Subjectivism as an unavoidable feature of ecological statistics

La subjetividad como característica inevitable de los análisis estadísticos en ecología En este trabajo abordamos la gestión de información previa al realizar inferencia estadística en ecología, tanto en la especificación y la selección del modelo como en la estimación de los parámetros. Comparamos las perspectivas que aplican a esta problemática la escuela Frecuentista y la Bayesiana, que comprende a los bayesianos objetivos y subjetivos. Mostramos que la problemática de utilizar información previa y tomar decisiones a priori no es solo una realidad para los bayesianos, sino también para los frecuentistas. Sin embargo, estos últimos tienden a pasar por alto esta cuestión debido a la dificultad habitual de encontrar información previa sobre la magnitud del efecto que se considera relevante desde el punto de vista biológico. Esta información previa debería utilizarse en las pruebas de potencia a priori para buscar los tamaños de muestra óptimos para alcanzar la significación estadística y biológica necesaria. Los ecólogos deberían hacer un mayor esfuerzo por hacer uso de dicha información previa, pues es su contribución más legítima al proceso inferencial. De esta manera, la estimación de parámetros y la selección de modelos se verían beneficiadas, lo que permitiría que el proceso de aprendizaje fuera más fiable y, por tanto, que las ciencias biológicas pudieran progresar.We approach here the handling of previous information when performing statistical inference in ecology, both when dealing with model specification and selection, and when dealing with parameter estimation. We compare the perspectives of this problem from the frequentist and Bayesian schools, including objective and subjective Bayesians. We show that the issue of making use of previous information and making a priori decisions is not only a reality for Bayesians but also for frequentists. However, the latter tend to overlook this because of the common difficulty of having previous information available on the magnitude of the effect that is thought to be biologically relevant. This prior information should be fed into a priori power tests when looking for the necessary sample sizes to couple statistical and biological significances. Ecologists should make a greater effort to make use of available prior information because this is their most legitimate contribution to the inferential process. Parameter estimation and model selection would benefit if this was done, allowing a more reliable accumulation of knowledge, and hence progress, in the biological sciences.La subjetividad como característica inevitable de los análisis estadísticos en ecología En este trabajo abordamos la gestión de información previa al realizar inferencia estadística en ecología, tanto en la especificación y la selección del modelo como en la estimación de los parámetros. Comparamos las perspectivas que aplican a esta problemática la escuela Frecuentista y la Bayesiana, que comprende a los bayesianos objetivos y subjetivos. Mostramos que la problemática de utilizar información previa y tomar decisiones a priori no es solo una realidad para los bayesianos, sino también para los frecuentistas. Sin embargo, estos últimos tienden a pasar por alto esta cuestión debido a la dificultad habitual de encontrar información previa sobre la magnitud del efecto que se considera relevante desde el punto de vista biológico. Esta información previa debería utilizarse en las pruebas de potencia a priori para buscar los tamaños de muestra óptimos para alcanzar la significación estadística y biológica necesaria. Los ecólogos deberían hacer un mayor esfuerzo por hacer uso de dicha información previa, pues es su contribución más legítima al proceso inferencial. De esta manera, la estimación de parámetros y la selección de modelos se verían beneficiadas, lo que permitiría que el proceso de aprendizaje fuera más fiable y, por tanto, que las ciencias biológicas pudieran progresar

Z0 Boson Measurement with the ALICE Central Barrel in pp collisions at 14 TeV

The possibility to detect the Z0 in the ALICE central barrel is studied via the electronic decay channel Z0->e+e-. The signal and the background are simulated with the leading order event generator PYTHIA 6. The total cross-sections are taken from NLO calculations. Based on test beam data, the electron identification performance of the Transition Radiation Detector is extrapolated to high momenta. The expected yields for minimum-bias pp collisions at 14 TeV are presented. An isolation cut on the single electron, together with a minimum transverse momentum cut, allows to obtain a clear signal. The expected background is of the order of 1 % with the main contribution coming from misidentified pions from jets.Comment: 4 pages, 3 figures, QM2008 proceeding

Assessment of the combined use of MSW and autochthonous tree species for the phytomanagement of mine wastes under semiarid climate

[SPA] El fitomanejo se considera una técnica adecuada para reducir los riesgos ambientales de depósitos mineros abandonados. Las enmiendas orgánicas y el empleo de árboles se han utilizado con éxito en estos suelos contaminados. El objetivo de este trabajo fue evaluar la adición de un residuos sólido urbano (RSU) en el crecimiento y fraccionamiento de metal(oid)es en dos especies arbóreas (P. halepensis y T. articulata) creciendo en residuos mineros. Para alcanzar los objetivos de este trabajo se llevó a cabo un experimento en macetas. El RSU mejoró los parámetros de fertilidad de suelo y aumentó la biomasa de ambas especies, aunque favoreció una mayor translocación de metales en P. halepensis. Se concluyó que el uso para el fitomanejo de residuos mineros de P. halepensis y T. articulata puede ser apropiado acompañado del uso de esta enmienda. [ENG] Phytomanagement is considered a suitable tool to reduce the environmental risks of abandoned mine tailings. Organic amendments and trees have been successfully used on metal contaminated land. The goal of this work was to assess the effects of Municipal Solid Waste (MSW) addition on plant growth and metal(loid) partitioning in two tree plant species (P. halepensis and T. articulata) growing on mine tailings. In order to achieve the objective of this work a pot experiment was carried out. The MSW improved soil fertility parameters and thus, plant growth in both plant species but also metal translocation in P. halepensis. It was concluded that the positive effects of MSW on plant growth may justify its employment in the phytomanagement of abandoned mine tailings.This project has been funded by MINECO-FEDER (CGL2014-54029-R, Project ECOMIN) and Seneca Foundation (19248/PI/14). Obdulia Martínez holds a FPI contract (BES-2015- 075838) from MINECO

Transcriptional responses are oriented towards different components of the rearing environment in two Drosophila sibling species

Background The chance to compare patterns of differential gene expression in related ecologically distinct species can be particularly fruitful to investigate the genetics of adaptation and phenotypic plasticity. In this regard, a powerful technique such as RNA-Seq applied to ecologically amenable taxa allows to address issues that are not possible in classic model species. Here, we study gene expression profiles and larval performance of the cactophilic siblings Drosophila buzzatii and D. koepferae reared in media that approximate natural conditions and evaluate both chemical and nutritional components of the diet. These closely related species are complementary in terms of host-plant use since the primary host of one is the secondary of the other. D. koepferae is mainly a columnar cactus dweller while D. buzzatii prefers Opuntia hosts. Results Our comparative study shows that D. buzzatii and D. koepferae have different transcriptional strategies to face the challenges posed by their natural resources. The former has greater transcriptional plasticity, and its response is mainly modulated by alkaloids of its secondary host, while the latter has a more canalized genetic response, and its transcriptional plasticity is associated with the cactus species. Conclusions Our study unveils a complex pleiotropic genetic landscape in both species, with functional links that relate detox responses and redox mechanisms with developmental and neurobiological processes. These results contribute to deepen our understanding of the role of host plant shifts and natural stress driving ecological specialization

Attitudes to kidney donation among primary care patients in rural Crete, Greece

<p>Abstract</p> <p>Background</p> <p>In Greece, there is limited research on issues related to organ donation, and the low rate of registration as donors requires explanation. This study reports the findings of a survey of knowledge and attitudes to kidney donation among primary care patients in rural Crete, Greece.</p> <p>Methods</p> <p>Two rural primary care settings in the island of Crete, Anogia Health Centre and Vrachasi Practice, were involved in a questionnaire survey. This was conducted among primary care patients (aged 18 years and over) with routine appointments, to assess their knowledge and attitudes to kidney donation. General practitioners (GPs) recruited patients and questionnaires were completed following the patients' medical consultation. Pearson's chi square tests were used and crude odds ratios (OR) with 95% confidence intervals (95% CI) were calculated in order to investigate into the possible associations between the respondents' knowledge, attitudes and specific concerns in relation to their socio-demographic features. Logistic regression analyses were used to examine differences by geographical location.</p> <p>Results</p> <p>The 224 (92.5%) of the 242 primary care attenders who were approached agreed to participate. Only 2.2% (5/224) of the respondents carried a donor card. Most participants (84.4%, 189/224) did not feel well informed about registering as a kidney donor. More than half of the respondents (54.3%, 121/223) were unwilling to register as a kidney donor and donate kidneys for transplant after death. Over a third of respondents (35.4%, 79/223) were not confident that medical teams would try as hard as possible to save the life of a person who has agreed to donate organs. People with a higher level of education were more likely to be willing to register as kidney donors [(OR: 3.3; 95% CI: 1.8–6.0), p < 0.001)] and to be less worried about their kidneys being removed after death [(OR: 0.3; 95% CI: 0.1–0.5), p < 0.001)] than those having a lower level of education.</p> <p>Conclusion</p> <p>Lack of knowledge and information regarding organ donation and negative attitudes related to registration as donors were the main findings of this study. Efforts should be based on targeting the attitudes to organ donation of individuals and population groups.</p

Metal mobility assessment in semiarid mine tailings amended with biochar and urban compost: results of a bioassay employing a pioneer plant species

[SPA] El fitomanejo permite reducir el riesgo ambiental de balsas mineras abandonadas. El objetivo del trabajo fue evaluar la movilidad de metales en balsas mineras enmendadas con biochar y/o compost urbano y la efectividad de las enmiendas reduciendo la toxicidad de la solución edáfica para una planta pionera (Zygophyllum fabago). Se llevó a cabo un experimento en mesocosmos (20 meses) con residuo minero con y sin enmienda. Los mesocosmos se mantuvieron a capacidad de campo con agua de la red y se drenaron en diferentes momentos. Se monitorizó la solución edáfica regularmente (pH, conductividad eléctrica, carbono orgánico soluble –COS--, nitrógeno total soluble –NTS- y metales -Mn, Zn-), al igual que el drenaje. Se realizó un bioensayo con semillas de Z. fabago con la solución edáfica de mitad del experimento (germinación de semillas, crecimiento de plántulas). Los tratamientos con compost urbano mostraron mayor concentración inicial de COS y metales en solución. Se observó un descenso temporal de la concentración de DOC y metales en la solución edáfica debido a su lixiviación en el drenaje. A pesar del mayor contenido de metales, el compost urbano favoreció la elongación de la raíz debido al mayor contenido de COS y NTS en solución. [ENG] Phytomanagement allows to reduce the environmental risks of abandoned mine tailings. The aim of this work was to assess metal mobility in mine tailings amended with biochar and/or urban compost and the effectiveness of these amendments for reducing the toxicity of soil solution to a pioneer plant species (Zygophyllum fabago). A mesocosm experiment was performed (20 months) with mine wastes with and without amendment. Mesocosms were maintained at field capacity with tap water and drained at different times. Soil solution was regularly monitored (pH, electrical conductivity, dissolved organic carbon –DOC-, dissolved total nitrogen –TDN- and metals -Mn, Zn-), as well as drainage. A bioassay with seeds of Z. fabago was performed with midterm soil solution (seed germination, seedling performance). Treatments containing urban compost showed higher initial DOC and metal concentrations in solution. A decrease of DOC and metal concentrations in soil solution with time occurred due to their lixiviation in the drainage water. In spite of the higher metal pool, urban compost favoured root length due to its greater content of DOC and TDN in soil solution.Financial support for this research was provided by the Ministerio de Economía y Competitividad of Spain and FEDER (Project CTM2014-54029-R) and Fundación Séneca de CARM (19248/PI/14). Obdulia Martínez holds a FPI contract from the Ministerio de Economía y Competitividad of Spain (BES-2015-075838). Dr. González-Alcaraz holds a Marie Skłodowska-Curie contract (H2020-MSCA-IF-2015, Project ID 704332)

Effect of heavy-quark energy loss on the muon differential production cross section in Pb-Pb collisions at \sqrtsNN=5.5 TeV

We study the nuclear modification factors RAA and RCP of the high transverse momentum 5<pt<60 GeV/c distribution of muons in Pb--Pb collisions at LHC energies. We consider two pseudo-rapidity ranges covered by the LHC experiments: $|\eta|<2.5$ and $2.5<\eta<4$. Muons from semi-leptonic decays of heavy quarks (c and b) and from leptonic decays of weak gauge bosons (W and Z) are the main contributions to the muon pt distribution above a few GeV/c. We compute the heavy quark contributions using available pQCD-based programs. We include the nuclear shadowing modification of the parton distribution functions and the in-medium radiative energy loss for heavy quarks, using the mass-dependent BDMPS quenching weights. Muons from W and Z leptonic decays, that dominate the yield at high pt, can be used as a medium-blind reference to observe the medium-induced suppression of beauty quarks

Incorporating Biotic Information in Species Distribution Models: A Coregionalized Approach

In this work, we discuss the use of a methodological approach for modelling spatial relationships among species by means of a Bayesian spatial coregionalized model. Inference and prediction is performed using the integrated nested Laplace approximation methodology to reduce the computational burden. We illustrate the performance of the coregionalized model in species interaction scenarios using both simulated and real data. The simulation demonstrates the better predictive performance of the coregionalized model with respect to the univariate models. The case study focus on the spatial distribution of a prey species, the European anchovy (Engraulis encrasicolus), and one of its predator species, the European hake (Merluccius merluccius), in the Mediterranean sea. The results indicate that European hake and anchovy are positively associated, resulting in improved model predictions using the coregionalized model.Postprin

Constraints for the nuclear parton distributions from Z and W production at the LHC

The LHC is foreseen to finally bring also the nuclear collisions to the TeV scale thereby providing new possibilities for physics studies, in particular related to the electro-weak sector of the Standard Model. We study here the Z and W production in proton-lead and lead-lead collisions at the LHC, concentrating on the prospects of testing the factorization and constraining the nuclear modifications of the parton distribution functions (PDFs). Especially, we find that the rapidity asymmetries in proton-nucleus collisions, arising from the differences in the PDFs between the colliding objects, provide a decisive advantage in comparison to the rapidity-symmetric nucleus-nucleus case. We comment on how such studies will help to improve our knowledge of the nuclear PDFs.Comment: The version accepted for publication in JHEP. New figures has been added, and we also discuss the single charged lepton productio