1,592 research outputs found

    Roaring high and low: composition and possible functions of the Iberian stag's vocal repertoire

    Get PDF
    We provide a detailed description of the rutting vocalisations of free-ranging male Iberian deer (Cervus elaphus hispanicus, Hilzheimer 1909), a geographically isolated and morphologically differentiated subspecies of red deer Cervus elaphus. We combine spectrographic examinations, spectral analyses and automated classifications to identify different call types, and compare the composition of the vocal repertoire with that of other red deer subspecies. Iberian stags give bouts of roars (and more rarely, short series of barks) that are typically composed of two different types of calls. Long Common Roars are mostly given at the beginning or at the end of the bout, and are characterised by a high fundamental frequency (F0) resulting in poorly defined formant frequencies but a relatively high amplitude. In contrast, Short Common Roars are typically given in the middle or at the end of the bout, and are characterised by a lower F0 resulting in relatively well defined vocal tract resonances, but low amplitude. While we did not identify entirely Harsh Roars (as described in the Scottish red deer subspecies (Cervus elaphus scoticus), a small percentage of Long Common Roars contained segments of deterministic chaos. We suggest that the evolution of two clearly distinct types of Common Roars may reflect divergent selection pressures favouring either vocal efficiency in high pitched roars or the communication of body size in low-pitched, high spectral density roars highlighting vocal tract resonances. The clear divergence of the Iberian red deer vocal repertoire from those of other documented European red deer populations reinforces the status of this geographical variant as a distinct subspecies

    Alternative analysis to perturbation theory

    Full text link
    We develop an alternative approach to time independent perturbation theory in non-relativistic quantum mechanics. The method developed has the advantage to provide in one operation the correction to the energy and to the wave function, additionally we can analyze the time evolution of the system. To verify our results, we apply our method to the harmonic oscillator perturbed by a quadratic potential. An alternative form of the Dyson series, in matrix form instead of integral form, is also obtained.Comment: 12 pages, no figure

    Injertos osteocondrales congelados en el conejo: Estudio experimental

    Get PDF
    Con el propósito de analizar un protocolo de congelación de cartílago completo estudiando y la viabilidad del cartílago tas la implantación se ha realizado un estudio experimental en 60 rodillas de 45 conejos de Nueva Zelanda en población no genéticamente pura. Se extrajeron injertos osteocartilaginosos de 4 mm de diámetro y 2-3 mm de espesor, incluyendo cartílago articular y hueso subcondral que fueron sometidos a congelación lenta hasta -196º en Planer Kryo-10, Serie II, Controlled Rate Freezers, siguiendo un descenso de temperatura controlada bajo crioprotección con Dimetilsulfóxido, propanodiol y sacarosa. Posteriormente fueron descongelados e implantados en cóndilos femorales. Los injertos evolucionaron a tejido amorfo acelular y pasados los 2 meses, tras la incorporación del componente óseo se desarrolló tejido ibrocartilaginoso de sustitución. El presente estudio indica que el cartílago articular congelado no mantiene su viabilidad tras la implantación.The purpose of this study was to analyze a protocol for freezing whole cartilage and to study the viability of cartilage after the implant in 60 knees of 45 New Zealand rabbits from a genetically impure population. Osteocartilaginous implants were removed, measuring 4 mm in diameter and 2-3 mm thickness, inclunding the articular cartilage and the suchondral bone, and slow freezing up -196º using Planer Kyro-10, Series II, Controlled Rate Freezers, following a controlled drop in temperature under cyrso-protection with Dimethylsulfoxide, propanediol and sacarose. After thawing grafts were implanted in femoral condyles. The implants evolves into an acellular amorphous tissue and after 2 months, period in which the incorporation of the osseous compound occurs, substitute fibrocartilaginous tiusse develops. This study shows that frozen articular cartilage does not remain viable after implant

    Assessment of quality of life in oral cancer

    Get PDF
    Quality of life (QL) in oral cancer patients has become one of the most important parameters to consider in the diagnosis and post-treatment follow-up. The purpose of this article has been to review the papers published that study the QL in oral cancer patients, the different QL questionnaires used, the clinical results obtained, and the systematic revisions available in the indexed literature for the last 10 years. The term QL appears as a keyword in an increasing number of articles throughout the past 10 years; however, few studies focus on oral cancer. Most of them assess all head and neck cancers, which conform to a heterogeneous group with several different features depending on location (oral cavity, oropharynx, larynx, hypopharynx, nasopharynx and salivary glands). Most studies evaluate QL in short periods of time, normally within the first year after the diagnosis. Series do not discern between different therapeutic options, and they generally center on Northern European or Northern American populations. There are few instruments translated and validated into Spanish that measure QL, a fundamental characteristic to link QL to own patients? socio-cultural parameters. Data related with QL are mostly related to patient (age, sex, co-morbidity), tumour (location, size), and treatment (surgical treatment, radiotherapy association, reconstruction, cervical dissection, and/or feeding tube). Nowadays QL?s assessment is considered an essential component of an oral cancer patient as well as the survival, morbidity and years free of disease. Although many aspects related to QL in oral cancer patients have been published throughout the past 10 years, more systematic research is needed to be able to apply it on a daily basis

    Understanding the open circuit voltage in organic solar cells on the basis of a donor-acceptor abrupt (p-n++) heterojunction

    Get PDF
    By using electrical characterization and classical solid state semiconductor device theory, we demonstrate that the open circuit voltage (V oc ) in organic solar cells based on non-intentional doped semiconductors is fundamentally limited by the built-in potential (V bi ) originated at a donor-acceptor abrupt (p-n ++ ) heterojunction in case of selective contacts. Our analysis is validated using P3HT:PCBM devices fabricated in our research group. We also demonstrate that such a result can be generalized using data already reported in literature for fullerene-based solar cells. Finally, we show that the dependence of V oc on the device contacts can be understood in terms of the potential barriers formed by the Fermi level alignment of semiconductors at the heterojunction and at the Schottky junctions

    Parameterisation and Optimisation of a Hand-Rake Sweeper: Application in Olive Picking

    Get PDF
    Olive picking is one of the most common social agricultural activities in many regions of Andalusia where the predominant crop is the traditional olive grove. The machinery used includes shakers, blowers and essential, low-cost hand-rake sweepers. The latter are generally used by the women of the squads to sweep the olives that fall from the trees. This article is focused on the design and optimisation of a hand-rake sweeper, in terms of durability and cost, for the picking of olives and other fruits, such as almonds, which are currently the main alternative to nonperennial crops in Andalusia. A parametric design of a hand-rake sweeper was created for this application using the design software CATIA, and its most vulnerable points were analysed in terms of effectiveness with varying design parameters, conducting usage simulations with ANSYS for a light material such as polypropylene. The maximum von Mises stress of the whole structure was 155.81 MPa. Using ANSYS, the dimension parameters of the hand-rake sweeper structure were optimised. The modified design was analysed again, showing a reduction of maximum tensions of 10.06%, as well as a decrease in its maximum elongations (0.0181 mm)

    Open clusters or their remnants: B and V photometry of NGC 1901 and NGC 1252

    Get PDF
    Photometry in the B and V bands is presented for the southern stellar groups NGC 1901 and NGC 1252. NGC 1901 is often described as an open cluster while NGC 1252 consists of a concentration of about 20 stars centered approx 20' north of the original New General Catalogue coordinates, and at the southwest edge of the large region previously assigned to this object in the literature. NGC 1901 has a clear main sequence and shares similarities with the Hyades. We derive a reddening value E(B-V) = 0.04, a distance from the Sun d = 0.45 kpc (Z = -0.23 kpc) and an age 0.6 +/- 0.1 Gyr. NGC 1901 is conclusively a physical system, dynamically comparable to or more evolved than the Hyades. The colour- magnitude diagram of NGC 1252 suggests a turnoff and main sequence, and a total of 12 probable members. We simulated the Galactic field colour-magnitude diagram in the same direction and found it to be a poor match to NGC 1252, suggesting that NGC 1252 is not a field fluctuation. Isochrone fitting to the probable members is consistent with E(B-V) = 0.02, a distance from the Sun d = 0.64 kpc (Z = -0.46 kpc) and an age 3 +/- 1 Gyr. NGC 1252 cannot be ruled out as a physical group with the available data. If so, evidence is found that it is not a classical open cluster, but rather an open cluster remnant.Comment: 25 pages, 11 Postscript figures, accepted for A&

    Correction: Porous monoliths synthesized via polymerization of styrene and divinyl benzene in nonaqueous deep-eutectic solvent-based HIPEs (RSC Advances (2015) 5 (23255-23260) DOI: 10.1039/C5RA02374B)

    Get PDF
    © 2018 The Royal Society of Chemistry. The authors regret that there was an error in the results and discussion section of the original article. On page 23257, the text read, The surfactant employed here was sorbitan monooleate . This should have read, The surfactant employed here was sorbitan stearate . The Royal Society of Chemistry apologises for these errors and any consequent inconvenience to authors and readers

    In vitro wood decay of teak (Tectona grandis) by Rigidoporus cf. microporus (Meripiliaceae, Polyporales, Basidiomycota)

    Get PDF
    The use of exotic species like teak for industry demands has increased over the last decades in Central America, however its vulnerability to decay by saprophytic fungi has not been well studied. Among these fungi, Rigidoporus spp. have been described as white rotters of dead hardwoods and conifers worldwide. In Costa Rica, R. microporus has been found growing on teak stumps. The aim of this study was to determine the effects of this white rot fungus on the chemical, mechanical and physical properties of teak wood from trees of different ages. Six and ten year old sapwood and heartwood samples were used in the assays. Severe anatomical damage and the highest weight and resistance losses were observed on 6 yr. old sapwood samples. There was an increase in the quantity of soluble materials in 1% NaOH (relative values) and lignin content in all the samples analyzed, after 3 months exposure and up to the end of the experiment. Mass loss reduction and increased resistance of wood to compressive strength parallel to the grain were related to both the type of wood and the age of the tree. Knowledge of the potential damage that this fungus can cause to teak wood might help in a better selection of wood and developing more effective protection measures against decay in the field or in construction wood.El crecimiento lento y la escasez de especies nativas en Centro América, ha incrementado el uso de algunas especies exóticas, como teca y melina en las últimas décadas, dado su rápido crecimiento y la buena calidad de sus maderas. Un aspecto importante que no ha sido bien estudiado, es la vulnerabilidad de estas maderas, en especial la de teca, al ataque de hongos causantes de podredumbre de la madera utilizada en construcción. Varias especies del género Rigidoporus han sido comunicadas como causantes de podredumbre blanca en angiospermas y gimnospermas a nivel mundial. En Costa Rica, Rigidoporus microporus ha sido reportada en tocones y troncos caídos de teca en plantaciones, pero no se han realizado estudios a nivel de laboratorio sobre los efectos que puede causar en las diferentes propiedades de la madera. Esta investigación se llevó a cabo para determinar los cambios que este hongo puede causar en las propiedades anatómicas, físicas, mecánicas y químicas de la madera de teca. Para determinar si existían diferencias en la severidad del ataque con respecto al estado de desarrollo del árbol, se utilizaron muestras de maderas provenientes de árboles con diferentes edades (albura y duramen de árboles de 6 y 10 años). Se montaron 262 cámaras de podredumbre para realizar las diferentes pruebas, y muestras de madera se removieron cada mes durante 6 meses para estudiar los cambios en las diferentes propiedades a través del tiempo. Los cambios más severos en la anatomía, y las pérdidas de peso y de resistencia más altas fueron obtenidos en las muestras de albura de 6 años. Se observó un aumento en la cantidad de materiales solubles en 1% NaOH y en los contenidos de lignina en todas las muestras analizadas a partir del tercer mes y hasta el final de la prueba. La reducción en pérdida de masa y el aumento de la resistencia de la madera a la fuerza paralela de comprensión al grano, estuvieron relacionadas tanto al tipo de madera como a la edad del árbol de donde esta procedía. Se considera que el conocimiento de los daños potenciales que puede causar este hongo, puede ayudar a realizar una mejor selección de la madera y a desarrollar medidas de protección más efectivas en el campo o a nivel de construcción
    • …
    corecore