3,313 research outputs found
Does functional soil microbial diversity contribute to explain within-site plant beta-diversity in an alpine grassland and a <i>dehesa</i> meadow in Spain?
Questions: Once that the effects of hydrological and chemical soil properties have been accounted for, does soil microbial diversity contribute to explain change in plant community structure (i.e. within-site beta-diversity)? If so, at which spatial scale does microbial diversity operate?
Location: La Mina in Moscosa Farm, Salamanca, western Spain (dehesa community) and Laguna Larga in the Urbión Peaks, Soria, central-northern Spain (alpine grassland).
Methods: The abundance of vascular plant species, soil gram-negative microbial functional types and soil chemical properties (pH, available phosphorus, and extractable cations) were sampled at both sites, for which hydrological models were available. Redundancy analysis (RDA) was used to partition variation in plant community structure into hydrological, chemical and microbial components. Spatial filters, arranged in scalograms, were used to test for the spatial scales at which plant community structure change.
Results: In the case of the dehesa the diversity of soil gram-negative microbes, weakly driven by soil pH, contributed to a small extent (adj-R2 = 2%) and at a relative medium spatial scale to explain change in plant community structure. The abundance of a few dehesa species, both annual (Trifolium dubium, Vulpia bromoides) and perennial (Poa bulbosa, Festuca ampla), was associated with either increasing or decreasing soil microbial diversity. In the alpine meadow the contribution was negligible.
Conclusions: Microbial diversity can drive community structure, though in the hierarchy of environmental factors structuring communities it appears to rank lower than other soil factors. Still, microbial diversity appears to promote or restrain individual plant species. This paper aims to encourage future studies to use more comprehensive and insightful techniques to assess microbial diversity and to combine this with statistical approaches such as the one used here
Carbon and oxygen in HII regions of the Magellanic Clouds: abundance discrepancy and chemical evolution
We present C and O abundances in the Magellanic Clouds derived from deep
spectra of HII regions. The data have been taken with the Ultraviolet-Visual
Echelle Spectrograph at the 8.2-m VLT. The sample comprises 5 HII regions in
the Large Magellanic Cloud (LMC) and 4 in the Small Magellanic Cloud (SMC). We
measure pure recombination lines (RLs) of CII and OII in all the objects,
permitting to derive the abundance discrepancy factors (ADFs) for O^2+, as well
as their O/H, C/H and C/O ratios. We compare the ADFs with those of other HII
regions in different galaxies. The results suggest a possible metallicity
dependence of the ADF for the low-metallicity objects, but more uncertain for
high-metallicity objects. We compare nebular and B-type stellar abundances and
we find that the stellar abundances agree better with the nebular ones derived
from collisionally excited lines (CELs). Comparing these results with other
galaxies we observe that stellar abundances seem to agree better with the
nebular ones derived from CELs in low-metallicity environments and from RLs in
high-metallicity environments. The C/H, O/H and C/O ratios show almost flat
radial gradients, in contrast with the spiral galaxies where such gradients are
negative. We explore the chemical evolution analysing C/O vs. O/H and comparing
with the results of HII regions in other galaxies. The LMC seems to show a
similar chemical evolution to the external zones of small spiral galaxies and
the SMC behaves as a typical star-forming dwarf galaxy.Comment: Accepted for publication in MNRAS, 17 pages, 11 figures, 8 table
Agrio et Emulsio – development of fruity mustard creams
Agrio et Emulsio project (POCI-01-0145-FEDER-023583) presents an proposal in the areas
of vinegar products and food emulsions. Combining technical features with mediterranean
traditions and Nouvelle Cuisine, two prototypes of fruity mustards are undergoing final
development, valuing regional raw materials and profiling into the gourmet/vegan/veggie
markets. Mustard creams are oil-in-water emulsions but its practice is linked to vinegar
traditions since the thirteenth century, in France, with the foundation of the first confraternity
of Maîtres Vinaigrier-Moutardier. Thus, by applying the ancestral practice, mustard (seeds,
fragments, powder) was first submitted to maturation studies, varying the type of vinegar and
the time of immersion/contact. Maturation reached equilibrium on the 16th day, but pH
evolution shows a practically stationary state from the 7th. Best results were obtained with
seeds and powdered mustards in red wine vinegar, 4 %(m/v) acidity. The assays were carried
out at room temperature using Sinapis Alba (Linnaeus) mustard species. Prototyping
articulated technical, analytical (physicochemical, rheological, microbiological) and sensory
tests. Each final prototype has a distinct profile of ingredients, mustard, fruits (raspberry and
beet or blueberry), olive oil, water, salt, sugar, honey and spices. Both creams retain the sui
generis taste of mustard tinted with the fruit flavour plus an innovative pink colour.info:eu-repo/semantics/publishedVersio
Probing Non-Standard Neutrino Interactions with Neutrino Factories
We discuss the sensitivity reach of a neutrino factory measurement to
non-standard neutrino interactions (NSI), which may exist as a low-energy
manifestation of physics beyond the Standard Model. We use the muon appearance
mode \nu_e --> \nu_\mu and consider two detectors, one at 3000 km and the other
at 7000 km.
Assuming the effects of NSI at the production and the detection are
negligible, we discuss the sensitivities to NSI and the simultaneous
determination of \theta_{13} and \delta by examining the effects in the
neutrino propagation of various systems in which two NSI parameters
\epsilon_{\alpha \beta} are switched on. The sensitivities to off-diagonal
\epsilon's are found to be excellent up to small values of \theta_{13}.
We demonstrate that the two-detector setting is powerful enough to resolve
the \theta_{13}-NSI confusion problem. We believe that the results obtained in
this paper open the door to the possibility of using neutrino factory as a
discovery machine for NSI while keeping its primary function of performing
precision measurements of the lepton mixing parameters.Comment: 47 pages, 22 figures. Color version of Figs. 18, 19 and 22 can be
found in the article published in JHE
Fokker-Planck type equations with Sobolev diffusion coefficients and BV drift coefficients
In this paper we give an affirmative answer to an open question mentioned in
[Le Bris and Lions, Comm. Partial Differential Equations 33 (2008),
1272--1317], that is, we prove the well-posedness of the Fokker-Planck type
equations with Sobolev diffusion coefficients and BV drift coefficients.Comment: 11 pages. The proof has been modifie
Probing Nonstandard Neutrino Physics by Two Identical Detectors with Different Baselines
The Kamioka-Korea two detector system is a powerful experimental setup for
resolving neutrino parameter degeneracies and probing CP violation in neutrino
oscillation. In this paper, we study sensitivities of this same setup to
several nonstandard neutrino physics such as quantum decoherence, tiny
violation of Lorentz symmetry, and nonstandard interactions of neutrinos with
matter. In most cases, the Kamioka-Korea two-detector setup is more sensitive
than the one-detector setup, except for the Lorentz symmetry violation with CPT
violation, and the nonstandard neutrino interactions with matter. It can
achieve significant improvement on the current bounds on nonstandard neutrino
physics.Comment: 20 pages, 6 figure
Fruit quality of Chenin Blanc grape influenced by different rootstocks during a production cycle in the second half.
This study aimed to evaluate the influence of different rootstocks on physico-chemical characteristics of the fruits of Chenin Blanc grapes produced in the second half of the year
Análise sensorial e microbiológica da carne ovina submetida a diferentes formas de conservação no pós-abate.
Foram utilizados seis cordeiros machos da raça Santa Inês, castrados, com idade média de quatro meses, que foram abatidos com peso entre 30-35 kg com o objetivo de avaliar o e feito de três tipos de acondicionamento da carne ovina (natural, resfriada e congelada) na qualidade sensorial e microbiológica da carne. Para a análise sensorial foi separado e preparado o músculo Longissimus dorsi para um painel de provadores que avaliaram a carne quanto ao aroma, sabor, maciez, suculência, mastigabilidade e aparência geral. O mesmo músculo foi utilizado para a análise microbiológica onde se determinaram coliformes totais e fecais, bolores e leveduras. A carne in natura foi mais macia e de melhor mastigabilidade (p<0,05) em relação à resfriada e congelada. Observou-se também nas carcaças não resfriadas maior incidência de bolores e leveduras e presença de coliformes fecais. Apesar da carne in natura ter apresentado maior maciez, o crescimento microbiano foi maior neste tipo de conservação pós abate, o que pode comprometer a saúde humana
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