215 research outputs found
Fluctuating ecological networks: a synthesis of maximum entropy approaches for pattern and perturbation detection
Ecological networks such as plant-pollinator systems vary systematically in
space and time. This variability includes fluctuations in global network
properties such as total number and intensity of interactions in the network,
but also in the local properties of individual nodes, such as the number and
intensity of species-level interactions. Fluctuations of local properties can
significantly affect higher-order network features, e.g. robustness and
nestedness. These fluctuations should therefore be controlled for in
applications that rely on null models, including pattern detection,
perturbation experiments and network reconstruction from limited observations.
By contrast, most randomization methods used by ecologists treat node-level
local properties as hard constraints that cannot fluctuate. Here we synthesise
a set of methods based on the statistical mechanics of networks, which we
illustrate with some practical examples. We illustrate how this approach can be
used by experimental ecologists to study the statistical significance of
network patterns and the rewiring of networks under simulated perturbations.
Modelling species heterogeneity, while allowing for local fluctuations around a
theoretically grounded notion of structural equilibrium, will offer a new
generation of models and experiments to understand the assembly and resilience
of ecological networks.Comment: submitte
Fluctuating ecological networks: a synthesis of maximumâentropy approaches for pattern detection and process inference
Ecological networks such as plant-pollinator systems and food webs vary in space and time. This variability includes fluctuations in global properties such as the total number and intensity of interactions in the network but also in the number and intensity of local (i.e. node level) species interactions. Fluctuations of species' properties can significantly affect higher-order network features, for example, robustness and nestedness, and should therefore be taken into account in null models for pattern detection and hypothesis testing. In ecological research, classical null models treat node-level properties as 'hard' constraints that cannot fluctuate. Here, we review and synthesize a set of maximum-entropy methods that allow for fluctuating ('soft') constraints, offering a new addition to the classical toolkit of the ecologist. We illustrate the methods with some practical examples, pointing to currently available open-source computer codes. We clarify how this approach can be used by experimental ecologists to detect non-random patterns with null models that not only rewire, but also redistribute interaction strengths by allowing fluctuations in the enforced constraints. Explicit modelling of interspecific heterogeneity through local (i.e. species level) fluctuations of topological and quantitative constraints offers a statistically robust and expanded (e.g. including weighted links) set of tools to understand the assembly and resilience of ecological networks.Theoretical Physic
Hereditary Angioedema and Psychopathology: Neurobiology, Stress and Attachment Styles
Hereditary Angioedema (HAE) is considered an autosomal dominant disorder, characterized by a quantitativeand/or qualitative deficit of C1 esterase inhibitor. The aim of the study is to establish the relationshipbetween HAE, clinical events, and neurobiological and psychopathologicalparameters, which could influence the phenotype of the disease and thereforeits manifestation in terms of quality, severity and duration of symptoms. Materialsand Methods: observational study, cross-sectional, non-interventional, cohortof 46 patients with diagnosis of hereditary angioedema. ExclusionCriteria: current pharmacological treatment with ACE-inhibitors,glucocorticoids, psychotropic drugs, immunomodulators, anesthetics. A blood sampling was performed to measure cortisol,IL-6, TNF-α and catecholamines, medical examination, psychiatric examination toinvestigate the clinical characteristics of HAE and presence of life events, psychometric evaluation. Any correlation was assessed by Spearman Rho. Results the sample consists of 46 patients, including 22 women (47,8%) e 24 men (52,2%). Averageage of onset of symptoms is equal to 14,61 ± 12,46. High values ??of IL-6 (1,83 ± 3,9) and TNF-α (10,2 ± 27,5) were relatedwith severity of pathology . Conclusions levels of IL-6and TNF-α are in agreement with the increase in the number of attacks of HAE. There is a relationshipbetween increased levels of IL-6 and high scores on Hamilton Depression RatingScale and on Hamilton Anxiety Rating Scale and a higher subjective perceptionof disease severity. The higher was the perceived stress, the greater will bethe subjective perception of disease severity and the presence of pathologicalattachment styles
Application of ozone in fresh-cut iceberg lettuce refrigeration
Recently, technological innovations have been geared to supporting environmental sustainability, also in the fruit and vegetable industry. The application of ozone in the cold storage of fruits and vegetables is a sustainable technology used to improve product quality and its antimicrobial effect, simple use, and characteristic of not leaving any residue, makes this treatment suitable for many applications in this field. The aim of this work was to evaluate the effect of refrigeration at 4°C, associated with ozonization treatment at a concentration of 0.2 ppm on the shelf life of fresh-cut lettuce, compared to a lettuce control stored only at 4°C. Lettuce quality throughout the storage period (7 days) was determined by means of color and microbiological indexes, such as total bacterial count, total coliforms, Escherichia coli, Pseudomonadaceae, yeasts and molds. The lettuce used in the experiment was found to have a low microbiological load. Microbiological results obtained at different storage times have shown that the use of ozone is effective in containing microbial growth during chilling storage of the raw material compared to the refrigerated control. In particular, the positive effects of ozonation were appreciable after the third day of storage. Furthermore, the ozone treatment did not affect the color of the product
Effects of anti-UV film and protective atmosphere on fresh-cut iceberg lettuce preservation
The aim of this research was to study the shelf-life of fresh-cut iceberg lettuce, testing a packaging film manufactured with and without addition of anti-UV compounds, and using two different protective atmospheres (N2/CO2 70/30% and Ar/CO2 80/20%). In order to simulate the most common retail storage conditions, the samples were stored at 6 °C under artificial light by using real supermarket refrigerated exposition stands. The data obtained showed that the use of an anti-UV film always causes a lower quality decay of the product; in any case, the best results were obtained when the anti-UV film was utilized in association with the packaging atmosphere consisting of Ar and CO2 (80/20%) gas mixture
Drought decreases incorporation of recent plant photosynthate into soil food webs regardless of their trophic complexity
Intensive grassland management disrupts below-ground multi-trophic resource transfer in response to drought
Inversion of Tsallis' q-Fourier Transform and the complex-plane generalization
We introduce a complex q-Fourier transform as a generalization of the (real)
one analyzed in [Milan J. Math. {\bf 76} (2008) 307]. By recourse to tempered
ultradistributions we show that this complex plane-generalization overcomes all
troubles that afflict its real counterpart.Comment: 23 pages, no figure
Improvement of patient-reported outcomes in severe allergic asthma by omalizumab treatment : the real life observational PROXIMA study
Background: Data on the prevalence of perennial versus seasonal allergic asthma in Italy are lacking; moreover, there is limited evidence on the effect of omalizumab on patient-reported outcomes in Italian patients with severe allergic asthma. PROXIMA, an observational, multicenter study, was designed to assess the prevalence of perennial versus seasonal allergic asthma (cross-sectional phase) and the effect of omalizumab on improving illness perception, quality of life (QoL) and asthma control of Italian patients with severe allergic asthma (longitudinal phase). Methods: The study included a cross-sectional phase (n = 357) and a longitudinal phase (n = 123): during the longitudinal phase, patients received omalizumab (75-600 mg subcutaneously every month) and were followed-up for 12 months. The primary parameter of cross-sectional phase was prevalence of perennial allergic asthma and that of longitudinal phase was proportion of patients with asthma control (assessed using asthma control questionnaire [ACQ]). Secondary parameters assessed were patients' disease perception, level of asthma control, exacerbation rate during both cross-sectional and longitudinal phases, and patients' compliance to and persistence with omalizumab, and patients' QoL during the longitudinal phase. Results: Most patients (95.8%) had perennial allergies; 81% had polysensitization. Of 99 patients in the per-protocol set, 95 (95.96% [95% CI: 89.98-98.89%]) achieved asthma control (ACQ < 4) at both 6 and 12 months of omalizumab treatment; ACQ score decreased after 6 and 12 months (P < 0.0001). Omalizumab treatment resulted in a significant improvement in QoL and patients' illness perception and 87% decrease in exacerbation rate. The compliance rate with omalizumab was high (73.2%). No new safety signals were identified during treatment. Conclusion: This study demonstrated that in severe allergic asthma, omalizumab improves patient-reported outcomes such as patients' illness perception and QoL, while confirming improvement of asthma control and exacerbation rate reduction in Italian patients
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