Emergence of Long-Range Angular Correlations in Low-Multiplicity Proton-Proton Collisions

This Letter presents the measurement of near-side associated per-trigger yields, denoted ridge yields, from the analysis of angular correlations of charged hadrons in proton-proton collisions at sqrt[s]=13  TeV. Long-range ridge yields are extracted for pairs of charged particles with a pseudorapidity difference of 1.4<|Δη|<1.8 and a transverse momentum of 1 Collapse

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First Measurement of the |t| Dependence of Incoherent J/ψ Photonuclear Production

The first measurement of the cross section for incoherent photonuclear production of J/ψ vector mesons as a function of the Mandelstam |t| variable is presented. The measurement was carried out with the ALICE detector at midrapidity, |y|<0.8, using ultraperipheral collisions of Pb nuclei at a center-of-mass energy per nucleon pair of sqrt[s_{NN}]=5.02  TeV. This rapidity interval corresponds to a Bjorken-x range (0.3-1.4)×10^{-3}. Cross sections are given in five |t| intervals in the range 0.04<|t|<1  GeV^{2} and compared to the predictions by different models. Models that ignore quantum fluctuations of the gluon density in the colliding hadron predict a |t| dependence of the cross section much steeper than in data. The inclusion of such fluctuations in the same models provides a better description of the data.

Anatomy beyond the pandemic: A Q-methodology study exploring student perceptions toward a hybrid curriculum

As a result of the COVID-19 pandemic, anatomy education was forced to adopt online modes of delivery. Previous research on student views revealed areas of strong preference (asynchronous lectures) and strong dislike (virtual specimens) in online anatomy courses. The current study seeks to compare the views of a single cohort of students experiencing both online and in-person undergraduate introductory anatomy and physiology courses. This comparison can highlight what students consider beneficial to their education and can inform future hybrid course offerings. Q-methodology was used to assess the opinions of students. Students sorted 41 statements on anatomy education in a quasi-normally distributed grid based on their degree of agreement with the statements. The rankings underwent a by-person factor analysis which categorized students with shared perceptions into groups. Data were collected from 246 students in the primarily online fall semester and 191 students in the primarily in-person winter semester. Analysis revealed three distinct factors (groups) in the cohort. Factor one (n = 113 (fall), n = 93 (winter)), was satisfied overall with the course materials and delivery. Factor two (n = 52 (fall), n = 18 (winter)) had a deep dislike of online learning, and factor three (n = 37 (fall), n = 49 (winter)) had a strong preference for online learning. While many students were comfortable in both online and in-person learning environments, this was not the case for all learners. The strengths and weaknesses of each teaching modality suggest the opportunity to explore hybrid learning as an option for future course offerings and specifically highlight valuable aspects to incorporate from each environment.

The experience of feeling old after a fragility fracture

BACKGROUND

There has been little exploration of the effect of fragility fractures on patient perceptions of their age. The common assumption is that fractures "happen to old people". In individuals with a fragility fracture, our objective was to explore the experience of feeling old after sustaining a fragility fracture.

METHODS

A secondary analysis of data from 145 community-dwelling women and men participating in six qualitative primary studies was conducted relying on a phenomenological approach. Participants were English-speaking, 45 years and older, who had sustained a recent fragility fracture or reported a history of previous fragility fractures. Data for the analysis included direct statements about feeling old as well any discussions relevant to age post-fracture.

RESULTS

We highlight two interpretations based on how individuals with a history of fragility fracture talked about age: (1) Participants described feeling old post-fracture. Several participants made explicit statements about being "old". However, the majority of participants discussed experiences post-fracture that implied that they felt old and had resigned themselves to being old. This appeared to entail a shift in thinking and perception of self that was permanent and had become a part of their identity; and (2) Perceptions of increasing age after sustaining a fracture were reinforced by health care providers, family, and friends.

CONCLUSIONS

Our findings challenge the notion that fractures "happen to old people" and suggest that fractures can make people feel old. Careful consideration of how bone health messages are communicated to patients post-fracture by health care providers is warranted. (Word Count: 248).

ψ(2S) Suppression in Pb-Pb Collisions at the LHC

The production of the ψ(2S) charmonium state was measured with ALICE in Pb-Pb collisions at sqrt[s_{NN}]=5.02  TeV, in the dimuon decay channel. A significant signal was observed for the first time at LHC energies down to zero transverse momentum, at forward rapidity (2.5 Collapse

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Effects of empagliflozin on progression of chronic kidney disease: a prespecified secondary analysis from the empa-kidney trial

BACKGROUND

Sodium-glucose co-transporter-2 (SGLT2) inhibitors reduce progression of chronic kidney disease and the risk of cardiovascular morbidity and mortality in a wide range of patients. However, their effects on kidney disease progression in some patients with chronic kidney disease are unclear because few clinical kidney outcomes occurred among such patients in the completed trials. In particular, some guidelines stratify their level of recommendation about who should be treated with SGLT2 inhibitors based on diabetes status and albuminuria. We aimed to assess the effects of empagliflozin on progression of chronic kidney disease both overall and among specific types of participants in the EMPA-KIDNEY trial.

METHODS

EMPA-KIDNEY, a randomised, controlled, phase 3 trial, was conducted at 241 centres in eight countries (Canada, China, Germany, Italy, Japan, Malaysia, the UK, and the USA), and included individuals aged 18 years or older with an estimated glomerular filtration rate (eGFR) of 20 to less than 45 mL/min per 1·73 m2, or with an eGFR of 45 to less than 90 mL/min per 1·73 m2 with a urinary albumin-to-creatinine ratio (uACR) of 200 mg/g or higher. We explored the effects of 10 mg oral empagliflozin once daily versus placebo on the annualised rate of change in estimated glomerular filtration rate (eGFR slope), a tertiary outcome. We studied the acute slope (from randomisation to 2 months) and chronic slope (from 2 months onwards) separately, using shared parameter models to estimate the latter. Analyses were done in all randomly assigned participants by intention to treat. EMPA-KIDNEY is registered at ClinicalTrials.gov, NCT03594110.

FINDINGS

Between May 15, 2019, and April 16, 2021, 6609 participants were randomly assigned and then followed up for a median of 2·0 years (IQR 1·5-2·4). Prespecified subgroups of eGFR included 2282 (34·5%) participants with an eGFR of less than 30 mL/min per 1·73 m2, 2928 (44·3%) with an eGFR of 30 to less than 45 mL/min per 1·73 m2, and 1399 (21·2%) with an eGFR 45 mL/min per 1·73 m2 or higher. Prespecified subgroups of uACR included 1328 (20·1%) with a uACR of less than 30 mg/g, 1864 (28·2%) with a uACR of 30 to 300 mg/g, and 3417 (51·7%) with a uACR of more than 300 mg/g. Overall, allocation to empagliflozin caused an acute 2·12 mL/min per 1·73 m2 (95% CI 1·83-2·41) reduction in eGFR, equivalent to a 6% (5-6) dip in the first 2 months. After this, it halved the chronic slope from -2·75 to -1·37 mL/min per 1·73 m2 per year (relative difference 50%, 95% CI 42-58). The absolute and relative benefits of empagliflozin on the magnitude of the chronic slope varied significantly depending on diabetes status and baseline levels of eGFR and uACR. In particular, the absolute difference in chronic slopes was lower in patients with lower baseline uACR, but because this group progressed more slowly than those with higher uACR, this translated to a larger relative difference in chronic slopes in this group (86% [36-136] reduction in the chronic slope among those with baseline uACR <30 mg/g compared with a 29% [19-38] reduction for those with baseline uACR ≥2000 mg/g; ptrend<0·0001).

INTERPRETATION

Empagliflozin slowed the rate of progression of chronic kidney disease among all types of participant in the EMPA-KIDNEY trial, including those with little albuminuria. Albuminuria alone should not be used to determine whether to treat with an SGLT2 inhibitor.

FUNDING

Boehringer Ingelheim and Eli Lilly.

Impact of primary kidney disease on the effects of empagliflozin in patients with chronic kidney disease: secondary analyses of the EMPA-KIDNEY trial

BACKGROUND

The EMPA-KIDNEY trial showed that empagliflozin reduced the risk of the primary composite outcome of kidney disease progression or cardiovascular death in patients with chronic kidney disease mainly through slowing progression. We aimed to assess how effects of empagliflozin might differ by primary kidney disease across its broad population.

METHODS

EMPA-KIDNEY, a randomised, controlled, phase 3 trial, was conducted at 241 centres in eight countries (Canada, China, Germany, Italy, Japan, Malaysia, the UK, and the USA). Patients were eligible if their estimated glomerular filtration rate (eGFR) was 20 to less than 45 mL/min per 1·73 m2, or 45 to less than 90 mL/min per 1·73 m2 with a urinary albumin-to-creatinine ratio (uACR) of 200 mg/g or higher at screening. They were randomly assigned (1:1) to 10 mg oral empagliflozin once daily or matching placebo. Effects on kidney disease progression (defined as a sustained ≥40% eGFR decline from randomisation, end-stage kidney disease, a sustained eGFR below 10 mL/min per 1·73 m2, or death from kidney failure) were assessed using prespecified Cox models, and eGFR slope analyses used shared parameter models. Subgroup comparisons were performed by including relevant interaction terms in models. EMPA-KIDNEY is registered with ClinicalTrials.gov, NCT03594110.

FINDINGS

Between May 15, 2019, and April 16, 2021, 6609 participants were randomly assigned and followed up for a median of 2·0 years (IQR 1·5-2·4). Prespecified subgroupings by primary kidney disease included 2057 (31·1%) participants with diabetic kidney disease, 1669 (25·3%) with glomerular disease, 1445 (21·9%) with hypertensive or renovascular disease, and 1438 (21·8%) with other or unknown causes. Kidney disease progression occurred in 384 (11·6%) of 3304 patients in the empagliflozin group and 504 (15·2%) of 3305 patients in the placebo group (hazard ratio 0·71 [95% CI 0·62-0·81]), with no evidence that the relative effect size varied significantly by primary kidney disease (pheterogeneity=0·62). The between-group difference in chronic eGFR slopes (ie, from 2 months to final follow-up) was 1·37 mL/min per 1·73 m2 per year (95% CI 1·16-1·59), representing a 50% (42-58) reduction in the rate of chronic eGFR decline. This relative effect of empagliflozin on chronic eGFR slope was similar in analyses by different primary kidney diseases, including in explorations by type of glomerular disease and diabetes (p values for heterogeneity all >0·1).

INTERPRETATION

In a broad range of patients with chronic kidney disease at risk of progression, including a wide range of non-diabetic causes of chronic kidney disease, empagliflozin reduced risk of kidney disease progression. Relative effect sizes were broadly similar irrespective of the cause of primary kidney disease, suggesting that SGLT2 inhibitors should be part of a standard of care to minimise risk of kidney failure in chronic kidney disease.

FUNDING

Boehringer Ingelheim, Eli Lilly, and UK Medical Research Council.

Measurements of Groomed-Jet Substructure of Charm Jets Tagged by D^{0} Mesons in Proton-Proton Collisions at sqrt[s]=13 TeV

Understanding the role of parton mass and Casimir color factors in the quantum chromodynamics parton shower represents an important step in characterizing the emission properties of heavy quarks. Recent experimental advances in jet substructure techniques have provided the opportunity to isolate and characterize gluon emissions from heavy quarks. In this Letter, the first direct experimental constraint on the charm-quark splitting function is presented, obtained via the measurement of the groomed shared momentum fraction of the first splitting in charm jets, tagged by a reconstructed D^{0} meson. The measurement is made in proton-proton collisions at sqrt[s]=13  TeV, in the low jet transverse-momentum interval of 15≤p_{T}^{jet ch}<30  GeV/c where the emission properties are sensitive to parton mass effects. In addition, the opening angle of the first perturbative emission of the charm quark, as well as the number of perturbative emissions it undergoes, is reported. Comparisons to measurements of an inclusive-jet sample show a steeper splitting function for charm quarks compared with gluons and light quarks. Charm quarks also undergo fewer perturbative emissions in the parton shower, with a reduced probability of large-angle emissions.

Adaptation of a Clinical Proton Pencil Beam Scanning System for FLASH Experiments

PURPOSE/OBJECTIVE(S)

To characterize a proton pencil beam scanning system for ultra-high dose rate (UHDR) irradiations and validate it with FLASH preclinical experiments.

MATERIALS/METHODS

After modifications to the beamline to maximize the beam current at isocenter in our gantry room, we characterized the UHDR beam in terms of: 1) Size and shape of the beam spot in three configurations; pristine beam, 75 mm water-equivalent-thickness (WET) range shifter (RS), and custom-built 135 mm WET RS mounted 310 mm upstream of the aperture in the snout housing. These configurations were analyzed to determine which one achieved the highest dose rate; 2) Beam transport efficiency and beam output. We compared the signal in the monitor chambers of the proton system with a Faraday cup and plane parallel ionization chamber (PPC05, IBA dosimetry) for beam current at the cyclotron from 7.5 nA to 800 nA; 3) Dose homogeneity, beam penumbra, and dose rate for the fields to be used in preclinical irradiations. All measurements were performed at isocenter, in air or at 1 cm depth in solid water, using the highest energy (about 230 MeV), which corresponded to a nominal range of 32.9 cm in water. We modeled the UHDR beam in our treatment planning system (TPS) to optimize the dose homogeneity and lateral penumbra of the irradiation fields. We performed the preclinical experiments in single fractions of 19 Gy (RBE), 21 Gy (RBE) and 23 Gy (RBE) (RBE = 1.1), targeting the pelvis of C57BL/6 mice and using survival as the endpoint. Each arm included 6-10 mice. The proton beam was used in transmission mode, positioning the center of the mouse pelvis at isocenter, and irradiating the pelvis with a 2x6 cm^2 field. Apertures were placed at 9cm from the isocenter to sharpen the lateral penumbra.

RESULTS

The range measurements with a multi-layer ionization chamber were consistent within 1 mm with the nominal range. In UHDR mode, the spot size at the isocenter varied from 4.5 mm for the pristine beam to 9.2 mm for the 135 mm RS. The spot size at isocenter remained constant when the beam intensity varied from 7.5 nA to 800 nA at the cyclotron exit. By employing the configuration with the 135 mm RS and optimizing the fields in the TPS, we achieved a dose rate of 1 Gy (RBE)/s for the conventional regime and 75(RBE) Gy/s for the UHDR regime. The monitor chambers of the proton system were affected by recombination at high dose rates: we observed about 35% higher output for the same number of monitor units delivered at 800 nA vs 7.5 nA. The delivered dose was determined with the PPC05 for each field, as this detector did not show recombination effects. When preclinical irradiations were independently monitored, the delivered dose was typically within 1% of the intended value. In three independent experiments, a dose of 21 Gy (RBE) or higher was associated with an increased survival in the UHDR arm compared to the conventional arm.

CONCLUSION

We adapted a clinical proton system for preclinical irradiations at UHDR. Our results confirm the presence of the FLASH effect.

Measurement of the Lifetime and Λ Separation Energy of _{Λ}^{3}H

The most precise measurements to date of the _{Λ}^{3}H lifetime τ and Λ separation energy B_{Λ} are obtained using the data sample of Pb-Pb collisions at sqrt[s_{NN}]=5.02  TeV collected by ALICE at the LHC. The _{Λ}^{3}H is reconstructed via its charged two-body mesonic decay channel (_{Λ}^{3}H→^{3}He+π^{-} and the charge-conjugate process). The measured values τ=[253±11(stat)±6(syst)]  ps and B_{Λ}=[102±63(stat)±67(syst)]  keV are compatible with predictions from effective field theories and confirm that the _{Λ}^{3}H structure is consistent with a weakly bound system.

Measurement of the J/ψ Polarization with Respect to the Event Plane in Pb-Pb Collisions at the LHC

We study the polarization of inclusive J/ψ produced in Pb-Pb collisions at sqrt[s_{NN}]=5.02  TeV at the LHC in the dimuon channel, via the measurement of the angular distribution of its decay products. We perform the study in the rapidity region 2.5 Collapse

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First Measurement of Antideuteron Number Fluctuations at Energies Available at the Large Hadron Collider

The first measurement of event-by-event antideuteron number fluctuations in high energy heavy-ion collisions is presented. The measurements are carried out at midrapidity (|η|<0.8) as a function of collision centrality in Pb-Pb collisions at sqrt[s_{NN}]=5.02  TeV using the ALICE detector. A significant negative correlation between the produced antiprotons and antideuterons is observed in all collision centralities. The results are compared with a state-of-the-art coalescence calculation. While it describes the ratio of higher order cumulants of the antideuteron multiplicity distribution, it fails to describe quantitatively the magnitude of the correlation between antiproton and antideuteron production. On the other hand, thermal-statistical model calculations describe all the measured observables within uncertainties only for correlation volumes that are different with respect to those describing proton yields and a similar measurement of net-proton number fluctuations.

Enhanced Deuteron Coalescence Probability in Jets

The transverse-momentum (p_{T}) spectra and coalescence parameters B_{2} of (anti)deuterons are measured in p-p collisions at sqrt[s]=13  TeV for the first time in and out of jets. In this measurement, the direction of the leading particle with the highest p_{T} in the event (p_{T}^{lead}>5  GeV/c) is used as an approximation for the jet axis. The event is consequently divided into three azimuthal regions, and the jet signal is obtained as the difference between the toward region, that contains jet fragmentation products in addition to the underlying event (UE), and the transverse region, which is dominated by the UE. The coalescence parameter in the jet is found to be approximately a factor of 10 larger than that in the underlying event. This experimental observation is consistent with the coalescence picture and can be attributed to the smaller average phase-space distance between nucleons in the jet cone as compared with the underlying event. The results presented in this Letter are compared to predictions from a simple nucleon coalescence model, where the phase-space distributions of nucleons are generated using pythia8 with the Monash 2013 tuning, and to predictions from a deuteron production model based on ordinary nuclear reactions with parametrized energy-dependent cross sections tuned on data. The latter model is implemented in pythia8.3. Both models reproduce the observed large difference between in-jet and out-of-jet coalescence parameters, although the almost flat trend of the B_{2}^{Jet} is not reproduced by the models, which instead give a decreasing trend.

A longitudinal Q-study to assess changes in students' perceptions at the time of pandemic

The COVID-19 pandemic forced many universities and colleges to rapidly adopt online course delivery. As with any new foray, realizing the optimal aspects of a course to change became incredibly important for course instructors. In this study, we used a particularly sensitive method, i.e. Q-methodology, to evaluate changes based on students' perceptions from fall 2020 to winter 2021. Q-methodology is commonly used to uncover shared values, opinions, and preferences. Using Q-methodology, students participating in both semesters of an undergraduate anatomy and physiology course were surveyed in fall 2020 and winter 2021. The Q-sample included 44 statements. Data from fall 2020 were treated as the baseline and changes in students' perceptions from 2020 to 2021 were assessed. In total, 31 students completed both fall 2020 and winter 2021 course evaluations. Three salient factors emerged from the fall 2020 evaluation: Overtaxed students, Solo Achievers, and In-Person Learners. At the baseline, students were concerned mostly about the delivery of the course, then the winter 2021 evaluation showed how they were adjusting to online learning. The longitudinal Q-study proved to be robust in identifying changes in perceptions. These granular findings indicate how students might differ in viewing and evaluating online courses. This methodology can be used in redesigning and restructuring different components of an online course in higher education settings.

Hypertriton Production in p-Pb Collisions at sqrt[s_{NN}]=5.02 TeV

The study of nuclei and antinuclei production has proven to be a powerful tool to investigate the formation mechanism of loosely bound states in high-energy hadronic collisions. The first measurement of the production of _{Λ}^{3}H in p-Pb collisions at sqrt[s_{NN}]=5.02  TeV is presented in this Letter. Its production yield measured in the rapidity interval -1<y<0 for the 40% highest-multiplicity p-Pb collisions is dN/dy=[6.3±1.8(stat)±1.2(syst)]×10^{-7}. The measurement is compared with the expectations of statistical hadronization and coalescence models, which describe the nucleosynthesis in hadronic collisions. These two models predict very different yields of the hypertriton in charged particle multiplicity environments relevant to small collision systems such as p-Pb, and therefore the measurement of dN/dy is crucial to distinguish between them. The precision of this measurement leads to the exclusion with a significance larger than 6.9σ of some configurations of the statistical hadronization model, thus constraining the theory behind the production of loosely bound states at hadron colliders.

Using Q‐Methodology to Evaluate Student Perceptions of Online Anatomy in the Time of COVID‐19

Background

Since the seventeenth century, the primary approach to teaching anatomy has involved hands‐on learning using cadaveric specimens. However, the ability to use this long‐standing tradition was curtailed in the 2020‐2021 school year due to the COVID‐19 pandemic. Many institutions closed physical classrooms entirely, launching experiential courses, such as anatomy, into the online space.

Hypothesis

We hypothesized that Q‐methodology could be used to uncover student perceptions of an introductory anatomy and physiology course that was offered online for the very first time.

Methods

Q‐methodology, considered the study of subjectivity, is an approach that statistically uncovers groups of individuals with shared perceptions within a larger cohort. Instructors can use Q‐methodology to identify groups of students with shared needs, allowing for more specific and productive course reform. In the current study, Q‐methodology was used as a means of course evaluation in the fall 2020 and winter 2021 semesters. Students were asked to sort 44 opinion‐based statements in a quasi‐normal table based on their level of agreement. By‐person factor analysis of 166 responses revealed three statistically distinct groups of students.

Results

The three groups were assigned the following monikers: Connected and Contented (CC), Disconnected and Disgruntled (DD), and Interconnected and Collaborative (IC). CC students (n=66) felt generally ambivalent toward course components and were comfortable with the technology skills required to participate in the online course space. DD students (n=50) were deeply unhappy with several elements of the course, including lectures, assignments, and evaluations. These students also felt as if they were teaching themselves. Finally, IC students (n=29) looked favourably upon the tutorial space and the role of teaching assistants. Analysis also revealed that some sentiments were shared across all three groups, including the preference for physical rather than virtual specimens, and the desire for more practice questions from faculty in order to prepare for bellringer exams. Interestingly, cohort opinions did not remain static across both semesters. There was a positive attitude shift as more students felt “Disconnected and Disgruntled” in the fall, and “Connected and Contented” in the winter.

Conclusions

These findings are useful for anatomy instructors interested in transitioning courses to an online or blended space, particularly in the face of ever evolving public health restrictions. The current study also models the wealth of information that can be uncovered using Q‐methodology ‐ useful for anyone interested in the previously amorphous study of subjectivity.

Patients experience a need for informal care after a fragility fracture

In this qualitative secondary analysis, patients with a fragility fracture described needing informal care post-fracture. A significant proportion reported receiving no care or not enough care, often devising strategies to care for themselves. Requesting help from multiple individuals allowed patients to minimize the burden to family and friends.

INTRODUCTION

In individuals with fragility fractures, our objectives were to examine (1) the experience of receiving informal care post-fracture; and (2) how these care experiences influenced post-fracture recovery and subsequent management of bone health.

METHODS

A secondary analysis of six primary qualitative studies was conducted. Individuals in the primary studies were English-speaking women and men, 45 years and older, who were living in the community and had sustained a recent fragility fracture or reported a history of previous fragility fractures. Participants who reported at least one instance of needing informal care were categorized as receiving "enough care", "insufficient care", or "no care".

RESULTS

Of 145 participants in the primary studies, 109 (75%) described needing informal care after their fracture. Of those needing care, 62 (57%) were categorized as receiving enough care while 47 (43%) were categorized as receiving insufficient or no care. The care needed affected the management of participants' fracture and bone health, including access to health care services. Participants who received insufficient or no care, especially those living alone, devised strategies to care for themselves and often requested help from multiple individuals to minimize the burden to family and friends. Compared with men, women appeared to report needing help with personal daily activities, such as bathing, and transportation to appointments related to bone health.

CONCLUSION

Informal care needs are an additional burden of fragility fractures. Post-fracture interventions should consider the broader context of patients' lives and potentially support the care needs of patients as part of their services.

Polarization of Λ and Λ[over ¯] Hyperons along the Beam Direction in Pb-Pb Collisions at sqrt[s]_{NN}=5.02 TeV

The polarization of the Λ and Λ[over ¯] hyperons along the beam (z) direction, P_{z}, has been measured in Pb-Pb collisions at sqrt[s_{NN}]=5.02  TeV recorded with ALICE at the Large Hadron Collider (LHC). The main contribution to P_{z} comes from elliptic flow-induced vorticity and can be characterized by the second Fourier sine coefficient P_{z,s2}=⟨P_{z}sin(2φ-2Ψ_{2})⟩, where φ is the hyperon azimuthal emission angle and Ψ_{2} is the elliptic flow plane angle. We report the measurement of P_{z,s2} for different collision centralities and in the 30%-50% centrality interval as a function of the hyperon transverse momentum and rapidity. The P_{z,s2} is positive similarly as measured by the STAR Collaboration in Au-Au collisions at sqrt[s_{NN}]=200  GeV, with somewhat smaller amplitude in the semicentral collisions. This is the first experimental evidence of a nonzero hyperon P_{z} in Pb-Pb collisions at the LHC. The comparison of the measured P_{z,s2} with the hydrodynamic model calculations shows sensitivity to the competing contributions from thermal and the recently found shear-induced vorticity, as well as to whether the polarization is acquired at the quark-gluon plasma or the hadronic phase.

COVID-19 vaccine associated demyelination & its association with MOG antibody

BACKGROUND

ChAdOx1-S (Covishield™/Vaxzervria, AstraZeneca) and BBV152 (Covaxin) SARS-CoV-2 vaccines are proven to be safe and effective, but rare complications have been reported.

OBJECTIVE

To describe reports of central nervous system (CNS) demyelination following ChAdOx1-S and BBV152 vaccinations.

METHODS & RESULTS

We report 29 (17 female; mean 38 years) cases of CNS demyelination; twenty-seven occurred in temporal association with ChAdOx1-S vaccine; two in association with BBV152 vaccine. Eleven patients had presentation with myelitis, six patients developed optic neuritis, five had acute demyelinating encephalomyelitis, three presented with brainstem demyelination, and four had multiaxial involvement. Myelin oligodendrocyte glycoprotein (MOG) antibodies were positive in ten patients. One patient with ADEM and tumefactive demyelinating lesions died after a prolonged intensive care unit stay and superimposed infection. As compared to the control group (87); the postvaccinial cases were found to have a significantly higher mean age, presence of encephalopathy (p value:0.0007), CSF pleocytosis (p value: 0.0094) and raised CSF protein (p value: 0.0062).

CONCLUSIONS

It is difficult to establish a causal relationship between vaccination and neurological adverse events such as demyelination. The temporal association with the vaccination and the presence of MOG antibodies raises the possibility of an immunogenic process triggered by the vaccine in susceptible individuals.

Measurement of the Groomed Jet Radius and Momentum Splitting Fraction in pp and Pb-Pb Collisions at sqrt[s_{NN}]=5.02 TeV

This article presents groomed jet substructure measurements in pp and Pb-Pb collisions at sqrt[s_{NN}]=5.02  TeV with the ALICE detector. The soft drop grooming algorithm provides access to the hard parton splittings inside a jet by removing soft wide-angle radiation. We report the groomed jet momentum splitting fraction, z_{g}, and the (scaled) groomed jet radius, θ_{g}. Charged-particle jets are reconstructed at midrapidity using the anti-k_{T} algorithm with resolution parameters R=0.2 and R=0.4. In heavy-ion collisions, the large underlying event poses a challenge for the reconstruction of groomed jet observables, since fluctuations in the background can cause groomed parton splittings to be misidentified. By using strong grooming conditions to reduce this background, we report these observables fully corrected for detector effects and background fluctuations for the first time. A narrowing of the θ_{g} distribution in Pb-Pb collisions compared to pp collisions is seen, which provides direct evidence of the modification of the angular structure of jets in the quark-gluon plasma. No significant modification of the z_{g} distribution in Pb-Pb collisions compared to pp collisions is observed. These results are compared with a variety of theoretical models of jet quenching, and provide constraints on jet energy-loss mechanisms and coherence effects in the quark-gluon plasma.

Measurement of Prompt D^{0}, Λ_{c}^{+}, and Σ_{c}^{0,++}(2455) Production in Proton-Proton Collisions at sqrt[s]=13 TeV

The p_{T}-differential production cross sections of prompt D^{0}, Λ_{c}^{+}, and Σ_{c}^{0,++}(2455) charmed hadrons are measured at midrapidity (|y|<0.5) in pp collisions at sqrt[s]=13  TeV. This is the first measurement of Σ_{c}^{0,++} production in hadronic collisions. Assuming the same production yield for the three Σ_{c}^{0,+,++} isospin states, the baryon-to-meson cross section ratios Σ_{c}^{0,+,++}/D^{0} and Λ_{c}^{+}/D^{0} are calculated in the transverse momentum (p_{T}) intervals 2<p_{T}<12 and 1<p_{T}<24  GeV/c. Values significantly larger than in e^{+}e^{-} collisions are observed, indicating for the first time that baryon enhancement in hadronic collisions also extends to the Σ_{c}. The feed-down contribution to Λ_{c}^{+} production from Σ_{c}^{0,+,++} is also reported and is found to be larger than in e^{+}e^{-} collisions. The data are compared with predictions from event generators and other phenomenological models, providing a sensitive test of the different charm-hadronization mechanisms implemented in the models.

Measurement of the Cross Sections of Ξ_{c}^{0} and Ξ_{c}^{+} Baryons and of the Branching-Fraction Ratio BR(Ξ_{c}^{0}→Ξ^{-}e^{+}ν_{e})/BR(Ξ_{c}^{0}→Ξ^{-}π^{+}) in pp Collisions at sqrt[s]=13 TeV

The p_{T}-differential cross sections of prompt charm-strange baryons Ξ_{c}^{0} and Ξ_{c}^{+} were measured at midrapidity (|y|<0.5) in proton-proton (pp) collisions at a center-of-mass energy sqrt[s]=13  TeV with the ALICE detector at the LHC. The Ξ_{c}^{0} baryon was reconstructed via both the semileptonic decay (Ξ^{-}e^{+}ν_{e}) and the hadronic decay (Ξ^{-}π^{+}) channels. The Ξ_{c}^{+} baryon was reconstructed via the hadronic decay (Ξ^{-}π^{+}π^{+}) channel. The branching-fraction ratio BR(Ξ_{c}^{0}→Ξ^{-}e^{+}ν_{e})/BR(Ξ_{c}^{0}→Ξ^{-}π^{+})=1.38±0.14(stat)±0.22(syst) was measured with a total uncertainty reduced by a factor of about 3 with respect to the current world average reported by the Particle Data Group. The transverse momentum (p_{T}) dependence of the Ξ_{c}^{0}- and Ξ_{c}^{+}-baryon production relative to the D^{0} meson and to the Σ_{c}^{0,+,++}- and Λ_{c}^{+}-baryon production are reported. The baryon-to-meson ratio increases toward low p_{T} up to a value of approximately 0.3. The measurements are compared with various models that take different hadronization mechanisms into consideration. The results provide stringent constraints to these theoretical calculations and additional evidence that different processes are involved in charm hadronization in electron-positron (e^{+}e^{-}) and hadronic collisions.

Λ_{c}^{+} Production and Baryon-to-Meson Ratios in pp and p-Pb Collisions at sqrt[s_{NN}]=5.02 TeV at the LHC

The prompt production of the charm baryon Λ_{c}^{+} and the Λ_{c}^{+}/D^{0} production ratios were measured at midrapidity with the ALICE detector in pp and p-Pb collisions at sqrt[s_{NN}]=5.02  TeV. These new measurements show a clear decrease of the Λ_{c}^{+}/D^{0} ratio with increasing transverse momentum (p_{T}) in both collision systems in the range 2<p_{T}<12  GeV/c, exhibiting similarities with the light-flavor baryon-to-meson ratios p/π and Λ/K_{S}^{0}. At low p_{T}, predictions that include additional color-reconnection mechanisms beyond the leading-color approximation, assume the existence of additional higher-mass charm-baryon states, or include hadronization via coalescence can describe the data, while predictions driven by charm-quark fragmentation processes measured in e^{+}e^{-} and e^{-}p collisions significantly underestimate the data. The results presented in this Letter provide significant evidence that the established assumption of universality (colliding-system independence) of parton-to-hadron fragmentation is not sufficient to describe charm-baryon production in hadronic collisions at LHC energies.

Experimental Evidence for an Attractive p-ϕ Interaction

This Letter presents the first experimental evidence of the attractive strong interaction between a proton and a ϕ meson. The result is obtained from two-particle correlations of combined p-ϕ⊕ p[over ¯]-ϕ pairs measured in high-multiplicity pp collisions at sqrt[s]=13  TeV by the ALICE Collaboration. The spin-averaged scattering length and effective range of the p-ϕ interaction are extracted from the fully corrected correlation function employing the Lednický-Lyuboshits approach. In particular, the imaginary part of the scattering length vanishes within uncertainties, indicating that inelastic processes do not play a prominent role for the p-ϕ interaction. These data demonstrate that the interaction is dominated by elastic p-ϕ scattering. Furthermore, an analysis employing phenomenological Gaussian- and Yukawa-type potentials is conducted. Under the assumption of the latter, the N-ϕ coupling constant is found to be g_{N-ϕ}=0.14±0.03(stat)±0.02(syst). This work provides valuable experimental input to accomplish a self-consistent description of the N-ϕ interaction, which is particularly relevant for the more fundamental studies on partial restoration of chiral symmetry in nuclear medium.

Multiharmonic Correlations of Different Flow Amplitudes in Pb-Pb Collisions at sqrt[s_{NN}]=2.76 TeV

The event-by-event correlations between three flow amplitudes are measured for the first time in Pb-Pb collisions, using higher-order symmetric cumulants. We find that different three-harmonic correlations develop during the collective evolution of the medium when compared to correlations that exist in the initial state. These new results cannot be interpreted in terms of previous lower-order flow measurements since contributions from two-harmonic correlations are explicitly removed in the new observables. A comparison to Monte Carlo simulations provides new and independent constraints for the initial conditions and system properties of nuclear matter created in heavy-ion collisions.

Soft-Dielectron Excess in Proton-Proton Collisions at sqrt[s]=13 TeV

A measurement of dielectron production in proton-proton (pp) collisions at sqrt[s]=13  TeV, recorded with the ALICE detector at the CERN LHC, is presented in this Letter. The data set was recorded with a reduced magnetic solenoid field. This enables the investigation of a kinematic domain at low dielectron (ee) invariant mass m_{ee} and pair transverse momentum p_{T,ee} that was previously inaccessible at the LHC. The cross section for dielectron production is studied as a function of m_{ee}, p_{T,ee}, and event multiplicity dN_{ch}/dη. The expected dielectron rate from hadron decays, called hadronic cocktail, utilizes a parametrization of the measured η/π^{0} ratio in pp and proton-nucleus collisions, assuming that this ratio shows no strong dependence on collision energy at low transverse momentum. Comparison of the measured dielectron yield to the hadronic cocktail at 0.15<m_{ee}<0.6  GeV/c^{2} and for p_{T,ee}<0.4  GeV/c indicates an enhancement of soft dielectrons, reminiscent of the "anomalous" soft-photon and soft-dilepton excess in hadron-hadron collisions reported by several experiments under different experimental conditions. The enhancement factor over the hadronic cocktail amounts to 1.61±0.13(stat)±0.17(syst,data)±0.34(syst,cocktail) in the ALICE acceptance. Acceptance-corrected excess spectra in m_{ee} and p_{T,ee} are extracted and compared with calculations of dielectron production from hadronic bremsstrahlung and thermal radiation within a hadronic many-body approach.

Elliptic Flow of Electrons from Beauty-Hadron Decays in Pb-Pb Collisions at sqrt[s_{NN}]=5.02 TeV

The elliptic flow of electrons from beauty hadron decays at midrapidity (|y|<0.8) is measured in Pb-Pb collisions at sqrt[s_{NN}]=5.02  TeV with the ALICE detector at the LHC. The azimuthal distribution of the particles produced in the collisions can be parametrized with a Fourier expansion, in which the second harmonic coefficient represents the elliptic flow, v_{2}. The v_{2} coefficient of electrons from beauty hadron decays is measured for the first time in the transverse momentum (p_{T}) range 1.3-6  GeV/c in the centrality class 30%-50%. The measurement of electrons from beauty-hadron decays exploits their larger mean proper decay length cτ≈500  μm compared to that of charm hadrons and most of the other background sources. The v_{2} of electrons from beauty hadron decays at midrapidity is found to be positive with a significance of 3.75  σ. The results provide insights into the degree of thermalization of beauty quarks in the medium. A model assuming full thermalization of beauty quarks is strongly disfavored by the measurement at high p_{T}, but is in agreement with the results at low p_{T}. Transport models including substantial interactions of beauty quarks with an expanding strongly interacting medium describe the measurement within uncertainties.

Evaluation of an Educational Outreach Campaign (IMPACT) on Pain Management Delivered to General Practices in Walsall

Introduction

Opioid class drugs are a commonly prescribed form of analgesic widely used in the treatment of acute, cancer and chronic non-cancer pain. Up to 90% of individuals presenting to pain centres receive opioids, with doctors in the UK prescribing more and stronger opioids (1). Concern is increasing that patients with chronic pain are inappropriately being moved up the WHO ‘analgesic ladder’, originally developed for cancer pain, without considering alternatives to medications, (2). UK guidelines on chronic non-cancer pain management recommend weak opioids as a second-line treatment, when the first-line non-steroidal anti-inflammatory drugs / paracetamol) ineffective, and for short-term use only. A UK educational outreach programme by the name IMPACT (Improving Medicines and Polypharmacy Appropriateness Clinical Tool) was conducted on pain management. This research evaluated the IMPACT campaign, analysing the educational impact on the prescribing of morphine, tramadol and other high-cost opioids, in the Walsall CCG.

Methods

Standardised training material was delivered to 50 practices between December 2018 and June 2019 by IMPACT pharmacists. The training included a presentation on pain control, including dissemination of local and national guidelines, management of neuropathic, low back pain and sciatica as well as advice for prescribers on prescribing opioids in long-term pain, with the evidence-base. Prescribing trends in primary care were also covered in the training, and clinicians were provided with resources to use in their practice. Data analysis included reviewing prescribing data and evaluating the educational intervention using feedback from participants gathered via anonymous questionnaires administered at the end of the training. Prescribing data analysis was conducted by Keele University’s Medicines Management team via the ePACT 2 system covering October 2018 to September 2019 (two months before and three months after the intervention) were presented onto graphs to form comparisons in prescribing trends of the Midland CCG compared to England.

Results

Questionnaires completed at the end of sessions showed high levels of satisfaction, with feedback indicating that participants found the session well presented, successful at highlighting key messages, and effective in using evidence-based practice. 88% of participants agreed the IMPACT campaign increased their understanding of the management and assessment of pain, and prescribing of opioids and other resources available to prescribers. The majority (85%) wished to see this form of education being repeated regularly in the future for other therapeutic areas. Analysis of the prescribing data demonstrated that the total volume of opioid analgesics decreased by 1.7% post-intervention in the Midlands CCG in response to the pharmacist-led educational intervention. As supported by literature, the use of educational strategies, including material dissemination and reminders as well as group educational outreach was effective in engaging clinicians, as demonstrated by the reduction in opioid prescribing and high GP satisfaction in this campaign.

Conclusion

The IMPACT campaign was effective at disseminating pain-specific guidelines for opioid prescribing to clinicians, leading to a decrease in overall prescribing of opioid analgesics. Educational outreach as an approach is practical and a valuable means to improve prescribing by continuing medical education.

References

1. Els, C., Jackson, T., Kunyk, D., Lappi, V., Sonnenberg, B., Hagtvedt, R., Sharma, S., Kolahdooz, F. and Straube, S. (2017). Adverse events associated with medium- and long-term use of opioids for chronic non-cancer pain: an overview of Cochrane Reviews. Cochrane Database of Systematic Reviews. This provided the statistic of percentage receiving opioids that present to pain centres.

2. Heit, H. (2010). Tackling the Difficult Problem of Prescription Opioid Misuse. Annals of Internal Medicine, 152(11), p.747. Issues with prescriptions and inappropriate moving up the WHO ladder.

Clinical characteristics, treatment and long-term prognosis in patients with anti-NMDAR encephalitis

OBJECTIVES

We aimed to (i) analyse the clinical characteristics, treatment outcome and long-term prognosis of anti-NMDAR encephalitis and (ii) study the differences between paediatric and adult patients.

METHODS

This was a chart review of all patients with anti-NMDAR encephalitis.

RESULTS

There were 28 patients with 18 patients belonging to the paediatric (<18 years) age group. There was female (94%) preponderance in the paediatric age group, while in adult patients, there was no gender predilection (p=0.006). There was no significant difference in clinical feature, outcome or number of relapses between paediatric and adult population groups. MRI brain was abnormal in 53% of patients. Among the 15 patients with MRI abnormalities at the onset, 53% had poor functional outcome at 1 year, while in 12 patients with normal initial MRI brain, only 8% had poor functional outcome at 1 year (p =0.01). Nearly 53% of patients with abnormal MRI at presentation had at least one clinical relapse within 2 years while in patients with normal MRI at presentation, 15% had a clinical relapse (p=0.037). EEG abnormalities were noticed in 71% of patients; among them, 40 and 15% had poor functional outcome at 1 and 2 years respectively. In comparison, those with normal first EEG at onset, 12% had poor functional outcome at 2 years (p=0.57).

CONCLUSIONS

Both paediatric and adult patients presented with similar clinical features but the paediatric population had female preponderance. The functional outcome and number of relapse were comparable in both the paediatric and adult groups. Patients with parenchymal changes on MRI and abnormal EEG showed poorer response compared to those with normal MRI and/or EEG at the onset. Patients have lesser severity of symptoms at relapse than in the first episode. An early diagnosis and treatment are essential for better long-term functional outcome.

Measurement of the Low-Energy Antideuteron Inelastic Cross Section

In this Letter, we report the first measurement of the inelastic cross section for antideuteron-nucleus interactions at low particle momenta, covering a range of 0.3≤p<4  GeV/c. The measurement is carried out using p-Pb collisions at a center-of-mass energy per nucleon-nucleon pair of sqrt[s_{NN}]=5.02  TeV, recorded with the ALICE detector at the CERN LHC and utilizing the detector material as an absorber for antideuterons and antiprotons. The extracted raw primary antiparticle-to-particle ratios are compared to the results from detailed ALICE simulations based on the geant4 toolkit for the propagation of (anti)particles through the detector material. The analysis of the raw primary (anti)proton spectra serves as a benchmark for this study, since their hadronic interaction cross sections are well constrained experimentally. The first measurement of the inelastic cross section for antideuteron-nucleus interactions averaged over the ALICE detector material with atomic mass numbers ⟨A⟩=17.4 and 31.8 is obtained. The measured inelastic cross section points to a possible excess with respect to the Glauber model parametrization used in geant4 in the lowest momentum interval of 0.3≤p<0.47  GeV/c up to a factor 2.1. This result is relevant for the understanding of antimatter propagation and the contributions to antinuclei production from cosmic ray interactions within the interstellar medium. In addition, the momentum range covered by this measurement is of particular importance to evaluate signal predictions for indirect dark-matter searches.

Having caregiving responsibilities affects management of fragility fractures and bone health

In this secondary analysis of six qualitative studies, we found that approximately one-quarter of individuals with fragility fracture were serving as informal caregivers. The caregiving role appeared to be a cause of the fracture for some and was prioritized over bone health, acting as a barrier to bone health management.

INTRODUCTION

Among fragility fracture patients serving as informal caregivers, our objective was to examine how caregiving responsibilities were associated with, and possibly impacted by, the fracture experience and the resulting management of bone health.

METHODS

We conducted a secondary analysis (amplified analysis) of six qualitative studies to understand caregiver responsibilities and the relationship between these responsibilities and patients' management of the fracture and bone health. The primary studies and the secondary analysis were conducted from a phenomenological approach. Eligible individuals in the primary studies were English-speaking men and women who were 45+ years old recruited from three settings (local, provincial, and national).

RESULTS

Without being prompted to talk about their experience of caregiving, 33 of 145 (23%) individuals reported they were providing care to a family member or friend at the time of their fracture or during recovery post-fracture. The experience of having caregiving responsibilities was related to the fracture and bone health in two ways: (1) the caregiving role appeared to be a cause of the fracture in some participants and (2) caregiving was prioritized over participants' own bone health and was a barrier to bone health management.

CONCLUSION

Fragility fracture is associated with, and potentially leads to an impairment of, an important social role in patients providing physical and emotional support and supervision for dependents as caregivers. Further, an important cause of fragility fracture can occur in the act of caregiving.

Probing the Effects of Strong Electromagnetic Fields with Charge-Dependent Directed Flow in Pb-Pb Collisions at the LHC

The first measurement at the LHC of charge-dependent directed flow (v_{1}) relative to the spectator plane is presented for Pb-Pb collisions at sqrt[s_{NN}]=5.02  TeV. Results are reported for charged hadrons and D^{0} mesons for the transverse momentum intervals p_{T}>0.2  GeV/c and 3<p_{T}<6  GeV/c in the 5%-40% and 10%-40% centrality classes, respectively. The difference between the positively and negatively charged hadron v_{1} has a positive slope as a function of pseudorapidity η, dΔv_{1}/dη=[1.68±0.49(stat)±0.41(syst)]×10^{-4}. The same measurement for D^{0} and D[over ¯]^{0} mesons yields a positive value dΔv_{1}/dη=[4.9±1.7(stat)±0.6(syst)]×10^{-1}, which is about 3 orders of magnitude larger than the one of the charged hadrons. These measurements can provide new insights into the effects of the strong electromagnetic field and the initial tilt of matter created in noncentral heavy ion collisions on the dynamics of light (u, d, and s) and heavy (c) quarks. The large difference between the observed Δv_{1} of charged hadrons and D^{0} mesons may reflect different sensitivity of the charm and light quarks to the early time dynamics of a heavy ion collision. These observations challenge some recent theoretical calculations, which predicted a negative and an order of magnitude smaller value of dΔv_{1}/dη for both light flavor and charmed hadrons.

Evidence of Spin-Orbital Angular Momentum Interactions in Relativistic Heavy-Ion Collisions

The first evidence of spin alignment of vector mesons (K^{*0} and ϕ) in heavy-ion collisions at the Large Hadron Collider (LHC) is reported. The spin density matrix element ρ_{00} is measured at midrapidity (|y|<0.5) in Pb-Pb collisions at a center-of-mass energy (sqrt[s_{NN}]) of 2.76 TeV with the ALICE detector. ρ_{00} values are found to be less than 1/3 (1/3 implies no spin alignment) at low transverse momentum (p_{T}<2  GeV/c) for K^{*0} and ϕ at a level of 3σ and 2σ, respectively. No significant spin alignment is observed for the K_{S}^{0} meson (spin=0) in Pb-Pb collisions and for the vector mesons in pp collisions. The measured spin alignment is unexpectedly large but qualitatively consistent with the expectation from models which attribute it to a polarization of quarks in the presence of angular momentum in heavy-ion collisions and a subsequent hadronization by the process of recombination.

In Vivo Evaluation of White Matter Abnormalities in Children with Duchenne Muscular Dystrophy Using DTI

BACKGROUND AND PURPOSE

Duchenne muscular dystrophy is an X-linked disorder characterized by progressive muscle weakness and prominent nonmotor manifestations, such as a low intelligence quotient and neuropsychiatric disturbance. We investigated WM integrity in patients with Duchenne muscular dystrophy using DTI.

MATERIALS AND METHODS

Fractional anisotropy and mean, axial, and radial diffusivity (DTI measures) were used to assess WM microstructural integrity along with neuropsychological evaluation in patients with Duchenne muscular dystrophy (n = 60) and controls (n = 40). Exon deletions in the DMD gene were confirmed using multiplex ligation-dependent probe amplification. Patients were classified into proximal (DMD Dp140+) and distal (DMD Dp140-) subgroups based on the location of the exon deletion and expression of short dystrophin Dp140 isoform. WM integrity was examined using whole-brain Tract-Based Spatial Statistics and atlas-based analysis of DTI data. The Pearson correlation was performed to investigate the possible relationship between neuropsychological scores and DTI metrics.

RESULTS

The mean ages of Duchenne muscular dystrophy and control participants were 8.0 ± 1.2 years and 8.2 ± 1.4 years, respectively. The mean age at disease onset was 4.1 ± 1.8 years, and mean illness duration was 40.8 ± 25.2 months. Significant differences in neuropsychological scores were observed between the proximal and distal gene-deletion subgroups, with more severe impairment in the distal-deletion subgroup (P < .05). Localized fractional anisotropy changes were seen in the corpus callosum, parietal WM, and fornices in the patient subgroup with Dp140+, while widespread changes were noted in the Dp140- subgroup. The Dp140+ subgroup showed increased axial diffusivity in multiple WM regions relative to the Dp140- subgroup. No significant correlation was observed between clinical and neuropsychological scores and diffusion metrics.

CONCLUSIONS

Widespread WM differences are evident in patients with Duchenne muscular dystrophy relative to healthy controls. Distal mutations in particular are associated with extensive WM abnormalities and poor neuropsychological profiles.

Intramedullary tumours and tumour mimics

Spinal cord lesions are traditionally classified as either extradural or intradural extramedullary or of intramedullary origin. Intramedullary spinal cord tumours are histopathologically similar to cranial tumours with a diverse range of pathologies. Astrocytomas and ependymomas account for approximately 80% of all intramedullary tumours, with other primary and secondary lesions accounting for the remaining 20%. Magnetic resonance imaging is the preferred imaging modality for diagnosing and characterising spinal cord lesions; however, accurate characterisation of tumour histology can be challenging, and is further confounded by intramedullary non-neoplastic lesions, such as demyelinating vascular, inflammatory, infectious, or traumatic lesions. This review illustrates the spectrum of intramedullary tumours and tumour mimics with emphasis on the imaging findings.

Scattering Studies with Low-Energy Kaon-Proton Femtoscopy in Proton-Proton Collisions at the LHC

The study of the strength and behavior of the antikaon-nucleon (K[over ¯]N) interaction constitutes one of the key focuses of the strangeness sector in low-energy quantum chromodynamics (QCD). In this Letter a unique high-precision measurement of the strong interaction between kaons and protons, close and above the kinematic threshold, is presented. The femtoscopic measurements of the correlation function at low pair-frame relative momentum of (K^{+}p⊕K^{-}p[over ¯]) and (K^{-}p⊕K^{+}p[over ¯]) pairs measured in pp collisions at sqrt[s]=5, 7, and 13 TeV are reported. A structure observed around a relative momentum of 58  MeV/c in the measured correlation function of (K^{-}p⊕K^{+}p[over ¯]) with a significance of 4.4σ constitutes the first experimental evidence for the opening of the (K[over ¯]^{0}n⊕K^{0}n[over ¯]) isospin breaking channel due to the mass difference between charged and neutral kaons. The measured correlation functions have been compared to Jülich and Kyoto models in addition to the Coulomb potential. The high-precision data at low relative momenta presented in this work prove femtoscopy to be a powerful complementary tool to scattering experiments and provide new constraints above the K[over ¯]N threshold for low-energy QCD chiral models.

Measurement of ϒ(1S) Elliptic Flow at Forward Rapidity in Pb-Pb Collisions at sqrt[s_{NN}]=5.02 TeV

The first measurement of the ϒ(1S) elliptic flow coefficient (v_{2}) is performed at forward rapidity (2.5<y<4) in Pb-Pb collisions at sqrt[s_{NN}]=5.02  TeV with the ALICE detector at the LHC. The results are obtained with the scalar product method and are reported as a function of transverse momentum (p_{T}) up to 15  GeV/c in the 5%-60% centrality interval. The measured ϒ(1S)v_{2} is consistent with 0 and with the small positive values predicted by transport models within uncertainties. The v_{2} coefficient in 2<p_{T}<15  GeV/c is lower than that of inclusive J/ψ mesons in the same p_{T} interval by 2.6 standard deviations. These results, combined with earlier suppression measurements, are in agreement with a scenario in which the ϒ(1S) production in Pb-Pb collisions at LHC energies is dominated by dissociation limited to the early stage of the collision, whereas in the J/ψ case there is substantial experimental evidence of an additional regeneration component.

Investigations of Anisotropic Flow Using Multiparticle Azimuthal Correlations in pp, p-Pb, Xe-Xe, and Pb-Pb Collisions at the LHC

Measurements of anisotropic flow coefficients (v_{n}) and their cross-correlations using two- and multiparticle cumulant methods are reported in collisions of pp at sqrt[s]=13  TeV, p-Pb at a center-of-mass energy per nucleon pair sqrt[s_{NN}]=5.02  TeV, Xe-Xe at sqrt[s_{NN}]=5.44  TeV, and Pb-Pb at sqrt[s_{NN}]=5.02  TeV recorded with the ALICE detector. The multiplicity dependence of v_{n} is studied in a very wide range from 20 to 3000 particles produced in the midrapidity region |η|<0.8 for the transverse momentum range 0.2<p_{T}<3.0  GeV/c. An ordering of the coefficients v_{2}>v_{3}>v_{4} is found in pp and p-Pb collisions, similar to that seen in large collision systems, while a weak v_{2} multiplicity dependence is observed relative to nucleus-nucleus collisions in the same multiplicity range. Using a novel subevent method, v_{2} measured with four-particle cumulants is found to be compatible with that from six-particle cumulants in pp and p-Pb collisions. The magnitude of the correlation between v_{n}^{2} and v_{m}^{2}, evaluated with the symmetric cumulants SC(m,n) is observed to be positive at all multiplicities for v_{2} and v_{4}, while for v_{2} and v_{3} it is negative and changes sign for multiplicities below 100, which may indicate a different v_{n} fluctuation pattern in this multiplicity range. The observed long-range multiparticle azimuthal correlations in high multiplicity pp and p-Pb collisions can neither be described by pythia 8 nor by impact-parameter-Glasma, music, and ultrarelativistic quantum molecular dynamics model calculations, and hence, provide new insights into the understanding of collective effects in small collision systems.