1,444 research outputs found
Imaging plant germline differentiation within Arabidopsis flowers by light sheet microscopy
In higher plants, germline differentiation occurs during a relatively short period within developing flowers. Understanding of the mechanisms that govern germline differentiation lags behind other plant developmental processes. This is largely because the germline is restricted to relatively few cells buried deep within floral tissues, which makes them difficult to study. To overcome this limitation, we have developed a methodology for live imaging of the germ cell lineage within floral organs of Arabidopsis using light sheet fluorescence microscopy. We have established reporter lines, cultivation conditions, and imaging protocols for high-resolution microscopy of developing flowers continuously for up to several days. We used multiview imagining to reconstruct a three-dimensional model of a flower at subcellular resolution. We demonstrate the power of this approach by capturing male and female meiosis, asymmetric pollen division, movement of meiotic chromosomes, and unusual restitution mitosis in tapetum cells. This method will enable new avenues of research into plant sexual reproduction.Web of Science9art. no. e5254
Forward Vehicle Collision Warning Based on Quick Camera Calibration
Forward Vehicle Collision Warning (FCW) is one of the most important
functions for autonomous vehicles. In this procedure, vehicle detection and
distance measurement are core components, requiring accurate localization and
estimation. In this paper, we propose a simple but efficient forward vehicle
collision warning framework by aggregating monocular distance measurement and
precise vehicle detection. In order to obtain forward vehicle distance, a quick
camera calibration method which only needs three physical points to calibrate
related camera parameters is utilized. As for the forward vehicle detection, a
multi-scale detection algorithm that regards the result of calibration as
distance priori is proposed to improve the precision. Intensive experiments are
conducted in our established real scene dataset and the results have
demonstrated the effectiveness of the proposed framework
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Global morphogenetic flow is accurately predicted by the spatial distribution of myosin motors.
During embryogenesis tissue layers undergo morphogenetic flow rearranging and folding into specific shapes. While developmental biology has identified key genes and local cellular processes, global coordination of tissue remodeling at the organ scale remains unclear. Here, we combine in toto light-sheet microscopy of the Drosophila embryo with quantitative analysis and physical modeling to relate cellular flow with the patterns of force generation during the gastrulation process. We find that the complex spatio-temporal flow pattern can be predicted from the measured meso-scale myosin density and anisotropy using a simple, effective viscous model of the tissue, achieving close to 90% accuracy with one time dependent and two constant parameters. Our analysis uncovers the importance of a) spatial modulation of myosin distribution on the scale of the embryo and b) the non-locality of its effect due to mechanical interaction of cells, demonstrating the need for the global perspective in the study of morphogenetic flow
The Problem of Integrating Ethics into IS Practice
In this paper we discuss a number of implications which follow from the way that the information systems discipline has developed, largely separately, from computer ethics. These include the tendency of quantitative IS studies on ethics to focus on ethical decision making as the most significant activity in the business of behaving morally meaning that other aspects of moral behaviour are overlooked. A second, significant, implication is the difficulty of integrating ethical practice into IS development. This is manifest initially in terms of IS education but later in relation to the development, and use, of IS in the workplace. Focusing on information systems development, we discuss practice, focusing on ethics and IS practice especially rationalistic approach to decision making, the support that conventional development methodologies offer the moral agent followed by learning to practice or the business of integrating ethics into IS education and how to turn moral decision making into teachable ethical constructs. We conclude by offering some suggestions for future directions
To Compress or Not to Compress -- Self-Supervised Learning and Information Theory: A Review
Deep neural networks have demonstrated remarkable performance in supervised
learning tasks but require large amounts of labeled data. Self-supervised
learning offers an alternative paradigm, enabling the model to learn from data
without explicit labels. Information theory has been instrumental in
understanding and optimizing deep neural networks. Specifically, the
information bottleneck principle has been applied to optimize the trade-off
between compression and relevant information preservation in supervised
settings. However, the optimal information objective in self-supervised
learning remains unclear. In this paper, we review various approaches to
self-supervised learning from an information-theoretic standpoint and present a
unified framework that formalizes the \textit{self-supervised
information-theoretic learning problem}. We integrate existing research into a
coherent framework, examine recent self-supervised methods, and identify
research opportunities and challenges. Moreover, we discuss empirical
measurement of information-theoretic quantities and their estimators. This
paper offers a comprehensive review of the intersection between information
theory, self-supervised learning, and deep neural networks
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