Spatial and energetic mode dynamics of cold atomic systems

In this thesis we relate the formal description of various cold atomic systems in the energy eigenbasis, to the observable spatial mode dynamics. Herein the `spatial mode dynamics' refers to the direction of photon emission following the spontaneous emission of an excited fermion in the presence of a same species and spin ideal anisotropic Fermi sea in its internal ground state. Due to the Pauli principle, the presence of the ground state Fermi sea renders the phase space, anisotropic and only partially accessible, thereby a ecting the direction of photon emission following spontaneous emission. The spatial and energetic mode dynamics also refers to the quantum `tunneling' interaction between localised spatial modes, synonymous with double well type potentials. Here we relate the dynamics of the wavefunction in both the energetic and spatial representations. Using this approach we approximate the relationship between the spatial and energetic representations of a wavefunction spanning three spatial and energetic modes. This is extended to a process known as Spatial Adiabatic Passage, which is a technique to transport matter waves between localised spatial modes. This approach allows us to interpret the transport of matter waves as a signature of a geometric phase acquired by the one of the internal energy eigenstates of the system during the cyclical evolution. We further show that this geometric phase may be used to create spatial mode qubit and qutrit states.

A study of the regulation of Trib family members expression in normal and malignant haematopoiesis

The Tribbles family of genes consist of three members; TRIB1, TRIB2 and TRIB3. Trib1 and Trib2 have been identified as oncogenes that can induce AML in mice. However little is known about how the expressions of the Tribbles family genes are controlled in the cell during haematopoiesis or leukaemogenesis. To investigate the Tribbles genes in leukaemia a bioinformatics approach was used. TRIB2 expression was found to be elevated in T-ALL and ALL with t(1;19). TRIB1 was found not to be significantly elevated in any leukaemic subtypes. Analyses of the TRIB1 and TRIB2 gene signatures in both leukaemic and normal haematopoietic cells identified pathways and transcription factors associated with these signatures. Pathways enriched for the TRIB1 signature included TLR signalling pathways and NF-κB pathways. Transcription factors enriched for this signature include C/EBP and SRF. Enriched for the TRIB2 signature includes T cell signalling pathways and Notch signalling pathways. Transcription factors enriched for this signature include E2F and ETS. Further investigation in vitro confirmed the finding that E2F1 was as a potential regulator of TRIB2 expression. E2F1 is able to directly bind to the TRIB2 promoter region and induce TRIB2 expression. C/EBPα p42 was found to inhibit E2F1 and the p30 isoform was found to cooperate with E2F1 induced activation of the TRIB2 promoter. Indicating the potential presence of a regulatory loop involved in the regulation of the TRIB2 gene. In conclusion we have investigated the Tribbles gene signatures in both normal haematopoietic and leukaemic cells. This has led to the identification of a number of pathways and transcription factors associated with these genes. We have also identified a family of transcription factors directly responsible for the regulation of TRIB2 expression. This regulatory pathway has the potential to be targeted in the treatment of leukaemia with a high TRIB2 signature.

Ireland's knowledge economy policy: beliefs, drivers and prospects

This dissertation critically examines Ireland’s knowledge economy policy, the country’s basis for economic recovery and growth, to enhance future policy decisions and debate. Much has been written internationally on the ‘knowledge economy’ with its emergence closely related to globalisation and technological progression in the 1990s. Since the late 1990s, Irish policy-makers have been firmly committed to positioning Ireland as a leading knowledge economy. Transforming the country’s competitive base to a knowledge economy is pivotal, directly shaping the course of Ireland’s economy and society. Given Ireland’s current economic crisis, limited resources, global competition from leaders in science and technology and growing challenges from emerging economies, a systematic study of Ireland’s major competitive policy is imperative. Above all, this study explores the processes behind the policy and the multiple actors from different institutions who follow and seek to influence decisions. The advocacy coalition framework is used to identify the advocacy coalition operating in the knowledge economy policy subsystem. The theoretical insights of this framework are also combined with other public policy approaches, providing complementary insights into the policy process. The research is framed around three elements - the beliefs underpinning the policy; who is driving the policy; and the prospects of the policy. Primary information is collected by way of semi-structured in-depth interviews with 49 Irish elites (politicians, senior bureaucrats, academics and business leaders) involved in the formation and implementation of the policy. This study finds that a strong advocacy coalition has formed in this policy subsystem whose members are collectively driving the policy. Both exogenous and endogenous forces help frame a common perception of the problems the policy addresses and the solutions it offers. Evidence suggests that this policy is a sustainable option for Ireland’s economic future and the study concludes with policy recommendations for advancing Ireland’s knowledge economy.

Highly sensitive surface enhanced Raman scattering (SERS) detection platforms formed by large area self-assembled Au nanorod arrays

This thesis explores a new method to fabricate SERS detection platforms formed by large area self-assembled Au nanorod arrays. For the fabrication of these new SERS platforms a new droplet deposition method for the self-assembly of Au nanorods was developed. The method, based in the controlled evaporation of organic suspensions of Au nanorods, was used for the fabrication of horizontal and vertical arrays of Au nanorods over large areas (100μm2). The fabricated nanorods arrays showed a high degree of order measured by SEM and optical microscopy over mm2 areas, but unfortunately they detached from the support when immersed in any analyte solutions. In order to improve adhesion of arrays to the support and clean off residual organic matter, we introduced an additional stamping process. The stamping process allows the immobilization of the arrays on different flexible and rigid substrates, whose feasibility as SERS platforms were tested satisfactory with the model molecule 4ABT. Following the feasibility study, the substrates were used for the detection of the food contaminant Crystal Violet and the drug analogue Benzocaine as examples of recognition of health menaces in real field applications.

Eleanor Roosevelt: supporting Zion, denying Palestine

Eleanor Roosevelt, as a renowned humanitarian, portrayed an inconsistency by supporting Zionist ambitions for a national homeland in Palestine while simultaneously ignoring the rights of the indigenous Palestinians. Because of this dichotomy, this dissertation explores her attitudes, her disposition and her position in light of the conflict in the region. It conveys how her particular character traits interplayed with the cultural influences prevalent in mid-century America and encouraged her empathy with the plight of European Jews after the Holocaust. As she evolved politically, initially under the tutelage of Franklin Roosevelt and latterly as a UN delegate, she outgrew the anti-Semitism of the period to become a committed Zionist. Judging the Palestinians as ‘primitives’ incapable of self-government and heartened by Jewish development, she supported the partition of Palestine in November 1947. After the 1948 Arab-Israeli war the 800,000 Palestinian refugees encamped in neighbouring Arab states threatened to destabilise the region. Her solution was to discourage repatriation and to re-settle them in Iraq – a plan that directly contravened the principles of the December 1948 Universal Declaration of Human Rights proclaimed by the UN committee she had chaired. No detailed work has been conducted on these aspects of Eleanor Roosevelt’s life; this dissertation reveals a complex person rather than a model of ‘humanitarianism’, and one whose activities cannot be so simply categorised. In the eight chapters that follow, her own thoughts are disclosed through her ‘My Day’ newspaper column, through letters to friends and to members of the public that petitioned her, through a scrutiny of her articles, books and autobiography. This information was attained as a result of archival research in the US and in The Netherlands and was considered against an extensive range of secondary literature. During the Cold War, to offset Soviet incursion, Eleanor Roosevelt promoted Jewish usurpation of Palestinian lands with equanimity in order that an industrious Western-style democracy would bring stability to the region. These events facilitated the exposure of a latent Orientalism and an imperialistic lien that fostered paternalism in a woman new to the nuances of international diplomacy.

Bunching-induced optical nonlinearity and instability in cold atoms [Invited].

We report a new nonlinear optical process that occurs in a cloud of cold atoms at low-light-levels when the incident optical fields simultaneously polarize, cool, and spatially-organize the atoms. We observe an extremely large effective fifth-order nonlinear susceptibility of χ(⁵) = 7.6 × 10⁻¹⁵ (m/V)⁴, which results in efficient Bragg scattering via six-wave mixing, slow group velocities (∼ c/10⁵), and enhanced atomic coherence times (> 100 μs). In addition, this process is particularly sensitive to the atomic temperatures, and provides a new tool for in-situ monitoring of the atomic momentum distribution in an optical lattice. For sufficiently large light-matter couplings, we observe an optical instability for intensities as low as ∼ 1 mW/cm² in which new, intense beams of light are generated and result in the formation of controllable transverse optical patterns.

Design and Emergence in the Making of American Grand Strategy

The main research question of this thesis is how do grand strategies form. Grand strategy is defined as a state's coherent and consistent pattern of behavior over a long period of time in search of an overarching goal. The political science literature usually explains the formation of grand strategies by using a planning (or design) model. In this dissertation, I use primary sources, interviews with former government officials, and historical scholarship to show that the formation of grand strategy is better understood using a model of emergent learning imported from the business world. My two case studies examine the formation of American grand strategy during the Cold War and the post-Cold War eras. The dissertation concludes that in both these strategic eras the dominating grand strategies were formed primarily by emergent learning rather than flowing from advanced designs.

Facilitators and barriers to hypertension self-management in urban African Americans: perspectives of patients and family members.

INTRODUCTION: We aimed to inform the design of behavioral interventions by identifying patients' and their family members' perceived facilitators and barriers to hypertension self-management. MATERIALS AND METHODS: We conducted focus groups of African American patients with hypertension and their family members to elicit their views about factors influencing patients' hypertension self-management. We recruited African American patients with hypertension (n = 18) and their family members (n = 12) from an urban, community-based clinical practice in Baltimore, Maryland. We conducted four separate 90-minute focus groups among patients with controlled (one group) and uncontrolled (one group) hypertension, as well as their family members (two groups). Trained moderators used open-ended questions to assess participants' perceptions regarding patient, family, clinic, and community-level factors influencing patients' effective hypertension self-management. RESULTS: Patient participants identified several facilitators (including family members' support and positive relationships with doctors) and barriers (including competing health priorities, lack of knowledge about hypertension, and poor access to community resources) that influence their hypertension self-management. Family members also identified several facilitators (including their participation in patients' doctor's visits and discussions with patients' doctors outside of visits) and barriers (including their own limited health knowledge and patients' lack of motivation to sustain hypertension self-management behaviors) that affect their efforts to support patients' hypertension self-management. CONCLUSION: African American patients with hypertension and their family members reported numerous patient, family, clinic, and community-level facilitators and barriers to patients' hypertension self-management. Patients' and their family members' views may help guide efforts to tailor behavioral interventions designed to improve hypertension self-management behaviors and hypertension control in minority populations.

Neuroepithelial circuit formed by innervation of sensory enteroendocrine cells.

Satiety and other core physiological functions are modulated by sensory signals arising from the surface of the gut. Luminal nutrients and bacteria stimulate epithelial biosensors called enteroendocrine cells. Despite being electrically excitable, enteroendocrine cells are generally thought to communicate indirectly with nerves through hormone secretion and not through direct cell-nerve contact. However, we recently uncovered in intestinal enteroendocrine cells a cytoplasmic process that we named neuropod. Here, we determined that neuropods provide a direct connection between enteroendocrine cells and neurons innervating the small intestine and colon. Using cell-specific transgenic mice to study neural circuits, we found that enteroendocrine cells have the necessary elements for neurotransmission, including expression of genes that encode pre-, post-, and transsynaptic proteins. This neuroepithelial circuit was reconstituted in vitro by coculturing single enteroendocrine cells with sensory neurons. We used a monosynaptic rabies virus to define the circuit's functional connectivity in vivo and determined that delivery of this neurotropic virus into the colon lumen resulted in the infection of mucosal nerves through enteroendocrine cells. This neuroepithelial circuit can serve as both a sensory conduit for food and gut microbes to interact with the nervous system and a portal for viruses to enter the enteric and central nervous systems.

Improving cold chain technologies through the use of phase change material

Gemstone Team FRESH

Stereocomplexes Formed From Select Oligomers of Polymer d-lactic Acid (PDLA) and l-lactate May Inhibit Growth of Cancer Cells and Help Diagnose Aggressive Cancers-Applications of the Warburg Effect.

It is proposed that select oligomers of polymer d-lactic acid (PDLA) will form a stereocomplex with l-lactate in vivo, producing lactate deficiency in tumor cells. Those cancer cells that utilize transport of lactate to maintain electrical neutrality may cease to multiply or die because of lactate trapping, and those cancer cells that benefit from utilization of extracellular lactate may be impaired. Intracellular trapping of lactate produces a different physiology than inhibition of LDH because the cell loses the option of shuttling pyruvate to an alternative pathway to produce an anion. Conjugated with stains or fluorescent probes, PDLA oligomers may be an agent for the diagnosis of tissue lactate and possibly cell differentiation in biopsy specimens. Preliminary experimental evidence is presented confirming that PDLA in high concentrations is cytotoxic and that l-lactate forms a presumed stereocomplex with PDLA. Future work should be directed at isolation of biologically active oligomers of PDLA.

On the modelling of the thermal interactions between a spray curtain and an impinging cold gas cloud

A mixed Lagrangian-Eulerian model of a Water Curtain barrier is presented. The heat, mass and momentum processes are modelled in a Lagrangian framework for the dispersed phase and in an Eulerian framework for the carrier phase. The derivation of the coupling source terms is illustrated with reference to a given carrier phase cell. The turbulent character of the flow is treated with a single equation model, modified to directly account for the influence of the particles on the flow. The model is implemented in the form of a 2 D incompressible Navier Stokes solver, coupled to an adaptive Rung Kutta method for the Lagrangian sub-system. Simulations of a free standing full cone water spray show satisfactory agreement with experiment. Predictions of a Water Curtain barrier impacted by a cold gas cloud point to markedly different flow fields for the upward and downward configurations, which could influence the effectiveness of chemical absorption in the liquid phase.

Modeling the dynamics of electromagnetically agitated metallurgical flows: levitation, cold crucible, aluminium electrolysis, etc.

We present practical modelling techniques for electromagnetically agitated liquid metal flows involving dynamic change of the fluid volume and shape during melting and the free surface oscillation. Typically the electromagnetic field is strongly coupled to the free surface dynamics and the heat-mass transfer. Accurate pseudo-spectral code and the k-omega turbulence model modified for complex and transitional flows with free surfaces are used for these simulations. The considered examples include magnetic suspension melting, induction scull remelting (cold crucible), levitation and aluminium electrolysis cells. The process control and the energy savings issues are analysed.

Investigation of the cold crucible melting process: experimental and numerical study

The dynamic process of melting different materials in a cold crucible is being studied experimentally with parallel numerical modelling work. The numerical simulation uses a variety of complementing models: finite volume, integral equation and pseudo-spectral methods combined to achieve the accurate description of the dynamic melting process. Results show the temperature history of the melting process with a comparison of the experimental and computed heat losses in the various parts of the equipment. The free surface visual observations are compared to the numerically predicted surface shapes.