Investment Rates and the Aggregate Production Function

In this paper we consider a simple version of the neoclassical growth model, and carry out an empirical analysis of the main determinants of aggregate investment across countries. More specifically, we study the effects on aggregate investment of income growth, capital income shares, the relative price of capital, and various market distortions. This exercise also sheds light into the shape of the neoclassical production function. We check these investment patterns for both OECD and non-OECD countries. We also decompose investment data into equipment and structures, and explore major factors affecting their relative pricesInvestment rates; Aggregate production function; Relative price of investment

Clinical scores for prediction of acute appendicitis in children in a hospital of Lima, Peru

Objective To determine the usefulness of the Alvarado score and the Pediatric Appendicitis score (PAS) in the Pediatric Emergency of the National Hospital Daniel A. Carrion.Materials and methods A prospective observational study was carried out of patients younger than 15 years of age with abdominal pain and suspected acute appendicitis (AA) attending the Pediatric Emergency in a Hospital of Lima, Peru. These patients underwent a survey to assess the parameters of the Alvarado score and PAS.Results Three hundred and seventeen patients with abdominal pain and suspected of AA were recruited over a study period of 12 months. Of the patients, 232 were considered to have AA clinically and underwent surgery. 85.3% were confirmed by pathology and 14.7% were normal. The mean Alvarado score was 8.27± 1.31; the mean Surgical Procedure Assessment (SPA) score was 8.08± 1.47. Sensitivity and specificity for both scores are equivalent. The area under the curve for the Alvarado score and SPA were 0.887 and 0.901, respectively. Alvarado score higher than 6 had a sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy of 88.9, 75.6, 97.4, 68.1, and 86.4%, respectively. SPA higher than 6 points had sensitivity, specificity, PPV, NPV, and accuracy of 84.3, 80.7, 94.7, 73.1, and 86.7%, respectively.Conclusion Alvarado score and the PAS are scores with high sensitivity, specificity, PPV, and accuracy for the diagnosis of AA when the score is higher than 6 points. The results found in our study justify their use in emergency services, but they should not be used as the only means of clinically determining the need for surgery.Keywords: acute appendicitis, children, prediction, score

Large NN Weinberg-Tomozawa interaction and spin-flavor symmetry

The construction of an extended version of the Weinberg-Tomozawa Lagrangian, in which baryons and mesons form spin-flavor multiplets, is reviewed and some of its properties discussed, for an arbitrary number of colors and flavors. The coefficient tables of spin-flavor irreducible representations related by crossing between the $s$-, $t$- and $u$-channels are explicitly constructed.Comment: 3 pages, no figures. Presented at the IVth International Conference on Quarks and Nuclear Physics, Madrid, June 5th-10th 200

Entangled spinning particles in charged and rotating black holes

Spin precession for an EPR pair of spin-1/2 particles in equatorial orbits around a Kerr-Newman black hole is studied. Hovering observers are introduced to ensure fixed reference frames in order to perform the Wigner rotation. These observers also guarantee a reliable direction to compare spin states in rotating black holes. The velocity of the particle due frame-dragging is explicitly incorporated by addition of velocities with respect the hovering observers and the corresponding spin precession angle is computed. The spin-singlet state is observed to be mixed with the spin-triplet by dynamical and gravity effects, thus it is found that a perfect anti-correlation of entangled states for these observers is deteriorated. Finally, an analysis concerning the different limit cases of parameters of spin precession including the frame-dragging effects is carried out.Comment: 25+1 pages, 7 eps figures. Major changes were made through all the manuscript. Clarifications regarding modifications were introduced through the draft. Figures were changed and reduced in number. arXiv admin note: text overlap with arXiv:quant-ph/030711

Institutional ownership, earnings management and earnings surprises: evidence from 39 years of U.S. data

Purpose: As the influence of institutional investors over managerial decision-making grows, so does the importance of understanding the effect of institutional investor ownership (IO) on firm outcomes. The authors take a comprehensive approach to studying the effect of IO on earnings management (EM). Design/methodology/approach: The authors study the relation between IO and EM using a sample of 59,503 listed U.S. firm-year observations from 1981–2019. The authors proxy EM with earnings surprises and with accrual-based and real activity measures. The authors test for nonlinear relations and analyze changes resulting from the passage of the Sarbanes–Oxley Act. Findings: The findings support a positive IO-EM relation overall, but show that the relation is dynamic and heavily context-dependent with evidence of nonlinearity. The authors also find evidence that IO positively affects accrual-based EM and real activities EM negatively. Originality/value: To the authors’ knowledge, this is the first study of the IO-EM relation to consider evidence of nonlinearity in the U.S. context, measuring changes to the relation over time, and with the use of several measures of EM

Meson-Baryon s-wave Resonances with Strangeness -3

Starting from a consistent SU(6) extension of the Weinberg-Tomozawa (WT) meson-baryon chiral Lagrangian (Phys. Rev. D74 (2006) 034025), we study the s-wave meson-baryon resonances in the strangeness S=-3 and negative parity sector. Those resonances are generated by solving the Bethe-Salpeter equation with the WT interaction used as kernel. The considered mesons are those of the 35-SU(6)-plet, which includes the pseudoscalar (PS) octet of pions and the vector (V) nonet of the rho meson. For baryons we consider the 56-SU(6)-plet, made of the 1/2+ octet of the nucleon and the 3/2+ decuplet of the Delta. Quantum numbers I(J^P)=0(3/2^-) are suggested for the experimental resonances Omega*(2250)- and Omega*(2380)-. Among other, resonances with I=1 are found, with minimal quark content sss\bar{l}l', being s the strange quark and l, l' any of the the light up or down quarks. A clear signal for such a pentaquark would be a baryonic resonance with strangeness -3 and electric charge of -2 or 0, in proton charge units. We suggest looking for K- Xi- resonances with masses around 2100 and 2240 MeV in the sector 1(1/2^-), and for pi Omega- and K- Xi*- resonances with masses around 2260 MeV in the sector 1(3/2^-).Comment: 3 pages, 1 Postscript figure, 7 table

Enhancing singlet oxygen generation by self-assembly of a porphyrin entrapped in supramolecular fibres

Singlet oxygen (SO) is one of the reactive oxygen species that is effective in various uses, including performing chemical reactions, treating water impurities, and aiding in medicinal therapy. The generation of SO is often efficient in solution, although generation from the solid phase in nanomaterials is less reliable. Here, we report the preparation of hybrid supramolecular materials that incorporate a photosensitizer within their nanostructured fibers and demonstrate their high efficiency in promoting SO formation. The incorporation of tetrakis(4-carboxyphenyl)porphyrin within the nanofibers of a bis-imidazolium gelator was proved by various techniques, including super-resolution radial fluctuations (SRRF) microscopy, which shows the location of the chromophore precisely. SO is generated from the dispersed nanofibers far more efficiently than the dissolved porphyrin; a 14-fold higher rate is observed initially. These results point to an effective approach to the generation of SO for several applications, from optimizing synthetic protocols to photomedicine