5,327 research outputs found
Event Shapes and Power Corrections in ep DIS
Deep-inelastic ep scattering data, taken with the H1 detector at HERA, are
used to study the event shape variables thrust, jet broadening, jet mass, C
parameter, and two kinds of differential two-jet rates over a large range of
``relevant energy'' Q between 7 GeV and 100 GeV. The Q dependence of the mean
values is fit to second order calculations of perturbative QCD applying power
law corrections proportional to 1/Q^p to account for hadronization effects. The
concept of these power corrections is tested by a systematic investigation in
terms of a non-perturbative parameter alpha_{p-1} and the strong coupling
constant.Comment: 3 pages, 1 table (latex, including npb.sty), 3 figures (eps), to be
published in the Proc. of the DIS99 Workshop, Berlin, 199
Anchoring a Lexicalized Tree-Adjoining Grammar for Discourse
We here explore a ``fully'' lexicalized Tree-Adjoining Grammar for discourse
that takes the basic elements of a (monologic) discourse to be not simply
clauses, but larger structures that are anchored on variously realized
discourse cues. This link with intra-sentential grammar suggests an account for
different patterns of discourse cues, while the different structures and
operations suggest three separate sources for elements of discourse meaning:
(1) a compositional semantics tied to the basic trees and operations; (2) a
presuppositional semantics carried by cue phrases that freely adjoin to trees;
and (3) general inference, that draws additional, defeasible conclusions that
flesh out what is conveyed compositionally.Comment: 7 pages, uses aclcol.st
QCD Scaling Violation at Small x
We investigate the evolution of parton densities at small values of the
momentum fraction, x, by including resummed anomalous dimensions in the
renormalization group equations. The resummation takes into account the
leading-logarithmic contributions (\alpha_S \ln x)^k given by the BFKL equation
and the next-to-leading-logarithmic corrections from quark evolution. We
present numerical results for the parton densities and the deep inelastic
structure function F_2.Comment: 8 pages, Latex, 3 uuencoded figure
Signatures of four-particle correlations associated with exciton-carrier interactions in coherent spectroscopy on bulk GaAs
Transient four-wave mixing studies of bulk GaAs under conditions of broad
bandwidth excitation of primarily interband transitions have enabled
four-particle correlations tied to degenerate (exciton-exciton) and
nondegenerate (exciton-carrier) interactions to be studied. Real
two-dimensional Fourier-transform spectroscopy (2DFTS) spectra reveal a complex
response at the heavy-hole exciton emission energy that varies with the
absorption energy, ranging from dispersive on the diagonal, through absorptive
for low-energy interband transitions to dispersive with the opposite sign for
interband transitions high above band gap. Simulations using a multilevel model
augmented by many-body effects provide excellent agreement with the 2DFTS
experiments and indicate that excitation-induced dephasing (EID) and
excitation-induced shift (EIS) affect degenerate and nondegenerate interactions
equivalently, with stronger exciton-carrier coupling relative to
exciton-exciton coupling by approximately an order of magnitude. These
simulations also indicate that EID effects are three times stronger than EIS in
contributing to the coherent response of the semiconductor
Plankton Ecology and Productivity in Jamaican Waters with New and Unique Applications
Unique applications of plankton ecology and productivity in Jamaican waters are presented. While traditional indices were inadequate descriptors of mangrove lagoon water quality, planktonic indices (total Chlorophyll a, zooplankton groups and species) were more reliable. Phytoplankton biomass was used to indicate a longitudinal gradient along the Hellshire Coastline, identifying non-point sources of enrichment, and movement of water masses in the absence of expensive Eulerian current meters. Along that same coast, mean primary production, determined by 14C techniques, confirmed a gradient from the eutrophic Kingston Harbour (21.1 g C m−2year−1) to the oligotrophic control site (0.52 g C m−2 year−1). Maximum inshore station values (36.75–18.39 g C m−2 year−1) were more than 20 times greater than offshore and exceeded Harbour values, confirming non-point sources and localized mechanisms as important inshore sources of eutrophication. The novel use of Ecopath with Ecosim (EwE) software to model trophic flows within planktonic communities was done in two bays. For Discovery Bay, on Jamaica’s north coast, the model indicated a developing ecosystem with open mineral cycles and poor nutrient conservation while in Foul and Folly Bays on the southeastern coast the model indicated greater resilience and ability to recover from perturbations. These applications have facilitated informed management decisions for sustainable use in Jamaican coastal ecosystems
The Impact of EU Unfair Contract Terms Law on U.S. Business-to-Consumer Internet Merchants
This article focuses on the application of European Union unfair contract terms law to retail Internet transactions that U.S. businesses might engage in with European consumers. It compares attitudes toward consumer protection regulation in the U.S. and the EU to provide some context within which the specific provisions of unfair contract terms law can be understood.
While many lawyers and legal academics in the U.S. who study the development of online markets are aware of the profound differences in U.S. and EU information privacy laws, the magnitude of the divergence in consumer electronic contracting law is not as widely recognized. The development of contract law on unfair terms in Europe over the last 25 years is an important change in EU contract law that has no direct counterpart in U.S. contract law.
The application of contract law on unfair terms to online transactions is not at all surprising to lawyers in the EU, but may come as quite a surprise to U.S. businesses and the lawyers who advise them if they have mistakenly assumed that cross-border variations in consumer contract law are not great. As some have learned to their detriment, it is not sufficient for businesses to simply deploy U.S. versions of their online terms and conditions in their European operations
Reconstructing particle masses from pairs of decay chains
A method is proposed for determining the masses of the new particles N,X,Y,Z
in collider events containing a pair of effectively identical decay chains Z to
Y+jet, Y to X+l_1, X to N+l_2, where l_1, l_2 are opposite-sign same-flavour
charged leptons and N is invisible. By first determining the upper edge of the
dilepton invariant mass spectrum, we reduce the problem to a curve for each
event in the 3-dimensional space of mass-squared differences. The region
through which most curves pass then determines the unknown masses. A
statistical approach is applied to take account of mismeasurement of jet and
missing momenta. The method is easily visualized and rather robust against
combinatorial ambiguities and finite detector resolution. It can be successful
even for small event samples, since it makes full use of the kinematical
information from every event.Comment: 12 pages, 5 figure
Myths about HIV and AIDS among serodiscordant couples in Malawi
Purpose: The paper reports on research that uncovered myths about HIV and AIDS held by
serodiscordant couples in Malawi, and the sources of these myths. The paper reflects on how
the myths affect serodiscordant couples’ engagement with HIV and AIDS information.
Design
Van Manen's (1997) approach to analysis of phenomenological data is used to analyse data from indepth
interviews conducted in Malawi with 21 serodiscordant couples and 3 individuals who had
separated from their partners because of serodiscordance.
Findings
Serodiscordant couples in Malawi believe and hold on to some inaccurate HIV and AIDS information
that can be seen as ‘myths’. Some of these myths are perpetuated by official HIV and AIDS information
when it is translated into the local languages. Other myths derive from social norms of the societies
where the couples live.
Practical implications: The findings of this paper have practical implications for how HIV and AIDS
information providers should engage with target audiences to understand the origins of the myths they
hold. The findings also imply that some myths have technical, religious, moral and cultural bases which
need to be addressed before challenging the myth itself.
Originality/Value: Using real-life descriptions of experiences of HIV and AIDS information provided by
serodiscordant couples, the authors reveal how myths can affect engagement with the information. The
authors make recommendations on how to address myths in ways that contribute to a positive
experience of HIV and AIDS information by serodiscordant couple
Myths about HIV and AIDS among serodiscordant couples in Malawi
Purpose: The paper reports on research that uncovered myths about HIV and AIDS held by
serodiscordant couples in Malawi, and the sources of these myths. The paper reflects on how
the myths affect serodiscordant couples’ engagement with HIV and AIDS information.
Design
Van Manen's (1997) approach to analysis of phenomenological data is used to analyse data from indepth
interviews conducted in Malawi with 21 serodiscordant couples and 3 individuals who had
separated from their partners because of serodiscordance.
Findings
Serodiscordant couples in Malawi believe and hold on to some inaccurate HIV and AIDS information
that can be seen as ‘myths’. Some of these myths are perpetuated by official HIV and AIDS information
when it is translated into the local languages. Other myths derive from social norms of the societies
where the couples live.
Practical implications: The findings of this paper have practical implications for how HIV and AIDS
information providers should engage with target audiences to understand the origins of the myths they
hold. The findings also imply that some myths have technical, religious, moral and cultural bases which
need to be addressed before challenging the myth itself.
Originality/Value: Using real-life descriptions of experiences of HIV and AIDS information provided by
serodiscordant couples, the authors reveal how myths can affect engagement with the information. The
authors make recommendations on how to address myths in ways that contribute to a positive
experience of HIV and AIDS information by serodiscordant couple
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