bluuebunny/crossref_metadata_2025_split huggingface dataset:
Nicotine reversal effects of the benzoflavone moiety from Passiflora incarnata Linneaus in mice
Authors: Dhawan Kamaldeep , Kumar Suresh , Sharma Anupam 
Published: October 2002

AbstractA benzoflavone moiety (BZF) has recently been reported to be liable for many of the biological effects of the plant Passiflora incarnata Linneaus. In light of various reports mentioning the usefulness of P. incarnata in tobacco addiction, studies have been performed using four doses (1, 5, 10 and 20 mg/kg) of the bioactive BZF moiety isolated from the aerial parts of P. incarnata . In a 7‐day experimental regimen, mice (n = 5) were given nicotine hydrogen tartrate (2 mg/kg), and combinations of nicotine with four doses of BZF (NnP‐1, NnP‐5, NnP‐10 and NnP‐20) q.i.d. by the s.c. route. At the end of the 7 days of treatment, naloxone was given to the mice from all groups to induce a nicotine withdrawal syndrome.The mice that had been treated with 10 and 20 mg/kg dose of BZF concurrently with nicotine showed a significantly fewer number of withdrawal jumps relative to the group treated with nicotine alone (Nn group). Separately, in a 14‐day treatment regimen, mice (n = 10; for the N group, n = 12) were administered nicotine (2 mg/kg) and combinations of nicotine with four doses of BZF (NP‐1, NP‐5, NP‐10, NP‐20 groups) q.i.d. by the s.c. route. Spontaneous physical and behavioural signs of nicotine dependence were observed 3 hours after cessation of treatments on the 14th day. Mice administered with combinations of nicotine and 5, 10 and 20 mg/kg doses of BZF (i.e. NP‐5, NP10 and NP‐20 groups), exhibited less intensity and severity of withdrawal effects compared to the mice treated with nicotine alone. Those mice treated with the two highest doses of BZF,in combination with nicotine (NP‐10 and NP‐20), showed significantly fewer nicotine‐abstinence withdrawal jumps and normal ambulatory behaviour. BZF treatment prevented weight loss and resulted in normal performance in the swimming endurance test, which may be a measure of stress and/or depression. Similarly, acute administration of a single 20 mg/kg dose of BZF prevented some of the nicotine‐withdrawal effects; lower doses were almost inert. These studies, although preliminary, suggest that the BZF may have value in treating nicotine addiction.
Judging the Quality of Gene Expression-Based Clustering Methods Using Gene Annotation
Authors: Gibbons Francis D. , Roth Frederick P. 
Published: October 2002

We compare several commonly used expression-based gene clustering algorithms using a figure of merit based on the mutual information between cluster membership and known gene attributes. By studying various publicly available expression data sets we conclude that enrichment of clusters for biological function is, in general, highest at rather low cluster numbers. As a measure of dissimilarity between the expression patterns of two genes, no method outperforms Euclidean distance for ratio-based measurements, or Pearson distance for non-ratio-based measurements at the optimal choice of cluster number. We show the self-organized-map approach to be best for both measurement types at higher numbers of clusters. Clusters of genes derived from single- and average-linkage hierarchical clustering tend to produce worse-than-random results.[The algorithm described is available at http://llama.med.harvard.edu, under Software.]
Maize Opaque Endosperm Mutations Create Extensive Changes in Patterns of Gene Expression[W]
Authors: Hunter Brenda G. , Beatty Mary K. , Singletary George W. , Hamaker Bruce R. , Dilkes Brian P. , Larkins Brian A. , Jung Rudolf 
Published: October 2002

AbstractMaize starchy endosperm mutants have kernel phenotypes that include a brittle texture, susceptibility to insect pests, and inferior functional characteristics of products made from their flour. At least 18 such mutants have been identified, but only in the cases of opaque2 (o2) and floury2 (fl2), which affect different aspects of storage protein synthesis, is the molecular basis of the mutation known. To better understand the relationship between the phenotypes of these mutants and their biochemical bases, we characterized the protein and amino acid composition, as well as the mRNA transcript profiles, of nearly isogenic inbred lines of W64A o1, o2, o5, o9, o11, Mucuronate (Mc), Defective endosperm B30 (DeB30), and fl2. The largest reductions in zein protein synthesis occur in the W64A o2, DeB30, and fl2 mutants, which have ∼35 to 55% of the wild-type level of storage proteins. Zeins in W64A o5, o9, o11, and Mc are within 80 to 90% of the amount found in the wild type. Only in the cases of o5 and Mc were significant qualitative changes in zein synthesis observed. The pattern of gene expression in normal and mutant genotypes was assayed by profiling endosperm mRNA transcripts at 18 days after pollination with an Affymetrix GeneChip containing &gt;1400 selected maize gene sequences. Compared with W64A sugary1, a mutant defective in starch synthesis, alterations in the gene expression patterns of the opaque mutants are very pleiotropic. Increased expression of genes associated with physiological stress, and the unfolded protein response, are common features of the opaque mutants. Based on global patterns of gene expression, these mutants were categorized in four phenotypic groups as follows: W64A+ and o1; o2; o5/o9/o11; and Mc and fl2.
Avoidance and suppression of compensation code in a trace scheduling compiler
Authors: Freudenberger Stefan M. , Gross Thomas R. , Lowney P. Geoffrey 
Published: October 2002

Trace scheduling is an optimization technique that selects a sequence of basic blocks as a trace and schedules the operations from the trace together. If an operation is moved across basic block boundaries, one or more compensation copies may be required in the off-trace code. This article discusses the generation of compensation code in a trace scheduling compiler and presents techniques for limiting the amount of compensation code: avoidance (restricting code motion so that no compensation code is required) and suppression (analyzing the global flow of the program to detect when a copy is redundant). We evaluate the effectiveness of these techniques based on measurements for the SPEC89 suite and the Livermore Fortran Kernels, using our implementation of trace scheduling for a Multiflow Trace 7/300. The article compares different compiler models contrasting the performance of trace scheduling with the performance obtained from typical RISC compilation techniques.
There are two key results of this study. First, the amount of compensation code generated is not large. For the SPEC89 suite, the average code size increase due to trace scheduling is 6%. Avoidance is more important than suppression, although there are some kernels that benefit significantly from compensation code suppression. Since compensation code is not a major issue, a compiler can be more aggressive in code motion and loop unrolling. Second, compensation code is not critical to obtain the benefits of trace scheduling. Our implementation of trace scheduling improves the SPEC mark rating by 30% over basic block scheduling, but restricting trace scheduling so that no compensation code is required improves the rating by 25%. This indicates that most basic block scheduling techniques can be extended to trace scheduling without requiring any complicated compensation code bookkeeping.
French Sociology and Time: Origin, Development, and Current Research
Authors: Gadéa Charles , Lallement Michel 
Published: October 2002

AbstractFor French sociology, time has never been the central subject of an independent field of research. Without being neglected, the theme of time remains nevertheless on the fringe. In this field, there are neither networks nor academic journals which are well recognized. If we exclude Temporalistes (a journal which appeared for the first time in 1984 but whose circulation remains private), we have no journal similar to Time and Society, a first class academic showcase for the promotion and recognition of work devoted to its theme.The division of work in the French scientific community is used to this absence of visible evidence; time is a subject of research in different fields: work, education, health and organisations, without the various threads ever being woven together to produce a framework of coherent analysis.
Secondary chemistry of cultured mycobionts: formation of a complete chemosyndrome by the lichen fungus of Lobaria spathulata
Authors: Stocker-Wörgötter Elfie , Elix John A. 
Published: October 2002

AbstractThe study aimed to optimize culture conditions and nutrient requirements for theproduction of secondary metabolites by the cultured mycobiont Lobaria spathulata. This species proved to be an excellent model system for such studies, as the complete chemosyndromefound in the natural lichen thallus was repeatedly formed in the cultured mycobiont with differentiated, aerial mycelia. Nutrient media containing the disaccharide, sucrose, were found to favour both rapid growth and the production of typical lichen substances. Higher proportions of the secondary compounds were detected in the developing mycobiont than in mature lichen thalli.
Stratigraphic Context of Old Crow Tephra, Holitna Lowland, Interior Southwest Alaska
Authors: Waythomas Christopher F. , Lea Peter D. , Walter Robert C. 
Published: October 2002

AbstractA thick deposit of Old Crow tephra was discovered in a bluff exposure along the middle Holitna River near the Kulukbuk Hills (61°20′N latitude, 157°10′W longitude) in interior southwest Alaska. This locality is the southwesternmost-known deposit of Old Crow tephra in Alaska. Thickness and grain-size data from this site support a source volcano in the eastern Aleutian arc. Pleistocene stratigraphic sequences in the lowland are dominated by upward-fining eolian sand-sheet deposits and loess separated by organic silt. These deposits record at least two episodes of regional glaciation and an intervening nonglacial period (marine oxygen isotope stage 3, stage 5, or both). Old Crow tephra crops out near the top of the lower upward-fining eolian unit, indicating that the ash erupted near the end of an interval of periglacial eolian sedimentation. The sequence of eolian deposits that contain Old Crow tephra probably accumulated during the latter part of marine oxygen isotope stage 6, whereas the overlying eolian sequence formed during the last glaciation (stage 2). This stratigraphic position is consistent with other stratigraphic contexts for the tephra and with fission-track and thermoluminescence ages of ca. 140,000 ± 10,000 yr B.P.
Holocene Coral Reef Terraces and Coseismic Uplift of Huon Peninsula, Papua New Guinea
Authors: Ota Y. , Chappell J. , Kelley R. , Yonekura N. , Matsumoto E. , Nishimura T. , Head J. 
Published: October 2002

AbstractAs many as six levels of emerged Holocene coral terraces occur along 40 km of coastline on the Huon Peninsula, Papua New Guinea, recording uplift history since culmination of the postglacial transgression. The Holocene reef crest, ca. 6000 yr B.P., is tilted down to the northwest, parallel to the coast and concordant with the deformation of the last interglacial coral reef terrace, and descends from 23 to 12 m in the study area. The pattern and rate of deformation have been uniform in the late Quaternary because average uplift rates have remained the same since the last interglaciation. The Holocene terraces described here are erosional features with regressive encrusting corals, developed upon the Holocene transgressive reef. The multiple levels represent episodic, probably coseismic uplift, which has occurred repeatedly in the last ca. 6000 yr. Significant longshore variation in the age of the lowest terrace, from 1700 to 2500 yr B.P., suggests independent coseismic uplift on different sectors of the coast. This is supported by age-height relationships of the higher Holocene terraces. Nonlinear uplift during the Holocene, with recurrence intervals increasing toward the present, is clearly recorded by the regressive terraces in each subregion. Some of the Holocene regressive terraces grade laterally into fluvial terraces capped with debris-flow deposits, probably reflecting seismically triggered mass movement.
Discriminant Function Analysis of Glass Chemistry of New Zealand and North American Tephra Deposits
Authors: Shane Philip A.R. , Froggatt Paul C. 
Published: October 2002

AbstractMajor, trace, and rare earth element analyses of volcanic glass are used separately or in combination for correlating Quaternary tephras, often by graphical or simple comparative methods. We have taken a statistical approach using discriminant function analysis (DFA) to assess the relative discriminating power of the different elements in volcanic glasses from several tectonovolcanic provinces. We found that major oxides are powerful discriminating variables for widespread tephras from the Taupo Volcanic Zone in New Zealand and here they can be more discriminating than trace elements. A wide selection of tephras from the western United States can also be distinguished on major oxides alone, particularly those from Cascade Range volcanoes. For tephras from large intracontinental calderas, such as Long Valley or Yellowstone, REE and trace elements are more effective at discriminating than major oxides. However, tephras erupted from the Long Valley area can be distinguished on major oxide composition by DFA, despite their similar chemistry. The selection and relative significance of different elements for discriminating tephras depends on the total data set being compared, as well as the source volcano and the individual eruptive events. Caution must be exercised in the nonstatistical selection of compositional data for characterizing tephras: DFA is a more powerful and objective tool for the comparison of tephra chemistry.
Growth of an Intermittent Ice Sheet in Iceland during the Late Pliocene and Early Pleistocene
Authors: Geirsdóttir Áslaug , Eiríksson Jón 
Published: October 2002

AbstractDeep-sea paleoclimatic records show that the Quaternary climate around Iceland was, and probably still is, very sensitive to rapid shifts in North Atlantic oceanic circulation. Studies of several key sections in Iceland indicate that similar oscillations are reflected in the late Pliocene and early Pleistocene terrestrial stratigraphy. Correlations between six rock sequences in western, northern, eastern, and southern Iceland show a fairly distinct trend during the Pliocene-Pleistocene transition indicating the progressive growth of an ice sheet from southeast toward the north and west. The correlations are based on K/Ar dates and paleomagnetic studies. A total of 11 glacial horizons are recorded in a stratigraphic column from eastern Iceland extending back 6.5 myr. In western Iceland, 7 glacial horizons are preserved in a rock section dated from 7.0 to 1.8 myr, and in northern Iceland 14 glacial horizons are identified in a section that extends back to 9.0 myr. Well over 20 glacial horizons have been identified in the stratigraphic column in Iceland. Full-scale glacial-interglacial cyclicity with regional ice cover is indicated at approximately 2.6 myr. A further amplification leading to islandwide glaciations is identified at 2.2-2.1 myr. These results show that changes in the ice cover in Iceland correlate with the deep-sea oxygen isotope records from benthic and planktonic foraminifera as well as IRD studies from the North Atlantic.
Assemblage Data and Bone and Teeth Modifications as an Aid to Paleoenvironmental Interpretations of the Open-Air Pleistocene Site of Tighenif (Algeria)
Authors: Dauphin Yannicke , Kowalski Casimir , Denys Christiane 
Published: October 2002

AbstractVariations in the proportions of the various groups of Rodentia collected from eight stratigraphic levels at Tighenif had previously been interpreted as representing environmental (climatic) changes. However, the processes involved in the formation of assemblages are still not well understood. Examination of fragmentation, crystallinity, and chemical composition of fossil bones and teeth, compared to recent samples, shows that a possible explanation for the variations in frequencies is the differential preservation of skeletal remains. Thus, the evaluation of postmortem effects is essential in determining the accuracy of the fossil record. The abundance and composition of remains are governed by the complex interaction of many factors. As indicated by actualistic studies, direct deductions from fauna lists must be avoided as much as possible.
Thirty Thousand Years of Vegetation Changes in the Alabama Hills, Owens Valley, California
Authors: Koehler Peter A. , Anderson R.Scott 
Published: October 2002

AbstractTwenty packrat (Neotoma) middens recovered from three sites (1265-1535 m) in the Alabama Hills, Inyo County, California, provide a ca. 31,450-yr record of vegetation change. Located ca. 7 km east of the Sierra Nevada, the middens document that Utah juniper (Juniperus osteosperma), Joshua tree (Yucca brevifolia), and bitterbush (Purshia tridentata) occupied the site between 31,450 and 19,070 yr B.P. Joshua tree and bitterbush departed by ca. 17,760 yr B.P., with cliffrose (Purshia mexicana) and joint-fir (Ephedra viridis) appearing. By 13,350 yr B.P., blackbush (Coleogyne ramosissima) and cholla (Opuntia echinocarpa) entered the record. Between 9540 and 7990 yr B.P., Utah juniper and other species now extralocal to the sites departed and modern components such as wolfberry (Lycium andersonii) and rubber rabbitbrush (Chrysothamnus teretifolius) appeared. The middle Holocene records little variation in plant macrofossil composition; however, pollen analysis reflects an increase in aquatic pollen types which might suggest more-open conditions. The transition to the modern vegetation associations at the sites occurred after ca. 2800 yr B.P. The record from the Alabama Hills correlates well with that of other regional vegetation data but documents conditions of increasing aridity earlier than many other packrat midden sites. A shift in understory vegetation between 19,070 and 17,760 yr B.P. may reflect a transition from glacial maximum to post-maximum conditions in the eastern Sierra Nevada.
Holocene Environmental Change and River-Mouth Sedimentation in the Baie des Anges, French Riviera
Authors: Dubar Michel , Anthony Edward J. 
Published: October 2002

AbstractRiver mouths on the steep, high-relief coast of the French Riviera exhibit thick sequences of Holocene marine, estuarine, deltaic, and river channel-floodplain sediments that overlie basal fluvial Pleistocene gravel. Gravel is uncommon in most of the early to middle Holocene aggradational-progradational marine, estuarine, deltaic sediments, despite an ample supply from rock units in the steep adjoining uplands. River-mouth gravel is common only in late Holocene river channels and in barrier beaches perched on finer-grained nearshore sediments. Neither downslope grain-size fining on alluvial fans nor sediment stacking patterns during sea-level (base-level) rise readily account for the lack of early to middle Holocene gravel in the river-mouth sediment wedges. Holocene sea-level rise led to the storage of fine-grained sediments in shallow marine, estuarine, and deltaic environments in the present coastal zone. We infer that humid temperate conditions, a dense forest cover, landscape stabilization, and a regular quiescent river flow regime associated with the Atlantic climatic optimum limited gravel supply in the adjoining catchments and gravel entrainment downstream during the early Holocene. Sea-level stabilization in the middle and late Holocene coincided with a marked change in bioclimatic conditions toward the present Mediterranean-type regime, which is characterized by a less dense forest cover, soil erosion, and episodic catastrophic floods. The late Holocene was thus a time of downstream bedload channel aggradation, fine-grained floodplain and paludal sedimentation, and seaward flushing of clasts leading to the formation and consolidation of the gravel barrier beaches that bound the rivermouths and embayments.
Behavior of earnings, stock returns, accruals, and analysts' forecasts following negative annual earnings
Authors: Ettredge Michael , Toolson Richard , Hall Steve , Na Chongkil 
Published: October 2002

AbstractThis study documents the behavior of earnings, abnormal stock returns, analysts' earnings forecasts, and accounting accruals following years in which companies report negative annual earnings. Changes in accounting accruals (earnings minus operating cash flows) frequently are used as proxies for managerial manipulation of earnings numbers. Our evidence indicates that earnings typically increase sharply in the year following a loss. The earnings increases are due to improved operating cash flows, not to accounting “window dressing.” However, financial analysts expect even better earnings performance than the rebounding firms are able to provide. Investors also appear not to understand the post‐loss behavior of annual earnings. Therefore, the market commonly is disappointed by the earnings increases, and the result, on average, is negative excess stock returns. The excess returns are correlated with analysts' earnings forecast errors, which proxy for the market's failure to understand post‐loss earnings behavior.
Mergers and macro‐economic factors
Authors: Yagil Joseph 
Published: October 2002

AbstractThis study investigates the relationship between macro‐economic factors and the time pattern of the degree of merger activity in the U.S. economy. The results of the study imply that whether mergers are motivated by operating or financial synergy, they are closely related to macro‐economic factors. The findings also indicate that this relationship is stronger for pure conglomerate than for non‐conglomerate mergers, and that while the impact of the interest rate on “cash” mergers is positive, for “securities” mergers the impact is negative.
A nonparametric investigation of the 90‐day t‐bill rate
Authors: Barkoulas John T. , Baum Christopher F. , Onochie Joseph 
Published: October 2002

AbstractWe employ a nonlinear, nonparametric method to model the stochastic behavior of changes in the 90‐day U.S. T‐bill rate. The estimation technique is locally weighted regression (LWR), a nearest‐neighbor method, and the forecasting criteria are the root mean square error (RMSE) and mean absolute deviation (MAD) measures. We compare the forecasting performance of the nonparametric fit to the performance of two benchmark linear models: an autoregressive model and a random‐walk‐with‐drift model. The nonparametric fit results in significant improvements in forecasting accuracy as compared to benchmark linear models both in‐sample and out‐of‐sample, thus establishing the presence of substantial nonlinear mean predictability in the 90‐day T‐bill rate.