Udvikling af studerendes selvstændighed: Stilladsering i bachelorvejledning

I denne artikel undersøger vi hvordan studerendes selvstændighed kan opøves i forbindelse med opgaveskrivning. Vi tager afsæt i en teoretisk skelnen mellem selvstændighed i processen og i produktet og argumenterer for, at sidstnævnte kan og bør trænes undervejs i et opgaveforløb, så de studerende gradvist opnår øget sikkerhed i videnskabelige formidling. Datagrundlaget er en empirisk case, der indeholder dels en redegørelse for et konkret bacheloropgaveforløb på en samfundsvidenskabelig uddannelse, dels en analyse af forløbets resultater i form af skriftlige evalueringsdata, karakterdata og vejlederens egne observationer. Analysen viser, at vejledere kan fremme progression i studerendes selvstændighed gennem stilladsering, dvs. ved tidligt, gradvist og systematisk at indarbejde forskellige støttende aktiviteter som skriveøvelser, peer-feedback og kollektiv vejledning. Samlet skærper aktiviteterne de studerendes blik på videnskabelige genrekrav og afmonterer dermed meget af den usikkerhed, som de kan have omkring produktkravene til en selvstændig opgave. Resultatet er større mod på opgaveprocessen og højere kvalitet i de endelige produkter

The Association of a SNP Upstream of INSIG2 with Body Mass Index is Reproduced in Several but Not All Cohorts

A SNP upstream of the INSIG2 gene, rs7566605, was recently found to be associated with obesity as measured by body mass index (BMI) by Herbert and colleagues. The association between increased BMI and homozygosity for the minor allele was first observed in data from a genome-wide association scan of 86,604 SNPs in 923 related individuals from the Framingham Heart Study offspring cohort. The association was reproduced in four additional cohorts, but was not seen in a fifth cohort. To further assess the general reproducibility of this association, we genotyped rs7566605 in nine large cohorts from eight populations across multiple ethnicities (total n = 16,969). We tested this variant for association with BMI in each sample under a recessive model using family-based, population-based, and case-control designs. We observed a significant (p < 0.05) association in five cohorts but saw no association in three other cohorts. There was variability in the strength of association evidence across examination cycles in longitudinal data from unrelated individuals in the Framingham Heart Study Offspring cohort. A combined analysis revealed significant independent validation of this association in both unrelated (p = 0.046) and family-based (p = 0.004) samples. The estimated risk conferred by this allele is small, and could easily be masked by small sample size, population stratification, or other confounders. These validation studies suggest that the original association is less likely to be spurious, but the failure to observe an association in every data set suggests that the effect of SNP rs7566605 on BMI may be heterogeneous across population samples

Pilot testing of a sampling methodology for assessing seed attachment propensity and transport rate in a soil matrix carried on boot soles and bike tires

Land managers of natural areas are under pressure to balance demands for increased recreation access with protection of the natural resource. Unintended dispersal of seeds by visitors to natural areas has high potential for weedy plant invasions, with initial seed attachment an important step in the dispersal process. Although walking and mountain biking are popular nature-based recreation activities there are few studies quantifying propensity for seed attachment and transport rate on boot soles and none for bike tires. Attachment and transport rate can potentially be affected by a wide range of factors for which field testing can be time-consuming and expensive. We pilot tested a sampling methodology for measuring seed attachment and transport rate in a soil matrix carried on boot soles and bike tires traversing a known quantity and density of a seed analog (beads) over different distances and soil conditions. We found % attachment rate on boot soles was much lower overall than previously reported but that boot soles had a higher propensity for seed attachment than bike tires in almost all conditions. We believe our methodology offers a cost-effective option for researchers seeking to manipulate and test effects of different influencing factors on these two dispersal vectors

Abdominal aortic aneurysm is associated with a variant in low-density lipoprotein receptor-related protein 1

Abdominal aortic aneurysm (AAA) is a common cause of morbidity and mortality and has a significant heritability. We carried out a genome-wide association discovery study of 1866 patients with AAA and 5435 controls and replication of promising signals (lead SNP with a p value &lt; 1 × 10-5) in 2871 additional cases and 32,687 controls and performed further follow-up in 1491 AAA and 11,060 controls. In the discovery study, nine loci demonstrated association with AAA (p &lt; 1 × 10-5). In the replication sample, the lead SNP at one of these loci, rs1466535, located within intron 1 of low-density-lipoprotein receptor-related protein 1 (LRP1) demonstrated significant association (p = 0.0042). We confirmed the association of rs1466535 and AAA in our follow-up study (p = 0.035). In a combined analysis (6228 AAA and 49182 controls), rs1466535 had a consistent effect size and direction in all sample sets (combined p = 4.52 × 10-10, odds ratio 1.15 [1.10-1.21]). No associations were seen for either rs1466535 or the 12q13.3 locus in independent association studies of coronary artery disease, blood pressure, diabetes, or hyperlipidaemia, suggesting that this locus is specific to AAA. Gene-expression studies demonstrated a trend toward increased LRP1 expression for the rs1466535 CC genotype in arterial tissues; there was a significant (p = 0.029) 1.19-fold (1.04-1.36) increase in LRP1 expression in CC homozygotes compared to TT homozygotes in aortic adventitia. Functional studies demonstrated that rs1466535 might alter a SREBP-1 binding site and influence enhancer activity at the locus. In conclusion, this study has identified a biologically plausible genetic variant associated specifically with AAA, and we suggest that this variant has a possible functional role in LRP1 expression

Genome-wide association identifies nine common variants associated with fasting proinsulin levels and provides new insights into the pathophysiology of type 2 diabetes.

OBJECTIVE: Proinsulin is a precursor of mature insulin and C-peptide. Higher circulating proinsulin levels are associated with impaired β-cell function, raised glucose levels, insulin resistance, and type 2 diabetes (T2D). Studies of the insulin processing pathway could provide new insights about T2D pathophysiology. RESEARCH DESIGN AND METHODS: We have conducted a meta-analysis of genome-wide association tests of ∼2.5 million genotyped or imputed single nucleotide polymorphisms (SNPs) and fasting proinsulin levels in 10,701 nondiabetic adults of European ancestry, with follow-up of 23 loci in up to 16,378 individuals, using additive genetic models adjusted for age, sex, fasting insulin, and study-specific covariates. RESULTS: Nine SNPs at eight loci were associated with proinsulin levels (P < 5 × 10(-8)). Two loci (LARP6 and SGSM2) have not been previously related to metabolic traits, one (MADD) has been associated with fasting glucose, one (PCSK1) has been implicated in obesity, and four (TCF7L2, SLC30A8, VPS13C/C2CD4A/B, and ARAP1, formerly CENTD2) increase T2D risk. The proinsulin-raising allele of ARAP1 was associated with a lower fasting glucose (P = 1.7 × 10(-4)), improved β-cell function (P = 1.1 × 10(-5)), and lower risk of T2D (odds ratio 0.88; P = 7.8 × 10(-6)). Notably, PCSK1 encodes the protein prohormone convertase 1/3, the first enzyme in the insulin processing pathway. A genotype score composed of the nine proinsulin-raising alleles was not associated with coronary disease in two large case-control datasets. CONCLUSIONS: We have identified nine genetic variants associated with fasting proinsulin. Our findings illuminate the biology underlying glucose homeostasis and T2D development in humans and argue against a direct role of proinsulin in coronary artery disease pathogenesis

Dissecting the Shared Genetic Architecture of Suicide Attempt, Psychiatric Disorders, and Known Risk Factors

Background Suicide is a leading cause of death worldwide, and nonfatal suicide attempts, which occur far more frequently, are a major source of disability and social and economic burden. Both have substantial genetic etiology, which is partially shared and partially distinct from that of related psychiatric disorders. Methods We conducted a genome-wide association study (GWAS) of 29,782 suicide attempt (SA) cases and 519,961 controls in the International Suicide Genetics Consortium (ISGC). The GWAS of SA was conditioned on psychiatric disorders using GWAS summary statistics via multitrait-based conditional and joint analysis, to remove genetic effects on SA mediated by psychiatric disorders. We investigated the shared and divergent genetic architectures of SA, psychiatric disorders, and other known risk factors. Results Two loci reached genome-wide significance for SA: the major histocompatibility complex and an intergenic locus on chromosome 7, the latter of which remained associated with SA after conditioning on psychiatric disorders and replicated in an independent cohort from the Million Veteran Program. This locus has been implicated in risk-taking behavior, smoking, and insomnia. SA showed strong genetic correlation with psychiatric disorders, particularly major depression, and also with smoking, pain, risk-taking behavior, sleep disturbances, lower educational attainment, reproductive traits, lower socioeconomic status, and poorer general health. After conditioning on psychiatric disorders, the genetic correlations between SA and psychiatric disorders decreased, whereas those with nonpsychiatric traits remained largely unchanged. Conclusions Our results identify a risk locus that contributes more strongly to SA than other phenotypes and suggest a shared underlying biology between SA and known risk factors that is not mediated by psychiatric disorders.Peer reviewe

Sex-stratified Genome-wide Association Studies Including 270,000 Individuals Show Sexual Dimorphism in Genetic Loci for Anthropometric Traits

Peer reviewe

A genome-wide association search for type 2 diabetes genes in African Americans.

African Americans are disproportionately affected by type 2 diabetes (T2DM) yet few studies have examined T2DM using genome-wide association approaches in this ethnicity. The aim of this study was to identify genes associated with T2DM in the African American population. We performed a Genome Wide Association Study (GWAS) using the Affymetrix 6.0 array in 965 African-American cases with T2DM and end-stage renal disease (T2DM-ESRD) and 1029 population-based controls. The most significant SNPs (n = 550 independent loci) were genotyped in a replication cohort and 122 SNPs (n = 98 independent loci) were further tested through genotyping three additional validation cohorts followed by meta-analysis in all five cohorts totaling 3,132 cases and 3,317 controls. Twelve SNPs had evidence of association in the GWAS (P<0.0071), were directionally consistent in the Replication cohort and were associated with T2DM in subjects without nephropathy (P<0.05). Meta-analysis in all cases and controls revealed a single SNP reaching genome-wide significance (P<2.5×10(-8)). SNP rs7560163 (P = 7.0×10(-9), OR (95% CI) = 0.75 (0.67-0.84)) is located intergenically between RND3 and RBM43. Four additional loci (rs7542900, rs4659485, rs2722769 and rs7107217) were associated with T2DM (P<0.05) and reached more nominal levels of significance (P<2.5×10(-5)) in the overall analysis and may represent novel loci that contribute to T2DM. We have identified novel T2DM-susceptibility variants in the African-American population. Notably, T2DM risk was associated with the major allele and implies an interesting genetic architecture in this population. These results suggest that multiple loci underlie T2DM susceptibility in the African-American population and that these loci are distinct from those identified in other ethnic populations

Synthese, Funktionalisierung und Anwendung von magnetischen Eisenoxidnanopartikeln

Nanoskalierte Materialien haben aufgrund ihrer im Vergleich zum makroskopischen Festkörper besonderen Eigenschaften in den letzten Jahren in den unterschiedlichsten Bereichen zunehmend an Bedeutung gewonnen. Vor allem magnetische Nanopartikel finden vielseitige Anwendung, zu ihren möglichen Einsatzgebieten gehören z. B. magnetische Speichermedien und (heterogene) Katalyse, vor allem aber die Biomedizin, in der die Partikel als MRT-Kontrastmittel oder „Wirkstofftransporter“ dienen können. Für die meisten Anwendungsgebiete ist es erforderlich, Nanopartikel stets in der gewünschten Form und mit einer engen Größenverteilung zur Verfügung zu haben. Um dies mit einer hohen Reproduzierbarkeit zu erreichen, müssen zahlreiche Parameter der nasschemischen Herstellungsverfahren gesteuert und die Synthese dadurch gezielt beeinflusst werden können. Ein Teil dieser Arbeit widmet sich daher der Untersuchung des Wachstumsprozesses von Eisenoxid-basierten Nanopartikeln, um herauszufinden, auf welche Weise einzelne Faktoren wie Lösungsmittel, Temperatur, eingesetzte Ausgangssubstanzen und Art bzw. Verhältnis der Oberflächenliganden Einfluss auf Partikelgröße, -morphologie und -eigenschaften haben. In den nachfolgenden Kapiteln werden verschiedene Eisenoxidpartikelarten vorgestellt, die sich in ihrer Zusammensetzung und Morphologie unterscheiden. Die sphärischen, würfelförmigen und hohlen Partikel bestehen vollständig aus Eisenoxid, wohingegen die Kern-Schale-Partikel (Fe/FexO) sowie die Heterodimere (Ag@FexO, FePt@FexO) außer FexO noch eine weitere (metallische) Komponente aufweisen. Neben einer umfassenden Charakterisierung ihrer Eigenschaften werden Anwendungsmöglichkeiten der Eisenoxidpartikel aufgezeigt, wie beispielsweise die Bildung von Mesokristallen oder die Beladung mit Wirkstoffen. Durch Funktionalisierung mit einem hydrophilen Liganden wie Catechol-PEG oder Umhüllung mit Silica können die Partikel auch in polaren Lösungsmittel eingesetzt werden, was sie besonders attraktiv macht für biomedizinische Anwendungen. Due to their unique properties, nanoscaled materials have become more and more important within the last decade. Especially magnetic nanoparticles can be used in many different fields of application, such as magnetic data storage, (heterogeneous) catalysis or biomedicine, where the particles act as contrast agent in MRI or as drug delivery system. Most utilizations are only possible with highly mono¬disperse and uniform nanoparticles, what requires a precise control over the parameters of a wet-chemical synthesis. Therefore, in this work the influence of various reaction parameters, such as solvent, temperature, precursors, or amount of capping agent on size, shape, and properties of the resulting particles is investigated. In the following chapters several types of iron oxide-based nanoparticles are introduced, which differ in constitution and morphology. The spherical, cubic and hollow particles consist of iron oxide completely, whereas the core-shell particles (Fe/FexO) and heterodimers (Ag@FexO, FePt@FexO) contain an additional (metal) component. Besides the thoroughly characterization of the properties possible utilizations of the particles are presented, such as building up mesocrystals or drug load. By functionalizing the particles with hydrophilic ligands like catechol-PEG or by coating with silica shell they can be used in hydrophilic solvents as well, which makes them very attractive for biomedical applications

Should there exist secondary markets for executive stock options?

This paper investigates the potential disadvantages of the secondary markets for executive stock options (ESOs). The benefits of such markets are evident, but they might also have negative effects for shareholders. Executives might, for example, use inside information to time their ESO selling. We investigate two personal motives of managers that can be assumed to affect their optimal selling decision, that is, managers' personal portfolio management issues and the use of inside information. We explore these motives by analyzing unique data from Finland, where there are secondary markets for ESOs. The results of the study support the traditional portfolio diversification hypothesis according to which managers tend to sell their ESOs when holding an ESO is equivalent to holding the underlying stock; that is, in such a case a manager's wealth is closely tied to the stock price of the firm. With respect to the use of inside information the results indicate that ESO selling activity is not related to future stock price behaviour, suggesting that managers do not use inside information to determine the selling time of their ESOs. These results imply that the existence of secondary markets for ESOs does not weaken the usefulness of ESOs as the management compensation, although the benefits of such markets are evident. Copyright The Authors Journal compilation (c) 2006 AFAANZ.