Interaction of Kelvin waves and nonlocality of energy transfer in superfluids

We argue that the physics of interacting Kelvin Waves (KWs) is highly nontrivial and cannot be understood on the basis of pure dimensional reasoning. A consistent theory of KW turbulence in superfluids should be based upon explicit knowledge of their interactions. To achieve this, we present a detailed calculation and comprehensive analysis of the interaction coefficients for KW turbuelence, thereby, resolving previous mistakes stemming from unaccounted contributions. As a first application of this analysis, we derive a local nonlinear (partial differential) equation. This equation is much simpler for analysis and numerical simulations of KWs than the Biot-Savart equation, and in contrast to the completely integrable local induction approximation (in which the energy exchange between KWs is absent), describes the nonlinear dynamics of KWs. Second, we show that the previously suggested Kozik-Svistunov energy spectrum for KWs, which has often been used in the analysis of experimental and numerical data in superfluid turbulence, is irrelevant, because it is based upon an erroneous assumption of the locality of the energy transfer through scales. Moreover, we demonstrate the weak nonlocality of the inverse cascade spectrum with a constant particle-number flux and find resulting logarithmic corrections to this spectrum

Coordination of international multicenter studies: Governance and administrative structure

A well-conducted multicenter study needs to assure standardization, uniformity of procedures, high data quality, and collaboration across sites. This manuscript describes the organization and dynamics of multicenter studies, focusing on governance and administrative structures among countries of diverse cultures. the organizational structure of a multicenter study is described, and a system for oversight and coordination, along with roles and responsibilities of participants in the multicenter study, are presented. the elements of a governance document are also reviewed, along with guidelines and policies for effective collaboration. the experience of an ongoing multi-country collaboration, the World Studies of Abuse in the Family Environment (World-SAFE), illustrates the implementation of these guidelines. It is essential that multicenter studies have an objective coordinating center and that the investigators jointly develop a written governance document to enable collaboration and preserve collegiality among participating investigators. the English version of this paper is available too at: http://www.insp.mx/salud/index.html.Univ N Carolina, Chapel Hill, NC USAUniversidade Federal de São Paulo, Escola Paulista Med, São Paulo, BrazilUniv Philippines, Manila, PhilippinesUniv La Frontera, Temuco, ChileUniversidade Federal de São Paulo, Escola Paulista Med, São Paulo, BrazilWeb of Scienc

Academic Library and Publisher Collaboration: Utilizing an Institutional Repository to Maximize the Visibility and Impact of Articles by University Authors

The George A. Smathers Libraries (Libraries) (http://www.uflib.ufl.edu/) at the University of Florida (UF) (http://www.ufl.edu/) and Elsevier (http://www.elsevier.com) have embarked on a pilot project to maximize visibility, impact, and dissemination of articles by UF researchers who have published in Elsevier journals. Article links and metadata are automatically delivered to UF’s Institutional Repository, the IR@UF (http://ufdc.ufl.edu/ir), in the IR@UF-Elsevier Collection (http://ufdc.ufl.edu/ielsevier). The metadata, with links for approximately 31,000 articles by UF authors, is made possible through integration of the IR@UF with the ScienceDirect application programming interfaces (APIs) (https://www.elsevier.com/solutions/sciencedirect/support/institutional-repository) that are freely available to libraries. Access to the full text on ScienceDirect is available for all institutional repository users affiliated with a subscribing institution. In the next phase users without subscriptions will be able to access the manuscripts of articles published from 2013 forward. This will be done by embedding metadata and links to accepted manuscripts available on ScienceDirect into the IR@UF. We will conduct user and usability testing of this cross-platform user experience. This article provides an overview of the project’s current status, how it works, what it delivers, and next steps expanding the project to include articles by UF authors from other publishers. It concludes with strategic considerations, future developments, and reflections on the value of library/publisher collaboration

Evaluation of fecal mRNA reproducibility via a marginal transformed mixture modeling approach

<p>Abstract</p> <p>Background</p> <p>Developing and evaluating new technology that enables researchers to recover gene-expression levels of colonic cells from fecal samples could be key to a non-invasive screening tool for early detection of colon cancer. The current study, to the best of our knowledge, is the first to investigate and report the reproducibility of fecal microarray data. Using the intraclass correlation coefficient (ICC) as a measure of reproducibility and the preliminary analysis of fecal and mucosal data, we assessed the reliability of mixture density estimation and the reproducibility of fecal microarray data. Using Monte Carlo-based methods, we explored whether ICC values should be modeled as a beta-mixture or transformed first and fitted with a normal-mixture. We used outcomes from bootstrapped goodness-of-fit tests to determine which approach is less sensitive toward potential violation of distributional assumptions.</p> <p>Results</p> <p>The graphical examination of both the distributions of ICC and probit-transformed ICC (PT-ICC) clearly shows that there are two components in the distributions. For ICC measurements, which are between 0 and 1, the practice in literature has been to assume that the data points are from a beta-mixture distribution. Nevertheless, in our study we show that the use of a normal-mixture modeling approach on PT-ICC could provide superior performance.</p> <p>Conclusions</p> <p>When modeling ICC values of gene expression levels, using mixture of normals in the probit-transformed (PT) scale is less sensitive toward model mis-specification than using mixture of betas. We show that a biased conclusion could be made if we follow the traditional approach and model the two sets of ICC values using the mixture of betas directly. The problematic estimation arises from the sensitivity of beta-mixtures toward model mis-specification, particularly when there are observations in the neighborhood of the the boundary points, 0 or 1. Since beta-mixture modeling is commonly used in approximating the distribution of measurements between 0 and 1, our findings have important implications beyond the findings of the current study. By using the normal-mixture approach on PT-ICC, we observed the quality of reproducible genes in fecal array data to be comparable to those in mucosal arrays.</p

Dynamics of Transformation from Segregation to Mixed Wealth Cities

We model the dynamics of the Schelling model for agents described simply by a continuously distributed variable - wealth. Agents move to neighborhoods where their wealth is not lesser than that of some proportion of their neighbors, the threshold level. As in the case of the classic Schelling model where segregation obtains between two races, we find here that wealth-based segregation occurs and persists. However, introducing uncertainty into the decision to move - that is, with some probability, if agents are allowed to move even though the threshold level condition is contravened - we find that even for small proportions of such disallowed moves, the dynamics no longer yield segregation but instead sharply transition into a persistent mixed wealth distribution. We investigate the nature of this sharp transformation between segregated and mixed states, and find that it is because of a non-linear relationship between allowed moves and disallowed moves. For small increases in disallowed moves, there is a rapid corresponding increase in allowed moves, but this tapers off as the fraction of disallowed moves increase further and finally settles at a stable value, remaining invariant to any further increase in disallowed moves. It is the overall effect of the dynamics in the initial region (with small numbers of disallowed moves) that shifts the system away from a state of segregation rapidly to a mixed wealth state. The contravention of the tolerance condition could be interpreted as public policy interventions like minimal levels of social housing or housing benefit transfers to poorer households. Our finding therefore suggests that it might require only very limited levels of such public intervention - just sufficient to enable a small fraction of disallowed moves, because the dynamics generated by such moves could spur the transformation from a segregated to mixed equilibrium.Comment: 12 pages, 7 figure

Modeling Kelvin wave cascades in superfluid helium

We study two different types of simplified models for Kelvin wave turbulence on quantized vortex lines in superfluids near zero temperature. Our first model is obtained from a truncated expansion of the Local Induction Approximation (Truncated-LIA) and it is shown to possess the same scalings and the essential behaviour as the full Biot-Savart model, being much simpler than the later and, therefore, more amenable to theoretical and numerical investigations. The Truncated-LIA model supports six-wave interactions and dual cascades, which are clearly demonstrated via the direct numerical simulation of this model in the present paper. In particular, our simulations confirm presence of the weak turbulence regime and the theoretically predicted spectra for the direct energy cascade and the inverse wave action cascade. The second type of model we study, the Differential Approximation Model (DAM), takes a further drastic simplification by assuming locality of interactions in k-space via using a differential closure that preserves the main scalings of the Kelvin wave dynamics. DAMs are even more amenable to study and they form a useful tool by providing simple analytical solutions in the cases when extra physical effects are present, e.g. forcing by reconnections, friction dissipation and phonon radiation. We study these models numerically and test their theoretical predictions, in particular the formation of the stationary spectra, and closeness of numerics for the higher-order DAM to the analytical predictions for the lower-order DAM

Evidence of plant and animal communities at exposed and subglacial (cave) geothermal sites in Antarctica

Geothermal areas, such as volcanoes, might have acted as glacial microrefugia for a wide range of species. The heavily glaciated but volcanically active Antarctic continent presents an ideal system for assessing this hypothesis. Ice-free terrain around volcanoes in Antarctica is, however, often restricted to small patches, whereas subglacial cave systems, formed by vented volcanic steam, can be extensive and interconnected. No observations of macrobiota have yet been made for subglacial geothermal environments in Antarctica, but these organisms are often patchily distributed and can be difficult to find. We carried out metabarcoding (eDNA) analyses of soil samples taken from exposed areas on three volcanoes in Victoria Land, and subglacial caves on Mount Erebus. We found evidence of numerous eukaryotic groups, including mosses, algae, arthropods, oligochaetes and nematodes, at both exposed and subglacial sites. Our findings support the notion that geothermal areas—including subglacial environments—can nurture biodiversity in glaciated regions

Actuación en zonas antiguas de pueblos y ciudades

Actuación en zonas antiguas de pueblos y ciudade

How to achieve true integration: the impact of Integrated Marketing Communication on the Client/Agency Relationship

Reports from the advertising industry suggest that the pressure to create effective integrated campaigns across the ever-increasing mix of paid, owned and earned media is putting an enormous strain on client/agency relationships. This research identifies the main challenges that an Integrated Marketing Communication (IMC) approach places on this relationship and thereby advances the IMC literature by examining the practical challenges of implementation. Six key issues, developed from academic and industry sources, are presented to advertising experts, through a Delphi study, to stimulate debate and identify areas of agreement. The findings are brought together in a model which presents three main areas that need to be addressed, along with specific recommendations. These topics include the need for clients to provide stronger leadership in defining agency roles and responsibilities, more transparent remuneration systems to encourage teamwork across agencies as well as individual input and an increased emphasis on the strategic contribution from agencies

Translation urgency in our climate-challenged times : co-producing geographical knowledge on El Niño in Peru

This paper was developed as part of the Leverhulme award MRF-2022-065. Fieldwork was supported by AHRC grants (AH/T004444/1AH, AH/V012215/1) and exchange activities (2023) by the Scottish Alliance for Geoscience, Environment and Society (SAGES).This paper makes a case for revisiting the understandings of translation to enhance the co-production of geographical knowledge on climate change. Specifically, it offers insights about the potential role that schoolteachers and students can have as knowledge producers in relation to climate change by drawing on a case study of collaborative research on El Niño in Sechura, northern Peru. We call for researchers to pay greater attention to how co-production can be achieved through the integration of research agendas and practice with curricula development and innovation in school education. We contribute to work on how a generational shift in understanding about climate adaptation can be achieved through exploring communities’ knowledge of the lesser-known opportunities of the El Niño phenomenon in northern desert regions. We conclude by arguing that revisiting how geography engages in and with translation is an urgent priority in climate-challenged times.Peer reviewe