Multiparton Interactions in Photoproduction at HERA

The high energy photoproduction of jets is being observed at the ep collider, HERA. It may be that the HERA centre-of-mass energy is sufficiently large that the production of more than one pair of jets per ep collision becomes possible, owing to the large number density of the probed gluons. We construct a Monte Carlo model of such multiparton interactions and study their effects on a wide range of physical observables. The conclusion is that multiple interactions could have very significant effects upon the photoproduction final state and that this would for example make extractions of the gluon density in the photon rather difficult. Total rates for the production of many (i.e. > 2) jets could provide direct evidence for the presence of multiple interactions, although parton showering and hadronization significantly affect low transverse energy jets.Comment: 21 pages, 8 figures include

Engaging Diversity And Marginalization Through Participatory Action Research: A Model For Independent School Reform

Authored by a university researcher, school practitioner, and high school student, this article examines how independent schools can utilize participatory action research (PAR) to bolster diversity and inclusion efforts. A case study approach was taken to showcase a two-year PAR project at a progressive independent school that sought to: (a) enrich institutional knowledge of student diversity, (b) capture the present-day schooling experiences of historically marginalized students in independent school settings, and (c) develop a dynamic action plan to ameliorate school issues that emerged through the PAR inquiry process. Committed to institutional research that informs school policy and practice, we argue that PAR provides a rigorous, student-centered, and democratic model for independent school reform

Diffractive deeply inelastic scattering of hadronic states with small transverse size

Diffractive deeply inelastic scattering from a hadron is described in terms of diffractive quark and gluon distributions. If the transverse size of the hadronic state is sufficiently small, these distributions are calculable using perturbation theory. We present such a calculation and discuss the underlying dynamics. We comment on the relation between this dynamics and the pattern of scaling violation observed in the hard diffraction of large-size states at HERA.Comment: 8 pages including 3 figures, REVTE

Bounds on QCD Instantons from HERA

Signals for processes induced by QCD instantons are searched for in HERA data on the hadronic final state in deep-inelastic scattering. The maximally allowed fraction of instanton induced events is found at 95% confidence level to be on the percent level in the kinematic domain 0.0001<x<0.01 and 5 < Q-squared < 100 GeV-squared. The most stringent limits are obtained from the multiplicity distributions.Comment: 14 pages, latex, 9 figures as ps/ep

THREE ESSAYS ON CROSS-BORDER MERGERS AND ACQUISITIONS

This dissertation consists of three essays on cross-border mergers and acquisitions (M&As). The first essay studies horizontal and vertical investments between Organization for Economic Cooperation and Development (OECD) countries, while the second essay examines how investment patterns vary by country development. The third essay estimates the effect of merger policy reform on cross-border M&A activity in Europe. The first essay tests how well theories of horizontal and vertical foreign direct investment (FDI) explain observed patterns of cross-border M&As in OECD countries. Horizontal investment occurs when multinational firms produce in foreign countries to serve the foreign market, whereas vertical investment occurs when multinational firms source intermediate goods from foreign affiliates for final assembly and sales at home. The former is often used to displace exports when transport costs exceed local production costs, while the latter is often driven by cross-country factor price differentials. Little support is found for the traditional explanations of FDI as results indicate horizontal and vertical investments look much more similar than previously believed. The second essay challenges long-standing beliefs that the majority of FDI within the developed world is horizontal, whereas investments into developing nations are predominantly vertical. Developed-developed FDI is largely cross-border M&As and FDI into developing nations typically consists of greenfield investments. However, cross-border M&As are becoming more popular in developing countries and, contrary to previous beliefs, the proportion of horizontal and vertical investment is independent of country development. Results suggest trade costs have a stronger effect on developing countries, while no clear support is found for the idea that factor endowment drives vertical investments in developing nations. The third essay examines how reforms to European Commission Merger Regulation (ECMR) in 2004 affected cross-border M&A activity in Europe. The ECMR outlines competition rules and empowers the European Commission (EC) to block anti-competitive mergers adversely affecting the European market. Details of the reform suggest the law was expanded to cover more mergers, which is expected to have a non-positive effect on merger activity. Difference-in-differences results suggest the reform had no significant effect on cross-border merger activity in countries within the EC’s jurisdiction

Weak refinement in Z

An important aspect in the specification of distributed systems is the role of the internal (or unobservable) operation. Such operations are not part of the user interface (i.e. the user cannot invoke them), however, they are essential to our understanding and correct modelling of the system. Various conventions have been employed to model internal operations when specifying distributed systems in Z. If internal operations are distinguished in the specification notation, then refinement needs to deal with internal operations in appropriate ways. However, in the presence of internal operations, standard Z refinement leads to undesirable implementations. In this paper we present a generalization of Z refinement, called weak refinement, which treats internal operations differently from observable operations when refining a system. We illustrate some of the properties of weak refinement through a specification of a telecommunications protocol

Spiroplasma Diversity in Two Tabanid Flies and \u3cem\u3ein vivo\u3c/em\u3e Interactions of \u3cem\u3eSpiroplasma\u3c/em\u3e and \u3cem\u3eEntomoplasma\u3c/em\u3e

Chrysops vittatus, a small deer fly, and Tabanus atratus, a horse fly, were captured concurrently in Bulloch County, Georgia during June through September of 1989-1997 Cultures were made from adult females, and the frequency and diversity of spiroplasma carriage were determined by deformation and endpoint testing. Of the 90 Chrysops vittatus processed, 23 (25 .6%) carried spiroplasmas. The most prevalent spiroplasmas were representatives of group Vlll (20/23): strain B1357 (7/23); Spiroplasma syrphidicola (5/23); S. chrysopicola (4/23); strain TAAS-1 (4/23). Groups XVIII and XXXV were represented by S. Htorale (2/23) and strain B2649 (1/23), respectively. Of the 47 Tabanus atratus processed, 22 (46.8%) carried spiroplasmas. The most prevalent spiroplasma was represented by S. tabatudicola (12/22) of group XXXIII Other isolations were as follows: group XXIII, S. gladiatoris (3/22), group IV, strain PPS-1 (1/22); group XIV, S. corruscae (1/22); group XVIII, S. htorale (1/22); group XXXIII, strain TABS-2 (1/22); group XXXIV, strain B1901 (1/22), group XXXV, strain B2649 (1/22) Tabanus longiusculis and Tabanus hneola were live captured and randomly assigned to five treatment groups: A - spiroplasmas only; B - entomoplasmas only; C - spiroplasmas first and entomoplasmas later, D - entomoplasmas first and spiroplasmas later, E - control (sucrose only) Strain TN-1, Spiroplasma htorale, and strain ELCN-1, Entomoplasma ellychniae, were administered in 5% sugar water. Spiroplasma litorale was recovered from the following treatments: A - 12 of 12 gut cultures and 1 of 12 hemolymph cultures, C - 9 of 9 gut cultures and 1 of 9 hemolymph cultures; D - 7 of 7 gut cultures and 1 of 7 hemolymph cultures Entomoplasma ellychmae was recovered from the following treatments: C - 5 of 9 gut cultures and 1 of 9 hemolymph cultures, D - 7 of 7 gut cultures and 1 of 7 hemolymph cultures. To my knowledge, this is the first report of laboratory induced infections of A. litorale and E. ellychniae being administered in sugar water Also, the gut and hemolymph samples where both S. litorale and E. ellychniae were recovered represent the first reports of concurrent mollicute infections in tabanids

Affect and Informal Learning Through Adaptation of Workplace Practice

A study of the work of freelance creative practitioners exemplifies how adaptations to practice, forced by the pandemic, has produced significant informal learning, The paper reflects c on Epstein’s (this issue) four modes of ‘affect’ in the context of informal education, suggesting some different interpretations

Influence of Constraining Barrier on the 5th Lumbar and 1st Sacral joint Compressive Force during Manual Lifting

The purpose of this study was to examine the mechanical stresses on the lower back as the response of different heights of constraining barrier. Ten male subjects lifted a load from the floor to the knuckle height under the non-constrained and the constrained conditions with 4 different heights of constraining barrier (80%, 100%, 120% and 140% of knee height). The constrained condition was defined as the condition where a load was placed on the floor behind a certain level of bar. When lifting of the constrained conditions, subjects significantly increased the peak compressive forces at L5/S1 compared to the non-constrained (3868.8 ± 527.5 N, 4175.0 ± 486.0 N, 4162.4 ± 462.3 N, 4136.0 ± 553.1 N, 4079.4 ± 468.9 N for 0%, 80%, 100%, 120% and 140% barrier height conditions respectively). The subjects moved the load further from L5/S1 in the horizontal direction when lifting during the constrained conditions. While lifting during the constrained conditions subjects generated an increase in the sacral angle and a decrease of the knee flexion. The peak compressive forces at L5/S1 showed a statistically significant quadratic trend. However, the magnitude of the difference of peak compressive forces during the constrained conditions was small

Inelastic diffraction and color-singlet gluon-clusters in high-energy hadron-hadron and lepton-hadron collisions

It is proposed, that ``the colorless objects'' which manifest themselves in large-rapidity-gap events are color-singlet gluon-clusters due to self-organized criticality (SOC), and that optical-geometrical concepts and methods are useful in examing the space-time properties of such objects. A simple analytical expression for the $t$-dependence of the inelastic single diffractive cross section $d\sigma/dt$ ($t$ is the four-momentum transfer squared) is derived. Comparison with the existing data and predictions for future experiments are presented. The main differences and similarities between the SOC-approach and the ``Partons in the Pomeron (Pomeron and Reggeon)''-approach are discussed.Comment: 12 pages, 2 figure