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Search Results: 1 - 10 of 445319 matches for " David M. Cairns "
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Beyond the myths about the natural and social sciences: A sociological view
David Cairns
Sociologia, Problemas e Práticas , 2010,
Migration, Mobility, and Borders: Issues of Theory and Policy, IKO-Verlag fur Interkulturelle Kommunikation
David Cairns
Análise Social , 2006,
A New Youth? Young People, Generations and Family Life
David Cairns
Análise Social , 2006,
Evaluating Southern Appalachian Forest Dynamics without Eastern Hemlock: Consequences of Herbivory by the Hemlock Woolly Adelgid  [PDF]
Andrew G. Birt, Yu Zeng, Maria D. Tchakerian, Robert N. Coulson, Charles W. Lafon, David M. Cairns, John Waldron, Weimin Xi, Szu-Hung Chen, Douglas A. Street
Open Journal of Forestry (OJF) , 2014, DOI: 10.4236/ojf.2014.42014

Eastern hemlock (Tsuga canadensis Carriére) and the Carolina hemlock (Tsuga caroliniana Engelmann) are ecologically important tree species in eastern North America forests that are currently threatened by the hemlock woolly adelgid (HWA, Adelges tsugae Annand, Hemiptera: Adelgidae). HWA has spread rapidly from its original introduction site into new areas. Once present, HWA kills its hosts over a period of 4 to 10 years leading to a phenomenon that is known scientifically and colloquially as hemlock decline. To date, quarantine, chemical management, and biocontrol efforts have failed to curb the spread of the HWA. As such, forest management efforts are now being redirected towards developing an understanding of the effects of hemlock removal on vegetation dynamics, changes in forest composition, and changes in ecosystem function. In this study, we parameterize a spatially explicit landscape simulation model LANDIS II for a specific forested region of the southern Appalachians. Parameterization involves defining the life-history attributes of 37 tree species occupying 11 ecological zones and is based on knowledge of: current vegetation composition data, recent historic management and fire regimes, and life-history traits of each species. The parameterized model is used to explore a simple scenario of catastrophic hemlock mortality likely to occur as a result of HWA herbivory. Our results emphasize that hemlock is an important foundation species. When hemlock is removed from the system, forest composition changes considerably with a greater presence of shade intolerant pine and oak species. Additionally, hemlock removal leads to a period of transient, relatively unstable

Social Capital and Student Achievement: Exploring the Influence of Social Relationships on School Success in Norway and Romania  [PDF]
Lihong Huang, Diana D?mean, David Cairns
Creative Education (CE) , 2015, DOI: 10.4236/ce.2015.615166
Abstract: This paper investigates student social relationships in secondary schools and its relationship with student achievement in Norway and Romania. Using data from national youth surveys (“Young in Norway 2010” for Norway and “School Success Profile Survey 2010” for Romania), we explore the concept and measurement of social capital in the school context by applying factor analysis. The paper also tests an analytical model that links student home background, student social capital and student academic achievement, using a structural equation modelling technique (LISREL). Control variables in the analysis are student gender and ethnicity. Testing the analytical model with the two datasets respectively, the results show that student social capital, generated from student social relations with parents, teachers and peers, has a significant influence on student achievement in both countries. Analysis also confirms differences between the two countries in respect to the effect of home background variables and social capital on achievement.
The relationship between predicted peptide–MHC class II affinity and T-cell activation in a HLA-DRβ1*0401 transgenic mouse model
Jonathan A Hill, Dequn Wang, Anthony M Jevnikar, Ewa Cairns, David A Bell
Arthritis Research & Therapy , 2002, DOI: 10.1186/ar605
Abstract: Rheumatoid arthritis (RA) is an autoimmune disease that is genetically associated with MHC class II molecules that contain the shared epitope. This shared epitope is a conserved amino acid motif (QK/RRAA) found within the third hypervariable region of the DRβ chains of DRB1*0101, DRB1*0404, and DRB1*0401. Notably, HLA-DR molecules not associated with RA (e.g. DRB1*0402) contain oppositely charged amino acids at some of these positions (DERAA). Because this shared epitope is found within the peptide-binding groove of these MHC class II molecules, it may confer the ability to selectively bind arthritogenic peptide sequences for presentation to auto-reactive T cells.The participation of CD4+ T cells in initiating and perpetuating the inflammatory response seen in RA has been well documented [1]. The protein/peptide targets recognized by these T cells, however, have not been conclusively identified. Studies in mouse models have shown that immunization with joint derived proteins such as type II collagen (CII) and the human proteoglycan aggrecan (hAG) can induce an RA-like disease that is MHC class II restricted [2-4]. Advances in determining human MHC class II restricted T-cell epitopes from CII have been made using DRβ1*0401 (DR4) transgenic mice [5-8]. Using overlapping peptide sequences, a single dominant epitope has been characterized that has a relatively high affinity for DR4 [7,8]. Although overlapping peptide sequences have conventionally been used to determine T-cell epitopes, quantitative MHC binding motifs that predict peptide–DRB1*0401 affinity have proven to be a valuable tool [6,9,10]. These predictive models have shown that specific amino acid side-chains within a bound peptide contribute to DR4 binding affinity, depending on their location within the binding groove [11-13]. Models such as these have defined a number of DR4 restricted T-cell epitopes, and may aid in determining an arthritogenic peptide.The foregoing may also help to identify molecular mim
Geography, private costs and uptake of screening for abdominal aortic aneurysm in a remote rural area
Sandra M Lindsay, John L Duncan, John Cairns, David J Godden
BMC Public Health , 2006, DOI: 10.1186/1471-2458-6-80
Abstract: Men aged 65–74 (n = 9323) were invited to attend screening at 51 locations in 50 settlements. Effects of geography, deprivation and age on uptake were examined. Among 8,355 attendees, 8,292 completed a questionnaire detailing mode of travel and costs incurred, time travelled, whether accompanied, whether dependants were cared for, and what they would have been doing if not attending screening, thus allowing private costs to be calculated. Health provider (NHS) costs were also determined. Data were analysed by deprivation categories, using the Scottish Indices of Deprivation (2003), and by settlement type ranging from urban to very remote rural.Uptake of screening was high in all settlement types (mean 89.6%, range 87.4 – 92.6%). Non-attendees were more deprived in terms of income, employment, education and health but there was no significant difference between non-attendees and attendees in terms of geographical access to services. Age was similar in both groups. The highest private costs (median £7.29 per man) and NHS screening costs (£18.27 per man invited) were observed in very remote rural areas. Corresponding values for all subjects were: private cost £4.34 and NHS cost £15.72 per man invited.Uptake of screening for abdominal aortic aneurysm in this remote and rural setting was high in comparison with previous studies, and this applied across all settlement types. Geographical location did not affect uptake, most likely due to the outreach approach adopted. Private and NHS costs were highest in very remote settings but still compared favourably with other published studies.Screening for abdominal aortic aneurysm (AAA) has been carried out in the UK for over twenty years. The effectiveness of this intervention in detection and management of abdominal aortic aneurysms has been the subject of debate in the literature [1-5]. However, recent evidence suggests that screening for AAA can be clinically and cost effective in reducing aneurysm mortality among men aged 65
Interplay of Nkx3.2, Sox9 and Pax3 Regulates Chondrogenic Differentiation of Muscle Progenitor Cells
Dana M. Cairns, Renjing Liu, Manpreet Sen, James P. Canner, Aaron Schindeler, David G. Little, Li Zeng
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0039642
Abstract: Muscle satellite cells make up a stem cell population that is capable of differentiating into myocytes and contributing to muscle regeneration upon injury. In this work we investigate the mechanism by which these muscle progenitor cells adopt an alternative cell fate, the cartilage fate. We show that chick muscle satellite cells that normally would undergo myogenesis can be converted to express cartilage matrix proteins in vitro when cultured in chondrogenic medium containing TGF?3 or BMP2. In the meantime, the myogenic program is repressed, suggesting that muscle satellite cells have undergone chondrogenic differentiation. Furthermore, ectopic expression of the myogenic factor Pax3 prevents chondrogenesis in these cells, while chondrogenic factors Nkx3.2 and Sox9 act downstream of TGF? or BMP2 to promote this cell fate transition. We found that Nkx3.2 and Sox9 repress the activity of the Pax3 promoter and that Nkx3.2 acts as a transcriptional repressor in this process. Importantly, a reverse function mutant of Nkx3.2 blocks the ability of Sox9 to both inhibit myogenesis and induce chondrogenesis, suggesting that Nkx3.2 is required for Sox9 to promote chondrogenic differentiation in satellite cells. Finally, we found that in an in vivo mouse model of fracture healing where muscle progenitor cells were lineage-traced, Nkx3.2 and Sox9 are significantly upregulated while Pax3 is significantly downregulated in the muscle progenitor cells that give rise to chondrocytes during fracture repair. Thus our in vitro and in vivo analyses suggest that the balance of Pax3, Nkx3.2 and Sox9 may act as a molecular switch during the chondrogenic differentiation of muscle progenitor cells, which may be important for fracture healing.
Administration of Heme Arginate Ameliorates Murine Type 2 Diabetes Independently of Heme Oxygenase Activity
Abhijeet K. Choudhary, Jillian Rennie, Carolynn Cairns, Gary Borthwick, Jeremy Hughes, Nicholas M. Morton, David Kluth, Bryan R. Conway
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0078209
Abstract: Amelioration of rodent type 2 diabetes by hemin has been linked to increased heme oxygenase (HO) activity, however alternative mechanisms have recently been proposed for its anti-diabetic effect. We sought to determine the anti-diabetic efficacy of heme arginate (HA), a clinically licensed preparation of heme, and whether its predominant mode of action is via increased HO activity. Intravenous administration of HA reduced hyperglycemia in diabetic (db/db) mice. Co-administration of the HO inhibitor stannous (IV) mesoporphyrin IX dichloride (SM) resulted unexpectedly in a further improvement in glycaemic control despite restoring HO activity to baseline levels. The anti-diabetic effects of HA±SM were associated with increased adiposity, increased serum adiponectin levels, reduced adipose tissue and islet inflammation and preservation of islet β-cell function. HO activity independent effects of HA on adipogenesis and β-cell inflammation were further confirmed in cell culture models using the 3T3-L1 pre-adipocyte and MIN6 β-cell lines, respectively. In conclusion, our work demonstrates that the heme component of HA ameliorates experimental type 2 diabetes by promoting metabolically favourable adipogenesis and preserving islet β-cell function, but this is not mediated via increased HO activity.
Iterative atmospheric correction scheme and the polarization color of alpine snow
M. Ottaviani,>B. Cairns
Atti della Accademia Peloritana dei Pericolanti : Classe di Scienze Fisiche, Matematiche e Naturali , 2011, DOI: 10.1478/c1v89s1p073
Abstract: Proper characterization of the Earth’s surface is crucial to remote sensing, both to map geomorphological features and because subtracting this signal is essential during retrievals of the atmospheric constituents located between the surface and the sensor. Current operational algorithms model the surface total reflectance through a weighted linear combination of geometry-dependent kernels, each devised to describe a particular scattering mechanism. The information content of intensity-only measurements is overwhelmed by instruments with polarization capabilities. Because of their remarkable lack of spectral contrast, the polarized reflectances of land surfaces in the shortwave infrared spectral region (where atmospheric scattering is minimal) can be used to model the surface at shorter wavelengths, where aerosol retrievals are performed.
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