1,149 research outputs found
On the existence of dyons and dyonic black holes in Einstein-Yang-Mills theory
We study dyonic soliton and black hole solutions of the
Einstein-Yang-Mills equations in asymptotically anti-de Sitter space. We prove
the existence of non-trivial dyonic soliton and black hole solutions in a
neighbourhood of the trivial solution. For these solutions the magnetic gauge
field function has no zeros and we conjecture that at least some of these
non-trivial solutions will be stable. The global existence proof uses local
existence results and a non-linear perturbation argument based on the (Banach
space) implicit function theorem.Comment: 23 pages, 2 figures. Minor revisions; references adde
Characterizing asymptotically anti-de Sitter black holes with abundant stable gauge field hair
In the light of the "no-hair" conjecture, we revisit stable black holes in
su(N) Einstein-Yang-Mills theory with a negative cosmological constant. These
black holes are endowed with copious amounts of gauge field hair, and we
address the question of whether these black holes can be uniquely characterized
by their mass and a set of global non-Abelian charges defined far from the
black hole. For the su(3) case, we present numerical evidence that stable black
hole configurations are fixed by their mass and two non-Abelian charges. For
general N, we argue that the mass and N-1 non-Abelian charges are sufficient to
characterize large stable black holes, in keeping with the spirit of the
"no-hair" conjecture, at least in the limit of very large magnitude
cosmological constant and for a subspace containing stable black holes (and
possibly some unstable ones as well).Comment: 33 pages, 13 figures, minor change
Motherhood as Contested Ideological Terrain: Essentialist and Queer Discourses of Motherhood at Play in FemaleâFemale Co-mothersâ Talk
Framed by relational dialectics theory (Baxter), this investigation considered the meaning(s) of motherhood in femaleâfemale co-motherhood. Analysis identified two competing discourses: (1) discourse of essential motherhood (DEM) and (2) discourse of queer motherhood (DQM). Speakersâ invocation of the DEM reinscribes the mainstream US cultural discourse that children can have only one authentic (i.e., biological) mother, whereas invocation of the DQM denaturalizes the DEMâs presumptions of authentic motherhood as biological, interrupts monomaternalism, destabilizes the patriarch, and troubles the equation of biological with moral motherhood. Whereas interpenetrations of the DEM and DQM were typically sites of adversarial discursive struggle, in a few instances, the DEM and DQM rose above their antagonistic relationship, combining to create new meanings of motherhood
âVaccine Passportsâ may backfire: findings from a cross-sectional study in the UK and Israel on willingness to get vaccinated against COVID-19
Domestic âvaccine passportsâ are being implemented across the world as a way of in-creasing vaccinated peopleâs freedom of movement and to encourage vaccination. However, these vaccine passports may affect peopleâs vaccination decisions in unintended and undesirable ways. This cross-sectional study investigated whether peopleâs willingness and motivation to get vaccinated relate to their psychological needs (autonomy, competence and relatedness), and how vaccine passports might affect these needs. Across two countries and 1358 participants, we found that need frustrationâparticularly autonomy frustrationâwas associated with lower willingness to get vaccinated and with a shift from self-determined to external motivation. In Israel (a country with vaccine passports), people reported greater autonomy frustration than in the UK (a country without vaccine passports). Our findings suggest that control measures, such as domestic vaccine passports, may have detrimental effects on peopleâs autonomy, motivation, and willingness to get vaccinated. Policies should strive to achieve a highly vaccinated population by supporting individualsâ autonomous motivation to get vaccinated and using messages of autonomy and relatedness, rather than applying pressure and external controls
Serum Salicylate Levels and Risk of Recurrent Colorectal Adenomas
Intake of aspirin is associated with reduction in risk of colorectal adenoma and carcinoma. Some plants contain salicylates, and individuals not taking aspirin may have measurable salicylate levels. However, the association between serum salicylate level and recurrence of adenoma in non-users of aspirin has not been studied
Theoretical studies of the historical development of the accounting discipline: a review and evidence
Many existing studies of the development of accounting thought have either been atheoretical or have adopted Kuhn's model of scientific growth. The limitations of this 35-year-old model are discussed. Four different general neo-Kuhnian models of scholarly knowledge development are reviewed and compared with reference to an analytical matrix. The models are found to be mutually consistent, with each focusing on a different aspect of development. A composite model is proposed. Based on a hand-crafted database, author co-citation analysis is used to map empirically the entire literature structure of the accounting discipline during two consecutive time periods, 1972â81 and 1982â90. The changing structure of the accounting literature is interpreted using the proposed composite model of scholarly knowledge development
C-reactive Protein and Risk of Colorectal Adenomas or Serrated Polyps: A Prospective Study
Serum C-reactive protein (CRP) is a sensitive marker of systemic inflammation. Since there is a well-recognized relationship between local inflammation and colorectal cancer, we aimed to evaluate whether serum CRP levels were associated with the occurrence of colorectal adenomas and serrated polyps using data from a large adenoma prevention trial. 930 participants with a history of colorectal adenomas were enrolled in a randomized trial of calcium supplementation (1200 mg/day) for the prevention of colorectal adenomas. Outcomes in this analysis are metachronous adenomas (and advanced neoplasms specifically), and serrated polyps at follow-up colonoscopy. High sensitivity CRP levels were measured 1 year following baseline colonoscopy. Multivariate analysis was performed to estimate risk ratios (RR) using Poisson regression, controlling for potential confounders. We measured serum CRP levels in 689 participants(mean CRP 3.62mg/L ± 5.72). There was no difference in CRP levels with respect to calcium vs. placebo treatment assignment (p=0.99). After adjustment for potential confounders, we found no association between CRP level and risk of recurrent adenoma or advanced lesion (Quartile 4 vs. Quartile 1: RR (95% CI) = 0.99 (0.73, 1.34) and 0.92 (0.49, 1.75) respectively). Similarly, no association was seen between CRP levels and riskof serrated polypsor proximal serrated polyps(Quartile 4 vs. Quartile 1: RR (95% CI) = 1.32 (0.85, 2.03) and 1.19 (0.54, 2.58) respectively. In conclusion, this large prospective colorectal adenoma chemoprevention study found no significant relationship between CRP levels and occurrence of adenomas, advanced neoplasms, or serrated polyps
Evaluation of Bone Marrow Adipose Tissue and Bone Mineralization on Broiler Chickens Affected by Wooden Breast Myopathy
In humans, alterations in bone metabolism have been associated with myopathies. We postulate the hypothesis that perhaps similar pathologies can also be associated in modern chickens. Hence, this study aimed to assess the fat infiltration in bone marrow and its repercussion on broiler chicken affected by Wooden Breast (WB) myopathy. Ten Cobb 500 live birds with extreme rigidity of the Pectoralis major (PM) muscle were selected as WB affected chickens by physical examination of the muscle at 49 days of age, whereas ten chickens healthy with no physical signs of hardness in the breast muscle were considered to be unaffected. Macroscopic lesions in affected chickens included areas of firm and inflamed muscle with pale appearance, hemorrhaging, and viscous exudate on the surface. Bone marrow and sections of the PM muscle were collected and analyzed for light microscopy. Additionally, transmission electron microscopy was conducted in affected or unaffected muscle. Chickens affected with WB showed significant reductions (P < 0.05) in femur diameter, calcium, and phosphorous percentage but increased breast weight, compression force and filet thickness when compared with non-affected chickens. Interestingly, bone marrow from WB chicken had subjectively, more abundant infiltration of adipose tissue, when compared with non-affected chickens. Histology of the Pectoralis major of birds with WB showed abundant infiltration of adipose tissue, muscle fibers degeneration with necrosis and infiltration of heterophils and mononuclear cells, connective tissue proliferation, and vasculitis. Ultrastructural changes of WB muscle revealed lack definition of bands in muscle tissue, or any normal ultrastructural anatomy such as myofibrils. The endomysium components were necrotic, and in some areas, the endomysium was notable only as a string of necrotic tissue between degraded myofibrils. The fascia appeared hypertrophied, with large areas of necrosis and myofiber without structural identity with degraded mitochondria adjacent to the disrupted muscle tissue. As far as we know, this is the first study that describes a subjective increase in adipose tissue in the bone marrow of chickens affected with WB when compared with non-affected chickens, and reduced bone mineralization
Navigating to new frontiers in behavioral neuroscience: traditional neuropsychological tests predict human performance on a rodent-inspired radial-arm maze
We constructed an 11-arm, walk-through, human radial-arm maze (HRAM) as a translational instrument to compare existing methodology in the areas of rodent and human learning and memory research. The HRAM, utilized here, serves as an intermediary test between the classic rat radial-arm maze (RAM) and standard human neuropsychological and cognitive tests. We show that the HRAM is a useful instrument to examine working memory ability, explore the relationships between rodent and human memory and cognition models, and evaluate factors that contribute to human navigational ability. One-hundred-and-fifty-seven participants were tested on the HRAM, and scores were compared to performance on a standard cognitive battery focused on episodic memory, working memory capacity, and visuospatial ability. We found that errors on the HRAM increased as working memory demand became elevated, similar to the pattern typically seen in rodents, and that for this task, performance appears similar to Miller's classic description of a processing-inclusive human working memory capacity of 7 ± 2 items. Regression analysis revealed that measures of working memory capacity and visuospatial ability accounted for a large proportion of variance in HRAM scores, while measures of episodic memory and general intelligence did not serve as significant predictors of HRAM performance. We present the HRAM as a novel instrument for measuring navigational behavior in humans, as is traditionally done in basic science studies evaluating rodent learning and memory, thus providing a useful tool to help connect and translate between human and rodent models of cognitive functioning
Human astrocytes and microglia show augmented ingestion of synapses in Alzheimer's disease via MFG-E8
Synapse loss correlates with cognitive decline in Alzheimer's disease (AD). Data from mouse models suggests microglia are important for synapse degeneration, but direct human evidence for any glial involvement in synapse removal in human AD remains to be established. Here we observe astrocytes and microglia from human brains contain greater amounts of synaptic protein in AD compared with non-disease controls, and that proximity to amyloid-ÎČ plaques and the APOE4 risk gene exacerbate this effect. In culture, mouse and human astrocytes and primary mouse and human microglia phagocytose AD patient-derived synapses more than synapses from controls. Inhibiting interactions of MFG-E8 rescues the elevated engulfment of AD synapses by astrocytes and microglia without affecting control synapse uptake. Thus, AD promotes increased synapse ingestion by human glial cells at least in part via an MFG-E8 opsonophagocytic mechanism with potential for targeted therapeutic manipulation.</p
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