Dependent Hazards in Multivariate Survival Problems

A new class of bivariate survival distributions is constructed from a given family of survival distributions. The properties of these distributions are analyzed. It is shown that the same bivariate survival function can be derived using two radically different concepts: one involves transformation of the well-known bivariate survival function; the other involves correlated stochastic hazards. The new conditions that guarantee negative associations of life spans are derived. An exponential representation of the survival function for two related individuals is derived in terms of the conditional distribution of the stochastic hazards among survivors. Versions of the multivariate correlated gamma-frailty model are investigated.correlated hazards bivariate frailty, bivariate survival, mortality models

Synthesis of random parameter identification algorithms and estimates of current vessel motion parameters

The paper considers the task of synthesis of algorithms for identifying random parameters of a vessel, such as attached masses, moment of inertia, and estimating the current parameters of the vessel's motion from real-time measurements of onboard sensors. The task of the synthesis of algorithms for identifying random parameters of the vessel and evaluating the characteristics of the vessel’s movement is to determine (evaluate) the current parameters (attached masses, moment of inertia) and the characteristics of the vessel’s motion (position vector, speed) from the measurements of the vessel’s motion, angular position and angular velocity of the vessel rotation)

Multistate models of postpartum infecundity, fecundability and sterility by age and parity: Methodological issues

How do hidden physiological processes influence estimates of fecundability and sterility? Does unobserved heterogeneity play a role in these estimates? To address these questions mathematical models of the reproductive process are needed. It is not well known how to evaluate characteristics of reproductive models based on observed reproductive history data, and such models may not be identifiable without ancillary information. However, little is known about how to introduce ancillary information into reproductive models. Furthermore, even if such information was involved, the use of standard software packages for maximization of the likelihood function is often not feasible, because the function cannot be represented in an explicit parametric form. In this paper we propose an approach which represents the likelihood function in a form useful for further analysis. This approach is based on multistate models of the basic physiological processes that influence reproductive outcomes, and it is suitable in applications where ancillary information is given in the form of hazard rates. As an alternative, a competing risks model with incomplete information is discussed.Reproductive history models, Unobserved heterogeneity, Fertility Submitted by C.M. Suchindran,

Cloud-based evaluation of anatomical structure segmentation and landmark detection algorithms ::VISCERAL anatomy benchmarks

Variations in the shape and appearance of anatomical structures in medical images are often relevant radiological signs of disease. Automatic tools can help automate parts of this manual process. A cloud-based evaluation framework is presented in this paper including results of benchmarking current state-of-the-art medical imaging algorithms for anatomical structure segmentation and landmark detection: the VISCERAL Anatomy benchmarks. The algorithms are implemented in virtual machines in the cloud where participants can only access the training data and can be run privately by the benchmark administrators to objectively compare their performance in an unseen common test set. Overall, 120 computed tomography and magnetic resonance patient volumes were manually annotated to create a standard Gold Corpus containing a total of 1295 structures and 1760 landmarks. Ten participants contributed with automatic algorithms for the organ segmentation task, and three for the landmark localization task. Different algorithms obtained the best scores in the four available imaging modalities and for subsets of anatomical structures. The annotation framework, resulting data set, evaluation setup, results and performance analysis from the three VISCERAL Anatomy benchmarks are presented in this article. Both the VISCERAL data set and Silver Corpus generated with the fusion of the participant algorithms on a larger set of non-manually-annotated medical images are available to the research community

Subjective Distance Estimates and Sense of Agency in Robotic Wheelchair Control

Sense of agency (SoA) refers to an individual’s awareness of their own actions. SoA studies seek to find objective indicators for the feeling of agency. These indicators, being related to the feeling of control, have practical application in vehicle design. However, they have not been investigated for actions related to the agent’s body movement inherent to steering a vehicle. In our study, participants operated a robotic wheelchair under three conditions: active control by a participant, direct control by the experimenter and remote control by the experimenter. In each trial, a participant drove the wheelchair until a sound signal occurred, after which they stopped the wheelchair and estimated the travelled distance. The subjective estimates were significantly greater when participants operated the wheelchair by themselves. This result contrasts with observations under static settings in previous studies. In an additional study on the electroencephalographic response to a sound presented at a random time after movement onset, the observed latencies in the N1 component implied that participants might have a higher sense of control when they drove the wheelchair. The proposed methodology might become useful to indirectly assess the degree of operator control of a vehicle, primarily in the field of rehabilitation technologies

Subjective Distance Estimates and Sense of Agency in Robotic Wheelchair Control

Sense of agency (SoA) refers to an individual’s awareness of their own actions. SoA studies seek to find objective indicators for the feeling of agency. These indicators, being related to the feeling of control, have practical application in vehicle design. However, they have not been investigated for actions related to the agent’s body movement inherent to steering a vehicle. In our study, participants operated a robotic wheelchair under three conditions: active control by a participant, direct control by the experimenter and remote control by the experimenter. In each trial, a participant drove the wheelchair until a sound signal occurred, after which they stopped the wheelchair and estimated the travelled distance. The subjective estimates were significantly greater when participants operated the wheelchair by themselves. This result contrasts with observations under static settings in previous studies. In an additional study on the electroencephalographic response to a sound presented at a random time after movement onset, the observed latencies in the N1 component implied that participants might have a higher sense of control when they drove the wheelchair. The proposed methodology might become useful to indirectly assess the degree of operator control of a vehicle, primarily in the field of rehabilitation technologies

Universat-SOCRAT multi-satellite project to study TLEs and TGFs

Abstract We present concept of a new multi-satellite Universat-SOCRAT project aimed to study transient phenomena in the upper atmosphere such as transient luminous events (TLEs) and terrestrial gamma-ray flashes (TGFs). It is a new space project of Lomonosov Moscow State University based on the use of a few satellites in the near-Earth orbit for real-time monitoring of radiation environment, natural (asteroids, meteoroids) and artificial (space debris) potentially dangerous objects, electromagnetic transients including cosmic gamma-ray bursts, terrestrial gamma-ray flashes, and optical and ultraviolet bursts in the Earth’s atmosphere.Study of TLEs and TGFs remains an important and demanding task despite of a multitude of recently acquired data for these phenomena. This might be explained by the absence of comprehensive theoretical understanding of physical nature of high-energy processes in the Earth’s atmosphere. Multi-wavelength synchronous observations with moderate accuracy of localization of TGF and TLE events are necessary to gain an insight of physics governing these high-energy processes in the Earth’s atmosphere. In the article, we present results of TLE observations in space experiments of Moscow State University and discuss advanced instruments for optical observations of TLEs, as well as gamma-ray burst monitor and tracking gamma spectrometer for TGFs observations

Characterization and comparative analysis of the Escherichia marmotae M-12 isolate from bank vole (Myodes glareolus)

Abstract The Escherichia marmotae is a bacterium of the Enterobacterales order, which was first isolated from the Himalayan marmot (Marmota himalayana). Recently E. marmotae has been shown to cause severe infections in humans. Wild animals were suggested to be a natural reservoir of this bacterium. The present study describes the first case of E. marmotae isolation from an apparently healthy wild bank vole (Myodes glareolus). Phenotype, as well as genotype-based techniques, were applied to characterize E. marmotae M-12 isolate. E. marmotae M-12 had the capsule-positive phenotype, high adhesion to human erythrocytes and HEp-2 cells as well as a low invasion into HEp-2 cells. E. marmotae M-12 was avirulent in mice. The phylogenomic analyses of E. marmotae showed dispersed phylogenetic structure among isolates of different origins. Virulome analysis of M-12 isolate revealed the presence of the following factors: siderophores, heme uptake systems, capsule synthesis, curli and type I fimbriae, flagella proteins, OmpA porin, etc. Comparative virulome analysis among available E. marmotae genomes revealed the presence of capsule K1 genes mostly in pathogenic isolates and OmpA porin presence among all strains. We assume that the K1 capsule and OmpA porin play a key role in the virulence of E. marmotae. Pathogenesis of the latter might be similar to extraintestinal pathogenic E. coli