Studies on reproduction of the mullet Mugil platanus Günther, 1880 (Actinopterygii, Mugilidae) from the Mar Chiquita coastal lagoon, Argentina: Similarities and differences with related species

The aim of the present study is to provide the first results on the reproductive biology of Mugil platanus, from the Mar Chiquita coastal lagoon (Argentina). To address this topic, we employed mainly female gonads, at both microscopic and macroscopic levels. The following stages of oocyte development were observed: (A) oogonias, (B) primary growth oocyte, (C) cortical alveolus stage, (D) yolked oocytes, and (E) atretic follicle. Also five of the seven stages of gonad maturity were macro and microscopically stated. The potential fecundity ranged between 1,002,026 and 2,548,769 yolked oocytes, with a mean of around 1,800,000 oocytes. The length at first maturity (L 50) was 450.6 total length (TL) and 367.7 standard length (SL) for females, 436.3 TL and 354.9 SL for males, showing a late sexual maturity for both sexes. Seasonal changes in gonadosomatic index (GSI) of females were observed. The mean GSI was ≤1 during six months of the year (January, June-October). Two modes in the ovarian maturation were observed, the most important in April-May and a secondary one in November-December. Both modes, correlated with the CPUE values, are indicative of the mullet migration from the coastal lagoon towards the sea for spawning. Differences and similarities have been found between Mugil platanus and other mugilid species (Mugil cephalus, Mugil curema, Liza aurata, Liza abu, Liza argentea, Myxus elongatus, and Valamugil cunnesius), from the reproductive point of view. The length at first maturity obtained for M. platanus is higher than in other mugilid species and when a relationship between maximum length and L 50 is established the percentage corresponding to Mugil platanus is 75%, while the others range between 50 and 61%.Fil: González Castro, Mariano. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Departamento de Ciencias Marinas; Argentina. Universidad Autónoma Metropolitana-Iztapalapa; MéxicoFil: Macchi, Gustavo Javier. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Subsede Instituto Nacional de Investigación y Desarrollo Pesquero; ArgentinaFil: Cousseau, María Berta. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Departamento de Ciencias Marinas; Argentin

Hausdorff dimension in RR-analytic profinite groups

We study the Hausdorff dimension of R-analytic subgroups in an R-analytic profinite group, where R is a pro-p ring whose asso- ciated graded ring is an integral domain. In particular, we prove that the set of such Hausdorff dimensions is a finite subset of the rational numbers.Comment: 7 page

A Phase-field model study of two-dimensional dendritc growth in thermal solidification processes

A phasefield model in two dimensions with both surface energy and kinetic anisotropies is used to simulate dendritic solidification of a pure material from its undercooled melt. Two finite differences methods have been implemented and their stability regions have been compared. Different regimes of dendritic growth have been obtained from simulations, showing a good qualitative agreement with experimental observations. The dependence of the velocity and direction of growth on the system undercooling has been numerically obtained for a specific case

La lucha de un docente novel de Educación Física por el reconocimiento de su profesión narrada desde una perspectiva autobiográfica

The teaching profession is a complex, burdensome task which, nowadays, faces dilemmas such as the teacher ?s discomfort, identity crises, feelings of solitude and professional disqualification, among others. This article puts forward the way a novice PE teacher confronts the consequences derived from the social and cultural construction which surround the initial training, part of the Education Degree, and the teaching profession. At the same time, some of the strategies a teacher uses to change those beliefs are here clearly set out. Thus, the article is based on the premise that the professional identity is shaped and strengthened, closely dependent on the role society imposes on it, during this initial training and the first years of teaching assignment. This might condition the teachers self-image and self-esteem, something which could be an impediment in the pursuit of improvement.La profesión docente es una labor compleja y llena de responsabilidades que, en la actualidad, se enfrenta a dilemas como el malestar del enseñante, la crisis de identidad entre el profesorado, los sentimientos de soledad y la descualificación profesional, entre otros. En este artículo se presenta el modo en que un docente novel de Educación Física (EF en adelante) se enfrenta a las consecuencias derivadas de la construcción cultural y social que se cierne en torno a la formación inicial de los estudios de Magisterio y la profesión de educador, al tiempo que se explicitan algunas de las estrategias que emplea para lograr un cambio en estas creencias. Partimos, para ello, de la premisa de que es en la formación inicial y en los primeros años de profesión en l os que se forja y consolida la identidad profesional, estrechamente supeditada al papel que le es atribuido en la sociedad y que puede condicionar el autoconcepto y la autoestima del docente, lo que puede ser una barrera en la búsqueda de la mejora de la profesión

"Cultura y sujeto cultural" en el pensamiento de Rodolfo Kusch

Fil: González Gasqués, Gustavo