bluuebunny/crossref_metadata_2025_split huggingface dataset:
Geochemical gradients and artifact mass densities on the lowermost Bed II eastern lake margin (~ 1.8 Ma), Olduvai Gorge, Tanzania
Authors: Deocampo Daniel M. , Tactikos Joanne C. 
Published: October 2010

AbstractBulk geochemistry of ~ 1.8 Ma lacustrine claystone at Olduvai Gorge, Tanzania, is controlled principally by the geochemistry of ultrafine (< 0.1 μm), authigenic clay minerals. Authigenic clays have an average structural formula of (Si3.83Al0.17)(Al0.43Fe0.49Mg0.84)(Na0.99K0.22Ca0.16)O10(OH)2; octahedral composition varies, with Mg/(Al + Fe) ranging from 0.7 to 2.3. These clay minerals have a complex history of interaction with saline, alkaline water, followed by secondary diagenetic reactions that leached Mg in freshwater paleoenvironments. Lateral variations in whole-rock and clay geochemistry show westward enrichment in Mg, from Mgoct= 0.6–1.6. This is consistent with persistence of saline, alkaline Paleolake Olduvai to the west, and the presence of groundwater wetlands and other freshwater paleoenvironments to the east. Stone artifact mass density also varies systematically across the basal Bed II deposits, ranging from 100.0to 104.3g of artifacts per cubic meter of excavated sediment. Significant correlation is found between clay geochemistry and the density of artifacts excavated from associated archeological trenches (r2= 0.59, p < 0.01). This relationship supports models of hominin land use in which artifact use and discard is concentrated near freshwater paleoenvironments such as wetlands associated with surface and groundwater discharge. Independent paleoenvironmental proxies such as clay geochemistry allow quantitative hypothesis testing to improve our understanding of early hominin behavior and paleoecology.
Timing of glaciation and last glacial maximum paleoclimate estimates from the Fish Lake Plateau, Utah
Authors: Marchetti David W. , Harris M. Scott , Bailey Christopher M. , Cerling Thure E. , Bergman Sarah 
Published: October 2010

AbstractThe High Plateaus of Utah include seven separate mountain ranges that supported glaciers during the Pleistocene. The Fish Lake Plateau, located on the eastern edge of the High Plateaus, preserves evidence of at least two glacial advances. Four cosmogenic 3He exposure ages of boulders in an older moraine range from 79 to 159 ka with a mean age of 129 ± 39 ka and oldest ages of 152 ± 3 and 159 ± 5 ka. These ages suggest deposition during the type Bull Lake glaciation and Marine Oxygen Isotope Stage (MIS) 6. Twenty boulder exposure ages from four different younger moraines indicate a local last glacial maximum (LGM) of ~ 21.1 ka, coincident with the type Pinedale glaciation and MIS 2. Reconstructed Pinedale-age glaciers from the Fish Lake Plateau have equilibrium-line altitudes ranging from 2950 to 3190 m. LGM summer temperature depressions for the Fish Lake Plateau range from −10.7 to −8.2°C, assuming no change in precipitation. Comparison of the Fish Lake summer temperature depressions to a regional dataset suggests that the Fish Lake Plateau may have had a slight increase (~ 1.5× modern) in precipitation during the LGM. A series of submerged ridges in Fish Lake were identified during a bathymetric survey and are likely Bull Lake age moraines.
Clinical comparison of two self‐directed bleaching systems
Authors: Karpinia Katherine , Magnusson Ingvar , Barker Matthew L. , Gerlach Robert W. 
Published: October 2010

Purpose This randomized clinical trial compared the clinical efficacy and tolerability of 2 marketed self‐directed vital tooth‐whitening systems.Materials and Methods Balancing for baseline tooth color, self‐reported coffee/tea use, and age, 57 adult volunteers were randomized to either a whitening strip containing 6% hydrogen peroxide or a tray‐based 10% carbamide peroxide/dentifrice/mouth rinse combination system. Following the manufacturer’ s directions, the strip group bleached twice daily for 30 minutes, whereas the tray group bleached twice daily for 20–30 minutes, preceded by tooth brushing with a whitening dentifrice and followed by mouth rinsing with a whitening solution. Treatment extended for 14 days, with evaluation at day 7 and again at day 14. Whitening response was measured objectively as L*a*b* from standardized digital images of maxillary anterior teeth. Tolerability was assessed by oral examination and subject interview. Efficacy comparisons were made using analysis of covariance, whereas tolerability was compared using the nonparametric Wilcoxon rank‐sum test.Results Both treatments resulted in statistically significant (P < 0.01) improvements from baseline for all color parameters. For between‐group comparisons, the 6% hydrogen peroxide strips yielded a nearly 3‐fold reduction in yellowness (Δb*), a nearly 2‐fold improvement in lightness (ΔL*), 2.6 times greater redness reduction (Δa*), and a more than 2‐fold change in overall color (ΔE*) compared to the tray‐based combination system. Between‐group comparisons were statistically significant for the all color parameters at both the day 7 and day 14 evaluations (P < 0.001). In general, 7‐day use of the whitening strips provided significantly greater color improvement relative to the combination dentifrice/gel/rinse system at day 14. In addition, the groups differed significantly (P < 0.05) in bleaching tolerability severity‐days, with the strip system demonstrating better overall tolerability compared to the combination system.Conclusions The single‐step 6% hydrogen peroxide strips demonstrated better overall clinical response, in terms of both tooth‐whitening efficacy and tolerability, than the multiple‐step tray‐based combination system.
Effect of surface‐charged poly(methyl methacrylate) on the adhesion of Candida albicans1
Authors: Park Sang E. , Periathamby Antony Raj , Loza Juan C. 
Published: October 2010

Purpose The aim of this study was to investigate the ability of a new surface‐modified denture resin to reduce adhesion of Candida albicans to the denture surface. This material has a negative charge incorporated by copolymerization of methacrylic acid to methyl methacrylate. An in vitro system was designed to assess the adhesion of C. albicans to surface‐charged poly(methyl methacrylate) (PMMA) surfaces.Materials and Methods Four experimental groups consisted of a control (pure PMMA) and 3 groups of modified PMMA (mPMMA) (95:5, 90:10, and 80:20 MMA: methacrylic acid). Four resin samples (11 × 5 mm) for each experimental group were made to enable the adhesion assay. Resin samples of varying ratios of methacrylic acid were placed in C. albicans suspensions, and the adherent cells were stained with Gram’ s crystal violet. The surface area of adherent C. albicans was examined for the entire sample using the computer image at a magnification of × 25. Percentage of surface area of adherent C. albicans colonies was averaged and compared between the control and each experimental group. Analysis of variance and Bonferroni’ s multiple‐comparisons test were performed on the data.Results As the ratio of incorporated methacrylic acid to PMMA increased, the surface area of adherent C. albicans decreased. Analysis of data revealed a significant decrease in C. albicans adhesion to the resin blocks (p < 0.0001) when the methacrylic acid was present at 10% of the PMMA. There also existed a correlation between the surface area of adherent C. albicans and the contact angle measurement as the ratio of methacrylic acid changed. Surface contact angle analysis of resin surfaces revealed that as the amount of methacrylic acid increased, the surface energy of the resins increased.Conclusions The present results support the role of electrostatic interaction in adhesion, and introduce an effective method of reducing adhesion of C. albicans to PMMA surfaces through modification of the surface charge of polymeric biomaterials.
Current concepts and techniques in complete denture final impression procedures
Authors: Petropoulos Vicki C. , Rashedi Behnoush 
Published: October 2010

Purpose In 2001, a survey of U.S. dental schools was conducted to determine which concepts, techniques and materials are currently prevalent in the teaching of final impression procedures for complete dentures in the predoctoral clinical curriculum.Materials and Methods The questionnaire was mailed to the chairperson of the prosthodontic/restorative departments of 54 U.S. dental schools. Of these, 44 schools returned the completed survey resulting in a response rate of 82%.Results Results from this survey show that the majority of schools (71%) teach the selective‐pressure technique for final impression making; the majority of the schools (64%) use modeling plastic impression compound for border molding the final impression tray; 39% of the schools do not place vent holes in the final impression tray, 30% of schools place more than one hole and 27% place one hole only; the majority of the schools (98%) are using custom trays for final impressions. Ninety‐eight percent of the schools are border molding the custom tray and 70% of schools are using a visible light‐cured (VLC) composite resin material to make the trays. Thirty‐six percent of the schools are teaching the Boucher impression technique and 34% are teaching the modified Boucher impression technique.Conclusions Predoctoral clinical complete denture educational programs agree on many aspects of final impression making, however, there is variability in their teachings regarding the impression philosophy and the materials used.
Hearing and ossicular chain preservation in cholesteatoma surgery
Authors: Obholzer R , Ahmed J , Warburton F , Wareing M J 
Published: October 2010

AbstractObjective:To assess the hearing changes associated with sacrificing an intact ossicular chain during cholesteatoma surgery.Methods:We reviewed the operation notes of surgical procedures performed by the senior author between October 2000 and April 2006. Thirty-three cases were identified in which cholesteatoma surgery had been performed in the presence of a mobile, intact ossicular chain. One set of case notes was missing; therefore, 32 cases were included in the analysis. The ossicular chain was preserved in 17 cases (14 males and three females) and sacrificed in 15 (eight males and seven females).Results:At the first post-operative assessment, a median air–bone gap deterioration of 3.3 dB was seen in patients in whom the ossicular chain had been sacrificed, while a median air–bone gap improvement of 3.3 dB was seen in those in whom the chain had been preserved. However, multivariable logistic regression analysis suggested that this difference in hearing outcomes was due to pre-operative hearing status, and that preservation of the ossicular chain did not lead to a better outcome.Conclusions:In cholesteatoma surgery, there is at most a marginal benefit in preserving the ossicular chain. In the current study, the better hearing outcomes associated with preservation of the ossicular chain were accounted for by patients' better pre-operative hearing status. This study did not demonstrate a difference in residual disease rate, but was underpowered to do so.
Population structure of nurse sharks, Ginglymostoma cirratum (Orectolobiformes), caught off Ceará State, Brazil, south-western Equatorial Atlantic
Authors: Santander-Neto Jones , Shinozaki-Mendes Renata A. , Silveira Leonardo M. , Jucá-Queiroz Bruno , Furtado-Neto Manuel A.A. , Faria Vicente V. 
Published: October 2010

The nurse shark, Ginglymostoma cirratum, is considered an endangered species in Brazil and its capture by fisheries forbidden. Despite such legislation, nurse sharks continue to be caught as these laws are unenforced and fisheries are not monitored. The goal of the present study was to describe the population structure of nurse sharks caught off Ceará State, north-eastern Brazil, based on the following aspects: abundance and size, sex-ratio, fisheries incidence and seasonality of captures. Landings were monitored weekly during a two-year period. A total of 189 specimens were recorded. Total length (TL) varied between 73 and 274 cm. The male–female ratio did not differ significantly (1.19♀:1♂). TL of individuals landed as carcasses was estimated based on interdorsal length. The following equation was obtained for males and females: TL = 12.606ID + 14.24 (R2 = 0.9505). Most of the landed sharks were juveniles (86.2%). No seasonal pattern of abundance and TL variation was observed. Management of this fishery is required in order to prevent localized over-fishing of nurse sharks.
Presence of Dosidicus gigas paralarvae (Cephalopoda: Ommastrephidae) in the central Gulf of California, Mexico related to oceanographic conditions
Authors: Camarillo-Coop Susana , Salinas-Zavala César A. , Manzano-Sarabia Marlenne , Aragón-Noriega Eugenio Alberto 
Published: October 2010

The jumbo squid Dosidicus gigas is the only ommastrephid commercially caught in Mexico. Despite the economic and ecological importance of this species, little is known about its early life stages. The relationship between the presence of paralarvae and mesoscale oceanic features was investigated for the first time in the central Gulf of California, Mexico in February, April, June and September of 2008. A total of 86 paralarvae were found only in June and September (summer season), in the well-stratified column water where the thermocline was evident and warm sea surface waters (27.7° to 29.4°C) dominated. The greatest abundance of D. gigas paralarvae was observed within 2.23 to 3.48 km of the main front. The mantle length of the smallest paralarvae corresponded with the mantle length at hatching. The San Pedro Mártir Island–Santa Rosalia transect and Santa Rosalia–Guaymas transect were determined as the main hatching localities in June and September respectively. The number of paralarvae found in this study contrast with the potential fecundity of mature females which are found throughout the year.
Small-scale effect of intertidal seagrass (Zostera muelleri) on meiofaunal abundance, biomass, and nematode community structure
Authors: Leduc Daniel , Probert P. Keith 
Published: October 2010

Seagrass beds are common features of coastal ecosystems worldwide, and their associated infauna are often more productive and diverse than in unvegetated habitats. Little is known, however, about the ecology of meiofaunal communities living in seagrass sediments. We compared the abundance and biomass of sediment meiofauna inside and outside an intertidalZostera muelleribed in southern New Zealand to assess the impact of seagrass cover on meiofaunal distribution. Nematode community structure, diversity, and feeding groups were also compared between habitats and sediment depths (0–2, 2–5 and 5–10 cm) to evaluate the effect of seagrass on nematode communities. Meiofaunal biomass was significantly higher inside than outside theZ. muelleribed, but secondary productivity inside the bed is likely to have been limited by the availability of labile organic matter. There were significant differences in nematode community structure between unvegetated, sparsely vegetated, and densely vegetated sites (102 m scale), as well as between sediment depths (cm scale). No significant differences were found in depth-integrated (0–10 cm) nematode diversity between sites, but vertical gradients in diversity differed between vegetated and unvegetated sites. Epistrate feeders were the most common feeding group in unvegetated sediments whereas most feeding groups were common inside the seagrass bed. Findings from this study indicate that seagrass beds can have a marked impact on infaunal structure and function over small spatial scales through their effect on sediment characteristics and organic matter input. Some unexpected trends observed in the present study, i.e. low meiofaunal biomass at the vegetated sites, and lower abundance of copepods inside than outside the seagrass bed, suggest that the nature of seagrass–invertebrate interactions may depend on habitat characteristics and the identity and ecology of species considered.
E. M. FORSTER'SBILLY BUDDAND THE COLLABORATIVE WORK OF OPERA
Authors: Arjomand Minou 
Published: October 2010

On 9 January 1964, the 86-year-old E. M. Forster took a curtain call at the Covent Garden revival ofBilly Buddalongside his colibrettist, Eric Crozier. TheTimesreview of the event neglected to mention either of the librettists, prompting Forster to write:Dear Sir,I have read with interest and approval your article onAn Opera of Good and Evilin this morning'sTimes, but wish you could have managed to squeeze in a reference to Eric Crozier and myself. We did the Libretto. We worked on it in Britten's house for several weeks. We might reasonably be credited with having helped to interpret his intentions and his conception of Melville's intentions.Yours faithfully,E. M. Forster
Community-dwelling older adults' contextual experiencing of humour
Authors: DAMIANAKIS THECLA , MARZIALI ELSA 
Published: October 2010

ABSTRACTThe purpose of this exploratory study was to examine the contextual experiencing of humour by community-dwelling older adults. Data for this study consisted of audio-recorded, transcribed interviews with 20 older adults who had participated in a larger study of a number of dimensions associated with the process of ageing. Qualitative coding of the interview content was used to extract salient themes that identified types of humour experienced in different life contexts. The analysis of older adults' narratives about their day-to-day lives yielded four types of experienced humour: affiliative, self-enhancing, self-defeating, and authentic. Within an inter-personal context, expressing and appreciating humour contributed to sustaining positive social connections. The use of authentic humour and being able to laugh at one's self and life's uncontrollable circumstances appeared to support a positive sense of self and was adaptive for coping with the inevitable losses that accompany the ageing process, such as declining health status. The results of this study suggest that humour expression and appreciation may play an important role in managing the ageing process in ways that are adaptive especially in inter-personal contexts. Possibly health-care providers in both community and institutional settings need to be made aware of the benefits for older adults of experiencing humour in different life contexts.
Pooling Under Misspecification: Some Monte Carlo Evidence on the Kmenta and the Error Components Techniques
Authors: Baltagi Badi H. 
Published: October 2010

Two different methods for pooling time series of cross section data are used by economists. The first method, described by Kmenta, is based on the idea that pooled time series of cross sections are plagued with both heteroskedasticity and serial correlation.The second method, made popular by Balestra and Nerlove, is based on the error components procedure where the disturbance term is decomposed into a cross-section effect, a time-period effect, and a remainder.Although these two techniques can be easily implemented, they differ in the assumptions imposed on the disturbances and lead to different estimators of the regression coefficients. Not knowing what the true data generating process is, this article compares the performance of these two pooling techniques under two simple setting. The first is when the true disturbances have an error components structure and the second is where they are heteroskedastic and time-wise autocorrelated.First, the strengths and weaknesses of the two techniques are discussed. Next, the loss from applying the wrong estimator is evaluated by means of Monte Carlo experiments. Finally, a Bartletfs test for homoskedasticity and the generalized Durbin-Watson test for serial correlation are recommended for distinguishing between the two error structures underlying the two pooling techniques.
Interviewed by Nicholas M. Kiefer
Authors: Goldberger Arthur S. 
Published: October 2010

Econometrics as practiced by Arthur (Art) Goldberger demonstrates extraordinary sensitivity to issues of measurement and model specification, and unusual care and caution in interpretation of results, as well as a thorough and comprehensive mastery of econometric theory. His landmark 1964 book,Econometric Theory, set a new standard of rigor in econometrics, and at the same time treated the important problems posed by limited and qualitative dependent variables years before any other text. Art Goldberger's work ranges from early contributions to macro modeling through demand analysis, multivariate modeling with latent variables, and models for sample selectivity, to his highly regarded work on important social issues of heritability of IQ, effectiveness of public versus private schools, and measurement of salary discrimination. Goldberger's influential work, especially on modeling latent or unobservable variables, is widely known and applied in sociology and psychology as well as in economics. Art has been at Wisconsin for many years, and this association is an important reason for Wisconsin's continuing reputation as a leading center for quantitative social sciences.The quality and influence of Art Goldberger's work has earned him many professional honors. He is a Fellow of the Econometric Society, the American Statistical Association, the American Academy of Arts and Sciences, and the American Association for the Advancement of Science, and has twice been a Guggenheim Fellow. He is a Distinguished Fellow of the American Economic Association and a member of the National Academy of Sciences. Art gave the Woytinsky Lecture at the University of Michigan in 1985.This interview took place on May 5 in Art Goldberger's office overlooking Lake Mendota. Art's remarks cover a wide range of topics, and I hope they are of interest to social scientists generally as well as to econometricians.
Generic Uniform Convergence
Authors: Andrews Donald W.K. 
Published: October 2010

This paper presents several generic uniform convergence results that include generic uniform laws of large numbers. These results provide conditions under which pointwise convergence almost surely or in probability can be strengthened to uniform convergence. The results are useful for establishing asymptotic properties of estimators and test statistics.The results given here have the following attributes, (1) they extendresults of Newey to cover convergence almost surely as well as convergence in probability, (2) they apply to totally bounded parameter spaces (rather than just to compact parameter spaces), (3) they introduce a set of conditions for a generic uniform law of large numbers that has the attribute of giving the weakest conditions available for i.i.d. contexts, but which apply in some dependent nonidentically distributed contexts as well, and (4) they incorporate and extend themain results in the literature in a parsimonious fashion.
Relationships between lexical and phonological development in young children*
Authors: STOEL-GAMMON CAROL 
Published: October 2010

ABSTRACTOur understanding of the relationships between lexical and phonological development has been enhanced in recent years by increased interest in this area from language scientists, psychologists and phonologists. This review article provides a summary of research, highlighting similarities and differences across studies. It is suggested that the research falls into two categories with different goals and different methodological approaches: (1) child-centered studies that examine the influences active in the prelinguistic and early-word period, emphasizing individual developmental patterns and the active role played by the child; and (2) studies inspired by research on word processing in adults; these focus on the effects of the phonological and lexical characteristics of the ambient language on underlying representations and word learning in children. The article concludes with suggestions for integrating the findings from the two approaches and for future research.