Search results for "Co-occurrence"
showing 10 items of 32 documents
Using latent variable models to identify large networks of species‐to‐species associations at different spatial scales
2015
Summary We present a hierarchical latent variable model that partitions variation in species occurrences and co-occurrences simultaneously at multiple spatial scales. We illustrate how the parameterized model can be used to predict the occurrences of a species by using as predictors not only the environmental covariates, but also the occurrences of all other species, at all spatial scales. We leverage recent progress in Bayesian latent variable models to implement a computationally effective algorithm that enables one to consider large communities and extensive sampling schemes. We exemplify the framework with a community of 98 fungal species sampled in c. 22 500 dead wood units in 230 plot…
Anthropogenic threats drive spatio-temporal responses of wildcat on Mt. Etna
2021
Human expansion can cause disturbance and intrusion of invasive species, which are detrimental to small carnivores. We investigated how European wildcats responded to disturbance from mushroom collectors, cattle and feral pigs in Sicily, Italy. We used detections from 76 cameras over 2 surveys (2015–2016 and 2018; camera days = 1985) to run occupancy and co-occurrence models and estimate overlap in activity patterns between species pairs. During 2015–2016, wildcats were detected at the same location with cattle, mushroom hunters and feral pigs at 14.4%, 26.3% and 17.1% of cameras. During 2018, wildcats were detected at the same location with cattle, mushroom hunters and feral pigs at 7.8%, …
Are there so many congeneric species of chironomid larvae in a small stream?
2018
The co-occurrence of larvae of congeneric chironomid species is common in natural stream assemblages, and raises the problem of finding mechanisms to explain the co-existence of species with similar ecological requirements. In this contribution, we explored the co-occurrence of chironomid larvae belonging to congeneric species within four genera of chironomids: Cricotopus, Eukiefferiella, Orthocladius and Rheocricotopus (with 2, 7, 2 and 4 species, respectively) in the headwaters of a small Mediterranean calcareous stream. Due to the intrinsic, natural spatial and temporal variability in these habitats, we studied three different sites at two different seasons within the annual hydrological…
Modulation of Saliva Microbiota through Prebiotic Intervention in HIV-Infected Individuals
2019
Human immunodeficiency virus (HIV) infection is characterized by an early depletion of the mucosal associated T helper (CD4+) cells that impair the host immunity and impact the oral and gut microbiomes. Although, the HIV-associated gut microbiota was studied in depth, few works addressed the dysbiosis of oral microbiota in HIV infection and, to our knowledge, no studies on intervention with prebiotics were performed. We studied the effect of a six-week-long prebiotic administration on the salivary microbiota in HIV patients and healthy subjects. Also, the co-occurrence of saliva microorganisms in the fecal bacteria community was explored. We assessed salivary and feces microbiota compositio…
Fire and phylogenetic structure of soil microbial communities in Mediterranean ecosystems
2017
Tesis llevada a cabo para conseguir el grado de Doctor por la Universidad de Valencia.--2018-02-21.--Sobresaliente Cum laudem
Prevalence and Co-Occurrence of Different Types of Body Dysmorphic Disorder Among Men Having Sex with Men
2020
Body dysmorphic disorder (BDD) is a relatively common psychiatric condition of which the prevalence has not been fully investigated in the non-clinical population, and in particular among men having sex with men (MSM). MSM have proven to be more inclined to develop body dissatisfaction and body image disorders compared to non-MSM. Our study investigates the prevalence of BDD and the prevalence and co-occurrence of muscle dysmorphia (MD) and penile dysmorphic disorder (PDD) in a sample of 261 Italian MSM recruited online. From our data, gathered through self-report measures, the prevalence of BDD, MD, and PDD in our populations was 5.4%, 8.8%, and 4.2%, respectively. Compared to their elders…
Machine learning for rapid mapping of archaeological structures made of dry stones – Example of burial monuments from the Khirgisuur culture, Mongoli…
2020
11 pages; International audience; The present study proposes a workflow to extract from orthomosaics the enormous amount of dry stones used by past societies to construct funeral complexes in the Mongolian steppes. Several different machine learning algorithms for binary pixel classification (i.e. stone vs non-stone) were evaluated. Input features were extracted from high-resolution orthomosaics and digital elevation models (both derived from aerial imaging). Comparative analysis used two colour spaces (RGB and HSV), texture features (contrast, homogeneity and entropy raster maps), and the topographic position index, combined with nine supervised learning algorithms (nearest centroid, naive…
Dissimilarity Application for Medical Imaging Classification
2005
In the traditional way of learning from examples of objects the classifiers are built in a feature space. However, alternative ways can be found by constructing decision rules on dissimilarity (distance) representations. In such a recognition process a new object is described by its distances to (a subset of) die training samples. The use of the dissimilarities is especially of interest when features are difficult to obtain or when they have a little discriminative power. Purpose of this work is the development of an automatic classification system which could be useful for radiologists in the investigation of breast cancer. The software has been designed in the framework of the MAGIC-5 col…
Co-occurrence of discourse markers in English : from juxtaposition to composition
2019
Abstract In this paper, we report on a qualitative analysis of co-occurring discourse markers, that is, sequences of adjacent discourse markers that belong to the same unit but may express different functions. We examine several formal and functional features of these co-occurring strings on the basis of corpus examples extracted from conversational data in English. In particular, we focus on scope, meaning-in-context (or functions), syntactic category and position. Our analysis reveals several degrees of integration: differences in scope allow us to differentiate juxtaposition and combination of markers. In the case of combination, difference in meaning integration allows us to distinguish…
Target Analysis and Retrospective Screening of Multiple Mycotoxins in Pet Food Using UHPLC-Q-Orbitrap HRMS
2019
A comprehensive strategy combining a quantitative method for 28 mycotoxins and a post-target screening for other 245 fungal and bacterial metabolites in dry pet food samples were developed using an acetonitrile-based extraction and an ultrahigh-performance liquid chromatography coupled to high-resolution mass spectrometry (UHPLC-Q-Orbitrap HRMS) method. The proposed method showed satisfactory validation results according to Commission Decision 2002/657/EC. Average recoveries from 72 to 108% were obtained for all studied mycotoxins, and the intra-/inter-day precision were below 9 and 14%, respectively. Results showed mycotoxin contamination in 99% of pet food samples (n = 89) at concentratio…