2,761 research outputs found

    Feature Learning for Multispectral Satellite Imagery Classification Using Neural Architecture Search

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    Automated classification of remote sensing data is an integral tool for earth scientists, and deep learning has proven very successful at solving such problems. However, building deep learning models to process the data requires expert knowledge of machine learning. We introduce DELTA, a software toolkit to bridge this technical gap and make deep learning easily accessible to earth scientists. Visual feature engineering is a critical part of the machine learning lifecycle, and hence is a key area that will be automated by DELTA. Hand-engineered features can perform well, but require a cross functional team with expertise in both machine learning and the specific problem domain, which is costly in both researcher time and labor. The problem is more acute with multispectral satellite imagery, which requires considerable computational resources to process. In order to automate the feature learning process, a neural architecture search samples the space of asymmetric and symmetric autoencoders using evolutionary algorithms. Since denoising autoencoders have been shown to perform well for feature learning, the autoencoders are trained on various levels of noise and the features generated by the best performing autoencoders evaluated according to their performance on image classification tasks. The resulting features are demonstrated to be effective for Landsat-8 flood mapping, as well as benchmark datasets CIFAR10 and SVHN

    Tautomeric Equilibria Studies by Mass Spectrometry

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    Tautomerism in organic chemistry has been extensively studied in condensed phase by spectrometric methods, mainly by IR and NMR techniques. Mass spectrometry studies start 40 years ago but just recently it has been recognized the importance of the mass spectral data for the study of tautomerism in the gas phase.
Mass spectrometry can provide valuable information in regard to tautomeric equilibria when studying mass spectra among the members of different families of organic compounds.
The relevance of the mass spectral data resides on several facts but there are two that are of key importance:
1-	Mass spectral fragmentation assignments should be tautomer specific since the corresponding abundances ratios are supposed to be correlated to the keto/enol contents.
2-	Ionization in the ion source is supposed to have no effect on the position of the equilibrium so that the results reflect the tautomers content in the gas phase previous to ionization.
Some of the carbonylic compounds do not exhibit noticeable tautomerism so the fragment abundances assigned to the enol form is very low or not measurable. Since enolization is more noticeable in the case of thio-derivatives (which correlates adequately with the oxygenated analogues), the study of their mass spectra is an interesting choice to reach some degree of generalization. 
In addition, experimental findings are supported by semiempirical theoretical calculations, which probed to be adequate not only for supporting tendency correlations among the members of a compound family but also to calculate heats of tautomerization in gas phase.
Reports using mass spectrometry for tautomerism are becoming less common. One of the reasons is that now it would appear that the interpretation of MS results is not as straightforward as it was once believed, even though in a recent review it was written that: “Mass spectrometry is the most informative and practical method for studying and identifying tautomers in the gas phase” [1]. 
In fact, mass spectrometry seems to be very informative for studying and identifying tautomers, because in this case external factors like solvents, intermolecular interactions, etc., can be excluded by transferring the tautomeric system into gas phase, where the process becomes truly unimolecular [1].
This review covers the study of Tautomerism by Mass Spectrometry in the last four decades. 
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    Becoming a teacher: conceptual and practice development in the learning and skills sector

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    Drawing on a mixed-methods study of in-service learning and skills sector (LSS) trainees, comprising beginning- and end-of-year surveys and six longitudinal case studies together with literature on trainees’ development in the LSS, schools and higher education sectors, conceptual and practice development continua are proposed. Conceptions become more multi-dimensional and increasingly link teaching and learning whilst initial concern with the practicalities of teaching is followed by recognition of learners’ needs. Next, greater emphasis is placed on learner autonomy and catering for individuals’ needs and finally assessment and evaluation is used systematically to shape practice. The continua offer an understanding of the subtleties and complexities of trainee development allowing for different starting and end points and accommodating varied work contexts. I argue that this provides a more adequate basis for the development of initial teacher education (ITE) than the prescriptive approach embedded within recent LSS ITE policy reforms

    PRELIMINARY ANALYSIS OF SLEDGE REACTION FORCES DURING CYCLICAL LOADING OF THE TRICEPS SURAE

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    To date, no methodology exists that can measure Achilles tendon stiffness in a controlled dynamic situation while simultaneously investigating tendon and joint stiffness interactions. Stiffness refers to the ratio between force and elongation, and the aim of this preliminary study was to establish an analysis protocol for sledge reaction forces during cyclical loading of the triceps surae. Results indicated the magnitude of forces was just under 50% of body weight, which was expected. Removal of the first two trials from analysis reduced standard deviation and 95% confidence interval of plantarflexor force, contact time and contact time-flight time ratio, suggesting this protocol is suitable to ensure data gathered is repeatable and consistent. Future work using inverse dynamics and ultrasound shall provide information on Achilles tendon loading and stiffness

    THE EFFECT OF INCREASED LOADING ON PLANTARFLEXOR FUNCTION DURING A STRETCH-SHORTENING CYCLE TASK

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    Increasing loading is one of the most common methods used to increase exercise intensity but it is important to consider the influence of the increase on subsequent force output, rate of force development and, in the case of plyometric exercise, contact time. The aim of this study was to investigate the effect of altering loading on plantarflexor force and force production during a fast stretch-shortening cycle task. Results showed load increased force production and contact time and decreased flight time and reactive strength index. These results have important implications for practitioners in determining the optimal method of increasing training intensity in order to avoid negative training effects

    PLANTARFLEXOR FORCE PRODUCTION IN ISOMETRIC AND STRETCH-SHORTENING CYCLE TASKS

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    The ankle joint and its surrounding musculature are vital in sprinting, and recent work has developed a method to isolate the plantarflexor muscle group for analysis of its force-producing capabilities. The aim of this study was to compare values for plantarflexor force obtained using isometric dynamometry and an adapted force sledge in twenty healthy subjects. Results showed low relationships between isometric and dynamic strength measures, probably because the dynamic test utilises a stretch-shortening cycle. No relationship was observed between isometric strength and the sledge foot plate height during the task with a moderate relationship observed between dynamic strength and plate height. This highlights the important role the Achilles tendon plays in dynamic tasks

    DO FLEXIBILITY SCREENING TESTS REFLECT JOINT RANGE OF MOTION DURING DYNAMIC TASKS?

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    The aim of this study was to investigate if ankle joint range of motion (ROM) during a functional screen test was related to ankle ROM and plantarflexor reactive strength index (RSI) during a dynamic task. The three measures were correlated for the dominant and non-dominant legs to identify what relationship, if any, existed between the three measures. Results showed that there was no relationship between the two measures of ROM, and ROM during the sledge task was positively related to plantarflexor RSI. This is in contrast to other work, possibly due to the isolation of the plantarflexor muscles in the sledge task. Interestingly, between-leg relationships were lower in the dynamic task, suggesting increased variability in the movement strategies used or underlying training differences

    Carrapato e vermes: inimigos do gado e do produtor.

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    Helicoverpa armigera preference and performance on three cultivars of short-duration pigeonpea (Cajanus cajan): the importance of whole plant assays

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    BACKGROUND Helicoverpa armigera is a major pest of pigeonpea (Cajanus cajan). Efforts to develop pigeonpea varieties resistant to H. armigera attack have been met with limited success, despite reports of high levels of resistance to H. armigera in wild relatives of pigeonpea and reports of low to moderate levels of resistance in cultivated varieties. Here we examined H. armigera oviposition preference and larval performance on whole plants of three cultivars of short-duration pigeonpea: a susceptible control (ICPL 87) and two cultivars with purported host–plant resistance (ICPL 86012 and ICPL 88039). RESULTS In our no-choice oviposition experiment, H. armigera laid similar numbers of eggs on all three cultivars tested, but under choice conditions moths laid slightly more eggs on ICPL 88039. Larval growth and development were affected by cultivar, and larvae grew to the largest size (weight) and developed fastest on ICPL 86012. Moths laid most of their eggs on floral structures, sites where subsequent early instar larvae overwhelmingly fed. Experimentally placing neonate larvae at different locations on plants demonstrated that larvae placed on flowers experienced greater survival, faster development, and greater weight gain than those placed on leaves. The type and density of trichomes (a potential resistance trait) differed among cultivars and plant structures, but larvae selected to feed at sites where trichomes were absent. CONCLUSION Future work examining host–plant resistance against H. armigera should incorporate the behavioural preference of moths and larvae in experiments using whole plants as opposed to bioassays of excised plant parts in Petri dishes. © 2022 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry
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