23 research outputs found

    Unveiling Meaning: The Pitt County Confederate Soldiers' Monument

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    In recent years, the meanings of Confederate monuments have become a topic of public debate. Some argue that Confederate monuments are simply memorials for fallen Confederate soldiers and thus stand as reverent commemorations of Southern ancestors. Others argue that these monuments, produced by a post-war Southern propaganda effort, stand as relics of the Jim Crow era and are thus hateful pieces of cultural geography. This case study of the Pitt County Confederate Soldiers’ Monument, which stood in Greenville, NC from 1914 until 2020, attempts to define the meaning of the monument through an analysis of its unveiling ceremony. Sentiments expressed and ritualistic acts performed at unveiling ceremonies can provide evidence of the motives and intentions of the monuments’ creators. Through an analysis of the unveiling ceremony, this researcher argues that the Pitt County monument was intended to promote five central tenets of the “Lost Cause� ideology: glorification and romanticization of the Confederacy, white supremacy, male dominance of political and cultural life, preeminence of Southern Christianity, and generational transference of the four previous ideas

    Rapid analysis of iodinated X-ray contrast media in secondary and tertiary treated wastewater by direct injection liquid chromatography-tandem mass spectrometry

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    The iodinated x-ray contrast media (ICM) are the most widely administered intravascular pharmaceuticals and are known to persist in the aquatic environment. A rapid method using direct injection liquid chromatography-tandem mass spectrometry (DI-LC-MS/MS) has been developed to measure eight ICM. These include iopamidol, iothalamic acid, diatrizoic acid, iohexol, iomeprol, iopromide, plus both ioxaglic acid and iodipamide, which have not previously reported in the literature. The LC-MS/MS fragmentation patterns obtained for each of the compounds are discussed and the fragments lost for each transition are identified. Matrix effects in post-RO water, MQ water, tap water and secondary effluent have also been investigated. The DI-LC-MS/MS method was validated on both secondary and tertiary treated wastewater, and applied to samples from an advanced activated sludge wastewater treatment plant (WWTP) and a water recycling facility using microfiltration (MF) and reverse osmosis (RO) in Perth, Western Australia. As well as providing information of the efficacy for RO to remove specific ICM, these results also represent the first values of ICM published in the literature for Australia

    Width Scaling of an Interface Constrained by a Membrane

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    We investigate the shape of a growing interface in the presence of an impenetrable moving membrane. The two distinct geometrical arrangements of the interface and membrane, obtained by placing the membrane behind or ahead of the interface, are not symmetrically related. On the basis of numerical results and an exact calculation, we argue that these two arrangements represent two distinct universality classes for interfacial growth: whilst the well-established Kardar-Parisi-Zhang (KPZ) growth is obtained in the `ahead' arrangement, we find an arrested KPZ growth with a smaller roughness exponent in the `behind' arrangement. This suggests that the surface properties of growing cell membranes and expanding bacterial colonies, for example, are fundamentally distinct.Comment: 6 pages, 6 figures; revised version contains a small amount of additional discussion and the supplementary figures. To appear in Phys. Rev. Let

    Validation of Dual Membrane Treatment for Indirect Potable Reuse

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    The Western Australia's Premier's Collaborative Research Program (PCRP) project 'Characterising Treated Wastewater for Drinking Purposes Following Reverse Osmosis Treatment' commenced in October 2005, to determine the potential risks of replenishing drinking water aquifers with MF/RO treated secondary wastewater from Perth?s wastewater treatment plants. A brief report on the project won the Michael Flynn Award for the best poster paper at Ozwater 10. The results included those published in Water, February 2010, by Rodriguez et al, entitled Efficiency of RO for removal of Chemical Contaminants. Consequently, this version has been drafted to cover the other aspects of the study, principally the identification of suitable indicators which could be used to validate treatment performance

    Valosin-containing protein (VCP)–Adaptor Interactions are Exceptionally Dynamic and Subject to Differential Modulation by a VCP Inhibitor

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    Protein quality control (PQC) plays an important role in stemming neurodegenerative diseases and is essential for the growth of some cancers. Valosin-containing protein (VCP)/p97 plays a pivotal role in multiple PQC pathways by interacting with numerous adaptors that link VCP to specific PQC pathways and substrates and influence the post-translational modification state of substrates. However, our poor understanding of the specificity and architecture of the adaptors, and the dynamic properties of their interactions with VCP hinders our understanding of fundamental features of PQC and how modulation of VCP activity can best be exploited therapeutically. In this study we use multiple mass spectrometry-based proteomic approaches combined with biophysical studies to characterize the interaction of adaptors with VCP. Our results reveal that most VCP-adaptor interactions are characterized by rapid dynamics that in some cases are modulated by the VCP inhibitor NMS873. These findings have significant implications for both the regulation of VCP function and the impact of VCP inhibition on different VCP-adaptor complexes

    Valosin-containing protein (VCP)–Adaptor Interactions are Exceptionally Dynamic and Subject to Differential Modulation by a VCP Inhibitor

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    Protein quality control (PQC) plays an important role in stemming neurodegenerative diseases and is essential for the growth of some cancers. Valosin-containing protein (VCP)/p97 plays a pivotal role in multiple PQC pathways by interacting with numerous adaptors that link VCP to specific PQC pathways and substrates and influence the post-translational modification state of substrates. However, our poor understanding of the specificity and architecture of the adaptors, and the dynamic properties of their interactions with VCP hinders our understanding of fundamental features of PQC and how modulation of VCP activity can best be exploited therapeutically. In this study we use multiple mass spectrometry-based proteomic approaches combined with biophysical studies to characterize the interaction of adaptors with VCP. Our results reveal that most VCP-adaptor interactions are characterized by rapid dynamics that in some cases are modulated by the VCP inhibitor NMS873. These findings have significant implications for both the regulation of VCP function and the impact of VCP inhibition on different VCP-adaptor complexes

    Twenty five years after KLS: A celebration of non-equilibrium statistical mechanics

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    When Lenz proposed a simple model for phase transitions in magnetism, he couldn't have imagined that the "Ising model" was to become a jewel in field of equilibrium statistical mechanics. Its role spans the spectrum, from a good pedagogical example to a universality class in critical phenomena. A quarter century ago, Katz, Lebowitz and Spohn found a similar treasure. By introducing a seemingly trivial modification to the Ising lattice gas, they took it into the vast realms of non-equilibrium statistical mechanics. An abundant variety of unexpected behavior emerged and caught many of us by surprise. We present a brief review of some of the new insights garnered and some of the outstanding puzzles, as well as speculate on the model's role in the future of non-equilibrium statistical physics.Comment: 3 figures. Proceedings of 100th Statistical Mechanics Meeting, Rutgers, NJ (December, 2008

    Applications of Field-Theoretic Renormalization Group Methods to Reaction-Diffusion Problems

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    We review the application of field-theoretic renormalization group (RG) methods to the study of fluctuations in reaction-diffusion problems. We first investigate the physical origin of universality in these systems, before comparing RG methods to other available analytic techniques, including exact solutions and Smoluchowski-type approximations. Starting from the microscopic reaction-diffusion master equation, we then pedagogically detail the mapping to a field theory for the single-species reaction k A -> l A (l < k). We employ this particularly simple but non-trivial system to introduce the field-theoretic RG tools, including the diagrammatic perturbation expansion, renormalization, and Callan-Symanzik RG flow equation. We demonstrate how these techniques permit the calculation of universal quantities such as density decay exponents and amplitudes via perturbative eps = d_c - d expansions with respect to the upper critical dimension d_c. With these basics established, we then provide an overview of more sophisticated applications to multiple species reactions, disorder effects, L'evy flights, persistence problems, and the influence of spatial boundaries. We also analyze field-theoretic approaches to nonequilibrium phase transitions separating active from absorbing states. We focus particularly on the generic directed percolation universality class, as well as on the most prominent exception to this class: even-offspring branching and annihilating random walks. Finally, we summarize the state of the field and present our perspective on outstanding problems for the future.Comment: 10 figures include

    Maintenance of order in a moving strong condensate

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    We investigate the conditions under which a moving condensate may exist in a driven mass transport system. Our paradigm is a minimal mass transport model in which n−1n-1 particles move simultaneously from a site containing n>1n>1 particles to the neighbouring site in a preferred direction. In the spirit of a Zero-Range process the rate u(n)u(n) of this move depends only on the occupation of the departure site. We study a hopping rate u(n)=1+b/nαu(n) = 1 + b/n^\alpha numerically and find a moving strong condensate phase for b>bc(α)b > b_c(\alpha) for all α>0\alpha >0. This phase is characterised by a condensate that moves through the system and comprises a fraction of the system's mass that tends to unity. The mass lost by the condensate as it moves is constantly replenished from the trailing tail of low occupancy sites that collectively comprise a vanishing fraction of the mass. We formulate an approximate analytical treatment of the model that allows a reasonable estimate of bc(α)b_c(\alpha) to be obtained. We show numerically (for α=1\alpha=1) that the transition is of mixed order, exhibiting exhibiting a discontinuity in the order parameter as well as a diverging length scale as b↘bcb\searrow b_c.Comment: 15 figs, 20 page

    Vms1 and ANKZF1 peptidyl-tRNA hydrolases release nascent chains from stalled ribosomes

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    Ribosomal surveillance pathways scan for ribosomes that are transiently paused or terminally stalled owing to structural elements in mRNAs or nascent chain sequences. Some stalls in budding yeast are sensed by the GTPase Hbs1, which loads Dom34, a catalytically inactive member of the archaeo-eukaryotic release factor 1 superfamily. Hbs1–Dom34 and the ATPase Rli1 dissociate stalled ribosomes into 40S and 60S subunits. However, the 60S subunits retain the peptidyl-tRNA nascent chains, which recruit the ribosome quality control complex that consists of Rqc1–Rqc2–Ltn1–Cdc48–Ufd1–Npl4. Nascent chains ubiquitylated by the E3 ubiquitin ligase Ltn1 are extracted from the 60S subunit by the ATPase Cdc48–Ufd1–Npl4 and presented to the 26S proteasome for degradation. Failure to degrade the nascent chains leads to protein aggregation and proteotoxic stress in yeast and neurodegeneration in mice. Despite intensive investigations on the ribosome quality control pathway, it is not known how the tRNA is hydrolysed from the ubiquitylated nascent chain before its degradation. Here we show that the Cdc48 adaptor Vms1 is a peptidyl-tRNA hydrolase. Similar to classical eukaryotic release factor 1, Vms1 activity is dependent on a conserved catalytic glutamine. Evolutionary analysis indicates that yeast Vms1 is the founding member of a clade of eukaryotic release factor 1 homologues that we designate the Vms1-like release factor 1 clade
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