Preliminary observations on the feeding habits and habitats of crossbills Loxia curvirostra balearica a la península de Formentor, Mallorca

Preliminary observations on the feeding habits and habitats of Crossbills Loxia curvirostra balearica at Cape Formentor, Majorca. A study of the feeding habits and habitats of crossbills Loxia curvirostra balearica was carried out, primarily in Aleppo Pine Pinus halepensis forests on Cape Formentor, Majorca in October 2002. Crossbills either removed green cones (those that would shed seeds in the following year) from live trees, or left them in situ on a fire-damaged tree, prior to prising back the scales to remove the seeds. Cones that were removed had an average length of 44.1 mm (range 28-59 mm) and most (92.6%) had all the scales prised back. Proximal scales were prised back before the distal ones. Aleppo Pine cones have thick stalks and may pose a limit to the size of cones that crossbills can remove, because cones over 90 mm in length occur. The crossbills fed in overstorey trees with an average diameter at breast height of 43 cm and height of 16.3 m. The average density of surrounding pines was 223 trees per ha. These values were similar to the available overstorey trees.Observacions preliminars del comportament i de l'hàbitat alimentaris del trencapinyons Loxia curvirostra balearica a la península de Formentor, Mallorca. L'octubre de 2002 es va realitzar un estudi de l'ecologia alimentària del trencapinyons en els boscos de pi blanc Pinus halepensis de la península de Formentor, Mallorca. Els trencapinyons aprofitaren tant pinyes verdes (aquelles que haurien deixat anar els pinyons l'any següent) d'arbres vius com pinyes d'arbres cremats, separant les esquames i extreient les llavors. Les pinyes usades tengueren una longitud mitjana de 44,1 mm (rang de 28-59 mm) i en la majoria (92,6%) es trobaren totes les esquames separades. Les esquames proximals foren separades abans que les distals. Els trencapinyons semblen seleccionar per alimentar-se les pinyes més petites, atès que se'n poden trobar de més de 90 mm de longitud; els peduncles (tiges) gruixats de les pinyes podrien suposar un límit al tamany de pinya explotable. Els trencapinyons s'alimentaren en arbres amb un diàmetre mitjà del tronc a l'altura del pit (DBH) de 43 cm i altura mitjana de 16,3 m. La densitat mitjana de pins als voltants dels pins visitats fou de 223 arbres/ha. Aquets valors foren similars als dels arbres madurs amb provisió de pinyes disponibles

A complex speciation-richness relationship in a simple neutral model

Speciation is the "elephant in the room" of community ecology. As the ultimate source of biodiversity, its integration in ecology's theoretical corpus is necessary to understand community assembly. Yet, speciation is often completely ignored or stripped of its spatial dimension. Recent approaches based on network theory have allowed ecologists to effectively model complex landscapes. In this study, we use this framework to model allopatric and parapatric speciation in networks of communities and focus on the relationship between speciation, richness, and the spatial structure of communities. We find a strong opposition between speciation and local richness, with speciation being more common in isolated communities and local richness being higher in more connected communities. Unlike previous models, we also find a transition to a positive relationship between speciation and local richness when dispersal is low and the number of communities is small. Also, we use several measures of centrality to characterize the effect of network structure on diversity. The degree, the simplest measure of centrality, is found to be the best predictor of local richness and speciation, although it loses some of its predictive power as connectivity grows. Our framework shows how a simple neutral model can be combined with network theory to reveal complex relationships between speciation, richness, and the spatial organization of populations.Comment: 9 pages, 5 figures, 1 table, 50 reference

Non-invasive genotyping and spatial mark-recapture methods to estimate European pine marten density in forested landscapes

Accurate population density estimates are important for conservation but can be difficult to obtain where species are elusive or rare. Non-invasive genotyping from hair or faeces has provided a promising solution and allowed individual identification from genotypes to inform population assessment models. We use individual genotypes derived from hair samples and Spatially Explicit Capture Recapture (SECR) models to estimate the population density of European pine marten (Martes martes) in three Scottish forests, then examine the effects of forest fragmentation on population size. Relative trends in pine marten abundance can be observed via changes in the number of scats in an area through time, but the link between this measure and population density remains unclear. We provide the first calibration of scat counts to enable population density estimation without the need for genetic analysis. Population density estimates ranged from 0.07 km-2 (95% CI 0.03 – 0.16) to 0.38 km-2 (95% CI 0.11 – 1.07), which were mid to low compared to other estimates from the Scottish population. An unequal sex ratio was found in one of the three forests. We found support for the previous finding that pine marten density in Scotland increases with forest fragmentation up to a threshold level (20 – 35% forest cover), beyond which it decreases. Our calibration suggests a non-linear relationship between scat counts and population density, although relatively small changes in population density result in marked changes in scat number. Following the recent re-introduction of pine martens to Wales, non-invasive genetic sampling for population estimation may provide an effective way of monitoring their progress

Irruptions of crossbills Loxia spp. in northern Europe – patterns and correlations with seed production by key and non‐key conifers

Irruptions by boreal seed-eating and frugivorous birds are assumed to be driven by the production of seeds and fruits, crops of which are highly variable between years. Using data from Sweden, we tested whether irruptions of Common Crossbills Loxia curvirostra were correlated with low Norway Spruce Picea abies seed production in the same year as the irruption and/or high seed production in the year prior to an irruption. Similar tests were made for Parrot Crossbill Loxia pytyopsittacus irruptions in relation to Scots Pine Pinus sylvestris seed production. In northern Europe, these conifers represent the key food species of the two crossbill species, respectively. Despite differing times that seeds take to mature and asynchronous seed production between the two conifer species, including a 3-year cycle for Norway Spruce, the two crossbill species often irrupted in the same year as one another. Analyses showed that irruptions into Britain and other parts of western Europe by both crossbill species were correlated with low seed production by Norway Spruce in Sweden. Low seed production by Scots Pine had a marginally non-significant additive effect on both crossbill species. In a second set of analyses, the best-fitting model was one in which low seed production by both conifers in a given year and high seed production in the previous year were each correlated with large numbers of irrupting Common and Parrot Crossbills. The models indicate that the incidental co-occurrence of low seed production of Norway Spruce and Scots Pine in a given year, after a year of high seed production, may result in an irruption. The seed production of Norway Spruce and Scots Pine in Sweden was correlated with production by the same species in Finland, indicating widespread synchrony of cropping across northern Europe

Compressed representation of a partially defined integer function over multiple arguments

In OLAP (OnLine Analitical Processing) data are analysed in an n-dimensional cube. The cube may be represented as a partially defined function over n arguments. Considering that often the function is not defined everywhere, we ask: is there a known way of representing the function or the points in which it is defined, in a more compact manner than the trivial one

Evidence for the 125 GeV Higgs boson decaying to a pair of tau leptons

Peer reviewe

Measurement of the triple-differential cross section for photon plus jets production in proton-proton collisions at √s = 7 TeV

Peer reviewe

Search for massive resonances in dijet systems containing jets tagged as W or Z boson decays in pp collisions at √s=8 TeV

Peer reviewe

Measurement of the t-channel single-top-quark production cross section and of the |V tb| CKM matrix element in pp collisions at √s = 8 TeV

Peer reviewe

Measurement of the prompt J/psi and psi(2S) polarizations in pp collisions at sqrt(s) = 7 TeV

The polarizations of prompt J/psi and psi(2S) mesons are measured in proton-proton collisions at sqrt(s) = 7 TeV, using a dimuon data sample collected by the CMS experiment at the LHC, corresponding to an integrated luminosity of 4.9 inverse femtobarns. The prompt J/psi and psi(2S) polarization parameters lambda[theta], lambda[phi], and lambda[theta, phi], as well as the frame-invariant quantity lambda(tilde), are measured from the dimuon decay angular distributions in three different polarization frames. The J/psi results are obtained in the transverse momentum range 14 < pt < 70 GeV, in the rapidity intervals abs(y) < 0.6 and 0.6 < abs(y) < 1.2. The corresponding psi(2S) results cover 14 < pt < 50 GeV and include a third rapidity bin, 1.2 < abs(y) < 1.5. No evidence of large transverse or longitudinal polarizations is seen in these kinematic regions, which extend much beyond those previously explored