Estimating Parasitism of Colorado Potato Beetle Eggs, \u3ci\u3eLeptinotarsa Decemlineata\u3c/i\u3e (Coleoptera: Chrysomelidae), by \u3ci\u3eEdovum Puttleri\u3c/i\u3e (Hymenoptera: Eulophidae)

A computer simulation was used to evaluate methods for estimating parasitism of Colorado potato beetle egg mass populations by Edovum puttleri. The algorithm incorporated the specific attack behavior of E. puttleri, and a development time for parasitized egg masses of ca. 2.9 times that of healthy egg masses. Of the methods compared, a modification of Southwood\u27s graphical technique was found to be most accurate in relation to the true parasitism derived from the algorithm. A regression equation is presented to correct the error in this method at high levels of parasitism. A second simulation was used to test the accuracy of this correcter where in a jacknife procedure was used to generate a mean and variance for estimates of parasitism

The Mira-based distance to the Galactic centre

Mira variables are useful distance indicators, due to their high luminosities and well-defined period-luminosity relation. We select 1863 Miras from SAAO and MACHO observations to examine their use as distance estimators in the Milky Way. We measure a distance to the Galactic centre of $R_0 = 7.9 \pm 0.3$ kpc, which is in good agreement with other literature values. The uncertainty has two components of $\sim$0.2 kpc each: the first is from our analysis and predominantly due to interstellar extinction, the second is due to zero-point uncertainties extrinsic to our investigation, such as the distance to the Large Magellanic Cloud (LMC). In an attempt to improve existing period-luminosity calibrations, we use theoretical models of Miras to determine the dependence of the period-luminosity relation on age, metallicity, and helium abundance, under the assumption that Miras trace the bulk stellar population. We find that at a fixed period of $\log P = 2.4$, changes in the predicted $K_s$ magnitudes can be approximated by $\Delta M_{Ks} \approx -0.109(\Delta \rm{[Fe/H]}) + 0.033( {\Delta}t/\rm{Gyr}) + 0.021 ({\Delta}Y/0.01)$, and these coefficients are nearly independent of period. The expected overestimate in the Galactic centre distance from using an LMC-calibrated relation is $\sim$0.3 kpc. This prediction is not validated by our analysis; a few possible reasons are discussed. We separately show that while the predicted color-color diagrams of solar-neighbourhood Miras work well in the near-infrared, though there are offsets from the model predictions in the optical and mid-infrared.Comment: Accepted for publication in The Astrophysical Journal. 16 pages, 8 figures, 6 table

Testing Asteroseismic Radii of Dwarfs and Subgiants with Kepler and Gaia

We test asteroseismic radii of Kepler main-sequence and subgiant stars by deriving their parallaxes which are compared with those of the first Gaia data release. We compute radii based on the asteroseismic scaling relations as well as by fitting observed oscillation frequencies to stellar models for a subset of the sample, and test the impact of using effective temperatures from either spectroscopy or the infrared flux method. An offset of 3%, showing no dependency on any stellar parameters, is found between seismic parallaxes derived from frequency modelling and those from Gaia. For parallaxes based on radii from the scaling relations, a smaller offset is found on average; however, the offset becomes temperature dependent which we interpret as problems with the scaling relations at high stellar temperatures. Using the hotter infrared flux method temperature scale, there is no indication that radii from the scaling relations are inaccurate by more than about 5%. Taking the radii and masses from the modelling of individual frequencies as reference values, we seek to correct the scaling relations for the observed temperature trend. This analysis indicates that the scaling relations systematically overestimate radii and masses at high temperatures, and that they are accurate to within 5% in radius and 13% in mass for main-sequence stars with temperatures below 6400 K. However, further analysis is required to test the validity of the corrections on a star-by-star basis and for more evolved stars.Comment: 12 pages, 9 figures. Accepted for publication in MNRA

Forage Legumes in Tropical Regions: Recent Advances and Future Challenges

Nitrogen input in tropical pastures increases forage and animal productivity. Forage legumes can fix atmospheric nitrogen and are the most economical way to add this nutrient to the soil. Our objective was to report the benefits of forage legumes in tropical pastures and possible strategies to implement different forage legumes. In tropical conditions, such as in Brazil, the use of forage legumes is still scarce. Even with low legume adoption on tropical pastures, forage legumes can provide ecosystem services. Increased animal productivity is the first ecosystem service provided by these legumes, mainly due to the addition of nitrogen that is typically the most limiting nutrient on tropical soils and yet the most important driver of plant growth and development. Legumes also provide an opportunity to increase nitrogen cycling in grassland, reducing grassland degradation. Pastures that include legumes have greater litter quality than grass monocultures, increasing soil organic matter at a faster rate. Legumes improve diet nutritive value and animal performance, resulting in reduced enteric methane emissions per unit of animal product. Additionally, legumes are generally associated with lower nitrous oxide emissions than N-fertilized grass swards and reduce the carbon footprint from the system due to nitrogen manufacture, transport, storage, and application. However, the greatest challenge in tropical pastures is to increase the adoption of forage legumes. It is necessary to understand the role of different legumes in the pasture environment. Some legumes have high herbage accumulation and biological nitrogen fixation potential, but they have low canopy stability; nonetheless, they could be used on short-lived pastures as well as integrated crop-livestock systems. When the objective is to achieve grass-legume stability in mixed pastures, it is necessary to use clonal propagation legumes and provide appropriate defoliation management to minimize light competition among plant communities

An interleukin-33/ST2 signaling deficiency reduces overt pain-like behaviors in mice

Interleukin (IL)-33, the most recent member of the IL family of cytokines, signals through the ST2 receptor. IL-33/ST2 signaling mediates antigen challenge-induced mechanical hyperalgesia in the joints and cutaneous tissues of immunized mice. The present study asked whether IL-33/ST2 signaling is relevant to overt pain-like behaviors in mice. Acetic acid and phenyl-p-benzoquinone induced significant writhing responses in wild-type (WT) mice; this overt nociceptive behavior was reduced in ST2-deficient mice. In an antigen-challenge model, ST2-deficient immunized mice had reduced induced flinch and licking overt pain-like behaviors. In the formalin test, ST2-deficient mice also presented reduced flinch and licking responses, compared with WT mice. Naive WT and ST2-deficient mice presented similar responses in the rota-rod, hot plate, and electronic von Frey tests, indicating no impairment of motor function or alteration in basal nociceptive responses. The results demonstrate that IL-33/ST2 signaling is important in the development of overt pain-like behaviors

Percepção de agricultores do entorno do parque estadual Fritz Plaumann sobre o código florestal.

Projeto/Plano de Ação: 06.09.06.001

Three-dimensional hydrodynamical simulations of red giant stars: semi-global models for the interpretation of interferometric observations

Context. Theoretical predictions from models of red giant branch stars are a valuable tool for various applications in astrophysics ranging from galactic chemical evolution to studies of exoplanetary systems. Aims. We use the radiative transfer code OPTIM3D and realistic 3D radiative-hydrodynamical (RHD) surface convection simulations of red giants to explore the impact of granulation on interferometric observables. Methods. We compute intensity maps for the 3D simulation snapshots in two filters: in the optical at 5000 \pm 300 {\AA} and in the K band 2.14 $\pm$ 0.26 {\mu}m FLUOR filter, corresponding to the wavelength-range of instruments mounted on the CHARA interferometer. From the intensity maps, we construct images of the stellar disks, accounting for center-to-limb variations. We then derive interferometric visibility amplitudes and phases. We study their behavior with position angle and wavelength. Results. We provide average limb-darkening coefficients for different metallicities and wavelength-ranges. We detail the prospects for the detection and characterization of granulation and center-to-limb variations of red giant stars with today's interferometers. We find that the effect of convective-related surface structures depends on metallicity and surface gravity. We provided theoretical closure phases that should be incorporated into the analysis of red giant planet companion closure phase signals. We estimate 3D-1D corrections to stellar radii determination: 3D models are ~ 3.5% smaller to ~ 1% larger in the optical with respect to 1D, and roughly 0.5 to 1.5% smaller in the infrared. Even if these corrections are small, they are important to properly set the zero point of effective temperature scale derived by interferometry and to strengthen the confidence of existing red giant catalogues of calibrating stars for interferometry.Comment: Accepted for publication on Astronomy & Astrophysics, 14 pages, 13 figure

unveiling systematic biases in the 1d lte excitation-ionization balance of fe for fgk stars: A novel approach to determination of stellar parameters

We present a comprehensive analysis of different techniques available for the spectroscopic analysis of FGK stars and provide a recommended methodology which efficiently estimates accurate stellar atmospheric parameters for large samples of stars. Our analysis includes a simultaneous equivalent width analysis of Fe I and Fe II spectral lines, and for the first time, utilizes on-the-fly non-local thermodynamic equilibrium (NLTE) corrections of individual Fe I lines. We further investigate several temperature scales, finding that estimates from Balmer line measurements provide the most accurate effective temperatures at all metallicities. We apply our analysis to a large sample of both dwarf and giant stars selected from the Radial Velocity Experiment (RAVE) survey. We then show that the difference between parameters determined by our method and that by the standard 1D LTE excitation-ionization balance of Fe reveals substantial systematic biases: up to 400 K in effective temperature, 1.0 dex in surface gravity and 0.4 dex in metallicity for stars with [Fe/H] -2.5. This has large implications for the study of the stellar populations in the Milky Wa

High entropy alloys obtained by field assisted powder metallurgy route: SPS and microwave heating

The aim of this work was to investigate the field assisted powder metallurgy route for producing HEAs at equimolar composition, i.e. FeCoNiCrAl, starting from metal powders. Both mixed, mechanically activated and mechanically alloyed powders have been used. The powders obtained by mechanical alloying were synthesized only by SPS, whereas the remaining ones were sintered by SPS or microwave heating. The investigated field assisted sintering techniques allowed an extremely short alloying time, high energy density on the load and negligible contamination by the surrounding environment. Both the conducted sintering-synthesis technology resulted not definitive to produce chemical homogeneity and to obtain a single stable structure. Thus a subsequently heat treatment was required. The post heat treatment, indeed, led to a single crystalline structure (FCC) and the material was fully recrystallized. After heat treatment samples are isomorphic: they exhibit two different phases with the same FCC cell, but different chemical composition, in detail Fe-Cr richer and Al-Ni richer. SPS-ed samples present a reduced porosity, while microwave processed ones are much more porous and this is reflected in the mechanical properties