8,856 research outputs found
Non-Abelian Statistics of Axion Strings
We examine an axion string coupled to a Majorana fermion. It is found that
there exist a Majorana-Weyl zero mode on the string. Due to the zero mode, the
axion strings obey non-abelian statistics.Comment: 10 pages, 1 figure, references and comments adde
The Limits of Anthropocene Narratives
The rapidly growing transdisciplinary enthusiasm about developing new kinds of Anthropocene stories is based on the shared assumption that the Anthropocene predicament is best made sense of by narrative means. Against this assumption, this article argues that the challenge we are facing today does not merely lie in telling either scientific, socio-political, or entangled Anthropocene narratives to come to terms with our current condition. Instead, the challenge lies in coming to grips with how the stories we can tell in the Anthropocene relate to the radical novelty of the Anthropocene condition about which no stories can be told. What we need to find are meaningful ways to reconcile an inherited commitment to narrativization and the collapse of storytelling as a vehicle of understanding the Anthropocene as our current predicament
Investigation of oscillation frequency and disorder induced dynamic phase transitions in a quenched-bond diluted Ising ferromagnet
Frequency evolutions of hysteresis loop area and hysteresis tools such as
remanence and coercivity of a kinetic Ising model in the presence of quenched
bond dilution are investigated in detail. The kinetic equation describing the
time dependence of the magnetization is derived by means of effective-field
theory with single-site correlations. It is found that the frequency
dispersions of hysteresis loop area, remanence and coercivity strongly depend
on the quenched bond randomness, as well as applied field amplitude and
oscillation frequency. In addition, the shape of the hysteresis curves for a
wide variety of Hamiltonian parameters is studied and some interesting
behaviors are found. Finally, a comparison of our observations with those of
recently published studies is represented and it is shown that there exists a
qualitatively good agreement.Comment: 11 pages, 8 figure
Spin-orbit torque-driven magnetization switching and thermal effects studied in Ta\CoFeB\MgO nanowires
We demonstrate magnetization switching in out-of-plane magnetized Ta\CoFeB\MgO nanowires by current pulse injection along the nanowires, both with and without a constant and uniform magnetic field collinear to the current direction. We deduce that an effective torque arising from spin-orbit effects in the multilayer drives the switching mechanism. While the generation of a component of the magnetization along the current direction is crucial for the switching to occur, we observe that even without a longitudinal field thermally generated magnetization fluctuations can lead to switching. Analysis using a generalized Néel-Brown model enables key parameters of the thermally induced spin-orbit torques-driven switching process to be estimated, such as the attempt frequency and the effective energy barrier
How cold is Dark Matter? Constraints from Milky Way Satellites
We test the luminosity function of Milky Way satellites as a constraint for
the nature of Dark Matter particles. We perform dissipationless high-resolution
N-body simulations of the evolution of Galaxy-sized halo in the standard Cold
Dark Matter (CDM) model and in four Warm Dark Matter (WDM) scenarios, with a
different choice for the WDM particle mass (m_w). We then combine the results
of the numerical simulations with semi-analytic models for galaxy formation, to
infer the properties of the satellite population. Quite surprisingly we find
that even WDM models with relatively low m_w values (2-5 keV) are able to
reproduce the observed abundance of ultra faint (Mv<-9) dwarf galaxies, as well
as the observed relation between Luminosity and mass within 300 pc. Our results
suggest a lower limit of 1 keV for thermal warm dark matter, in broad agreement
with previous results from other astrophysical observations like Lyman-alpha
forest and gravitational lensing.Comment: 6 pages, 5 figures. Introduction improved, references added. Accepted
for publication on MNRAS Letter
Pseudo-Hermitian continuous-time quantum walks
In this paper we present a model exhibiting a new type of continuous-time
quantum walk (as a quantum mechanical transport process) on networks, which is
described by a non-Hermitian Hamiltonian possessing a real spectrum. We call it
pseudo-Hermitian continuous-time quantum walk. We introduce a method to obtain
the probability distribution of walk on any vertex and then study a specific
system. We observe that the probability distribution on certain vertices
increases compared to that of the Hermitian case. This formalism makes the
transport process faster and can be useful for search algorithms.Comment: 13 page, 7 figure
Neonatal-onset multisystem inflammatory disease responsive to interleukin-1 beta inhibition
BACKGROUND:Neonatal-onset multisystem inflammatory disease is characterized by fever, urticarial rash, aseptic meningitis, deforming arthropathy, hearing loss, and mental retardation. Many patients have mutations in the cold-induced autoinflammatory syndrome 1 (CIAS1) gene, encoding cryopyrin, a protein that regulates inflammation.METHODS:We selected 18 patients with neonatal-onset multisystem inflammatory disease (12 with identifiable CIAS1 mutations) to receive anakinra, an interleukin-1-receptor antagonist (1 to 2 mg per kilogram of body weight per day subcutaneously). In 11 patients, anakinra was withdrawn at three months until a flare occurred. The primary end points included changes in scores in a daily diary of symptoms, serum levels of amyloid A and C-reactive protein, and the erythrocyte sedimentation rate from baseline to month 3 and from month 3 until a disease flare.RESULTS:All 18 patients had a rapid response to anakinra, with disappearance of rash. Diary scores improved (P<0.001) and serum amyloid A (from a median of 174 mg to 8 mg per liter), C-reactive protein (from a median of 5.29 mg to 0.34 mg per deciliter), and the erythrocyte sedimentation rate decreased at month 3 (all P<0.001), and remained low at month 6. Magnetic resonance imaging showed improvement in cochlear and leptomeningeal lesions as compared with baseline. Withdrawal of anakinra uniformly resulted in relapse within days; retreatment led to rapid improvement. There were no drug-related serious adverse events.CONCLUSIONS:Daily injections of anakinra markedly improved clinical and laboratory manifestations in patients with neonatal-onset multisystem inflammatory disease, with or without CIAS1 mutations
Anyons and the quantum Hall effect - a pedagogical review
The dichotomy between fermions and bosons is at the root of many physical
phenomena, from metallic conduction of electricity to super-fluidity, and from
the periodic table to coherent propagation of light. The dichotomy originates
from the symmetry of the quantum mechanical wave function to the interchange of
two identical particles. In systems that are confined to two spatial dimensions
particles that are neither fermions nor bosons, coined "anyons", may exist. The
fractional quantum Hall effect offers an experimental system where this
possibility is realized. In this paper we present the concept of anyons, we
explain why the observation of the fractional quantum Hall effect almost forces
the notion of anyons upon us, and we review several possible ways for a direct
observation of the physics of anyons. Furthermore, we devote a large part of
the paper to non-abelian anyons, motivating their existence from the point of
view of trial wave functions, giving a simple exposition of their relation to
conformal field theories, and reviewing several proposals for their direct
observation.Comment: Invited review for the Annals of Physic
Nonabelian Vortices on Surfaces and Their Statistics
We discuss the physics of topological vortices moving on an arbitrary surface
M in a Yang-Mills-Higgs theory in which the gauge group G breaks to a finite
subgroup H. We concentrate on the case where M is compact and/or nonorientable.
Interesting new features arise which have no analog on the plane. The
consequences for the quantum statistics of vortices are discussed, particularly
when H is nonabelian.Comment: 27 pages, 6 figures, requires harvma
An integrated general practice and pharmacy-based intervention to promote the use of appropriate preventive medications among individuals at high cardiovascular disease risk: protocol for a cluster randomized controlled trial
Background: Cardiovascular diseases (CVD) are responsible for significant morbidity, premature mortality, and economic burden. Despite established evidence that supports the use of preventive medications among patients at high CVD risk, treatment gaps remain. Building on prior evidence and a theoretical framework, a complex intervention has been designed to address these gaps among high-risk, under-treated patients in the Australian primary care setting. This intervention comprises a general practice quality improvement tool incorporating clinical decision support and audit/feedback capabilities; availability of a range of CVD polypills (fixed-dose combinations of two blood pressure lowering agents, a statin ± aspirin) for prescription when appropriate; and access to a pharmacy-based program to support long-term medication adherence and lifestyle modification.
Methods: Following a systematic development process, the intervention will be evaluated in a pragmatic cluster randomized controlled trial including 70 general practices for a median period of 18 months. The 35 general practices in the intervention group will work with a nominated partner pharmacy, whereas those in the control group will provide usual care without access to the intervention tools. The primary outcome is the proportion of patients at high CVD risk who were inadequately treated at baseline who achieve target blood pressure (BP) and low-density lipoprotein cholesterol (LDL-C) levels at the study end. The outcomes will be analyzed using data from electronic medical records, utilizing a validated extraction tool. Detailed process and economic evaluations will also be performed.
Discussion: The study intends to establish evidence about an intervention that combines technological innovation with team collaboration between patients, pharmacists, and general practitioners (GPs) for CVD prevention.
Trial registration: Australian New Zealand Clinical Trials Registry ACTRN1261600023342
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