Learning influences host choice in tsetse

A learning capacity for feeding is described in many insect species including vectors of diseases, but has never been reported in tsetse flies (Diptera, Glossinidae), the cyclic vectors of human (sleeping sickness) and animal trypanosomoses in Africa. Repeated feeding on the same host species by a disease vector is likely to increase the within-species disease-transmission risk, but to decrease it between species

Recurrences of ventricular tachycardia after stereotactic arrhythmia radioablation arise outside the treated volume: analysis of the swiss cohort

BACKGROUND AND AIMS Stereotactic arrhythmia radioablation (STAR) has been recently introduced for the management of therapy-refractory ventricular tachycardia (VT). VT recurrences have been reported after STAR but the mechanisms remain largely unknown. We analyzed recurrences in our patients after STAR. METHODS From 09.2017 to 01.2020, 20 patients (68±8y, LVEF 37±15%) suffering from refractory VT were enrolled, 16/20 with a history of at least 1 electrical storm. Before STAR, an invasive electro-anatomical mapping (Carto3) of the VT substrate was performed. A mean dose of 23±2Gy was delivered to the planning target volume (PTV). RESULTS The median ablation volume was 26 ml (range 14-115) and involved the interventricular septum in 75% of patients. During the first 6 months after STAR, VT burden decreased by 92% (median value, from 108 to 10 VT/semester). After a median follow-up of 25 months, 12/20 (60%) developed a recurrence and underwent a redo ablation. VT recurrence was located in proximity of the treated substrate in 9 cases, remote from the PTV in 3 cases and involved a larger substrate over ≥3 LV segments in 2 cases. No recurrences occurred inside the PTV. Voltage measurements showed a significant decrease in both bipolar and unipolar signal amplitude after STAR. CONCLUSION STAR is a new tool available for the treatment of VT, allowing for a significant reduction of VT burden. VT recurrences are common during follow-up, but no recurrences were observed inside the PTV. Local efficacy was supported by a significant decrease in both bipolar and unipolar signal amplitude

Measurement of the quasi-elastic axial vector mass in neutrino-oxygen interactions

The weak nucleon axial-vector form factor for quasi-elastic interactions is determined using neutrino interaction data from the K2K Scintillating Fiber detector in the neutrino beam at KEK. More than 12,000 events are analyzed, of which half are charged-current quasi-elastic interactions nu-mu n to mu- p occurring primarily in oxygen nuclei. We use a relativistic Fermi gas model for oxygen and assume the form factor is approximately a dipole with one parameter, the axial vector mass M_A, and fit to the shape of the distribution of the square of the momentum transfer from the nucleon to the nucleus. Our best fit result for M_A = 1.20 \pm 0.12 GeV. Furthermore, this analysis includes updated vector form factors from recent electron scattering experiments and a discussion of the effects of the nucleon momentum on the shape of the fitted distributions.Comment: 14 pages, 10 figures, 6 table

Evidence for the η_b(1S) Meson in Radiative Υ(2S) Decay

We have performed a search for the η_b(1S) meson in the radiative decay of the Υ(2S) resonance using a sample of 91.6 × 10^6 Υ(2S) events recorded with the BABAR detector at the PEP-II B factory at the SLAC National Accelerator Laboratory. We observe a peak in the photon energy spectrum at E_γ = 609.3^(+4.6)_(-4.5)(stat)±1.9(syst) MeV, corresponding to an η_b(1S) mass of 9394.2^(+4.8)_(-4.9)(stat) ± 2.0(syst) MeV/c^2. The branching fraction for the decay Υ(2S) → γη_b(1S) is determined to be [3.9 ± 1.1(stat)^(+1.1)_(-0.9)(syst)] × 10^(-4). We find the ratio of branching fractions B[Υ(2S) → γη_b(1S)]/B[Υ(3S) → γη_b(1S)]= 0.82 ± 0.24(stat)^(+0.20)_(-0.19)(syst)

Restitution analysis of alternans and its relationship to arrhythmogenicity in hypokalaemic Langendorff-perfused murine hearts

Alternans and arrhythmogenicity were studied in hypokalaemic (3.0 mM K+) Langendorff-perfused murine hearts paced at high rates. Epicardial and endocardial monophasic action potentials were recorded and durations quantified at 90% repolarization. Alternans and arrhythmia occurred in hypokalaemic, but not normokalaemic (5.2 mM K+) hearts (P < 0.01): this was prevented by treatment with lidocaine (10 μM, P < 0.01). Fourier analysis then confirmed transition from monomorphic to polymorphic waveforms for the first time in the murine heart. Alternans and arrhythmia were associated with increases in the slopes of restitution curves, obtained for the first time in the murine heart, while the anti-arrhythmic effect of lidocaine was associated with decreased slopes. Thus, hypokalaemia significantly increased (P < 0.05) maximal gradients (from 0.55 ± 0.14 to 2.35 ± 0.67 in the epicardium and from 0.67 ± 0.13 to 1.87 ± 0.28 in the endocardium) and critical diastolic intervals (DIs) at which gradients equalled unity (from −2.14 ± 0.52 ms to 50.93 ± 14.45 ms in the epicardium and from 8.14 ± 1.49 ms to 44.64 ± 5 ms in the endocardium). While treatment of normokalaemic hearts with lidocaine had no significant effect (P > 0.05) on either maximal gradients (0.78 ± 0.27 in the epicardium and 0.83 ± 0.45 in the endocardium) or critical DIs (6.06 ± 2.10 ms and 7.04 ± 3.82 ms in the endocardium), treatment of hypokalaemic hearts with lidocaine reduced (P < 0.05) both these parameters (1.05 ± 0.30 in the epicardium and 0.89 ± 0.36 in the endocardium and 30.38 ± 8.88 ms in the epicardium and 31.65 ± 4.78 ms in the endocardium, respectively). We thus demonstrate that alternans contributes a dynamic component to arrhythmic substrate during hypokalaemia, that restitution may furnish an underlying mechanism and that these phenomena are abolished by lidocaine, both recapitulating and clarifying clinical findings

Search for B-meson decays to b_1ρ and b_1K^*

We present a search for decays of B mesons to final states with a b_1 meson and a ρ or K^*(892) meson. The search is based on a data sample consisting of 465 million BB̅ pairs collected by the BABAR detector at the SLAC National Accelerator Laboratory. We do not observe any statistically significant signal. The upper limits we set on the branching fractions range from 1.4 to 8.0×10^(-6) at the 90% confidence level, including systematic uncertainties

Measurement of D⁰-D̅⁰ mixing using the ratio of lifetimes for the decays D⁰→K⁻π⁺ and K⁺K⁻

We measure the rate of D^0-D̅ ^0 mixing with the observable y_(CP)=(τ_(Kπ)/τ_(KK))-1, where τ_(KK) and τ_(Kπ) are, respectively, the mean lifetimes of CP-even D^0→K^+K^- and CP-mixed D^0→K^-π^+ decays, using a data sample of 384  fb^(-1) collected by the BABAR detector at the SLAC PEP-II asymmetric-energy B Factory. From a sample of D^0 and D̅ ^0 decays where the initial flavor of the decaying meson is not determined, we obtain y_(CP)=[1.12±0.26(stat)±0.22(syst)]%, which excludes the no-mixing hypothesis at 3.3σ, including both statistical and systematic uncertainties. This result is in good agreement with a previous BABAR measurement of y_(CP) obtained from a sample of D^(*+)→D^0π^+ events, where the D^0 decays to K^-π^+, K^+K^-, and π^+π^-, which is disjoint with the untagged D^0 events used here. Combining the two results taking into account statistical and systematic uncertainties, where the systematic uncertainties are assumed to be 100% correlated, we find y_(CP)=[1.16±0.22(stat)±0.18(syst)]%, which excludes the no-mixing hypothesis at 4.1σ

Evidence for X(3872) → Ψ (2S)y in B^± → X(3872)K^± Decays and a Study of B → ccyK

In a search for B → ccyK decays with the BABAR detector, where cc includes J/Ψ and Ψ (2S), and K includes K^±, K^0_S , and K^*(892), we find evidence for X(3872) → J/Ψy and X(3872) → Ψ (2S) with 3:6σ and 3:5σ significance, respectively. We measure the product of branching fractions B(B^± → X(3872)K^±)B(X(3872) → J/Ψy)= [2:8 ± 0:8(stat) ± 0:1(syst)]X 10^(-6) and B(B^± → X(3872)K^±) X B(X(3872) → Ψ (2S)y) = [9:5 ± 2:7(stat) ± 0:6(syst)] X 10^(-6)

Measurement of D^0-D̅ ^0 Mixing from a Time-Dependent Amplitude Analysis of D^0→K^+π^-π^0 Decays

We present evidence of D^0-D̅ ^0 mixing using a time-dependent amplitude analysis of the decay D^0→K^+π^-π^0 in a data sample of 384  fb^(-1) collected with the BABAR detector at the PEP-II e^+e^- collider at the Stanford Linear Accelerator Center. Assuming CP conservation, we measure the mixing parameters x_(Kππ)^(0′)=[2.61_(-0.68)^(+0.57)(stat)±0.39(syst)]%, y_(Kππ)^(0′)=[-0.06_(-0.64)^(+0.55)(stat)±0.34(syst)]%. This result is inconsistent with the no-mixing hypothesis with a significance of 3.2 standard deviations. We find no evidence of CP violation in mixing