bluuebunny/crossref_metadata_2025 huggingface dataset:
Correlations between Palmitate Content and Agronomic Traits in Soybean Populations Segregating for the fap1, fapnc, and fan Alleles
Authors: Cardinal Andrea J. , Burton Joseph W.
Published: September 2007

Palmitate is the predominant saturated fatty acid in soybean oil. Major fap alleles that reduce palmitate content in seed oil also reduce seed yield. Breeders are interested in estimating the genotypic correlation between palmitate content and agronomic traits to predict unfavorable correlated responses to selection. The main objective of this study was to estimate the genotypic and phenotypic correlations between palmitate and linolenate contents and other traits in three populations segregating for the fapnc, fap1, and fan alleles and modifier genes. The populations derived from crosses of high‐yielding lines and improved low‐palmitate and low‐linolenate lines were grown in replicated trials in three environments. Significant positive genetic correlations between palmitate and yield and between palmitate and plant height were observed in all three populations. Linolenate content was genetically positively correlated with lodging in two populations and negatively correlated with oil content in three populations. Our results support the observation that the major fapnc or fap1 or both alleles reduced plant height and had a major negative effect on yield. These effects could be due to pleiotropy or linkage with unfavorable yield or height genes. The relative importance of pleiotropy and linkage has very different implications for oil quality breeding.
Optimization of the Marker‐Based Procedures for Pyramiding Genes from Multiple Donor Lines: II. Strategies for Selecting the Objective Homozygous Plant
Authors: Ishii T. , Yonezawa K.
Published: September 2007

For extended application of marker‐based plant breeding, strategies are discussed for selecting a high‐degree gene‐pyramided line from among progeny of a multiparentally produced heterozygous plant (root genotype). A strategy with combined use of haplo‐diploidization and crossing between selected plants will be highly efficient; selection starts with haplo‐diploidized plants raised from the root genotype, and in the absence of a plant with the objective marker genotype, two plants with the best complementary genotypes are crossed to produce a hybrid, which in turn is haplo‐diploidized for the next round of selection. In this strategy, even a plant having as many as 20 target markers can be obtained at an almost perfect certainty in about three rounds of selection with a maximum of 200 tested plants per round. When haplo‐diploidized plants are unavailable, a plant with the most promising marker genotype should be selected and self‐fertilized in each generation, or in the absence of any promising plant, two plants with the best complementary genotypes are crossed for the next round of selection. In this strategy, the number of tested plants in the first two generations counts when the markers are codominant, whereas the rounds of selection counts when the markers are dominant. Of various supplementary measures for this strategy, backcrossing the root genotype with one of the donors could be useful when the donor has more than 70% of all targeted markers.
Mapping QTLs for Resistance to Frosty Pod and Black Pod Diseases and Horticultural Traits in Theobroma cacao L.
Authors: Brown J. Steven , Phillips‐Mora Wilbert , Power Emilio J. , Krol Cheryl , Cervantes‐Martinez Cuauhtemoc , Motamayor Juan Carlos , Schnell Raymond J.
Published: September 2007

A heterozygous F1 mapping population of cacao (Theobroma cacao L.) was created and evaluated for resistance to frosty pod [caused by Moniliophthora roreri (Cif. and Par.) Evans et al.], and black pod [caused by Phytophthora palmivora (Butl.) Butl.] and for five horticultural traits at CATIE in Turrialba, Costa Rica. The population consisted of 256 F1 progeny from the cross ‘Pound 7’ × ‘UF 273’. Progeny were used to form a linkage map using 180 markers. The linkage map contained 10 linkage groups (LGs), numbered as the LG in the cacao reference map, and was used to locate putative quantitative trait loci (QTL) for resistance to the aforementioned diseases and five horticultural traits. Resistance to frosty pod was measured by internal and external pod resistance. Five QTLs for frosty pod resistance were found on three LGs, 2, 7, and 8, with UF 273 appearing to be the source of resistance. These alleles are being used for scoring progeny in ongoing cooperative marker‐assisted selection projects, and constitute the first QTLs identified for frosty pod resistance. Three QTLs for black pod resistance were found on LG 4, 8, and 10, with the most favorable alleles coming from Pound 7. One QTL was found on LG 4 for average trunk growth rate, and two QTLs for height of first jorquette were identified on LGs 4 and 6. One QTL each for average trunk diameter growth and pod color was found on LG 4.
Introgression of Resistance to Nematode Rotylenchulus reniformis into Upland Cotton (Gossypium hirsutum) from Gossypium longicalyx
Authors: Robinson A. F. , Bell A. A. , Dighe N. D. , Menz M. A. , Nichols R. L. , Stelly D. M.
Published: September 2007

Absence of sources of resistance to the reniform nematode, Rotylenchulus reniformis Linford & Oliveira, 1940, is a major impediment to the production of upland cotton (Gossypium hirsutum L.) in the USA. In this study, two trispecies hybrids of G. hirsutum, G. longicalyx J.B. Hutch. & B.J.S. Lee, and either G. armourianum Kearney or G. herbaceum L. were used as bridges to introgress high resistance to the nematode from G. longicalyx into G. hirsutum Introgression was accomplished by recurrent backcrosses to G. hirsutum with cytogenetic analysis of early backcross generations to assess progress toward the euploid state (2n = 52), selection for nematode resistance at each generation, and examination of self progeny at the first, third, sixth, and seventh backcross to identify and eliminate lineages with undesired recessive traits. Altogether, 689 BC1 progeny were generated from the two male‐sterile hybrids. Introgression was pursued from 28 resistant BC1 plants, each of which was backcrossed four to seven times to G. hirsutum to derive agronomically suitable types. The resistance trait segregated (resistant/susceptible) 1:1 in backcross progeny and 3:1 in self progeny. There was no obvious diminution of the resistance across backcross generations. Advanced backcross plants were indistinguishable from agronomic cotton under greenhouse conditions, and comparisons of 240 homozygous resistant BC6S2 plants with heterozygous, susceptible, and recurrent parent plants in field plantings in 2006 showed normal lint quality and quantity. The upcoming release of seed from this project is expected to provide the cotton industry with a major new tool for managing the reniform nematode in cotton, which costs U.S. producers about $100 million annually.
Effects of Two Major Fusarium Head Blight Resistance QTL Verified in a Winter Wheat Backcross Population
Authors: Häberle Jennifer , Schmolke Michael , Schweizer Günther , Korzun Viktor , Ebmeyer Erhard , Zimmermann Gerhard , Hartl Lorenz
Published: September 2007

Many Fusarium head blight (FHB) [caused by Fusarium graminearum Schw. and F. culmorum (W.G. Sm.) Sacc.] quantitative trait loci (QTL) have been detected in both spring and winter wheat (Triticum aestivum L.). However, a QTL validation has not been performed in winter wheat. We report on the verification of resistance QTL in winter wheat, which had been previously mapped in a Dream/Lynx population. The QTL intervals of chromosomes 7BS, 6AL, and 2BL were enriched with amplified fragment length polymorphism (AFLP) markers. For a more precise estimation of the QTL effects and their influence on plant height and heading date, BC2F4 lines were created by marker‐assisted selection and examined for FHB resistance. The phenotypic effects of the two main QTL on chromosomes 6AL and 7BS confirmed the previous results of the original mapping population. In the backcross population, QTL6AL and QTL7BS reduced FHB severity individually by 27% each relative to lines without resistance alleles. Both QTL had an effect on plant height, resulting in taller plants being more resistant. The combination of both QTL decreased disease severity most effectively (36%). The successfully validated QTL on chromosomes 6AL and 7BS are designated Qfhs.lfl-6AL and Qfhs.lfl-7BS, respectively. The best genotypes carried one or both of the major QTL, displaying their importance for disease resistance. In contrast to spring wheat, where QTL have been identified in an exotic genetic background, the resistance QTL validated in this study already reside in an adapted genetic background with excellent agronomic performance.
How Many Parents Give the Highest Yield in Predicted Synthetic and Composite Populations of Maize?
Authors: Kutka F. J. , Smith M. E.
Published: September 2007

Some U.S. farmers are still interested in open‐pollinated (OP) maize (Zea mays L.), but most varieties are low yielding. How would one develop high‐yielding OP varieties, and what are their commercial prospects? To answer this question, we analyzed data from published diallel experiments using Wright's equation. There were seven diallels with inbreds and 14 with populations. The number of inbreds needed to form high yielding synthetics was on average from five to eight lines. The highest predicted yields for composites were on average with three to seven populations. The potential of synthetics and composites as OP varieties in the USA has not been fully examined, though these would probably not be economical for grain in the U.S. Corn Belt. However, their yields may show improvement over current OP varieties and they may be commercially viable in some limited circumstances.
Developing Evaluation Methods for Kernel Shattering in Spring Wheat
Authors: Zhang Guorong , Mergoum Mohamed
Published: September 2007

Kernel shattering (KS) is known to cause yield loss in wheat (Triticum aestivum L.). The introduction of Fusarium head blight (caused by Fusarium graminearum Schwabe) resistant genotypes has recently elevated KS importance. This study aimed to identify appropriate methods to measure and evaluate KS variation among spring wheat genotypes. Four field and two laboratory methods were developed and compared using 24 wheat genotypes in five environments. Large variation for KS among genotypes was observed. The field kernel shattering method and the kernel shattering from spikes method (SS), both field methods, showed large CVs and were inconsistent across environments. Similarly, the direct yield loss method and the visual score method, also field methods, had relatively low range/LSD0.05 ratio values, leading to difficulty in discriminating between genotypes. Among the field methods, SS appears to be the most suitable method due to its high range/LSD0.05 values and fewer input requirements. All field methods, however, were time and labor consuming. The laboratory methods, induced random impact and glume strength, were moderately to strongly correlated with the field methods. The laboratory methods were more consistent across environments, and required only a small sample size. Hence, they were more effective and efficient in evaluating KS and could be of interest for wheat researchers to indirectly screen for KS resistance.
Maize Populations as Sources of Favorable Alleles to Improve Cold‐Tolerant Hybrids
Authors: Rodríguez V. M. , Malvar R. A. , Butrón A. , Ordás A. , Revilla P.
Published: September 2007

Low spring temperatures are one of the main limiting factors for maize (Zea mays L.) growth along the European Atlantic coast. Several breeding programs have been performed to obtain cold‐tolerant maize genotypes, but the few cold‐tolerant inbreds and hybrids available need further improvements for cold tolerance and agronomic performance. The objective of this study was to identify cold‐tolerant maize populations with favorable alleles to improve cold tolerance and agronomic performance in early sowing of two cold‐tolerant hybrids. The parental inbred lines of two cold‐tolerant hybrids were crossed to nine cold‐tolerant populations. Tests were performed in a cold chamber and in the field for 2 yr at two locations. The populations Rojo de Tolosa and Puenteareas were the most promising sources of new favorable alleles for transferring cold tolerance to the hybrids EP80 × F7 and EP80 × Z78007, respectively. The populations Puenteareas and Silver King were the most outstanding donors to improve the agronomic performance of EP80 × F7 and EP80 × Z78007, respectively. Some improved versions of the cold‐tolerant inbred parents could be developed from crosses between F7 or Z78007 and Puenteareas; alternatively, Rojo de Tolosa or Silver King could be used as donors of favorable alleles, but the simultaneous improvement of yield and cold tolerance is not straightforward.
Examining the testing effect with open‐ and closed‐book tests
Authors: Agarwal Pooja K. , Karpicke Jeffrey D. , Kang Sean H. K. , Roediger Henry L. , McDermott Kathleen B.
Published: September 2007

Two experiments examined the testing effect with open‐book tests, in which students view notes and textbooks while taking the test, and closed‐book tests, in which students take the test without viewing notes or textbooks. Subjects studied prose passages and then restudied or took an open‐ or closed‐book test. Taking either kind of test, with feedback, enhanced long‐term retention relative to conditions in which subjects restudied material or took a test without feedback. Open‐book testing led to better initial performance than closed‐book testing, but this benefit did not persist and both types of testing produced equivalent retention on a delayed test. Subjects predicted they would recall more after repeated studying, even though testing enhanced long‐term retention more than restudying. These experiments demonstrate that the testing effect occurs with both open‐ and closed‐book tests, and that subjects fail to predict the effectiveness of testing relative to studying in enhancing later recall. Copyright © 2007 John Wiley & Sons, Ltd.
Repetition and dual coding in procedural multimedia presentations
Authors: Brunyé Tad T. , Taylor Holly A. , Rapp David N.
Published: September 2007

Students learned toy assembly sequences presented in picture, text, or one of three multimedia formats, and completed order verification, recall, and object assembly tasks. Experiment 1 compared repetitious (i.e. dual format presentations each conveying similar information) with complementary (i.e. dual format presentations each conveying different information) multimedia presentations. Repetitious presentations appear to provide learning benefits as a function of their inherent redundancy; complementary presentations provide benefits as a result of users actively integrating picture and text elements into a cohesive mental model. Experiment 2 compared repetitious with interleaved (i.e. assembly steps presented in alternating picture‐text formats) multimedia presentations. Again, multimedia presentations led to overall learning advantages relative to single‐format presentations, with an emphasis on both repetition and integrative working memory processes. Object assembly performance consistently demonstrated the utility of picture learning, with or without accompanying text. Results are considered relative to classic and contemporary learning theory, and inform educational design. Copyright © 2007 John Wiley & Sons, Ltd.
Getting from neuron to checkmark: models and methods in cognitive survey research
Authors: Holleman Bregje C. , Murre Jaap M. J.
Published: September 2007

Since the 1980s much work has been done in the field of Cognitive Survey Research. In an interdisciplinary endeavour, survey methodologists and cognitive psychologists (as well as social psychologists and linguists) have worked to unravel the cognitive processes underlying survey responses: to improve survey measurement, but also to obtain fundamental insight into the process of question answering, the nature of attitudes, the functioning of human memory, etc. Yet, despite the amount of work that has been done, less progress has been made than was deemed possible. This paper suggests ways in which to develop cognitive theories that may help to obtain an integrated understanding of question answering in surveys. One way to build better theories is to focus on model construction. Different types of cognitive models are discussed that can be used to model question answering. Second, a larger variety of methods from the cognitive toolbox can be used to further develop and test these models. An overview is given of the various tools available to researchers of cognitive aspects of survey research, with a special focus on newer methods from cognitive neuroscience. To connect different tools and methods into an integrative theory of question answering, the idea of hierarchical modelling is proposed. Copyright © 2007 John Wiley & Sons, Ltd.
Chemisorption of carbon dioxide on sodium oxide promoted alumina
Authors: Lee K. B. , Beaver M. G. , Caram H. S. , Sircar S.
Published: September 2007

New equilibrium and column dynamic data for chemisorption of carbon dioxide from inert nitrogen at 250, 350, and 450°C were measured on a sample of sodium oxide promoted alumina, which was found to be a reversible chemisorbent for CO2. The equilibrium chemisorption isotherms were Langmuirian in the low pressure region (p <2.0 kPa) with a large gas–solid interaction parameter. The isotherms deviated from the Langmuirian behavior in the higher pressure region. A new analytical model which simultaneously accounted for Langmuirian chemisorption of CO2 on the adsorbent surface and additional reaction between the gaseous and sorbed CO2 molecules was used to describe the measured equilibrium data. The heats of CO2 chemisorption and the additional surface reaction were, respectively, 64.9 and 37.5 kJ/mol. The column breakthrough curves for CO2 sorption from inert N2 on the chemisorbent as well as the desorption of CO2 from the chemisorbent by N2 purge at 350°C could be described by the linear driving force (LDF) model in conjunction with the new sorption isotherm. The same LDF mass transfer coefficients can be used to describe both sorption and desorption processes. The CO2 mass transfer coefficients were (i) independent of feed gas CO2 concentration in the range of the data at a given temperature, and (ii) a weak function of temperature. The ratio of the mass transfer zone length to the column length was very small due to highly favorable CO2 sorption equilibrium. Several sequential cyclic CO2 sorption–desorption column dynamic tests were conducted to demonstrate the apparent stability of the material. © 2007 American Institute of Chemical Engineers AIChE J, 2007
Metatropic dysplasia: Clinical and radiographic findings in 11 patients demonstrating long‐term natural history
Authors: Kannu Peter , Aftimos Salim , Mayne Val , Donnan Leo , Savarirayan Ravi
Published: September 2007

We report on the largest long‐term follow‐up study in metatropic dysplasia incorporating data collected over a 37‐year period. Case summaries from 11 patients are presented, ranging from 20 weeks of gestation to age 70 years, characterizing the natural history. All patients were seen through the Victorian Clinical Genetics Service and the Southern Cross Bone Dysplasia Centre. Our data lend little support for the current clinical classification of metatropic dysplasia and highlight a spectrum of severity in this rare condition, which we propose has an autosomal dominant inheritance pattern. Complications such as upper respiratory obstruction secondary to laryngo‐tracheal dysfunction need to be carefully monitored for in infancy because this is a preventable cause of mortality. The progression of a thoracic kyphoscoliosis in this condition is often relentless and resistant to surgical treatment. Other causes of morbidity include cervical instability, hearing loss, and functional impairments resulting from degenerative joint deformity. Intellectual outcome in all surviving cases has been normal. Final adult heights ranged from 107 to 135 cm. © 2007 Wiley‐Liss, Inc.
Natal emigration by both sexes in the La Pacifica population of mantled howlers: when do some stay?
Authors: Clarke Margaret R. , Glander Kenneth E.
Published: September 2007

We have reported previously that all male and female mantled howlers emigrate from natal groups at Hacienda La Pacifica, Costa Rica. In the years since that report, a small number of juveniles have stayed in the natal group without experiencing a solitary phase. Here, we present a post hoc analysis on juvenile emigration in six groups of howlers under observation for varying amounts of time between 1972 and 2005. Our records revealed 139 juveniles for whom emigration status was certain, and 125 of these did emigrate. There was a significant association between presence of mother and emigration: juveniles without mothers were more likely to remain in their natal group (χ= 53.1,P<.0001). The mean age of emigration for all juveniles (n= 125) was 2.47 years (SD = 0.9, range = 1.5–6.5). There was no difference in age of emigration by adult male composition (one‐male, multi‐male, both), but juveniles of unknown sex emigrated younger than either known males or females (F2,116= 4.4,P<.02). For emigrating juveniles of known sex (n= 99), both males and females without mothers left at a later age than those with mothers (F1,95= 6.5,P<.02). Although philopatry or delayed emigration occurs in a few motherless animals, most males and females do emigrate from their natal groups at ages consistent with those reported for other species of howlers. Am. J. Primatol. 70:195–200, 2008. © 2007 Wiley‐Liss, Inc.
Pathological correlates of dementia in a longitudinal, population‐based sample of aging
Authors: Sonnen Joshua A. , Larson Eric B. , Crane Paul K. , Haneuse Sebastien , Li Ge , Schellenberg Gerald D. , Craft Suzanne , Leverenz James B. , Montine Thomas J.
Published: September 2007

Objective

Previously published community‐ or population‐based studies of brain aging and dementia with autopsy were restricted to a single sex, a single ethnic group, Roman Catholic clergy, or focused pathological assessments. Our goal was to determine the independent pathological correlates associated with dementia in a typical US population.

Methods

We evaluated autopsy data from the Adult Changes in Thought study, an ongoing longitudinal, population‐based study of brain aging and dementia. Analyses were based on data collected from about 3,400 people 65 years or older who were cognitively intact at the time of enrollment in the Group Health Cooperative in King County, Washington. All consecutive autopsies (n = 221; 20% of deaths) from this cohort were evaluated and analyzed by weighted multivariate analysis to account for potential participation bias.

Results

After adjusting for age, sex, education, and APOE, independent correlates of dementia (relative risk, 95% confidence interval; overall p value) included Braak stage (V/VI vs 0/I/II: 5.89, 1.62–17.60; p < 0.05), number of cerebral microinfarcts in standardized sections (>2 vs none: 4.80, 1.91–10.26; p < 0.001), and neocortical Lewy bodies (any vs none: 5.08, 1.37–18.96; p < 0.05). Estimates of adjusted population attributable risk for these three processes were 45% for Braak stage, 33% for microinfarcts, and 10% for neocortical Lewy bodies.

Interpretation

Our results underscore the therapeutic imperative for Alzheimer's and Lewy body diseases, and provide evidence to support the immediate use of strategies that target cerebral microinfarcts as a means to partially prevent or delay the onset of dementia. Ann Neurol 2007
Risk for symptomatic intracerebral hemorrhage after thrombolysis assessed by diffusion‐weighted magnetic resonance imaging
Authors: Singer Oliver C. , Humpich Marek C. , Fiehler Jens , Albers Gregory W. , Lansberg Maarten G. , Kastrup Andiras , Rovira Alex , Liebeskind David S. , Gass Achim , Rosso Charlotte , Derex Laurent , Kim Jong S. , Neumann‐Haefelin Tobias
Published: September 2007

Objective

The risk for symptomatic intracerebral hemorrhage (sICH) associated with thrombolytic treatment has not been evaluated in large studies using diffusion‐weighted imaging (DWI). Here, we investigated the relation between pretreatment DWI lesion size and the risk for sICH after thrombolysis.

Methods

In this retrospective multicenter study, prospectively collected data from 645 patients with anterior circulation stroke treated with intravenous or intraarterial thrombolysis within 6 hours (<3 hours: n = 320) after symptom onset were pooled. Patients were categorized according to the pretreatment DWI lesion size into three prespecified groups: small (≤10ml; n = 218), moderate (10–100ml; n = 371), and large (>100ml; n = 56) DWI lesions.

Results

In total, 44 (6.8%) patients experienced development of sICH. The sICH rate was significantly different between subgroups: 2.8, 7.8, and 16.1% in patients with small, moderate, and large DWI lesions, respectively (p < 0.05). This translates to a 5.8 (2.8)‐fold greater sICH risk for patients with large DWI lesions as compared with patients with small (or moderate) DWI lesions. The results were similar in the large subgroup (n = 536) of patients treated with intravenous tissue plasminogen activator. DWI lesion size remained an independent risk factor when including National Institutes of Health Stroke Scale, age, time to thrombolysis, and leukoariosis in a logistic regression analysis.

Interpretation

This multicenter study provides estimates of sICH risk in potential candidates for thrombolysis. The sICH risk increases gradually with increasing DWI lesion size, indicating that the potential benefit of therapy needs to be balanced carefully against the risk for sICH, especially in patients with large DWI lesions. Ann Neurol 2007
Generation of microcellular polyurethane with supercritical carbon dioxide
Authors: Ito Shunsuke , Matsunaga Katsuji , Tajima Masahiro , Yoshida Yasuhiko
Published: September 2007

We examined the formation of microcellular foam in a thermoplastic polyurethane elastomer (TPU) with supercritical carbon dioxide. Measurements of the permeability and impregnation with carbon dioxide suggested that the impregnation of TPU with carbon dioxide was affected by the soft‐segment chain length and soft‐segment concentration in TPU and that carbon dioxide was mainly present in the soft‐segment area. Thus, it seemed likely that the nucleation and growth of the nuclei in the microcells occurred in the soft‐segment area. In addition, scanning electron microscopy of the microcells indicated that the higher the saturation pressure was, the smaller the mean cell diameter was; that is, the higher the cell number density was, the lower the foaming temperature was, the smaller the mean cell diameter was, and the lower the saturation pressure was, the more conspicuous this phenomenon was. These results showed that the saturation pressure and foaming temperature affected the cell structure. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007
Moisture permeability through multilayered barrier films as applied to flexible OLED display
Authors: Greener J. , Ng K. C. , Vaeth K. M. , Smith T. M.
Published: September 2007

Strict protection of organic light‐emitting diodes (OLEDs) and other optoelectronic materials from direct contact with ambient moisture and oxygen is one of the major challenges in the development of flexible OLED displays and other flexible electronic devices. This problem is typically addressed by the use of polymeric substrates with multilayered barrier coatings comprising alternating organic/inorganic layers. The multilayered barrier approach is critically examined using a numerical model based on a defect‐dominated diffusion process combined with experiments involving face‐to‐face lamination of two barrier films. The modeling results identify two regimes, corresponding to two distinct permeation mechanisms, and provide scaling relationships and general design criteria for multilayered barrier coatings. The results suggest that the most significant gain in barrier performance can be realized when the thickness of the organic/adhesive layer(s) in the multilayered structure is less than the average pinhole (defect) size in the inorganic barrier layer(s). © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007
Kinetics of oil palm empty fruit bunch phenolysis in the presence of sulfuric acid as a catalyst
Authors: Ahmadzadeh Ali , Zakaria Sarani
Published: September 2007

Oil palm empty fruit bunch (EFB) was successfully phenolyzed in the presence of sulfuric acid as a catalyst at different temperatures, reaction times, and percentage of catalyst used. Sulfuric acid was used as catalyst (5 and 8%) at the reacting temperature of 110–150°C with various reaction times. The kinetics parameters along with the weight of reacted EFB and phenol were calculated using the second‐ and third‐order reaction kinetics models. The weight of the reacted EFB in phenol shows that about 97% of EFB was liquefied during the reaction. However, only 70% of phenol was reacted with EFB. The kinetic studies showed that the EFB phenolysis in the presence of sulfuric acid followed a bimolecular type of the second‐order reaction. The activation energy calculated from the Arrhenius equation was 50.7 and 18.06 kJ/mol when the catalyst concentration was 5 and 8%, respectively. It can be depicted that the activation energy decreased as the catalyst increased. The reaction enthalpy showed that the liquefaction of EFB in phenol had dominantly followed the endothermic reaction. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007
Enhanced thermal conductivity of boron nitride epoxy‐matrix composite through multi‐modal particle size mixing
Authors: Yung K. C. , Liem H.
Published: September 2007

Castable particulate‐filled epoxy resins exhibiting excellent thermal conductivity have been prepared using hexagonal boron nitride (hBN) and cubic boron nitride (cBN) as fillers. The thermal conductivity of boron nitride filled epoxy matrix composites was enhanced up to 217% through silane surface treatment of fillers and multi‐modal particle size mixing (two different hBN particle sizes and one cBN particle size) prior to fabricating the composite. The measurements and interpretation of the curing kinetics of anhydride cured epoxies as continuous matrix, loaded with BN having multi‐modal particle size distribution, as heat conductive fillers, are highlighted. This study evidences the importance of surface engineering and multi‐modal mixing distribution applied in inorganic fillered epoxy‐matrix composite. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007
Copolymerization of N‐(4‐bromophenyl)‐2‐methacrylamide with n‐butyl methacrylate: Synthesis, characterization and monomer reactivity ratios
Authors: Delibaş Ali , Soykan Cengiz
Published: September 2007

The monomer, N‐(4‐bromophenyl)‐2‐methacrylamide (BrPMAAm) has been synthesized by reacting 4‐bromoaniline with methacryloyl chloride in the presence of triethylamine (NR3) at 0−5°C. Copolymerization of BrPMAAm with n‐butyl methacrylate (n‐BMA) has been carried out in 1,4‐dioxane by free radical solution polymerization at (70 ± 0.1)°C utilizing 2,2′‐azobisisobutyronitrile (AIBN) as an initiator in different in‐feed ratios. The composition of the copolymer was determined by the elemental analysis. The comonomer reactivity ratios determined by Fineman‐Ross (FR), Kelen‐Tüdös (KT), and extended Kelen‐Tüdös (EKT) methods. The copolymers were characterized by FTIR, 1H‐, and 13C NMR spectroscopic technique. Gel permeation chromatography was employed for estimating the weight–average (Mw) and number–average (Mn) molecular weights and polydispersity index (PDI) of the copolymers. Glass transition temperatures (Tg) were determined by differential scanning calorimetry and found to be characteristic of copolymer composition. As the N‐(4‐bromophenyl)‐2‐methacrylamide content increases, the Tg increases from 339 to 437 K. Thermal stabilities of the homo‐ and copolymers were calculated using thermogravimetric analysis. Thermally stable copolymers were obtained by the incorporation of BrPMAAm units as the initial decomposition temperature of the copolymers increased with the increase in concentration of BrPMAAm units. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Moisture absorption by various polyamides and their associated dimensional changes
Authors: Monson L. , Braunwarth M. , Extrand C. W.
Published: September 2007

The dimensional changes associated with moisture absorption were examined for various polyamides (PAs). Plaques of varying thickness were compression‐molded or injection‐molded and then immersed in water. Periodically, the plaques were removed from water and their mass and dimensions were measured. This was continued until they were completely saturated. The more polar PA46 absorbed more water than less polar PA6 and PA66 and therefore, was more susceptible to moisture‐induced dimensional growth. For a given polymer, it was found that the thicker samples took longer to reach saturation, but had the same diffusion coefficient as thinner ones. Changes in dimensions coincided with changes in mass. Sorption and swelling followed slightly different paths, but arrived at their respective equilibrium values at the same time. Within experimental error, dimensional expansion due to water absorption was the same in all directions. Injection‐molded samples absorbed slightly more water than compression‐molded ones, but their absorption rates were equal. Equilibrium water absorption data were used to approximate the dimensional changes associated with the swelling of the PAs. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Processibility and mechanical properties of micronized polytetrafluoroethylene reinforced silicone rubber composites
Authors: Park Eun‐Soo
Published: September 2007

Various micronized polytetrafluoroethylene (PTFE) powders were compounded with silicone rubber (MQ) and mechanical properties of the MQ/PTFE composites were evaluated. The fracture surface morphologies of prepared composites were also investigated using scanning electron microscopy (SEM). At a level of only 5 wt %, the fractured surface of MQ/PTFE composites show layered structure morphology. This structure effectively improves the tear strength of MQ but it also led to lower the tensile properties of the composites. The addition of fluorosilicone rubber (FMQ) as compatibilizer, tensile and tear strength of the composites improved considerably. However, tensile properties of the MQ/solution of sodium in liquid ammonia treated PTFE composite decreased compared with those of the untreated one. To investigate the production potential of extrusion process, an electric wire was extruded with MQ/PTFE/FMQ composites. During the curing process, volatile molecules lead to bubble and void formation of extruded layer depending on the filler shapes. The spherical PTFE powder was suitable for extrusion process. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Condition assessment of lamprey populations in the Yorkshire Ouse catchment, north‐east England, and the potential influence of physical migration barriers
Authors: Nunn A.D. , Harvey J.P. , Noble R.A.A. , Cowx I.G.
Published: September 2007

River lamprey (Lampetra fluviatilis) and sea lamprey (Petromyzon marinus) are designated features of the River Derwent Special Area of Conservation (SAC) and the Humber Estuary (a possible SAC). This study determined the condition of lamprey populations in the Yorkshire Ouse catchment by assessing the species composition, distribution, abundance and size‐structure of larval (ammocoete) populations in five major tributary rivers (Derwent, Swale, Ure, Nidd and Wharfe).

According to EU condition assessment criteria, Lampetra populations (assumed to be mostly river lamprey) are at present in favourable condition, with site mean (±SE) densities ranging from 2.7 (±1.2) to 160.3 (±50.5) individuals m−2 (all river means >2 individuals m−2), and at least two size (≈age) classes present in optimal microhabitats. By contrast, no sea lamprey larvae were recorded, suggesting that populations of this species are in unfavourable condition.

Actions to protect and enhance nationally or internationally important stocks must be implemented from at least a catchment perspective, because many of the issues affecting such species are not localized. With respect to lampreys, particular attention should be given to protecting spawning and nursery habitats, improving water quality, reducing impingement at abstraction points, preventing exploitation at spawning grounds and increasing passage at potential physical obstructions.

Copyright © 2007 John Wiley & Sons, Ltd.
Information source horizons and source preferences of environmental activists: A social phenomenological approach
Authors: Savolainen Reijo
Published: September 2007

This study focuses on the ways in which people define their source preferences in the context of seeking orienting information for nonwork purposes. The conceptual framework of the study combines ideas drawn from social phenomenology and information‐seeking studies. The study utilizes Alfred Schutz's model describing the ways in which actors structure everyday knowledge into regions of decreasing relevance. It is assumed that this structuring based on the actor's interest at hand is also reflected in the ways in which an actor prefers information sources and channels. The concept of information source horizon is used to elicit articulations of source preferences. The empirical part of the study draws on interviews with 20 individuals active in environmental issues. Printed media (newspapers), the Internet, and broadcast media (radio, television) were preferred in seeking for orienting information. The major source preferences were content of information, and availability and accessibility. Usability of information sources, user characteristics such as media habits, and situational factors were mentioned less frequently as preference criteria.
Manifestation of research teams in journal literature: A growth model of papers, authors, collaboration, coauthorship, weak ties, and Lotka's law
Authors: Morris Steven A. , Goldstein Michel L.
Published: September 2007

This article introduces a team‐based model of researchers in a specialty and investigates the manifestation of such teams in a specialty's literature. The proposed qualitative behavioral model, with its mathematical expression as a growth model, is significant because it simultaneously describes the two phenomena of collaboration and author productivity (Lotka's law) in a specialty. The model is nested: A team process models the creation of research teams and the success‐breeds‐success process of their production of articles, while at a lower level the productivity of authors within teams is also modeled as a success‐breeds‐success process. Interteam collaboration (weak ties) is modeled as random events. This simple growth model is shown to faithfully mimic six network metrics of bipartite article‐author networks. The model is demonstrated on three example article collections from specialties that have a wide range of degree of collaboration: (a) a distance education collection with low collaboration degree, (b) a complex networks collection with typical collaboration degree, and (c) an atrial ablation collection with heavy collaboration degree.
Description and search labor for information retrieval
Authors: Warner Julian
Published: September 2007

Selection power is taken as the fundamental value for information retrieval systems. Selection power is regarded as produced by selection labor, which itself separates historically into description and search labor. As forms of mental labor, description and search labor participate in the conditions for labor and for mental labor. Concepts and distinctions applicable to physical and mental labor are indicated, including the necessity of labor for survival, the idea of technology as a human construction, and the possibility of the transfer of human labor to technology. Distinctions specific to mental labor, particularly between semantic and syntactic labor, are introduced. Description labor is exemplified by cataloging, classification, and database description, can be more formally understood as the labor involved in the transformation of objects for description into searchable descriptions, and is also understood to include interpretation. The costs of description labor are discussed. Search labor is conceived as the labor expended in searching systems. For both description and search labor, there has been a progressive reduction in direct human labor, with its syntactic aspects transferred to technology, effectively compelled by the high relative costs of direct human labor compared to machine processes.
Dispersive shock waves in the solar wind
Authors: Ballai I. , Forgács‐Dajka E. , Marcu A.
Published: September 2007

Compressional waves in the solar wind propagating over large distances are likely to steepen into shock waves where the increase in the amplitude is balanced by dissipation. Dispersive effects caused by, e.g. Hall currents perpendicular to the ambient magnetic field can influence the generation and propagation of shock waves. In the present study the dispersion is considered weak but in time its importance can grow. When the effect of dispersion is strong enough, it can balance the nonlinear steepening of waves leading to the formation of solitons. The obtained results show that the weak dispersion will alter the amplitude and propagation speed of the shock wave. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
On transition region convection cells in simulations of p‐mode propagation into the solar atmosphere
Authors: Malins C.
Published: September 2007

This paper examines the way that transition region surface waves, generated in 2‐D numerical simulations of the nonmagnetic solar atmosphere when various synthetic photospheric drivers are applied, drive the granulation of the transition region/lower coronal region into convection cells. It is shown that these cells are generated by both synthetic point drivers and synthetic horizontally coherent p‐mode drivers. These cells cause the conversion of driven signals in vertical velocity into coronal signals predominantly in horizontal velocity, which if carried over to a case with a magnetic field included could cause mode conversion. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
MHD waves at a spherical interface modelling EIT waves
Authors: Douglas M. , Ballai I.
Published: September 2007

Eruptive events such as flares and coronal mass ejections (CMEs) are known to generate global waves propagating over distances comparable to the solar radius in different layers of the solar atmosphere. Here we investigate the propagation of coronal EIT waves, modelled as fast magnetoacoustic modes propagating at a spherical interface in the presence of a purely radial magnetic field. Based on a simplified equilibrium we derive the dispersion relation of the waves. The generation and propagation of EIT waves at the spherical interface is studied numerically for different values of spherical degree and preliminary conclusions are reached regarding the properties of EIT waves. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Are extrasolar oceans common throughout the Galaxy?
Authors: Ehrenreich D. , Cassan A.
Published: September 2007

Light and cold extrasolar planets such as OGLE 2005‐BLG‐390Lb, a 5.5 Earth masses planet detected via microlensing, could be frequent in the Galaxy according to some preliminary results from microlensing experiments. These planets can be frozen rocky‐ or ocean‐planet, situated beyond the snow line and, therefore, beyond the habitable zone of their system. They can nonetheless host a layer of liquid water, heated by radiogenic energy, underneath an ice shell surface for billions of years, before freezing completely. These results suggest that oceans under ice, like those suspected to be present on icy moons in the Solar system, could be a common feature of cold low‐mass extrasolar planets. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
The structure of the extended phase space of the Sitnikov problem
Authors: Kovács T. , Érdi B.
Published: September 2007

The extended phase space of the Sitnikov problem is studied by using a stroboscopic map and computing escape times. Comparisons of phase portraits and plots of escape times reveal the intrinsic connection between the geometry of the phase space and the dynamical behaviour of the system. Properties of the phase space are analysed both in the central regular region and far from it. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Results of the photometry of the spotted dM1‐2e star EY Draconis
Authors: Vida K.
Published: September 2007

We have observed EY Draconis with the 60‐cm telescope of Konkoly Observatory in Budapest for 64 nights. In the first observing season the star produced a stable light curve for more than 60 stellar rotations, however, the light curves observed in the next season and the spot modelling show clear evidence of the evolution of the spotted stellar surface. The changes of the maximum brightness level suggests the existence of a longer period of about 300 days, which seems to be confirmed by the ROTSE archival data. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Heating of the solar and stellar coronae: a review
Authors: Erdélyi R. , Ballai I.
Published: September 2007

Despite great advances in observations and modelling, the problem of solar and stellar heating still remains one of the most challenging problems of space physics. To find a definite answer to what sort of mechanisms act to heat the plasma to a few million degrees requires a collaborative effort of small scales observations, large capacity numerical modelling and complicated theoretical approaches. A unique theory should incorporate aspects such as the generation of energy, its transport and dissipation. Up to now, the first two problems are rather clarified. However, the modality of transfer of magnetic or kinetic energy into heat is a question still awaiting for an answer. In the present paper we review the various popular heating mechanisms put forward in the existing extensive literature. The heating processes are, somewhat arbitrarily, classified as hydrodynamic, magnetohydrodynamic or kinetic based on the characteristics of the model medium. These mechanisms are further divided based on the time scales of the ultimate dissipation involved (i.e. AC and DC heating, turbulent heating). In particular, special attention is paid to discuss shock dissipation, mode coupling, resonant absorption, phase mixing, and, reconnection. Finally, we briefly review the various heating mechanisms proposed to heat other stars. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
On the possibility of a bimodal solar dynamo
Authors: Petrovay K.
Published: September 2007

A simple way to couple an interface dynamo model to a fast tachocline model is presented, under the assumption that the dynamo saturation is due to a quadratic process and that the effect of finite shear layer thickness on the dynamo wave frequency is analogous to the effect of finite water depth on surface gravity waves. The model contains one free parameter which is fixed by the requirement that a solution should reproduce the helioseismically determined thickness of the tachocline. In this case it is found that, in addition to this solution, another steady solution exists, characterized by a four times thicker tachocline and 4–5 times weaker magnetic fields. It is tempting to relate the existence of this second solution to the occurrence of grand minima in solar activity. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)