Rapidity gap survival in the black-disk regime

We summarize how the approach to the black-disk regime (BDR) of strong interactions at TeV energies influences rapidity gap survival in exclusive hard diffraction pp -> p + H + p (H = dijet, Qbar-Q, Higgs). Employing a recently developed partonic description of such processes, we discuss (a) the suppression of diffraction at small impact parameters by soft spectator interactions in the BDR; (b) further suppression by inelastic interactions of hard spectator partons in the BDR; (c) correlations between hard and soft interactions. Hard spectator interactions substantially reduce the rapidity gap survival probability at LHC energies compared to previously reported estimates.Comment: 4 pages, 3 figures. Proceedings of XV International Workshop on Deep-Inelastic Scattering and Related Subjects (DIS 2007), Munich, Germany, Apr. 16-20, 200

Transverse imaging of the proton in exclusive diffractive pp scattering

In a recent paper (hep-ph/0608271) we describe a new approach to rapidity gap survival (RGS) in the production of high-mass systems (H = dijet, Higgs, etc.) in exclusive double-gap diffractive pp scattering, pp -> p + H + p. It is based on the idea that hard and soft interactions are approximately independent (QCD factorization), and allows us to calculate the RGS probability in a model-independent way in terms of the gluon generalized parton distributions (GPDs) in the colliding protons and the pp elastic scattering amplitude. Here we focus on the transverse momentum dependence of the cross section. By measuring the "diffraction pattern," one can perform detailed tests of the interplay of hard and soft interactions, and even extract information about the gluon GPD in the proton from the data.Comment: 4 pages, 2 figures, uses ws-procs9x6.cls. Proceedings of XIV International Workshop on Deep Inelastic Scattering (DIS2006), Tsukuba City, Japan, Apr 20 - 24, 200

Two Systems of Non-Symbolic Numerical Cognition

Studies of human adults, infants, and non-human animals demonstrate that non-symbolic numerical cognition is supported by at least two distinct cognitive systems: a “parallel individuation system” that encodes the numerical identity of individual items and an “approximate number system” that encodes the approximate numerical magnitude, or numerosity, of a set. The exact nature and role of these systems, however, have been debated for over a 100-years. Some argue that the non-symbolic representation of small numbers (<4) is carried out solely by the parallel individuation system and the non-symbolic representation of large numbers (>4) is carried out solely by the approximate number system. Others argue that all numbers are represented by the approximate number system. This debate has been fueled largely by some studies showing dissociations between small and large number processing and other studies showing similar processing of small and large numbers. Recent work has addressed this debate by showing that the two systems are present and distinct from early infancy, persist despite the acquisition of a symbolic number system, activate distinct cortical networks, and engage differentially based attentional constraints. Based on the recent discoveries, I provide a hypothesis that may explain the puzzling findings and makes testable predictions as to when each system will be engaged. In particular, when items are presented under conditions that allow selection of individuals, they will be represented as distinct mental items through parallel individuation and not as a numerical magnitude. In contrast, when items are presented outside attentional limits (e.g., too many, too close together, under high attentional load), they will be represented as a single mental numerical magnitude and not as distinct mental items. These predictions provide a basis on which researchers can further investigate the role of each system in the development of uniquely human numerical thought

Rejection Sensitivity and Social Support as Predictors of Peer Victimization among Youth with Psychiatric Illness

In this study, I examined whether rejection sensitivity and perceptions of social support predicted concurrent peer victimization in a sample of adolescents with psychiatric illness. Participants included 43 adolescents, aged 12-18 with diverse psychiatric diagnoses, who were recruited from a summer residential treatment program. Participants completed measures of peer victimization, perceptions of social support, and rejection sensitivity. Participants also completed the global victimization item in the Revised Olweus Bully/Victim Questionnaire, which allowed for comparison of rates of peer victimization across studies (Solberg & Olweus, 2003). Results replicate and extend previous research that indicates adolescents with psychiatric illness experience high rates of peer victimization (Cook, William, Guerra, & Kim, 2009; Hunt, Peters, & Rapee, 2012; Kärnä et al., 2011). Additionally, adolescents high in rejection sensitivity reported lower rates of peer victimization, and adolescents who perceive greater social support from parents, peers, and mentors evidenced lower peer victimization. Results do not support evidence of an interaction between perceptions of social support and rejection sensitivity. Taken together, the unique peer victimization experiences for youth with psychiatric illness have specific implications for researchers and practitioners

Personage And Post-adolescence In F. Scott Fitzgerald\u27s This Side of Paradise

This Side of Paradise, the semiautobiographical first novel of F. Scott Fitzgerald, provides insight into the developmental life stage of post-adolescence as it depicts protagonist Amory Blaine’s journey into adulthood. Early critical conversation regarding the novel focused largely on the inconsistencies in editing and form, and while such inconsistencies cannot be overlooked, the dismissive attitude of early critics curtailed any further structural approaches to the novel. To address this problem, I use an authorial critical scope to analyze the experimental, often improvisational, structure of the novel, which has typically been viewed by these critics as the work of a “clumsy” young writer. We then add the layer of Fitzgerald’s experience writing and publishing the novel to the structural and developmental approaches in order to enrich our understanding of postadolescence in the framework of This Side of Paradise. This layered conceptual approach often illuminates the inconsistencies in comparing previous scholarship against the yetunclear post-adolescent period. One of these inconsistencies, the issue of gender in the novel, continually presents itself in existing scholarship, even without the addition of post-adolescence. In Amory Blaine, Fitzgerald has created a new sort of male character, one which is influenced by and the mirror to the female characters of the novel. Fitzgerald, though unaware of it at the time, portrays the then-emerging American identity of the post-adolescent, doing this primarily through the use of paratextual elements and mixed literary genres, as well as an emphasis through the novel on developmental and generational identity

Advanced technology applications for second and third general coal gasification systems

The historical background of coal conversion is reviewed and the programmatic status (operational, construction, design, proposed) of coal gasification processes is tabulated for both commercial and demonstration projects as well as for large and small pilot plants. Both second and third generation processes typically operate at higher temperatures and pressures than first generation methods. Much of the equipment that has been tested has failed. The most difficult problems are in process control. The mechanics of three-phase flow are not fully understood. Companies participating in coal conversion projects are ordering duplicates of failure prone units. No real solutions to any of the significant problems in technology development have been developed in recent years

Determination of complex absorbing potentials from the electron self-energy

The electronic conductance of a molecule making contact to electrodes is determined by the coupling of discrete molecular states to the continuum electrode density of states. Interactions between bound states and continua can be modeled exactly by using the (energy-dependent) self-energy, or approximately by using a complex potential. We discuss the relation between the two approaches and give a prescription for using the self-energy to construct an energy-independent, non-local, complex potential. We apply our scheme to studying single-electron transmission in an atomic chain, obtaining excellent agreement with the exact result. Our approach allows us to treat electron-reservoir couplings independent of single electron energies, allowing for the definition of a one-body operator suitable for inclusion into correlated electron transport calculations.Comment: 11 pages, 8 figures; to be published in the J. Chem. Phy