18 research outputs found
NEOTROPICAL XENARTHRANS: a data set of occurrence of xenarthran species in the Neotropics
Xenarthrans â anteaters, sloths, and armadillos â have essential functions for ecosystem maintenance, such as insect control and nutrient cycling, playing key roles as ecosystem engineers. Because of habitat loss and fragmentation, hunting pressure, and conflicts with 24 domestic dogs, these species have been threatened locally, regionally, or even across their full distribution ranges. The Neotropics harbor 21 species of armadillos, ten anteaters, and six sloths. Our dataset includes the families Chlamyphoridae (13), Dasypodidae (7), Myrmecophagidae (3), Bradypodidae (4), and Megalonychidae (2). We have no occurrence data on Dasypus pilosus (Dasypodidae). Regarding Cyclopedidae, until recently, only one species was recognized, but new genetic studies have revealed that the group is represented by seven species. In this data-paper, we compiled a total of 42,528 records of 31 species, represented by occurrence and quantitative data, totaling 24,847 unique georeferenced records. The geographic range is from the south of the USA, Mexico, and Caribbean countries at the northern portion of the Neotropics, to its austral distribution in Argentina, Paraguay, Chile, and Uruguay. Regarding anteaters, Myrmecophaga tridactyla has the most records (n=5,941), and Cyclopes sp. has the fewest (n=240). The armadillo species with the most data is Dasypus novemcinctus (n=11,588), and the least recorded for Calyptophractus retusus (n=33). With regards to sloth species, Bradypus variegatus has the most records (n=962), and Bradypus pygmaeus has the fewest (n=12). Our main objective with Neotropical Xenarthrans is to make occurrence and quantitative data available to facilitate more ecological research, particularly if we integrate the xenarthran data with other datasets of Neotropical Series which will become available very soon (i.e. Neotropical Carnivores, Neotropical Invasive Mammals, and Neotropical Hunters and Dogs). Therefore, studies on trophic cascades, hunting pressure, habitat loss, fragmentation effects, species invasion, and climate change effects will be possible with the Neotropical Xenarthrans dataset
Erwinia chrysanthemi: pectolytic bacterium causing soft rot outbreaks of arracacha in Brazil Erwinia chrysanthemi: bactĂ©ria pectolĂtica envolvida na "mela" da mandioquinha-salsa no Brasil
The objetive of this work was to identify the pectolytic bacteria associated with soft rot of arracacha roots in Brazil. From 1998 to 2001, 227 isolates of Erwinia spp. were obtained from arracacha roots and identified by biochemical and physiological tests (pectolytic activity, lecithinase, a-methyl glucoside, phosphatase, erythromycin sensivity, growth at 37ºC). Of these isolates, 89.9% were identified as E. chrysanthemi (Ech), 9.7% as E. carotovora subsp. carotovora (Ecc) and 0.5% as E. carotovora subsp. atroseptica. The identity of seventeen out of twenty representative isolates of Ech and Ecc was confirmed by PCR (primers '149f', 'L1r', 'ADE1', 'ADE2').<br>O objetivo deste trabalho foi identificar as bactĂ©rias pectolĂticas envolvidas na podridĂŁo-mole de raĂzes de mandioquinha-salsa no Brasil. De 1998 a 2001, 227 isolados de Erwinia spp. foram obtidos de raĂzes de mandioquinha-salsa e identificados por testes bioquĂmicos e fisiolĂłgicos (atividade pectolĂtica, lecitinase, a-methyl glucosĂdeo, fosfatase, sensibilidade Ă eritromicina, crescimento a 37ºC). Destes isolados, 89,9% foram identificados como E. chrysanthemi (Ech), 9,7% como E. carotovora subsp. carotovora (Ecc) e somente 0,5% como E. carotovora subsp. atroseptica. A identidade de 20 isolados representativos de Ech e Ecc foi confirmada por PCR (primers '149f', 'L1r', 'ADE1', 'ADE2'), com exceção de dois isolados de Ech e um de Ecc
Doenças da mandioquinha-salsa e sua situação atual no Brasil Present situation of arracacha (Arracacia xanthorrhiza) diseases in Brazil
Este artigo tem como objetivo principal relatar as doenças registradas para a mandioquinha-salsa atĂ© a data presente e descrever sua situação atual no PaĂs. Na literatura, foram registrados para a cultura 27 gĂȘneros de fungos, trĂȘs de bactĂ©rias, doze de nematĂłides e cinco espĂ©cies de vĂrus. Destes, jĂĄ foram relatados no Brasil treze fungos, e todos nematĂłides e bactĂ©rias, enquanto nenhum vĂrus foi oficialmente registrado, embora jĂĄ tenham sido observadas plantas com sintomas tĂpicos de viroses a campo. A maior parte dos registros estĂŁo na forma de resumos, capĂtulos de livros ou publicaçÔes genĂ©ricas, desprovidos de uma sĂ©rie de dados relevantes, como provas de patogenicidade, importĂąncia da doença, perdas, identificação mais acurada, entre outras. A cultura da mandioquinha-salsa ainda Ă© tida como rĂșstica, sendo poucas as doenças consideradas limitantes. O nematĂłide das galhas (Meloidogyne spp.) e a podridĂŁo-mole pĂłs-colheita causada por Erwinia spp. sĂŁo os principais problemas atualmente, e causam perdas significativas. TambĂ©m ocorrem com muita frequĂȘncia manchas foliares causadas por Septoria, Cercospora e Xanthomonas campestris pv. arracaciae, e em algumas regiĂ”es podridĂŁo de plantas a campo causadas por Sclerotinia sclerotiorum e Sclerotium rolfsii. Como nĂŁo existe nenhum produto quĂmico oficialmente registrado para a mandioquinha-salsa no MinistĂ©rio da Agricultura, PecuĂĄria e Abastecimento, as medidas de controle passĂveis de recomendação incluem açÔes preventivas, como o uso de material propagativo sadio (preferencialmente mudas prĂ©-enraizadas de origem conhecida), a adoção de rotação de culturas, a eliminação de plantas ou partes doentes, e a adubação e a irrigação adequadas. O estudo sistematizado das doenças e o registro cuidadoso de surtos ou novas enfermidades para a cultura sĂŁo importantes para subsidiar futuras medidas de controle.<br>The diseases of arracacha that have already been recorded are described and their current situation in Brazil is discussed. Since its introduction in 1900-1910, arracacha has been considered a non-demanding crop, presenting some minor disease problems, especially when compared to other vegetable crops. Many of the recorded arracacha diseases in Brazil and other Latin American countries are poorly described, for there is hardly any information about pathogenicity tests, pathogen identity, crop losses and environmental conditions affecting diseases. Worldwide, 27 genera of fungi, three of bacteria, nine of nematodes and five species of viruses have been recorded. Of these, thirteen fungi and all bacteria and nematodes were recorded in Brazil. So far, no virus has been recorded, although virus-like symptoms have been observed. The most important diseases are the root knot, caused by Meloidogyne spp., and the postharvest soft rot caused by Erwinia spp. Commonly occurring diseases are leaf spots caused by Septoria spp., Cercospora spp. and Xanthomonas campestris pv. arracaciae, as well as plant rots caused by Sclerotium rolfsii and Sclerotinia sclerotiorum. Viruses could become of great importance since this crop is vegetatively propagated, and part of the plantlets are now being produced in nurseries by a new technique (pre-rooting) and then disseminated to different areas throughout Brazil. As there is no pesticide officially registered for this crop in Brazil, preventive measures of control must be used, such as crop rotation, suitable fertilization and irrigation, and removal and destruction of diseased plants. Arracacha seems to be suitable for organic cropping systems, since few diseases are considered limitant
Excess of charged over neutral meson production in high-energy collisions of atomic nuclei
Collisions of atomic nuclei at relativistic velocities produce new particles, predominantly mesons containing one valence quark and one valence anti-quark. These particles are produced in strong interactions, which preserve an approximate symmetry between up () and down () quarks. In the case of meson production, if this symmetry were exact, it would result in equal numbers of charged ( and ) and neutral ( and ) mesons in the final state. In this Letter, we report a measurement of the relative abundance of charged over neutral meson production in collisions of argon and scandium nuclei at a center-of-mass energy of 11.9~GeV per nucleon pair. We find that production of and mesons at mid-rapidity displays a significant excess of relative to that of the neutral mesons. The origin of this unexpected excess remains to be elucidated.Collisions of atomic nuclei at relativistic velocities produce new particles, predominantly mesons containing one valence quark and one valence anti-quark. These particles are produced in strong interactions, which preserve an approximate symmetry between up () and down () quarks. In the case of meson production, if this symmetry were exact, it would result in equal numbers of charged ( and ) and neutral ( and ) mesons in the final state. In this Letter, we report a measurement of the relative abundance of charged over neutral meson production in collisions of argon and scandium nuclei at a center-of-mass energy of 11.9~GeV per nucleon pair. We find that production of and mesons at mid-rapidity displays a significant excess of relative to that of the neutral mesons. The origin of this unexpected excess remains to be elucidated
Excess of charged over neutral meson production in high-energy collisions of atomic nuclei
International audienceCollisions of atomic nuclei at relativistic velocities produce new particles, predominantly mesons containing one valence quark and one valence anti-quark. These particles are produced in strong interactions, which preserve an approximate symmetry between up () and down () quarks. In the case of meson production, if this symmetry were exact, it would result in equal numbers of charged ( and ) and neutral ( and ) mesons in the final state. In this Letter, we report a measurement of the relative abundance of charged over neutral meson production in collisions of argon and scandium nuclei at a center-of-mass energy of 11.9~GeV per nucleon pair. We find that production of and mesons at mid-rapidity displays a significant excess of relative to that of the neutral mesons. The origin of this unexpected excess remains to be elucidated
Measurements of higher-order cumulants of multiplicity and net-electric charge distributions in inelastic proton-proton interactions by NA61/SHINE
International audienceThis paper presents the energy dependence of multiplicity and net-electric charge fluctuations in interactions at beam momenta 20, 31, 40, 80, and 158 GeV/. Results are corrected for the experimental biases and quantified with the use of cumulants and factorial cumulants. Data are compared with the Epos1.99 and FTFP-BERT model predictions
Measurements of higher-order cumulants of multiplicity and net-electric charge distributions in inelastic proton-proton interactions by NA61/SHINE
This paper presents the energy dependence of multiplicity and net-electric charge fluctuations in interactions at beam momenta 20, 31, 40, 80, and 158 GeV/. Results are corrected for the experimental biases and quantified with the use of cumulants and factorial cumulants. Data are compared with the Epos1.99 and FTFP-BERT model predictions