58 research outputs found
This New Ocean: A History of Project Mercury
When Congress created the National Aeronautics and Space Administration (NASA) in 1958, it charged NASA with the responsibility "to contribute materially to . . . the expansion of human knowledge of phenomena in the atmosphere and space" and "provide for the widest practicable and appropriate dissemination of information concerning its activities and the results thereof." NASA wisely interpreted this mandate to include responsibility for documenting the epochal progress of which it is the focus. The result has been the development of a historical program by NASA as unprecedented as the task of extending man's mobility beyond his planet. This volume is not only NASA's accounting of its obligation to disseminate information to our current generation of Americans. It also fulfills, as do all of NASA's future-oriented scientific-technological activities, the further obligation to document the present as the heritage of the future. The wide-ranging NASA history program includes chronicles of day-to-day space activities; specialized studies of particular fields within space science and technology; accounts of NASA's efforts in organization and management, where its innovations, while less known to the public than its more spectacular space shots, have also been of great significance; narratives of the growth and expansion of the space centers throughout the country, which represent in microcosm many aspects of NASA's total effort; program histories, tracing the successes- and failures- of the various projects that mark man's progress into the Space Age; and a history of NASA itself, incorporating in general terms the major problems and challenges, and the responses thereto, of our entire civilian space effort. The volume presented here is a program history, the first in a series telling of NASA's pioneering steps into the Space Age. It deals with the first American manned-spaceflight program: Project Mercury. Although some academicians might protest that this is "official" history, it is official only in the fact that it has been prepared and published with the support and cooperation of NASA. It is not "official" history in the sense of presenting a point of view supposedly that of NASA officialdom-if anyone could determine what the "point of view" of such a complex organism might be. Certainly, the authors were allowed to pursue their task with the fullest freedom and in accordance with the highest scholarly standards of the history profession
Assisted Probe Positioning for Ultrasound Guided Radiotherapy Using Image Sequence Classification
Effective transperineal ultrasound image guidance in prostate external beam
radiotherapy requires consistent alignment between probe and prostate at each
session during patient set-up. Probe placement and ultrasound image
inter-pretation are manual tasks contingent upon operator skill, leading to
interoperator uncertainties that degrade radiotherapy precision. We demonstrate
a method for ensuring accurate probe placement through joint classification of
images and probe position data. Using a multi-input multi-task algorithm,
spatial coordinate data from an optically tracked ultrasound probe is combined
with an image clas-sifier using a recurrent neural network to generate two sets
of predictions in real-time. The first set identifies relevant prostate anatomy
visible in the field of view using the classes: outside prostate, prostate
periphery, prostate centre. The second set recommends a probe angular
adjustment to achieve alignment between the probe and prostate centre with the
classes: move left, move right, stop. The algo-rithm was trained and tested on
9,743 clinical images from 61 treatment sessions across 32 patients. We
evaluated classification accuracy against class labels de-rived from three
experienced observers at 2/3 and 3/3 agreement thresholds. For images with
unanimous consensus between observers, anatomical classification accuracy was
97.2% and probe adjustment accuracy was 94.9%. The algorithm identified optimal
probe alignment within a mean (standard deviation) range of 3.7
(1.2) from angle labels with full observer consensus, comparable to
the 2.8 (2.6) mean interobserver range. We propose such an
algorithm could assist ra-diotherapy practitioners with limited experience of
ultrasound image interpreta-tion by providing effective real-time feedback
during patient set-up.Comment: Accepted to MICCAI 202
DeepReg: a deep learning toolkit for medical image registration
DeepReg (https://github.com/DeepRegNet/DeepReg) is a community-supported
open-source toolkit for research and education in medical image registration
using deep learning.Comment: Accepted in The Journal of Open Source Software (JOSS
DeepReg: a deep learning toolkit for medical image registration
Image fusion is a fundamental task in medical image analysis and computer-assisted intervention. Medical image registration, computational algorithms that align different images
together (Hill et al., 2001), has in recent years turned the research attention towards deep
learning. Indeed, the representation ability to learn from population data with deep neural
networks has opened new possibilities for improving registration generalisability by mitigating
difficulties in designing hand-engineered image features and similarity measures for many realworld clinical applications (Fu et al., 2020; Haskins et al., 2020). In addition, its fast inference can substantially accelerate registration execution for time-critical tasks.
DeepReg is a Python package using TensorFlow (Abadi et al., 2015) that implements multiple registration algorithms and a set of predefined dataset loaders, supporting both labelledand unlabelled data. DeepReg also provides command-line tool options that enable basic and
advanced functionalities for model training, prediction and image warping. These implementations, together with their documentation, tutorials and demos, aim to simplify workflows for prototyping and developing novel methodology, utilising latest development and accessing quality research advances. DeepReg is unit tested and a set of customised contributor
guidelines are provided to facilitate community contributions.
A submission to the MICCAI Educational Challenge has utilised the DeepReg code and demos
to explore the link between classical algorithms and deep-learning-based methods (Montana
Brown et al., 2020), while a recently published research work investigated temporal changes
in prostate cancer imaging, by using a longitudinal registration adapted from the DeepReg
code (Yang et al., 2020)
Quality standards for managing children and adolescents with bronchiectasis: an international consensus
The global burden of bronchiectasis in children and adolescents is being recognised increasingly. However, marked inequity exists between, and within, settings and countries for resources and standards of care afforded to children and adolescents with bronchiectasis compared with those with other chronic lung diseases. The European Respiratory Society (ERS) clinical practice guideline for the management of bronchiectasis in children and adolescents was published recently. Here we present an international consensus of quality standards of care for children and adolescents with bronchiectasis based upon this guideline. The panel used a standardised approach that included a Delphi process with 201 respondents from the parents and patients’ survey, and 299 physicians (across 54 countries) who care for children and adolescents with bronchiectasis. The seven quality standards of care statements developed by the panel address the current absence of quality standards for clinical care related to paediatric bronchiectasis. These internationally derived, clinician-, parent-and patient-informed, consensus-based quality standards statements can be used by parents and patients to access and advocate for quality care for their children and themselves, respectively. They can also be used by healthcare professionals to advocate for their patients, and by health services as a monitoring tool, to help optimise health outcomes.</p
The \u3cem\u3eChlamydomonas\u3c/em\u3e Genome Reveals the Evolution of Key Animal and Plant Functions
Chlamydomonas reinhardtii is a unicellular green alga whose lineage diverged from land plants over 1 billion years ago. It is a model system for studying chloroplast-based photosynthesis, as well as the structure, assembly, and function of eukaryotic flagella (cilia), which were inherited from the common ancestor of plants and animals, but lost in land plants. We sequenced the ∼120-megabase nuclear genome of Chlamydomonas and performed comparative phylogenomic analyses, identifying genes encoding uncharacterized proteins that are likely associated with the function and biogenesis of chloroplasts or eukaryotic flagella. Analyses of the Chlamydomonas genome advance our understanding of the ancestral eukaryotic cell, reveal previously unknown genes associated with photosynthetic and flagellar functions, and establish links between ciliopathy and the composition and function of flagella
Expression, tandem repeat copy number variation and stability of four macrosatellite arrays in the human genome
Finished Genome of the Fungal Wheat Pathogen Mycosphaerella graminicola Reveals Dispensome Structure, Chromosome Plasticity, and Stealth Pathogenesis.
The plant-pathogenic fungus Mycosphaerella graminicola (asexual stage: Septoria tritici) causes septoria tritici blotch, a disease that greatly reduces the yield and quality of wheat. This disease is economically important in most wheat-growing areas worldwide and threatens global food production. Control of the disease has been hampered by a limited understanding of the genetic and biochemical bases of pathogenicity, including mechanisms of infection and of resistance in the host. Unlike most other plant pathogens, M. graminicola has a long latent period during which it evades host defenses. Although this type of stealth pathogenicity occurs commonly in Mycosphaerella and other Dothideomycetes, the largest class of plant-pathogenic fungi, its genetic basis is not known. To address this problem, the genome of M. graminicolawas sequenced completely. The finished genome contains 21 chromosomes, eight of which could be lost with no visible effect on the fungus and thus are dispensable. This eight-chromosome dispensome is dynamic in field and progeny isolates, is different from the core genome in gene and repeat content, and appears to have originated by ancient horizontal transfer from an unknown donor. Synteny plots of the M. graminicola chromosomes versus those of the only other sequenced Dothideomycete, Stagonospora nodorum, revealed conservation of gene content but not order or orientation, suggesting a high rate of intra-chromosomal rearrangement in one or both species. This observed “mesosynteny” is very different from synteny seen between other organisms. A surprising feature of the M. graminicolagenome compared to other sequenced plant pathogens was that it contained very few genes for enzymes that break down plant cell walls, which was more similar to endophytes than to pathogens. The stealth pathogenesis of M. graminicola probably involves degradation of proteins rather than carbohydrates to evade host defenses during the biotrophic stage of infection and may have evolved from endophytic ancestors
Insights into Land Plant Evolution Garnered from the Marchantia polymorpha Genome.
The evolution of land flora transformed the terrestrial environment. Land plants evolved from an ancestral charophycean alga from which they inherited developmental, biochemical, and cell biological attributes. Additional biochemical and physiological adaptations to land, and a life cycle with an alternation between multicellular haploid and diploid generations that facilitated efficient dispersal of desiccation tolerant spores, evolved in the ancestral land plant. We analyzed the genome of the liverwort Marchantia polymorpha, a member of a basal land plant lineage. Relative to charophycean algae, land plant genomes are characterized by genes encoding novel biochemical pathways, new phytohormone signaling pathways (notably auxin), expanded repertoires of signaling pathways, and increased diversity in some transcription factor families. Compared with other sequenced land plants, M. polymorpha exhibits low genetic redundancy in most regulatory pathways, with this portion of its genome resembling that predicted for the ancestral land plant. PAPERCLIP
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