Cross-Sectional Associations of 24-Hour Sedentary Time, Physical Activity, and Sleep Duration Compositions with Sleep Quality and Habits in Preschoolers

Although some studies indicate physical activity and sleep quality are positively associated in children, most reports examined physical activity independent of other 24-h behaviors and focused on older children. The aim of this cross-sectional study was to examine the predicted changes in sleep efficiency and habits when reallocating time between movement behaviors using compositional isotemporal substitution in preschool-aged children. Accelerometers were worn by 288 participants (51.6 ± 9.5 months) for up to 16 days. Sleep outcomes included sleep efficiency, nap frequency, sleep disturbances, and bedtime resistance. Compositional isotemporal substitution analyses demonstrated that the combined effect of 24-h movement behaviors was associated with sleep efficiency (p \u3c 0.001) and nap frequency (p \u3c 0.003). When sleep increased by 30 min at the expense of stationary time or light physical activity, estimates of sleep efficiency and bedtime resistance decreased while nap frequency increased. When stationary time increased by 30 min from moderate to vigorous physical activity, estimated sleep efficiency increased and sleep disturbances decreased. Although this study presents preliminary evidence that 24-h movement behavior compositions in early childhood are associated with sleep quality and nap frequency, estimated effects from theoretical time reallocations across sleep outcomes were mixed

Characterization of relativistic electron bunch duration and travelling wave structure phase velocity based on momentum spectra measurements on the ARES linac at DESY

The ARES linac at DESY aims to generate and characterize ultrashort electron bunches (fs to sub-fs duration) with high momentum and arrival time stability for the purpose of applications related to accelerator R&D, e.g. development of advanced and compact diagnostics and accelerating structures, test of new accelerator components, medical applications studies, machine learning, etc. During its commissioning phase, the bunch duration characterization of the electron bunches generated at ARES has been performed with an RF-phasing technique relying on momentum spectra measurements, using only common accelerator elements (RF accelerating structures and magnetic spectrometers). The sensitivity of the method allowed highlighting different response times for Mo and Cs2Te cathodes. The measured electron bunch duration in a wide range of machine parameters shows excellent agreement overall with the simulation predictions, thus demonstrating a very good understanding of the ARES operation on the bunch duration aspect. The importance of a precise in-situ experimental determination of the phase velocity of the first travelling wave accelerating structure after the electron source, for which we propose a simple new beam-based method precise down to sub-permille variation respective to the speed of light in vacuum, is emphasized for this purpose. A minimum bunch duration of 20 fs rms, resolution-limited by the space charge forces, is reported. This is, to the best of our knowledge, around 4 times shorter than what has been previously experimentally demonstrated based on RF-phasing techniques with a single RF structure. The present study constitutes a strong basis for future time characterization down to the sub-fs level at ARES, using dedicated X-band transverse deflecting structures.Comment: 17 pages, 11 figures. To be submitted to Physical Review Accelerators and Beam

Nonadjacent dependency processing in monkeys, apes and humans

The ability to track syntactic relationships between words, particularly over distances (“nonadjacent dependencies”), is a critical faculty underpinning human language, although its evolutionary origins remain poorly understood. While some monkey species are reported to process auditory nonadjacent dependencies, comparative data from apes are missing, complicating inferences regarding shared ancestry. Here, we examined nonadjacent dependency processing in common marmosets, chimpanzees, and humans using “artificial grammars”: strings of arbitrary acoustic stimuli composed of adjacent (nonhumans) or nonadjacent (all species) dependencies. Individuals from each species (i) generalized the grammars to novel stimuli and (ii) detected grammatical violations, indicating that they processed the dependencies between constituent elements. Furthermore, there was no difference between marmosets and chimpanzees in their sensitivity to nonadjacent dependencies. These notable similarities between monkeys, apes, and humans indicate that nonadjacent dependency processing, a crucial cognitive facilitator of language, is an ancestral trait that evolved at least ~40 million years before language itself

Towards a Notion of Distributed Time for Petri Nets

We set the ground for research on a timed extension of Petri nets where time parameters are associated with tokens and arcs carry constraints that qualify the age of tokens required for enabling. The novelty is that, rather than a single global clock, we use a set of unrelated clocks --- possibly one per place --- allowing a local timing as well as distributed time synchronisation. We give a formal definition of the model and investigate properties of local versus global timing, including decidability issues and notions of processes of the respective models

End-of-fill study on collimator tight settings

In 2010 and 2011 the collimation system has been operated with relaxed settings, i.e. with retractions between different collimator families larger than the nominal settings that provide optimum cleaning. This configuration ensured a sufficient cleaning performance at 3.5 TeV while allowing larger tolerances on orbit control. Tighter collimator settings were proposed to push the cleaning performance and to allow larger orbit margins between TCDQ dump protection and tertiary collimators. With the same margins as with the relaxed settings, the β∗ could be reduced. After having verified with beam that the cleaning is improved as expected, the feasibility of tighter collimator settings must be addressed with high stored intensity. For this purpose, an end-of-fill study was proposed after a standard physics fill with 1380 bunches nominal bunches at 3.5 TeV, for a total stored energy of 95 MJ. During this test, primary and secondary collimators were moved to tight settings after about 8 hours of stable physics conditions in all experiments. This note summarises the operational procedure followed and the results of beam measurements during this study.peer-reviewe

The Longitudinal Polarimeter at HERA

The design, construction and operation of a Compton back-scattering laser polarimeter at the HERA storage ring at DESY are described. The device measures the longitudinal polarization of the electron beam between the spin rotators at the HERMES experiment with a fractional systematic uncertainty of 1.6%. A measurement of the beam polarization to an absolute statistical precision of 0.01 requires typically one minute when the device is operated in the multi-photon mode. The polarimeter also measures the polarization of each individual electron bunch to an absolute statistical precision of 0.06 in approximately five minutes. It was found that colliding and non-colliding bunches can have substantially different polarizations. This information is important to the collider experiments H1 and ZEUS for their future longitudinally polarized electron program because those experiments use the colliding bunches only.Comment: 21 pages (Latex), 14 figures (EPS

What Do Program Directors Value in Personal Statements? A Qualitative Analysis

Background: All applicants to accredited training programs must write a personal statement as part of the application process. This may provoke anxiety on the part of the applicant and can result in an impersonal product that does not enhance his or her application. Little has been written about what program directors are seeking in personal statements. Objective: To gain a better understanding of how pulmonary and critical care fellowship program directors view and interpret these essays and to help applicants create more effective personal statements and make the writing process less stressful. Methods: We surveyed the membership of the Association of Pulmonary and Critical Care Medicine Program Directors in 2018. Quantitative data were collected regarding the importance of the personal statement in the candidate selection process. Qualitative data exploring the characteristics of personal statements, what the personal statement reveals about applicants, and advice for writing them were also collected. Comparative analysis was used for coding and analysis of qualitative data. Results: Surveys were completed by 114 out of 344 possible respondents (33%). More than half of the respondents believed that the personal statement is at least moderately important when deciding to offer an interview, and 40% believed it is at least moderately important when deciding rank order. A qualitative analysis revealed consistent themes: communication skills, provision of information not found elsewhere, applicant characteristics, and things to avoid. Conclusion: The respondents view the personal statement as moderately important in the application process. They value succinct, quality writing that reveals personal details not noted elsewhere. The information presented may help reduce anxiety associated with writing the personal statement and result in making the personal statement a more meaningful part of the application

A First Look at Rotation in Inactive Late-Type M Dwarfs

We have examined the relationship between rotation and activity in 14 late-type (M6-M7) M dwarfs, using high resolution spectra taken at the W.M. Keck Observatory and flux-calibrated spectra from the Sloan Digital Sky Survey. Most were selected to be inactive at a spectral type where strong H-alpha emission is quite common. We used the cross-correlation technique to quantify the rotational broadening; six of the stars in our sample have vsini > 3.5 km/s. Our most significant and perplexing result is that three of these stars do not exhibit H-alpha emission, despite rotating at velocities where previous work has observed strong levels of magnetic field and stellar activity. Our results suggest that rotation and activity in late-type M dwarfs may not always be linked, and open several additional possibilities including a rotationally-dependent activity threshold, or a possible dependence on stellar parameters of the Rossby number at which magnetic/activity "saturation" takes place in fully convective stars.Comment: 8 pages, 4 figures, accepted for publication in Ap

Detours and Paths: BRST Complexes and Worldline Formalism

We construct detour complexes from the BRST quantization of worldline diffeomorphism invariant systems. This yields a method to efficiently extract physical quantum field theories from particle models with first class constraint algebras. As an example, we show how to obtain the Maxwell detour complex by gauging N=2 supersymmetric quantum mechanics in curved space. Then we concentrate on first class algebras belonging to a class of recently introduced orthosymplectic quantum mechanical models and give generating functions for detour complexes describing higher spins of arbitrary symmetry types. The first quantized approach facilitates quantum calculations and we employ it to compute the number of physical degrees of freedom associated to the second quantized, field theoretical actions.Comment: 1+35 pages, 1 figure; typos corrected and references added, published versio

Changes in vegetation composition and structure following livestock exclusion in a temperate fluvial wetland

Questions: Responses of wetland systems to grazing can be highly variable with both positive or negative responses. However, the sustainable use of wetlands for grazing will depend on the management implemented and the resilience of each type of them. In this context, we addressed the question: will the vegetation in the studied wetland be able to recover its structural and functional parameters in the short term after livestock exclusion?. Location: Temperate fluvial wetlands in the middle Delta of the Paraná River, Argentina, South America. Methods: We evaluated the effect of cattle ranching on vegetation composition and diversity by determining changes in species richness and evenness, biomass (green and dry vegetative, and reproductive biomass), and litter content. We also analyzed the changes in biomass of weeds and of species according to their forage quality, toxicity, and growth form. We applied a randomized block design (by topographic position) with repeated measures over time, using livestock exclusion as treatment. Results: After 16 months, livestock exclusion affected vegetation species richness, but did not have a significant effect on diversity due to a slightly compensatory effect of evenness. Species composition differed markedly among treatments over time. There was an increase in dry and green vegetative biomass and litter content after eight months of exclusion, while changes in reproductive biomass occurred later. The increase in these variables was closely related to changes in biomass of species with erect habit and good forage quality. Conclusions: Livestock exclusion increased the forage value for the studied wetland by the development of natural palatable species typical of these environments. This shift in species composition promoted a higher production in biomass in the ungrazed areas. This suggests a remarkable recovery of the structural and functional parameters of the vegetation communities in the short term (two years).Fil: Magnano, Andrea Laura. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto Argentino de Investigaciones de las Zonas Áridas. Provincia de Mendoza. Instituto Argentino de Investigaciones de las Zonas Áridas. Universidad Nacional de Cuyo. Instituto Argentino de Investigaciones de las Zonas Áridas; ArgentinaFil: Krug, Cecilia Pamela. Universidad Nacional de San Martín. Instituto de Investigación e Ingeniería Ambiental. - Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigación e Ingeniería Ambiental; ArgentinaFil: Casa, Valeria. Universidad Nacional de San Martín. Instituto de Investigación e Ingeniería Ambiental. - Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigación e Ingeniería Ambiental; ArgentinaFil: Quintana, Ruben Dario. Universidad Nacional de San Martín. Instituto de Investigación e Ingeniería Ambiental. - Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigación e Ingeniería Ambiental; Argentin