Visible and Ultraviolet Laser Spectroscopy of ThF

The molecular ion ThF$^+$ is the species to be used in the next generation of search for the electron's Electric Dipole Moment (eEDM) at JILA. The measurement requires creating molecular ions in the eEDM sensitive state, the rovibronic ground state $^3\Delta_1$, $v^+=0$, $J^+=1$. Survey spectroscopy of neutral ThF is required to identify an appropriate intermediate state for a Resonance Enhanced Multi-Photon Ionization (REMPI) scheme that will create ions in the required state. We perform broadband survey spectroscopy (from 13000 to 44000~cm$^{-1}$) of ThF using both Laser Induced Fluorescence (LIF) and $1+1'$ REMPI spectroscopy. We observe and assign 345 previously unreported vibronic bands of ThF. We demonstrate 30\% efficiency in the production of ThF$^+$ ions in the eEDM sensitive state using the $\Omega = 3/2$ [32.85] intermediate state. In addition, we propose a method to increase the aforementioned efficiency to $\sim$100\% by using vibrational autoionization via core-nonpenetrating Rydberg states, and discuss theoretical and experimental challenges. Finally, we also report 83 vibronic bands of an impurity species, ThO.Comment: 49 pages, 7 figure

Assessment of agricultural contacts for market access in South Africa a smallholders' perspective

1. Objectives: This project intends to contribute to the on-going debate about whether and how restructured agri-food markets can provide viable market opportunities for small-scale farmers in Africa. It aims at analyzing contract farming from the smallholder perspective and at better understanding the implications for small-scale farmers regarding contractual arrangements, contractual choices and forms with processing and/or marketing firms. It also aims at assessing contract farming potential for poverty alleviation and at highlighting the conditions facilitating the integration of small-scale farmers in restructured markets. 2. Methodology: Studies conducted in South Africa will analyze farming systems and the livelihoods of farmers under contracting schemes. This entails the analysis of different types of contractual agreements linking small-scale farmers with processing and/or marketing firms leading to their integration into restructured markets. In addition it requires the examination of the local conditions and rural dynamics in which farmers engage in some type of contracting. Based on empirical research and a pluridisciplinary approach, the study will develop three major research topics: ? The characterization of small-scale contract farmers in terms of farming and marketing practices including product specificities; production system and system of activities; assets including land size, equipment, title deeds; and an assessment of their livelihoods conditions. ? In depth assessment of different types and forms of contracts in which these smallholders are engaged (i.e. specificity of contracts, opportunities, constraints and major obstacles) ? Analysis of the situations in which small-scale contract farmers operate, focusing on two levels: i) analysis at the community level to comprehend local agricultural product market dynamics, ii) local dynamics associated with national land and agricultural policies. 3. Significance of the proposed research: The modernization of markets, combined with the dismantling of international commodity agreements and the liberalization and restructuring of agricultural and agri-food markets, resulted in both the rise of supermarkets and the growth of contract farming in developing countries (Swinnen, 2007). Although contract farming could respond positively to the market access problems of small-scale farmers, the latter face many constraints on both the production side and the financial side. In this context, can African smallholders really benefit from contract farming? Is contract farming an effective way for smallholders to escape poverty? While the general trends of market restructuring have exclusionary effects on small-scale farmers, it is important to determine the suitability of contract farming (defined in its widest sense inclusive of marketing and production contracts as well as outgrower schemes) as a vehicle for linking small-scale farmers to agribusiness supply chains. Given the political imperative of social inclusion, it becomes necessary to analyze how to promote the conditions facilitating the integration of these farmers in restructured markets. 4. The research enabled to identify six types of contractual arrangements between farmers and buyers/agribusinesses: (i) Long term total integration contracts (Resource providing contracts); (ii) Short-term quasi-total integration contracts (Resource providing contracts); (iii) Production specification contracts (Production management contracts); (iv) Production management and market specification contracts (Production management and market specification contracts); (v) Certified market specification contracts (Market specification contracts); (vi) Ad hoc 'informal' contracts. Shaped according to and their efficiency depends on several internal and external factors. The results, however, show that contract farming is not a panacea for small-scale farmers. As such the results emphasizes pros and cons regarding co

High-Throughput Sequencing Enhanced Phage Display Identifies Peptides That Bind Mycobacteria

Bacterial cell wall components have been previously used as infection biomarkers detectable by antibodies. However, it is possible that the surface of the Mycobacterium tuberculosis (M. tb), the causative agent of tuberculosis (TB), also possesses molecules which might be non-antigenic. This makes the probing of biomarkers on the surface of M. tb cell wall difficult using antibodies. Here we demonstrate the use of phage display technology to identify peptides that bind to mycobacteria. We identified these clones using both random clone picking and high throughput sequencing. We demonstrate that random clone picking does not necessarily identify highly enriched clones. We further showed that the clone displaying the CPLHARLPC peptide which was identified by Illumina sequencing as the most enriched, binds better to mycobacteria than three clones selected by random picking. Using surface plasmon resonance, we showed that chemically synthesised CPLHARLPC peptide binds to a 15 KDa peptide from M.tb H37Rv whole cell lysates. These observations demonstrate that phage display technology combined with high-throughput sequencing is a powerful tool to identify peptides that can be used for investigating potential non-antigenic biomarkers for TB and other bacterial infections

Three applications of path integrals: equilibrium and kinetic isotope effects, and the temperature dependence of the rate constant of the [1,5] sigmatropic hydrogen shift in (Z)-1,3-pentadiene

Recent experiments have confirmed the importance of nuclear quantum effects even in large biomolecules at physiological temperature. Here we describe how the path integral formalism can be used to describe rigorously the nuclear quantum effects on equilibrium and kinetic properties of molecules. Specifically, we explain how path integrals can be employed to evaluate the equilibrium (EIE) and kinetic (KIE) isotope effects, and the temperature dependence of the rate constant. The methodology is applied to the [1,5] sigmatropic hydrogen shift in pentadiene. Both the KIE and the temperature dependence of the rate constant confirm the importance of tunneling and other nuclear quantum effects as well as of the anharmonicity of the potential energy surface. Moreover, previous results on the KIE were improved by using a combination of a high level electronic structure calculation within the harmonic approximation with a path integral anharmonicity correction using a lower level method.Comment: 9 pages, 4 figure

Neoliberalism and alternative food movements: markets, the state, and knowledge production in Southern California

Alternative food movements are promoted as solutions to environmental and social problems in the context of neoliberalism in the Unites States. Scholarly literature is divided over whether alternative food movements are reproducing the very structures of oppression they have sought to overcome, thus limiting the potential for systemic food change. My dissertation investigates how food justice is envisioned and practiced in this context through a qualitative research study of two alternative food projects in San Diego, California. One project is in a low-income, African American, and Latino locale, called Southeastern San Diego. They call themselves “Project New Village.” A second project is formed by white, affluent participants, located south of the city in the wild Tijuana River Estuary at the U.S. – Mexico border. They call themselves “San Diego Roots Sustainable Food Project.” These two movements emerge from San Diego’s history as two different trajectories. I found that by building a community garden and local farmers market, PNV is resisting the legacy of institutional racism, class inequality, city disinvestment, and supermarket abandonment that forged Southeastern as a space of exclusion. Not simply a project about food, PNV uses food as a tool to empower the neighborhood by engaging educational institutions in the project, creating employment opportunities through the garden and neighborhood market, forging community bonds, and teaching critical knowledge about food and nutrition from their perspective. Strategically using the garden and market as a tool to leverage city support, they can position themselves in ways that can advocate for policy transformation. The obstacles they face, such as that of law enforcement patrols interrupting their community rebuilding efforts, are very different hurdles than those faced by privileged settings. The location and affluence of SDRS leaders and participants lends a different approach to food justice work. I learned that SDRS is resisting the legacy of development in San Diego that has given rise to suburban sprawl, little land for farming, importing food to survive, and environmental destruction. SDRS challenges this past by creating local markets around sustainable food production. Building on sustainable agriculture by using permaculture, dry land farming techniques, and experimenting with the local habitat, SDRS is contributing to new knowledge about how to farm ecologically in San Diego. In addition to selling their produce at the farm and local venues, they work to create a new generation of sustainable farmers, and enlightened consumers

Broadband velocity modulation spectroscopy of HfF^+: towards a measurement of the electron electric dipole moment

Precision spectroscopy of trapped HfF^+ will be used in a search for the permanent electric dipole moment of the electron (eEDM). While this dipole moment has yet to be observed, various extensions to the standard model of particle physics (such as supersymmetry) predict values that are close to the current limit. We present extensive survey spectroscopy of 19 bands covering nearly 5000 cm^(-1) using both frequency-comb and single-frequency laser velocity-modulation spectroscopy. We obtain high-precision rovibrational constants for eight electronic states including those that will be necessary for state preparation and readout in an actual eEDM experiment.Comment: 13 pages, 7 figures, 3 table

On the Numerical Solution Of Schrodinger Equation

In the beginning, we start with reviewing basic concepts such as inner product and Hilbert spaces ; then we introduce Schrodinger Equation focusing on the solution of time–dependent and time–independent  with a stress on the harmonic oscillator  problem which will be the ingredient for our subject ; namely, the numerical solution of . The numerical solution of is then tackledusing the so–called potential morphing method .Calculations were carried  out for the ground state of the  which represents the frame of reference to work with. The obtained results were compared with similar ones and found to be in very good agreement. Finally, a brief discussion related to possible future work is given ; moreover recent  works on the subject are exposed t