125 research outputs found
The relationship between Mathematical Utility Theory and the Integrability Problem: some arguments in favour
The resort to utility-theoretical issues will permit us to propose a constructive procedure for deriving a homogeneous of degree one, continuous function that gives raise to a primitive demand function under suitably mild conditions. This constitutes the first elementary proof of a necessary and sufficient condition for an integrability problem to have a solution by continuous (subjective utility) functions. Such achievement reinforces the relevance of a technique that was succesfully formalized in Alcantud and Rodríguez-Palmero (2001). The analysis of these two works exposes deep relationships between two apparently separate fields: mathematical utility theory and the revealed preference approach to the integrability problem.Strong Axiom of Homothetic Revelation; revealed preference; continuous homogeneous of degree one utility; integrability of demand.
Una aproximación a las representaciones del alumnado sobre el Universo
This study explains how the children from secondary school (age 14-18) represent the structure of the universe and the way it may be useful in daily teaching. The results obtained describe the same conceptualization difficulties that the younger students already have, as well as the need for studying deeply the process for learning of those students as far as, having dealt with those contents before, they have not reached the expected scientific knowledge concerning the topic
Surface nanostructuring of TiO2 thin films by ion beam irradiation
This work reports a procedure to modify the surface nanostructure of TiO2 anatase thin films through ion beam irradiation with energies in the keV range. Irradiation with N+ ions leads to the formation of a layer with voids at a depth similar to the ion-projected range. By setting the ion-projected range a few tens of nanometers below the surface of the film, well-ordered nanorods appear aligned with the angle of incidence of the ion beam. Slightly different results were obtained by using heavier (S+) and lighter (B+) ions under similar conditions
An oleuropein β-glucosidase from olive fruit is involved in determining the phenolic composition of virgin olive oil
Phenolic composition of virgin olive oil is determined by the enzymatic and/or chemical reactions that take place during olive fruit processing. Of these enzymes, β-glucosidase activity plays a relevant role in the transformation of the phenolic glycosides present in the olive fruit, generating different secoiridoid derivatives. The main goal of the present study was to characterize olive fruit β-glucosidase genes and enzymes responsible for the phenolic composition of virgin olive oil. To achieve that, we have isolated an olive β-glucosidase gene from cultivar Picual (OepGLU), expressed in Nicotiana benthamiana leaves and purified its corresponding recombinant enzyme. Western blot analysis showed that recombinant OepGLU protein is detected by an antibody raised against the purified native olive mesocarp β-glucosidase enzyme, and exhibits a deduced molecular mass of 65.0 kDa. The recombinant OepGLU enzyme showed activity on the major olive phenolic glycosides, with the highest levels with respect to oleuropein, followed by ligstroside and demethyloleuropein. In addition, expression analysis showed that olive GLU transcript level in olive fruit is spatially and temporally regulated in a cultivar-dependent manner. Furthermore, temperature, light and water regime regulate olive GLU gene expression in olive fruit mesocarp. All these data are consistent with the involvement of OepGLU enzyme in the formation of the major phenolic compounds present in virgin olive oil
Effects of Bifidobacterium longum Subsp. infantis CECT 7210 and Lactobacillus rhamnosus HN001, Combined or Not With Oligofructose-Enriched Inulin, on Weaned Pigs Orally Challenged With Salmonella Typhimurium
Salmonella is a common causative agent of enteric disease and is developing mechanisms of resistance to antimicrobials. Probiotics, such as bifidobacteria and lactobacilli, and prebiotic fibers are a potential alternative to counteract this pathogen as they have demonstrated effectiveness in preventing its adhesion, reducing intestinal damage, and enhancing the host immune system. Furthermore, the benefits are expected to be potentiated when these compounds are administered together. A trial was performed to evaluate the efficacy of two probiotic strains (Bifidobacterium longum subsp. infantis CECT 7210 (Laboratorios Ordesa S.L.) and Lactobacillus rhamnosus HN001, combined or not with a prebiotic containing oligofructose-enriched inulin, against Salmonella Typhimurium. Ninety-six piglets (28 days old) were distributed into 32 pens assigned to 5 treatments: one non-challenged (control diet, CTR+) and four challenged: control diet (CTR−) or supplemented with probiotics (>3 × 10 10 cfu/kg each strain, PRO), prebiotic (5%, PRE), or their combination (SYN). After 1 week of adaptation, animals were orally challenged with Salmonella Typhimurium. Feed intake, weight, and clinical signs were recorded. On days 4 and 8 post-inoculation (PI), one animal per pen was euthanized, and samples from blood, digestive content, and ileal tissues were collected to determine Salmonella counts, fermentation products, ileal histomorphology, and serum TNF-α and Pig-MAP concentrations. The effect of the oral challenge was evidenced by animal performance, fecal consistency, and intestinal architecture. Regarding the experimental treatments, animals belonging to the PRO group experienced a faster clearance of the pathogen, with more pigs being negative to its excretion at the end of the study and recovering the impaired ileal villi/crypt ratio more rapidly. Animals receiving the PRE diet showed a lower intestinal colonization by Salmonella, with no countable levels (<3 cfu/g) in any of the analyzed samples, and an augmented immune response suggested by serum Pig-MAP concentrations. Treatments including the prebiotic (PRE and SYN) showed similar changes in the fermentation pattern, with an increase in the molar percentage of valeric acid concentration in the colon. The SYN group, however, did not show any of the outcomes registered for PRO and PRE in Salmonella colonization or in immunity markers, suggesting the lack of synbiotic action in this animal model. Further research is needed to better understand the complex mechanisms behind these effects
Effects of a high-fat-diet supplemented with probiotics and ω3-fatty acids on appetite regulatory neuropeptides and neurotransmitters in a pig model
The pig is a valuable animal model to study obesity in humans due to the physiological similarity between humans and pigs in terms of digestive and associated metabolic processes. The dietary use of vegetal protein, probiotics and omega-3 fatty acids is recommended to control weight gain and to fight obesity-associated metabolic disorders. Likewise, there are recent reports on their beneficial effects on brain functions. The hypothalamus is the central part of the brain that regulates food intake by means of the production of food intake-regulatory hypothalamic neuropeptides, as neuropeptide Y (NPY), orexin A and pro-opiomelanocortin (POMC), and neurotransmitters, such as dopamine and serotonin. Other mesolimbic areas, such as the hippocampus, are also involved in the control of food intake. In this study, the effect of a high fat diet (HFD) alone or supplemented with these additives on brain neuropeptides and neurotransmitters was assessed in forty-three young pigs fed for 10 weeks with a control diet (T1), a high fat diet (HFD, T2), and HFD with vegetal protein supplemented with Bifidobacterium breve CECT8242 alone (T3) or in combination with omega-3 fatty acids (T4). A HFD provoked changes in regulatory neuropeptides and 3,4-dihydroxyphenylacetic acid (DOPAC) in the hypothalamus and alterations mostly in the dopaminergic system in the ventral hippocampus. Supplementation of the HFD with B. breve CECT8242, especially in combination with omega-3 fatty acids, was able to partially reverse the effects of HFD. Correlations between productive and neurochemical parameters supported these findings. These results confirm that pigs are an appropriate animal model alternative to rodents for the study of the effects of HFD on weight gain and obesity. Furthermore, they indicate the potential benefits of probiotics and omega-3 fatty acids on brain function.info:eu-repo/semantics/acceptedVersio
Fungal microbiota from rain water and pathogenicity of Fusarium species isolated from atmospheric dust and rainfall dust
In order to determine the presence of Fusarium spp. in atmospheric dust and rainfall dust, samples were collected during September 2007, and July, August, and October 2008. The results reveal the prevalence of airborne Fusarium species coming from the atmosphere of the South East coast of Spain. Five different Fusarium species were isolated from the settling dust: Fusarium oxysporum, F. solani, F. equiseti, F. dimerum, and F. proliferatum. Moreover, rainwater samples were obtained during significant rainfall events in January and February 2009. Using the dilution-plate method, 12 fungal genera were identified from these rainwater samples. Specific analyses of the rainwater revealed the presence of three species of Fusarium: F. oxysporum, F. proliferatum and F. equiseti. A total of 57 isolates of Fusarium spp. obtained from both rainwater and atmospheric rainfall dust sampling were inoculated onto melon (Cucumis melo L.) cv. Piñonet and tomato (Lycopersicon esculentum Mill.) cv. San Pedro. These species were chosen because they are the main herbaceous crops in Almeria province. The results presented in this work indicate strongly that spores or propagules of Fusarium are able to cross the continental barrier carried by winds from the Sahara (Africa) to crop or coastal lands in Europe. Results show differences in the pathogenicity of the isolates tested. Both hosts showed root rot when inoculated with different species of Fusarium, although fresh weight measurements did not bring any information about the pathogenicity. The findings presented above are strong indications that long-distance transmission of Fusarium propagules may occur. Diseases caused by species of Fusarium are common in these areas. They were in the past, and are still today, a problem for greenhouses crops in Almería, and many species have been listed as pathogens on agricultural crops in this region. Saharan air masses dominate the Mediterranean regions. The evidence of long distance dispersal of Fusarium spp. by atmospheric dust and rainwater together with their proved pathogenicity must be taken into account in epidemiological studies
Contenidos, metodología y alumnado : una valoración crítica de la enseñanza en BUP y COU
The aim of this study was to compare the interest of the students in Natural Science in front of three other subjects such as Mathematics, Literature and Geography &amp; History. The selected items of the contents of every subject, and the importance of teaching as an influential factor on students were also studied. The results showed that both the selection of the contents and the methods should have been modified
Professor of Physiology; M. Castell, PhD, Professor of Physiology; C. Pelegrí, PhD, Professor of Physiology
ABSTRACT. Objective. To determine the immunomodulatory effects of the anti-rat CD28 monoclonal antibody (Mab) JJ316 on the onset of rat adjuvant arthritis (AA). JJ316 is a superagonistic Mab that induces polyclonal T cell proliferation in the absence of T cell receptor (TCR) ligation and promotes the expansion of regulatory T cells. Methods. Female Wistar rats in which AA was induced were treated with JJ316 on Day 0 and Day 9 postinduction. A parallel treatment with JJ319, a "conventional" CD28-specific Mab that costimulates anti-TCR triggered proliferation, was performed. Severity of arthritis was monitored by means of an arthritic score, and by recording hindpaw volume and body weight increases. Serum antibodies against the AA-inducing mycobacteria were also determined by ELISA. To ascertain the effect of JJ316 on T lymphocytes in vivo, blood CD4+CD45RC high (Th1-like) and CD4+CD45RC low (Th2-like) cells were analyzed by flow cytometry, and the relative levels of interleukin 2 (IL-2), IL-10, and interferon-γ (IFN-γ) mRNA in synovial tissue were measured by real-time reverse transcriptionpolymerase chain reaction. Results. JJ316 efficiently prevented the inflammatory process of AA. This effect was associated with a specific decrease in the blood CD4+CD45RC high /CD4+CD45RC low T cell ratio and high IL-10 mRNA expression in the synovia. In addition, anti-mycobacteria antibody levels decreased in JJ316 treated animals. In contrast, administration of the conventional anti-CD28 Mab JJ319 did not improve inflammation. Conclusion. JJ316, a stimulatory CD28-specific Mab known to promote Th2 function and the expansion of regulatory T cells, provides effective protection from AA. (J Rheumatol 2006;33:110-8
Influencia del grado de deformación en frío en el tamaño de grano y en la resistencia a la corrosión del acero F-1110
En este trabajo se ha estudiado la evolución que sufre el tamaño de grano del acero al carbono F-1110 para distintos grados de deformación en frío, a partir de su estado de recocido, libre de tensiones y de cualquier acritud. La deformación en frío se ha conseguido utilizando una máquina universal de ensayos y los distintos grados de deformación se han ajustado al intervalo comprendido entre la estricción y la rotura. La posterior observación al microscopio óptico de las zonas deformadas, previa preparación metalográfica, nos ha permitido medir la variación en el tamaño de grano. Finalmente, se ha evaluado la influencia del grado de deformación en la resistencia a la corrosión del acero
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