DIPSI: a Monte Carlo generator for elastic vector meson production in charged lepton-proton scattering

We present a Monte Carlo generator for exclusive vector meson production in charged lepton-proton interactions, l+p --> l+p+V, based on a QCD leading logarithm model calculation according to which the cross section for this process is proportional to the square of the gluon momentum density in the proton. The generator can be used for both fixed target and collider kinematics. Each event is assigned a weight equal to its cross section, so that the independent variables can be generated according to convenient distributions, not necessarily identical to the physics ones.Comment: 24 pages, 7 figures, Latex, to be published in Computer Physics Communication

Observation of Scaling Violations in Scaled Momentum Distributions at HERA

Charged particle production has been measured in deep inelastic scattering (DIS) events over a large range of $x$ and $Q^2$ using the ZEUS detector. The evolution of the scaled momentum, $x_p$, with $Q^2,$ in the range 10 to 1280 $GeV^2$, has been investigated in the current fragmentation region of the Breit frame. The results show clear evidence, in a single experiment, for scaling violations in scaled momenta as a function of $Q^2$.Comment: 21 pages including 4 figures, to be published in Physics Letters B. Two references adde

Higher-order interactions in fitness landscapes are sparse

Biological fitness arises from interactions between molecules, genes, and organisms. To discover the causative mechanisms of this complexity, we must differentiate the significant interactions from a large number of possibilities. Epistasis is the standard way to identify interactions in fitness landscapes. However, this intuitive approach breaks down in higher dimensions for example because the sign of epistasis takes on an arbitrary meaning, and the false discovery rate becomes high. These limitations make it difficult to evaluate the role of epistasis in higher dimensions. Here we develop epistatic filtrations, a dimensionally-normalized approach to define fitness landscape topography for higher dimensional spaces. We apply the method to higher-dimensional datasets from genetics and the gut microbiome. This reveals a sparse higher-order structure that often arises from lower-order. Despite sparsity, these higher-order effects carry significant effects on biological fitness and are consequential for ecology and evolution.Comment: 71 pages, various figure

Hard Exclusive Electroproduction of Two Pions off Proton and Deuteron at HERMES

Exclusive electroproduction of $\pi^+\pi^-$ pairs off hydrogen and deuterium targets has been studied with the HERMES experiment. The angular distribution of the $\pi^+$ in the $\pi^+\pi^-$ rest system has been studied in the invariant mass range $0.3 < m_{\pi\pi} <1.5$ GeV. Theoretical models derived in the framework of the Generalized Parton Distributions show that this angular distribution receives only contributions from the interference between the isoscalar channel I=0 and the isovector channel I=1.Comment: 5 pages, LaTex, 9 EPS figures. Talk given by R.Fabbri at SPIN 2002, BNL. References modifie

The Maluridae: Inferring Avian Biology and Evolutionary History from DNA Sequences

The Australo-Papuan fairy-wrens, emu-wrens and grasswrens comprise the passerine family Maluridae. They have long been known for their spectacular plumages, remarkable behavioural ecology and intriguing biogeography. The family has provided an ideal model with which to explore how phylogenetic and phylogeographic analyses of DNA-sequence data can inform understanding of evolutionary history and present-day biology. We review what has been learned of the phylogeny of the group and the phylogeographic history of individual species. We conclude that there is now a strong framework within which to pursue the remaining species-level taxonomic issues, and to extend ecological and behavioural studies into a new era of more detailed genetic questions such as the role of gene–environment interactions in adaptation. We highlight some remaining examples of such questions and discuss how they might be addressed.Organismic and Evolutionary Biolog

Childhood vaccinations: A pilot study on knowledge, attitudes and vaccine hesitancy in pregnant women

Background. The objective of this pilot study was to test a questionnaire aimed at assessing knowledge of and attitudes towards vaccination, as well as intention to vaccinate, among pregnant women. Methods. The questionnaire was self-administered by 49 pregnant women attending antenatal classes at three Family Centers in Rome. Results. Poor knowledge of vaccinations, inadequate attention from healthcare professionals, recurrent consultation of unreliable sources of information, and misconceptions about the side effects of vaccines, all contribute to vaccine hesitancy. Where appropriate, questionnaire sections were shown to be internally consistent. Conclusion. The questionnaire proved reliable and is suitable for further studies

Artificial Intelligence in Government Services: A Systematic Literature Review

The aim of this paper is to provide an overview on how artificial intelligence is shaping the digital era, in policy making and governmental terms. In doing so, it discloses new opportunities and discusses its implications to be considered by policy-makers. The research uses a systematic literature review, which includes more than one technique of data analysis in order to generate comprehensiveness and rich knowledge, we use: a bibliometric analysis and a content analysis. While artificial intelligence is identified as an extension of digital transformation, the results suggest the need to deepen scientific research in the fields of public administration, governmental law and business economics, areas where digital transformation still stands out from artificial intelligence. Although bringing together public and private sectors, to collaborate in the public service delivery, presents major advantages to policy makers, evidence has also shown the existence of negative effects of such collaboration.info:eu-repo/semantics/publishedVersio