Stokes’ phenomenon and the absolutely continuous spectrum of one-dimensional Schrödinger operators

AbstractIt is well known that the Airy functions, Ai(−x−μ) and Bi(−x−μ), form a fundamental set of solutions for the differential equationLu(x)≔−u″(x)−xu(x)=μu(x),0⩽x<∞,μ∈R,and that the spectrum of the associated selfadjoint operator consists of the whole real axis and is purely absolutely continuous for any choice of boundary condition at x=0. Also widely known is the fact that the semi-axis [−μ,∞) is an anti-Stokes’ line for solutions of the differential equation Lu(z)=μu(z),z∈C, for each fixed value of the spectral parameter μ. In this paper, we show that this connection between the existence of anti-Stokes’ lines on the real axis and points of the absolutely continuous spectrum holds under much more general circumstances. Further correlations, relating the Stokes’ phenomenon to subordinacy properties of solutions of Lu=μu at infinity and to the boundary behaviour of the Titchmarsh–Weyl m-function on the real axis, are also deduced

Screw dynamo in a time-dependent pipe flow

The kinematic dynamo problem is investigated for the flow of a conducting fluid in a cylindrical, periodic tube with conducting walls. The methods used are an eigenvalue analysis of the steady regime, and the three-dimensional solution of the time-dependent induction equation. The configuration and parameters considered here are close to those of a dynamo experiment planned in Perm, which will use a torus-shaped channel. We find growth of an initial magnetic field by more than 3 orders of magnitude. Marked field growth can be obtained if the braking time is less than 0.2 s and only one diverter is used in the channel. The structure of the seed field has a strong impact on the field amplification factor. The generation properties can be improved by adding ferromagnetic particles to the fluid in order to increase its relative permeability,but this will not be necessary for the success of the dynamo experiment. For higher magnetic Reynolds numbers, the nontrivial evolution of different magnetic modes limits the value of simple `optimistic' and `pessimistic' estimates.Comment: 10 pages, 12 figure

Effect of photoperiod and host distribution on the horizontal transmission of Isaria fumosorosea (Hypocreales: Cordycipitaceae) in greenhouse whitefly assessed using a novel model bioassay

A model bioassay was used to evaluate the epizootic potential and determine the horizontal transmission efficiency of Isaria fumosorosea Trinidadian strains against Trialeurodes vaporariorum pharate adults under optimum conditions (25±0.5°C, ~100% RH) at two different photoperiods. Untreated pharate adults were arranged on laminated graph paper at different distributions to simulate varying infestation levels on a leaf surface. Four potential hosts were located 7, 14 and 21 mm away from a central sporulating cadaver simulating high, medium and low infestation levels, respectively. Percent hosts colonized were recorded 7, 12, 14 and 21 days post-treatment during a 16- and 24-h photophase. After 21 days, mean percent hosts colonized at the highest, middle and lowest infestation levels were 93 and 100%, 22 and 58%, 25 and 39% under a 16- and 24-h photophase, respectively. From the results, it was concluded that the longer the photophase, the greater the percentage of hosts colonized, and as host distance increased from the central sporulating cadaver, colonization decreased. The use of this novel model bioassay technique is the first attempt to evaluate the epizootic potential and determine the horizontal transmission efficiency of I. fumosorosea Trinidadian strains under optimal environmental conditions at different photoperiods. This bioassay can be used to assess horizontal transmission efficiency for the selection of fungi being considered for commercial biopesticide development

Standard Model baryogenesis through four-fermion operators in braneworlds

We study a new baryogenesis scenario in a class of braneworld models with low fundamental scale, which typically have difficulty with baryogenesis. The scenario is characterized by its minimal nature: the field content is that of the Standard Model and all interactions consistent with the gauge symmetry are admitted. Baryon number is violated via a dimension-6 proton decay operator, suppressed today by the mechanism of quark-lepton separation in extra dimensions; we assume that this operator was unsuppressed in the early Universe due to a time-dependent quark-lepton separation. The source of CP violation is the CKM matrix, in combination with the dimension-6 operators. We find that almost independently of cosmology, sufficient baryogenesis is nearly impossible in such a scenario if the fundamental scale is above 100 TeV, as required by an unsuppressed neutron-antineutron oscillation operator. The only exception producing sufficient baryon asymmetry is a scenario involving out-of-equilibrium c quarks interacting with equilibrium b quarks.Comment: 39 pages, 5 figures v2: typos, presentational changes, references and acknowledgments adde

The spiritual revolution and suicidal ideation: an empirical enquiry among 13- to 15-year-old adolescents in England and Wales

The association between conventional religiosity and suicide inhibition has been well explored and documented since the pioneering work of Durkheim. Commentators like Heelas and Woodhead point to ways in which conventional religiosity is giving way in England and Wales to a range of alternative spiritualities, including renewed interest in paranormal phenomena. Taking a sample of 3095 13- to 15-year-old adolescents, the present study examines the association between suicidal ideation and both conventional religiosity and paranormal beliefs, after controlling for individual differences in sex, age and personality (extraversion, neuroticism and psychoticism). The data demonstrate that, while conventional religiosity is slightly associated with lower levels of suicidal ideation, paranormal beliefs are strongly associated with higher levels of suicidal ideation

Patient Preferences for Discussing and Acting on Health-Related Needs in Primary Care

Background: Addressing social needs, health behaviors, and mental health may help patients more than traditional medical care. However, these root causes of poor health are difficult to address and the role of primary care is unclear. This qualitative study assesses patient?s willingness and motivations to discuss and accept assistance for these needs from their primary care team. Methods: In July and August of 2020, semi-structured virtual interviews were conducted with family medicine patients (n=6) and residents of low resource neighborhoods (n=11) in Richmond, Virginia. Interviews were conducted over Zoom. We conducted a qualitative analysis of patient and resident interview transcripts. A rapid qualitative analysis approach and immersion-crystallization processes were used to identify themes and categories. Results: Interviewees reported varying degrees of comfort discussing topics with their health care team. They were less comfortable discussing needs they considered outside the realm of "traditional primary care" including finances, transportation, and housing, but interviewees expressed willingness to discuss these needs under certain conditions. Important factors were a strong patient-clinician relationship to create a trusted and safe space for discussion, adequate time for discussion during visits, communication of practices' ability to provide resources to help patients, and ensuring appropriate high quality referrals. Conclusions: Primary care provides opportunity for identifying and addressing needs that adversely impact health. Some needs are more sensitive for patients to work with their care team on, though, there was willingness to work on any need when a strong provider relationship and clinic structure for providing support were in place. This study highlights critical care delivery factors which may be used to enhance patient comfort accepting support for their needs and ultimately improve clinical care and chronic disease management

Aharonov-Bohm Physics with Spin II: Spin-Flip Effects in Two-dimensional Ballistic Systems

We study spin effects in the magneto-conductance of ballistic mesoscopic systems subject to inhomogeneous magnetic fields. We present a numerical approach to the spin-dependent Landauer conductance which generalizes recursive Green function techniques to the case with spin. Based on this method we address spin-flip effects in quantum transport of spin-polarized and -unpolarized electrons through quantum wires and various two-dimensional Aharonov-Bohm geometries. In particular, we investigate the range of validity of a spin switch mechanism recently found which allows for controlling spins indirectly via Aharonov-Bohm fluxes. Our numerical results are compared to a transfer-matrix model for one-dimensional ring structures presented in the first paper (Hentschel et al., submitted to Phys. Rev. B) of this series.Comment: 29 pages, 15 figures. Second part of a series of two article

Maximal Neutrino Mixing from a Minimal Flavor Symmetry

We study a number of models, based on a non-Abelian discrete group, that successfully reproduce the simple and predictive Yukawa textures usually associated with U(2) theories of flavor. These models allow for solutions to the solar and atmospheric neutrino problems that do not require altering successful predictions for the charged fermions or introducing sterile neutrinos. Although Yukawa matrices are hierarchical in the models we consider, the mixing between second- and third-generation neutrinos is naturally large. We first present a quantitative analysis of a minimal model proposed in earlier work, consisting of a global fit to fermion masses and mixing angles, including the most important renormalization group effects. We then propose two new variant models: The first reproduces all important features of the SU(5)xU(2) unified theory with neither SU(5) nor U(2). The second demonstrates that discrete subgroups of SU(2) can be used in constructing viable supersymmetric theories of flavor without scalar universality even though SU(2) by itself cannot.Comment: 34 pages LaTeX, 1 eps figure, minor revisions and references adde

When “perverts” were religious: the Protestant sexualisation of asceticism in nineteenth-century Britain, India and Ireland

Anti-Catholic polemics from the mid-nineteenth century made frequent comparison between religious practices in Britain, Ireland and India. The supposed atrocities taking place at locations such as Lough Dearg in Country Donegal and at ‘Juggernaut’ (Jagganath) at Puri were denounced in terms which hinted strongly at a striking combination of extreme asceticism and perverse sexual enjoyment. In the same period the word ‘perversion’, which had hitherto referred to apostasy, started to develop connotations of sexual deviance. Protestant sexualised readings of Catholic and Hindu asceticism appear to have been an important site for the development of conceptions of deviant sexuality in general and masochism in particular