7,503 research outputs found
Evidence functions: a compositional approach to information
The discrete case of Bayesâ formula is considered the paradigm of information acquisition. Prior and posterior probability functions, as well as likelihood functions, called evidence functions, are compositions following the Aitchison geometry of the simplex, and have thus vector character. Bayesâ formula becomes a vector addition. The Aitchison norm of an evidence function is introduced as a scalar measurement of information. A fictitious fire scenario serves as illustration. Two different inspections of affected houses are considered. Two questions are addressed: (a) which is the information provided by the outcomes of inspections, and (b) which is the most informative inspection.Peer Reviewe
Cellulosic materials as natural fillers in starch-containing matrix-based films: a review
In this work, the different cellulosic materials, namely cellulose and lignin are analyzed. In addition, the starch-containing matrices (isolated starch and flour) reinforced with cellulosic materials to be used in packaging applications are described. Many efforts have been exerted to develop biopackaging based on renewable polymers, since these could reduce the environmental impact caused by petrochemical resources. Special attention has had the starch as macromolecule for forming biodegradable packaging. For these reasons, shall also be subject of this review the effect of each type of cellulosic material on the starch-containing matrix-based thermoplastic materials. In this manner, this review contains a description of films based on starch-containing matrices and biocomposites, and then has a review of cellulosic material-based fillers. In the same way, this review contains an analysis of the works carried out on starch-containing matrices reinforced with cellulose and lignin. Finally, the manufacturing processes of starch/cellulose composites are provided as well as the conclusions and the outlook for future works.Fil: GutiĂ©rrez Carmona, Tomy JosĂ©. Universidad Central de Venezuela; Venezuela. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico Conicet - Mar del Plata. Instituto de Investigaciones en Ciencia y TecnologĂa de Materiales. Universidad Nacional de Mar del Plata. Facultad de IngenierĂa. Instituto de Investigaciones en Ciencia y TecnologĂa de Materiales; ArgentinaFil: Alvarez, Vera Alejandra. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico Conicet - Mar del Plata. Instituto de Investigaciones en Ciencia y TecnologĂa de Materiales. Universidad Nacional de Mar del Plata. Facultad de IngenierĂa. Instituto de Investigaciones en Ciencia y TecnologĂa de Materiales; Argentin
Evidence functions: a compositional approach to information
The discrete case of Bayesâ formula is considered the paradigm of information acquisition. Prior and posterior probability functions, as well as likelihood functions, called evidence functions, are compositions following the Aitchison geometry of the simplex, and have thus vector character. Bayesâ formula becomes a vector addition. The Aitchison norm of an evidence function is introduced as a scalar measurement of information. A fictitious fire scenario serves as illustration. Two different inspections of affected houses are considered. Two questions are addressed: (a) which is the information provided by the outcomes of inspections, and (b) which is the most informative inspection.Peer ReviewedPostprint (author's final draft
Evaluation of the police operational tactical procedures for reducing officer injuries resulting from physical interventions in problematic arrests. The case of the Municipal Police of CĂĄdiz (Spain)
Objectives: This paper describes some operational tactical procedures (OTP) and discusses the results of a 14-year-long study, spanning the period 2003-2016, conducted by the Municipal Police of Cadiz, Spain, which comprised 3 time periods: 2003-2006, when the officers were trained in traditional policing procedures; 2007-2013, when the officers were taught an innovative set of OTP in the form of a basic set of self-defense and arrest mechanisms, different from the traditional policing procedures that rely on martial arts and combat sports; and finally 2014-2016, when the OTP training was discontinued. The aim of this study was to improve policing and reduce officer injuries resulting from interventions in controversial or violent situations, such as problematic arrests. Material and Methods: The study involved 162 police officers and commanders of the Municipal Police of Cadiz, who were in street duty for their first time. There were 8 females and 154 males aged 24-55 years. Three OTP stages are shown as examples. Results: Based on the analysis of "training hours" and "physical interventions in problematic arrests," the results were: 1) the number of sick leaves in the police was identical according to the number of arrests, and 2) data on sick leaves show remarkable differences among the 3 periods under analysis. Conclusions: The OTP-based training substantially reduced officer sick leaves. The overall reduction in sick leaves in the period 2007-2013 was observed that cannot be ascribed to a decrease in criminal acts, and hence in police physical interventions
A two-step log-linear procedure for graphical representation and inference of associations in cross-classified data for disease diagnosis
Biometrical sciences and disease diagnosis in particular, are often concerned
with the analysis of associations for cross-classified data, for which distance
association models give us a graphical interpretation for non-sparse matrices
with a low number of categories. In this framework, usually binary exploratory
and response variables are present, with analysis based on individual profiles
being of great interest. For saturated models, we show the usual linear relationship
for log-linear models is preserved in full dimension for the distance
association parameterization. This enables a two-step procedure to facilitate the
analysis and the interpretation of associations in terms of unfolding after the
overall and main effects are removed. The proposed procedure can deal with
cross-classified data for profiles by binary variables, and it is easy to implement
using traditional statistical software. For disease diagnosis, the problems of a
degenerate solution in the unfolding representation, and that of determining significant
differences between the profile locations are addressed. A hypothesis
test of independence based on odds ratio is considered. Furthermore, a procedure
is proposed to determine the causes of the significance of the test, avoiding
the problem of error propagation. The equivalence between a test for equality
of odds ratio pairs and the test for equality of location for two profiles in the
unfolding representation in the disease diagnosis is shown. The results have
been applied to a real example on the diagnosis of coronary disease, relating the
odds ratios with performance parameters of the diagnostic testERDF/Ministry of Economic
Transformation, Industry, knowledge and
Universities of AndalucĂa, Grant/Award
Number: B-CTS-184-UGR20MCIN/AEI/10.13039/501100011033 and
by âERDF A way of making Europeâ,Grant/Award Number:
PID2021-126095NB-100; Ministry of
Science and Innovation-State Research
Agency/10.13039/501100011033/SpainERDF A way of making Europeâ,
Grant/Award Number:
RTI2018-099723-B-I0
Is the accelerated expansion evidence of a forthcoming change of signature on the brane?
We show that regular changes of signature on brane-worlds in AdS bulks may
account for some types of the recently fashionable sudden singularities.
Therefore, the possibility that the Universe seems to approach a future sudden
singularity at an accelerated rate of expansion might simply be an indication
that our braneworld is about to change from Lorentzian to Euclidean signature.
Both the brane and the bulk remain fully regular everywhere. We present a model
in which the weak and strong energy conditions hold on the brane, in contrast
with the standard cosmologies leading to the analogous kinematical behaviour
(that is, with a diverging Hubble factor).Comment: 5 pages, 1 figure. Minor improvements in abstract and main text. New
title and new reference added. To be published in PR
Two-Loop Gluon Regge Trajectory from Lipatov's Effective Action
Lipatov's high-energy effective action is a useful tool for computations in
the Regge limit beyond leading order. Recently, a regularisation/subtraction
prescription has been proposed that allows to apply this formalism to calculate
next-to-leading order corrections in a consistent way. We illustrate this
procedure with the computation of the gluon Regge trajectory at two loops.Comment: 4 pages, 5 figures, Proceedings of the XX Workshop on Deep-Inelastic
Scattering and Related Subjects, 26-30 March, University of Bonn (2012
Dibujos de Farid Romero
_Ensayo de presentación de la obra plåstica de Farid Romero a cargo de José Luis Vera
Granger-Causality in the presence of structural breaks
The concept of Granger-Causality (GC) is widely used to draw inference concerning causality in applied economics. Stationary series are the term of reference used in GC testing, which is generally studied by means of a standard Dickey-Fuller test. We prove that, when the Data Generating Process (DGP) of the variables is either Broken-Trend Stationary (BTS) or Broken-Mean Stationary (BMS), correct inference can not be drawn from a standard Granger-Causality test and may identify inexistent causal relationships, even if the former variables are differenced. Asymptotic and finite-sample evidence in this sense is provided.
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