549 research outputs found
Monte Carlo simulation with time step quantification in terms of Langevin dynamics
For the description of thermally activated dynamics in systems of classical
magnetic moments numerical methods are desirable. We consider a simple model
for isolated magnetic particles in a uniform field with an oblique angle to the
easy axis of the particles. For this model, a comparison of the Monte Carlo
method with Langevin dynamics yields new insight in the interpretation of the
Monte Carlo process, leading to the implementation of a new algorithm where the
Monte Carlo step is time-quantified. The numeric results for the characteristic
time of the magnetisation reversal are in excellent agreement with asymptotic
solutions which itself are in agreement with the exact numerical results
obtained from the Fokker-Planck equation for the Neel-Brown model.Comment: 5 pages, Revtex, 4 Figures include
Evidencias de actividad glaciar durante el Dryas reciente (12, 9-11, 7 ka BP) en la Península Ibérica
El Dryas Reciente (Younger Dryas) (GS-1, entre 12, 9 y 11, 7 ka BP) se caracterizó por un marcado descenso de la temperatura a escala global. La consecuencia fue un re avance de los glaciares que afectó también a las cordilleras más importantes de la Península Ibérica. Este trabajo revisa la información disponible sobre la localización, evolución y extensión de tales glaciares. La actividad geomorfológica durante el Dryas Reciente en la Península Ibérica se ha identificado mediante depósitos morrénicos, umbrales rocosos pulidos por el hielo, y glaciares rocosos, datados en la mayor parte de los casos mediante métodos cosmogénicos. Los mejores ejemplos de morrenas del Dryas Reciente se localizan en los Pirineos, donde se desarrollaron cortas lenguas glaciares de hasta 4 km de longitud en los macizos más elevados y numerosos glaciares de circo. También hay evidencias de pequeños glaciares de circo y glaciares rocosos en la Cordillera Cantábrica y en el Sistema Central (sierras de Gredos y Guadarrama), como indican umbrales rocosos y depósitos morrénicos en el frente de circos glaciares. En cambio, en Sierra Nevada, en el extremo meridional de la Península Ibérica, las únicas evidencias del Younger Dryas son glaciares rocosos que se desarrollaron durante el Dryas Antiguo y estuvieron funcionales durante todo el Dryas reciente.
The Younger Dryas (GS-1, entre 12, 9 y 11, 7 ka BP) was characterized by a remarkable declining in temperature at a global scale. The consequence was a moderate re-advance of glaciers that also affected the main ranges of the Iberian Peninsula. This paper reviews the available information on the location, evolution and extent of such glaciers. The geomorphological activity during the Younger Dryas in the Iberian Peninsula has been identified throughout the presence of morainic deposits (dated in most cases with cosmogenic exposure ages), rocky thresholds polished by the ice, and rock glaciers. The best examples of Younger Dryas moraines were found in the Central Pyrenees, with short ice tongues of up to 4 km in length in the highest massifs and a number of glacial cirques. There is also evidence of small cirque glaciers in the Cantabrian Range and the Central System Range (Gredos and Guadarrama sierras), as deduced by rocky thresholds and morainic deposits close to cirque headwalls. Conversely, in Sierra Nevada (southernmost sector of the Iberian Peninsula) the only evidence of the Younger Dryas is the presence of rock glaciers that were developed during the Oldest Dryas and survived during the Younger Dryas
The AMBRE project: A new synthetic grid of high-resolution FGKM stellar spectra
Large grids of synthetic spectra covering a widespread range of stellar
parameters are mandatory for different stellar and (extra-)Galactic physics
applications. Such large grids can be used for the automatic parametrisation of
stellar spectra such as that performed within the AMBRE project for which the
main goal is the stellar atmospheric parameters determination for the few
hundreds of thousands of archived spectra of four ESO spectrographs. To fulfil
the needs of AMBRE and future similar projects, we have computed a grid of
synthetic spectra over the whole optical domain for cool to very cool stars of
any luminosity with metallicities varying from 10-5 to 10 times the solar
metallicity, and considering large variations in the chemical content of the
{\alpha}-elements. New generation MARCS model atmospheres and the Turbospectrum
code for radiative transfer have been used. We have also taken into account as
complete as possible atomic and molecular linelists. A new grid of 16783 high
resolution spectra over the wavelength range 3000 to 12000 {\AA} has been
computed with a spectral resolution always larger than 150000. Normalised and
absolute flux versions are available over a wide range of stellar atmospheric
parameters for stars of FGKM spectral types. The covered parameters are
2500K\leqTeff\leq8000K, -0.5\leqlog(g)\leq5.5dex, -5.0\leq[M/H]\leq+1.0 dex and
five different values of the enrichment in {\alpha}-elements have been
considered (0.0, \pm0.2 dex and \pm0.4 dex around the standard values). This
grid is made publicly available through the POLLUX database (about 50% of the
spectra are already included in this database) and in FITS format upon request
to the authors.Comment: Accepted by A&
Taxonomic variations in the gut microbiome of gout patients with and without tophi might have a functional impact on urate metabolism
Objective: To evaluate the taxonomic composition of the gut microbiome in gout patients with and without tophi
formation, and predict bacterial functions that might have an impact on urate metabolism.
Methods: Hypervariable V3–V4 regions of the bacterial 16S rRNA gene from fecal samples of gout patients with
and without tophi (n=33 and n=25, respectively) were sequenced and compared to fecal samples from 53 healthy
controls. We explored predictive functional profles using bioinformatics in order to identify diferences in taxonomy
and metabolic pathways.
Results: We identifed a microbiome characterized by the lowest richness and a higher abundance of Phascolarctobacterium, Bacteroides, Akkermansia, and Ruminococcus_gnavus_group genera in patients with gout without tophi
when compared to controls. The Proteobacteria phylum and the Escherichia-Shigella genus were more abundant
in patients with tophaceous gout than in controls. Fold change analysis detected nine genera enriched in healthy
controls compared to gout groups (Bifdobacterium, Butyricicoccus, Oscillobacter, Ruminococcaceae_UCG_010, Lachnospiraceae_ND2007_group, Haemophilus, Ruminococcus_1, Clostridium_sensu_stricto_1, and Ruminococcaceae_
UGC_013). We found that the core microbiota of both gout groups shared Bacteroides caccae, Bacteroides stercoris ATCC
43183, and Bacteroides coprocola DSM 17136. These bacteria might perform functions linked to one-carbon metabo‑
lism, nucleotide binding, amino acid biosynthesis, and purine biosynthesis. Finally, we observed diferences in key
bacterial enzymes involved in urate synthesis, degradation, and elimination.
Conclusion: Our fndings revealed that taxonomic variations in the gut microbiome of gout patients with and with‑
out tophi might have a functional impact on urate metabolism.
Keywords: Gout, Gut microbiota, Uric acid metabolis
CALIFA, the Calar Alto Legacy Integral Field Area survey: I. Survey presentation
We present here the Calar Alto Legacy Integral Field Area (CALIFA) survey,
which has been designed to provide a first step in this direction.We summarize
the survey goals and design, including sample selection and observational
strategy.We also showcase the data taken during the first observing runs
(June/July 2010) and outline the reduction pipeline, quality control schemes
and general characteristics of the reduced data. This survey is obtaining
spatially resolved spectroscopic information of a diameter selected sample of
galaxies in the Local Universe (0.005< z <0.03). CALIFA has been
designed to allow the building of two-dimensional maps of the following
quantities: (a) stellar populations: ages and metallicities; (b) ionized gas:
distribution, excitation mechanism and chemical abundances; and (c) kinematic
properties: both from stellar and ionized gas components. CALIFA uses the PPAK
Integral Field Unit (IFU), with a hexagonal field-of-view of
\sim1.3\sq\arcmin', with a 100% covering factor by adopting a three-pointing
dithering scheme. The optical wavelength range is covered from 3700 to 7000
{\AA}, using two overlapping setups (V500 and V1200), with different
resolutions: R\sim850 and R\sim1650, respectively. CALIFA is a legacy survey,
intended for the community. The reduced data will be released, once the quality
has been guaranteed. The analyzed data fulfill the expectations of the original
observing proposal, on the basis of a set of quality checks and exploratory
analysis.
We conclude from this first look at the data that CALIFA will be an important
resource for archaeological studies of galaxies in the Local Universe.Comment: 32 pages, 29 figures, Accepted for publishing in Astronomy and
Astrophysic
Evaluation of Textural and Sensory Properties on Typical Spanish Small Cakes Designed Using Alternative Flours
[EN] The objective of this study was to evaluate the effect of wheat flour substitution with toasted corn, quinoa, and sorghum flours on the overall perception and texture of typical Spanish small cakes
named madeleine. In order to evaluate these characteristics, a texture profile analysis (TPA) and a sensory analysis were carried out.
TPA showed that the replacement of wheat flour by sorghum flour did not affect significantly texture parameters of cakes. Hedonic sensory tests were also conducted revealing that the cake prepared
with sorghum flour was highly appreciated by the consumers as it got scores similar to traditional cakes made with wheat flour.Casas Moreno, MDM.; Barreto Palacios, VJ.; González Carrascosa, R.; Iborra Bernad, MDC.; Andrés Bello, MD.; Martínez Monzó, J.; García-Segovia, P. (2015). Evaluation of Textural and Sensory Properties on Typical Spanish Small Cakes Designed Using Alternative Flours. Journal of Culinary Science and Technology. 13(1):19-28. doi:10.1080/15428052.2014.952475S1928131Baldwin, R. R., Baldry, R. P., & Johansen, R. G. (1972). Fat systems for bakery products. Journal of the American Oil Chemists’ Society, 49(8), 473-477. doi:10.1007/bf02582482Beleia, A., Miller, R. A., & Hoseney, R. C. (1996). Starch Gelatinization in Sugar Solutions. Starch - Starke, 48(7-8), 259-262. doi:10.1002/star.19960480705Brannan, G. L., Setser, C. S., Kemp, K. E., Seib, P. A., & Roozeboom, K. (2001). Sensory Characteristics of Grain Sorghum Hybrids with Potential for Use in Human Food. Cereal Chemistry Journal, 78(6), 693-700. doi:10.1094/cchem.2001.78.6.693Cauvain, S. P., & Young, L. S. (Eds.). (2006). Baked Products. doi:10.1002/9780470995907Chieh, C. (s. f.). Water. Bakery Products, 211-232. doi:10.1002/9780470277553.ch11Conforti, F. D. (s. f.). Cake Manufacture. Bakery Products, 393-410. doi:10.1002/9780470277553.ch22Ghotra, B. S., Dyal, S. D., & Narine, S. S. (2002). Lipid shortenings: a review. Food Research International, 35(10), 1015-1048. doi:10.1016/s0963-9969(02)00163-1Kiosseoglou, V., & Paraskevopoulou, A. (s. f.). Eggs. Bakery Products, 161-172. doi:10.1002/9780470277553.ch8Lai, H.-M., & Lin, T.-C. (s. f.). Bakery Products: Science and Technology. Bakery Products, 3-68. doi:10.1002/9780470277553.ch1Lau, M. ., Tang, J., & Paulson, A. . (2000). Texture profile and turbidity of gellan/gelatin mixed gels. Food Research International, 33(8), 665-671. doi:10.1016/s0963-9969(00)00111-3LINDLEY, M. G. (1987). Sucrose in baked products. Nutrition Bulletin, 12(1), 41-45. doi:10.1111/j.1467-3010.1987.tb00011.xMastromatteo, M., Chillo, S., Iannetti, M., Civica, V., & Del Nobile, M. A. (2011). Formulation optimisation of gluten-free functional spaghetti based on quinoa, maize and soy flours. International Journal of Food Science & Technology, 46(6), 1201-1208. doi:10.1111/j.1365-2621.2011.02613.xOreopoulou, V. (s. f.). Fat Replacers. Bakery Products, 193-210. doi:10.1002/9780470277553.ch10Peressini, D., Pin, M., & Sensidoni, A. (2011). Rheology and breadmaking performance of rice-buckwheat batters supplemented with hydrocolloids. Food Hydrocolloids, 25(3), 340-349. doi:10.1016/j.foodhyd.2010.06.012Sanz, T., Salvador, A., Baixauli, R., & Fiszman, S. M. (2009). Evaluation of four types of resistant starch in muffins. II. Effects in texture, colour and consumer response. European Food Research and Technology, 229(2), 197-204. doi:10.1007/s00217-009-1040-1Taylor, J. R. N., Schober, T. J., & Bean, S. R. (2006). Novel food and non-food uses for sorghum and millets. Journal of Cereal Science, 44(3), 252-271. doi:10.1016/j.jcs.2006.06.009Wilderjans, E., Luyts, A., Brijs, K., & Delcour, J. A. (2013). Ingredient functionality in batter type cake making. Trends in Food Science & Technology, 30(1), 6-15. doi:10.1016/j.tifs.2013.01.001Wilderjans, E., Pareyt, B., Goesaert, H., Brijs, K., & Delcour, J. A. (2008). The role of gluten in a pound cake system: A model approach based on gluten–starch blends. Food Chemistry, 110(4), 909-915. doi:10.1016/j.foodchem.2008.02.079Wilson, N. L. W. (2011). How the Cookie Crumbles: A Case Study of Gluten-Free Cookies and Random Utility. American Journal of Agricultural Economics, 94(2), 576-582. doi:10.1093/ajae/aar081Zhu, J.-H., Yang, X.-Q., Ahmad, I., Li, L., Wang, X.-Y., & Liu, C. (2008). Rheological properties of κ-carrageenan and soybean glycinin mixed gels. Food Research International, 41(3), 219-228. doi:10.1016/j.foodres.2007.11.00
TRY plant trait database - enhanced coverage and open access
Plant traits-the morphological, anatomical, physiological, biochemical and phenological characteristics of plants-determine how plants respond to environmental factors, affect other trophic levels, and influence ecosystem properties and their benefits and detriments to people. Plant trait data thus represent the basis for a vast area of research spanning from evolutionary biology, community and functional ecology, to biodiversity conservation, ecosystem and landscape management, restoration, biogeography and earth system modelling. Since its foundation in 2007, the TRY database of plant traits has grown continuously. It now provides unprecedented data coverage under an open access data policy and is the main plant trait database used by the research community worldwide. Increasingly, the TRY database also supports new frontiers of trait-based plant research, including the identification of data gaps and the subsequent mobilization or measurement of new data. To support this development, in this article we evaluate the extent of the trait data compiled in TRY and analyse emerging patterns of data coverage and representativeness. Best species coverage is achieved for categorical traits-almost complete coverage for 'plant growth form'. However, most traits relevant for ecology and vegetation modelling are characterized by continuous intraspecific variation and trait-environmental relationships. These traits have to be measured on individual plants in their respective environment. Despite unprecedented data coverage, we observe a humbling lack of completeness and representativeness of these continuous traits in many aspects. We, therefore, conclude that reducing data gaps and biases in the TRY database remains a key challenge and requires a coordinated approach to data mobilization and trait measurements. This can only be achieved in collaboration with other initiatives
Grain Surface Models and Data for Astrochemistry
AbstractThe cross-disciplinary field of astrochemistry exists to understand the formation, destruction, and survival of molecules in astrophysical environments. Molecules in space are synthesized via a large variety of gas-phase reactions, and reactions on dust-grain surfaces, where the surface acts as a catalyst. A broad consensus has been reached in the astrochemistry community on how to suitably treat gas-phase processes in models, and also on how to present the necessary reaction data in databases; however, no such consensus has yet been reached for grain-surface processes. A team of ∼25 experts covering observational, laboratory and theoretical (astro)chemistry met in summer of 2014 at the Lorentz Center in Leiden with the aim to provide solutions for this problem and to review the current state-of-the-art of grain surface models, both in terms of technical implementation into models as well as the most up-to-date information available from experiments and chemical computations. This review builds on the results of this workshop and gives an outlook for future directions
Search for composite and exotic fermions at LEP 2
A search for unstable heavy fermions with the DELPHI detector at LEP is
reported. Sequential and non-canonical leptons, as well as excited leptons and
quarks, are considered. The data analysed correspond to an integrated
luminosity of about 48 pb^{-1} at an e^+e^- centre-of-mass energy of 183 GeV
and about 20 pb^{-1} equally shared between the centre-of-mass energies of 172
GeV and 161 GeV. The search for pair-produced new leptons establishes 95%
confidence level mass limits in the region between 70 GeV/c^2 and 90 GeV/c^2,
depending on the channel. The search for singly produced excited leptons and
quarks establishes upper limits on the ratio of the coupling of the excited
fermio
Search for charginos in e+e- interactions at sqrt(s) = 189 GeV
An update of the searches for charginos and gravitinos is presented, based on
a data sample corresponding to the 158 pb^{-1} recorded by the DELPHI detector
in 1998, at a centre-of-mass energy of 189 GeV. No evidence for a signal was
found. The lower mass limits are 4-5 GeV/c^2 higher than those obtained at a
centre-of-mass energy of 183 GeV. The (\mu,M_2) MSSM domain excluded by
combining the chargino searches with neutralino searches at the Z resonance
implies a limit on the mass of the lightest neutralino which, for a heavy
sneutrino, is constrained to be above 31.0 GeV/c^2 for tan(beta) \geq 1.Comment: 22 pages, 8 figure
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