Why Quantum Theory is Possibly Wrong

Quantum theory is a tremendously successful physical theory, but nevertheless suffers from two serious problems: the measurement problem and the problem of interpretational underdetermination. The latter, however, is largely overlooked as a genuine problem of its own. Both problems concern the doctrine of realism, but pull, quite curiously, into opposite directions. The measurement problem can be captured such that due to scientific realism about quantum theory common sense anti-realism follows, while theory underdetermination usually counts as an argument against scientific realism. I will also consider the more refined distinctions of ontic and epistemic realism and demonstrate that quantum theory in its most viable interpretations conflicts with at least one of the various realism claims. A way out of the conundrum is to come to the bold conclusion that quantum theory is, possibly, wrong (in the realist sense)

LEAP2 changes with body mass and food intake in humans and mice

Acyl-ghrelin administration increases food intake, body weight, and blood glucose. In contrast, mice lacking ghrelin or ghrelin receptors (GHSRs) exhibit life-threatening hypoglycemia during starvation-like conditions but do not consistently exhibit overt metabolic phenotypes when given ad libitum food access. These results, and findings of ghrelin resistance in obese states, imply nutritional state-dependence of ghrelin’s metabolic actions. Here, we hypothesized that LEAP2 (liver enriched antimicrobial peptide-2), a recently-characterized endogenous GHSR antagonist, blunts ghrelin action during obese states and post-prandially. To test this hypothesis, we determined changes in plasma LEAP2 and acyl-ghrelin due to fasting, eating, obesity, Roux-en-Y gastric bypass (RYGB), vertical sleeve gastrectomy (VSG), oral glucose administration, and type 1 diabetes mellitus (T1DM) using humans and/or mice. Our results suggest that plasma LEAP2 is regulated by metabolic status: its levels increase with body mass and blood glucose, and decrease with fasting, RYGB, and in post-prandial states following VSG. These changes were mostly opposite to those of acyl-ghrelin. Furthermore, using electrophysiology, we showed that LEAP2 both hyperpolarizes and prevents acyl-ghrelin from activating arcuate NPY neurons. We predict that the plasma LEAP2:acyl-ghrelin molar ratio may be a key determinant modulating acyl-ghrelin activity in response to body mass, feeding status, and blood glucose

Pseudospin symmetry as a relativistic dynamical symmetry in the nucleus

Pseudospin symmetry in nuclei is investigated by solving the Dirac equation with Woods-Saxon scalar and vector radial potentials, and studying the correlation of the energy splittings of pseudospin partners with the nuclear potential parameters. The pseudospin interaction is related to a pseudospin-orbit term that arises in a Schroedinger-like equation for the lower component of the Dirac spinor. We show that the contribution from this term to the energy splittings of pseudospin partners is large. The near pseudospin degeneracy results from a significant cancelation among the different terms in that equation, manifesting the dynamical character of this symmetry in the nucleus. We analyze the isospin dependence of the pseudospin symmetry and find that its dynamical character is behind the different pseudospin splittings observed in neutron and proton spectra of nuclei.Comment: 13 pages, 9 figures, uses REVTeX4 macro

Ground state and elementary excitations of single and binary Bose-Einstein condensates of trapped dipolar gases

We analyze the ground-state properties and the excitation spectrum of Bose-Einstein condensates of trapped dipolar particles. First, we consider the case of a single-component polarized dipolar gas. For this case we discuss the influence of the trapping geometry on the stability of the condensate as well as the effects of the dipole-dipole interaction on the excitation spectrum. We discuss also the ground state and excitations of a gas composed of two antiparallel dipolar components.Comment: 12 pages, 9 eps figures, final versio

Spin-orbit splittings in heavy-light mesons and Dirac equation

The spin-orbit splitting in heavy-light mesons is seen to be suppressed experimentally. It is shown that it can be understood qualitatively in the frame work of Dirac theory. An alternative derivation of a relativistic dynamical symmetry for the Dirac Hamiltonian, which suppresses spin orbit splitting, is also given. However it is shown that such a symmetry is not needed since the spin-orbit splitting in Dirac theory with Coulomb like potential (as is the case for the one gluon exchange potential in pQCD) is small anyway.Comment: 9 pages, 1 fi

Explaining the social gradient in smoking and cessation: the peril and promise of social mobility

Smoking in high-income countries is now concentrated in poor communities whose relatively high smoking prevalence is explained by greater uptake but above all by lower quit rates. Whilst a number of barriers to smoking cessation have been identified, this is the first paper to situate cessation itself as a classed and cultural practice. Drawing on ethnographic research carried out in a working class community in the North of England between 2012 and 2015, I theorise smoking cessation as a symbolic practice in relation to the affective experience of class and social mobility. I show that ambivalence about upward mobility as separation and loss translated into ambivalence about smoking cessation. The reason for this was that the social gradient in smoking operated dynamically at the level of the individual life course i.e. smoking cessation followed upward mobility. A serious health problem was an appropriate reason to quit but older women continued to smoke despite serious health problems. This was linked to historical gender roles leading to women placing a low priority on their own health as well as the intergenerational reproduction of smoking through close affective links with smoking parents

Fitting the integrated Spectral Energy Distributions of Galaxies

Fitting the spectral energy distributions (SEDs) of galaxies is an almost universally used technique that has matured significantly in the last decade. Model predictions and fitting procedures have improved significantly over this time, attempting to keep up with the vastly increased volume and quality of available data. We review here the field of SED fitting, describing the modelling of ultraviolet to infrared galaxy SEDs, the creation of multiwavelength data sets, and the methods used to fit model SEDs to observed galaxy data sets. We touch upon the achievements and challenges in the major ingredients of SED fitting, with a special emphasis on describing the interplay between the quality of the available data, the quality of the available models, and the best fitting technique to use in order to obtain a realistic measurement as well as realistic uncertainties. We conclude that SED fitting can be used effectively to derive a range of physical properties of galaxies, such as redshift, stellar masses, star formation rates, dust masses, and metallicities, with care taken not to over-interpret the available data. Yet there still exist many issues such as estimating the age of the oldest stars in a galaxy, finer details ofdust properties and dust-star geometry, and the influences of poorly understood, luminous stellar types and phases. The challenge for the coming years will be to improve both the models and the observational data sets to resolve these uncertainties. The present review will be made available on an interactive, moderated web page (sedfitting.org), where the community can access and change the text. The intention is to expand the text and keep it up to date over the coming years.Comment: 54 pages, 26 figures, Accepted for publication in Astrophysics & Space Scienc

Magnetic Reconnection in Extreme Astrophysical Environments

Magnetic reconnection is a basic plasma process of dramatic rearrangement of magnetic topology, often leading to a violent release of magnetic energy. It is important in magnetic fusion and in space and solar physics --- areas that have so far provided the context for most of reconnection research. Importantly, these environments consist just of electrons and ions and the dissipated energy always stays with the plasma. In contrast, in this paper I introduce a new direction of research, motivated by several important problems in high-energy astrophysics --- reconnection in high energy density (HED) radiative plasmas, where radiation pressure and radiative cooling become dominant factors in the pressure and energy balance. I identify the key processes distinguishing HED reconnection: special-relativistic effects; radiative effects (radiative cooling, radiation pressure, and Compton resistivity); and, at the most extreme end, QED effects, including pair creation. I then discuss the main astrophysical applications --- situations with magnetar-strength fields (exceeding the quantum critical field of about 4 x 10^13 G): giant SGR flares and magnetically-powered central engines and jets of GRBs. Here, magnetic energy density is so high that its dissipation heats the plasma to MeV temperatures. Electron-positron pairs are then copiously produced, making the reconnection layer highly collisional and dressing it in a thick pair coat that traps radiation. The pressure is dominated by radiation and pairs. Yet, radiation diffusion across the layer may be faster than the global Alfv\'en transit time; then, radiative cooling governs the thermodynamics and reconnection becomes a radiative transfer problem, greatly affected by the ultra-strong magnetic field. This overall picture is very different from our traditional picture of reconnection and thus represents a new frontier in reconnection research.Comment: Accepted to Space Science Reviews (special issue on magnetic reconnection). Article is based on an invited review talk at the Yosemite-2010 Workshop on Magnetic Reconnection (Yosemite NP, CA, USA; February 8-12, 2010). 30 pages, no figure

Accuracy of emergency medical service telephone triage of need for an ambulance response in suspected COVID-19 : an observational cohort study

Objective: To assess accuracy of emergency medical service (EMS) telephone triage in identifying patients who need an EMS response and identify factors which affect triage accuracy. Design: Observational cohort study. Setting Emergency telephone triage provided by Yorkshire Ambulance Service (YAS) National Health Service (NHS) Trust. Participants: 12 653 adults who contacted EMS telephone triage services provided by YAS between 2 April 2020 and 29 June 2020 assessed by COVID-19 telephone triage pathways were included. Outcome: Accuracy of call handler decision to dispatch an ambulance was assessed in terms of death or need for organ support at 30 days from first contact with the telephone triage service. Results: Callers contacting EMS dispatch services had an 11.1% (1405/12 653) risk of death or needing organ support. In total, 2000/12 653 (16%) of callers did not receive an emergency response and they had a 70/2000 (3.5%) risk of death or organ support. Ambulances were dispatched to 4230 callers (33.4%) who were not conveyed to hospital and did not deteriorate. Multivariable modelling found variables of older age (1 year increase, OR: 1.05, 95% CI: 1.04 to 1.05) and presence of pre-existing respiratory disease (OR: 1.35, 95% CI: 1.13 to 1.60) to be predictors of false positive triage. Conclusion: Telephone triage can reduce ambulance responses but, with low specificity. A small but significant proportion of patients who do not receive an initial emergency response deteriorated. Research to improve accuracy of EMS telephone triage is needed and, due to limitations of routinely collected data, this is likely to require prospective data collection

Accuracy of telephone triage for predicting adverse outcomes in suspected COVID-19: an observational cohort study

Objective: To assess accuracy of telephone triage in identifying need for emergency care among those with suspected COVID-19 infection and identify factors which affect triage accuracy. Design: Observational cohort study. Setting: Community telephone triage provided in the UK by Yorkshire Ambulance Service NHS Trust (YAS). Participants: 40 261 adults who contacted National Health Service (NHS) 111 telephone triage services provided by YAS between 18 March 2020 and 29 June 2020 with symptoms indicating COVID-19 infection were linked to Office for National Statistics death registrations and healthcare data collected by NHS Digital. Outcome: Accuracy of triage disposition was assessed in terms of death or need for organ support up to 30 days from first contact. Results: Callers had a 3% (1200/40 261) risk of serious adverse outcomes (death or organ support). Telephone triage recommended self-care or non-urgent assessment for 60% (24 335/40 261), with a 1.3% (310/24 335) risk of adverse outcomes. Telephone triage had 74.2% sensitivity (95% CI: 71.6 to 76.6%) and 61.5% specificity (95% CI: 61% to 62%) for the primary outcome. Multivariable analysis suggested respiratory comorbidities may be overappreciated, and diabetes underappreciated as predictors of deterioration. Repeat contact with triage service appears to be an important under-recognised predictor of deterioration with 2 contacts (OR 1.77, 95% CI: 1.14 to 2.75) and 3 or more contacts (OR 4.02, 95% CI: 1.68 to 9.65) associated with false negative triage. Conclusion: Patients advised to self-care or receive non-urgent clinical assessment had a small but non-negligible risk of serious clinical deterioration. Repeat contact with telephone services needs recognition as an important predictor of subsequent adverse outcomes