Browsing by Subject "Seasonality"
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- PublicationOpen AccessComparative study of immunological biomarkers in the carpet shell clams (Ruditapes decussatus) from metal‑contaminated sites in the South Lagoon of Tunis (Tunisia)(Springer, 2022-09-14) Mansour, Chalbia; Esteban Abad, María de los Ángeles; Rouane Hacene, Omar; Saidane Mosbahi, Dalila; Guardiola Abellán, Francisco Antonio; Biología Celular e Histología; Facultad de BiologíaThe South Lagoon of Tunis (Tunisia) is a Mediterranean lagoon adversely affected by industrial contaminants, harbour activity and untreated urban sewage. In this lagoon, the clam Ruditapes decussatus has been widely used as a biomonitor of seawater pollution through measurements of parameters related to oxidative stress and neurotoxicity. However, few studies have considered parameters of the immune system of this species in the South Lagoon of Tunis. Therefore, the aim of the present work was to evaluate several immune-related parameters in the cell-free haemolymph of carpet shell clams sampled during August and February from three polluted sites in the South Lagoon of Tunis (S1, S2 and S3) and one less polluted site as a reference site (RS) in order to identify suitable biomarkers for environmental quality assessments of this ecosystem. Concerning the immune-related parameters, seasonal factors modulated phenoloxidase, lysozyme, protease and esterase activity, with lower values measured for samples collected in August than for samples collected in February. In fact, bactericidal activity against two of the pathogenic bacteria tested and the activity of most immune-related enzymes were reduced in the cell-free haemolymph of clams collected from the most sampling sites in August compared to February one. In addition, values of abiotic parameters (temperature, salinity and pH) and metal (cadmium, copper, iron, lead and zinc) concentrations in the clams’ soft tissues, previously obtained and published by the authors, as well as the values of immune-related parameters were integrated using principal component analyses. Results indicated that the values of all measured immune-related parameters were negatively correlated with the temperature values and the variations most of these parameters highlighted that the chemical industrial area (S3) was the most impacted location within the South Lagoon of Tunis. The present study illustrates that the immune-related parameters measured in carpet shell clam cell-free haemolymph represent suitable biomarkers for environmental quality assessments because they provide effective seasonal and spatial discrimination.
- PublicationOpen AccessEL CONSUMO DE AGUA POTABLE EN LOS MUNICIPIOS TURÍSTICOS DEL LITORAL DE LA REGIÓN DE MURCIA(Universidad de Murcia. Servicio de publicaciones, 2022) Bernabé Crespo, Miguel Borja; Gil Meseguer, Encarnación; Gómez Espín, José MaríaLa Región de Murcia es un área de clima mediterráneo semiárido con escasez de recur-sos hídricos. Dotar a su litoral turístico de unos caudales seguros, especialmente en verano, momento de mayor afluencia que coincide con la sequía estival, es una tarea que condiciona y sustenta el desarrollo económico de la Región. El objetivo de este artículo es analizar el consumo de agua potable en los municipios del litoral de la Región de Murcia en el periodo 2016-2020, mediante un estudio cualitativo y cuantitativo. Se destacan las diferencias en cuanto a rendimiento, consumo per cápita y estacionalidad
- PublicationOpen AccessLa diversificación de la oferta turística como alternativa para minimizar la estacionalidad: el caso de los eventos en Balneário Camboriú (Santa Catarina, Brasil)(Universidad de Murcia, 2017) Calçada de Lamare Leite, FabianaEl artículo analiza la diversificación de la oferta turística con la realización de eventos cómo una alternativa para reducir la estacionalidad. La ciudad de estudio es Balneário Camboriú, en el estado de Santa Catarina, Brasil. El enfoque de la investigación es bibliográfico. El marco teórico aborda el concepto de estacionalidad y el caso del Balneário Camboriú a partir de un enfoque histórico de la estructuración de la actividad turística en la ciudad y la identificación de los eventos como alternativa de diversificación de la oferta turística.
- PublicationOpen AccessEffects of water salinity on melatonin levels in plasma and peripheral tissues and on melatonin binding sites in European sea bass (Dicentrarchus labrax)(Elsevier, 2009) López Olmeda, José Fernando; Oliveira, Catarina; Kalamarz, Hanna; Kulczykowska, Ewa; Delgado, María Jesús; Sánchez Vázquez, Francisco Javier; FisiologíaSea bass is a euryhaline fish that lives in a wide range of salinities and migrates seasonally from lagoons to the open sea. However, to date, the influence of water salinity on sea bass melatonin levels has not been reported. Here, we evaluated the differences in plasma and tissue melatonin contents and melatonin binding sites in sea bass under four different salinities: seawater (36 ‰), isotonic water (15 ‰), brackish (4 ‰) and freshwater (0 ‰). Melatonin content was evaluated in plasma, whole brain, gills, intestine and kidney, while melatonin binding sites were analyzed in different brain regions and in the neural retina. Plasma melatonin levels at mid-dark varied among salinities, with the lowest value occurring at seawater salinity (102 pg/ml), and the highest at freshwater (151 pg/ml). In gills and intestine, however, the highest melatonin values were found in the seawater group (209 and 627 pg/g tissue, respectively). Melatonin binding sites in the brain also varied with salinity, with the highest density being observed at the lower salinities in optic tectum, cerebellum and hypothalamus (30.3, 13.0, and 8.0 fmol/mg protein, respectively). Melatonin binding sites in the retina showed a similar pattern, with the highest values in the fish maintained in freshwater. Taken together, these results revealed that salinity influences melatonin production and modifies the density of binding sites, which would point to a role for this hormone in timing seasonal events in sea bass, including those linked to fish migration between waters of different salinities.
- PublicationOpen AccessEstacionalidad turística en las provincias españolas: medición y análisis(Murcia: Servicio de Publicaciones de la Universidad de Murcia, 2015) Duro Moreno, Juan Antonio; Farré, Francesc XavierEn este trabajo se lleva a cabo un análisis de la concentración temporal de la demanda turística en las provincias españolas para el período 1999-2012. El análisis se realiza a partir del uso de diferentes índices sumario, que recogen diferentes sensibilidades de las medidas en relación a la distribución temporal de la actividad, y de los datos de pernoctaciones hoteleras ofrecidos por el INE. El trabajo realiza un análisis descriptivo de la concentración provincial, de su evolución temporal y, finalmente aborda el grado de correlación entre la concentración y diferentes vectores explicativos potenciales.
- PublicationOpen AccessFlexibilidad laboral en el mercado de trabajo español(Murcia : Universidad de Murcia, 2013) Ortiz García, PilarEste artículo aborda uno de los procesos que ha acompañado a la transformación del modelo de regulación económica del capitalismo desde la norma social de empleo estable, hasta lo que sociológicamente ha sido calificado como “anomia posfordista”, término utilizado para hacer referencia a los procesos de reestructuración flexible del trabajo y, con él, de las relaciones laborales. Nos referimos a la flexibilidad laboral y, en concreto, a la temporalidad en el empleo. A partir de la revisión teórica sobre el tema, este trabajo continúa indagando en la morfología de la temporalidad, su origen, evolución y consecuencias, el perfil del trabajador flexible y la política laboral que, a partir de las últimas reformas, conforma un mercado de trabajo en el que el empleo “atípico” es una de las señas de identidad. La normativa más significativa en este aspecto, así como los datos de facilitados por la Encuesta de Población Activa sirven como elementos para el análisis de un mercado laboral que -según las conclusiones del estudio-, corre el riesgo de convertir en estructural una debilidad coyuntural de sus efectivos.
- PublicationOpen AccessMonth of birth and height. A case study in rural Spain(Elsevier, 2022-07-06) Candela Martínez, Begoña; Ramallo-Ros, Salvador; Cañabate, José; Martínez Carrión, José Miguel; Economía Aplicada; Facultad de Economía y EmpresaIntroduction: Season of birth correlates to a wide range of health conditions throughout life measured by anthropometrics. This study explores whether the month of birth and weather during gestation influence male adult height, based on Spain’s rural population before the end of the modernization process. Methods: The database of heights (N = 16.266) is composed of conscripts who reached the age of 21 between 1908 and 1985 (birth cohorts 1886–1965). The population sample has been taken from a municipality in inner Spain: Hellín, in the region of Castilla-La Mancha, mainly an agrarian area, with poor resources and low income until the 1970 s/1980 s. Two different methodologies have been implemented: a harmonic regression using sinusoidal covariables and a random forest model. Results: we find that being born at the end of the summer and during the autumn was favorable to height. The birth month with the highest statures is September, with heights 0.5 cm above the annual average and 0.9 cm above February, the birth month with the lowest average height. Furthermore, we can observe that rainfall and temperature during gestation had little additional influence due to a substitution effect with the birth month variable. Conclusions: Our results suggest that the seasonal effects on height can be significant and that it can be partially affected by environmental factors during early life. Our findings could be of interest for low-income populations and developing rural societies.
- PublicationOpen AccessPeriod of Boar Ejaculate Collection Contributes to the Yearly Intra-Male Variability of Seminal Plasma Cytokines(MDPI, 2020-05-20) Padilla, Lorena; Lucas, Xiomara; Parrilla, Inmaculada; Pérez-Patiño, Cristina; Rodríguez-Martínez, Heriberto; Roca, Jordi; Barranco, Isabel; Medicina y Cirugía AnimalThe concentrations of cytokines in seminal plasma (SP) fluctuate over time in healthy males, weakening their practical usefulness as diagnostic tools. This study evaluated the relevance of intra-male variability in SP cytokines and to what extent the period of the year when ejaculate is collected contributes to such variability. Thirteen cytokines (GM-CSF, IFNγ, IL-1α, IL-1β, IL-1ra, IL-2, IL-4, IL-6, IL-8, IL-10, IL-12, IL-18, and TNFα) were measured using the Luminex xMAP® technology for 180 SP samples of ejaculate collected over a year from nine healthy and fertile boars. The SP samples were grouped into two annual periods according to decreasing or increasing daylight and ambient temperature. Intra-male variability was higher than inter-male variability for all cytokines. All SP cytokines showed concentration differences between the two periods of the year, showing the highest concentration during the increasing daylength/temperature period, irrespective of the male. Similarly, some cytokines showed differences between daylength/temperature periods when focusing on their total amount in the ejaculate. No strong relationship (explaining more than 50% of the total variance) was found between annual fluctuations in SP-cytokine levels and semen parameters. In conclusion, the period of the year during which ejaculates were collected helps explain the intra-male variability of SP-cytokine levels in breeding boars.
- PublicationRestrictedSeason of ejaculate collection influences the freezability of boar spermatozoa(Elsevier, 2013-12-03) Barranco Cascales, Isabel; Ortega, María D.; Martínez Alborcia, María J.; Vázquez, Juan M.; Martínez García, Emilio; Roca Aleu, Jorge; Medicina y Cirugía AnimalThe aim of this retrospective study was to evaluate whether the season of ejaculate collection influences the freezability of porcine sperm. A total of 434 ejaculates were collected from boars of six different breeds over three years (2008-2011) and throughout the four seasons of the year identified in the northern hemisphere (winter, spring, summer and autumn). The ejaculates were cryopreserved using a standard 0.5 mL straw freezing protocol. Sperm quality was assessed before (fresh semen samples kept 24h at 17°C) and after freezing and thawing (at 30 and 150 min post-thawing in semen samples kept in a water bath at 37 °C), according to the percentages of total motility, as assessed by the CASA system, and viability, as assessed by flow cytometry after staining with SYBR-14, PI and PE-PNA. The data, in percentages, on sperm motility and viability after freezing and thawing were obtained at each evaluation time (recovered) and were normalized to the values before freezing (normalized). The season of ejaculate collection influenced (P<0.01) sperm quality before freezing and after thawing (recovered and normalized), irrespective of the breed of boar. Sperm quality was lower in summer, both in terms of motility and viability, and in autumn, in terms of motility, than in winter and spring. Seasonality in the normalized data indicates that the season of ejaculate collection influences sperm freezability, regardless of the season's influence on sperm quality before freezing. Consequently, the spermatozoa from ejaculates collected during summer and, to a lesser extent, also in autumn, are more sensitive to cryopreservation than those from ejaculates collected during winter and spring.
- PublicationOpen AccessSeasonality and freezability vs routine parameters in stallion semen(Murcia : F. Hernández, 1996) Rodríguez, H.; Bustos-Obregón, E.The fertilizing ability of stallion semen was analyzed using fresh and frozen samples, obtained before (June-July) or during (October-November) the breeding season. Thirty ejaculates obtained from 4 stallions, were used. The analysis comprises routine seminogram; ATP concentration (Comhaire et al., 1983); subjective and objective motility and sperm velocity (Makler, 1980). Freezing was done following the technique of Martin et al. (1979). Sperm velocity, ATP content and objective motility in ejaculates of subjective motility >50% show values of 14.010.84 ym S-l; 4.8f 2 . 7 1~O - ~ Man d 54.0I7.4%, respectively. For ejaculates with subjective motility ~ 5 0 %the~se values are 8.412.4; 0.74f 0 . 3 6 1~ 0 - 7 a~n d 27.0+0.8%. No significant changes in these characteristics were elicited by freezing, though ATP content dropped to 50% after thawing. These characteristics are highly associated between them (pc0.05) and with some conventional parameters of the routine seminogram such as sperm motility, count, total spermatozoal number and morphology. Additionally, sperm chromatin packing was analyzed by decondensing sperm nuclei using a thiol reducing agent. This parameter was not modified by freezing and it may depend on prolonged epididymal sperm storage during the non-breeding season. Epididymal maturation then results in an excessive disulphur bridging in sperm basic proteins, so that hypermaturation with faultly male pronuclear formation can follow.
- PublicationOpen AccessThe dynamics of the university impact on YouTube: a comparative analysis(2021) Ros Gálvez, Alejandro; Meseguer Martínez, Ángel; López Buenache, Germán; Métodos Cuantitativos para la Economía y la EmpresaThe impact of universities on social networks has been widely studied, especially on Facebook and Twitter. However, there is a clear lack of research on YouTube, despite an overwhelming presence of universities on this online video platform. The objective of this work is to analyse similarities in the dynamics of views and likes between the YouTube channel of a university, Polytechnic University of Valencia (UPV), and an educational channel, the saurabhschool [25]. This is the first work that analyzes the dynamics of online video impact of a university on YouTube, which are subsequently compared to those of an educational channel to find common patterns. The times series of views and likes are obtained for both channels, their seasonal components are calculated and compared. Observation is subsequently supported by an analysis of correlations and the Euclidean distance. Results suggest that the video impact dynamics of a university channel behave similarly to those of an educational channel. These results can help universities anticipate the behavior pattern of their videos in order to maximize the impact of their content through YouTube.