bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Pivotal Roles of the Plant S-Adenosylmethionine Decarboxylase 5′ Untranslated Leader Sequence in Regulation of Gene Expression at the Transcriptional and Posttranscriptional Levels
Authors: Hu Wen-Wei , Gong Haibiao , Pua Eng Chong 
Published: April 2005

Abstract
S-Adenosylmethionine decarboxylase (SAMDC; EC 4.1.1.50) is a key rate-limiting enzyme located in the polyamine biosynthesis pathway. When compared with other organisms, the plant SAMDC genes possess some distinct features because they are devoid of introns in the main open reading frame (ORF) but have an intron(s) in their 5′ untranslated leader sequences, in which two overlapping tiny and small upstream ORFs (uORFs) are present. Our results show that the presence of the 5′ leader sequence plays important roles in transcriptional and posttranscriptional regulation of SAMDC expression. This sequence may help to keep the transcript of its downstream cistron at a relatively low level and function together with its own promoter in response to external stimuli or internal changes of spermidine and spermine to initiate and regulate SAMDC expression. Under stress and high spermidine or spermine conditions, the tiny uORF shows the same function as its overlapping small uORF, which is involved in translational repression and feedback controlled by polyamines. The presence of introns is necessary for the SAMDC up-regulation process when the internal spermidine level is low. Our results suggest that plants have evolved one network to adjust SAMDC activity through their 5′ leader sequences, through which transcriptional regulation is combined with an extensive posttranscriptional control circuit.
A Stilbene Synthase Gene (SbSTS1) Is Involved in Host and Nonhost Defense Responses in Sorghum
Authors: Yu Christine K.Y. , Springob Karin , Schmidt Jürgen , Nicholson Ralph L. , Chu Ivan K. , Yip Wing Kin , Lo Clive 
Published: April 2005

Abstract
A chalcone synthase (CHS)-like gene, SbCHS8, with high expressed sequence tag abundance in a pathogen-induced cDNA library, was identified previously in sorghum (Sorghum bicolor). Genomic Southern analysis revealed that SbCHS8 represents a single-copy gene. SbCHS8 expression was induced in sorghum mesocotyls following inoculation with Cochliobolus heterotrophus and Colletotrichum sublineolum, corresponding to nonhost and host defense responses, respectively. However, the induction was delayed by approximately 24 h when compared to the expression of at least one of the other SbCHS genes. In addition, SbCHS8 expression was not induced by light and did not occur in a tissue-specific manner. SbCHS8, together with SbCHS2, was overexpressed in transgenic Arabidopsis (Arabidopsis thaliana) tt4 (transparent testa) mutants defective in CHS activities. SbCHS2 rescued the ability of these mutants to accumulate flavonoids in seed coats and seedlings. In contrast, SbCHS8 failed to complement the mutation, suggesting that the encoded enzyme does not function as a CHS. To elucidate their biochemical functions, recombinant proteins were assayed with different phenylpropanoid-Coenzyme A esters. Flavanones and stilbenes were detected in the reaction products of SbCHS2 and SbCHS8, respectively. Taken together, our data demonstrated that SbCHS2 encodes a typical CHS that synthesizes naringenin chalcone, which is necessary for the formation of different flavonoid metabolites. On the other hand, SbCHS8, now retermed SbSTS1, encodes an enzyme with stilbene synthase activity, suggesting that sorghum accumulates stilbene-derived defense metabolites in addition to the well-characterized 3-deoxyanthocyanidin phytoalexins.
Morphological variations in the pre‐imaginal development of the ponerine antDiacamma ceylonense
Authors: Baratte Sébastien , Cobb Matthew , Deutsch Jean , Peeters Christian 
Published: April 2005

AbstractIn the present paper, the larval development of the queenless ponerine antDiacamma ceylonenseis studied. Four instars were identified on the basis of cuticular processes – tubercles and spinules – which show discontinuous variation during growth and provide precise and reliable external morphological criteria for instar discrimination. In the first three instars, the larva possesses a striking proboscis, which disappears between the third and fourth instars. Larval weight increased around 50‐fold in the 21 days of larval life between eclosion and pupation (mean weight for first instar = 0.37 mg; for fourth instar = 20 mg). In addition, the morphology of the gemmae, structures resembling vestigial wings in workers, is described in nymphae.
Relationship‐based practice and reflective practice: holistic approaches to contemporary child care social work
Authors: Ruch Gillian 
Published: April 2005

ABSTRACTThe renewed interest in relationship‐based practice can be understood in the child care social work context as a response to the call to re‐focus practice in this field. Relationship‐based practice challenges the prevailing trends which emphasize reductionist understandings of human behaviour and narrowly conceived bureaucratic responses to complex problems. In so doing practitioners engaged in relationship‐based practice need to be able to cope with the uniqueness of each individual's circumstances and the diverse knowledge sources required to make sense of complex, unpredictable problems. This paper argues that if relationship‐based practice is to become an established and effective approach to practice, practitioners need to develop their reflective capabilities. An outline of contemporary understandings of relationship‐based and reflective practice is offered and findings from doctoral research drawn on to identify how reflective practice complements relationship‐based practice. The product of this complementary relationship is enhanced understandings across four aspects of practice: the client, the professional self, the organizational context and the knowledges informing practice. The paper concludes by acknowledging the inextricably interconnected nature of relationship‐based and reflective practice and emphasizes the importance of practitioners being afforded opportunities to practise in relational and reflective ways.
Growth of Geobacter sulfurreducens under nutrient‐limiting conditions in continuous culture
Authors: Esteve‐Núñez Abraham , Rothermich Mary , Sharma Manju , Lovley Derek 
Published: April 2005

SummaryA system for growing Geobacter sulfurreducens under anaerobic conditions in chemostats was developed in order to study the physiology of this organism under conditions that might more closely approximate those found in the subsurface than batch cultures. Geobacter sulfurreducens could be cultured under acetate‐limiting conditions with fumarate or Fe(III)‐citrate as the electron acceptor at growth rates between 0.04 and 0.09 h−1. The molar growth yield was threefold higher with fumarate as the electron acceptor than with Fe(III), despite the lower mid‐point potential of the fumarate/succinate redox couple. When growth was limited by availability of fumarate, high steady‐state concentrations were detected, suggesting that fumarate is unlikely to be an important electron acceptor in sedimentary environments. The half‐saturation constant, Ks, for acetate in Fe(III)‐grown cultures (10 µM) suggested that the growth of Geobacter species is likely to be acetate limited in most subsurface sediments, but that when millimolar quantities of acetate are added to the subsurface in order to promote the growth of Geobacter for bioremediation applications, this should be enough to overcome any acetate limitations. When the availability of electron acceptors, rather than acetate, limited growth, G. sulfurreducens was less efficient in incorporating acetate into biomass but had higher respiration rates, a desirable physiological characteristic when adding acetate to stimulate the activity of Geobacter species during in situ uranium bioremediation. These results demonstrate that the ability to study the growth of G. sulfurreducens under steady‐state conditions can provide insights into its physiological characteristics that have relevance for its activity in a diversity of sedimentary environments.
Diversity of Bacteria and Archaea associated with a carbonate‐rich metalliferous sediment sample from the Rainbow vent field on the Mid‐Atlantic Ridge
Authors: Nercessian Olivier , Fouquet Yves , Pierre Catherine , Prieur Daniel , Jeanthon Christian 
Published: April 2005

SummaryTwo sediment cores were collected in an inactive area of the deep‐sea hydrothermal vent field Rainbow (36°N on the Mid‐Atlantic Ridge). Metals and carbonates were abundant throughout the cores; calcite (CaCO3) was found throughout the cores while dolomite [CaMg(CO3)2] and siderite (FeCO3) were only found in deeper layers. Using polymerase chain reaction (PCR)‐amplified 16S rRNA gene sequence analysis, we examined the bacterial and archaeal diversity in a sediment layer that contained the three carbonates. The retrieved bacterial and archaeal sequences were new and less than 4% of the sequences exhibited 94% or more identity with that of cultured organisms. The analysis of the composition of the bacterial library  revealed  a  high  diversity  of  sequences.  Half of the bacterial clones was affiliated to the γ‐Proteobacteria. Most of them had environmental sequences retrieved from deep‐sea sediments as closest relatives, some of which being distantly related to free‐living and symbiotic sulfur‐oxidizers. Other sequences clustered in the α‐, δ‐ and ɛ‐Proteobacteria, the ‘Bacteroidetes’, the ‘Planctomycetes’, the ‘Nitrospirae’, the ‘Actinobacteria’, the ‘Chlorobi ’ and the ‘Verrumicrobia’. Based on clonal abundance and sequence comparisons, phylotype groups putatively involved in the oxydation of sulfur compounds appeared to dominate in the studied sample. The majority of the archaeal sequences clustered in an euryarchaeotic lineage recently identified in the walls of black smokers suggesting a possible thermophilic way of life of these uncultured microorganisms. Oxygen isotopic composition of siderite and dolomite indicated that they were formed at 67°C and 94°C respectively. Together with chemical and microbiological data, this suggested that hydrothermal fluids may have circulated through this sediment.
A cross‐sectional behavioral genetic analysis of task persistence in the transition to middle childhood
Authors: Deater‐Deckard Kirby , Petrill Stephen A. , Thompson Lee A. , DeThorne Laura S. 
Published: April 2005

Abstract Task persistence, measured by a composite score of independent teacher, tester and observer reports, was examined using behavioral genetic analysis. Participants included 92 monozygotic and 137 same‐sex dizygotic twin pairs in Kindergarten or 1st grade (4.3 to 7.9 years old). Task persistence was widely distributed, higher among older children, positively associated with standardized tests of cognitive performance and achievement, and negatively associated with parents’, teachers’ and observers’ reports of behavioral problems. Cross‐sectional analysis indicated a strong developmental shift from shared environment variance among younger children to additive genetic variance in older children.
Localizing cortical sources of event‐related potentials in infants’ covert orienting
Authors: Richards John E. 
Published: April 2005

Abstract This study used cortical source analysis to locate potential cortical sources of event‐related potentials (ERPs) during covert orienting in infants aged 14 and 20 weeks. The infants were tested in a spatial cueing procedure. The reaction time to localize the target showed response facilitation for valid trials relative to invalid or neutral trials. High‐density EEG (126 channels) was recorded during the task, and independent component analysis and equivalent current dipole analysis was used to estimate the cortical sources of the EEG during the task. There was a larger P1 ERP component on the valid trials than the other trials (P1 validity effect). The cortical source analysis suggested that this occurred due to activity in Brodmann's areas 18 and 19. A presaccadic ERP component occurred over the frontal scalp areas (−65 ms) and was larger to a target in a cued location than in uncued locations. A potential cortical source for this ERP component was the superior frontal gyrus on the inferior portion of the prefrontal cortex. Increases from 14 to 20 weeks in amplitude of the P1 validity effect and the presaccadic ERP could be modeled by an increase in activation in the corresponding cortical areas.
Forming a stable memory representation in the first year of life: why imitation is more than child's play
Authors: Lukowski Angela F. , Wiebe Sandra A. , Haight Jennifer C. , DeBoer Tracy , Nelson Charles A. , Bauer Patricia J. 
Published: April 2005

AbstractAlthough 9‐month‐old infants are capable of retaining temporally ordered information over long delays, this ability is relatively fragile. It may be possible to facilitate long‐term retention by allowing infants to imitate event sequences immediately after their presentation. The effects of imitation on immediate and delayed recognition and on long‐term recall were investigated using event‐related potentials (ERPs) and elicited imitation, respectively. Mnemonic facilitation resulting from the opportunity to imitate was apparent using both assessments. ERP assessments at immediate and delayed recognition tests suggested that infants who were allowed to imitate had stronger memory representations of familiar stimuli relative to infants who only viewed the presentation of the events. In addition, infants who were allowed to imitate evidenced higher levels of ordered recall after 1 month relative to infants who only watched the experimenter's demonstration. Therefore, imitation proved to have beneficial effects on explicit memory in 9½‐month‐olds, providing evidence of its effectiveness as a tool to augment mnemonic capabilities in infancy.
PRINClPLES IN THE VALUATION OF HUMAN CAPITAL
Authors: Bowman Mary Jean 
Published: April 2005

Human capital concepts and measures have been applied and misapplied to an increasing variety of economic problem areas, two of which are examined.One of these is measurement of human capital gains and losses through migration. First requirements here are specification of the gaining or losing entities and of the relevant welfare functions. Alternatives in these respects are outlined. It is then argued that an appropriately adapted Fisherian present‐value assessment of human capital is normally the correct measure. Replacement costs are a legitimate substitute only for young migrants with little cumulated learning through experience and even then they have usually been fallaciously applied. Probability adjustments for migration and re‐migration are required in both cost and present‐value assessments of human capital effects of migration‐relevant policy alternatives, but the nature of those adjustments differs with the measurement approach used.For longitudinal analysis of contributions of human capital to economic growth, all measures of human capital stocks are inappropriate. A first principle of such analysis is measurement of resource inputs as flows. A coordinate principle requires that disaggregation be carried as far as necessary to distinguish essentially homogeneous categories of labor inputs. Though a way of separating out the schooling versus on‐the‐job‐experience components of human capital is illustrated, it requires some strong assumptions. Splitting men into abstracted human capital components is better avoided in growth analysis. Furthermore, categorization of labor‐force sub‐groups could equally well provide the basis for rate‐of‐return assessments of marginal changes in the pace of investments in humans. Such assessments would incorporate the main elements of capital theory except valuation of the capital asset itself.Ultimately, human resource measurements for use in major public policy decisions relating to either growth or migration (or both) must incorporate modifications or error components that allow for development phenomena that elude marginal assessments. Among developing countries especially, a consideration of educational diffusion processes and dynamic productivity scale effects, for example, could have critical measurement and policy implications.
OUTPUT AND PRICES IN THE INTERNATIONAL COMPARISON PROJECT*
Authors: Kravis Irving B. , Kenessey Zoltan 
Published: April 2005

In this paper we discuss a few of the problems that have been encountered in defining output and in comparing prices for the International Comparison Project (ICP). We report also on the way in which these problems are being met.The ICP has for its purpose the establishment of a systematic set of procedures for making international comparisons of gross domestic product (GDP) and of the purchasing power of currencies. Substantive work on comparisons involving Colombia, the European Economic Community (EEC), Hungary, India, Japan, Kenya, the United Kingdom and the United States is also being carried on with the aid of the statistical services of the countries and of the EEC. It is hoped to expand the comparisons beyond these countries as rapidly as possible.
SIZE‐DISTRIBUTION OF EARNINGS AND HOUSEHOLD INCOMES IN SMALL SOCIALIST COUNTRIES
Authors: Michal Jan M. 
Published: April 2005

Part I: Availability and meaning of East European distributional statistics are discussed. Part II: Measures of inequality to be used in this study are examined: the Gini coefficient of concentration, though superior to some other single indicators, is found to be an unreliable comparative measure of inequality, and is therefore supplemented by a set of ratios of selected percentiles to the median. Part III: Inequality of full‐time gross monthly earnings is measured for (almost) the whole civilian working population and for some subpopulations (selected industries, men, women) in Czechoslovakia and Yugoslavia through 1970, in Hungary through 1968: the observed inequality appears to be less than in small capitalist countries, in spite of the reversal of the socialist egalitarian trend in the 'sixties. The main factor of equalization of socialist earnings are small interoccupational and interregional differentials and a very flat age profile. Part IV: The socio‐economic structure of households, the size of samples underlying the distributional statistics, and the composition of household “revenues” (wage and salary earnings, agricultural incomes, social security payments, relatively unimportant property incomes, as well as non‐income cash flows) are examined. Inequality coefficients are estimated for per capita revenues of all households as well as subpopulations of households in Czechoslovakia and Hungary, and some information is given on the distribution of household incomes in Yugoslavia. Part V: Limits of desirable equalization of earnings are discussed. With very narrowly dispersed short‐term earnings, lifetime earnings tend to be rather unequally distributed because of the variation of earning years among occupations. With largely equalized primary incomes, per capita household incomes tend to be more unequally distributed, in spite of massive transfers, because of the varying ratio of earners to dependents within households. The need of income differentials as incentives to work, the probable trade‐off between income equality and economic growth, and socialist distributive principles are outlined.
HOUSEHOLD PRODUCTION AND NATIONAL PRODUCTION: AN IMPROVEMENT OF THE RECORD
Authors: Weinrobe Maurice 
Published: April 2005

Man may work from sun to sun, But woman's work is never done. Anon.
It has become almost a cliché that measured growth in the U.S. is being overstated. The classic on the subject is by Mishan [5], who argues persuasively that the (uncounted) externalities from production in industrialized economies are overtaking the production which these economies are counting. But externalities are not the only problems in measuring economic activity and economic growth. Two other problems of equal importance, but more amenable to measurement, are the distinction between final and intermediate production, and the quantification of nonmarket productive behavior. In this paper, we concentrate on one aspect of the measurement of nonmarket behavior—the value of production at home by housewives.1Specifically, we will present estimates of the value of home based nonmarket production by housewives. These estimates will then be used to supplement various national product aggregates in order to calculate more accurate growth rates for the U.S. economy. We find that the value of nonmarket production by married women during the 1960's has averaged approximately thirty percent of the GNP and close to 40 percent of the national income. The inclusion of the nonmarket work of housewives in GNP would reduce the measured rate of growth of real GNP per potential worker by about ten percent, the exact amount depending on how the value of nonmarket work is estimated. Our estimates indicate a reduction in the absolute rate of growth of almost 0.25 percent.
MANAGERIAL INCENTIVES AND CORPORATE DIVERSIFICATION STRATEGIES
Authors: Denis David J. , Denis Diane K. , Sarin Atulya 
Published: April 2005

Because the break‐up of conglomerates typically produces substantial increases in shareholder wealth, many commentators have argued that the conglomerate form of organization is inefficient. This article reports the findings of a number of recent academic studies, including the authors' own, that examine the causes and consequences of corporate diversification.Although theoretical arguments suggest that corporate diversification can have benefits as well as costs, several studies have documented that diversified firms trade at a significant discount from their single‐segment peers. Estimates of this discount range from 10–15% of firm value, and are larger for “unrelated” diversification than for “related” diversification.If corporate diversification has generally been a value‐reducing managerial strategy, why do firms remain diversified? One possibility, which the authors label the “agency cost” hypothesis, is that top executives without substantial equity stakes may have incentives to maintain a diversification strategy even if doing so reduces shareholder wealth. But, as top managers' ownership stakes increase, they bear a greater fraction of the costs associated with value‐reducing policies and are therefore less likely to take actions that reduce shareholder wealth. Also, to the extent that outside blockholders monitor managerial behavior, the agency cost hypothesis predicts that diversification will be less prevalent in firms with large outside blockholders. Consistent with this argument, the authors find that companies in which managers own a significant fraction of the firm's shares, and in which blockholders own a large fraction of shares, are significantly less likely to be diversified.If agency problems lead managers to maintain value‐reducing diversification strategies, what is it that leads some of these same firms to refocus? The agency cost hypothesis predicts that managers will reduce diversification only if pressured to do so by internal or external mechanisms that reduce agency problems. Consistent with this argument, the authors find that decreases in diversification appear to be precipitated by market disciplinary forces such as block purchases, acquisition attempts, and management turnover.