Geometry in the Transition from Primary to Post-Primary

This article is intended as a kind of precursor to the document Geometry for Post-primary School Mathematics, part of the Mathematics Syllabus for Junior Certicate issued by the Irish National Council for Curriculum and Assessment in the context of Project Maths. Our purpose is to place that document in the context of an overview of plane geometry, touching on several important pedagogical and historical aspects, in the hope that this will prove useful for teachers.Comment: 19 page

The impact of hospital accreditation on quality measures:An interrupted time series analysis

BACKGROUND: Developing countries frequently use hospital accreditation to guarantee quality and patient safety. However, implementation of accreditation standards is demanding on organisations. Furthermore, the empirical literature on the benefits of accreditation is sparse and this is the first empirical interrupted time series analysis designed to examine the impact of healthcare accreditation on hospital quality measures. METHODS: The study was conducted in a 150-bed multispecialty hospital in Abu Dhabi, United Arab Emirates. The quality performance outcomes were observed over a 48 month period. The quality performance differences were compared across monthly intervals between two time segments, 1 year pre- accreditation (2009) and 3 years post-accreditation (2010, 2011 and 2012) for the twenty-seven quality measures. The principal data source was a random sample of 12,000 patient records drawn from a population of 50,000 during the study period (January 2009 to December 2012). Each month (during the study period), a simple random sample of 24 percent of patient records was selected and audited, resulting in 324,000 observations. The measures (structure, process and outcome) are related to important dimensions of quality and patient safety. RESULTS: The study findings showed that preparation for the accreditation survey results in significant improvement as 74% of the measures had a significant positive pre-accreditation slope. Accreditation had a larger significant negative effect (48% of measures) than a positive effect (4%) on the post accreditation slope of performance. Similarly, accreditation had a larger significant negative change in level (26%) than a positive change in level (7%) after the accreditation survey. Moreover, accreditation had no significant impact on 11 out of the 27 measures. However, there is residual benefit from accreditation three years later with performance maintained at approximately 90%, which is 20 percentage points higher than the baseline level in 2009. CONCLUSIONS: Although there is a transient drop in performance immediately after the survey, this study shows that the improvement achieved from accreditation is maintained during the three year accreditation cycle

Rho-dependent control of anillin behavior during cytokinesis

Anillin is a conserved protein required for cytokinesis but its molecular function is unclear. Anillin accumulation at the cleavage furrow is Rho guanine nucleotide exchange factor (GEF)Pbl–dependent but may also be mediated by known anillin interactions with F-actin and myosin II, which are under RhoGEFPbl-dependent control themselves. Microscopy of Drosophila melanogaster S2 cells reveal here that although myosin II and F-actin do contribute, equatorial anillin localization persists in their absence. Using latrunculin A, the inhibitor of F-actin assembly, we uncovered a separate RhoGEFPbl-dependent pathway that, at the normal time of furrowing, allows stable filamentous structures containing anillin, Rho1, and septins to form directly at the equatorial plasma membrane. These structures associate with microtubule (MT) ends and can still form after MT depolymerization, although they are delocalized under such conditions. Thus, a novel RhoGEFPbl-dependent input promotes the simultaneous association of anillin with the plasma membrane, septins, and MTs, independently of F-actin. We propose that such interactions occur dynamically and transiently to promote furrow stability

Hierarchical priority setting for restoration in a watershed in NE Spain, based on assessments of soil erosion and ecosystem services

31 páginas[EN] Maintaining and enhancing ecosystem services through the restoration of degraded ecosystems have become an important biodiversity conservation strategy. Deciding where to restore ecosystems for the attainment of multiple services is a key issue for future planning, management, and human well-being. Most restoration projects usually entail a small number of actions in a local area and do not consider the potential benefits of planning restoration at broad regional scales. We developed a hierarchical priority setting approach to evaluate the performance of restoration measures in a semiarid basin in NE Spain (the Martín River Basin, 2,112 km2). Our analysis utilized a combination of erosion (a key driver of degradation in this Mediterranean region) and six spatially explicit ecosystem services data layers (five of these maps plotted surrogates for soil retention and accumulation, water supply and regulation, and carbon storage, and one plotted a cultural service, ecotourism). Hierarchical maps were generated using a geographic information system that combined areas important for providing a bundle of ecosystem services, as state variables, with erosion maps, as the disturbance or regulatory variable. This was performed for multiple scales, thereby identifying the most adequate scale of analysis and establishing a spatial hierarchy of restoration actions based on the combination of the evaluation of erosion rates and the provision of ecosystem services. Our approach provides managers with a straightforward method for determining the spatial distribution of values for a set of ecosystem services in relation to ecological degradation thresholds and for allocating efforts and resources for restoration projects in complex landscapes.This work was funded by Endesa S.A. through the collaborative agreement Endesa-CSIC for scientific research. The first author wants to thank Belinda Reyers for the fruitful conversation and helpfulness showed in every moment and two anonymous referees for their constructive suggestions. M. Trabucchi was in receipt of grant from JAE-DOC Program for Advanced Study financed by the European Social Fund (ESF), Ref. I3P-BPD-2006.Peer reviewe

Rux is a cyclin-dependent kinase inhibitor (CKI) specific for mitotic cyclin–Cdk complexes

AbstractBackground: Roughex (Rux) is a cell-cycle regulator that contributes to the establishment and maintenance of the G1 state in the fruit fly Drosophila. Genetic data show that Rux inhibits the S-phase function of the cyclin A (CycA)–cyclin-dependent kinase 1 (Cdk1) complex; in addition, it can prevent the mitotic functions of CycA and CycB when overexpressed. Rux has no homology to known Cdk inhibitors (CKIs), and the molecular mechanism of Rux function is not known.Results: Rux interacted with CycA and CycB in coprecipitation experiments. Expression of Rux caused nuclear translocation of CycA and CycB, and inhibited Cdk1 but not Cdk2 kinase activity. Cdk1 inhibition by Rux did not rely on inhibitory phosphorylation, disruption of cyclin–Cdk complex formation or changes in subcellular localization. Rux inhibited Cdk1 kinase in two ways: Rux prevented the activating phosphorylation on Cdk1 and also inhibited activated Cdk1 complexes. Surprisingly, Rux had a stimulating effect on CycA–Cdk1 activity when present in low concentrations.Conclusions: Rux fulfils all the criteria for a CKI. This is the first description in a multicellular organism of a CKI that specifically inhibits mitotic cyclin–Cdk complexes. This function of Rux is required for the G1 state and male meiosis and could also be involved in mitotic regulation, while the stimulating effect of Rux might assist in any S-phase function of CycA–Cdk1

Mitotic Regulators Govern Progress through Steps in the Centrosome Duplication Cycle

Centrosome duplication is marked by discrete changes in centriole structure that occur in lockstep with cell cycle transitions. We show that mitotic regulators govern steps in centriole replication in Drosophila embryos. Cdc25string, the expression of which initiates mitosis, is required for completion of daughter centriole assembly. Cdc20fizzy, which is required for the metaphase-anaphase transition, is required for timely disengagement of mother and daughter centrioles. Stabilization of mitotic cyclins, which prevents exit from mitosis, blocks assembly of new daughter centrioles. Common regulation of the nuclear and centrosome cycles by mitotic regulators may ensure precise duplication of the centrosome

Involvement of an SCF(Slmb) complex in timely elimination of E2F upon initiation of DNA replication in Drosophila

BACKGROUND: Cul1 is a core component of the evolutionarily conserved SCF-type ubiquitin ligases that target specific proteins for destruction. SCF action contributes to cell cycle progression but few of the key targets of its action have been identified. RESULTS: We found that expression of the mouse Cul1 (mCul1) in the larval wing disc has a dominant negative effect. It reduces, but does not eliminate, the function of SCF complexes, promotes accumulation of Cubitus interruptus (a target of SCF action), triggers apoptosis, and causes a small wing phenotype. A screen for mutations that dominantly modify this phenotype showed effective suppression upon reduction of E2F function, suggesting that compromised downregulation of E2F contributes to the phenotype. Partial inactivation of Cul1 delayed the abrupt loss of E2F immunofluorescence beyond its normal point of downregulation at the onset of S phase. Additional screens showed that mild reduction in function of the F-box encoding gene slimb enhanced the mCul1 overexpression phenotype. Cell cycle modulation of E2F levels is virtually absent in slimb mutant cells in which slimb function is severely reduced. This implicates Slimb, a known targeting subunit of SCF, in E2F downregulation. In addition, Slimb and E2F interacted in vitro in a phosphorylation-dependent manner. CONCLUSION: We have used genetic and physical interactions to identify the G1/S transcription factor E2F as an SCF(Slmb )target in Drosophila. These results argue that the SCF(Slmb )ubiquitin ligase directs E2F destruction in S phase

Selections that isolate recombinant mitochondrial genomes in animals.

Homologous recombination is widespread and catalyzes evolution. Nonetheless, its existence in animal mitochondrial DNA is questioned. We designed selections for recombination between co-resident mitochondrial genomes in various heteroplasmic Drosophila lines. In four experimental settings, recombinant genomes became the sole or dominant genome in the progeny. Thus, selection uncovers occurrence of homologous recombination in Drosophila mtDNA and documents its functional benefit. Double-strand breaks enhanced recombination in the germline and revealed somatic recombination. When the recombination partner was a diverged Drosophila melanogaster genome or a genome from a different species such as Drosophila yakuba, sequencing revealed long continuous stretches of exchange. In addition, the distribution of sequence polymorphisms in recombinants allowed us to map a selected trait to a particular region in the Drosophila mitochondrial genome. Thus, recombination can be harnessed to dissect function and evolution of mitochondrial genome

A Genome-wide Screen Reveals that Reducing Mitochondrial DNA Polymerase Can Promote Elimination of Deleterious Mitochondrial Mutations.

A mutant mitochondrial genome arising amid the pool of mitochondrial genomes within a cell must compete with existing genomes to survive to the next generation. Even weak selective forces can bias transmission of one genome over another to affect the inheritance of mitochondrial diseases and guide the evolution of mitochondrial DNA (mtDNA). Studies in several systems suggested that purifying selection in the female germline reduces transmission of detrimental mitochondrial mutations [1-7]. In contrast, some selfish genomes can take over despite a cost to host fitness [8-13]. Within individuals, the outcome of competition is therefore influenced by multiple selective forces. The nuclear genome, which encodes most proteins within mitochondria, and all external regulators of mitochondrial biogenesis and dynamics can influence the competition between mitochondrial genomes [14-18], yet little is known about how this works. Previously, we established a Drosophila line transmitting two mitochondrial genomes in a stable ratio enforced by purifying selection benefiting one genome and a selfish advantage favoring the other [8]. Here, to find nuclear genes that impact mtDNA competition, we screened heterozygous deletions tiling ∼70% of the euchromatic regions and examined their influence on this ratio. This genome-wide screen detected many nuclear modifiers of this ratio and identified one as the catalytic subunit of mtDNA polymerase gene (POLG), tam. A reduced dose of tam drove elimination of defective mitochondrial genomes. This study suggests that our approach will uncover targets for interventions that would block propagation of pathogenic mitochondrial mutations