92,971 results

  • Age-associated changes in VO2 and power output - A cross-sectional study of endurance trained New Zealand cyclists

    Brown, SJ; Ryan, HJ; Brown, Julie (2007-12)

    Journal article
    The University of Auckland Library

    Age-associated changes in power and maximal oxygen consumption (VO2max) were studied in a cross section of endurance trained cyclists. Subjects (n = 56) performed incremental cycling exercise, during which capillary blood lactate [La-] was measured. Power output increased by 30 Watts during each 5 minutes stage, with initial power output based on individual ability. When [La-] was >4.5 mmol??L-1, subjects were given a 10 min recovery at a power output approximately 50% below estimated power at [La-]4mmol. Subjects then performed an incremental test (1 minute stages) to VO2max. Decline in VO2max was 0.65 ml??kg-1??min-1??year-1 (r = -0.72, p < 0.01) for males, and 0.39 ml??kg-1??min-1??year-1 (r = -0.54, p < 0.05) for females. Power at VO2max decreased by 0.048 W kg-1??year-1 (r = -0.72, p < 0.01) in males. Power at [La-]4mmol decreased by 0.044 W kg-1??year-1 (r = -0.76, p < 0.01) in males, and by 0.019 W kg-1??year-1 (r = -0.53, p < 0.05) in females. Heart rate at VO2max (HRmax) showed a weaker correlation with age in males (r = -0.36, p < 0.05). The age-associated changes in maximum aerobic power and sub-maximal power were gender- specific, thus suggesting different age-related effects on the systems which support exercise in males and females.

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  • Cardiac vagal control and respiratory sinus arrhythmia during hypercapnia in humans

    Brown, SJ; Mundel, T; Brown, Julie (2007-12)

    Journal article
    The University of Auckland Library

    Normoxic hypercapnia may increase high-frequency (HF) power in heart rate variability (HRV) and also increase respiratory sinus arrhythmia (RSA). Low-frequency (LF) power may remain unchanged. In this study, 5-min ECG recordings (N = 10) were analyzed in time and frequency domains while human subjects breathed normoxic 5% CO2 (5%CO2) or room air (RA). Tidal volume (VT), inhalatory (TI), and exhalatory (TE) times of breaths in the final minute were measured. ECG time domain measures were unaffected by CO2 inhalation (P > 0.05). Following natural logarithmic transformation (LN), LFLN was unaltered (RA: 7.14 ?? 0.95 vs. 5%CO2: 7.35 ?? 1.12, P > 0.05), and HFLN increased (RA: 7.65 ?? 1.37 vs. 5%CO2: 8.58 ?? 1.11, P < 0.05) with CO2 inhalation. When changes in total power (NU) were corrected, LFNU decreased (RA: 34.4 ?? 22.9 vs. 5%CO2: 23.8 ?? 23.1, P < 0.01), and HFNU increased (RA: 56.5 ?? 22.3 vs. 5%CO2: 66.8 ?? 22.9, P < 0.01) with CO2 inhalation. TI (RA: 2.0 ?? 1.0 vs. 5%CO2: 1.9 ?? 0.8 s) and TE (RA: 2.5 ?? 1.1 vs. 5%CO2: 2.4 ?? 0.9 s) remained unchanged, but VT increased with CO2 inhalation (RA: 1.1 ?? 0.3 vs. 5%CO2: 2.0 ?? 0.8 L, P < 0.001). Heart rates during inhalation (RA: 35.2 ?? 4.4, 5%CO2: 34.5 ?? 4.8 beats min???1) were different from heart rates during exhalation (RA: 28.8 ?? 4.4, 5%CO2: 29.1 ?? 3.1 beats min???1). Hypercapnia did not increase the clustering of heart beats during inhalation, and we suggest that the HF component may not adequately reflect RSA.

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  • Age-related decline in mitochondrial DNA copy number in isolated human pancreatic islets.

    Cree, Lynsey; Patel, SK; Pyle, A; Lynn, S; Turnbull, DM; Chinnery, PF; Walker, M (2008-08)

    Journal article
    The University of Auckland Library

    Pancreatic beta cell function has been shown to decline with age in man. Depletion of mitochondrial DNA (mtDNA) copy number is associated with impaired insulin secretion in pancreatic beta cell lines, and decreased mtDNA copy number has been observed with age in skeletal muscle in man. We investigated whether mtDNA copy number decreases with age in human pancreatic beta cells, which might in turn contribute to the age-related decline in insulin secretory capacity.

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  • Pronuclear transfer in human embryos to prevent transmission of mitochondrial DNA disease.

    Craven, L; Tuppen, HA; Greggains, GD; Harbottle, SJ; Murphy, JL; Cree, Lynsey; Murdoch, AP; Chinnery, PF; Taylor, RW; Lightowlers, RN; Herbert, M; Turnbull, DM (2010-05-06)

    Journal article
    The University of Auckland Library

    Mutations in mitochondrial DNA (mtDNA) are a common cause of genetic disease. Pathogenic mutations in mtDNA are detected in approximately 1 in 250 live births and at least 1 in 10,000 adults in the UK are affected by mtDNA disease. Treatment options for patients with mtDNA disease are extremely limited and are predominantly supportive in nature. Mitochondrial DNA is transmitted maternally and it has been proposed that nuclear transfer techniques may be an approach for the prevention of transmission of human mtDNA disease. Here we show that transfer of pronuclei between abnormally fertilized human zygotes results in minimal carry-over of donor zygote mtDNA and is compatible with onward development to the blastocyst stage in vitro. By optimizing the procedure we found the average level of carry-over after transfer of two pronuclei is less than 2.0%, with many of the embryos containing no detectable donor mtDNA. We believe that pronuclear transfer between zygotes, as well as the recently described metaphase II spindle transfer, has the potential to prevent the transmission of mtDNA disease in humans.

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  • Crystal structures of F-420-dependent glucose-6-phosphate dehydrogenase FGD1 involved in the activation of the anti-tuberculosis drug candidate PA-824 reveal the basis of coenzyme and substrate binding

    Bashiri, Ghader; Squire, Christopher; Moreland, Nicole; Baker, Edward (2008)

    Journal article
    The University of Auckland Library

    The modified flavin coenzyme F420 is found in a restricted number of microorganisms. It is widely distributed in mycobacteria, however, where it is important in energy metabolism, and in Mycobacterium tuberculosis (Mtb) is implicated in redox processes related to non-replicating persistence. In Mtb, the F420- dependent glucose-6-phosphate dehydrogenase FGD1 provides reduced F420 for the in vivo activation of the nitroimidazopyran prodrug PA-824, currently being developed for anti-tuberculosis therapy against both replicating and persistent bacteria. The structure of M. tuberculosis FGD1 has been determined by x-ray crystallography both in its apo state and in complex with F420 and citrate at resolutions of 1.90 and 1.95 A?? , respectively. The structure reveals a highly specific F420 binding mode, which is shared with several other F420-dependent enzymes. Citrate occupies the substrate binding pocket adjacent to F420 and is shown to be a competitive inhibitor (IC50 43 M). Modeling of the binding of the glucose 6-phosphate (G6P) substrate identifies a positively charged phosphate binding pocket and shows that G6P, like citrate, packs against the isoalloxazine moiety of F420 and helps promote a butterfly bend conformation that facilitates F420 reduction and catalysis.

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  • The Corynebacterium diphtheriae shaft pilin SpaA is built of tandem Ig-like modules with stabilizing isopeptide and disulfide bonds

    Kang, HJ; Paterson, Neil; Gaspar, AH; Ton-That, H; Baker, Edward (2009)

    Journal article
    The University of Auckland Library

    Cell-surface pili are important virulence factors that enable bacterial pathogens to adhere to specific host tissues and modulate host immune response. Relatively little is known about the structure of Gram-positive bacterial pili, which are built by the sortase-catalyzed covalent crosslinking of individual pilin proteins. Here we report the 1.6-?? resolution crystal structure of the shaft pilin component SpaA from Corynebacterium diphtheriae, revealing both common and unique features. The SpaA pilin comprises 3 tandem Ig-like domains, with characteristic folds related to those typically found in non-pilus adhesins. Whereas both the middle and the C-terminal domains contain an intramolecular Lys???Asn isopeptide bond, previously detected in the shaft pilins of Streptococcus pyogenes and Bacillus cereus, the middle Ig-like domain also harbors a calcium ion, and the C-terminal domain contains a disulfide bond. By mass spectrometry, we show that the SpaA monomers are cross-linked in the assembled pili by a Lys???Thr isopeptide bond, as predicted by previous genetic studies. Together, our results reveal that despite profound dissimilarities in primary sequences, the shaft pilins of Gram-positive pathogens have strikingly similar tertiary structures, suggesting a modular backbone construction, including stabilizing intermolecular and intramolecular isopeptide bonds.

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  • Rethinking the admission criteria to nursing school

    Boaz, S; Wang, G; Zhao, Y; Baker, Heather (2011)

    Journal article
    The University of Auckland Library

    The main objective of this study was to identify the best predictors for student achievements (Undergraduate Grade Point Average (UGPA)) in their first year in an undergraduate nursing programme. Data were acquired from the Tracking Project database which is held by the Faculty of Medical and Health Sciences at the University of Auckland. The data (n = 134) included information on student demographics, final year secondary school achievements (National Certificate of Educational Achievement Grade Point Average (NCEAGPA) & NCEA Credits), university admission ranking scores, and achievements in first year in the undergraduate nursing programme (UGPA). Linear regression models were used to identify the best predictors for first year students' UGPA in the nursing programme. The regression models suggest that the best predictor for the first year GPA is the NCEAGPA (beta = .488; R2(for the entire model) = .53), followed by the admission ranking scores (beta = .308; R2 = .40). Based on these findings, it is suggested that a Dual Admission Model (DAM) be utilised whereby students could be admitted either by the current university admission criteria or by an alternative model, which is purely based on the predictability of achievement within the nursing programme. Application of the DAM to other institutions/countries was discussed.

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  • Crystal structure and metal binding properties of the lipoprotein MtsA, responsible for iron transport in Streptococcus pyogenes

    Sun, X; Baker, Heather; Ge, R; Sun, H; He, QY; Baker, Edward (2009)

    Journal article
    The University of Auckland Library

    An ability to acquire iron is essential for the viability and growth of almost all organisms and in pathogenic bacteria is strongly correlated with virulence. The cell surface lipoprotein MtsA, a component of the MtsABC transporter of Streptococcus pyogenes, acts as the primary receptor for inorganic iron by this significant human pathogen. Iron is bound as Fe2+, with the participation of bicarbonate. The crystal structure of MtsA has been determined and refined at 1.8A ?? resolution (R=0.167, and Rfree=0.194). MtsA has the classic bacterial metal binding receptor (MBR) fold, with the Fe2+ ion bound to the side chains of His68, His140, Glu206, and Asp281, at a totally enclosed site between the two domains of the protein. The absence of bicarbonate from the binding site suggests that it is displaced during the final stages of metal binding. Both the fold and metal binding site are most similar to those of the manganese receptors PsaA and MntC, consistent with the similar coordination requirements of Fe2+ and Mn2+. Binding studies confirm a 10-fold preference for Fe2+ over Mn2+, although both may be carried in vivo. Mutational analysis of the binding site shows that His140 is critical for a fully functional binding site but that Glu206 is dispensable. The crystal structure explains the distinct roles of these ligands and also reveals potential secondary binding sites that may explain the binding behavior of MtsA for metal ions other than Fe2+.

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  • The crystal structure of staphylococcal superantigen-like protein 11 (SSL11) in complex with sialyl Lewis X reveals the mechanism for cell binding and immune inhibition.

    Chung, MC; Wines, BD; Baker, Heather; Langley, Ries; Baker, Edward; Fraser, John (2007)

    Journal article
    The University of Auckland Library

    Staphylococcus aureus is a major pathogen that produces a family of 14 staphylococcal superantigen-like (SSL) proteins, which are structurally similar to superantigens but do not stimulate T cells. SSL11 is one member of the family that is found in all staphylococcal strains. Recombinant SSL11 bound to granulocytes and monocytes through a sialic aciddependent mechanism and was rapidly internalized. SSL11 also bound to sialic acid-containing glycoproteins, such as the Fc receptor for IgA (FcaRI) and P-selectin glycoprotein ligand-1 (PSGL-1), and inhibited neutrophil attachment to a P-selectin-coated surface. Biosensor analysis of two SSL11 alleles binding to sialyl Lewis X [sLex ??? Neu5Aca2-3Galb1- 4(Fuc1-3)GlcNAc] coupled to bovine serum albumin gave dissociation constants of 0.7 and 7 mm respectively. Binding of SSL11 to a glycan array revealed specificity for glycans containing the trisaccharide sialyllactosamine (sLacNac ??? Neu5Aca2- 3Galb1-4GlcNAc). A 1.6 ?? resolution crystal structure of SSL11 complexed with sLex revealed a discrete binding site in the C-terminal b-grasp domain, with predominant interactions with the sialic acid and galactose residues. A single amino acid mutation in the carbohydrate binding site abolished all SSL11 binding. Thus, SSL11 is a staphylococcal protein that targets myeloid cells by binding sialyllactosaminecontaining glycoproteins.

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  • Crystal structures of the Staphylococcal toxin SSL5 complex with sialyl-Lewis X revel conserved binding site that shares common features with viral and bacterial sialic acid-binding proteins.

    Baker, Heather; Basu, I; Chung, MC; Caradoc-Davies, TT; Fraser, John; Baker, Edward (2007)

    Journal article
    The University of Auckland Library

    Staphylococcus aureus is a significant human pathogen. Among its large repertoire of secreted toxins is a group of staphylococcal superantigen-like proteins (SSLs). These are homologous to superantigens but do not have the same activity. SSL5 is shown here to bind to human granulocytes and to the cell surface receptors for human IgA (Fc??RI) and P-selectin [P-selectin glycoprotein ligand-1 (PSGL-1)] in a sialic acid (Sia)-dependent manner. Cocrystallization of SSL5 with the tetrasaccharide sialyl Lewis X (sLeX), a key determinant of PSGL-1 binding to P-selectin, led to crystal structures of the SSL5???sLeX complex at resolutions of 1.65 and 2.75 ?? for crystals at two pH values. In both structures, sLeX bound to a specific site on the surface of the C-terminal domain of SSL5 in a conformation identical with that bound by P-selectin. Conservation of the key carbohydrate binding residues indicates that this ability to bind human glycans is shared by a substantial subgroup of the SSLs, including SSL2, SSL3, SSL4, SSL5, SSL6, and SSL11. This indicates that the ability to target human glycans is an important property of this group of toxins. Structural comparisons also showed that the Sia binding site in SSL5 contains a substructure that is shared by other Sia binding proteins from bacteria as well as viruses and represents a common binding motif.

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  • Performance analysis of liquid desiccant dehumidification systems

    Jain, S; Bansal, Pradeep (2007)

    Journal article
    The University of Auckland Library

    Desiccant systems find applications in a very large variety of industrial and daily usage products including the new HVAC installations. An overview of liquid desiccant technology has been presented in this paper along with a compilation of experimental performance data of liquid desiccant dehumidifiers, empirical dehumidification effectiveness and mass transfer correlations in a useful and easy to read tabular format. The latest trends in this area suggest that hybrid systems are of current interest to HVAC industry, not only for high latent load applications but also for improving indoor air quality. The paper presents a comprehensive comparative parametric analysis of packed bed dehumidifiers for three commonly used desiccant materials viz. triethylene glycol, lithium chloride and calcium chloride, using empirical correlations for dehumidification effectiveness from the literature. The analysis reveals significant variations and anomalies in trends between the predictions by various correlations for the same operating conditions, and highlights the need for benchmarking the performance of desiccant dehumidifiers.

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  • Narrative frames for investigating the experiences of language teachers

    Barkhuizen, Gary; Wette, Rosemary (2008)

    Journal article
    The University of Auckland Library

    the particular contexts in which they teach. This article reports on the use of narrative frames as a means of investigating the teaching experiences of university English teachers in China. This study used four specifically designed narrative frames to collect data from a large group of teachers who participated in a summer teacher education program. Eighty-three complete sets of the four frames were collected and then analyzed using a paradigmatic approach typical of qualitative content analysis to explore commonalities among the teachers??? experiences. One frame, relating to the Research Methodology course, is used to illustrate the effectiveness of this approach. The researchers suggest that the frames are useful for collecting a large amount of data from a large number of participants, and that they provide a means of entry into an unfamiliar research context. At the same time, they caution that using the frames in this way has the potential to de-personalize the experiences of teachers, an outcome atypical of narrative inquiry.

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  • Expression, purification and crystallization of native and selenomethionine labeled Mycobacterium tuberculosis FGD1(Rv0407) using a Mycobacterium smegmatis expression system.

    Bashiri, G; Squire, Christopher; Baker, Edward; Moreland, Nicole (2007)

    Journal article
    The University of Auckland Library

    FGD1 is an F420-dependent glucose-6-phosphate dehydrogenase from Mycobacterium tuberculosis that has been shown to be essential for activation of the anti-TB compound PA-824. Initial attempts to produce recombinant FGD1 using Escherichia coli as a host was unsuccessful, but when the alternative host Mycobacterium smegmatis was used, soluble protein yields of 7 mg/L of culture were achieved. Both native and selenomethionine-substituted FGD1 were obtained by culturing M. smegmatis in autoinduction media protocols originally developed for E. coli. Using these media afforded the advantages of decreased handling, as cultures did not require monitoring of optical density and induction, and reduced cost by removing the need for expensive ADC enrichment normally used in mycobacterial cultures. Selenomethionine was efficiently incorporated at levels required for multiwavelength anomalous diffraction experiments used in crystal structure determination. As far as we are aware this is the first protocol for preparation of selenomethionine- substituted protein in mycobacteria. Native and selenomethionine-labeled FGD1 were successfully crystallized by vapor diffusion, with the crystals diffracting to 2.1A ?? resolution.

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  • Evaluating the outcomes of plans: theory, practice, and methodology

    Beattie, Lee; Laurian, L; Crawford, J; Mason, G; Ericksen, N; Kouwenhoven, P; Day, M (2010)

    Journal article
    The University of Auckland Library

    Despite calls for performance-oriented and evidence-based planning, the outcomes of land use and environmental plans are rarely monitored or assessed ex post facto (that is, post implementation). As a result, planners cannot know whether or why plans achieve their goals, or learn from the results of past interventions to improve planning practice. This evaluation gap is caused by a lack of methodology to evaluate the outcomes of plans and the difficulty of attributing changes to planning activities. We address this gap by proposing and testing a plan-outcome evaluation (POE) methodology. We demonstrate its broad applicability and usefulness in the context of local plans in New Zealand. The POE methodology will be useful to practitioners and academics seeking to assess the outcomes of plans in countries with western planning traditions.

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  • Rapid adaptation to food availability by a dopamine-mediated morphogenetic response

    Adams, DK; Sewell, MA; Angerer, RC; Angerer, LM (2011)

    Journal article
    The University of Auckland Library

    Food can act as a powerful stimulus, eliciting metabolic, behavioural and developmental responses. These phenotypic changes can alter ecological and evolutionary processes; yet, the molecular mechanisms underlying many plastic phenotypic responses remain unknown. Here we show that dopamine signalling through a type-D2 receptor mediates developmental plasticity by regulating arm length in pre-feeding sea urchin larvae in response to food availability. Although prey-induced traits are often thought to improve food acquisition, the mechanism underlying this plastic response acts to reduce feeding structure size and subsequent feeding rate. Consequently, the developmental programme and/or maternal provisioning predetermine the maximum possible feeding rate, and food-induced dopamine signalling reduces food acquisition potential during periods of abundant resources to preserve maternal energetic reserves. Sea urchin larvae may have co-opted the widespread use of food-induced dopamine signalling from behavioural responses to instead alter their development.

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  • The Effect of Ocean Acidification on Calcifying Organisms in Marine Ecosystems: An Organism-to-Ecosystem Perspective

    Hofmann, GE; Barry, JP; Edmunds, PJ; Gates, RD; Hutchins, DA; Klinger, T; Sewell, Mary (2010)

    Journal article
    The University of Auckland Library

    Ocean acidification (OA), a consequence of anthropogenic carbon dioxide emissions, poses a serious threat to marine organisms in tropical, openocean, coastal, deep-sea, and high-latitude sea ecosystems. The diversity of taxonomic groups that precipitate calcium carbonate from seawater are at particularly high risk. Here we review the rapidly expanding literature concerning the biological and ecological impacts of OA on calcification, using a cross-scale, process-oriented approach. In comparison to calcification, we find that areas such as fertilization, early life-history stages, and interaction with synergistic stressors are understudied. Although understanding the long-term consequences ofOAare critical, available studies are largely shortterm experiments that do not allow for tests of long-term acclimatization or adaptation. Future research on the phenotypic plasticity of contemporary organisms and interpretations of performance in the context of current environmental heterogeneity of pCO2 will greatly aid in our understanding of how organisms will respond to OA in the future.

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  • Functions for pro-opiomelanocortin-derived peptides in obesity and diabetes 1997 - 2009

    Mountjoy, Kathleen (2010)

    Journal article
    The University of Auckland Library

    Melanocortin peptides, derived from POMC (pro-opiomelanocortin) are produced in the ARH (arcuate nucleus of the hypothalamus) neurons and the neurons in the commissural NTS (nucleus of the solitary tract) of the brainstem, in anterior and intermediate lobes of the pituitary, skin and a wide range of peripheral tissues, including reproductive organs. A hypothetical model for functional roles of melanocortin receptors in maintaining energy balance was proposed in 1997. Since this time, there has been an extraordinary amount of knowledge gained about POMC-derived peptides in relation to energy homoeostasis. Development of a Pomc-null mouse provided definitive proof that POMC-derived peptides are critical for the regulation of energy homoeostasis. The melanocortin system consists of endogenous agonists and antagonists, five melanocortin receptor subtypes and receptor accessory proteins. The melanocortin system, as is now known, is far more complex than most of us could have imagined in 1997, and, similarly, the importance of this system for regulating energy homoeostasis in the general human population is much greater than we would have predicted. Of the known factors that can cause human obesity, or protect against it, the melanocortin system is by far the most significant. The present review is a discussion of the current understanding of the roles and mechanism of action of POMC, melanocortin receptors and AgRP (agouti-related peptide) in obesity and Type 2 diabetes and how the central and/or peripheral melanocortin systems mediate nutrient, leptin, insulin, gut hormone and cytokine regulation of energy homoeostasis.

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  • Fashion waves in information systems research and practice

    Baskerville, RL; Myers, Michael (2009)

    Journal article
    The University of Auckland Library

    Building on neo-institutional theory and theories of innovation and diffusion, recent work in the field of management has suggested that management research and practice is characterized by fashions. A management fashion is a relatively transitory belief that a certain management technique leads rational management progress. Using bibliographic research, we apply Abrahamson's management fashion theory to information systems research and practice. Our findings reveal that information systems research and practice, like management research and practice, is indeed characterized by fashions. These "IS fashion waves" are relatively transitory and represent a burst of interest in particular topics by IS researchers and practitioners. However, while our findings show that IS research closely parallels practice, we suggest that a more proactive engagement of IS academics is needed in the IS fashion-setting process.

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  • The Effect of Board Characteristics on Firm Environmental Performance

    De Villiers, Charl; Naiker, Vicky; Van Staden, C (2011)

    Journal article
    The University of Auckland Library

    This study investigates the relationship between strong firm environmental performance and board characteristics that capture boards??? monitoring and resource provision abilities during an era when the natural environment and the related strategic opportunities have increased in importance. The authors relate the proxy for strong environmental performance to board characteristics that represent boards??? monitoring role (i.e., independence, CEO-chair duality, concentration of directors appointed after the CEO, and director shareholding) and resource provision role (i.e., board size, directors on multiple boards, CEOs of other firms on the board, lawyers on the board, and director tenure). The authors provide evidence consistent with both theories of board roles. Specifically, consistent with their agency theory???driven predictions, the authors find evidence of higher environmental performance in firms with higher board independence and lower concentration of directors appointed after the CEO on the board of directors. Consistent with resource dependence theory, they show that environmental performance is higher in firms that have larger boards, larger representation of active CEOs on the board, and more legal experts on the board. Their findings are generally robust to a number of sensitivity analyses. These findings have implications for managers, firms, shareholders, and regulators who act on behalf of shareholders, if they are interested in influencing environmental performance.

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  • Drift and breakup of spiral waves in reaction-diffusion-mechanics systems

    Panfilov, AV; Keldermann, RH; Nash, Martyn (2007)

    Journal article
    The University of Auckland Library

    Rotating spiral waves organize excitation in various biological, physical, and chemical systems. They underpin a variety of important phenomena, such as cardiac arrhythmias, morphogenesis processes, and spatial patterns in chemical reactions. Important insights into spiral wave dynamics have been obtained from theoretical studies of the reaction???diffusion (RD) partial differential equations. However, most of these studies have ignored the fact that spiral wave rotation is often accompanied by substantial deformations of the medium. Here, we show that joint consideration of the RD equations with the equations of continuum mechanics for tissue deformations (RD???mechanics systems), yield important effects on spiral wave dynamics. We show that deformation can induce the breakup of spiral waves into complex spatiotemporal patterns. We also show that mechanics leads to spiral wave drift throughout the medium approaching dynamical attractors, which are determined by the parameters of the model and the size of the medium. We study mechanisms of these effects and discuss their applicability to the theory of cardiac arrhythmias. Overall, we demonstrate the importance of RD???mechanics systems for mathematics applied to life sciences.

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