La formacion de anillos de crecimiento en Fissurella crassa en el norte de Chile

Growth discontinuity in molluscs result in the formation of rings on their shells. Two kind of rings may be formed: disturbance and growth rings. Growth rings can be used to determine the age of molluscs with long life span. For this, it is necessary to know how many growth rings are formed per year. It has been demonstrated experimentally, using marked specimens, that F. crassa forms two growth rings per year at Huayquique, Northern Chile. They are formed during winter and summer. Disturbance ring formation has also been observed as a result of sawing marks on their shells. A growth curve for this species is proposed on the basis of Watford's line

La morphogenèse du ganglion stato-acoustique chez la souris normale et chez le mutant "dancer"

Doctorat en SciencesVol.1 :texte (TH-000138) ;Vol.2 :illustrationsinfo:eu-repo/semantics/nonPublishe

ETUDE MORPHOGENETIQUE DU COMPLEXE GANGLIONNAIRE STATO-ACOUSTIQUE ET DE L'OREILLE INTERNE CHEZ DES EMBRYONS DE SOURIS DANCER

Morphological and histochemical aspects of the early development of inner ear and adjacent ganglia have been studied in abnormal mouse embryos bearing gene Dc (Dancer) and collected at the 9- to the 12-day stages. Abnormalities have been found in embryos of all stages studied. Abnormal Dancer embryos (Dc/Dc and Dc/+) show a delay in neural tube closure and in cephalic neural crest migration. The developing otic region shows bilateral asymmetries. Otocyst and ganglionic defects show considerable variations, even between both sides of the same animal. Dancer embryos also exhibit a general delay in body growth and other cephalic anomalies. The invaginating otic placode does not make contact with the rhombencephalic neural wall. This defect is accompanied by a delay in otic vesicle closure and in presumptive ganglionic cells migration from the primary auditory epithelium. A delayed modelling characterizes the anterior region of the otocyst. The main structures affected are the superior and lateral semicircular ducts and the utriculus. Sensory areas of the superior and lateral ampullae and of the utricular macula show a defectuous differentiation or are missing. The posterior region of the otocyst develops normally. The lateral portion of the stato-acoustic ganglion primordium is smaller in Dancer embryos. Abnormalities also appear later on in the ganglionic lateral arm of the medial portion. The branches of the developing superior vestibular nerve may be thinner, aberrant or absent. The utricular branch is always missing. The fibers of the future inferior vestibular nerve are not affected. Certain central nerve connections are reduced or absent, or their formation is delayed in Dancer embryos. These connections are the facial motor roots and the sensitive roots of the developing superior vestibular ganglion.SCOPUS: NotDefined.jinfo:eu-repo/semantics/publishe

La morphogenèse du ganglion stato-acoustique chez la souris normale et chez le mutant "dancer"

Doctorat en SciencesVol.1 :texte (TH-000138) ;Vol.2 :illustrationsinfo:eu-repo/semantics/nonPublishe

LA MORPHOGENESE PRIMORDIALE DU GANGLION STATO-ACOUSTIQUE ET DE L'OREILLE INTERNE CHEZ L'EMBRYON DE SOURIS

The anterior epithelial sensorial zone of the otocyst is the first to become individualized and receives neuritic filaments from the anterior branch of the stato-acoustic nerve. The sensorial areas of the posterior ampulla, of the saccular macula and of the organ of Corti receive late neuritic filaments belonging to the posterior branch of the same nerve. These sensorial areas are further distinguished from the anterior sensorial zone by a less pronounced activity of the alkaline phosphatase. The two primordial neuroblastic groups of the stato-acoustic ganglion are distinguished by means of the alkaline phosphatase test, as the external group displays activity of this enzyme, while the internal group does not. Later on (at the stage of 10 1/2 days), the neuroblasts of the internal group manifest activity of the acid phosphatase. This type of neuroblast, large and with a rounded and voluminous nucleus, with its cytoplasm rich in RNA, will be found later in the two portions of the vestibular ganglion (the magno-cellular parts) and in the cochlear ganglion. The other type of neuroblast, with a less differentiated appearance, will be seen only in the vestibular ganglion (the parvicellular parts). The central neuritic ramifications of cochlear nature are the last to be discovered (at the stage of 11 1/2 days).SCOPUS: NotDefined.jinfo:eu-repo/semantics/publishe

LA MORPHOGENESE PRIMORDIALE DU GANGLION STATO-ACOUSTIQUE ET DE L'OREILLE INTERNE CHEZ L'EMBRYON DE SOURIS. I. ANALYSE DE LA MORPHOGENESE PRECOCE CHEZ LES EMBRYONS DE 9, 9 1/2 ET 10 JOURS

The distribution of RNA, polysaccharides, alkaline and acid phosphatases at successive developmental stages have been analysed in serial transverse sections of the otic region. Sections submitted to the Unna-Brachet method have permitted the study of the morphological evolution of embryonic primordia, and of the programmed cellular death sites. Certain aspects of nerve fiber development have been elucidated through observations of sections treated for alkaline phosphatase enzymatic reaction. Acid and alkaline phosphatase tests have revealed the evolution of the primitive sensory areas. Otocyst dissections have allowed a better understanding of the morphological changes which the primitive otic vesicle undergoes during this period. Several transitory histochemical and morphological features suggest the successive contribution of two different inductors in the primary morphogenesis of the normal auditory placode: the parachordal mesoderm and the rhombencephalon. In addition, the histochemical properties of the invaginating otic pit wall testify the acquisition of a double antero-posterior and dorsoventral polarization. The presumptive sensory area for the future anterior and lateral ampullae and for the utricular macula is easily localized owing to its selective alkaline phosphatase activity. This area is the first to arise from the macula communis. The first primordium of the stato-acoustic ganglion arises from cells migrating from the rostro-ventral wall of the primary auditory vesicle. In this early primordium, we found two portions, one medial and the other lateral. The latter is characterized by its alkaline phosphatase reaction and by its location dorsal to the geniculate ganglion primordium. These two primitive portions do not correspond to the future vestibular and cochlear ganglia. The central sensitive nerve fibers of the ganglionic complex appear very early, before the constitution of the different ganglionic groups. Later on, the motor fibers of the facial nerve become evident. Among the peripheric nerve connections, the anterior ramus fibers become visible earlier.SCOPUS: NotDefined.jinfo:eu-repo/semantics/publishe

THE BIOLOGY OF FISSURELLA MAXIMA SOWERBY (MOLLUSCA: ARCHAEOGASTROPODA) IN NORTHERN CHILE. 2. NOTES ON ITS REPRODUCTION

Volume: 165Start Page: 559End Page: 56

Diagnosi : Educació per a la justícia global a l’escola pràctiques (Barcelona)

Màster Oficial en Globalització, Desenvolupament i Cooperació, Universitat de Barcelona. Facultat d’Economia i Empresa. Curs: 2021-2021, Tutor/a: Xavi Martí GonzálezTreball realitzat en el marc del Màster de Globalització, Desenvolupament i Cooperació de la UB (Món-3) que pretén mostrar el grau d’implantació de la visió de l’Educació per a la Justícia Global (EpJG) en una escola pública de Barcelona, l’escola Pràctiques. La metodologia emprada per a la realització del treball, recorre l’anàlisi de la construcció del concepte cap a la idea d’educació emancipadora, el corpus legal regulador, el context de l’escola on volem estudiar quina vida té l’EpJG i a continuació, la recopilació d’informació sobre l’activitat relacionada a partir d’enquesta al personal de l’escola. Amb la informació obtinguda, detectem l’existència de sensibilitat i voluntat per part de tots els agents educadors, afegint que l’EpJG té un llarg camí per recórrer

REPRODUCTION AND DEVELOPMENT OF Dromiciops gliroides (MARSUPIALIA: MICROBIOTHERIIDAE) IN TEMPERATE RAINFORESTS OF SOUTHERN CHILE REPRODUCCION Y DESARROLLO DE Dromiciops gliroides (MARSUPIALIA: MICROBIOTHERIIDAE) EN EL BOSQUE TEMPLADO HUMEDO DEL SUR DE CHILE

The reproductive biology of Dromiciops gliroides is described from five females collected during spring (October, December 1984) in southern continental Chile. Developmental morphology of intra-uterine embryos (October litters) was examined by microscopic analysis and compared with morphological attributes of 8 pouched young (December litters). Intra-uterine embryos demonstrate ontogenetic features characteristic of altricial neonates, which migrate from the urogenital opening to the marsupium in order to complete the later stages of development. D. gliroides apparently is a monoestrus, seasonal breeder producing one litter per year. Maximum recorded litter size is four, with birth occurring in early spring (October). The life cycle of D. gliroides is subdivided into seven distinct periods: pair formation, intra-uterine development, parturition, intra-marsupium development, nocturnal family excursions, and juvenile independence. Phylogenetic relationships of D. gliroides to Neotropical and Autralian marsupials are considered by comparing aspects of reproductive biology and early life history characteristics<br>Se describen antecedentes de la biología reproductiva de Dromiciops gliroides provenientes del análisis de cinco hembras colectadas durante la primavera (octubre - diciembre) de 1984 en el sur de Chile. Se examinó el desarrollo morfológico de embriones intrauterinos con análisis microscópico y comparándolos con los atributos morfológicos de ocho juveniles en el marsupio (camadas de diciembre). Los embriones intrauterinos mostraron características embrionarias típicas de neonatos altriciales, quienes migran desde la apertura urogenital hasta el marsupio para completar los últimos estados del desarrollo. D. gliroides es, aparentemente, una especie monoéstrica, estacional, produciendo una camada por año. Se ha registrado un máximo de cuatro crías, con nacimientos que ocurren en la primavera temprana (octubre). El ciclo de vida de D. gliroides se divide en seis distintos períodos: (a) formación de pareja, (b) desarrollo intrauterino, (c) parición, (d) desarrollo intramarsupial, (e) excursiones familiares nocturnas, y (f) independencia juvenil. Las relaciones filogenéticas de D. gliroides con marsupiales del neotrópico y Australia son consideradas comparando aspectos de su biología reproductiva y características de su historia de vida tempran