Influence of loudspeaker directivity on the measurement uncertainty

One of the most significant aspects of a building’s acoustic behavior is the airborne sound insulation of the room façades, since this determines the protection of its inhabitants against environmental noise. For this reason, authorities in most countries have established in their acoustic regulations for buildings the minimum value of sound insulation that must be respected for façades. In order to verify compliance with legal requirements it is usual to perform acoustic measurements in the finished buildings and then compare the measurement results with the established limits. Since there is always a certain measurement uncertainty, this uncertainty must be calculated and taken into account in order to ensure compliance with specifications. The most commonly used method for measuring sound insulation on façades is the so-called Global Loudspeaker Method, specified in ISO 140-5:1998. This method uses a loudspeaker placed outside the building as a sound source. The loudspeaker directivity has a significant influence on the measurement results, and these results may change noticeably by choosing different loudspeakers, even though they all fulfill the directivity requirements of ISO 140-5. This work analyzes the influence of the loudspeaker directivity on the results of façade sound insulation measurement, and determines its contribution to measurement uncertainty. The theoretical analysis is experimentally validated by means of an intermediate precision test according to ISO 5725-3:1994, which compares the values of sound insulation obtained for a façade using various loudspeakers with different directivitie

Nesting Ecology of Polistes Species (hymenoptera, Vespidae) in Urban Areas of South-western Iberian Peninsula

Urbanization is increasing across the globe and it is recognized as a major factor affectingspecies, populations and assemblages. Although urbanization is recognized as a major threat to biodiversity, there is increasing evidence that urban habitats may play a role in conservation. The objective of this work was to verify the occurrence of Polistes species (Vespidae) and the substrates used for nesting in urban areas in south-western Iberian Peninsula. The study was carried out from March to August of 2018 in three small towns in the Llanos de Olivenza region (SW Spain). Active searching was conducted for colonies of social wasps along and for each colony that was found we identified the species, type of substrate used for nesting, height of the colony in relation to the ground level and orientation. 753 colonies of social wasps were found belonging to two species: Polistes dominula and P. gallicus.  The most used nesting substrate was clay roof tile followed by metals. The height of the nests was related to the height of the buildings on which they were built. In all the tree towns nests exposure were oriented to the SE with mean angle values oscillating between 127.42° and 140.68°. In addition, our results confirm the prediction that wasps are more abundant in less or non-urbanized areas even if they are small urban areas such as those studied in our case

Causas de mortalidad de colonias de Polistes dominula (Christ, 1791) (Hymenoptera, Vespidae) en zonas urbanas del suroeste de la Península Ibérica

From 2017 to 2018 we studied populations of the eusocial paper wasp Polistes dominula (Christ, 1791) in three municipalities of the south-western Iberian Peninsula, in order to identify the causes of colony mortality. The results showed that the first main cause of mortality in the study area was human activity (43.55 %). The second most important cause was abandonment of the nest (20.19 %). Only 82 of the 411 nests (19.95 %) showed signs of natural colony decline, following the emergence of reproductives.De 2017 a 2018 se estudiaron diversas poblaciones de la avispa eusocial Polistes dominula (Christ, 1791) en tres municipios del suroeste de la península ibérica, con la finalidad de identificar las causas de mortalidad de sus colonias. Los resultados mostraron que la causa principal de mortalidad en las zonas de estudio fue la actividad antrópica (43,55 %). La segunda causa más relevante fue el abandono del nido (20,19 %). Únicamente 82 de 411 nidos (19,95 %) demostraron un declive natural de la colonia, tras la aparición de reproductores

An approach to build in situ models for the prediction of the decrease of academic engagement indicators in Massive Open Online Courses

Producción CientíficaThe early detection of learners who are expected to disengage with typical MOOC tasks such as watching lecture videos or submitting assignments is necessary to enable timely interventions aimed at preventing it. This can be done by predicting the decrease of academic engagement indicators that can be derived for di_erent MOOC tasks and computed for each learner. A posteriori prediction models can yield a good performance but cannot be built using the information that is available in an ongoing course at the moment the predictions are required. This paper proposes an approach to build in situ prediction models using such information. Models were derived following both approaches and employed to predict the decrease of three indicators that quantify the engagement of learners with the main tasks typically proposed in a MOOC: watching lectures, solving _nger exercises, and submitting assignments. The results show that in situ models yielded a good performance for the prediction of all engagement indicators, thus showing the feasibility of the proposed approach. This performance was very similar to that of a posteriori models, which have the clear disadvantage that they cannot be used to make predictions in an ongoing course based on its data.Ministerio de Economía, Industria y Competitividad (Projects TIN2014-53199-C3-2-R (AEI, FEDER), TIN2017-85179-C3-2-R)Junta de Castilla y León (programa de apoyo a proyectos de investigación - Ref. VA277U14)European Commission (Proyect 588438-EPP-1-2017-1-EL-EPPKA2-KA

Recreational fisheries in rural regions of the South-Western Iberian peninsula: a case study

La dimensión humana de la pesca deportiva ha ganado interés en todo el mundo durante la última década para la correcta gestión de los recursos naturales. Sin embargo, en muchas regiones rurales del sur de Europa, los aspectos sociales y económicamente de la pesca deportiva siguen siendo poco estudiados. En este estudio se realizó una encuesta para cubrir esta brecha de conocimientos y elaborar recomendaciones de manejo potenciales para la explotación adecuada. Una encuesta de la pesca recreativa se llevó a cabo durante la temporada de pesca 2008-2009. Los datos se recogieron siguiendo los procedimientos de la encuesta de nasas y las respuestas a 171 entrevistas fueron analizadas para 27 variables. Para asociar estas variables categóricas se realizó un análisis de componentes principales (CATPCA). En el eje CATPCA en primer lugar (44,24% de la varianza), las correlaciones entre las variables mostraron una dimensión "económica". Las variables más influyentes en esta dimensión fueron los gastos, la temporada y el número de días de pesca por año, junto con la distancia recorrida a los sitios de pesca. La segunda dimensión (24,47% de la varianza) estaba relacionada con las especies preferidas, el equipo necesario para la captura de ellos, y con la facilidad de acceso a los sitios donde se encuentran estas especies. Los datos mostraron algunas diferencias entre los pescadores jóvenes y mayores con respecto a las variables analizadas.The human dimension of recreational fishing has gained interest worldwide during the last decade for proper management of the natural resources. However, in many rural regions in Southern Europe, the social and economically aspects of recreational fishing remains poorly studied. In this study we conducted a survey to cover this gap of knowledge and draw potential management recommendations for proper exploitation. A survey of recreational fishing was conducted during the 2008-2009 fishing seasons. Data were collected following creel survey procedures and responses to 171 interviews were analyzed for 27 variables. To associate these variables a categorical principal components analysis (CATPCA) was performed. On the first CATPCA axis (44.24% of variance), the correlations among variables showed an “economic” dimension. The most influential variables in this dimension were expenditure, the season, and number of fishing days per year, together with the distance travelled to fishing sites. The second dimension (24.47% of variance) was related to the preferred species, the gear necessary to catch them, and with facility off access to sites where these species are found. The data showed some differences between both young and old fishermen with respect to the variables analyzed.-- Junta de Extremadura. Servicio de Medio AmbientepeerReviewe

Procedimiento para la medición y verificación de la directividad y la cobertura de una fuente sobre un elemento de fachada de acuerdo a la norma ISO 140-5

El apartado de la Norma Internacional UNE-EN ISO 140-5 [1] especifica que la directividad del altavoz usado en el ensayo debe asegurar en todas las bandas de frecuencias de interés, unas diferencias de nivel locales inferiores a 5dB (o a 10 dB para fachadas de dimensiones mayores a 5m), medidas en campo libre, sobre una superficie del mismo tamaño y orientación que la pared o elemento a ensayar. Este requisito debe verificarse en unas bandas de frecuencia de interés que sean como mínimo los tercios de octava desde 100Hz hasta 3150Hz, y preferiblemente desde 50Hz hasta 5kHz. Desde hace unos años, en el Laboratorio de sonido de la EUIT de Telecomunicación de la Universidad Politécnica de Madrid, los autores han implementado un método en el que, a partir de las medidas de directividad en cámara anecoica de la fuente sonora a ensayar, se calcula el campo sonoro directo sobre una superficie ficticia que representa un elemento de fachada en la misma disposición que se indica en la norma ICO 140-5 y con unas dimensiones según se requieran en el procedimiento. También se estima la dimensión horizontal máxima ΔXmax de una fachada rectangular en relación de aspecto fija que permite verificar la norma con los criterios de 5dB y 10dB de diferencias máximas de niveles directos en dicha fachada. En esta ponencia se detalla el procedimiento anterior. ABSTRACT. The Section "4.2 loudspeaker" of the UNE-EN ISO 140-5 International Standard: "Field measurements of airborne sound insulation of façade elements and façades", specifies that the directivity of the loudspeaker used in the test must ensure in all frequency bands of interest, local level differences less than 5dB (or 10dB for façade dimensions greater than 5m), measured in free field over an area of the same size and orientation as the wall or element to be tested. This requirement must be verified in the frequency bands of interest which are, at least, the third octave bands from 100Hz to 3150Hz, preferably from 50Hz to 5kHz. In recent years, in the Laboratory of Sound of the EUIT Telecomunicación (Universidad Politécnica de Madrid), the authors have implemented a method that, from directivity measurements of loudspeakers performed in the anechoic room, the direct sound field on a surface in the same layout as indicated in the ISO standard is calculated. It is also estimated the maximum horizontal dimension Δxmax of a rectangular façade for each aspect ratio which verify the standard criteria of either 5dB or 10dB for the maximum differences of direct levels in the façade. This paper details the procedure above introduced

Primera cita de Neoscona byzanthina (Pavesi, 1876) (Araneae, Araneidae) en la Península Ibérica

Neoscona byzanthina (Pavesi, 1786) (Araneae, Araneidae) is reported for the first time in the Iberian Peninsula. The specimen was captured on October 2018 in a holm-oak dehesa (Extremadura, Spain).Se hace referencia a la primera observación de Neoscona byzanthina (Pavesi, 1876) (Araneae, Araneidae) de la Península Ibérica. El ejemplar fue capturado en octubre de 2018 en un encinar adehesado (Extremadura, España)

Nest Association between Camponotus fallax (Hymenoptera: Formicidae) and Vespa crabro (Hymenoptera: Vespidae) in Central Iberian Peninsula

Because social wasps often defend their nests by inflicting painful stings or bites, some animals associate with them looking for protection against potential predators. Some neotropical vespids are known to maintain associations with other insect and vertebrate taxa, such as birds and bats, however there are not previous records about associations between ants and hornets in Europe. In this study, we reported the first case of association between the arboreal ant Camponotus fallax and the European hornet Vespa crabro in Europe. The observations were made in Central Spain, where two colonies of C. fallax were found in two different avian nest-boxes inhabited by V. crabro when spotless starlings finished their breeding season. The reasons of this possible association are also discussed

Introducción a la Estadística Circular

La Estadística Circular se ocupa del análisis de datos circulares, unos datos con unas características muy particulares. En primer lugar, la escala en la que se desenvuelven es finita, ya que tiene una amplitud de 0° a 360°. En segundo lugar, la posición del cero es arbitraria, ya que no existe argumento científico para no poder situarlo en cualquier punto del círculo. En tercer lugar, no existen magnitudes cuando tratamos con datos circulares, ya que 270° no son más que 180°, sino que señalan direcciones diferentes. Estas (y algunas más) hacen que los procedimientos utilizados en estadística lineal no sean aplicables a los datos circulares, por ello nace la Estadística Circular, para que se puedan tratar este tipo de datos. La mayoría de los datos circulares se obtienen en forma de direcciones u orientaciones, pero también son datos circulares fenómenos cíclicos, es decir, aquellos que pueden acontecer en una hora, un día, una semana o un año. Dada la versatilidad de los datos circulares son muchas las disciplinas en las que se utilizan datos circulares, quizás en la que más se utilicen sea en Biología o, por ser más exactos, en las diferentes ramas de la Biología: Botánica, Etología, Fisiología, Geología, Biología Molecular, etc., pero también son empleados en Medicina, Meteorología, Ciencias de la Computación, Sociología, Ciencias Políticas, etc. Se ha optado por incluir ejercicios resueltos, de modo que el lector pueda realizarlos con la ayuda de una calculadora o una hoja de cálculo, evitando el empleo de programas informáticos (que existen para tal fin). Este trabajo ha sido dividido en cinco capítulos. El primero es un capítulo introductorio donde se explica que es la Estadística Circular, sus orígenes e historia, para finalizar con una breve reseña sobre las principales obras publicadas sobre el tema, los principales programas informáticos que se pueden utilizar y una serie de ejemplos obtenidos de la bibliografía, que permitirán evaluar la importancia y aplicabilidad de esta disciplina. En capítulo dos está dedicado a los datos empleados en estadística circular, aspecto sumamente importante ya que, aunque parezca lo contrario, son numerosas las formas de poder expresar datos circulares. El tercer capítulo está dedicado a la estadística descriptiva, a las representaciones gráficas y a las distribuciones circulares. El capítulo cuarto está dedicado a la inferencia estadística, básicamente a los test de uniformidad y a los test de bondad del ajuste. En el capítulo cinco se aborda otro aspecto interesante de las relaciones entre variables circulares y lineales: la correlación circula-circular y circular-lineal. Se ha incluido un anexo con las tablas de los valores críticos de los test estadísticos utilizados en el libro.The Circular Statistics deals with the analysis of circular data, data with very particular characteristics. Firstly, the scale on which they are developed is finite, as it has an amplitude of 0° to 360°. Secondly, the position of the zero is arbitrary, since there is no scientific argument for not being able to locate it at any point of the circle. Thirdly, there are no magnitudes when dealing with circular data, as 270° is only 180°, but points in different directions. These (and some others) make the procedures used in linear statistics not applicable to circular data, so the Circular Statistics is born, so that this type of data can be treated. Most circular data are obtained in the form of directions or orientations, but circular data are also cyclical phenomena, that is, those that can occur in an hour, a day, a week or a year. Given the versatility of circular data, there are many disciplines in which circular data are used, perhaps the most widely used is in Biology or, to be more exact, in the different branches of Biology: Botany, Ethology, Physiology, Geology, Molecular Biology, etc., but they are also used in Medicine, Meteorology, Computer Science, Sociology, Political Science, etc. It has been decided to include solved exercises, so that the reader can perform them with the help of a calculator or a spreadsheet, avoiding the use of computer programs (which exist for this purpose). This work has been divided into five chapters. The first is an introductory chapter explaining what Circular Statistics is, its origins and history, and ends with a brief review of the main works published on the subject, the main computer programs that can be used and a series of examples obtained from the bibliography, which will allow the importance and applicability of this discipline to be evaluated. Chapter two is devoted to data used in circular statistics, an extremely important aspect since, although it may seem otherwise, there are many ways of expressing circular data. The third chapter is dedicated to descriptive statistics, graphic representations and circular distributions. The fourth chapter is dedicated to statistical inference, basically the uniformity test and the goodness of fit test. Chapter five deals with another interesting aspect of the relationships between circular and linear variables: the circular-circular and circular-linear correlation. An appendix has been included with the tables of the critical values of the statistical tests used in the book

Ejercicios resueltos de gestión cinegética

Se presentan aquí una serie de ejercicios relacionados con la asignatura Ordenación Cinegética y Piscícola. La gestión cinegética incluye una gran variedad de aspectos que pueden abordar desde la gestión económica de un coto, hasta la estima de parámetros biológicos o ecológicos de las especies cinegéticas. Obviamente no se encontrarán problemas sobre todos ellos, pero sí sobre los que con más frecuencia aparecen cuando se hace un proyecto de gestión, tales como estimas poblacionales o el cálculo de los cupos de captura. Algunos de los problemas que apareen en esta relación son propios, pero otros están basados o se han tomado de otros autores. Muchos de los dibujos NO están a escala, ya que solo se ha pretendido realizar una representación gráfica de una situación real para que la comprensión del problema sea más sencilla