http://hdl.handle.net/20.500.11960/2349 Sat, 29 Aug 2026 16:39:57 GMT 2026-08-29T16:39:57Z http://hdl.handle.net/20.500.11960/4903 Title: UAV RGB and Multispectral Data for Grapevine Viral Disease Symptoms Classification Authors: Portela, Fernando; Sousa, Joaquim J.; Paredes, Claudio A.; Pádua, Luis; Morais, Raul Abstract: Grapevine viral diseases impact vineyard productivity, requiring fast and reliable detection. This study evaluates RGB, and multispectral data acquired from unmanned aerial vehicles (UAVs) combined with object-based image analysis (OBIA) and machine learning for the detection of viral disease symptoms in vineyards. Different datasets were created for training and validating random forest classifiers using vegetation indices computed from RGB or multispectral data to classify between viral symptoms, no visible symptoms, and symptoms of nutritional deficiencies. The model trained with the RGB dataset obtained an accuracy of 80%. In contrast, when using the multispectral dataset, an accuracy of 95% was reached. Vegetation indices such as normalized difference vegetation index (NDVI), green normalized difference vegetation index (GNDVI), red edge green index (REGI), and green-red vegetation index (GRVI) were among the ones with the higher contribution in distinguishing between healthy, virus infected, and nutrient-deficient leaves. The integration of these technologies provides an approach for efficient and sustainable vineyard monitoring, with potential for future optimization through multi-temporal data analysis. Wed, 01 Jan 2025 00:00:00 GMT http://hdl.handle.net/20.500.11960/4903 2025-01-01T00:00:00Z http://hdl.handle.net/20.500.11960/4897 Title: Mapping of the invasive species Hakea sericea using Unmanned Aerial Vehicle (UAV) and worldview-2 imagery and an object-oriented approach Authors: Alvarez-Taboada, Flor; Paredes, Claudio; Julián-Pelaz, Julia Abstract: Invasive plants are non-native species that establish and spread in their new location, generating a negative impact on the local ecosystem and representing one of the most important causes of the extinction of local species. The first step for the control of invasion should be directed at understanding and quantification of their location, extent and evolution, namely the monitoring of the phenomenon. In this sense, the techniques and methods of remote sensing can be very useful. The aim of this paper was to identify and quantify the areas covered by the invasive plant Hakea sericea using high spatial resolution images obtained from aerial platforms (Unmanned Aerial Vehicle: UAV/drone) and orbital platforms (WorldView-2: WV2), following an object-oriented image analysis approach. The results showed that both data were suitable. WV2reached user and producer accuracies greater than 93% (Estimate of Kappa (KHAT): 0.95), while the classifications with the UAVorthophotographs obtained accuracies higher than 75% (KHAT: 0.51). The most suitable data to use as input consisted of using all of the multispectral bands that were available for each image. The addition of textural features did not increase the accuracies for the Hakea sericea class, but it did for the general classification using WV2. Fri, 01 Sep 2017 00:00:00 GMT http://hdl.handle.net/20.500.11960/4897 2017-09-01T00:00:00Z http://hdl.handle.net/20.500.11960/4895 Title: Occurrence and Characterization of Antimicrobial-Resistant and Virulent Enterococcus spp. in Dog Feces from Urban Green Spaces in Porto (Portugal) Authors: Ribeiro, Jessica; Lameiras, Rui; Silva, Vanessa; Igrejas, Gilberto; Cortez Nunes, Francisco; Ribeiro, Ana Isabel; Mateus, Teresa Letra; Poeta, Patrícia Abstract: Background/Objectives: Enterococcus spp. are important indicators of AMR and potential opportunistic pathogens. Urban green spaces, frequented by dogs and humans, may serve as reservoirs for resistant bacteria. This study assessed the occurrence, AMR profiles, and virulence traits of Enterococcus spp. in dog feces from urban green spaces in Porto (Portugal). Methods: In December 2023 and May 2024, 240 dog fecal samples were collected from 12 urban green spaces across Porto. Enterococcus spp. were isolated using selective culture, identified to species level, and tested for antimicrobial susceptibility following CLSI guidelines. PCR screening was performed for resistance genes (vanA, vanB, erm(A/B/C), vatD/E, tet(M/O/L/K)) and virulence genes (gelE, ace). Environmental and AcademicEditor: JuheeAhn Received: 16February2026 Revised: 23March2026 Accepted: 2April2026 Published: 8 April2026 Copyright: ©2026bytheauthors. Licensee MDPI,Basel,Switzerland. This article is an open access article distributed under the termsand conditions of the Creative Commons Attribution (CC BY)license. socioeconomic features, including vegetation density (NDVI), presence of water features, and neighborhood deprivation (EDI), were recorded to explore associations with bacterial occurrence and traits. Results: Thirty-two isolates were recovered, mainly E. faecium (n = 9) and E. faecalis (n = 7). High resistance rates were observed to tetracycline (56.3%) and quinupristin/dalfopristin (37.5%), with lower rates for vancomycin, teicoplanin, and ciprofloxacin (3.1%), and imipenem (6.3%). Tet(M) was the most prevalent resistance gene (40.6%), and gelE and ace were frequently detected, often co-occurring with resistance determinants. Distribution of resistance and virulence genes varied across green spaces, with widely used parks showing more isolates. Vegetation density and water features were not directly associated with bacterial recovery. Conclusions: Dog feces in urban green spaces contribute to localized AMR hotspots, acting as potential reservoirs of resistant and potentially pathogenic Enterococcus spp. These findings highlight the importance of One Health strategies for urban sanitation and AMR surveillance. Wed, 08 Apr 2026 00:00:00 GMT http://hdl.handle.net/20.500.11960/4895 2026-04-08T00:00:00Z http://hdl.handle.net/20.500.11960/4748 Title: Helicobacter pylori and Non-Helicobacter pylori Helicobacter (NHPH) Zoonotic Infections: A Survey Among Greek Veterinarians Aiming to Enhance Communication Authors: Fragkiadaki, Eirini; Nunes, Francisco Cortez; Linou, Maria; Martinez-Gonzalez, Beatriz; Sgouras, Dionyssios N.; Mateus, Teresa Letra Abstract: Helicobacter species affect humans and animals, mainly causing gastrointestinal but also extra-gastrointestinal pathologies. Besides Helicobacter pylori, which is the main human pathogen, Non-Helicobacter pylori Helicobacters (NHPH) are also associated with human diseases, thus raising concern about their zoonotic potential. Veterinarians are considered a risk group for NHPH infections and act as first-line communicators to animal owners about their prophylaxis. Therefore, we aimed to assess the knowledge and perception of veterinarians working in Greece about Helicobacter pylori and NHPH by asking them to participate anonymously in an online 34-question survey. The questionnaire consisted of three sections regarding environmental exposure to Helicobacter spp.; know-how about clinical signs in various species, including personal human experience; and willingness to get updated information about NHPH. Of the 111 respondents, 41.4% had not heard of H. suis (NHPH), and 35.0% were unawareof the species that could be affected. Almost 60.0% of companion animal veterinarians rarely suspect and 20.0% never suspect Helicobacter spp. infections in the case of gastritis. Nevertheless, 41.0% of respondents considered Helicobacter as zoonotic, and 87.0% wanted to receive information via professional channels and brochures. Despite the limited number of respondents and the exploratory nature of our study, as with similar data from Portugal, we emphasize the need to train veterinarians to have a more targeted focus on the zoonotic potential of Helicobacter within a One Health approach. Wed, 18 Feb 2026 00:00:00 GMT http://hdl.handle.net/20.500.11960/4748 2026-02-18T00:00:00Z