419 research outputs found
Challenging Classification Bias with Linked Data
Can library classification systems find new ways to deal with charges of bias? Can linked data contribute a more inclusive representation of diverse voices and communities? This panel will discuss the inherent biases present in cataloguing and classification, and consider the potential for linked data to provide a space to highlight and explore the challenging political issues that can arise in our work. These include issues related to jurisdiction, territory, and community with examples drawn from legal classification and the classification of cartographic resources
Screening Ryegrass Cultivars for Aluminium Sensitivity in Nutrient Soluations
The objective of this study was to evaluate Al and H+ tolerance of nine ryegrass (Lolium perenne and L. multiflorum) cultivars by growing plants in a mineral solution (pH 4.8 and 6.0 and 0-200 (M Al). Results showed that Yatsyn-1, with a relative root length of 91 was the cultivar least affected by acidity (H+), and Concord ( RRLpH = 58) was the cultivar with the highest H+ sensitivity. In connection with Al-tolerance, Yatsyn-1 and Concord, were the most tolerant cultivars with 88 and 87 RRLAl, respectively whereas Nui and Marathon, were the most sensitive ones, reaching only a 66, 60 RRLAl, respectively
Hyperfine Structure of S-States in Muonic Helium Ion
Corrections of orders alpha^5 and alpha^6 are calculated in the hyperfine
splittings of 1S and 2S - energy levels in the ion of muonic helium. The
electron vacuum polarization effects, the nuclear structure corrections and
recoil corrections are taken into account. The obtained numerical values of the
hyperfine splittings -1334.56 meV (1S state), -166.62 meV (2S state) can be
considered as a reliable estimate for the comparison with the future
experimental data. The hyperfine splitting interval Delta_{12}=(8 Delta
E^{hfs}(2S)- Delta E^{hfs}(1S)) = 1.64 meV can be used for the check of quantum
electrodynamics.Comment: 14 pages, 5 figure
Improved radiative corrections for (e,e'p) experiments: Beyond the peaking approximation and implications of the soft-photon approximation
Analysing (e,e'p) experimental data involves corrections for radiative
effects which change the interaction kinematics and which have to be carefully
considered in order to obtain the desired accuracy. Missing momentum and energy
due to bremsstrahlung have so far always been calculated using the peaking
approximation which assumes that all bremsstrahlung is emitted in the direction
of the radiating particle. In this article we introduce a full angular Monte
Carlo simulation method which overcomes this approximation. The angular
distribution of the bremsstrahlung photons is reconstructed from H(e,e'p) data.
Its width is found to be underestimated by the peaking approximation and
described much better by the approach developed in this work.Comment: 11 pages, 13 figure
Diversity of mycorrhizal plant species and arbuscular mycorrhizal fungi in evergreen forest, deciduous forest and grassland ecosystems of Southern Chile
In the Valdivian rainforest region of the Southern Chilean Andes three main ecosystems are found: Primary evergreen forests, secondary deciduous forests, and grassland areas. The secondary forest and the grasslands are habitually the result of the clearance of the primary forest some 60 years ago. The secondary forest consists mainly of the deciduous tree species Nothofagus alpina; forest management practices such as crown thinning and clearance of the understorey are applied to the secondary forest to improve its economic value. The grasslands are used by extensive cattle grazing. Soils in this region are acid Andosols with high organic matter content, high exchangeable aluminum and low levels of available phosphorus. The main objective of this study was to investigate the diversity of arbuscular mycorrhizal (AM) plant species and of arbuscular mycorrhizal fungi (AMF) in these three ecosystems. The highest diversity with 53 plant species was found in the evergreen forest with 77.4% of them AM, while in the grassland 91% of the 22 plant species were AM. The deciduous forest had 11 plant species only and the lowest proportion of AM plant species (55%). Thirty-nine AM fungal species were found in total, of which most are being reported for the first time from Southern Chile. Thirteen fungal species were of the Acaulospora genus, 10 of Glomus, 4 species each of Scutellospora and Archaeospora, 3 species each of Pacispora and Entrophospora, and one species each of Paraglomus and Diversispora. AMF species were more abundant in the grassland (29 spp.) than in the evergreen forest (20 spp.) which is likely related to a higher relative proportion of AM plant species in the grassland. Four AMF species were present in all the ecosystems, and 15 species were apparently quite specific as they were only found in one of the ecosystems. Noteworthy was the lack of Paraglomus and Scutellospora spp. in any of the forest ecosystems, and the relatively higher presence of Entrophospora spores in those ecosystems. It was concluded that the diversity of the AMF species in the ecosystems is strongly influenced by the proportion of AM plant species in each ecosystem and that their diversity is not related to soil chemical properties
Determining the size of the proton
A measurement of the Lamb shift of 49,881.88(76) GHz in muonic hydrogen in
conjunction with theoretical estimates of the proton structure effects was
recently used to deduce an accurate but rather small radius of the proton. Such
an important shift in the understanding of fundamental values needs
reconfirmation. Using a different approach with electromagnetic form factors of
the proton, we obtain a new expression for the transition energy, , in muonic hydrogen and deduce
a proton radius, fm.Comment: 20 pages LaTe
Efecto de la adición de compost en la agregación de un ultisol bajo un sistema de rotación de cultivos.
Effect of compost application on some properties of a volcanic soil from central south Chile.
Temperature dependence of the diffuse scattering fine structure in equiatomic CuAu
The temperature dependence of the diffuse scattering fine structure from
disordered equiatomic CuAu was studied using {\it in situ} x-ray scattering. In
contrast to CuAu the diffuse peak splitting in CuAu was found to be
relatively insensitive to temperature. Consequently, no evidence for a
divergence of the antiphase length-scale at the transition temperature was
found. At all temperatures studied the peak splitting is smaller than the value
corresponding to the CuAuII modulated phase. An extended Ginzburg-Landau
approach is used to explain the temperature dependence of the diffuse peak
profiles in the ordering and modulation directions. The estimated mean-field
instability point is considerably lower than is the case for CuAu.Comment: 4 pages, 5 figure
Ionization Potential of the Helium Atom
Ground state ionization potential of the He^4 atom is evaluated to be 5 945
204 221 (42) MHz. Along with lower order contributions, this result includes
all effects of the relative orders alpha^4, alpha^3*m_e/m_alpha and
alpha^5*ln^2(alpha).Comment: 4 page
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