostenibile dei fenomeni migratori internazionali e intra-regionali. Da una parte, si fa riferimento ad una molteplicità di tipologie di migranti e migrazioni, ognuna delle quali presenta caratteristiche che variano in base ai contesti e ai soggetti interessati; dall’altra, si guarda, con focus e priorità differenti, al coinvolgimento dei paesi di origine, di transito e di destinazione. In tal senso, il caso sulla migrazione dei giovani della Costa d’Avorio riguarda un tipo di migrazione prevalentemente economica, legata alla ricerca di migliori opportunità di vita e di lavoro. Lo studio si inserisce nell’ambito della letteratura internazionale dei Migration Studies che sviluppa il nesso tra migrazione e sviluppo, l’evoluzione dei concetti di cause, determinanti e drivers della migrazione e i concetti di aspirazione e capacità migratoria. Attraverso un approccio olistico e critico-trasformativo che (nell’ambito dell’educazione degli adulti) ha fatto da guida a tutto il lavoro realizzato e sviluppando una dimensione educativa trasversale ai processi indagati, il costrutto di potenziale migratorio viene assunto come categoria analitico-interpretativa del fenomeno della mobilità umana. La ricerca empirica (realizzata durante quattro missioni di terreno nel biennio 2017-2019) si è avvalsa di un disegno metodologico di tipo esplorativo sequenziale nell’ambito dei Mixed Method Research, in cui i dati di ricerca qualitativi sono stati funzionali alla costruzione degli strumenti di ricerca quantitativi. L’obiettivo finale è stato quello di delineare un approccio evidence based per l’analisi e la gestione del fenomeno della mobilità capace di offrire elementi utili per la costruzione di strategie e politiche da applicare in contesti con potenziale migratorio e nel settore della formazione e dello sviluppo professionale dei giovani. Questo è stato possibile attraverso la validazione dei costrutti contenuti nell’ipotesi di ricerca, la definizione dei profili migratori potenziali, la validazione di uno strumento di misurazione del potenziale migratorio e la costruzione di un modello di analisi costituito da quattro categorie principali: progetto migratorio, condizioni educative, aspirazione migratoria e potenziale di conoscenza. ENGLISH The paper faces the topic of Human Mobility and the totality of the individual and environmental factors influencing the birth of a migration aspiration and the effective realization of a migration project. The topic is debated through the framework of the strategies and global policies of human development, concerning the sustainable management of migratory phenomena, either international and intraregional. On one side, reference is made to a multiplicity of migrants and migrations, showing characteristics that vary according to contexts and subjects involved; on the other, focus and different priorities are given to the involvement of countries of origin, transit and destination. In this regard, the case on Ivory Coast young people’s migration concerns a mainly economic migration, linked to the research of better life conditions and job opportunities. The study belongs to the field of international literature of Migration Studies which creates the nexus between migration and development, the evolution of causes concepts, determinants and migration drivers such as the concepts of migration aspiration and ability. Through a holistic and critical-transformative approach that (in the area of adult education) has been the work’s guideline and developing an educational dimension, transversal to the investigated processes, the construct of migratory potential is assumed as analytic-interpretative category of the human mobility phenomena. The empiric research (realized during four field researches in the biennium 2017-2019) has employed an exploratory sequential methodologic design in the field of Mixed Method Research, where the qualitative research data were functional to build quantitative tools of research. The final objective was to delineate an evidence-based approach for the analysis and management of the mobility phenomenon, able to give useful elements to build strategies and policies to be applied in contexts with migratory potential and in the area of education and professional development of the youngest. This was made possible through the validation of constructs contained in the research hypothesis, the definition of potential migratory profiles, the validation of an instrument measuring the migratory potential and the construction of an analysis model made by four main categories: migratory project, education conditions, migration aspiration and knowledge potential.