45 research outputs found
Use of very high-resolution airborne images to analyse 3d canopy architecture of a vineyard
Differencing between green cover and grape canopy is a challenge for vigour status evaluation in viticulture. This paper presents the acquisition methodology of very high-resolution images (4 cm), using a Sensefly Swinglet CAM unmanned aerial vehicle (UAV) and their processing to construct a 3D digital surface model (DSM) for the creation of precise digital terrain models (DTM). The DTM was obtained using python processing libraries. The DTM was then subtracted to the DSM in order to obtain a differential digital model (DDM) of a vineyard. In the DDM, the vine pixels were then obtained by selecting all pixels with an elevation higher than 50 [cm] above the ground level. The results show that it was possible to separate pixels from the green cover and the vine rows. The DDM showed values between â0.1 and + 1.5 [m]. A manually delineation of polygons based on the RGB image belonging to the green cover and to the vine rows gave a highly significant differences with an average value of 1.23 [m] and 0.08 [m] for the vine and the ground respectively. The vine rows elevation is in good accordance with the topping height of the vines 1.35 [m] measured on the field. This mask could be used to analyse images of the same plot taken at different times. The extraction of only vine pixels will facilitate subsequent analyses, for example, a supervised classification of these pixels
Calystegine degradation capacities of microbial rhizosphere communities of Zea mays (calystegine-negative) and Calystegia sepium (calystegine-positive)
Calystegines are tropane alkaloids produced by the roots of a few plant species. A bioassay was developed to identify roots with a microbial rhizosphere community capable of calystegine degradation (i.e. MCD roots). In a field survey, the proportion of MCD roots of Zea mays (calystegine-negative) varied from 20 to 80%. In field experiments, the proportions of MCD roots of Z. mays and Calystegia sepium (calystegine-positive) grown in a particular plot were similar to each other but varied with time and, overall, were higher than those of Z. mays roots from adjacent plots free of C. sepium. In autoclaved soil, no root of C. sepium or Z. mays plants propagated as seeds was MCD, indicating that calystegine-degrading microorganisms were not seed-borne. However, MCD roots were found as early as 1 day after planting of rhizomes of C. sepium in autoclaved soil or planting of axenic seedlings of either plant in natural soil microcosms. In total, microorganisms capable of degrading calystegines were harboured not only in the rhizosphere of the calystegine-producing plant but also in that of the calystegine-negative plant and probably in bulk soi
Large temporal variations of functional properties of outdoor equestrian arena surfaces and a new concept of evaluating reactivity with light weight deflectometer settlement curves
Sports physiological properties of ten sand or sand-mineral outdoor arenas, five with vertical drainage systems and five with an ebb and flow like system were assessed over a period of eight weeks. For each arena, the riding zone was spatially delineated, nine locations at medium to intensely used zones were selected by simple random sampling and used along the whole measurement period. A total of 72 values for the dynamic deflection modulus (Evd), attenuation (s/v), settlement (s) and moisture content (Vol %) were analyzed for each arena. A novel technique to analyze the settlement curves of the light weight deflectometer (LWD) to describe reactivity of the footing surface was introduced. Statistical testing was done by linear mixed models. Three of the five arenas with a vertical watering system were judged to be hard (Evd > 20 MN/m2), whereas all five arenas with an ebb and flow like watering systems were medium hard (EvdâŻ=âŻ10-20 MN/m2) over the entire eight weeks. Significant (p<0.01) temporal differences in Evd, s/v and moisture were demonstrated for both watering systems; however, the spatial and temporal variations were much lower with the ebb-flow system. Temporal consistency in the parameters over the test weeks appeared to be a criterion for stability of the arena surface. The analysis of the settlement curves of the LWD showed that the slope symmetry has a large potential to describe the restoration of the energy of an equestrian surface than only the settlement, which requires further validation
Augmenting a convolutional neural network with local histograms ::a case study in crop classification from high-resolution UAV imagery
The advent of affordable drones capable of taking high resolution images of agricultural fields creates new challenges and opportunities in aerial scene understanding. This paper tackles the problem of recognizing crop types from aerial imagery and proposes a new hybrid neural network architecture which combines histograms and convolutional units. We evaluate the performance of the proposed model on a 23-class classification task and compare it to other models. The result is an improvement of the classification performance
Fourier Disentangled Multimodal Prior Knowledge Fusion for Red Nucleus Segmentation in Brain MRI
Early and accurate diagnosis of parkinsonian syndromes is critical to provide
appropriate care to patients and for inclusion in therapeutic trials. The red
nucleus is a structure of the midbrain that plays an important role in these
disorders. It can be visualized using iron-sensitive magnetic resonance imaging
(MRI) sequences. Different iron-sensitive contrasts can be produced with MRI.
Combining such multimodal data has the potential to improve segmentation of the
red nucleus. Current multimodal segmentation algorithms are computationally
consuming, cannot deal with missing modalities and need annotations for all
modalities. In this paper, we propose a new model that integrates prior
knowledge from different contrasts for red nucleus segmentation. The method
consists of three main stages. First, it disentangles the image into high-level
information representing the brain structure, and low-frequency information
representing the contrast. The high-frequency information is then fed into a
network to learn anatomical features, while the list of multimodal
low-frequency information is processed by another module. Finally, feature
fusion is performed to complete the segmentation task. The proposed method was
used with several iron-sensitive contrasts (iMag, QSM, R2*, SWI). Experiments
demonstrate that our proposed model substantially outperforms a baseline UNet
model when the training set size is very small
Erhöhte HumusvorrÀte in einem siebenjÀhrigen Agroforstsystem in der Zentralschweiz
Moderne Agroforstsysteme haben das Potenzial, eine produktive Landwirtschaft mit verbesserter Erreichung der «Umweltziele Landwirtschaft» zu verbinden. Diese Systeme werden in der Schweiz allerdings erst seit kurzem von wenigen Landwirten getestet, daher liegen bisher kaum Daten zu den Umweltwirkungen von modernen Agroforstsystemen vor. In dieser Studie untersuchten wir, wie sich die HumusvorrĂ€te in einem siebenjĂ€hrigen Agroforstsystem in der Zentralschweiz verĂ€ndert haben. Unsere Resultate zeigen, dass bereits nach sieben Jahre eine substanzielle Humusanreicherung (+18 %) in der Baumreihe verglichen mit der kultivierten FlĂ€che zu beobachten ist. Erstaunlicherweise beschrĂ€nkte sich die Humusanreicherung nicht nur auf den Oberboden, sondern konnte auch bis in eine Tiefe von 60 cm nachgewiesen werden. Eine erste SchĂ€tzung der jĂ€hrlichen Humusanreicherung in der untersuchten Agroforstparzelle betrĂ€gt 0,86 t Kohlenstoff pro Hektare und Jahr beziehungsweise 91 kg Stickstoff pro Hektare und Jahr fĂŒr die Bodentiefe 0â60 cm. Die Magnitude dieser ersten SchĂ€tzung zeigt, dass die weitere Erforschung der Humusdynamik in Agroforstsystemen aus Sicht des Boden-, Klima- und GewĂ€sserschutzes von grosser Bedeutung ist
ESPEN Guideline: clinical nutrition in inflammatory bowel disease
Crohnâs disease; Ulcerative colitis; Nutritional therapyMalaltia de Crohn; Colitis ulcerosa; TerĂ pia nutricionalEnfermedad de Crohn; Colitis ulcerosa; Terapia nutricionalIntroduction: the ESPEN Guideline offers a multidisciplinary focus on clinical nutrition in inflammatory bowel disease (IBD).
Methodology: the guideline is based on a extensive systematic review of the literature, but relies on expert opinion when objective data are
lacking or inconclusive. The conclusions and 64 recommendations have been subject to full peer review and a Delphi process, in which uniformly
positive responses (agree or strongly agree) were required.
Results: IBD is increasingly common and potential dietary factors in its etiology are briefly reviewed. Malnutrition is highly prevalent in IBD â
especially in Crohnâs disease. Increased energy and protein requirements are observed in some patients. The management of malnutrition in IBD
is considered within the general context of support for malnourished patients. Treatment of iron deficiency (parenterally, if necessary) is strongly
recommended. Routine provision of a special diet in IBD is not, however, supported. Parenteral nutrition is indicated only when enteral nutrition
has failed or is impossible. The recommended perioperative management of patients with IBD undergoing surgery accords with general ESPEN
guidance for patients having abdominal surgery. Probiotics may be helpful in UC but not in Crohnâs disease. Primary therapy using nutrition to
treat IBD is not supported in ulcerative colitis but is moderately well supported in Crohnâs disease, especially in children, where the adverse
consequences of steroid therapy are proportionally greater. However, exclusion diets are generally not recommended and there is little evidence
to support any particular formula feed when nutritional regimens are constructed.
Conclusions: available objective data to guide nutritional support and primary nutritional therapy in IBD are presented as 64 recommendations,
of which 9 are very strong recommendations (grade A), 22 are strong recommendations (grade B), and 12 are based only on sparse evidence
(grade 0); 21 recommendations are good practice points (GPP).IntroducciĂłn: la guĂa ESPEN ofrece un enfoque multidisciplinar de la nutriciĂłn clĂnica en la enfermedad inflamatoria intestinal (EII). MetodologĂa: la guĂa se basa en una extensa revisiĂłn sistemĂĄtica de la literatura y en la opiniĂłn de expertos cuando faltan datos objetivos o estos no son concluyentes. Las conclusiones y las 64 recomendaciones han sido objeto de una revisiĂłn completa por pares y de un proceso Delphi en el que se requerĂan respuestas fuertemente positivas (de acuerdo o totalmente de acuerdo). Resultados: la EII es cada vez mĂĄs comĂșn y se revisan brevemente los posibles factores dietĂ©ticos en su etiologĂa. La desnutriciĂłn es muy prevalente en la EII, especialmente en la enfermedad de Crohn. En algunos pacientes se observan mayores requerimientos de energĂa y proteĂnas. El manejo de la desnutriciĂłn en la EII se considera dentro del contexto general de apoyo a los pacientes desnutridos. Se recomienda fuertemente el tratamiento de la deficiencia de hierro (por vĂa parenteral, si es necesario). Sin embargo, no se aconseja la prescripciĂłn de rutina de una dieta especial en la EII. La nutriciĂłn parenteral estĂĄ indicada solo cuando la nutriciĂłn enteral ha fallado o es imposible. El manejo perioperatorio recomendado de los pacientes con EII sometidos a cirugĂa se hace de acuerdo con la guĂa general de la ESPEN para pacientes sometidos a cirugĂa abdominal. Los probiĂłticos pueden ser Ăștiles en la CU pero no en la enfermedad de Crohn. El tratamiento primario con nutriciĂłn para tratar la EII no estĂĄ respaldado en la colitis ulcerosa, aunque estĂĄ moderadamente bien soportado en la enfermedad de Crohn, especialmente en los niños, donde las consecuencias adversas de la terapia con esteroides son proporcionalmente mayores. Sin embargo, las dietas de exclusiĂłn generalmente no se recomiendan y hay poca evidencia que respalde cualquier fĂłrmula de nutriciĂłn en particular cuando se realizan regĂmenes nutricionales. Conclusiones: los datos objetivos disponibles para guiar el apoyo nutricional y la terapia nutricional primaria en la EII se presentan como 64 recomendaciones, de las cuales 9 son recomendaciones muy fuertes (grado A), 22 son recomendaciones fuertes (grado B) y 12 se basan solo en evidencia escasa (grado 0); 21 recomendaciones son recomendaciones de buenas prĂĄcticas (GPP).El proceso de la guĂa ha sido financiado exclusivamente por la ESPEN
Predicting the Progression of Mild Cognitive Impairment Using Machine Learning: A Systematic and Quantitative Review
Context. Automatically predicting if a subject with Mild Cognitive Impairment (MCI) is going to progress to Alzheimer's disease (AD) dementia in the coming years is a relevant question regarding clinical practice and trial inclusion alike. A large number of articles have been published, with a wide range of algorithms, input variables, data sets and experimental designs. It is unclear which of these factors are determinant for the prediction, and affect the predictive performance that can be expected in clinical practice. We performed a systematic review of studies focusing on the automatic prediction of the progression of MCI to AD dementia. We systematically and statistically studied the influence of different factors on predictive performance. Method. The review included 172 articles, 93 of which were published after 2014. 234 experiments were extracted from these articles. For each of them, we reported the used data set, the feature types (defining 10 categories), the algorithm type (defining 12 categories), performance and potential methodological issues. The impact of the features and algorithm on the performance was evaluated using t-tests on the coefficients of mixed effect linear regressions. Results. We found that using cognitive, fluorodeoxyglucose-positron emission tomog-raphy or potentially electroencephalography and magnetoencephalography variables significantly improves predictive performance compared to not including them (p=0.046, 0.009 and 0.003 respectively), whereas including T1 magnetic resonance imaging, amyloid positron emission tomography or cerebrospinal fluid AD biomarkers does not show a significant effect. On the other hand, the algorithm used in the method does not have a significant impact on performance. We identified several methodological issues. Major issues, found in 23.5% of studies, include the absence of a test set, or its use for feature selection or parameter tuning. Other issues, found in 15.0% of studies, pertain to the usability of the method in clinical practice. We also highlight that short-term predictions are likely not to be better than predicting that subjects stay stable over time. Finally, we highlight possible biases in publications that tend not to publish methods with poor performance on large data sets, which may be censored as negative results. Conclusion. Using machine learning to predict MCI to AD dementia progression is a promising and dynamic field. Among the most predictive modalities, cognitive scores are the cheapest and less invasive, as compared to imaging. The good performance they offer question the wide use of imaging for predicting diagnosis evolution, and call for further exploring fine cognitive assessments. Issues identified in the studies highlight the importance of establishing good practices and guidelines for the use of machine learning as a decision support system in clinical practice
Utilisation d'images à trÚs haute résolution pour quantifier l'érosion et proposer des mesures préventives ciblées
LâĂ©rosion hydrique est, avec le tassement et la pollution au cuivre, lâune des causes majeures de dĂ©gradation des sols viticoles en Suisse. Il est maintenant bien connu que lâĂ©rosion diminue Ă long terme leur fertilitĂ© (Vanwalleghema et al., 2017), quâelle contribue Ă la charge des eaux de surface en sĂ©diments et en intrants tels que pesticides et Cu (Fulda et al., 2015). Bien quâen Suisse, lâinterrang des vignes soit souvent enherbĂ©, lâĂ©rosion reste un problĂšme 1) au niveau du cavaillon, gĂ©nĂ©ralement travaillĂ© ou dĂ©sherbĂ©, 2) lors de replantations et 3) sur les sols sensibles (peu profonds) entiĂšrement dĂ©sherbĂ©s. Les phĂ©nomĂšnes Ă©rosifs sont accentuĂ©s par les sols en pentes ainsi quâune texture souvent limoneuse, peu cohĂ©sive (Zufferey et Murisier, 2004).
La quantification du volume de terre Ă©rodĂ©e permet de dĂ©terminer la dĂ©gradation spĂ©cifique liĂ©e Ă lâĂ©rosion qui est la quantitĂ© de terre perdue. Les mĂ©thodes utilisĂ©es jusquâĂ prĂ©sent pour estimer le volume de terre Ă©rodĂ©e sont par exemple, selon Prasuhn et Fischler (2007), la mesure sur la longueur de la rigole, de sections transversales Ă intervalles rĂ©guliers (de 1 Ă 4 m), oĂč est mesurĂ©e la largeur au point dâinflexion et au fond et la profondeur en trois points. Une autre mĂ©thode est celle de Brenot et al. (2008) qui consiste Ă mesurer la distance entre le sol et le greffon. Ainsi, il est possible dâestimer la quantitĂ© de terre Ă©rodĂ©e depuis lâannĂ©e de plantation. Ces deux mĂ©thodes ont cependant le dĂ©savantage dâĂȘtre gĂ©nĂ©ralement gourmandes en temps (Nachtergaele et Poesen, 1999). LâaccĂšs aux drones Ă des prix relativement bas et lâobtention dâimages ainsi que de modĂšles numĂ©riques de surface (MNS) Ă trĂšs haute rĂ©solution permettent dorĂ©navant de suivre les phĂ©nomĂšnes dâĂ©rosion hydrique (Klaus et al., 2014â; dâOleire-Oltmanns et al., 2012â; Pineux et al., 2017). La mĂ©thode prĂ©sentĂ©e ici combine ces nouveaux outils
Calystegine degradation capacities of microbial rhizosphere communities of Zea mays (calystegine-negative) and Calystegia sepium (calystegine-positive)
ISSN:0168-6496ISSN:1574-694