4,849 research outputs found

    The Stamp Act: Revolutionary Resistance in New York

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    Prior to the first battles of the American Revolution, the BritishParliament imposed several duties on the American colonies to fund the expenses of the French and Indian War, continued attacks on the American frontier, taxed American colonists to assist with British finances, and garrisoned troops throughout America. One of these duties, the American Stamp Act, was passed and enacted in early 1765 throughout the North American British colonies. The correlation between battles, campaigns, and acts such as imposed duties, are all interrelated. Many historians traditionally view the colonial reaction to the Stamp Act as one singular political event or overshadowed by the battles fought in the war for American independence. This thesis has been written to examine the social and economic impact of the American Stamp Act of 1765, and to investigate the enforcement practices and reactions of those affected by the act, specifically in the colony of New York, and its impact on the subsequent war for American independence. The materials utilized in this study include both primary and secondary sources. The secondary sources aim to ensure a rounded understanding of the Stamp Act and pre-Revolutionary thought, while primary sources have been examined to understand specific localities as issues surrounding the Stamp Act unraveled. In this study, a more in-depth examination into the authority that enforced the Act, the relationship, and interactions between those affected and those who collected the levy, the various motives of opposition, and the eventual formation of organized resistance and action within New York in the broader context of colonial America are explored

    Ailanthus altissima Aqueous Extract Deters Spodoptera frugiperda Oviposition

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    Ailanthus altissima (Mill.) Swingle (Simaroubaceae), the tree of heaven, is a highly invasive tree species containing phytochemicals with a range of biological activities. Exposure to novel chemistry from invasive plant species may result in changes to established Lepidopteran behaviors, including feeding or oviposition. However, the impact of A. altissima chemistry on insect behavior has not been extensively explored. Therefore, A. altissima extract was tested for oviposition deterrence effects against Spodoptera frugiperda (Smith) (Noctuidae). Oviposition substrates were treated with water-soluble extractions of Zea mays (L), A. altissima, or a combination of both. Moths were then placed in chambers containing different substrate treatments and allowed to oviposit. Given choice, S. frugiperda demonstrated a higher percentage of egg deposition on Z. mays treated substrate compared to water treated substrate or A. altissima treated substrate. Significantly, when Z. mays treated substrate was subsequently treated with A. altissima extract, S. frugiperda was deterred from laying eggs on its preferred substrate (Z. mays) in a concentration-dependent manner. This observed change in behavior suggests that the deterrent properties of A. altissima phytochemicals may have economically important crop protection applications in controlling pest species like S. frugiperda

    Plant extract efficacy on mosquito mortality: preliminary studies on the effect of Ailanthus altissima extract on adult Aedes aegypti and Culex quinquefasciatus

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    Abstract Due to the negative environmental impact and resistance to synthetic insecticides, the development of biological control has increased significantly over the past half century with the potential of plant extracts only recently attracting attention. The purpose of this preliminary study was to examine the potential of Ailanthus altissima extract as a botanical insecticide on adult mosquitoes. Two species of mosquitoes (Aedes aegypti and Culex quinquefasciatus) and a non-target lepidopteran species, Painted Lady butterfly (Vanessa cardui) were treated with A. altissima extract from new, mature, and senesced leaflets using serial dilutions (0, 25, 50, 75, 100%) of extract via two application methods (aerosol and sugar feeding). We found that application method and leaf age had significant effects on mosquito mortality at high concentrations. These findings indicate that while mortality was not significantly high compared to commercial products, there may be potential to use an invasive plant extract as a bio-control tool for mosquito vectors of human disease pathogens

    Cosmological foundations revisited with Pantheon+

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    We reanalyse the Pantheon+ supernova catalogue to compare a cosmology with non-FLRW evolution, the "timescape cosmology", with the standard Λ\LambdaCDM cosmology. To this end, we consider the Pantheon+ supernova catalogue, which is the largest available Type Ia supernova dataset for a geometric comparison between the two models. We construct a covariance matrix to be as independent of cosmology as possible, including independence from the FLRW geometry and peculiar velocity with respect to FLRW average evolution. Within this framework, which goes far beyond most other definitions of "model independence", we introduce new statistics to refine Type Ia supernova (SneIa) light-curve analysis. In addition to conventional galaxy correlation functions used to define the scale of statistical homogeneity we introduce empirical statistics which enables a refined analysis of the distribution biases of SneIa light-curve parameters βc\beta c and αx1\alpha x_1. For lower redshifts, the Bayesian analysis highlights important features attributable to the increased number of low-redshift supernovae, the artefacts of model-dependent light-curve fitting and the cosmic structure through which we observe supernovae. This indicates the need for cosmology-independent data reduction to conduct a stronger investigation of the emergence of statistical homogeneity and to compare alternative cosmologies in light of recent challenges to the standard model. "Dark energy" is generally invoked as a place-holder for "new physics". Our from-first-principles reanalysis of the Pantheon+ catalogue supports future deeper studies of the interplay of matter and nonlinear spacetime geometry, in a data-driven setting. For the first time in 25 years, we find evidence that the Pantheon+ catalogue already contains such a wealth of data that with further reanalysis, a genuine "paradigm shift" may soon emerge. [Abridged]Comment: 23 pages, 14 figures, 3 table

    The effects of moderate prenatal alcohol exposure on the organization of exploratory behavior by adult female rats

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    A large body of research has indicated that moderate Prenatal Alcohol Exposure (PAE - 60 mg/dl peak BAC) can produce impairments on cognitive processes, such as spatial learning and memory. The neurobiological basis of these impairments is poorly understood but is frequently linked to alterations in hippocampal functioning. Although the hippocampus has a central role in learning and memory, damage to the hippocampus can also produce impairments in locomotor and exploratory behaviors by rodents (reviewed in Thompson et al., 2018). Rodent exploratory behavior is organized around home bases, which serves as central points of attraction from which rats and mice organize their exploratory trips into the remaining environment. We are unaware of studies investigating the relationship between moderate prenatal alcohol exposure and exploratory behavior. Thus, in the present study, we tested adult female rats in two experiments where they were allowed to freely explore a circular open field for ~30min. Here, we report that, with respect to home base behavior, exploratory movements were largely intact in rats exposed to alcohol prenatally. Specifically, animals rapidly established home bases within 5min of the beginning of testing and the bases were established in one or two locations in the environment. They made exploratory trips away and back to the home base and made several stops at this location along with bouts of grooming behavior. The results are discussed with respect to theories of hippocampal function and the impact of moderate prenatal alcohol on spatial behavior

    Assessing risk for HIV infection among adolescent girls in South Africa: an evaluation of the VOICE risk score (HPTN 068)

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    INTRODUCTION: To maximize impact and minimize costs, antiretroviral pre-exposure prophylaxis (PrEP) interventions should be offered to those at highest risk for HIV infection. The risk score derived from the VOICE trial is one tool currently being utilized to determine eligibility in adolescent PrEP trials in sub-Saharan Africa. This study is aimed at evaluating the utility of the risk score in predicting HIV incidence among a cohort of adolescent girls in rural South Africa. METHODS: We utilized data from HIV Prevention Trials Network (HPTN) 068, a phase III randomized controlled trial conducted in rural Mpumalanga province, South Africa. School-attending young women aged 13 to 20 years were enrolled into the trial from 2011 to 2012 and followed for up to three years. A risk score based on individual-level risk factors measured at enrolment was calculated for HPTN 068 participants who completed a one-year follow-up visit and were HIV seronegative at enrolment. Possible scores ranged from 0 to 10. A proportional hazards model was then used to determine if risk score at enrolment was predictive of incident HIV infection at follow-up and an area under the curve analysis was used to examine the predictive ability of the score. RESULTS AND DISCUSSION: The risk score had limited variability in the HPTN 068 sample. Scores ≥5 identified 85% of incident infections from 94% of the sample, compared to the VOICE sample in which scores ≥5 identified 91% of incident infections from only 64% of participants. The risk score did not predict HIV incidence after one year of follow-up (hazard ratio = 1.029; 95% confidence interval (CI): 0.704, 1.503, p = .884) and showed poor predictive ability (area under the curve = 0.55; 95% CI: 0.44, 0.65). Certain individual risk factors that comprise the risk score may be context specific or not relevant for adolescent populations. Additional factors should be considered when assessing risk for the purposes of determining PrEP eligibility. CONCLUSIONS: The VOICE risk score demonstrated low utility to predict HIV incidence in the HPTN 068 sample. Findings highlight the need for an age and developmentally appropriate tool for assessing risk for HIV infection among adolescents. Use of the VOICE risk score for determining PrEP eligibility in younger populations should be carefully considered

    Mineral deposition and vascular invasion of hydroxyapatite reinforced collagen scaffolds seeded with human adipose-derived stem cells

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    Background: Collagen-based scaffolds reinforced with hydroxyapatite (HA) are an attractive choice for bone tissue engineering because their composition mimics that of bone. We previously reported the development of compression-molded collagen-HA scaffolds that exhibited high porosity, interconnected pores, and mechanical properties that were well-suited for surgical handling and fixation. The objective of this study was to investigate these novel collagen-HA scaffolds in combination with human adipose-derived stem cells (hASCs) as a template for bone formation in a subcutaneous athymic mouse model. Methods: Collagen-HA scaffolds and collagen-only scaffolds were fabricated as previously described, and a clinically approved bone void filler was used as a control for the material. Constructs were seeded with hASCs and were pre-treated with either control or osteogenic media. A cell-free group was also included. Scaffolds were implanted subcutaneously in the backs of athymic nude mice for 8 weeks. Mineral deposition was quantified via micro-computed tomography. Histological and immunofluorescence images of the explants were used to analyze their vascular invasion, remodeling and cellularity. Results: Cell-free collagen-HA scaffolds and those that were pre-seeded with osteogenically differentiated hASCs supported mineral deposition and vascular invasion at comparable rates, while cell-seeded constructs treated with the control medium showed lower mineralization after implantation. HA-reinforcement allowed collagen constructs to maintain their shape, provided improved cell-tissue-scaffold integration, and resulted in a more organized tissue when pre-treated in an osteogenic medium. Scaffold type and pre-treatment also determined osteoclast activity and therefore potential remodeling of the constructs. Conclusions: The results of this study cumulatively indicate that treatment medium and scaffold composition direct mineralization and angiogenic tissue formation in an ectopic model. The data suggest that it may be necessary to match the scaffold with a particular cell type and cell-specific pre-treatment to achieve optimal bone formation

    Influence of Total Western Diet on Docosahexaenoic Acid Suppression of Silica-Triggered Lupus Flaring in NZBWF1 Mice

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    Lupus is a debilitating multi-organ autoimmune disease clinically typified by periods of flare and remission. Exposing lupus-prone female NZBWF1 mice to crystalline silica (cSiO2), a known human autoimmune trigger, mimics flaring by inducing interferon-related gene (IRG) expression, inflammation, ectopic lymphoid structure (ELS) development, and autoantibody production in the lung that collectively accelerate glomerulonephritis. cSiO2-triggered flaring in this model can be prevented by supplementing mouse diet with the ω-3 polyunsaturated fatty acid (PUFA) docosahexaenoic acid (DHA). A limitation of previous studies was the use of purified diet that, although optimized for rodent health, does not reflect the high American intake of saturated fatty acid (SFA), ω-6 PUFAs, and total fat. To address this, we employed here a modified Total Western Diet (mTWD) emulating the 50th percentile U.S. macronutrient distribution to discern how DHA supplementation and/or SFA and ω-6 reduction influences cSiO2-triggered lupus flaring in female NZBWF1 mice. Six-week-old mice were fed isocaloric experimental diets for 2 wks, intranasally instilled with cSiO2 or saline vehicle weekly for 4 wks, and tissues assessed for lupus endpoints 11 wks following cSiO2 instillation. In mice fed basal mTWD, cSiO2 induced robust IRG expression, proinflammatory cytokine and chemokine elevation, leukocyte infiltration, ELS neogenesis, and autoantibody production in the lung, as well as early kidney nephritis onset compared to vehicle-treated mice fed mTWD. Consumption of mTWD containing DHA at the caloric equivalent to a human dose of 5 g/day dramatically suppressed induction of all lupus-associated endpoints. While decreasing SFA and ω-6 in mTWD modestly inhibited some disease markers, DHA addition to this diet was required for maximal protection against lupus development. Taken together, DHA supplementation at a translationally relevant dose was highly effective in preventing cSiO2-triggered lupus flaring in NZBWF1 mice, even against the background of a typical Western diet
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