Happy to help? A systematic review and meta-analysis of the effects of performing acts of kindness on the well-being of the actor

© 2018 The Authors. Do acts of kindness improve the well-being of the actor? Recent advances in the behavioural sciences have provided a number of explanations of human social, cooperative and altruistic behaviour. These theories predict that people will be ‘happy to help’ family, friends, community members, spouses, and even strangers under some conditions. Here we conduct a systematic review and meta-analysis of the experimental evidence that kindness interventions (for example, performing ‘random acts of kindness’) boost subjective well-being. Our initial search of the literature identified 489 articles; of which 24 (27 studies) met the inclusion criteria (total N = 4045). These 27 studies, some of which included multiple control conditions and dependent measures, yielded 52 effect sizes. Multi-level modeling revealed that the overall effect of kindness on the well-being of the actor is small-to-medium (δ = 0.28). The effect was not moderated by sex, age, type of participant, intervention, control condition or outcome measure. There was no indication of publication bias. We discuss the limitations of the current literature, and recommend that future research test more specific theories of kindness: taking kindness-specific individual differences into account; distinguishing between the effects of kindness to specific categories of people; and considering a wider range of proximal and distal outcomes. Such research will advance our understanding of the causes and consequences of kindness, and help practitioners to maximise the effectiveness of kindness interventions to improve well-being

Determination of the Form Factors for the Decay B0 --> D*-l+nu_l and of the CKM Matrix Element |Vcb|

We present a combined measurement of the Cabibbo-Kobayashi-Maskawa matrix element $|V_{cb}|$ and of the parameters $\rho^2$, $R_1$, and $R_2$, which fully characterize the form factors of the $B^0 \to D^{*-}\ell^{+}\nu_\ell$ decay in the framework of HQET, based on a sample of about 52,800 $B^0 \to D^{*-}\ell^{+}\nu_\ell$ decays recorded by the BABAR detector. The kinematical information of the fully reconstructed decay is used to extract the following values for the parameters (where the first errors are statistical and the second systematic): $\rho^2 = 1.156 \pm 0.094 \pm 0.028$, $R_1 = 1.329 \pm 0.131 \pm 0.044$, $R_2 = 0.859 \pm 0.077 \pm 0.022$, $\mathcal{F}(1)|V_{cb}| = (35.03 \pm 0.39 \pm 1.15) \times 10^{-3}$. By combining these measurements with the previous BABAR measurements of the form factors which employs a different technique on a partial sample of the data, we improve the statistical accuracy of the measurement, obtaining: $\rho^2 = 1.179 \pm 0.048 \pm 0.028, R_1 = 1.417 \pm 0.061 \pm 0.044, R_2 = 0.836 \pm 0.037 \pm 0.022,$ and $\mathcal{F}(1)|V_{cb}| = (34.68 \pm 0.32 \pm 1.15) \times 10^{-3}.$ Using the lattice calculations for the axial form factor $\mathcal{F}(1)$, we extract $|V_{cb}| =(37.74 \pm 0.35 \pm 1.25 \pm ^{1.23}_{1.44}) \times 10^{-3}$, where the third error is due to the uncertainty in $\mathcal{F}(1)$

Study of the Exclusive Initial-State Radiation Production of the DDˉD \bar D System

A study of exclusive production of the $D \bar D$ system through initial-state r adiation is performed in a search for charmonium states, where $D=D^0$ or $D^+$. The $D^0$ mesons are reconstructed in the $D^0 \to K^- \pi^+$, $D^0 \to K^- \pi^+ \pi^0$, and $D^0 \to K^- \pi^+ \pi^+ \pi^-$ decay modes. The $D^+$ is reconstructed through the $D^+ \to K^- \pi^+ \pi^+$ decay mode. The analysis makes use of an integrated luminosity of 288.5 fb$^{-1}$ collected by the BaBar experiment. The $D \bar D$ mass spectrum shows a clear $\psi(3770)$ signal. Further structures appear in the 3.9 and 4.1 GeV/$c^2$ regions. No evidence is found for Y(4260) decays to $D \bar D$, implying an up per limit \frac{\BR(Y(4260)\to D \bar D)}{\BR(Y(4260)\to J/\psi \pi^+ \pi^-)} < 7.6 (95 % confidence level)

Measurements of differential production cross sections for a Z boson in association with jets in pp collisions at root s=8 TeV

Peer reviewe

Measurements of Branching Fractions, Polarizations, and Direct CP-Violation Asymmetries in B→ρK∗ and B→f0(980)K∗ Decays

We report searches for B -meson decays to the charmless final states ρ K ∗ and f 0 ( 980 ) K ∗ with a sample of 232 × 10 6 B ¯¯¯ B pairs collected with the BABAR detector at the PEP-II e + e − collider. We measure in units of 10 − 6 the following branching fractions, where the first error quoted is statistical and the second systematic, or upper limits are given at the 90% confidence level : B ( B + → ρ 0 K * + ) < 6.1 , B ( B + → ρ + K * 0 ) = 9.6 ± 1.7 ± 1.5 , B ( B 0 → ρ − K * + ) < 12.0 , B ( B 0 → ρ 0 K * 0 ) = 5.6 ± 0.9 ± 1.3 , B ( B + → f 0 ( 980 ) K * + ) = 5.2 ± 1.2 ± 0.5 , and B ( B 0 → f 0 ( 980 ) K * 0 ) < 4.3 . For the significant modes, we also measure the fraction of longitudinal polarization and the charge asymmetry: f L ( B + → ρ + K * 0 ) = 0.52 ± 0.10 ± 0.04 , f L ( B 0 → ρ 0 K * 0 ) = 0.57 ± 0.09 ± 0.08 , A C P ( B + → ρ + K * 0 ) = − 0.01 ± 0.16 ± 0.02 , A C P ( B 0 → ρ 0 K * 0 ) = 0.09 ± 0.19 ± 0.02 , and A C P ( B + → f 0 ( 980 ) K * + ) = − 0.34 ± 0.21 ± 0.03

Factors Associated with Revision Surgery after Internal Fixation of Hip Fractures

Background: Femoral neck fractures are associated with high rates of revision surgery after management with internal fixation. Using data from the Fixation using Alternative Implants for the Treatment of Hip fractures (FAITH) trial evaluating methods of internal fixation in patients with femoral neck fractures, we investigated associations between baseline and surgical factors and the need for revision surgery to promote healing, relieve pain, treat infection or improve function over 24 months postsurgery. Additionally, we investigated factors associated with (1) hardware removal and (2) implant exchange from cancellous screws (CS) or sliding hip screw (SHS) to total hip arthroplasty, hemiarthroplasty, or another internal fixation device. Methods: We identified 15 potential factors a priori that may be associated with revision surgery, 7 with hardware removal, and 14 with implant exchange. We used multivariable Cox proportional hazards analyses in our investigation. Results: Factors associated with increased risk of revision surgery included: female sex, [hazard ratio (HR) 1.79, 95% confidence interval (CI) 1.25-2.50; P = 0.001], higher body mass index (fo