bluuebunny/crossref_metadata_2025 huggingface dataset:
Diurnal vertical and seasonal changes in non-structural carbohydrates in Marandu palisade grass
Authors: De Oliveira F. C. Leite , Sanchez J. M. D. , Vendramini J. M. B. , Lima C. G. , Luz P. H. C. , Rocha C. O. , Pereira L. E. T. , Herling V. R.
Published: May 2018

Forage is the primary feed source for livestock in tropical regions and energy is one of the most important nutrients for ruminant nutrition. The effects of harvest management of Marandu palisade grass (Brachiaria brizantha cv. Marandu Syn. Urochloa brizantha cv. Marandu) on non-structural carbohydrate (NSC) concentrations were evaluated. A plot (Experiment 1) and a greenhouse study (Experiment 2) were conducted in 2013–14. In Experiment 1, treatments were the factorial arrangement of two harvest times and two vertical canopy layers (upper and intermediate), distributed in a completely randomized design with five replicates. In Experiment 2, treatments were the factorial arrangement of six harvest times and two morphological fractions (leaf blade and pseudostem). In both experiments, NSC concentration increased during the day. Upper and intermediate canopy layers had greater NSC concentration at 15.00 than 06.00 h during spring and summer. In addition, the magnitude of NSC increase was greater in the upper than intermediate canopy layer and in spring than summer. Marandu palisade grass shows greater digestibility in the afternoon than morning, representing an opportunity to optimize energy concentration through harvest management.
The Role of Data Providers as Information Intermediaries
Authors: Schaub Nic
Published: June 2018

This study investigates whether financial data providers serve as information intermediaries in capital markets. To this end, I examine whether the timeliness of earnings information disseminated by First Call (Thomson Reuters) affects the market’s reaction to earnings announcements. I document that the immediate price and volume response is weaker and the post-earnings-announcement drift stronger for earnings news disseminated with a delay by First Call. To mitigate endogeneity concerns, I study the market reaction on the day of the delayed dissemination and show that a significant part of the stronger drift is clustered around this day.
LINK OF MOMENTS BEFORE AND AFTER TRANSFORMATIONS, WITH AN APPLICATION TO RESAMPLING FROM FAT-TAILED DISTRIBUTIONS
Authors: Abadir Karim M. , Cornea-Madeira Adriana
Published: June 2018

Let x be a transformation of y, whose distribution is unknown. We derive an expansion formulating the expectations of x in terms of the expectations of y. Apart from the intrinsic interest in such a fundamental relation, our results can be applied to calculating E(x) by the low-order moments of a transformation which can be chosen to give a good approximation for E(x). To do so, we generalize the approach of bounding the terms in expansions of characteristic functions, and use our result to derive an explicit and accurate bound for the remainder when a finite number of terms is taken. We illustrate one of the implications of our method by providing accurate naive bootstrap confidence intervals for the mean of any fat-tailed distribution with an infinite variance, in which case currently available bootstrap methods are asymptotically invalid or unreliable in finite samples.
Caused motion across child languages: a comparison of English, German, and French
Authors: HICKMANN Maya , HENDRIKS Henriëtte , HARR Anne-Katharina , BONNET Philippe
Published: June 2018

Previous research on motion expression indicates that typological properties influence how speakers select and express information in discourse (Slobin, 2004; Talmy, 2000). The present study further addresses this question by examining the expression of caused motion by adults and children (three to ten years) in French (Verb-framed) vs. English and German (Satellite-framed). Participants narrated short animated cartoons showing an agent displacing objects and varying along several dimensions (Path, Manner). A significant increase with age was found in the number of expressed motion components in all languages, as well as an influence of Path (vertical > boundary crossing). However, at all ages, participants encoded more information in English and German than in French, where more variation and structural changes occurred with increasing age. These findings highlight both cognitive and typological factors impacting the expression of caused motion in development. Implications of our findings are sketched in the ‘Discussion’.
Sums of class numbers and mixed mock modular forms
Authors: BRINGMANN KATHRIN , KANE BEN
Published: June 2018

In this paper, we consider sums of class numbers of the type ∑m≡a(modp)H(4n−m2), wherepis an odd prime,n∈ ℕ, anda∈ ℤ. By showing that these are coefficients of mixed mock modular forms, we obtain explicit formulas. Using these formulas forp= 5 and 7, we then prove a conjecture of Brown et al. in the case thatn= ℓ is prime.
Energy intake and food sources of eight Latin American countries: results from the Latin American Study of Nutrition and Health (ELANS)
Authors: Kovalskys Irina , Fisberg Mauro , Gómez Georgina , Pareja Rossina G , Yépez García Martha C , Cortés Sanabria Lilia Y , Herrera-Cuenca Marianella , Rigotti Attilio , Guajardo Viviana , Zalcman Zimberg Ioná , Nogueira Previdelli Agatha , Moreno Luis A , Koletzko Berthold ,   the ELANS Study Group
Published: May 2018

Objective

Few previous studies in Latin America (LA) have provided data on dietary intake composition with a standardized methodology. The present study aimed to characterize energy intake (EI) and to describe the main food sources of energy in representative samples of the urban population from eight LA countries from the Latin American Study in Nutrition and Health (ELANS).

Design

Cross-sectional study. Usual dietary intake was assessed with two non-consecutive 24 h dietary recalls.

Setting

Urban areas from eight countries (Argentina, Brazil, Chile, Colombia, Costa Rica, Ecuador, Peru, Venezuela), September 2014 to July 2015.

Subjects

Adolescents and adults aged 15–65 years. Final sample comprised 9218 individuals, of whom 6648 (72·1 %) were considered plausible reporters.

Results

Overall, mean EI was 8196 kJ/d (1959 kcal/d), with a balanced distribution of macronutrients (54 % carbohydrate, 30 % fat, 16 % protein). Main food sources of energy were grains, pasta and bread (28 %), followed by meat and eggs (19 %), oils and fats (10 %), non-alcoholic homemade beverages (6 %) and ready-to-drink beverages (6 %). More than 25 % of EI was provided from food sources rich in sugar and fat, like sugary drinks, pastries, chips and candies. Meanwhile, only 18 % of EI was from food sources rich in fibre and micronutrients, such as whole grains, roots, fruits, vegetables, beans, fish and nuts. No critical differences were observed by gender or age.

Conclusions

Public health efforts oriented to diminish consumption of refined carbohydrates, meats, oils and sugar and to increase nutrient dense-foods are a priority in the region to drive to a healthier diet.
Electron Microscopy Imaging of Zinc Soaps Nucleation in Oil Paint
Authors: Hermans Joen , Osmond Gillian , van Loon Annelies , Iedema Piet , Chapman Robyn , Drennan John , Jack Kevin , Rasch Ronald , Morgan Garry , Zhang Zhi , Monteiro Michael , Keune Katrien
Published: June 2018

Using the recently developed techniques of electron tomography, we have explored the first stages of disfiguring formation of zinc soaps in modern oil paintings. The formation of complexes of zinc ions with fatty acids in paint layers is a major threat to the stability and appearance of many late 19th and early 20th century oil paintings. Moreover, the occurrence of zinc soaps in oil paintings leading to defects is disturbingly common, but the chemical reactions and migration mechanisms leading to large zinc soap aggregates or zones remain poorly understood. State-of-the-art scanning (SEM) and transmission (TEM) electron microscopy techniques, primarily developed for biological specimens, have enabled us to visualize the earliest stages of crystalline zinc soap growth in a reconstructed zinc white (ZnO) oil paint sample.In situsectioning techniques and sequential imaging within the SEM allowed three-dimensional tomographic reconstruction of sample morphology. Improvements in the detection and discrimination of backscattered electrons enabled us to identify local precipitation processes with small atomic number contrast. The SEM images were correlated to low-dose and high-sensitivity TEM images, with high-resolution tomography providing unprecedented insight into the structure of nucleating zinc soaps at the molecular level. The correlative approach applied here to study phase separation, and crystallization processes specific to a problem in art conservation creates possibilities for visualization of phase formation in a wide range of soft materials.
The broad X-ray emission of the millisecond pulsar PSR J0437–4715
Authors: Guillot Sebastien
Published: June 2018

The nearest millisecond pulsar PSR J0437–4715 is the ideal target to constrain the dense matter equation of state using the lightcurve modelling method. Our analysis combining XMM-Newton, NuSTAR, and ROSAT observations removed ambiguities in the spectral modelling of the surface emission from PSR J0437–4715. Furthermore, the NuSTAR observation demonstrated that the non-thermal hard tail emission was pulsed at the pulsar spin period. These features are crucial to model the lightcurve and to measure the radius of the neutron star. This conference proceeding is based on the publication Guillot et al. (2016).
Comparing Gamma-ray Loud and Gamma-ray Quiet Radio Pulsars – A Unification Scheme
Authors: Weltevrede Patrick
Published: June 2018

A radio polarization study of gamma-ray-detected pulsars reveals a surprising tendency for the magnetic and rotation axes to be relatively aligned. This provides tension with gamma-ray models, which disfavour such alignment. The lack of correlation between these findings and those derived from the gamma-ray light curves suggests problems in the models. To make the data consistent with a random orientation of the magnetic field the emission regions could be assumed to extend outside what is traditionally thought to be the open-field-line region in a magnetic inclination angle dependent way. Both acceptance and rejection of this hypothesis has important consequences. Finally, a unification scheme is proposed to explain the observational differences between gamma-ray loud and gamma-ray quiet radio pulsars. This unification scheme takes the orientation of the line of sight and the magnetic inclination angle to be key parameters affecting both the radio and gamma-ray light-curve morphology.
PSRSalsa and the bi-drifting pulsar B1839–04
Authors: Weltevrede Patrick
Published: June 2018

PSRSalsa is a versatile open-source pulsar data-analysis project designed to obtain a comprehensive picture of the radio properties of your pulsar of choice. Here its usefulness is demonstrated through the analysis of the radio pulsar B1839–04, thereby revealing the extremely rare phenomenon of “bi-drifting” where the drift direction of subpulses is systematically different in different pulse profile components.
Systematic study of magnetar outbursts
Authors: Zelati Francesco Coti
Published: June 2018

We present the results of a systematic study of all magnetar outbursts observed to date through a reanalysis of data acquired in about 1100 X-ray observations. We track the temporal evolution of the luminosity for all these events, model empirically their decays, and estimate the characteristic decay time-scales and the energy involved. We study the link between different parameters, and reveal several correlations between different quantities. We discuss our results in the framework of the models proposed to explain the triggering mechanism and evolution of magnetar outbursts.
A mechanism of supernova explosion driven by magnetic monopoles
Authors: Peng Qiu-He , Jing-Jing Liu , Chou Chih-Kang
Published: June 2018

Taking Rubakov-Callen effect (that nucleons may decay catalyzed by magnetic monopoles) as the energy source, we propose a unified model of supernova driven by magnetic monopoles in this paper.
Anomalous Pulsar Scattering at LOFAR Frequencies
Authors: Geyer Marisa , Karastergiou Aris
Published: June 2018

The Low Frequency Array (LOFAR) is ideally suited to pulsar scattering studies, providing broad bands at low frequencies where the imprints of the ionized Interstellar Medium (IISM) are exaggerated. We analyse a set of sources at 110–190 MHz, and find unexpectedly shallow dependencies of pulse scatter broadening on frequency. These anomalous scattering values are discussed by considering evidence for anisotropic scattering and small scattering clouds.
Phase shifts in multi-frequency observations of the drift bands of J0034-0721
Authors: McSweeney Samuel J. , Bhat N. D. Ramesh , Tremblay Steven E. , Deshpande Avinash A.
Published: June 2018

We observed single pulses from PSR J0034-0721 (B0031-07) simultaneously at the MWA (185 MHz) and the GMRT (610 MHz). Correlation analyses reveal that the phase difference of the average profiles at the two frequencies differs from the phase difference observed between individual subpulses, indicating that the individual emission columns above the pulsar’s rotating carousel of sparks do not evolve in frequency in the same way that the global magnetosphere does. This hints at a possible departure from the dipolar field geometry in this pulsar’s emission region. Moreover, the discrepancy depends on the drift mode, suggestive of a way to constrain the emission heights associated with each drift mode.
Gigahertz-peaked spectra pulsars
Authors: Rożko Karolina , Lewandowski Wojciech , Kijak Jarosław , Basu Rahul
Published: June 2018

In this short overview we summarize our knowledge of twenty five pulsars showing GPS characteristics. Especially, we will focus on two objects. The first is PSR B1800–21 - a Vela-like GPS pulsar with a variable spectrum. The second is PSR J1740+1000 - a pulsar that shows high frequency turnover based on our most recent observations using the Giant Meterwave Radio Telescope and the Green Bank Telescope.
Searching for pulsars in future radio continuum surveys
Authors: Dai Shi , Johnston Simon , Hobbs George
Published: June 2018

Radio continuum surveys are equally sensitive to all pulsars, not affected by dispersion measure smearing, scattering or orbital modulation of spin periods, and therefore allow us to search for extreme pulsars, such as sub-millisecond pulsars, pulsar-black hole systems and pulsars in the Galactic Centre. As we move towards the Square Kilometre Array (SKA) era, searching for pulsars in continuum images will complement conventional pulsar searches, and make it possible to find extreme objects.
Machine Learning for Pulsar Detection
Authors: McFadden Rebecca , Karastergiou Aris , Roberts Stephen
Published: June 2018

The next generation of radio telescopes will have unprecedented sensitivity and time-resolution offering exciting new capabilities in time-domain science. However, this will result in very large numbers of pulsar and transient event candidates and the associated data rates will be technically challenging in terms of data storage and signal processing. Automated detection and classification techniques are therefore required and must be optimized to allow high-throughput data processing in real time. In this paper we provide a summary of the emerging machine learning techniques being applied to this problem.
Pulsar observations at millimetre wavelengths
Authors: Torne Pablo
Published: June 2018

Detecting and studying pulsars above a few GHz in the radio band is challenging due to the typical faintness of pulsar radio emission, their steep spectra, and the lack of observatories with sufficient sensitivity operating at high frequency ranges. Despite the difficulty, the observations of pulsars at high radio frequencies are valuable because they can help us to understand the radio emission process, complete a census of the Galactic pulsar population, and possibly discover the elusive population in the Galactic Centre, where low-frequency observations have problems due to the strong scattering. During the decades of the 1990s and 2000s, the availability of sensitive instrumentation allowed for the detection of a small sample of pulsars above 10 GHz, and for the first time in the millimetre band. Recently, new attempts between 3 and 1 mm (≈86 − 300 GHz) have resulted in the detections of a pulsar and a magnetar up to the highest radio frequencies to date, reaching 291 GHz (1.03 mm). The efforts continue, and the advent of new or upgraded millimetre facilities like the IRAM 30-m, NOEMA, the LMT, and ALMA, warrants a new era of high-sensitivity millimetre pulsar astronomy in the upcoming years.
Blind Search Methods for Binary Gamma-ray Pulsars
Authors: Nieder Lars , Clark Colin J. , Pletsch Holger J.
Published: June 2018

Gamma-ray observations by the Fermi Large Area Telescope (LAT) have been used very successfully in the last 9 years to detect more than 200 gamma-ray pulsars. Sixty of these have been found by directly searching for pulsations in the gamma-ray data, but only one binary MSP has been found this way. Pulsars in binaries are often difficult to detect in radio data because of large eclipses, and some binary MSPs may even be radio quiet. For those, a gamma-ray blind search might be the only possibility for detection. While searches for isolated pulsars up to kilohertz frequencies are already computationally very challenging, blind searches for binary gamma-ray pulsars are simply infeasible without further knowledge of their orbital parameters. Here we present methods with which we can conduct searches for candidate binary gamma-ray pulsars for which orbital constraints are known from optical observations of a likely companion star. We also highlight some example sources where these methods have been used.
Studying Magnetic Fields using Low-frequency Pulsar Observations
Authors: Sobey C. ,   LOFAR and MWA collaborations
Published: June 2018

Low-frequency polarisation observations of pulsars, facilitated by next-generation radio telescopes, provide powerful probes of astrophysical plasmas that span many orders of magnitude in magnetic field strength and scale: from pulsar magnetospheres to intervening magneto-ionic plasmas including the ISM and the ionosphere. Pulsar magnetospheres with teragauss field strengths can be explored through their numerous emission phenomena across multiple frequencies, the mechanism behind which remains elusive. Precise dispersion and Faraday rotation measurements towards a large number of pulsars probe the three-dimensional large-scale (and eventually small-scale) structure of the Galactic magnetic field, which plays a role in many astrophysical processes, but is not yet well understood, especially towards the Galactic halo. We describe some results and ongoing work from the Low Frequency Array (LOFAR) and the Murchison Widefield Array (MWA) radio telescopes in these areas. These and other pathfinder and precursor telescopes have reinvigorated low-frequency science and build towards the Square Kilometre Array (SKA), which will make significant advancements in studies of astrophysical magnetic fields in the next 50 years.
Single Pulses from the Galactic Center Magnetar with the Very Large Array
Authors: Chatterjee S. , Wharton R. S. , Cordes J. M. , Bower G. C. , Butler B. J. , Deller A. T. , Demorest P. , Lazio T. J. W. , Majid W. A. , Ransom S. M.
Published: June 2018

Phased VLA observations of the Galactic center magnetar J1745-2900 over 8-12 GHz reveal rich single pulse behavior. The average profile is comprised of several distinct components and is fairly stable over day timescales and GHz frequencies. The average profile is dominated by the jitter of relatively narrow pulses. The pulses in each of the four profile components are uncorrelated in phase and amplitude, although the occurrence of pulse components 1 and 2 appear to be correlated. Using a collection of the brightest individual pulses, we verify that the index of the dispersion law is consistent with the expected cold plasma value of 2. The scattering time is weakly constrained, but consistent with previous measurements, while the dispersion measure DM = 1763+3−10 pc cm−3 is lower than previous measurements, which could be a result of time variability in the line-of-sight column density or changing pulse profile shape over time or frequency.
Pulsar science with data from the Large European Array for Pulsars
Authors: McKee James W.
Published: June 2018

The Large European Array for Pulsars (LEAP) is a European Pulsar Timing Array project that combines the Lovell, Effelsberg, Nançay, Sardinia, and Westerbork radio telescopes into a single tied-array, and makes monthly observations of a set of millisecond pulsars (MSPs). The overview of our experiment is presented in Bassa et al. (2016). Baseband data are recorded at a central frequency of 1396 MHz and a bandwidth of 128 MHz at each telescope, and are correlated offline on a cluster at Jodrell Bank Observatory using a purpose-built correlator, detailed in Smits et al. (2017). LEAP offers a substantial increase in sensitivity over that of the individual telescopes, and can operate in timing and imaging modes (notably in observations of the galactic centre radio magnetar; Wucknitz 2015). To date, 4 years of observations have been reduced. Here, we report on the scientific projects which have made use of LEAP data.
Exploiting simultaneous multi-frequency observations to probe polar-cap processes
Authors: Maan Yogesh
Published: June 2018

Sub-pulse drifting has been regarded as one of the most insightful aspects of the pulsar radio emission. The phenomenon is generally explained with a system of emission sub-beams rotating around the magnetic axis, originating from a carousel of sparks near the pulsar surface (the carousel model). Since the observed radio emission at different frequencies is generated at different altitudes in the pulsar magnetosphere, corresponding sampling of the carousel on the polar cap differs slightly in magnetic latitude. When this aspect is considered, it is shown here that the carousel model predicts important observable effects in multi-frequency or wide-band observations. Also presented here are brief mentions of how this aspect can be exploited to probe the electrodynamics in the polar cap by estimating various physical quantities, and correctly interpret various carousel related phenomena, in addition to test the carousel model itself.
The Green Bank North Celestial Cap Pulsar Survey: Status and Future
Authors: Lynch Ryan S.
Published: June 2018

The ongoing Green Bank North Celestial Cap pulsar survey is using the Green Bank Telescope to search for pulsars and transients over 85% of the celestial sphere. The survey has resulted in over 150 new pulsars, among which are high-precision millisecond pulsars, several binary pulsars, including at least one relativistic double neutron star system, nulling pulsars, and several nearby millisecond pulsars. We find no fast radio bursts in the survey to date. We present these results and discuss the future prospects for the survey.
Targeted millisecond pulsar surveys of Fermi γ-ray sources with LOFAR
Authors: Bassa C. G. , Pleunis Z. , Hessels J. W. T. , Ferrara E. C. , Kondratiev V. I. , Sanidas S. , Lyne A. G. , Stappers B. W. , Ransom S. M. ,   the Fermi Pulsar Search Consortium
Published: June 2018

We have used LOFAR to perform targeted millisecond pulsar surveys of Fermi γ-ray sources. Operating at a center frequency of 135 MHz, the surveys use a novel semi-coherent dedispersion approach where coherently dedispersed trials at coarsely separated dispersion measures are incoherently dedispersed at finer steps. Three millisecond pulsars have been discovered as part of these surveys. We describe the LOFAR surveys and the properties of the newly discovered pulsars.
Onset of superconductivity and retention of magnetic fields in cooling neutron stars
Authors: Ho Wynn C. G. , Andersson Nils , Graber Vanessa
Published: June 2018

A superconductor of paired protons is thought to form in the core of neutron stars soon after their birth. Minimum energy conditions suggest that magnetic flux is expelled from the superconducting region due to the Meissner effect, such that the neutron star core retains or is largely devoid of magnetic fields for some nuclear equation of state and proton pairing models. We show via neutron star cooling simulations that the superconducting region expands faster than flux is expected to be expelled because cooling timescales are much shorter than timescales of magnetic field diffusion. Thus magnetic fields remain in the bulk of the neutron star core for at least 106 − 107yr. We estimate the size of flux free regions at 107yr to be ≲ 100m for a magnetic field of 1011G and possibly smaller for stronger field strengths.
Solar System Ephemerides, Pulsar Timing, Gravitational Waves, & Navigation
Authors: Lazio T. Joseph W. , Bhaskaran S. , Cutler C. , Folkner W. M. , Park R. S. , Ellis J. A. , Ely T. , Taylor S. R. , Vallisneri M.
Published: June 2018

In-spiraling supermassive black holes should emit gravitational waves, which would produce characteristic distortions in the time of arrival residuals from millisecond pulsars. Multiple national and regional consortia have constructed pulsar timing arrays by precise timing of different sets of millisecond pulsars. An essential aspect of precision timing is the transfer of the times of arrival to a (quasi-)inertial frame, conventionally the solar system barycenter. The barycenter is determined from the knowledge of the planetary masses and orbits, which has been refined over the past 50 years by multiple spacecraft. Within the North American Nanohertz Observatory for Gravitational Waves (NANOGrav), uncertainties on the solar system barycenter are emerging as an important element of the NANOGrav noise budget. We describe what is known about the solar system barycenter, touch upon how uncertainties in it affect gravitational wave studies with pulsar timing arrays, and consider future trends in spacecraft navigation.
Solar-System Studies with Pulsar Timing Arrays
Authors: Caballero R. N. ,   Collaborators
Published: June 2018

High-precision pulsar timing is central to a wide range of astrophysics and fundamental physics applications. When timing an ensemble of millisecond pulsars in different sky positions, known as a pulsar timing array (PTA), one can search for ultra-low-frequency gravitational waves (GWs) through the spatial correlations that spacetime deformations by passing GWs are predicted to induce on the pulses’ times-of-arrival (TOAs). A pulsar-timing model, requires the use of a solar-system ephemeris (SSE) to properly predict the position of the solar-system barycentre, the (quasi-)inertial frame where all TOAs are referred. Here, I discuss how while errors in SSEs can introduce correlations in the TOAs that may interfere with GW searches, one can make use of PTAs to study the solar system. I discuss work done within the context of the European Pulsar Timing Array and the International Pulsar Timing Array collaborations. These include new updates on the masses of planets from PTA data, first limits on masses of the most massive asteroids, and comparisons between SSEs from independent groups. Finally, I discuss a new approach in setting limits on the masses of unknown bodies in the solar system and calculate mass sensitivity curves for PTA data.
Optical pulsars and polarimetry
Authors: Shearer Andrew , Connor Eoin O’
Published: June 2018

Despite the early optical detection of the Crab pulsar in 1969, optical pulsars have become the poor cousin of the neutron star family. Only five normal pulsars have been observed to pulse in the optical waveband. A further three magnetars/SGRs have been detected in the optical/near IR. Optical pulsars are intrinsically faint with a first order luminosity, predicted by Pacini, to be proportional to P−10, where P is the pulsar’s period. Consequently they require both large telescopes, generally over-subscribed, and long exposure times, generally difficult to get. However optical observations have the benefit that polarisation and spectral observations are possible compared to X-ray and gamma-ray observations where polarisation measurements are limited. Over the next decade the number of optical pulsars should increase as optical detectors approach 100% quantum efficiency and as we move into the era of extremely large telescopes where limiting fluxes will be 30 to 100 times fainter compared to existing optical telescopes.
Evolution of the low-frequency pulse profile of PSR B2217+47
Authors: Michilli D. , Hessels J. W. T. , Donner J. Y. , Grießmeier J.-M. , Serylak M. , Shaw B. , Stappers B. W. , Verbiest J. P. W. , Deller A. T. , Driessen L. N. , Stinebring D. R. , Bondonneau L. , Geyer M. , Hoeft M. , Karastergiou A. , Kramer M. , Osłowski S. , Pilia M. , Sanidas S. , Weltevrede P.
Published: June 2018

An evolution of the low-frequency pulse profile of PSR B2217+47 is observed during a six-year observing campaign with the LOFAR telescope at 150 MHz. The evolution is manifested as a new component in the profile trailing the main peak. The leading part of the profile, including a newly-observed weak component, is steady during the campaign. The transient component is not visible in simultaneous observations at 1500 MHz using the Lovell telescope, implying a chromatic effect. A variation in the dispersion measure of the source is detected in the same timespan. Precession of the pulsar and changes in the magnetosphere are investigated to explain the profile evolution. However, the listed properties favour a model based on turbulence in the interstellar medium (ISM). This interpretation is confirmed by a strong correlation between the intensity of the transient component and main peak in single pulses. Since PSR B2217+47 is the fourth brightest pulsar visible to LOFAR, we speculate that ISM-induced pulse profile evolution might be relatively common but subtle and that SKA-Low will detect many similar examples. In this scenario, similar studies of pulse profile evolution could be used in parallel with scintillation arcs to characterize the properties of the ISM.
LOFAR observations of the mode-switching pulsar B0943+10
Authors: Bilous Anna V.
Published: June 2018

PSR B0943+10 is an old non-recycled pulsar which for decades has been mostly known for its rapid and spontaneous radio mode switching. Recently, Hermsen et al. (2013) discovered correlated changes in the thermal X-ray emission from the polar cap, thus demonstrating that radio modes are not just a product of the local changes in the radio emission region, but a sign of some global magnetospheric transformation. At about the same time, owing to the commissioning of the new generation of low-frequency radio arrays, the broadband observations at the lowest edge of ionospheric transparency window became available. At these radio frequencies profile morphology and the single-pulse properties of PSR B0943+10’s emission become very dynamic, providing details not only about the emission itself, but also about the conditions in the polar gap. Here, I will present the recent results of the LOFAR observations of PSR B0943+10 and discuss their contribution to the multiwavelength picture.
A decade of transitional millisecond pulsars
Authors: Jaodand Amruta , Hessels Jason W. T. , Archibald Anne
Published: June 2018

Transitional millisecond pulsars (tMSPs), which are systems that harbor a pulsar in the throes of the recycling process, have emerged as a new source class since the discovery of the first such system a decade ago. These systems switch between accretion-powered low-mass X-ray binary (LMXB) and rotation-powered radio millisecond pulsar (RMSP) states, and provide exciting avenues to understand the physical processes that spin-up neutron stars to millisecond periods. During the last decade, three tMSPs, as well as a candidate source, have been extensively probed using systematic, multi-wavelength campaigns. Here we review the observational highlights from these campaigns and our general understanding of tMSPs.
The Future of Pulsar Research and Facilities
Authors: Bailes Matthew
Published: June 2018

Radio pulsars have been responsible for many astonishing astrophysical and fundamental physics breakthroughs since their discovery 50 years ago. In this review I will discuss many of the highlights, most of which were only possible because of the provision of large-scale observing facilities. The next 50 years of pulsar astronomy can be very bright, but only if our governments properly plan and fund the infrastructure necessary to enable future discoveries. Being a small sub-field of astronomy places an onus on the pulsar community to have an open-source/open access approach to data, software, and major observing facilities to enable new groups to emerge to keep the field vibrant.
Willingness to pay for improved public health care services in Saudi Arabia: a contingent valuation study among heads of Saudi households
Authors: Al-Hanawi Mohammed K. , Alsharqi Omar , Vaidya Kirit
Published: June 2018

The bulk of health care service provision in Saudi Arabia is undertaken by the public health care sector through the Ministry of Health, which is funded annually by the total government budget, which, in turn, is derived primarily from oil revenue. Public health care services in Saudi Arabia are characterised by an overload, overuse, and shortage of medical personnel, which can result in dissatisfaction with the quality of the current public health care services. This study uses a contingent valuation method to investigate the willingness of Saudi people to pay for improvements to the quality of public health care services. This study also determines the association between the willingness to pay for quality improvements and respondents’ demographic and socioeconomic characteristics. A pre-tested interviewer-administered questionnaire was used to collect data from 1187 heads of household in Jeddah Province over a five-month period. Multi-stage sampling was employed to recruit participants. Partial Tobit regression and corresponding marginal effects analyses were used to analyse the data. These empirical analyses show that the majority of the sample was willing to pay for quality improvements in the public health care services. The results of this study might be of use to policymakers to help with both priority setting and fund allocation.
Patientenbezogene Komplexität in der Pflege – Kollektive Case Studies im Akutspital
Authors: Gurtner Caroline , Spirig Rebecca , Staudacher Diana , Huber Evelyn
Published: June 2018

Zusammenfassung. Hintergrund: Die patientenbezogene Komplexität der Pflege ist durch die Merkmale „Instabilität“, „Unsicherheit“ und „Variabilität“ definiert. Aufgrund der reduzierten Aufenthaltsdauer und der steigenden Zahl chronisch und mehrfach erkrankter Personen erhöht sich die Komplexität der Pflege. Ziel: In dieser Studie untersuchten wir das Phänomen patientenbezogener Komplexität aus Sicht von Pflegefachpersonen und Pflegeexpertinnen im Akutspital. Methode: Im Rahmen eines kollektiven Case-Study-Designs schätzten Pflegefachpersonen und Pflegeexpertinnen die Komplexität von Pflegesituationen mit einem Fragebogen ein. Danach befragten wir sie in Einzelinterviews zu ihrer Einschätzung. Mittels Within-Case-Analyse verdichteten wir die Daten induktiv zu Fallgeschichten. In der Cross-Case-Analyse verglichen wir die Fallgeschichten hinsichtlich deduktiv abgeleiteter Merkmale. Ergebnisse: Die Ausprägung der Komplexität hing in den vier Cases im Wesentlichen davon ab, ob klinische Probleme kontrollierbar und prognostizierbar waren. Je nach individuellen Ressourcen der Patientinnen und Patienten stieg bzw. sank die Komplexität. Schlussfolgerungen: Komplexe Patientensituationen fordern von Pflegefachpersonen Fachwissen, Erfahrung, kommunikative Kompetenzen sowie die Fähigkeit zur Reflexion. Berufsanfänger und Berufsanfängerinnen werden zur Entwicklung dieser Fähigkeiten idealerweise durch erfahrene Berufskolleginnen oder -kollegen unterstützt und beraten.
A Comparative Study of ULF Waves' Role in the Dynamics of Charged Particles in the Plasmasphere: Van Allen Probes Observation
Authors: Ren Jie , Zong Q. G. , Miyoshi Y. , Rankin R. , Spence H. E. , Funsten H. O. , Wygant J. R. , Kletzing C. A.
Published: June 2018

By analyzing observations from Van Allen Probes in its inbound and outbound orbits, we present evidence of coherent enhancement of cold plasmaspheric electrons and ions due to drift‐bounce resonance with ultralow frequency (ULF) waves. From 18:00 UT on 28 May 2017 to 10:00 UT on 29 May 2017, newly formed poloidal mode standing ULF waves with significant electric field oscillations were observed in two consecutive orbits when Probe B was traveling inbound. In contrast to observations during outbound orbits, the cold (<150 eV) electrons measured by the HOPE instrument were characterized by flux enhancements several times larger and bidirectional pitch angle distributions during inbound orbits. The electron number density inferred from upper hybrid waves is twice as larger as during inbound orbits, which were also confirmed by an increase of spacecraft potential. The observed ULF waves are identified as second harmonic modes that satisfy the drift‐bounce resonant condition of N = 1 with cold electrons. An enhancement of the plasmaspheric ion number density to restore charge neutrality of plasmas in inbound orbits is observed, which is associated with an increase of ULF wave periods. The observations suggest that the dynamics of plasmaspheric electrons is modified by ULF waves through drift‐bounce resonance and that plasmaspheric ions are indirectly impacted.
The Martian Magnetosphere: Areas of Unsettled Terminology
Authors: Espley Jared R.
Published: June 2018

The near‐Mars space environment has a number of regions and boundaries that have numerous and confusing labels. The whole region is sometimes referred to as the induced Martian magnetosphere and sometimes as the solar wind interaction with Mars. The middle boundary where the shocked solar wind plasma gives way to predominately planetary‐derived plasma has a variety of names. The region below that middle boundary and the top of the ionosphere also does not have a uniformly used name. There are several other regions and boundaries that also have naming confusion. The various terms that are currently used in the literature for these subjects are identified and discussed; regions and boundaries that have well‐settled names are not discussed nor are the details of the physics involved.
EISCAT Observation of Wave‐Like Fluctuations in Vertical Velocity of Polar Mesospheric Summer Echoes Associated With a Geomagnetic Disturbance
Authors: Lee Young‐Sook , Kim Yong Ha , Kim Kyung‐Chan , Kwak Young‐Sil , Sergienko Timothy , Kirkwood Sheila , Johnsen Magnar G.
Published: June 2018

By analyzing a data set from the European Incoherent SCATter (EISCAT) Very High Frequency (VHF) radar at Tromsø, we find that both radar reflectivity and upward ion velocity in a polar mesospheric summer echo (PMSE) layer simultaneously increased at the commencement of a local geomagnetic disturbance, which occurred at midnight on 9 July 2013. The onset of the upward velocity was followed by periodic repetition of ~5 min during the initial 30‐min stage, and then at later stage the vertical velocity oscillated with ~7‐ and ~20‐min periodicities at 85‐ to 90‐km altitudes. The ~5‐min periodicity is close to the buoyancy period, and the ~7‐ and ~20 min periodicities are consistent with gravity waves, thus suggesting that gravity waves can be generated by the effects of the geomagnetic disturbance. On the other hand, the variation of PMSE intensity (85–90 km) was in phase with fluctuations of electron densities (90–110 km) with ~12‐ and ~13‐min periodicities at the initial and later stages, respectively. The initial creation of PMSE can be attributed to both the sudden onset of particle precipitation and ice particles produced by adiabatic cooling during the rapid updraft, as detected by large upward velocity. Our periodogram analysis suggests that variations of PMSE intensity seem to follow the same periods with E region electron density, which is moduled by energetic electron precipitation, while vertical velocity oscillates at atmospheric gravity wave periods.
Control of PD-L1 expression by miR-140/142/340/383 and oncogenic activation of the OCT4–miR-18a pathway in cervical cancer
Authors: Dong Peixin , Xiong Ying , Yu Jiehai , Chen Lin , Tao Tang , Yi Song , Hanley Sharon J. B. , Yue Junming , Watari Hidemichi , Sakuragi Noriaki
Published: May 2018

PD-L1, a key inhibitory immune receptor, has crucial functions in cancer immune evasion, but whether PD-L1 promotes the malignant properties of cervical cancer (CC) cells and the mechanism by which PD-L1 is regulated in CC remains unclear. We report that PD-L1 is overexpressed in CC, and shRNA-mediated PD-L1 depletion suppresses the proliferation, invasion, and tumorigenesis of CC cells. Loss of miR-140/142/340/383 contributes to PD-L1 upregulation. miR-18a enhances PD-L1 levels by targeting PTEN, WNK2 (ERK1/2 pathway inhibitor), and SOX6 (Wnt/β-catenin pathway inhibitor and p53 pathway activator) to activate the PI3K/AKT, MEK/ERK, and Wnt/β-catenin pathways and inhibit the p53 pathway, and miR-18a also directly suppresses the expression of the tumor suppressors BTG3 and RBSP3 (CTDSPL). miR-18a overexpression in CC cells is triggered by OCT4 overexpression. Our data implicate PD-L1 as a novel oncoprotein and indicate that miR-140/142/340/383 and miR-18a are key upstream regulators of PD-L1 and potential targets for CC treatment.
Prognostic role of carcinoembryonic antigen and carbohydrate antigen 19-9 in metastatic colorectal cancer: a BRAF-mutant subset with high CA 19-9 level and poor outcome
Authors: Thomsen Maria , Skovlund Eva , Sorbye Halfdan , Bolstad Nils , Nustad Kjell Johannes , Glimelius Bengt , Pfeiffer Per , Kure Elin H. , Johansen Julia S. , Tveit Kjell Magne , Christoffersen Thoralf , Guren Tormod Kyrre
Published: June 2018

Background

Mutation status of RAS and BRAF, as well as serum levels of carcinoembryonic antigen (CEA) and carbohydrate antigen 19-9 (CA 19-9), are biomarkers used in clinical management of patients with gastrointestinal cancers. This study aimed to examine the prognostic role of these biomarkers in a patient population that started first-line chemotherapy for unresectable metastatic colorectal cancer (mCRC) in the NORDIC-VII study.

Methods

CEA and CA 19-9 were measured in serum samples from 545 patients obtained before the start of chemotherapy. Four hundred and ninety-four patients had detectable levels of carbohydrate antigen 19-9 (CA 19-9). RAS (exons 2–4) and BRAF (V600E) mutation status were available from 440 patients. Overall survival (OS) was estimated in patient groups defined by serum CEA or CA 19-9 levels using cut-off values of 5 µg/L and 35 kU/L, respectively, in the total population and in subgroups according to RAS and BRAF mutation status.

Results

For both CEA and CA 19-9, elevated serum levels were associated with reduced OS in adjusted analyses which included RAS and BRAF mutation status, baseline World Health Organization performance status, and levels of alkaline phosphatase and C-reactive protein. The negative prognostic information provided by an elevated CA 19-9 level was particularly marked in patients with BRAF mutation (hazard ratio = 4.35, interaction P = 0.003, in an adjusted model for OS).

Conclusions

High baseline serum concentrations of CEA and CA 19-9 provide independent information of impaired prognosis in mCRC. In patients with BRAF-mutant tumours, elevated serum CA 19-9 may identify a subgroup with highly aggressive disease and could contribute to improving therapeutic decisions.
Programming for increased expression of hippocampal GAD67 mediated the hypersensitivity of the hypothalamic–pituitary–adrenal axis in male offspring rats with prenatal ethanol exposure
Authors: Lu Juan , Jiao Zhexiao , Yu Ying , Zhang Chong , He Xia , Li Qiang , Xu Dan , Wang Hui
Published: May 2018

An imbalance of excitatory and inhibitory signals in the brain has been proposed to be one of the main pathological features of various diseases related to hypothalamic–pituitary–adrenal axis (HPAA) dysfunction. Excessive glutamate release induces neuronal excitotoxicity, while glutamic acid decarboxylase (GAD) 67 promotes the transformation of excessive glutamate to γ-aminobutyric acid (GABA). Our previous studies demonstrated that prenatal ethanol exposure (PEE) causes foetal over-exposure to maternal corticosterone and hypersensitivity of the HPAA after birth, but its intrauterine programming mechanism is unknown. In this study, PEE was shown to lead to an enhanced potential excitatory ability of the hypothalamus and hypersensitivity of the HPAA, as well as mild abnormal hippocampal morphology, demethylation of the -1019 to -691-bp region in the hippocampal GAD67 promoter and upregulation of GAD67 expression accompanied by a reduction in glutamatergic neurons and increase in GABAergic neurons in PEE male offspring. Similar changes were also found in PEE male foetal rats. Furthermore, corticosterone increased the expression of the glucocorticoid receptor (GR) and GAD67 in foetal hippocampal H19-7 cells in a concentration-dependent manner, accompanied by demethylation of the GAD67 promoter, a decrease in glutamatergic neurons and increase in GABAergic neurons. The GR inhibitor, mifepristone, reversed the effects of corticosterone on H19-7 cells. These results suggested that PEE-induced excessive corticosterone can lead to upregulation of GAD67 through epigenetic modification mediated by the GR in the male foetal hippocampus, thereby weakening the negative regulation of the HPAA by the hippocampus and increasing the potential excitatory ability of the hypothalamus. These changes persisted until after birth, resulting in hypersensitivity of the HPAA. However, gender differences were observed in the hippocampal development, morphology and GAD67 expression associated with PEE. Programming for the increased expression of hippocampal GAD67 is a potential mechanism responsible for the hypersensitivity of the HPAA in PEE male rats.
RAGE-dependent mitochondria pathway: a novel target of silibinin against apoptosis of osteoblastic cells induced by advanced glycation end products
Authors: Mao Y. X. , Cai W. J. , Sun X. Y. , Dai P. P. , Li X. M. , Wang Q. , Huang X. L. , He B. , Wang P. P. , Wu G. , Ma J. F. , Huang S. B.
Published: June 2018

Advanced glycation end products (AGEs) can stimulate osteoblast apoptosis and have a critical role in the pathophysiology of diabetic osteoporosis. Mitochondrial abnormalities are closely related to osteoblast dysfunction. However, it remains unclear whether mitochondrial abnormalities are involved in AGE-induced osteoblastic cell apoptosis. Silibinin, a major flavonolignan compound of silimarin, has strong antioxidant and mitochondria-protective properties. In the present study, we explored the possible mitochondrial mechanisms underlying AGE-induced apoptosis of osteoblastic cells and the effect of silibinin on osteoblastic cell apoptosis. We demonstrated that mitochondrial abnormalities largely contributed to AGE-induced apoptosis of osteoblastic cells, as evidenced by enhanced mitochondrial oxidative stress, conspicuous reduction in mitochondrial membrane potential and adenosine triphosphate production, abnormal mitochondrial morphology, and altered mitochondrial dynamics. These AGE-induced mitochondrial abnormalities were mainly mediated by the receptor of AGEs (RAGE). In addition, we found that silibinin directly downregulated the expression of RAGE and modulated RAGE-mediated mitochondrial pathways, thereby preventing AGE-induced apoptosis of osteoblastic cells. This study not only provides a new insight into the mitochondrial mechanisms underlying AGE-induced osteoblastic cell apoptosis, but also lays a foundation for the clinical use of silibinin for the prevention or treatment of diabetic osteoporosis.