4,315 research outputs found
Avaliação das sementes do nim (Azadirachta indica) no controle de nematódeos gastrintestinais de caprinos criados em sistema de base agroecológica: resultados preliminares.
O objetivo desse trabalho foi avaliar a eficácia das sementes do nim (Azadiracht indica A. Juss) no controle das verminoses gastrintestinais de caprinos criados no sistema de produção do Cabrito Ecológico da Embrapa Semi-Árido. O trabalho foi realizado durante a época chuvosa (fevereiro a março), utilizando 18 caprinos ser padrão racial definido, divididos em três grupos homogêneos de acordo com os seguintes tratamentos: T1 controle (água); T2 (1,0 glkg) e T3 (3,0 glkg). Foram realizadas três aplicações com intervalo de 13 dias. Para avaliar a eficácia dos tratamentos, foi realizada a contagem do número de ovos de nematódeos pc gramas de fezes (OPG) antes e sete dias após as dosificações. Foi observado aumento do OPG em quase todos os tratamentos. Nas condições desse trabalho, a sementes do nim não foram eficazes no controle de nematódeos gastrintestinais de caprinos
Avaliação de plantas medicinais no controle de nematódeos gastrintestinais de caprinos criados em sistema de base agroecológica.
Este trabalho objetivou avaliar a eficácia de plantas medicinais no controle de nematódeos gastrintestinais. Foram utilizados 36 caprinos distribuídos em seis grupos de seis animais, nos seguintes tratamentos: T1 água (50 mL/animal); T2 closantel (10 mg/kg); T3 Curcubita sp. (3 g/kg); T4 Operculina sp. (8 g/kg); T5 Azadirachta indica (1 g/kg) e T6 Azadirachta indica (3 g/kg). As dosagens foram administradas após 12 horas de jejum, sob a forma de suco, por via oral. A eficácia dos tratamentos foi obtida pela contagem do OPG antes e sete dias após os tratamentos. A média do número de OPG antes dos tratamentos em todas as avaliações foi de 2.500 ovos. Apesar da discreta redução do OPG causada pelo T3 (41,0%) e T4 (34,9%) após a primeira administração, o OPG ainda permaneceu bastante elevado. Nos tratamentos T1, T5 e T6 foi observado aumento do OPG. A eficiência do closantel (T2) foi de 75,9%. Portanto, as dosagens utilizadas não apresentaram eficácia na redução do OPG
On the Integrability and Chaos of an N=2 Maxwell-Chern-Simons-Higgs Mechanical Model
We apply different integrability analysis procedures to a reduced (spatially
homogeneous) mechanical system derived from an off-shell non-minimally coupled
N=2 Maxwell-Chern-Simons-Higgs model that presents BPS topological vortex
excitations, numerically obtained with an ansatz adopted in a special -
critical coupling - parametric regime. As a counterpart of the regularity
associated to the static soliton-like solution, we investigate the possibility
of chaotic dynamics in the evolution of the spatially homogeneous reduced
system, descendant from the full N=2 model under consideration. The originally
rich content of symmetries and interactions, N=2 susy and non-minimal coupling,
singles out the proposed model as an interesting framework for the
investigation of the role played by (super-)symmetries and parametric domains
in the triggering/control of chaotic behavior in gauge systems.
After writing down effective Lagrangian and Hamiltonian functions, and
establishing the corresponding canonical Hamilton equations, we apply global
integrability Noether point symmetries and Painleveproperty criteria to both
the general and the critical coupling regimes. As a non-integrable character is
detected by the pair of analytical criteria applied, we perform suitable
numerical simulations, as we seek for chaotic patterns in the system evolution.
Finally, we present some Comments on the results and perspectives for further
investigations and forthcoming communications.Comment: 18 pages, 5 figure
Propagação de figueira (Ficus carica L.) por meio de estacas retiradas durante o período vegetativo.
Na obtenção de mudas de figueira (Ficus carica L.) de raiz nua por meio de estacas lenhosas, além de demandar em torno de um ano para sua obtenção, ocorre alto percentual de perda, requerendo grande quantidade de material vegetal. Com o uso de estacas herbáceas, objetivou-se verificar o seu enraizamento influenciado pela presença e ausência das folhas, coletadas de plantas-matrizes com e sem frutos e tratadas com AIB em diferentes concentrações. As estacas herbáceas foram retiradas da porção mediana de ramos de figueira Roxo de Valinhos preparadas com 25 cm de comprimento e 15 mm de diâmetro aproximadamente e foram imersas em solução de AIB nas concentrações de 0,150 e 300 mg L-1 durante 24 horas. Posteriormente, foram plantadas em sacolas de polietileno preto contendo areia lavada e solo em mistura na proporção de 3:2 v/v como substrato e mantidas em casa-de-vegetação sob nebulização intermitente durante 60 dias. Maiores percentuais de enraizamento, peso da matéria seca das brotações e das raízes foram obtidas em estacas sem folhas e coletadas de plantas-matrizes sem frutos. Constatou-se ainda que não houve necessidade do tratamento das estacas com AIB.Comunicação
Potentialities of two solventless extraction approaches—Stir bar sorptive extraction and headspace solid-phase microextraction for determination of higher alcohol acetates, isoamyl esters and ethyl esters in wines
A stir bar sorptive extraction with liquid desorption followed by large volume injection coupled to gas chromatography–quadrupole mass spectrometry (SBSE-LD/LVI-GC–qMS) was evaluated for the simultaneous determination of higher alcohol acetates (HAA), isoamyl esters (IsoE) and ethyl esters (EE) of fatty acids. The method performance was assessed and compared with other solventless technique, the solid-phase microextraction (SPME) in headspace mode (HS). For both techniques, influential experimental parameters were optimised to provide sensitive and robust methods. The SBSE-LD/LVI methodology was previously optimised in terms of extraction time, influence of ethanol in the matrix, liquid desorption (LD) conditions and instrumental settings. Higher extraction efficiency was obtained using 60 min of extraction time, 10% ethanol content, n-pentane as desorption solvent, 15 min for the back-extraction period, 10 mL min−1 for the solvent vent flow rate and 10 °C for the inlet temperature. For HS-SPME, the fibre coated with 50/30 μm divinylbenzene/carboxen/polydimethylsiloxane (DVB/CAR/PDMS) afforded highest extraction efficiency, providing the best sensitivity for the target volatiles, particularly when the samples were extracted at 25 °C for 60 min under continuous stirring in the presence of sodium chloride (10% (w/v)). Both methodologies showed good linearity over the concentration range tested, with correlation coefficients higher than 0.984 for HS-SPME and 0.982 for SBES-LD approach, for all analytes. A good reproducibility was attained and low detection limits were achieved using both SBSE-LD (0.03–28.96 μg L−1) and HS-SPME (0.02–20.29 μg L−1) methodologies. The quantification limits for SBSE-LD approach ranging from 0.11 to 96.56 μg L−and from 0.06 to 67.63 μg L−1 for HS-SPME. Using the HS-SPME approach an average recovery of about 70% was obtained whilst by using SBSE-LD obtained average recovery were close to 80%. The analytical and procedural advantages and disadvantages of these two methods have been compared.
Both analytical methods were used to determine the HAA, IsoE and EE fatty acids content in “Terras Madeirenses” table wines. A total of 16 esters were identified and quantified from the wine extracts by HS-SPME whereas by SBSE-LD technique were found 25 esters which include 2 higher alcohol acetates, 4 isoamyl esters and 19 ethyl esters of fatty acids. Generally SBSE-LD provided higher sensitivity with decreased analysis time
Situação atual e perspectivas da caprinocultura no Vale do São Francisco.
Caracterização física e agro-sócio-econômico da zona caprinícola do Vale do São Francisco; Limitações da Caprinocultura regional; Potencialidades da Caprinocultura regional; O mercado para os produtos caprinos e ovinos; O potencial de interação com as áreas irrigadas e com outras atividades agrrícolas e não agrícolas; Infraestrutura agroindustrial; O expressivo dispositivo institucional da região; Proposta de um programa de desenvolvimento
Resolved Young Binary Systems And Their Disks
We have conducted a survey of young single and multiple systems in the Taurus–Auriga star-forming region with the Atacama Large Millimeter Array (ALMA), substantially improving both the spatial resolution and sensitivity with which individual protoplanetary disks in these systems have been observed. These ALMA observations can resolve binary separations as small as 25–30 au and have an average 3σ detection level of 0.35 mJy, equivalent to a disk mass of 4 × 10−5 M ⊙ for an M3 star. Our sample was constructed from stars that have an infrared excess and/or signs of accretion and have been classified as Class II. For the binary and higher-order multiple systems observed, we detect λ = 1.3 mm continuum emission from one or more stars in all of our target systems. Combined with previous surveys of Taurus, our 21 new detections increase the fraction of millimeter-detected disks to over 75% in all categories of stars (singles, primaries, and companions) earlier than spectral type M6 in the Class II sample. Given the wealth of other information available for these stars, this has allowed us to study the impact of multiplicity with a much larger sample. While millimeter flux and disk mass are related to stellar mass as seen in previous studies, we find that both primary and secondary stars in binary systems with separations of 30–4200 au have lower values of millimeter flux as a function of stellar mass than single stars. We also find that for these systems, the circumstellar disk around the primary star does not dominate the total disk mass in the system and contains on average 62% of the total mass
Criticality in the 2+1-dimensional compact Higgs model and fractionalized insulators
We use a novel method of computing the third moment M_3 of the action of the
2+1-dimensional compact Higgs model in the adjoint representation with q=2 to
extract correlation length and specific heat exponents nu and alpha, without
invoking hyperscaling. Finite-size scaling analysis of M_3 yields the ratio
(1+alpha)/nu and 1/nu separately. We find that alpha and nu vary along the
critical line of the theory, which however exhibits a remarkable resilience of
Z_2 criticality. We propose this novel universality class to be that of the
quantum phase transition from a Mott-Hubbard insulator to a
charge-fractionalized insulator in two spatial dimensions.Comment: 4 pages, 3 figures, submitted to Phys. Rev. Let
The superconducting phase transition and gauge dependence
The gauge dependence of the renormalization group functions of the
Ginzburg-Landau model is investigated. The analysis is done by means of the
Ward-Takahashi identities. After defining the local superconducting order
parameter, it is shown that its exponent is in fact gauge independent.
This happens because in the Landau gauge is the only gauge having a
physical meaning, a property not shared by the four-dimensional model where any
gauge choice is possible. The analysis is done in both the context of the
-expansion and in the fixed dimension approach. It is pointed out the
differences that arise in both of these approaches concerning the gauge
dependence.Comment: RevTex, 3 pages, no figures; accepted for publication in PRB; this
paper is a short version of cond-mat/990527
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