2,359 research outputs found

    The Proper Motion of PSR J0205+6449 in 3C 58

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    We report on sensitive phase-referenced and gated 1.4-GHz VLBI radio observations of the pulsar PSR J0205+6449 in the young pulsar-wind nebula 3C 58, made in 2007 and 2010. We employed a novel technique where the ~105-m Green Bank telescope is used simultaneously to obtain single-dish data used to determine the pulsar's period as well as to obtain the VLBI data, allowing the VLBI correlation to be gated synchronously with the pulse to increase the signal-to-noise. The high timing noise of this young pulsar precludes the determination of the proper motion from the pulsar timing. We derive the position of the pulsar accurate at the milliarcsecond level, which is consistent with a re-determined position from the Chandra X-ray observations. We reject the original tentative optical identification of the pulsar by Shearer and Neustroev (2008), but rather identify a different optical counterpart on their images, with R-band magnitude ~24. We also determine an accurate proper motion for PSR J0205+6449 of (2.3 +- 0.3) mas/yr, corresponding to a projected velocity of only (35 +- 6) km/s for a distance of 3.2 kpc, at p.a. -38 deg. This projected velocity is quite low compared to the velocity dispersion of known pulsars of ~200 km/s. Our measured proper motion does not suggest any particular kinematic age for the pulsar.Comment: 10 pages, 7 figures; accepted for publication in MNRA

    Spin reorientation in Na-doped BaFe2_2As2_2 studied by neutron diffraction

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    We have studied the magnetic ordering in Na doped BaFe2_2As2_2 by unpolarized and polarized neutron diffraction using single crystals. Unlike previously studied FeAs-based compounds that magnetically order, Ba1x_{1-x}Nax_xFe2_2As2_2 exhibits two successive magnetic transitions: For x=0.35 upon cooling magnetic order occurs at \sim70\ K with in-plane magnetic moments being arranged as in pure or Ni, Co and K-doped BaFe2_2As2_2 samples. At a temperature of \sim46\ K a second phase transition occurs, which the single-crystal neutron diffraction experiments can unambiguously identify as a spin reorientation. At low temperatures, the ordered magnetic moments in Ba0.65_{0.65}Na0.35_{0.35}Fe2_2As2_2 point along the cc direction. Magnetic correlations in these materials cannot be considered as Ising like, and spin-orbit coupling must be included in a quantitative theory.Comment: 5 pages, 4 figure

    Interaction of the ionic liquid [BMP][TFSA] with rutile TiO2(110) and coadsorbed lithium

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    Aiming at a fundamental understanding of the processes at the electrode|ionic liquid interface in Li ion batteries, we investigated the interaction of the ionic liquid n-butyl-n-methylpyrrolidinium bis(trifluoromethylsulfonyl)imide [BMP][TFSA] and of Li with a reduced rutile TiO2(110) (1 × 1) surface as well as the interaction between [BMP][TFSA] and Li on the TiO2(110) surface under ultrahigh vacuum (UHV) conditions by X-ray photoelectron spectroscopy and scanning tunnelling microscopy. Between 80 K and 340 K [BMP][TFSA] adsorbs molecularly on the surface and at higher temperatures decomposition is observed, resulting in products such as Sad, Fad and TiNx. The decomposition pattern is compared to proposals based on theory. Small amounts of Li intercalate even at 80 K into TiO2(110), forming Li+ and Ti3+ species. The stoichiometry in the near surface region corresponds to Li7Ti5O12. For higher coverages in the range of several monolayers part of the Li remains on the surface, forming a Li2O cover layer. At 300 K, Ti3+ species become sufficiently mobile to diffuse into the bulk. Li post-deposition on a [BMP][TFSA] covered TiO2(110) surface at 80 K results in two competing reactions, Li intercalation and reaction with the IL, resulting in the decomposition of the IL. Upon warming up, the Ti3+ formed at low T is consumed by reaction with the IL adlayer and intermediate decomposition products. Post-deposition of [BMP][TFSA] (300 K) on a surface pre-covered with a Li2O/Li7Ti5O12 layer results in the partial reaction of [BMP][TFSA] with the Li+ and Ti3+ species, which gets completed at higher temperatures

    The effect of induced forelimb lameness on thoracolumbar kinematics during treadmill locomotion

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    Reasons for performing study: Lameness has often been suggested to result in altered movement of the back, but there are no detailed studies describing such a relationship in quantitative terms. Objectives: To quantify the effect of induced subtle forelimb lameness on thoracolumbar kinematics in the horse. Methods: Kinematics of 6 riding horses was measured at walk and at trot on a treadmill before and after the induction of reversible forelimb lameness grade 2 (AAEP scale 1-5). Ground reaction forces (GRF) for individual limbs were calculated from kinematics. Results: The horses significantly unloaded the painful limb by 11.5% at trot, while unloading at walk was not significant. The overall flexion-extension range of back motion decreased on average by 0.2° at walk and increased by 3.3° at trot (P<0.05). Changes in angular motion patterns of vertebral joints were noted only at trot, with an increase in flexion of 0.9° at T10 (i.e. angle between T6, T10 and T13) during the stance phase of the sound diagonal and an increase in extension of the thoracolumbar area during stance of the lame diagonal (0.7° at T13, 0.8° at T17, 0.5° at L1, 0.4° at L3 and 0.3° at L5) (P<0.05). Lameness further caused a lateral bending of the cranial thoracic vertebral column towards the lame side (1.3° at T10 and 0.9° at T13) (P<0.05) during stance of the lame diagonal. Conclusions: Both range of motion and vertebral angular motion patterns are affected by subtle forelimb lameness. At walk, the effect is minimal, at trot the horses increased the vertebral range of motion and changed the pattern of thoracolumbar motion in the sagittal and horizontal planes, presumably in an attempt to move the centre of gravity away from the lame side and reduce the force on the affected limb. Potential relevance: Subtle forelimb lameness affects thoracolumbar kinematics. Future studies should aim at elucidating whether the altered movement patterns lead to back and/or neck dysfunction in the case of chronic lameness

    A Combined XPS and Computational Study of the Chemical Reduction of BMP‐TFSI by Lithium

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    Employing density functional theory (DFT) calculations and X-ray photoelectron spectroscopy (XPS), we identify products of the reaction of the ionic liquid N,N-butylmethylpyrrolidinum bis(trifluoromethylsulfonyl)imide (BMP-TFSI) with lithium in order to model the initial chemical processes contributing to the formation of the solid electrolyte interphase in batteries. Besides lithium oxide, sulfide, carbide and fluoride, we find lithium cyanide or cyanamide as possible, thermodynamically stable product in the Li-poor regime, whilst Li3_{3}N is the stable product in the Li-rich regime. The thermodynamically controlled reaction products as well as larger fragments of TFSI persisting due to kinetic barriers could be identified by a comparison of experimentally and computationally determined core level binding energies

    Pneumatosis cystoides intestinalis of the ascending colon related to acarbose treatment: a case report

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    <p>Abstract</p> <p>Introduction</p> <p>Pneumatosis cystoides intestinalis is characterized by the presence of multiple gas-filled cysts in the intestinal wall, the submucosa and/or subserosa of the intestine. The term pneumatosis cystoides coli is synonymous with pneumatosis cystoides intestinalis when the disorder is limited to the colon. It is a secondary finding caused by a wide variety of underlying gastrointestinal or extragastrointestinal diseases but rarely occurs in the course of treatment with an α-glucosidase inhibitor. This is the first report of pneumatosis cystoides intestinalis after 12 years of treatment with the α-glucosidase inhibitor acarbose.</p> <p>Case presentation</p> <p>A 65-year-old Caucasian German woman was referred to our hospital for hemicolectomy. She had been treated for type 2 diabetes mellitus with an α-glucosidase inhibitor (acarbose, 150 mg daily) for 12 years. Three months before referral, she had complained of left abdominal pain. 'Polyposis coli' in the ascending colon and diverticulosis were diagnosed. Colonoscopy and computed tomography scans of the abdomen were repeated and revealed pneumatosis cystoides coli located in the ascending colon, whereas diverticulosis of the sigmoid colon was confirmed. Histological examination of a biopsy specimen only showed colon mucosa. After discontinuing administration of the α-glucosidase inhibitor for 3 months and on repeated colonoscopy, the polypoid lesions had completely disappeared.</p> <p>Conclusion</p> <p>This case illustrates that pneumatosis cystoides coli can be a source of diagnostic confusion. Pneumatosis cystoides coli must be considered in the initial differential diagnosis of patients especially in the presence of multiple colonic polypoid lesions. It is important to take pneumatosis cystoides intestinalis into consideration when prescribing α-glucosidase inhibitors to patients with diabetes who have diabetic autonomic neuropathy with decreased intestinal motility, or to patients taking steroids.</p

    Quantifying health effects of nutrition

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    Modelsimulaties geven aan dat met een grotere consumptie van fruit, groente en vis veel gezondheidswinst te behalen is. Dit soort schattingen kunnen worden gebruikt bij de onderbouwing van het voedingsbeleid. Met behulp van het Chronische-Ziekten-Model (CZM) van het RIVM kunnen de gezondheidseffecten op de langere termijn en zorggerelateerde kosten van beleidsdoelstellingen en voedingsinterventies worden doorgerekend. De modelsimulaties geven aan dat met een verhoging van de consumptie van groenten, fruit en vis relatief veel gezondheidswinst te behalen is. Ook blijkt dat ten aanzien van de vetzuursamenstelling de meeste gezondheidswinst inmiddels al is bereikt. Als de gehele Nederlandse bevolking de aanbevelingen voor gezonde voeding zou naleven, overlijden de komende twintig jaar naar schatting 140.000 minder mensen. De totale zorgkosten die anders in 20 jaar worden uitgegeven verminderen dan ongeveer met 3%. Doordat mensen langer leven zullen in de daaropvolgende jaren hun zorgkosten wel toenemen. Het model is ook gebruikt voor doorrekening van twee concrete voedingsinterventies, te weten SchoolGruiten en Werkfruit. Een kind dat deelneemt aan SchoolGruiten zal gemiddeld langer leven (+0,37 jaar) en ook langer gezond blijven. Er worden minder medische kosten op jongere leeftijd gemaakt. Deze kosten worden echter voor een groot deel uitgesteld. Voorwaarde voor de gunstige effecten is dat kinderen na de basisschool structureel meer groenten en fruit blijven eten. Werkfruit is een interventie die zich richt op de fruitconsumptie van werknemers in Nederland. Wanneer dit wordt ingevoerd bij 1 op de 10 werknemers, stijgt naar verwachting de levensverwachting van een 20-jarige met 0,08 jaar en nemen de gezondheidszorgkosten met 0,2 procent af.Simulations show that with an elevation of fruit, vegetable and fish consumption large health gains can be achieved. Model simulation is a good method to underpin nutritional policy. The RIVM Chronic Disease Model (CZM) can be used to calculate long term health effects and health care related costs of policy targets and dietary interventions. Simulations show that with an elevation of fruit, vegetable and fish consumption large health gains can be achieved. On the other hand, most health benefits related to fatty acids composition are already achieved. If the Dutch population complies with the dietary recommendations on nutrition, in 20 years, about 140,000 deaths and about 3% of the costs of health care will be saved. As the life expectancy increases people will experience health costs later in life. Two dietary interventions, 'SchoolGruiten' and 'Werkfruit' are simulated within CZM. Children participating in 'SchoolGruiten' will see their life expectancy increased (+0.37 year). They will also, on average, stay healthy for a longer time, assuming long term effects of the intervention. In this way such a child will make less medical costs at a younger age, however most of this costs are only postponed. Introducing 'Werkfruit' in the Netherlands onto one out of 10 employers, will increase the life expectancy of an 20-year old by an estimated 0.08 year and decrease the health-related costs of the whole population with 0.2 percent
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