701 research outputs found
Action of the Metalloproteinases in Gonadal Remodeling during Sex Reversal in the Sequential Hermaphroditism of the Teleostei Fish Synbranchus marmoratus (Synbranchiformes: Synbranchidae)
Teleostei present great plasticity regarding sex change. During sex reversal, the whole gonadincluding the germinal epithelium undergoes significant changes, remodeling, and neoformation.However, there is no information on the changes that occur within the interstitial compartment.Considering the lack of information, especially on the role played by metalloproteinases (MMPs)in fish gonadal remodeling, the aim of this study was to evaluate the action of MMPs on gonadsof sex reversed females of Synbranchus marmoratus, a fresh water protogynic diandric fish. Gonadswere processed for light microscopy and blood samples were used for the determination of plasmasex steroid levels. During sex reversal, degeneration of the ovaries occurred and were graduallyreplaced by the germinal tissue of the male. The action of the MMPs induces significant changesin the interstitial compartment, allowing the reorganization of germinal epithelium. Leydig cellsalso showed an important role in female to male reversion. The gonadal transition coincides withchanges in circulating sex steroid levels throughout sex reversion. The action of the MMPs, in thegonadal remodeling, especially on the basement membrane, is essential for the establishment of anew functional germinal epithelium.Fil: Mazzoni, Talita Sarah. Universidade Estadual Paulista Julio de Mesquita Filho; BrasilFil: Lo Nostro, Fabiana Laura. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Biodiversidad y Biología Experimental. Laboratorio de Ecotoxicología Acuática; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Biodiversidad y Biología Experimental y Aplicada. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Biodiversidad y Biología Experimental y Aplicada; ArgentinaFil: Antoneli, Fernanda. Universidade Estadual de Campinas; BrasilFil: Quagio-Grassiotto, Irani. Universidade Estadual Paulista Julio de Mesquita Filho; Brasi
Tradurre senza tradire: il mediatore linguistico e interculturale nelle piccole e medie imprese
The reflection arisen from the need for an educational concreteness and for a research on how to
make the tools at our disposal more usable for our students as future workers, has stimulated further
considerations leading to a need analysis, where the contribution of linguistic and intercultural mediation
may be the key to what seems to be a structurally impoverishing vision
Acknowledgments
Our first thanks is for you, who are reading this page and this first issue of Substantia. We do rely on you, on your interest and on your patience, on your approval and also on your sincere criticism. Substantia is the product of a great effort, of a great pleasure and of a renewed hope in the human capability to wonder about the beauty and complexity of reality and matter, and to inspect their features with the strength of reason..
Without this hope - or better without this certainty - any attempt to uncover and understand the world would be nosense and we would be pulled back to darkness. We sincerely thank the authors of this first issue: they granted us the strength of their knowledge and wisdom, and gladly accepted the challenge of a new journal.
Thank you to the members of the international Scientific Board, who offered their prestige and reliability for the benefit of the scientific level of the journal and to our colleagues in the Department of Chemistry, who wel comed the birth of Substantia.
Finally I want to express my deepest loyal gratitude to Moira Ambrosi, Antonella Capperucci, Laura Colli, Marco Fontani, Romeo Perrotta and Alessandro Pierno for sharing with me this challenging and tantalizing adventure. Their enthusiastic and tireless commitment was the first nourishment for our journal. We tried to do our best, it has been and will be a great struggle. And for sure we could have done it better.
We apologize for any mistake and we thank you - the reader of these articles - for your invaluable support and for all the suggestions that you may want to share with us in the future
Free-range and organic farming: Eggshell contamination by mesophilic bacteria and unusual pathogens
Quels encadrés pour quels types de public
Allo stato attuale la difficoltà di apprendimento di una lingua non è più
limitata alla struttura o al lessico, ma a tutte quelle sfumature che concorrono
a costituire le peculiarità di una lingua e di una cultura. A tal fine i
dizionari, specie i bilingue, si sono rivelati spesso deficitari fornendo quasi
esclusivamente le accezioni e le strutture canoniche, occupandosi molto
raramente, e talvolta impropriamente, dell’elemento lessiculturale. Per
ovviare a questa carenza, alcuni dizionari hanno cominciato ad introdurre
supplementi che esplicitano particolarità d’uso e di cultura. Talvolta si
tratta di un’impresa di merchandising piuttosto che del risultato di una
reale ricerca che soddisfi i bisogni dell’utente. Le case editrici sembrano
non tener conto del fatto che le diverse tipologie di dizionario scaturiscono
dalle esigenze del pubblico prima che dalla diversificazione delle vendite.
La nostra riflessione, attenta agli obblighi editoriali e ai bisogni dei
fruitori, rivolge lo sguardo alla pluralità del pubblico e alle sue esigenze
cercando di riassumere gli elementi necessari, indispensabili e superflui limitatamente
alle finalità che si propone ogni singolo strumento
Introduire les illustrations de la gestuelle dans les dictionnaires bilingues généraux: un premier pas vers un dictionnaire bilingue encyclopédique
A case of intersex occurrence in Steindachneridion parahybae (Steindachner, 1877) (Siluriformes: Pimelodidae) under captivity condition: A cytogenetic and morphological study
Poco se sabe sobre la biología reproductiva de Steindachneridion parahybae , una especie de teleósteo gonocorístico en peligro de extinción que habita la cuenca del río Paraíba do Sul y en éste trabajo se describe por primera vez la aparición de individuo intersexo en juvenil de S. parahybae . También se describió el aspecto normal de los ovarios y de los testículos de individuos juveniles procedentes del mismo lote de cría para su comparación; se realizó además el análisis citogenético. Un espécimen fue clasificado a priori como hembra debido a las características macroscópicas de los ovarios, con pequeños oocitos amarillos, sin flecos (característica principal de los bagres macho) y más grande que los testículos; sin embargo el análisis microscópico reveló la presencia de un ovotestis, incluyendo una espermatogénesis completa. S. parahybae presentó un número diploide, 2n = 56 cromosomas, sin evidencia de cromosomas sexuales diferenciados o supernumerarios entre ellos. Estos hallazgos pueden deberse al resultado de la exposición de los individuos a desorganizadores endocrinos o estar influenciados por las condiciones ambientales. Sin embargo no se puede descartar la posibilidad de la presencia de intersexos de forma espontánea. Por lo tanto, la importancia funcional y las consecuencias reproductivas de estas anomalías permanecen aún sin ser determinadas, sugiriendo que esta especie puede ser susceptible a los disruptores endocrinos. Estos resultados contribuyen a ampliar el conocimiento de la biología reproductiva de esta especie en peligro de extinción en condiciones de cautiverio.Little is known about reproductive biology of endangered Steindachneridion parahybae , a gonochoristic teleost species inhabiting the Paraíba do Sul River Basin, and herein is the first description of intersex in S. parahybae juvenile. The normal appearance of ovaries and testes in juvenile from the same lot of breeding were also described for comparison, even as cytogenetic analysis was performed in these juveniles. One specimen was a priori classified as female due to the macroscopic characteristic of ovaries, with small yellow oocytes, without fringes (a main characteristic of catfish male), and larger than testes; however the microscopic analysis revealed the presence of ovotestes, including the complete spermatogenesis. S. parahybae had diploid number, 2n = 56 chromosomes with no evidence of differentiated sex chromosomes or supernumerary chromosomes among them. These findings may be due to the result of exposure to endocrine disrupting compounds or may also be influenced by environmental conditions. The possibility of intersexes might also happen spontaneously and it cannot be ruled out. Therefore, the functional significance and reproductive consequences of this anomaly remain to be determined, suggesting that this species may be susceptible to endocrine disruption. These results contribute to gain expertise about reproductive biology of an endangered species in captivity.Fil: Honji, Renato Massaaki. Universidade de Sao Paulo; Brasil. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Caneppele, Danilo. Companhia Energética de São Paulo. Unidade de Hidrobiologia e Aquicultura; BrasilFil: Pandolfi, Matias. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Biodiversidad y Biología Experimental y Aplicada. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Biodiversidad y Biología Experimental y Aplicada; ArgentinaFil: Lo Nostro, Fabiana Laura. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Biodiversidad y Biología Experimental y Aplicada. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Biodiversidad y Biología Experimental y Aplicada; ArgentinaFil: Moreira, Renata G.. Universidade de Sao Paulo; Brasi
Preprints and Publication: How the Covid-19 Pandemic Affected the Quality of Scientific Production
An interesting paper recently published in Peer J. by Enrique Teran and coworkers casts light on a peculiar side effect of the Covid-19 pandemic that concerns the quality of articles that appeared as preprints in archives or as regular papers in peer-reviewed scholarly journals.
The authors report a detailed perusal of the scientific publications related to research on Covid-19 in a portion of the year 2020.
What emerges from the study is that over the total number of preprints uploaded in the archives' servers, that are not subjected to a formal peer-review process, only about 5.7% were later converted into regular articles and published in scholarly journals after a regular peer-review process. The statistics is based on a global sample of 5,061 preprints uploaded in three different archives
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