bluuebunny/crossref_metadata_2025_split huggingface dataset:
Historic Eruptions of Tambora (1815), Krakatau (1883), and Agung (1963), their Stratospheric Aerosols, and Climatic Impact
Authors: Rampino Michael R. , Self Stephen 
Published: December 2004

AbstractDecreases in surface temperatures after the eruptions of Tambora (1815), Krakatau (1883), and Agung (1963) were of similar magnitude, even though the amount of material (dust and volatiles) injected into the stratosphere by these three events differed greatly. Large amounts of fine ash and volatiles were dispersed into the upper atmosphere by Krakatau and Tambora; the Agung eruption in 1963 was a much smaller, vulcanian-type eruption which injected dust and volatiles into the stratospheric aerosol layer more directly. Analyses of magmatic volatiles indicate that the Agung eruption was proportionately richer in SO2 and Cl than either Tambora or Krakatau. Relative amounts of fine ash produced by the Tambora, Krakatau, and Agung eruptions are estimated at about 150:20:1, whereas the masses of atmospheric sulfate aerosols produced were on the order of 7.5:3:1.Decreases in surface temperature of a few tenths of a degree C for several years following volcanic eruptions are primarily a result of the sulfate aerosols, rather than of the silicate dust. The similarity in the atmospheric response after these three eruptions supports the idea of limiting mechanisms on volcanic stratospheric-aerosol loading, which is suggested by microphysical processes of aerosol particles. Fluctuations in stratospheric aerosol optical depth seem to be controlled to a large degree by high-intensity sulfur-rich eruptions (e.g., Agung, 1963), which may however be relatively small in total ejecta volume. Such eruptions leave little geologic record, but appear as acidity peaks in polar ice cores.
Recent Seasonal Rainfall and Temperature Relationships in Peninsular Florida
Authors: Coleman James M. 
Published: December 2004

AbstractRainfall and temperature records for the last half century are analyzed for peninsular Florida. A recent increase in winter precipitation, weakening toward the south, appears to be related to the temperature decline of the last several decades. Autumn decrease in precipitation in the last two decades is apparently due to suppression of tropical cyclonic activity. The reverse of both of these trends was evident prior to the 1940s. These climatic patterns have resulted in seasonal redistribution of precipitation throughout the Florida peninsula and extended drought conditions for the southern half of the peninsula.
Comparisons of210Pb and Pollen Methods for Determining Rates of Estuarine Sediment Accumulation
Authors: Brush Grace S. , Martin E. Ann , DeFries Ruth S. , Rice Cynthia A. 
Published: December 2004

AbstractComparisons of sedimentation rates obtained by210Pb and pollen analyses of 1-m cores collected throughout the Potomac Estuary show good agreement in the majority of cores that can be analyzed by both methods. Most of the discrepancy between the methods can be explained by the analytical precision of the210Pb method and by the exactness with which time horizons can be identified and dated for the pollen method. X-radiographs of the cores and the distinctness of the pollen horizons preclude significant displacement by reworking and/or mixing of sediments. Differences between the methods are greatest where uncertainties exist in assigning a rate by one or both methods (i.e.,210Pb trends and/or “possible” horizon assignments). Both methods show the same relative rates, with greater sediment accumulation more common in the upper and middle estuary and less toward the mouth. The results indicate that geochronologic studies of estuarine sediments should be preceded by careful observation of sedimentary structures, preferably by X-radiography, to evaluate the extent of mixing of the sediments. Time horizons, whether paleontologic or isotopic, are generally blurred where mixing has occurred, precluding precise identification. Whenever possible, two methods should be used for dating sediments because a rate, albeit erroneous, can be obtained isotopically in sediments that are mixed; accurate sedimentation rates are also difficult to determine where the time boundary is a zone rather than a horizon, where the historical record does not provide a precise date for the pollen horizon, or where scouring has removed some of the sediment above a dated pollen horizon.
The Overkill Hypothesis as a Plausible Explanation for the Extinctions of Late Wisconsin Megafauna
Authors: Spaulding W. Geoffrey 
Published: December 2004

AbstractThe pulse of large mammal extinctions at the close of the last ice age was a pronounced ecological catastrophe in the Western Hemisphere. Available paleoenvironmental, paleontological, and archeological data are largely concordant with the “overkill” hypothesis proposing that human predation was the cause of these extinctions. Climatic explanations fail to postulate specific mechanisms accounting for the event's timing, differential impact, geographic extent, and stratigraphic singularity. Lack of provisional acceptance of the overkill hypothesis, when no viable alternatives exist, may be in part because this unconventional hypothesis violates a strong sociocultural bias, the image of prehistoric man as the “noble savage”.
Late Wisconsin Groundwater Discharge Environments of the Southwestern Indian Springs Valley, Southern Nevada
Authors: Quade Jay , Pratt William L. 
Published: December 2004

AbstractBadland exposures in the Indian Springs Valley, southern Nevada, contain evidence of formerly widespread spring and seep discharge. The stratigraphic position and appearance of most of these deposits suggests correlation with late Wisconsin (30,000 to ca. 10,000 yr B.P.) marsh sediments in nearby Las Vegas Valley. Previously, all these deposits have been loosely described as lacustrine because of the presence of extensive green mudstones associated with aquatic mollusks. However, this association also typifies modern groundwater discharge environments in many basins of northeast Nevada such as the Steptoe Valley, basins often without hydrographic closure. Such analogs best explain the origin of late Wisconsin fine-grained deposits in the unclosed southwestern arm of the Indian Springs Valley. Key features of these depositional systems are the lack of shoreline deposits, the presence of a broad belt of subaerially deposited plae-brown silts surrounding spring, “wet meadow,” and marsh deposits, and the intermixture of terrestrial and aquatic mollusks in most horizons where mollusks occur.
Absence of Altonian Glaciation in Illinois
Authors: Curry B. Brandon 
Published: December 2004

AbstractIllinois was free of glacier ice from about 130,000 to 25,000 yr B.P. Deposits of this time interval in northeastern Illinois, represented by core samples from test-hole ISGS S-30, are composed of leached, nonglacigenic, stratified, or pedoturbated silty sediments that typically are organic-rich and pedogenically modified. These deposits overlie the Sangamon Soil, which is identified by its stratigraphic position, soil morphology, and distinct alteration products in the clay-mineral fraction, including a variably swelling vermiculite-like phase and a randomly interstratified kaolinite/10 Å phase. The regional extent of these deposits suggests that if Altonian ice existed in the Lake Michigan basin, it did not extend westward beyond the cuesta of Silurian dolomite that rims the southwestern shore of Lake Michigan.
Vegetation Response to Climatic Change in Central Rift Valley, Kenya
Authors: Mworia Maitima Joseph 
Published: December 2004

AbstractPollen analysis of a 15.5-m sediment core from Lake Naivasha, central Rift Valley of Kenya, reveals that the vegetation from before 20,290 to nearly 12,000 yr B.P. was dominated by open grassland, indicating arid conditions. Within this period a moderately wetter climate existed between 17,000 and 15,000 yr B.P., shown by relatively slight increase in both the montane and lowland forest vegetation. From approximately 12,000 to 6500 yr B.P., a change toward more trees and forests started at lower altitudes around the basin of Lake Naivasha, and later in the higher montane regions. After 6000 yr B.P. a decline in forest and lowland trees opened the vegetation into more grasslands and by 4000 yr B.P. a vegetation similar to the present was attained and has persisted to the present. During this period shallow-water aquatic plants became abundant in Lake Naivasha.
Climatic, Solar, Oceanic, and Geomagnetic Influences on Late-Glacial and Holocene Atmospheric 14C/12C Change
Authors: Stuiver Minze , Braziunas Thomas F. , Becker Bernd , Kromer Bernd 
Published: December 2004

AbstractLate-glacial and Holocene 14C/12C ratios of atmospheric CO2 vary in magnitude from a few per mil for annual/decadal pertubations to more than 10% for events lasting millennia. A data set illuminating 10- to 104-yr variability refines our understanding of oceanic (climatic) versus geomagnetic or solar forcing of atmospheric 14C/12C ratios. Most of the variance in the Holocene atmospheric 14C/12C record can be attributed to the geomagnetic (millennia time scale) and solar (century time scale) influence on the flux of primary cosmic rays entering the atmosphere. Attributing the observed atmospheric 14C/12C changes to climate alone leads to ocean circulation and/or global wind speed changes incompatible with proxy records. Climate-(ocean-)related 14C redistribution between carbon reservoirs, while evidently playing a minor role during the Holocene, may have perturbed atmospheric 14C/12C ratios measurably during the late-glacial Younger Dryas event. First-order corrections to the radiocarbon time scale (12,000–30,000 14C yr B.P.) are calculated from adjusted lake-sediment and tree-ring records and from geomagnetically defined model 14C histories. Paleosunspot numbers (100–9700 cal yr B.P.) are derived from the relationship of model 14C production rates to sunspot observations. The spectral interpretation of the 14C/12C atmospheric record favors higher than average solar activity levels for the next century. Minimal evidence was found for a sun-weather relationship.
Interglacial Deposits at Birch Creek, Northeast Interior Alaska
Authors: Edwards Mary E. , McDowell Patricia F. 
Published: December 2004

AbstractA 12-m sequence of lake sediment and peat in a 45-m high exposure on Birch Creek, northeast Alaska, contains pollen of Picea, Betula, Alnus and Populus, and wood of Picea and Populus. This sequence, which may represent 10,000 yr of more of accumulation, is beyond the limit of radiocarbon dating. It lies between two units of loess; the underlying loess lies above the Old Crow Tephra, recently dated at 149,000 ± 13,000 yr B.P. The lake sediments probably were deposited during the last interglaciation (isotope substage 5e) and subsequently buried by Wisconsinan loess. Analogs for the ancient lake may be deep, long-lived thaw lakes that are present in the modern landscape. When Birch Creek is correlated with other sites across nonglaciated Alaska and northwest Canada, there appears to be a common interglacial signal in sediments overlying the Old Crow Tephra.
A dot-blot ELISA comparable to immunoblot for the specific diagnosis of human parastrongyliasis
Authors: Eamsobhana P. , Yoolek A. , Punthuprapasa P. , Suvouttho S. 
Published: December 2004

AbstractA dot-blot enzyme-linked immunosorbent assay (dot-blot ELISA) using an electroeluted 31-kDa glycoprotein from adult worms of Parastrongylus cantonensis as the specific antigen was evaluated for the immunological diagnosis of patients infected with P. cantonensis. The sensitivity and specificity for the detection of serum antibody to P. cantonensis in dot-blot ELISA were both 100%, as determined with serum samples of ten P. cantonensis-infected patients, 60 patients with other related parasitic infections, and 20 uninfected controls. The test was as sensitive and specific as the immunoblot test which revealed a reactive band of 31 kDa. Both the dot-blot ELISA and immunoblot detected all sera from ten P. cantonensis-infected individuals, but not with those of other heterologous parasitoses (gnathostomiasis, toxocariasis, filariasis, paragonimiasis, cysticercosis and malaria) or sera from healthy controls. The dot-blot ELISA is much simpler to perform than the immunoblot technique, and the test can be applied under field conditions where sophisticated facilities are lacking.
Density Modulation Experiments on HT-7 Tokamak
Authors: K. Tanaka  , Gao Xiang  , Jie Yin-Xian  , R. Sakamoto  , K. Toi  
Published: December 2004

Density modulation experiments are successfully conducted on HT-7 ohmic discharge to investigate particle transport coefficients: diffusion coefficients D and convection velocity V. The particle transport is studied at low (1.5×1019 m−3) and high (3×1019 m−3) density regimes. The clear differences are observed that D is 0.42 m2 /s and 0.17 m2/s,Vis 4.7 m/s (outward) and 1.6 m/s (inward) for low and high density plasmas respectively, where spatially constant D andV(r) = (r/a)V0were assumed for the analysis.
Hiring and Dismissal Costs in Theory and Practice: A Comparison of Institutional Constraints and Employment Adjustment Patterns in Six OECD Countries
Authors: Kraft Kornelius 
Published: December 2004

SUMMARYThis paper reports the results of a comparison of employment adjustment in Japan, the United States and four major EC countries. Output and real wages are used in explaining the optimal employment level and change in employment. Short‐ and long run responses to alterations of the exogenous variables are estimated and compared. Surprisingly, Germany has a quite rapid adjustment of labor while France and Italy show a much slower adjustment pattern. Even in comparison with the United States. Great Britain demonstrates the fastest adjustment to changes in the economic environment. By far the slowest adjustment pattern is realized in Japan. Overall the difference between the US and Europe seems not to be too large and European labor markets are not as sclerotic as occasionally assumed.ZUSAMMENFASUNGDieser Artikel gibt die Ergebnisse eines Vergleichs der Beschäftigungsanpassung in Japan, den Vereinigten Staaten und den vier wichtigsten EU‐Landern wieder. Das Produktionsniveau und der Reallohn sind die erklarenden Variablen für das optimale Beschaftigungsniveau wie auch Veranderungen der Beschäftigung. Es werden kurz‐ und langfnstige Beziehungen zwischen den exogenen und der endogenen Vanablen geschatzt und verglichen Uberraschenderweise hat Deutschland eine relativ rasche Beschaftigungsanpassung, während Frankreich und Italien eine viel langsamere Anpassung aufweisen. Großbntannien hat auch im Vergleich zu den USA die schnellste Reaktion auf Veränderungen der ökonomischen Umwelt. Das bei weitem inflexibelste Anpassungsverhalten wird für Japan registriert. Zusammenfassend scheinen die Unterschiede zwischen den Vereinigten Staaten und Europa nicht so groß und der europaische Arbeitsmarkt nicht so sklerotisch zu sein wie erwartet.RÉSUMÉCet article présente les résultats d'une comparaison de la vitesse d'adaptation de l'emploi au Japon, aux Etats‐Unis et dans les quatre pays les plus importants de l'UE. Le niveau de l'emploi optimal ***ainsi que les variations de l'emploi sont expliquées par le niveau de production et les salaires réels. Les variations à court et long terme des changements des variables exogènes ont été estimés et comparés. Étonnamment, l'Allemagne a une vitesse d'adaptation de l'emploi relativement rapide par rapport à celles de la France et de l'Italie. L'Angleterre montre měme, en comparaison avec les Etats‐Unis, une plus grande flexibilité envers les modifications de l'environnement économique. L'adaptation la plus lente est observée au Japon. Pour conclure les différences concernant la vitesse d'adaptation de l'emploi entre les Etats‐Unis et l'Europe ne semblent pas si grandes et les marchés de travail européens sont moins sclérosés que ce que l'on attendait.
Review article: Barrett's oesophagus and associated adenocarcinoma – a UK perspective
Authors: Fitzgerald R. C. 
Published: December 2004

SummaryIn the UK and across the Western world there has been a rapid increase in oesophageal adenocarcinoma, such that this cancer is now more common than squamous cell carcinoma. The 5‐year mortality from oesophageal adenocarcinoma is >80% and therefore there has been increasing interest in the pre‐malignant condition Barrett's oesophagus. Barrett's oesophagus is defined by a visible columnar‐lined segment with histopathological evidence of a glandular epithelium, which typically contains intestinal metaplasia. Once Barrett's oesophagus is diagnosed, most centres in the UK offer endoscopic surveillance with the aim to detect early, curable lesions. Surveillance in its current form is cumbersome and expensive, and new endoscopic and molecular developments are hoped to improve the yield of such procedures. The current treatments are symptomatic control of reflux symptoms, with more definitive treatments usually reserved for patients with at least high‐grade dysplasia. There is interest in chemoprevention strategies, including proton‐pump inhibitors, cyclo‐oxygenase‐2 inhibitors and aspirin, but to date none of these have proven effective. Treatment options for high‐grade dysplasia include surgery, endoscopic mucosal resection (in the context of a visible lesion) and photodynamic therapy. Comparative studies between various geographical regions, as the predominant histopathological subtypes of oesophageal cancer change, may give us some clues about the pathogenesis of Barrett's adenocarcinoma.
Evidence‐based risk factors for postoperative deep vein thrombosis
Authors: Edmonds Michael J. R. , Crichton Timothy J. H. , Runciman William B. , Pradhan Malcolm 
Published: December 2004

Background:  Deep vein thrombosis (DVT) is a common postoperative complication that is associated with significant morbidity and mortality. Thromboprophylaxis has been shown to be underused. In the absence of prophylaxis, rates as high as 50% have been reported following orthopaedic surgery, and 25% following general surgery. Many risk factors have been suggested but there is often little evidence to support these claims.Methods:  A systematic review was performed to determine the evidence base behind each suggested risk factor, and, where sufficient data were available, a random‐effects meta‐analysis was performed.Results:  There is evidence to support a significant association between increased age, obesity, a past history of thromboembolism, varicose veins, the oral contraceptive pill, malignancy, Factor V Leiden gene mutation, general anaesthesia and orthopaedic surgery, with higher rates of postoperative DVT, although there remain some variables within the study designs that may lead to overestimation of effect. There is no evidence to support the suggested risk factors of hormone replacement therapy, gender, ethnicity or race, chemotherapy, other thrombophilias, cardiovascular factors, smoking and blood type.Conclusions:  An accurate knowledge of evidence‐based risk factors is important in predicting and preventing postoperative DVT, and can be incorporated into a decision support system for appropriate thromboprophylaxis use.
Teaching subfascial perforator veins surgery: survey on a 2‐day hands‐on course
Authors: Rulli Francesco , Cina Gregorio , Galatà Gabriele , Cina Alesssandro , Vincenzoni Claudio , Fiorentino Alessandro , Farinon Attilio Maria 
Published: December 2004

Background : The present paper describes a training method with objective evaluation to enhance video‐assisted surgical skills in subfascial endoscopic perforator veins surgery (SEPS). Training was scheduled during a 2‐day intensive course.Methods : Hands‐on exercises were performed (i) on a simulator to assess whether specific training exercises were helpful in attainment of skills; (ii) on a known animal model that uses the swine abdominal wall and which allows practice in endoscopic dissection and perforator veins (PV) using appropriate instrumentation in an environment that is a reasonable surrogate for the human calf; and (iii) assisting a senior surgeon performing SEPS. Thirty surgeons without experience in SEPS were trained to perform a sequence of standardized drills connected with the SEPS technique. The SEPS simulator consisted of an artificially constructed subfascial space of the leg in which false perforator veins had to be localized, and cut. The participants performed a sequence of drills three times in order to improve their dexterity. The same exercises were then performed on a swine model. The model consisted of the arteries and veins penetrating the rectus fascia and passing into the overlying cutaneous trunci muscle and hypodermis on either side of the midline between the arch of the ribs cranially and the umbilicus caudally. Trainees were required to achieve operative space in the animal subcutaneous fat, to reach and identify the ‘perforating’ subcutaneous vessels, and to interrupt some of them with a 5‐mm clamp coagulator ultrasonic scalpel. The time required to perform each dexterity drill was recorded in seconds. Finally, the day after, trainees were asked to drive the senior operator during clinical SEPS performed on eight patients, suggesting the following manoeuvres in order to: (i) enter the subfascial space of the leg; (ii) make operative space; (iii) identify the incompetent perforator vein(s); and (iv) coagulate and divide them with the ultrasonic scalpel. Each of these four steps scored 1 point.Results : All the trainees showed a steady improvement in skill acquisition on the SEPS simulator (P < 0.001), and on the animal model with the single‐port technique (P < 0.001). These results reflect positively on the animal model using the dual‐port technique, and on the scores achieved in the operating theatre during clinical SEPS.Conclusions : The validity of the 2‐day course was demonstrated by significant improvement in performance with increasing skill on the training models, and in clinical practice.
Characterization of the Novel
Fusobacterium nucleatum
Plasmid pKH9 and Evidence of an Addiction System
Authors: Bachrach Gilad , Haake Susan Kinder , Glick Alon , Hazan Ronen , Naor Ronit , Andersen Roxanna N. , Kolenbrander Paul E. 
Published: December 2004

ABSTRACT

Fusobacterium nucleatum
is an important oral anaerobic pathogen involved in periodontal and systemic infections. Studies of the molecular mechanisms involved in fusobacterial virulence and adhesion have been limited by lack of systems for efficient genetic manipulation. Plasmids were isolated from eight strains of
F. nucleatum
. The smallest plasmid, pKH9 (4,975 bp), was characterized and used to create new vectors for fusobacterial genetic manipulation. DNA sequence analysis of pKH9 revealed an open reading frame (ORF) encoding a putative autonomous rolling circle replication protein (Rep), an ORF predicted to encode a protein homologous to members of the FtsK/SpoIIIE cell division-DNA segregation protein family, and an operon encoding a putative toxin-antitoxin plasmid addiction system (
txf-axf
). Deletion analysis localized the pKH9 replication region in a 0.96-kbp fragment. The pKH9
rep
gene is not present in this fragment, suggesting that pKH9 can replicate in fusobacteria independently of the Rep protein. A pKH9-based, compact
Escherichia coli-F. nucleatum
shuttle plasmid was constructed and found to be compatible with a previously described pFN1-based fusobacterial shuttle plasmid. Deletion of the pKH9 putative addiction system (
txf-axf
) reduced plasmid stability in fusobacteria, indicating its addiction properties and suggesting it to be the first plasmid addiction system described for fusobacteria. pKH9, its genetic elements, and its shuttle plasmid derivatives can serve as useful tools for investigating fusobacterial properties important in biofilm ecology and pathogenesis.