649 research outputs found
The Effects of Federal Spending on Earnings Change in Appalachia
In this paper we investigate the effects of federal spending on earnings change in Appalachian counties during the 1983-88 recovery and 1989-92 recession. Specifically, we explore the effects of federal spending from grants/research, procurement, salary/wages and defense. The analysis controls for key concepts in the human ecology and new urban sociology. The dependent variables are earnings change for each business cycle from a shift-share analysis, which decomposes county earnings change into that from nationally declining industries. The analysis shows that federal spending has no effect on earnings change, when it is considered as an aggregate measure. However, when federal spending is reclassified into the four categories, spending for grants/research has a positive effect on both measures of earnings change in the 1982-88 recovery. Moreover, the effects of grants/research spending are dependent upon the education level of the county population. However, education by grants/research interaction effect is specific to nonmetro counties in Appalachia. Implications for future research are discussed
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
Aesthetic responses to urban greenway trail corridors: Implications for sustainable development in tourism and recreation settings
Urban greenway trails are emerging as potential tourist attractions in cities and are well recognized for their recreation opportunities in general. The study presented an opportunity to expand the scope of aesthetic response research into the realm of urban greenway trails. The concept of likability (Nasar, 1998) was used as a guiding concept in the study. In order to gather data for the study, a web-based virtual tour was developed and implemented. Treatments were assigned to 6 groups that viewed two urban greenway trail corridors. Each trail had three treatments including the existing trail condition, a manipulated trail condition, and a reverse in direction of the existing trail condition. Analyses were conducted to 1) identify dimensions of aesthetic responses, 2) examine relationships between cognitive evaluation, affective response, trail characteristics, and likability, and 3) evaluate specific greenway trail characteristics and their relationships to the trail experience. Results indicated five aesthetic dimensions of the greenway trail corridors. The cognitive dimensions were maintenance, distinctiveness, and naturalness and the affective dimensions were pleasantness and arousal. Pleasantness and distinctiveness were the strongest predictors of likability in urban greenway trails. In terms of greenway trail characteristics, six of eight specific characteristics had predictive value in relation to how inviting the virtual trail was to the viewer. Finally, several greenway trail characteristics had significant influences on human perception and the likability of trail environments. This study proposed a new way of conceptualizing likability and a model of relationships leading to likability. One of the major implications of this study is to identify a way to improve physical conditions of greenway corridors in urban areas based on aesthetic responses. The study also implied that greenways can encompass natural or man-made features and can be managed and developed as a tourist attraction while providing local opportunities in cities. Aesthetic quality influences perceived quality of life and sense of well-being. Findings of the study can help enhance the aesthetic quality of the greenway trails that can contribute to sustainable development in various tourism and recreation settings
Multisphalerons in the Weinberg-Salam Theory
We construct multisphaleron solutions in the Weinberg-Salam theory. The
multisphaleron solutions carry Chern-Simons charge , where is an
integer, counting the winding of the fields in the azimuthal angle. The
well-known sphaleron has . The multisphalerons possess axial symmetry and
parity reflection symmetry. We vary the Higgs mass and the mixing angle. For
small the energies of the multisphalerons are on the order of times the
energy of the sphaleron and their magnetic dipole moments are on the order of
times the magnetic dipole moment of the sphaleron.Comment: 18 pages, latex, 17 figures in uuencoded postscript files. THU-94/1
Parent-of-origin effects propagate through networks to shape metabolic traits
Parent-of-origin effects are unexpectedly common in complex traits, including metabolic and neurological traits. Parent-of-origin effects can be modified by the environment, but the architecture of these gene-by-environmental effects on phenotypes remains to be unraveled. Previously, quantitative trait loci (QTL) showing context-specific parent-of-origin effects on metabolic traits were mapped in the
Sphalerons in Two Higgs Doublet Theories
We undertake a comprehensive investigation of the properties of the sphaleron
in electroweak theories with two Higgs doublets. We do this in as
model-independent a way as possible: by exploring the physical parameter space
described by the masses and mixing angles of the Higgs particles. If there is a
large split in the masses of the neutral Higgs particles, there can be several
sphaleron solutions, distinguished by their properties under parity and the
behaviour of the Higgs field at the origin. In general, these solutions appear
in parity conjugate pairs and are not spherically symmetric, although the
departure from spherical symmetry is small. Including CP violation in the Higgs
potential can change the energy of the sphaleron by up to 14 percent for a
given set of Higgs masses, with significant implications for the baryogenesis
bound on the mass of the lightest Higgs
Association of Prediabetes and Diabetes With Stroke Symptoms The REasons for Geographic And Racial Differences in Stroke (REGARDS) Study
OBJECTIVE Stroke symptoms among individuals reporting no physician diagnosis of stroke are associated with an increased risk of future stroke. Few studies have assessed whether individuals with diabetes or prediabetes, but no physician diagnosis of stroke, have an increased prevalence of stroke symptoms.
RESEARCH DESIGN AND METHODS This study included 25,696 individuals aged ≥45 years from the REasons for Geographic And Racial Differences in Stroke (REGARDS) study who reported no history of stroke or transient ischemic attack at baseline (2003–2007). Glucose measurements, medication use, and self-reported physician diagnosis were used to categorize participants into diabetes, prediabetes, or normal glycemia groups. The presence of six stroke symptoms was assessed using a validated questionnaire.
RESULTS The prevalence of any stroke symptom was higher among participants with diabetes (22.7%) compared with those with prediabetes (15.6%) or normal glycemia (14.9%). In multivariable models, diabetes was associated with any stroke symptom (prevalence odds ratio [POR] 1.28 [95% CI 1.18–1.39]) and two or more stroke symptoms (1.26 [1.12–1.43]) compared with normal glycemia. In analyses of individual stroke symptoms, diabetes was associated with numbness (1.15 [1.03–1.29]), vision loss (1.52 [1.31–1.76]), half-vision loss (1.54 [1.30–1.84]), and lost ability to understand people (1.34 [1.12–1.61]) after multivariable adjustment. No association was present between prediabetes and stroke symptoms.
CONCLUSIONS In this population-based study, almost one in four individuals with diabetes reported stroke symptoms, which suggests that screening for stroke symptoms in diabetes may be warranted
Citrobacter rodentium Subverts ATP Flux and Cholesterol Homeostasis in Intestinal Epithelial Cells In Vivo.
The intestinal epithelial cells (IECs) that line the gut form a robust line of defense against ingested pathogens. We investigated the impact of infection with the enteric pathogen Citrobacter rodentium on mouse IEC metabolism using global proteomic and targeted metabolomics and lipidomics. The major signatures of the infection were upregulation of the sugar transporter Sglt4, aerobic glycolysis, and production of phosphocreatine, which mobilizes cytosolic energy. In contrast, biogenesis of mitochondrial cardiolipins, essential for ATP production, was inhibited, which coincided with increased levels of mucosal O2 and a reduction in colon-associated anaerobic commensals. In addition, IECs responded to infection by activating Srebp2 and the cholesterol biosynthetic pathway. Unexpectedly, infected IECs also upregulated the cholesterol efflux proteins AbcA1, AbcG8, and ApoA1, resulting in higher levels of fecal cholesterol and a bloom of Proteobacteria. These results suggest that C. rodentium manipulates host metabolism to evade innate immune responses and establish a favorable gut ecosystem
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