3,716 research outputs found
On the colour polymorphism of Philaenus spumarius (L.) (Homoptera, Cercopidae) in Portugal
Copyright © 1997 Museu de Zoologia.On the colour polymorphism of Philaenus spumarius (L) (Homoptera, Cercopidae) in Portugal.- A total of 7,967 specimens (4,354 males and 3,613 females) of the meadow spittlebug Philaenus spumarius (L) collected in three different habitats at Fontanelas (Sintra) were analysed in terms of the colour morph frequencies. Eleven different morphs were encountered: populi (POP), typicus (TYP), trilineatus (TRI), marginellus (MAR). lateralis (LAT). fIavicollis (FLA), gibbus (GIB), ustulatus (UST), quadrimaculatus (QUA), albomaculatus (ALB), and leucophthalmus (LOP). For males and in decreasing order of frequency the following morph groups and morphs proper were found: TYP group (95.38%). TRI group (3.70%), LCE group (0.85%), and LOP group (0.07%); and for females TYP group (88.79%). TRI group (4.01 %). MAR (3.32%). LOP group (1.88%), LCE group (1.74%), and LAT (0.25%). As expected, the TYP group (POP + TYP) was more frequent in males than in females (about 95% VS. 89%, respectively). Moreover, most melanic morphs were exclusively (MAR, LAT, ALB, and LOP) or better represented (FLA and QUA) in females than in males. Results also show that there appear to be differences regarding females among the three habitats studied, in spite of being practically contiguous. The coolest of all three habitats (a Pinus pinaster woodland with a shrub community dominated mostly by U1ex europaea) showed the highest frequencies of the melanic morphs. It is therefore suggested that among other factors, thermal melanism plays an important selective role in the colour polymorphism of the meadow spittlebug at Fontanelas
Estimando la riqueza de especies de artrópodos en los pastizales de las Azores: eficacia de los métodos de succión y las trampas de caída
Se han investigado las ventajas del uso combinado de técnicas de succión (Vortis) y trampas de caída, a la hora de estimar la riqueza de especies de artrópodos en pastizales antrópicos y seminaturales de tres islas oceánicas de las Azores de origen geológico reciente. Se ha comprobado, además, la capacidad de las trampas de caída y de succión para describir la composición faunística y la riqueza de especies según distintos grupos taxonómicos y ecológicos. Teniendo en cuenta el porcentaje de especies colectado sobre el total estimado, ambas técnicas de muestreo resultaron fiables en lo que se refiere a su eficacia, ofreciendo buenas estimas de la riqueza de especies de artrópodos. Usando los dos métodos a la vez, se obtuvieron valores de eficacia cercanos al 90% para algunos grupos taxonómicos. Las técnicas de succión o de caída por separado fueron fiables para estimar la riqueza de especies de artrópodos predadores (todas las especies) y arañas. Sin embargo, ambas técnicas son necesarias para conseguir estimaciones fiables en el caso de los grupos herbívoros. En términos de presencia-ausencia, los grupos que se alimentan de savia, los chupadores y los herbívoros masticadores mostraron diferentes patrones, con una proporción de colecta más alta en los primeros mediante las técnicas de succión, mientras que la mayoría de las especies masticadoras se pudieron colectar mediante las trampas de caída. Un patrón similar fue obtenido en el caso de las arañas, en donde las especies tejedoras fueron colectadas solo gracias a las técnicas de succión, mientras que la mayoría del resto de las especies se capturaron gracias al uso de trampas de caída. Se concluye que estos dos métodos de colecta deben considerarse complementarios y no alternativos. Por tanto, en estudios realizados en pastizales y sistemas agrícolas, se recomienda el uso simultáneo de ambas técnicas a fin de obtener estimas fiables de la riqueza de especies y la composición taxonómica de artrópodos
Canopy habitat area effect on the arthropod species densities in the Azores: pondering the contribution of tourist species and other life histories
"[…]. We performed a PIAR examining how plant cover area and plant crown structure influence the densities of arthropods in the canopies of one specific island, comparing various distinct natural reserves. Species densities were measured for two functional insect herbivore guilds (sap-sucking and leaf-chewing insects) and the most common predatory assembly in this system (spiders) in three different ways: i) the average number of specimens per plant; ii) the average number of specimens per transect, providing both fine and broad scales of species abundance (see Methods); iii) absolute numbers per reserve. Moreover, we investigated common versus scarce arthropod species distributions between various plant species. […]" (da Introdução)Fundação para a Ciência e a Tecnologia, Portugal
Two Superconducting Phases in CeRh_1-xIr_xIn_5
Pressure studies of CeRh_1-xIr_xIn_5 indicate two superconducting phases as a
function of x, one with T_c >= 2 K for x < 0.9 and the other with T_c < 1.2 K
for x > 0.9. The higher T_c phase, phase-1, emerges in proximity to an
antiferromagnetic quantum-critical point; whereas, Cooper pairing in the lower
T_c phase-2 is inferred to arise from fluctuations of a yet to be found
magnetic state. The T-x-P phase diagram of CeRh_1-xIr_xIn_5, though
qualitatively similar, is distinctly different from that of
CeCu_2(Si_1-xGe_x)_2.Comment: 5 pages, 3 figure
Electronic structure, optical and magnetic properties of CoFeGe Heusler alloy films
Optical properties of ferromagnetic half-metallic full-Heusler CoFeGe
alloy are investigated experimentally and theoretically. CoFeGe thin
films were obtained by DC magnetron sputtering and show the saturation
magnetization at =10 K of 5.6 /f.u., close to the value
predicted by the Slater-Pauling rule. First-principles calculations of the
electronic structure and the dielectric tensor are performed using the
full-potential linearized-augmented-plane-wave method in the generalized
gradient (GGA) and GGA+U approximations. The measured interband optical
conductivity spectrum for the alloy exhibits a strong absorption band in the 1
- 4 eV energy range with pronounced fine structure, which agrees well with the
calculated half-metallic spectrum of the system, suggesting a near perfect
spin-polarization in the material.Comment: 6 pages, 9 figure
Influência da época do ano e das diferentes formas de aplicação de ácido naftaleno acético (ANA) no enraizamento de Mikania micrantha Kunth.
Mikania micrantha Kunth é uma espécie nativa do Brasil, heliófila e de hábito rasteiro. É amplamente difundida na medicina popular e potencialmente utilizada na recuperação de áreas degradadas. O objetivo deste trabalho foi verificar a influência de diferentes formulações e vias de aplicação de ácido naftaleno acético (NAA) no enraizamento de estacas caulinares de Mikania micrantha Kunth coletadas nas quatro estações do ano. Estacas herbáceas provenientes de plantas matrizes nativas da região de Colombo - Paraná foram coletadas na primavera/2002, verão/2003, outono/2003 e inverno/2003, confeccionadas com 10 cm de comprimento e uma folha cortada pela metade mantida no ápice, desinfestadas e submetidas aos seguintes tratamentos (T): T, (Omg Kg-lANA), T2 (5000 mg Kg-l ANA), T3 (5000 mg Kg-1ANA- RAIZON 05@),T4 (5000 mg L-I ANA), T, (O mg L-' ANA) e Te (água). O plantio foi realizado em tubetes de polipropileno (55 crn-) contendo vermiculita de granulometria média, sendo as estacas mantidas em casa-devegetação com nebulização intermitente. Após 20 dias foram avaliadas as seguintes características: porcentagem de estacas enraizadas, número e comprimento das três maiores raízes por estaca, porcentagem de estacas vivas (sem raiz e sem calos) e porcentagem de estacas mortas. A análise estatística constou de um delineamento inteiramente casualizado (DIC) composto por seis tratamentos com quatro repetições de 24 estacas por parcela. A espécie foi considerada de fácil enraizamento, apresentando as maiores porcentagens na primavera, verão e outono (superiores a 86%), dispensando o uso de regulador vegetal para a indução radicial
Normalization strategies for real-time expression data in Chlamydia trachomatis
Since Chlamydia trachomatis is a genetically non-tractable pathogen, transcriptomics assumes a fundamental role for the better understanding of its biology. However, the suitability of endogenous controls for normalization of transcriptomic data in this bacterium still needs validation. We aimed to assess the stability of 10 genes for their potential use as endogenous controls in qPCR at both normal and stress (antibiotic treatment) growth conditions throughout the developmental cycle of three strains with different cell-appetence. Normalization was performed using the quantified bacterial genomes. We also tested the applicability of two widely used softwares (geNorm and Normfinder) to our data. For all strains, we found that 16SrRNA was the most stably expressed gene throughout the normal developmental cycle, but it was highly unstable under antibiotic exposure, suggesting prudence when using ribosomal genes as endogenous controls in expression experiments involving stress environments. The geNorm and Normfinder algorithms revealed contrasting results and seem inappropriate for the selected pool of genes. Considering the multiplicity of experimental conditions, there should be an in loco validation of endogenous controls, where 16SrRNA appears to be in the front line. Alternatively, normalization of expression data against genomic DNA, which is less influenced by experimental constraints (especially relevant for intracellular organisms) and stress conditions, likely constitutes a good option. The present study constitutes the first evaluation of putative endogenous controls for real-time expression assays in C. trachomati
Spatial scaling of species abundance distributions
Copyright © 2012 The Authors. Ecography © 2012 Nordic Society Oikos.Species abundance distributions are an essential tool in describing the biodiversity of ecological communities. We now know that their shape changes as a function of the size of area sampled. Here we analyze the scaling properties of species abundance distributions by using the moments of the logarithmically transformed number of individuals. We find that the moments as a function of area size are well fitted by power laws and we use this pattern to estimate the species abundance distribution for areas larger than those sampled. To reconstruct the species abundance distribution from its moments, we use discrete Tchebichef polynomials. We exemplify the method with data on tree and shrub species from a 50 ha plot of tropical rain forest on Barro Colorado Island, Panama. We test the method within the 50 ha plot, and then we extrapolate the species abundance distribution for areas up to 5 km2. Our results project that for areas above 50 ha the species abundance distributions have a bimodal shape with a local maximum occurring for the singleton classes and that this maximum increases with sampled area size
First records of Tarentola mauritanica (Linnaeus, 1758) (Reptilia; Gekkonidae) in the Azores
The Moorish gecko Tarentola mauritanica
(Linnaeus, 1758) is a widespread species native to the Mediterranean region from southern France to Greece and northern Africa (Loveridge 1947; Martínez-Rica 1997; Hódar 2002; Perera et al. 2008, 2010; Plezeguelos et al. 2008). It has recently been reported as living and breeding in
California (Marhdt 1998) and also as an
introduced species in Madeira (Báez & Biscoito 1993). Tarentola mauritanica is paraphyletic with respect to T. angustimentalis Steindachner, 1891,
a Canary Islands endemic (Harris et al. 2004a). Here we report new occurrences of the Moorish gecko on Terceira Island, Azores archipelago, and 3 other occurrences on the islands of São Miguel and Faial. The possibility of an already established breeding population is discussed
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