4,733 research outputs found
Methodological challenges in pregnancy pharmacoepidemiology : the case of antiseizure medication and offspring neurodevelopment
This thesis is driven by the overarching aim of elucidating methodological challenges
inherent in pharmacoepidemiology during pregnancy, with a particular focus on
antiseizure medications. In Study I, a substantial surge in antiseizure medication use in
the United Kingdom is observed, notably linked to increases in psychiatric indications.
This shift in the medication landscape raises questions about the predominant
contributors to this rise and underscores the necessity of understanding evolving
patterns in drug utilization during pregnancy. In Study II, a large-scale examination of
associations between specific antiseizure medications and neurodevelopmental
conditions across Sweden and the United Kingdom emphasizes the importance of
considering drug classes and shared confounders, providing valuable insights into the
possible causal effect of these drugs.
Study III explores the intricate interplay between epilepsy and psychiatric conditions,
unveiling a heightened risk of neurodevelopmental conditions in individuals diagnosed
with epilepsy. These findings shed light on the complex within-individual links between
these conditions, potentially explaining the observed higher likelihood of
neurodevelopmental diagnoses in children of women using antiseizure medications in
pregnancy. In Study IV, a critical evaluation of drug safety studies warns against
indication-based sampling, advocating for comprehensive regression adjustments to
mitigate biases. Finally, Study V introduces the marginalized between-within model, a
novel approach to derive absolute measures of occurrence in sibling analysis, enhancing
the interpretability of findings.
This thesis, collectively, calls for a concerted effort to improve the methodology of
pharmacoepidemiology during pregnancy, fostering a more nuanced understanding of
medication risks, and ultimately enhancing maternal and fetal health outcomes
Hyperk\"ahler Arnold Conjecture and its Generalizations
We generalize and refine the hyperk\"ahler Arnold conjecture, which was
originally established, in the non-degenerate case, for three-dimensional time
by Hohloch, Noetzel and Salamon by means of hyperk\"ahler Floer theory. In
particular, we prove the conjecture in the case where the time manifold is a
multidimensional torus and also establish the degenerate version of the
conjecture. Our method relies on Morse theory for generating functions and a
finite-dimensional reduction along the lines of the Conley-Zehnder proof of the
Arnold conjecture for the torus.Comment: 13 page
Gain-assisted slow to superluminal group velocity manipulation in nano-waveguides
We study the energy propagation in subwavelength waveguides and demonstrate
that the mechanism of material gain, previously suggested for loss
compensation, is also a powerful tool to manipulate dispersion and propagation
characteristics of electromagnetic pulses at the nanoscale. We show
theoretically that the group velocity in lossy nano-waveguides can be
controlled from slow to superluminal values by the material gain and waveguide
geometry and develop an analytical description of the relevant physics. We
utilize the developed formalism to show that gain-assisted dispersion
management can be used to control the transition between ``photonic-funnel''
and ``photonic-compressor'' regimes in tapered nano-waveguides. The phenomenon
of strong modulation of group velocity in subwavelength structures can be
realized in waveguides with different geometries, and is present for both
volume and surface-modes.Comment: Some changes in the abstract and Fig.1. No results affecte
Identifying functional relationships within sets of co-expressed genes by combining upstream regulatory motif analysis and gene expression information
Existing clustering approaches for microarray data do not adequately differentiate between subsets of co-expressed genes. We devised a novel approach that integrates expression and sequence data in order to generate functionally coherent and biologically meaningful subclusters of genes. Specifically, the approach clusters co-expressed genes on the basis of similar content and distributions of predicted statistically significant sequence motifs in their upstream regions
Facilitating Organizational Adoption of Sensor-Based Systems: Espoused Beliefs, Shared Assumptions and Perceived Values
The advent of sensor-based systems with their ability to collect, transmit and process context-aware data creates new opportunities for service delivery. We know from earlier research that there may be barriers to the adoption of new information technology (IT) within an organization. Sensor-based systems, with unprecedented potential for monitoring of products, people and processes are an interesting mix of potential and risk. Through the lens of organizational culture theory, we examine the question: Given the ambiguity and complexity of sensor-based systems, how does organizational culture influence perceptions of system value and purpose, and which factors determine the susceptibility of adoption among individual workers and teams? Our results suggest that the adoption of sensor-based systems is facilitated by 1) a basic comprehension of the system, its functionality, purpose and limitations; 2) a shared view of stakeholdersâ roles and responsibilities, and 3) a pronounced and tangible vision for value creation
Boundary hopping and the mobility edge in the Anderson model in three dimensions
It is shown, using high-precision numerical simulations, that the mobility
edge of the 3d Anderson model depends on the boundary hopping term t in the
infinite size limit. The critical exponent is independent of it. The
renormalized localization length at the critical point is also found to depend
on t but not on the distribution of on-site energies for box and Lorentzian
distributions. Implications of results for the description of the transition in
terms of a local order-parameter are discussed
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