256 research outputs found
Charged Condensate and Helium Dwarf Stars
White dwarf stars composed of carbon, oxygen or heavier elements are expected
to crystallize as they cool down below certain temperatures. Yet, simple
arguments suggest that the helium white dwarf cores may not solidify, mostly
because of zero-point oscillations of the helium ions that would dissolve the
crystalline structure. We argue that the interior of the helium dwarfs may
instead form a macroscopic quantum state in which the charged helium-4 nuclei
are in a Bose-Einstein condensate, while the relativistic electrons form a
neutralizing degenerate Fermi liquid. We discuss the electric charge screening,
and the spectrum of this substance, showing that the bosonic long-wavelength
fluctuations exhibit a mass gap. Hence, there is a suppression at low
temperatures of the boson contribution to the specific heat -- the latter being
dominated by the specific heat of the electrons near the Fermi surface. This
state of matter may have observational signatures.Comment: 10 pages; v2: to appear in JCAP, brief comments and section titles
added, typos correcte
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The Case for Thoughtful Prescribing of Proton Pump Inhibitors in Infants.
Phase Transitions of Charged Scalars at Finite Temperature and Chemical Potential
We calculate the grand canonical partition function at the one-loop level for
scalar quantum electrodynamics at finite temperature and chemical potential. A
classical background charge density with a charge opposite that of the scalars
ensures the neutrality of the system. For low density systems we find evidence
of a first order phase transition. We find upper and lower bounds on the
transition temperature below which the charged scalars form a condensate. A
first order phase transition may have consequences for helium-core white dwarf
stars in which it has been argued that such a condensate of charged helium-4
nuclei could exist.Comment: 20 pages, 3 figures. Version accepted for publication in JHE
An absent presence: Separated child migrantsâ caring practices and the fortified neoliberal state
This paper explores the ambivalent positioning of separated child migrants in the UK with a focus on the care that they provide for each other. Drawing on interview data with state and non-state adult stakeholders involved in the immigration-welfare nexus, we consider how childrenâs care practices are viewed and represented. We argue that separated childrenâs caring practices assume an absent presence in the discourses mobilised by these actors: either difficult to articulate or represented in negative and morally-laden terms, reflective of the UKâs 'hostile environment' towards migrants and advanced capitalist constructions of childhood. Such an examination sheds light on the complex state attempts to manage the care and migration regimes, and the way that care can serve as a way of making and marking inclusions and exclusions. Here we emphasise the political consequences for separated child migrants in an age of neoliberal state retrenchment from public provision of care and rising xenophobic nationalism
On Non-Linear Actions for Massive Gravity
In this work we present a systematic construction of the potentially
ghost-free non-linear massive gravity actions. The most general action can be
regarded as a 2-parameter deformation of a minimal massive action. Further
extensions vanish in 4 dimensions. The general mass term is constructed in
terms of a "deformed" determinant from which this property can clearly be seen.
In addition, our formulation identifies non-dynamical terms that appear in
previous constructions and which do not contribute to the equations of motion.
We elaborate on the formal structure of these theories as well as some of their
implications.Comment: v3: 22 pages, minor comments added, version to appear in JHE
Genetic Diversity of Near Genome-Wide Hepatitis C Virus Sequences during Chronic Infection: Evidence for Protein Structural Conservation Over Time
Infection with hepatitis C virus (HCV) is one of the leading causes of chronic hepatitis, liver cirrhosis and end-stage liver disease worldwide. The genetics of HCV infection in humans and the disease course of chronic hepatitis C are both remarkably variable. Although the response to interferon treatment is largely dependent on HCV genotypes, whether or not a relationship exists between HCV genome variability and clinical course of hepatitis C disease still remains unknown. To more thoroughly understand HCV genome evolution over time in association with disease course, near genome-wide HCV genomes present in 9 chronically infected participants over 83 total study years were sequenced. Overall, within HCV genomes, the number of synonymous substitutions per synonymous site (dS) significantly exceeded the number of non-synonymous substitutions per site (dN). Although both dS and dN significantly increased with duration of chronic infection, there was a highly significant decrease in dN/dS ratio in HCV genomes over time. These results indicate that purifying selection acted to conserve viral protein structure despite persistence of high level of nucleotide mutagenesis inherent to HCV replication. Based on liver biopsy fibrosis scores, HCV genomes from participants with advanced fibrosis had significantly greater dS values and lower dN/dS ratios compared to participants with mild liver disease. Over time, viral genomes from participants with mild disease had significantly greater annual changes in dN, along with higher dN/dS ratios, compared to participants with advanced fibrosis. Yearly amino acid variations in the HCV p7, NS2, NS3 and NS5B genes were all significantly lower in participants with severe versus mild disease, suggesting possible pathogenic importance of protein structural conservation for these viral gene products
Vortex Structure in Charged Condensate
We study magnetic fields in the charged condensate that we have previously
argued should be present in helium-core white dwarf stars. We show that below a
certain critical value the magnetic field is entirely expelled from the
condensate, while for larger values it penetrates the condensate within
flux-tubes that are similar to Abrikosov vortex lines; yet higher fields lead
to the disruption of the condensate. We find the solution for the vortex lines
in both relativistic and nonrelativistic theories that exhibit the charged
condensation. We calculate the energy density of the vortex solution and the
values of the critical magnetic fields. The minimum magnetic field required for
vortices to penetrate the helium white dwarf cores ranges from roughly 10^7 to
10^9 Gauss. Fields of this strength have been observed in white dwarfs. We also
calculate the London magnetic field due to the rotation of a dwarf star and
show that its value is rather small.Comment: 23 page
Pain outcomes in patients with bone metastases from advanced cancer: assessment and management with bone-targeting agents
Bone metastases in advanced cancer frequently cause painful complications that impair patient physical activity and negatively affect quality of life. Pain is often underreported and poorly managed in these patients. The most commonly used pain assessment instruments are visual analogue scales, a single-item measure, and the Brief Pain Inventory Questionnaire-Short Form. The World Health Organization analgesic ladder and the Analgesic Quantification Algorithm are used to evaluate analgesic use. Bone-targeting agents, such as denosumab or bisphosphonates, prevent skeletal complications (i.e., radiation to bone, pathologic fractures, surgery to bone, and spinal cord compression) and can also improve pain outcomes in patients with metastatic bone disease. We have reviewed pain outcomes and analgesic use and reported pain data from an integrated analysis of randomized controlled studies of denosumab versus the bisphosphonate zoledronic acid (ZA) in patients with bone metastases from advanced solid tumors. Intravenous bisphosphonates improved pain outcomes in patients with bone metastases from solid tumors. Compared with ZA, denosumab further prevented pain worsening and delayed the need for treatment with strong opioids. In patients with no or mild pain at baseline, denosumab reduced the risk of increasing pain severity and delayed pain worsening along with the time to increased pain interference compared with ZA, suggesting that use of denosumab (with appropriate calcium and vitamin D supplementation) before patients develop bone pain may improve outcomes. These data also support the use of validated pain assessments to optimize treatment and reduce the burden of pain associated with metastatic bone disease
Did people really drink bleach to prevent COVID-19? A guide for protecting survey data against problematic respondents
Survey respondents who are non-attentive, respond randomly, or misrepresent who they are can impact the outcomes of surveys. Prior findings reported by the CDC have suggested that people engaged in highly dangerous cleaning practices during the COVID-19 pandemic, including ingesting household cleaners such as bleach. In our attempts to replicate the CDCâs results, we found that 100% of reported ingestion of household cleaners are made by problematic respondents. Once inattentive, acquiescent, and careless respondents are removed from the sample, we find no evidence that people ingested cleaning products to prevent a COVID-19 infection. These findings have important implications for public health and medical survey research, as well as for best practices for avoiding problematic respondents in all survey research conducted online
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