561 research outputs found

    Clause Intertwining and Word Order in Ancient Greek

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    In Ancient Greek complex sentences consisting of a main and complement clause, constituents which semantically and syntactically belong to the complement clause can be placed in a position preceding or interrupting the main clause. This phenomenon is referred to as clause or sentence intertwining. This paper examines the pragmatic factors involved in the preposing of contituents in sentences containing an in initival complement clause. It will be argued that the specific pragmatic function of the preposed constituents is Theme (left dislocation), new/contrastive topic or narrow focus. Preposing can be analyzed as a device to pragmatically highlight the involved constituents. The paper also addresses the position of new, contrastive and given topics and of adverbs and clauses with Setting function. © 2012 BRILL

    Geochemistry and Organic Contaminants in the Sediments of Great Slave Lake, Northwest Territories, Canada

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    A study was carried out in the summer of 1987 to determine the geochemistry and distribution of trace elements, PCBs and 16 other chlorinated hydrocarbons in sediments from selected areas in Great Slave Lake, Northwest Territories, Canada. Sediment cores were collected at three sampling stations in the west basin of the lake on a transect from the Slave River delta to the outlet of the Mackenzie River. The geotechnical composition of the sediments showed the deposition of similar material at all sampling stations. Sediment dating indicated a very high sedimentation rate (46.6 g/cm²/year) at a 110 m water depth in the vicinity of the Slave River delta and mixing of bottom sediments at the southwestern part of the lake. The concentrations of trace elements (Cu, Ni, Co, Cr, V, Pb and Zn) were uniform in all sediment profiles. However, surficial sediments were enriched by arsenic, Canadian standard CLB-1 containing 51 PCB congeners was used in the determination of PCBs in the sediment. Thirty-three PCB congeners were detected and their concentrations determined in selected sections of sediment cores. The most abundant congeners were 15 and 18, 44, 49, 52 and 101 (IUPAC numbering) with maximum concentrations 3.52, 2.68, 2.44, 6.20 and 2.44, 6.20 and 2.13 ng/g respectively. The concentration pattern of PCBs in Great Slave Lake sediments indicated considerably greater quantities of lower than higher chlorinated biphenyls. Several congeners, particularly those having 7-10 chlorine atoms, were determined in concentrations smaller than 0.20 ng/g only at one sediment depth. Hexachlorobutadiene, 1, 2, 3, 4-tetrachlorobenzene, pentachlorobenzene, alpha-HCH, hexachlorobenzene, pentachloroanisol and alpha-chlordane were present at all stations at different sediment depths. Maximum concentrations of the 16 chlorinated hydrocarbons analyzed in Great Slave Lake sediments were between 0.08 and 1.04 ng/g. The concentrations of PCBs and other chlorinated hydrocarbons were about two orders of magnitude lower than those in Lake Ontario sediments.Key words: Great Slave Lake, sediments, geochemistry, PCBs, chlorinated hydrocarbonsRÉSUMÉ. Au cours de l’été de 1987, on a procédé à une étude pour déterminer la geochimie et la répartition des oligo-éléments, des BPC et de 16 autres hydrocarbures chlorts dans des sediments provenant de zones sélectionnées du Grand Lac de l’Esclave dans les Territoires du Nord-Ouest auCanada. On a prélevé des carottes de sédiments à trois postes d’échantillonnage dans le bassin ouest du lac le long d’un axe allant du delta de la rivière Slave à l’embouchure du fleuve Mackenzie. La composition géochimique des sediments a révélé un dépôt de matériau similaire à tous les postes d’échantillonnage. La datation des sédiments a montré un fort taux de sedimentation (46,6 g.cm-* par an) h 110 m sous l’eau, dans la zone du delta de la Slave, et un mélange des sédiments de fond dans la partie sud-ouest du lac. Les concentrations d’oligo-éléments (Cu, Ni, Co, Cr, V, Pb, et Zn) étaient uniformes dans tous les profils de sédiments. Les sédiments de surface cependant contenaient en plus de l’arsenic. On a utilisé des CLB-1 canadiens normalists contenant 51 congénères de BPC pour déterminer+les BPC dans les sédiments. On a détecté 33 congtntres de BPC et déterminé leurs concentrations dans des sections choisies des carottes de suiments. Les congénères les plus abondants étaient les numéros 15 et 18,44,49,52et 101 (numérotation de I’IUPAC) avec des concentrations maximales respectives de 3.52, 2.68, 2,44,6,20 et 2,13 ng.g-l. Le schéma de concentration des BPC dans les sediments du Grand Lac de l’Esclave révélé des quantités considerablement plus importantes de biphenyles peu chlorés parrapport aux biphènyles trés chlorés. On a trouvé plusieurs congénères, en particulier ceux ayant de 7 à 10 atomes de chlore, en concentrations inférieures à 0,20 ng.g” à seulement une certaine profondeur de sédiments. On a trouvé de l’hexachlorobutadiène, du tétrachlorobenzène-1,2,3,4, du pentachlorobenzène, du H.C.H.-A, de l’hexachlorobenzène, du pentachloroanisole et du chlordane-A à tous les postes à différentes profondeurs de sédiments. Les concentrations maximales des 16 hydrocarbures chlorés analysts dans les sediments du Grand Lac de l’Esclave se situaient entre 0,08 et 1,04 ng.g”. Les concentrations de BPC et d’autres hydrocarbures chlorés étaient d’environ deux ordres de grandeur inférieures à celles contenues dans les sédiments du lac Ontario.Mots clés: Grand Lac de l’Esclave, sédiments, géochimie, BPC, hydrocarbures chloré

    Prospects for radio detection of ultra-high energy cosmic rays and neutrinos

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    The origin and nature of the highest energy cosmic ray events is currently the subject of intense investigation by giant air shower arrays and fluorescent detectors. These particles reach energies well beyond what can be achieved in ground-based particle accelerators and hence they are fundamental probes for particle physics as well as astrophysics. Because of the scarcity of these high-energy particles, larger and larger ground-based detectors have been built. The new generation of digital radio telescopes may play an important role in this, if properly designed. Radio detection of cosmic ray showers has a long history but was abandoned in the 1970's. Recent experimental developments together with sophisticated air shower simulations incorporating radio emission give a clearer understanding of the relationship between the air shower parameters and the radio signal, and have led to resurgence in its use. Observations of air showers by the SKA could, because of its large collecting area, contribute significantly to measuring the cosmic ray spectrum at the highest energies. Because of the large surface area of the moon, and the expected excellent angular resolution of the SKA, using the SKA to detect radio Cherenkov emission from neutrino-induced cascades in lunar regolith will be potentially the most important technique for investigating cosmic ray origin at energies above the photoproduction cut-off. (abridged)Comment: latex, 26 pages, 17 figures, to appear in: "Science with the Square Kilometer Array," eds. C. Carilli and S. Rawlings, New Astronomy Reviews, (Elsevier: Amsterdam

    Clouds, shadows, or twilight? Mayfly nymphs recognise the difference

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    1. We examined the relative changes in light intensity that initiate night-time locomotor activity changes in nymphs of the mayfly, Stenonema modestum (Heptageniidae). Tests were carried out in a laboratory stream to examine the hypothesis that nymphs increase their locomotion in response to the large and sustained reductions in relative light intensity that take place during twilight but not to short-term daytime light fluctuations or a minimum light intensity threshold. Ambient light intensity was reduced over a range of values representative of evening twilight. Light was reduced over the same range of intensities either continuously or in discrete intervals while at the same time nymph activity on unglazed tile substrata was video recorded. 2. Nymphs increased their locomotor activity during darkness in response to large, sustained relative light decreases, but not in response to short-term, interrupted periods of light decrease. Nymphs did not recognise darkness unless an adequate light stimulus, such as large and sustained relative decrease in light intensity, had taken place. 3. We show that nymphs perceive light change over time and respond only after a lengthy period of accumulation of light stimulus. The response is much lengthier than reported for other aquatic organisms and is highly adaptive to heterogeneous stream environments

    Cutoff for the Ising model on the lattice

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    Introduced in 1963, Glauber dynamics is one of the most practiced and extensively studied methods for sampling the Ising model on lattices. It is well known that at high temperatures, the time it takes this chain to mix in L1L^1 on a system of size nn is O(log⁥n)O(\log n). Whether in this regime there is cutoff, i.e. a sharp transition in the L1L^1-convergence to equilibrium, is a fundamental open problem: If so, as conjectured by Peres, it would imply that mixing occurs abruptly at (c+o(1))log⁥n(c+o(1))\log n for some fixed c>0c>0, thus providing a rigorous stopping rule for this MCMC sampler. However, obtaining the precise asymptotics of the mixing and proving cutoff can be extremely challenging even for fairly simple Markov chains. Already for the one-dimensional Ising model, showing cutoff is a longstanding open problem. We settle the above by establishing cutoff and its location at the high temperature regime of the Ising model on the lattice with periodic boundary conditions. Our results hold for any dimension and at any temperature where there is strong spatial mixing: For Z2\Z^2 this carries all the way to the critical temperature. Specifically, for fixed d≄1d\geq 1, the continuous-time Glauber dynamics for the Ising model on (Z/nZ)d(\Z/n\Z)^d with periodic boundary conditions has cutoff at (d/2λ∞)log⁥n(d/2\lambda_\infty)\log n, where λ∞\lambda_\infty is the spectral gap of the dynamics on the infinite-volume lattice. To our knowledge, this is the first time where cutoff is shown for a Markov chain where even understanding its stationary distribution is limited. The proof hinges on a new technique for translating L1L^1 to L2L^2 mixing which enables the application of log-Sobolev inequalities. The technique is general and carries to other monotone and anti-monotone spin-systems.Comment: 34 pages, 3 figure

    Spatial competition and agglomeration in the visitor attraction sector

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    This paper provides a theoretical and empirical contribution to understanding spatial competition by examining visitor attractions in two contrasting clusters of lower and higher levels of agglomeration of businesses in Cornwall, the UK. The study found that competition is mainly for customers and labour and is related differently to the levels of agglomeration, spatial proximity and thematic product similarity between visitor attractions at the local compared to the regional scale. Location can be used differently for employing ‘weak’ and ‘strong’ competitive strategies. The study contributes to the knowledge on the spatiality of competition and the locational strategies of service businesses

    Interaction of ENSO-driven Flood Variability and Anthropogenic Changes in Driving Channel Evolution: Corryong/ Nariel Creek, Australia

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    This is an Accepted Manuscript of an article published by Taylor & Francis in Australian Geographer on 03/09/2015, available online: 10.1080/00049182.2015.1048595Understanding the relative contributions of climatic and anthropogenic drivers of channel change are important to inform river management, especially in the context of environmental change. This global debate is especially pertinent in Australia as catchments have been severely altered since recent European settlement, and there is also strong evidence of cyclical climate variability controlling environmental systems. Corryong/Nariel Creek is an ideal setting to further study the interaction between climate and anthropogenic changes on channel evolution as it has experienced both significant periods of flood and drought, controlled by the El Niño Southern Oscillation (ENSO), and extensive anthropogenic changes. Since European settlement the floodplain has been completely cleared, the riparian zone almost entirely invaded by willows, and every reach of the channel has experienced some form of direct channel modification. Through the combined analysis of channel evolution, climate changes and anthropogenic history of the river it was found that both the ENSO-driven climate and anthropogenic drivers are significant, although at different scales of channel change. Significant straightening in response to land clearing in the early twentieth century occurred before any records of direct channel modifications. Following this, most river management works were in response to instabilities created in the clearing period, or to instabilities created by flooding triggering a new phase of instability in reaches which had already undergone stabilisation works. Overall, human activities triggered channel instability via land clearing, and management works since then generally exacerbated erosion during high flows that are driven by climate fluctuations. This research raises the interesting question of whether rivers in Australia have become more responsive to the ENSO cycle since the clearing of catchment and riparian vegetation, or whether the past response to climate variability was different
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