Permanent-magnet motors with rare-earth magnets are among the best candidates for high-performance applications such as automotive applications. However, due to their cost and risks relating to the ...security of supply, alternative solutions such as ferrite magnets have recently become popular. In this paper, the two major design challenges of using ferrite magnets for a high-torque-density and high-speed application, i.e., their low remanent flux density and low coercivity, are addressed. It is shown that a spoke-type design utilizing a distributed winding may overcome the torque density challenge due to a simultaneous flux concentration and a reluctance torque possibility. Furthermore, the demagnetization challenge can be overcome through the careful optimization of the rotor structure, with the inclusion of nonmagnetic voids on the top and bottom of the magnets. To meet the challenges of a high-speed operation, an extensive rotor structural analysis has been undertaken, during which electromagnetics and manufacturing tolerances are taken into account. Electromagnetic studies are validated through the testing of a prototype, which is custom built for static torque and demagnetization evaluation. The disclosed motor design surpasses the state-of-the-art performance and cost, merging the theories into a multidisciplinary product.
We present the development and validation of the Higgs Optimized b Identification Tagger (HOBIT), a multivariate b-jet identification algorithm optimized for Higgs boson searches at the CDF ...experiment at the Fermilab Tevatron. At collider experiments, b taggers allow one to distinguish particle jets containing B hadrons from other jets; these algorithms have been used for many years with great success at CDF. HOBIT has been designed specifically for use in searches for light Higgs bosons decaying via H→bb¯. This fact combined with the extent to which HOBIT synthesizes and extends the best ideas of previous taggers makes HOBIT unique among CDF b-tagging algorithms. Employing feed-forward neural network architectures, HOBIT provides an output value ranging from approximately −1 (“light-jet like”) to 1 (“b-jet like”); this continuous output value has been tuned to provide maximum sensitivity in light Higgs boson search analyses. When tuned to the equivalent light jet rejection rate, HOBIT tags 54% of b jets in Monte Carlo simulated Higgs boson events (mH=120GeV/c2) compared to 39% for SecVtx, the most commonly used b tagger at CDF. We present features of the tagger as well as its characterization in the form of b-jet finding efficiencies and false (light-jet) tag rates.
We present a series of patients with acute thoraco-lumbar fractures in whom we performed balloon vertebroplasty (kyphoplasty), either alone (percutaneous) or combined to posterior transpedicular ...fusion (open kyphoplasty). We emphasize the possibility of extending the use of kyphoplasty to non-osteoporotic vertebral fractures, and combining this method with traditional posterior fusion procedures.
Between 2003 and 2005, 138 patients suffering from thoraco-lumbar acute fractures, were treated in our Department. 87 corresponded to one vertebral level fractures; 34 to two levels, and the remaining 17 patients had more than two vertebrae affected. 65 patients (47%) received conservative therapy (rest in bed, physiotherapy, and subsequent progressive mobilization with cast). The remaining ones (73 cases; 43%) were treated invasively, performing balloon vertebroplasty alone (n=25), or kyphoplasty associated to posterior fusion in 15 cases (11%). Different kinds of screw posterior fusions were performed in the remaining patients (n=33; 24%). The latter group was not included in the present study. In the conservatively treated group (CTG), seven patients (11%) had a bad outcome, showing a persistency of hyperintensity in MRI-T2 sequences of the vertebral body, suggesting local edema. Mean hospitalization rate was 29 days in CTG. None of the 40 patients treated with kyphoplasty alone or combined with fusion showed abnormalities in neurological examination. They were classified in two groups: "Group a": Kyphoplasty alone (n=25). Mean of sagittal index in this group was 11 degrees (range: 6 degrees -15 degrees). In 9 patients, vertebral body collapse exceeded 25%. Mean hospitalization rate was 14 days. "Group b": Kyphoplasty and posterior fusion techniques (n=15): Mean sagittal index was 23 degrees (range: 13 degrees - 40 degrees). All the patients presented with a vertebral body collapse superior to 25%. All of them had posterior body wall involvement. This group was treated by surgery (decompression and fusion) and open vertebral body kyphoplasty. Mean hospitalization rate was 35 days. Clinical results of these 40 patients were measured by means of work status, restriction of physical activities and analgesic drug intake. Except for four patients of "Group b", 36 returned to their work. In 11 cases a slight reduction of physical activity was registered. Average "Group a" follow-up was 47 months (range: 10-72 months). A mean kyphosis correction of 5,3 degrees (sagittal index) was reached in this group. Average "Group b" follow-up was 26 months (range: 9-54). Mean kyphosis correction was 10,3 degrees . As for complications, we registered three balloon disruptions and five leakages into the disc.
Kyphoplasty could constitute an alternative and/or complementary treatment of traditional spinal stabilization-fusion procedures in non osteoporotic vertebral fractures. Therefore, it should be offered, when indicated, as a substantial possible part of the treatment, to the patients suffering from vertebral fractures. Additional advantages of combining kyphoplasty and posterior fusion are the possibility of reducing the number of fused levels (shorter instrumentations), and to perform a 360 degree stabilization-remodeling through a single posterior approach.
A
bstract
A search for the standard model Higgs boson produced in association with a top-quark pair
t
t
¯
H
is presented, using data samples corresponding to integrated luminosities of up to 5.1 fb
...−1
and 19.7 fb
−1
collected in pp collisions at center-of-mass energies of 7 TeV and 8 TeV respectively. The search is based on the following signatures of the Higgs boson decay: H → hadrons, H → photons, and H → leptons. The results are characterized by an observed
t
t
¯
H
signal strength relative to the standard model cross section,
μ
=
σ/σ
SM
,under the assumption that the Higgs boson decays as expected in the standard model. The best fit value is
μ
= 2.8 ± 1.0 for a Higgs boson mass of 125.6 GeV.
Abstract A search for new resonances decaying to WW, ZZ, or WZ is presented. Final states are considered in which one of the vector bosons decays leptonically and the other hadronically. Results are ...based on data corresponding to an integrated luminosity of 19.7 fb-1 recorded in proton-proton collisions at ... = 8 TeV with the CMS detector at the CERN LHC. Techniques aiming at identifying jet substructures are used to analyze signal events in which the hadronization products from the decay of highly boosted W or Z bosons are contained within a single reconstructed jet. Upper limits on the production of generic WW, ZZ, or WZ resonances are set as a function of the resonance mass and width. We increase the sensitivity of the analysis by statistically combining the results of this search with a complementary study of the all-hadronic final state. Upper limits at 95% confidence level are set on the bulk graviton production cross section in the range from 700 to 10 fb for resonance masses between 600 and 2500 GeV, respectively. These limits on the bulk graviton model are the most stringent to date in the diboson final state. Figure not available: see fulltext.
Abstract A search is reported for massive resonances decaying into a quark and a vector boson (W or Z), or two vector bosons (WW, WZ, or ZZ). The analysis is performed on an inclusive sample of ...multijet events corresponding to an integrated luminosity of 19.7 fb-1, collected in proton-proton collisions at a centre-of-mass energy of 8 TeV with the CMS detector at the LHC. The search uses novel jet-substructure identification techniques that provide sensitivity to the presence of highly boosted vector bosons decaying into a pair of quarks. Exclusion limits are set at a confidence level of 95% on the production of: (i) excited quark resonances q *decaying to qW and qZ for masses less than 3.2 TeV and 2.9 TeV, respectively, (ii) a Randall-Sundrum graviton GRS decaying into WW for masses below 1.2 TeV, and (iii) a heavy partner of the W boson W' decaying into WZ for masses less than 1.7 TeV. For the first time mass limits are set on W' arrow right WZ and GRS arrow right WW in the all-jets final state. The mass limits on q* arrow right qW, q* arrow right qZ, W' arrow right WZ, GRS arrow right WW are the most stringent to date. A model with a "bulk" graviton Gbulk that decays into WW or ZZ bosons is also studied. Figure not available: see fulltext.
(ProQuest: ... denotes formulae and/or non-USASCII text omitted; see image) Abstract Azimuthal dihadron correlations of charged particles have been measured in PbPb collisions at ...=2.76TeV by the ...CMS collaboration, using data from the 2011 LHC heavy-ion run. The data set includes a sample of ultra-central (0-0.2% centrality) PbPb events collected using a trigger based on total transverse energy in the hadron forward calorimeters and the total multiplicity of pixel clusters in the silicon pixel tracker. A total of about 1.8 million ultra-central events were recorded, corresponding to an integrated luminosity of 120 mub-1. The observed correlations in ultra-central PbPb events are expected to be particularly sensitive to initial-state fluctuations. The single-particle anisotropy Fourier harmonics, from v ^sub 2^ to v ^sub 6^, are extracted as a function of particle transverse momentum. At higher transverse momentum, the v ^sub 2^ harmonic becomes significantly smaller than the higher-order v ^sub n^ (ngreater than or equal to3). The p ^sub T^-averaged v ^sub 2^ and v ^sub 3^ are found to be equal within 2%, while higher-order v ^sub n^ decrease as n increases. The breakdown of factorization of dihadron correlations into single-particle azimuthal anisotropies is observed. This effect is found to be most prominent in the ultra-central PbPb collisions, where the initial-state fluctuations play a dominant role. A comparison of the factorization data to hydrodynamic predictions with event-by-event fluctuating initial conditions is also presented. Figure not available: see fulltext.
(ProQuest: ... denotes formulae and/or non-USASCII text omitted; see image) Abstract Measurements of the differential and double-differential Drell-Yan cross sections are presented using an ...integrated luminosity of 4.5 (4.8) fb^sup -1^ in the dimuon (dielectron) channel of proton-proton collision data recorded with the CMS detector at the LHC at ... = 7 TeV. The measured inclusive cross section in the Z-peak region (60-120 GeV) is sigma() = 986.4±0.6 (stat.)±5.9 (exp. syst.)±21.7 (th. syst.)±21.7 (lum.) pb for the combination of the dimuon and dielectron channels. Differential cross sections dsigma/dm for the dimuon, dielectron, and combined channels are measured in the mass range 15 to 1500 GeV and corrected to the full phase space. Results are also presented for the measurement of the double-differential cross section d^sup 2^sigma/dm d|y| in the dimuon channel over the mass range 20 to 1500 GeV and absolute dimuon rapidity from 0 to 2.4. These measurements are compared to the predictions of perturbative QCD calculations at next-to-leading and next-to-next-to-leading orders using various sets of parton distribution functions. Figure not available: see fulltext.
Bacterial DNA gyrases are type II topoisomerases made up of two A subunits and two B subunits. Coumarins are carbohydrate-containing antibiotics that inhibit topoisomerases II by competing with ATP ...for binding to the enzymes. High resistance to coumarins is produced in bacterial species by mutations in gyrB, the gene encoding subunit B. We have found an unusual mechanism of resistance to coumarins in Escherichia coli. This mechanism is exhibited by cells containing the wild-type gyrB, or its 5' half, in high copy number. Since homologous mutant gyrB (coumermycin resistant) truncated genes did not confer drug resistance at all under the same conditions, we propose that this mechanism of resistance is due to drug sequestration by the overproduced wild-type GyrB polypeptides. A corollary of this is that the amino half of GyrB is required and sufficient to fashion the ATP-binding domain of DNA gyrase, a conclusion that was further supported by mapping three independent coumarin-resistant mutations at Arg-136 of GyrB. Just upstream of this residue there is a glycine-rich sequence highly conserved in all topoisomerases II, which seems to be a good candidate for the actual ATP-binding site.
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