From One- to Two-Magnon Excitations in the S=3/2 Magnet ß-CaCr_{2}O_{4}.

We apply neutron spectroscopy to measure the magnetic dynamics in the S=3/2 magnet ß-CaCr_{2}O_{4} (T_{N}=21 K). The low-energy fluctuations, in the ordered state, resemble large-S linear spin waves from the incommensurate ground state. However, at higher energy transfers, these semiclassical and harmonic dynamics are replaced by an energy and momentum broadened continuum of excitations. Applying kinematic constraints required for energy and momentum conservation, sum rules of neutron scattering, and comparison against exact diagonalization calculations, we show that the dynamics at high-energy transfers resemble low-S one-dimensional quantum fluctuations. ß-CaCr_{2}O_{4} represents an example of a magnet at the border between classical Néel and quantum phases, displaying dual characteristics.

Stroke unit admission is associated with better outcome and lower mortality in patients with intracerebral hemorrhage.

BACKGROUND AND PURPOSE: There is no clear consensus among current guidelines on the preferred admission ward [i.e. intensive care unit (ICU) or stroke unit (SU)] for patients with intracerebral hemorrhage. Based on expert opinion, the American Heart Association and European Stroke Organization recommend treatment in neurological/neuroscience ICUs (NICUs) or SUs. The European Stroke Organization guideline states that there are no studies available directly comparing outcomes between ICUs and SUs. METHODS: We performed an observational study comparing outcomes of 10 811 consecutive non-comatose patients with intracerebral hemorrhage according to admission ward [ICUs, SUs and normal wards (NWs)]. Primary outcomes were the modified Rankin Scale score at discharge and intrahospital mortality. An additional analysis compared NICUs with SUs. RESULTS: Treatment outside an SU was associated with higher odds for an unfavorable outcome [ICU vs. SU: odds ratio (OR), 1.27; 95% confidence interval (CI), 1.09-1.46; NW vs. SU: OR, 1.28; 95% CI, 1.08-1.52] and higher odds for intrahospital mortality (ICU vs. SU: OR, 2.11; 95% CI, 1.75-2.55; NW vs. SU: OR, 1.52; 95% CI, 1.23-1.89). A subgroup analysis of severely affected patients treated in dedicated NICUs (vs. SUs) showed that they had a lower risk of a poor outcome (OR, 0.45; 95% CI, 0.26-0.79). CONCLUSIONS: Treatment in SUs was associated with better functional outcome and reduced mortality compared with ICUs and NWs. Our findings support the current guideline recommendations to treat patients with intracerebral hemorrhage in SUs or NICUs and suggest that some patients may further benefit from NICU treatment.

Anharmonic Magnon Excitations in Noncollinear and Charge-Ordered RbFe

RbFe^{2+}Fe^{3+}F_{6} is an example of a charge ordered antiferromagnet where iron sites, with differing valences, are structurally separated into two interpenetrating sublattices. The low temperature magnetically ordered Fe^{2+} (S=2) and Fe^{3+} (S=5/2) moments form a noncollinear orthogonal structure with the Fe^{3+} site displaying a reduced static ordered moment. Neutron spectroscopy on single crystals finds two distinct spin wave branches with a dominant coupling along the Fe^{3+} chain axis (b axis). High resolution spectroscopic measurements find an intense energy and momentum broadened magnetic band of scattering bracketing a momentum-energy region where two magnon processes are kinematically allowed. These anharmonic excitations are enhanced in this noncollinear magnet owing to the orthogonal spin arrangement.

From Ising Resonant Fluctuations to Static Uniaxial Order in Antiferromagnetic and Weakly Superconducting CeCo(In_{1-x}Hg_{x})_{5}(x=0.01).

CeCo(In_{0.990}Hg_{0.010})_{5} is a charge doped variant of the d-wave CoCoIn_{5} superconductor with coexistent antiferromagnetic and superconducting transitions occurring at T_{N}=3.4 and T_{c}=1.4 K, respectively. We use neutron diffraction and spectroscopy to show that the magnetic resonant fluctuations present in the parent superconducting phase are replaced by collinear c-axis magnetic order with three-dimensional Ising critical fluctuations. No low-energy transverse spin fluctuations are observable in this doping-induced antiferromagnetic phase and the dynamic resonant spectral weight predominately shifts to the elastic channel. Static (τ>0.2 ns) collinear Ising order is proximate to superconductivity in CeCoIn_{5} and is stabilized through hole doping with Hg.

Orphan Spins in the S=5/2 Antiferromagnet CaFe_{2}O_{4}.

CaFe_{2}O_{4} is an anisotropic S=5/2 antiferromagnet with two competing A (↑↑↓↓) and B (↑↓↑↓) magnetic order parameters separated by static antiphase boundaries at low temperatures. Neutron diffraction and bulk susceptibility measurements, show that the spins near these boundaries are weakly correlated and a carry an uncompensated ferromagnetic moment that can be tuned with a magnetic field. Spectroscopic measurements find these spins are bound with excitation energies less than the bulk magnetic spin waves and resemble the spectra from isolated spin clusters. Localized bound orphaned spins separate the two competing magnetic order parameters in CaFe_{2}O_{4}.

Solitary Magnons in the S=5/2 Antiferromagnet CaFe_{2}O_{4}.

CaFe_{2}O_{4} is a S=5/2 anisotropic antiferromagnet based upon zig-zag chains having two competing magnetic structures, denoted as the A (↑↑↓↓) and B (↑↓↑↓) phases, which differ by the c-axis stacking of ferromagnetic stripes. We apply neutron scattering to demonstrate that the competing A and B phase order parameters result in magnetic antiphase boundaries along c which freeze on the time scale of ∼1 ns at the onset of magnetic order at 200 K. Using high resolution neutron spectroscopy, we find quantized spin wave levels and measure 9 such excitations localized in regions ∼1-2 c-axis lattice constants in size. We discuss these in the context of solitary magnons predicted to exist in anisotropic systems. The magnetic anisotropy affords both competing A+B orders as well as localization of spin excitations in a classical magnet.

The effect of FES-rowing training on cardiac structure and function: pilot studies in people with spinal cord injury.

STUDY DESIGN: Two studies were conducted: Study-1 was cross-sectional; and Study-2 a longitudinal repeated measures design. OBJECTIVES: To examine the influence of functional electrical stimulation (FES) rowing training on cardiac structure and function in people with spinal cord injury (SCI). SETTING: A university sports science department and home-based FES-training. METHODS: Fourteen participants with C4-T10 SCI (American Spinal Injury Association Impairment Scale A or B) were recruited for the studies. Cardiac structure and function, and peak: oxygen uptake ([Vdot ]O2peak), power output (POpeak) and heart rate (HRpeak), were compared between two FES-untrained groups (male n=3, female n=3) and an FES-trained group (male n=3) in Study-1 and longitudinally assessed in an FES-naive group (male n=1, female n=4) in Study-2. Main outcome measures left ventricular-dimensions, volumes, mass, diastolic and systolic function, and [Vdot ]O2peak, POpeak and HRpeak. In Study-2, in addition to peak values, the [Vdot ]O2 sustainable over 30 min and the related PO and HR were also assessed. RESULTS: Sedentary participants with chronic SCI had cardiac structure and function at the lower limits of non-SCI normal ranges. Individuals with chronic SCI who habitually FES-row have cardiac structure and function that more closely resemble non-SCI populations. A programme of FES-rowing training improved cardiac structure and function in previously FES-naive people. CONCLUSION: FES-rowing training appears to be an effective stimulus for positive cardiac remodelling in people with SCI. Further work, with greater participant numbers, should investigate the impact of FES-rowing training on cardiac health in SCI. SPONSORSHIP: We thank the INSPIRE Foundation, UK, for funding these studies.

Acidosis Promotes Metastasis Formation by Enhancing Tumor Cell Motility.

The tumor microenvironment is characterized by hypoxia, acidosis as well as other metabolic and biochemical alterations. Its role in cancer progression is increasingly appreciated especially on invasive capacity and the formation of metastasis. The effect of acidosis on metastasis formation of two rat carcinoma cell lines was studied in the animal model. In order to analyze the pH dependency of different steps of metastasis formation, invasiveness, cell adhesion and migration of AT-1 prostate cancer cells as well as possible underlying cell signaling pathways were studied in vitro. Acidosis significantly increased the formation of lung metastases of both tumor cell lines in vivo. In vitro, extracellular acidosis neither enhanced invasiveness nor affected cell adhesion to a plastic or to an endothelial layer. However, cellular motility was markedly elevated at pH 6.6 and this effect was sustained even when extracellular pH was switched back to pH 7.4. When analyzing the underlying mechanism, a prominent role of ROS in the induction of migration was observed. Signaling through the MAP kinases ERK1/2 and p38 as well as Src family kinases was not involved. Thus, cancer cells in an acidic microenvironment can acquire enhanced motility, which is sustained even if the tumor cells leave their acidic microenvironment e.g. by entering the blood stream. This increase depended on elevated ROS production and may contribute to the augmented formation of metastases of acidosis-primed tumor cells in vivo.

Single to Multiquasiparticle Excitations in the Itinerant Helical Magnet CeRhIn(5).

CeRhIn(5) is an itinerant magnet where the Ce(3+) spins order in a simple helical phase. We investigate the spin excitations and observe sharp spin waves parameterized by a nearest-neighbor exchange, J(RKKY)=0.88±0.05 meV. At higher energies, the spin fluctuations are heavily damped, where single-quasiparticle excitations are replaced by a momentum- and energy-broadened continuum constrained by kinematics of energy and momentum conservation. The delicate energy balance between localized and itinerant characters results in the breakdown of the single-quasiparticle picture in CeRhIn(5).

[Projection of General Practitioner Care Demand at the Community Level]. / Projektion des Bedarfs an hausärztlicher Versorgung auf Gemeindeebene.

BACKGROUND: Within the next 8 years about 2 000 general practitioners (GPs) will be seeking a successor in the federal state of Baden-Württemberg, Germany. Both the small number of newly qualified GPs and the wish to work as an employee or in a group practice will lead to a situation in which about 500 practices will likely not find a successor. Using a single administrative district, the aim of this analysis was to develop a projection of the demand for GP health care at the community level. METHODS: Using the administrative district of Rottweil with its 21 communities, a community-based demographic forecast on the basis of current birth and death probabilities was performed. From the projected population structure, the demand for GP care in the year 2023 was derived under the assumption of unchanged age- and gender-specific numbers of GP visits. The anticipated deficit or, respectively, overrun of GPs at the community level was calculated as the difference between expected demand and number of GPs not retiring for age-related reasons. RESULTS: Until the year 2023 the demographic change will cause a shrinking population. However, with unchanged age- and gender-specific numbers of GP visits, a slightly higher demand of 0.6 GPs will occur as a result of population-aging. The expected age-related retirement of physicians will have a stronger impact on primary care demand than demography. Up to 32 (37%) GPs might need a successor. In addition to 4 communities today, this would result in another 5 communities not having a GP in 10 years. CONCLUSION: Communities that are at higher risk of GP shortage based on demographic changes and age of practicing GPs, can be identified by the approach described and applied here in order to implement targeted comprehensive community models of care.

[GP-centered health care in Baden-Württemberg, Germany: Results of a quantitative and qualitative evaluation]. / Hausarztzentrierte Versorgung in Baden-Württemberg : Ergebnisse einer qualitativen und querschnittlich quantitativen Evaluation.

BACKGROUND: GP-centered health care ("Hausarztzentrierte Versorgung", HzV)-the terms of which are described in § 73b of the Social Code Book V-came into effect in Baden-Württemberg, Germany, on 1 July 2008. The HzV is aimed at enhancing health care for patients with chronic diseases and complex health care needs (e.g., those requiring long-term care). OBJECTIVES: On the basis of four working packages (WP I-WP IV), the present paper examines the impact that GP-centered health care has had on patients insured by the "AOK" regional sickness fund and their GPs. WP I addresses the association between HzV participation and the corresponding health care utilization of patients on the basis of claims data. WP II looks at any changes that GPs and patients noticed were potentially attributable to HzV participation. WP III focuses on health care assistants in primary care ("Versorgungsassistenten in der Hausarztpraxis", VERAH). These assistants play a special role within the framework of the HzV. WP IV analyzes the quality of health care for patients aged 65 years and over, also on the basis of claims data. MATERIALS AND METHODS: A mixed methods design was used for this evaluation, and quantitative and qualitative approaches taken. This design enabled insights into the implementation of the HzV in regular health care to be obtained from different perspectives. RESULTS: Numerous positive associations between HzV participation and the variables of interest were observed for all WPs. These are presented in detail in the paper. CONCLUSION: The results obtained so far clearly support the continuation of HzV and associated evaluations.

Neutron-scattering evidence for a periodically modulated superconducting phase in the underdoped cuprate La1.905Ba0.095CuO4.

The role of antiferromagnetic spin correlations in high-temperature superconductors remains a matter of debate. We present inelastic neutron-scattering evidence that gapless spin fluctuations coexist with superconductivity in La1.905Ba0.095CuO4. Furthermore, we observe that both the low-energy magnetic spectral weight and the spin incommensurability are enhanced with the onset of superconducting correlations. We propose that the coexistence occurs through intertwining of spatial modulations of the pair wave function and the antiferromagnetic correlations. This proposal is also directly relevant to sufficiently underdoped La(2-x)Sr(x)CuO(4) and YBa(2)Cu(3)O(6+x).

Illicit substance use among university students from seven European countries: a comparison of personal and perceived peer use and attitudes towards illicit substance use.

OBJECTIVE: To compare European students' personal use and approval of illicit substance use with their perceptions of peer behaviours and attitudes, and investigate whether perceptions of peer norms are associated with personal use of illicit substances and attitudes. METHOD: This study used baseline data from the Social Norms Intervention for the prevention of Polydrug usE (SNIPE) project involving 4482 students from seven European countries in 2012. Students completed an online survey which included questions on personal and perceived peer illicit substance use and personal and perceived peer attitude towards illicit substances. RESULTS: 8.3% of students reported having used illicit substances at least once in their life. 49.7% of students perceived that the majority of their peers have used illicit substances more frequently than themselves. The perception was significantly associated with higher odds for personal illicit substance use (OR: 1.97, 95% CI: 1.53-2.54). The perception that the majority of peers approve illicit substance use was significantly associated with higher odds for personal approval of illicit substance use (OR: 3.47, 95% CI: 2.73-4.41). CONCLUSION: Students commonly perceived that their peers used illicit subtances more often than themselves. We found an association between the perceived peer norms/attitudes and reported individual behaviour/attitudes.

Can FES-rowing mediate bone mineral density in SCI: a pilot study.

STUDY DESIGN: A single case study. OBJECTIVES: To compare proximal tibia trabecular bone mineral density (BMD) of a participant with complete spinal cord injury (SCI), long-termed functional electrical stimulation-rowing (FES-R) trained, with previously reported SCI and non-SCI group norms. To estimate lower limb joint contact forces (JCFs) in the FES-R trained participant. SETTING: UK University and orthopaedic hospital research centre. METHODS: Bilateral proximal tibial trabecular BMD of the FES-R trained participant was measured using peripheral quantitative computerised tomography, and the data were compared with SCI and non-SCI groups. An instrumented four-channel FES-R system was used to measure the lower limb JCFs in the FES-R trained participant. RESULTS: Structurally, proximal tibial trabecular BMD was higher in the FES-R trained participant compared with the SCI group, but was less than the non-SCI group. Furthermore, left (184.7 mg cm(-3)) and right (160.7 mg cm(-3)) BMD were well above the threshold associated with non-traumatic fracture. The knee JCFs were above the threshold known to mediate BMD in SCI, but below threshold at the hip and ankle. CONCLUSION: As pathological fractures predominate in the distal femur and proximal tibia in chronic SCI patients, the fact that the FES-R trained participant's knee JCFs were above those known to partially prevent bone loss, suggests that FES-R training may provide therapeutic benefit. Although the elevated bilateral proximal tibial BMD of the FES-R participant provides circumstantial evidence of osteogenesis, this single case precludes any statement on the clinical significance. Further investigations are required involving larger numbers and additional channels of FES to increase loading at the hip and ankle.

Magnetic skin effect in Pb(Fe _{1/2}$Nb _{1/2}$)O3.

Relaxor-ferroelectrics display exceptional dielectric properties resulting from the underlying random dipolar fields induced by strong chemical inhomogeneity. An unusual structural aspect of relaxors is a skin-effect where the near-surface region in single crystals exhibit structures and critical phenomena that differ from the bulk. Relaxors are unique in that this skin effect extends over a macroscopic lengthscale of ∼100 µmwhereas usual surface layers only extend over a few unit cells (or ∼nm). We present a muon spectroscopy study of Pb(Fe_{1/2}Nb_{1/2})O3(PFN) which displays ferroelectric order, including many relaxor-like dielectric properties such as a frequency broadened dielectric response, and antiferromagnetism with spatially short-range polar correlations and hence can be termed a multiferroic. In terms of the magnetic behavior determined by the Fe3+(S=5/2,L ≈ 0) ions, PFN has been characterized as a unique example of a 'cluster spin-glass'. We use variable momentum muon spectroscopy to study the depth dependence of the slow magnetic relaxations in a large 1 cm3crystal of PFN. Zero-fieldpositivemuon spin relaxation is parameterized using a stretched exponential, indicative of a distribution of relaxation rates of the Fe3+spins. This bandwidth of frequencies changes as a function of muon momentum, indicative of a change in the Fe3+relaxation rates as a function of muon implantation depth in our single crystal. Usingnegativemuon elemental analysis, we find small-to-no measurable change in the Fe3+/Nb5+concentration with depth implying that chemical concentration alone cannot account for the change in the relaxational dynamics. PFN displays an analogous magnetic skin effect reported to exist in the structural properties of relaxor-ferroelectrics.

Performance of additional colonoscopies and yield of neoplasms within 3 years after screening colonoscopy: a historical cohort study.

BACKGROUND AND STUDY AIMS: After screening colonoscopy, additional colonoscopies may be required for adenoma surveillance or diagnostic reasons. The aim of the present study was to explore their utilization and findings in routine practice. PATIENTS AND METHODS: The study comprised an historical cohort of individuals participating in colonoscopy screening in 2006. Utilization and yield of neoplasms of additional colonoscopies performed in these individuals by the same physician ( < 6 months and 6 - 36 months after screening) between 2006 and 2009 were assessed using data of a colonoscopy quality assurance program in Bavaria, Germany. Screening including polypectomy, and short-term follow-up colonoscopy was assumed to have been completed within ≤ 6 months. Multivariate logistic regression was used to identify predictors of additional colonoscopy and advanced neoplasms (high risk adenoma or colorectal cancer [CRC]) among those with additional colonoscopy during the period of 6 - 36 months after screening. RESULTS: A total of 51 301 individuals undergoing screening colonoscopy were included. Of these, 10.1 % (95 % confidence interval [CI] 9.8 % - 10.3 %) had an additional colonoscopy performed by the same physician between 6 and 36 months after screening. The percentages of those with additional colonoscopy were 5.7 % (95 %CI 5.5 % - 5.9 %), 18.6 % (95 %CI 17.8 % - 19.4 %), and 33.7 % (95 %CI 32.2 % - 35.2 %) after negative screening, low risk adenoma at screening, and high risk adenoma at screening, respectively. The overall findings were negative colonoscopy, low risk adenoma, high risk adenoma, and CRC in 68.6 % (95 %CI 67.3 % - 69.8 %), 24.1 % (95 %CI 23.0 % - 25.3 %), 6.7 % (95 %CI 6.0 % - 7.4 %), and 0.6 % (95 %CI 0.4 % - 0.8 %), respectively. Younger age, male sex, screen-detected adenomas, inflammatory bowel disease, and early repeat colonoscopy within 6 months were predictors of additional colonoscopy. Older age, male sex, screen-detected adenomas, and surveillance indications were associated with increased risk of advanced neoplasms at post-screening colonoscopy. CONCLUSION: The results indicate frequent utilization of additional colonoscopies along with substantial adenoma yield in the first 3 years after screening colonoscopy.

Orbital character of the spin-reorientation transition in TbMn6Sn6.

Ferromagnetic (FM) order in a two-dimensional kagome layer is predicted to generate a topological Chern insulator without an applied magnetic field. The Chern gap is largest when spin moments point perpendicular to the kagome layer, enabling the capability to switch topological transport properties, such as the quantum anomalous Hall effect, by controlling the spin orientation. In TbMn6Sn6, the uniaxial magnetic anisotropy of the Tb3+ ion is effective at generating the Chern state within the FM Mn kagome layers while a spin-reorientation (SR) transition to easy-plane order above TSR = 310 K provides a mechanism for switching. Here, we use inelastic neutron scattering to provide key insights into the fundamental nature of the SR transition. The observation of two Tb excitations, which are split by the magnetic anisotropy energy, indicates an effective two-state orbital character for the Tb ion, with a uniaxial ground state and an isotropic excited state. The simultaneous observation of both modes below TSR confirms that orbital fluctuations are slow on magnetic and electronic time scales < ps and act as a spatially-random orbital alloy. A thermally-driven critical concentration of isotropic Tb ions triggers the SR transition.

Magnetic field splitting of the spin resonance in CeCoIn5.

Neutron scattering in strong magnetic fields is used to show the spin resonance in superconducting CeCoIn(5) (T(c)=2.3 K) is a doublet. The underdamped resonance (hΓ=0.069±0.019 meV) Zeeman splits into two modes at E(±)=hΩ(0)±αµ(B)µ(0)H with α=0.96±0.05. A linear extrapolation of the lower peak reaches zero energy at 11.2±0.5 T, near the critical field for the incommensurate "Q phase." Kenzelmann et al. [Science 321, 1652 (2008)] This, taken with the integrated weight and polarization of the low-energy mode (E(-)), indicates that the Q phase can be interpreted as a Bose condensate of spin excitons.

From incommensurate correlations to mesoscopic spin resonance in YbRh2Si2.

Spin fluctuations are reported near the magnetic field-driven quantum critical point in YbRh(2)Si(2). On cooling, ferromagnetic fluctuations evolve into incommensurate correlations located at q(0) = ±(δ,δ), with δ = 0.14 ± 0.04 r.l.u. At low temperatures, an in-plane magnetic field induces a sharp intradoublet resonant excitation at an energy E(0) = gµ(B)µ(0)H with g = 3.8 ± 0.2. The intensity is localized at the zone center, indicating precession of spin density extending ξ = 6 ± 2 Å beyond the 4f site.

Spin waves and revised crystal structure of honeycomb iridate Na2IrO3.

We report inelastic neutron scattering measurements on Na2IrO3, a candidate for the Kitaev spin model on the honeycomb lattice. We observe spin-wave excitations below 5 meV with a dispersion that can be accounted for by including substantial further-neighbor exchanges that stabilize zigzag magnetic order. The onset of long-range magnetic order below T(N)=15.3 K is confirmed via the observation of oscillations in zero-field muon-spin rotation experiments. Combining single-crystal diffraction and density functional calculations we propose a revised crystal structure model with significant departures from the ideal 90° Ir-O-Ir bonds required for dominant Kitaev exchange.