2,216 research outputs found
Progress in Tourism Management: Is urban tourism a paradoxical research domain? Progress since 2011 and prospects for the future
© 2023 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).This paper reviews progress in the field of urban tourism, revisiting and challenging the validity of the paradoxes presented in the paper by Ashworth and Page (2011). To do this, the paper examines the expansion of research endeavours in urban tourism in relation to these paradoxes, including the outputs in dedicated journals on city tourism along with the wider range of outputs generated since 2011 in social science. It also revisits the initial proposition set out regarding an imbalance in attention in urban tourism research (Ashworth 1989, 2003) and how this has been addressed through a broader development of thinking at the intersection of urbanism and tourism. It is a selective review of progress in the field, highlighting the challenges of deriving theory from western modes of analysis that need re-thinking in relation to the global south, notably Africa as well as developments in Asia and the Middle East.Peer reviewe
A Mathematical Approach to the Study of the United States Code
The United States Code (Code) is a document containing over 22 million words
that represents a large and important source of Federal statutory law. Scholars
and policy advocates often discuss the direction and magnitude of changes in
various aspects of the Code. However, few have mathematically formalized the
notions behind these discussions or directly measured the resulting
representations. This paper addresses the current state of the literature in
two ways. First, we formalize a representation of the United States Code as the
union of a hierarchical network and a citation network over vertices containing
the language of the Code. This representation reflects the fact that the Code
is a hierarchically organized document containing language and explicit
citations between provisions. Second, we use this formalization to measure
aspects of the Code as codified in October 2008, November 2009, and March 2010.
These measurements allow for a characterization of the actual changes in the
Code over time. Our findings indicate that in the recent past, the Code has
grown in its amount of structure, interdependence, and language.Comment: 5 pages, 6 figures, 2 tables
Multi-Scale Entropy Analysis as a Method for Time-Series Analysis of Climate Data
Evidence is mounting that the temporal dynamics of the climate system are changing at the same time as the average global temperature is increasing due to multiple climate forcings. A large number of extreme weather events such as prolonged cold spells, heatwaves, droughts and floods have been recorded around the world in the past 10 years. Such changes in the temporal scaling behaviour of climate time-series data can be difficult to detect. While there are easy and direct ways of analysing climate data by calculating the means and variances for different levels of temporal aggregation, these methods can miss more subtle changes in their dynamics. This paper describes multi-scale entropy (MSE) analysis as a tool to study climate time-series data and to identify temporal scales of variability and their change over time in climate time-series. MSE estimates the sample entropy of the time-series after coarse-graining at different temporal scales. An application of MSE to Central European, variance-adjusted, mean monthly air temperature anomalies (CRUTEM4v) is provided. The results show that the temporal scales of the current climate (1960–2014) are different from the long-term average (1850–1960). For temporal scale factors longer than 12 months, the sample entropy increased markedly compared to the long-term record. Such an increase can be explained by systems theory with greater complexity in the regional temperature data. From 1961 the patterns of monthly air temperatures are less regular at time-scales greater than 12 months than in the earlier time period. This finding suggests that, at these inter-annual time scales, the temperature variability has become less predictable than in the past. It is possible that climate system feedbacks are expressed in altered temporal scales of the European temperature time-series data. A comparison with the variance and Shannon entropy shows that MSE analysis can provide additional information on the statistical properties of climate time-series data that can go undetected using traditional method
Development and testing of a risk indexing framework to determine field-scale critical source areas of faecal bacteria on grassland.
This paper draws on lessons from a UK case study in the management of diffuse microbial pollution from grassland farm systems in the Taw catchment, south west England. We report on the development and preliminary testing of a field-scale faecal indicator organism risk indexing tool (FIORIT). This tool aims to prioritise those fields most vulnerable in terms of their risk of contributing FIOs to water. FIORIT risk indices were related to recorded microbial water quality parameters (faecal coliforms [FC] and intestinal enterococci [IE]) to provide a concurrent on-farm evaluation of the tool. There was a significant upward trend in Log[FC] and Log[IE] values with FIORIT risk score classification (r2 =0.87 and 0.70, respectively and P<0.01 for both FIOs). The FIORIT was then applied to 162 representative grassland fields through different seasons for ten farms in the case study catchment to determine the distribution of on-farm spatial and temporal risk. The high risk fields made up only a small proportion (1%, 2%, 2% and 3% for winter, spring, summer and autumn, respectively) of the total number of fields assessed (and less than 10% of the total area), but the likelihood of the hydrological connection of high FIO source areas to receiving watercourses makes them a priority for mitigation efforts. The FIORIT provides a preliminary and evolving mechanism through which we can combine risk assessment with risk communication to end-users and provides a framework for prioritising future empirical research. Continued testing of FIORIT across different geographical areas under both low and high flow conditions is now needed to initiate its long term development into a robust indexing tool
Efficacy of an Avian Repellent Applied Using Drop Nozzle-Equipped Ground Rigs in Reducing Blackbird Damage to Sunflower
In North Dakota large flocks of blackbirds feed on ripening crops, after breeding and prior to migration, resulting in an annual damage estimate averaging $3.5 million for sunflower. Since the repellent needs to be ingested to be effective, one obstacle is applying sufficient repellent directly to the sunflower face. Thus, we tested efficacy of an anthraquinone-based repellent when applied via drop-nozzle to sunflower using enclosed blackbirds in a semi-natural field setting. We used a ground-rig equipped with 360 Undercover® drop nozzle sprayers to apply 20 gal/ac of solution to sunflower plots with a product application rate of 1.0 gal/ac (13% AQ). To test efficacy, we installed bird enclosures (12 x 13 x 10 ft) to house 10 captive, male red-winged blackbirds (Agelaius phoeniceus) for 23 days on 10 treated and 10 untreated plots. The repellent did not cause birds to consume more alternative diet (i.e., red milo). Sunflower yield did not differ between treated and untreated enclosures as a result of blackbird damage. Variation in the amount of repellent reaching the face of the sunflower and subsequent residues was a limitation of the application method. Efficacy may be improved by increasing the application rate or repellent in the tank mixture, but sprayer technology and economic limitations related to repellent costs need to be considered. Future studies should aim to optimize the amount of product in tank mixtures and the repellent formulation as designed for specific pests and crops
Hybrid meson decay from the lattice
We discuss the allowed decays of a hybrid meson in the heavy quark limit. We
deduce that an important decay will be into a heavy quark non-hybrid state and
a light quark meson, in other words, the de-excitation of an excited gluonic
string by emission of a light quark-antiquark pair.
We discuss the study of hadronic decays from the lattice in the heavy quark
limit and apply this approach to explore the transitions from a spin-exotic
hybrid to and where is a scalar meson. We obtain a
signal for the transition emitting a scalar meson and we discuss the
phenomenological implications.Comment: 18 pages, LATEX, 3 ps figure
Negative vacuum energy densities and the causal diamond measure
Arguably a major success of the landscape picture is the prediction of a
small, non-zero vacuum energy density. The details of this prediction depends
in part on how the diverging spacetime volume of the multiverse is regulated, a
question that remains unresolved. One proposal, the causal diamond measure, has
demonstrated many phenomenological successes, including predicting a
distribution of positive vacuum energy densities in good agreement with
observation. In the string landscape, however, the vacuum energy density is
expected to take positive and negative values. We find the causal diamond
measure gives a poor fit to observation in such a landscape -- in particular,
99.6% of observers in galaxies seemingly just like ours measure a vacuum energy
density smaller than we do, most of them measuring it to be negative.Comment: 9 pages, 3 figures; v2: minor error fixed (results essentially
unchanged), reference added; v3: published version, includes a few
clarification
Hadronic Parity Violation: a New View through the Looking Glass
Studies of the strangeness changing hadronic weak interaction have produced a
number of puzzles that have so far evaded a complete explanation within the
Standard Model. Their origin may lie either in dynamics peculiar to weak
interactions involving strange quarks or in more general aspects of the
interplay between strong and weak interactions. In principle, studies of the
strangeness conserving hadronic weak interaction using parity violating
hadronic and nuclear observables provide a complementary window on this
question. However, progress in this direction has been hampered by the lack of
a suitable theoretical framework for interpreting hadronic parity violation
measurements in a model-independent way. Recent work involving effective field
theory ideas has led to the formulation of such a framework while motivating
the development of a number of new hadronic parity violation experiments in
few-body systems. In this article, we review these recent developments and
discuss the prospects and opportunities for further experimental and
theoretical progress.Comment: Manuscript submitted to Annual Reviews of Nuclear and Particle
Scienc
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