626 research outputs found
Development of molecular biology techniques for the detection of genetically modified organisms in maize food products
In the last years, the increase in the cultivated area of genetically modified (GM) maize has become a reality. GA21, MON810 and MON 863 maize crops are some of the authorized maize events for food and feed under the European Union (EU) regulations. These crops of transgenic maize bring profit towards the conventional ones, as they confer resistence to some plagues and/or herbices. Concerning the raise of production and consumption of foodstuffs derived from genetically modified organisms (GMO), the EU has established new demand levels, including the labeling requirements when the product has GMO in proportion higher than 0.9% (Regulation (EC) NÂș. 1829/2003)
Detection of Borrelia lusitaniae, Rickettsia sp. IRS3, Rickettsia monacensis and Anaplasma phagocytophilum in Ixodes ricinus collected in Madeira Island, Portugal
A total of 300 Ixodes ricinus ticks were tested by polymerase chain reaction (PCR) for the presence of Borrelia spp., Rickettsia spp., and Anaplasma phagocytophilum. Sequence analysis demonstrated 8 (2.7%) ticks infected with B. lusitaniae, 60 (20%) with Rickettsia spp., and 1 (0.3%) with A. phagocytophilum. Seven (2.3%) ticks were coinfected with B. lusitaniae and Rickettsia spp., 2 (0.6%) with R. monacensis, and 5 (1.7%) with Rickettsia sp. IRS3. The results of this study suggest simultaneous transmission of multiple tick-borne agents on Madeira Island, Portugal
Measurement of cognitive bias and cortisol levels to evaluate the effects of space restriction on captive collared peccary (Mammalia, Tayassuidae)
We use the judgement-bias paradigm to evaluate whether space restriction in metabolism pens affects the emotional state of collared peccary (Pecari tajacu) during a nutritional experiment. We trained individual adult males to âgoâ to a specific location within 30 s when a positive auditory cue (whistle; CS+) was given in order to receive cassava root pieces as a reward, and to âno-goâ when a negative cue (caxixi percussion instrument; CSâ) was sounded to avoid punishment (jet of water) and no reward. An âambiguousâ auditory cue (a drumstick hitting an aluminum plate; CSA) was presented to probe decision-making under ambiguity. Individuals were subjected to five 8-day housing conditions in the order: H1 (control-no space restriction-metabolism pen and additional area), H2 space restriction without environmental enrichment (metabolism pen only), H3 (control-no space restriction), H4 (space restriction with environmental enrichment), and H5 (control-no space restriction). On the eighth day of each housing condition, each animal was exposed to 10 judgement bias trials of each of the three cue types: CS+, CSâ, and CSA. We recorded whether animals showed the âgoâ or âno-goâ response after each type of cue and collected fecal samples to assess fecal glucocorticoid metabolite concentrations. Peccaries learnt to discriminate CS+ and CSâ and maintained this discrimination during the five housing conditions tested. The response to the ambiguous cue (CSA) varied according to the housing condition. During H1, the peccaries made a similar proportion of âgoâ responses to all three types of cue (Ps > 0.07). During H2 and H3, âgoâ responses to CSA and CSâ cues occurred in similar proportions (Ps > 0.70), but peccaries showed more go responses to CS+ (Ps < 0.03) indicating that they were responding to CSA as if it were more likely to predict the waterjet than food. During H4 and H5, peccaries again made a similar proportion of âgoâ responses to all three types of cue, as in H1. During H2 and H3, fecal glucocorticoid metabolite concentrations were higher than during the other tests (208.0 ± 16.4 vs. 141.6 ± 25.9 nggâ1 dry feces, Ps < 0.03). Our results suggest that space restriction may induce physiological stress and influence judgement bias and affective state in peccaries, and that these effects may be offset by environmental enrichment. However, the possibility of a general habituation to the housing conditions across time cannot be ruled out
Characterization of tillers in deferred Piata palisade grass with different initial heights and nitrogen levels
IncidĂȘncia do mĂldio em cebola sob adubação mineral e orgĂąnica.
Analisou-se a relação entre adubação mineral e orgĂąnica sobre a incidĂȘncia de mĂldio (Peronospora destructor) em cebola (Allium cepa). O trabalho constituiu-se de dois experimentos localizados em Ituporanga, conduzidos entre agosto e dezembro de 1998. O experimento 1, com fontes orgĂąnicas, constou dos tratamentos: esterco de suĂnos, esterco de aves, composto, esterco de peru e hĂșmus, na dosagem de 75 kg/ha de N; esterco de suĂnos, na dosagem de 37,5 kg/ha de N; adubação mineral, 30-120-60 kg/ha de N-P2O5-K2O; 60-240-120 kg/ha de N-P2O5-K2O e testemunha sem adubação. O experimento 2 constou dos tratamentos: fontes minerais, 30-120-60 kg/ha de N-P2O5-K2O; 90-360-180 kg/ha de N-P2O5-K2O; 75 kg/ha de N; 225 kg/ha de N; 80 kg/ha de P2O5; 240 kg/ha de P2O5; 60 kg/ha de K2O; 180 kg/ha de K2O; esterco de suĂnos + fosfato natural, em trĂȘs combinaçÔes, 7,9+0,1, 15,7+0,2 e 47,2+0,6 t/ha, respectivamente;
testemunha sem adubação. NĂŁo houve diferença entre as fontes mineral e orgĂąnica sobre a incidĂȘncia de mĂldio. A relação entre nutrientes e doença foi variĂĄvel entre datas de amostragem e distinta para fontes minerais e orgĂąnicas
Morphogenetic and structural characteristics of tillers of guinea grass of different age and grazing severities
Effects of Epitope Modification on T Cell ReceptorâLigand Binding and Antigen Recognition by Seven H-2Kdârestricted Cytotoxic T Lymphocyte Clones Specific for a Photoreactive Peptide Derivative
We tested for antigen recognition and T cell receptor (TCR)âligand binding 12 peptide derivative variants on seven H-2Kdârestricted cytotoxic T lymphocytes (CTL) clones specific for a bifunctional photoreactive derivative of the Plasmodium berghei circumsporozoite peptide 252â 260 (SYIPSAEKI). The derivative contained iodo-4-azidosalicylic acid in place of PbCS S-252 and 4-azidobenzoic acid on PbCS K-259. Selective photoactivation of the N-terminal photoreactive group allowed crosslinking to Kd molecules and photoactivation of the orthogonal group to TCR. TCR photoaffinity labeling with covalent Kdâpeptide derivative complexes allowed direct assessment of TCRâligand binding on living CTL. In most cases (over 80%) cytotoxicity (chromium release) and TCRâligand binding differed by less than fivefold. The exceptions included (a) partial TCR agonists (8 cases), for which antigen recognition was fivetenfold less efficient than TCRâligand binding, (b) TCR antagonists (2 cases), which were not recognized and capable of inhibiting recognition of the wild-type conjugate, (c) heteroclitic agonists (2 cases), for which antigen recognition was more efficient than TCRâligand binding, and (d) one partial TCR agonist, which activated only Fas (CD95), but not perforin/granzymemediated cytotoxicity. There was no correlation between these divergences and the avidity of TCRâligand binding, indicating that other factors than binding avidity determine the nature of the CTL response. An unexpected and novel finding was that CD8-dependent clones clearly incline more to TCR antagonism than CD8-independent ones. As there was no correlation between CD8 dependence and the avidity of TCRâligand binding, the possibility is suggested that CD8 plays a critical role in aberrant CTL function
Electro-osmotic flow of couple stress fluids in a microchannel propagated by peristalsis
A mathematical model is developed for electro-osmotic peristaltic pumping of a non-Newtonian liquid in a deformable micro-channel. Stokesâ couple stress fluid model is deployed to represent realistic working liquids. The Poisson-Boltzmann equation for electric potential distribution is implemented owing to the presence of an electrical double layer (EDL) in the micro-channel. Using long wavelength, lubrication theory and Debye-Huckel approximations, the linearized transformed dimensionless boundary value problem is solved analytically. The influence of electro-osmotic parameter (inversely proportional to Debye length), maximum electro-osmotic velocity (a function of external applied electrical field) and couple stress parameter on axial velocity, volumetric flow rate, pressure gradient, local wall shear stress and stream function distributions is evaluated in detail with the aid of graphs. The Newtonian fluid case is retrieved as a special case with vanishing couple stress effects. With increasing couple stress parameter there is a significant elevation in axial pressure gradient whereas the core axial velocity is reduced. An increase in electro-osmotic parameter induces both flow acceleration in the core region (around the channel centreline) and also enhances axial pressure gradient substantially. The study is relevant to simulation of novel smart bio-inspired space pumps, chromatography and medical microscale devices
Search for direct production of charginos and neutralinos in events with three leptons and missing transverse momentum in âs = 7 TeV pp collisions with the ATLAS detector
A search for the direct production of charginos and neutralinos in final states with three electrons or muons and missing transverse momentum is presented. The analysis is based on 4.7 fbâ1 of protonâproton collision data delivered by the Large Hadron Collider and recorded with the ATLAS detector. Observations are consistent with Standard Model expectations in three signal regions that are either depleted or enriched in Z-boson decays. Upper limits at 95% confidence level are set in R-parity conserving phenomenological minimal supersymmetric models and in simplified models, significantly extending previous results
Jet size dependence of single jet suppression in lead-lead collisions at sqrt(s(NN)) = 2.76 TeV with the ATLAS detector at the LHC
Measurements of inclusive jet suppression in heavy ion collisions at the LHC
provide direct sensitivity to the physics of jet quenching. In a sample of
lead-lead collisions at sqrt(s) = 2.76 TeV corresponding to an integrated
luminosity of approximately 7 inverse microbarns, ATLAS has measured jets with
a calorimeter over the pseudorapidity interval |eta| < 2.1 and over the
transverse momentum range 38 < pT < 210 GeV. Jets were reconstructed using the
anti-kt algorithm with values for the distance parameter that determines the
nominal jet radius of R = 0.2, 0.3, 0.4 and 0.5. The centrality dependence of
the jet yield is characterized by the jet "central-to-peripheral ratio," Rcp.
Jet production is found to be suppressed by approximately a factor of two in
the 10% most central collisions relative to peripheral collisions. Rcp varies
smoothly with centrality as characterized by the number of participating
nucleons. The observed suppression is only weakly dependent on jet radius and
transverse momentum. These results provide the first direct measurement of
inclusive jet suppression in heavy ion collisions and complement previous
measurements of dijet transverse energy imbalance at the LHC.Comment: 15 pages plus author list (30 pages total), 8 figures, 2 tables,
submitted to Physics Letters B. All figures including auxiliary figures are
available at
http://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/PAPERS/HION-2011-02
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