ScholarWorks@UMassAmherst
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Recent Submissions
Publication Universal finite-size amplitude and anomalous entanglement entropy of z = 2 quantum Lifshitz criticalities in topological chains(2022)We consider Lifshitz criticalities with dynamical exponent z = 2 that emerge in a class of topological chains. There, such a criticality plays a fundamental role in describing transitions between symmetry-enriched conformal field theories (CFTs). We report that, at such critical points in one spatial dimension, the finite-size correction to the energy scales with system size, L, as ∼ L −2 , with universal and anomalously large coefficient. The behavior originates from the specific dispersion around the Fermi surface, ε ∝ ±k 2 . We also show that the entanglement entropy exhibits at the criticality a non-logarithmic dependence on l/L, where l is the length of the sub-system. In the limit of l L, the maximally-entangled ground state has the entropy, S(l/L) = S0 + 2n(l/L) log(l/L). Here S0 is some non-universal entropy originating from short-range correlations, and n is a half-integer or integer depending on the degrees of freedom in the model. We show that the novel entanglement originates from the long-range correlation mediated by a zero mode in the low energy sector. The work paves the way to study finite-size effects and entanglement entropy around Lifshitz criticalities and offers an insight into transitions between symmetry-enriched criticalities.Publication Murine macrophage-based iNos reporter reveals polarization and reprogramming in the context of breast cancer(2023-04)As part of the first line of defense against pathogens, macrophages possess the ability to differentiate into divergent phenotypes with varying functions. The process by which these cells change their characteristics, commonly referred to as macrophage polarization, allows them to change into broadly pro-inflammatory (M1) or anti-inflammatory (M2) subtypes, and depends on the polarizing stimuli. Deregulation of macrophage phenotypes can result in different pathologies or affect the nature of some diseases, such as cancer and atherosclerosis. Therefore, a better understanding of macrophage phenotype conversion in relevant models is needed to elucidate its potential roles in disease. However, there are few existing probes to track macrophage changes in multicellular environments. In this study, we generated an eGFP reporter cell line based on inducible nitric oxide synthase (iNos) promoter activity in RAW264.7 cells (RAW:iNos-eGFP). iNos is associated with macrophage activation to pro-inflammatory states and decreases in immune-suppressing ones. We validated the fidelity of the reporter for iNos following cytokine-mediated polarization and confirmed that reporter and parental cells behaved similarly. RAW:iNos-eGFP cells were then used to track macrophage responses in different in vitro breast cancer models, and their re-education from anti- to pro-inflammatory phenotypes via a previously reported pyrimido(5,4-b)indole small molecule, PBI1. Using two mouse mammary carcinoma cell lines, 4T1 and EMT6, effects on macrophages were assessed via conditioned media, two-dimensional/monolayer co-culture, and three-dimensional spheroid models. While conditioned media derived from 4T1 or EMT6 cells and monolayer co-cultures of each cancer cell line with RAW:iNos-eGFP cells all resulted in decreased fluorescence, the trends and extents of effects differed. We also observed decreases in iNos-eGFP signal in the macrophages in co-culture assays with 4T1- or EMT6-based spheroids. We then showed that iNos production is enhanced in these cancer models using PBI1, tracking increased fluorescence. Collectively, this work demonstrates that this reporter-based approach provides a facile means to study macrophage responses in complex, multicomponent environments. Beyond the initial studies presented here, this platform can be used with a variety of in vitro models and extended to in vivo applications with intravital imaging.Publication Environmental factors influencing detection efficiency of an acoustic telemetry array and consequences for data interpretation(2023)Background Acoustic telemetry is a commonly used technology to monitor animal occupancy and infer movement in aquatic environments. The information that acoustic telemetry provides is vital for spatial planning and management decisions concerning aquatic and coastal environments by characterizing behaviors and habitats such as spawning aggregations, migrations, corridors, and nurseries, among others. However, performance of acoustic telemetry equipment and resulting detection ranges and efficiencies can vary as a function of environmental conditions, leading to potentially biased interpretations of telemetry data. Here, we characterize variation in detection performance using an acoustic telemetry receiver array deployed in Wellfleet Harbor, Massachusetts, USA from 2015 to 2017. The array was designed to study benthic invertebrate movements and provided an in situ opportunity to identify factors driving variation in detection probability. Results The near-shore location proximate to environmental monitoring allowed for a detailed examination of factors influencing detection efficiency in a range-testing experiment. Detection ranges varied from < 50 to 1,500 m and efficiencies varied from 0 to 100% within those detection ranges. Detection efficiency was affected by distance, wind speed and direction, wave height and direction, water temperature, water depth, and water quality. Conclusions Performance of acoustic telemetry systems is strongly contingent on environmental conditions. Our study found that wind, waves, water temperature, water quality, and depth all affected performance to an extent that could seriously compromise a study if these effects were not taken into consideration. Other unmeasured factors may also be important, depending on the characteristics of each site. This information can help guide future telemetry study designs by helping researchers anticipate the density of receivers required to achieve study objectives. Researchers can further refine and document the reliability of their data by incorporating continuously deployed range-testing tags and prior knowledge on varying detection efficiency into movement and occupancy models.Publication An Application of the Contingent Valuation Method to Groundwater Quality in Western Massachusetts(1995-02)The objectives of this thesis are to: 1. Establish links among individual attitudes, beliefs, experiences and actions, and determine how these factors affect elicited willingness to pay for groundwater protection. 2. Determine the role of information: How does information (such as water testing) and uncertainty regarding groundwater quality affect individual behavior and willingness to pay (WTP) for groundwater quality? 3. Determine the motivations underlying elicited willingness to pay. 4. Analyze whether individuals in communities which have suffered contamination behave differently from those who have not. 5. Analyze the differences between WTP to protect one's own supply (use value) and WTP to protect an entire aquifer (use plus nonuse value).Publication CIE Bricolage - 1968-1998(Center for International Education, UMass Amherst, 1998-08)
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