A versatile system for the study of light-matter interactions at the level of individual particles

In this thesis, a single-atom trap in a "Maltese cross'' geometry (MCG) was designed, built up and characterized. A MCG atom trap uses four in-vacuum lenses to achieve four-directional high-numerical-aperture optical coupling to single trapped atoms and small atomic arrays. Here, we describe the theoretical background, the design, and the optical methods used for trapping and cooling atoms in a MCG geometry optimized for high coupling efficiency. We also characterize the resulting properties of the trap and trapped atoms. For this propose we measure occupancy, loading rate, lifetime, temperature, fluorescence anti-bunching and trap frequencies using current best practices. We also report another use of the optical control and coupling offered by the MCG: we use the two on-trap-axis lenses to produce a 1D optical lattice, the sites of which are stochastically filled and emptied by the trap loading process. The two off-trap-axis lenses are used for imaging and single-mode collection. Correlations of single-mode and imaging fluorescence signals are then used to map the single-mode collection efficiency. We observe trap characteristics comparable to what has been reported for single-atom traps with one- or two-lens optical systems. This shows that four-direction high-NA coupling can be achieved with little reduction in trap performance. Finally, we conclude with the near-future plans of the experiment.Postprint (published version

Using student feedback about the learning environment as a starting point for co-construction

The context in which learning takes place, or learning environment, is pivotal to a positive learning experience for students. Although numerous studies have established strong links between a positive learning environment and a range of student outcomes, far less research has examined how teachers might establish such an environment. Amidst growing acknowledgment that opportunities for the co-construction of learning and assessment design could provide a means of developing a more positive learning environment, this case study examined one such journey. Using a case study approach, we argue that student feedback involving a learning environment survey provides a valuable starting point for including students in co-construction and classroom improvement. Our findings indicate that teachers can improve the learning environment by involving students in meaningful co-construction through open tasks

Making the Right Moves

The structure of the nucleotide-free F1-ATPase from a thermoalkaliphilic bacterium presented in this issue of Structure (Stocker et al., 2007) reveals the structural interactions that prevent the enzyme from operating naturally in the hydrolytic direction. The data provide new insights into the mechanism of the FoF1-ATP synthase

Exploring the role of fallopian ciliated cells in the pathogenesis of high-grade serous ovarian cancer

High-grade serous epithelial ovarian cancer (HGSOC) is the fifth leading cause of cancer death in women and the first among gynecological malignancies. Despite an initial response to standard chemotherapy, most HGSOC patients relapse. To improve treatment options, we must continue investigating tumor biology. Tumor characteristics (e.g., risk factors and epidemiology) are valuable clues to accomplish this task. The two most frequent risk factors for HGSOC are the lifetime number of ovulations, which is associated with increased oxidative stress in the pelvic area caused by ovulation fluid, and a positive family history due to genetic factors. In the attempt to identify novel genetic factors (i.e., genes) associated with HGSOC, we observed that several genes in linkage with HGSOC are expressed in the ciliated cells of the fallopian tube. This finding made us hypothesize that ciliated cells, despite not being the cell of origin for HGSOC, may take part in HGSOC tumor initiation. Specifically, malfunction of the ciliary beat impairs the laminar fluid flow above the fallopian tube epithelia, thus likely reducing the clearance of oxidative stress caused by follicular fluid. Herein, we review the up-to-date findings dealing with HGSOC predisposition with the hypothesis that fallopian ciliated cells take part in HGSOC onset. Finally, we review the up-to-date literature concerning genes that are located in genomic loci associated with epithelial ovarian cancer (EOC) predisposition that are expressed by the fallopian ciliated cells

Assessing senescence patterns in populations of large mammals

Theoretical models such as those of Gompertz and Weibull are commonly used to study senescence in survival for humans and laboratory or captive animals. For wild populations of vertebrates, senescence in survival has more commonly been assessed by fitting simple linear or quadratic relationships between survival and age. By using appropriate constraints on survival parameters in Capture-Mark-Recapture (CMR) models, we propose a first analysis of the suitability of the Gompertz and the two-parameter Weibull models for describing aging-related mortality in free-ranging populations of ungulates. We first show how to handle the Gompertz and the two-parameter Weibull models in the context of CMR analyses. Then we perform a comparative analysis of senescence patterns in both sexes of two ungulate species highly contrasted according to the intensity of sexual selection. Our analyses provide support to the Gompertz model for describing senescence patterns in ungulates. Evolutionary implications of our results are discusse

The effect of radio-collar weight on survival of migratory caribou

Radio transmitters are widely used in wildlife management; therefore, it is essential to assess any effects that they may have on animal survival. We compared the survival of 269 randomly selected adult migratory caribou (Rangifer tarandus) fitted with either light very high frequency or heavy Argos satellite collars during the same period. Heavy collars reduced annual survival of caribou in a declining population with generally poor body condition by about 18%. Accurate estimates of survival are crucial for management decisions and possible effects of collars should be considered when calculating estimates

Estudio experimental y modelado de la deshidratación topotáctica del ácido amino-undecanoico dihidratado en estado sólido

El presente trabajo incluye el estudio experimental de una transformación de fase de interés práctico y al mismo tiempo susceptible de tratamiento teórico: la deshidratación de un compuesto orgánico, el ácido a,w-aminoundecanoico (11AUD.2H2O). 11AUD.2H2O es el monómero a partir del cual, por polimerización en estado sólido, se obtiene el polímero altamente orientado conocido como Nylon-11. El monómero a su vez debe deshidratarse previamente, y las propiedades del material polimérico dependerán de las características de las transformaciones en fase sólida involucradas.Facultad de Ciencias Exacta