bluuebunny/crossref_metadata_2025_split huggingface dataset:
Plant and Insect Fossils at Norwood in South-Central Minnesota: A Record of Late-Glacial Succession
Authors: Ashworth Allan C. , Schwert Donald P. , Watts William A. , Wright H.E. 
Published: December 2004

AbstractThe Norwood site in Sibley Co., Minnesota, contains 1.6 m of silt resting on till and overlain by peat. The base of the peat has been radiocarbon dated at 12,400 ± 60 and the top at 11,200 ± 250 yr B.P. The pollen, plant macrofossils, and insect remains in the basal silt consist of boreal species inhabiting open environments, but not tundra. No modern analogue exists for the insect assemblage, which includes elements of boreal forest, tundra-forest, and western affinities. The transition from an unstable open environment to a stable coniferous forest is reflected by both plant and insect fossils and is interpreted as a successional rather than a climatic event. During this time of significant biologic change, the climate is inferred to have been relatively uniform, with temperatures similar to those presently existing in the boreal forest south of the tundra-forest transition zone. The geologic and ecologic succession at Norwood is generally similar to that presently associated with ice stagnation of the Klutlan Glacier in the Yukon Territory. Localized successional sequences similar to those at Norwood are conceived to have occurred repeatedly during the melting of the Laurentide ice, and thus the proposed model has potentially broad application to the interpretation of late-glacial sequences.
Benthonic Foraminiferal Faunal and Isotopic Data for the Postglacial Evolution of the Champlain Sea
Authors: Corliss Bruce H. , Hunt Allen S. , Keigwin Lloyd D. 
Published: December 2004

AbstractBenthonic foraminiferal faunal and isotopic data from Champlain Sea sediments (approximately 12,500 to 10,000 yr B.P. in age) in two piston cores from Lake Champlain provide a detailed, apparently continuous record of the evolution of the Champlain Sea. Cassidulina reniforme and Islandiella helenae are the dominant benthonic foraminifera during the initial phase of the Champlain Sea, and are replaced by Elphidium excavatum forma clavatum and Protelphidium orbiculare as the dominant species during the remainder of the sea's history. The oxygen-isotopic data show a gradual decrease in δ18O between approximately 12,500 and 10,900 yr B.P., followed by a more rapid decrease during the interval 10,900 to 10,000 yr B.P. The δ13C data have a similar trend as δ18O, with generally decreasing values up the section. The isotopic and faunal data suggest that nearly marine conditions were present in the initial plase of the Champlain Sea, followed by gradually decreasing salinities and increasing temperatures as the sea evolved. The beginning of the rapid isotopic decrease at approximately 10,900 yr B.P. marks the onset of the largest environmental change in the history of the Champlain Sea, probably reflecting a major pulse of meltwater from the Laurentide Ice Sheet.
Late Quaternary Environments and Biogeography in the Great Basin
Authors: Thompson R. S. , Mead J. I. 
Published: December 2004

AbstractPlant and animal remains found in packrat (Neotomaspp.) middens and cave fill from the eastern and southern Great Basin region reveal the presence of subalpine conifers and boreal mammals at relatively low elevations during the Late Wisconsin. Limber pine (Pinus flexilis) and bristlecone pine (P. longaeva) were important in the late Pleistocene plant communities throughout this region. Spruce (Piceacf.engelmannii) and common juniper (Juniperus communis) were present in some of the more northerly localities, and Douglas fir (Pseudotsuga menziesii) and white fir (Abies concolor) were present in southern and eastern localities. Single needle pinyon pine (Pinus monophylla), common across this region today, was apparently not present north of the Sheep Range of southern Nevada during the Late Wisconsin. Pikas (Ochotonacf.princeps), small boreal mammals present in only a few Great Basin mountain ranges today, were common throughout the region. Heather voles (Phenacomyscf.intermedius) have been found in two cave fill deposits in Nevada, though they are unknown in the Great Basin today. Limber and bristlecone pines are generally restricted to rocky substrates in modern subalpine habitats in the Great Basin, and this may also have been the case when these plants grew at lower elevations during the Late Wisconsin. Subalpine conifers were present on the rock outcrops sampled by the packrat middens, but shrub communities, perhaps dominated by sagebrush (Artemisiaspp.), may have been present on alluvial valley-bottom substrates. Forested habitats would thus have been isolated habitat islands, as they are today. Boreal small mammals, including pikas and heather voles, were able to colonize the Great Basin mountain ranges during the late Pleistocene. We suggest that these mammals were able to survive in the intervening valley-bottoms under a cool-summer climatic regime, and that continuous forest or woodland corridors were not necessary for migration.
The Timing of Late Pleistocene Mammalian Extinctions in North America
Authors: Meltzer David J. , Mead Jim I. 
Published: December 2004

AbstractMore than 375 14C dates from 150 fossil sites in North America have been analyzed to evaluate the question of extinction of Late Pleistocene megafauna. When critically evaluated, no 14C ages for any extinct Pleistocene genera are younger than 10,000 yr B.P.
Late Quaternary Insects of Rancho La Brea and McKittrick, California
Authors: Miller Scott E. 
Published: December 2004

AbstractAsphalt-impregnated sediments at Rancho La Brea (Los Angeles County) and McKittrick (Kern County) in California provide a rich Quaternary insect record. Ages of various sites at Rancho La Brea range from more than 40,00014C yr B.P. to modern. McKittrick insects studied by W. D. Pierce are not contemporaneous with the late Pleistocene vertebrate fauna, but are only about 700014C yr old. The major paleoecological groupings are: (1) ground dwellers, (2) aquatics. (3) scavengers, and (4) miscellaneous. Contrary to conclusions of earlier authors, most specimens represent modern species. Only two apparent terminal Pleistocene extinctions are recognized. both dung beetles (Scarabaeidae).
Late Pleistocene Paleoclimatology of the Central Equatorial Pacific: A Quantitative Record of Eolian and Carbonate Deposition
Authors: Chuey John M. , Rea David K. , Pisias Nicklas G. 
Published: December 2004

AbstractDetailed records of δ18O, δ13C, percentage and mass accumulation rate of CaCO3, and eolian percentage, mass accumulation rate, and grainsize generated for core RC11-210 from the equatorial Pacific reveal the timing of paleoclimatic events over the past 950,000 yr. The CaCO3 percentage record shows the standard Pacific correlation of high CaCO3 content with glacial periods, but displays a marked change of character about 490,000 yr ago with older stages showing much less variability. The carbonate mass flux record, however, does not show such a noticeable change. Sedimentation rates vary from about 0.5 to 3.0 cm/1000 yr and, during the past 490,000 yr, sections with enhanced sedimentation rates correspond to periods of high CaCO3 percentage. Eolian mass accumulation rates, an indication of the aridity of the source region, are usually higher during glacial times. Eolian grainsize, an indication of the intensity of atmospheric circulation, generally fluctuates at a higher frequency than the 100,000-yr glacial cycle. The mid-Brunhes climatic event centered at 300,000 yr ago appears as a 50,000-yr interval of low intensity and reduced variability of atmospheric circulation. Furthermore, the nature of this entire record changes then, with the younger portion indicating less variation in wind intensity than the older part of the record. The late Matuyama increase in amplitude of paleoclimatic signals begins 875,000 yr ago in the eolian record, 25,000 yr before the δ18O and CaCO3 percentage amplitude increases about 850,000 yr ago.
California Condor Associated with Spruce-Jack Pine Woodland in the Late Pleistocene of New York
Authors: Steadman David W. , Miller Norton G. 
Published: December 2004

AbstractA humerus, coracoid, and pedal phalanx of the California Condor,Gymnogyps californianus, were recovered from the Hiscock Site in western New York, in an inorganic stratum containing wood that is 11,000 radiocarbon years old. Associated vertebrates include mastodont, wapiti, and caribou. Pollen and plant macrofossils from the sediments indicate a spruce-jack pine woodland and a local, herb-dominated wetland community. Historic records (all from western North America) and previous late Pleistocene fossils of the California Condor are associated mainly with warm-temperate climates and floras. The New York fossils show that this bird was able to live in a colder climate and in a boreal, coniferous setting at a time when appropriate food (large mammal carrion) was available. The California Condor, which survives only in captivity, has suffered a greater reduction in geographical range than previously suspected. Much of this reduction in range probably occurred ca. 11,000 yr B.P. when the extinction many North American large mammals resulted in severely reduced availability of food for the California Condor and other large scavenging birds.
Palynology of Pleistocene Travertines from the Arava Valley, Israel
Authors: Weinstein-Evron Mina 
Published: December 2004

AbstractPollen samples from the Arava travertines, dated to oxygen isotope stages 5 and 7, show relatively high arboreal pollen levels. These spectra are probably a result of an expansion of the Mediterranean maquis in Transjordan, which indicates periods of wetter climatic conditions. These periods probably represent humid fluctuations within stages 5 and 7.
Climatic Implications of Alternating Clay and Carbonate Formation in Semiarid Soils of South-Central Montana
Authors: Reheis Marith C. 
Published: December 2004

AbstractEvidence for climatic change is found in petrographic thin sections from soils formed on glaciofluvial deposits of Rock Creek and the lower Clarks Fork, Montana. These soils, presently in a semiarid climate, range from late Pliocene to Holocene in age, and have undergone periodic fluctuations in soil moisture caused by climatic changes. In the lower parts of soil B horizons, accretion of illuvial layers of clay (argillans) occurs mainly during wet (glacial) climatic periods, whereas carbonate precipitates mainly during dry (interglacial) climatic periods. Thin-section studies of the argillan and carbonate layers show that: (1) post-Pinedale soils that have formed only in the present interglacial climate contain areas of secondary carbonate unrelated to argillans, (2) soils formed on outwash of successively older glaciations contain proportionately more alternating layers of argillans and carbonate, and (3) the maximum number and sequence of layers in a soil correspond to the number of local cycles of glacial-outwash deposition and subsequent stream incision that followed the beginning of soil formation. These cycles are inferred to correspond to local glacial-interglacial fluctuations. The correspondence between the microscopic record and the glacial-outwash record for Rock Creek suggests that some of the climatic changes seen in the marine oxygen-isotope record did not strongly affect the study area.
Paleohydrological Implications of Holocene Peatland Development in Northern Michigan
Authors: Miller Norton G. , Futyma Richard P. 
Published: December 2004

AbstractSediment, pollen, and plant macrofossil stratigraphies from two small oligotrophic Chamaedaphne-Sphagnum peatlands provide data about local hydrologic changes in northern Michigan during the Holocene. Gleason Bog started about 8000 yr B.P. as a shallow pond that supported rich fen vegetation. After it was partly filled with peat and sand (about 4000 yr B.P.), the vegetation changed to oligotrophic bog. At Gates Bog paludification starting about 3800 yr B.P. caused peat accumulation over sand without an initial pond phase. The onset of peat accumulation at both sites is attributed to a rise in the water table resulting from the onset of cool and moist late Holocene climates. The water table of Gleason Bog is linked to the water level of adjacent Douglas Lake, which may have undergone a simultaneous rise. The results emphasize the individuality of hydrological conditions and hydroseral development in northern Michigan peatlands.
Structural Position of the Pleistocene Gesher Benot Ya'aqov Site in the Dead Sea Rift Zone
Authors: Goren-Inbar N. , Belitzky S. 
Published: December 2004

AbstractNewly discovered outcrops of the middle Pleistocene Benot Ya'aqov Formation are strongly disturbed due to recent tectonic activity along the Dead Sea Rift. The lacustrine-fluviatile sediments of this formation comprise the littoral facies of a paleo-lake that occupied the adjacent Hula Basin. Acheulian artifacts, found embedded in the formation, have typical African characteristics. The geographical position of the site (the northern extension of the East African Red Sea Rift System) is important for understanding hominid diffusion from Africa to Eurasia.
Climate and Habitat Reconstruction Using Stable Carbon and Nitrogen Isotope Ratios of Collagen in Prehistoric Herbivore Teeth from Kenya
Authors: Ambrose Stanley H. , DeNiro Michael J. 
Published: December 2004

AbstractStable carbon and nitrogen isotope ratios have been determined for tooth collagen of 27 prehistoric herbivores from a rock shelter in the central Rift Valley of Kenya. Collagen samples whose isotope ratios were not altered by diagenesis were identified using several analytical methods. During the later Holocene, when the climate was as dry or drier than at present, the isotopic compositions of individual animals are similar to those of modern individuals of the same species. During the earlier Holocene, when the climate was wetter than at present, the δ15N and δ13C values are lower than those for their modern counterparts. When diagenetic factors can be discounted and adequate modern comparative data are available, stable isotope analysis of herbivore teeth and bones can be used to evaluate prehistoric climate and habitat conditions.
Ages of Travertine Deposits in Eastern Grand Canyon National Park, Arizona
Authors: Szabo Barney J. 
Published: December 2004

AbstractTravertine deposits in eastern Grand Canyon National Park, Arizona, are inferred to have formed under conditions of effective wetness that were greater than present. Uranium-series dating of 17 samples indicates that the deposits formed at about 15,000, 71,000, 111,000, 171,000, and 338,000 yr B.P. Intervals of travertine deposition are essentially contemporaneous with dated high paleolake levels, montane glacial maxima, and high paleowater-table levels from several Great Basin localities.
Stratigraphic and Tectonic Implications of Uranium-Series-Dated Coral Reefs from Uplifted Red Sea Islands
Authors: Hoang Chi Trach , Taviani Marco 
Published: December 2004

AbstractCorals from raised reef terraces on two islands (Zabargad and Northern Brother), considered to have been tectonically uplifted in connection with the Red Sea rifting, were dated with the U-series method. At Zabargad, there are at least three systems of raised coral reefs. The oldest terrace (>290,000–300,000 yr B.P.) is found at +10 to +15 m. A 200,000 yr B.P. high-sea stand is recorded by a terrace relict at +17 m on peridotite bedrock; the youngest system (125,000–138,000 yr B.P.) is very well represented around the island, with terraces at about +6 to +8 m. Corals from Northern Brother yield ages of 132,000–135,000 and 204,000 yr B.P. suggesting the existence of two systems of interglacial raised reefs. Both islands appear to have been tectonically quite stable since at least 125,000 yr B.P.
Mid-Wisconsinan Vertebrates and their Environment from January Cave, Alberta, Canada
Authors: Burns James A. 
Published: December 2004

AbstractJanuary Cave, in the Rocky Mountains of southwestern Alberta, has yielded vertebrate remains from a coprocenosis of mid-Wisconsinan-age. Taphonomic analysis indicates accumulation by raptors, mostly owls, and mammalian carnivores. The vertebrate record, together with pollen analysis, indicates that cool, dry conditions prevailed in an extensive tundra-like environment, with prairie elements in the valleys below. Thirty-four mammalian taxa have been recovered from January Cave. Today, some of these species (e.g.,Lemmus sibiricusandDicrostonyx torquatus) do not coexist with others (e.g.,Cynomyssp.,Mustela nigripes, Vulpes velox, andLagurus curtatus). Therefore, the January Cave local fauna represents a “nonanalog” mammalian community characteristic of the late Pleistocene. It suggests that the region enjoyed an equable climate, with reduced climatic extremes but still cool, further supporting a mid-Wisconsinan age estimate for the fauna. It is the first major, small vertebrate fauna of its age to be reported from Alberta.
The expression patterns of mRNA‐encoding stem cell factor, internal stem cell factor and c‐kit in the prepubertal and adult porcine ovary
Authors: Brankin V. , Hunter M. G. , Horan T. L. , Armstrong D. G. , Webb R. 
Published: December 2004

AbstractThe receptor, c‐kit, and its ligand, stem cell factor (SCF), are important regulators of ovarian follicle growth and development. The aim of this study was to identify the sites of expression of mRNA for c‐kit and SCF in prepubertal and mature (pregnant and non‐pregnant) animals. Ovaries were recovered from prepubertal animals, non‐pregnant sows and five sows at approximately 3 months of gestation. Ovine SCF and c‐kit DNA were cloned into plasmid vectors to produce RNA probes. Expression of mRNA encoding SCF and c‐kit were detected via in situ hybridization. Both mRNA were detected throughout ovaries from all animals. This study provides evidence that the growth‐factor complex is required throughout follicle development, and also for continued maintenance of the corpus luteum (CL) in the mature animal. SCF mRNA was localized to the granulosa cell layer and was also extensively expressed in endothelial tissue and throughout the CL. c‐kit mRNA was detected in the theca layer, oocytes and also in CL. In conclusion, expression of SCF and c‐kit mRNA in granulosa and theca cells, respectively, indicate an important interaction between somatic cells throughout follicle development and that in the mature animal, SCF and c‐kit potentially have a role in maintaining progesterone secretion by the CL. The observations of continued expression of SCF and c‐kit throughout development suggest that there may be differences in the role of this receptor–ligand complex between large mono‐ vs. poly ovulatory species, such as the pig.
Evaluation of cyclin D1 expression and its subcellular distribution in mouse tissues
Authors: De Falco Maria , Fedele Valentina , De Luca Luca , Penta Roberta , Cottone Giuliano , Cavallotti Ivan , Laforgia Vincenza , De Luca Antonio 
Published: December 2004

AbstractCyclin D1 is a key cell‐cycle regulatory protein required for the cell to progress through G1 to S phase. We have shown by Western blot analysis that cyclin D1 has a wide distribution in adult mouse tissues, with its level of expression being tissue‐dependent. Immunohistochemistry has also shown that cyclin D1 may be present in the cytoplasm, in the nucleus or in both these cell compartments: cytoplasmic staining was observed in both proliferating cells (e.g. kidney, intestine, stomach and salivary gland) and in the non‐dividing cells (the mature neurons of adult brain), while nuclear staining was seen in the neurons of the embryonic nervous system. Immunoelectron microscopy results indicate that, in tissues where cyclin D1 is present in both compartments (e.g. intestinal enterocytes), it may move via nuclear pores from the nucleus to the cytoplasm, and vice versa. The findings as a whole suggest that cyclin D1 may play multiple roles within specific tissues, probably by interacting with different substrates, and that its transit between nuclear and cytoplasmic compartments may help maintain cell homeostasis.
Chronic systemic hypoxia causes intra‐retinal angiogenesis
Authors: Shortt Alex J. , Howell Katherine , O'Brien Colm , McLoughlin Paul 
Published: December 2004

AbstractRetinal hypoxia occurs in many conditions that cause vascular disease in the eye and is an important stimulus to new vessel formation. However, the adult retina can also become hypoxic when there is systemic hypoxaemia such as occurs in chronic lung diseases, congenital cardiac disease and residence at high altitude. Little is known about the adaptive responses of the retinal vasculature in such circumstances. Previous research in the retinopathy of prematurity model may not apply to the adult tissue given the different mechanisms controlling angiogenesis in developing and mature circulations. We tested the hypothesis that chronic systemic hypoxia leads to angiogenesis in the adult retinal circulation, in the absence of pre‐existing vascular disease. Adult male Sprague–Dawley rats (n = 9) were exposed to a fraction of inspired oxygen of 0.10 for 2 weeks while control animals (n = 10) were exposed to room air. Stereological techniques were used to quantify the vascular volume, endothelial surface area and the total number of branch points of all blood vessels in the superficial retinal vascular plexus. The mean volume and endothelial surface area of these vessels were significantly greater in the hypoxic than in the control group. The mean number of blood vessel branch points was also significantly greater in the hypoxic group. Our findings demonstrate that chronic systemic hypoxia, in the absence of other pathological processes, causes angiogenesis in the adult rat retina and provide an in vivo model for investigating this important process in the adult retina, in particular pathways specific to this tissue.
THE GLOBAL‐LOCAL NEXUS: NGOs AND THE ARTICULATION OF SCALE
Authors: ARTS BAS 
Published: December 2004

ABSTRACT Non‐Governmental Organisations (NGOs), such as Greenpeace, World Wide Fund for Nature (WWF), Pax Christi, Oxfam and Amnesty International, have become effective political players at different governance levels: local, regional, national and international. In addition, they have contributed to the construction of multi‐level governance practices as well as to a re‐articulation of scale. They have done so, among others, by ‘thinking globally, acting locally’; re‐conceptualising local issues into global ones (and vice versa); bringing local interests to international negotiating tables; and building up ‘glocalised’ networks. In this paper, three cases to illustrate these claims will be presented: (a) the Biodiversity Convention; (b) the human rights regime; and (c) the Forest Stewardship Council (FSC). As a general conclusion, the effects of these non‐state, de‐territorialised and ‘glocalised’ practices on the role and authority of the nation state will be (shortly) assessed. It will be claimed that we do not observe a ‘general retreat of the state’, but issue‐specific re‐definitions of its role and authority.