Similarity of nuclear structure in 132Sn and 208Pb regions: proton-neutron multiplets

Starting from the striking similarity of proton-neutron multiplets in 134Sb and 210Bi, we perform a shell-model study of nuclei with two additional protons or neutrons to find out to what extent this analogy persists. We employ effective interactions derived from the CD-Bonn nucleon-nucleon potential renormalized by use of the V-low-k approach. The calculated results for 136Sb, 212Bi, 136I, and 212At are in very good agreement with the available experimental data. The similarity between 132Sn and 208Pb regions is discussed in connection with the effective interaction, emphasizing the role of core polarization effects.Comment: 4 pages, 3 figures, 2 table

Constraining dark energy fluctuations with supernova correlations

We investigate constraints on dark energy fluctuations using type Ia supernovae. If dark energy is not in the form of a cosmological constant, that is if the equation of state is not equal to -1, we expect not only temporal, but also spatial variations in the energy density. Such fluctuations would cause local variations in the universal expansion rate and directional dependences in the redshift-distance relation. We present a scheme for relating a power spectrum of dark energy fluctuations to an angular covariance function of standard candle magnitude fluctuations. The predictions for a phenomenological model of dark energy fluctuations are compared to observational data in the form of the measured angular covariance of Hubble diagram magnitude residuals for type Ia supernovae in the Union2 compilation. The observational result is consistent with zero dark energy fluctuations. However, due to the limitations in statistics, current data still allow for quite general dark energy fluctuations as long as they are in the linear regime.Comment: 18 pages, 6 figures, matches the published versio

Self-Consistent Nuclear Shell-Model Calculation Starting from a Realistic NN Potential

First self-consistent realistic shell-model calculation for the light p-shell nuclei is performed, starting from the high-precision nucleon-nucleon (NN) CD-Bonn potential. This realistic potential is renormalized deriving a low-momentum NN potential V-low-k that preserves exactly the two-nucleon low-energy physics. This V-low-k is suitable to derive a self-consistent Hartree-Fock basis that is employed to derive both effective single-particle energies and residual two-body matrix elements for the shell-model hamiltonian. Results obtained show the reliability of such a fundamental microscopic approach.Comment: 4 pages, 1 figure, 8 tables, to be published on Physics Letters

Generalized seniority scheme in light Sn isotopes

The yrast generalized seniority states are compared with the corresponding shell model states for the case of the Sn isotopes $^{104-112}$Sn. For most of the cases the energies agree within 100 keV and the overlaps of the wave functions are greater than 0.7.Comment: 8 pages, revtex. Submitted to Phys. Rev.

New limits on di-nucleons decay into invisible channels

Data of the radiochemical experiment [E.L.Fireman, 1978] with 1.7 t of KC_2H_3O_2, accumulated deep underground during ~1 yr, were reanalyzed to set limits on di-nucleons (nn and np) decays into invisible channels (disappearance, decay into neutrinos, etc.). The obtained lifetime bounds tau_np > 2.1 10^25 yr and tau_nn > 4.2 10^25 yr (at 90% C.L.) are better (or competitive) than those established in the recent experiments.Comment: 3 pages, accepted in JETP Letter

Robust high-dimensional precision matrix estimation

The dependency structure of multivariate data can be analyzed using the covariance matrix $\Sigma$. In many fields the precision matrix $\Sigma^{-1}$ is even more informative. As the sample covariance estimator is singular in high-dimensions, it cannot be used to obtain a precision matrix estimator. A popular high-dimensional estimator is the graphical lasso, but it lacks robustness. We consider the high-dimensional independent contamination model. Here, even a small percentage of contaminated cells in the data matrix may lead to a high percentage of contaminated rows. Downweighting entire observations, which is done by traditional robust procedures, would then results in a loss of information. In this paper, we formally prove that replacing the sample covariance matrix in the graphical lasso with an elementwise robust covariance matrix leads to an elementwise robust, sparse precision matrix estimator computable in high-dimensions. Examples of such elementwise robust covariance estimators are given. The final precision matrix estimator is positive definite, has a high breakdown point under elementwise contamination and can be computed fast

Evaluation of the clinical value of bone metabolic parameters for the screening of osseous metastases compared to bone scintigraphy

BACKGROUND: Bone metastases are common in many types of cancer. As screening methods different imaging modalities are available. A new approach for the screening of osseous metastases represents the measurement of bone metabolic markers. Therefore aim of this study was to evaluate the usefulness of the determination of bone metabolic markers aminoterminal propeptide of type I procollagen (PINP, osteoblastic activity) and the carboxyterminal pyridinoline cross-linked telopeptide of type I collagen (ICTP, osteoclastic activity) for the detection of bone metastases associated with other malignancies. METHODS: 88 patients aged 21 – 82 years with malignant tumors were prospectively studied. The serum concentrations of PINP and ICTP were measured and compared to the results of bone scintigraphy, radiological bone series, CT, MRI and clinical follow-up. RESULTS: Osseous metastases were found in 21 patients. 19 of them were correctly identified by bone scintigraphy (sensitivity: 90%). For bone metabolic markers results were as follows: ICTP sensitivity: 71%, specificity: 42%; PINP sensitivity: 24%, specificity: 96%. CONCLUSIONS: As markers of bone metabolism PINP and ICTP showed low sensitivity and/or specificity for the detection of osseous metastases. The presented markers did not seem to be sufficient enough to identify patients with bone metastases or to replace established screening methods

Identifying technical, physiological, tactical and psychological characteristics that contribute to career progression in soccer

This study sought to examine which technical, physiological, tactical and psychological characteristics at age 15 years contribute to successful soccer performance at age 19 years. Participants were male soccer players (n = 114; mean age 15.4±0.3 years), divided into elite and sub-elite groups based on their performance level at age 19 years. Technical, physiological, tactical and psychological characteristics were recorded when players were 15-year olds. Binary logistic regression analysis showed that performance level at age 19 was clearly associated with technical skills of passing and centering as well as agility and motivation levels recorded at age 15 years. These results extend our understanding of career progression in youth soccer and highlight the multidimensional nature of talent development processes in soccer. Moreover, it seems crucial that coaching support should be devoted to the development of passing and centering skills, agility and motivation in the development of youth players

Realistic Shell-Model Calculations for Proton-Rich N=50 Isotones

The structure of the N=50 isotones 98Cd, 97Ag, and 96Pd is studied in terms of shell model employing a realistic effective interaction derived from the Bonn-A nucleon-nucleon potential. The single-hole energies are fixed by resorting to an analysis of the low-energy spectra of the isotones with A>= 91. Comparison shows that our results are in very satisfactory agreement with the available experimental data. This supports confidence in the predictions of our calculationsComment: 8 pages, 3 figures, to be published on Journal of Physics

The Cosmic Microwave Background in an Inhomogeneous Universe - why void models of dark energy are only weakly constrained by the CMB

The dimming of Type Ia supernovae could be the result of Hubble-scale inhomogeneity in the matter and spatial curvature, rather than signaling the presence of a dark energy component. A key challenge for such models is to fit the detailed spectrum of the cosmic microwave background (CMB). We present a detailed discussion of the small-scale CMB in an inhomogeneous universe, focusing on spherically symmetric `void' models. We allow for the dynamical effects of radiation while analyzing the problem, in contrast to other work which inadvertently fine tunes its spatial profile. This is a surprisingly important effect and we reach substantially different conclusions. Models which are open at CMB distances fit the CMB power spectrum without fine tuning; these models also fit the supernovae and local Hubble rate data which favours a high expansion rate. Asymptotically flat models may fit the CMB, but require some extra assumptions. We argue that a full treatment of the radiation in these models is necessary if we are to understand the correct constraints from the CMB, as well as other observations which rely on it, such as spectral distortions of the black body spectrum, the kinematic Sunyaev-Zeldovich effect or the Baryon Acoustic Oscillations.Comment: 23 pages with 14 figures. v2 has considerably extended discussion and analysis, but the basic results are unchanged. v3 is the final versio