113 research outputs found

    True colour Denisyuk-Type hologram recording in Bayfol HX self-developing photopolymer

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    True colour Denisyuk-type hologram recording of diffusing objects in Bayfol® HX 102 self-developing photopolymer has been studied. In a first stage, monochromatic Denisyuk holograms of a standard white diffuser (Spectralon) have been recorded using lasers with wavelengths 442, 532 and 633 nm to determine the optimum exposure that gives maximum efficiency. The recording of holograms from a diffusing object has the particularity that intermodulation noise due to interference between waves arriving from different object points reduces effective index modulation. A maximum effective efficiency of 80% has been reached for monochromatic recording. In a second stage, a set of experiments has been carried out to determine the adequate relation of exposure for the recording of a Denisyuk hologram of the standard white diffuser with the three lasers simultaneously to get the maximum efficiency for each wavelength. With the determined optimal exposure, a hologram of a polychromatic diffusing object has been recorded, obtaining a good visual coincidence between hologram and original object

    Preference by Donkeys and Goats among Five Mediterranean Forest Species : Implications for Reducing Fire Hazard

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    During the second half of the 20th century, European countries experienced an increase in their forest area due to the global change. Consequently, there has been an increase in large forest fires, mainly in the Mediterranean basin, and this has forced the development of several types of prevention programs. One of them is the control of the understory by livestock. In this sense, browsing with a combination of donkeys and goats could be a good option, as both animals usually feed on forest species. However, little is known about their preferences for the key species of the Mediterranean forest. Using a cafeteria test, the preferences and consumption of both animals have been determined for five typical species of the Mediterranean forest, such as Quercus ilex, Pinus halepensis, Phillyrea latifolia, Rubus ulmifolius, and Brachypodium retusum. Results showed that donkeys and goats could act complementarily in the reduction of the fuel biomass of forests. Donkeys appear to act more on fine fuel, such as B. retusum, and goats on the more pyrophyte species, in this case P. halepensis. In addition, given that donkeys are at severe risk of extinction in Europe, this role of providing ecosystem services could contribute to their conservation. Despite this study only showing that goats and donkeys would consume all five presented plant species and that there are some differences in consumption during a short-term test, it constitutes a useful first step for conservation and fire prevention in the Mediterranean forests

    Dynamics of gravity driven three-dimensional thin films on hydrophilic-hydrophobic patterned substrates

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    We investigate numerically the dynamics of unstable gravity driven three-dimensional thin liquid films on hydrophilic-hydrophobic patterned substrates of longitudinal stripes and checkerboard arrangements. The thin film can be guided preferentially on hydrophilic longitudinal stripes, while fingers develop on adjacent hydrophobic stripes if their width is large enough. On checkerboard patterns, the film fingering occurs on hydrophobic domains, while lateral spreading is favoured on hydrophilic domains, providing a mechanism to tune the growth rate of the film. By means of kinematical arguments, we quantitatively predict the growth rate of the contact line on checkerboard arrangements, providing a first step towards potential techniques that control thin film growth in experimental setups.Comment: 30 pages, 12 figure

    Diagnostic Performance of a Fecal Immunochemical Test-Based Colorectal Cancer Screening Program According to Ambient Temperature and Humidity

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    Hemoglobin degradation can be affected by ambient temperature and humidity. How this modifies the advanced neoplasia detection rate and interval cancer rate remains understudied. We conducted a retrospective study and analyzed the impact of ambient temperature and humidity on the fecal immunochemical test (FIT) positivity rate, detection rate for advanced neoplasia, and interval colorectal cancer (CRC). The results of our study indicated that at >24 degrees C, the positivity rate was lower, whereas the detection rate of the FIT for advanced neoplasia and the interval cancer detection rate were not affected, probably because we have adopted measures to minimize the impact of ambient temperature on FIT sensitivity. Humidity did not affect FIT sensitivity. The results emphasize the importance of organizational efforts on the procedures along the screening process (such as the cold chain) to minimize the effect of seasonal variations in temperature on the positivity rate. Exposure of the fecal immunochemical test (FIT) to different ambient temperatures and humidity is unavoidable in population-based screening programs in Southern European countries, and it could lead to a decrease in target colorectal lesions. The objective was to evaluate the effect of ambient temperature and humidity on the FIT sensitivity in a population-based screening program for colorectal cancer (CRC) using an ecological design. The retrospective cohort included individuals aged 50-69 years who participated in CRC screening (Barcelona) from 2010-2015, and were followed until 2017 to identify interval CRCs. The positivity rate, and detection rates for advanced polyps and CRC were compared according to ambient temperature, humidity, and quarters of the year. A positive FIT was defined as the detection of >= 20 mu g Hb/g in feces. The monthly ambient temperature and humidity were recorded on the day that the FIT was performed. In total, 92,273 FIT results from 53,860 participants were analyzed. The FIT positivity rate was lower at >24 degrees C than at <= 24 degrees C (p = 0.005) but was not affected by humidity. The temperature's impact on positivity did not lead to a decrease in the FIT detection rate for advanced neoplasia or the interval cancer detection rate in a program where the samples were refrigerated until the analysis and screening invitations were discontinued in July and August

    Experiencia en capacitación y transferencia de herramientas didácticas sobre el uso racional de la energía y energías renovables

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    Se presentan las actividades desarrolladas en el marco del Proyecto de Extensión “Capacitación y transferencia sobre mejoramiento de condiciones ambientales, uso racional de energía y energías renovables”, llevado a cabo por docentes de la cátedra de Acondicionamiento Ambiental I de la Facultad de Arquitectura y Urbanismo de la Universidad Nacional de Tucumán, con el fin de impulsar la incorporación de la temática energético-ambiental a través de contenidos y actividades en escuelas públicas de Tucumán. Las actividades planteadas buscan promover el uso racional de la energía y la aplicación de energías renovables para ahorrar energía en la escuela y en la propia casa. Se trabajó en forma articulada con la Secretaria de Medio Ambiente de la Provincia, quien a través de su “Equipo Provincial de Educación Ambiental” brindó la vinculación y coordinación con las escuelas de la Provincia. En la presentación se muestran los resultados de una experiencia piloto desarrollada con participación de directivos, docentes y alumnos de 4º y 5º grado de la escuela primaria Capitán de los Andes de nuestra provincia. Las actividades incluyeron el diseño y prueba de herramientas didácticas y transferencia del material para la implementación de la experiencia por parte de los docentes de la escuela. La experiencia piloto abarcó el planteo de contenidos y actividades en relación a las necesidades detectadas en la curricula actual, dictado de clases con apoyo audiovisual y talleres demostrativos de sistemas con aplicación de energía solar. Los principales contenidos abordados en las clases incluyen los tipos y formas de aplicación de la energía, su relación con el cambio climático. Sistemas y aplicación de energías renovables, la energía en los edificios, uso racional, posible ahorro y mejoras en las condiciones de habitabilidad. Sistemas con aplicación de energía renovable, con utilización de diferentes materiales y accesorios. También se incluyen talleres con modelos demostrativos de dos sistemas con energía solar: Horno Solar y Colector de Agua, con preparación de alimentos y de agua caliente sanitaria, factibles de ser construidos y utilizados en la escuela y en la propia casa. Conclusiones: Las actividades desarrolladas permitieron conocer las necesidades, transferir conocimiento y desarrollar pensamiento crítico en el contexto de la educación escolar primaria de Tucumán, en pro de una conciencia ambiental más eficiente que considere y evalúe en profundidad, sobre bases científicas, la incorporación de energías renovables y formas de uso racional de la energía en los ámbitos donde desarrolla diariamente sus actividades.

    Neuregulin-1 promotes functional improvement by enhancing collateral sprouting in SOD1G93A ALS mice and after partial muscle denervation

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    Altres ajuts: Fundació La Marato-TV3(TV3201428-10), AFM-Telethon (Nrg14ALS)Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease characterized by progressive degeneration of motoneurons, which is preceded by loss of neuromuscular connections in a "dying back" process. Neuregulin-1 (Nrg1) is a neurotrophic factor essential for the development and maintenance of neuromuscular junctions, and Nrg1 receptor ErbB4 loss-of-function mutations have been reported as causative for ALS. Our main goal was to investigate the role of Nrg1 type I (Nrg1-I) in SOD1G93A mice muscles. We overexpressed Nrg1-I by means of an adeno-associated viral (AAV) vector, and investigated its effect by means of neurophysiological techniques assessing neuromuscular function, as well as molecular approaches (RT-PCR, western blot, immunohistochemistry, ELISA) to determine the mechanisms underlying Nrg1-I action. AAV-Nrg1-I intramuscular administration promoted motor axon collateral sprouting by acting on terminal Schwann cells, preventing denervation of the injected muscles through Akt and ERK1/2 pathways. We further used a model of muscle partial denervation by transecting the L4 spinal nerve. AAV-Nrg1-I intramuscular injection enhanced muscle reinnervation by collateral sprouting, whereas administration of lapatinib (ErbB receptor inhibitor) completely blocked it. We demonstrated that Nrg1-I plays a crucial role in the collateral reinnervation process, opening a new window for developing novel ALS therapies for functional recovery rather than preservation

    Allometry and Ecology of the Bilaterian Gut Microbiome.

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    Classical ecology provides principles for construction and function of biological communities, but to what extent these apply to the animal-associated microbiota is just beginning to be assessed. Here, we investigated the influence of several well-known ecological principles on animal-associated microbiota by characterizing gut microbial specimens from bilaterally symmetrical animals (Bilateria) ranging from flies to whales. A rigorously vetted sample set containing 265 specimens from 64 species was assembled. Bacterial lineages were characterized by 16S rRNA gene sequencing. Previously published samples were also compared, allowing analysis of over 1,098 samples in total. A restricted number of bacterial phyla was found to account for the great majority of gut colonists. Gut microbial composition was associated with host phylogeny and diet. We identified numerous gut bacterial 16S rRNA gene sequences that diverged deeply from previously studied taxa, identifying opportunities to discover new bacterial types. The number of bacterial lineages per gut sample was positively associated with animal mass, paralleling known species-area relationships from island biogeography and implicating body size as a determinant of community stability and niche complexity. Samples from larger animals harbored greater numbers of anaerobic communities, specifying a mechanism for generating more-complex microbial environments. Predictions for species/abundance relationships from models of neutral colonization did not match the data set, pointing to alternative mechanisms such as selection of specific colonists by environmental niche. Taken together, the data suggest that niche complexity increases with gut size and that niche selection forces dominate gut community construction.IMPORTANCEThe intestinal microbiome of animals is essential for health, contributing to digestion of foods, proper immune development, inhibition of pathogen colonization, and catabolism of xenobiotic compounds. How these communities assemble and persist is just beginning to be investigated. Here we interrogated a set of gut samples from a wide range of animals to investigate the roles of selection and random processes in microbial community construction. We show that the numbers of bacterial species increased with the weight of host organisms, paralleling findings from studies of island biogeography. Communities in larger organisms tended to be more anaerobic, suggesting one mechanism for niche diversification. Nonselective processes enable specific predictions for community structure, but our samples did not match the predictions of the neutral model. Thus, these findings highlight the importance of niche selection in community construction and suggest mechanisms of niche diversification

    High Diversity at PRDM9 in Chimpanzees and Bonobos

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    BACKGROUND: The PRDM9 locus in mammals has increasingly attracted research attention due to its role in mediating chromosomal recombination and possible involvement in hybrid sterility and hence speciation processes. The aim of this study was to characterize sequence variation at the PRDM9 locus in a sample of our closest living relatives, the chimpanzees and bonobos. METHODOLOGY/PRINCIPAL FINDINGS: PRDM9 contains a highly variable and repetitive zinc finger array. We amplified this domain using long-range PCR and determined the DNA sequences using conventional Sanger sequencing. From 17 chimpanzees representing three subspecies and five bonobos we obtained a total of 12 alleles differing at the nucleotide level. Based on a data set consisting of our data and recently published Pan PRDM9 sequences, we found that at the subspecies level, diversity levels did not differ among chimpanzee subspecies or between chimpanzee subspecies and bonobos. In contrast, the sample of chimpanzees harbors significantly more diversity at PRDM9 than samples of humans. Pan PRDM9 shows signs of rapid evolution including no alleles or ZnFs in common with humans as well as signals of positive selection in the residues responsible for DNA binding. CONCLUSIONS AND SIGNIFICANCE: The high number of alleles specific to the genus Pan, signs of positive selection in the DNA binding residues, and reported lack of conservation of recombination hotspots between chimpanzees and humans suggest that PRDM9 could be active in hotspot recruitment in the genus Pan. Chimpanzees and bonobos are considered separate species and do not have overlapping ranges in the wild, making the presence of shared alleles at the amino acid level between the chimpanzee and bonobo species interesting in view of the hypothesis that PRDM9 plays a universal role in interspecific hybrid sterility
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