2,594,956 research outputs found
Did language give us numbers? : Symbolic thinking and the emergence of systematic numerical cognition
What role does language play in the development of numerical cognition? In the present paper I argue that the evolution of symbolic thinking (as a basis for language) laid the grounds for the emergence of a systematic concept of number. This concept is grounded in the notion of an infinite sequence and encompasses number assignments that can focus on cardinal aspects ("three pencils"), ordinal aspects ("the third runner"), and even nominal aspects ("bus #3"). I show that these number assignments are based on a specific association of relational structures, and that it is the human language faculty that provides a cognitive paradigm for such an association, suggesting that language played a pivotal role in the evolution of systematic numerical cognition
Probabilistic positional association of catalogs of astrophysical sources: the Aspects code
We describe a probabilistic method of cross-identifying astrophysical sources
in two catalogs from their positions and positional uncertainties. The
probability that an object is associated with a source from the other catalog,
or that it has no counterpart, is derived under two exclusive assumptions:
first, the classical case of several-to-one associations, and then the more
realistic but more difficult problem of one-to-one associations.
In either case, the likelihood of observing the objects in the two catalogs
at their effective positions is computed and a maximum likelihood estimator of
the fraction of sources with a counterpart -- a quantity needed to compute the
probabilities of association -- is built. When the positional uncertainty in
one or both catalogs is unknown, this method may be used to estimate its
typical value and even to study its dependence on the size of objects. It may
also be applied when the true centers of a source and of its counterpart at
another wavelength do not coincide.
To compute the likelihood and association probabilities under the different
assumptions, we developed a Fortran 95 code called "Aspects" ([asp{\epsilon}],
"ASsociation PositionnellE/ProbabilistE de CaTalogues de Sources" in French);
its source files are made freely available. To test Aspects, all-sky mock
catalogs containing up to 10^5 objects were created, forcing either
several-to-one or one-to-one associations. The analysis of these simulations
confirms that, in both cases, the assumption with the highest likelihood is the
right one and that estimators of unknown parameters built for the appropriate
association model are reliable.Comment: One typo corrected and links added. One-column format (A&A official
version is in two-column format). 20 pages, 5 figures. Version 2 of code
Aspects available at http://www2.iap.fr/users/fioc/Aspects/ . Detailed
documentation and complements at arXiv:1404.4224. Numerical Recipes routines
not needed anymor
Recommended from our members
A brief history of the British Neuroscience Association
As the British Neuroscience Association commemorates 50 years of existence in 2018, this article recalls its founding as a discussion group, its establishment as the Brain Research Association, its transition to a professional society encompassing all aspects of neuroscience research, both clinical and non-clinical, and its re-branding as the British Neuroscience Association in the late 1990s. Neuroscience as a branch of life science has expanded hugely in the last 25 years and the British Neuroscience Association has adapted, frequently working with partner societies, to serve as an interdisciplinary hub for professionals working in this exciting and crucial field. The authors have attempted to highlight some key events in the Association’s history and acknowledge the contributions made by many people over half a century
The Future of Citizenship
A discussion of what constitutes identity and citizenship is timely and welcome. The linkage of
citizenship to history and the association of citizenship with rights and responsibilities are
appropriate. Nonetheless, we have concerns with some aspects of the discussion on citizenship
Kernel-based aggregation of marker-level genetic association tests involving copy-number variation
Genetic association tests involving copy-number variants (CNVs) are
complicated by the fact that CNVs span multiple markers at which measurements
are taken. The power of an association test at a single marker is typically
low, and it is desirable to pool information across the markers spanned by the
CNV. However, CNV boundaries are not known in advance, and the best way to
proceed with this pooling is unclear. In this article, we propose a
kernel-based method for aggregation of marker-level tests and explore several
aspects of its implementation. In addition, we explore some of the theoretical
aspects of marker-level test aggregation, proposing a permutation-based
approach that preserves the family-wise error rate of the testing procedure,
while demonstrating that several simpler alternatives fail to do so. The
empirical power of the approach is studied in a number of simulations
constructed from real data involving a pharmacogenomic study of gemcitabine,
and compares favorably with several competing approaches
Association between time to reperfusion and outcome is primarily driven by the time from imaging to reperfusion
Background and Purpose A progressive decline in the odds of favorable outcome as time to reperfusion increases is well known. However, the impact of specific workflow intervals is not clear.; Methods We studied the mechanical thrombectomy group (n=103) of the prospective, randomized REVASCAT (Randomized Trial of Revascularization With Solitaire FR Device Versus Best Medical Therapy in the Treatment of Acute Stroke due to Anterior Circulation Large Vessel Occlusion Presenting Within Eight Hours of Symptom Onset) trial. We defined 3 workflow metrics: time from symptom onset to reperfusion (OTR), time from symptom onset to computed tomography, and time from computed tomography (CT) to reperfusion. Clinical characteristics, core laboratory-evaluated Alberta Stroke Program Early CT Scores (ASPECTS) and 90-day outcome data were analyzed. The effect of time on favorable outcome (modified Rankin scale, 0-2) was described via adjusted odds ratios (ORs) for every 30-minute delay.; Results Median admission National Institutes of Health Stroke Scale was 17.0 (14.0-20.0), reperfusion rate was 66%, and rate of favorable outcome was 43.7%. Mean (SD) workflow times were as follows: OTR: 342 (107) minute, onset to CT: 204 (93) minute, and CT to reperfusion: 138 (56) minute. Longer OTR time was associated with a reduced likelihood of good outcome (OR for 30-minute delay, 0.74; 95% confidence interval [CI], 0.59-0.93). The onset to CT time did not show a significant association with clinical outcome (OR, 0.87; 95% CI, 0.67-1.12), whereas the CT to reperfusion interval showed a negative association with favorable outcome (OR, 0.72; 95% CI, 0.54-0.95). A similar subgroup analysis according to admission ASPECTS showed this relationship for OTR time in ASPECTS<8 patients (OR, 0.56; 95% CI, 0.35-0.9) but not in ASPECTS8 (OR, 0.99; 95% CI, 0.68-1.44).; Conclusions Time to reperfusion is negatively associated with favorable outcome, being CT to reperfusion, as opposed to onset to CT, the main determinant of this association. In addition, OTR was strongly associated to outcome in patients with low ASPECTS scores but not in patients with high ASPECTS scores.; Clinical Trial Registration URL: http://www.clinicaltrials.gov. Unique identifier: NCT01692379.Peer ReviewedPostprint (author's final draft
Urban environmental health applications of remote sensing, summary report
Health and its association with the physical environment was studied based on the hypothesis that there is a relationship between the man-made physical environment and health status of a population. The statistical technique of regression analysis was employed to show the degree of association and aspects of physical environment which accounted for the greater variation in health status. Mortality, venereal disease, tuberculosis, hepatitis, meningitis, shigella/salmonella, hypertension and cardiac arrest/myocardial infarction were examined. The statistical techniques were used to measure association and variation, not necessarily cause and effect. Conclusions drawn show that the association still exists in the decade of the 1970's and that it can be successfully monitored with the methodology of remote sensing
Functional Intimate Association Analysis: A Doctrinal Shift To Save the Roberts Framework
In Roberts v. U.S. Jaycees, the Supreme Court recognized intimate association as one of the two distinct senses of the freedom of association. In doing so, the Court identified two essential functions that justify constitutional protection for the relationships that provide them: intimate relationships cultivate and transmit shared ideals and beliefs, and they provide opportunities for emotional enrichment and self-identification by facilitating the creation of close bonds among members. Then, recognizing that familial relationships often exemplify these functions, the Court identified four aspects of family relationships that would help distinguish intimate from nonintimate associations: size, purpose, selectivity, and seclusion from others. Despite the secondary role of these aspects, subsequent decisions have focused solely on these four characteristics without even mentioning the justifications that originally supported constitutional protection. This factor-based analysis has resulted in unpredictable and inconsistent decisions that threaten to undermine the legitimacy of the entire Roberts framework. Drawing from the original functional justifications, this Note argues that courts must abandon their sole reliance on the Roberts factors and instead adopt a functional analysis that properly appreciates the right’s underlying values and ensures that groups reflecting those values are consistently protected
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