bluuebunny/crossref_metadata_2025_split huggingface dataset:
Estimating Household Structure in Ancient China by using Historical Data: A Latent Class Analysis of Partially Missing Patterns
Authors: Liao Tim Futing 
Published: December 2004

SummarySocial data often contain missing information. The problem is inevitably severe when analysing historical data. Conventionally, researchers analyse complete records only. Listwise deletion not only reduces the effective sample size but also may result in biased estimation, depending on the missingness mechanism. We analyse household types by using population registers from ancient China (618–907 AD) by comparing a simple classification, a latent class model of the complete data and a latent class model of the complete and partially missing data assuming four types of ignorable and non-ignorable missingness mechanisms. The findings show that either a frequency classification or a latent class analysis using the complete records only yielded biased estimates and incorrect conclusions in the presence of partially missing data of a non-ignorable mechanism. Although simply assuming ignorable or non-ignorable missing data produced consistently similarly higher estimates of the proportion of complex households, a specification of the relationship between the latent variable and the degree of missingness by a row effect uniform association model helped to capture the missingness mechanism better and improved the model fit.
Smooth Backfitting in Practice
Authors: Nielsen Jens Perch , Sperlich Stefan 
Published: December 2004

SummaryCompared with the classical backfitting of Buja, Hastie and Tibshirani, the smooth backfitting estimator (SBE) of Mammen, Linton and Nielsen not only provides complete asymptotic theory under weaker conditions but is also more efficient, robust and easier to calculate. However, the original paper describing the SBE method is complex and the practical as well as the theoretical advantages of the method have still neither been recognized nor accepted by the statistical community. We focus on a clear presentation of the idea, the main theoretical results and practical aspects like implementation and simplification of the algorithm. We introduce a feasible cross-validation procedure and apply it to the problem of data-driven bandwidth choice for the SBE. By simulations it is shown that the SBE and our cross-validation work very well indeed. In particular, the SBE is less affected by sparseness of data in high dimensional regression problems or strongly correlated designs. The SBE has reasonable performance even in 100-dimensional additive regression problems.
Bivariate Location–Scale Models for Regression Analysis, with Applications to Lifetime Data
Authors: He Wenqing , Lawless Jerald F. 
Published: December 2004

SummaryThe literature on multivariate linear regression includes multivariate normal models, models that are used in survival analysis and a variety of models that are used in other areas such as econometrics. The paper considers the class of location–scale models, which includes a large proportion of the preceding models. It is shown that, for complete data, the maximum likelihood estimators for regression coefficients in a linear location–scale framework are consistent even when the joint distribution is misspecified. In addition, gains in efficiency arising from the use of a bivariate model, as opposed to separate univariate models, are studied. A major area of application for multivariate regression models is to clustered, ‘parallel’ lifetime data, so we also study the case of censored responses. Estimators of regression coefficients are no longer consistent under model misspecification, but we give simulation results that show that the bias is small in many practical situations. Gains in efficiency from bivariate models are also examined in the censored data setting. The methodology in the paper is illustrated by using lifetime data from the Diabetic Retinopathy Study.
A Jackknife Variance Estimator for Unequal Probability Sampling
Authors: Berger Yves G. , Skinner Chris J. 
Published: December 2004

SummaryThe jackknife method is often used for variance estimation in sample surveys but has only been developed for a limited class of sampling designs. We propose a jackknife variance estimator which is defined for any without-replacement unequal probability sampling design. We demonstrate design consistency of this estimator for a broad class of point estimators. A Monte Carlo study shows how the proposed estimator may improve on existing estimators.
Asymptotic Bias in the Linear Mixed Effects Model Under Non-Ignorable Missing Data Mechanisms
Authors: Saha Chandan , Jones Michael P. 
Published: December 2004

SummaryIn longitudinal studies, missingness of data is often an unavoidable problem. Estimators from the linear mixed effects model assume that missing data are missing at random. However, estimators are biased when this assumption is not met. In the paper, theoretical results for the asymptotic bias are established under non-ignorable drop-out, drop-in and other missing data patterns. The asymptotic bias is large when the drop-out subjects have only one or no observation, especially for slope-related parameters of the linear mixed effects model. In the drop-in case, intercept-related parameter estimators show substantial asymptotic bias when subjects enter late in the study. Eight other missing data patterns are considered and these produce asymptotic biases of a variety of magnitudes.
Proanthocyanidins – a final frontier in flavonoid research?
Authors: Dixon Richard A. , Xie De‐Yu , Sharma Shashi B. 
Published: December 2004

SummaryProanthocyanidins are oligomeric and polymeric end products of the flavonoid biosynthetic pathway. They are present in the fruits, bark, leaves and seeds of many plants, where they provide protection against predation. At the same time they give flavor and astringency to beverages such as wine, fruit juices and teas, and are increasingly recognized as having beneficial effects on human health. The presence of proanthocyanidins is also a major quality factor for forage crops. The past 2 years have seen important breakthroughs in our understanding of the biosynthesis of the building blocks of proanthocyanidins, the flavan‐3‐ols (+)‐catechin and (–)‐epicatechin. However, virtually nothing is known about the ways in which these units are assembled into the corresponding oligomers in vivo. Molecular genetic approaches are leading to an understanding of the regulatory genes that control proanthocyanidin biosynthesis, and this information, together with increased knowledge of the enzymes specific for the pathway, will facilitate the genetic engineering of plants for introduction of value‐added nutraceutical and forage quality traits.

Contents

Summary
9

I.
Introduction
9

II.
Sources and structures of proanthocyanidins
10

III.
Functions of proanthocyanidins in the plant
12

IV.
Proanthocyanidins and plant quality traits
13

V.
Flavanols, proanthocyanidins and human health
14

VI.
Biosynthesis of proanthocyanidins
16

VII.
Genetic manipulation of the proanthocyanidin pathway
23

VIII.
Conclusions and future prospects
24

Acknowledgements
25

References
25
On‐line executive control: An electromyographic study
Authors: Allain Sonia , Carbonnell Laurence , Burle Boris , Hasbroucq Thierry , Vidal Franck 
Published: December 2004

AbstractIn a choice reaction time (RT) task, electromyographic (EMG) recordings allowed us to fractionate RT into two subcomponents, namely premotor time and motor time. This has been done for correct trials and errors. The analysis of the EMG burst and motor time (between EMG onset and overt response) showed that the EMG burst amplitude was reduced and the motor time was longer for errors than for correct responses. In the same way as posterror slowing on the RT was interpreted as revealing between‐trials changes in executive control, the present data provide direct evidence for an on‐line, within‐trial, executive control.
Spawning Season and Nest Fidelity of Largemouth Bass in a Tropical Reservoir
Authors: Waters D. Scott , Noble Richard L. 
Published: December 2004

Abstract
Largemouth bass Micropterus salmoides, an intensively studied sport fish of temperate North America, have been introduced into tropical regions, but with little evaluation. Studies in Puerto Rico suggest that reproduction occurs over many months and that life spans are short and annual mortality rates high. We tracked 44 adult largemouth bass with ultrasonic telemetry over an 18-month period (two spawning seasons) to determine the temporal and spatial utilization of spawning grounds. During the 1998 spawning season, both males and females demonstrated high site fidelity to specific areas characteristic of spawning grounds over the first half of the calendar year. Within this period, two distinct spawning events were evident from fish movements and were subsequently verified by hatch frequencies of young. The two spawning events, from mid-January through March and from late May through June, coincided with highly fluctuating water levels. When levels were high, shallow, vegetated areas were available and used for spawning. The reoccupation of nest areas corroborates previous gonad analyses that suggested multiple partial spawns by individual fish. During the 1999 spawning season, water levels were high in January and spawning occurred for 3 weeks, but levels rapidly declined thereafter, minimizing reproduction. Both male and female largemouth bass exhibited strong homing and nest site fidelity by returning to previous nesting areas. Individual fish were observed nesting in the same spawning grounds, and several males repeatedly utilized the same nest site during each of the separate spawning events and during both years. Because in tropical reservoirs recruitment to the fishable largemouth bass stock is directly related to the abundance of age-0 fish, maintaining high, stable water levels during the spawning season should enhance the largemouth bass population.
Use of Prepositioned Areal Electrofishing Devices with Rod Electrodes in Small Streams
Authors: Schwartz John S. , Herricks Edwin E. 
Published: December 2004

Abstract
We describe the design, performance, and operation of prepositioned areal electrofishing devices (PAEDs) that use rod electrodes for sampling fish in mesohabitat units of a small stream. The flexibility in design offered by rod PAED designs is an improvement over previously reported designs and provides the capacity to specifically match fish immobilization range with varying mesohabitat shape and size under typical field sampling conditions. In our study, immobilization range was determined as the distance from an electrode at which a given voltage gradient (V/cm) resulted in immobilization of several warmwater fish species. For waters with a specific conductivity of about 700 μS/cm, the immobilization threshold was 0.14 V/cm for the 16 species tested. The maximum immobilization range was about 0.85 m when 350 V or more were applied to the rod PAEDs. We evaluated rod PAED performance by considering the effects of electrode length, electrode orientation, and voltage supply on voltage gradients around the electrodes. The results were used to develop general protocols for rod PAED operation. In three scenarios, we documented that electrode placement and voltage adjustment can be used to sample fish in 1.2–16.9-m2 mesohabitats at water depths up to 1.3 m. Based on the general protocols developed and outlined in this study, rod PAEDs can be used to quantify fish occupancy in the diverse set of mesohabitats commonly found in small streams.
An Evaluation of 5.87-cm and 6.03-cm Escape Rings for Blue Crab Callinectes sapidus Traps
Authors: Guillory Vincent , Allemand Ralph , King Kenny , Bare Lisa 
Published: December 2004

Abstract
Escape rings are used in traps for blue crab Callinectes sapidus to reduce sublegal (&lt;127 mm carapace width [CW]) catch. Two escape ring sizes (5.87 cm and 6.03 cm) were compared using laboratory-derived retention curves and catch data from control traps without rings and experimental traps with one of the two rings. Percent sublegal catch and large sublegal (117– 126 mm CW) catch per unit effort (CPUE) was significantly greater in traps with 5.87-cm rings than in traps with 6.03-cm rings. Catch per unit effort of legal (≥127 mm CW) blue crabs was not significantly different between the two experimental traps, although small legal (127–136 mm CW) CPUE was significantly lower in traps with 6.03 rings. The modal size of blue crabs increased from control traps to traps with 5.87-cm rings to traps with 6.03-cm rings. Retention curves by 5-mm size-groups corroborated trends depicted by field data. A lower retention of females than males was demonstrated. The larger escape ring was recommended to maximize the benefits of sublegal crab CPUE reduction.
Gear Effects on Marine Habitats: Harvesting Northern Quahogs in a Shallow Sandy Bed at Two Levels of Intensity with a Short Rake
Authors: MacKenzie Clyde L. , Pikanowski Robert 
Published: December 2004

Abstract
We studied the effects on invertebrate infauna and grain size of harvesting northern quahogs Mercenaria mercenaria with a short rake. The substrate was a mixture of medium-coarse sand (phi values, 0.847–1.159) that was covered by 0.5 m of water at low tide. Two experimental areas (I + II) in Raritan Bay, New Jersey, were subdivided into six 5.5-m × 5.5-m plots. We raked alternate plots, the unraked plots serving as controls. In area I, we raked the treatment plots once (in June 2000) and then sampled all plots for effects on invertebrates and grain size. The number of invertebrates in the five taxa we counted and the mean grain size did not differ significantly (P &gt; 0.05) between treatment and control. In area II, we raked the treatment plots three times, one month apart (in July, August, and September 2000) and then sampled all plots. The results for invertebrates and grain size were similar to those for area I. This study suggests that short raking once or repeatedly during a harvesting season in a shallow sandy substrate does not measurably alter numbers of invertebrates or sediment grain size.
Implications of a Migration Impediment on Shortnose Sturgeon Spawning
Authors: Cooke Douglas W. , Leach Steven D. 
Published: December 2004

Abstract
A population of shortnose sturgeon Acipenser brevirostrum was documented congregating at the base of Pinopolis Dam, Cooper River, South Carolina, during the February−March spawning season. Pinopolis Dam is a peaking hydroelectric facility and navigation lock located within the coastal plane, 77 km upriver of the mouth of the Cooper River at Charleston, South Carolina. In a 5-year radiotelemetry experiment, shortnose sturgeon did not pass upstream through the navigation lock but congregated at the base of the dam. As a result, a study was conducted to determine whether the tailrace was used as spawning habitat. The location is atypical of published descriptions of shortnose sturgeon spawning habitat in terms of a suite of characters, including distance upriver, tide, flow characteristics, and substrate. The river is tidally influenced for its entire length, and the bottom substrate in the tailrace is dominated by hard marl with negligible fine sediments such as silt and sand. Turbine discharge varies from 0 to 329 m3/s subdaily; current velocities during typical hydroelectric peaking discharge exceed 3 m/s. Egg sampling showed that successful spawning (i.e., fertilized eggs and developing embryos) occurred during the three spawning seasons sampled. Spawning was detected from 27 February through 29 March (1997–1999) at water temperatures ranging from 11.5°C to 19.0°C (mean = 14.5°C), reaching the highest levels published for shortnose sturgeon spawning. Active spawning and lack of upstream passage by shortnose sturgeon at this site suggest that physical blockage of migration may prevent fish from reaching preferred spawning habitat, probably to the detriment of the population.
Performance of Two Strains of Lake Trout Stocked in the Midlake Refuge of Lake Michigan
Authors: McKee Patrick C. , Toneys Michael L. , Hansen Michael J. , Holey Mark E. 
Published: December 2004

Abstract
To evaluate the performance of Seneca and Marquette strains of lake trout Salvelinus namaycush for restoring stocks in southern Lake Michigan, we compared relative abundance (fish per lift of 305 m of gill net), survival (slope of the decline in natural logarithms of relative abundance), growth (von Bertalanffy growth curves), and wounding rates by sea lamprey Petromyzon marinus of the 1984 and 1985 year-classes captured at ages 3–16 in fall gill-net assessments on the Sheboygan Reef and the Milwaukee nearshore area during 1987–2000. Marquette strain lake trout survived at a significantly higher rate than Seneca strain lake trout prior to age 3 but at similar rates after age 3. The 1984 year-class of lake trout survived at a significantly higher rate than the 1985 year-class of lake trout prior to age 3 but at similar rates after age 3. Emigration of lake trout from the Sheboygan Reef to the nearshore Milwaukee area was similar for the Marquette and Seneca strains but was higher for the 1984 year-class than the 1985 year-class. The mean relative abundance of the 1984 and 1985 year-classes of Marquette and Seneca strains of lake trout varied erratically with age but did not decline with age on the Sheboygan Reef and Milwaukee nearshore area. On the Sheboygan Reef, growth in length, expressed as asymptotic length (L∞), differed significantly between the Marquette and Seneca strains of lake trout but did not differ significantly between the 1984 and 1985 year-classes. On the Sheboygan Reef, wounding rates by sea lampreys did not differ significantly between the Marquette and Seneca strains of lake trout among size-classes (633–734, 735–836, and ≥837 mm) during 1994–2000. Our findings suggest that the performance of Marquette strain lake trout was superior to that of Seneca strain lake trout on the Sheboygan Reef in central Lake Michigan.
A Comparison of Atlantic Salmon Embryo and Fry Stocking in the Salmon River, New York
Authors: Coghlan Stephen M. , Ringler Neil H. 
Published: December 2004

Abstract
To assess the feasibility of restoring an extirpated species, it is crucial to identify the method of reintroduction that optimizes juvenile survival and growth so that adequate adult populations may be established. Because Atlantic salmon Salmo salar fry are relatively expensive to rear, we compared the efficacies of two embryo-stocking methods and one fry-stocking method in producing age-0 Atlantic salmon parr in the Salmon River, New York. As measured by resulting parr densities, there were no differences in survival rates between embryos stocked with and without protective hatching boxes; the mean survival of embryo-stocked fish to late summer was less than 0.01%. Fry stocking produced significantly greater densities of late-summer parr than did embryo stocking, with site-specific survival ranging up to 8%; the mean survival of fry was 2%. Considering the hatchery costs of rearing each life stage, the labor involved in stocking, and the resulting late-summer parr abundances, we recommend planting fry rather than embryos as a method of reintroducing Atlantic salmon. Additional studies are needed to evaluate the success of stocking older life stages of Atlantic salmon in the Salmon River, although factors other than juvenile survival are probably important in establishing and maintaining a spawning population.
Superconductivity at 7.5 K and ambient pressure in polycrystalline pressed samples of βp‐(BEDT‐TTF)2I3
Authors: Schweitzer Dieter , Gogu Emil , Grimm Hans , Kahlich Siegfried , Keller Heimo J. 
Published: December 2004

Polycrystalline pressed samples of β‐(BEDT‐TTF)2I3 exhibit bulk superconductivity, zero resistivity being observed at 3.2 K (see figure) a transition temperature which is surprisingly higher than that observed for single crystals of the same compound. magnified image
The effect of arsenicals on cell suspension cultures of the Madagascar periwinkle (Catharanthus roseus)
Authors: Cullen William R , Hettipathirana Deepthi , Reglinski John 
Published: December 2004

AbstractCatharanthus roseus cells were grown in the presence of arsenite, arsenate, methylarsonate and dimethylarsinate. Cell growth and arsenical uptake were monitored. Reduction of arsenate, methylation of arsenic and demethylation of methylarsenic species are described. Alkaloid production by the cells is dramatically influenced by the presence of arsenicals. 1H NMR studies of methylarsonate uptake by whole cells of C. roseus are reported.
Soluble metal–polymer catalysts in the hydrogenation of organic compounds
Authors: Karakhanov E A , Neimerovets E B , Dedov A G 
Published: December 2004

AbstractLiterature describing the use of soluble metal–polymer catalysts in the molecular hydrogenation of alkenes, alkynes, aromatic and heterocyclic compounds has been reviewed. Special attention has been paid to coordinated metallic and organometallic catalytic systems and highly dispersed colloidal metals stabilized with polymers. The influence of metals, polymers and solvents on the structures of active sites is discussed. The prospects for the application of soluble metal–polymer catalysts in organic synthesis are also considered.
Studies of the uptake and binding of trace metals in fungi. Part I: Accumulation and characterization of mercury and silver in the cultivated mushroom, Agaricus bisporus
Authors: Byrne A R , Tušek‐Žnidarič M 
Published: December 2004

AbstractThe champignon mushroom Agaricus bisporus was cultivated on compost labelled with the radioactive traers 110mAg and 203Hg and the uptake of these two metals studied. The radiotracer then served as an aid in elucidation and characterization of the fungal metal–protein species using gel chromatography. In the case of the silver–protein complex, but not of mercury, the majority of the metal was contained in the fractions of intermediate (ca 8000–10000 Da) molecular weight possibly corresponding to metallothioneins (MT) or MT‐like species.
An organometallic route for the preparation of ring‐substituted 2‐aryl‐propanoic and ‐butanoic acids
Authors: Gruselle M , Malezieux B , Jaouen G , Troitskaya L L , Sokolov V I 
Published: December 2004

AbstractThis communication presents a simple and efficient way to synthesize 2‐arylalkanoic acids via chromium carbonyl complexation.
Bioturbation recorded by a sedimentary siloxane horizon
Authors: Pellenbarg Robert E , Carhart Homer W 
Published: December 2004

AbstractA Puget Sound (Washington State, USA) sediment core was quantitatively analyzed for organic silicon content, as derived from post‐1945 release of poly(organo)siloxanes (silicones). The sedimentary silicone data record and preserve a smeared event horizon, dating the first appearance of silicones in the sediment column. This record of bioturbation preserved deep in the column appears somewhat in contrast to the record provided by 210Pb geochronology. Aliquots of the same core segments had been dated previously using 210Pb, and analyzed for silicone content, as reported in this study. Core samples older than 50 years showed no detectable silicone, as measured by a new procedure utilizing inductively coupled plasma emission spectroscopy, after solvent extraction to collect the silicone from gram‐sized sediment core samples.