What DNA barcodes reveal : microhabitat preference, hunting strategy and dispersal ability drive genetic variation across Iberian spider species

1. The current rate of species loss calls for immediate actions to preserve biodiversity and ecosystem functioning. Cataloguing species richness and composition, and revealing how diversity is geographically distributed are the first steps towards designing efficient conservation strategies. 2. Here, we aim to determine diversity patterns and potential drivers of taxonomic and genetic diversity and population structure of Iberian spiders. We used a community level perspective, analysing more than 3000 DNA barcode sequences representing similar to 370 spider species dwelling in white-oak forest habitats across the Spanish National Park network. 3. By combining and comparing morphological and DNA barcode-based species delimitation methods, we assessed their performance and identified putative factors behind cases of incongruence. Our findings uncovered potential overlooked diversity as suggested by the geographic patterns of genetic variation and put a red flag on those taxa that may be undergoing overlooked evolutionary or ecological processes. 4. Spider functional traits associated with foraging strategy, microhabitat preference, ballooning ability and circadian activity explained the observed patterns of population structure across species but did not explain variation in genetic diversity. Overall, our study represents a major step forward in the understanding of large-scale diversity patterns in Iberian spiders at the community level and provides relevant information to guide future conservation strategies of the so-far largely overlooked invertebrate diversity.Peer reviewe

Combustion modeling in a pressurized gas turbine burner using Large-Eddy Simulations

The research leading to these results has received funding from the European Union's Horizon 2020 Programme under the ESTiMatE project, grant agreement No. 821418. The authors thankfully acknowledge the computer resources at MareNostrum and the technical support provided by Barcelona Supercomputing Center (IM-2020-3-0022, IM-2021-1-0016).García-Oliver, JM.; Pastor Enguídanos, JM.; Olmeda-Ramiro, I.; Both, A.; Mira, D. (2022). Combustion modeling in a pressurized gas turbine burner using Large-Eddy Simulations. 690-699. http://hdl.handle.net/10251/19067769069

For all audiences : Incorporating immature stages into standardised spider inventories has a major impact on the assessment of biodiversity patterns

Although arthropods are the largest component of animal diversity, they are traditionally underrepresented in biological inventories and monitoring programmes. However, no biodiversity assessment can be considered informative without including them. Arthropod immature stages are often discarded during sorting, despite frequently representing more than half of the collected individuals. To date, little effort has been devoted to characterising the impact of discarding nonadult specimens on our diversity estimates. Here, we used a metabarcoding approach to analyse spiders from oak forests in the Iberian Peninsula, to assess (1) the contribution of juvenile stages to local diversity estimates, and (2) their effect on the diversity patterns (compositional differences) across assemblages. We further investigated the ability of metabarcoding to inform on abundance. We obtained 363 and 331 species as adults and juveniles, respectively. Including the species represented only by juveniles increased the species richness of the whole sampling in 35% with respect to those identified from adults. Differences in composition between assemblages were greatly reduced when immature stages were considered, especially across latitudes, possibly due to phenological differences. Moreover, our results revealed that metabarcoding data are to a certain extent quantitative, but some sort of taxonomic conversion factor may be necessary to provide accurate informative estimates. Although our findings do not question the relevance of the information provided by adult-based inventories, they also reveal that juveniles provide a novel and relevant layer of knowledge that, especially in areas with marked seasonality, may influence our interpretations, providing more accurate information from standardised biological inventories.Peer reviewe

A computational analysis of the impact of bore-to-stroke ratio on emissions and efficiency of a HSDI engine

[EN] Research on combustion systems for Internal Combustion Engines (ICE) is guided by the necessity of improving engine efficiency while achieving the pollutant regulations. In this framework, this study identifies and describes the effect of the bore-to-stroke ratio (B/S) on the combustion system performance and emissions by means of computational fluid dynamics (CFD). The study is applied to a 4-cylinder 4-stroke High Speed Direct Injection (HSDI) CI engine. It is divided in two parts, the first part is focused on one operating point and presents a detailed description of the main effects of different B/S ratios configurations, and the second part compares the results with different engine operating conditions. For both parts the air management, injection settings and compression ratio were kept constant in order to isolate the impact of the B/S ratio. The results confirmed that the indicated thermal efficiency was increased for lower B/S ratio because of the combustion chamber surface area decrease and faster combustion. Regarding the emissions, NOx and soot presented a strong and opposed dependence on B/S ratio generated mostly due to enhanced air¿fuel mixing for lower B/S ratio. Finally, those trends were proven to be independent from the operating condition, giving the study a more general value.Authors acknowledge that this work was possible thanks to the Ayuda para la Formation de Profesorado Universitario (FPU 13/02817) belonging to the Subprogramas de Formacion y de Movilidad del Ministerio de Educacion, Cultura y Deporte from Spain. The authors would also like to recognize the funding and technical support from PSA GroupeBenajes, J.; Novella Rosa, R.; Pastor Enguídanos, JM.; Hernández-López, A.; Duverger, T. (2017). A computational analysis of the impact of bore-to-stroke ratio on emissions and efficiency of a HSDI engine. Applied Energy. 205:903-910. https://doi.org/10.1016/j.apenergy.2017.08.023S90391020

LES Eulerian diffuse-interface modeling of fuel dense sprays near- and far-field

[EN] Engine fuel spray modeling still remains a challenge, especially in the dense near-nozzle region. This region is difficult to experimentally access and also to model due to the complex and rapid liquid and gas interaction. Modeling approaches based on Lagrangian particle tracking have failed in this area, while Eulerian modeling has proven to be particularly useful. Interface resolved methods are still limited to primary atomization academic configurations due to excessive computational requirements. To overcome those limitations, the single-fluid diffuse interface model known as Sigma-Y, arises as a single-framework for spray simulations. Under the assumption of scale separation at high Reynolds and Weber numbers, liquid dispersion is modeled as turbulent mixing of a variable density flow. The concept of surface area density is used for representing liquid structures, regardless of the complexity of the interface. In this work, a LES based implementation of the Sigma-Y model in the OpenFOAM CFD library is applied to simulate the ECN Spray A configuration. Model assessment is performed for both near- and far-field spray development regions using different experimental diagnostics available from ECN database. The CFD model is able to capture near-nozzle fuel mass distribution and, after Sigma equation constant calibration, interfacial surface area. Accurate predictions of spray far-field evolution in terms of liquid and vapor tip penetration and local velocity can be simultaneously achieved. Model accuracy is lower when compared to mixture fraction axial evolution, despite radial distribution profiles are well captured.This work was partially funded by the Spanish Ministerio de Economia y Competitividad within the frame of the CHEST (TRA2017-89139-C2-1-R) project. The computations were partially performed on the Tirant III cluster of the Servei d'Informatica of the University of Valencia (vlc38-FI-2018-2-0006). Authors acknowledge the computer resources at Picasso and the technical support provided by Universidad de Malaga (UMA) (RES-FI-2018-1-0039).Desantes Fernández, JM.; García-Oliver, JM.; Pastor Enguídanos, JM.; Olmeda-Ramiro, I.; Pandal, A.; Naud, B. (2020). LES Eulerian diffuse-interface modeling of fuel dense sprays near- and far-field. International Journal of Multiphase Flow. 127:1-13. https://doi.org/10.1016/j.ijmultiphaseflow.2020.103272S113127Andreini, A., Bianchini, C., Puggelli, S., & Demoulin, F. X. (2016). Development of a turbulent liquid flux model for Eulerian–Eulerian multiphase flow simulations. International Journal of Multiphase Flow, 81, 88-103. doi:10.1016/j.ijmultiphaseflow.2016.02.003Anez, J., Ahmed, A., Hecht, N., Duret, B., Reveillon, J., & Demoulin, F. X. (2019). Eulerian–Lagrangian spray atomization model coupled with interface capturing method for diesel injectors. International Journal of Multiphase Flow, 113, 325-342. doi:10.1016/j.ijmultiphaseflow.2018.10.009Baldwin, E. T., Grover, R. O., Parrish, S. E., Duke, D. J., Matusik, K. E., Powell, C. F., … Schmidt, D. P. (2016). String flash-boiling in gasoline direct injection simulations with transient needle motion. International Journal of Multiphase Flow, 87, 90-101. doi:10.1016/j.ijmultiphaseflow.2016.09.004Bardi, M., Payri, R., Malbec, L. M., Bruneaux, G., Pickett, L. M., Manin, J., … Genzale, C. (2012). ENGINE COMBUSTION NETWORK: COMPARISON OF SPRAY DEVELOPMENT, VAPORIZATION, AND COMBUSTION IN DIFFERENT COMBUSTION VESSELS. Atomization and Sprays, 22(10), 807-842. doi:10.1615/atomizspr.2013005837Battistoni, M., Som, S., & Powell, C. F. (2019). Highly resolved Eulerian simulations of fuel spray transients in single and multi-hole injectors: Nozzle flow and near-exit dynamics. Fuel, 251, 709-729. doi:10.1016/j.fuel.2019.04.076Beheshti, N., Burluka, A. A., & Fairweather, M. (2007). Assessment of Σ−Y liq model predictions for air-assisted atomisation. Theoretical and Computational Fluid Dynamics, 21(5), 381-397. doi:10.1007/s00162-007-0052-3Chesnel, J., Reveillon, J., Menard, T., & Demoulin, F.-X. (2011). LARGE EDDY SIMULATION OF LIQUID JET ATOMIZATION. Atomization and Sprays, 21(9), 711-736. doi:10.1615/atomizspr.2012003740CMT, 2018. Virtual injection rate generator.Crua, C., Heikal, M. R., & Gold, M. R. (2015). Microscopic imaging of the initial stage of diesel spray formation. Fuel, 157, 140-150. doi:10.1016/j.fuel.2015.04.041Crua, C., Manin, J., & Pickett, L. M. (2017). On the transcritical mixing of fuels at diesel engine conditions. Fuel, 208, 535-548. doi:10.1016/j.fuel.2017.06.091Dahms, R. N., Manin, J., Pickett, L. M., & Oefelein, J. C. (2013). Understanding high-pressure gas-liquid interface phenomena in Diesel engines. 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Journal of Fluid Mechanics, 258, 31-75. doi:10.1017/s002211209400323xIlavsky, J., & Jemian, P. R. (2009). Irena: tool suite for modeling and analysis of small-angle scattering. Journal of Applied Crystallography, 42(2), 347-353. doi:10.1107/s0021889809002222Jasak, H., Weller, H. G., & Gosman, A. D. (1999). High resolution NVD differencing scheme for arbitrarily unstructured meshes. International Journal for Numerical Methods in Fluids, 31(2), 431-449. doi:10.1002/(sici)1097-0363(19990930)31:23.0.co;2-tKastengren, A., Ilavsky, J., Viera, J. P., Payri, R., Duke, D. J., Swantek, A., … Powell, C. F. (2017). Measurements of droplet size in shear-driven atomization using ultra-small angle x-ray scattering. International Journal of Multiphase Flow, 92, 131-139. doi:10.1016/j.ijmultiphaseflow.2017.03.005Kastengren, A. L., Tilocco, F. Z., Powell, C. F., Manin, J., Pickett, L. M., Payri, R., & Bazyn, T. (2012). ENGINE COMBUSTION NETWORK (ECN): MEASUREMENTS OF NOZZLE GEOMETRY AND HYDRAULIC BEHAVIOR. Atomization and Sprays, 22(12), 1011-1052. doi:10.1615/atomizspr.2013006309Kastengren, A. L., Tilocco,F. Z., Duke, D. J., Powell, C. F., Seoksu, M., Xusheng, Z., 2012b. Time-resolved x-ray radiography of diesel injectors from the engine combustion network. ICLASS Paper (1369).Kastengren, A. L., Powell, C. F., Wang, Y., Im, K.-S., & Wang, J. (2009). X-RAY RADIOGRAPHY MEASUREMENTS OF DIESEL SPRAY STRUCTURE AT ENGINE-LIKE AMBIENT DENSITY. Atomization and Sprays, 19(11), 1031-1044. doi:10.1615/atomizspr.v19.i11.30Klein, M., Sadiki, A., & Janicka, J. (2003). A digital filter based generation of inflow data for spatially developing direct numerical or large eddy simulations. Journal of Computational Physics, 186(2), 652-665. doi:10.1016/s0021-9991(03)00090-1Kraichnan, R. H. (1970). Diffusion by a Random Velocity Field. Physics of Fluids, 13(1), 22. doi:10.1063/1.1692799Lacaze, G., Misdariis, A., Ruiz, A., & Oefelein, J. C. (2015). Analysis of high-pressure Diesel fuel injection processes using LES with real-fluid thermodynamics and transport. Proceedings of the Combustion Institute, 35(2), 1603-1611. doi:10.1016/j.proci.2014.06.072Lebas, R., Menard, T., Beau, P. A., Berlemont, A., & Demoulin, F. X. (2009). Numerical simulation of primary break-up and atomization: DNS and modelling study. International Journal of Multiphase Flow, 35(3), 247-260. doi:10.1016/j.ijmultiphaseflow.2008.11.005Ma, P. C., Wu, H., Jaravel, T., Bravo, L., & Ihme, M. (2019). Large-eddy simulations of transcritical injection and auto-ignition using diffuse-interface method and finite-rate chemistry. Proceedings of the Combustion Institute, 37(3), 3303-3310. doi:10.1016/j.proci.2018.05.063Macian, V., Bermudez, V., Payri, R., & Gimeno, J. (2003). NEW TECHNIQUE FOR DETERMINATION OF INTERNAL GEOMETRY OF A DIESEL NOZZLE WITH THE USE OF SILICONE METHODOLOGY. Experimental Techniques, 27(2), 39-43. doi:10.1111/j.1747-1567.2003.tb00107.xManin, J., Bardi, M., Pickett, L. M., & Manin, J. (2012). SP2-4 Evaluation of the liquid length via diffused back-illumination imaging in vaporizing diesel sprays(SP: Spray and Spray Combustion,General Session Papers). The Proceedings of the International symposium on diagnostics and modeling of combustion in internal combustion engines, 2012.8(0), 665-673. doi:10.1299/jmsesdm.2012.8.665Matheis, J., & Hickel, S. (2018). Multi-component vapor-liquid equilibrium model for LES of high-pressure fuel injection and application to ECN Spray A. International Journal of Multiphase Flow, 99, 294-311. doi:10.1016/j.ijmultiphaseflow.2017.11.001Naber, J., Siebers, D., 1996. Effects of gas density and vaporization on penetration and dispersion of diesel sprays. SAE Technical Paper (960034).Nicoud, F., Toda, H. B., Cabrit, O., Bose, S., & Lee, J. (2011). Using singular values to build a subgrid-scale model for large eddy simulations. Physics of Fluids, 23(8), 085106. doi:10.1063/1.3623274Oefelein, J., Dahms, R., & Lacaze, G. (2012). Detailed Modeling and Simulation of High-Pressure Fuel Injection Processes in Diesel Engines. SAE International Journal of Engines, 5(3), 1410-1419. doi:10.4271/2012-01-1258Pandal, A., Pastor, J. M., Payri, R., Kastengren, A., Duke, D., Matusik, K., … Schmidt, D. (2017). Computational and Experimental Investigation of Interfacial Area in Near-Field Diesel Spray Simulation. SAE International Journal of Fuels and Lubricants, 10(2), 423-431. doi:10.4271/2017-01-0859Pandal, A., Payri, R., García-Oliver, J. M., & Pastor, J. M. (2017). Optimization of spray break-up CFD simulations by combining Σ-Y Eulerian atomization model with a response surface methodology under diesel engine-like conditions (ECN Spray A). Computers & Fluids, 156, 9-20. doi:10.1016/j.compfluid.2017.06.022Pastor, J. V., Garcia-Oliver, J. M., Pastor, J. M., & Vera-Tudela, W. (2015). ONE-DIMENSIONAL DIESEL SPRAY MODELING OF MULTICOMPONENT FUELS. Atomization and Sprays, 25(6), 485-517. doi:10.1615/atomizspr.2014010370Pickett, L. M., Manin, J., Genzale, C. L., Siebers, D. L., Musculus, M. P. B., & Idicheria, C. A. (2011). Relationship Between Diesel Fuel Spray Vapor Penetration/Dispersion and Local Fuel Mixture Fraction. SAE International Journal of Engines, 4(1), 764-799. doi:10.4271/2011-01-0686Pickett, L. M., Manin, J., Kastengren, A., & Powell, C. (2014). Comparison of Near-Field Structure and Growth of a Diesel Spray Using Light-Based Optical Microscopy and X-Ray Radiography. SAE International Journal of Engines, 7(2), 1044-1053. doi:10.4271/2014-01-1412Poinsot, T. ., & Lelef, S. . (1992). Boundary conditions for direct simulations of compressible viscous flows. Journal of Computational Physics, 101(1), 104-129. doi:10.1016/0021-9991(92)90046-2Pope, S. B. (2004). Ten questions concerning the large-eddy simulation of turbulent flows. New Journal of Physics, 6, 35-35. doi:10.1088/1367-2630/6/1/035Poursadegh, F., Lacey, J. S., Brear, M. J., & Gordon, R. L. (2017). On the Fuel Spray Transition to Dense Fluid Mixing at Reciprocating Engine Conditions. Energy & Fuels, 31(6), 6445-6454. doi:10.1021/acs.energyfuels.7b00050Ricou, F. P., & Spalding, D. B. (1961). Measurements of entrainment by axisymmetrical turbulent jets. Journal of Fluid Mechanics, 11(1), 21-32. doi:10.1017/s0022112061000834Robert, A., Martinez, L., Tillou, J., & Richard, S. (2013). Eulerian – Eulerian Large Eddy Simulations Applied to Non-Reactive Transient Diesel Sprays. Oil & Gas Science and Technology – Revue d’IFP Energies nouvelles, 69(1), 141-154. doi:10.2516/ogst/2013140Schmidt, D. P., Gopalakrishnan, S., & Jasak, H. (2010). Multi-dimensional simulation of thermal non-equilibrium channel flow. International Journal of Multiphase Flow, 36(4), 284-292. doi:10.1016/j.ijmultiphaseflow.2009.11.012Shin, D., Sandberg, R. D., & Richardson, E. S. (2017). Self-similarity of fluid residence time statistics in a turbulent round jet. Journal of Fluid Mechanics, 823, 1-25. doi:10.1017/jfm.2017.304Shinjo, J., & Umemura, A. (2010). Simulation of liquid jet primary breakup: Dynamics of ligament and droplet formation. International Journal of Multiphase Flow, 36(7), 513-532. doi:10.1016/j.ijmultiphaseflow.2010.03.008Taub, G. N., Lee, H., Balachandar, S., & Sherif, S. A. (2013). A direct numerical simulation study of higher order statistics in a turbulent round jet. Physics of Fluids, 25(11), 115102. doi:10.1063/1.4829045Trask, N., Schmidt, D. P., Lightfoot, M., & Danczyk, S. (2012). Compressible Modeling of the Internal Two-Phase Flow in a Gas-Centered Swirl Coaxial Fuel Injector. Journal of Propulsion and Power, 28(4), 685-693. doi:10.2514/1.b34102Wehrfritz, A., Kaario, O., Vuorinen, V., & Somers, B. (2016). Large Eddy Simulation of n-dodecane spray flames using Flamelet Generated Manifolds. Combustion and Flame, 167, 113-131. doi:10.1016/j.combustflame.2016.02.019Weller, H. G., Tabor, G., Jasak, H., & Fureby, C. (1998). A tensorial approach to computational continuum mechanics using object-oriented techniques. Computers in Physics, 12(6), 620. doi:10.1063/1.168744Xue, Q., Battistoni, M., Powell, C. F., Longman, D. E., Quan, S. P., Pomraning, E., … Som, S. (2015). An Eulerian CFD model and X-ray radiography for coupled nozzle flow and spray in internal combustion engines. International Journal of Multiphase Flow, 70, 77-88. doi:10.1016/j.ijmultiphaseflow.2014.11.012Xue, Q., Som, S., Senecal, P. K., & Pomraning, E. (2013). LARGE EDDY SIMULATION OF FUEL-SPRAY UNDER NON-REACTING IC ENGINE CONDITIONS. Atomization and Sprays, 23(10), 925-955. doi:10.1615/atomizspr.201300832

Computational and Experimental Investigation of Interfacial Area in Near-Field Diesel Spray Simulation

[EN] The dense spray region in the near-field of diesel fuel injection remains an enigma. This region is difficult to interrogate with light in the visible range and difficult to model due to the rapid interaction between liquid and gas. In particular, modeling strategies that rely on Lagrangian particle tracking of droplets have struggled in this area. To better represent the strong interaction between phases, Eulerian modeling has proven particularly useful. Models built on the concept of surface area density are advantageous where primary and secondary atomization have not yet produced droplets, but rather form more complicated liquid structures. Surface area density, a more general concept than Lagrangian droplets, naturally represents liquid structures, no matter how complex. These surface area density models, however, have not been directly experimentally validated in the past due to the inability of optical methods to elucidate such a quantity. Optical diagnostics traditionally measure near-spherical droplet size far downstream, where the spray is optically thin. Using ultra-small-angle x-ray scattering (USAXS) measurements to measure the surface area and x-ray radiography to measure the density, we have been able to test one of the more speculative parts of Eulerian spray modeling. The modeling and experimental results have been combined to provide insight into near-field spray dynamics.Authors acknowledge that part of this work was partially funded by the Spanish Ministry of Economy and Competitiveness in the frame of the COMEFF (TRA2014-59483-R) project.Pandal, A.; Pastor Enguídanos, JM.; Payri, R.; Kastengren, A.; Duke, DJ.; Matusik, KE.; Giraldo-Valderrama, JS.... (2017). Computational and Experimental Investigation of Interfacial Area in Near-Field Diesel Spray Simulation. SAE International Journal of Fuel and Lubricants. 10(2):1-9. doi:10.4271/2017-01-0859S1910

Building a Robust, Densely-Sampled Spider Tree of Life for Ecosystem Research

Phylogenetic relatedness is a key diversity measure for the analysis and understanding of how species and communities evolve across time and space. Understanding the nonrandom loss of species with respect to phylogeny is also essential for better-informed conservation decisions. However, several factors are known to influence phylogenetic reconstruction and, ultimately, phylogenetic diversity metrics. In this study, we empirically tested how some of these factors (topological constraint, taxon sampling, genetic markers and calibration) affect phylogenetic resolution and uncertainty. We built a densely sampled, species-level phylogenetic tree for spiders, combining Sanger sequencing of species from local communities of two biogeographical regions (Iberian Peninsula and Macaronesia) with a taxon-rich backbone matrix of Genbank sequences and a topological constraint derived from recent phylogenomic studies. The resulting tree constitutes the most complete spider phylogeny to date, both in terms of terminals and background information, and may serve as a standard reference for the analysis of phylogenetic diversity patterns at the community level. We then used this tree to investigate how partial data affect phylogenetic reconstruction, phylogenetic diversity estimates and their rankings, and, ultimately, the ecological processes inferred for each community. We found that the incorporation of a single slowly evolving marker (28S) to the DNA barcode sequences from local communities, had the highest impact on tree topology, closely followed by the use of a backbone matrix. The increase in missing data resulting from combining partial sequences from local communities only had a moderate impact on the resulting trees, similar to the difference observed when using topological constraints. Our study further revealed substantial differences in both the phylogenetic structure and diversity rankings of the analyzed communities estimated from the different phylogenetic treatments, especially when using non-ultrametric trees (phylograms) instead of time-stamped trees (chronograms). Finally, we provide some recommendations on reconstructing phylogenetic trees to infer phylogenetic diversity within ecological studies

Nutrición en cuidados paliativos: resumen de recomendaciones del Grupo de Trabajo de Ética de la SENPE

Los cuidados paliativos proporcionan una atención integral que tiene en cuenta los aspectos físicos, emocionales, sociales y espirituales del paciente con enfermedad terminal y su entorno familiar. El tratamiento nutricional debe formar parte activa de los equipos de cuidados paliativos. La necesidad de iniciar o no un tratamiento nutricional sigue siendo, desde hace décadas, uno de los principales problemas éticos a los que se enfrentan los profesionales dedicados a la nutrición clínica. El origen de tal controversia radica, fundamentalmente, en cómo se consideran la nutrición y la hidratación: cuidado/soporte o tratamiento médico. Los objetivos fundamentales del tratamiento nutricional en los pacientes en cuidados paliativos deben ser otros: la mejoría de la calidad de vida, de la supervivencia o de ambas. La decisión de indicar o no el tratamiento nutricional en cuidados paliativos debe tomarse tras considerar el pronóstico, la calidad de vida y la relación “riesgo/beneficio”. En relación a la alimentación por vía oral (con o sin suplementos orales), prevalece la idea de la “alimentación de confort”, que se basa en intentos de alimentación oral hasta que se produzcan la incomodidad y/o el rechazo del paciente. No existen evidencias que justifiquen el uso de nutrientes específicos, aunque desde hace años se señala la posibilidad de lograr beneficios cuando se utilizan ácidos grasos omega-3 en los pacientes con cáncer. En cuanto al tratamiento nutricional (enteral o parenteral), en ausencia de evidencia, las decisiones sobre si iniciar una nutrición artificial en un paciente paliativo deben tomarse teniendo en cuenta los deseos y creencias del paciente y sus familiares, y basarse en el consenso del equipo interdisciplinar sobre los objetivos que se persiguen al iniciarla

Mitochondrial discordance in closely related Theridion spiders (Araneae, Theridiidae), with description of a new species of the T. melanurum group

The incorporation of molecular data into current taxonomic practise has unravelled instances of incongruence among different data sets. Here we report a case of mitochondrial discordance in cobweb spiders of the genus Theridion Walckenaer, 1805 from the Iberian Peninsula. Morphological examination of samples from a country-wide bioinventory initiative revealed the existence of a putative new species and two nominal species belonging to the Theridion melanurum species group. The morphological delineation was supported by the molecular analysis of a nuclear marker but was at odds with the groups circumscribed by a mitochondrial marker. The causes of this discordance remained uncertain, once sample and sequencing errors and the existence of pseudogenes were discarded. The full sorting observed in the alleles of the more slowly evolving nuclear marker ruled out incomplete lineage sorting, while the geographic patterns recovered were difficult to reconciliate with ongoing hybridization. We propose that the apparent incongruence observed is most likely the result of old introgression events in a group with high dispersal abilities. We further speculate that endosymbiont-driven cytoplasmatic incompatibility could be involved in the fixation of mitochondrial haplotypes across species barriers. Additionally, we describe the new species T. promiscuum sp. nov., based on the presence of diagnostic morphological traits, backed up by the nuclear data delimitation. Our study contributes yet another example of the perils of relying on single methods or data sources to summarise the variation generated by multiple processes acting through thousands of years of evolution and supports the key role of biological inventories in improving our knowledge of invertebrate biodiversity