Colossal dielectric constants in transition-metal oxides

Many transition-metal oxides show very large ("colossal") magnitudes of the dielectric constant and thus have immense potential for applications in modern microelectronics and for the development of new capacitance-based energy-storage devices. In the present work, we thoroughly discuss the mechanisms that can lead to colossal values of the dielectric constant, especially emphasising effects generated by external and internal interfaces, including electronic phase separation. In addition, we provide a detailed overview and discussion of the dielectric properties of CaCu3Ti4O12 and related systems, which is today's most investigated material with colossal dielectric constant. Also a variety of further transition-metal oxides with large dielectric constants are treated in detail, among them the system La2-xSrxNiO4 where electronic phase separation may play a role in the generation of a colossal dielectric constant.Comment: 31 pages, 18 figures, submitted to Eur. Phys. J. for publication in the Special Topics volume "Cooperative Phenomena in Solids: Metal-Insulator Transitions and Ordering of Microscopic Degrees of Freedom

Production of Lambda and Sigma^0 hyperons in proton-proton collisions

This paper reports results on simultaneous measurements of the reaction channels pp -> pK+\Lambda and pp -> pK+\Sigma^0 at excess energies of 204, 239, and 284 MeV (\Lambda) and 127, 162, and 207 MeV (\Sigma^0). Total and differential cross sections are given for both reactions. It is concluded from the measured total cross sections that the high energy limit of the cross section ratio is almost reached at an excess energy of only about 200 MeV. From the differential distributions observed in the overall CMS as well as in the Jackson and helicity frames, a significant contribution of interfering nucleon resonances to the \Lambda production mechanism is concluded while resonant \Sigma^0-production seems to be of lesser importance and takes place only through specific partial waves of the entrance channel. The data also indicate that kaon exchange plays a minor role in the case of \Lambda- but an important role for \Sigma^0-production. Thus the peculiar energy dependence of the \Lambda-to-\Sigma^0 cross section ratio appears in a new light as its explanation requires more than mere differences between the p\Lambda and the p\Sigma^0 final state interaction. The data provide a benchmark for theoretical models already available or yet to come.Comment: 18 pages, 10 figures; accepted by The European Physical Journal A (EPJ A

Observation of the baryonic decay B \uaf 0 \u2192 \u39bc+ p \uaf K-K+

We report the observation of the baryonic decay B\uaf0\u2192\u39bc+p\uafK-K+ using a data sample of 471 7106 BB\uaf pairs produced in e+e- annihilations at s=10.58GeV. This data sample was recorded with the BABAR detector at the PEP-II storage ring at SLAC. We find B(B\uaf0\u2192\u39bc+p\uafK-K+)=(2.5\ub10.4(stat)\ub10.2(syst)\ub10.6B(\u39bc+)) 710-5, where the uncertainties are statistical, systematic, and due to the uncertainty of the \u39bc+\u2192pK-\u3c0+ branching fraction, respectively. The result has a significance corresponding to 5.0 standard deviations, including all uncertainties. For the resonant decay B\uaf0\u2192\u39bc+p\uaf\u3c6, we determine the upper limit B(B\uaf0\u2192\u39bc+p\uaf\u3c6)<1.2 710-5 at 90% confidence level

Search for Darkonium in e+e- Collisions

Collider searches for dark sectors, new particles interacting only feebly with ordinary matter, have largely focused on identifying signatures of new mediators, leaving much of dark sector structures unexplored. In particular, the existence of dark matter bound states (darkonia) remains to be investigated. This possibility could arise in a simple model in which a dark photon (A0 ) is light enough to generate an attractive force between dark fermions. We report herein a search for a JPC ¼ 1−− darkonium state, the ϒD, produced in the reaction eþe− → γϒD, ϒD → A0 A0 A0 , where the dark photons subsequently decay into pairs of leptons or pions, using 514 fb−1 of data collected with the BABAR detector. No significant signal is observed, and we set bounds on the γ − A0 kinetic mixing as a function of the dark sector coupling constant for 0.001 < mA0 < 3.16 GeV and 0.05 < mϒD < 9.5 GeV.publishedVersio

Risk profiles and one-year outcomes of patients with newly diagnosed atrial fibrillation in India: Insights from the GARFIELD-AF Registry.

BACKGROUND: The Global Anticoagulant Registry in the FIELD-Atrial Fibrillation (GARFIELD-AF) is an ongoing prospective noninterventional registry, which is providing important information on the baseline characteristics, treatment patterns, and 1-year outcomes in patients with newly diagnosed non-valvular atrial fibrillation (NVAF). This report describes data from Indian patients recruited in this registry. METHODS AND RESULTS: A total of 52,014 patients with newly diagnosed AF were enrolled globally; of these, 1388 patients were recruited from 26 sites within India (2012-2016). In India, the mean age was 65.8 years at diagnosis of NVAF. Hypertension was the most prevalent risk factor for AF, present in 68.5% of patients from India and in 76.3% of patients globally (P < 0.001). Diabetes and coronary artery disease (CAD) were prevalent in 36.2% and 28.1% of patients as compared with global prevalence of 22.2% and 21.6%, respectively (P < 0.001 for both). Antiplatelet therapy was the most common antithrombotic treatment in India. With increasing stroke risk, however, patients were more likely to receive oral anticoagulant therapy [mainly vitamin K antagonist (VKA)], but average international normalized ratio (INR) was lower among Indian patients [median INR value 1.6 (interquartile range {IQR}: 1.3-2.3) versus 2.3 (IQR 1.8-2.8) (P < 0.001)]. Compared with other countries, patients from India had markedly higher rates of all-cause mortality [7.68 per 100 person-years (95% confidence interval 6.32-9.35) vs 4.34 (4.16-4.53), P < 0.0001], while rates of stroke/systemic embolism and major bleeding were lower after 1 year of follow-up. CONCLUSION: Compared to previously published registries from India, the GARFIELD-AF registry describes clinical profiles and outcomes in Indian patients with AF of a different etiology. The registry data show that compared to the rest of the world, Indian AF patients are younger in age and have more diabetes and CAD. Patients with a higher stroke risk are more likely to receive anticoagulation therapy with VKA but are underdosed compared with the global average in the GARFIELD-AF. CLINICAL TRIAL REGISTRATION-URL: http://www.clinicaltrials.gov. Unique identifier: NCT01090362

First measurement of the polarization observable E in the p→(γ→,π⁺)n reaction up to 2.25 GeV

First results from the longitudinally polarized frozen-spin target (FROST) program are reported. The double-polarization observable E, for the reaction $\vec \gamma \vec p \to \pi^+n$, has been measured using a circularly polarized tagged-photon beam, with energies from 0.35 to 2.37 GeV. The final-state pions were detected with the CEBAF Large Acceptance Spectrometer in Hall B at the Thomas Jefferson National Accelerator Facility. These polarization data agree fairly well with previous partial-wave analyses at low photon energies. Over much of the covered energy range, however, significant deviations are observed, particularly in the high-energy region where high-L multipoles contribute. The data have been included in new multipole analyses resulting in updated nucleon resonance parameters. We report updated fits from the Bonn-Gatchina, J\"ulich, and SAID groups.Comment: 6 pages, 3 figure

ATHENA detector proposal — a totally hermetic electron nucleus apparatus proposed for IP6 at the Electron-Ion Collider

ATHENA has been designed as a general purpose detector capable of delivering the full scientific scope of the Electron-Ion Collider. Careful technology choices provide fine tracking and momentum resolution, high performance electromagnetic and hadronic calorimetry, hadron identification over a wide kinematic range, and near-complete hermeticity. This article describes the detector design and its expected performance in the most relevant physics channels. It includes an evaluation of detector technology choices, the technical challenges to realizing the detector and the R&amp;D required to meet those challenges

Decline in IGF1 in the bone marrow microenvironment initiates hematopoietic stem cell aging

Decline in hematopoietic stem cell (HSC) function with age underlies limited health span of our blood and immune systems. In order to preserve health into older age, it is necessary to understand the nature and timing of initiating events that cause HSC aging. By performing a cross-sectional study in mice, we discover that hallmarks of aging in HSCs and hematopoiesis begin to accumulate by middle age and that the bone marrow (BM) microenvironment at middle age induces and is indispensable for hematopoietic aging. Using unbiased approaches, we find that decreased levels of the longevity-associated molecule IGF1 in the local middle-aged BM microenvironment are a factor causing HSC aging. Direct stimulation of middle-aged HSCs with IGF1 rescues molecular and functional hallmarks of aging, including restored mitochondrial activity. Thus, although decline in IGF1 supports longevity, our work indicates that this also compromises HSC function and limits hematopoietic health span