Calculating Valid Domains for BDD-Based Interactive Configuration

In these notes we formally describe the functionality of Calculating Valid Domains from the BDD representing the solution space of valid configurations. The formalization is largely based on the CLab configuration framework

The Relationships between Socio-demographic Variables, Travel Motivations and Subsequent Choice of Vacation

Abstract This study explores the relationship between socio-demographic variables and travel motivation and further investigates how travel motivations influence the travelers' choice of vacation. The data were obtained using an internet-based questionnaire administered to a random sample of 256 respondents. Using factor analyses, six motivational factors, thematically similar to other studies on travel motivation, were identified. In contrast to previous research on travel motivations among travelers from other countries, this study identified 'social relationship with family/friends' as the most important motivational factor for Danish travelers. The results show that travel motivations differ across various socio-demographic variables and that travel motivations are related to the travelers' choice of vacation. The article closes with a discussion of the implications of these findings and suggestions for future research

The Giant Snipe (Gallinago undulata) in Argentina

Los registros de la Becasina Gigante (Gallinago undulata) en Argentina datan desde 1886 hasta la actualidad, pero ninguno pudo ser asignado fehacientemente a la especie o bien no hay seguridad de que los especímenes hayan sido colectados dentro del territorio argentino. En consecuencia, los datos son confusos y están sujetos a la interpretación de los especialistas. En este trabajo se resumen los registros de Gallinago undulata en Argentina y se brinda evidencia documentada de su presencia en la región del río Aguapey, departamento de Santo Tomé, provincia de Corrientes, a través de grabaciones de sus vocalizaciones. Se especula sobre el estatus histórico y actual de la especie en Argentina y se recomienda realizar un seguimiento estacional en el área de Aguapey y una búsqueda en los alrededores para determinar su estatus y posibles amenazas a nivel local.Records of the Giant Snipe (Gallinago undulata) in Argentina date from 1886 to the present but none of them could be assigned to this species with certainty and it is not known if some specimens were really collected within Argentina. Therefore, data are confuse and subjective according to the interpretation of specialists. In this study we summarize the available records of Gallinago undulata in Argentina and confirm with recordings its presence in the area of the Aguapey River, Santo Tomé Department, Corrientes Province. We speculate on the historic and present status of the species in Argentina and recommend a seasonal monitoring in Aguapey and further searches in order to determine its status and potential local threats

A Numerical Model of an Acoustic Metamaterial Using the Boundary Element Method Including Viscous and Thermal Losses

[EN] In recent years, boundary element method (BEM) and finite element method (FEM) implementations of acoustics in fluids with viscous and thermal losses have been developed. They are based on the linearized Navier¿Stokes equations with no flow. In this paper, such models with acoustic losses are applied to an acoustic metamaterial. Metamaterials are structures formed by smaller, usually periodic, units showing remarkable physical properties when observed as a whole. Acoustic losses are relevant in metamaterials in the millimeter scale. In addition, their geometry is intricate and challenging for numerical implementation. The results are compared with existing measurements.The authors wish to thank Mads J. Herring Jensen, from the company COMSOL, for his support in setting up the FEM model of the metamaterial. J. Sanchez-Dehesa acknowledges the support by the Spanish Ministerio de Economia y Competitividad, and the European Union Fondo Europeo de Desarrollo Regional (FEDER) through Project No. TEC2014-53088-C3-1-R.Cutanda-Henriquez, V.; Andersen, PR.; Jensen, JS.; Juhl, PM.; Sánchez-Dehesa Moreno-Cid, J. (2017). A Numerical Model of an Acoustic Metamaterial Using the Boundary Element Method Including Viscous and Thermal Losses. Journal of Computational Acoustics. 25(4):1750006-1-1750006-11. doi:10.1142/S0218396X17500060S1750006-11750006-11254Craster, R. V., & Guenneau, S. (Eds.). (2013). Acoustic Metamaterials. Springer Series in Materials Science. doi:10.1007/978-94-007-4813-2Cummer, S. A., Christensen, J., & Alù, A. (2016). Controlling sound with acoustic metamaterials. Nature Reviews Materials, 1(3). doi:10.1038/natrevmats.2016.1Cutanda-Henríquez, V., & Juhl, P. M. (2013). An axisymmetric boundary element formulation of sound wave propagation in fluids including viscous and thermal losses. The Journal of the Acoustical Society of America, 134(5), 3409-3418. doi:10.1121/1.4823840Bruneau, M., Herzog, P., Kergomard, J., & Polack, J. D. (1989). General formulation of the dispersion equation in bounded visco-thermal fluid, and application to some simple geometries. Wave Motion, 11(5), 441-451. doi:10.1016/0165-2125(89)90018-8Kampinga, W. R., Wijnant, Y. H., & de Boer, A. (2010). Performance of Several Viscothermal Acoustic Finite Elements. Acta Acustica united with Acustica, 96(1), 115-124. doi:10.3813/aaa.918262Kampinga, W. R., Wijnant, Y. H., & de Boer, A. (2011). An Efficient Finite Element Model for Viscothermal Acoustics. Acta Acustica united with Acustica, 97(4), 618-631. doi:10.3813/aaa.918442BELTMAN, W. M. (1999). VISCOTHERMAL WAVE PROPAGATION INCLUDING ACOUSTO-ELASTIC INTERACTION, PART I: THEORY. Journal of Sound and Vibration, 227(3), 555-586. doi:10.1006/jsvi.1999.2355Graciá-Salgado, R., García-Chocano, V. M., Torrent, D., & Sánchez-Dehesa, J. (2013). Negative mass density andρ-near-zero quasi-two-dimensional metamaterials: Design and applications. Physical Review B, 88(22). doi:10.1103/physrevb.88.224305Homentcovschi, D., & Miles, R. N. (2011). An analytical-numerical method for determining the mechanical response of a condenser microphone. The Journal of the Acoustical Society of America, 130(6), 3698-3705. doi:10.1121/1.3652853Geuzaine, C., & Remacle, J.-F. (2009). Gmsh: A 3-D finite element mesh generator with built-in pre- and post-processing facilities. International Journal for Numerical Methods in Engineering, 79(11), 1309-1331. doi:10.1002/nme.257

GRB 000301C: a possible short/intermediate duration burst connected to a DLA system

We discuss two main aspects of the GRB 000301C afterglow (Fynbo et al. 2000, Jensen et al. 2000); its short duration and its possible connection with a Damped Ly-alpha Absorber (DLA). GRB 000301C falls in the short class of bursts, though it is consistent with belonging to the proposed intermediate class or the extreme short end of the distribution of long-duration GRBs. Based on two VLT spectra we estimate the HI column density to be Log(N(HI))=21.2+/-0.5. This is the first direct indication of a connection between GRB host galaxies and Damped Ly-alpha Absorbers.Comment: 3 pages, 3 postscript figures. To appear in the proceedings of the October 2000 Rome Workshop on ``Gamma-Ray Bursts in the Afterglow Era'

Multi-Wavelength Studies of the Optically Dark Gamma-Ray Burst 001025A

We identify the fading X-ray afterglow of GRB 001025A from XMM-Newton observations obtained 1.9-2.3 days, 2 years, and 2.5 years after the burst. The non-detection of an optical counterpart to an upper limit of R=25.5, 1.20 days after the burst, makes GRB 001025A a ``dark'' burst. Based on the X-ray afterglow spectral properties of GRB 001025A, we argue that some bursts appear optically dark because their afterglow is faint and their cooling frequency is close to the X-ray band. This interpretation is applicable to several of the few other dark bursts where the X-ray spectral index has been measured. The X-ray afterglow flux of GRB 001025A is an order of magnitude lower than for typical long-duration gamma-ray bursts. The spectrum of the X-ray afterglow can be fitted with an absorbed synchrotron emission model, an absorbed thermal plasma model, or a combination thereof. For the latter, an extrapolation to optical wavelengths can be reconciled with the R-band upper limit on the afterglow, without invoking any optical circumburst absorption, provided the cooling frequency is close to the X-ray band. Alternatively, if the X-ray afterglow is due to synchrotron emission only, seven magnitudes of extinction in the observed R-band is required to meet the R-band upper limit, making GRB 001025A much more obscured than bursts with detected optical afterglows. Based on the column density of X-ray absorbing circumburst matter, an SMC gas-to-dust ratio is insufficient to produce this amount of extinction. The X-ray tail of the prompt emission enters a steep temporal decay excluding that the tail of the prompt emission is the onset of the afterglow (abridged).Comment: 32 pages, 8 figures, ApJ in pres