Dynamics of magnetization at infinite temperature in a Heisenberg spin chain

Understanding universal aspects of quantum dynamics is an unresolved problem in statistical mechanics. In particular, the spin dynamics of the one-dimensional Heisenberg model were conjectured as to belong to the Kardar-Parisi-Zhang (KPZ) universality class based on the scaling of the infinite-temperature spin-spin correlation function. In a chain of 46 superconducting qubits, we studied the probability distribution of the magnetization transferred across the chain's center, [Formula: see text]. The first two moments of [Formula: see text] show superdiffusive behavior, a hallmark of KPZ universality. However, the third and fourth moments ruled out the KPZ conjecture and allow for evaluating other theories. Our results highlight the importance of studying higher moments in determining dynamic universality classes and provide insights into universal behavior in quantum systems.

Stable quantum-correlated many-body states through engineered dissipation

Engineered dissipative reservoirs have the potential to steer many-body quantum systems toward correlated steady states useful for quantum simulation of high-temperature superconductivity or quantum magnetism. Using up to 49 superconducting qubits, we prepared low-energy states of the transverse-field Ising model through coupling to dissipative auxiliary qubits. In one dimension, we observed long-range quantum correlations and a ground-state fidelity of 0.86 for 18 qubits at the critical point. In two dimensions, we found mutual information that extends beyond nearest neighbors. Lastly, by coupling the system to auxiliaries emulating reservoirs with different chemical potentials, we explored transport in the quantum Heisenberg model. Our results establish engineered dissipation as a scalable alternative to unitary evolution for preparing entangled many-body states on noisy quantum processors.

Measurement-induced entanglement and teleportation on a noisy quantum processor

Measurement has a special role in quantum theory1: by collapsing the wavefunction, it can enable phenomena such as teleportation2 and thereby alter the 'arrow of time' that constrains unitary evolution. When integrated in many-body dynamics, measurements can lead to emergent patterns of quantum information in space-time3-10 that go beyond the established paradigms for characterizing phases, either in or out of equilibrium11-13. For present-day noisy intermediate-scale quantum (NISQ) processors14, the experimental realization of such physics can be problematic because of hardware limitations and the stochastic nature of quantum measurement. Here we address these experimental challenges and study measurement-induced quantum information phases on up to 70 superconducting qubits. By leveraging the interchangeability of space and time, we use a duality mapping9,15-17 to avoid mid-circuit measurement and access different manifestations of the underlying phases, from entanglement scaling3,4 to measurement-induced teleportation18. We obtain finite-sized signatures of a phase transition with a decoding protocol that correlates the experimental measurement with classical simulation data. The phases display remarkably different sensitivity to noise, and we use this disparity to turn an inherent hardware limitation into a useful diagnostic. Our work demonstrates an approach to realizing measurement-induced physics at scales that are at the limits of current NISQ processors.

Non-Abelian braiding of graph vertices in a superconducting processor

Indistinguishability of particles is a fundamental principle of quantum mechanics¹. For all elementary and quasiparticles observed to date-including fermions, bosons and Abelian anyons-this principle guarantees that the braiding of identical particles leaves the system unchanged^2,3. However, in two spatial dimensions, an intriguing possibility exists: braiding of non-Abelian anyons causes rotations in a space of topologically degenerate wavefunctions^4-8. Hence, it can change the observables of the system without violating the principle of indistinguishability. Despite the well-developed mathematical description of non-Abelian anyons and numerous theoretical proposals^9-22, the experimental observation of their exchange statistics has remained elusive for decades. Controllable many-body quantum states generated on quantum processors offer another path for exploring these fundamental phenomena. Whereas efforts on conventional solid-state platforms typically involve Hamiltonian dynamics of quasiparticles, superconducting quantum processors allow for directly manipulating the many-body wavefunction by means of unitary gates. Building on predictions that stabilizer codes can host projective non-Abelian Ising anyons^9,10, we implement a generalized stabilizer code and unitary protocol²³ to create and braid them. This allows us to experimentally verify the fusion rules of the anyons and braid them to realize their statistics. We then study the prospect of using the anyons for quantum computation and use braiding to create an entangled state of anyons encoding three logical qubits. Our work provides new insights about non-Abelian braiding and, through the future inclusion of error correction to achieve topological protection, could open a path towards fault-tolerant quantum computing.

Formation of robust bound states of interacting microwave photons

Systems of correlated particles appear in many fields of modern science and represent some of the most intractable computational problems in nature. The computational challenge in these systems arises when interactions become comparable to other energy scales, which makes the state of each particle depend on all other particles1. The lack of general solutions for the three-body problem and acceptable theory for strongly correlated electrons shows that our understanding of correlated systems fades when the particle number or the interaction strength increases. One of the hallmarks of interacting systems is the formation of multiparticle bound states2-9. Here we develop a high-fidelity parameterizable fSim gate and implement the periodic quantum circuit of the spin-½ XXZ model in a ring of 24 superconducting qubits. We study the propagation of these excitations and observe their bound nature for up to five photons. We devise a phase-sensitive method for constructing the few-body spectrum of the bound states and extract their pseudo-charge by introducing a synthetic flux. By introducing interactions between the ring and additional qubits, we observe an unexpected resilience of the bound states to integrability breaking. This finding goes against the idea that bound states in non-integrable systems are unstable when their energies overlap with the continuum spectrum. Our work provides experimental evidence for bound states of interacting photons and discovers their stability beyond the integrability limit.

Noise-resilient edge modes on a chain of superconducting qubits

Inherent symmetry of a quantum system may protect its otherwise fragile states. Leveraging such protection requires testing its robustness against uncontrolled environmental interactions. Using 47 superconducting qubits, we implement the one-dimensional kicked Ising model, which exhibits nonlocal Majorana edge modes (MEMs) with ℤ 2 parity symmetry. We find that any multiqubit Pauli operator overlapping with the MEMs exhibits a uniform late-time decay rate comparable to single-qubit relaxation rates, irrespective of its size or composition. This characteristic allows us to accurately reconstruct the exponentially localized spatial profiles of the MEMs. Furthermore, the MEMs are found to be resilient against certain symmetry-breaking noise owing to a prethermalization mechanism. Our work elucidates the complex interplay between noise and symmetry-protected edge modes in a solid-state environment.

The thalamus and its subregions – a gateway to obsessive-compulsive disorder

Introduction

Higher thalamic volume has been found in children with obsessive-compulsive disorder (OCD) and children with clinical-level symptoms within the general population (Boedhoe et al. 2017, Weeland et al. 2021a). Functionally distinct thalamic nuclei are an integral part of OCD-relevant brain circuitry.

Objectives

We aimed to study the thalamic nuclei volume in relation to subclinical and clinical OCD across different age ranges. Understanding the role of thalamic nuclei and their associated circuits in pediatric OCD could lead towards treatment strategies specifically targeting these circuits.

Methods

We studied the relationship between thalamic nuclei and obsessive-compulsive symptoms (OCS) in a large sample of school-aged children from the Generation R Study (N = 2500) (Weeland et al. 2021b). Using the data from the ENIGMA-OCD working group we conducted mega-analyses to study thalamic subregional volume in OCD across the lifespan in 2,649 OCD patients and 2,774 healthy controls across 29 sites (Weeland et al. 2021c). Thalamic nuclei were grouped into five subregions: anterior, ventral, intralaminar/medial, lateral and pulvinar (Figure 1).

Results

Both children with subclinical and clinical OCD compared with controls show increased volume across multiple thalamic subregions. Adult OCD patients have decreased volume across all subregions (Figure 2), which was mostly driven by medicated and adult-onset patients.

Conclusions

Our results suggests that OCD-related thalamic volume differences are global and not driven by particular subregions and that the direction of effects are driven by both age and medication status.

Disclosure

No significant relationships.

No Consistent Evidence for Brain Volumetric Correlates of Resilience in Two Independent Cohort Studies

Introduction

Childhood adversities have been associated with long-lasting brain morphological differences and poor psychological outcomes over the lifespan. Evidence with regard to protective factors counteracting the detrimental effect of childhood adversity on neurobiology is scarce.

Objectives

Therefore, we examined the interplay of childhood adversity with multiple protective factors in relation to brain morphology in a child and an adult cohort.

Methods

We analyzed data from two epidemiological longitudinal birth cohorts, the Generation R Study (N=3,008) and the Mannheim Study of Children at Risk (MARS) (N=179). Cumulative exposure to 12 adverse events (such as physical and sexual abuse), and the presence of protective factors, including child temperament, cognition, self-esteem, friendship quality and maternal sensitivity were assessed at different time points during childhood. Anatomical scans were acquired at the ages of 9-11 years in Generation R and at 25 years in MARS.

Results

Childhood adversity was related to smaller global brain volumes in Generation R, with similar effect sizes observed for the cerebellar volume in MARS. While small interaction effects between adversity and protective factors were found on the medial orbitofrontal cortex, the cerebellum and the amygdala in either cohort study, no interactions were consistent across cohorts or survived correction for multiple comparisons.

Conclusions

We found no consistent or strong evidence for interaction effects between multiple protective factors and childhood adversities on brain structure in a child and an adult cohort study. Instead, small interaction effects were found in either children or adults warranting further investigation and more fine-grained analyses.

Disclosure

TB:consultancy for Actelion, Hexal Pharma, Lilly, Lundbeck, Medice, Novartis, Shire; conference support by Lilly, Medice, Novartis, Shire; clinical trials by Shire and Viforpharma; royalties by Hogrefe, Kohlhammer, CIP Medien, Oxford University Press

Obsessive-compulsive symptoms and resting-state functional characteristics in pre-adolescent children from the general population

While functional brain characteristics of obsessive-compulsive disorder have been extensively studied, literature on network topology and subnetwork connectivity related to obsessive-compulsive symptoms (OCS) is sparse. Here we investigated the functional brain characteristics of OCS in children from the general population using a multiscale approach. Since we previously observed OCS-related differences in thalamus morphology, we also focused on the network participation of thalamic subregions. The study included 1701 participants (9-12 years) from the population-based Generation R study. OCS were measured using the Short Obsessive-Compulsive Disorder Screener. We studied the brain network at multiple scales: global network topology, subnetwork connectivity and network participation of thalamic nodes (pre-registration: https://osf.io/azr9c ). Modularity, small-worldness and average participation coefficient were calculated on the global scale. We used a data-driven consensus community approach to extract a partition of five subnetworks involving thalamic subregions and calculate the within- and between-subnetwork functional connectivity and topology. Multiple linear regression models were fitted to model the relationship between OCS and functional brain measures. No significant associations were found when using our preregistered definition of probable OCS. However, post-hoc analyses showed that children endorsing at least one OCS (compared with controls) had higher modularity, lower connectivity between frontoparietal, limbic and visual networks as well as altered participation of the lateral prefrontal thalamus node. Our results suggest that network characteristics of OCS in children from the general population are partly symptom-specific and severity-dependent. Thorough assessment of symptom dimensions can deepen our understanding of OCS-related brain networks.

Time-Crystalline Eigenstate Order on a Quantum Processor

Quantum many-body systems display rich phase structure in their low-temperature equilibrium states¹. However, much of nature is not in thermal equilibrium. Remarkably, it was recently predicted that out-of-equilibrium systems can exhibit novel dynamical phases^2–8 that may otherwise be forbidden by equilibrium thermodynamics, a paradigmatic example being the discrete time crystal (DTC)^7,9–15. Concretely, dynamical phases can be defined in periodically driven many-body-localized (MBL) systems via the concept of eigenstate order^7,16,17. In eigenstate-ordered MBL phases, the entire many-body spectrum exhibits quantum correlations and long-range order, with characteristic signatures in late-time dynamics from all initial states. It is, however, challenging to experimentally distinguish such stable phases from transient phenomena, or from regimes in which the dynamics of a few select states can mask typical behaviour. Here we implement tunable controlled-phase (CPHASE) gates on an array of superconducting qubits to experimentally observe an MBL-DTC and demonstrate its characteristic spatiotemporal response for generic initial states^7,9,10. Our work employs a time-reversal protocol to quantify the impact of external decoherence, and leverages quantum typicality to circumvent the exponential cost of densely sampling the eigenspectrum. Furthermore, we locate the phase transition out of the DTC with an experimental finite-size analysis. These results establish a scalable approach to studying non-equilibrium phases of matter on quantum processors.

A study establishes a scalable approach to engineer and characterize a many-body-localized discrete time crystal phase on a superconducting quantum processor.

Information scrambling in quantum circuits

[Figure: see text].

663 A Multi-centre National Study of the Effectiveness of Virtual Fracture Clinic Management of Orthopaedic Trauma during the COVID-19 Pandemic (MAVCOV): A Cross-sectional Study Protocol

Aim

Virtual fracture clinics (VFCs) are advocated by recent British Orthopaedic Association Standards for Trauma and Orthopaedics (BOASTs) to efficiently manage injuries during the COVID-19 pandemic. The primary aim of this national study is to assess the impact of these standards on patient satisfaction and clinical outcome amid the pandemic. The secondary aims are to determine the impact of the pandemic on demographics of injuries presenting to the VFC and to compare outcomes and satisfaction when the BOAST guidelines were first introduced with a subsequent period when local practice would be familiar with these guidelines.

Method

This is a national cross-sectional cohort study comprising centres with VFC services across the United Kingdom. All consecutive adult patients assessed at VFC pre-lockdown (6 May 2019 to 19 May 2019) and at the peak of the first lockdown (4 May 2020 to 17 May 2020), and a randomly selected sample during the second wave (October 2020) will be eligible for the study. Data comprising local VFC practice, patient and injury characteristics, unplanned re-attendances, and complications will be collected. A telephone questionnaire will be used to determine patient satisfaction and patient-reported outcomes for patients who were discharged following VFC assessment without face-to-face consultation.

Results

As of 31 October 2020, 51 hospitals with VFC services have been recruited to participate in this study.

Conclusions

The study results will identify changes in case-mix and numbers of patients managed through VFCs, due to urgent necessity, and whether this is safe and is associated with patient satisfaction to inform future clinical practice.

Fetal-placental blood flow and neurodevelopment in childhood: population-based neuroimaging study

OBJECTIVE

Antenatal Doppler measurements of the fetal umbilical and cerebral circulations can predict perinatal complications; however, it is unclear if subtle variations in antenatal Doppler measurements are associated with long-term neurodevelopmental outcome. In this study, we examined whether antenatal Doppler measurements of the fetal-placental circulation are associated with cognitive and motor abilities and brain morphology in childhood.

METHODS

To evaluate differences in long-term sequelae across the continuum of the umbilical and cerebral artery circulations in the general population, we utilized a population-based longitudinal cohort study approach. In women from the Generation R study, we measured second- and third-trimester umbilical artery pulsatility index (UA-PI). Children underwent non-verbal intelligence testing at 4-8 years of age, and at 8-12 years they underwent finger-tapping tests to measure fine motor skills, balance beam tests to measure gross motor skills and brain magnetic resonance imaging. We assessed the relationships between prenatal UA-PI and neurodevelopmental outcome using linear regression. We adjusted for child age and sex, maternal age, education, parity and smoking status.

RESULTS

The study sample included 2803 pregnancies. Higher third-trimester UA-PI was associated with poorer fine motor performance (0.41 (95% CI, 0.11-0.70) fewer taps on the finger-tapping test per 1 SD higher UA-PI) and gross motor performance (0.64 (95% CI, 0.20-1.08) fewer steps on the balance beam test per 1 SD higher UA-PI). One SD higher third-trimester UA-PI was also associated with 0.65 (95% CI, 0.04-1.25) points lower intelligence quotient; however, unlike the associations with motor abilities, this finding did not persist after correction for multiple testing. Higher second-trimester UA-PI was associated with smaller brain volume (6.1 (95% CI, 1.0-11.3) cm³ reduction per 1 SD higher UA-PI), but the association did not persist after correction for multiple testing.

CONCLUSION

Higher placental vascular resistance may have mild adverse effects on neurodevelopmental outcome at school age. While these effects are subtle at population level, we encourage future research into the role of early circulation in brain development. This information could be used to develop targeted interventions. © 2020 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology.

989 Improving the Completion of Hospital Anticipatory Care Plans in Orthopaedic Trauma Wards During The COVID-19 Pandemic

Background

The COVID-19 pandemic has highlighted the importance of the Hospital Anticipatory Care Plan (HACP). New guidance recommends all patients admitted acutely to hospital should have a HACP completed within 24 hours. We aimed to assess how many orthopaedic trauma patients admitted to the study centre had HACP completed within 24 hours of admission.

Method

Departmental Quality Improvement Project (QIP) permission was granted, and standard audit protocol was utilised. Data were collected in a retrospective manner using our trauma database and online patient record system. Educational interventions including staff teaching sessions and dissemination of infographic posters were implemented. Cycle two was repeated in similar fashion.

Results

Cycle one (50 patients): 37/50(74%) had HACPs completed. Of those with HACPs, 18/37(49%) were completed within 24 hours. Median time to completion was 45.3 hours (range 0.4-275.1 hours). Cycle two (58 patients): HACP completion significantly improved (56/58, 97%; p < 0.01), with more completed within 24 hours (50/56, 89%; p < 0.01). The median time to completion was decreased to 4.92 hours (range 0.27-60.6; p < 0.01).

Conclusions

Unit compliance was initially poor however significantly improved with educational measures. Failing to identify ceilings of care early can result in difficult decisions having to be made in critical situations, risking suboptimal patient care.

Testing sampling bias in estimates of adolescent social competence and behavioral control

In 5 of the 6 large Dutch developmental cohorts investigated here, lower SES adolescents are underrepresented and higher SES adolescents overrepresented. With former studies clearly revealing differences between SES strata in adolescent social competence and behavioral control, this misrepresentation may contribute to an overestimation of normative adolescent competence. Using a raking procedure, we used national census statistics to weigh the cohorts to be more representative of the Dutch population. Contrary to our expectations, in all cohorts, little to no differences between SES strata were found in the two outcomes. Accordingly, no differences between weighted and unweighted mean scores were observed across all cohorts. Furthermore, no clear change in correlations between social competence and behavioral control was found. These findings are most probably explained by the fact that measures of SES in the samples were quite limited, and the low SES participants in the cohorts could not be considered as representative of the low SES groups in the general population. Developmental outcomes associated with SES may be affected by a raking procedure in other cohorts that have a sufficient number and sufficient variation of low SES adolescents.

Hartree-Fock on a superconducting qubit quantum computer

The simulation of fermionic systems is among the most anticipated applications of quantum computing. We performed several quantum simulations of chemistry with up to one dozen qubits, including modeling the isomerization mechanism of diazene. We also demonstrated error-mitigation strategies based on N-representability that dramatically improve the effective fidelity of our experiments. Our parameterized ansatz circuits realized the Givens rotation approach to noninteracting fermion evolution, which we variationally optimized to prepare the Hartree-Fock wave function. This ubiquitous algorithmic primitive is classically tractable to simulate yet still generates highly entangled states over the computational basis, which allowed us to assess the performance of our hardware and establish a foundation for scaling up correlated quantum chemistry simulations.

Structural brain differences in pre-adolescents who persist in and recover from stuttering

•

Brain (micro-)structural differences were found in pre-adolescents who stutter.

•

Persistency was associated with marginally smaller left frontal gray matter volume.

•

Recovery was associated with higher mean diffusivity in white matter tracts.

•

Distinct brain structures implicated in persistence and recovery of stuttering.

Background

Stuttering is a complex speech fluency disorder occurring in childhood. In young children, stuttering has been associated with speech-related auditory and motor areas of the brain. During transition into adolescence, the majority of children who stutter (75–80%) will experience remission of their symptoms. The current study evaluated brain (micro-)structural differences between pre-adolescents who persisted in stuttering, those who recovered, and fluently speaking controls.

Methods

This study was embedded in the Generation R Study, a population-based cohort in the Netherlands of children followed from pregnancy onwards. Neuroimaging was performed in 2211 children (mean age: 10 years, range 8–12), of whom 20 persisted in and 77 recovered from stuttering. Brain structure (e.g., gray matter) and microstructure (e.g., diffusion tensor imaging) differences between groups were tested using multiple linear regression.

Results

Pre-adolescents who persisted in stuttering had marginally lower left superior frontal gray matter volume compared to those with no history of stuttering (β −1344, 95%CI −2407;-280), and those who recovered (β −1825, 95%CI −2999;-650). Pre-adolescents who recovered, compared to those with no history of stuttering, had higher mean diffusivity in the forceps major (β 0.002, 95%CI 0.001;0.004), bilateral superior longitudinal fasciculi (β 0.001, 95%CI 0.000;0.001), left corticospinal tract (β 0.003, 95%CI 0.002;0.004), and right inferior longitudinal fasciculus (β 0.001, 95%CI 0.000;0.001).

Conclusion

Findings suggest that relatively small difference in prefrontal gray matter volume is associated with persistent stuttering, and alterations in white matter tracts are apparent in individuals who recovered. The findings further strengthen the potential relevance of brain (micro-)structure in persistence and recovery from stuttering in pre-adolescents.

Comparative Neuropsychiatry: White Matter Abnormalities in Children and Adolescents with Schizophrenia, Bipolar Affective Disorder, and Obsessive-Compulsive Disorder

Background:

There is considerable evidence that white matter abnormalities play a key role in the pathogenesis of a number of major psychiatric disorders, including schizophrenia, bipolar affective disorder, and obsessive-compulsive disorder. Few studies, however, have compared white matter abnormalities early in the course of the illness.

Methods:

A total of 102 children and adolescents participated in the study, including 43 with early-onset schizophrenia, 13 with early-onset bipolar affective disorder, 17 with obsessive-compulsive disorder, and 29 healthy controls. Diffusion tensor imaging scans were obtained on all children and the images were assessed for the presence of non-spatially overlapping regions of white matter differences, a novel algorithm known as the pothole approach.

Results:

Patients with early-onset schizophrenia and early-onset bipolar affective disorder had a significantly greater number of white matter potholes compared to controls, but the total number of potholes did not differ between the two groups. The volumes of the potholes were significantly larger in patients with early-onset bipolar affective disorder compared to the early-onset schizophrenia group. Children and adolescents with obsessive-compulsive disorder showed no differences in the total number of white matter potholes compared to controls.

Conclusions:

White matter abnormalities in early-onset schizophrenia and bipolar affective disorder are more global in nature, whereas children and adolescents with obsessive-compulsive disorder do not show widespread differences in FA.

Sustaining global partnerships for simulation integration: lessons from the field

AIM

A reciprocal partnership between two World Health Organization Collaborating Centers in the Americas region aimed to strengthen nursing and midwifery education through innovative integration of high-fidelity simulation.

METHODS/IMPLEMENTATION

Immersion of a visiting scholar in six-week training within a North American nursing school (host) solidified simulation champion designation, upon return at the home institution. Next, two expert nursing faculty implemented a train-the-trainer simulation course on-site. Following evaluation and virtual debriefing, a midwifery faculty visited the host institution for second-round training.

CONCLUSION

This ongoing program targets faculty development needs through a strong academic partnership, built upon global awareness and sustainable engagement.

Diabatic Gates for Frequency-Tunable Superconducting Qubits

We demonstrate diabatic two-qubit gates with Pauli error rates down to 4.3(2)×10^{-3} in as fast as 18 ns using frequency-tunable superconducting qubits. This is achieved by synchronizing the entangling parameters with minima in the leakage channel. The synchronization shows a landscape in gate parameter space that agrees with model predictions and facilitates robust tune-up. We test both iswap-like and cphase gates with cross-entropy benchmarking. The presented approach can be extended to multibody operations as well.

Reduced egg shedding in nematode-resistant ewes and projected epidemiological benefits under climate change

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Exlana breed ewes were monitored for gastrointestinal nematodes during the peri-parturient period.

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Ewes selected for resistance when lambs produced fewer eggs as adults.

•

There was no observed reproductive cost to resistance.

•

Simulations predict that lambs of resistant ewes are exposed to reduced infection pressure.

•

Nematode resistance in the female line could help mitigate the impact of climate change on infection pressure.

Global livestock production is facing serious new challenges, including climate-driven changes in parasite epidemiology, and anthelmintic resistance, driving a need for non-chemotherapeutic methods of parasite control. Selecting for genetic resistance to gastrointestinal nematode infection could reduce reliance on chemical intervention and mitigate increases in parasite challenge due to climate change. Ewes of the composite Exlana breed with a range of estimated breeding values (EBVs) based on nematode faecal egg counts (FECs) were monitored during the peri-parturient period on two farms in southwestern England. Ewes with low EBVs (“resistant”) had lower FECs during the peri-parturient period than those with high EBVs (“susceptible”): the mean FEC was reduced by 23% and 34% on Farms 1 and 2, respectively, while the peak FEC was reduced by 30% and 37%, respectively. Neither EBV nor FEC were correlated with key performance indicators (estimated milk yield, measured indirectly using 8 week lamb weight, and ewe weight loss during lactation). Simulations predict that the reduced FECs of resistant ewes would result in a comparable reduction in infection pressure (arising from eggs shed by ewes) for their lambs. Furthermore, although the reduced FECs observed were modest, simulations predicted that selecting for nematode resistance in ewes could largely offset predicted future climate-driven increases in pasture infectivity arising from eggs contributed by these ewes. Selective breeding of the maternal line for nematode resistance therefore has potential epidemiological benefits by reducing pasture infectivity early in the grazing season and alleviating the need for anthelmintic treatment of ewes during the peri-parturient period, thus reducing selection pressure for anthelmintic resistance. These benefits are magnified under predicted future climate change. The maternal line warrants more attention in selective breeding programmes for nematode resistance.

A-32 Interpreting Change on the Neuropsychological Assessment Battery

Objective

The Neuropsychological Assessment Battery (NAB) is a comprehensive, modular battery of neuropsychological tests assessing of a wide array of cognitive skills and functions in adults. The purpose of the current study is to provide additional statistical evidence to support interpretation of NAB score changes over time.

Method

Participants were healthy community-dwelling adults, ages 18 to 97 years, from the NAB standardization sample that was assessed on the NAB a second time (n = 95). Reliable change index scores were calculated for the five domain indexes and the total index at several levels of significance. Base rates of score differences between Time 1 and Time 2 were examined.

Results

Across the indexes, significant score differences (at p < .05) ranged from 17 to 28 standard score points for adults (ages 18 to 59 years) and from 13 to 23 standard score points for older adults (ages 60 to 97 years). Approximately 67-89% of adult participants had Time 1 and Time 2 scores within 1 standard deviation (SD) of each other, while older adults ranged from 73-97%. Only 0-4% of adults and older adults had a large decline on any score (greater than 2 SDs). 1-2% of adults and 3-5% of older adults had a large improvement on any score (greater than 2 SDs).

Conclusions

These data allow clinicians to determine the statistical significance of NAB score differences, as well as quantify the frequency of the observed differences.

Stuttering and gray matter morphometry: A population-based neuroimaging study in young children

Stuttering is a developmental speech disorder originating in early childhood. We aimed to replicate the association of stuttering and structural morphometry using a large, population-based prospective cohort, the Generation R Study, and explore the neurobiological mechanism of stuttering in children. Twenty-six children with a history of stuttering and 489 fluent speaking peers (ages 6-9) were included in the MRI sub-study. Cortical and subcortical regions of interest were analyzed using linear regression models. Compared to fluent speakers, children with a history of stuttering had less gray matter volume in the left inferior frontal gyrus and supplementary motor area. Exploratory surface-based brain analysis showed thinner cortex in the left inferior frontal gyrus, and in bilateral frontal and parietal areas. These findings corroborate previous studies that reported aberrant brain morphometry in speech motor and auditory regions in children who stutter. Future research is needed to explore the causal nature of this association.

Cavum Septum Pellucidum in the General Pediatric Population and Its Relation to Surrounding Brain Structure Volumes, Cognitive Function, and Emotional or Behavioral Problems

BACKGROUND AND PURPOSE

The cavum septum pellucidum, a cavity filled with CSF, is localized between the 2 lateral ventricles of the brain. The cavum is present in all neonates, but it typically closes within 5 months after birth. In some cases, this closure does not occur and a persistent or enlarged cavum septum pellucidum has been linked, in some studies, to psychiatric disorders. However, the clinical relevance in the general population is unknown. In this study, we examined the relationship between the cavum septum pellucidum and volumes of brain structures, cognitive function, and emotional and behavioral problems in children.

MATERIALS AND METHODS

This study was embedded in the Generation R Study, a prospective cohort in Rotterdam, the Netherlands. MR imaging studies of 1070 children, 6-10 years of age, were systematically evaluated for the presence and length of a persistent cavum septum pellucidum. An enlarged cavum septum pellucidum was defined as a cavum length of ≥6 mm. Groups without, with persistent, and with enlarged cavum septi pellucidi were compared for brain structure volumes, nonverbal intelligence, and emotional and behavioral problems.

RESULTS

The prevalence of cavum septi pellucidi in our sample was 4.6%. Children with an enlarged cavum septum pellucidum had a larger corpus callosum, greater thalamic and total white matter-to-total brain volume ratio, and smaller lateral ventricle volumes. We did not find a relationship between cavum septi pellucidi and cognitive function or emotional and behavioral problems.

CONCLUSIONS

The cavum septum pellucidum is a normal structural brain variation without clinical implications in this population-based sample of school-aged children.

Widespread white matter microstructural differences in schizophrenia across 4322 individuals: results from the ENIGMA Schizophrenia DTI Working Group

The regional distribution of white matter (WM) abnormalities in schizophrenia remains poorly understood, and reported disease effects on the brain vary widely between studies. In an effort to identify commonalities across studies, we perform what we believe is the first ever large-scale coordinated study of WM microstructural differences in schizophrenia. Our analysis consisted of 2359 healthy controls and 1963 schizophrenia patients from 29 independent international studies; we harmonized the processing and statistical analyses of diffusion tensor imaging (DTI) data across sites and meta-analyzed effects across studies. Significant reductions in fractional anisotropy (FA) in schizophrenia patients were widespread, and detected in 20 of 25 regions of interest within a WM skeleton representing all major WM fasciculi. Effect sizes varied by region, peaking at (d=0.42) for the entire WM skeleton, driven more by peripheral areas as opposed to the core WM where regions of interest were defined. The anterior corona radiata (d=0.40) and corpus callosum (d=0.39), specifically its body (d=0.39) and genu (d=0.37), showed greatest effects. Significant decreases, to lesser degrees, were observed in almost all regions analyzed. Larger effect sizes were observed for FA than diffusivity measures; significantly higher mean and radial diffusivity was observed for schizophrenia patients compared with controls. No significant effects of age at onset of schizophrenia or medication dosage were detected. As the largest coordinated analysis of WM differences in a psychiatric disorder to date, the present study provides a robust profile of widespread WM abnormalities in schizophrenia patients worldwide. Interactive three-dimensional visualization of the results is available at www.enigma-viewer.org.

Spectroscopic signatures of localization with interacting photons in superconducting qubits

Quantized eigenenergies and their associated wave functions provide extensive information for predicting the physics of quantum many-body systems. Using a chain of nine superconducting qubits, we implement a technique for resolving the energy levels of interacting photons. We benchmark this method by capturing the main features of the intricate energy spectrum predicted for two-dimensional electrons in a magnetic field-the Hofstadter butterfly. We introduce disorder to study the statistics of the energy levels of the system as it undergoes the transition from a thermalized to a localized phase. Our work introduces a many-body spectroscopy technique to study quantum phases of matter.

Severity strata for five patient-reported outcomes in adults with atopic dermatitis

BACKGROUND

Several patient-reported outcomes have been used to assess the burden of atopic dermatitis (AD). Some are disease specific, such as the Patient-Oriented Eczema Measure (POEM), while others pertain to itch, for example the numerical rating scale (NRS)-itch, ItchyQoL and 5-D itch, or dermatological disease in general, for example the Dermatology Life Quality Index (DLQI). Development of severity strata is essential for proper interpretability of these assessments.

OBJECTIVES

To confirm previously developed strata for POEM, DLQI and raw ItchyQoL, and develop strata for the NRS-itch, mean ItchyQoL and 5-D itch scale for use in adults with AD.

METHODS

Self-administered questionnaires were completed by 210 adults with AD in a dermatology practice setting. Strata were selected using an anchoring approach based on patient-reported disease severity.

RESULTS

We confirmed the existing strata for POEM (mild 0-7, moderate 8-16, severe 17-28; κ = 0·440), DLQI (mild 0-5, moderate 6-10, severe 11-30; κ = 0·398) and NRS-itch (mild 0-3, moderate 4-6, severe 7-10; κ = 0·499). However, the preferred band for raw ItchyQoL was mild 22-58, moderate 59-74 and severe 75-110 (κ = 0·379) and for mean ItchyQoL, mild 1-2·9, moderate 3·0-3·9, severe 4·0-5·0 (κ = 0·374). The preferred band for 5-D itch scale was mild 0-11, moderate 12-17 and severe 18-25 (κ = 0·331).

CONCLUSIONS

Existing strata for POEM and DLQI performed well in adult AD. Previously reported strata for visual analogue scale-itch performed best for NRS-itch. We identified banding for the raw ItchyQoL for our AD population that varies slightly from the banding published for a more heterogeneous population. Finally, we proposed strata for mean ItchyQoL and 5-D itch scale in adult AD.

Validation of patient-reported global severity of atopic dermatitis in adults

BACKGROUND

Atopic dermatitis (AD) is associated with a heterogeneous presentation and clinical course. There is a lack of simple and validated severity assessments that are feasible for clinical practice and epidemiological research.

OBJECTIVES

We sought to validate patient-reported global AD severity in adults.

METHODS

We performed a prospective dermatology practice-based study using questionnaires and evaluation by a dermatologist (n = 265).

RESULTS

At baseline and follow-up, patient-reported global AD severity significantly correlated with oSCORAD (Spearman ρ = 0.56 and 0.49), SCORAD (0.64 and 0.56), EASI (0.56 and 0.50), BSA (0.52 and 0.45), NRS-itch (0.60 and 0.53), POEM (0.50 and 0.48), and DLQI (0.50 and 0.49) (P < .0001 for all). Patient-reported moderate and severe AD vs mild AD were associated with significantly higher oSCORAD, SCORAD, EASI, BSA, NRS-itch, POEM, and DLQI (P < .0001 for all). There was moderate concordance between patient-reported AD severity (mild, moderate, and severe) and previously developed severity strata for oSCORAD (κ = 0.39), SCORAD (κ = 0.47), EASI (κ = 0.37), NRS-itch (κ = 0.49), POEM (κ = 0.37), and DLQI (κ = 0.40). Among patients with severe disease at baseline, those who reported mild or moderate disease on follow-up had significantly greater absolute reductions of oSCORAD (-23.4/-9.7/-1.8), SCORAD (-33.0/-13.2/-2.3), EASI (-17.1/-9.8/-3.2), BSA (-46%/-15%/-4%), NRS-itch (-5/-2/0), POEM (-5/-2/0), and DLQI (-8/-6/-1) than those who continued to report severe disease (Kruskal-Wallis, P ≤ .0003 for all).

CONCLUSIONS

Patient-reported AD severity appears to be sufficiently valid for assessing AD severity in the clinical and epidemiological setting.

Adiposity and grip strength as long-term predictors of objectively measured physical activity in 93 015 adults: the UK Biobank study

Background/Objectives:

Fatness and fitness are associated with physical activity (PA) but less is known about the prospective associations of adiposity and muscle strength with PA. This study aimed to determine longitudinal associations of body mass index (BMI), waist circumference (WC) and grip strength (GS) with objectively measured PA.

Subjects/Methods:

Data are from the UK Biobank study. At baseline (2006–2010), BMI, WC and GS were objectively measured. At follow-up (2013–2015), a sub-sample of 93 015 participants (52 161 women) wore a tri-axial accelerometer on the dominant wrist for 7 days. Linear regression was performed to investigate longitudinal associations of standardised BMI, WC and GS at baseline with moderate-to-vigorous PA (MVPA) and acceleration after a median 5.7-years follow-up (interquartile range: 4.9–6.5 years).

Results:

Linear regression revealed strong inverse associations for BMI and WC, and positive associations for GS with follow-up PA; in women, MVPA ranges from lowest to highest quintiles of GS were 42–48 min day⁻¹ in severely obese (BMI⩾35 kg m⁻²), 52–57 min day⁻¹ in obese (30⩽BMI<35 kg m⁻²), 61–65 min day⁻¹ in overweight (25⩽BMI<30 kg m⁻²) and 69–75 min day⁻¹ in normal weight (18.5⩽BMI<25 kg m⁻²). Follow-up MVPA was also lower in the lowest GS quintile (42–69 min day⁻¹) compared with the highest GS quintile (48–75 min day⁻¹) across BMI categories in women. The pattern of these associations was generally consistent for men, and in analyses using WC and mean acceleration as exposure and outcome, respectively.

Conclusions:

More pronounced obesity and poor strength at baseline independently predict lower activity levels at follow-up. Interventions and policies should aim to improve body composition and muscle strength to promote active living.

Measurement-Induced State Transitions in a Superconducting Qubit: Beyond the Rotating Wave Approximation

Many superconducting qubit systems use the dispersive interaction between the qubit and a coupled harmonic resonator to perform quantum state measurement. Previous works have found that such measurements can induce state transitions in the qubit if the number of photons in the resonator is too high. We investigate these transitions and find that they can push the qubit out of the two-level subspace, and that they show resonant behavior as a function of photon number. We develop a theory for these observations based on level crossings within the Jaynes-Cummings ladder, with transitions mediated by terms in the Hamiltonian that are typically ignored by the rotating wave approximation. We find that the most important of these terms comes from an unexpected broken symmetry in the qubit potential. We confirm the theory by measuring the photon occupation of the resonator when transitions occur while varying the detuning between the qubit and resonator.

The use of ultrasound to assess fetal growth in a guinea pig model of fetal growth restriction

Fetal growth restriction (FGR) is a common and potentially severe pregnancy complication. Currently there is no treatment available. The guinea pig is an attractive model of human pregnancy as placentation is morphologically very similar between the species. Nutrient restriction of the dam creates growth-restricted fetuses while leaving an intact uteroplacental circulation, vital for evaluating novel therapies for FGR. Growth-restricted fetuses were generated by feeding Dunkin Hartley guinea pig dams 70% of ad libitum intake from four weeks before and throughout pregnancy. The effect of maternal nutrient restriction (MNR) on dams and fetuses was carefully monitored, and ultrasound measurements of pups collected. There was no difference in maternal weight at conception, however by five weeks post conception MNR dams were significantly lighter ( P < 0.05). MNR resulted in significantly smaller pup size from 0.6-0.66 gestation. Ultrasound is a powerful non-invasive tool for assessing the effect of therapeutic interventions on fetal growth, allowing longitudinal measurement of fetuses. This model and method yield data applicable to the human condition without the need for animal sacrifice and will be useful in the translation of therapies for FGR into the clinic.

Exploring Mbar shock conditions and isochorically heated aluminum at the Matter in Extreme Conditions end station of the Linac Coherent Light Source (invited)

Recent experiments performed at the Matter in Extreme Conditions end station of the Linac Coherent Light Source (LCLS) have demonstrated the first spectrally resolved measurements of plasmons from isochorically heated aluminum. The experiments have been performed using a seeded 8-keV x-ray laser beam as a pump and probe to both volumetrically heat and scatter x-rays from aluminum. Collective x-ray Thomson scattering spectra show a well-resolved plasmon feature that is down-shifted in energy by 19 eV. In addition, Mbar shock pressures from laser-compressed aluminum foils using velocity interferometer system for any reflector have been measured. The combination of experiments fully demonstrates the possibility to perform warm dense matter studies at the LCLS with unprecedented accuracy and precision.

Cortical thickness and inattention/hyperactivity symptoms in young children: a population-based study

BACKGROUND

While many neuroimaging studies have investigated the neurobiological basis of attention deficit hyperactivity disorder (ADHD), few have studied the neurobiology of attention problems in the general population. The ability to pay attention falls along a continuum within the population, with children with ADHD at one extreme of the spectrum and, therefore, a dimensional perspective of evaluating attention problems has an added value to the existing literature. Our goal was to investigate the relationship between cortical thickness and inattention and hyperactivity symptoms in a large population of young children.

METHOD

This study is embedded within the Generation R Study and includes 6- to 8-year-old children (n = 444) with parent-reported attention and hyperactivity measures and high-resolution structural imaging data. We investigated the relationship between cortical thickness across the entire brain and the Child Behavior Checklist Attention Deficit Hyperactivity Problems score.

RESULTS

We found that greater attention problems and hyperactivity were associated with a thinner right and left postcentral gyrus. When correcting for potential confounding factors and multiple testing, these associations remained significant.

CONCLUSIONS

In a large, population-based sample we showed that young (6- to 8-year-old) children who show more attention problems and hyperactivity have a thinner cortex in the region of the right and left postcentral gyrus. The postcentral gyrus, being the primary somatosensory cortex, reaches its peak growth early in development. Therefore, the thinner cortex in this region may reflect either a deviation in cortical maturation or a failure to reach the same peak cortical thickness compared with children without attention or hyperactivity problems.

Equilibration dynamics and conductivity of warm dense hydrogen

We investigate subpicosecond dynamics of warm dense hydrogen at the XUV free-electron laser facility (FLASH) at DESY (Hamburg). Ultrafast impulsive electron heating is initiated by a ≤ 300-fs short x-ray burst of 92-eV photon energy. A second pulse probes the sample via x-ray scattering at jitter-free variable time delay. We show that the initial molecular structure dissociates within (0.9 ± 0.2) ps, allowing us to infer the energy transfer rate between electrons and ions. We evaluate Saha and Thomas-Fermi ionization models in radiation hydrodynamics simulations, predicting plasma parameters that are subsequently used to calculate the static structure factor. A conductivity model for partially ionized plasma is validated by two-temperature density-functional theory coupled to molecular dynamic simulations and agrees with the experimental data. Our results provide important insights and the needed experimental data on transport properties of dense plasmas.