Disorder Induced Effects on the Critical Current Density of Iron Pnictide BaFe_1.8 Co_0.2 As_2 single crystals

Investigating the role of disorder in superconductors is an essential part of characterizing the fundamental superconducting properties as well as assessing potential applications of the material. In most cases, the information available on the defect matrix is poor, making such studies difficult, but the situation can be improved by introducing defects in a controlled way, as provided by neutron irradiation. In this work, we analyze the effects of neutron irradiation on a Ba(Fe$_{1-x}$Co$_x$)$_2$As$_2$ single crystal. We mainly concentrate on the magnetic properties which were determined by magnetometry. Introducing disorder by neutron irradiation leads to significant effects on both the reversible and the irreversible magnetic properties, such as the transition temperature, the upper critical field, the anisotropy, and the critical current density. The results are discussed in detail by comparing them with the properties in the unirradiated state.Comment: accepted for Ph

Pasteurella multocida infections: Report of 34 cases and review of the literature

Pasteurella multocida, a small gram-negative coccobacillus, is part of the normal oral flora of many animals, including the cat and dog. P. multocida is a major pathogen in wound infections due to animal bites and can cause cellutitis, abscess, osteomyelitis, septic arthritis, or a variety of other infectious syndromes (Table 1). Over the years, P. multocida has been the subject of a number of short general reviews (74, 80, 91, 96, 158). More recently, reviews have focused on selected aspects of P. multocida infection including meningitis (44), empyema (112), spontaneous bacterial peritonitis (160), bone and joint infections (56), and septicemia (111). A large series of cases with a comprehensive review, however, has not been published. We therefore report here 34 cases from the Massachusetts General Hospital and review the English literature

Mean-atom-trajectory model for the velocity autocorrelation function of monatomic liquids

We present a model for the motion of an average atom in a liquid or supercooled liquid state and apply it to calculations of the velocity autocorrelation function $Z(t)$ and diffusion coefficient $D$. The model trajectory consists of oscillations at a distribution of frequencies characteristic of the normal modes of a single potential valley, interspersed with position- and velocity-conserving transits to similar adjacent valleys. The resulting predictions for $Z(t)$ and $D$ agree remarkably well with MD simulations of Na at up to almost three times its melting temperature. Two independent processes in the model relax velocity autocorrelations: (a) dephasing due to the presence of many frequency components, which operates at all temperatures but which produces no diffusion, and (b) the transit process, which increases with increasing temperature and which produces diffusion. Because the model provides a single-atom trajectory in real space and time, including transits, it may be used to calculate all single-atom correlation functions.Comment: LaTeX, 8 figs. This is an updated version of cond-mat/0002057 and cond-mat/0002058 combined Minor changes made to coincide with published versio

Behandlung von isolierten Olekranonfrakturen: Perkutane Doppelschraubenosteosynthese vs. konventionelle Zuggurtung

Zusammenfassung: Hintergrund: Olekranonfrakturen gehören mit 7-10 % zu den mittelhäufigen Brüchen des Erwachsenen. In der Regel werden diese Frakturen operativ mittels konventioneller Zuggurtungsosteosynthese behandelt. Eine perkutane minimal-invasive Doppelschraubenosteosynthese ist eine alternative Technik bei einfacher Zwei-Fragment-Fraktur mit möglichen Vorteilen für diese selektierten Patienten. Patienten und Methode: Es wurden 13Patienten mit einer isolierten Olekranonfraktur vom TypA nach Schatzker-Schmelling mittels perkutaner Doppelschraubenosteosynthese behandelt und in diese prospektive Studie eingeschlossen. Das Durchschnittsalter betrug 43,6 ± 11,0Jahre. Die intra- und postoperativen Komplikationen wurden erfasst. Die funktionellen Ergebnisse wurden nach einer mittleren Nachuntersuchungszeit von 38,2 ± 11,5Monaten mittels Quick-DASH ("disability of shoulder, arms and hand questionnaire") erfasst. Die Ergebnisse wurden mit einer Kontrollgruppe verglichen, bestehend aus 26Patienten, welche beim gleichen Frakturtyp mit der konventionellen Zuggurtungsosteosynthese behandelt wurden. Ergebnisse: In beiden Gruppen kam es zu keinen intraoperativen Komplikationen. In der Gruppe der perkutanen Doppelschraubenosteosynthese war die Narbe signifikant kürzer (2,4 ± 0,4 vs. 11,0 ± 1,8cm; p < 0,001), das Osteosynthesematerial musste signifikant weniger häufig entfernt werden (38,5 % vs. 73,1 %). Nach einer Mindestnachbeobachtungszeit von 2 (Mittelwert 3,2) Jahren wurden in beiden Gruppen vergleichbare funktionelle Ergebnisse erzielt (Quick-DASH-Score: 2,3 vs. 0,0Punkte; p = 0,155), wobei der Bewegungsumfang in der Gruppe der Doppelschraubenosteosynthese signifikant größer für Extension/Flexion (145 ° vs. 130 °; p < 0,001) und Pro/-Supination (165 ° vs. 155 °; p < 0,001) war als in der Gruppe der konventionellen Zuggurtung. Schlussfolgerung: Bei Patienten mit einer einfachen Olekranonfraktur vom TypA nach Schatzker-Schmelling liefert die perkutane Doppelschraubenosteosynthese vergleichbare Ergebnisse im DASH-Score im Vergleich zum Goldstandard, hat jedoch den Vorteil einer geringeren Revisionsrate mit besserer Beweglichkeit und Kosmetik

Influence of substrate and sand characteristics on Roman cement mortar performance

When formulating repair mortars standard test specimens should be used with caution as these cannot be considered representative of samples of mortars collected on site. This work reports an approach to repair mortar formulation which takes into account the influence of porous substrates, sand characteristics and mortar thickness on the properties of both fresh and hardened Roman cement mortars. It is shown that mortars cast on a dry absorbent substrate show modified properties such as increased strength and decreased water absorption coefficient, the degree of which is a function of sand grading and surface characteristics, sample thickness and substrate sorptivity

The ROAM/EORTC-1308 trial: Radiation versus Observation following surgical resection of Atypical Meningioma: study protocol for a randomised controlled trial

BACKGROUND Atypical meningiomas are an intermediate grade brain tumour with a recurrence rate of 39-58 %. It is not known whether early adjuvant radiotherapy reduces the risk of tumour recurrence and whether the potential side-effects are justified. An alternative management strategy is to perform active monitoring with magnetic resonance imaging (MRI) and to treat at recurrence. There are no randomised controlled trials comparing these two approaches. METHODS/DESIGN A total of 190 patients will be recruited from neurosurgical/neuro-oncology centres across the United Kingdom, Ireland and mainland Europe. Adult patients undergoing gross total resection of intracranial atypical meningioma are eligible. Patients with multiple meningioma, optic nerve sheath meningioma, previous intracranial tumour, previous cranial radiotherapy and neurofibromatosis will be excluded. Informed consent will be obtained from patients. This is a two-stage trial (both stages will run in parallel): Stage 1 (qualitative study) is designed to maximise patient and clinician acceptability, thereby optimising recruitment and retention. Patients wishing to continue will proceed to randomisation. Stage 2 (randomisation) patients will be randomised to receive either early adjuvant radiotherapy for 6 weeks (60 Gy in 30 fractions) or active monitoring. The primary outcome measure is time to MRI evidence of tumour recurrence (progression-free survival (PFS)). Secondary outcome measures include assessing the toxicity of the radiotherapy, the quality of life, neurocognitive function, time to second line treatment, time to death (overall survival (OS)) and incremental cost per quality-adjusted life year (QALY) gained. DISCUSSION ROAM/EORTC-1308 is the first multi-centre randomised controlled trial designed to determine whether early adjuvant radiotherapy reduces the risk of tumour recurrence following complete surgical resection of atypical meningioma. The results of this study will be used to inform current neurosurgery and neuro-oncology practice worldwide. TRIAL REGISTRATION ISRCTN71502099 on 19 May 2014

Gutzwiller-Correlated Wave Functions: Application to Ferromagnetic Nickel

Ferromagnetic Nickel is the most celebrated iron group metal with pronounced discrepancies between the experimental electronic properties and predictions of density functional theories. In this work, we show in detail that the recently developed multi-band Gutzwiller theory provides a very good description of the quasi-particle band structure of nickel. We obtain the correct exchange splittings and we reproduce the experimental Fermi-surface topology. The correct (111)-direction of the magnetic easy axis and the right order of magnitude of the magnetic anisotropy are found. Our theory also reproduces the experimentally observed change of the Fermi-surface topology when the magnetic moment is oriented along the (001)-axis. In addition to the numerical study, we give an analytical derivation for a much larger class of variational wave-functions than in previous investigations. In particular, we cover cases of superconductivity in multi-band lattice systems.Comment: 35 pages, 3 figure