234 research outputs found

    Local Gromov-Witten Invariants are Log Invariants

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    We prove a simple equivalence between the virtual count of rational curves in the total space of an anti-nef line bundle and the virtual count of rational curves maximally tangent to a smooth section of the dual line bundle. We conjecture a generalization to direct sums of line bundles.Comment: 15 pages, version accepted for publication in Advances in Mathematic

    The influence of mass media on countryside leisure visit behaviour compared to the influence of childhood socialization: a structural model of relationships.

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    Those involved with the management of the countryside have an imperative to understand the drivers of behaviour towards it. This is particularly so, since the UK population is largely urban-based and yet still retains an attachment to green open spaces and engagement with the pastoral scene (DEFRA, 2009; Natural England, 2016). The media has been recognised as playing an important role in sustaining this attachment but its relative influence compared to the role of the family, other social groups and education is less well understood in this context. The aim of this research is to provide a measure of the influences that underpin this attachment, specifically to develop a better understanding of the role of mass media as a component of the socializing factors which influence attitudes towards leisure behaviour in the countryside. The measurement and exploration of these influences is based upon a pilot study, followed by a survey of 2775 respondents, in six urban centres in England during 2011 and 2012. The data was analysed in order to investigate the relative role of developmental and mass media influences on countryside leisure behaviour. The cognitive and emotional processes that catalyse these relationships were also evaluated. A structural model of relationships was then developed, which provided predictive measures of the formative influences upon countryside leisure behaviour. Three key findings emerged from the research. The first confirmed that interest in countryside leisure may be derived from early socialization influences but significantly there are sub-groups for whom this early experience is irrelevant. These sub-groups developed their interest in countryside in later adulthood, inspired by the cultural discourse of rural themes represented in the media. Secondly the research identified that the relative influence of early exposure to countryside interests from family and friends is weaker than the direct effect of media on current countryside visit behaviour. Thirdly the predictive relationship suggests that countryside knowledge, the normative and control influences of others and the media, work largely through emotional rather than cognitive processes in their effect upon countryside visit behaviour. A further outcome of the research identified a control influence upon attitudes and engagement with the countryside, driven by pragmatic considerations of countryside as a resource for housing and infrastructure needs. The significant findings from this research make a contribution to knowledge regarding the processes that influence countryside leisure attitudes and behaviour. Specifically, it confirms the importance of developing media strategy that reflects the emotional bond that people have with the countryside and targeting robust market segments, differentiated by media responsiveness and developmental influences. An effective media strategy is particularly important for those sections of the population, who have had little encouragement to engage with the countryside during childhood but are, in adulthood, responsive to its portrayal in the media

    Carbon stocks of three secondary coniferous forests along an altitudinal gradient on Loess Plateau in inland China

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    <div><p>Natural forests in inland China are generally distributed in montane area and secondary due to a semi-arid climate and past anthropogenic disturbances. However, quantification of carbon (C) stock in these forests and the role of altitude in determining C storage and its partition among ecosystem components are unclear. We sampled 54 stands of three secondary coniferous forests (<i>Larix principis-rupprechtii</i> (LP) forest, <i>Picea meyerii</i> (PM) forest and <i>Pinus tabulaeformis</i> (PT) forest) on Loess Plateau in an altitudinal range of 1200-2700m a.s.l. C stocks of tree layer, shrub layer, herb layer, coarse wood debris, forest floor and soil were estimated. We found these forests had relatively high total C stocks. Driven by both higher vegetation and soil C stocks, total C stocks of LP and PM forests in the high altitudinal range were 375.0 and 368.4 t C ha<sup>-1</sup> respectively, significantly higher than that of PT forest in the low altitudinal range (230.2 t C ha<sup>-1</sup>). In addition, understory shrubs accounted for about 20% of total biomass in PT forest. The proportions of vegetation to total C stock were similar among in the three forests (below 45%), so were the proportions of soil C stock (over 54%). Necromass C stocks were also similar among these forests, but their proportions to total C stock were significantly lower in LP and PM forests (1.4% and 1.6%) than in PT forest (3.0%). Across forest types, vegetation biomass and soil C stock simultaneously increased with increasing altitude, causing fairly unchanged C partitioning among ecosystem components along the altitudinal gradient. Soil C stock also increased with altitude in LP and PT forests. Forest floor necromass decreased with increasing altitude across the three forests. Our results suggest the important role of the altitudinal gradient in C sequestration and floor necromass of these three forests in terms of alleviated water conditions and in soil C storage of LP and PM forests in terms of temperature change.</p></div

    Schematic maps showing the location of the study area on the Loess Plateau, China and the mean annual temperature and precipitation changes along the altitudinal gradient on Guandi mountain range.

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    <p>MAT, mean annual temperature; MAP, mean annual precipitation. MATs and MAPs along the altitudinal gradient are presented using the estimated data given by Xiao et al.[<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0196927#pone.0196927.ref023" target="_blank">23</a>].</p

    The number of multi-label sentences in Ren_CECps.

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    <p>The number of multi-label sentences in Ren_CECps.</p

    The results of five methods in 20 newsgroup experiments.

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    <p>The results of five methods in 20 newsgroup experiments.</p

    Carbon stocks of three secondary coniferous forests along an altitudinal gradient on Loess Plateau in inland China - Fig 3

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    <p><b>CWD and forest floor necromass (a) and forest floor necromass (after natural-log transformation) along the altitudinal gradient (b) in three coniferous forests on the Loess Plateau, China.</b> LP, <i>Larix principis-rupprechtii</i> forest; PM, <i>Picea meyerii</i> forest; PT, <i>Pinus tabulaeformis</i> forest. Different letters in (a) indicate significant differences of the forest floor necromass (p<0.05) among three forest types. Solid line in (b) represents a significant linear relationship (r<sup>2</sup> = 0.16, p = 0.003) between altitude and forest floor necromass across the three forests.</p

    The results of experiments on Ren_CECps and 20 newsgroup.

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    <p>The results of experiments on Ren_CECps and 20 newsgroup.</p

    The comparison of time-consuming in WMD and fast WMD.

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    <p>The comparison of time-consuming in WMD and fast WMD.</p
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