Measurement of Identical Particle Entanglement and the Influence of Antisymmetrization.

We explore the relationship between symmetrization and entanglement through measurements on few-particle systems in a multiwell potential. In particular, considering two or three trapped atoms, we measure and distinguish correlations arising from two different physical origins: antisymmetrization of the fermionic wave function and interaction between particles. We quantify this through the entanglement negativity of states, and the introduction of an antisymmetric negativity, which allows us to understand the role that symmetrization plays in the measured entanglement properties. We apply this concept both to pure theoretical states and to experimentally reconstructed density matrices of two or three mobile particles in an array of optical tweezers.

Density Oscillations Induced by Individual Ultracold Two-Body Collisions.

Access to single-particle momenta provides new means of studying the dynamics of a few interacting particles. In a joint theoretical and experimental effort, we observe and analyze the effects of a finite number of ultracold two-body collisions on the relative and single-particle densities by quenching two ultracold atoms with an initial narrow wave packet into a wide trap with an inverted aspect ratio. The experimentally observed spatial oscillations of the relative density are reproduced by a parameter-free zero-range theory and interpreted in terms of cross-dimensional flux. We theoretically study the long-time dynamics and find that the system does not approach its thermodynamic limit. The setup can be viewed as an advanced particle collider that allows one to watch the collision process itself.

Realization of a Strongly Interacting Fermi Gas of Dipolar Atoms.

We realize a two-component dipolar Fermi gas with tunable interactions, using erbium atoms. Employing a lattice-protection technique, we selectively prepare deeply degenerate mixtures of the two lowest spin states and perform high-resolution Feshbach spectroscopy in an optical dipole trap. We identify a comparatively broad Feshbach resonance and map the interspin scattering length in its vicinity. The Fermi mixture shows a remarkable collisional stability in the strongly interacting regime, providing a first step towards studies of superfluid pairing, crossing from Cooper pairs to bound molecules, in presence of dipole-dipole interactions.

European consensus on the concepts and measurement of the pathophysiological neuromuscular responses to passive muscle stretch.

BACKGROUND AND PURPOSE: To support clinical decision-making in central neurological disorders, a physical examination is used to assess responses to passive muscle stretch. However, what exactly is being assessed is expressed and interpreted in different ways. A clear diagnostic framework is lacking. Therefore, the aim was to arrive at unambiguous terminology about the concepts and measurement around pathophysiological neuromuscular response to passive muscle stretch. METHODS: During two consensus meetings, 37 experts from 12 European countries filled online questionnaires based on a Delphi approach, followed by plenary discussion after rounds. Consensus was reached for agreement ≥75%. RESULTS: The term hyper-resistance should be used to describe the phenomenon of impaired neuromuscular response during passive stretch, instead of for example 'spasticity' or 'hypertonia'. From there, it is essential to distinguish non-neural (tissue-related) from neural (central nervous system related) contributions to hyper-resistance. Tissue contributions are elasticity, viscosity and muscle shortening. Neural contributions are velocity dependent stretch hyperreflexia and non-velocity dependent involuntary background activation. The term 'spasticity' should only be used next to stretch hyperreflexia, and 'stiffness' next to passive tissue contributions. When joint angle, moment and electromyography are recorded, components of hyper-resistance within the framework can be quantitatively assessed. CONCLUSIONS: A conceptual framework of pathophysiological responses to passive muscle stretch is defined. This framework can be used in clinical assessment of hyper-resistance and will improve communication between clinicians. Components within the framework are defined by objective parameters from instrumented assessment. These parameters need experimental validation in order to develop treatment algorithms based on the aetiology of the clinical phenomena.

[Is family history dispensable?]. / Ist die Familienanamnese verzichtbar?

As an element of risk assessment in applications for life insurance, family medical history has a particular significance since given impairments can occur more frequently within families. Family history is not only genetic in nature. Depending on the impairment, it is also explained by external factors. There has been little literature on this topic so far, although the spectrum of family history-related impairments is very large, and their effect is highly dependent on the type of product. This paper presents a new method for assessing the effects of information contained in family history on claims, based on typical age patterns for German life insurance products (life, disability and long term care insurance), using the example of breast cancer and schizophrenia. This method helps life insurers to better understand what impact questions on family history during the stage of application have on the risk. Thus, the study contributes to the often discussed question on how essential questions on family history are.

Development of non-verbal intellectual capacity in school-age children with cerebral palsy.

BACKGROUND: Children with cerebral palsy (CP) are at greater risk for a limited intellectual development than typically developing children. Little information is available which children with CP are most at risk. This study aimed to describe the development of non-verbal intellectual capacity of school-age children with CP and to examine the association between the development of non-verbal intellectual capacity and the severity of CP. METHODS: A longitudinal analysis in a cohort study was performed with a clinic-based sample of children with CP. Forty-two children were assessed at 5, 6 and 7 years of age, and 49 children were assessed at 7, 8 and 9 years of age. Non-verbal intellectual capacity was assessed by Raven's Coloured Progressive Matrices (RCPM). Severity of CP was classified by the Gross Motor Function Classification System, type of motor impairment and limb distribution. manova for repeated measurements was used to analyse time effects and time × group effects on both RCPM raw scores and RCPM intelligence quotient scores. RESULTS: The development of non-verbal intellectual capacity was characterised by a statistically significant increase in RCPM raw scores but no significant change in RCPM intelligence quotient scores. The development of RCPM raw scores was significantly associated with the severity of CP. Children with higher levels of gross motor functioning and children with spastic CP showed greater increase in raw scores than children with lower levels of gross motor functioning and children with dyskinetic CP. CONCLUSIONS: Children with CP aged between 5 and 9 years show different developmental trajectories for non-verbal intellectual capacity, which are associated with the severity of CP. The development of non-verbal intellectual capacity in children with less severe CP seems to resemble that of typically developing children, while children with more severe CP show a limited intellectual development compared to typically developing children.

Effect of selective dorsal rhizotomy on gait in children with bilateral spastic paresis: kinematic and EMG-pattern changes.

INTRODUCTION: Selective dorsal rhizotomy (SDR) is an effective treatment for reducing spasticity and improving gait in children with spastic cerebral palsy. Data concerning muscle activity changes after SDR treatment are limited. PATIENTS AND METHODS: In 30 children who underwent SDR a gait analysis was performed before and 12-24 months postoperatively. Subjects walked on a 10-m walkway at comfortable walking speed. Biplanar video was registered and surface EMG was recorded. Sagittal knee angles were measured from video and observational gait assessments were performed using the Edinburgh gait assessment scale (EGAS). RESULTS: The EGAS significantly improved after SDR (p<0.001). There were significant improvements of the knee angle kinematics (p<0.001). Only slight changes in EMG activity were observed. The activity of the m. gastrocnemius (GM) decreased and a late peak appeared in stance, the activity of the m. semitendinosus (ST) increased in stance. The activity of the m. rectus femoris (RF) decreased in swing. CONCLUSION: SDR improved overall gait performance but EMG changes were only slight. Better timing of the GM in stance and reduced activity of RF in swing may have increased knee flexion in swing. Reduced hamstrings spasticity may have led to postural instability in the hip.

Course of behaviour problems of children with cerebral palsy: the role of parental stress and support.

BACKGROUND: Cerebral palsy (CP) is a well-recognized neurodevelopmental condition persisting through the lifespan. In many individuals with CP, motor disorders are accompanied by other disturbances, including emotional and behavioural problems. Little is known on the course of such problems, also in relation to possible exacerbating or mitigating factors. Aims of this study were to test whether parental stress and support, apart from the severity of CP of the child, played a significant role in the course of behaviour problems. METHOD: The participants aged 9, 11 and 13 were assessed (baseline) and followed up after 1, 2 and 3 years. Situational and relational sources of support and stress for the primary caregiver were rated with a questionnaire: (CBCL), behaviour problems with the Child Behaviour Checklist. Physicians rated motor ability using the Gross Motor Function Classification System. RESULTS: Behaviour problems of children with CP started significantly higher than in the general population, but diminished over the 3-year period. Older children showed less problems overall, and girls showed less externalizing problems than boys. Children with the most severe CP had more externalizing problems; effects on internalizing problems were not significant. Across time, an excess of stress vs. support related to parents' socio-economic and living situation and to parents' social relationships was positively related to total behaviour problems, internalizing and externalizing behaviours of children. CONCLUSIONS: Levels of behaviour problems are elevated but diminish during adolescence for children with CP. Severity of CP plays a role as well as the family context in terms of the stress and support that caregivers experience.

To see or not to see?...that is the question. An analysis of out-patient follow-up arrangements and non-attendance in a community paediatric population.

OBJECTIVE: To investigate the relationship between the number of outpatient appointments made; the distance traveled to attend these and the proportion of these appointments missed. DESIGN: Retrospective Cohort Study. SETTING: Community Paediatrics. PARTICIPANTS: Eighteen pre-school children on the Special Needs Register. RESULTS: With an increase in the number of appointments made and the distances involved in attending these, the number of missed appointments tends to increase. CONCLUSIONS: We need to educate parents as to the importance of follow-up, include families in decision making about appointments and rationalize the number of appointments made.

Ankle foot orthoses in cerebral palsy: Effects of ankle stiffness on trunk kinematics, gait stability and energy cost of walking.

In children with cerebral palsy (CP), rigid ventral shell ankle-foot orthoses (vAFOs) are often prescribed to reduce excessive knee flexion in stance and lower the energy cost of walking (ECW). However, how vAFOs affect ECW is a complex issue, as vAFOs may have an impact on lower limb biomechanics, upper body movements, and balance. Besides, the vAFO's biomechanical effect have been shown to be dependent on its stiffness around the ankle joint. We examined whether vAFO stiffness influences trunk movements and gait stability in CP, and whether there is a relationship between these factors and ECW. Fifteen children with spastic CP were prescribed vAFOs. Stiffness was varied into a rigid, stiff and flexible configuration. At baseline (shoes-only) and for each vAFO stiffness configuration, 3D-gait analyses and ECW-tests were performed. From the gait analyses, we derived trunk tilt, lateroflexion, and rotation range of motion (RoM) and the mediolateral and anteroposterior Margins of Stability (MoS) and their variability as measures of gait stability. With the ECW-test we determined the netEC. We found that wearing vAFOs significantly increased trunk lateroflexion (Wald χ2 = 33.7, p < 0.001), rotation RoM (Wald χ2 = 20.5, p < 0.001) and mediolateral gait instability (Wald χ2 = 10.4, p = 0.016). The extent of these effects partly depended on the stiffness of the vAFO. Significant relations between trunk movements, gait stability and ECW were found r = 0.57-0.81, p < 0.05), which indicates that trunk movements and gait stability should be taken into account when prescribing vAFOs to improve gait in children with CP walking with excessive knee flexion.

Parents' reactions to the diagnosis of cerebral palsy: associations between resolution, age and severity of disability.

BACKGROUND: For parents, receiving a diagnosis, typically in early childhood, that their child has cerebral palsy may conjure up high distress and anxiety. Resolution of these initial reactions may help parents to focus on the challenges and needs of their children. AIMS: of the study were to test whether parents of older children displayed resolution more often than parents of younger children, and whether parents of children with less severe cerebral palsy also showed more resolution. METHOD: Resolution of reactions to diagnosis was assessed with the Reaction to Diagnosis Interview, in a clinic-based sample of 255 parents of children with cerebral palsy aged between 1.4 and 17.3 years. Physicians rated motor ability using the Gross Motor Function Classification System. RESULTS: Overall, the responses of 81.6% of the parents were predominantly indicative of resolution. Unresolved reactions were significantly more often found among parents of younger children and parents of children with more severe motor disabilities. Among parents of teenage children, resolution was more often apparent from a focus on action to better the lives of their children, whereas in parents of younger children, it was more apparent from their focus on constructive thoughts and information seeking. CONCLUSIONS: Given time, the large majority of parents may resolve their reactions to the diagnosis that their child has cerebral palsy. Parents of the most severely affected children may need specific support which, given the age trends, might be aimed at different resolution processes for parents of younger and older children.

[Decision analysis--a novel approach for calculating the cost-efficiency of medical tests]. / Entscheidungsanalyse--ein neuer Ansatz zur Kosteneffizienz- berechnung medizinischer Tests.

Before issuing an insurance policy (e.g. life, disability, critical illness), insurers will usually carry out a medical risk assessment in order to prevent adverse selection. Often, the health questions in the application form will not be sufficient for this purpose since most applicants are not well-versed in medical science and terminology. If the insurer needs additional medical information such as a private medical attendant's report or current laboratory tests, however, costs will be incurred, which usually have to be paid by the insurer. What is the minimum sum insured which makes it worthwhile for the insurer to conduct certain screening tests, for example? Both the costs of medical screening and the associated savings are difficult to measure and involve a variety of different factors. Moreover, most parameters can only be estimated with limited accuracy. Therefore, we have developed a new calculation model using a decision-analysis approach. The new model makes it possible to analyse complex situations while taking into account the uncertainty of parameter estimation. Our findings show that in Germany, for instance, current sum thresholds for older applicants could in many cases be lowered and would still be cost-effective.

Observation of Roton Mode Population in a Dipolar Quantum Gas.

The concept of a roton, a special kind of elementary excitation, forming a minimum of energy at finite momentum, has been essential to understand the properties of superfluid 4He 1. In quantum liquids, rotons arise from the strong interparticle interactions, whose microscopic description remains debated 2. In the realm of highly-controllable quantum gases, a roton mode has been predicted to emerge due to magnetic dipole-dipole interactions despite of their weakly-interacting character 3. This prospect has raised considerable interest 4-12; yet roton modes in dipolar quantum gases have remained elusive to observations. Here we report experimental and theoretical studies of the momentum distribution in Bose-Einstein condensates of highly-magnetic erbium atoms, revealing the existence of the long-sought roton mode. Following an interaction quench, the roton mode manifests itself with the appearance of symmetric peaks at well-defined finite momentum. The roton momentum follows the predicted geometrical scaling with the inverse of the confinement length along the magnetisation axis. From the growth of the roton population, we probe the roton softening of the excitation spectrum in time and extract the corresponding imaginary roton gap. Our results provide a further step in the quest towards supersolidity in dipolar quantum gases 13.

Is intrapartum asphyxia preventable?

The contribution of intrapartum events to asphyxia-related mortality and morbidity and the degree to which it may be prevented are controversial. We examined trends in asphyxia-related mortality and morbidity in a single large regional perinatal centre. Between 1994 and 2005, the rate of asphyxia fell from 2.86/1000 births in 1994 to 0.91/1000 births in 2005 (P < 0.001). Hypoxic-ischaemic encephalopathy of all grades fell from 2.41 to 0.77/1000 live births (P < 0.001). This substantial and steady fall in the rate of asphyxia-related mortality and morbidity over a 12-year period suggests that a significant proportion of cases of intrapartum asphyxia may be preventable.

The distribution of apolipoprotein E alleles in Scottish perinatal deaths.

BACKGROUND: The apolipoprotein E (ApoE) polymorphism has been well studied in the adult human population, in part because the e4 allele is a known risk factor for Alzheimer's disease. Little is known of the distribution of ApoE alleles in newborns, and their association with perinatal brain damage has not been investigated. METHODS: ApoE genotyping was undertaken in a Scottish cohort of perinatal deaths (n = 261), some of whom had prenatal brain damage. The distribution of ApoE alleles in perinatal deaths was compared with that in healthy liveborn infants and in adults in Scotland. RESULTS: ApoE e2 was over-represented in 251 perinatal deaths (13% v 8% in healthy newborns, odds ratio (OR) = 1.63, 95% confidence interval (CI) 1.13 to 2.36 and 13% v 8% in adults, OR = 1.67, 95% CI 1.16 to 2.41), both in liveborn and stillborn perinatal deaths. In contrast, the prevalence of ApoE e4 was raised in healthy liveborn infants (19%) compared with stillbirths (13%, OR = 1.59, 95% CI 1.11 to 2.26) and with adults (15%, OR = 1.35, 95% CI 1.04 to 1.76). However, no correlation was found between ApoE genotype and the presence or absence of perinatal brain damage. CONCLUSIONS: This study shows a shift in ApoE allelic distribution in early life compared with adults. The raised prevalence of ApoE e2 associated with perinatal death suggests that this allele is detrimental to pregnancy outcome, whereas ApoE e4 may be less so. However, ApoE genotype did not appear to influence the vulnerability for perinatal hypoxic/ischaemic brain damage, in agreement with findings in adult brains and in animal models.

New E-beam-initiated hyaluronan acrylate cryogels support growth and matrix deposition by dermal fibroblasts.

Cryogels made of components of natural extracellular matrix components are potent biomaterials for bioengineering and regenerative medicine. Human dermal fibroblasts are key cells for tissue replacement during wound healing. Thus, any biomaterial for wound healing applications should enable growth, differentiation and matrix synthesis by these cells. Cryogels are highly porous scaffolds consisting of a network of interconnected pores. Here, we used a novel group of cryogels generated from acrylated hyaluronan where the polymerization was initiated by accelerated electrons (E-beam). This novel procedure omits any toxic polymerization initiators and results in sterile, highly elastic scaffolds with adjustable pore size, excellent swelling and low flow resistance properties. We show that these cryogels are effective 3D-substrates for long-term cultures of human dermal fibroblasts in vitro. The cells proliferate for at least 28days throughout the cryogels and deposit their own matrix in the pores. Moreover, key modulators of dermal fibroblasts during wound healing like TGFß and PDGF efficiently stimulated the expression of wound healing-relevant genes. In conclusion, electron beam initiated cryogels of acrylated hyaluronan represent a functional and cell compatible biomaterial that could be adapted for special wound healing applications by further functionalization.

Effect of selective dorsal rhizotomy on daily care and comfort in non-walking children and adolescents with severe spasticity.

BACKGROUND: In non-walking children with severe spasticity, daily care can be difficult and many patients suffer from pain. Selective dorsal rhizotomy (SDR) reduces spasticity in the legs, and therefore has the potential to improve daily care and comfort. AIM: To examine effects of SDR on daily care and comfort in non-walking children with severe spasticity due to different underlying neurological conditions. METHODS: Medical history, changes in daily care and comfort and satisfaction with outcome were assessed retrospectively in non-walking children who underwent SDR in our center, with a mean follow-up of 1y 7m (range 11m-4y 3m). All eligible patients (n = 24, years 2009-2014) were included. RESULTS: Mean age at SDR was 12y 4m (SD 4y 3m, range 2y 8m-19y 3m). Associated orthopaedic problems were frequent. Seven patients underwent scoliosis correction in the same session. Most improvements were reported in dressing (n = 16), washing (n = 12) and comfort (n = 10). Median score for satisfaction was 7 on a scale of 10 (range 1-9). SDR resulted in reduction of spasticity in leg muscles. In nine patients dystonia was recorded post-operatively, mainly in children with congenital malformations and syndromes. INTERPRETATION: SDR is a single event intervention that can improve daily care and comfort in non-walking children with severe spasticity, and can safely be combined with scoliosis correction. Despite the improvements, satisfaction is variable. Careful attention is necessary for risk factors for dystonia, which may be unmasked after SDR.

Brain damage and axonal injury in a Scottish cohort of neonatal deaths.

Despite the clinical and medicolegal significance attached to perinatal asphyxia, the neuropathological basis of this condition remains obscure. There are very few studies in the literature which correlate the pathological findings in neonatal brains with detailed epidemiological data, and none which are population based. In a Scotland-wide study of neonatal deaths, 70 brains have been examined. On the basis of glial and macrophage reactions, we previously identified infants with putative antepartum brain damage in this cohort and have related these reactions to signs of birth asphyxia. The present study explores the extent of neuronal/axonal injury in these infants since this is likely to be the basis for neurological deficits in surviving infants. We have also investigated these brains for beta-amyloid precursor protein (betaAPP) positivity to determine whether this is a useful marker of neuronal injury in neonates. Neuronal eosinophilia and karyorrhexes were detected in 43% and 27% of the cohort, respectively; maximally in the subiculum and ventral pons, but often present elsewhere. White matter damage was detected in 24% of cases but without classic cystic lesions of periventricular leucomalacia. betaAPP positivity was present in neuronal soma in 52% of cases and, in axons, in 27% of cases, and was seen from as early as 25-weeks gestation. Axonal bulbs were clearly delineated by betaAPP positivity and were usually located in the cerebral white matter and internal capsule, and infrequently in the brain stem. Although white matter damage and betaAPP axonal positivity were often detected in the same cases (P = 0.034), these features also occurred independently of each other. Both neuronal karyorrhexes and white matter betaAPP positivity were significantly correlated with the features of birth asphyxia, particularly a history of seizures. Immunocytochemistry for both betaAPP and glial fibrillary acidic protein proved useful in detecting neuropathological features which escaped detection on routine examination, particularly in preterm infants. The presence together of recent and older damage in individual brains suggests that there is an ongoing neuronal response to cerebral insults. We find that betaAPP is a useful marker of white matter damage in the neonatal brain. Immunopositivity for betaAPP in these circumstances is not attributable to inflicted or accidental trauma. While birth-related trauma cannot be ruled out, hypoxia/ischaemia is a likely cause in these infants. However, the exact pathogenesis of neuronal/axonal injury in the neonatal brain remains unclear.

Patterns of age mixing and sexually transmitted infections.

Age mixing is an important indicator of sexually transmitted infection (STI) prevalence in partner pools. We use the 1995 National Survey of Family Growth (NSFG), a nationally representative sample of reproductive-age American women, to assess the extent of age mixing and to examine the association between age mixing and STI history. Almost half (48%) of the women in our sample report partnerships with much older or younger men. The likelihood of an STI diagnosis or receipt of STI care (test or treatment) increases as the age difference increases among adolescents. Women in their mid-to-late 20s with much younger partners report receipt of STI care more often than other women. Report of an STI diagnosis is more common among older women with much younger partners than among others of their age. Age-mixing information may be helpful for screening initiatives and targeting interventions aimed at decreasing STI rates, their sequelae, and STI transmission.

Resummation of QED perturbation series by sequence transformations and the prediction of perturbative coefficients

We propose a method for the resummation of divergent perturbative expansions in quantum electrodynamics and related field theories. The method is based on a nonlinear sequence transformation and uses as input data only the numerical values of a finite number of perturbative coefficients. The results obtained in this way are for alternating series superior to those obtained using Pade approximants. The nonlinear sequence transformation fulfills an accuracy-through-order relation and can be used to predict perturbative coefficients. In many cases, these predictions are closer to available analytic results than predictions obtained using the Pade method.