932 research outputs found
Magma production and growth of the lava dome of the Soufriere Hills Volcano, Montserrat, West Indies: November 1995 to November 1997
High Proportion of Inflammatory Breast Cancer in the Population-Based Cancer Registry of Gharbiah, Egypt
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/72192/1/j.1524-4741.2009.00755.x.pd
Affordances, constraints and information flows as ‘leverage points’ in design for sustainable behaviour
Copyright @ 2012 Social Science Electronic PublishingTwo of Donella Meadows' 'leverage points' for intervening in systems (1999) seem particularly pertinent to design for sustainable behaviour, in the sense that designers may have the scope to implement them in (re-)designing everyday products and services. The 'rules of the system' -- interpreted here to refer to affordances and constraints -- and the structure of information flows both offer a range of opportunities for design interventions to in fluence behaviour change, and in this paper, some of the implications and possibilities are discussed with reference to parallel concepts from within design, HCI and relevant areas of psychology
Location Advantages, Governance Quality, Stock Market Development and Firm Characteristics as Antecedents of African M&As
This study explores firm- and country-specific antecedents of African M&As. We use one of the largest datasets to-date consisting of 1,490 unique African firms (11,183 firm-year observations) from 1996 to 2012. Our results suggest that improvements in time-varying country-level factors, including location advantages (market size, human capital and efficiency opportunities), national governance quality, and stock market development are associated with an increase in the volume of M&A activity. Consistent with the resource-curse paradox, high resource endowments are not associated with increased levels of M&A. In support of the management inefficiency but contrary to the traditional firm size hypotheses, African targets are generally characterised by declining stock returns and accounting profitability but are more likely to be larger firms; suggesting the presence of information asymmetry concerns in their selection. Notwithstanding, we find evidence of heterogeneity across countries with inconsistent support for established target prediction hypotheses. A model which combines firm- and country- specific factors better explains observed variations in African M&A activity
Teachers’ changing work and support needs from the perspectives of school leaders and newly qualified teachers in the Finnish context
Teachers operate amidst continuous societal changes that transform schools. In response, teachers must acquire wide-ranging professional competences to work in complex school situations while cooperating with numerous partners both within and outside the school. This study examines how teacher growth and the new demands of the teaching profession appear from the perspectives of school leaders and newly qualified teachers. The aim is to investigate in which professional competences new teachers require support at the beginning of their careers. After presenting various theoretical reflections, we analyse the empirical data of Finnish school leaders (N = 104) and new teachers (N = 145) using quantitative and qualitative methods. The results indicate that new teachers require support, for example, in order to provide holistic support for students’ learning and in working with partners, both within and outside the school community. The results provide important knowledge for the induction phase of teachers’ careers.Peer reviewe
Heroin versus cocaine: opposite choice as a function of context but not of drug history in the rat
Rationale
Previous studies have shown that rats trained to self-administer heroin and cocaine exhibit opposite preferences, as a function of setting, when tested in a choice paradigm. Rats tested at home prefer heroin to cocaine whereas rats tested outside the home prefer cocaine to heroin. Here we investigated whether drug history would influence subsequent drug preference in distinct settings. Based on a theoretical model of drug-setting interaction, we predicted that regardless of drug history rats would prefer heroin at home and cocaine outside the home.
Methods
Rats with double-lumen catheters were first trained to self-administer either heroin (25 μg/kg) or cocaine (400 μg/kg) for 12 consecutive sessions. Twenty-six rats were housed in the self-administration chambers (thus, they were tested at home) whereas 30 rats lived in distinct home cages and were transferred to self-administration chambers only for the self-administration session (thus, they were tested outside the home). The rats were then allowed to choose repeatedly between heroin and cocaine within the same session for 7 sessions.
Results
Regardless of the training drug, the rats tested outside the home preferred cocaine to heroin whereas the rats tested at home preferred heroin to cocaine. There was no correlation between drug preference and drug intake during the training phase.
Conclusion
Drug preferences were powerfully influenced by the setting but, quite surprisingly, not by drug history. This suggests that, under certain conditions, associative learning processes and drug-induced neuroplastic adaptations play a minor role in shaping individual preferences for one drug or the other
Understanding time-inconsistent heterogeneous preferences in economics and finance:A practice theory approach
Differential expression of Lp-PLA2 in obesity and type 2 diabetes and the influence of lipids
Aims/hypothesis
Lipoprotein-associated phospholipase A2 (Lp-PLA2) is a circulatory macrophage-derived factor that increases with obesity and leads to a higher risk of cardiovascular disease (CVD). Despite this, its role in adipose tissue and the adipocyte is unknown. Therefore, the aims of this study were to clarify the expression of Lp-PLA2 in relation to different adipose tissue depots and type 2 diabetes, and ascertain whether markers of obesity and type 2 diabetes correlate with circulating Lp-PLA2. A final aim was to evaluate the effect of cholesterol on cellular Lp-PLA2 in an in vitro adipocyte model.
Methods
Analysis of anthropometric and biochemical variables from a cohort of lean (age 44.4 ± 6.2 years; BMI 22.15 ± 1.8 kg/m2, n = 23), overweight (age 45.4 ± 12.3 years; BMI 26.99 ± 1.5 kg/m2, n = 24), obese (age 49.0 ± 9.1 years; BMI 33.74 ± 3.3 kg/m2, n = 32) and type 2 diabetic women (age 53.0 ± 6.13 years; BMI 35.08 ± 8.6 kg/m2, n = 35), as part of an ethically approved study. Gene and protein expression of PLA2 and its isoforms were assessed in adipose tissue samples, with serum analysis undertaken to assess circulating Lp-PLA2 and its association with cardiometabolic risk markers. A human adipocyte cell model, Chub-S7, was used to address the intracellular change in Lp-PLA2 in adipocytes.
Results
Lp-PLA2 and calcium-independent PLA2 (iPLA2) isoforms were altered by adiposity, as shown by microarray analysis (p < 0.05). Type 2 diabetes status was also observed to significantly alter gene and protein levels of Lp-PLA2 in abdominal subcutaneous (AbdSc) (p < 0.01), but not omental, adipose tissue. Furthermore, multivariate stepwise regression analysis of circulating Lp-PLA2 and metabolic markers revealed that the greatest predictor of Lp-PLA2 in non-diabetic individuals was LDL-cholesterol (p = 0.004). Additionally, in people with type 2 diabetes, oxidised LDL (oxLDL), triacylglycerols and HDL-cholesterol appeared important predictors, accounting for 59.7% of the variance (p < 0.001). Subsequent in vitro studies determined human adipocytes to be a source of Lp-PLA2, as confirmed by mRNA expression, protein levels and immunochemistry. Further in vitro experiments revealed that treatment with LDL-cholesterol or oxLDL resulted in significant upregulation of Lp-PLA2, while inhibition of Lp-PLA2 reduced oxLDL production by 19.8% (p < 0.05).
Conclusions/interpretation
Our study suggests adipose tissue and adipocytes are active sources of Lp-PLA2, with differential regulation by fat depot and metabolic state. Moreover, levels of circulating Lp-PLA2 appear to be influenced by unfavourable lipid profiles in type 2 diabetes, which may occur in part through regulation of LDL-cholesterol and oxLDL metabolism in adipocytes
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