Signal Processing Design of Low Probability of Intercept Waveforms

This thesis investigates a modification to Differential Phase Shift Keyed (DPSK) modulation to create a Low Probability of Interception/Exploitation (LPI/LPE) communications signal. A pseudorandom timing offset is applied to each symbol in the communications stream to intentionally create intersymbol interference (ISI) that hinders accurate symbol estimation and bit sequence recovery by a non-cooperative receiver. Two cooperative receiver strategies are proposed to mitigate the ISI due to symbol timing offset: a modified minimum Mean Square Error (MMSE) equalization algorithm and a multiplexed bank of equalizer filters determined by an adaptive Least Mean Square (LMS) algorithm. Both cooperative receivers require some knowledge of the pseudorandom symbol timing dither to successfully demodulate the communications waveform. Numerical Matlab® simulation is used to demonstrate the bit error rate performance of cooperative receivers and notional non-cooperative receivers for binary, 4-ary, and 8-ary DPSK waveforms transmitted through a line-of-sight, additive white Gaussian noise channel. Simulation results suggest that proper selection of pulse shape and probability distribution of symbol timing offsets produces a waveform that is accurately demodulated by the proposed cooperative receivers and significantly degrades non-cooperative receiver symbol estimation accuracy. In typical simulations, non-cooperative receivers required 2-8 dB more signal power than cooperative receivers to achieve a bit error rate of 1.0%. For nearly all reasonable parameter selections, non-cooperative receivers produced bit error rates in excess of 0.1%, even when signal power is unconstrained

p63 is an alternative p53 repressor in melanoma that confers chemoresistance and a poor prognosis.

The role of apoptosis in melanoma pathogenesis and chemoresistance is poorly characterized. Mutations in TP53 occur infrequently, yet the TP53 apoptotic pathway is often abrogated. This may result from alterations in TP53 family members, including the TP53 homologue TP63. Here we demonstrate that TP63 has an antiapoptotic role in melanoma and is responsible for mediating chemoresistance. Although p63 was not expressed in primary melanocytes, up-regulation of p63 mRNA and protein was observed in melanoma cell lines and clinical samples, providing the first evidence of significant p63 expression in this lineage. Upon genotoxic stress, endogenous p63 isoforms were stabilized in both nuclear and mitochondrial subcellular compartments. Our data provide evidence of a physiological interaction between p63 with p53 whereby translocation of p63 to the mitochondria occurred through a codependent process with p53, whereas accumulation of p53 in the nucleus was prevented by p63. Using RNA interference technology, both isoforms of p63 (TA and ΔNp63) were demonstrated to confer chemoresistance, revealing a novel oncogenic role for p63 in melanoma cells. Furthermore, expression of p63 in both primary and metastatic melanoma clinical samples significantly correlated with melanoma-specific deaths in these patients. Ultimately, these observations provide a possible explanation for abrogation of the p53-mediated apoptotic pathway in melanoma, implicating novel approaches aimed at sensitizing melanoma to therapeutic agents

Roman Character: Moral Foundations Theory and the Success of Rome

This study explores the six foundations in Jonathan Haidt’s Moral Foundations Theory and how they manifest in Livy’s History and Augustan policy. Their presence within each of those areas will demonstrate how strongly the foundations were entrenched in Roman culture and may help explain the successful transition from a republic to an empire by examining how these foundations encourage group cohesion. Added to this, this study may also help provide more support for Haidt’s theory. Moral Foundations Theory posits that there are six moral foundations of culture that have developed over time, each responding to a unique trigger: Care, Loyalty, Fairness, Authority, Liberty, and Sanctity. With the advent of culture, the way these foundations were triggered changed (i.e. some cultures only trigger some). Roman culture was able to trigger all six, which helped their civilization lasted so long. To explore this I analyzed the first ten books of Livy, finding many episodes in which the foundations were present (the ones presented are those in which the foundations are most prominent). I also looked at the way in which Augustan policy triggered the foundations thereby allowing the Romans to come back together after decades of civil war and aiding him in forming an empire which would last for centuries. The examples presented also display that these foundations are mutually reinforcing, that is several will occur in one situation thus making each other stronger. This study found that the foundations were abundantly present in Roman culture and their presence not only helps confirm Moral Foundations Theory but also allows us to see how Roman culture triggered these foundations

United States Intervention in Vietnam: A Critical Evaluation of Policy and Decisionmaking

81 leaves. Advisor: C. Walter ClarkThe United States intervened in South Vietnam in an attempt to prevent formation of a communist state there. The intervention was a failure; the country came under communist control. This thesis describes and analyzes the goals and policies of American intervention during the period 1950 through mid-1968. "United States-Vietnam Relations: 1945-1967", the Pentagon Papers, served as the primary source for defining the goals and policies. The writings of Bernard Fall were used to evaluate them. An operational definition of intervention proposed by James N. Rosenau was a framework for discussion. Rosenau defined intervention as an action that breaks sharply with the past and is directed at a nation's authority structure. The intervention was predicated on an assumption that monolithic communism threatened to spread over all of Indochina. The fear of communism was exaggerated. A more significant factor was the potency of Vietnamese nationalism, but this was not appreciated by American policymakers. They followed outmoded concepts of containment and relied too much on conventional military tactics that were incompatible with the political nature of the internal war in Vietnam

Keratinocyte Stem Cells: friends and foes

Skin and its appendages provide a protective barrier against the assaults of the environment. To perform its role, epidermis undergoes an ongoing renewal through a balance of proliferation and differentiation/apoptosis called homeostasis. Keratinocyte stem cells reside in a special microenvironment called niche in basal epidermis, adult hair follicle and sebaceous glands. While a definite marker has yet to be detected, data raised part in humans and part in the mouse system, point to a critical role of stem and its progeny transit amplifying cells in epidermal homeostasis. Stem cells are protected from apoptosis and are long-resident in adult epidermis. This renders them more prone to be the origin of skin cancer. In this review, we will outline the main features of adult stem cells in mouse and humans and discuss their fate in relation to differentiation, apoptosis and cancer

Transcriptomic profiling of Leishmania parasites and host macrophages during an infection

Leishmania parasites cause leishmaniasis, a group of diseases that range in manifestations from skin lesions to fatal visceral disease. The parasite's life cycle is divided between its insect vector and its mammalian host, where it resides primarily inside of macrophages. Once intracellular, Leishmania parasites must avoid being killed by the innate and adaptive immune responses. We performed transcriptomic profiling using RNA-seq to simultaneously identify global changes in gene expression in Leishmania parasites across multiple lifecycle stages and in infected macrophages from both murine and human hosts. Using a novel approach based on a dual statistical test to identify genes that were differentially expressed relative to both uninfected macrophages and macrophages that had ingested inert particles, we were able to filter out genes that were differentially regulated as part of a general phagocytic response and thereby select genes specific to Leishmania infection. The most substantial and dynamic Leishmania-specific differential expression responses were observed during early infection, while changes observed later were common to phagocytosis more generally. An evaluation of RNA processing events within the parasite revealed precise UTR boundaries for a majority of genes and widespread alternative trans-splicing and polyadenylation. Collection of data from multiple biological replicates, the use of matched host control samples, careful statistical analysis of variation, and removal of batch effects enabled the detection of biological differences between samples and timepoints with high confidence and sensitivity. Pathway and gene ontology analyses provided insights into the higher level processes activated across parasite developmental stages and during intracellular infection to reveal signatures of Leishmania differentiation and infection

Asynchrony of Gambierdiscus spp. abundance and toxicity in the U.S. Virgin Islands: implications for monitoring and management of Ciguatera

© The Author(s), 2021. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Liefer, J. D., Richlen, M. L., Smith, T. B., DeBose, J. L., Xu, Y., Anderson, D. M., & Robertson, A. Asynchrony of Gambierdiscus spp. abundance and toxicity in the U.S. Virgin Islands: implications for monitoring and management of Ciguatera. Toxins, 13(6), (2021): 413, https://doi.org/10.3390/toxins13060413.Ciguatera poisoning (CP) poses a significant threat to ecosystem services and fishery resources in coastal communities. The CP-causative ciguatoxins (CTXs) are produced by benthic dinoflagellates including Gambierdiscus and Fukuyoa spp., and enter reef food webs via grazing on macroalgal substrates. In this study, we report on a 3-year monthly time series in St. Thomas, US Virgin Islands where Gambierdiscus spp. abundance and Caribbean-CTX toxicity in benthic samples were compared to key environmental factors, including temperature, salinity, nutrients, benthic cover, and physical data. We found that peak Gambierdiscus abundance occurred in summer while CTX-specific toxicity peaked in cooler months (February–May) when the mean water temperatures were approximately 26–28 °C. These trends were most evident at deeper offshore sites where macroalgal cover was highest year-round. Other environmental parameters were not correlated with the CTX variability observed over time. The asynchrony between Gambierdiscus spp. abundance and toxicity reflects potential differences in toxin cell quotas among Gambierdiscus species with concomitant variability in their abundances throughout the year. These results have significant implications for monitoring and management of benthic harmful algal blooms and highlights potential seasonal and highly-localized pulses in reef toxin loads that may be transferred to higher trophic levels.This work was funded in part by the National Oceanic and Atmospheric Administration, Ecology and Oceanography of Harmful Algal Blooms Program (ECOHAB publication number 984) through the CiguaHAB project (NA11NOS4780028), and also contributes to CIGUATOX (NA17NOS4780181) granted to coauthors AR, TBS, DMA, and MLR. Additional support was provided by NSF Partnerships in International Research and Education (1743802), and the Greater Caribbean Center for Ciguatera Research (NIH 1P01ES028949-01 and NSF 1841811). Financial support of YX was from the National Natural Science Foundation of China (41976155), the Natural Science Foundation of Guangxi Province (2020GXNSFDA297001)

Basin-scale biogeography of marine phytoplankton reflects cellular-scale optimization of metabolism and physiology

Extensive microdiversity within Prochlorococcus, the most abundant marine cyanobacterium, occurs at scales from a single droplet of seawater to ocean basins. To interpret the structuring role of variations in genetic potential, as well as metabolic and physiological acclimation, we developed a mechanistic constraint-based modeling framework that incorporates the full suite of genes, proteins, metabolic reactions, pigments, and biochemical compositions of 69 sequenced isolates spanning the Prochlorococcus pangenome. Optimizing each strain to the local, observed physical and chemical environment along an Atlantic Ocean transect, we predicted variations in strain-specific patterns of growth rate, metabolic configuration, and physiological state, defining subtle niche subspaces directly attributable to differences in their encoded metabolic potential. Predicted growth rates covaried with observed ecotype abundances, affirming their significance as a measure of fitness and inferring a nonlinear density dependence of mortality. Our study demonstrates the potential to interpret global-scale ecosystem organization in terms of cellular-scale processes

Pseudo-nitzschia physiological ecology, phylogeny, toxicity, monitoring and impacts on ecosystem health

This paper is not subject to U.S. copyright. The definitive version was published in Harmful Algae 14 (2012): 271-300, doi:10.1016/j.hal.2011.10.025.Over the last decade, our understanding of the environmental controls on Pseudo-nitzschia blooms and domoic acid (DA) production has matured. Pseudo-nitzschia have been found along most of the world's coastlines, while the impacts of its toxin, DA, are most persistent and detrimental in upwelling systems. However, Pseudo-nitzschia and DA have recently been detected in the open ocean's high-nitrate, low-chlorophyll regions, in addition to fjords, gulfs and bays, showing their presence in diverse environments. The toxin has been measured in zooplankton, shellfish, crustaceans, echinoderms, worms, marine mammals and birds, as well as in sediments, demonstrating its stable transfer through the marine food web and abiotically to the benthos. The linkage of DA production to nitrogenous nutrient physiology, trace metal acquisition, and even salinity, suggests that the control of toxin production is complex and likely influenced by a suite of environmental factors that may be unique to a particular region. Advances in our knowledge of Pseudo-nitzschia sexual reproduction, also in field populations, illustrate its importance in bloom dynamics and toxicity. The combination of careful taxonomy and powerful new molecular methods now allow for the complete characterization of Pseudo-nitzschia populations and how they respond to environmental changes. Here we summarize research that represents our increased knowledge over the last decade of Pseudo-nitzschia and its production of DA, including changes in worldwide range, phylogeny, physiology, ecology, monitoring and public health impacts

Ritzel, Department of Health Education and Recreation

Abstract The occurrence of injuries in the home environment is common to older adults, especially elderly women, in most developed countries. The research literature on this subject is reviewed. This paper also identifies some of the situations that occur that lead to injury and that could also be responsive to preventive efforts