Space use by foragers consuming renewable resources

We study a simple model of a forager as a walk that modifies a relaxing substrate. Within it simplicity, this provides an insight on a number of relevant and non-intuitive facts. Even without memory of the good places to feed and no explicit cost of moving, we observe the emergence of a finite home range. We characterize the walks and the use of resources in several statistical ways, involving the behavior of the average used fraction of the system, the length of the cycles followed by the walkers, and the frequency of visits to plants. Preliminary results on population effects are explored by means of a system of two non directly interacting animals. Properties of the overlap of home ranges show the existence of a set of parameters that provides the best utilization of the shared resource

Successful Latin American initiatives in biophysics

The II LAFeBS Congress aimed to promote a closer interaction between Latin American and Iberian Peninsula scientists in their respective fields of research, from structural proteomics to molecular bioenergetics. The speakers at this event reflected the importance and development of Biophysics in Latin American Countries, including Portugal and Spain; with 13 of them being invited to write review articles for this special issue of Biophysical Reviews. We hope that the integration of biophysics and biophysicists in Latin America, together with Portugal and Spain, through LAFeBS and POSLATAM can contribute to the future development of biophysics in these two historical partner regions.Instituto Multidisciplinario de Biología Celula

Successful Latin American initiatives in biophysics

The II LAFeBS Congress aimed to promote a closer interaction between Latin American and Iberian Peninsula scientists in their respective fields of research, from structural proteomics to molecular bioenergetics. The speakers at this event reflected the importance and development of Biophysics in Latin American Countries, including Portugal and Spain; with 13 of them being invited to write review articles for this special issue of Biophysical Reviews. We hope that the integration of biophysics and biophysicists in Latin America, together with Portugal and Spain, through LAFeBS and POSLATAM can contribute to the future development of biophysics in these two historical partner regions.Instituto Multidisciplinario de Biología Celula

Invasive Mutualists Erode Native Pollination Webs

Plant–animal mutualisms are characterized by weak or asymmetric mutual dependences between interacting species, a feature that could increase community stability. If invasive species integrate into mutualistic webs, they may alter web structure, with consequences for species persistence. However, the effect of alien mutualists on the architecture of plant–pollinator webs remains largely unexplored. We analyzed the extent of mutual dependency between interacting species, as a measure of mutualism strength, and the connectivity of 10 paired plant–pollinator webs, eight from forests of the southern Andes and two from oceanic islands, with different incidences of alien species. Highly invaded webs exhibited weaker mutualism than less-invaded webs. This potential increase in network stability was the result of a disproportionate increase in the importance and participation of alien species in the most asymmetric interactions. The integration of alien mutualists did not alter overall network connectivity, but links were transferred from generalist native species to super-generalist alien species during invasion. Therefore, connectivity among native species declined in highly invaded webs. These modifications in the structure of pollination webs, due to dominance of alien mutualists, can leave many native species subject to novel ecological and evolutionary dynamics

Sublittoral soft bottom communities and diversity of Mejillones Bay in northern Chile (Humboldt Current upwelling system)

The macrozoobenthos of Mejillones Bay (23°S; Humboldt Current) was quantitatively investigated over a 7-year period from austral summer 1995/1996 to winter 2002. About 78 van Veen grab samples taken at six stations (5, 10, 20 m depth) provided the basis for the analysis of the distribution of 60 species and 28 families of benthic invertebrates, as well as of their abundance and biomass. Mean abundance (2,119 individuals m-2) was in the same order compared to a previous investigation; mean biomass (966 g formalin wet mass m-2), however, exceeded prior estimations mainly due to the dominance of the bivalve Aulacomya ater. About 43% of the taxa inhabited the complete depth range. Mean taxonomic Shannon diversity (H', Log e) was 1.54 ± 0.58 with a maximum at 20 m (1.95 ± 0.33); evenness increased with depth. The fauna was numerically dominated by carnivorous gastropods, polychaetes and crustaceans (48%). About 15% of the species were suspensivorous, 13% sedimentivorous, 11% detritivorous, 7% omnivorous and 6% herbivorous. Cluster analyses showed a significant difference between the shallow and the deeper stations. Gammarid amphipods and the polychaete family Nephtyidae characterized the 5-mzone, the molluscs Aulacomya ater, Mitrella unifasciata and gammarids the intermediate zone, while the gastropod Nassarius gayi and the polychaete family Nereidae were most prominent at the deeper stations. The communities of the three depth zones did not appear to be limited by hypoxia during non-El Niño conditions. Therefore, no typical change in community structure occurred during El Niño 1997–1998, in contrast to what was observed for deeper faunal assemblages and hypoxic bays elsewhere in the coastal Humboldt Current system

Procesos urbanos en acción: ¿Desarrollo de ciudades para todos?

La presente colección Ciudades de la Gente representa a hombres y mujeres cuya cultura popular, producto de las mezclas de todos aquellos que vivían y otros que han llegado a nuestros territorios, han hecho de lugares declarados como no aptos, lugares donde vivir, y han creado dentro de nuestras ciudades, la extensión de lo distinto. Son hombres y mujeres cuyo trabajo, el que tienen para aportar, junto al de otros y otras de su misma condición, les ha permitido autoproducir interesantes y sin duda bellos espacios donde convivir. Los profesores e investigadores miembros del Grupo de Trabajo Hábitat Popular e Inclusión Social de CLACSO, nos unimos a todos aquellos hacedores que, superando los miedos y con deseos de avanzar, se atreven a caminar por lo desconocido y a no conformarse con lo conocido de otras realidades, buscando en conjunto afirmar, como derechos universales, las posibilidades de vidas dignas y de construcciones colectivas dentro de nuestras ciudades. Emprendemos la tarea de describir e interpretar el hábitat popular y la inclusión social, abriendo posibilidades para que, experimentados y debutantes líderes populares e investigadores, hablen sobre "las ciudades de la gente" de muy diversos modos

Clínicas del trabajo en Chile : tres experiencias de intervención en una sociedad dañada por la gestión ‘managerial’

El artículo se propone problematizar el proceso de transformaciones del trabajo contemporáneo en Chile. Se describen tres experiencias desde las clínicas del trabajo (educacional, psicosocial y socioanálisis) en diferentes escenarios laborales. A su vez, se realiza una reflexión sobre la pertinencia de la clínica del trabajo como forma de intervención para contribuir a la comprensión de los procesos subjetivos de los trabajadores, en su dimensión individual, grupal y política.O artigo propõe-se problematizar o processo de transformações do trabalho contemporâneo no Chile. Três experiências são descritas a partir de estudos desenvolvidas na perspetiva das clínicas do trabalho (educacional, psicossocial e socioanálise) em diferentes cenários de trabalho. A seguir, faz-se uma reflexão sobre a relevância da abordagem da clínica do trabalho como forma de intervenção que contribui para a compreensão dos processos subjetivos dos trabalhadores, nas suas dimensões individual, grupal e política.L'article propose une problématisation du processus de transformation du travail contemporain au Chili. Trois expériences sont décrites au départ d’études menées selon la perspective des cliniques de travail (éducatives, psychosociales et socio-analytiques) dans différents scénarios de travail. Une réflexion est menée ensuite à propos de la pertinence de l’approche de la clinique du travail, définie en tant que mode d’intervention contribuant à la compréhension des processus subjectifs des travailleurs, dans leur dimension individuelle, de groupe et politique.The paper aims at problematizing the process of contemporary work transformations in Chile. Three experiences are described from a clinical point of view (pedagogical, psychosocial and socio-analytical) in different work scenarios. Then, it reflects on the relevance of the clinical approach as a form of intervention, which contributes to the understanding of the workers’ subjective processes, in their individual, group and political dimensions