In the project "statistical image analysis" of CWI we have studied some spatial point patterns that originated from biological observations. These observations were the positions of so called EGF‐receptors on the surface of human carcinoma cells.We propose a stochastic model for these point patterns. Since the EGF‐receptors appear in clusters on the cell surface, we have opted for the Poisson‐cluster‐process as the model. We estimated the three parameters in this process by means of a method described by Diggle. We also did some work in assessing the statistical reliability of our estimates.
As the Internet becomes more and more embedded in every sector of society, more and more actors have become concerned with its character, now and in the future. The private sector actors, such as Internet Service Providers or ISPs, are motivated by profits as they shape and evolve the Internet. The public sector is driven by a range of objectives: access and uptake, competition policy, regime stability, policies with regard to controlling access to classes of content, and the like. The range of actions open to governments to shape the Internet are traditional and well-understood, including law and regulation, procurement, investment in research and development, participation in the standards process and more diffuse forms of leadership. But these actions do not directly shape the Internet. They bear on the actors that in turn have direct influence over the Internet and what happens there. Thus, as part of any conversation about the shaping of the Internet, there is a narrower question that must be answered: given the Internet as it is today, who are the actors that can exercise direct control over how it works, what options for control do they actually have, and how can they in turn be influenced? ; This material is based on work supported by the U.S. Office of Naval Research, Grant No. N00014-09-1-0597. Any opinions, findings, conclusions or recommendations therein are those of the author(s) and do not necessarily reflect the views of the Office of Naval Research.
Abstract. We test the hypothesis that critical point dynamics precedes strong earthquakes in a region surrounding the future hypocenter. Therefore, we search systematically for regions obeying critical point dynamics in terms of a growing spatial correlation length (GCL). The question of whether or not these spatial patterns are correlated with future seismicity is crucial for the problem of predictability. The analysis is conducted for earthquakes with M > 6.5 in California. As a result, we observe that GCL patterns are correlated with the distribution of future seismicity. In particular, there are clear correlations in some cases, e.g. the 1989 Loma Prieta earthquake and the 1999 Hector Mine earthquake. We claim that the critical point concept can improve the seismic hazard assessment.
The strength and range of interpoint interactions in a spatial point process can be quantified by the function J = (1 ‐ G)/(1 ‐ F), where G is the nearest‐neighbour distance distribution function and F the empty space function of the process. J(r) is identically equal to 1 for a Poisson process; values of J(r) smaller or larger than 1 indicate clustering or regularity, respectively. We show that, for a large class of point processes, J(r) is constant for distances r greater than the range of spatial interaction. Hence both the range and type of interaction can be inferred from J without parametric model assumptions. It is also possible to evaluate J(r) explicitly for many point process models, so that J is also useful for parameter estimation. Various properties are derived, including the fact that the J function of the superposition of independent point processes is a weighted mean of the J functions of the individual processes. Estimators of J can be constructed from standard estimators of F and G. We compute estimates of J for several standard point pattern datasets and implement a Monte Carlo test for complete spatial randomness.
SummaryData concerning occasions of coitus were recorded by 241 married couples who had sought advice from the Catholic Marriage Advisory Council about the basal body temperature method of regulating births. The present analysis deals with the 6 days of the post-ovulatory phase which are considered to be least affected by intended birth regulation. The distribution among couples of coital frequencies is tabulated by age of wife; the mean frequency during the 6 days is 1·8 (Table 2) but this value may be influenced by the fact that some couples had avoided coitus in the pre-ovulatory phase. The hypothesis is examined that the probability of coitus on any day is unaffected by whether or not coitus occurred on the previous day. Sufficient data are available to show, as expected, that not all couples behave in the way described by this hypothesis. It is estimated that for about a third of the couples the probability of coitus is decreased if it occurred on the previous day (alternators). There are also significant numbers for whom it is increased (persisters), besides those conforming to the hypothesis.
Instead of looking at individual nutrients or foods, dietary pattern analysis has emerged as a promising approach to examine the relationship between diet and health outcomes. Despite dietary patterns being compositional (i.e. usually a higher intake of some foods implies that less of other foods are being consumed), compositional data analysis has not yet been applied in this setting. We describe three compositional data analysis approaches (compositional principal component analysis, balances and principal balances) that enable the extraction of dietary patterns by using control subjects from the Spanish multicase-control (MCC-Spain) study. In particular, principal balances overcome the limitations of purely data-driven or investigator-driven methods and present dietary patterns as trade-offs between eating more of some foods and less of others. ; The author(s) disclosed receipt of the following financial support for the research, authorship, and/or publication of this article: The study was partially funded by the ''Accion Transversal del Cancer'', approved by the Spanish Ministry Council on 11 October 2007; by the Consortium for Biomedical Research in Epidemiology and Public Health (CIBERESP); by the Instituto de Salud Carlos III-FEDER (grant nos PI08/1770, PI08/0533, PI08/1359, PS09/00773-Cantabria, PS09/01286-Leo´n, PS09/ 01903-Valencia, PS09/02078-Huelva, PS09/01662-Granada, PI11/01403, PI11/01810, PI11/02213, PI12/00488, PI14/01219, PI14/0613, PI15/00069, PI15/00914, PI15/01032, PI17/01280, PI09/0914, IJCI-2014-20900); by the Spanish Ministry of Health (grant no. CB06/02/1002); by the Spanish Ministry of Economy and Competitiveness (grant no. MTM2015-65016- C2-1-R); by the Catalan Government-Agency for Management of University and Research Grants (AGAUR) (grant nos 2014SGR551, 2017SGR656, 2017SGR733, 2017SGR723, 2017SGR1085); by the University of Girona (grant no. MPCUdG2016/069, GDRCompetUdG2017/19); by the Fundacio´n Marque´s de Valdecilla (grant no. API 10/09); by the Junta de Castilla y Leo´n (grant no. LE22A10-2); by the Consejerı´a de Salud of the Junta de Andalucı´a (grant nos PI-0571- 2009, PI-0306-2011, salud201200057018tra); by the Conselleria de Sanitat of the Generalitat Valenciana (grant no. AP_061/10); by the Regional Government of the Basque Country; by the Consejerı´a de Sanidad de la Regio´n de Murcia; by the European Commission (FOOD-CT-2006-036224-HIWATE); by the Spanish Association Against Cancer (AECC) Scientific Foundation; by the Fundacio´n Caja de Ahorros de Asturias; and by the University of Oviedo. ISGlobal is a member of the CERCA Programme, Generalitat de Catalunya.
