10,012 research outputs found
Vocalização e comentários sobre as relacões de parentesco de Hypsiboas ericae (Amphibia; Hylidae)
The vocalizations of Hypsiboas ericae (Caramaschi & Cruz, 2000) are described and new information on the external morphology and osteology of the species are presented. H. ericae presents a bony spine in the prepolex and the individuals can present green or brown dorsal color, as other species of the Hypsiboas pulchellus (Duméril & Bibron, 1841) species group. The vocalizations of H. ericae are similar to the vocalizations of Hypsiboas bischoffi (Boulenger, 1887), Hypsiboas guentheri (Boulenger, 1886), and other species in the H. polytaenius (Cope, 1870 "1869") clade of the H. pulchellus species group, but some osteological aspects are different to those found in the majority of the species of this group.As vocalizações de Hypsiboas ericae (Caramaschi & Cruz, 2000) são descritas e novas informações sobre a morfologia externa e a osteologia da espécie são apresentadas. H. ericae apresenta prepólex terminando em um espinho ósseo e os indivíduos podem ter o colorido dorsal marrom ou verde, como outras espécies do grupo de Hypsiboas pulchellus (Duméril & Bibron, 1841). As vocalizações de H. ericae são similares às de Hypsiboas bischoffi (Boulenger, 1887), Hypsiboas guentheri (Boulenger, 1886) e às de outras espécies do clado de H. polytaenius (Cope, 1870 "1869") do grupo de H. pulchellus, mas alguns aspectos de sua osteologia são muito diferentes dos encontrados na maioria das espécies do grupo de H. pulchellus.FAPES
The Tunisian traditional rabbit breeding system versus the commercial system: an epidemiological perspective
[EN] Rabbit breeding is practiced in many hot climate countries and contributes in terms of agricultural activities to rural development. In Tunisia two different rabbit breeding systems can be identified - the "traditional" (an integrated free range and underground system) and the "commercial" (employing sheds and wire net cages) practice. 24 Tunisian rabbitries (10 traditional and 14 commercial) were included in an epidemiological study aimed at comparing the prevalence of pathogenic bacteria responsible for upper respiratory and digestive diseases in the two breeding systems. A total of 128 adult rabbits (mean age of 9.4 months) were tested using deep nasal and rectal swabs. Symptoms of nasal discharge and/or diarrhea were recorded. 281 bacterial strains were isolated in total, 138 in commercial and 143 in traditional farms. The bacteria most frequently isolated (61.2%) were Gram-positive strains, which included Streptococcus sp. (22.8%), coagulase negative Staphylococcus sp. (17.8%) and coagulase-positive Staphylococcus (17.4%) strains. Among the Gram-negative isolated bacteria, Escherichia coli was the most frequent (12.5%), followed by Proteus sp. (5.7%). The two Salmonella strains isolated were Salmonella bongori (found in the commercial system), and Salmonella typhimurium definitive phage-type (DT) 104 (found in the traditional farming system). The absence of Pasteurella multocida in the list of isolated bacteria may be directly correlated to the method of conserving the samples (storage at freezing temperature). The coagulase-positive Staphylococcus strains were frequently isolated (73.5%) from healthy rabbits, but seldom from rabbits with rhinitis (18.4%) or diarrhea (8.2%). Staphylococcus aureus strains were recovered at a higher rate in commercial farms (21%) in comparison with traditional (11.9%) farms. However, this difference was not statistically significant. Four Staphylococcus aureus strains, all belonging to commercial farms, proved positive when tested for enterotoxin production. The antimicrobial susceptibility of isolated Staphylococcus aureus strains was also investigated. Most of the antibiotics tested were very effective: the highest level of susceptibility was observed with enrofloxacin (100%). The low performance of Tunisian traditional rabbit rearing has been linked to the high mortality rate, which may possibly be due to the increased presence of pathogens at the rabbit flock level. However, this was not confirmed by the results of our study due to the fact that the bacterial contamination seems to be comparable in both the traditional and the commercial breeding systems.Belli, P.; Fontana, E.; Sommariva, M.; Scarpelli, L.; Ricci, C.; Luzi, F.; Haddad, B. (2008). The Tunisian traditional rabbit breeding system versus the commercial system: an epidemiological perspective. World Rabbit Science. 16(4). doi:10.4995/wrs.2008.617SWORD16
Isospin relaxation time in heavy-ion collisions at intermediate energies
Using an isospin-dependent transport model, we have studied the isospin and
momentum relaxation times in the heavy residues formed in heavy-ion collisions
at intermediate energies. It is found that only at incident energies below the
Fermi energy, chemical or thermal equilibrium can be reached before dynamical
instability is developed in the heavy residues. Also, the isospin relaxation
time is shorter (longer) than that for momentum at beam energies lower (higher)
than the Fermi energy.Comment: 8 pages Latex + 2 ps Figs.; Phys. Rev. C in pres
Historical dynamics of Batrachochytrium dendrobatidis in Amazonia
Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)The Amazon forest is known for its astonishing amphibian diversity, yet the potential distribution and underlying impacts of the most important amphibian pathogen is unknown for most of Amazonia. In this retrospective survey of preserved Leptodactylus frogs, collected over a 119 yr period, we used quantitative PCR to detect the fungal pathogen Batrachochytrium dendrobatidis (Bd) and performed spatial scan analyses to identify spatiotemporal clusters of Bd. We also quantified the potential effect of environmental factors on the likelihood of Bd occurrence and generated an updated suitability map for Bd in the Amazon that included our retrospective sampling. We detected Bd in lowland Amazon as early as 1935, in the state of Para, Brazil, and we found low prevalence (approximate to 3.8%) over time. We identified two statistically significant spatiotemporal clusters of Bd: a recent and narrow cluster in the Amazon River delta and a spatiotemporally broad cluster in the southern edge of Amazon and Brazilian savanna. Furthermore, we found an increase in Bd-positive samples in the southwestern Amazon after the 1990s, coinciding with reported amphibian declines in neighboring high elevation sites on Andean slopes of Peru. Spatial regressions indicated that higher human interference, higher precipitation, and lower temperatures were significant predictors of Bd occurrence. Environmental niche modeling predicted some narrow areas of suitable climates along the Amazon's periphery and generally low climatic suitability for Bd in the central Amazon; although, we found clusters of Bd-positive samples with unexpectedly high infection loads in areas of predicted low suitability. Our study indicates that accelerated human development may put Amazonian amphibians at risk from Bd introductions, and it highlights the potential need to monitor Bd dynamics near Amazonian port cities.The Amazon forest is known for its astonishing amphibian diversity, yet the potential distribution and underlying impacts of the most important amphibian pathogen is unknown for most of Amazonia. In this retrospective survey of preserved Leptodactylus fro3910954960CNQP - CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICOFAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULOConselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)312895/2014-3405285/2013-2302589/2013-92013/50741-7302518/2013-4We thank T. S. Jenkinson, and M. F. K. Becker for feedback on the manuscriptN. Pupin, A. Mesquita, E. Garcia, D. B. Delgado T. Carvalho, P. Mourao, A. F. R. Missassi, and L. F. Moreno for help with swabbing the specimens. Christopher J. Raxworthy, Da
The efficiency of indicator groups for the conservation of amphibians in the Brazilian Atlantic Forest
The adequate selection of indicator groups of biodiversity is an important aspect of the systematic conservation planning. However, these assessments differ in the spatial scale, in the methods used and in the groups considered to accomplish this task, which generally produces contradictory results. The quantification of the spatial congruence between species richness and complementarity among different taxonomic groups is a fundamental step to identify potential indicator groups. Using a constructive approach, the main purposes of this study were to evaluate the performance and efficiency of eight potential indicator groups representing amphibian diversity in the Brazilian Atlantic Forest. Data on the geographic range of amphibian species that occur in the Brazilian Atlantic Forest was overlapped to the full geographic extent of the biome, which was divided into a regular equal-area grid. Optimization routines based on the concept of complementarily were applied to verify the performance of each indicator group selected in relation to the representativeness of the amphibians in the Brazilian Atlantic Forest as a whole, which were solved by the algorithm"simulated annealing", through the use of the software MARXAN. Some indicator groups were substantially more effective than others in regards to the representation of the taxonomic groups assessed, which was confirmed by the high significance of data (F = 312.76; p < 0.01). Leiuperidae was considered as the best indicator group among the families analyzed, as it showed a good performance, representing 71% of amphibian species in the Brazilian Atlantic Forest (i.e. 290 species), which may be associated with the diffuse geographic distribution of its species. This study promotes understanding of how the diversity standards of amphibians can be informative for systematic conservation planning on a regional scale
Characterization of polymorphic microsatellite markers for the Neotropical leaf-frog Phyllomedusa burmeisteri and cross-species amplification
Twelve polymorphic tetranucleotide microsatellite loci were isolated and characterized for the leaf-frog Phyllomedusa burmeisteri, an endemic species of the Brazilian Atlantic forest. These loci were screened in 25 individuals from two populations of the Minas Gerais State (Carangola and Juiz de Fora). The number of alleles per locus ranged from 3 to 16 (mean = 8). Observed and expected heterozygosities ranged from 0.25 to 0.92 and 0.56 to 0.92, respectively. Evidence for both the presence of null alleles and Hardy-Weinberg equilibrium deviations were found in loci Phybu4, Phybu17, and Phybu21. Genotypic disequilibrium for each pair of loci across populations was not significant. Cross-species amplification was successful for 11 of the 12 developed loci for the sister-species, P. bahiana. These microsatellites will be important for future fine-scale population structure analyses
Injection of photoelectrons into dense argon gas
The injection of photoelectrons in a gaseous or liquid sample is a widespread
technique to produce a cold plasma in a weakly--ionized system in order to
study the transport properties of electrons in a dense gas or liquid. We report
here the experimental results of photoelectron injection into dense argon gas
at the temperatureT=142.6 K as a function of the externally applied electric
field and gas density. We show that the experimental data can be interpreted in
terms of the so called Young-Bradbury model only if multiple scattering effects
due to the dense environment are taken into account when computing the
scattering properties and the energetics of the electrons.Comment: 18 pages, 10 figures, figure nr. 10 has been redrawn, to be submitted
to Plasma Sources Science and Technolog
Variabilidade genética de isolados do fungo causador da Sigatoka- Amarela em bananeira no Estado da Bahia com o uso de SSR.
A bananeira assume importância econômica e social em todo o mundo, cultivada em mais de 130 países tropicais e subtropicais, principalmente por pequenos agricultores. O Brasil, em 2010 produziu 6,9 milhões de toneladas em uma área de 487 mil ha (FAO, 2012). Esta cultura apresenta importância na geração de empregos, sendo responsável pela renda de milhões de famílias. Embora este cenário seja bastante promissor, a maioria das variedades de bananeira disponível é suscetível à Sigatoka-amarela, causada pelo fungo Mycosphaerella musicola Leach, onde a aplicação sistemática de fungicidas ainda é a principal meio de controle.1 CD-ROM
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