Impact of Power Allocation and Antenna Directivity in the Capacity of a Multiuser Cognitive Ad Hoc Network

This paper studies the benefits that power control and antenna directivity can bring to the capacity of a multiuser cognitive radio network. The main objective is to optimize the secondary network sum rate under the capacity constraint of the primary network. Exploiting location awareness, antenna directivity, and the power control capability, the cognitive radio ad hoc network can broaden its coverage and improve capacity. Computer simulations show that by employing the proposed method the system performance is significantly enhanced compared to conventional fixed power allocation

Effect of Location Accuracy and Shadowing on the Probability of Non-Interfering Concurrent Transmissions in Cognitive Ad Hoc Networks

Cognitive radio ad hoc systems can coexist with a primary network in a scanning-free region, which can be dimensioned by location awareness. This coexistence of networks improves system throughput and increases the efficiency of radio spectrum utilization. However, the location accuracy of real positioning systems affects the right dimensioning of the concurrent transmission region. Moreover, an ad hoc connection may not be able to coexist with the primary link due to the shadowing effect. In this paper we investigate the impact of location accuracy on the concurrent transmission probability and analyze the reliability of concurrent transmissions when shadowing is taken into account. A new analytical model is proposed, which allows to estimate the resulting secure region when the localization uncertainty range is known. Computer simulations show the dependency between the location accuracy and the performance of the proposed topology, as well as the reliability of the resulting secure region

Observation of a New Ξb- Resonance

From samples of p p collision data collected by the LHCb experiment at √ s = 7 , 8 and 13 TeV, corresponding to integrated luminosities of 1.0, 2.0 and 1.5     fb − 1 , respectively, a peak in both the Λ 0 b K − and Ξ 0 b π − invariant mass spectra is observed. In the quark model, radially and orbitally excited Ξ − b resonances with quark content b d s are expected. Referring to this peak as Ξ b ( 6227 ) − , the mass and natural width are measured to be m Ξ b ( 6227 ) − = 6226.9 ± 2.0 ± 0.3 ± 0.2     MeV / c 2 and Γ Ξ b ( 6227 ) − = 18.1 ± 5.4 ± 1.8     MeV / c 2 , where the first uncertainty is statistical, the second is systematic, and the third, on m Ξ b ( 6227 ) − , is due to the knowledge of the Λ 0 b baryon mass. Relative production rates of the Ξ b ( 6227 ) − → Λ 0 b K − and Ξ b ( 6227 ) − → Ξ 0 b π − decays are also reported

Preventing Left Ventricular Hypertrophy by ACE Inhibition in Hypertensive Patients With Type 2 Diabetes: A prespecified analysis of the Bergamo Nephrologic Diabetes Complications Trial (BENEDICT)

OBJECTIVE—In patients with type 2 diabetes, left ventricular hypertrophy (LVH) predicts cardiovascular events, and the prevention of LVH is cardioprotective. We sought to compare the effect of ACE versus non-ACE inhibitor therapy on incident electrocardiographic (ECG) evidence of LVH (ECG-LVH)

Evidence for the Rare Decay Σ+ →pμ+μ-

A search for the rare decay Σ + → p μ + μ − is performed using p p collision data recorded by the LHCb experiment at center-of-mass energies √ s = 7 and 8 TeV, corresponding to an integrated luminosity of 3     fb − 1 . An excess of events is observed with respect to the background expectation, with a signal significance of 4.1 standard deviations. No significant structure is observed in the dimuon invariant mass distribution, in contrast with a previous result from the HyperCP experiment. The measured Σ + → p μ + μ − branching fraction is ( 2.2 + 1.8 − 1.3 ) × 10 − 8 , where statistical and systematic uncertainties are included, which is consistent with the standard model prediction

Observation of D0 Meson Decays to π+π−μ+μ− and K+K−μ+μ− Final States

The first observation of the D0→π+π-μ+μ- and D0→K+K-μ+μ- decays is reported using a sample of proton-proton collisions collected by LHCb at a center-of-mass energy of 8 TeV, and corresponding to 2 fb-1 of integrated luminosity. The corresponding branching fractions are measured using as normalization the decay D0→K-π+[μ+μ-]ρ0/ω, where the two muons are consistent with coming from the decay of a ρ0 or ω meson. The results are B (D0→π+π-μ+μ- )=(9.64 ±0.48 ±0.51 ±0.97 )×10-7 and B (D0→K+K-μ+μ- )=(1.54 ±0.27 ±0.09 ±0.16 )×10-7 , where the uncertainties are statistical, systematic, and due to the limited knowledge of the normalization branching fraction. The dependence of the branching fraction on the dimuon mass is also investigated

Search for Baryon-Number Violating Ξ0b Oscillations

A search for baryon-number violating Ξ 0 b oscillations is performed with a sample of p p collision data recorded by the LHCb experiment, corresponding to an integrated luminosity of 3     fb − 1 . The baryon number at the moment of production is identified by requiring that the Ξ 0 b come from the decay of a resonance Ξ * − b → Ξ 0 b π − or Ξ ' − b → Ξ 0 b π − , and the baryon number at the moment of decay is identified from the final state using the decays Ξ 0 b → Ξ + c π − , Ξ + c → p K − π + . No evidence of baryon-number violation is found, and an upper limit at the 95% confidence level is set on the oscillation rate of ω < 0.08     ps − 1 , where ω is the associated angular frequency

Measurement of the Ratio of the B0→D*−τ+ντ and B0→D*−μ+νμ Branching Fractions Using Three-Prong τ-Lepton Decays

The ratio of branching fractions R ( D * − ) ≡ B ( B 0 → D * − τ + ν τ ) / B ( B 0 → D * − μ + ν μ ) is measured using a data sample of proton-proton collisions collected with the LHCb detector at center-of-mass energies of 7 and 8 TeV, corresponding to an integrated luminosity of 3     fb − 1 . For the first time, R ( D * − ) is determined using the τ -lepton decays with three charged pions in the final state. The B 0 → D * − τ + ν τ yield is normalized to that of the B 0 → D * − π + π − π + mode, providing a measurement of B ( B 0 → D * − τ + ν τ ) / B ( B 0 → D * − π + π − π + ) = 1.97 ± 0.13 ± 0.18 , where the first uncertainty is statistical and the second systematic. The value of B ( B 0 → D * − τ + ν τ ) = ( 1.42 ± 0.094 ± 0.129 ± 0.054 ) % is obtained, where the third uncertainty is due to the limited knowledge of the branching fraction of the normalization mode. Using the well-measured branching fraction of the B 0 → D * − μ + ν μ decay, a value of R ( D * − ) = 0.291 ± 0.019 ± 0.026 ± 0.013 is established, where the third uncertainty is due to the limited knowledge of the branching fractions of the normalization and B 0 → D * − μ + ν μ modes. This measurement is in agreement with the standard model prediction and with previous results

Measurements of CP asymmetries in charmless four-body Λb0 and Ξb0 decays

A search for C\!P violation in charmless four-body decays of {\varLambda } ^0_{b} and {\varXi } ^0_{b} baryons with a proton and three charged mesons in the final state is performed. To cancel out production and detection charge-asymmetry effects, the search is carried out by measuring the difference between the C\!P asymmetries in a charmless decay and in a decay with an intermediate charmed baryon with the same particles in the final state. The data sample used was recorded in 2011 and 2012 with the LHCb detector and corresponds to an integrated luminosity of 3 \text { fb} ^{-1} . A total of 18 C\!P asymmetries are considered, either accounting for the full phase space of the decays or exploring specific regions of the decay kinematics. No significant C\!P-violation effect is observed in any of the measurements

Amplitude Analysis of the Decay B 0 → KS0 π+π- and First Observation of the CP Asymmetry in B 0 →k∗ (892)-π+

The time-integrated untagged Dalitz plot of the three-body hadronic charmless decay ¯ B 0 → K 0 S π + π − is studied using a p p collision data sample recorded with the LHCb detector, corresponding to an integrated luminosity of 3.0     fb − 1 . The decay amplitude is described with an isobar model. Relative contributions of the isobar amplitudes to the ¯ B 0 → K 0 S π + π − decay branching fraction and C P asymmetries of the flavor-specific amplitudes are measured. The C P asymmetry between the conjugate ¯ B 0 → K ∗ ( 892 ) − π + and B 0 → K ∗ ( 892 ) + π − decay rates is determined to be − 0.308 ± 0.062