80 research outputs found

    Restoration and Monitoring of the River Otter Population in Iowa

    Get PDF
    Northern river otters (Lontra canadensis) were widespread in North America at the time of European settlement. However, river otters were extirpated from most of Iowa in the early 1900s due to habitat degradation and unregulated harvest. In 1985, the Iowa Department of Natural Resources began an effort to restore the river otter population throughout the state, including a pilot study of survival to determine if establishment was feasible. Annual survival was estimated to be 86% during the pilot study. River otters dispersed an average of about 11 km from the point of release and exhibited habitat use typical for the species. Based on the successful pilot study, 261 river otters were released in the state of Iowa from 1986-2001. More recently we examined the age structure and reproductive effort of 81 river otters (43 females and 38 males) collected in Iowa from 1999-2001 to document the characteristics of the reestablished population. We found that 41% of the otters sampled were juveniles, 38% were yearlings and 21% were adults. Fifty-five percent of all female otters were pregnant, and 80% of adult females were pregnant. We observed a mean of 2.9 corpora lutea/female and calculated that female’s ≥ 1 year old could potentially produce an average 5.7 female offspring during an average life span. Based on the widespread distribution, healthy reproductive characteristics, and high survival rates it is feasible that a limited harvest of river otter could be implemented in Iowa

    Floral gene resources from basal angiosperms for comparative genomics research

    Get PDF
    BACKGROUND: The Floral Genome Project was initiated to bridge the genomic gap between the most broadly studied plant model systems. Arabidopsis and rice, although now completely sequenced and under intensive comparative genomic investigation, are separated by at least 125 million years of evolutionary time, and cannot in isolation provide a comprehensive perspective on structural and functional aspects of flowering plant genome dynamics. Here we discuss new genomic resources available to the scientific community, comprising cDNA libraries and Expressed Sequence Tag (EST) sequences for a suite of phylogenetically basal angiosperms specifically selected to bridge the evolutionary gaps between model plants and provide insights into gene content and genome structure in the earliest flowering plants. RESULTS: Random sequencing of cDNAs from representatives of phylogenetically important eudicot, non-grass monocot, and gymnosperm lineages has so far (as of 12/1/04) generated 70,514 ESTs and 48,170 assembled unigenes. Efficient sorting of EST sequences into putative gene families based on whole Arabidopsis/rice proteome comparison has permitted ready identification of cDNA clones for finished sequencing. Preliminarily, (i) proportions of functional categories among sequenced floral genes seem representative of the entire Arabidopsis transcriptome, (ii) many known floral gene homologues have been captured, and (iii) phylogenetic analyses of ESTs are providing new insights into the process of gene family evolution in relation to the origin and diversification of the angiosperms. CONCLUSION: Initial comparisons illustrate the utility of the EST data sets toward discovery of the basic floral transcriptome. These first findings also afford the opportunity to address a number of conspicuous evolutionary genomic questions, including reproductive organ transcriptome overlap between angiosperms and gymnosperms, genome-wide duplication history, lineage-specific gene duplication and functional divergence, and analyses of adaptive molecular evolution. Since not all genes in the floral transcriptome will be associated with flowering, these EST resources will also be of interest to plant scientists working on other functions, such as photosynthesis, signal transduction, and metabolic pathways

    Identification of Chromosomes with Secondary Constrictions in \u3ci\u3eMelilotus\u3c/i\u3e Species

    Get PDF
    Secondary constrictions were determined in one chromosome pair in the complements of M. infesta, M. macrocarpa, M. italica (subgenus Micromeliotus), and M. alba and M. officinalis (subgenus Meliotus). The karyotypes of M. infesta and M. macrocarpa were found to be similar. Chromosomes of M. italica were larger than the chromosomes of the other four Melilotus species. The chromosome size in M. italica suggests the presence of large chromosomes in an ancestral or pro-Melilotus prototype. The chromosomes with satellites of M. infesta and M. macrocarpa appear to differ in morphology from the satellite chromosomes of M. alba and M. officinalis by a paracentric inversion. The morphology of the satellite chromosomes in M. italica is thought to represent a more primitive type than in the other Meliotus species studied

    Ambiente de trabajo cooperativo en internet para la educación en valores

    Get PDF
    TesisEl presente trabajo de investigación que lleva por título "AMBIENTE DE TRABAJO COOPERATIVO EN INTERNET PARA LA EDUCACION EN VALORES" responde a la necesidad de desarrollar nuevas formas de planificar y desarrollar la educación, de manera que se promueva la participación sincrónica y asincrónica entre tos sujetos que no se encuentran físicamente en el mismo lugar, ni en las mismas coordenadas temporales. El objetivo fue desarrollar un Ambiente de Trabajo Cooperativo en Internet para la educación en valores utilizando la Metodología Orientada a objetos y la Filosofía de Software Libre propiciando básicamente la reunión síncrona y. asíncrona para los miembros de la Federación de Familias para la Paz Mundial. Se ha utilizado Moodle, el cual es un . proyecto en desarrollo diseñado para dar soporte a un marco de educación social . constructivista. Esta herramienta se ha integrado al Ambiente de Trabajo Cooperativo principalmente para diseñar diferentes cursos en diferentes niveles y a diferentes usuarios. Tambíén se ha empleado los indicadores de calidad del Estándar IS0-9126, tales como funcionalidad, fiabilidad, usabilidad, eficiencia, mantenibilidad y portabilidad en una escala de 1 a 5 puntos. Se llega a la conclusión de que los ambientes de trabajo cooperativos para la educación en valores, permite mejorar el proceso de educación básicamente en la comunicación de los miembros de la Federación de Familias para la Paz Mundial cumpliendo con aprobar el estándar de calidad de software ISO 9126 en el que se observa que un 60% de los profesionales de cada país dicen que el Ambiente de Trabajo Cooperativo es bueno y un 10% afirma que es muy bueno. Palabras Claves: Ambiente de trabajo cooperativo, valores, internet, educació

    Geographically extensive hybridization between the forest trees American butternut and Japanese walnut

    No full text
    We investigate the question of naturally occurring interspecific hybrids between two forest trees: the native North American butternut (Juglans cinerea L.) and the introduced Japanese walnut (Juglans ailantifolia Carrière). Using nuclear and chloroplast DNA markers, we provide evidence for 29 F1 and 22 advanced generation hybrids in seven locations across the eastern and southern range of the native species. Two locations show extensive admixture (95% J. ailantifolia and hybrids) while other locations show limited admixture. Hybridization appears to be asymmetrical with 90.9 per cent of hybrids having J. ailantifolia as the maternal parent. This is, to our knowledge, the first genetic data supporting natural hybridization between these species. The long-term outcome of introgression could include loss of native diversity, but could also include transfer of useful traits from the introduced species
    corecore