894 resultados para Moduli in modern mapping theory
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Selostus: Maanviljelijöiden altistuminen pölyille ja kaasuille nykyaikaisissa navetoissa
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The majority of terrestrial plants live in association with symbiotic fungi that facilitate mineral nutrient uptake. The oldest and most prevalent of these associations are the arbuscular mycorrhizal (AM) symbioses that first evolved approximately 400 million years ago, coinciding with the appearance of the first land plants. Crop domestication, in comparison, is a relatively recent event, beginning approximately 10000 years ago. How has the dramatic change from wild to cultivated ecosystems impacted AM associations, and do these ancient symbioses potentially have a role in modern agriculture? Here, we review recent advances in AM research and the use of breeding approaches to generate new crop varieties that enhance the agronomic potential of AM associations.
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We analyze the influence of the density dependence of the symmetry energy on the average excitation energy of the isoscalar giant monopole resonance (GMR) in stable and exotic neutron-rich nuclei by applying the relativistic extended Thomas-Fermi method in scaling and constrained calculations. For the effective nuclear interaction, we employ the relativistic mean field model supplemented by an isoscalar-isovector meson coupling that allows one to modify the density dependence of the symmetry energy without compromising the success of the model for binding energies and charge radii. The semiclassical estimates of the average energy of the GMR are known to be in good agreement with the results obtained in full RPA calculations. The present analysis is performed along the Pb and Zr isotopic chains. In the scaling calculations, the excitation energy is larger when the symmetry energy is softer. The same happens in the constrained calculations for nuclei with small and moderate neutron excess. However, for nuclei of large isospin the constrained excitation energy becomes smaller in models having a soft symmetry energy. This effect is mainly due to the presence of loosely-bound outer neutrons in these isotopes. A sharp increase of the estimated width of the resonance is found in largely neutron-rich isotopes, even for heavy nuclei, which is enhanced when the symmetry energy of the model is soft. The results indicate that at large neutron numbers the structure of the low-energy region of the GMR strength distribution changes considerably with the density dependence of the nuclear symmetry energy, which may be worthy of further characterization in RPA calculations of the response function.
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We study the contribution to vacuum decay in field theory due to the interaction between the long- and short-wavelength modes of the field. The field model considered consists of a scalar field of mass M with a cubic term in the potential. The dynamics of the long-wavelength modes becomes diffusive in this interaction. The diffusive behavior is described by the reduced Wigner function that characterizes the state of the long-wavelength modes. This function is obtained from the whole Wigner function by integration of the degrees of freedom of the short-wavelength modes. The dynamical equation for the reduced Wigner function becomes a kind of Fokker-Planck equation which is solved with suitable boundary conditions enforcing an initial metastable vacuum state trapped in the potential well. As a result a finite activation rate is found, even at zero temperature, for the formation of true vacuum bubbles of size M-1. This effect makes a substantial contribution to the total decay rate.
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The class of Schoenberg transformations, embedding Euclidean distances into higher dimensional Euclidean spaces, is presented, and derived from theorems on positive definite and conditionally negative definite matrices. Original results on the arc lengths, angles and curvature of the transformations are proposed, and visualized on artificial data sets by classical multidimensional scaling. A distance-based discriminant algorithm and a robust multidimensional centroid estimate illustrate the theory, closely connected to the Gaussian kernels of Machine Learning.
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We study the process of vacuum decay in quantum field theory focusing on the stochastic aspects of the interaction between long- and short-wavelength modes. This interaction results in a diffusive behavior of the reduced Wigner function describing the state of long-wavelength modes, and thereby to a finite activation rate even at zero temperature. This effect can make a substantial contribution to the total decay rate.
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Rare earth elements (REE), while not essential for the physiologic functions of animals, are ingested and incorporated in ppb concentrations in bones and teeth. Nd isotope compositions of modern bones of animals from isotopically distinct habitats demonstrate that the (143)Nd/(144)Nd of the apatite can be used as a fingerprint for bedrock geology or ambient water mass. This potentially allows the provenance and migration of extant vertebrates to be traced, similar to the use of Sr isotopes. Although REE may be enriched by up to 5 orders of magnitude during diagenesis and recrystallization of bone apatite, in vivo (143)Nd/(144)Nd may be preserved in the inner cortex of fossil bones or enamel. However, tracking the provenance of ancient or extinct vertebrates is possible only for well-preserved archeological and paleontological skeletal remains with in vivo-like Nd contents at the ppb-level. Intra-bone and -tooth REE analysis can be used to screen for appropriate areas. Large intra-bone Nd concentration gradients of 10(1)-10(3) are often measured. Nd concentrations in the inner bone cortex increase over timescales of millions of years, while bone rims may be enriched over millenial timescales. Nevertheless, epsilon(Nd) values are often similar within one epsilon(Nd) unit within a single bone. Larger intra-bone differences in specimens may either reflect a partial preservation of in vivo values or changing epsilon(Nd) values of the diagenetic fluid during fossilization. However, most fossil specimens and the outer rims of bones will record taphonomic (143)Nd/(144)Nd incorporated post mortem during diagenesis. Unlike REE patterns, (143)Nd/(144)Nd are not biased by fractionation processes during REE-uptake into the apatite crystal lattice, hence the epsilon(Nd) value is an important tracer for taphonomy and reworking. Bones and teeth from autochthonous fossil assemblages have small variations of +/- 1 epsilon(Nd) unit only. In contrast, fossil bones and teeth from over 20 different marine and terrestrial fossil sites have a total range of epsilon(Nd) values from -13.0 to 4.9 (n = 80), often matching the composition of the embedding sediment. This implies that the surrounding sediment is the source of Nd in the fossil bones and that the specimens of this study seem not to have been reworked. Differences in epsilon(Nd) values between skeletal remains and embedding sediment may either indicate reworking of fossils and/or a REE-uptake from a diagenetic fluid with non-sediment derived epsilon(Nd) values. The latter often applies to fossil shark teeth, which may preserve paleo-seawater values. Complementary to epsilon(Nd) values, (87)Sr/(86)Sr can help to further constrain the fossil provenance and reworking. (C) 2011 Elsevier Ltd. All rights reserved.
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Palvelukehitystoiminta sitoo huomattavan määrän resursseja ja on pitkäkestoista toimintaa. Innovatiivisuuteen tähtäämällä ja systemaattisella tuotekehitystyöllä yritys parantaa jatkuvuutta omassa liiketoiminnassaan. Alusta-ajattelu tuo uuden ulottuvuuden tuotteiden ja palveluiden kehitykseen. Alustan kehittäminen tukemaan tuote- ja palvelukehitystoimintaa ja yksinkertaistamaan tuote/palvelurakenteita antaa yrityksissä lisäpotentiaalia esimerkiksi lyhentyneiden kehitysaikojen, paremman kompleksisuuden hallinnan ja kustannustehokkuuden nousun myötä. Toimintojen tehostuminen yritystasolla saa aikaan mahdollisuuksien lisääntymisen nykyisillä liiketoimintasektoreilla. Palvelualustan kehityksellä päästään palvelurakenteen mallintamisen kautta parempaan liiketoiminnan hallitsemiseen ja systemaattisempaan tuotekehityksen läpivientiin. Palvelualustan yhtenä tärkeimpänä hyötynä on, että palvelun rakenteellisuus saadaan kuvattua alustaan. Lisäksi on tärkeää määritellä vastuutukset alustan kehityksessä, sekä pystyä mallintamaan informaation kulku (rajapinnat) prosesseissa.
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The variability observed in drug exposure has a direct impact on the overall response to drug. The largest part of variability between dose and drug response resides in the pharmacokinetic phase, i.e. in the dose-concentration relationship. Among possibilities offered to clinicians, Therapeutic Drug Monitoring (TDM; Monitoring of drug concentration measurements) is one of the useful tool to guide pharmacotherapy. TDM aims at optimizing treatments by individualizing dosage regimens based on blood drug concentration measurement. Bayesian calculations, relying on population pharmacokinetic approach, currently represent the gold standard TDM strategy. However, it requires expertise and computational assistance, thus limiting its large implementation in routine patient care. The overall objective of this thesis was to implement robust tools to provide Bayesian TDM to clinician in modern routine patient care. To that endeavour, aims were (i) to elaborate an efficient and ergonomic computer tool for Bayesian TDM: EzeCHieL (ii) to provide algorithms for drug concentration Bayesian forecasting and software validation, relying on population pharmacokinetics (iii) to address some relevant issues encountered in clinical practice with a focus on neonates and drug adherence. First, the current stage of the existing software was reviewed and allows establishing specifications for the development of EzeCHieL. Then, in close collaboration with software engineers a fully integrated software, EzeCHieL, has been elaborated. EzeCHieL provides population-based predictions and Bayesian forecasting and an easy-to-use interface. It enables to assess the expectedness of an observed concentration in a patient compared to the whole population (via percentiles), to assess the suitability of the predicted concentration relative to the targeted concentration and to provide dosing adjustment. It allows thus a priori and a posteriori Bayesian drug dosing individualization. Implementation of Bayesian methods requires drug disposition characterisation and variability quantification trough population approach. Population pharmacokinetic analyses have been performed and Bayesian estimators have been provided for candidate drugs in population of interest: anti-infectious drugs administered to neonates (gentamicin and imipenem). Developed models were implemented in EzeCHieL and also served as validation tool in comparing EzeCHieL concentration predictions against predictions from the reference software (NONMEM®). Models used need to be adequate and reliable. For instance, extrapolation is not possible from adults or children to neonates. Therefore, this work proposes models for neonates based on the developmental pharmacokinetics concept. Patients' adherence is also an important concern for drug models development and for a successful outcome of the pharmacotherapy. A last study attempts to assess impact of routine patient adherence measurement on models definition and TDM interpretation. In conclusion, our results offer solutions to assist clinicians in interpreting blood drug concentrations and to improve the appropriateness of drug dosing in routine clinical practice.
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Ressenya del llibre: 'Gender Inequalities, Households and the Production of Well-being in Modern Europe'
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Tutkielmassa eritellään Norman Faircloughin kriittisen diskurssianalyysin teoriaa ja siihen kohdistettua kritiikkiä. Pyrkimyksenä on sovittaa näitä erilaisia näkemyksiä keskenään ja tarjota ratkaisuja yhteen kiriittisen diskurssianalyysin keskeiseen ongelmaan eli emansipaation (sosiaalisten epäkohtien tunnistamisen ja ratkaisemisen) puutteellisuuteen. Teoriaosuudesta esiin nousevia mahdollisuuksia sovelletaan tekstianalyysiin. Tutkimuksen kohteena on teksti Rebuilding America’s Defenses: Strategy, Forces and Resources For a New Century ja jossain määrin sen tuottanut järjestö Project for the New American Century. Näitä tarkastellaan ennen kaikkea sosiaalisina ilmiöinä ja suhteessa toisiinsa. Faircloughin mallin suurimmiksi ongelmiksi muodostuvat perinteinen käsitys kielestä, jonka mukaan kielen järjestelmän abstraktit ja sisäiset suhteet ovat tärkeimpiä, sekä ideologinen vastakkainasettelu kritiikin lähtökohtana. Ensimmäinen johtaa kielellisten tutkimustulosten epätyydyttävään kykyyn selittää sosiaalisia havaintoja ja jälkimmäinen poliittiseen tai maailmankatsomukselliseen väittelyyn, joka ei mahdollista uusia näkemyksiä. Tutkielman lopputulema on, että keskittymällä asiasisältöön kielen rakenteen sijasta ja ymmärtämällä tekstin tuottaja yksittäisenä, rajattuna sosiaalisena toimijana voidaan analyysiin saada avoimuutta ja täsmällisyyttä. Kriittiinen diskurssianalyysi kaipaa tällaista näkemystä kielellisten analyysien tueksi ja uudenlaisen relevanssin löytääkseen.