bluuebunny/crossref_metadata_2025 huggingface dataset:
Teachers' and students' verbal behaviours during cooperative and small‐group learning
Authors: Gillies Robyn M.
Published: May 2006

Background. Teachers play a critical role in promoting interactions between students and engaging them in the learning process. This study builds on a study by Hertz‐Lazarowitz and Shachar (1990) who found that during cooperative learning teachers' verbal behaviours were more helpful to and encouraging of their students' efforts while during whole‐class instruction, their verbal behaviours tended to be more authoritarian, rigid, and impersonal.

Aim. This study seeks to determine if teachers who implement cooperative learning engage in more facilitative learning interactions with their students than teachers who implement group work only. The study also seeks to determine if students in the cooperative groups model their teachers' behaviours and engage in more positive helping interactions with each other than their peers in the group work groups.

Samples. The study involved 26 teachers and 303 students in Grades 8 to10 from 4 large high schools in Brisbane, Australia.

Methods. All teachers agreed to establish cooperative, small‐group activities in their classrooms for a unit of work (4 to 6 weeks) once a term for 3 school terms. The teachers were audiotaped twice during these lessons and samples of the students' language, as they worked in their groups, were also collected at the same time.

Results. The results show that teachers who implement cooperative learning in their classrooms engage in more mediated‐learning interactions and make fewer disciplinary comments than teachers who implement group work only. Furthermore, the students model many of these interactions in their groups.

Conclusions. The study shows that when teachers implement cooperative learning, their verbal behaviour is affected by the organizational structure of the classroom.
Reading errors in first‐ and second‐grade readers of a shallow orthography: Evidence from Spanish
Authors: Goikoetxea Edurne
Published: May 2006

Background. Studies focusing on reading errors can help to understand how children learn to read and to structure key components of reading instruction. However, no prior studies have examined which letters might be a greater source of difficulty for beginning readers in Spanish.

Aims. First, to examine the pattern of reading errors in beginning readers in a shallow orthography like Spanish with a particular focus on both the context‐dependant (c, g, r) and the visual similar (b, d, g, p, q) consonants. (The dual‐route cascade model is used as a theoretical framework for predictions.) Second, to examine the effect of visual similarity on orientation reversals, using upper and lower case letters.

Sample. Ninety Spanish‐speaking children (45 in Grade 1 and 45 in Grade 2) participated in the study.

Method. Children were required to read aloud both words and non‐words. Seven categories of errors were examined. To clarify the influence of visual similarity of easily confused consonants (b, d), upper and lower case letters were used.

Results. We found that most reading errors (as a function of opportunity) were due to context‐dependant consonants (c, g, r), and a small proportion were due to the remaining consonants, or even the visually‐similar consonants. Further, visual similarity of reversible letters had a significant effect on orientation reversals. Finally, there was a significant influence of factors such as syllable frequency on the number of word errors.

Conclusions. The implications of these findings for early reading instruction and future research are discussed.
Book Reviews
Authors: Hartas Dimitra
Published: May 2006

Excluded from school – systemic practice for mental health and education professionals
Book Reviews
Authors: Strand Steve
Published: May 2006

Discovering statistics using SPSS (2nd edition)
Book Reviews
Authors: Carroll J. M.
Published: May 2006

Your undergraduate psychology project: A BPS guide
Book Reviews
Authors: Caryl P. G.
Published: May 2006

The mathematics of marriage: Dynamic nonlinear models Gottman

By J. M. Gottman, J. D. Murray, C. C. Swanson, R. Tyson & K. R. Swanson

Cambridge, MA: MIT Press, 2003. Cased £28.50. ISBN 0 262 072262
Book Reviews
Authors: Rutherford Andrew
Published: May 2006

Research design and statistical analysis

Myers Jerome L. and Well Arnold D. (2nd edn)

Mahwah, NJ: LEA 2003, £43.10. ISBN: 08058‐4037‐0
Book Reviews
Authors: Austin Elizabeth
Published: May 2006

Latent variable models: An introduction to factor, path and structural analysis

By Loehlin J. C.

Mahwah, NJ: Lawrence Erlbaum 2004, Paperback (ISBN 0805849106) $36, hardback (ISBN 0805849092) $79.95.
Book Reviews
Authors: Kornbrot Diana
Published: May 2006

Statistical power analysis (2nd edn)

By Murphy Kevin R. & Myors Brett

Mahwah, NJ: Lawrence Erlbaum 2004, Paperback, $22.50, ISBN 08058‐4526‐7, Cased $45, 08058‐4525‐9
Book Reviews
Authors: Austin Elizabeth
Published: May 2006

Handbook of parametric and nonparametric statistical procedures

By Sheskin D. J.

Boca Raton: Chapman & Hall 2004, Cased £85, ISBN 1584884401 2005
Parallel Changes in Global Protein Profiles During Long-Term Experimental Evolution in Escherichia coli
Authors: Pelosi Ludovic , Kühn Lauriane , Guetta Dorian , Garin Jérôme , Geiselmann Johannes , Lenski Richard E , Schneider Dominique
Published: May 2006

Twelve populations of Escherichia coli evolved in and adapted to a glucose-limited environment from a common ancestor. We used two-dimensional protein electrophoresis to compare two evolved clones, isolated from independently derived populations after 20,000 generations. Exceptional parallelism was detected. We compared the observed changes in protein expression profiles with previously characterized global transcription profiles of the same clones; this is the first time such a comparison has been made in an evolutionary context where these changes are often quite subtle. The two methodologies exhibited some remarkable similarities that highlighted two different levels of parallel regulatory changes that were beneficial during the evolution experiment. First, at the higher level, both methods revealed extensive parallel changes in the same global regulatory network, reflecting the involvement of beneficial mutations in genes that control the ppGpp regulon. Second, both methods detected expression changes of identical gene sets that reflected parallel changes at a lower level of gene regulation. The protein profiles led to the discovery of beneficial mutations affecting the malT gene, with strong genetic parallelism across independently evolved populations. Functional and evolutionary analyses of these mutations revealed parallel phenotypic decreases in the maltose regulon expression and a high level of polymorphism at this locus in the evolved populations.
Signatures of Demographic History and Natural Selection in the Human Major Histocompatibility Complex Loci
Authors: Meyer Diogo , Single Richard M , Mack Steven J , Erlich Henry A , Thomson Glenys
Published: May 2006

Many lines of evidence show that several HLA loci have experienced balancing selection. However, distinguishing among demographic and selective explanations for patterns of variation observed with HLA genes remains a challenge. In this study we address this issue using data from a diverse set of human populations at six classical HLA loci and, employing a comparative genomics approach, contrast results for HLA loci to those for non-HLA markers. Using a variety of analytic methods, we confirm and extend evidence for selection acting on several HLA loci. We find that allele frequency distributions for four of the six HLA loci deviate from neutral expectations and show that this is unlikely to be explained solely by demographic factors. Other features of HLA variation are explained in part by demographic history, including decreased heterozygosity and increased LD for populations at greater distances from Africa and a similar apportionment of genetic variation for HLA loci compared to putatively neutral non-HLA loci. On the basis of contrasts among different HLA loci and between HLA and non-HLA loci, we conclude that HLA loci bear detectable signatures of both natural selection and demographic history.
Functional Implication of an Arg307Gly Substitution in Corticosteroid-Binding Globulin, a Candidate Gene for a Quantitative Trait Locus Associated With Cortisol Variability and Obesity in Pig
Authors: Guyonnet-Dupérat Véronique , Geverink Nicoline , Plastow Graham S , Evans Gary , Ousova Olga , Croisetière Christian , Foury Aline , Richard Elodie , Mormède Pierre , Moisan Marie-Pierre
Published: May 2006

We previously reported that corticosteroid-binding globulin gene (Cbg) may be the causal gene of a quantitative trait locus associated with cortisol levels, fat deposition, and muscle content in a pig intercross. Sequence analysis of parental animals allowed us to identify four amino-acid substitutions. Here we have examined if any of these single amino acid substitutions could be responsible for the difference in CBG binding and affinity for cortisol between the parental breeds, using in vitro assays of Cbg variants after transfection of mammalian cells. Additionally, the Cbg coding region was analyzed in samples from a synthetic pig line to study association between polymorphism and CBG biochemical properties, carcass composition, and meat quality. Both in vitro transfection assays and the association studies suggest a role of the Arg307Gly mutation in increasing CBG capacity (by >70%) and decreasing CBG affinity for cortisol (by 30%). The Ile265Val substitution may also have an effect on decreasing CBG affinity for cortisol by 25%. The mutations Ser15Ile and Thr257Met do not seem to have an effect on CBG parameters. The Arg307Gly substitution was the only mutation associated with a parameter of meat quality and no mutation was linked to carcass composition.
Parent-of-Origin Effects on mRNA Expression in Drosophila melanogaster Not Caused by Genomic Imprinting
Authors: Wittkopp Patricia J , Haerum Belinda K , Clark Andrew G
Published: May 2006

Parent-of-origin effects create differences in gene expression among genetically identical individuals. Using measurements of allele-specific expression, we demonstrate that previously reported parent-of-origin effects on standing mRNA levels in Drosophila melanogaster are not attributable to genomic imprinting. Offspring from reciprocal crosses exhibit differences in total expression without differences in allelic expression, indicating that other types of maternal and/or paternal effects alter expression.
High-Resolution Mapping of Quantitative Trait Loci Affecting Increased Life Span in Drosophila melanogaster
Authors: Wilson Rhonda H , Morgan Theodore J , Mackay Trudy F C
Published: May 2006

Limited life span and senescence are near-universal characteristics of eukaryotic organisms, controlled by many interacting quantitative trait loci (QTL) with individually small effects, whose expression is sensitive to the environment. Analyses of mutations in model organisms have shown that genes affecting stress resistance and metabolism affect life span across diverse taxa. However, there is considerable segregating variation for life span in nature, and relatively little is known about the genetic basis of this variation. Replicated lines of Drosophila that have evolved increased longevity as a correlated response to selection for postponed senescence are valuable resources for identifying QTL affecting naturally occurring variation in life span. Here, we used deficiency complementation mapping to identify at least 11 QTL on chromosome 3 that affect variation in life span between five old (O) lines selected for postponed senescence and their five base (B) population control lines. Most QTL were sex specific, and all but one affected multiple O lines. The latter observation is consistent with alleles at intermediate frequency in the base population contributing to the response to selection for postponed senescence. The QTL were mapped with high resolution and contained from 12 to 170 positional candidate genes.
Analysis of the Proteins Involved in thein VivoRepair of Base–Base Mismatches and Four-Base Loops Formed During Meiotic Recombination in the YeastSaccharomyces cerevisiae
Authors: Stone Jana E , Petes Thomas D
Published: May 2006

DNA mismatches are generated when heteroduplexes formed during recombination involve DNA strands that are not completely complementary. We used tetrad analysis in Saccharomyces cerevisiae to examine the meiotic repair of a base–base mismatch and a four-base loop in a wild-type strain and in strains with mutations in genes implicated in DNA mismatch repair. Efficient repair of the base–base mismatch required Msh2p, Msh6p, Mlh1p, and Pms1p, but not Msh3p, Msh4p, Msh5p, Mlh2p, Mlh3p, Exo1p, Rad1p, Rad27p, or the DNA proofreading exonuclease of DNA polymerase δ. Efficient repair of the four-base loop required Msh2p, Msh3p, Mlh1p, and Pms1p, but not Msh4p, Msh5p, Msh6p, Mlh2p, Mlh3p, Exo1p, Rad1p, Rad27p, or the proofreading exonuclease of DNA polymerase δ. We find evidence that a novel Mlh1p-independent complex competes with an Mlhp-dependent complex for the repair of a four-base loop; repair of the four-base loop was affected by loss of the Mlh3p, and the repair defect of the mlh1 and pms1 strains was significantly smaller than that observed in the msh2 strain. We also found that the frequency and position of local double-strand DNA breaks affect the ratio of mismatch repair events that lead to gene conversion vs. restoration of Mendelian segregation.
A Clarification of the Hardy–Weinberg Law
Authors: Stark Alan E
Published: May 2006

C. C. Li showed that Hardy–Weinberg proportions (HWP) can be maintained in a large population by nonrandom mating as well as random mating. In particular he gave the mating matrix for the symmetric case in the most general form possible. Thus Li showed that, once HWP are attained, the same proportions can be maintained by what he called pseudorandom mating. This article shows that, starting from any genotypic distribution at a single locus with two alleles, the same in each sex, HWP can be reached in one round of nonrandom mating with no change in allele frequency. In the model that demonstrates this fact, random mating is represented by a single point in a continuum of nonrandom possibilities.
A Novel Approach for Characterizing Expression Levels of Genes Duplicated by Polyploidy
Authors: Udall Joshua A , Swanson Jordan M , Nettleton Dan , Percifield Ryan J , Wendel Jonathan F
Published: May 2006

Studying gene expression in polyploids is complicated by genomewide gene duplication and the problem of distinguishing transcript pools derived from each of the two homeologous genomes such as the A- and D-genomes of allotetraploid Gossypium. Short oligonucleotide probes designed to specifically target several hundred homeologous gene pairs of Gossypium were printed on custom NimbleGen microarrays. These results demonstrate that relative expression levels of homeologous genes may be measured by microarrays and that deviation from equal expression levels of homeologous loci may be common in the allotetraploid nucleus of Gossypium.
The Hill–Robertson Effect and the Evolution of Recombination
Authors: Roze Denis , Barton Nick H
Published: May 2006

In finite populations, genetic drift generates interference between selected loci, causing advantageous alleles to be found more often on different chromosomes than on the same chromosome, which reduces the rate of adaptation. This “Hill–Robertson effect” generates indirect selection to increase recombination rates. We present a new method to quantify the strength of this selection. Our model represents a new beneficial allele (A) entering a population as a single copy, while another beneficial allele (B) is sweeping at another locus. A third locus affects the recombination rate between selected loci. Using a branching process model, we calculate the probability distribution of the number of copies of A on the different genetic backgrounds, after it is established but while it is still rare. Then, we use a deterministic model to express the change in frequency of the recombination modifier, due to hitchhiking, as A goes to fixation. We show that this method can give good estimates of selection for recombination. Moreover, it shows that recombination is selected through two different effects: it increases the fixation probability of new alleles, and it accelerates selective sweeps. The relative importance of these two effects depends on the relative times of occurrence of the beneficial alleles.
Transcriptionally Silenced Transgenes in Maize Are Activated by Three Mutations Defective in Paramutation
Authors: McGinnis Karen M , Springer Catherine , Lin Yan , Carey Charles C , Chandler Vicki
Published: May 2006

Plants with mutations in one of three maize genes, mop1, rmr1, and rmr2, are defective in paramutation, an allele-specific interaction that leads to meiotically heritable chromatin changes. Experiments reported here demonstrate that these genes are required to maintain the transcriptional silencing of two different transgenes, suggesting that paramutation and transcriptional silencing of transgenes share mechanisms. We hypothesize that the transgenes are silenced through an RNA-directed chromatin mechanism, because mop1 encodes an RNA-dependent RNA polymerase. In all the mutants, DNA methylation was reduced in the active transgenes relative to the silent transgenes at all of the CNG sites monitored within the transgene promoter. However, asymmetrical methylation persisted at one site within the reactivated transgene in the rmr1-1 mutant. With that one mutant, rmr1-1, the transgene was efficiently resilenced upon outcrossing to reintroduce the wild-type protein. In contrast, with the mop1-1 and rmr2-1 mutants, the transgene remained active in a subset of progeny even after the wild-type proteins were reintroduced by outcrossing. Interestingly, this immunity to silencing increased as the generations progressed, consistent with a heritable chromatin state being formed at the transgene in plants carrying the mop1-1 and rmr2-1 mutations that becomes more resistant to silencing in subsequent generations.
Wild-Derived XY Sex-Reversal Mutants in the Medaka,Oryzias latipes
Authors: Otake Hiroyuki , Shinomiya Ai , Matsuda Masaru , Hamaguchi Satoshi , Sakaizumi Mitsuru
Published: May 2006

The medaka, Oryzias latipes, has an XX/XY sex-determination mechanism. A Y-linked DM domain gene, DMY, has been isolated by positional cloning as a sex-determining gene in this species. Previously, we found 23 XY sex-reversed females from 11 localities by examining the genotypic sex of wild-caught medaka. Genetic analyses revealed that all these females had Y-linked gene mutations. Here, we aimed to clarify the cause of this sex reversal. To achieve this, we screened for mutations in the amino acid coding sequence of DMY and examined DMY expression at 0 days after hatching (dah) using densitometric semiquantitative RT–PCR. We found that the mutants could be classified into two groups. One contained mutations in the amino acid coding sequence of DMY, while the other had reduced DMY expression at 0 dah although the DMY coding sequence was normal. For the latter, histological analyses indicated that YwOurYwOur (YwOur, Y chromosome derived from an Oura XY female) individuals with the lowest DMY expression among the tested mutants were expected to develop into females at 0 dah. These results suggest that early testis development requires DMY expression above a threshold level. Mutants with reduced DMY expression may prove valuable for identifying DMY regulatory elements.
Loss-Of-Function Alleles of the JIL-1 Kinase Are Strong Suppressors of Position Effect Variegation of the wm4 Allele in Drosophila
Authors: Lerach Stephanie , Zhang Weiguo , Bao Xiaomin , Deng Huai , Girton Jack , Johansen Jørgen , Johansen Kristen M
Published: May 2006

In this article we show that hypomorphic loss-of-function alleles of the JIL-1 histone H3S10 kinase are strong suppressors of position effect variegation (PEV) of the wm4 allele and that lack of JIL-1 activity can counteract the effect of the dominant enhancer E(var)2-1 on PEV.
Toward a Molecular Understanding of Pleiotropy
Authors: He Xionglei , Zhang Jianzhi
Published: May 2006

Pleiotropy refers to the observation of a single gene influencing multiple phenotypic traits. Although pleiotropy is a common phenomenon with broad implications, its molecular basis is unclear. Using functional genomic data of the yeast Saccharomyces cerevisiae, here we show that, compared with genes of low pleiotropy, highly pleiotropic genes participate in more biological processes through distribution of the protein products in more cellular components and involvement in more protein–protein interactions. However, the two groups of genes do not differ in the number of molecular functions or the number of protein domains per gene. Thus, pleiotropy is generally caused by a single molecular function involved in multiple biological processes. We also provide genomewide evidence that the evolutionary conservation of genes and gene sequences positively correlates with the level of gene pleiotropy.
Exonuclease Requirements for Recombination of λ-Phage inrecDMutants ofEscherichia coli
Authors: Ðermić Damir , Zahradka Davor , Petranović Mirjana
Published: May 2006

Recombination of λ red gam phage in recD mutants is unaffected by inactivation of RecJ exonuclease. Since nucleases play redundant roles in E. coli, we inactivated several exonucleases in a recD mutant and discovered that 5′–3′ exonuclease activity of RecJ and exonuclease VII is essential for λ-recombination, whereas exonucleases of 3′–5′ polarity are dispensable. The implications of the presented data on current models for recombination initiation in E. coli are discussed.
Cis-transcriptional Variation in Maize Inbred Lines B73 and Mo17 Leads to Additive Expression Patterns in the F1 Hybrid
Authors: Stupar Robert M , Springer Nathan M
Published: May 2006

Microarray analysis of gene expression patterns in immature ear, seedling, and embryo tissues from the maize inbred lines B73 and Mo17 identified numerous genes with variable expression. Some genes had detectable expression in only one of the two inbreds; most of these genes were detected in the genomic DNA of both inbreds, indicating that the expression differences are likely caused by differential regulation rather than by differences in gene content. Gene expression was also monitored in the reciprocal F1 hybrids B73 × Mo17 and Mo17 × B73. The reciprocal F1 hybrid lines did not display parental effects on gene expression levels. Approximately 80% of the differentially expressed genes displayed additive expression patterns in the hybrids relative to the inbred parents. The ∼20% of genes that display nonadditive expression patterns tend to be expressed at levels within the parental range, with minimal evidence for novel expression levels greater than the high parent or less than the low parent. Analysis of allele-specific expression patterns in the hybrid suggested that intraspecific variation in gene expression levels is largely attributable to cis-regulatory variation in maize. Collectively, our data suggest that allelic cis-regulatory variation between B73 and Mo17 dictates maintenance of inbred allelic expression levels in the F1 hybrid, resulting in additive expression patterns.
Clinical Manifestations and Risk Factors of Children Receiving Triple Ventilating Tube Insertions for Treatment of Recurrent Otitis Media With Effusion
Authors: Ahn Joong Ho , Yoon Tae Hyun , Pae Ki Hoon , Kim Tae Su , Chung Jong Woo , Lee Kwang-Sun
Published: May 2006

OBJECTIVE. Our goal was to determine risk factors for children receiving additional ventilating tube insertions after initial tube insertion and to determine the changes of clinical manifestations in children who have undergone 3 ventilating tube insertion procedures.

STUDY DESIGN. We retrospectively analyzed medical and operation records of 423 young patients who had ventilating tube insertion because of chronic otitis media with effusion from January 1993 to December 1998. The single-operation group included patients who had 1 ventilating tube insertion only, and the triple-operation group included patients who received ventilating tube insertion 3 times because of recurring chronic otitis media with effusion.

RESULTS. At the first operation, there were significant differences between the single- and triple-operation groups in mean age, the proportion who received a concurrent adenoidectomy, the mean indwelling period of the first ventilating tube, the proportion who developed postoperative otorrhea within 1 month, and the proportion who had early extrusion of the ventilating tube within 3 months of surgery. In the triple-operation group, the accumulated number of adenoidectomies, the indwelling period of the ventilating tube, and the time interval before subsequent ventilating tube insertion after ventilating tube extrusion significantly increased as ventilating tube insertion procedures were performed repeatedly. Although there was no difference when compared with the single-operation group, the proportion of glue-like effusion significantly decreased as ventilating tube insertion procedures were performed repeatedly. There were no significant differences between the single- and triple-operation groups in male/female ratio, site of ventilating tube insertion, and the proportion of patients with glue-like effusion at the first ventilating tube insertion.

CONCLUSIONS. The probability of receiving additional ventilating tube insertion because of recurrent otitis media with effusion significantly increased in younger patients at the time of first ventilating tube insertion. The concurrent adenoidectomy, duration of the ventilating tube, postoperative otorrhea within 1 month, and early extrusion of the ventilating tube also influenced the probability of additional ventilating tube insertion.
Cadmium content of Finnish linseed and estimated consumer intake
Authors: KYMÄLÄINEN H-R. , SJÖBERG A-M.
Published: May 2006

The aim of this study was to screen the cadmium (Cd) contents of seed and seed crush of Finnish linseed and to evaluate the acceptable daily dose. The Cd content of Finnish linseed is of interest, since some properties of linseed as the content of fatty acids are different in northern growth locations compared with other growing areas. Seed samples (N = 85) were collected from the experimental farm of Helsinki University and from commercial fields in different locations in southern Finland and Ostrobothnia. In addition, 15 samples of linseed crush were examined. The cadmium contents of the linseed samples, determined with atomic absorption spectroscopy, varied between 0.27 and 1.3 mg kg-1 (dry weight) (mean 0.61 mg kg-1). The Cd contents of the crush samples were between 0.47 and 1.5 mg kg-1 (mean 0.85 mg kg-1). There were differences between the Cd contents of the three examined varieties and years at the experimental farm. Increase in nitrogen fertilization somewhat increased the Cd uptake of linseed. The permitted intake of linseed depends on body weight and on the Cd content of the product and is in most cases higher than the dietary recommendation (2430 g daily dose of linseed).;
Sowing time affects the abundance of pests and weeds in winter rye
Authors: HUUSELA-VEISTOLA E. , JALLI H. , SALONEN J.
Published: May 2006

Selection of an appropriate sowing time for some winter rye (Secale cereale) cultivars could reduce the need for crop protection measures. In this study the occurrence and status of pests and weeds in relation to sowing time and growth habit of winter rye was studied in southern Finland. This was done using three sowing times and four rye varieties in field trials conducted at three locations in 19992001. The early sown rye was severely affected by pests (Oscinella frit, Mayetiola destructor) and weeds, whereas postponing sowing for two weeks after the recommended sowing time in late August resulted in considerably less damage and the optimal establishment of crop stands. The German hybrid varieties Picasso and Esprit produced more tillers m-2 in autumn than the Finnish varieties Anna and Bor 7068. However, the number of pests and weeds did not differ among rye varieties. Late sowing of rye should be considered to minimize the need for plant protection. If rye is sown at the recommended time it may still require insecticide treatments promptly in the autumn whereas herbicide treatment need not be determined until spring, after recording the winter mortality of weeds.;
Annual and seasonal changes in mineral contents (Ca, Mg, P, K and Na) of grazed clover-grass mixtures in organic farming
Authors: KUUSELA E.
Published: May 2006

A grazed field experiment was established in 1995 to evaluate alsike clover (Trifoliun hybridum L.), red clover (Trifolium pratense L.) and white clover (Trifolium repens L.) in clover-grass mixtures under organic farming practices. In this study the effect of seed mixture (alsike clover, red clover, white clover, white and alsike clover or grass mixture), year (1997, 1998) and grazing period (5 per grazing season) on the herbage calcium (Ca), magnesium (Mg), potassium (K) phosphorous (P) and sodium (Na) contents was assessed and the relationships between botanical proportions and herbage mineral contents were studied. Herbage Ca and Na contents varied between the seed mixtures, Ca, Mg, P and Na contents between the years and all measured minerals, except Na, between the grazing periods. The white clover mixture resulted in higher Ca and Na contents. The contents of Ca and Mg were positively related with the proportions of clovers and weeds and were higher in 1997. The contents of P and K were higher in the rainy summer of 1998. The seed mixtures resulted in similar mean K/(Ca + Mg) equivalent ratios, but the Ca/P ratio was higher for the white clover mixture. Mineral rations varied between and within grazing seasons. Under organic practices the supply of minerals in the pasture herbage varied temporally and according to the botanical contents and was unable to meet fully the requirements of dairy cows. Additional mineral feeding is recommended for organic farming systems to balance the dietary mineral contents for grazing cows.;
Insect pests and their natural enemies on spring oilseed rape in Estonia : impact of cropping systems
Authors: VEROMANN E. , TARANG T. , KEVVÄI R.
Published: May 2006

To investigate the impact of different cropping systems, the pests, their hymenopteran parasitoids and predatory ground beetles present in two spring rape crops in Estonia, in 2003, were compared. One crop was grown under a standard (STN) cropping system and the other under a minimised (MIN) system. The STN system plants had more flowers than those in the MIN system, and these attracted significantly more Meligethes aeneus, the only abundant and real pest in Estonia. Meligethes aeneus had two population peaks: the first during opening of the first flowers and the second, the new generation, during ripening of the pods. The number of new generation M. aeneus was almost four times greater in the STN than in the MIN crop. More carabids were caught in the MIN than in STN crop. The maximum abundance of carabids occurred two weeks before that of the new generation of M. aeneus, at the time when M. aeneus larvae were dropping to the soil for pupation and hence were vulnerable to predation by carabids.
Prochloraz tolerance of Pyrenophora teres population in Finland
Authors: SERENIUS M. , MANNINEN O.
Published: May 2006

Barley leaves infected with Pyrenophora teres Drechs. f. teres were collected from farmers fields and an experimental field for evaluation of efficacy of fungicides at MTT Agrifood Research Finland (MTT), in 2003. The aim was to test the efficacy of prochloraz to inhibit in vitro growth of P. teres. Potato dextrose agar (PDA) dishes amended with 0.1 and 1.0 ìg ml-1 prochloraz were used for testing 364 isolates of P. teres based on prelimenary experiment. Isolates from MTTs experimental field were growing slower on fungicide- amended media than isolates from farmers fields. The overall mean inhibition of radial growth was 63 and 86% on media amended with 0.1 and on 1.0 ìg ml-1 prochloraz, respectively. Isolates of different origin differed significantly on growth on fungicide-amended media. The isolates capable of growing on increased concentrations of prochloraz were most commonly isolated from fields, where prochloraz was sprayed during the growing season. Within MTTs experimental field no effect of fungicide application during the growing season was observed on growth of isolates in vitro. Data from this survey was insufficient for making further conclusions regarding the effect of agricultural practices on selection of fungicide tolerant P. teres isolates. Fungicides with different types of mode of action are recommended for use together with prochloraz against the net blotch pathogen in Finland. These results are preliminary.;
Reducing Asthma Triggers in Schools: Recommendations for Effective Policies, Regulations, and Legislation
Authors: Parker Joan N. , Dunn Mary Lee
Published: May 2006

While 31 million Americans have been diagnosed with asthma, children are most severely affected. Asthma also is common among teachers, indicating that the school building environment may be associated with asthma prevalence among occupants. Children are sensitive to environmental pollutants, which are more concentrated in indoor air environments. Schools are a significant source of indoor air pollutants. Yet little research has addressed the causal relationship between asthma and specific levels of indoor pollutants. Indoor air quality is seldom controlled in schools in a way that minimizes such exposures. While few laws limit indoor air pollutants in schools, some laws outline or mandate practices that can control exposures. This report presents recommendations for laws and regulations that control and, ideally, prevent indoor air quality problems and aims to reduce or mitigate such disease.
From Sara to Homeland Security: The Niehs Worker Education and Training Program Confronts Challenges of Environmental Cleanup
Authors: Slatin Craig , Dunn Mary Lee
Published: May 2006

Section 126(g) of the Superfund Amendments and Reauthorization Act of 1986 mandated the National Institute of Environmental Health Sciences to establish a grant program for the training and education of hazardous waste operations and emergency response workers. This program, originally established as the Superfund Worker Training Program, has evolved into the Worker Education and Training Program (WETP) and is currently in its nineteenth year of successful operation. Beginning with eleven awardees in 1987, it currently supports eighteen awardees that include more than one hundred organizations nationally. The NIEHS WETP built upon the lessons learned from earlier worker health education and training programs to establish a national worker health education intervention that has demonstrated the capacity of and potential for public health excellence. The principles and practices established as the program's foundation in its first five years are detailed, providing a basis for understanding how the program was able to take an active supporting role in response to the national disasters on September 11, 2001.
Immigrant Workers are Our Allies, Not Our Enemies
Authors: Brown Garrett
Published: May 2006

The cold, hard reality of the global “savage capitalism” will be the greatest recruiter for unions offering real protections for workers. Health and safety issues have long been recognized as key to organizing workers. There is a positive “union effect” on workplace health and safety when informed and active workers are part of a member-controlled union on site. Solidarity among all working people in the global economy is essential. It will be a challenge in the U.S. because of recent efforts to scapegoat immigrant workers. But it is crucial that we overcome that corporation-absolving approach. Our future depends on us seeing Mexican or Chinese workers—in the U.S. or in their own countries—as “fellow workers” with the same problems and goals as us.
Guilty! Successful Homicide Prosecution against Company That Killed Two Workers in Arizona
Authors: Barab Jordan , Dunn Mary Lee
Published: May 2006

Why should an employer who sends a worker to his death in an unmonitored confined space or an unprotected 12-foot deep trench not be prosecuted under a felony as opposed to the Occupational Safety and Health Act, where the maximum penalty for willfully killing a worker is a misdemeanor with a maximum of six months in jail? They should be so charged. The author deplores merely waiting for Congress to increase OSHA penalties.
Magnetic field generation from cosmological perturbations
Authors: Takahashi K. , Ichiki K. , Ohno H. , Hanayama H. , Sugiyama N.
Published: May 2006

We discuss generation of magnetic field from cosmological perturbations. We consider the evolution of three component plasma (electron, proton and photon) evaluating the collision term between elecrons and photons up to the second order. The collision term is shown to induce electric current, which then generate magnetic field. There are three contributions, two of which can be evaluated from the first‐order quantities, while the other one is fluid vorticity which is purely second order. We compute numerically the magnitudes of the former contributions and shows that the amplitude of the produced magnetic field is about ∼ 10–19 G at 10 kpc comoving scale at present. Compared to astrophysical and inflationary mechanisms for seed‐.eld generation, our study suffers from much less ambiguities concerning unknown physics and/or processes. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Effects of cosmological magnetic helicity on the CMB
Authors: Kahniashvili T.
Published: May 2006

I present a short review of primordial magnetic helicity effects on Cosmic Microwave Background (CMB) temperature and polarization anisotropies. These effects allow us to test for cosmological magnetic helicity; however, very accurate CMB fluctuation data are required. This scheme for magnetic helicity detection is valid only for a cosmological magnetic field with a present amplitude larger than 10–9–10–10 Gauss. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Nonlinear amplification of the magnetized pancakes
Authors: Siemieniec‐Oziȩbło G. , Woszczyna A.
Published: May 2006

Nonlinear growth of one‐dimensional density structures with a frozen‐in magnetic field is investigated in Newtonian cosmology. A mechanism of magnetic field amplification is discussed. We discuss the relation between the initial conditions for the velocity field and the basic time‐scales determining the growth of the magnetized structure. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Formation of large‐scale magnetic‐towers in quasars
Authors: Kato Y.
Published: May 2006

The evolution of accretion disks and the formation of jets around super‐massive black holes are studied by 3‐D magnetohydrodynamic simulations. The previous studies of astrophysical jets have been concentrated on the effects of large‐scale magnetic fields permeating accretion disks. However, the existence of such global magnetic fields is not evident in astrophysical objects, and their origin is not well understood. Instead, we concentrate on the effect of the magnetic fields amplified as a result of the magneto‐rotational instability in the differentially rotating disk. In our simulations, we found the emergence of accumulated toroidal magnetic fields from the inner region of the disk (a so‐called magnetic‐tower) and also the formation of jets accelerated by the magnetic pressure of the magnetic‐tower. The magnetic energy, ejected by the magnetic‐tower jet during a lifetime of an active galactic nuclei (AGNs), is about 1046 erg. Our results indicate that the magnetic‐tower jet can be one of the most powerful process for the formation and the evolution of the large‐scale structured magnetic .elds in the cluster of galaxies. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Dynamos from large‐scale flows versus α ‐effect
Authors: Arlt R.
Published: May 2006

The observation of certain longitudes on stars which show persistent activity requires non‐axisymmetric dynamo solutions which coexist with the typical axisymmetric, oscillatory dynamo solutions known from mean‐field α ‐dynamos. This study is an attempt of finding non‐axisymmetric solutions arising from large‐scale flows with meridional circulation and a differential rotation imitating the ones in stars. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Magnetic fields in the Southern Galactic Plane Survey
Authors: Haverkorn M. , Gaensler B. M. , Brown J.‐A. C. , McClure‐Griffiths N. M. , Dickey J. M. , Green A. J.
Published: May 2006

The Southern Galactic Plane Survey (SGPS) is a 1.4 GHz radio polarization and H I survey in a large part of the inner Galactic plane at a resolution of about an arcmin. Depolarization and Faraday rotation of polarized radiation from diffuse Galactic synchrotron emission, pulsars, and extragalactic sources can be used to infer information about the strength and structure of the Galactic magnetic field. Here, we discuss early results of the polarization data from the SGPS. We show from statistical analysis of rotation measures of polarized extragalactic sources that fluctuations in the magnetoionized medium of the spiral arms are probably mainly caused by H II regions, while the rotation measure fluctuations in the interarm regions may be connected to the interstellar turbulent cascade. Furthermore, the variations of rotation measure with Galactic longitude enable modeling of the large‐scale component of the Galactic magnetic field, including determination of the number and location of magnetic field reversals. Finally, the SGPS is an excellent way to study subparsec‐scale structure in the ionized interstellar medium by way of depolarization studies in H II regions. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
A statistical analysis of a Galactic all sky survey at 1.4 GHz
Authors: Burigana C. , La Porta L. , Reich P. , Reich W.
Published: May 2006

Radio surveys at frequencies of ∼ 1 GHz allow to map the synchrotron emission (SE) in a frequency range where (except for very low Galactic latitudes or towards localized regions) it dominates over the other radio components. New all sky total intensity and polarization data at 1.4 GHz have been recently collected.We focus on the Galactic radio emission correlation properties described in terms of angular power spectrum (APS).We present for the first time the APS, in both total intensity and polarization modes, for some representative Galactic cuts and suitable APS power law (PL) parametrizations. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
The origin of magnetic fields in galaxies: Observational tests with the Square Kilometre Array
Authors: Beck R.
Published: May 2006

The all‐sky survey of Faraday rotation , a Key Science Project of the planned Square Kilometre Array, will accumulate tens of millions of rotation measure measurements toward background radio sources and will provide a unique database for characterizing the overall magnetic geometry of magnetic fields in galaxies and in the intergalactic medium. Deep imaging of the polarized synchrotron emission from a large number of nearby galaxies, combined with Faraday rotation data, will allow us to test primordial, gas flow, and dynamo models for field origin and amplification. The SKA will find the first magnetic fields in young galaxies and determine the timescale for building up small‐scale turbulent and large‐scale coherent fields. The spectrum of dynamo modes, if existing, will be resolved. The present‐day coherent field may keep memory of the direction of the seed field which can be used for mapping the structure of the seed field before galaxy formation. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Extragalactic radio sources, IGM magnetic fields, and AGN‐based energy flows
Authors: Kronberg P. P.
Published: May 2006

I review the interconnections between extragalactic radio sources and extragalactic magnetic fields in large‐scale structure. I focus on energy flows and magnetic fields arising from AGN‐powered radio sources. A new combined Faraday rotation (RM) and galaxy count analysis is described which provides the first Faraday RM test for magnetic field strengths in regions of local cosmological large‐scale structure. I also describe both recent and new results that probe intergalactic magnetic fields via faint synchrotron radiation at the lowest detectable levels. Evidence for the cosmologically early generation of significant magnetic fields in galaxy systems is briefly reviewed, including initial results of a new global RM probe out to redshifts greater than 3. In the course of reviewing these new results, I comment on some desirable specifications of next‐generation instruments. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Observations of magnetic fields in regular and irregular clusters
Authors: Govoni F.
Published: May 2006

The existence of magnetic fields associated with the intracluster medium in clusters of galaxies is now well established through different methods of analysis. The most detailed evidence for the presence of cluster magnetic fields comes from radio observations. Magnetic fields can be investigated through the synchrotron emission of cluster‐wide diffuse sources and from studies of the rotation measure of polarized radio galaxies. I will review efforts to measure magnetic field strengths and power spectra and the main issues that have led to our knowledge on magnetic fields in regular and irregular clusters of galaxies. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Radio emission of galaxy clusters
Authors: Golombek I. , Bartelmann M. , Enßlin T. , Jubelgas M. , Pfrommer C. , Springel V.
Published: May 2006

We use a simplified numerical model for the relativistic electron population originating from hadronic proton decays inside a galaxy cluster to calculate its characteristic radio synchrotron emission under the influence of strong accretion and merger shocks. Earlier investigations showed that during structure formation the ICM magnetic field can be substantially magnified.We therefore expect the cluster dynamics to manifest itself in the observable synchrotron emission. Comparison to observations will help us gain better insight into the physics of cluster formation. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Simulations of magnetic fields in the cosmos
Authors: Brüggen M. , Hoeft M.
Published: May 2006

The origin of large‐scale magnetic fields in clusters of galaxies remains controversial. The intergalactic magnetic field within filaments should be less polluted by magnetised outflows from active galaxies than magnetic fields in clusters. Therefore, filaments may be a better laboratory to study magnetic field amplification by structure formation than galaxy clusters, which typically host many more active galaxies. We present highly resolved cosmological adaptive mesh refinement simulations of magnetic fields in the cosmos and make predictions about the evolution and structure of magnetic fields in filaments. Comparing our results to observational evidence of magnetic fields in filaments suggests that amplification of seed fields by gravitational collapse is not sufficient to produce intergalactic medium fields. Finally, implications for cosmic ray transport and the impact of magnetic fields on delayed photons from gamma‐ray bursts are discussed. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)