Measurement of e^{+}e^{-} Momentum and Angular Distributions from Linearly Polarized Photon Collisions

The Breit-Wheeler process which produces matter and antimatter from photon collisions is experimentally investigated through the observation of 6085 exclusive electron-positron pairs in ultraperipheral Au+Au collisions at sqrt[s_{NN}]=200  GeV. The measurements reveal a large fourth-order angular modulation of cos4Δϕ=(16.8±2.5)% and smooth invariant mass distribution absent of vector mesons (ϕ, ω, and ρ) at the experimental limit of ≤0.2% of the observed yields. The differential cross section as a function of e^{+}e^{-} pair transverse momentum P_{⊥} peaks at low value with sqrt[⟨P_{⊥}^{2}⟩]=38.1±0.9  MeV and displays a significant centrality dependence. These features are consistent with QED calculations for the collision of linearly polarized photons quantized from the extremely strong electromagnetic fields generated by the highly charged Au nuclei at ultrarelativistic speed. The experimental results have implications for vacuum birefringence and for mapping the magnetic field which is important for emergent QCD phenomena.

Hydroxyurea treatment and neurocognitive functioning in sickle cell disease from school age to young adulthood

Neurocognitive impairment is common in sickle cell disease (SCD) and is associated with significant functional limitations. In a cross-sectional analysis, we examined the association between hydroxyurea (HU) treatment and neurocognitive functioning from school-age to young adulthood in individuals with SCD. A total of 215 patients with HbSS/HbSβ⁰ -thalassaemia (71% HU treated) and 149 patients with HbSC/HbSβ⁺ -thalassaemia (20% HU treated) completed neurocognitive measures at one of four developmental stages: school-age (age 8-9 years), early adolescence (age 12-13 years), late adolescence (age 16-17 years) and young adulthood (ages 19-24 years). For participants with multiple assessments, only the most recent evaluation was included. In multivariable analysis adjusted for social vulnerability, HU treatment and sex, older age was associated with a reduction in overall intelligence quotient (IQ) of 0·55 points per year of life [standard error (SE) = 0·18, false discovery rate adjusted P value (PFDR) = 0.01] for patients with HbSS/HbSβ⁰ -thalassaemia. Earlier initiation of HU (n = 152) in HbSS/HbSβ⁰ -thalassaemia was associated with higher scores on neurocognitive measures across most domains, including IQ [estimate (SE) 0·77 (0·25)/year, PFDR = 0·01], after adjusting for social vulnerability, sex and treatment duration. These results support the early use of HU to limit the detrimental neurocognitive effects of SCD, while highlighting the need for additional measures to further mitigate neurocognitive deterioration.

Global Polarization of Ξ and Ω Hyperons in Au+Au Collisions at sqrt[s_{NN}]=200 GeV

Global polarization of Ξ and Ω hyperons has been measured for the first time in Au+Au collisions at sqrt[s_{NN}]=200  GeV. The measurements of the Ξ^{-} and Ξ[over ¯]^{+} hyperon polarization have been performed by two independent methods, via analysis of the angular distribution of the daughter particles in the parity violating weak decay Ξ→Λ+π, as well as by measuring the polarization of the daughter Λ hyperon, polarized via polarization transfer from its parent. The polarization, obtained by combining the results from the two methods and averaged over Ξ^{-} and Ξ[over ¯]^{+}, is measured to be ⟨P_{Ξ}⟩=0.47±0.10(stat)±0.23(syst)% for the collision centrality 20%-80%. The ⟨P_{Ξ}⟩ is found to be slightly larger than the inclusive Λ polarization and in reasonable agreement with a multiphase transport model. The ⟨P_{Ξ}⟩ is found to follow the centrality dependence of the vorticity predicted in the model, increasing toward more peripheral collisions. The global polarization of Ω, ⟨P_{Ω}⟩=1.11±0.87(stat)±1.97(syst)% was obtained by measuring the polarization of daughter Λ in the decay Ω→Λ+K, assuming the polarization transfer factor C_{ΩΛ}=1.

Nonmonotonic Energy Dependence of Net-Proton Number Fluctuations

Nonmonotonic variation with collision energy (sqrt[s_{NN}]) of the moments of the net-baryon number distribution in heavy-ion collisions, related to the correlation length and the susceptibilities of the system, is suggested as a signature for the quantum chromodynamics critical point. We report the first evidence of a nonmonotonic variation in the kurtosis times variance of the net-proton number (proxy for net-baryon number) distribution as a function of sqrt[s_{NN}] with 3.1  σ significance for head-on (central) gold-on-gold (Au+Au) collisions measured solenoidal tracker at Relativistic Heavy Ion Collider. Data in noncentral Au+Au collisions and models of heavy-ion collisions without a critical point show a monotonic variation as a function of sqrt[s_{NN}].

An investigation of recommended serve food portions and attaining energy and protein requirements in older adults living in residential care

BACKGROUND

Ageing populations show a propensity for reduced food intake, which impacts nutritional adequacy. Nutrition guidelines for residential care homes (RCHs) are currently based on serve size of core food groups and do not consider nutrient density. The present study aimed to investigate the weight of foods served/consumed compared to recommended serve sizes and to compare energy and protein intake with individual requirements.

METHODS

This was an observational study of older adults living in four RCHs. Dietary intake was estimated through the difference between weighed reference meals and a single, double-weighed 24-h food plate waste collected from each participant. FoodWorks9^® (Xyris^® Software, Brisbane, Australia) was used to calculate energy, protein and serves of core food groups from food intake and the menu provided to recommended serve sizes. Individual intake was compared with nutrition guidelines and estimated energy and protein requirements.

RESULTS

Across 420 participants, 9.8% completed a main meal (lunch or dinner). The servings provided [248 g; interquartile range (IQR) = 206-290 g] were less than the recommended servings for a main meal (306 g = protein/starch/two vegetables), with 157 g (IQR = 109-221 g) consumed. The menu provided for minimum serves of all core food groups except for dairy. Median energy intake (n = 389) (5272 kJ day^-1 , IQR = 4229-6720 kJ) and protein intake (47.3 g day^-1 , IQR = 35.9-60.8 g) were less than estimated requirements (8181 kJ day^-1 , IQR = 7300-9338 kJ day^-1 ; 76.7 g day^-1 , IQR = 66.7-90.8 g).

CONCLUSIONS

Nutritional needs were not met in this cohort. The findings of the present study highlight the need for smaller, nutrient-dense meals and revised menu standards to ensure nutritional adequacy in this vulnerable population.

Salt bridges govern the structural heterogeneity of heme protein interactions and porphyrin networks: microperoxidase-11

In this work, a proteolytic digest of cytochrome c (microperoxidase 11, MP-11) was used as a model to study the structural aspects of heme protein interactions and porphyrin networks. The MP-11 structural heterogeneity was studied as a function of the starting pH (e.g., pH 3.1-6.1) and concentration (e.g., 1-50 μM) conditions and adduct coordination. Trapped ion mobility spectrometry coupled to mass spectrometry (TIMS-MS) showed the MP-11 structural dependence of the charge state distribution and molecular ion forms with the starting pH conditions. The singly charged (e.g., [M]+, [M - 2H + NH4]+, [M - H + Na]+ and [M - H + K]+) and doubly charged (e.g., [M + H]2+, [M - H + NH4]2+, [M + Na]2+ and [M + K]2+) molecular ion forms were observed for all solvent conditions, although the structural heterogeneity (e.g., number of mobility bands) significantly varied with the pH value and ion form. The MP-11 dimer formation as a model for heme-protein protein interactions showed that dimer formation is favored toward more neutral pH and favored when assisted by salt bridges (e.g., NH4 +, Na+ and K+ vs. H+). Inspection of the dimer mobility profiles (2+ and 3+ charge states) showed a high degree of structural heterogeneity as a function of the solution pH and ion form; the observation of common mobility bands suggest that the different salt bridges can stabilize similar structural motifs. In addition, the salt bridge influence on the MP-11 dimer formations was measured using collision induced dissociation and showed a strong dependence with the type of salt bridge (i.e., a CE50 of 10.0, 11.5, 11.8 and 13.0 eV was observed for [2M + H]3+, [2M - H + NH4]3+, [2M + Na]3+ and [2M + K]3+, respectively). Measurements of the dimer equilibrium constant showed that the salt bridge interactions increase the binding strength of the dimeric species.

Do images of dietitians on the Internet reflect the profession?

BACKGROUND

The image of dietitians presented on the Internet shapes public perception of the profession, which in turn may influence engagement with professionals. The aim was to describe the portrayal of the dietetic profession on the Internet and how this aligns with international professional demographics.

METHODS

In this cross-sectional observational study, images appearing in two Google image searches using the word 'dietitian' were analysed for content by two independent researchers. A coding framework was used to identify personal characteristics of professionals and others presented in the image, as well as the work setting. These were compared to demographic data of members of professional associations in Australia, the United Kingdom (UK) and the United States of America (USA).

RESULTS

The dietitian portrayed in the images (n = 339) was most often female (88%), Caucasian (72%), aged between 26-39 years (63%), pictured alone (78%), pictured with food (78%) and in a setting that could not be determined (76%). The age and gender profile presented matches the characteristics of the international workforce; however, there was an absence of images illustrating dietitians in authentic work roles.

CONCLUSIONS

The images resulting from an online search for 'dietitian' do not fully illustrate the profession. There are opportunities to create and share authentic images online that show the breadth of work roles and diversity of professionals' age, gender, cultural background and size.

First Measurement of Λ_{c} Baryon Production in Au+Au Collisions at sqrt[s_{NN}]=200 GeV

We report on the first measurement of the charmed baryon Λ_{c}^{±} production at midrapidity (|y|<1) in Au+Au collisions at sqrt[s_{NN}]=200  GeV collected by the STAR experiment at the Relativistic Heavy Ion Collider. The Λ_{c}/D^{0} [denoting (Λ_{c}^{+}+Λ_{c}^{-})/(D^{0}+D[over ¯]^{0})] yield ratio is measured to be 1.08±0.16  (stat)±0.26  (sys) in the 0%-20% most central Au+Au collisions for the transverse momentum (p_{T}) range 3<p_{T}<6  GeV/c. This is significantly larger than the pythia model calculations for p+p collisions. The measured Λ_{c}/D^{0} ratio, as a function of p_{T} and collision centrality, is comparable to the baryon-to-meson ratios for light and strange hadrons in Au+Au collisions. Model calculations including coalescence hadronization for charmed baryon and meson formation reproduce the features of our measured Λ_{c}/D^{0} ratio.

Paediatric to adult transition care for patients with sickle cell disease: a global perspective

Sickle cell disease is a life-threatening inherited condition designated as a public health priority by WHO. Increased longevity of patients with sickle cell disease in high-income, middle-income, and low-income countries present unprecedented challenges for all settings; however, a globally standardised solution for patient transition from paediatric to adult sickle cell disease health care is unlikely to address the challenges. We established a task force of experts from a multicountry (the USA, Europe, Middle East, and Africa) consortium. We combined themes from the literature with viewpoints from members of the task force and invited experts to provide a global overview of transition care practice, highlighting barriers to effective transition care and provide baseline recommendations that can be adapted to local needs. We highlighted priorities to consider for any young person with sickle cell disease transitioning from paediatric to adult health care: skills transfer, increasing self-efficacy, coordination, knowledge transfer, linking to adult services, and evaluating readiness (the SICKLE recommendations). These recommendations aim to ensure appropriate benchmarking of transition programming, but multisite prospective studies are needed to address this growing public health need.

Physics Data Production on HPC: Experience to be efficiently running at scale

The Solenoidal Tracker at RHIC (STAR) is a multi-national supported experiment located at the Brookhaven National Lab and is currently the only remaining running experiment at RHIC. The raw physics data captured from the detector is on the order of tens of PBytes per data acquisition campaign, making STAR fit well within the definition of a big data science experiment. The production of the data has typically run using a High Throughput Computing (HTC) approach either done on a local farm or via Grid computing resources. Especially, all embedding simulations (complex workflow mixing real and simulated events) have been run on standard Linux resources at NERSC’s Parallel Distributed Systems Facility (PDSF). However, as per April 2019 PDSF has been retired and High Performance Computing (HPC) resources such as the Cray XC-40 Supercomputer known as “Cori” have become available for STAR’s data production as well as embedding. STAR has been the very first experiment to show feasibility of running a sustainable data production campaign on this computing resource. In this contribution, we hope to share with the community the best practices for using such resource efficiently. The use of Docker containers with Shifter is the standard approach to run on HPC at NERSC – this approach encapsulates the environment in which a standard STAR workflow runs. From the deployment of a tailored Scientific Linux environment (with the set of libraries and special configurations required for STAR to run) to the deployment of third-party software and the STAR specific software stack, we’ve learned it has become impractical to rely on a set of containers comprising each specific software release. To this extent, a solution based on the CernVM File System (CVMFS) for the deployment of software and services has been deployed but it doesn’t stop there. One needs to make careful scalability considerations when using a resource like Cori, such as avoiding metadata lookups, scalability of distributed filesystems, and real limitations of containerized environments on HPC. Additionally, CVMFS clients are not compatible on Cori nodes and one needs to rely on an indirect NFS mount scheme using custom services known as DVS servers designed to forward data to worker nodes. In our contribution, we will discuss our strategies from the past and our current solution based on CVMFS. The second focus of our presentation will be to discuss strategies to find the most efficient use of database Shifter containers serving our data production (a near “database as a service” approach) and the best methods to test and scale your workflow efficiently.

Vibroequilibria in microgravity: Comparison of experiments and theory

Experiments on vibrated fluids confined in cylindrical and cuboidal containers were performed under the reduced gravity conditions of a parabolic flight. The results constitute a systematic quantitative investigation of the vibroequilibria effect, which refers to the reorientation of vibrated fluids in response to the inhomogeneous oscillatory velocity field and the accompanying dynamic pressure. This effect is amplified in microgravity where the restoring force of gravity is small or absent. Here the vibrations are transmitted via a pair of piezoelectric ceramics and a cantilever beam, excited in a resonant mode. The first and second resonances exhibit different types of motion and lead to different types of vibroequilibria surfaces, one with a dip or crater in the interior and the other flattened compared to the unforced reference experiment. The general tendency for interfaces to orient more perpendicular, on average, to the vibrational axis is confirmed. In the case of water in a cuboidal container, a quantitative comparison is made with vibroequilibria theory and with direct simulations of the Navier-Stokes equations. The good agreement confirms the predictions of vibroequilibria theory and suggests the capacity of this phenomenon to manipulate and position fluids in space environments through the choice of frequency and resonant mode.

First Observation of the Directed Flow of D^{0} and D^{0}[over ¯] in Au+Au Collisions at sqrt[s_{NN}]=200 GeV

We report the first measurement of rapidity-odd directed flow (v_{1}) for D^{0} and D^{0}[over ¯] mesons at midrapidity (|y|<0.8) in Au+Au collisions at sqrt[s_{NN}]=200  GeV using the STAR detector at the Relativistic Heavy Ion Collider. In 10-80% Au+Au collisions, the slope of the v_{1} rapidity dependence (dv_{1}/dy), averaged over D^{0} and D^{0}[over ¯] mesons, is -0.080±0.017(stat)±0.016(syst) for transverse momentum p_{T} above 1.5  GeV/c. The absolute value of D^{0} meson dv_{1}/dy is about 25 times larger than that for charged kaons, with 3.4σ significance. These data give a unique insight into the initial tilt of the produced matter, and offer constraints on the geometric and transport parameters of the hot QCD medium created in relativistic heavy-ion collisions.

Risks associated with oral deferiprone in the treatment of infratentorial superficial siderosis

Objective

Deferiprone is an iron chelator that has recently been used to treat patients with infratentorial superficial siderosis (iSS). It is considered to have a generally favourable safety profile but concerns have been raised due to the risk of agranulocytosis. We aimed to evaluate the safety and tolerability of oral deferiprone as a treatment for patients with iSS.

Methods

We present a case series of 10 consecutive patients presenting with classical iSS treated with deferiprone.

Results

Ten patients were followed up for a mean period of 2.3 years (range 0.5–5.5 years). Four patients (40%) were withdrawn from treatment because of treatment-related side effects. The reasons for treatment discontinuation were neutropenic sepsis (n = 3) and fatigue (n = 1). In 2 out of the 3 cases of neutropenic sepsis, patients initially developed neutropenia without sepsis. The mean time to neutropenic sepsis following deferiprone was 1.2 years (range 0.3–2.5) with mean neutrophil count of 0.4 (range 0.3–0.5). Six patients (60%) reported no change in neurological function while on treatment, and four patients (40%) reported that their condition deteriorated.

Conclusions

Deferiprone was poorly tolerated, with 40% of patients withdrawing from treatment, most commonly due to neutropenic sepsis, after an average of 2 years on treatment. This study increases the number of reported cases of agranulocytosis in patients with iSS treated with deferiprone. Clinicians treating iSS patients with deferiprone should be aware that this drug has a potentially life-threatening side effect of neutropenic sepsis, and should ensure that appropriate haematological monitoring is in place.

Polarization of Λ (Λ[over ¯]) Hyperons along the Beam Direction in Au+Au Collisions at sqrt[s_{NN}]=200 GeV

The Λ (Λ[over ¯]) hyperon polarization along the beam direction has been measured in Au+Au collisions at sqrt[s_{NN}]=200  GeV, for the first time in heavy-ion collisions. The polarization dependence on the hyperons' emission angle relative to the elliptic flow plane exhibits a second harmonic sine modulation, indicating a quadrupole pattern of the vorticity component along the beam direction, expected due to elliptic flow. The polarization is found to increase in more peripheral collisions, and shows no strong transverse momentum (p_{T}) dependence at p_{T} greater than 1  GeV/c. The magnitude of the signal is about 5 times smaller than those predicted by hydrodynamic and multiphase transport models; the observed phase of the emission angle dependence is also opposite to these model predictions. In contrast, the kinematic vorticity calculations in the blast-wave model tuned to reproduce particle spectra, elliptic flow, and the azimuthal dependence of the Gaussian source radii measured with the Hanbury Brown-Twiss intensity interferometry technique reproduce well the modulation phase measured in the data and capture the centrality and transverse momentum dependence of the polarization signal.

Observation of Excess J/ψ Yield at Very Low Transverse Momenta in Au+Au Collisions at sqrt[s_{NN}]=200 GeV and U+U Collisions at sqrt[s_{NN}]=193 GeV

We report on the first measurements of J/ψ production at very low transverse momentum (p_{T}<0.2  GeV/c) in hadronic Au+Au collisions at sqrt[s_{NN}]=200  GeV and U+U collisions at sqrt[s_{NN}]=193  GeV. Remarkably, the inferred nuclear modification factor of J/ψ at midrapidity in Au+Au (U+U) collisions reaches about 24 (52) for p_{T}<0.05  GeV/c in the 60%-80% collision centrality class. This noteworthy enhancement cannot be explained by hadronic production accompanied by cold and hot medium effects. In addition, the dN/dt distribution of J/ψ for the very low p_{T} range is presented for the first time. The distribution is consistent with that expected from the Au nucleus and shows a hint of interference. Comparison of the measurements to theoretical calculations of coherent production shows that the excess yield can be described reasonably well and reveals a partial disruption of coherent production in semicentral collisions, perhaps due to the violent hadronic interactions. Incorporating theoretical calculations, the results strongly suggest that the dramatic enhancement of J/ψ yield observed at extremely low p_{T} originates from coherent photon-nucleus interactions. In particular, coherently produced J/ψ's in violent hadronic collisions may provide a novel probe of the quark-gluon plasma.