bluuebunny/crossref_metadata_2025_split huggingface dataset:
Uranium-Series Ages of Travertines and Timing of the Last Glaciation in the Northern Yellowstone Area, Wyoming-Montana
Authors: Sturchio Neil C. , Pierce Kenneth L. , Murrell Michael T. , Sorey Michael L. 
Published: September 2002

AbstractUranium-series age determinations by mass spectrometric methods were done for travertines and associated carbonate veins related to clastic deposits of the last glaciation (Pinedale) in the northern Yellowstone area. Dramatic variations in the hydrologic head are inferred from variations in the elevation of travertine deposition with time and are consistent with the expected hydrologic effects of glaciation. We determine the following chronology of the Pinedale Glaciation, with the key assumption that travertine deposits (and associated carbonate veins) perched high above present thermal springs were deposited when glaciers filled the valley below these perched deposits: (1) the early Pinedale outlet glacier advanced well downvalley between 47,000 and 34,000 yr B.P.; (2) the outlet glacier receded to an interstadial position between 34,000 and 30,000 yr B.P.; (3) an extensive Pinedale ice advance occurred between 30,000 and 22,500 yr B.P.; (4) a major recession occurred between 22,500 and 19,500 yr B.P.; (5) a minor readvance (Deckard Flats) culminated after 19,500 yr B.P.; and (6) recession from the Deckard Flats position was completed before 15,500 yr B.P. This chronology is consistent with the general trend of climatic changes in the northern hemisphere as revealed by recent high-resolution ice-core records from the Greenland ice sheet.
Pedosedimentary Reconstruction of a Thick Loess-Paleosol Sequence near Lanzhou in North-Central China
Authors: Kemp Rob A. , Derbyshire Edward , Xingmin Meng , Fahu Chen , Baotian Pan 
Published: September 2002

AbstractA 38-m well section near Lanzhou at the semiarid western margin of the Loess Plateau, China, contained a continuous, high-resolution loess-paleosol sequence spanning the last 130,000 yr. Depth functions of micromorphological features, magnetic susceptibility, calcium carbonate, organic carbon, and median grain size provide the basis for pedosedimentary and associated paleoenvironmental reconstructions of three paleosol complexes (S1, Sm, and S0). Each pedosedimentary stage reflects the interaction of changing intensities of controlling monsoonal forces. Three periods of reduced dust inputs and enhanced pedogenic activity, notably bioturbation and weak leaching, can be identified from within the S1 pedocomplex. These "soil-forming intervals" were separated by phases of varying land surface instability characterized by arid dust deposition, semiarid accretionary pedogenesis, water reworking, and crust formation, or even freeze-thaw modification. The Sm pedocomplex represents an interval of relatively rapid dust accumulation with only minimal syndepositional modification and minor pedogenic alteration at ephemeral land surfaces. The S0 pedocomplex is clearly more pedogenically developed, although erosion, reworking, and mixing by water have partly homogenized the property depth functions.
The Last Interglaciation in Northeast Siberia
Authors: Lozhkin Anatoly V. , Anderson Patricia M. 
Published: September 2002

AbstractAlluvial, fluvial, and organic deposits of the last interglaciation are exposed along numerous river terraces in northeast Siberia. Although chronological control is often poor, the paleobotanical data suggest range extensions of up to 1000 km for the primary tree species. These data also indicate that boreal communities of the last interglaciation were similar to modern ones in composition, but their distributions were displaced significantly to the north-northwest. Inferences about climate of this period suggest that mean July temperatures were warmer by 4 to 8°C, and seasonal precipitation was slightly greater. Mean January temperatures may have been severely cooler than today (up to 12°C) along the Arctic coast, but similar or slightly warmer than present in other areas. The direction and magnitude of change in July temperatures agree with Atmospheric General Circulation Models, but the 126,000-year-B.P. model results also suggest trends opposite to the paleobotanical data, with simulated cooler winter temperatures and drier conditions than present during the climatic optimum.
Sea-Surface Temperatures and the History of Monsoon Upwelling in the Northwest Arabian Sea during the Last 500,000 Years
Authors: Emeis Kay-Christian , Anderson David M. , Doose Heidi , Kroon Dick , Schulz-Bull Detlef 
Published: September 2002

AbstractArabian Sea sediments record changes in the upwelling system off Arabia, which is driven by the monsoon circulation system over the NW Indian Ocean. In accordance with climate models, and differing from other large upwelling areas of the tropical ocean, a 500,000-yr record of productivity at ODP Site 723 shows consistently stronger upwelling during interglaciations than during glaciations. Sea-surface temperatures (SSTs) reconstructed from the alkenone unsaturation index (UK′37) are high (up to 27°C) during interglaciations and low (22-24°C) during glaciations, indicating a glacial-interglacial temperature change of >3°C in spite of the dampening effect of enhanced or weakened upwelling. The increased productivity is attributed to stronger monsoon winds during interglacial times relative to glacial times, whereas the difference in SSTs must be unrelated to upwelling and to the summer monsoon intensity. The winter (NE) monsoon was more effective in cooling the Arabian Sea during glaciations then it is now.
Aminostratigraphic Evaluation of Conflicting Age Estimates for the "Young Loess" of Hungary
Authors: Oches Eric A. , McCoy William D. 
Published: September 2002

AbstractAs part of a regional investigation of the aminostratigraphy of central European loess deposits, we have sampled and analyzed the amino acid composition of fossil gastropod shells from stratotype loess profiles at Mende, Basaharc, and Paks, plus the profile at Süttö, in an effort to correlate independently loess-paleosol formations of the "Young Loess" of Hungary with loess units elsewhere in the region. The measured extent of isoleucine epimerization in fossil gastropod shells preserved in loess sediments was used to evaluate the relative ages of stratigraphic units and correlate between discontinuous exposures. Based on amino acid epimerization ratios, we propose a new chronology for the standard "Young Loess" profile of Hungary. Amino acid geochronological data suggest that paleosol complexes MF, BD1 + 2, and BA formed during interglaciations, rather than interstades. Correlations are suggested with PK 2 + 3 (last interglaciation), PK 4 (penultimate interglaciation), and PK 5, respectively, from previously described Czech and Slovak localities.
Duration and Structure of the Past Four Interglaciations
Authors: Winograd Isaac J. , Landwehr Jurate M. , Ludwig Kenneth R. , Coplen Tyler B. , Riggs Alan C. 
Published: September 2002

AbstractReanalysis and additional dating of the Devils Hole δ18O paleotemperature record confirm that the last interglaciation in the Great Basin (the continental analog of marine isotopic substage 5e) lasted ∼22,000 yr, consistent with the Vostok paleotemperature record which suggests a duration of ∼19,000 yr for this event in Antarctica. The three preceding interglaciations in the Devils Hole record (analogs of marine isotopic substages 7e, 9c, and 11c) range from 20,000 to 26,000 yr in duration. A ∼20,000-yr duration for the last interglaciation is consistent with TIMS uranium-series dated sea-level high stands. Thus, the widely held view that interglaciations were of 11,000- to 13,000-yr duration and constituted only about 10% of mid-to-late Pleistocene climatic cycles needs reexamination. The warmest portion of each interglaciation in the Devils Hole time series is marked by a δ18O plateau, signifying apparent climatic stability for periods of 10,000- to 15,000-yr duration.
Tree-Ring δD as an Indicator of Asian Monsoon Intensity
Authors: Feng Xiahong , Cui Haiting , Tang Kuilian , Conkey Laura E. 
Published: September 2002

AbstractOxygen and hydrogen isotopic compositions of meteoric water are known to correlate with surface air temperature, except in tropical areas. This relationship has been described using a number of terms corresponding to specific observations, such as latitude, altitude and seasonal effects. However, these temperature effects do not seem to apply to precipitation in monsoonal areas of Asia. Questions have been raised as to whether the isotopic composition of meteoric water can be used to reconstruct paleomonsoon intensity. Tree rings of two modern spruce trees (Picea meyeri) and a 10,000-yr-old timber (Picea jezoensis) were analyzed for hydrogen isotopic composition. On average, the older tree is depleted in deuterium by 45‰ compared to the modern trees. We attribute this isotopic depletion to the strength of summer monsoons, which were more intense in the early Holocene than at present. Although this study is not definitive, it suggests that paleomonsoon intensity can be reconstructed by direct or proxy methods that yield the oxygen or hydrogen isotopic composition of meteoric water.
Geochemical Variations in Peoria Loess of Western Iowa Indicate Paleowinds of Midcontinental North America during Last Glaciation
Authors: Muhs Daniel R. , Bettis E. Arthur 
Published: September 2002

AbstractPeoria Loess deposited in western Iowa during the last glacial maximum (LGM) shows distinct geochemical and particle-size variations as a function of both depth and distance east of the Missouri River. Geochemical and particle-size data indicate that Peoria Loess in western Iowa probably had two sources: the Missouri River valley, and a source that lay to the west of the Missouri River. Both sources indicate that LGM paleowinds in western Iowa had a strong westerly component, similar to interpretations of previous workers. A compilation of loess studies in Iowa and elsewhere indicates that westerly winds were dominant during loess transport over much of the midcontinent south of the Laurentide ice sheet, which is not in agreement with paleowinds simulated by atmospheric general circulation models (AGCMs). AGCMs consistently generate a glacial anticyclone with easterly or northeasterly winds over the Laurentide ice sheet and the area to the south of it. Loess deposition in the midcontinent during the LGM may be a function of infrequent northwesterly winds that were unrelated to the presence of the glacial anticyclone.
Fish Remains from Homestead Cave and Lake Levels of the Past 13,000 Years in the Bonneville Basin
Authors: Broughton Jack M. , Madsen David B. , Quade Jay 
Published: September 2002

AbstractA late Quaternary ichthyofauna from Homestead Cave, Utah, provides a new source of information on lake history in the Bonneville basin. The fish, represented by 11 freshwater species, were accumulated between ∼11,200 and ∼100014C yr B.P. by scavenging owls. The87Sr/86Sr ratio of Lake Bonneville varied with its elevation;87Sr/86Sr values of fish from the lowest stratum of the cave suggest they grew in a lake near the terminal Pleistocene Gilbert shoreline. In the lowest deposits, a decrease in fish size and an increase in species tolerant of higher salinities or temperatures suggest multiple die-offs associated with declining lake levels. An initial, catastrophic, post-Provo die-off occurred at 11,300–11,20014C yr B.P. and was followed by at least one rebound or recolonization of fish populations, but fish were gone from Lake Bonneville sometime before ∼10,40014C yr B.P. This evidence is inconsistent with previous inferences of a near desiccation of Lake Bonneville between 13,000 and 12,00014C yr B.P. Peaks inGila atrariafrequencies in the upper strata suggest the Great Salt Lake had highstands at ∼3400 and ∼100014C yr B.P.
Late Quaternary Vegetation Dynamics in the Southern Amazon Basin Inferred from Carbon Isotopes in Soil Organic Matter
Authors: de Freitas Hermes Augusto , Pessenda Luiz Carlos Ruiz , Aravena Ramon , Gouveia Susy Ely Marques , de Souza Ribeiro Adauto , Boulet René 
Published: September 2002

AbstractCarbon isotopes of soil organic matter (SOM) were used to evaluate and establish the chronology of the vegetation dynamics of an ecosystem presently composed of savannas surrounded by forests. The study was carried out on a 200-km transect along highway BR 319, on the border of Amazonas and Rondônia states, in southern Amazon, Brazil. Large ranges in δ13C values were observed in SOM collected from profiles in the savanna (−27 to −14‰) and forest regions (−26 to −19‰), reflecting changing distribution of13C-depleted C3forest and13C-enriched C4savanna vegetation in response to climate change. These results indicate that from about 17,000 to 900014C yr B.P., the study area was covered by forest vegetation. Between approximately 9000 and 300014C yr B.P., savanna vegetation expanded at the expense of the forest. Although the expansion of savanna did not occur with the same intensity along the study transect, this process was very clearly registered by13C-enrichment in the SOM. Since 300014C yr B.P., the carbon isotope data suggest that forested regions have expanded. This study adds to the mounting evidence that extensive forested areas existed in the Amazon during the last glaciation and that savanna vegetation expanded in response to warm and dry conditions during the early to middle Holocene.
Late Pleistocene Glaciation of the Kosciuszko Massif, Snowy Mountains, Australia
Authors: Barrows Timothy T. , Stone John O. , Fifield L. Keith , Cresswell Richard G. 
Published: September 2002

AbstractLate Pleistocene glaciation of the Australian mainland was restricted to a small area of the southeastern highlands. Geomorphic mapping of the area and exposure dating using thein situproduced cosmogenic isotope10Be provides evidence for at least two distinct glaciations. The Early Kosciuszko glaciation consisted of a single glacier advance before 59,300 ± 5400 years ago (Snowy River Advance). The Late Kosciuszko glaciation comprised three glacier advances 32,000 ± 2500 (Headley Tarn Advance), 19,100 ± 1600 (Blue Lake Advance), and 16,800 ± 1400 years ago (Mt. Twynam Advance). The Early Kosciuszko glaciation was the most extensive and the Late Kosciuszko advances were progressively less extensive. These periods of glaciation in the highlands correspond to episodes of periglacial activity and peaks in lake levels and river discharge at lower elevations in southeastern Australia. Glacier advances on the Kosciuszko Massif correlate with advances in Tasmania, South America, and New Zealand and are broadly representative of hemispheric climate changes during the last glacial cycle.
Rates of Deglaciation during the Last Glaciation and Holocene in the Cordillera Vilcanota-Quelccaya Ice Cap Region, Southeastern Perú
Authors: Mark Bryan G. , Seltzer Geoffrey O. , Rodbell Donald T. , Goodman Adam Y. 
Published: September 2002

AbstractMoraine chronology is combined with digital topography to model deglacial rates of paleoglacier volumes in both the Huancané Valley on the west side of the Quelccaya Ice Cap and the Upismayo Valley on the northwest side of the Cordillera Vilcanota. The fastest rates of deglaciation (39×10−5 to 114×10−5 km3 yr−1 and 112×10−5 to 247×10−5 km3 yr−1 for each valley, respectively) were calculated for the most recent paleoglaciers, corresponding to the last few centuries. These results are consistent with observations in the Venezuelan Andes showing high rates of deglaciation since the Little Ice Age. These rates also fall within the range of 20th century rates of deglaciation measured on the Quelccaya Ice Cap (29×10−5 to 220×10−5 km3 yr−1, Brecher and Thompson, 1993; Thompson, 2000). These results imply that rates of deglaciation may fluctuate significantly over time and that high rates of deglaciation may not be exclusive to the late 20th century. Equilibrium line altitude (ELA) depressions for the ice volumes of the last glaciation modeled here were computed as 230 m for the Quelccaya Ice Cap and 170 m for the Cordillera Vilcanota. Maximum ELA depressions are lower than previously published: <500 m for the Cordillera Vilcanota and <400 m for the Quelccaya Ice Cap. These lower values could imply a topographic control over paleoglacier extent.
A Late Pleistocene Tephra Layer in the Southern Great Basin and Colorado Plateau Derived from Mono Craters, California
Authors: Madsen David B. , Sarna-Wojcicki Andrei M. , Thompson Robert S. 
Published: September 2002

AbstractA newly identified tephra in stratified deposits in southwestern Utah, dated ∼14,000 14C yr B.P., may aid in correlating late Pleistocene deposits across parts of the southern Great Basin and west-central Colorado Plateau. Geochemical analyses of the ash suggest the tephra originated from Mono Craters, California, and most probably correlates with Wilson Creek ash #3. Because the ash is 2 mm thick ∼550 km from its source, the event may have been larger than others correlated to Mono Craters eruptions.
Induction of mitochondrial permeability transition by auranofin, a Gold(I)‐phosphine derivative
Authors: Rigobello Maria Pia , Scutari Guido , Boscolo Rita , Bindoli Alberto 
Published: September 2002

Gold(I)‐thiolate drugs are compounds that specifically interact with thiol and/or selenol groups and are essentially utilized in the treatment of rheumatoid arthritis.
Considering the importance of thiol groups in regulating mitochondrial membrane permeability, the effects of auranofin (S‐triethylphosphinegold(I)‐2,3,4,6‐tetra‐O‐acetyl‐1‐thio‐β‐D‐glucopyranoside), a second‐generation gold drug, were studied on mitochondria isolated from rat liver.
Auranofin, at submicromolar concentrations, was able to induce the mitochondrial membrane permeability transition observed as swelling and loss of membrane potential. Both events are completely inhibited by cyclosporin A, the specific inhibitor of mitochondrial permeability transition. Calcium ions and energization by succinate are required for the occurrence of permeability transition.
By interacting with the active site selenol group, auranofin results as an extremely potent inhibitor of mitochondrial thioredoxin reductase, both isolated and in its mitochondrial environment.
It is concluded that auranofin, in the presence of calcium ions, is a highly efficient inducer of mitochondrial membrane permeability transition, potentially referable to its inhibition of mitochondrial thioredoxin reductase.

British Journal of Pharmacology (2002) 136, 1162–1168. doi:10.1038/sj.bjp.0704823
Rapid neuromodulation by cortisol in the rat paraventricular nucleus: an in vitro study
Authors: Zaki Abu , Barrett‐Jolley R 
Published: September 2002

We have used a range of in vitro electrophysiological techniques to investigate the mechanism of rapid cortisol neuromodulation of parvocellular neurones in the rat paraventricular nucleus.
In our study, we found that cortisol (10 μM) increased spontaneous action–current firing frequency to 193%. This effect was insensitive to the glucocorticoid intracellular‐receptor antagonist mifepristone.
Cortisol (0.1–10 μM) had no detectable effects on whole‐cell GABA current amplitudes, or GABAA single‐channel kinetics.
Cortisol (10 μM) inhibited whole‐cell potassium currents in parvocellular neurones by shifting the steady‐state activation curve by 14 mV to the right.
Additionally, in a cell line expressing both the glucocorticoid intracellular receptor and recombinant, fast inactivating potassium channels (hKv1.3), cortisol (1 and 10 μM) inhibited potassium currents by shifting their steady‐state activation curves to the right by 12 mV (10 μM cortisol). This effect was also insensitive to the cortisol antagonist, mifepristone.
These data suggest that inhibition of voltage‐gated potassium channels may contribute to the rapid neuromodulatory effects of cortisol, possibly by direct interaction with the ion channel itself.

British Journal of Pharmacology (2002) 137, 87–97. doi:10.1038/sj.bjp.0704832
A Comparison between Human and Machine Labelling of Image Regions
Authors: Clark Angus A , Troscianko Tom , Campbell Neill W , Thomas Barry T 
Published: September 2002

In previous work (Campbell et al, 1997 Pattern Recognition30 555–563) a vision system was developed which is capable of classifying objects in outdoor scenes. The approach involves segmenting the image into regions, obtaining a feature-based description of each region, and then passing this description on to an artificial neural network (ANN) which has been trained to label the region with one of eleven possible object types. The question addressed here is: how important is each of these features to overall performance, both in human and machine vision? A set of experiments was conducted in which human subjects were trained in the same labelling task as the ANN. The stimuli, each depicting a single image region, were generated from a large database of urban and rural images. The subjects were then tested on both intact and degraded stimuli. The results suggest that certain features are particularly influential in mediating overall labelling performance. An equivalent experiment was carried out with the ANN. A method is presented which allows individual features to be corrupted in such a way as to simulate the loss of certain forms of visual information. The results, which are broadly similar to those found in the previous experiment, imply that the ANN can provide a useful model of human image region labelling. It is anticipated that the methodology, which draws on both computational and psychophysical techniques, will be of use to other areas of investigation.
Site‐specific DNA cleavage of synthetic NarL sites by an engineered Escherichia coli NarL protein–1,10‐phenanthroline cleaving agent
Authors: Xiao Gaoping , Cole Daniel L. , Gunsalus Robert P. , Sigman David S. , Chen Chi‐Hong B. 
Published: September 2002

AbstractThe NarL response regulatory protein of Escherichia coli has been engineered by covalent modification with 1,10‐phenanthroline (OP) to create a set of site‐specific DNA‐cleaving agents. This was accomplished by introducing single cysteine amino acid replacements at selected locations within the carboxy‐terminal DNA‐binding domain in or nearby the helix 8 to helix 9 region of the NarL protein using site‐directed mutagenesis. Of 18 modified NarL‐OP proteins made, 13 retained the ability to bind DNA as evidenced by gel mobility assays, whereas 10 of the 1,10‐phenanthroline‐modified proteins also exhibited specific cleavage activity for a synthetic NarL recognition sequence. These DNA‐cleaving agents were divided into two groups based on the location of the cleavage sites. The first class set cleaved the DNA nearby the center of a synthetic 7–2–7 sequence composed of two NarL heptamer sites separated by a 2‐bp spacer element. The second class cut the DNA at the periphery of the 7–2–7 sequence. The cleavage data are consistent with the ability of two NarL monomers to recognize and bind to the DNA in a head‐to‐head orientation. A second set of DNA‐cleaving agents was constructed using the carboxy‐terminal domain of NarL called NarLC. Similar cleavage patterns were observed whether full‐length NarL or NarLC was used. The availability of 1,10‐phenanthroline‐modified NarL and NarLC proteins opens up the possibility to explore the position, orientation, and number of NarL recognition sites at E. coli promoters predicted to contain multiple and complex arrangements of NarL‐binding sites.