9 research outputs found

    Is microclimate-driven turnover of dung beetle assemblage structure in regenerating coastal vegetation a precursor to re-establishment of a forest fauna?

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    We questioned the capability of post-mining rehabilitation and successional changes in coastal vegetation to achieve restoration of dune forest, dung beetle assemblages in the Maputaland Centre of Endemism, South Africa. A repeat 2010 study of structural turnover between dung beetle assemblages across a 33 year successional sere of rehabilitating vegetation and old-growth forest (>73 years) produced comparable results to an earlier study across the 23 year chronosequence of 2000. Despite overlap, three structural patterns along the 33 year chronosequence were associated with specific stages of vegetation succession and their characteristic microclimates as in 2000. Although species biased to unshaded habitat dominated the earliest succession, there was rapid re-establishment of dominance by shade-associated forest species. In concert with progression from unshaded, post-mining vegetation to strongly shaded, early successional, Acacia shrub-woodland, there was an initial increase in similarity of the dung beetle fauna (species-poor, low abundance) to that in strongly-shaded forest (also species-poor, low abundance). However, in concert with decreasing shade cover in late successional woodland, the dung beetle fauna became species-rich with high abundance so that the early successional trajectory of increasing similarity to forest fauna either levelled off to a plateau (species in 2000; abundance in 2010) or declined (species in 2010, abundance in 2000). It remains to be seen if gaps forming in the oldest Acacia woodland permit forest tree saplings of the exposed understorey to recreate a forest canopy that would be tracked by dung beetles to re-establish a typically species-poor, deep shade, forest assemblage with low abundance.The study was funded through grants to RJvA from Richards Bay Minerals, the Department of Trade and Industry (THRIP), and the National Research Foundation (NRF).http://www.springerlink.com/content/100177/hb2013ab201

    Imperfect Isolation: Factors and Filters Shaping Madagascar’s Extant Vertebrate Fauna

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    Biological Processes Studied by Ultrafast Laser Techniques

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    Measurement of matter–antimatter differences in beauty baryon decays

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    Differences in the behaviour of matter and antimatter have been observed in K and B meson decays, but not yet in any baryon decay. Such differences are associated with the non-invariance of fundamental interactions under the combined charge-conjugation and parity transformations, known as CP violation. Here, using data from the LHCb experiment at the Large Hadron Collider, we search for CP-violating asymmetries in the decay angle distributions of Lambda(0)(b) baryons decaying to p pi(-) pi(+) pi(-) and p pi(-) K+K- final states. These four-body hadronic decays are a promising place to search for sources of CP violation both within and beyond the standard model of particle physics. We find evidence for CP violation in Lambda(0)(b) to p pi(-) pi(+) pi(-) decays with a statistical significance corresponding to 3.3 standard deviations including systematic uncertainties. This represents the first evidence for CP violation in the baryon sector

    Observation of J /ψp Resonances Consistent with Pentaquark States in Λb0 →j /ψK-p Decays

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    Observations of exotic structures in the J/ψp channel, which we refer to as charmonium-pentaquark states, in Λb0→J/ψK-p decays are presented. The data sample corresponds to an integrated luminosity of 3fb-1 acquired with the LHCb detector from 7 and 8 TeV pp collisions. An amplitude analysis of the three-body final state reproduces the two-body mass and angular distributions. To obtain a satisfactory fit of the structures seen in the J/ψp mass spectrum, it is necessary to include two Breit-Wigner amplitudes that each describe a resonant state. The significance of each of these resonances is more than 9 standard deviations. One has a mass of 4380±8±29MeV and a width of 205±18±86MeV, while the second is narrower, with a mass of 4449.8±1.7±2.5MeV and a width of 39±5±19MeV. The preferred JP assignments are of opposite parity, with one state having spin 3/2 and the other 5/2

    Measurement of the Ratio of Branching Fractions B (B ¯ 0 →d∗+τ- ν ¯ τ) / B (B ¯ 0 →d∗+μ- ν ¯ μ)

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    he branching fraction ratio R(D∗)≡B(B¯0→D∗+τ-ν¯τ)/B(B¯0→D∗+μ-ν¯μ) is measured using a sample of proton-proton collision data corresponding to 3.0fb-1 of integrated luminosity recorded by the LHCb experiment during 2011 and 2012. The tau lepton is identified in the decay mode τ-→μ-ν¯μντ. The semitauonic decay is sensitive to contributions from non-standard-model particles that preferentially couple to the third generation of fermions, in particular, Higgs-like charged scalars. A multidimensional fit to kinematic distributions of the candidate B¯0 decays gives R(D∗)=0.336±0.027(stat)±0.030(syst). This result, which is the first measurement of this quantity at a hadron collider, is 2.1 standard deviations larger than the value expected from lepton universality in the standard model

    LHCb detector performance

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    The LHCb detector is a forward spectrometer at the Large Hadron Collider (LHC) at CERN. The experiment is designed for precision measurements of CP violation and rare decays of beauty and charm hadrons. In this paper the performance of the various LHCb sub-detectors and the trigger system are described, using data taken from 2010 to 2012. It is shown that the design criteria of the experiment have been met. The excellent performance of the detector has allowed the LHCb collaboration to publish a wide range of physics results, demonstrating LHCb's unique role, both as a heavy flavour experiment and as a general purpose detector in the forward region
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