bluuebunny/crossref_metadata_2025 huggingface dataset:
The Sulphur Spring Stage and its Place in New World Prehistory
Authors: Waters Michael R.
Published: December 2004

Radiocarbon dates from archaeological sites in Whitewater Draw, Arizona, place the Sulphur Spring stage of the Cochise Culture between 8000 and 10,000 yr B.P., and possibly back to 10,400 yr B.P. Geoarchaeological investigations of Whitewater Draw do not substantiate an earlier claim that Sulphur Spring stage ground stone artifacts are associated with extinct megafauna, nor the hypothesis that Sulphur Spring stage artifacts are specialized plant processing tools of the Clovis Culture.
Pattern and Forcing of Northern Hemisphere Glacier Variations During the Last Millennium
Authors: Porter Stephen C.
Published: December 2004

Time series depicting mountain glacier fluctuations in the Alps display generally similar patterns over the last two centuries, as do chronologies of glacier variations for the same interval from elsewhere in the Northern Hemisphere. Episodes of glacier advance consistently are associated with intervals of high average volcanic aerosol production, as inferred from acidity variations in a Greenland ice core. Advances occur whenever acidity levels rise sharply from background values to reach concentrations ≥1.2 μequiv H+/kg above background. A phase lag of about 10–15 yr, equivalent to reported response lags of Alpine glacier termini, separates the beginning of acidity increases from the beginning of subsequent ice advances. A similar relationship, but based on limited and less-reliable historical data and on lichenometric ages, is found for the preceding 2 centuries. Calibrated radiocarbon dates related to advances of non-calving and non-surging glaciers during the earlier part of the Little Ice Age display a comparable consistent pattern. An interval of reduced acidity values between about 1090 and 1230 A.D. correlates with a time of inferred glacier contraction during the Medieval Optimum. The observed close relation between Noothern Hemisphere glacier fluctuations and variations in Greenland ice-core acidity suggests that sulfur-rich aerosols generated by volcanic eruptions are a primary forcing mechanism of glacier fluctuations, and therefore of climate, on a decadal scale. The amount of surface cooling attributable to individual large eruptions or to episodes of eruptions is simlar to the probable average temperature reduction during culminations of Little Ice Age alacier advances (ca. 0.5°–1.2°C), as inferred from depression of equilibrium-line altitudes.
Growth of Ibyuk Pingo, Western Arctic Coast, Canada, and Some Implications for Environmental Reconstructions
Authors: Mackay J. Ross
Published: December 2004

Ibyuk Pingo, which is 49 m high and 300 m in basal diameter, is one of the largest pingos in the world. Precise surveys carried out for the 1973 to 1983 period indicate that the lower half of the pingo, below a height of 25 m, shows no perceptible growth. From 25 m to the top, the growth steadily increases to a maximum of 2.3 cm/yr at the summit. The source of growth is believed to lie at a depth of about 65 m below the highest peak. Evidence based upon the depth of permafrost near the pingo, radiocarbon dating of wood in the pingo overburden, heat conduction theory, and the measured growth rate suggests an age of about 1300 ± 200 yr. Ibyuk Pingo is in an unstable state and collapse could be initiated by further slumping, a thermal disturbance to the crater, or erosion along a radial dilation crack. A study of the potential collapse pattern of Ibyuk Pingo suggests a number of criteria that might be employed in the environmental reconstruction of large circular features that might be identified as collapsed pingo remnants.
Changing Late Holocene Flooding Frequencies on the Columbia River, Washington
Authors: Chatters James C. , Hoover Karin A.
Published: December 2004

Data from prehistoric fluvial deposits can be used to extend the flood history of a river valley beyond historical records, thus increasing our understanding of variability in large, low-frequency flood events and providing a valuable means for paleoenvironmental reconstruction. We have applied this form of analysis to fluvial deposits from an archaeological site on the upper Columbia River in the state of Washington dating from 120 A.D.∗ to 1948 A.D. It was our expectation that, had flood frequencies remained constant, sedimentation event frequency would conform to an exponential function derived from the Wolman and Leopold model of vertical floodplain accretion. Our findings deviate from this model, showing that flood frequencies comparable to those of the twentieth century existed prior to 1020 A.D.∗ and after 1390 A.D.∗ Large floods were three to four times more common during the intervening centuries. On the basis of field evidence, we can rule out changing channel geometry, leaving climatic conditions as the most probable factors controlling this variation in flood frequency.
Holocene Evolution of the Northeastern Corner of the Nile Delta
Authors: Sneh A. , Weissbrod T. , Ehrlich A. , Horowitz A. , Moshkovitz S. , Rosenfeld A.
Published: December 2004

The constructive phase of the modern Nile Delta, as manifested in a 48-m section drilled east of the Suez Canal, commenced in very early Holocene times. Sands rich in marine fauna were deposited in the littoral zone and the shoreline was more than 20 km landward of its present-day position. Subsequently, clays and silts were dumped from the Nile distributaries and the marine faunal spectrum became very limited and brackish. Later in early and middle Holocene times the sediments deposited were rich in freshwater, delta-plain diatoms and pollen and in allochthonous fern spores from the tropics, indicating proximity of a distributary mouth. The middle part of the section (22.5-17.5 m) is very poor in faunal and floral remains; pollen grains from sabkha vegetation are abundant. The environment, which seems lagoonal and slightly hypersaline, is related to the sea regression in middle Holocene times. Euryhaline pelecypods, dating from about 3000 yr B.P., are abundant around the 8-m depth. Upward, there is an increase in pollen grains from sabkhas; the section is poor in diatoms and those present are mostly euryhaline and lagoonal. Allochthonous spores derived from the nearby Pelusiac Branch are abundant. Between 3000 and 2000 yr B.P. the constructive phase of the modern delta terminated and winnowed sands began accreting in front of the delta plain.
Reconstruction of Holocene Changes in Alpine Vegetation and Climate in the Maligne Range, Jasper National Park, Alberta
Authors: Luckman B. H. , Kearney M. S.
Published: December 2004

Pollen, macrofossil (logs and needles), and oxygen-isotope data from tree rings are presented for three alpine bog sites in the Maligne Range of the Canadian Rockies. Organic sedimentation at the Watchtower site began prior to ca. 9500 14C yr B.P. and by 8770 yr B.P. timberlines were at least 100 m above present levels. The two pollen records are dominated by Pinus and subsequent changes in timberlines are inferred from pollen-ratio data (Abies/Pinus) and from macrofossils. The recovered records indicate two periods of high Hypsithermal timberlines ca. 8800-7500 and 7200-5200 yr B.P. separated by a short interval ca. 7300–7400 yr B.P. when timberline approached modern levels. After ca. 4500 yr B.P. timberlines have been similar to or lower than present, reaching minimum values in the last 500 yr. δ18O determinations from the α-cellulose of samples of 5 or 10 annual rings cut from contemporary Picea englemannii at timberline show strong correlations with mean annual temperatures at Jasper. Isotopic determinations from Hypsithermal-age logs recovered from sites above present timberline indicate mean annual temperatures were at least 0.5°C warmer ca. 8060 and 8770 yr B.P. than at present at the Watchtower site. Data from logs at the Maligne Pass site suggest that temperatures were about 1.2° and 1.6°C warmer ca. 6000 and 5300 yr B.P. Estimates of temperature from the pollen-ratio data are more conservative and suggest maximum differences of ca. 1.0°C in July temperatures over the last 8000 yr.
Stegomastodon Associated With Mammuthus in Arizona During the Quaternary
Authors: Madden Cary T.
Published: December 2004

The gomphothere, Stegomastodon, is the most morphologically progressive non-elephant proboscidean in North America. Prior to the appearance of mammoths during the earliest Pleistocene, stegomastodonts held niches later occupied by those elephants. Two proboscidean specimens from near Taylor, Arizona, show that elephant-like Stegomastodon coexisted with Mammuthus in the southwestern United States during the Quaternary. Other associations of Stegomastodon and Mammuthus are known from the early and middle Pleistocene of Texas and the early Pleistocene of Nebraska. The mammoth from the Taylor locality is the oldest known from Arizona.
Light Rings in Subarctic Conifers as a Dendrochronological Tool
Authors: Filion Louise , Payette Serge , Gauthier Line , Boutin Yves
Published: December 2004

Light rings are characterized by one or a very few latewood-cell layers, an indication of shortened growing seasons, and are particularly frequent in black spruce (Picea mariana (Mill.) BSP) at the treeline in Québec. The construction of a light-ring chronology spanning the period AD 1398–1982 showed that the highest frequency (>25%) of light rings among 160 trees and krummholz occurred in 1593, 1620, 1634, 1784, 1816, 1817, 1853, 1969, and 1972. These diagnostic rings be a useful cross-dating tool for dendroecologists working with living and dead krummholz with a low-growth variability. About two-thirds of the 65 light-ring years coincide with years (or triads) of major volcanic eruptions. The climatic conditions (low temperature) occurring at the end of the growing season, in part induced by the climatic effect of volcanism, seem to initiate light rings.
An Analysis of the Chronology of Late Pleistocene Mammalian Extinctions in North America
Authors: Grayson Donald K.
Published: December 2004

Some 35 genera of mammals became extinct in North America as the Pleistocene came to an end. Current attempts to explain those extinctions generally assume that all of the losses took place between 12,000 and 10,000 yr B.P., even though 13 of the 35 genera lack radiocarbon dates of reasonable validity that would place them in this 2000-yr period. Analyses of the structure of the radiocarbon chronology available for the extinct taxa suggest that some may lack terminal Wisconsin dates simply because they are so poorly represented in the paleontological record. These analyses also suggest, however, that the population numbers of many genera that became extinct toward the end of the Pleistocene may have significantly dwindled by 12,000 yr B.P., and that many of the genera that have yet to be dated to terminal Wisconsin times may not have survived beyond 12,000 yr B.P. If this is the case, current explanations of the extinctions are in need of extensive modification.
Suggested Terminology for Quaternary Dating Methods
Authors: Colman Steven M. , Pierce Kenneth L. , Birkeland Peter W.
Published: December 2004

Classification of Quaternary dating methods should be based on the level of quantitative information and the degree of confidence contained in the age estimates produced by the dating methods. We recommend the use of the terms numerical-age, calibrated-age, relative-age, and correlated-age to describe these levels. We also classify dating methods by type into sideral, isotopic, radiogenic, chemical and biological, geomorphic, and correlation methods. The use of “absolute” is inappropriate for most dating methods, and should be replaced by “numerical.” The use of “date” should be minimized in favor of “age” or “age estimate.” We recommend use of the abbreviations ka and Ma for most ages; calender dates can be used where appropriate and yr B.P. can be used for radiocarbon ages.
More on Deep Glacial Erosion by Continental Ice Sheets and Their Tongues of Distributary Ice
Authors: White William A.
Published: December 2004

High latitude intracontinental seaways occupy great troughs carved by broad tongues of inland ice as it debouched to deep marine water. Such troughs occur in glaciated coasts, but not in stable, nonglaciated ones. Where ice flowed along the walls of troughs whose adjacent uplands held local glaciers, the walls simulate alpine troughs with faceted spurs and submarine hanging tributary valleys. Where uplands were not glaciated, trough walls are unbreached. Where ice flowed across them, coasts are digitate in low relief. In the northeastern sector of the Laurentide Ice Sheet, large glacial grooves converge toward the Gulf of Boothia-Prince Regent Inlet-Lancaster Sound avenue of egress to open sea, suggesting that it was an exit for inland ice which shaped it to its present form. The subduction Pacific coast of the Americas is mostly harborless in nonglaciated latitudes, but in southern Chile and British Columbia it is dissected. A circular gravity high 2800 km across is concentric with the area covered by the Laurentide Ice Sheet. Abyssal glacial silts are voluminous enough to account for an average of 100–150 m of erosion over the area covered by the Laurentide Ice Sheet.
Bounds on the Holocene Slip Rate of the Haiyuan Fault, North-Central China
Authors: Peizhen Zhang , Molnar Peter , Burchfiel B. C. , Royden L. , Yipeng Wang , Qidong Deng , Fangmin Song , Weiqi Zhang , Decheng Jiao
Published: December 2004

We measured the offsets of six stream valleys, of 30 to 90 m, along the northwest-southeast trending, left-lateral Haiyuan strike-slip fault, in north-central China. Minimum ages of these offsets were determined to estimate lower bounds for the Holocene slip rate. The most reliable bounds are 7.6 ± 1.0 and 6.7 ± 1.0 mm/yr, with three others that are smaller (3.4 ± 0.7, 3.5 ± 0.9, and 4.1 ± 0.4 mm/yr) and one large value (16.4 ± 5.9 mm/yr) that we doubt. Thus, the average Holocene slip rate of the Haiyuan fault is larger than 6 mm/yr and probably exceeds 7 mm/yr. If the average slip rate of 5 to 10 mm/yr for the Quaternary Period is applicable to the Holocene Epoch, the average rate is 8 ± 2 mm/yr.
Fluvial Sedimentation in Response to Postglacial Uplift and Environmental Change, Missisquoi River, Vermont
Authors: Brakenridge G. Robert , Thomas Peter A. , Conkey Laura E. , Schiferle Jane C.
Published: December 2004

Three lithologically distinct alluvial units of Holocene age can be distinguished along trenched cross sections of the Missisquoi valley bottom. The oldest is of early Holocene age, and the associated floodplain had aggraded to nearly its present level by 8000 14C yr B.P. At that time, early Archaic projectile points were deposited in a fire hearth 50 cm below the surface. Abandonment of this floodplain was followed by the development of an A-E-Bt soil profile. Accumulation of a younger floodplain had begun by 6400 14C yr B.P. and local sedimentation persisted to ca. 500 14C yr B.P., as indicated by radiocarbon dates of buried woody debris (including large logs) and of charcoal. Alluvium of the modern floodplain began accreting after A.D. 1860 and contains machine-cut square nails, whiteware ceramics, and coal clinker. Previous locations of the river channel can be reconstructed from relict surfaces marked by paleosols, the preserved depositional stratigraphy, and the radiocarbon samples. Immediately after regression of the Champlain Sea from this part of the valley, and before 8000 14C yr B.P., the river incised late Fleistocene marine silts and clays at an average rate of at least 1 m/100 yr. After the interval of downcutting, episodic lateral migration became the dominant process, with the rate varying between 0 and 4 m/100 yr. The early Holocene incision was most likely a lagged response to postglacial crustal rebound, whereas strong soil development and floodplain stability between 8000 and 6400 14C yr B.P. may reflect an independently documented warmer, and perhaps drier, climate in New England at this time. Finally, the post-A.D. 1860 period of active floodplain sedimentation may have been a response to timber clear-cutting, row crop agriculture, and cattle and sheep grazing in the watershed.
Postglacial Response of a Stream in Central Iowa to Changes in Climate and Drainage Basin Factors
Authors: Van Nest Julieann , Bettis E. Arthur
Published: December 2004

Postglacial geomorphic development of the Buchanan Drainage, a small tributary to the South Skunk River, is reconstructed by documenting relationships among four allostratigraphic units and 17 radiocarbon dates. Formation and headward expansion of the valley was both episodic and time-transgressive. Response to downstream conditions in the South Skunk River largely controlled the early formation of the basin. Downcutting through Pleistocene deposits produced a gravelly lag deposit that was buried by alluvium in the downstream portion of the valley during the early Holocene (10,500–7700 yr B.P.). Lag deposits formed in a similar manner continued to develop in the upper portion of the drainageway into the late Holocene (3000-2000 yr B.P.). Episodes of aggradation during the middle Holocene (7700-6300 yr B.P.) and late Holocene (3000-2000 yr B.P.) were separated by a period of soil formation. Holocene geomorphic events in the drainageway coincide with some vegetational and climatic changes as documented in upland pollen sequences from central Iowa. Analysis of plant macrofossil assemblages recovered from alluvium indicates that during the middle Holocene forest contracted and prairie expanded into the uplands within the basin. Vegetational changes within the basin apparently had only minor influence on rates of hillslope erosion, and the widely accepted relationship between prairie (versus forest) vegetative cover and increased rates of hillslope erosion did not hold. Instead, greater amounts of erosion occurred under forested conditions when local water tables were higher and seepage erosion was more effective.
Climatic transfer function from quaternary molluscs in European loess deposits
Authors: Rousseau Denis-Didier
Published: December 2004

Correspondence and multiple regression analysis of terrestrial molluscs in the loess sections of Achenheim (Alsace, France) has permitted the reconstruction of climatic variations during the last three glacial-interglacial cycles back to 339,000 yr B.P. The sequence has been dated according to the SPECMAP chronology of Imbrie et al. (1984) and the fossil faunas have been calibrated in relation to recent assemblages sampled in defined ecological conditions in Sweden and France. Transfer functions that relate the abundances of different species to climate allow the reconstruction of temperature and precipitation. Estimates for the coldest (February) and warmest (August) months in present-day Alsace were obtained and variations in temperature between −13° and 2°C in winter and 10° and 17°C in summer were determined. These results are consistent with those yielded by transfer functions using other continental fossils. Estimates differ for past precipitation. Summer precipitation is always less than present (with values between 50 and 78 mm, while modern August values are 76 mm higher). Winter estimates are always higher than the present mean (between 76 and 33 mm, while the recent February value is 34 mm). Comparisons between cycles show that the climatic patterns described for one cycle cannot be strictly applied to the others. Comparisons have been made with the pollen stratigraphy of La Grande Pile, the nearest quantified sequence to Achenheim, and with some Atlantic cores in order to study the magnitude of deviations from modern mean values of the climatic parameters.
Stratigraphy of the Colorado Creek Mammoth Locality, Alaska
Authors: Thorson Robert M. , Guthrie R. Dale
Published: December 2004

The Colorado Creek mammoth locality in west-central Alaska contains the remains of two mammoths that were scavenged by carnivores. Sedimentologic interpretations of the reworked eolian deposits surrounding the bones, supplemented by 10 radiocarbon dates, indicate that the lower and upper mammoths died and were buried within separate, but superimposed, thaw gullies about 23,000 and 16,000 yr ago, respectively. From our results, we propose a polycyclic taphonomic model for thaw gullies governed largely by slope aspect, rather than regional climate, and in which mixing between faunal horizons is more likely than not. Variations in the rate of silt influx and the position of the permafrost table provide a paleoclimatic proxy record that can be correlated to other records in eastern Beringia.
Implications of Late Quaternary Mammalian Fauna from Lukenya Hill (South-Central Kenya) for Paleoenvironmental Change and Faunal Extinctions
Authors: Marean Curtis W.
Published: December 2004

Late Quaternary paleoenvironmental data for East Africa are derived primarily from montane sources and thus we know little about the changing composition of East African savannas. Four archaeological sites at Lukenya Hill in the savanna of the Athi-Kapiti Plains of Kenya that date to the last 40,000 yr preserve a large mammalian fauna. The prehistoric hunters concentrated on migratory ungulates and virtually ignored the resident inselberg ungulates throughout the occupation. Faunas of the last glacial maximum are dominated by an extinct small alcelaphine antelope. Arid-adapted ungulates are present that are regionally absent historically, and Pelorovis is present as well. The small alcelaphine and arid-adapted ungulates are absent in the Holocene deposits. This suggests that there was an expansion of dry savannas during the last glacial maximum. The last glacial maximum aridity, combined with a lack of pastoral-set fires, would have resulted in a vegetative mosaic distinct from the present. Dry woody growth and dry and/or tall grass, all of which are poor forage for ungulates, would have been common where seasonally moist short grasslands are presently extant. These conditions favored the large-bodied, highly hypsodont species in Africa that became extinct with the onset of wet conditions during the early Holocene.
Is Equality Good Medicine? Determinants of Life Expectancy in Industrialized Democracies
Authors: CREPAZ MARKUS M. L. , CREPAZ NICOLE
Published: December 2004

The association between income inequality which creates psycho-social stress and longevity is of a curvilinear, concave nature. Low levels of income inequality are connected with shorter life expectancy. As inequality increases so does life expectancy until a point is reached where further increases in inequality lead to decreases in life expectancy. This finding is consistent with general theories of the effects of stress on performance as found in the fields of social psychology and sports medicine. In addition, we found that the life expectancy of populations is driven by factors such as perceived political control, the generosity of the welfare state, life-styles, GDP per capita and the poverty rate. Independently of which measure of income inequality was used or which statistical method was applied, these findings remained robust even when a number of alternative explanations were controlled for.
Measures Necessary to Ensure: The ICJ's Provisional Measures Order in Avena and Other Mexican Nationals
Authors: SLOANE ROBERT D.
Published: December 2004

This article analyzes the provisional measures order of the International Court of Justice (ICJ) in Avena and Other Mexican Nationals, the first provisional measures order issued by the ICJ after its decision in LaGrand holding that such orders have binding effect. After reviewing the background to Mexico's action, the article focuses on Avena's place in the Court's provisional measures jurisprudence, its international legal significance, its potential effects, if any, on the ICJ's perceived institutional legitimacy and authority, and its legal and political consequences for the United States. In particular, the article examines the domestic legal implications of the Court's order for the United States in the context of developing international norms on capital punishment and the due process standards governing its implementation in states that continue to practise it.
Oil's Well that Ends Well? Critical Comments on the Merits Judgement in the Oil Platforms Case
Authors: KAMMERHOFER JÖRG
Published: December 2004

The recent judgement on the merits in the Oil Platforms case has brought a long-standing dispute before the International Court of Justice to a close. This article critically analyzes some of the most interesting topics raised in this judgement, not least the fact that it was harshly criticized by a very high number of judges in their individual opinions. The issues discussed – such as the role of self-defence law within the confines of an ‘FCN treaty’ or the notion of ‘freedom of commerce’ – merely point to higher-level problems of a theoretical nature which cause our confusion as to substantive law.
The Milošević Trial at the Halfway Stage: Judgement on the Motion for Acquittal
Authors: GAPARAYI IDI
Published: December 2004

On 16 June 2004 Trial Chamber III of the ICTY issued a judgement on a motion for dismissal of charges in the Milošević case. Brought forward by the amici curiae appointed by the trial chamber, the motion for acquittal achieved limited success. While some allegations were dismissed, particularly with respect to the Bosnia Indictment, overall, the trial chamber found that the prosecution had led sufficient evidence to support each of the counts challenged in the three indictments against the accused. This article highlights some of the significant developments in the trial's first two years and the issues raised in the motion for acquittal, as well as the trial chamber's determination.
Tempered Adversariality: The Judicial Role and Trial Theory in the International Criminal Tribunals
Authors: KEEN PETER CARMICHAEL
Published: December 2004

International criminal procedure (ICP) has fluctuated uncertainly between common- and civil-law procedural principles. Consensus on the principles underlying ICP is needed to ensure consistent standards of justice. The article begins by comparing criminal procedure in common- and civil-law systems, and describes the theories underlying the trial and judicial role in these systems. It then compares ICP to civil- and common-law criminal procedure. This comparison establishes the scope of judicial powers that can be exercised by international criminal judges. These powers differ from those exercised by both common- and civil-law judges. The article concludes by arguing that ICP is based on a new theory of the trial: the theory of ‘tempered adversariality’.
Impacts of the North Atlantic Oscillation and the El Niño–Southern Oscillation on Danube river flow variability
Authors: Rimbu N. , Dima M. , Lohmann G. , Stefan S.
Published: December 2004

Based on analysis of observational data we show that the impact of the North Atlantic Oscillation (NAO) and El Niño–Southern Oscillation (ENSO) on the Danube river flow variability shows important decadal variations. A lag‐correlation analysis reveals that winter SST from tropical Pacific and some regions from the North Atlantic are significantly correlated with the streamflow variations from spring and summer suggesting a possible predictive skill of the Danube river flow anomalies in these seasons using winter SST as a predictor.
Stable isotope and chemical systematics of pseudotachylyte and wall rock, Homestake shear zone, Colorado, USA: Meteoric fluid or rock‐buffered conditions during coseismic fusion?
Authors: Moecher David P. , Sharp Zachary D.
Published: December 2004

A hydrous fluid phase is critical in controlling effective stress and fault mechanics, and influencing the mineralogy and strength of materials within fault zones. Oxygen and hydrogen isotope and chemical analysis of wall rock gneiss, pseudotachylyte, and selected minerals in gneiss and pseudotachylyte from the Homestake shear zone was used to assess whether melting occurred in the presence of meteoric water or involved only minor amounts of H2O derived from micas in wall rock gneiss. Bulk pseudotachylyte has slightly lower δ18OSMOW than the whole rock protolith. δD for one bulk pseudotachylyte is essentially identical to biotite in gneiss; δD for two samples is lower by ∼20‰. Bulk pseudotachylyte has lower SiO2 and K2O, and higher Al2O3, FeO, MgO, CaO, and H2O, than gneiss. The lower SiO2 of pseudotachylyte compared to gneiss is explained by physical segregation of 25 to 72 volume % of quartz clasts from the mobile melt phase. Samples of gneiss and pseudotachylyte define a SiO2‐δ18O mixing line between quartz and the most SiO2‐ and 18O‐depleted pseudotachylyte. Physical segregation of quartz (highest oxygen isotope composition in the pseudotachylyte‐gneiss system) accounts for the slightly lower oxygen isotope composition of bulk pseudotachylyte relative to gneiss. The similar δD of pseudotachylyte and biotite from gneiss in one sample is consistent with dehydration melting of biotite during frictional heating and dissolution of biotite‐derived H2O in the melt. Late devitrification of glass and formation of greater amounts of fine‐grained muscovite, accompanied by 10–30% loss of hydrogen as H2O, results in lower δD values in other samples. In general, melt generation occurred in a fault zone closed to infiltration of meteoric water. There was no free, H2O‐rich pore fluid present at the time of slip to potentially influence the behavior of the fault.
Nitric acid loss rates measured in power plant plumes
Authors: Neuman J. A. , Parrish D. D. , Ryerson T. B. , Brock C. A. , Wiedinmyer C. , Frost G. J. , Holloway J. S. , Fehsenfeld F. C.
Published: December 2004

Measurements of HNO3, NOx, NOy, and CO2 in the plumes from electric utility power plants located in eastern Texas are used to determine the HNO3 loss rates in the planetary boundary layer during plume transport. These 1 Hz measurements were obtained from the National Center for Atmospheric Research Electra aircraft flying on clear afternoons in a well‐mixed planetary boundary layer during the Texas Air Quality Study in August and September of 2000. The analysis uses data obtained in 48 crosswind transects of plumes from seven different power plants on six flight days. The NOx lifetime was found to vary from 1.3 to 3.1 hours in these plumes, indicating that the measurements were obtained during periods of rapid photochemical activity. The HNO3 loss rate was 0.45 ± 0.21 hour−1 in power plant plumes that were advected over rural regions. Particle size distributions measured in the plumes indicated that gas phase HNO3 was not lost to particle formation. Meteorological effects and land use were also investigated as possible causes for the observed HNO3 loss rates, which were insensitive to the land cover and measured wind speeds and boundary layer heights. The HNO3 loss rate measured in most plumes was more than 4 times greater than what is calculated from deposition velocities and the measured boundary layer height.
Delineation of hydrochemical facies distribution in a regional groundwater system by means of fuzzy c‐means clustering
Authors: Güler Cüneyt , Thyne Geoffrey D.
Published: December 2004

In this paper, classification of a large hydrochemical data set (more than 600 water samples and 11 hydrochemical variables) from southeastern California by fuzzy c‐means (FCM) and hierarchical cluster analysis (HCA) clustering techniques is performed and its application to hydrochemical facies delineation is discussed. Results from both FCM and HCA clustering produced cluster centers (prototypes) that can be used to identify the physical and chemical processes creating the variations in the water chemistries. There are several advantages to FCM, and it is concluded that FCM, as an exploratory data analysis technique, is potentially useful in establishing hydrochemical facies distribution and may provide a better tool than HCA for clustering large data sets when overlapping or continuous clusters exist.
Calculating exchange rates for water trading in the Murray‐Darling Basin, Australia
Authors: Etchells Teri , Malano Hector , McMahon Thomas A. , James Barry
Published: December 2004

Water markets have the potential to greatly improve the productive use of water by reallocating entitlements to where they are most highly valued. However, trading can actually reduce the volumetric reliability of other parties' entitlements if relatively more water needs to be supplied to the transferred entitlement after the trade. Exchange rates are a conversion factor applied to the traded entitlement volume to account for third party impacts caused when the water is consumed in a new location. The calculation of exchange rates must consider the inherent uncertainties associated with the volume supplied between years and across valleys. This paper explains the application of exchange rates in overcoming third party effects from trade and demonstrates the calculation of exchange rates for a case study of permanent intervalley trade between four valleys in the Murray‐Darling Basin, Australia. Also, it identifies the “seller matched” method as the most desirable system for determining the volume of water to be transferred each season to supply the traded entitlement.
Climate precursors of multidecadal drought variability in the western United States
Authors: Hidalgo Hugo G.
Published: December 2004

Low‐frequency (periodicities lower than 20 years) hydrologic variability in the western United States over the past 500 years is studied using available tree‐ring reconstructions of Palmer Drought Severity Index (PDSI), streamflow, and climate indices. Leading rotated principal component (RPC) scores of a gridded tree‐ring reconstruction of the PDSI from 1525 to 1975 are significantly correlated with indices representing large‐scale climate variations from the Pacific and Atlantic Oceans. RPC1 (31%) is related to the influence of North Pacific sea surface temperature (SST) variations, indexed by the Pacific Decadal Oscillation (PDO). RPC2 (24%) is apparently related to North Atlantic SST variations, indexed by the Atlantic Multidecadal Oscillation (AMO). RPC3 (19%) is moderately correlated with a smoothed version of the Southern Oscillation Index. Consistent with recent studies of instrumental data, RPC1 (PDO) and RPC2 (AMO) explain a large part of the multidecadal hydrologic variability of the interior western United States. Western U.S. PDSI variability exhibits significant pentadecadal (and longer) oscillations in the epochs from circa 1525 to 1650 and 1850 to 1975, while bidecadal oscillations are prevalent in the middle epoch from circa 1650 to 1850. The changes in spectral characteristics of western U.S. PDSI were related to similar changes in the PDO (and therefore in RPC1). In contrast, RPC2 had a regular periodicity of 51 years for the past ∼500 years. This regularity is intriguing, and although RPC2 was primarily related to the AMO in this study, the influence from Pacific climate cannot be discarded.
Enhanced Landau damping of finite amplitude electrostatic waves in the presence of suprathermal electron tails
Authors: Rose D. V. , Guillory J. , Beall J. H.
Published: December 2004

Increased Landau damping of electrostatic waves in the presence of low density suprathermal electron populations is examined. An electrostatic dispersion analysis is compared directly with one-dimensional particle-in-cell simulations of the Landau damping rates. An analytic damping rate formula is presented that is in good agreement with numerical solutions of the dispersion equation over a range of parameters.
Bihelical magnetic relaxation and large scale magnetic field growth
Authors: Blackman Eric G.
Published: December 2004

A unified, three-scale system of equations accommodating nonlinear velocity driven helical dynamos, as well as time-dependent relaxation of magnetically dominated unihelical or bihelical systems is derived and solved herein. When opposite magnetic helicities of equal magnitude are injected on the intermediate and small scales, the large scale magnetic helicity grows kinematically (independent of the magnetic Reynolds number) to equal that on the intermediate scale. For both free and driven relaxation large scale fields are rapidly produced. Subsequently, a dissipation-limited dynamo, driven by growth of small scale kinetic helicity, further amplifies the large scale field. The results are important for astrophysical coronae fed with bihelical structures by dynamos in their host rotators. The large scale for the rotator corresponds to the intermediate scale for the corona. That bihelical magnetic relaxation can produce global scale fields may help to explain the formation of astrophysical coronal holes and magnetohydrodynamic outflows.
Modeling of nonlinear electron cyclotron resonance heating and current drive in a tokamak
Authors: Kamendje Richard , Kasilov Sergei V. , Kernbichler Winfried , Pavlenko Ivan V. , Poli Emanuele , Heyn Martin F.
Published: December 2004

Electron cyclotron resonance heating and current drive are modeled in tokamak geometry taking into account nonlinear wave-particle interaction and the inhomogeneity of the distribution function on magnetic surfaces. The model includes self-consistently coupled beam tracing and Monte Carlo computations of the electron distribution function. The method of Green’s function for the computation of the generated current is described. For the Axisymmetric Divertor Experiment Upgrade [Leuterer et al., Fusion Eng. Des. 53, 485 (2001)] parameters and high beam focusing, nonlinear wave-particle interaction effects appear to be important for perpendicular launch of the microwave beam and not important for oblique launches where they stay below the “threshold.” With defocusing the beam two to three times along the direction of the magnetic field nonlinear effects of wave-particle interaction start to be important also for oblique launches. The effect of decreased current in case of increasing the microwave beamwidth is demonstrated. The decrease of both power absorption and generated current around low-order rational magnetic surfaces is found. Its possible effect on the tearing mode stability index is discussed.
Toward improved consistency of a priori tests with a posteriori tests in large eddy simulation
Authors: Park Noma , Yoo Jung Yul , Choi Haecheon
Published: December 2004

It is well known that conventional a priori tests based on the instantaneous true subgrid scale (SGS) stress do not provide a useful diagnostic information on deterministic SGS models due to the stochastic nature of unresolved scales. In this study, the possibility of an alternative diagnostics based on the “best deterministic” model is investigated. The optimal SGS model [J. A. Langford and R. D. Moser, “Optimal LES formulation for isotropic turbulence,” J. Fluid Mech. 398, 321 (1999)] is considered as one of nearly best deterministic models. The validity of the optimal model is confirmed by a posteriori test, showing that the field from the optimal large eddy simulation can be regarded as one of the representative fields among all the possible realizations of filtered direct numerical simulation. Then, a priori and a posteriori tests for several SGS models are performed on the forced isotropic turbulence with a sharp cutoff filter. It is shown that a priori tests based on the optimal model are highly consistent with a posteriori tests. Also, dynamic eddy viscosity models are very close to the optimal model both in a priori and a posteriori senses, which implies that the accurate prediction of backward dissipation is not necessarily required for the deterministic model to predict accurate flow statistics at least for the isotropic turbulence. Therefore, the direct application of scale-invariance concept to the resolved field is shown to be unsuccessful for the spectral cutoff filter. The present study strongly suggests that this concept should be realized in terms of the dynamic constant(s) of dissipative models.
Experimental observation of resonance overlap responsible for Hamiltonian chaos
Authors: Doveil F. , Auhmani Kh. , Macor A. , Guyomarc’h D.
Published: December 2004

A test electron beam is propagated in a specially designed traveling wave tube. The beam intensity is low enough to ensure that beam-plasma instabilities are ruled out. By recording the beam energy distribution at the output of the tube, we report the experimental observation of the resonant domain of a single wave and of the overlap of the resonance domains of two waves associated to the destruction of Kolmogorov–Arnold–Moser tori constituting barriers in phase space. This overlap mechanism is responsible for the transition to large scale chaos common to a large class of Hamiltonian systems.
The electrostatic sheath in an electronegative dusty plasma
Authors: Wang Zheng-Xiong , Liu Jin-Yuan , Liu Yue , Wang Xiaogang
Published: December 2004

Bohm criterion for the electrostatic sheath in electronegative dusty plasmas, which are composed of electrons, negative and positive ions, as well as dust grains, is investigated with Sagdeev potential, taking into account the self-consistent dust charge variation. The numerical solutions show that the dust and negative ion densities, as well as the positive ion and dust Bohm velocities, all have effects on the dust charge at the sheath edge. The positive ion and dust Bohm velocities increase with the growth of the dust density, while both of them decrease with the growth of negative ion density. Furthermore, the interactions between the two Bohm velocities are considered. The results are examined and found to be reliable by the quantitative analysis of Sagdeev potential.
Direct numerical simulation of polymer-induced drag reduction in turbulent boundary layer flow
Authors: Dimitropoulos Costas D. , Dubief Yves , Shaqfeh Eric S. G. , Moin Parviz , Lele Sanjiva K.
Published: December 2004

We describe a method for direct numerical simulation of polymer-induced friction drag reduction in turbulent boundary layers. The effect of the polymer additives that induce spatial variations of skin-friction drag is included in the momentum equation through a continuum constitutive model for the viscoelastic stress, which is based on the evolution of a parameter describing the fluid microstructure. We demonstrate that the turbulence structure and polymer microstructure evolve asynchronously as one moves in the streamwise direction. We observe an initial development length, which is followed by a quasisteady region where variations in drag reduction are weak. High drag reduction behavior can be present at short downstream distances from the inflow plane.
Ultra-Compact Dwarf Galaxies in Galaxy Clusters
Authors: Drinkwater Michael J. , Gregg Michael D. , Couch Warrick J. , Ferguson Henry C. , Hilker Michael , Jones J. Bryn , Karick Arna , Phillipps Steven
Published: December 2004

We review the evidence that the ultra-compact dwarf (UCD) galaxies we recently discovered in the Fornax Cluster form a new, previously unknown class of galaxies and we discuss possible scenarios for their formation. We then present recent results that UCDs are also present in the Virgo Cluster, and that there is a much larger than expected population of fainter UCDs in the Fornax Cluster. The size and properties of this population may lead us to revise our original ‘galaxy threshing’ hypothesis for the formation of UCDs.
Galactic Winds and the Missing Baryons
Authors: Veilleux Sylvain , Rupke David S.
Published: December 2004

Galaxy-scale winds are poised to solve a number of ailments in modern cosmology. However, we know little about trends of wind properties with host galaxy properties. In an attempt to quantify the impact of galactic winds on their host galaxies and the environment, we are conducting a systematic survey of star-forming and active galaxies at z = 0–0.5. Preliminary results on the star-forming galaxies are presented.
Human Rif1 protein binds aberrant telomeres and aligns along anaphase midzone microtubules
Authors: Xu Lifeng , Blackburn Elizabeth H.
Published: December 2004

We identified and characterized a human orthologue of Rif1 protein, which in budding yeast interacts in vivo with the major duplex telomeric DNA binding protein Rap1p and negatively regulates telomere length. Depletion of hRif1 by RNA interference in human cancer cells impaired cell growth but had no detectable effect on telomere length, although hRif1 overexpression in S. cerevisiae interfered with telomere length control, in a manner specifically dependent on the presence of yeast Rif1p. No localization of hRif1 on normal human telomeres, or interaction with the human telomeric proteins TRF1, TRF2, or hRap1, was detectable. However, hRif1 efficiently translocated to telomerically located DNA damage foci in response to the synthesis of aberrant telomeres directed by mutant-template telomerase RNA. The hRif1 level rose during late S/G2 but hRif1 was not visible on chromosomes in metaphase and anaphase; however, notably, specifically during early anaphase, hRif1 aligned along a subset of the midzone microtubules between the separating chromosomes. In telophase, hRif1 localized to chromosomes, and in interphase, it was intranuclear. These results define a novel subcellular localization behavior for hRif1 during the cell cycle.
CD27 Expression Promotes Long-Term Survival of Functional Effector–Memory CD8+Cytotoxic T Lymphocytes in HIV-infected Patients
Authors: Ochsenbein Adrian F. , Riddell Stanley R. , Brown Michele , Corey Lawrence , Baerlocher Gabriela M. , Lansdorp Peter M. , Greenberg Philip D.
Published: December 2004

Human immunodeficiency virus (HIV)-specific CD8+ T cells persist in high frequencies in HIV-infected patients despite impaired CD4+ T helper response to the virus, but, unlike other differentiated effector cytotoxic T lymphocytes, most continue to express the tumor necrosis factor receptor family member CD27. Because the ligand for CD27 (CD70) is also overexpressed in HIV-infected hosts, we examined the nature of expression and potential functional consequences of CD27 expression on HIV-specific CD8+ T cells. Analysis of CD27+ and CD27− T cells derived from the same HIV-specific clone revealed that retention of CD27 did not interfere with acquisition of effector functions, and that after T cell receptor stimulation, CD27+ cells that concurrently were triggered via CD27 exhibited more resistance to apoptosis, interleukin 2 production, and proliferation than CD27− T cells. After transfer back into an HIV-infected patient, autologous HIV-specific CD27− T cells rapidly disappeared, but CD27+ T cells derived from the same clone persisted at high frequency. Our findings suggest that the CD27–CD70 interaction in HIV infection may provide CD27+ CD8+ T cells with a survival advantage and compensate for limiting or absent CD4+ T help to maintain the CD8 response.
Dynamic Repositioning of CD4 and CD8 Genes during T Cell Development
Authors: Delaire Stephanie , Huang Yina Hsing , Chan Shaio Wei , Robey Ellen A.
Published: December 2004

Although stable repression of CD4 and CD8 genes is a central feature of T cell lineage commitment, we lack detailed information about the timing and mechanism of this repression. Stable gene repression has been linked to the position of genes within the nucleus. Therefore, information about the nuclear position of CD4 and CD8 genes during T cell development could provide insights into both the mechanism of regulation of CD4 and CD8 genes, and the process of lineage commitment. Here, we report that lineage-specific repression of CD4 and CD8 genes is associated with the repositioning of alleles close to heterochromatin. We also provide evidence that the relocalization of CD4 and CD8 genes to heterochromatin can occur as an early response to positive selection signals. We discuss our results in terms of our current knowledge of CD4 and CD8 gene regulation and CD4 versus CD8 lineage commitment.