Showing papers by "Technical University of Madrid published in 2002"
TL;DR: In this paper, the elastic constants of the ensemble of spheres embedded in a continuous and isotropic elastic matrix were computed through the finite element analysis of the three-dimensional periodic unit cells, whose size was chosen as a compromise between the minimum size required to obtain accurate results in the statistical sense and the maximum one imposed by the computational cost.
Abstract: Three-dimensional cubic unit cells containing 30 non-overlapping identical spheres randomly distributed were generated using a new, modified random sequential adsortion algorithm suitable for particle volume fractions of up to 50% The elastic constants of the ensemble of spheres embedded in a continuous and isotropic elastic matrix were computed through the finite element analysis of the three-dimensional periodic unit cells, whose size was chosen as a compromise between the minimum size required to obtain accurate results in the statistical sense and the maximum one imposed by the computational cost Three types of materials were studied: rigid spheres and spherical voids in an elastic matrix and a typical composite made up of glass spheres in an epoxy resin The moduli obtained for different unit cells showed very little scatter, and the average values obtained from the analysis of four unit cells could be considered very close to the “exact” solution to the problem, in agreement with the results of Drugan and Willis (J Mech Phys Solids 44 (1996) 497) referring to the size of the representative volume element for elastic composites They were used to assess the accuracy of three classical analytical models: the Mori–Tanaka mean-field analysis, the generalized self-consistent method, and Torquato's third-order approximation
516 citations
TL;DR: In this paper, the experimental results of mechanical behavior under static and dynamic loads of specimens made of concrete filled with small volumetric fractions of crushed tyre rubber and polypropylene short fibres, at 7 and 28 days, are compared with results of concrete specimens of similar features without fibres or tyre.
358 citations
TL;DR: A conclusion to this study is that there is no completely mature methodological proposal for building ontologies, since there are some important activities and techniques that are missing in all these methodologies.
Abstract: The use of methodologies in software and knowledge engineering is very extensive due to their important advantages. In the case of the development of ontologies, until now, several methodological proposals have been presented for building ontologies. Some of these methodologies are designed for building ontologies from scratch or reusing other ontologies without modifying them, concretely, the following cases can be mentioned: the Cyc methodology, the approach proposed by Uschold and King, Gruninger and Fox's methodology, the KACTUS methodology, METHONTOLOGY and the SENSUS methodology. There is even a proposal for re-engineering ontologies, and several proposals for collaborative construction of ontologies.In this article, we describe the methodologies and check their degree of maturity, contrasting them with respect to the IEEE standard for software development. Before this, we justify to what extent this standard can be used. A conclusion to this study is that there is no completely mature methodological proposal for building ontologies, since there are some important activities and techniques that are missing in all these methodologies. However, all the methodologies do not have the same degree of maturity. In fact, METHONTOLOGY is a very mature methodology. The other conclusion of this article is that, although work to unify proposals can be interesting, maybe several approaches should coexist.
290 citations
TL;DR: It is discussed that all HAK transporters may mediate K+ transport, but probably not only in the plasma membrane, and the involvement of HAKtransporters in root K+ uptake is demonstrated.
Abstract: Plants take up large amounts of K(+) from the soil solution and distribute it to the cells of all organs, where it fulfills important physiological functions. Transport of K(+) from the soil solution to its final destination is mediated by channels and transporters. To better understand K(+) movements in plants, we intended to characterize the function of the large KT-HAK-KUP family of transporters in rice (Oryza sativa cv Nipponbare). By searching in databases and cDNA cloning, we have identified 17 genes (OsHAK1-17) encoding transporters of this family and obtained evidence of the existence of other two genes. Phylogenetic analysis of the encoded transporters reveals a great diversity among them, and three distant transporters, OsHAK1, OsHAK7, and OsHAK10, were expressed in yeast (Saccharomyces cerevisiae) and bacterial mutants to determine their functions. The three transporters mediate K(+) influxes or effluxes, depending on the conditions of the experiment. A comparative kinetic analysis of HAK-mediated K(+) influx in yeast and in roots of K(+)-starved rice seedlings demonstrated the involvement of HAK transporters in root K(+) uptake. We discuss that all HAK transporters may mediate K(+) transport, but probably not only in the plasma membrane. Transient expression of the OsHAK10-green fluorescent protein fusion protein in living onion epidermal cells targeted this protein to the tonoplast.
288 citations
TL;DR: In this paper, the long-term effects of tillage systems on water stability of pre-wetted and air dried aggregates, soil organic carbon (SOC) stratification and crop production were studied in a Vertic Luvisol with a loam texture.
Abstract: Under semiarid Mediterranean climatic conditions, soils typically have low organic matter content and weak structure resulting in low infiltration rates. Aggregate stability is a quality indicator directly related to soil organic matter, which can be redistributed within soil by tillage. Long-term effects (1983–1996) of tillage systems on water stability of pre-wetted and air dried aggregates, soil organic carbon (SOC) stratification and crop production were studied in a Vertic Luvisol with a loam texture. Tillage treatments included conventional tillage (CT), minimum tillage (MT) and zero tillage (ZT) under winter wheat ( Triticum aestivum L.) and vetch ( Vicia sativa L.) rotation (W–V), and under continuous monoculture of winter wheat or winter barley ( Hordeum vulgare L.) (CM). Aggregate stability of soil at a depth of 0–5 cm was much greater when 1–2 mm aggregates were vacuum wetted prior to sieving (83%) than when slaked (6%). However, slaking resulted in tillage effects that were consistent with changes in SOC. Aggregate stability of slaked aggregates was greater under ZT than under CT or MT in both crop rotations (i.e., 11% vs. 3%, respectively). SOC under ZT tended to accumulate in the surface soil layer (0–5 and 5–10 cm) at the expense of deeper ones. At depths of 10–20 and 20–30 cm no differences in SOC were encountered among tillage systems, but CT exhibited the highest concentration at 30–40 cm depth. Nevertheless, when comparisons were made on mass basis (Mg ha −1 ), significant differences in stocked SOC were observed at depths of 0–10 and 0–20 cm, where ZT had the highest SOC content in both rotations. The stock of SOC to a depth of 40 cm, averaged across crop rotations, was greater under ZT (43 Mg ha −1 ) than under CT (41 Mg ha −1 ) and MT (40 Mg ha −1 ) although these figures were not significantly different. Likewise, no significant differences were encountered in the stock of SOC to a depth of 40 cm among crop rotations (i.e., 42 Mg ha −1 for W–V vs. 40 Mg ha −1 for CM). Crop production with wheat–vetch and continuous cereal showed no differences among tillage systems. Yields were strongly limited by the environmental conditions, particularly the amount of rainfall received in the crop growth season and its distribution. Similar yield and improved soil properties under ZT suggests that it is a more sustainable system for the semiarid Mediterranean region of Spain.
279 citations
TL;DR: This work provides one of the necessary links to unify simulation with experiments in alpha-Fe and ferritic alloys subject to high-energy particle irradiation.
Abstract: We propose a comprehensive mechanism for the formation and growth of $〈100〉$ interstitial loops in $\ensuremath{\alpha}$-Fe. This mechanism reconciles long-standing experimental observations of these defects in irradiated ferritic materials with recent atomistic simulations of collision cascades and defect cluster properties in Fe, in which highly mobile $\frac{1}{2}〈111〉$ clusters are seen to be the dominant feature. Hence, this work provides one of the necessary links to unify simulation with experiments in $\ensuremath{\alpha}$-Fe and ferritic alloys subject to high-energy particle irradiation.
182 citations
TL;DR: An estimate of the spontaneous mutation rate of tobacco mosaic virus using an 804-base cognate mutational target, the viral MP gene that encodes the movement protein (MP), is reported and the first unbiased riboviral mutational spectrum is presented.
Abstract: Estimates of spontaneous mutation rates for RNA viruses are few and uncertain, most notably due to their dependence on tiny mutation reporter sequences that may not well represent the whole genome. We report here an estimate of the spontaneous mutation rate of tobacco mosaic virus using an 804-base cognate mutational target, the viral MP gene that encodes the movement protein (MP). Selection against newly arising mutants was countered by providing MP function from a transgene. The estimated genomic mutation rate was on the lower side of the range previously estimated for lytic animal riboviruses. We also present the first unbiased riboviral mutational spectrum. The proportion of base substitutions is the same as that in a retrovirus but is lower than that in most DNA-based organisms. Although the MP mutant frequency was 0.02-0.05, 35% of the sequenced mutants contained two or more mutations. Therefore, the mutation process in populations of TMV and perhaps of riboviruses generally differs profoundly from that in populations of DNA-based microbes and may be strongly influenced by a subpopulation of mutator polymerases.
170 citations
TL;DR: The feasibility of the DIABTel system in clinical routine use and its potential benefits for diabetes care are demonstrated: improving the availability of information necessary for therapy adjustments; offering new physician-patient communication tools; increasing patient empowerment and education; and showing a positive trend towards improving the metabolic control of patients.
169 citations
TL;DR: It is described here that BPBF, a barley transcription factor of the DOF (DNA-Binding with One Finger) class, previously shown to be an activator of reserve protein encoding genes during development, also has a role in the control of hydrolase genes following seed germination.
Abstract: Functional analyses of a number of hydrolase gene promoters, induced by gibberellin (GA) in aleurone cells following germination, have identified a GA-responsive complex as a tripartite element containing a pyrimidine box motif 5'-CCTTTT-3'. We describe here that BPBF, a barley (Hordeum vulgare) transcription factor of the DOF (DNA-Binding with One Finger) class, previously shown to be an activator of reserve protein encoding genes during development, also has a role in the control of hydrolase genes following seed germination. Northern-blot, reverse transcriptase-polymerase chain reaction, and in situ hybridization analyses evidenced that the transcripts of the BPBF-encoding gene (Pbf), besides being present during endosperm development, are also expressed in aleurone cells of germinated seeds where they are induced by GA, an effect counteracted by abscisic acid. Electrophoretic mobility shift assays have shown that the BPBF protein binds specifically to the pyrimidine box motif in vitro within the different sequence contexts that naturally occur in the promoters of genes encoding a cathepsin B-like protease (Al21) and a low-isoelectric point alpha-amylase (Amy2/32b), both induced in the aleurone layers in response to GA. In transient expression experiments, BPBF repressed transcription of the Al21 promoter in GA-treated barley aleurone layers and reverted the GAMYB-mediated activation of this protease promoter.
169 citations
TL;DR: In this article, the role of externalities in promoting industrial growth in Spanish regions is discussed, and the analysis is restricted to dynamic externalities using productivity, instead of labor, using data from the Spanish Industry Survey from 1978 to 1992 for 26 manufacturing branches.
166 citations
TL;DR: This paper describes and compares integrated TRYS and TRYS autonomous agents, two multiagent systems that perform decision support for real-time traffic management in the urban motorway network around Barcelona, and develops some conclusions respecting the general applicability of multiagent architectures for intelligent traffic management.
Abstract: This paper reports our experiences with agent-based architectures for intelligent traffic management systems. We describe and compare integrated TRYS and TRYS autonomous agents, two multiagent systems that perform decision support for real-time traffic management in the urban motorway network around Barcelona. Both systems draw upon traffic management agents that use similar knowledge-based reasoning techniques in order to deal with local traffic problems. Still, the former achieves agent coordination based on a traditional centralized mechanism, while in the latter coordination emerges upon the lateral interaction of autonomous traffic management agents. We evaluate the potentials and drawbacks of both multiagent architectures for the domain, and develop some conclusions respecting the general applicability of multiagent architectures for intelligent traffic management.
TL;DR: In this paper, the microstructural changes induced by the dispersion of the ceramic reinforcements are described, followed by two sections devoted to an analysis of the micromechanisms of cyclic deformation from the micro-structural and mechanical viewpoints.
TL;DR: It is shown that the energy spectrum fluctuations of quantum systems can be formally considered as a discrete time series and the power spectrum behavior of such a signal for different systems suggests the following conjecture.
Abstract: It is shown that the energy spectrum fluctuations of quantum systems can be formally considered as a discrete time series. The power spectrum behavior of such a signal for different systems suggests the following conjecture: The energy spectra of chaotic quantum systems are characterized by 1/f noise.
TL;DR: In this article, a numerical procedure for mixed mode fracture of quasi-brittle materials is presented, based on the cohesive crack approach and extended to mixed-mode fracture, and the model is incorporated into a commercial finite element code by an user subroutine.
TL;DR: The results obtained during the project demonstration show the feasibility of the T-IDDM telemedicine service, and seem to substantiate the hypothesis that the use of the system could present an advantage in the management of insulin dependent diabetic patients, by improving communications and, potentially, clinical outcomes.
TL;DR: Accumulation of VFL transcripts in cell-proliferating regions suggests a role for VFL not only in flower meristem specification, but also in the maintenance of indeterminacy before the differentiation of derivatives of the apicalMeristem: flowers, leaves, or tendrils.
Abstract: The flowering process in grapevine (Vitis vinifera) takes place in buds and extends for two consecutive growing seasons. To understand the genetic and molecular mechanisms underlying this process, we have characterized grapevine bud development, cloned the grapevine FLORICAULA/LEAFY (FLO/LFY) ortholog, VFL, and analyzed its expression patterns during vegetative and reproductive development. Flowering induction takes place during the first season. Upon induction, the shoot apical meristem begins to produce lateral meristems that will give rise to either inflorescences or tendrils. During the second season, after a winter dormancy period, buds reactivate and inflorescence meristems give rise to flower meristems. VFL is expressed in lateral meristems that give rise to inflorescence and flower meristems, consistent with a role in reproductive development. Furthermore, VFL is also detected in other meristematic regions such as the vegetative shoot apical meristem and the lateral meristems that will give rise to tendrils. VFL is also expressed in leaf primordia and in growing leaf margins until later stages of development. Accumulation of VFL transcripts in cell-proliferating regions suggests a role for VFL not only in flower meristem specification, but also in the maintenance of indeterminacy before the differentiation of derivatives of the apical meristem: flowers, leaves, or tendrils.
TL;DR: In this article, the SIESTA program was used to find the isolated intermediate band when one Ti atom replaces the position of one As (or P) atom in the crystal structure.
Abstract: A metallic isolated band in the middle of the band gap of several III-V semiconductors has been predicted as photovoltaic materials with the possibility of providing substantially enhanced efficiencies. We have investigated the electronic band structures and lattice constants of ${\mathrm{Ga}}_{n}{\mathrm{As}}_{m}\mathrm{M}$ and ${\mathrm{Ga}}_{n}{\mathrm{P}}_{m}\mathrm{M}$ with $\mathrm{M}=\mathrm{Sc},$ Ti, V, and Cr, to identify whether this isolated band is likely to exist by means of accurate calculations. For this task, we use the SIESTA program, an ab initio periodic density-functional method, fully self consistent in the local-density approximation. Norm-conserving, nonlocal pseudopotentials and confined linear combination of atomic orbitals have been used. We have carried out a case study of ${\mathrm{Ga}}_{n}{\mathrm{As}}_{m}\mathrm{Ti}$ and ${\mathrm{Ga}}_{n}{\mathrm{P}}_{m}\mathrm{Ti}$ energy-band structure including analyses of the effect of the basis set, fine k-point mesh to ensure numerical convergence, structural parameters, and generalized gradient approximation for exchange and correlation corrections. We find the isolated intermediate band when one Ti atom replaces the position of one As (or P) atom in the crystal structure. For this kind of compound we show that the intermediate band relative position inside the band gap and width are sensitive to the dynamic relaxation of the crystal and the size of the basis set.
TL;DR: In this paper, the authors report the results of molecular dynamics simulations of self-interstitial cluster diffusion in pure \ensuremath{\alpha}-Fe and in a dilute Fe--1.0 at.
Abstract: We report the results of molecular dynamics simulations of self-interstitial cluster diffusion in pure \ensuremath{\alpha}-Fe and in a dilute Fe--1.0 at. % Cu alloy for a number of cluster sizes, $nl~20.$ We find that the effect of this oversized substitutional solute is to enhance the three-dimensional character of small-cluster diffusion and to impact the general cluster diffusion properties. We explain this through a mechanism directly based on the interactions between the atomic displacement field of the Cu atoms and the self-interstitial clusters. Based on these results, we derive simple power laws for the extrapolation of migration energies and diffusion prefactors to larger sizes, required for longer-range microstructural evolution models. These laws represent an improvement over current parametrizations used in previous calculations.
TL;DR: Forcibly reeled silkworm (Bombyx mori) silk was used to study how exposure to a degumming treatment (boiling in distilled water for 30 min) affects tensile properties as mentioned in this paper.
Abstract: Forcibly reeled silkworm (Bombyx mori) silk was used to study how exposure to a degumming treatment (boiling in distilled water for 30 min) affects tensile properties. Because forcibly reeled and naturally spun fibers exhibit comparable mechanical behavior, the results can be generalized to material obtained conventionally from cocoons. The effects of degumming include: a decrease in the initial elastic modulus, a decrease in the stress at the proportional limit (yield strength), a change in the qualitative shape of force-displacement curves, and significant qualitative and quantitative variability in force-displacement data from samples subjected to nominally identical degumming histories. Immersion in water at room temperature or heating in air at 100°C for 30 min are both qualitatively equivalent to a 30-min degumming treatment in boiling water, in terms of the effect on silk tensile properties. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 1431–1437, 2002; DOI 10.1002/app.10366
TL;DR: In this paper, the impact of the aggregate-matrix interface on the macroscopic fracture parameters of concrete is investigated, and the results show that concretes with the same matrix and aggregates, and similar behaviour under uniaxial compression, can give very different fracture responses.
TL;DR: Dietary manipulation of the diet together with management changes will reduce to manageable levels the problems associated with the ban of use of growth promoters in broiler feeds.
Abstract: The restrictions in the use of in-feed antibiotics and proteins of animal origin in many European countries have increased the incidence of enteric disorders in poultry. Management and dietary changes have been suggested to reduce the negative effects of enteritis on broiler performance and carcass quality. Practices used in this respect are enhancement of the development of the gastrointestinal tract, improvement of nutrient digestibility, and modification of the conditions of the intestinal contents to promote a balanced growth of native flora. The most promising areas of research are the use of enzymes and the inclusion of whole grains in the diet. Areas of interest, but needing large amounts of basic information, include studies on the interrelationship between diet composition and the microbiota within the gastrointestinal tract. Also, the influence of processing of diets and ingredients and of the inclusion of natural additives on digestive physiology and microflora growth deserves attention. In conclusion, dietary manipulation of the diet together with management changes will reduce to manageable levels the problems associated with the ban of use of growth promoters in broiler feeds.
TL;DR: In this article, the fracture surfaces of three different silks produced by two silkworms (A. atlas) and Bombyx mori (B. mori)) and one spider (Argiope trifasciata) were analyzed through a scanning electron microscope.
TL;DR: The degree of variation of seed oil content and fatty acid oil composition is assessed in two experiments designed to study the effect of the factors: plant population, crop year and experiment location.
Abstract: Cynara cardunculus L. has been recognised as an energy crop for rainfed lands with Mediterranean climates. For energy purposes, it is grown as a permanent crop and the whole aerial biomass produced over the annual growth cycle is harvested every year. In this work, the potential of C. cardunculus L. as an oil crop is studied in a perennial cultivation system. The degree of variation of seed oil content and fatty acid oil composition is assessed in two experiments designed to study the effect of the factors: plant population, crop year and experiment location. The range of values of seed oil content was greater for the multilocal experiment (20.0–31.6%) than for the experiment on populations (22.0–28.8%), but the effect of the agricultural year was noticed in both experiments. There were significant differences in the 18 populations experiment and a group of 5 populations was identified as rich in seed oil (>26%). Seed presscake was analysed and as a result the use of this material as fertiliser or as animal feed was proposed. Finally, the degree of variation of fatty acid oil composition—studied for the factors population, location and year—turned out to be rather small. Cynara oil profile was characterised in terms of major fatty acids as: 10.7% palmitic, 3.7% stearic, 25.0% oleic and 59.7% linoleic.
TL;DR: To adapt the CROPGRO model to simulate the growth and yield of faba bean, a systematic procedure was followed to develop relationships and values for the species and cultivar files and showed optimum yields from early winter sowing at Cordoba and latewinter sowing in northern Europe.
Abstract: Crop growth models are valuable tools for integrating our understanding of physiological processes and for hypothesizing and evaluating crop management strategies. Our objective was to adapt the CROPGRO model to simulate the growth and yield of faba bean (Vicia faba L.). The CROPGRO model simulates different grain legume species using external parameter files that describe species process sensitivity to environment plus files describing cultivar differences. Specific objectives were to develop a species file and one cultivar file for faba bean based on: (i) values and relationships from the literature and (ii) comparison with observed growth data on faba bean grown in Cordoba (Spain). A systematic procedure was followed to develop relationships and values for the species and cultivar files. Base temperatures for processes of this cool-season legume are typically between 0 to 2°C for photosynthetic, vegetative, and reproductive processes while corresponding optimum temperatures vary from 22 to 30°C. After adaptation, the model accurately predicted total crop dry matter accumulation, pod mass, and partitioning to plant components. High seed yields of faba bean exceeding 6000 kg ha -1 were predicted in agreement with observed data. Sensitivity analyses on sowing date showed optimum yields from early winter sowing at Cordoba and late winter sowing in northern Europe. Adapting an existing mechanistic model such as CROPGRO had advantages because many processes were similar across species and well simulated. The primary adaptation required was to change the cardinal temperature sensitivities of growth processes, based on faba bean literature or by analogy to other species.
Proceedings Article•
01 Jun 2002TL;DR: Some of the major challenges the Semantic Web community faces in the coming years are identified, and solution directions are outlined.
Abstract: The Semantic Web has attracted a diverse, but significant, community of researchers, institutes and companies, all sharing the belief that one day it will have as big an impact on life as currently the WWW/Internet has We share that vision, based on the ever-increaseing need to reduce information overload, and to increase task delegation to software agents However, there is still a long way to go before the Semantic Web dream comes true. We identify some of the major challenges the community faces in the coming years, and we outline solution directions. The major challenges concern: (i) the avalilability of content, (ii) ontology availability, development and evolution, (iii) scalability, (iv) multilinguality, (v)visualization to reduce information overload, an (vi) stability of Semantic Web languages
TL;DR: A new SPI method, called MESOPYME, which main focus is to reduce effort and time on the SPI implementation stage, based on a concept called Action Package, whose components are described in Section 2.1.
Abstract: During the last few years, many Software Process Improvement methods (SPI) have been presented to increase the quality of products and services provided by a software organization. Current Software Process Improvement (SPI) methods (i.e. ISO 15504, CBA-IPI, …), are difficult to apply to Small and Medium-sized Enterprises (SMES) due to the costs (financial, time, and resource) associated with their application. Also, these methods are principally focused on the assessment stage. This paper presents a new SPI method, called MESOPYME, which main focus is to reduce effort and time on the SPI implementation. This method focuses on the improvement implementation stage, which is based on a concept called Action Package, whose components are described (in Section 2.1.). The results obtained in the application of a Requirements Engineering Action Package in three organizations are also presented.
TL;DR: In this paper, two optimization criteria, minimum weight and minimum entropy generation, are simultaneously applied to deduce the main geometric characteristics of the two finned cross-flow heat exchangers that the environmental control system (ECS) of commercial aircraft normally incorporate.
TL;DR: It is shown that the Schizosaccharomyces pombe CTA3 is a K(+)-efflux ATPase, and that other fungi are furnished with Na(+)"efflux" ATPases, which also pump Na( +), and that these fungal ATPases form a phylogenetic group, IID or ENA, among P-type ATPases.
Abstract: Potassium is the most abundant cation in cells. Therefore, plant-associated fungi and intracellular parasites are permanently or circumstantially exposed to high K+ and must avoid excessive K+ accumulation activating K+ efflux systems. Because high K+ and high pH are compatible in natural environments, free-living organisms cannot keep a permanent transmembrane ΔpH and cannot rely only on K+/H+ antiporters, as do mitochondria. This study shows that the Schizosaccharomyces pombe CTA3 is a K+-efflux ATPase, and that other fungi are furnished with Na+-efflux ATPases, which also pump Na+. All these fungal ATPases, including those pumping only Na+, form a phylogenetic group, IID or ENA, among P-type ATPases. By searching in databases and partial cloning of ENA genes in species of Zygomycetes and Basidiomycetes, the authors conclude that probably all fungi have these genes. This study indicates that fungal K+- or Na+-ATPases evolved from an ancestral K+-ATPase, through processes of gene duplication. In yeast hemiascomycetes these duplications have occurred recently and produced bifunctional ATPases, whereas in Neurospora, and probably in other euascomycetes, they occurred earlier in evolution and produced specialized ATPases. In Schizosaccharomyces, adaptation to Na+ did not involve the duplication of the K+-ATPase and thus it retains an enzyme which is probably close to the original one. The parasites Leishmania and Trypanosoma have ATPases phylogenetically related to fungal K+-ATPases, which are probably functional homologues of the fungal enzymes.
TL;DR: The frequency-dependent nature of diffraction acts as a kind of dispersion that modifies the pulse front surface, its group velocity, the envelope form, and the carrier frequency, and these changes can be straightforwardly quantified.
Abstract: Basic concepts of three-dimensional wave packets are applied to the description of transverse effects on the propagation of ultrashort (femtosecond) pulses. The frequency-dependent nature of diffraction acts as a kind of dispersion that modifies the pulse front surface, its group velocity, the envelope form, and the carrier frequency. If the diffracted field in the monochromatic case is known, these changes can be straightforwardly quantified. Finding the propagated pulsed beam field reduces to a well-known and simpler problem of one-dimensional pulse propagation with group velocity dispersion. The method is applied to pulsed Gaussian beams and pulsed Bessel beams. Anomalous pulse front behavior, including superluminality in pulsed Gaussian beams is found. The carrier phase at any point of space is calculated.
TL;DR: A linear and quadratic effect of dietary NDF and the degree of lignification of NDF on VFA concentration was found, indicating a positive effect of high levels of low lignified fibre on caecal VFA.
Abstract: The aim of this work was to determine the main factors that affect caecal pH, the caecal concentrations and molar proportions of volatile fatty acids (VFA) and the weight of caecal contents. The database was constituted of data (n = 92) from three laboratories that included the mentioned traits and the chemical composition and nutritive value of the diets. The laboratory affected caecal pH (P < 0.001) probably because of the differences in sampling time among them. Dietary uronic acids (UA) were measured in 21 diets and were negatively correlated with caecal pH and positively with caecal VFA concentration and the proportion of propionic acid (P = 0.004, 0.06 and 0.03, respec- tively). When UA was removed from the model, no other chemical characteristics significantly af- fected caecal pH, and digestible NDF was the variable which was the best correlated with it (R 2 = 0.58; P < 0.001). Only one laboratory detected a relationship between caecal pH and caecal concentrations of VFA (P = 0.044) and N-NH3 (P = 0.14), which accounted for 12% of the variabil- ity observed in caecal pH. A linear and quadratic effect of dietary NDF and the degree of lignification of NDF on VFA concentration was found (R 2 = 0.56; P < 0.001), indicating a positive effect of high levels of low lignified fibre on caecal VFA. The weight of caecal contents was quadratically influ- enced by dietary NDF (R 2 = 0.39; P < 0.001). It was also linearly affected by the degree of lignifi- cation of NDF (P < 0.001). Dry matter intake was negatively correlated with caecal content weight ( P< 0.001; R 2 = 0.44), once the effects of the laboratory and dietary digestible energy concentration