Your browser doesn't support javascript.
loading
Montrer: 20 | 50 | 100
Résultats 1 - 8 de 8
Filtrer
Plus de filtres











Gamme d'année
1.
Rev. peru. biol. (Impr.) ; 31(1): e26851, Jan.-Mar. 2024. graf
Article de Espagnol | LILACS-Express | LILACS | ID: biblio-1565776

RÉSUMÉ

Resumen Se reporta por primera vez la presencia de Piptochaetium bicolor (Vahl) É. Desv. y Trichachne californica var. villosissima (Henrard) Wipff & Shaw para Perú, basada en colecciones realizadas en el ecosistema de formación de lomas costeras del departamento de Arequipa. Se presentan descripciones, fotografías, ilustraciones y una clave taxonómica para cada taxón.


Abstract The presence of Piptochaetium bicolor (Vahl) É. Desv. and Trichachne californica var. villosissima (Henrard) Wipff & Shaw are recorded for the first time from Peru, based upon collections made in the coastal lomas formations ecosystem of the department of Arequipa. Descriptions, photographs, illustrations and a taxonomic key are presented for each taxon.

2.
J Anim Ecol ; 86(2): 405-413, 2017 Mar.
Article de Anglais | MEDLINE | ID: mdl-28004849

RÉSUMÉ

Because a broad spectrum of resource use allows species to persist in a wide range of habitat types, and thus permits them to occupy large geographical areas, and because broadly distributed species have access to more diverse resource bases, the resource breadth hypothesis posits that the diversity of resources used by organisms should be positively related with the extent of their geographic ranges. We investigated isotopic niche width in a small radiation of South American birds in the genus Cinclodes. We analysed feathers of 12 species of Cinclodes to test the isotopic version of the resource breadth hypothesis and to examine the correlation between isotopic niche breadth and morphology. We found a positive correlation between the widths of hydrogen and oxygen isotopic niches (which estimate breadth of elevational range) and widths of the carbon and nitrogen isotopic niches (which estimates the diversity of resources consumed, and hence of habitats used). We also found a positive correlation between broad isotopic niches and wing morphology. Our study not only supports the resource breadth hypothesis but it also highlights the usefulness of stable isotope analyses as tools in the exploration of ecological niches. It is an example of a macroecological application of stable isotopes. It also illustrates the importance of scientific collections in ecological studies.


Sujet(s)
Écosystème , Passeriformes/anatomie et histologie , Passeriformes/physiologie , Animaux , Isotopes du carbone/analyse , Deutérium/analyse , Plumes/composition chimique , Amérique du Sud
3.
PhytoKeys ; (34): 1-13, 2014.
Article de Anglais | MEDLINE | ID: mdl-24596488

RÉSUMÉ

A synopsis of Plazia Ruiz & Pav. (Onoserideae, Asteraceae) is presented, including the description of a new species, Plazia robinsonii M.O.Dillon & Sagást., from a locality c. 20 kms west of Huamachuco, Department of La Libertad in northern Peru. It most closely resembles Plazia conferta Ruiz & Pav., a narrow endemic from central Peru some 450 km to the south; however, the latter species has larger leaves and smaller capitula. Plazia is a small genus of four species confined to the Andean Cordillera of Peru, Bolivia, Chile, and Argentina. A distribution map of the four species, an illustration of the new species, a photograph of the holotype, and a key to species are provided.


ResumenSe presenta una sinopsis del género Plazia Ruiz & Pav. (Onoserideae, Asteraceae), incluyendo la descripción de una nueva specie, Plazia robinsonii M.O.Dillon & Sagást., proveniente de una localidad c. 20 km al oeste de Huamachuco, Departamento de La Libertad, norte de Perú. Esta especie es similar a Plazia conferta Ruiz & Pav., un endemismo del centro de Perú, unos 450 km hacia el sur; sin emabrgo, esta última especie tiene hojas más grandes y capítulos más pequeños. Plazia es un género compuesto por cuatro especies restringidas a la Cordillera de los Andes de Perú, Bolivia, Chile y Argentina. Se inlcuye un mapa de distribución de las cuatro especies, una ilustración de la nueva especie, una fotografía del holotipo y una clave para las especies.

4.
Mol Phylogenet Evol ; 57(3): 1226-37, 2010 Dec.
Article de Anglais | MEDLINE | ID: mdl-20858548

RÉSUMÉ

The cosmopolitan Solanaceae contains 21 tribes and has the greatest diversity in South America. Hyoscyameae and Mandragoreae are the only tribes of this family distributed exclusively in Eurasia with two centers of diversity: the Mediterranean-Turanian (MT) region and the Tibetan Plateau (TP). In this study, we examined the origins and biogeographical diversifications of the two tribes based on the phylogenetic framework and chronogram inferred from a combined data set of six plastid DNA regions (the atpB gene, the ndhF gene, the rps16-trnK intergenic spacer, the rbcL gene, the trnC-psbM region and the psbA-trnH intergenic spacer) with two fossil calibration points. Our data suggest that Hyoscyameae and Mandragoreae each forms a monophyletic group independently derived from different New World lineages in the early Miocene. Phylogenetic relationships within both tribes are generally well resolved. All genera of Hyoscyameae are found to be monophyletic and they diversified in middle to late Miocene. At nearly the same time, Mandragoreae split into two clades, corresponding to the MT region and the TP region, respectively. Both the phylogenetic relationships and the estimated ages of Hyoscyameae and Mandragoreae support two independent dispersal events of their ancestors from the New World into Eurasia. After their arrivals in Eurasia, the two tribes diversified primarily in the MT region and in the TP region via multiple biogeographic processes including vicariance, dispersal, recolonization or being preserved as relicts, from the mid Miocene to the late Quaternary.


Sujet(s)
Évolution moléculaire , Phylogenèse , Solanaceae/génétique , Théorème de Bayes , ADN des plantes/génétique , Fossiles , Géographie , Fonctions de vraisemblance , Région méditerranéenne , Modèles génétiques , Plastes/génétique , Analyse de séquence d'ADN , Solanaceae/classification , Amérique du Sud
5.
Mol Phylogenet Evol ; 49(2): 561-73, 2008 Nov.
Article de Anglais | MEDLINE | ID: mdl-18722540

RÉSUMÉ

The phylogeny of Nolana (Solanaceae), a genus primarily distributed in the coastal Atacama and Peruvian deserts with a few species in the Andes and one species endemic to the Galápagos Islands, was reconstructed using sequences of four plastid regions (ndhF, psbA-trnH, rps16-trnK and trnC-psbM) and the nuclear LEAFY second intron. The monophyly of Nolana was strongly supported by all molecular data. The LEAFY data suggested that the Chilean species, including Nolana sessiliflora, the N. acuminata group and at least some members of the Alona group, are basally diverged, supporting the Chilean origin of the genus. Three well-supported clades in the LEAFY tree were corroborated by the SINE (short interspersed elements) or SINE-like insertions. Taxa from Peru are grouped roughly into two clades. Nolana galapagensis from the Galápagos Island is most likely to have derived from a Peruvian ancestor. The monophyly of the morphologically well-diagnosed Nolana acuminata group (N. acuminata, N. baccata, N. paradoxa, N. parviflora, N. pterocarpa, N. rupicola and N. elegans) was supported by both plastid and LEAFY data. Incongruence between the plastid and the LEAFY data was detected concerning primarily the positions of N. sessiliflora, N. galapagensis, taxa of the Alona group and the two Peruvian clades. Such incongruence may be due to reticulate evolution or in some cases lineage sorting of plastid DNA. Incongruence between our previous GBSSI trees and the plastid-LEAFY trees was also detected concerning two well-supported major clades in the GBSSI tree. Duplication of the GBSSI gene may have contributed to this incongruence.


Sujet(s)
Chloroplastes/génétique , Phylogenèse , Solanaceae/classification , Solanaceae/génétique , Théorème de Bayes , Chili , ADN des chloroplastes/génétique , Climat désertique , Évolution moléculaire , Marqueurs génétiques , Spéciation génétique , Introns , Modèles génétiques , Pérou , Éléments SINE
6.
J Pediatr ; 151(2): 140-4, 2007 Aug.
Article de Anglais | MEDLINE | ID: mdl-17643764

RÉSUMÉ

OBJECTIVE: To describe the presentation, management, and outcome of 43 cases of pneumococcal-associated hemolytic uremic syndrome (P-HUS). An increased incidence of P-HUS has been noted in the United Kingdom between January 1998 and May 2005. STUDY DESIGN: Cases with microangiopathic hemolytic anemia (Hb <10 g/dL with fragmented RBCs), thrombocytopenia (platelet count < 130 x 10(9)/L), acute renal impairment with oliguria and elevated plasma creatinine for age, confirmed or suspected pneumococcal infection and/or T-activation were included. RESULTS: The median age at presentation was 13 months (range, 5-39 months). Pneumococcus was identified in 34 of 43 cases; T-activation was identified in 36 of 37 cases. Twelve strains were serotyped: serotypes 3 (n = 2), 6A (n = 2), 12F (n = 1), 14 (n = 1), 19A (n = 6). Empyema was present in 23 of 35 pneumonia cases; 13 cases had confirmed (9) or suspected (4) pneumococcal meningitis; 36 cases required dialysis (median, 10 days; range, 2-240 days). The mortality rate was 11%, comprising 3 cases of meningitis, 1 case of sepsis and 1 case of pulmonary embolism at 8 months follow up while on dialysis. Follow-up data were available for 35 of 38 patients who survived (median follow-up period, 9 months; range, 1-63 months); of these, 10 patients had renal dysfunction, 1 patient was dialysis-dependent, 5 patients had hypertension and 8 patients had at least 1+ proteinuria on urinalysis. CONCLUSION: P-HUS has increased compared with historic surveys (0/288 in 1985-1988; 8/413 in 1997-2001, 43/315 in 1998-May 2005). Early mortality remains high (8-fold that of VTEC-induced HUS). Ten of 12 strains identified would not be covered by the PCV7 vaccine.


Sujet(s)
Syndrome hémolytique et urémique/diagnostic , Syndrome hémolytique et urémique/épidémiologie , Pneumonie à pneumocoques/diagnostic , Pneumonie à pneumocoques/épidémiologie , Répartition par âge , Antibactériens/usage thérapeutique , Enfant d'âge préscolaire , Études de cohortes , Comorbidité , Femelle , Syndrome hémolytique et urémique/thérapie , Humains , Incidence , Nourrisson , Mâle , Infections à pneumocoques/diagnostic , Infections à pneumocoques/traitement médicamenteux , Infections à pneumocoques/épidémiologie , Pneumonie à pneumocoques/traitement médicamenteux , Probabilité , Appréciation des risques , Indice de gravité de la maladie , Répartition par sexe , Taux de survie , Royaume-Uni/épidémiologie
7.
Arnaldoa ; 11(2): 29-35, dic. 2004. ilus, tab
Article de Espagnol | LIPECS | ID: biblio-1106324

RÉSUMÉ

Mientras colectábamos en remotas regiones al norte del Departamento de Ancash (Perú), descubrimos una nueva especie, Puya tyleriana, la cual describimos e ilustramos en el presente trabajo. Esta especie tiene una apariencia distintiva con inflorescencias paniculadas, abiertas, de más de un metro de longitud. Las flores son sostenidas por brácteas más grandes que los pedicelos, sépalos densamente blanco-lanosos, corolas purpúreas ya anteras ligeramente excertas.


While collecting in remote region of northern Department Ancash (Peru), we discovered a new species, Puya tyleriana, which we here describe and illustrate. This species has a distinctive appearance with open, paniculate inflorescences over a meter in length. The flowers are subtended by only half as long as the pedicels, the sepals are densely white-lanate, and the corollas are deep purple with exserted anthers.


Sujet(s)
Botanique , Bromeliaceae , Pérou
8.
J Exp Biol ; 207(Pt 3): 417-25, 2004 Jan.
Article de Anglais | MEDLINE | ID: mdl-14691089

RÉSUMÉ

The ability of orchid bees to generate vertical forces was evaluated using a load-lifting method that imposed asymptotically increasing loads during ascending flight, ultimately eliciting maximum forces while hovering. Among 11 orchid bee species varying by approximately an order of magnitude in body mass, the capacity to produce vertical forces expressed relative either to body weight or to flight muscle weight declined linearly with increased body mass. Allometric analysis of log-transformed data, by contrast, found maximum vertical force to scale isometrically with body mass, but also to exhibit a slightly negative allometry with respect to flight muscle mass. Maximum stroke amplitude at limiting loads averaged 140 degrees and was remarkably constant among species, a result consistent with anatomical constraints of the hymenopteran thorax on wing motions. By contrast, wing-beat frequencies during maximum performance declined with increasing body mass. Repeated lifting by individual bees reduced performance only when the number of consecutive lifts exceeded 15. Variation in linear mass density of the lifted load did not systematically alter performance estimates, although measurements on one species in two consecutive years at different thermal environments yielded significant differences in estimates of maximum force production. These findings suggest an adverse scaling of vertical force production at greater body mass even if flight muscle mass scales isometrically.


Sujet(s)
Abeilles/physiologie , Vol animal , Ailes d'animaux/physiologie , Animaux , Phénomènes biomécaniques , Constitution physique , Panama , Spécificité d'espèce , Enregistrement sur magnétoscope
SÉLECTION CITATIONS
DÉTAIL DE RECHERCHE