3,943 research outputs found
A lifecourse mendelian randomization study highlights the long-term influence of childhood body size on later life heart structure
Children with obesity typically have larger left ventricular heart dimensions during adulthood. However, whether this is due to a persistent effect of adiposity extending into adulthood is challenging to disentangle due to confounding factors throughout the lifecourse. We conducted a multivariable mendelian randomization (MR) study to separate the independent effects of childhood and adult body size on 4 magnetic resonance imaging (MRI) measures of heart structure and function in the UK Biobank (UKB) study. Strong evidence of a genetically predicted effect of childhood body size on all measures of adulthood heart structure was identified, which remained robust upon accounting for adult body size using a multivariable MR framework (e.g., left ventricular end-diastolic volume (LVEDV), Beta = 0.33, 95% confidence interval (CI) = 0.23 to 0.43, P = 4.6 Ă 10-10). Sensitivity analyses did not suggest that other lifecourse measures of body composition were responsible for these effects. Conversely, evidence of a genetically predicted effect of childhood body size on various other MRI-based measures, such as fat percentage in the liver (Beta = 0.14, 95% CI = 0.05 to 0.23, P = 0.002) and pancreas (Beta = 0.21, 95% CI = 0.10 to 0.33, P = 3.9 Ă 10-4), attenuated upon accounting for adult body size. Our findings suggest that childhood body size has a long-term (and potentially immutable) influence on heart structure in later life. In contrast, effects of childhood body size on other measures of adulthood organ size and fat percentage evaluated in this study are likely explained by the long-term consequence of remaining overweight throughout the lifecourse
APOE-Δ4 Shapes the Cerebral Organization in Cognitively Intact Individuals as Reflected by Structural Gray Matter Networks
Gray matter networks (GMn) provide essential information on the intrinsic organization of the brain and appear to be disrupted in Alzheimerâs disease (AD). Apolipoprotein E (APOE)-Δ4 represents the major genetic risk factor for AD, yet the association between APOE-Δ4 and GMn has remained unexplored. Here, we determine the impact of APOE-Δ4 on GMn in a large sample of cognitively unimpaired individuals, which was enriched for the genetic risk of AD. We used independent component analysis to retrieve sources of structural covariance and analyzed APOE group differences within and between networks. Analyses were repeated in a subsample of amyloid-negative subjects. Compared with noncarriers and heterozygotes, APOE-Δ4 homozygotes showed increased covariance in one network including primarily right-lateralized, parietal, inferior frontal, as well as inferior and middle temporal regions, which mirrored the formerly described AD-signature. This result was confirmed in a subsample of amyloid-negative individuals. APOE-Δ4 carriers showed reduced covariance between two networks encompassing frontal and temporal regions, which constitute preferential target of amyloid deposition. Our data indicate that, in asymptomatic individuals, APOE-Δ4 shapes the cerebral organization in a way that recapitulates focal morphometric alterations observed in AD patients, even in absence of amyloid pathology. This suggests that structural vulnerability in neuronal networks associated with APOE-Δ4 may be an early event in AD pathogenesis, possibly upstream of amyloid deposition
Time-dependent CP Asymmetries in Decays
We report the first measurement of CP-violation parameters in B^0 ->
K_S^0\rho^0\gamma decays based on 657 million B\bar B pairs collected with the
Belle detector at the KEKB asymmetric-energy collider. We measure the
time-dependent CP violating parameter S_{K_S^0\rho^0\gamma}= 0.11 +/-
0.33(stat.)^{+0.05}_{-0.09}(syst.). We also obtain the effective direct CP
violating parameter A_eff=0.05 +/- 0.18(stat.) +/- 0.06(syst.) for
m_{K_S\pi^+\pi^-}<1.8 GeV/c^2 and 0.6 GeV/c^2<m_{\pi^+\pi^-}<0.9 GeV/c^2.Comment: 6 pages, 3 figures, to be submitted to PR
Dalitz analysis of B --> K pi psi' decays and the Z(4430)+
From a Dalitz plot analysis of B --> K pi psi' decays, we find a signal for
Z(4430)+ --> pi+ psi' with a mass M= (4443(+15-12)(+19-13))MeV/c^2, width
Gamma= (107(+86-43)(+74-56))MeV, product branching fraction BR(B0 --> K-
Z(4430)+) x BR(Z(4430)+ --> pi+ psi')= (3.2(+1.8-0.9)(+5.3-1.6)) x 10^{-5}, and
significance of 6.4sigma that agrees with previous Belle measurements based on
the same data sample. In addition, we determine the branching fraction BR(B^0
--> K*(892)^0 psi')= (5.52(+0.35-0.32)(+0.53-0.58)) x 10^{-4} and the fraction
of K*(892)^0 mesons that are longitudinally polarized f_L=
44.8(+4.0-2.7)(+4.0-5.3)%. These results are obtained from a 605fb^{-1} data
sample that contains 657 million B-anti-B pairs collected near the Upsilon(4S)
resonance with the Belle detector at the KEKB asymmetric energy e+e- collider.Comment: Final version published in PRD(RC
Observation of Two Resonant Structures in e+e- to pi+ pi- psi(2S) via Initial State Radiation at Belle
The cross section for e+e- to pi+ pi- psi(2S) between threshold and
\sqrt{s}=5.5 GeV is measured using 673 fb^{-1} of data on and off the
\Upsilon(4S) resonance collected with the Belle detector at KEKB. Two resonant
structures are observed in the pi+ pi- psi(2S) invariant mass distribution, one
at 4361\pm 9\pm 9 MeV/c2 with a width of 74\pm 15\pm 10 MeV/c2, and another at
4664\pm 11\pm 5 MeV/c2 with a width of 48\pm 15\pm 3 MeV/c2, if the mass
spectrum is parameterized with the coherent sum of two Breit-Wigner functions.
These values do not match those of any of the known charmonium states.Comment: 10 pages, 5 figures, 2 tables, version to appear in Phys. Rev. Let
Measurements of Charmless Hadronic b->s Penguin Decays in the pi+pi-K+pi- Final State and First Observation of B0 -> rho0K+pi-
We report measurements of charmless hadronic B^0 decays into the pi+pi-K+pi+
final state. The analysis uses a sample of 657x10^6 BBbar pairs collected with
the Belle detector at the KEKB asymmetric-energy e+e- collider at the Y(4S)
resonance. The decay B^0 -> rho0 Kpi is observed for the first time; the
significance is 5.0sigma and the corresponding partial branching fraction for
M_Kpi in (0.75,1.20) GeV/c^2 is [2.8 +- 0.5(stat) +-0.5(syst)] x 10^{-6}. We
also obtain the first evidence for B^0 -> f0Kpi with 3.5sigma significance and
for B^0 -> pi+pi-K*0 with 4.5sigma significance. For the two-body decays B^0 ->
rho0K*0 and B^0 -> f0K*0, the significances are 2.7sigma and 2.5sigma,
respectively, and the upper limits on the branching fractions are 3.4x10^{-6}
and 2.2x10^{-6} at 90% confidence level.Comment: 6 pages, 3 figures. accepted by PRD(RC
Observation of Bs->Ds(*)+Ds(*)- using e+e- collisions and a determination of the Bs-Bsbar width difference \Delta\Gamma_s
We have made the first observation of Bs->Ds(*)+Ds(*)- decays using 23.6 fb-1
of data recorded by the Belle experiment running on the Upsilon(5S) resonance.
The branching fractions are measured to be B(B^0_s\ra D^+_s D^-_s) =
(1.0\,^{+0.4}_{-0.3}\,^{+0.3}_{-0.2})%, B(B^0_s\ra D^{*\pm}_s D^{\mp}_s) =
(2.8\,^{+0.8}_{-0.7}\,\pm 0.7)%, and B(B^0_s\ra D^{*+}_s D^{*-}_s) =
(3.1\,^{+1.2}_{-1.0}\,\pm 0.8)%; the sum is B(B^0_s\ra D^{(*)+}_s D^{(*)-}_s) =
(6.9\,^{+1.5}_{-1.3}\,\pm 1.9)%. Assuming Bs->Ds(*)+Ds(*)- saturates decays to
CP-even final states, the branching fraction determines the ratio
\Delta\Gamma_s/cos(\phi), where \Delta\Gamma_s is the difference in widths
between the two Bs-Bsbar mass eigenstates, and \phi is a CP-violating weak
phase. Taking CP violation to be negligibly small, we obtain
\Delta\Gamma_s/\Gamma_s =
0.147^{+0.036}_{-0.030}(stat.)^{+0.044}_{-0.042}(syst.), where \Gamma_s is the
mean decay width.Comment: 13 pages, 2 figures, 2 tables. v2: text added for clarification,
version published in Phys. Rev. Letter
Observation of B0 to p pbar K*0 with a large K*0 polarization
We observe the decay B0 to p pbar K*0 with a branching fraction of
(1.18^{+0.29}_{-0.25} (stat.) \pm 0.11 (syst.)) \times 10^{-6}. The statistical
significance is 7.2 sigma for the signal in the low ppbar mass region. We study
the decay dynamics of B0 to p pbar K*0 and compare it with B+ to p pbar K*+.
The K*0 meson is found to be almost 100% polarized (with a fraction of (101 \pm
13 \pm 3)% in the helicity zero state), while the K*+ meson has a (32 \pm 17
\pm 9)% fraction in the helicity zero state. The direct CP asymmetries for B0
to p pbar K*0 and B+ to p pbar K*+ are measured to be -0.08\pm 0.20\pm 0.02 and
-0.01\pm 0.19\pm 0.02, respectively. We also study the characteristics of the
low mass ppbar enhancements near threshold and the associated angular
distributions. In addition, we report improved measurements of the branching
fractions BF(B+ to p pbar K*+) = (3.38^{+0.73}_{-0.60} \pm 0.39) \times 10^{-6}
and BF(B0 to p pbar K0) = (2.51^{+0.35}_{-0.29} \pm 0.21) \times 10^{-6}, which
supersede our previous measurements. These results are obtained from a 492
fb^{-1} data sample collected near the Upsilon(4S) resonance with the Belle
detector at the KEKB asymmetric-energy e^+ e^- collider.Comment: 11 pages, 4 figures (8 figure files), submitted to Phys.Rev.Let
Study of the suppressed B meson decay B^- -> D K^-, D -> K^+ \pi^-
We report a study of the suppressed B meson decay B^- -> D K^- followed by D
-> K^+ \pi^-, where D indicates a D^0 or \bar{D}^0 state. The two decay paths
interfere and provide information on the CP-violating angle \phi_3. We use a
data sample containing 657 x 10^6 B\bar{B} pairs recorded at the \Upsilon(4S)
resonance with the Belle detector at the KEKB asymmetric-energy e^+e^- storage
ring. We do not find significant evidence for the mode B^- -> D K^-, D -> K^+
\pi^-, and set an upper limit of r_B < 0.19, where r_B is the magnitude of the
ratio of amplitudes |A(B^- -> \bar{D}^0 K^-)/A(B^- -> D^0 K^-)|. The decay B^-
-> D \pi^-, D -> K^+ \pi^- is also analyzed as a reference, for which we
observe a signal with 6.6\sigma significance, and measure the charge asymmetry
A_{D\pi} to be -0.02^{+0.15}_{-0.16}(stat) \pm 0.04(syst). In addition, the
ratio B(B^- -> D^0 K^-)/B(B^- -> D^0 \pi^-) is measured to be [6.77 \pm
0.23(stat) \pm 0.30(syst)] x 10^{-2}.Comment: 6 pages, 3 figures, 2 table
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