“Giving back the gaze”: exploring complex and multifarious self-representations in the work of Myra Greene and Renée Cox

In this thesis I explore photographic attempts by African American women artists to produce experimental and diverse self-representations of the black female body. It considers the works of two black women photographers, Myra Greene and Renée Cox, and their contribution to a new visual language that focuses on abstractions and multifarious depictions of the black female body to explore the ever shifting identity of African Americans. The first chapter focuses on photographer Myra Greene and how she embraces abstraction, ambiguity and obfuscation as a form of intellectual and aesthetic empowerment. The artist deliberately complicates readings of her body in order to decentre the black body and shift it out from under the intense scrutiny of the ethnographic gaze. The second chapter examines the work of Renée Cox. It is an interdisciplinary analysis of the artist’s multifarious and multilayered self-representations to reflect the impossibility of defining the black female experience as one monolithic construct. By engaging with ideas of recontextulisation, reappropriation and inversion, both photographers are self-aware rather than complicit in the perpetuation of the black woman’s body in exhibition. They deliberately embrace notions of hybridity and ambiguity to defy single interpretation and contest ways in which the black female body continues to be read through representation of the past. This thesis considers the importance of positioning these women in a larger artistic movement of African American women artists who explore similar systems of observing and defining the black female body. In very different ways, Cox and Greene both challenge derogatory cultural and historical representations. I will explore their artistic efforts to reinstate and appropriate self-representations in a black female creative paradigm, for purposes of individual and communal empowerment

Victimization in Homeless African American Women and their High-Risk Behaviors: Implication for Counselors

Victimization is an increasing concern among homeless African American women. This study’s aim was to investigate victimization factors (e.g., sexual assault, physical assault, and domestic violence) and its prevalence and effects on African American women high risk behaviors while homeless. Participants were 200 homeless African American women (ages, 18 years to 65 years and above) receiving services from clinics, shelters, and community agencies. The authors examined the predictive power of victimization factors (e.g., sexual assault, physical assault, and domestic violence) of homeless African American women on the number of substance use per week in a large metropolitan area in the Southern region of the United States. Using both multiple and logistic regression tests, the authors were able to find correlations in the variables. Results indicated that physical assault and domestic violence were found to be independently related to the number of substance use per week among homeless African American women

Contribution of Company Affiliation and Social Contacts to Risk Estimates of Between-Farm Transmission of Avian Influenza

BACKGROUND: Models of between-farm transmission of pathogens have identified service vehicles and social groups as risk factors mediating the spread of infection. Because of high levels of economic organization in much of the poultry industry, we examined the importance of company affiliation, as distinct from social contacts, in a model of the potential spread of avian influenza among broiler poultry farms in a poultry-dense region in the United States. The contribution of company affiliation to risk of between-farm disease transmission has not been previously studied. METHODOLOGY/PRINCIPAL FINDINGS: We obtained data on the nature and frequency of business and social contacts through a national survey of broiler poultry growers in the United States. Daily rates of contact were estimated using Monte Carlo analysis. Stochastic modeling techniques were used to estimate the exposure risk posed by a single infectious farm to other farms in the region and relative risk of exposure for farms under different scenarios. The mean daily rate of vehicular contact was 0.82 vehicles/day. The magnitude of exposure risk ranged from <1% to 25% under varying parameters. Risk of between-farm transmission was largely driven by company affiliation, with farms in the same company group as the index farm facing as much as a 5-fold increase in risk compared to farms contracted with different companies. Employment of part-time workers contributed to significant increases in risk in most scenarios, notably for farms who hired day-laborers. Social visits were significantly less important in determining risk. CONCLUSIONS/SIGNIFICANCE: Biosecurity interventions should be based on information on industry structure and company affiliation, and include part-time workers as potentially unrecognized sources of viral transmission. Modeling efforts to understand pathogen transmission in the context of industrial food animal production should consider company affiliation in addition to geospatial factors and pathogen characteristics. Restriction of social contacts among farmers may be less useful in reducing between-farm transmission

SpoT Induces Intracellular Salmonella Virulence Programs in the Phagosome.

Guanosine tetraphosphate (ppGpp) and guanosine pentaphosphate (pppGpp), together named (p)ppGpp, regulate diverse aspects of Salmonella pathogenesis, including synthesis of nutrients, resistance to inflammatory mediators, and expression of secretion systems. In Salmonella, these nucleotide alarmones are generated by the synthetase activities of RelA and SpoT proteins. In addition, the (p)ppGpp hydrolase activity of the bifunctional SpoT protein is essential to preserve cell viability. The contribution of SpoT to physiology and pathogenesis has proven elusive in organisms such as Salmonella, because the hydrolytic activity of this RelA and SpoT homologue (RSH) is vital to prevent inhibitory effects of (p)ppGpp produced by a functional RelA. Here, we describe the biochemical and functional characterization of a spoT-Δctd mutant Salmonella strain encoding a SpoT protein that lacks the C-terminal regulatory elements collectively referred to as "ctd." Salmonella expressing the spoT-Δctd variant hydrolyzes (p)ppGpp with similar kinetics to those of wild-type bacteria, but it is defective at synthesizing (p)ppGpp in response to acidic pH. Salmonella spoT-Δctd mutants have virtually normal adaptations to nutritional, nitrosative, and oxidative stresses, but poorly induce metal cation uptake systems and Salmonella pathogenicity island 2 (SPI-2) genes in response to the acidic pH of the phagosome. Importantly, spoT-Δctd mutant Salmonella replicates poorly intracellularly and is attenuated in a murine model of acute salmonellosis. Collectively, these investigations indicate that (p)ppGpp synthesized by SpoT serves a unique function in the adaptation of Salmonella to the intracellular environment of host phagocytes that cannot be compensated by the presence of a functional RelA.IMPORTANCE Pathogenic bacteria experience nutritional challenges during colonization and infection of mammalian hosts. Binding of the alarmone nucleotide guanosine tetraphosphate (ppGpp) to RNA polymerase coordinates metabolic adaptations and virulence gene transcription, increasing the fitness of diverse Gram-positive and Gram-negative bacteria as well as that of actinomycetes. Gammaproteobacteria such as Salmonella synthesize ppGpp by the combined activities of the closely related RelA and SpoT synthetases. Due to its profound inhibitory effects on growth, ppGpp must be removed; in Salmonella, this process is catalyzed by the vital hydrolytic activity of the bifunctional SpoT protein. Because SpoT hydrolase activity is essential in cells expressing a functional RelA, we have a very limited understanding of unique roles these two synthetases may assume during interactions of bacterial pathogens with their hosts. We describe here a SpoT truncation mutant that lacks ppGpp synthetase activity and all C-terminal regulatory domains but retains excellent hydrolase activity. Our studies of this mutant reveal that SpoT uniquely senses the acidification of phagosomes, inducing virulence programs that increase Salmonella fitness in an acute model of infection. Our investigations indicate that the coexistence of RelA/SpoT homologues in a bacterial cell is driven by the need to mount a stringent response to a myriad of physiological and host-specific signatures

The role of adjuvant in mediating antigen structure and stability

The purpose of this study was to probe the fate of a model antigen, a cysteine-free mutant of bacteriophage T4 lysozyme, to the level of fine structural detail, as a consequence of its interaction with an aluminum (Al)-containing adjuvant. Fluorescence spectroscopy and differential scanning calorimetry were used to compare the thermal stability of the protein in solution versus adsorbed onto an Al-containing adjuvant. Differences in accessible hydrophobic surface areas were investigated using an extrinsic fluorescence probe, 8-Anilino-1-naphthalenesulfonic acid (ANS). As has been observed with other model antigens, the apparent thermal stability of the protein decreased following adsorption onto the adjuvant. ANS spectra suggested that adsorption onto the adjuvant caused an increase in exposure of hydrophobic regions of the protein. Electrostatic interactions drove the adsorption, and disruption of these interactions with high ionic strength buffers facilitated the collection of two-dimensional 15N heteronuclear single quantum coherence nuclear magnetic resonance data of protein released from the adjuvant. Although the altered stability of the adsorbed protein suggested changes to the protein\u27s structure, the fine structure of the desorbed protein was nearly identical to the protein\u27s structure in the adjuvant-free formulation. Thus, the adjuvant-induced changes to the protein that were responsible for the reduced thermal stability were not observed upon desorption. © 2011 Wiley Periodicals, Inc

The Biogeography of Putative Microbial Antibiotic Production

Understanding patterns in the distribution and abundance of functional traits across a landscape is of fundamental importance to ecology. Mapping these distributions is particularly challenging for species-rich groups with sparse trait measurement coverage, such as flowering plants, insects, and microorganisms. Here, we use likelihood-based character reconstruction to infer and analyze the spatial distribution of unmeasured traits. We apply this framework to a microbial dataset comprised of 11,732 ketosynthase alpha gene sequences extracted from 144 soil samples from three continents to document the spatial distribution of putative microbial polyketide antibiotic production. Antibiotic production is a key competitive strategy for soil microbial survival and performance. Additionally, novel antibiotic discovery is highly relevant to human health, making natural antibiotic production by soil microorganisms a major target for bioprospecting. Our comparison of trait-based biogeographical patterns to patterns based on taxonomy and phylogeny is relevant to our basic understanding of microbial biogeography as well as the pressing need for new antibiotics

Store-directed price promotions and communications strategies improve healthier food supply and demand: impact results from a randomized controlled, Baltimore City store-intervention trial

Abstract Objective Small food store interventions show promise to increase healthy food access in under-resourced areas. However, none have tested the impact of price discounts on healthy food supply and demand. We tested the impact of store-directed price discounts and communications strategies, separately and combined, on the stocking, sales and prices of healthier foods and on storeowner psychosocial factors. Design Factorial design randomized controlled trial. Setting Twenty-four corner stores in low-income neighbourhoods of Baltimore City, MD, USA. Subjects Stores were randomized to pricing intervention, communications intervention, combined pricing and communications intervention, or control. Stores that received the pricing intervention were given a 10–30 % price discount by wholesalers on selected healthier food items during the 6-month trial. Communications stores received visual and interactive materials to promote healthy items, including signage, taste tests and refrigerators. Results All interventions showed significantly increased stock of promoted foods v . control. There was a significant treatment effect for daily unit sales of healthy snacks ( β =6·4, 95 % CI 0·9, 11·9) and prices of healthy staple foods ( β =–0·49, 95 % CI –0·90, –0·03) for the combined group v . control, but not for other intervention groups. There were no significant intervention effects on storeowner psychosocial factors. Conclusions All interventions led to increased stock of healthier foods. The combined intervention was effective in increasing sales of healthier snacks, even though discounts on snacks were not passed to the consumer. Experimental research in small stores is needed to understand the mechanisms by which store-directed price promotions can increase healthy food supply and demand

Escargot maintains stemness and suppresses differentiation in Drosophila intestinal stem cells

Snail family transcription factors are expressed in various stem cell types, but their function in maintaining stem cell identity is unclear. In the adult Drosophila midgut, the Snail homolog Esg is expressed in intestinal stem cells (ISCs) and their transient undifferentiated daughters, termed enteroblasts (EB). We demonstrate here that loss of esg in these progenitor cells causes their rapid differentiation into enterocytes (EC) or entero‐endocrine cells (EE). Conversely, forced expression of Esg in intestinal progenitor cells blocks differentiation, locking ISCs in a stem cell state. Cell type‐specific transcriptome analysis combined with Dam‐ID binding studies identified Esg as a major repressor of differentiation genes in stem and progenitor cells. One critical target of Esg was found to be the POU‐domain transcription factor, Pdm1, which is normally expressed specifically in differentiated ECs. Ectopic expression of Pdm1 in progenitor cells was sufficient to drive their differentiation into ECs. Hence, Esg is a critical stem cell determinant that maintains stemness by repressing differentiation‐promoting factors, such as Pdm1