14 research outputs found
Analysis of Conditional Randomisation and Permutation schemes with application to conditional independence testing
We study properties of two resampling scenarios: Conditional Randomisation
and Conditional Permutation scheme which are relevant for conditional
independence testing of discrete random variables and given random
variable . Namely, we investigate asymptotic behaviour of estimates of a
vector of probabilities in such settings, establish their asymptotic normality
and ordering between asymptotic covariance matrices. The results are used to
derive asymptotic distributions of empirical Conditional Mutual Information in
these set-ups. Somewhat unexpectedly, the distributions coincide for the two
scenarios, despite differences in asymptotic distribution of estimates of
probabilities. We also prove validity of permutation p-values for Conditional
Permutation scheme. The above results justify consideration of conditional
independence tests based on re-sampled p-values and on asymptotic chi square
distribution with adjusted number of degrees of freedom. We show in numerical
experiments that when the ratio of the sample size to the number of possible
values of the triple exceeds 0.5, the test based on the asymptotic distribution
with the adjustment made on limited number of permutations is a viable
alternative to the exact test for both Conditional Permutation and Conditional
Randomisation scenarios. Moreover, there is no significant difference between
performance of exact tests for Conditional Permutation and Randomisation
scheme, the latter requiring knowledge of conditional distribution of given
, and the same conclusion is true for both adaptive tests.Comment: 28 page
Non-invasive imaging techniques in patients with coronary chronic total occlusions: A key for successful diagnosis, revascularization, and post-intervention outcomes
Coronary chronic total occlusions (CTOs) are a common finding on coronary angiograms of patientswith coronary artery disease, with an incidence ranging from 15% to 25%. Despite this high incidence,the proper treatment strategy in those patients often remains unclear. There are some observational studiessuggesting that successful revascularization of a CTO can reduce angina symptoms, improve qualityof life, improve the left ventricular ejection fraction, and lower mortality. However, not all patients willbenefit from revascularization. Pre-procedural assessment of left ventricular function, ischemic burden,and viability seems to be crucial for a good outcome of the revascularization. The aim of this review isto compare currently available non-invasive imaging modalities with regard to utility in evaluation ofpatients with CTOs
Analysis of Information-Based Nonparametric Variable Selection Criteria
We consider a nonparametric Generative Tree Model and discuss a problem of selecting active predictors for the response in such scenario. We investigated two popular information-based selection criteria: Conditional Infomax Feature Extraction (CIFE) and Joint Mutual information (JMI), which are both derived as approximations of Conditional Mutual Information (CMI) criterion. We show that both criteria CIFE and JMI may exhibit different behavior from CMI, resulting in different orders in which predictors are chosen in variable selection process. Explicit formulae for CMI and its two approximations in the generative tree model are obtained. As a byproduct, we establish expressions for an entropy of a multivariate gaussian mixture and its mutual information with mixing distribution
Training Motivation Questionnaire
Artykuł prezentuje „Kwestionariusz motywacji do podejmowania szkoleń”, pozwalający na diagnozę trzech typów motywacji: wewnętrznej, zewnętrznej i amotywacji, definiowanych zgodnie z teorią autodeterminacji Ryana i Deciego. Wyniki konfirmacyjnej
analizy czynnikowej na próbie 155 pracowników potwierdziły trafność modelu hierarchicznego, ujmującego trzy wymiary motywacji do podejmowania szkoleń wraz z sześcioma podwymiarami. Poszczególne typy motywacji wykazują przewidywane związki z intencją i planem podejmowania szkoleń, co potwierdza trafność metody. Wskaźniki rzetelności skal pozwalają na ich wykorzystywanie w badaniach naukowych i analizie wyników grupowych, na przykład w analizie potrzeb szkoleniowych, działaniach doradczych.The “Training Motivation Questionnaire” presented in this article makes possible the measuring of three types of motivation—intrinsic, extrinsic, and amotivation, as defined in Ryan and Deci’s theory of self–determination. The results of confirmatory factor analysis on a sample of 155 employees prove the accuracy of the hierarchical model. This model consists of three dimensions of motivation to undertake training together with six subscales. Each type of motivation reveals relationships with the intention and plan to train. This affirms the validity of this method. Scale reliability indicators allow application in scientific research as well as in group result analyses—e.g., training needs analysis and consultancy
Incidence of oat scab in 2013 and pathogenicity of Fusarium sporotrichioides Sherb. to selected cultivars
W 2013 roku na polach Hodowli Roślin Strzelce, Sp. z o.o., grupa IHAR określono udział wiech z objawami fuzariozy dla 12 odmian owsa. W laboratorium przeprowadzono analizę mykologiczną ziarniaków i plew pochodzących z wiech z objawami chorobowymi z wykorzystaniem pożywki mineralnej. Procent wiech z objawami fuzariozy wahał się od 0,25% do 2,0%. Za główną przyczynę fuzariozy wiech owsa uznano gatunki Fusarium culmorum i F. poae. Ponadto z porażonych ziarniaków uzyskiwano gatunki F. sporotrichioides i F. oxysporum. Badania szkodliwości F. sporotrichioides dla owsa przeprowadzono w 2013 roku na polach doświadczalnych w okolicach Zamościa, na podstawie ścisłego doświadczenia polowego ze sztucznym zakażaniem wiech w fazie kwitnienia. Materiał infekcyjny stanowiła zawiesina zarodników F. sporotrichioides nr 88 o zagęszczeniu 5 × 105 × 1 ml-1. Szkodliwość F. sporotrichioides dla analizowanych odmian owsa określano na podstawie ubytku liczby ziarniaków w wiesze, plonu ziarna z 40 wiech (4×10 wiech) oraz masy 1000 ziaren. Ubytek liczby ziarniaków w wiesze, w wyniku sztucznego zakażania przez F. sporotrichioides wynosił od 0,5% (Arden) do 75,1% (Contender). W przypadku odmiany Arden nie zanotowano ubytku plonu ziarna w wyniku inokulacji wiech przez F. sporotrichioides, zaś u pozostałych odmian redukcja plonu ziarna wynosiła od 24,0% (Komfort) do 79,5% (Contender). Natomiast obniżka MTZ wynosiła od 0,1% (Arden) do 22,6% (Flämingsgold).The incidence of panicles with scab symptoms was assessed in 12 oat cultivars in the fields of Strzelce Plant Breeding Company IHAR group in 2013. The mycological analysis of grain and chaff separated from panicles with disease symptoms was made in the laboratory using a mineral medium. The percentage of panicles with scab symptoms ranged from 0.25% to 2.0%. The species Fusarium culmorum and F. poae were the main causal agents of Fusarium oat scab. Fusarium sporotrichioides and F. oxysporum were also isolated from infected kernels. A study of pathogenicity of F. sporotrichioides to oat was carried out in the experimental plots in Zamość region (southeastern Poland). Oat panicles were inoculated during flowering. The infectious material was a suspension of conidia of F. sporotrichioides no. 88 with a density of 5 × 105 spores per 1 ml. The pathogenicity of F. sporotrichioides to analyzed oat genotypes was determined on the basis of the reduction in the number of kernels per panicle, kernels yield from 40 panicles (4 × 10 panicles) and 1000 kernels weight. The reduction in the number of kernels in panicle as a result of inoculation of panicles with F. sporotrichioides ranged from 0.5% (Arden) to 75.1% (Contender). In the case of cv. Arden the reduction in kernels yield was not detected and in the case of other cultivars it ranged from 24.0% (Komfort) to 79.5% (Contender). The reduction in 1000 kernels weight ranged from 0.1% (Arden) to 22.6% (Flämingsgold)
Reaction of Oat Genotypes to Fusarium equiseti (Corda) Sacc. Infection and Mycotoxin Concentrations in Grain
Fusarium head blight and the contamination of cereals with toxic fungal metabolites are particularly important problems in global agriculture. The increasingly frequent isolation of F. equiseti from cereal grain and the sparse information in the literature on the harmfulness of this fungus to oat encouraged us to conduct the present research. The aim of the study was to determine the susceptibility of oat genotypes to panicle infection by F. equiseti and mycotoxin content in the grain. Field experiments involving 10 oat genotypes were conducted over three years (2015–2017). Oat panicles were inoculated with a conidial suspension of F. equiseti, which reduced the kernels yield by 38.34%, the number of kernels per panicle by 31.16% and 1000 kernels weight by 12.66%. F. equiseti accumulated type A trichothecenes (T-2 and HT-2 toxins, scirpentriol, diacetoxyscirpenol, T-2 triol, T-2 tetraol) and type B trichothecenes (deoxynivalenol, 3Ac-DON, 15Ac-DON, nivalenol, fusarenone X) in kernels at an average level of 0.0616 and 0.2035 mg·kg−1, respectively. The highest susceptibility to scabs caused by F. equiseti was found for genotype POB 4901/10, whereas cv. Elegant exhibited the highest resistance to F. equiseti in terms of yield reduction after inoculation
The effect of artificial inoculation of oat with Fusarium equiseti (Corda) Sacc. on the yield and mycotoxin content in the grain
Szkodliwość szczepu F. equiseti nr 20 wobec 15 genotypów owsa określono na podstawie ścisłego doświadczenia polowego ze sztucznym zakażaniem wiech. Badania przeprowadzono w 2014 roku, na polu doświadczalnym w południowo-wschodniej Polsce. Materiał infekcyjny stanowiła zawiesina konidiów F. equiseti. Średnia obniżka liczby ziarniaków w wiesze, w porównaniu do kontroli wynosiła 45,7% (od 15,8 do 66,7%), natomiast redukcja plonu ziarna wynosiła 47,7% (od 20,3 do 69,3%). Obniżka masy 1000 ziaren u badanych genotypów owsa wahała się od 0,5% do 22,8%, średnio 7,3%. W próbach ziarna wszystkich genotypów owsa stwierdzono obecność związków trichotecenowych z grupy A: T-2 toksyny od 0,001 do 0,044 mg·kg-1, HT- 2 toksyny od 0,001 do 0,081 mg·kg-1, scirpentriolu (STO) od 0,002 do 0,056 mg·kg-1,T-2 tetraolu od 0,001 do 0,152 mg·kg-1. Obecność diacetoksyscirpenolu (DAS) i T-2 triolu, stwierdzono u 14 analizowanych genotypów owsa. Stężenie tych metabolitów wynosiło odpowiednio od 0,001 do 0,005 mg·kg-1 i od 0,001 do 0,008 mg·kg-1. Ponadto w próbach ziarna wszystkich genotypów owsa, pochodzących z wiech inokulowanych F. equiseti oznaczono 3-Ac DON (0,023–0,026 mg·kg-1), w przypadku 14 genotypów stwierdzono obecność DON (0,016–0,233 mg·kg-1), zaś NIV był obecny w próbach 13 genotypów owsa, w stężeniu od 0,022 do 0,218 mg·kg-1.The field experiment with artificial infection of panicles of 15 oat genotypes was performed in 2014, in southeastern Poland. Panicles were inoculated with conidial suspension of Fusarium equiseti no. 20. The mean reduction in the number of kernels per panicle was 45.7% (from 15.8 to 66.7%), in kernel yield — 47.7% (from 20.3 to 69.3%), and 1000 kernel weight — 7.3% (from 0.5 to 22.8%). Trichothecenes of group A and B were detected in oat kernels. The concentration of T-2 toxin ranged from 0.001 to 0.044 mg·kg-1, HT- 2 toxin from 0.001 to 0.081 mg·kg-1, scirpentriol (STO) from 0.002 to 0.056 mg·kg-1, T-2 tetraol from 0.001 to 0.152 mg·kg-1. In kernels of 14 oat genotypes diacetoxyscirpenol (DAS) and T-2 triol were found and concentration of these metabolites ranged from 0.001 to 0.005 mg·kg-1 and from 0.001 to 0.008 mg·kg-1, respectively. Additionally in the infected kernels the following trichothecenes of group B were detected: DON (0.000-0.233 mg·kg-1), 3-Ac - DON (0.023-0.026mg·kg-1), and NIV (0.000-0.218 mg·kg-1)
Reaction of Oat Genotypes to <i>Fusarium equiseti</i> (Corda) Sacc. Infection and Mycotoxin Concentrations in Grain
Fusarium head blight and the contamination of cereals with toxic fungal metabolites are particularly important problems in global agriculture. The increasingly frequent isolation of F. equiseti from cereal grain and the sparse information in the literature on the harmfulness of this fungus to oat encouraged us to conduct the present research. The aim of the study was to determine the susceptibility of oat genotypes to panicle infection by F. equiseti and mycotoxin content in the grain. Field experiments involving 10 oat genotypes were conducted over three years (2015–2017). Oat panicles were inoculated with a conidial suspension of F. equiseti, which reduced the kernels yield by 38.34%, the number of kernels per panicle by 31.16% and 1000 kernels weight by 12.66%. F. equiseti accumulated type A trichothecenes (T-2 and HT-2 toxins, scirpentriol, diacetoxyscirpenol, T-2 triol, T-2 tetraol) and type B trichothecenes (deoxynivalenol, 3Ac-DON, 15Ac-DON, nivalenol, fusarenone X) in kernels at an average level of 0.0616 and 0.2035 mg·kg−1, respectively. The highest susceptibility to scabs caused by F. equiseti was found for genotype POB 4901/10, whereas cv. Elegant exhibited the highest resistance to F. equiseti in terms of yield reduction after inoculation