Multi-D magnetohydrodynamic modelling of pulsar wind nebulae: recent progress and open questions

In the last decade, the relativistic magnetohydrodynamic (MHD) modelling of pulsar wind nebulae, and of the Crab nebula in particular, has been highly successful, with many of the observed dynamical and emission properties reproduced down to the finest detail. Here, we critically discuss the results of some of the most recent studies: namely the investigation of the origin of the radio emitting particles and the quest for the acceleration sites of particles of different energies along the termination shock, by using wisps motion as a diagnostic tool; the study of the magnetic dissipation process in high magnetization nebulae by means of new long-term three-dimensional simulations of the pulsar wind nebula evolution; the investigation of the relativistic tearing instability in thinning current sheets, leading to fast reconnection events that might be at the origin of the Crab nebula gamma-ray flares.Comment: 30 pages, 12 figure

Relativistic MHD modeling of magnetized neutron stars, pulsar winds, and their nebulae

Neutron stars are among the most fascinating astrophysical sources, being characterized by strong gravity, densities about the nuclear one or even above, and huge magnetic fields. Their observational signatures can be extremely diverse across the electromagnetic spectrum, ranging from the periodic and low-frequency signals of radio pulsars, up to the abrupt high-energy gamma-ray flares of magnetars, where energies of ~10^46 erg are released in a few seconds. Fast-rotating and highly magnetized neutron stars are expected to launch powerful relativistic winds, whose interaction with the supernova remnants gives rise to the non-thermal emission of pulsar wind nebulae, which are known cosmic accelerators of electrons and positrons up to PeV energies. In the extreme cases of proto-magnetars (magnetic fields of ~10^15 G and millisecond periods), a similar mechanism is likely to provide a viable engine for the still mysterious gamma-ray bursts. The key ingredient in all these spectacular manifestations of neutron stars is the presence of strong magnetic fields in their constituent plasma. Here we will present recent updates of a couple of state-of-the-art numerical investigations by the high-energy astrophysics group in Arcetri: a comprehensive modeling of the steady-state axisymmetric structure of rotating magnetized neutron stars in general relativity, and dynamical 3-D MHD simulations of relativistic pulsar winds and their associated nebulae.Comment: EPS 44th Conference on Plasma Physics (June 2017, Belfast), paper accepted for publication on Plasma Physics and Controlled Fusio

Effects of Misinformation as Revealed Through the Concealed Knowledge Test

Misinformation effects occur reliably in laboratory settings despite disagreement over the mechanism(s) responsible for such effects. Both memory impairment hypotheses (e.g.f Lindsay & Johnson, 1987; Loftus 1975, 1977, 1979; Loftus & Hoffman, 1989; Tversky & Tuchin, 1989) and non-impairment hypotheses (e.g., McCloskey & Zaragoza, 1985; Zaragoza, McCloskey, & Jamis, 1987) have been used to explain the phenomenon of misinformation. The present study examined the effects of misinformation on the Concealed Knowledge Test (CKT), a psychophysiological detection of deception technique. Furthermore, the psychophysiological measurements were used to elucidate the controversy surrounding the misinformation effect. Ninety-six subjects watched a videotaped crime used to induce guilt. One week later, subjects were given misinformation about three details of the crime, took a CKT inquiring about the three misled details and three non-misled details of the crime, and took a 20-item recognition memory test concerning the crime. The six details questioned during the CKT were also included in the memory test. Subjects who chose the misinformation on a misled detail were labeled as successfully misinformed regarding that detail. Significant differences in the Lykken (1959) method of scoring the CKT were found between the misled and non-misled CKT series, with misinformation leading to a lower score (i.e., higher probability of being categorized as truthful). A MANOVA demonstrated a significant interaction [Wilks F(18, 3946) = 5.36, p = .000] between type of detail on the CKT (key, misinformation, foil) and information manipulation (non-misled, unsuccessfully misled, and successfully misled) with univariate procedures identifying skin resistance amplitude, skin resistance half-recovery time, and abdominal respiration as significant dependent measures. Follow-up analyses demonstrated that on successfully misled CKT charts, subjects7 responses to the misinformation were significantly stronger than were responses to both the original detail and neutral foils (which did not differ). These findings, supportive of memory impairment hypotheses, are discussed in terms of the (un)permanence of memory

Functional, Sub-100 nm Polymer Nanoparticles \u3ci\u3evia\u3c/i\u3e Thiol-ene Miniemulsion Photopolymerization

In this work, sub-100 nm crosslinked polythioether nanoparticles were synthesized via thiol–ene photopolymerization in miniemulsion using high-energy homogenization. The effects of the miniemulsion formulation and homogenization parameters – including inhibitor concentration, surfactant concentration, organic weight fraction, ultrasonication time and amplitude – on nanoparticle size and size distribution were investigated. Thiol–ene nanoparticles with a mean particle diameter of 46 nm were obtained under optimized conditions for the current system at 2.5 wt% organic fraction and 20 mM surfactant concentration. In an effort to demonstrate potential utility of thiol–ene nanoparticles, we exploit the step-growth radical mechanism of thiol–ene photopolymerization under non-stoichiometric conditions to fabricate functional nanoparticles that express excess thiol or alkene at the particle surface. We show that these excess functional groups can be utilized as reactive handles in thiol-Michael and radical-mediated thiol–ene reactions for immobilization of fluorescent moieties via postpolymerization modification

Methodological and terminological issues in animal-assisted interventions: An umbrella review of systematic reviews

Recently, animal-assisted interventions (AAIs), which are defined as psychological, educational, and rehabilitation support activities, have become widespread in different contexts. For many years, they have been a subject of interest in the international scientific community and are at the center of an important discussion regarding their effectiveness and the most appropriate practices for their realization. We carried out an umbrella review (UR) of systematic reviews (SRs), created for the purpose of exploring the literature and aimed at deepening the terminological and methodological aspects of AAIs. It is created by exploring the online databases PubMed, Google Scholar, and Cochrane Library. The SRs present in the high-impact indexed search engines Web of Sciences and Scopus are selected. After screening, we selected 15 SRs that met the inclusion criteria. All papers complained of the poor quality of AAIs; some considered articles containing interventions that did not always correspond to the terminology they have explored and whose operating practices were not always comparable. This stresses the need for the development and consequent diffusion of not only operational protocols, but also research protocols which provide for the homogeneous use of universally recognized terminologies, thus facilitating the study, deepening, and comparison between the numerous experiences described

Application of EREP imagery to fracture-related mine safety hazards in coal mining and mining-environmental problems in Indiana

The author has identified the following significant results. This investigation evaluated the applicability of a variety of sensor types, formats, and resolution capabilities to the study of both fuel and nonfuel mined lands. The image reinforcement provided by stereo viewing of the EREP images proved useful for identifying lineaments and for mined lands mapping. Skylab S190B color and color infrared transparencies were the most useful EREP imagery. New information on lineament and fracture patterns in the bedrock of Indiana and Illinois extracted from analysis of the Skylab imagery has contributed to furthering the geological understanding of this portion of the Illinois basin

Horizontal Gaze Nystagmus Test: The State of the Science in 1995

The horizontal gaze nystagmus test (HGNT) is one component of field sobriety testing conducted by police officers to determine whether a suspect is intoxicated. The HGNT is the centerpiece of the National Highway Traffic and Safety Administration\u27s (NHTSA) Standardized Field Sobriety Tests. The walk-and-turn test and the one-leg-stand test are also included in this three-test battery of field sobriety tests. Prior to the NHTSA funded work at standardizing field sobriety testing, roadside tests were selected and administered according to personal preferences. Today, however, many police agencies and officers use the standardized three-test battery that resulted from NHTSA\u27s work. Although the HGNT is used in conjunction with the walk-and-turn and the one-leg-stand tests, this discussion will focus solely on the HGNT due to the recent decision by the North Dakota Supreme Court in City of Fargo v. McLaughlin