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On the long-wave instability of natural-convection boundary layers
This paper considers the stability of the one-dimensional boundary
layer generated by
sudden heating of an infinite vertical wall. A quasi-steady approximation
is used to
analyse the asymptotic form of the lower branch of the neutral curve, corresponding
to disturbances of wavelength much greater than the boundary-layer width.
This leads
to predictions of the critical wavenumber for neutral stability and the
maximum
phase speed of the travelling waves. Results are obtained for a range of
Prandtl numbers and
are compared with solutions of the full stability equations and with numerical
simulations and experimental observations of cavity flows driven by sudden
heating of the sidewalls.</jats:p
Ferromagnetic Polarons in La0.5Ca0.5MnO3 and La0.33Ca0.67MnO3
Unrestricted Hartree-Fock calculations on La0.5Ca0.5MnO3 and La0.33Ca0.67MnO3
in the full magnetic unit cell show that the magnetic ground states of these
compounds consist of 'ferromagnetic molecules' or polarons ordered in
herring-bone patterns. Each polaron consists of either three or five Mn ions
separated by O- ions with a magnetic moment opposed to those of the Mn ions.
Ferromagnetic coupling within the polarons is strong while coupling between
them is relatively weak. Magnetic moments on the Mn ions range between 3.8 and
3.9 Bohr magnetons in La0.5Ca0.5MnO3 and moments on the O- ions are -0.7 Bohr
magnetons. Each polaron has a net magnetic moment of 7.0 Bohr magnetons, in
good agreement with recently reported magnetisation measurements from electron
microscopy. The polaronic nature of the electronic structure reported here is
obviously related to the Zener polaron model recently proposed for
Pr0.6Ca0.4MnO3 on the basis of neutron scattering data.Comment: 4 pages 5 figure
Limited susceptibility of three different mouse (Mus musculus) lines to Porcine circovirus-2 infection and associated lesions
Porcine circovirus associated disease (PCVAD), a major global problem for pork producers, is characterized microscopically by depletion and histiocytic replacement of follicles in the lymphoid tissues. The objectives of this study were to determine 1) if Porcine circovirus-2 (PCV-2) inoculated mice (Mus musculus) can develop PCV-2 associated lymphoid lesions and serve as a model for PCVAD, and 2) if differences in PCV-2 host susceptibility exist among mice lines. Three groups (n = 48/group) of 4-wk-old male mice were used: BALB/c, C57BL/6, and C3H/HeJ. A 2 Ă 2 factorial analysis was designed for each group using PCV-2 inoculation and keyhole limpet hemocyanin in incomplete Freundâs adjuvant injections on day 0 and 7 as factors. Necropsies were performed on days 12, 17, 22, 27, 32, and 37. Serum samples collected at each necropsy tested negative for anti-IgG PCV-2 antibodies in all mice at all time points by 2 different PCV-2 enzyme-linked immunosorbent assays (ELISA). The PCV-2 DNA was detected by polymerase chain reaction (PCR) in 93% (100/108) of tissues and 42.6% (46/108) of serum samples from PCV-2-inoculated mice from days 12 to 37. Microscopic lesions consistent with PCV-2 infection were not observed in any mice and PCV-2 DNA and PCV-2 antigen were not detected in tissues by in-situ-hybridization or immunohistochemistry assays, respectively. Based on incidence of PCV-2 DNA in serum samples, the C57BL/6 mouse line was more resistant to PCV-2 infection than the other lines. The results indicate the mouse model likely has limited utility to advance understanding of the pathogenesis of PCV-2 associated lesions, but mice could potentially be important in the epidemiology of PCV-2
Comparison of three enzyme-linked immunosorbent assays to detect Porcine circovirus-2 (PCV-2)-specific antibodies after vaccination or inoculation of pigs with distinct PCV-1 or PCV-2 isolates
Application of the 2008 definitions for invasive fungal diseases to the trial comparing voriconazole versus amphotericin B for therapy of invasive aspergillosis: a collaborative study of the Mycoses Study Group (MSG 05) and the European Organization for Research and Treatment of Cancer Infectious Diseases Group.
BACKGROUND: Strict definition of invasive aspergillosis (IA) cases is required to allow precise conclusions about the efficacy of antifungal therapy. The Global Comparative Aspergillus Study (GCAS) compared voriconazole to amphotericin B (AmB) deoxycholate for the primary therapy of IA. Because predefined definitions used for this trial were substantially different from the consensus definitions proposed by the European Organization for Research and Treatment of Cancer/Mycoses Study Group in 2008, we recategorized the 379 episodes of the GCAS according to the later definitions.
METHODS: The objectives were to assess the impact of the current definitions on the classification of the episodes and to provide comparative efficacy for probable/proven and possible IA in patients treated with either voriconazole or AmB. In addition to original data, we integrated the results of baseline galactomannan serum levels obtained from 249 (65.7%) frozen samples. The original response assessment was accepted unchanged.
RESULTS: Recategorization allowed 59 proven, 178 probable, and 106 possible IA cases to be identified. A higher favorable 12-week response rate was obtained with voriconazole (54.7%) than with AmB (29.9%) (P < .0001). Survival was higher for voriconazole for mycologically documented (probable/proven) IA (70.2%) than with AmB (54.9%) (P = .010). Higher response rates were obtained in possible IA treated with voriconazole vs AmB with the same magnitude of difference (26.2%; 95% confidence interval [CI], 7.2%-45.3%) as in mycologically documented episodes (24.3%; 95% CI, 11.9%-36.7%), suggesting that possible cases are true IA.
CONCLUSIONS: Recategorization resulted in a better identification of the episodes and confirmed the higher efficacy of voriconazole over AmB deoxycholate in mycologically documented IA
Endemic fungal infections in solid organ and hematopoietic cell transplant recipients enrolled in the TransplantâAssociated Infection Surveillance Network ( TRANSNET )
Background Invasive fungal infections are a major cause of morbidity and mortality among solid organ transplant ( SOT ) and hematopoietic cell transplant ( HCT ) recipients, but few data have been reported on the epidemiology of endemic fungal infections in these populations. Methods Fifteen institutions belonging to the TransplantâAssociated Infection Surveillance Network prospectively enrolled SOT and HCT recipients with histoplasmosis, blastomycosis, or coccidioidomycosis occurring between March 2001 and March 2006. Results A total of 70 patients (64 SOT recipients and 6 HCT recipients) had infection with an endemic mycosis, including 52 with histoplasmosis, 9 with blastomycosis, and 9 with coccidioidomycosis. The 12âmonth cumulative incidence rate among SOT recipients for histoplasmosis was 0.102%. Occurrence of infection was bimodal; 28 (40%) infections occurred in the first 6Â months post transplantation, and 24 (34%) occurred between 2 and 11Â years post transplantation. Three patients were documented to have acquired infection from the donor organ. Seven SOT recipients with histoplasmosis and 3 with coccidioidomycosis died (16%); no HCT recipient died. Conclusions This 5âyear multicenter prospective surveillance study found that endemic mycoses occur uncommonly in SOT and HCT recipients, and that the period at risk extends for years after transplantation.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/106980/1/tid12186.pd
Frame Theory for Signal Processing in Psychoacoustics
This review chapter aims to strengthen the link between frame theory and
signal processing tasks in psychoacoustics. On the one side, the basic concepts
of frame theory are presented and some proofs are provided to explain those
concepts in some detail. The goal is to reveal to hearing scientists how this
mathematical theory could be relevant for their research. In particular, we
focus on frame theory in a filter bank approach, which is probably the most
relevant view-point for audio signal processing. On the other side, basic
psychoacoustic concepts are presented to stimulate mathematicians to apply
their knowledge in this field
Search for VHE gamma rays from SS433/W50 with the CANGAROO-II telescope
SS433, located at the center of the supernova remnant W50, is a close
proximity binary system consisting of a compact star and a normal star. Jets of
material are directed outwards from the vicinity of the compact star
symmetrically to the east and west. Non-thermal hard X-ray emission is detected
from lobes lying on both sides. Shock accelerated electrons are expected to
generate sub-TeV gamma rays through the inverse-Compton process in the lobes.
Observations of the western X-ray lobe region of SS433/W50 system have been
performed to detect sub-TeV gamma-rays using the 10m CANGAROO-II telescope in
August and September, 2001, and July and September, 2002. The total observation
times are 85.2 hours for ON source, and 80.8 hours for OFF source data. No
significant excess of sub-TeV gamma rays has been found at 3 regions of the
western X-ray lobe of SS433/W50 system. We have derived 99% confidence level
upper limits to the fluxes of gamma rays and have set constraints on the
strengths of the magnetic fields assuming the synchrotron/inverse-Compton model
for the wide energy range of photon spectrum from radio to TeV. The derived
lower limits are 4.3 microgauss for the center of the brightest X-ray emission
region and 6.3 microgauss for the far end from SS433 in the western X-ray lobe.
In addition, we suggest that the spot-like X-ray emission may provide a major
contribution to the hardest X-ray spectrum in the lobe.Comment: 7 pages, 8 figures, to be published in Astroparticle Physic
Clogging transition of vibration-driven vehicles passing through constrictions
We report experimental results on the competitive passage of elongated self-propelled vehicles rushing through a constriction. For the chosen experimental conditions, we observe the emergence of intermittencies similar to those reported previously for active matter passing through narrow doors. Noteworthy, we find that, when the number of individuals crowding in front of the bottleneck increases, there is a transition from an unclogged to a clogged state characterized by a lack of convergence of the mean clog duration as the measuring time increases. It is demonstrated that this transition-which was reported previously only for externally vibrated systems such as colloids or granulars-appears also for self-propelled agents. This suggests that the transition should also occur for the flow through constrictions of living agents (e.g., humans and sheep), an issue that has been elusive so far in experiments due to safety risks
Search for a W' boson decaying to a bottom quark and a top quark in pp collisions at sqrt(s) = 7 TeV
Results are presented from a search for a W' boson using a dataset
corresponding to 5.0 inverse femtobarns of integrated luminosity collected
during 2011 by the CMS experiment at the LHC in pp collisions at sqrt(s)=7 TeV.
The W' boson is modeled as a heavy W boson, but different scenarios for the
couplings to fermions are considered, involving both left-handed and
right-handed chiral projections of the fermions, as well as an arbitrary
mixture of the two. The search is performed in the decay channel W' to t b,
leading to a final state signature with a single lepton (e, mu), missing
transverse energy, and jets, at least one of which is tagged as a b-jet. A W'
boson that couples to fermions with the same coupling constant as the W, but to
the right-handed rather than left-handed chiral projections, is excluded for
masses below 1.85 TeV at the 95% confidence level. For the first time using LHC
data, constraints on the W' gauge coupling for a set of left- and right-handed
coupling combinations have been placed. These results represent a significant
improvement over previously published limits.Comment: Submitted to Physics Letters B. Replaced with version publishe
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