Mode competition in a system of two parametrically driven pendulums with nonlinear coupling

This paper is part three in a series on the dynamics of two coupled, parametrically driven pendulums. In the previous parts Banning and van der Weele (1995) and Banning et al. (1997) studied the case of linear coupling; the present paper deals with the changes brought on by the inclusion of a nonlinear (third-order) term in the coupling. Special attention will be given to the phenomenon of mode competition.\ud \ud The nonlinear coupling is seen to introduce a new kind of threshold into the system, namely a lower limit to the frequency at which certain motions can exist. Another consequence is that the mode interaction between 1¿ and 2ß (two of the normal motions of the system) is less degenerate, causing the intermediary mixed motion known as MP to manifest itself more strongly

Measuring working memory load effects on electrophysiological markers of attention orienting during a simulated drive

Intersection accidents result in a significant proportion of road fatalities, and attention allocation likely plays a role. Attention allocation may depend on (limited) working memory (WM) capacity. Driving is often combined with tasks increasing WM load, consequently impairing attention orienting. This study (n = 22) investigated WM load effects on event-related potentials (ERPs) related to attention orienting. A simulated driving environment allowed continuous lane-keeping measurement. Participants were asked to orient attention covertly towards the side indicated by an arrow, and to respond only to moving cars appearing on the attended side by pressing a button. WM load was manipulated using a concurrent memory task. ERPs showed typical attentional modulation (cue: contralateral negativity, LDAP; car: N1, P1, SN and P3) under low and high load conditions. With increased WM load, lane-keeping performance improved, while dual task performance degraded (memory task: increased error rate; orienting task: increased false alarms, smaller P3). Practitioner Summary: Intersection driver-support systems aim to improve traffic safety and flow. However, in-vehicle systems induce WM load, increasing the tendency to yield. Traffic flow reduces if drivers stop at inappropriate times, reducing the effectiveness of systems. Consequently, driver-support systems could include WM load measurement during driving in the development phase

CRC general comments on children's health, impact of the business sector and the right to rest, leisure and play.

In April 2013, the UN Committee on the Rights of the Child (CRC) published the three General Comments which had been adopted at its 62nd session. General comments 15, 16 and 17 relate to the right of the child to enjoyment of the highest attainable standard of health; on State obligations regarding the impact of the business sector on children’s’ rights; and the right of the child to rest, leisure, play, recreational activities, cultural life and the arts, respectively

Electronic transport and vibrational modes in the smallest molecular bridge: H2 in Pt nanocontacts

We present a state-of-the-art first-principles analysis of electronic transport in a Pt nanocontact in the presence of H2 which has been recently reported by Smit et al. in Nature 419, 906 (2002). Our results indicate that at the last stages of the breaking of the Pt nanocontact two basic forms of bridge involving H can appear. Our claim is, in contrast to Smit et al.'s, that the main conductance histogram peak at G approx 2e^2/h is not due to molecular H2, but to a complex Pt2H2 where the H2 molecule dissociates. A first-principles vibrational analysis that compares favorably with the experimental one also supports our claim .Comment: 5 pages, 3 figure

Driving the Future: The Relation between Driving and Prospective Memory in Adults with an Autism Spectrum Disorder

Difficulties with autonomy impact several quality-of-life outcomes in people with autism spectrum disorder (ASD). Driving is an important step towards gaining autonomy by allowing the development and maintenance of work- and social-related contacts. Nonetheless, people with ASD depend highly on friends and family for their transportation needs. Due to the complexity of the driving task, specific ASD characteristics might interfere negatively with driving. The driving task consists of several subtasks, running in parallel. This requires the ability to switch in a smooth manner (e.g., shifting, steering, changing lanes, and keeping traffic rules into account). An additional difficulty concerns sudden changes in the traffic environment (e.g., traffic density, weather conditions). Therefore, driving is a complex goal-directed task that places high demands on perceptual, cognitive, and motor processes. The little research that exists suggests that people with ASD experience difficulties more specifically in complex driving situations, requiring multi-tasking and inducing increased cognitive load. Applied to autonomy, in order to maintain work and social contacts, it is not only necessary to handle the vehicle, but also to navigate through rural, urban, and highway traffic environments while concurrently remembering appointments and obeying a schedule. People with ASD however experience difficulties with coordinating and sequencing activities, and with planning ahead. Following this, prospective memory (PM) might interfere negatively with driving. PM is the ability to remember to carry out intended actions in the future while being engaged in other ongoing activities. Two subtypes of PM are event-based PM (EBPM) and time-based PM (TBPM). The former refers to the execution of intentions at certain events (i.e., prospective cues), the latter refers to the execution of intentions at certain times. This driving simulator study aims to investigate PM (i.e., EBPM and TBPM) as an underlying mechanism of driving in adults with ASD. To this end, a pc-based ‘virtual reality (VR) city task’ was translated to a driving simulator environment. The influence of several cognitive abilities (e.g., working memory, planning), from which the importance is indicated in previous literature, is also investigated. Data collection is ongoing and will be finished in December. The analyses are planned in January

Fluoroquinolone antibiotics and tendon injury in adolescents

OBJECTIVES: To estimate the association between fluoroquinolone use and tendon injury in adolescents. METHODS: We conducted an active-comparator, new-user cohort study using population-based claims data from 2000 to 2018. We included adolescents (aged 12-18 years) with an outpatient prescription fill for an oral fluoroquinolone or comparator broad-spectrum antibiotic. The primary outcome was Achilles, quadricep, patellar, or tibial tendon rupture identified by diagnosis and procedure codes. Tendinitis was a secondary outcome. We used weighting to adjust for measured confounding and a negative control outcome to assess residual confounding. RESULTS: The cohort included 4.4 million adolescents with 7.6 million fills for fluoroquinolone (275 767 fills) or comparator (7 365 684) antibiotics. In the 90 days after the index antibiotic prescription, there were 842 tendon ruptures and 16 750 tendinitis diagnoses (crude rates 0.47 and 9.34 per 1000 person-years, respectively). The weighted 90-day tendon rupture risks were 13.6 per 100 000 fluoroquinolone-treated adolescents and 11.6 per 100 000 comparator-treated adolescents (fluoroquinolone-associated excess risk: 1.9 per 100 000 adolescents; 95% confidence interval 22.6 to 6.4); the corresponding number needed to treat to harm was 52 632. For tendinitis, the weighted 90-day risks were 200.8 per 100 000 fluoroquinolone-treated adolescents and 178.1 per 100 000 comparator-treated adolescents (excess risk: 22.7 per 100 000; 95% confidence interval 4.1 to 41.3); the number needed to treat to harm was 4405. CONCLUSIONS: The excess risk of tendon rupture associated with fluoroquinolone treatment was extremely small, and these events were rare. The excess risk of tendinitis associated with fluoroquinolone treatment was also small. Other more common potential adverse drug effects may be more important to consider for treatment decision-making, particularly in adolescents without other risk factors for tendon injury

On the massless "just-so" solution to the solar neutrino problem

We study the effect of the non-resonant, vacuum oscillation-like neutrino flavor conversion induced by non-standard flavor changing and non-universal flavor diagonal neutrino interactions with electrons in the sun. We have found an acceptable fit for the combined analysis for the solar experiments total rates, the Super-Kamiokande (SK) energy spectrum and zenith angle dependence. Phenomenological constraints on non-standard flavor changing and non-universal flavor diagonal neutrino interactions are considered.Comment: 4 pages, Latex, uses eps

Effects of new physics in neutrino oscillations in matter

A new flavor changing electron neutrino interaction with matter would always dominate the nu_e oscillation probability at sufficiently high neutrino energies. Being suppressed by theta_{13}, the energy scale at which the new effect starts to be relevant may be within the reach of realistic experiments, where the peculiar dependence of the signal with energy could give rise to a clear signature in the nu_e --> nu_tau channel. The latter could be observed by means of a coarse large magnetized detector by exploiting tau --> mu decays. We discuss the possibility of identifying or constraining such effects with a high energy neutrino factory. We also comment on the model independent limits on them.Comment: 11 pages, 5 figure

A fossil winonaite-like meteorite in Ordovician limestone: A piece of the impactor that broke up the L-chondrite parent body?

AbstractAbout a quarter of all meteorites falling on Earth today originate from the breakup of the L-chondrite parent body ∼470 Ma ago, the largest documented breakup in the asteroid belt in the past ∼3 Ga. A window into the flux of meteorites to Earth shortly after this event comes from the recovery of about 100 fossil L chondrites (1–21 cm in diameter) in a quarry of mid-Ordovician limestone in southern Sweden. Here we report on the first non-L-chondritic meteorite from the quarry, an 8 cm large winonaite-related meteorite of a type not known among present-day meteorite falls and finds. The noble gas data for relict spinels recovered from the meteorite show that it may be a remnant of the body that hit and broke up the L-chondrite parent body, creating one of the major asteroid families in the asteroid belt. After two decades of systematic recovery of fossil meteorites and relict extraterrestrial spinel grains from marine limestone, it appears that the meteorite flux to Earth in the mid-Ordovician was very different from that of today