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Independent Evidence (independent + evidence)
Selected AbstractsCorrelative and mechanistic models of species distribution provide congruent forecasts under climate changeCONSERVATION LETTERS, Issue 3 2010Michael R. Kearney Abstract Good forecasts of climate change impacts on extinction risks are critical for effective conservation management responses. Species distribution models (SDMs) are central to extinction risk analyses. The reliability of predictions of SDMs has been questioned because models often lack a mechanistic underpinning and rely on assumptions that are untenable under climate change. We show how integrating predictions from fundamentally different modeling strategies produces robust forecasts of climate change impacts on habitat and population parameters. We illustrate the principle by applying mechanistic (Niche Mapper) and correlative (Maxent, Bioclim) SDMs to predict current and future distributions and fertility of an Australian gliding possum. The two approaches make congruent, accurate predictions of current distribution and similar, dire predictions about the impact of a warming scenario, supporting previous correlative-only predictions for similar species. We argue that convergent lines of independent evidence provide a robust basis for predicting and managing extinctions risks under climate change. [source] Fault interactions and subduction tectonics: a re-examination of the Weber, New Zealand, earthquake sequence of 1990GEOPHYSICAL JOURNAL INTERNATIONAL, Issue 3 2003Russell Robinson SUMMARY Two moderate magnitude (Mw= 6.2 and 6.4) earthquakes in the Hikurangi subduction margin, North Island, New Zealand, occurred 3 months apart in 1990. The epicentres are nearly coincident, but the first (Weber 1, primarily normal faulting) occurred within the subducting Pacific Plate (depth about 28 km) and the second (Weber 2, a mix of thrusting and right-lateral motion) occurred within the overlying Australian Plate (depth about 13 km), the plate interface in between. The plate interface is interpreted to be locked trenchward (SE) from about the position of these events, with a transition to aseismic slip further down-dip to the NW. Several stress interaction questions are examined. First, to see whether Weber 1 triggered Weber 2, a range of possible mainshock parameters are used to calculate induced changes in the static Coulomb failure stress (,CFS). In most cases the results are consistent with triggering. Secondly, previous work showed that the rate of aftershock occurrence for Weber 1 decreased markedly about 35 days before Weber 2, recovering afterwards. To see whether aseismic pre-slip on the Weber 2 fault, as predicted by rate and state friction, could be the cause of the decrease, the same fault parameters have been used in reverse. The results are ambiguous, some fault parameters giving results consistent with the hypothesis and others not. The amount of pre-slip required for significant inhibition, however, is about equal to that in the mainshock and distributed over the entire fault plane. Thirdly, observations of episodic, aseismic slip down-dip from locked sections of other plate interfaces are becoming more common. Could such slip have triggered both Weber events? The induced changes in CFS for such slip are uniformly positive on the Weber 1 fault plane, and mostly positive on the Weber 2 fault plane, so the answer is yes. Although there is no independent evidence for aseismic slip prior to the Weber sequence, this case shows that such slip may trigger events on other nearby faults, besides loading the locked section of the plate interface. Static stress triggering considerations are thus likely to be important in subduction environments. [source] A qualitative study of adaptation to the euro in the Republic of Ireland: I. attitudes, the ,euro illusion' and the perception of pricesJOURNAL OF COMMUNITY & APPLIED SOCIAL PSYCHOLOGY, Issue 2 2005Rob Ranyard Abstract This is the first of two reports of a study using semi-structured, in-depth interviews to explore the current and recollected experiences of Irish people for the period before, during, and after the introduction of euro notes and coins (1 January 2002). Twenty-four adults, 12 males and 12 females, covering a range of ages and educational attainment, were interviewed between October 2002 and February 2003. We found that most had welcomed the new currency initially, though some had felt less positive about it, whilst current experiences were more mixed. People's explanations for their attitudes seemed to focus more on the economic and practical aspects of currency change rather than symbolic meanings. Initially, most had experienced a euro illusion (prices in euros seeming to be more expensive than in punts). However, for most, the strength of the illusion appeared to diminish quite quickly. Nonetheless, current prices were believed to be higher, and many respondents attributed this either directly or indirectly to the change of currency. Although independent evidence found that there had been price increases in certain sectors, it was concluded that perceived price rises were, in part, illusory, and driven by expectations and selective price monitoring. Copyright © 2005 John Wiley & Sons, Ltd. [source] The modified CAMDEX informant interview is a valid and reliable tool for use in the diagnosis of dementia in adults with Down's syndromeJOURNAL OF INTELLECTUAL DISABILITY RESEARCH, Issue 6 2004S. L. Ball Abstract Background Dementia because of Alzheimer's disease (AD) commonly affects older adults with Down's syndrome (DS). Methods are needed, with established concurrent and predictive validity, to facilitate the diagnostic assessment of dementia, when it is complicated by pre-existing intellectual disabilities (ID). We report on the reliability and validity of a modified version of the Cambridge Examination for Mental Disorders of the Elderly (CAMDEX) informant interview, for use when assessing people with DS suspected as having dementia. Methods As part of a previous epidemiological study of older people with DS, the CAMDEX informant interview was used to determine the prevalence of dementia. The 74 people with DS included at that time (Time 1) had also completed the Cambridge Cognitive Examination (CAMCOG), the neuropsychological assessment from the CAMDEX schedule. Fifty-six were assessed again 6 years later (Time 2). Based on the CAMDEX informant interview, nine of the 74 at Time 1, and 11 of the 56 at Time 2, were found to meet clinical criteria for AD. Forty-one scored above floor on the CAMCOG at Time 1 and were included in the analysis of cognitive decline. Concurrent validity was established by comparing diagnosis at Time 2 with independent evidence of objective decline on cognitive tasks since Time 1. Predictive validity was established by examining how accurately diagnosis at Time 1 predicted both cognitive decline and future diagnosis. Inter-rater reliability was determined by comparing the level of agreement between two raters. Results CAMDEX-based diagnosis of AD was shown to be consistent with objectively observed cognitive decline (good concurrent validity) and to be a good predictor of future diagnosis. Although numbers are small, some support is also provided for the accuracy with which diagnosis predicts cognitive decline. Inter-rater reliability was good with Kappa > 0.8 for 91% of items and >,0.6 for all items. Conclusions The use of the modified CAMDEX informant interview enables the structured collection of diagnostic information, so that a valid and a reliable diagnosis of dementia can be made in those with pre-existing ID, using established diagnostic criteria. [source] The endosymbiont community as taxonomic character: a novel approach to resolving the Bemisia tabaci complexMOLECULAR ECOLOGY, Issue 19 2010JULIE K. STAHLHUT In this issue of Molecular Ecology, Gueguen et al. (2010) describe their novel approach to resolving cryptic genetic diversity in the Bemisia tabaci complex (Hemiptera: Aleyrodidae.) Complexes of cryptic species present a challenge to both morphological and molecular taxonomy , the former presumed, as shared morphology normally defines species as cryptic, but the latter also problematic when host DNA sequence data is either inconclusive or unaccompanied by independent evidence. Endosymbiont associations with insect hosts have, historically, complicated efforts to develop a robust molecular taxonomy, but the approach of Gueguen et al. takes advantage of endosymbiont community composition to help rather than hinder the task of resolving taxonomic distinctions within the B. tabaci complex. [source] Diversity of algal endosymbionts (zooxanthellae) in octocorals: the roles of geography and host relationshipsMOLECULAR ECOLOGY, Issue 8 2005M. J. H. VAN OPPEN Abstract The presence, genetic identity and diversity of algal endosymbionts (Symbiodinium) in 114 species from 69 genera (20 families) of octocorals from the Great Barrier Reef (GBR), the far eastern Pacific (EP) and the Caribbean was examined, and patterns of the octocoral,algal symbiosis were compared with patterns in the host phylogeny. Genetic analyses of the zooxanthellae were based on ribosomal DNA internal transcribed spacer 1 (ITS1) region. In the GBR samples, Symbiodinium clades A and G were encountered with A and G being rare. Clade B zooxanthellae have been previously reported from a GBR octocoral, but are also rare in octocorals from this region. Symbiodinium G has so far only been found in Foraminifera, but is rare in these organisms. In the Caribbean samples, only Symbiodinium clades B and C are present. Hence, Symbiodinium diversity at the level of phylogenetic clades is lower in octocorals from the Caribbean compared to those from the GBR. However, an unprecedented level of ITS1 diversity was observed within individual colonies of some Caribbean gorgonians, implying either that these simultaneously harbour multiple strains of clade B zooxanthellae, or that ITS1 heterogeneity exists within the genomes of some zooxanthellae. Intracladal diversity based on ITS should therefore be interpreted with caution, especially in cases where no independent evidence exists to support distinctiveness, such as ecological distribution or physiological characteristics. All samples from EP are azooxanthellate. Three unrelated GBR taxa that are described in the literature as azooxanthellate (Junceella fragilis, Euplexaura nuttingi and Stereonephthya sp. 1) contain clade G zooxanthellae, and their symbiotic association with zooxanthellae was confirmed by histology. These corals are pale in colour, whereas related azooxanthellate species are brightly coloured. The evolutionary loss or gain of zooxanthellae may have altered the light sensitivity of the host tissues, requiring the animals to adopt or reduce pigmentation. Finally, we superimposed patterns of the octocoral,algal symbiosis onto a molecular phylogeny of the host. The data show that many losses/gains of endosymbiosis have occurred during the evolution of octocorals. The ancestral state (azooxanthellate or zooxanthellate) in octocorals remains unclear, but the data suggest that on an evolutionary timescale octocorals can switch more easily between mixotrophy and heterotrophy compared to scleractinian corals, which coincides with a low reliance on photosynthetic carbon gain in the former group of organisms. [source] On the properties of young multiple starsMONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, Issue 2 2004E. J. Delgado-Donate ABSTRACT We present numerical results on the properties of young binary and multiple stellar systems. Our analysis is based on a series of smoothed particle hydrodynamics (SPH) +N -body simulations of the fragmentation of small molecular clouds, which fully resolve the opacity limit for fragmentation. These simulations demonstrate that multiple star formation is a major channel for star formation in turbulent flows. We have produced a statistically significant number of stable multiple systems, with component separations in the range ,1,103 au. At the end of the hydrodynamic stage (0.5 Myr), we find that ,60 per cent of stars and brown dwarfs are members of multiples systems, with about a third of these being low-mass, weakly bound outliers in wide eccentric orbits. Our results imply that in the stellar regime most stars are in multiples (,80 per cent) and that this fraction is an increasing function of primary mass. After N -body integration to 10.5 Myr, the percentage of bound objects has dropped to about 40 per cent, this decrease arising mostly from very low-mass stars and brown dwarfs that have been released into the field. Brown dwarfs are never found to be very close companions to stars (the brown dwarf desert at very small separations), but one case exists of a brown dwarf companion at intermediate separations (10 au). Our simulations can accommodate the existence of brown dwarf companions at large separations, but only if the primaries of these systems are themselves multiples. We have compared the outcome of our simulations with the properties of real stellar systems as deduced from the infrared colour,magnitude diagram of the Praesepe cluster and from spectroscopic and high-resolution imaging surveys of young clusters and the field. We find that the spread of the observed main sequence of Praesepe in the 0.4,1 M, range appears to require that stars are indeed commonly assembled into high-order multiple systems. Similarly, observational results from Taurus and , Ophiuchus, or moving groups such as TW Hydrae and MBM 12, suggest that companion frequencies in young systems can indeed be as high as we predict. The comparison with observational data also illustrates two problems with the simulation results. First, low mass ratio (q < 0.2) binaries are not produced by our models, in conflict with both the Praesepe colour,magnitude diagram and independent evidence from field binary surveys. Secondly, very low-mass stars and brown dwarf binaries appear to be considerably underproduced by our simulations. [source] Climate cooling promoted the expansion and radiation of a threatened group of South American orchids (Epidendroideae: Laeliinae)BIOLOGICAL JOURNAL OF THE LINNEAN SOCIETY, Issue 3 2010ALEXANDRE ANTONELLI The Brazilian Cerrado is the most species-rich tropical savanna in the world. Within this biome, the Campos Rupestres (,rocky savannas') constitute a poorly studied and highly threatened ecosystem. To better understand how plants characteristic of this vegetation have evolved and come to occupy the now widely-separated patches of rocky formations in eastern Brazil, we reconstruct the biogeographical history of the rare orchid genus Hoffmannseggella. We apply parsimony and Bayesian methods to infer the phylogenetic relationships among 40 out of the 41 described species. Absolute divergence times are calculated under penalized likelihood and compared with estimates from a Bayesian relaxed clock. Ancestral ranges are inferred for all nodes of the phylogeny using Fitch optimization and statistical dispersal vicariance analysis. In all analyses, phylogenetic uncertainty is taken into account by the independent analysis of a large tree sample. The results obtained indicate that Hoffmannseggella underwent rapid radiation around the Middle/Late Miocene (approximately 11,14 Mya). The region corresponding today to southern Minas Gerais acted as a main source area for several independent range expansions north- and eastwards via episodic corridors. These results provide independent evidence that climate cooling following the Middle Miocene Climatic Optimum (approximately 15 Mya) led to important vegetational shifts in eastern Brazil, causing an increase in the dominance of open versus closed habitats. Polyploidy following secondary contact of previously isolated populations may have been responsible for the formation of many species, as demonstrated by the high ploidy levels reported in the genus. © 2010 The Linnean Society of London, Biological Journal of the Linnean Society, 2010, 100, 597,607. [source] | ||||||||||