The genera Chara and Nitella (Chlorophyta, Characeae) in the subtropical Itaipu Reservoir, Brazil

The family Characeae, represented by two genera in Brazil, Chara and Nitella, is considered to include the closest living relatives of land plants, and its members play important ecological role in aquatic ecosystems. The present taxonomic survey of Chara and Nitella was performed in tributaries that join to form the Brazilian shore of the Itaipu Reservoir on the Paraná River. Thirteen species were recorded, illustrated, and described: C. braunii var. brasiliensis R.Bicudo, C. guairensis R.Bicudo, N. acuminata A.Braun ex Wallman, N. furcata (Roxburgh ex Bruzileus) C.Agardh, and N. subglomerata A.Braun, already cited for the reservoir, and C. hydropitys Reichenbach, C. rusbyana Howe, N. axillaris A.Braun, N. glaziovii G.Zeller, N. gracilis (Smith) C.Agardh, N. hyalina (DC.) C.Agardh, N. inversa Imahori, and N. microcarpa A.Braun that represent new occurrences for the Itaipu Reservoir and Paraná State. Among the species encountered, C. guairensis, N. furcata, and N. glaziovii are widely distributed, while C. hydropitys and C. rusbyana have more restricted distributions.

Preparation of mitotic chromosomes of leaf-cutting ants from the genera Atta and Acromyrmex

Some modifications were made to the methodology of Imai et al. (Jpn. J. Genet. 63: 159-185, 1988) for cytogenetic analysis of the leaf-cutting ants Atta sexdens piriventris and Acromyrmex heyeri (Hymenoptera, Formicidae), shortening preparation time and improving chromosomal preparations. The brain ganglia of prepupae were dissected in a 0.0025% hypotonic solution of colchicine, placed on a glass slide on a cold plate (4 ± 1oC) for 20 min. The material was fixed directly on the cold slide (with cold fixative I), macerated with a histological needle and fixed again with fixative I, followed by fixatives II and III, all of them cold. The slide was flame-dried right after the use of fixative III, and it was allowed to air-dry at room temperature for 2 h. The resulting metaphases presented less contracted chromosomes, with separated and well defined sister chromatids at a high frequency, when the material was processed in the manner described and stained with 3% Giemsa in phosphate buffer (pH 6.8) for 15 min.

Summa rerum genera esse tantum duo: substantiam nimirum & accidens, ex suffragio ampliss. facult. philos. in florentissimo ad Auram Athenaeo, sub umbone ... dn. mag. Simonis Tålpo, met & log. professoris famigeratissimi, consistorii Acad. assessoris gravissimi nec non annexae Pijkensis pastoris longe fidelissimi. Summos in philosophia honores aditurus dissertatione philosophica ad sobrie philosophantium examen modeste delata statuere conabitur Jeremias Wallenius J. f. Tavastensis. Ad diem 21. Nov. anni redempti orbis M. DC. XC. IV. Horis pomeridianis in auditorio maximo

Invokaatio: A.J.

Circa diversa gentium barbararum vitae genera et caussas ingenii earum culturam impedientes

Arkit: 1 arkintunnukseton lehti, A-B4 C1. - S. [2] tyhjä.

Genetic variation and evolutionary divergence within and among populations, species, and genera of the Cambarinae

Seven crayfish species from three genera of the subfamily Cambarinae were electrophoretically examined for genetic variation at a total of twenty-six loci. Polymorphism was detected primarily at three loci: Ao-2, Lap, and Pgi. The average heterozygosities over-all loci for each species were found to be very low when compared to most other invertebrate species that have been examined electrophoretically. With the exception of Cambarus bartoni, the interpopulation genetic identities are high within any given species. The average interspecific identities are somewhat lower and the average intergeneric identities are lower still. Populations, species and genera conform to the expected taxonomic progression. The two samples of ~ bartoni show high genetic similarity at only 50 percent of the loci compared. Locus by locus identity comparisons among species yield U-shaped distributions of genetic identities. Construction of a phylogenetic dendrogram using species mean genetic distances values shows that species grouping is in agreement with morphological taxonomy with the exception of the high similarity between Orconectespropinquus and Procambarus pictus. This high similarity suggests the possibility of a regulatory change between the two species. It appears that the low heterozygosities, high interpopulation genetic identities, and taxonomic mispositioning can all be explained on the basis of low mutation rates.

The Cenozoic Gonyaulacacean Dinoflagellate Genera Operculodinium Wall, 1967 and Protoceratium Bergh, 1881 and Their Phylogenetic Relationships

The palynology of Ocean Drilling Program Site 1007, leeward of the present Bahamas Bank, provides insights into upper Oligocene–lower Pleistocene dinoflagellate cyst associations in the tropical Americas. These associations are reviewed along with the sedimentary paleoenvironment to provide context for a morphological study of the cystdefined dinoflagellate Operculodinium bahamense and its comparison with the thecadefined dinoflagellate Protoceratium reticulatum which produces a cyst assignable to the cyst-defined genus Operculodinium. Detailed reconstructions of the tabulation in both species reveal strong similarities, having a sexiform hyposomal tabulation and L-type or modified L-type ventral organization. Protoceratium reticulatum has dextral torsion of the hypotheca, requiring assignation of the genus to the subfamily Cribroperidinioideae, whereas Operculodinium bahamense has neutral torsion requiring assignation to the subfamily Leptodinioideae. Results either imply polyphyletic origins for the genus Operculodinium or that combinations of ventral organization and torsion cannot always be applied rigidly to subdivide the family Gonyaulacaceae.

La aplicación de los sistemas de información como herramienta que genera ventajas competitivas en la planeación estratégica y financiera de una organización del ramo cervecero

Tesis (Maestro en Ciencias de la Administración con Especialidad en Finanzas) - U.A.N.L, 2001

La inseguridad jurídica del particular ante la desigualdad procesal que genera la interposición del jucio de Lesividad por parte de la autoridad fiscal, en el jucio contencioso administrativo

Tesis ( Maestría en Derecho Fiscal) U.A.N.L.

Gradus ad Parnassum, sive, Novus synonymorum, epitethorum, phrasium poeticarum, ac versuum thesaurus : Smetium, Januam Musarum, Delectum epithetorum, Parnassum poticum, Elegantias poticas, thesaurum Virgilii, aliosque omnes id genus libros ad posin necessarios complectens : inquo singulis syllabis appositae sunt notae quantitatis indices, un cumpotarum testimoniis ordine alphabetico adjunctis . : addita sunt genera & crementa omnia nominum ac verborum, praeterita & supina : acceduntquae ex historia, fabul & geographi ad poticam artem conferunt .

UANL

La pedagogía agradable genera mejores conocimientos

El trabajo del P.A.P. busca marcar una ruta que muestre a los sujetos de la relación educativa de forma integral (la cual en el capítulo II explicaremos en detalle), la obtención de un ambiente propicio (agradable) para generar mejores conocimientos.

¿Se puede predecir el número de cifras de un número periódico estudiando la fracción que lo genera?

Resumen basado en el de la publicación

Cultura que genera la evaluaci??n en las escuelas

Resumen tomado de la publicaci??n

Iniciativa emprendedora y colaboración : un binomio que genera riqueza económica y social.

El artículo forma parte del monográfico de la revista dedicado a: la educación emprendedora: un reto plural

Un estudio sobre las potencialidades que genera en alumnos de secundaria el modelo de gestión mental aplicado a las fracciones.

Introducir modificaciones en el trabajo del aula en el área de Matemáticas para promover el aprendizaje, y lograr que los alumnos inhibidos en el contexto escolar lleguen a desarrollar sus potencialidades para aplicarlas en la vida cotidiana. Encontrar vías para lograr integrar las fracciones, los decimales y la recta numérica en el concepto más amplio de número racional, todo ello dentro del curriculum de la Enseñanza Secundaria Obligatoria. Poner en práctica en el aula situaciones de aprendizaje variadas que permitan ser analizadas, especialmente, los fenómenos de comprensión del conocimiento matemático. Observar si se producen variaciones en la comprensión del conocimiento de los números racionales, y valorar su opinión-actitud hacia las Matemáticas al aplicar un modelo didáctico de gestión mental. Alumnos de primero de BUP. En una primera parte se realiza un estudio de las investigaciones relacionadas con el tema y un análisis teórico de las cuestiones de investigación, posteriormente se elaboran los supuestos, objetivos e hipotesis. La opción metodológica que se adopta es la investigación-acción, por ser un modelo dentro de paradigma cualitativo que observa y estudia reflexiva y participativamente, una situación social. La aplicación en el aula del modelo de gestión mental facilita la introducción del concepto de número racional, proporciona significado a sus diferentes representaciones y facilita la recogida de información válida para el análisis de su comprensión conceptual.