36 research outputs found
Synergy and Group Size in Microbial Cooperation
No full textMicrobes produce many molecules that are important for their growth and development, and the exploitation of these secretions by nonproducers has recently become an important paradigm in microbial social evolution. Although the production of these public-goods molecules has been studied intensely, little is known of how the benefits accrued and the costs incurred depend on the quantity of public-goods molecules produced. We focus here on the relationship between the shape of the benefit curve and cellular density, using a model assuming three types of benefit functions: diminishing, accelerating, and sigmoidal (accelerating and then diminishing). We classify the latter two as being synergistic and argue that sigmoidal curves are common in microbial systems. Synergistic benefit curves interact with group sizes to give very different expected evolutionary dynamics. In particular, we show that whether and to what extent microbes evolve to produce public goods depends strongly on group size. We show that synergy can create an "evolutionary trap" that can stymie the establishment and maintenance of cooperation. By allowing density-dependent regulation of production (quorum sensing), we show how this trap may be avoided. We discuss the implications of our results on experimental design.</p
Board monitoring and judgement as processes of sensemaking
No full textWhen organizational scandals occur, the common refrain among commentators is: 'Where was the board in all this?' 'How could the directors not have known what was going on?''Why didn't the board intervene?' The scandals demonstrate that board monitoring or oganizational performance is a matter of great importance. By monitoring, we mean the act of keeping the organization under review. In many English-speaking countries, directors have a legal duty of care, which includes duties to monitor the performance of their organizations (Hopt and von Hippel 2010). However, statutory law typically merely states the duty, while providing little guidance on how that duty can be met. \u
The catechol-O-methyltransferase (COMT) Val158Met polymorphism moderates the effect of antenatal stress on childhood behavioural problems: longitudinal evidence across multiple ages
No full textAim: The functional polymorphism Val158Met in the catechol-O-methyltransferase (COMT) gene was analysed to determine its association with maternal stress and childhood total difficulties.Method: Data were collected at birth from a group of infants who were born small for gestational age and a group who were born at an appropriate size for gestational age and had been enrolled in the Auckland Birthweight Collaborative Study. Children were followed up at the ages of 1 year, 3 years 6 months, 7 years, and 11 years. At the age of 11 years, DNA samples were collected from 546 children (270 females, 276 males): 227 children born small for gestational age and 319 children born at an appropriate size for gestational age. The main independent variable was perceived maternal stress at birth and at 7 and 11 years of age, assessed using the total difficulties scale of the Strength and Difficulties Questionnaire. IQ was assessed at the age of 7 years.Results: Met/Met homozygotes were at a significantly increased risk of behavioural and emotional problems at the ages of 7 (p=0.002) and 11 years (p=0.003), relative to either heterozygous or homozygous carriers of the Val158Met polymorphism, but only when they were exposed to maternal stress in utero. Met/Met homozygotes had, on average, IQ scores that were four points higher than those of Val/Val homozygotes (p=0.010).Interpretation: These findings emphasize the potential long-term consequences of prenatal stress for genetically susceptible individuals during neurodevelopment in utero. Our findings add to the general understanding of the aetiology and developmental nature of childhood emotional and behavioural problems.<br/
Children born small for gestational age are not at special risk for preschool emotion and behaviour problems
No full textDespite the wealth of literature examining long term outcomes of preterm low birthweight children, few studies have directly assessed the developmental impact of being born full term but small for gestational age (SGA). We aim to determine whether (i) being SGA increases preschool behavioural problems and (ii) other risk factors operate differently in SGA and appropriate for gestational age (AGA) controls. 550 New Zealand European mothers and their 3.5 year old children participated in this study. All children were born at full term (> 37 weeks' gestation) and approximately half were SGA (? sex specific 10th percentile for gestation) the remainder were AGA controls. Extensive data were collected at the child's birth, 1 year and 3.5 years. Behavioural problems were measured when children were 3.5 years, using the Strengths and Difficulties Questionnaire (SDQ). Multiple regression analyses were used to examine the associations between risk factors and behavioural problems; statistical weighting was used for analyses of the total study group. There was no significant difference in behavioural problems between SGA and AGA groups. In the total sample the significant predictors of behavioural problems included: mothers' school leaving age; smoking during pregnancy; maternal alcohol use during pregnancy; and absence of the father. Predictors of behavioural problems were found to be the same for SGA and AGA groups. These results do not support the view that SGA is a risk for behavioural preschool difficulties or that SGA children are sensitised to risks known to be associated with such difficulties in the preschool years.<br/
Initial evidence that polymorphisms in neurotransmitter-regulating genes contribute to being born small for gestational age
No full textBeing born small for gestational age (SGA) is a putative risk factor for the development of later cognitive and psychiatric health problems. While the inter-uterine environment has been shown to play an important role in predicting birth weight, little is known about the genetic factors that might be important. Here we test the hypothesis that neurotransmitter-regulating genes implicated in psychiatric disorders previously shown to be associated with SGA (such as attention-deficit hyperactivity disorder) are themselves predictive of SGA. DNA was collected from 227 SGA and 319 appropriate for gestational age children taking part in the Auckland Birthweight Collaborative Study. Candidate single nucleotide polymorphisms in genes regulating activity within dopamine, serotonin, glutamate and gamma-aminobutyric acid pathways were genotyped. Multiple regression analysis, controlling for potentially confounding factors, supported nominally significant associations between SGA and single nucleotide polymorphisms in COMT, HTR2A, SLC1A1 and SLC6A1. This is the first evidence that genes implicated in psychiatric disorders previously linked to SGA status themselves predict SGA. This highlights the possibility that the link between SGA and psychiatric disorders such as attention-deficit hyperactivity disorder may in part be genetically determined - that SGA marks pre-existing genetic risk for later problems. <br/
Relative proximity of chromosome territories influences chromosome exchange partners in radiation-induced chromosome rearrangements in primary human bronchial epithelial cells
No full textCopyright © 2013 The Authors. This article is made available through the Brunel Open Access Publishing Fund. This is an open access article distributed under the terms of the Creative Commons Attribution-NonCommercial-No Derivative Works License, which permits non-commercial use, distribution, and reproduction in any medium, provided the original author and source are credited.Copyright © 2013 The Authors. It is well established that chromosomes exist in discrete territories (CTs) in interphase and are positioned in a cell-type specific probabilistic manner. The relative localisation of individual CTs within cell nuclei remains poorly understood, yet many cancers are associated with specific chromosome rearrangements and there is good evidence that relative territorial position influences their frequency of exchange. To examine this further, we characterised the complexity of radiation-induced chromosome exchanges in normal human bronchial epithelial (NHBE) cells by M-FISH analysis of PCC spreads and correlated the exchanges induced with their preferred interphase position, as determined by 1/2-colour 2D-FISH analysis, at the time of irradiation. We found that the frequency and complexity of aberrations induced were reduced in ellipsoid NHBE cells in comparison to previous observations in spherical cells, consistent with aberration complexity being dependent upon the number and proximity of damaged CTs, i.e. lesion proximity. To ask if particular chromosome neighbourhoods could be identified we analysed all radiation-induced pair-wise exchanges using SCHIP (statistics for chromosome interphase positioning) and found that exchanges between chromosomes (1;13), (9;17), (9;18), (12;18) and (16;21) all occurred more often than expected assuming randomness. All of these pairs were also found to be either sharing similar preferred positions in interphase and/or sharing neighbouring territory boundaries. We also analysed a human small cell lung cancer cell line, DMS53, by M-FISH observing the genome to be highly rearranged, yet possessing rearrangements also involving chromosomes (1;13) and (9;17). Our findings show evidence for the occurrence of non-random exchanges that may reflect the territorial organisation of chromosomes in interphase at time of damage and highlight the importance of cellular geometry for the induction of aberrations of varying complexity after exposure to both low and high-LET radiation.Department of Healt
Collaborative research to support reflexive feminist professional work
No full textPossibilities for postmodern emergence [Somerville, M. (2007). Postmodern emergence. International Journal of Qualitative Studies in Education, 20(2), 225-243] in professional practice were explored by a group of tertiary educators working together on a collaborative memory project. This allowed new possibilities for informing and extending practice beyond taken-for-granted norms circumscribed by the neoliberal university environment. Each author branched off from an initial study to work further with their constituent professional groups: early childhood educators, teachers, counsellors and educational psychologists. The collaborative method involves theoretical provocations for analysing positionings within dominant discourses that shape contemporary educational practices, providing support for reflexive insight into professional work. Findings indicated the fruitfulness of collaborative support for theoretical explorations into diverse domains of inquiry relevant for practice. There were also challenges associated with collaborative theorising in the individualistic setting of the university, including difficulties in embracing group coherence without homogenising intra-group differences. This process could be used in other settings to renew the research, discoveries and future becomings of academic or professional selves
Whose future? Whose choosing?: Counselling in a context of (im)possible choice.
No full textCritically reflexive practice is at the heart of counselling, and even more so when clients come face to face with (im)possible choices. As counsellor educators, the authors show counselling practice at the edge of uncertainty. This article features a counselling context in a secondary school. It describes a fictional situation where action is called for in the midst of undecidability, at an impasse in the life of a young woman client. The article explores the aporia that confront the young woman and the counsellor, in the context of education, career, families, cultures and communities. The authors show that these explorations produced transformational questions for their teaching practice as counsellor educators
Parent and Teacher (Dis)Agreement on the Conners Rating Scale: Revised-Long Format
No full textThe Conners Rating Scale: Revised-Long version (CRS: R-L) has been used widely in clinic and research settings to measure child behavior and symptoms of attention deficit hyperac- tivity disorder (ADHD). Despite evidence of poor agreement between parent and teacher reports of child internalizing and externalizing problems, no study to date has examined the levels of agreement between parent and teacher reports of child behavior using the CRS: R-L. Our aim was to measure the level of agreement between parent and teacher perception of child emotion and behavior problems using the CRS: R-L. A total of 591 New Zealand European mothers and their 7-year-old children participated in Phase 4 of the Auckland Birthweight Collaborative (ABC) study. Child behavior was measured when the children were 7 years old using the parent and teacher versions of the CRS: R-L. Parent and teacher agreement was analyzed using weighted kappa coefficient, Pearson correlation coefficient, and Bland-Altman plots. Agreement between parent and teacher reports of child behavior was found to range between poor and low. Agreement decreased with reports of increasing behavioral problems and was generally higher for externalizing subscales and lower for in- ternalizing subscales
