All-optical transport and compression of ytterbium atoms into the surface of a solid immersion lens

We present an all-optical method to load 174Yb atoms into a single layer of an optical trap near the surface of a solid immersion lens which improves the numerical aperture of a microscope system. Atoms are transported to a region 20 um below the surface using a system comprised by three optical dipole traps. The "optical accordion" technique is used to create a condensate and compress the atoms to a width of 120 nm and a distance of 1.8 um away from the surface. Moreover, we are able to verify that after compression the condensate behaves as a two-dimensional quantum gas.Comment: 5 pages, 5 figure

An experimental route to spatiotemporal chaos in an extended 1D oscillators array

We report experimental evidence of the route to spatiotemporal chaos in a large 1D-array of hotspots in a thermoconvective system. Increasing the driving force, a stationary cellular pattern becomes unstable towards a mixed pattern of irregular clusters which consist of time-dependent localized patterns of variable spatiotemporal coherence. These irregular clusters coexist with the basic cellular pattern. The Fourier spectra corresponding to this synchronization transition reveals the weak coupling of a resonant triad. This pattern saturates with the formation of a unique domain of great spatiotemporal coherence. As we further increase the driving force, a supercritical bifurcation to a spatiotemporal beating regime takes place. The new pattern is characterized by the presence of two stationary clusters with a characteristic zig-zag geometry. The Fourier analysis reveals a stronger coupling and enables to find out that this beating phenomena is produced by the splitting of the fundamental spatiotemporal frequencies in a narrow band. Both secondary instabilities are phase-like synchronization transitions with global and absolute character. Far beyond this threshold, a new instability takes place when the system is not able to sustain the spatial frequency splitting, although the temporal beating remains inside these domains. These experimental results may support the understanding of other systems in nature undergoing similar clustering processes.Comment: 12 pages, 13 figure

High-Powered LED Assembly as Replacement for Conventional HBO Lamps in High Resolution, High Magnification Microscopy System

Through decades, fluorescence microscopy has relied on mercury vapor lamps as its main light source due to their high power, broad spectrum, and bright bands generated. The use of mercury vapor lamps has remained fundamentally associated with the required lighting equipment of research laboratories. However, as time progresses, mercury vapor lamps have been slowly replaced with technologies that offered longer lifetimes, less hazardous waste, and output light at similar intensities. LED technology has been actively used in biological research, but was limited by price, lower intensities, and stability. The recent development of LED technology has allowed for further understanding and implementation in the fluorescence microscopy area. We developed a system capable of fully replacing conventional mercury-based lamps with high-power LED technology suited to yield specific spectra, and sufficient power output to produce quality results. Moreover, this system provides a cost-effective, less hazardous alternative without the need for modifying conventional fluorescence microscopy system

Development of pituitary tumor-transforming gene (PTTG) transgenic mice for the treatment of ovarian cancer.

This dissertation is a hypothesis-driven research oriented study to determine the role of the pituitary-tumor transforming gene (PTTG) in ovarian cancer, specifically if it is involved in neoplastic transformation leading to tumorigenesis through oncogene activation and the involvement of tumor-suppressor gene, p53. Furthermore, generation of a useful ovarian cancer mouse model provides a platform technology to screen for ovarian cancer diagnosis and treatment options. This dissertation is divided into four chapters covering the etiology of ovarian cancer and a novel treatment strategy for ovarian cancer. The first chapter reviews the related literature encompassing the etiology of ovarian cancer, mouse models of ovarian cancer, the biological function of PTTG, the role of PTTG in cancer and diabetes, and mouse models using PTTG as a transgene. The second chapter studies the role of PTTG in tumorigenesis in vivo through the generation ofa PTTG transgenic (TgPTTG) mouse model observed at various ages, ranging from 4 to 10 months. The third chapter is a preliminary study investigating the signaling mechanisms affected by chemotherapy agent doxorubicin in combination with withaferin A in vitro and in vivo for the treatment of ovarian cancer. The fourth chapter is a discussion of the utility of ovarian cancer mouse models and the consequences of the lack of a working model

Normalizing Weak Boson Pair Production at the Large Hadron Collider

The production of two weak bosons at the Large Hadron Collider will be one of the most important sources of SM backgrounds for final states with multiple leptons. In this paper we consider several quantities that can help normalize the production of weak boson pairs. Ratios of inclusive cross-sections for production of two weak bosons and Drell-Yan are investigated and the corresponding theoretical errors are evaluated. The possibility of predicting the jet veto survival probability of VV production from Drell-Yan data is also considered. Overall, the theoretical errors on all quantities remain less than 5-20%. The dependence of these quantities on the center of mass energy of the proton-proton collision is also studied.Comment: 11 pages; added references, minor text revisions, version to appear in Phys. Rev.

Ovarian cancer mouse models: a summary of current models and their limitations

Development of mouse models representing human spontaneous ovarian cancer has been hampered by the lack of understanding of the etiology of this very complex disease. Mouse models representing the different types of ovarian cancer are needed to understand how epithelial ovarian cancer differs from granulosa cell tumors. Many different methods have been used to generate a viable genetic model with limited success. This review focuses on the methods of various investigators and the limitations of each model in establishing a reproducible and inheritable line to study this disease

Una nova eina per a l’estudi del paper i les filigranes. Anàlisi i desenvolupament d’una base de dades per a l’estudi del paper i de les filigranes: font per a l’elaboració de la història del paper a Espanya

Podeu consultar el document complet a: http://hdl.handle.net/2445/47384L’aspiració de trobar una eina que pugui ajudar a identifi car els papers atenent les seves característiques sorgeix a fi nal segle XVIII amb les primeres descripcions de les filigranes papereres i va prenent cos al segle XIX com a ciència auxiliar de la codicologia. Des de les últimes dècades del segle XX, les filigranes han anat adquirint un interès creixent entre els restauradors de document gràfi c —com una eina més per a la presa de decisions i per a la valoració del procés de restauració— i entre els documentalistes, historiadors, museòlegs i bibliòfils —per a la datació i autenticació de les obres— i, fins i tot, en investigacions policials i jurídiques per aclarir algun fet delictiu. No obstant això, durant aquests 150 anys, l’estudi del paper a través de les filigranes papereres a Espanya no ha experimentat cap avenç significatiu pel que fa als mètodes i procediments seguits per a l’obtenció i gestió de les dades. En l’àmbit europeu, encara que a partir dels anys 90 sorgeixen noves propostes d’estudi, aquestes limiten la investigació a l’anàlisi de la filigrana sense assolir una visió global del plec sortit de la forma

Magnetically-controlled impurities in quantum wires with strong Rashba coupling

We investigate the effect of strong spin-orbit interaction on the electronic transport through non-magnetic impurities in one-dimensional systems. When a perpendicular magnetic field is applied, the electron spin polarization becomes momentum-dependent and spin-flip scattering appears, to first order in the applied field, in addition to the usual potential scattering. We analyze a situation in which, by tuning the Fermi level and the Rashba coupling, the magnetic field can suppress the potential scattering. This mechanism should give rise to a significant negative magnetoresistance in the limit of large barriers.Comment: 4 pages, 2 figure