1,577 research outputs found

    Survey of Salamanders in Mississippi Limestone Caves

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    During 2000-2002 we surveyed for salamanders in the larger limestone caves of Mississippi, all within the Vicksburg Group rock unit. We found four species: Plethodon mississippi was the most abundant, followed by Eurycea guttolineata, Eurycea cirrigera, and Desmognathus conanti. We did not find Pseudotriton montanus in any of the caves, and question the validity of an investigator\u27s statement made nearly 45 years ago that, it is one of the most numerous salamanders in Mississippi. limestone caves. The salamander fauna we found is similar to that of the only other comprehensive survey of salamanders in Mississippi caves, conducted almost thirty years ago

    The Las Campanas IR Survey: Early Type Galaxy Progenitors Beyond Redshift One

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    (Abridged) We have identified a population of faint red galaxies from a 0.62 square degree region of the Las Campanas Infrared Survey whose properties are consistent with their being the progenitors of early-type galaxies. The optical and IR colors, number-magnitude relation and angular clustering together indicate modest evolution and increased star formation rates among the early-type field population at redshifts between one and two. The counts of red galaxies with HH magnitudes between 17 and 20 rise with a slope that is much steeper than that of the total H sample. The surface density of red galaxies drops from roughly 3000 per square degree at H = 20.5, I-H > 3 to ~ 20 per square degree at H = 20, I-H > 5. The V-I colors are approximately 1.5 magnitudes bluer on average than a pure old population and span a range of more than three magnitudes. The colors, and photometric redshifts derived from them, indicate that the red galaxies have redshift distributions adequately described by Gaussians with sigma_z ~ 0.2centerednearredshiftone,withtheexceptionthatgalaxieshaving centered near redshift one, with the exception that galaxies having V-I3$ are primarily in the 1.5 < z < 2 range. We find co-moving correlation lengths of 9-10 Mpc at z ~ 1, comparable to, or larger than, those found for early-type galaxies at lower redshifts. A simple photometric evolution model reproduces the counts of the red galaxies, with only a ~ 30% decline in the underlying space density of early-type galaxies at z ~ 1.2. We suggest on the basis of the colors, counts, and clustering that these red galaxies are the bulk of the progenitors of present day early-type galaxies.Comment: 5 pages, 3 figures, accepted for publication in the ApJ Letter

    New times, new politics: history and memory during the final years of the CPGB

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    This article examines the relationship between collective memory, historical interpretation and political identity. It focuses on the dissolution of the Communist Party of Great Britain (CPGB) as constructed through collective narrative memory, and on Marxist interpretations of history. The divisions within the party and the wider Marxist community, stretching from 1956 until 1991, were often framed around questions of historical interpretation. The events of 1989–1991 created an historical and mnemonic crisis for CPGB members who struggled to reconcile their past identities with their present situation. Unlike the outward-facing revisionism of other political parties, this was an intensely personal affair. The solution for many was to emphasise the need to find new ways to progress socialist aims, without relying on a discredited grand narrative. In contrast, other Communist parties, such as the Communist Party of Britain, which had been established (or ‘re-established’) in 1988, fared rather better. By adhering to the international party line of renewal and continued struggle, the party was able to hold its narrative together, condemning the excesses of totalitarian regimes, while reaffirming the need for international class struggle

    Cities in fiction: Perambulations with John Berger

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    This paper explores selected novels by John Berger in which cities play a central role. These cities are places, partially real and partially imagined, where memory, hope, and despair intersect. My reading of the novels enables me to trace important themes in recent discourses on the nature of contemporary capitalism, including notions of resistance and universality. I also show how Berger?s work points to a writing that can break free from the curious capacity of capitalism to absorb and feed of its critique

    Transgressing the moral economy: Wheelerism and management of the nationalised coal industry in Scotland

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    This article illuminates the links between managerial style and political economy in post-1945 Britain, and explores the origins of the 1984–1985 miners' strike, by examining in longer historical context the abrasive attitudes and policies of Albert Wheeler, Scottish Area Director of the National Coal Board (NCB). Wheeler built on an earlier emphasis on production and economic criteria, and his micro-management reflected pre-existing centralising tendencies in the industries. But he was innovative in one crucial aspect, transgressing the moral economy of the Scottish coalfield, which emphasised the value of economic security and changes by joint industrial agreement

    Tooth development and replacement in the Atlantic Cutlassfish, Trichiurus lepturus, with comparisons to other Scombroidei

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    Atlantic Cutlassfish, Trichiurus lepturus, have large, barbed, premaxillary and dentary fangs, and sharp dagger-shaped teeth in their oral jaws. Functional teeth firmly ankylose to the dentigerous bones. We used dry skeletons, histology, SEM, and micro-CT scanning to study 92 specimens of T. lepturus from the western North Atlantic to describe its dentition and tooth replacement. We identified three modes of intraosseous tooth replacement in T. lepturus depending on the location of the tooth in the jaw. Mode 1 relates to replacement of premaxillary fangs, in which new tooth germs enter the lingual surface of the premaxilla, develop horizontally, and rotate into position. We suggest that growth of large fangs in the premaxilla is accommodated by this horizontal development. Mode 2 occurs for dentary fangs: new tooth germs enter the labial surface of the dentary, develop vertically, and erupt into position. Mode 3 describes replacement of lateral teeth, in which new tooth germs enter a trench along the crest of the dentigerous bone, develop vertically, and erupt into position. Such distinct modes of tooth replacement in a teleostean species are unknown. We compared modes of replacement in T. lepturus to 20 species of scombroids to explore the phylogenetic distribution of these three replacement modes. Alternate tooth replacement (in which new teeth erupt between two functional teeth), ankylosis, and intraosseous tooth development are plesiomorphic to Bluefish + other Scombroidei. Our study highlights the complexity and variability of intraosseous tooth replacement. Within tooth replacement systems, key variables include sites of formation of tooth germs, points of entry of tooth germs into dentigerous bones, coupling of tooth germ migration and bone erosion, whether teeth develop horizontally or immediately beneath the tooth to be replaced, and how tooth eruption and ankylosis occur. Developmentally different tooth replacement processes can yield remarkably similar dentitions

    The Las Campanas Infrared Survey: Early-Type Galaxy Progenitors beyond z = 1

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    We have identified a population of faint red galaxies from a 0.62 deg^2 region of the Las Campanas Infrared Survey whose properties are consistent with their being the progenitors of early-type galaxies. The optical and IR colors, number-magnitude relation, and angular clustering together indicate modest evolution and increased star formation rates among the early-type field population at redshifts between 1 and 2. The counts of red galaxies with H magnitudes between 17 and 20 rise with a slope that is much steeper than that of the total H sample. The surface density of red galaxies drops from roughly 3000 deg^(-2) at H = 20.5, I-H > 3 to ~20 deg^(-2) at H = 20, I-H > 5. The V-I colors are approximately 1.5 mag bluer on average than a pure old population and span a range of more than 3 mag. The strength of the angular clustering of the red galaxies is an order of magnitude larger than that of the full galaxy sample. The colors, and photometric redshifts derived from them, indicate that the red galaxies have redshift distributions adequately described by Gaussians with σ_z ≃ 0.2 centered near z = 1, with the exception that galaxies having V-I 3 are primarily in the 1.5 ≾ z ≾ 2 range. We invert the angular correlation functions using these n(z) and find comoving correlation lengths of r_0 ≃ 9-10 h^(-1) Mpc at z ≃ 1, comparable to, or larger than, those found for early-type galaxies at lower redshifts. A simple photometric evolution model reproduces the counts of the red galaxies, with only an ~30% decline in the underlying space density of early-type galaxies at z ~ 1.2. The colors indicate characteristic star formation rates of ~1 M_☉ yr^(-1) per 10^(10) M_☉. We suggest on the basis of the colors, counts, and clustering that these red galaxies are the bulk of the progenitors of present-day early-type galaxies

    The Las Campanas Infrared Survey – II. Photometric redshifts, comparison with models and clustering evolution

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    The Las Campanas Infrared (LCIR) Survey, using the Cambridge Infra-Red Survey Instrument (CIRSI), reaches H∼21 over nearly 1 deg^2. In this paper we present results from 744 arcmin^2 centred on the Hubble Deep Field South for which UBVRI optical data are publicly available. Making conservative magnitude cuts to ensure spatial uniformity, we detect 3177 galaxies to H=20.0 in 744 arcmin^2 and a further 842 to H=20.5 in a deeper subregion of 407 arcmin^2. We compare the observed optical–infrared (IR) colour distributions with the predictions of semi-analytic hierarchical models and find reasonable agreement. We also determine photometric redshifts, finding a median redshift of ∼0.55. We compare the redshift distributions N(z) of E, Sbc, Scd and Im spectral types with models, showing that the observations are inconsistent with simple passive-evolution models while semi-analytic models provide a reasonable fit to the total N(z) but underestimate the number of z∼1 red spectral types relative to bluer spectral types. We also present N(z) for samples of extremely red objects (EROs) defined by optical–IR colours. We find that EROs with R-H>4 and H4 comprise ∼18 per cent of the observed galaxy population, while in semi-analytic models they contribute only ∼4 per cent. We also determine the angular correlation function w(θ) for magnitude, colour, spectral type and photometric redshift-selected subsamples of the data and use the photometric redshift distributions to derive the spatial clustering statistic ξ(r) as a function of spectral type and redshift out to z∼1.2. Parametrizing ξ(r) by ξ(rc,z)=[rc/r∗(z)]^(-1.8), where r_c is in comoving coordinates, we find that r∗(z) increases by a factor of 1.5–2 from z=0 to z∼1.2. We interpret this as a selection effect – the galaxies selected at z∼1.2 are intrinsically very luminous, about 1–1.5 mag brighter than L∗. When galaxies are selected by absolute magnitude, we find no evidence for evolution in r∗ over this redshift range. Extrapolated to z=0, we find r∗(z=0)∼6.5 h^(-1) Mpc for red galaxies and r∗(z=0)∼2–4 h^(-1) Mpc for blue galaxies. We also find that, while the angular clustering amplitude of EROs with R-H>4 or I-H>3 is up to four times that of the whole galaxy population, the spatial clustering length r∗(z=1) is ∼7.5–10.5 h^(-1) Mpc, which is only a factor of ∼1.7 times r∗(z=1) for R-H<4 and I-H<3 galaxies lying in a similar redshift and luminosity range. This difference is similar to that observed between red and blue galaxies at low redshifts
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