532 research outputs found
Disparate dispersal limitation in Geomalacus slugs unveiled by the shape and slope of the geneticâspatial distance relationship
Longâterm dispersal ability is a key speciesâ trait constraining species ranges and thus largeâscale biodiversity patterns. Here we infer the longâterm dispersal abilities of three Geomalacus (Gastropoda, Pulmonata) species from their rangeâwide geneticâspatial distance relationships. This approach follows recent advances in statistical modelling of the analogous pattern at the community level: the distance decay in assemblage similarity. While linear relationships are expected for species with high longâterm dispersal abilities, asymptotic relationships are expected for those with more restricted mobility. We evaluated three functional forms (linear, negative exponential and powerâlaw) for the relationship between genetic distance (computed from mitochondrial cox1 sequences, nâ=â701) and spatial distance. Range fragmentation at present time and at the Last Glacial Maximum was also estimated based on the projection of climatic niches. The powerâlaw function best fit the relationship between genetic and spatial distances, suggesting strong dispersal limitation and longâterm population isolation in all three species. However, the differences in slope and explained variance pointed to disparities in dispersal ability among these weak dispersers. Phylogeographic patterns of Geomalacus species are thus largely driven by the same major process (i.e. dispersal limitation), operating at different strengths. This strong dispersal limitation results in geographic clustering of genetic diversity that makes these species highly vulnerable to genetic erosion due to climate changThe authors were supported by the Spanish Ministry of Economy and Competitiveness and the European Regional Development Fund (ERDF) through grant CGL2016â76637âP and fellowship IJCIâ2014â20881 to CGâRS
Deformed Skyrme Crystals
The Skyrme crystal, a solution of the Skyrme model, is the lowest
energy-per-charge configuration of skyrmions seen so far. Our numerical
investigations show that, as the period in various space directions is changed,
one obtains various other configurations, such as a double square wall, and
parallel vortex-like solutions. We also show that there is a sudden "phase
transition" between a Skyrme crystal and the charge 4 skyrmion with cubic
symmetry as the period is gradually increased in all three space directions.Comment: 13 pages, 6 figures. To be published in JHE
Valence Quark Distribution in A=3 Nuclei
We calculate the quark distribution function for 3He/3H in a relativistic
quark model of nuclear structure which adequately reproduces the nucleon
approximation, nuclear binding energies, and nuclear sizes for small nuclei.
The results show a clear distortion from the quark distribution function for
individual nucleons (EMC effect) arising dominantly from a combination of
recoil and quark tunneling effects. Antisymmetrization (Pauli) effects are
found to be small due to limited spatial overlaps. We compare our predictions
with a published parameterization of the nuclear valence quark distributions
and find significant agreement.Comment: 18pp., revtex4, 4 fig
First cases of gynandromorphism in Phlebotomus perniciosus Newstead, 1911 (Diptera, Psychodidae, Phlebotominae)
Two gynandromorphic specimens of Phlebotomus perniciosus Newstead, 1911 are described and illustrated for the first time The specimens were collected in the Northeast of the Iberian Peninsula (Spain)
Validez y fiabilidad de un instrumento para la valoraciĂłn de la entrevista clĂnica en mĂ©dicos residentes de medicina de familia: el cuestionario GATHA-RES
ObjetivoComprobar la validez de contenido, la consistencia interna y la fiabilidad intraobservador de un cuestionario para la evaluaciĂłn de la comunicaciĂłn mĂ©dico-paciente de los residentes de medicina de familia.DiseñoEstudio observacional, de validaciĂłn de un instrumento de medida.EmplazamientoNivel de atenciĂłn primaria. Unidades docentes de medicina de familia y comunitaria.PoblaciĂłn de estudioPara el anĂĄlisis de validez, 25 mĂ©dicos residentes de medicina familiar y comunitaria. Para el anĂĄlisis de fiabilidad, 48 mĂ©dicos de la misma especialidad.Mediciones e intervencionesPara la construcciĂłn del cuestionario, se partiĂł de una versiĂłn (GATHA-BASE), compuesta por 42 Ătems seleccionados por un panel compuesto por 60 mĂ©dicos de familia. Para la validez de contenido, se utilizaron 68 encuentros clĂnicos con pacientes simulados, que fueron videograbados y evaluados. La validez de contenido del cuestionario se estudiĂł mediante un anĂĄlisis factorial, y para medir su consistencia interna se calcularon los coeficientes alfa de Cronbach. La fiabilidad intraobservador de la versiĂłn GATHA-RES fue evaluada mediante los Ăndices kappa y los coeficientes de correlaciĂłn intraclase.ResultadosObtuvimos una versiĂłn del GATHA-RES con 27 Ătems. El anĂĄlisis factorial revelĂł la existencia de 9 factores: «empatĂa», «anamnesis», «bidireccionalidad», «negociaciĂłn», «informaciĂłn», «miscelĂĄnea 1», «miscelĂĄnea 2» y «centrado en el paciente», que mostraron una buena correlaciĂłn con los contenidos teĂłricos y formales del cuestionario original (inicialmente agrupados en 3 secciones: actitudes, tareas comunicacionales y habilidades). Todos los coeficientes de correlaciĂłn intraclase presentaron cifras â„ 0,90.ConclusionesEl cuestionario GATHA-RES es un instrumento vĂĄlido y fiable que puede ser usado para la evaluaciĂłn de las habilidades comunicacionales de los mĂ©dicos de familia en formaciĂłn.ObjectiveTo check the validity of content, the internal consistency and the intra-observer reliability of a questionnaire to evaluate the doctor-patient communication of family medicine residents.DesignObservation study, to validate a measurement instrument.SettingPrimary care. Family and community medicine teaching units.Study populationFor the validity analysis: 25 family and community medicine residents. For the reliability analysis: 48 doctors in the same speciality.Measurements and interventionsThe questionnaire was constructed on the basis of a version (GATHABASE) composed of 42 items selected by a panel of 60 general practitioners. For content validity, 68 clinical encounters with simulated patients, video-recorded and evaluated, were used. The questionnaire's validity content was studied through a factorial analysis. To measure its internal consistency, Cronbach's alpha coefficients were calculated. Intra-observer reliability of the GATHA-RES version was evaluated through the kappa indexes and the intra-class correlation coefficients.ResultsWe obtained a version of the GATHA-RES with 27 items. The factorial analysis revealed that there were 9 factors («empathy», «anamnesis», «two-way communication», «negotiation», «information», «miscellaneous 1», «miscellaneous 2» and «patient-focused») which showed close correlation with the theoretical and formal contents of the original questionnaire (originally grouped in three sections: attitudes, communication tasks and skills). All the intraclass correlation coefficients had figures â„ 0.90.ConclusionsThe GATHA-RES questionnaire is a valid and reliable instrument that can be used for evaluating the communication skills of general practitioners in training
Hypocotyl Transcriptome Reveals Auxin Regulation of Growth-Promoting Genes through GA-Dependent and -Independent Pathways
Many processes critical to plant growth and development are regulated by the hormone auxin. Auxin responses are initiated through activation of a transcriptional response mediated by the TIR1/AFB family of F-box protein auxin receptors as well as the AUX/IAA and ARF families of transcriptional regulators. However, there is little information on how auxin regulates a specific cellular response. To begin to address this question, we have focused on auxin regulation of cell expansion in the Arabidopsis hypocotyl. We show that auxin-mediated hypocotyl elongation is dependent upon the TIR1/AFB family of auxin receptors and degradation of AUX/IAA repressors. We also use microarray studies of elongating hypocotyls to show that a number of growth-associated processes are activated by auxin including gibberellin biosynthesis, cell wall reorganization and biogenesis, and others. Our studies indicate that GA biosynthesis is required for normal response to auxin in the hypocotyl but that the overall transcriptional auxin output consists of PIF-dependent and -independent genes. We propose that auxin acts independently from and interdependently with PIF and GA pathways to regulate expression of growth-associated genes in cell expansion
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