Baryon self energies in the chiral loop expansion

We compute the self energies of the baryon octet and decuplet states at the one-loop level applying the manifestly covariant chiral Lagrangian. It is demonstrated that expressions consistent with the expectation of power counting rules arise if the self energies are decomposed according to the Passarino-Veltman scheme supplemented by a minimal subtraction. This defines a partial summation of the chiral expansion. A finite renormalization required to install chiral power counting rules leads to the presence of an infrared renormalization scale. Good convergence properties for the chiral loop expansion of the baryon octet and decuplet masses are obtained for natural values of the infrared scale. A prediction for the strange-quark matrix element of the nucleon is made.Comment: 36 pages, 4 figures, 8 tables. The revised manuscript contains a proof that given any one-loop integral that arises when computing one-baryon processes it is sufficient to renormalize the scalar master-loop functions of the Passarino-Veltman reduction in a manner that the latter are compatible with the expectation of chiral counting rule

On the possibility of a discontinuous quark-mass dependence of baryon octet and decuplet masses

We compute the quark-mass dependence of the baryon octet and decuplet masses within the $\chi$-MS scheme at the one-loop level. The results are confronted with recent lattice QCD simulations of the MILC collaboration. A fair reproduction of the quark-mass dependence as suggested by the lattice simulations is obtained up to pion masses of about 700 MeV. Based on the chiral one-loop results we predict that the dependence of the baryon octet and decuplet masses on the quark-masses is discontinuous. Typically the pion-mass dependence is smooth up to about 300 MeV only. This is a consequence of self consistency imposed on the partial summation, i.e. the masses used in the loop functions are identical to those obtained from the baryon self energies. The 'mysterious' quark-mass dependence of the Xi mass predicted by the MILC collaboration is recovered in terms of a discontinuous chiral extrapolation.Comment: 12 pages, 1 figure, 1 table. 2nd version: corrected typos, clarified conclusions in the summary, results unchange

Unanticipated inflation and the value of the firm

Evidence presented here indicates that the relationship between stock returns and unexpected inflation differs systematically across firms. The differences are shown to be consistent with cross-sectional variation in firms' nominal contracts (monetary claims and depreciation tax shields). The differences are also partially explained by proxies for underlying firm characteristics that could create interaction between unexpected inflation and operating profitability. Finally, much if not most of the differences appear to arise because unexpected inflation is correlated with changes in expected aggregate real activity, the effects of which tend to vary across firms according to their systematic risk.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/26249/1/0000329.pd

CP-violation in K_{S,L}->\pi^{+}\pi^{-}\gamma and K_{S,L}->\pi^{+}\pi^{-}e^{+}e^{-} decays

The dependence of K_{S,L}->\pi^{+}\pi^{-}\gamma decay probabilities on photon polarization is calculated. The phases of terms of amplitude that arise from the pion-pion interaction are obtained by using a simple realistic model of pion-pion interaction via virtual \rho-meson, instead of the ChPT. The results are compared with those of other authors and the origin of slight discrepancies is explained. It is shown that the standard ChPT approach for K_{S,L}-> \pi^{+}\pi^{-}\gamma decays cannot reproduce the contribution of the \rho-meson to the P-wave \pi\pi interaction. The departure of the photon spectrum from pure bremsstrahlung due to the pion loop contribution to the direct emission amplitude is calculated. It is shown that the interference between the terms of amplitude with different CP-parity appears only when the photon is polarized (linearly or circularly). Instead of measuring the linear polarization, the angular correlation between the \pi^{+}\pi^{-} and e^{+}e^{-} planes in K_{S,L}->\pi^{+}\pi^{-}e^{+}e^{-} decay can be studied.Comment: 32 pages, 10 figures, 1 table, LaTex ; added figure, the comparison with ChPT revise

Lack of an Antibacterial Response Defect in Drosophila Toll-9 Mutant

Toll and Toll-like receptors represent families of receptors involved in mediating innate immunity response in insects and mammals. Although Drosophila proteome contains multiple Toll paralogs, Toll-1 is, so far, the only receptor to which an immune role has been attributed. In contrast, every single mammalian TLR is a key membrane receptor upstream of the vertebrate immune signaling cascades. The prevailing view is that TLR-mediated immunity is ancient. Structural analysis reveals that Drosophila Toll-9 is the most closely related to vertebrate TLRs and utilizes similar signaling components as Toll-1. This suggests that Toll-9 could be an ancestor of TLR-like receptors and could have immune function. Consistently, it has been reported that over-expression of Toll-9 in immune tissues is sufficient to induce the expression of some antimicrobial peptides in flies. These results have led to the idea that Toll-9 could be a constitutively active receptor that maintain significant levels of antimicrobial molecules and therefore provide constant basal protection against micro-organisms. To test theses hypotheses, we generated and analyzed phenotypes associated with a complete loss-of-function allele of Toll-9. Our results suggest that Toll-9 is neither required to maintain a basal anti-microbial response nor to mount an efficient immune response to bacterial infection

Unraveling hadron structure with generalized parton distributions

The generalized parton distributions, introduced nearly a decade ago, have emerged as a universal tool to describe hadrons in terms of quark and gluonic degrees of freedom. They combine the features of form factors, parton densities and distribution amplitudes--the functions used for a long time in studies of hadronic structure. Generalized parton distributions are analogous to the phase-space Wigner quasi-probability function of non-relativistic quantum mechanics which encodes full information on a quantum-mechanical system. We give an extensive review of main achievements in the development of this formalism. We discuss physical interpretation and basic properties of generalized parton distributions, their modeling and QCD evolution in the leading and next-to-leading orders. We describe how these functions enter a wide class of exclusive reactions, such as electro- and photo-production of photons, lepton pairs, or mesons. The theory of these processes requires and implies full control over diverse corrections and thus we outline the progress in handling higher-order and higher-twist effects. We catalogue corresponding results and present diverse techniques for their derivations. Subsequently, we address observables that are sensitive to different characteristics of the nucleon structure in terms of generalized parton distributions. The ultimate goal of the GPD approach is to provide a three-dimensional spatial picture of the nucleon, direct measurement of the quark orbital angular momentum, and various inter- and multi-parton correlations.Comment: 370 pages, 62 figures; Dedicated to Anatoly V. Efremov on occasion of his 70th anniversar

Genomic Relationships, Novel Loci, and Pleiotropic Mechanisms across Eight Psychiatric Disorders

Genetic influences on psychiatric disorders transcend diagnostic boundaries, suggesting substantial pleiotropy of contributing loci. However, the nature and mechanisms of these pleiotropic effects remain unclear. We performed analyses of 232,964 cases and 494,162 controls from genome-wide studies of anorexia nervosa, attention-deficit/hyper-activity disorder, autism spectrum disorder, bipolar disorder, major depression, obsessive-compulsive disorder, schizophrenia, and Tourette syndrome. Genetic correlation analyses revealed a meaningful structure within the eight disorders, identifying three groups of inter-related disorders. Meta-analysis across these eight disorders detected 109 loci associated with at least two psychiatric disorders, including 23 loci with pleiotropic effects on four or more disorders and 11 loci with antagonistic effects on multiple disorders. The pleiotropic loci are located within genes that show heightened expression in the brain throughout the lifespan, beginning prenatally in the second trimester, and play prominent roles in neurodevelopmental processes. These findings have important implications for psychiatric nosology, drug development, and risk prediction.Peer reviewe

Trends in birth rates in the United States since 1870 /

Thesis-Johns Hopkins University.Bibliographical footnotes