Poisson splitting by factors

Given a homogeneous Poisson process on ${\mathbb{R}}^d$ with intensity $\lambda$, we prove that it is possible to partition the points into two sets, as a deterministic function of the process, and in an isometry-equivariant way, so that each set of points forms a homogeneous Poisson process, with any given pair of intensities summing to $\lambda$. In particular, this answers a question of Ball [Electron. Commun. Probab. 10 (2005) 60--69], who proved that in $d=1$, the Poisson points may be similarly partitioned (via a translation-equivariant function) so that one set forms a Poisson process of lower intensity, and asked whether the same is possible for all $d$. We do not know whether it is possible similarly to add points (again chosen as a deterministic function of a Poisson process) to obtain a Poisson process of higher intensity, but we prove that this is not possible under an additional finitariness condition.Comment: Published in at http://dx.doi.org/10.1214/11-AOP651 the Annals of Probability (http://www.imstat.org/aop/) by the Institute of Mathematical Statistics (http://www.imstat.org

Poisson splitting by factors

This is the published version, also available here: http://dx.doi.org/10.1214/11-AOP651.Given a homogeneous Poisson process on ℝd with intensity λ, we prove that it is possible to partition the points into two sets, as a deterministic function of the process, and in an isometry-equivariant way, so that each set of points forms a homogeneous Poisson process, with any given pair of intensities summing to λ. In particular, this answers a question of Ball [Electron. Commun. Probab. 10 (2005) 60–69], who proved that in d = 1, the Poisson points may be similarly partitioned (via a translation-equivariant function) so that one set forms a Poisson process of lower intensity, and asked whether the same is possible for all d. We do not know whether it is possible similarly to add points (again chosen as a deterministic function of a Poisson process) to obtain a Poisson process of higher intensity, but we prove that this is not possible under an additional finitariness condition

High-Precision Entropy Values for Spanning Trees in Lattices

Shrock and Wu have given numerical values for the exponential growth rate of the number of spanning trees in Euclidean lattices. We give a new technique for numerical evaluation that gives much more precise values, together with rigorous bounds on the accuracy. In particular, the new values resolve one of their questions.Comment: 7 pages. Revision mentions alternative approach. Title changed slightly. 2nd revision corrects first displayed equatio

Fluid/solid transition in a hard-core system

We prove that a system of particles in the plane, interacting only with a certain hard-core constraint, undergoes a fluid/solid phase transition

Epilogue: the new frontiers of behavioral research on the interrelationships between ICT, activities, time use and mobility

© 2018, Springer Science+Business Media, LLC, part of Springer Nature. This special issue is a product of the international symposium on “ICT, Activities, Time Use and Travel” that was hosted by Nanjing University from 16 to 18 July 2016. The symposium brought together leading scholars from all over the world to congregate with Chinese scholars and students and to share and discuss the research frontiers at this nexus. It was motivated by a recognition of the changing goals and scope of Information and Communications Technology (ICT) research in conjunction with the development of new ICTs and the emergence of new ICT-enabled behaviors. Consequently, the symposium and later this special issue have drawn together significant scholarly contributions that provide new behavioral insights as well as new theoretical and methodological advances. The symposium culminated in three roundtable panel discussions addressing the following cross-cutting themes: (1) time use while travelling (led by Glenn Lyons); (2) ICT and travel behavior (led by Pat Mokhtarian); and (3) Big Data, activities and urban space (led by Eran Ben-Elia). In this epilogue to the special issue we offer a distillation of these discussions

Phase Transitions on Nonamenable Graphs

We survey known results about phase transitions in various models of statistical physics when the underlying space is a nonamenable graph. Most attention is devoted to transitive graphs and trees

Sismicità all’Etna dal 1989 al 2010: evidenze sull’evoluzione spazio-temporale dell’attività sismica

Il Monte Etna, uno dei più attivi vulcani basaltici tra i più monitorati al mondo, è sede di una notevole attività sismica e vulcanica. Esso è ubicato in Sicilia orientale in un complesso quadro geodinamico, dove le principali strutture tettoniche regionali giocano un ruolo chiave nei processi dinamici del vulcano. La sismicità dell’Etna si manifesta con un elevato rate di terremoti di bassa e moderata energia che, a volte, a causa dell’estrema superficialità della sorgente, provocano danni ai centri abitati prossimi all’area epicentrale. Il monitoraggio sistematico dell’attività sismica etnea è effettuato sin dal 1989, mediante una rete sismica locale permanente che nel tempo è stata oggetto di importanti miglioramenti. La prima configurazione di rete era costituita da circa 10 stazioni analogiche con sensori a corto periodo gestita dall’Istituto Internazionale di Vulcanologia (IIV-CNR). Nel 1994, una rete sismica costituita da circa 40 stazioni (analogiche con sensori a corto periodo) fu installata sull’Etna nell’ambito del Progetto Poseidon. Nel 2001, le reti gestite dall’IIV-CNR e dal Progetto Poseidon confluirono nell’Istituto Nazionale di Geofisica e Vulcanologia (INGV); attualmente la rete sismica, costituita da circa 50 stazioni digitali equipaggiate con sismometri broadband a tre componenti, è gestita dalla Sezione di Catania dell’INGV. Nel periodo 1989-1999, il catalogo dei terremoti risulta costituito da circa 2000 eventi con soglia di completezza per magnitudo pari a 2.0; dal 1999 ad oggi contiene circa 6000 terremoti con soglia di completezza per magnitudo 1.5. La capacità di detezione della rete è migliorata nel tempo permettendo di registrare e localizzare anche gli eventi meno energetici (M≥1.0). In questo lavoro, vengono presentati i caratteri predominanti della sismicità etnea negli ultimi 20 anni, con un maggiore dettaglio della distribuzione spazio-temporale della sismicità verificatasi dal 1999. L’analisi della attività sismica rappresenta un utile strumento per l’interpretazione delle dinamiche che hanno contraddistinto numerose ed importanti eruzioni (2001, 2002-03, 2004, 2006, 2008-09). In particolare, la variazione del rilascio energetico della sismicità ha contribuito in maniera significativa ad identificare i probabili processi geodinamici legati alla ricarica del sistema magmatico del vulcano. La distribuzione spaziale della sismicità ha consentito di evidenziare inoltre l’esistenza di diverse aree sismogenetiche caratterizzate da un differente rate sismico, profondità focali e cinematica delle strutture associate. Infine, osservando le caratteristiche della sismicità nel lungo periodo, differenti settori del vulcano sono risultati maggiormente attivi in relazione ai più importanti recenti eventi eruttivi

Using knowledge brokers to facilitate the uptake of pediatric measurement tools into clinical practice: a before-after intervention study

<p>Abstract</p> <p>Background</p> <p>The use of measurement tools is an essential part of good evidence-based practice; however, physiotherapists (PTs) are not always confident when selecting, administering, and interpreting these tools. The purpose of this study was to evaluate the impact of a multifaceted knowledge translation intervention, using PTs as knowledge brokers (KBs) to facilitate the use in clinical practice of four evidence-based measurement tools designed to evaluate and understand motor function in children with cerebral palsy (CP). The KB model evaluated in this study was designed to overcome many of the barriers to research transfer identified in the literature.</p> <p>Methods</p> <p>A mixed methods before-after study design was used to evaluate the impact of a six-month KB intervention by 25 KBs on 122 practicing PTs' self-reported knowledge and use of the measurement tools in 28 children's rehabilitation organizations in two regions of Canada. The model was that of PT KBs situated in clinical sites supported by a network of KBs and the research team through a broker to the KBs. Modest financial remuneration to the organizations for the KB time (two hours/week for six months), ongoing resource materials, and personal and intranet support was provided to the KBs. Survey data were collected by questionnaire prior to, immediately following the intervention (six months), and at 12 and 18 months. A mixed effects multinomial logistic regression was used to examine the impact of the intervention over time and by region. The impact of organizational factors was also explored.</p> <p>Results</p> <p>PTs' self-reported knowledge of all four measurement tools increased significantly over the six-month intervention, and reported use of three of the four measurement tools also increased. Changes were sustained 12 months later. Organizational culture for research and supervisor expectations were significantly associated with uptake of only one of the four measurement tools.</p> <p>Conclusions</p> <p>KBs positively influenced PTs' self-reported knowledge and self-reported use of the targeted measurement tools. Further research is warranted to investigate whether this is a feasible, cost-effective model that could be used more broadly in a rehabilitation setting to facilitate the uptake of other measurement tools or evidence-based intervention approaches.</p

Commute replacement and commute displacement the rise of part-day home working

Working by telecommunication has been the subject of research attention in transportation studies for many years. Particular consideration has been given to occasional working from home (home working) by (full-time, paid) employees who represent a tangible removal of commute trips on days that people work from home. However, little recognition or attention has been given to the fact that home working not only may be undertaken for part of a week but also may be undertaken for parts of given days. This paper focuses particularly on part-day home working. It defines and uses the term "varied spatiotemporal (VST) working" to describe working days in which at least 30 min of continuous working takes place at home accompanied by work taking place at the workplace. Notably, such home working does not remove the commute trips but can temporally displace one or both of them. The research reported in this paper builds on preceding survey work that had established that the number of people who practice VST working and the number of VST days worked appear to be about double those for full-day home working (which has typically been the focus of research attention). The results presented in this paper are based on 25 in-depth interviews with individuals who practice VST working. The aim of the research was to examine more closely and to understand the nature of VST working and the motivations and constraints for its practice and to consider its potential contribution as a transportation demand management measure