scholarly journals Updating Probabilities

2003 ◽  
Vol 19 ◽  
pp. 243-278 ◽  
Author(s):  
P. D. Grunwald ◽  
J. Y. Halpern

As examples such as the Monty Hall puzzle show, applying conditioning to update a probability distribution on a ``naive space'', which does not take into account the protocol used, can often lead to counterintuitive results. Here we examine why. A criterion known as CAR (``coarsening at random'') in the statistical literature characterizes when ``naive'' conditioning in a naive space works. We show that the CAR condition holds rather infrequently, and we provide a procedural characterization of it, by giving a randomized algorithm that generates all and only distributions for which CAR holds. This substantially extends previous characterizations of CAR. We also consider more generalized notions of update such as Jeffrey conditioning and minimizing relative entropy (MRE). We give a generalization of the CAR condition that characterizes when Jeffrey conditioning leads to appropriate answers, and show that there exist some very simple settings in which MRE essentially never gives the right results. This generalizes and interconnects previous results obtained in the literature on CAR and MRE.

2021 ◽  
Vol 9 (5) ◽  
pp. 1107
Author(s):  
Wonho Choi ◽  
Yoshihiro Yamaguchi ◽  
Ji-Young Park ◽  
Sang-Hyun Park ◽  
Hyeok-Won Lee ◽  
...  

Agrobacterium tumefaciens is a pathogen of various plants which transfers its own DNA (T-DNA) to the host plants. It is used for producing genetically modified plants with this ability. To control T-DNA transfer to the right place, toxin-antitoxin (TA) systems of A. tumefaciens were used to control the target site of transfer without any unintentional targeting. Here, we describe a toxin-antitoxin system, Atu0939 (mazE-at) and Atu0940 (mazF-at), in the chromosome of Agrobacterium tumefaciens. The toxin in the TA system has 33.3% identity and 45.5% similarity with MazF in Escherichia coli. The expression of MazF-at caused cell growth inhibition, while cells with MazF-at co-expressed with MazE-at grew normally. In vivo and in vitro assays revealed that MazF-at inhibited protein synthesis by decreasing the cellular mRNA stability. Moreover, the catalytic residue of MazF-at was determined to be the 24th glutamic acid using site-directed mutagenesis. From the results, we concluded that MazF-at is a type II toxin-antitoxin system and a ribosome-independent endoribonuclease. Here, we characterized a TA system in A. tumefaciens whose understanding might help to find its physiological function and to develop further applications.


2019 ◽  
Vol 34 (4) ◽  
pp. 419-437 ◽  
Author(s):  
Roberto Rocco ◽  
Luciana Royer ◽  
Fábio Mariz Gonçalves

1985 ◽  
Vol 5 (11) ◽  
pp. 2887-2893
Author(s):  
M Neitz ◽  
J Carbon

A functional centromere located on a small DNA restriction fragment from Saccharomyces cerevisiae was identified as CEN14 by integrating centromere-adjacent DNA plus the URA3 gene by homologous recombination into the yeast genome and then by localizing the URA3 gene to chromosome XIV by standard tetrad analysis. DNA sequence analysis revealed that CEN14 possesses sequences (elements I, II, and III) that are characteristic of other yeast centromeres. Mitotic and meiotic analyses indicated that the CEN14 function resides on a 259-base-pair (bp) RsaI-EcoRV restriction fragment, containing sequences that extend only 27 bp to the right of the element I to III region. In conjunction with previous findings on CEN3 and CEN11, these results indicate that the specific DNA sequences required in cis for yeast centromere function are contained within a region about 150 bp in length.


QJM ◽  
2021 ◽  
Vol 114 (Supplement_1) ◽  
Author(s):  
Rania Ali Maarouf ◽  
Ali Haggag Ali ◽  
Mahmoud Abdelatif Onsy

Abstract Background Despite the recent advances in liver imaging, the detection and characterization of small hepatic focal lesions is still a real challenge. Particularly in cancer patients where the characterization of a small HFL as thus the precise tumor staging is critical for optimal treatment planning. Aim of the Work To explore the effectiveness, and hence the clinical utility, of MRI detection and characterization of small focal hepatic lesions either only discovered on MRI or as a further work up of CT/US-indeterminate lesions. Patients and Methods We reviewed our database for individuals who underwent liver MR imaging between March 2018 and March 2019 for the evaluation of small hepatic lesions that were discovered for the first time or had been previously visualized on routinely performed CT and had been considered indeterminate. Results The present study included 44 patients of which 26 were males (59.1%) and 18 were females (40.9%). The age range of the study group was 19 to 77 years. The mean age for Malignant lesions was 51 years. The right lobe of liver was involved in 23 cases (52.3%), left lobe in 5 cases (11.4%) and both lobes in 16 cases (36.4%). There were 30 (68.18%) benign, 13 (29.54%) malignant lesions and 1 (2.3%) indeterminate, hemangiomas were predominant in benign lesions whereas hepatocellular carcinomas were predominant in malignant lesions. N'TRI could characterize 92% cases. Conclusion The diagnostic process of small hepatic focal lesions, either detection or characterization or both, continues to represent a challenge. Contrast-enhanced MR can accurately detect and characterize majority of small hepatic focal lesions.


2016 ◽  
Vol 2016 ◽  
pp. 1-11 ◽  
Author(s):  
Octavian Pastravanu ◽  
Mihaela-Hanako Matcovschi

The main purpose of this work is to show that the Perron-Frobenius eigenstructure of a positive linear system is involved not only in the characterization of long-term behavior (for which well-known results are available) but also in the characterization of short-term or transient behavior. We address the analysis of the short-term behavior by the help of the “(M,β)-stability” concept introduced in literature for general classes of dynamics. Our paper exploits this concept relative to Hölder vectorp-norms,1≤p≤∞, adequately weighted by scaling operators, focusing on positive linear systems. Given an asymptotically stable positive linear system, for each1≤p≤∞, we prove the existence of a scaling operator (built from the right and left Perron-Frobenius eigenvectors, with concrete expressions depending onp) that ensures the best possible values for the parametersMandβ, corresponding to an “ideal” short-term (transient) behavior. We provide results that cover both discrete- and continuous-time dynamics. Our analysis also captures the differences between the cases where the system dynamics is defined by matrices irreducible and reducible, respectively. The theoretical developments are applied to the practical study of the short-term behavior for two positive linear systems already discussed in literature by other authors.


Psihologija ◽  
2007 ◽  
Vol 40 (1) ◽  
pp. 5-35
Author(s):  
Aleksandar Kostic ◽  
Milena Bozic

In this study we investigate the constraints on probability distribution of grammatical forms within morphological paradigms of Serbian language, where paradigm is specified as a coherent set of elements with defined criteria for inclusion. Thus, for example, in Serbian all feminine nouns that end with the suffix "a" in their nominative singular form belong to the third declension, the declension being a paradigm. The notion of a paradigm could be extended to other criteria as well, hence, we can think of noun cases, irrespective of grammatical number and gender, or noun gender, irrespective of case and grammatical number, also as paradigms. We took the relative entropy as a measure of homogeneity of probability distribution within paradigms. The analysis was performed on 116 morphological paradigms of typical Serbian and for each paradigm the relative entropy has been calculated. The obtained results indicate that for most paradigms the relative entropy values fall within a range of 0.75 - 0.9. Nonhomogeneous distribution of relative entropy values allows for estimating the relative entropy of the morphological system as a whole. This value is 0.69 and can tentatively be taken as an index of stability of the morphological system.


Balcanica ◽  
2004 ◽  
pp. 51-70
Author(s):  
Ivan Jordovic

The Focus of this study is the standpoint of the play Sisyphus and critias the leader of the thirty towards the right of the stronger. this is a question of constant interest in scientific circles, since its answer can serve as the indicator of the influence this famous theory has had. this interest has been encouraged by the fact that critias? authorship of the play is questionable. however, the question of the author is not of primary importance for this article, because there are some arguments, among some well known ones, which were not considered and which Show that in this satire, regardless of the author and the purpose of this fragment, the right of the stronger is actually non-existant. the first argument to support this theory is that nomosphysis antithesis is nowhere explicitly mentioned although it is the crucial element of the right of the stronger. in addition there is no claim in the play that the exploitation of the strong by the week or by law accrued. the second argument is that despite the incapability of laws to prevent the secret injustice, they and their importance for the human society are depicted in a positive light. it should also be noted that, unlike callicles and glaucon, laws are created to stop the bad and not the good. the third argument is that the invention of religion is accepted as a positive achievement, which finally enables the overcoming of primeval times and lawlessness. the reflection of this argument is a positive characterization of the individual who invented the fear of gods. the fourth argument, which has not been taken into consideration so far is the way the supporters and opponents of lawlessness are described and marked as ????? and ?????? in the satire only physically strong are considered as strong as opposed to callicles, where they are also spiritually superior. intelectually superior in Sisyphus is the inventor of the fear of gods who is also in favor of law and order. the fact that the strong are described as kako? while the supporter of law are recognized as ?????? is also of great importance. in other words, this division re?ects strong influence of aristocratic set of values by which the ?????? are in every way superior to the ?????. some other indications Show that critias cannot be listed as a advocate of the right of the stronger regardless of our previous conclusion about the play. we need to bear in mind the fact that critias has only recently been linked with the theory of the right of the stronger. in the classical period there had been non attempt to explain his ruthless politics in Athens 404/403 BC by Means of the right of the stronger. what is more, no indication that he supported this theory were found. unlike xenophon and philostratus, it is very likely that Plato and Aristotle were mild to critias Due to his family ties with Plato and his friendship with Socrates. however, all the four of them would have stated that critias was an upholder of the right of the stronger if he had actually been that. that way Socrates would have been completely acquitted of the responsibility for the crimes critias had committed, because of the possible assertion that critias was misled by this theory and succumbed to the negative influence of the sophistic teachings. based on these arguments we can conclude that there is no trace of the right of the stronger in the play Sisyphus and that critias did not support this theory. this satirical play and critias were Most probably under a great influence of aristocratic beliefs, which were often scientifically misinterpreted as the reflection of the right of the stronger.


2021 ◽  
Vol 2021 (3) ◽  
Author(s):  
Mohamed Nagy ◽  
Hatem Hosny ◽  
Amr El Sawy ◽  
Ahmed Mahgoub ◽  
Magdi H Yacoub

Background: There is a pressing need to improve early and long-term results of the Mustard operation. A modification of the operation was introduced at the Aswan Heart Centre for this purpose which relies on creating new functional atria rather than the two rigid channels in the classical Mustard operation.Objectives: To evaluate the morphology and function of the neo-atria, shortly after modified mustard operation for a ‘neglected’ patient with TGA, VSD and severe pulmonary hypertension.Methods: A 6-year-old with neglected TGA, VSD and pulmonary hypertension presented with severe cyanosis, clubbing and haemoconcentration (Hb 22 g/dL), underwent the modified Aswan-Mustard operation (MAM) with rapid smooth postoperative recovery. Repeated 2D echograms and multi-slice CT scans, followed by 3D segmentation, were performed after the operation. The size, shape, and morphology of the neo-atria were measured and measurements of the patterns of instantaneous filling and emptying of the right and left ventricles were quantified.Results: The neo-systemic venous atrium consisted of three components with a combined volume of 78 mL/m2, all of which contributed to the reservoir, conduit, and importantly contractile function of the neo-atrium. The pulmonary venous atrium consisted of two components with a combined volume of 66 mL/m2. These measurements were made at atrial end diastole. The volumes of the systemic venous and the pulmonary venous diminished to 51 and 54 mL/m2, respectively, at the end atrial systole - indicating relatively preserved contractile functions.


Zootaxa ◽  
2017 ◽  
Vol 4258 (6) ◽  
pp. 581 ◽  
Author(s):  
FRANCIANE CEDROLA ◽  
ROBERTO JÚNIO PEDROSO DIAS ◽  
ISABEL MARTINELE ◽  
MARTA D’AGOSTO

To date the genus Diploplastron comprised only one species of ophryoscolecid ciliate, Diploplastron affine, which is characterized by having two retractable ciliary zones in the anterior end of the body, two slender and juxtaposed skeletal plates on the right side, a rod shape macronucleus, and two contractile vacuoles. During study on the characterization of rumen ciliate community composition in Brazilian domestic sheep, we observed ciliates with atypical morphology but with diagnostic features of genus Diploplastron. This study describes Diploplastron dehorityi, a new species of ophryoscolecid ciliate, that differs from D. affine, primarily, in the morphology of skeletal plates, morphology of nuclear apparatus and body shape. In addition to the similarities between the new species and congener species, D. dehorityi has some morphological similarities to species of genus Eremoplastron.


2018 ◽  
Vol 8 (1) ◽  
Author(s):  
A. Soltani ◽  
J. Lahti ◽  
K. Järvelä ◽  
S. Curtze ◽  
J. Laurikka ◽  
...  

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