Correlation of the highest-energy cosmic rays with the positions of nearby active galactic nuclei

Data collected by the Pierre Auger Observatory provide evidence for anisotropy in the arrival directions of the cosmic rays with the highest-energies, which are correlated with the positions of relatively nearby active galactic nuclei (AGN) [Pierre Auger Collaboration, Science 318 (2007) 938]. The correlation has maximum significance for cosmic rays with energy greater than similar to 6 x 10(19) eV and AGN at a distance less than similar to 75 Mpc. We have confirmed the anisotropy at a confidence level of more than 99% through a test with parameters specified a priori, using an independent data set. The observed correlation is compatible with the hypothesis that cosmic rays with the highest-energies originate from extra-galactic sources close enough so that their flux is not significantly attenuated by interaction with the cosmic background radiation (the Greisen-Zatsepin-Kuz`min effect). The angular scale of the correlation observed is a few degrees, which suggests a predominantly light composition unless the magnetic fields are very weak outside the thin disk of our galaxy. Our present data do not identify AGN as the sources of cosmic rays unambiguously, and other candidate sources which are distributed as nearby AGN are not ruled out. We discuss the prospect of unequivocal identification of individual sources of the highest-energy cosmic rays within a few years of continued operation of the Pierre Auger Observatory. (C) 2008 Elsevier B.V. All rights reserved.

Molecular analysis of maltotriose active transport and fermentation by Saccharomyces cerevisiae reveals a determinant role for the AGT1 permease

Incomplete and/or sluggish maltotriose fermentation causes both quality and economic problems in the ale-brewing industry. Although it has been proposed previously that the sugar uptake must be responsible for these undesirable phenotypes, there have been conflicting reports on whether all the known alpha-glucoside transporters in Saccharomyces cerevisiae (MALx1, AGT1, and MPH2 and MPH3 transporters) allow efficient maltotriose utilization by yeast cells. We characterized the kinetics of yeast cell growth, sugar consumption, and ethanol production during maltose or maltotriose utilization by several S. cerevisiae yeast strains (both MAL constitutive and AM inducible) and by their isogenic counterparts with specific deletions of the AGT1 gene. Our results clearly showed that yeast strains carrying functional permeases encoded by the MAL21, MAL31, and/or MAL41 gene in their plasma membranes were unable to utilize maltotriose. While both high-and low-affinity transport activities were responsible for maltose uptake from the medium, in the case of maltotriose, the only low-affinity (K-m, 36 +/- 2 mM) transport activity was mediated by the AGT1 permease. In conclusion, the AGT1 transporter is required for efficient maltotriose fermentation by S. cerevisiae yeasts, highlighting the importance of this permease for breeding and/or selection programs aimed at improving sluggish maltotriose fermentations.

Micellar properties of surface active ionic liquids: A comparison of 1-hexadecyl-3-methylimidazolium chloride with structurally related cationic surfactants

Ionic liquids, ILs, carrying long-chain alkyl groups are surface active, SAIIs. We investigated the micellar properties of the SAIL 1-hexadecyl-3-methylimidazolium chloride, C(16)MeImCl, and compared the data with 1-hexadecylpyridinium chloride, C(16)PYCl, and benzyl (3-hexadecanoylaminoethyl)dimethylammonium chloride, C(15)AEtBzMe(2)Cl. The properties compared include critical micelle concentration, cmc; thermodynamic parameters of micellization; empirical polarity and water concentrations in the interfacial regions. In the temperature range from 15 to 75 degrees C, the order of cmc in H(2)O and in D(2)O is C(16)PYCl > C(16)MeImCl > C(15)AEtBzMe(2)Cl. The enthalpies of micellization, Delta H(mic)(degrees), were calculated indirectly from by use of the van`t Hoff treatment; directly by isothermal titration calorimetry, ITC. Calculation of the degree of counter-ion dissociation, alpha(mic), from conductivity measurements, by use of Evans equation requires knowledge of the aggregation numbers, N(agg), at different temperatures. We have introduced a reliable method for carrying out this calculation, based on the volume and length of the monomer, and the dependence of N(agg) on temperature. The N(agg) calculated for C(16)PyCl and C(16)MeImCl were corroborated by light scattering measurements. Conductivity- and ITC-based Delta H(mic)(degrees) do not agree; reasons for this discrepancy are discussed. Micelle formation is entropy driven: at all studied temperatures for C(16)MeImCl; only up to 65 degrees C for C(16)PyCl; and up to 55 degrees C for C(15)AEtBzMe(2)Cl. All these data can be rationalized by considering hydrogen-bonding between the head-ions of the monomers in the micellar aggregate. The empirical polarities and concentrations of interfacial water were found to be independent of the nature of the head-group. (C) 2010 Elsevier Inc. All rights reserved.

Aspects of comparative active citizenship

This paper reports results from surveys of community organisation members, workers and volunteers designed to measure aspects of active citizenship in four locations: Ballarat (Australia); Norwich and Downham Market (England), and Mitischi (Russia). These data are drawn from an ongoing comparative study that will include six countries in the final analysis. The aggregated data considered here lend support to propositions that tolerance is positively associated with both civic participation and trust but do not show evidence for association between civic participation and trust. However, the existence of considerable locality level variation underlines the importance of taking context into account when assessing the role and nature of civic participation. Across the four locations, two broad patterns of (relative) active citizenship are described by means of a typology of active citizens. Predictors of tolerance and civic participation are identified through standard multiple regressions. It is concluded that future research needs to uncover the explanatory factors that lie behind these representations and which could further specify not just the similarities but also the differences between the locations.

Purification and membrane reconstitution of catalytically active Menkes copper-transporting P-type ATPase (MNK; ATP7A)

The MNK (Menkes disease protein; ATP7A) is a major copper- transporting P-type ATPase involved in the delivery of copper to cuproenzymes in the secretory pathway and the efflux of excess copper from extrahepatic tissues. Mutations in the MNK (ATP7A) gene result in Menkes disease, a fatal neurodegenerative copper deficiency disorder. Currently, detailed biochemical and biophysical analyses of MNK to better understand its mechanisms of copper transport are not possible due to the lack of purified MNK in an active form. To address this issue, we expressed human MNK with an N-terminal Glu-Glu tag in Sf9 [Spodoptera frugiperda (fall armyworm) 9] insect cells and purified it by antibody affinity chromatography followed by size-exclusion chromatography in the presence of the non-ionic detergent DDM (n-dodecyl b-D-maltopyranoside). Formation of the classical vanadate-sensitive phosphoenzyme by purified MNK was activated by Cu(I) [EC50=0.7 µM; h (Hill coefficient) was 4.6]. Furthermore, we report the first measurement of Cu(I)-dependent ATPase activity of MNK (K0.5=0.6 µM; h=5.0). The purified MNK demonstrated active ATP-dependent vectorial 64Cu transport when reconstituted into soya-bean asolectin liposomes. Together, these data demonstrated that Cu(I) interacts with MNK in a co-operative manner and with high affinity in the sub-micromolar range. The present study provides the first biochemical characterization of a purified full-length mammalian copper-transporting P-type ATPase associated with a human disease.

The design and implementation of an active replication scheme for distributing services in a cluster of workstations

Replication is the key to providing high availability, fault tolerance, and enhanced performance in a cluster of workstations (COWs). However, building such a system remains as a difficult and challenging task, mainly due to the difficulty of maintaining data consistency among replicas and the lack of easy and efficient tools supporting the development procedure. In this paper we propose an active replication scheme in which data consistency can be maintained. Based on the active replication scheme, we present an object-oriented design pattern and a constructing tool to simplify the design and implementation of service replications in COWs.

Implementation of student active learning in primary mathematics in Indonesia

Twenty years after the first pilot projects began to develop Student Active Learning (SAL) in Indonesia, and four years since it was adopted for use in the last provinces, this research investigates the implementation of Student Active Learning in Indonesian primary mathematics classrooms. A study of the relevant literature indicates that teaching based on constructivist principles is unlikely to be implemented well in mathematics classrooms unless there are high quality teachers, readily available manipulative materials, and a supportive learning environment. As Indonesian schools often lack one or more of these aspects, it seemed likely that Student Active Learning principles might not be ‘fully’ implemented in Indonesian primary mathematics classrooms. Thus a smaller scale, parallel study was carried out in Australian schools where there is no policy of Student Active Learning, but where its underlying principles are compatible with the stated views about learning and teaching mathematics. The study employed a qualitative interpretive methodology. Sixteen primary teachers from four urban and four rural Indonesian schools and four teachers from two Victorian schools were observed for four mathematics lessons each. The twenty teachers, as well as fourteen Indonesian headteachers and other education professionals, were interviewed in order to establish links between the background and beliefs of participants, and their implementation of Student Active Learning. Information on perceived constraints on the implementation of SAL was also sought. The results of this study suggest that Student Active learning has been implemented at four levels in Indonesian primary mathematics classrooms, ranging from essentially no implementation to a relatively high level of implementation, with an even higher level of implementation in three of the four Australian classrooms observed. Indonesian teachers, headteachers and supervisors hold a range of views of SAL and also of mathematics learning and teaching. These views largely depended on their in-service training in SAL and, more particularly, on their participation in the PEQIP project Typically, participants’ expressed views of SAL were at the same or higher level as their views of mathematics learning and teaching, with a similar pattern being observed in the relationship between these latter views and their implementation of SAL principles. Three factors were identified as influencing teacher change in terms of implementation of SAL: policy, curricular and organisational, and attitudes. Recommendations arising from this study include the adoption of reflection as an underlying principle in the theory of SAL, the continuation and extension of PEQIP type projects, changes in government policy on curriculum coverage and pre-service teacher training, and more support for teachers at the school and local authority levels.

Changes in zinc ligation promote remodeling of the active site in the zinc hydrolase superfamily

The zinc hydrolase superfamily is a group of divergently related proteins that are predominantly enzymes with a zinc-based catalytic mechanism. The common structural scaffold of the superfamily consists of an eight-stranded β-sheet flanked by six α-helices. Previous analyses, while acknowledging the likely divergent origins of leucine aminopeptidase, carboxypeptidase A and the co-catalytic enzymes of the metallopeptidase H clan based on their structural scaffolds, have failed to find any homology between the active sites in leucine aminopeptidase and the metallopeptidase H clan enzymes. Here we show that these two groups of co-catalytic enzymes have overlapping dizinc centers where one of the two zinc atoms is conserved in each group. Carboxypeptidase A and leucine aminopeptidase, on the other hand, no longer share any homologous zinc-binding sites. At least three catalytic zinc-binding sites have existed in the structural scaffold over the period of history defined by available structures. Comparison of enzyme-inhibitor complexes show that major remodeling of the substrate-binding site has occurred in association with each change in zinc ligation in the binding site. These changes involve re-registration and re-orientation of the substrate. Some residues important to the catalytic mechanism are not conserved amongst members. We discuss how molecules acting in trans may have facilitated the mutation of catalytically important residues in the active site in this group.

Evaluating the feasibility, effectiveness and acceptability of an active play intervention for disadvantaged preschool children : a pilot study

Australian children from disadvantaged families are at increased risk of delays in acquiring fundamental movement skills, with physical inactivity and increased risk of the potential consequences of obesity. The aims of this pilot study were to: 1) assess the fundamental movement skills of disadvantaged children; 2) evaluate the feasibility and effectiveness of adapting an existing parenting and child development program to incorporate additional weekly play activities (the intervention); and 3) examine the acceptability of the intervention. Children aged 1.5-5 years were assessed pre-intervention (n = 26) and postintervention (n = 16) over a period of 22 weeks using the gross motor component of the Peabody Developmental Motor Scales - 2nd Edition (PDMS-2) (Folio & Fewell, 2000). Parents completed a demographic and environmental survey and those implementing the intervention were interviewed to assess the feasibility and acceptability of the intervention. Pre-intervention the children from disadvantaged families had locomotion, object manipulation and Gross Motor Quotient (GMQ) scores significantly below the norm-referenced standards of the PDMS-2 (p < 0.05). The intervention was associated with improvements in the locomotion (8.35 to 9.5; p = 0.009), and object manipulation (8.6 to 9.6; p = 0.04) subtest scores and the GMQ scores (92.6 to 99.3; p < 0.01). The intervention was deemed feasible and acceptable by those implementing the program. Low levels of physical activity in disadvantaged communities may be related to delayed acquisition of fundamental movement skills in childhood. This pilot study raises the possibility of correcting this deficit in early childhood, and improving the potential for all children to lead an active life.

Characteristics of physically active and inactive men from low socioeconomic communities and housing estates : a qualitative study using the socioecological model

This qualitative study compares experiences of men from low socioeconomic status (SES) communities who achieved sufficient physical activity (PA) with those who did not. The socioecological model of health guided interviews with men (n=25) and community health workers (n=4) to explore individual, interpersonal, organizational, community, environmental and policy influences on PA participation. Men generally reported that they had poor health, financial barriers, were unfamiliar with community PA facilities and programs, had limited social support, and lived in unsafe neighbourhoods. There were clear differences between active and inactive men. Inactive men described their inability to cope with poor health, and consequent perceptions of disconnection. They did not identify positive PA outcomes and seemed consumed by stressful life situations. Active men identified barriers to existing programs such as the exclusive culture of PA facilities. It is important that personal circumstances are understood, and financial and cultural barriers addressed to promote PA among men from low SES communities.

Research methodologies in creative practice : literacy in the digital age of the twenty first century - learning from computer games

Literacy remains one of the central goals of schooling, but the ways in which it is understood are changing. The growth of the networked society, and the spread of Information and Communications Technologies (ICT), has brought about significant changes to traditional forms of literacy. Older, print based forms now take their place alongside a mix of newer multi-modal forms, where a wide range of elements such as image, sound, movement, light, colour and interactivity often supplant the printed word and contribute to the ways in which meaning is made. For young people to be fully literate in the twenty-first century, they need to have clear understandings about the ways in which these forms of literacy combine to persuade, present a point of view, argue a case or win the viewers’ sympathies. They need to know how to use them themselves, and to be aware of the ways in which others use them. They need to understand how digital texts organise and prioritise knowledge and information, and to recognise and be critically informed about the global context in which this occurs. That is, to be effective members of society, students need to become critical and capable users of both print and multimodal literacy, and be able to bring informed and analytic perspectives to bear on all texts, both print and digital, that they encounter in everyday life.

This is part of schools’ larger challenge to build robust connections between school and the world beyond, to meet the needs of all students, and to counter problems of alienation and marginalisation, particularly amongst students in the middle years. This means finding ways to be relevant and useful for all students, and to provide them with the skills and knowledge they will need in the ICT-based world of the Twentyfirst century. With respect to literacy education, engagement and technology, we urgently need more information as to how this might be best achieved.