bluuebunny/crossref_metadata_2025_split huggingface dataset:
Constraining B in galaxy clusters from statistics of giant radio halos
Authors: Cassano R. , Brunetti G. , Setti G. 
Published: May 2006

AbstractThere are several possibilities to constrain the value of the magnetic field in the ICM, the most direct ones being the combination of inverse Compton and synchrotron observations, and the Faraday rotation measures. Here we discuss on the possibility to provide constraints on the magnetic field in the ICM from the analysis of the statistical properties of the giant radio halos, Mpc‐scale diffuse radio emission in galaxy clusters. Present observations of a few well studied radio halos can be interpreted under the hypothesis that the emitting relativistic electrons are re‐accelerated on their way out. By using statistical calculations carried out in the framework of the re‐acceleration model we show that the observed radiopower vs cluster mass correlation in radio halos can be reproduced only by assuming μG fields in the ICM and a scaling of the magnetic field with cluster mass B ∝ M b v, with b ≥ 0.6. We also show that the expected occurrence of radio halos with mass and redshift, and their number counts are sensitive to the magnetic field strength B in massive galaxy clusters and to the scaling of B with cluster mass. Thus future deep surveys of radio halos would provide constraints on B in galaxy clusters. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Diffuse radio sources in groups and poor clusters
Authors: Delain K. M. , Rudnick L. 
Published: May 2006

AbstractWe have discovered new diffuse radio sources likely associated with groups of galaxies at low redshift (0.01–0.04) and without apparent AGN by using the WENSS and WISH catalogs to perform an unbiased survey. These sources resemble the radio halos, mini‐halos, and ‘relics’ of rich clusters, which are thought to be powered by shocks and turbulence from infall into their deep potential wells. Our detection of similar sources within the shallow potential wells of groups of galaxies may challenge this model. Their radio luminosities are approximately two orders of magnitude higher than expected from the extrapolation of the apparent rich cluster radio/X‐ray luminosity relation. Even if these sources are misidentified distant clusters, they would lie above the apparent rich cluster radio/X‐ray luminosity relation in the literature, suggesting that detections of radio halos and relics thus far may be more biased than previously thought. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
New radio halos and relics in clusters of galaxies
Authors: Giovannini G. , Feretti L. , Govoni F. , Murgia M. , Pizzo R. 
Published: May 2006

AbstractWe present here new images of relics and halo sources in rich cluster of galaxies and the correlation between the halo radio surface brightness versus the cluster bolometric X‐ray luminosity. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Spectral index maps of radio halos and relics
Authors: Orrù E. , Feretti L. , Govoni F. , Murgia M. , Giovannini G. , Brunetti G. , Setti G. 
Published: May 2006

AbstractNew VLA observations at 90 cm are presented for the clusters of galaxies Abell 2219 and Abell 2744, which are characterized by the presence of a radio halo and relic. These sources are suggested to originate from particles reaccelerated in the cluster central regions, possibly by turbulence following major merger events. The study of the spectral properties of these sources is of great importance for the knowledge of the characteristics of relativistic particles and magnetic fields on large scales. Combining images at 90 and 20 cm, we obtained the spectral index distribution of the diffuse radio sources with a resolution of 1′.We produced radial brightness profiles at the two wavelengths, from which we calculated the radial spectral index trend. Our main result is that the spectral index shows a steepening with increasing distance from the cluster center to the edge. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Radio haloes in galaxy clusters: what do they tell us about the cluster's magnetic field?
Authors: Eilek J. , Owen F. , Marković T. 
Published: May 2006

AbstractOur new radio observations of a complete, X‐ray selected sample of clusters of galaxies suggest that diffuse radio haloes exist in all clusters, not just those undergoing a major merger. Some of our detected haloes are in clusters with strong cooling cores, which are thought to be dynamically relaxed. We infer that the plasma in every cluster contains relativistic particles and magnetic fields, whether or not the cluster has recently undergone a major merger. We do not know, however, what energizes the plasma in relaxed clusters. The answer could be mesoscale fluctuations in the underlying dark matter, or energy input from active galaxies, or a mixture of both. In addition, Faraday rotation from the plasma seems to require a magnetic field significantly stronger than that inferred from simple analyses of the radio haloes and/or hard X‐ray emission. We suspect this apparent problem comes from our incomplete understanding of magnetic structures and relativistic plasmas in the cluster; we suggest an alternative way to interpret radio and hard X‐ray data. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
The radio luminosity function of radio galaxies in distant clusters
Authors: Branchesi M. , Gioia I. M. , Fanti C. , Fanti R. , Perley R. 
Published: May 2006

AbstractA complete sample of 18 X‐ray selected clusters of galaxies belonging to the ROSAT North Ecliptic Pole (NEP) survey has been observed with the Very Large Array at 1.4 GHz. These are the most distant clusters in the X‐ray survey with redshift in the range 0.3 < z < 0.8. 79 radio sources are detected within half an Abell radius with an observed peak brightness ≥ 0.17 mJy beam–1. 32 out of the 79 sources are within 0.2 Abell radius, 22 of them are considered cluster members based on spectroscopic redshifts or their optical magnitude and morphological classification. The cluster radio galaxies are used to construct the radio luminosity function (RLF) of distant X‐ray selected clusters. A comparison with two nearby cluster RLFs shows that the NEP RLF lies above the local ones, has a steeper slope at low radio powers (≤ 1024 WHz–1) and shows no evidence for a break at ≈ 6 × 1024 WHz–1 which is observed in the nearby cluster RLFs. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Simulating large‐scale structure formation with magnetic fields
Authors: Dolag K. 
Published: May 2006

AbstractIn the past, different works based on numerical simulations have been presented to explain magnetic fields (MFs) in the large scale structure and within galaxy clusters. In this review, I will summarize the main findings obtained by different authors and – even if many details are still unclear – I will try to construct a consistent picture of our interpretation of largescale magnetic fields based on numerical effort. I will also sketch how this is related to our understanding of radio emission and summarize some arguments where our theoretical understanding has to be improved to match the observations. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
The origin and evolution of cluster magnetism
Authors: Shukurov A. , Subramanian K. , Haugen N. E. L. 
Published: May 2006

AbstractRandom motions can occur in the intergalactic gas of galaxy clusters at all stages of their evolution. Depending on the poorly known value of the Reynolds number, these motions can or cannot become turbulent, but in any case they can generate random magnetic fields via dynamo action. We argue that magnetic fields inferred observationally for the intracluster medium require dynamo action, and then estimate parameters of random flows and magnetic fields at various stages of the cluster evolution. Polarization in cluster radio halos predicted by the model would be detectable with the SKA. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
New mechanism of generation of large‐scale magnetic fields in merging protogalactic and protostellar clouds
Authors: Rogachevskii I. , Kleeorin N. , Chernin A. D. , Liverts E. 
Published: May 2006

AbstractA new mechanism of generation of large‐scale magnetic fields in colliding protogalactic clouds and merging protostellar clouds is discussed. Interaction of the colliding clouds produces large‐scale shear motions which are superimposed on small‐scale turbulence. Generation of the large‐scale magnetic field is due to a “shear‐current” effect (or “vorticity‐current” effect), and the mean vorticity is caused by the large‐scale shear motions of colliding clouds. This effect causes the generation of the mean magnetic field even in a nonrotating and nonhelical homogeneous turbulence. There is no quenching of the nonlinear shear‐current effect contrary to the quenching of the nonlinear alpha effect, the nonlinear turbulent magnetic diffusion, etc. During the nonlinear growth of the mean magnetic field, the shear‐current effect only changes its sign at some value of the mean magnetic field which determines the level of the saturated mean magnetic field. Numerical study shows that the saturated level of the mean magnetic field is of the order of the equipartition field determined by the turbulent kinetic energy. The estimated large‐scale magnetic field for merging protogalactic clouds is about several microgauss, and for merging protostellar clouds is of the order of several tenth of microgauss. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Divergence cleaning techniques in smoothed particle magnetohydrodynamics simulations
Authors: Ziegler E. , Dolag K. , Bartelmann M. 
Published: May 2006

AbstractSmoothed Particle Magnetohydrodynamics (SPMHD) algorithms are tested with a Brio & Wu shocktube in order to find a suitable algorithm for treating magnetic shocks in clusters of galaxies. In particular the treatment of a nonvanishing divergence of B is discussed because of its appearance due to numerical errors. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
The Japanese X‐ray missions
Authors: Fujita Y. 
Published: May 2006

AbstractHere, I briefiy introduce Japanese X‐ray missions: Suzaku and NeXT . Suzaku was launched on July 10, 2005. NeXT will be launched in 2011. They will open new windows into the workings of black holes, clusters of galaxies, active galaxies, and other very energetic objects. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Tissue engineering of vascular conduits
Authors: Yow K-H , Ingram J , Korossis S A , Ingham E , Homer-Vanniasinkam S 
Published: May 2006

AbstractBackgroundAutologous conduits are not available in up to 40 per cent of patients with arteriopathy who require coronary or lower limb revascularization, and access sites for renal dialysis may eventually become exhausted. Synthetic prostheses achieve a poor patency rate in small-calibre anastomoses. This review examines how vascular tissue engineering may be used to address these issues.MethodsA Medline search was performed, using the keywords ‘vascular tissue engineering’, ‘small diameter vascular conduit’, ‘vascular cell biology’, ‘biomechanics’, ‘cell seeding’ and ‘graft endothelialization’. Key references were hand-searched for relevant papers.Results and conclusionIn vitro and in vivo approaches are currently being used for guided cell repopulation of both biological and synthetic scaffolds. The major clinical problem has been extended culture time (approximately 6 weeks), which precludes their use in the acute setting. However, recent advances have led not only to improved patency rates for prostheses, but also to a potential reduction in culture time. In addition, increased mobilization of endothelial progenitor cells in the presence of ischaemic tissue may increase the autologous cell yield for scaffold reseeding with further reduction in culture time.
Population-based study of the diagnosis and treatment of gastrointestinal stromal tumours
Authors: Bümming P , Ahlman H , Andersson J , Meis-Kindblom J M , Kindblom L-G , Nilsson B 
Published: May 2006

AbstractBackgroundThe aim of this retrospective population-based study, which was conducted before the introduction of imatinib, was to evaluate the role of surgery in patients with gastrointestinal stromal tumours (GISTs) and clarify which subgroups might benefit from adjuvant treatment.MethodsTwo hundred and fifty-nine patients with clinically detected GISTs were studied. Univariate and multivariate analyses were performed to identify predictors for recurrent disease and survival.ResultsThirty of 48 patients with high-risk GISTs and all of those with overtly malignant tumours developed recurrent tumour after complete (R0) resection. Thirty-four of 38 first recurrences occurred within 36 months of surgery. No recurrence was observed after 72 months. R0 resection, achieved in 48 (80 per cent) of 60 patients with high-risk tumours, was significantly associated with a decreased risk of death from tumour recurrence (P = 0·008).ConclusionCompleteness of surgical resection is an independent prognostic factor in patients with high-risk GISTs. A period of adjuvant treatment with imatinib is recommended in patients with high-risk or overtly malignant GISTs who have undergone R0 resection and have a tumour-free interval of less than 6 years.
Systematic review of outcome of synchronous portal–superior mesenteric vein resection during pancreatectomy for cancer
Authors: Siriwardana H P P , Siriwardena A K 
Published: May 2006

AbstractBackgroundTumour clearance during pancreatectomy may be facilitated by resection of the portal–superior mesenteric vein, but this is associated with increased perioperative risk. There is no consensus about which patients benefit from portal–superior mesenteric vein resection.MethodsA systematic appraisal was carried out of the literature on portal–superior mesenteric vein resection during pancreatectomy to identify recurrent themes to guide management. A computerized search of the Medline and Embase databases found 52 non-duplicated studies providing relevant data in 1646 patients. Pooled data were examined for information on outcome categories relating to operation, complications, histopathology and overall outcome.ResultsThe median (range) number of patients with portal–superior mesenteric vein resection per cohort was 23 (4–172). Median operating time was 513 (168–1740) min and blood loss 1750 (300–26000) ml. Postoperative morbidity ranged from 9 to 78 per cent with a median per cohort of 42 per cent. There were 73 perioperative deaths (5·9 per cent of 1235 for whom mortality data were provided). Median survival was 13 months, and 1-, 3- and 5-year survival rates were 50, 16 and 7 per cent respectively. Specimen histopathology confirmed positive nodes in 67·4 per cent.ConclusionsThis is the largest collective report to date on portal–superior mesenteric vein resection in pancreatectomy. The high rate of nodal metastases and low 5-year survival rates suggest that by the time of tumour involvement of the portal vein cure is unlikely, even with radical resection.
Randomized clinical trial to evaluate the effects of perioperative supplemental oxygen administration on the colorectal anastomosis
Authors: García-Botello S A , García-Granero E , Lillo R , López-Mozos F , Millán M , Lledó S 
Published: May 2006

AbstractBackgroundPerioperative supplemental oxygen therapy may have beneficial effects on wound healing following colorectal surgery. The aim of this study was to evaluate the effects of such therapy on colorectal anastomotic pH and partial pressure of carbon dioxide (Pco2) gap.MethodsForty-five patients undergoing anterior resection for rectal or sigmoid cancer were randomized to receive 30 or 80 per cent perioperative oxygen. Administration was commenced after induction of anaesthesia and maintained for 6 h after surgery. Intragastric and anastomotic tonometric catheters were placed in each patient and intramucosal pH (pHi) was measured immediately after operation, and 6 and 24 h later. Gastric and anastomotic pHi and Pco2 gap in each group were compared.ResultsThere was a significantly lower anastomotic pHi and wider Pco2 gap for gastric readings in the 30 per cent O2 group, both 30 min (pHi, P = 0·006; Pco2 gap, P = 0·006) and 6 h (pHi, P = 0·024; Pco2 gap, P = 0·036) after surgery. There were no differences 24 h after surgery while breathing room air (pHi, P = 0·131; Pco2 gap P = 0·139). No difference was found between gastric and anastomotic readings at any time point in the 80 per cent O2 group.ConclusionPerioperative administration of 80 per cent O2 both during surgery and for 6 hours afterwards is associated with an improvement in relative anastomotic hypoperfusion as assessed by the measurement of pHi and Pco2 gap.
Meta-analysis of prophylactic antibiotic use in acute necrotizing pancreatitis
Authors: Mazaki T , Ishii Y , Takayama T 
Published: May 2006

AbstractBackgroundDeath from infected necrosis in acute pancreatitis is common and prevention has focused on prophylactic antibiotics. This study assesses whether intravenous prophylactic antibiotic use reduces infected necrosis and death in acute necrotizing pancreatitis.MethodsA meta-analysis of randomized controlled trials was carried out. Medline, Web of Science, the Cochrane controlled trials register and international conference proceedings were searched, with a citation review of relevant primary and review articles.ResultsSix of 328 studies assessed were included in data extraction. Primary outcome measures were infected necrosis and death. Secondary outcome measures were non-pancreatic infections, surgical intervention and length of hospital stay. Prophylactic antibiotic use was not associated with a statistically significant reduction in infected necrosis (relative risk (RR) 0·77 (95 per cent confidence interval (c.i.) 0·54 to 1·12); P = 0·173), mortality (RR 0·78 (95 per cent c.i. 0·44 to 1·39); P = 0·404), non-pancreatic infections (RR 0·71 (95 per cent c.i. 0·32 to 1·58); P = 0·402) and surgical intervention (RR 0·78 (95 per cent c.i. 0·55 to 1·11); P = 0·167). It was, however, associated with a statistically significant reduction in hospital stay (P = 0·040).ConclusionProphylactic antibiotics do not prevent infected necrosis or death in acute necrotizing pancreatitis.
Quantification of zolpidem in human plasma by high‐performance liquid chromatography with fluorescence detection
Authors: Nirogi Ramakrishna V. S. , Kandikere Vishwottam N. , Shrivasthava Wishu , Mudigonda Koteshwara 
Published: May 2006

AbstractA simple, reliable HPLC method with fluorescence detection (excitation 320 and emission 388 nm) was developed and validated for quantitation of zolpidem in human plasma. Following a single‐step liquid–liquid extraction, the analyte and internal standard (quinine) were separated using an isocratic mobile phase on a reversed‐phase C18 column. The lower limit of quantitation was 1.8 ng/mL, with a relative standard deviation of less than 5%. A linear dynamic range of 1.8–288 ng/mL was established. This HPLC method was validated with between‐batch and within‐batch precision of 1.7–4.8 and 1.2–2.3%, respectively. The between‐batch and within‐batch accuracy was 95.3–100.4 and 95.5–102.7%, respectively. Frequently coadministered drugs did not interfere with the described methodology. Stability of zolpidem in plasma was excellent, with no evidence of degradation during sample processing (autosampler) and 30 days storage in a freezer. This validated method is simple and repeatable enough to be used in pharmacokinetic studies. Copyright © 2006 John Wiley & Sons, Ltd.
Integrating hotel environmental strategies with management control: a structuration approach
Authors: Chung Lai Hong , Parker Lee D. 
Published: May 2006

AbstractThis study addresses the development of environmental strategies and associated management control in the international hotel industry, a sector of major economic and environmental impact hitherto largely neglected in the environmental management and accountability literature. The low key level of commitment to environmental management currently exhibited by the industry is considered in the context of dominant systems of hotel management performance evaluation and control, as well as the industry's current strategic management and budgetary practices. Informed by Giddens' structuration theory, the study offers a new theoretical framework, environmentally efficient resourcing, as a structured approach to the development of hotel environmental strategy and its management. Copyright © 2006 John Wiley & Sons, Ltd and ERP Environment.
Kidnapping: a criminal profile of persons convicted 1979–2001
Authors: Soothill Keith , Francis Brian , Ackerley Elizabeth 
Published: May 2006

AbstractKidnapping has been a neglected crime in criminological research. In fact, there has been a dramatic increase in the yearly numbers of police recorded kidnapping offences in England and Wales in the last 25 years, but this has not been matched by a similar increase in convictions. This study focuses on the official criminal histories of the 7042 males and 545 females who were convicted at least once for kidnapping between 1979 and 2001. Of these, 3.9% of the males and 2.6% of the females had convictions for kidnapping on more than one occasion.We examined two subgroups to ensure long observation periods for prior and subsequent convictions. Of those convicted of kidnapping in 2001, around one‐half (51.1%) of the males and around one‐third (36.6%) of the females hadpreviousconvictions. The previous convictions consist of a wide range of offences, with the most common being theft and violent offences. A 20‐year follow‐up of those convicted in 1979–81 showed that three in five males and one in three females are subsequently convicted on at least one more occasion for a standard‐list offence.An examination of convictions for other offences brought to court at the same time as the kidnap offence enabled a typology of kidnaps to be proposed. Those kidnaps with co‐convictions of an acquisitive nature declined over the period, whereas other types, including sexual and violent, showed rises. Changing shifts in the nature of kidnaps have important policy implications. Copyright © 2006 John Wiley & Sons, Ltd.