Search results for "ECOLOGY"

Editorial: From Meristems to Floral Diversity: Developmental Options and Constraints

2021

Probabilistic and preferential sampling approaches offer integrated perspectives of Italian forest diversity

2023

Aim: Assessing the performances of different sampling approaches for documenting community diversity may help to identify optimal sampling efforts and strategies, and to enhance conservation and monitoring planning. Here, we used two data sets based on probabilistic and preferential sampling schemes of Italian forest vegetation to analyze the multifaceted performances of the two approaches across three major forest types at a large scale. Location: Italy. Methods: We pooled 804 probabilistic and 16,259 preferential forest plots as samples of vascular plant diversity across the country. We balanced the two data sets in terms of sizes, plot size, geographical position, and vegetation types. F…

Sex and sexual ornamentation associated with survival of the cyprinid fish, Rutilus rutilus, under disease stress

2013

By conveying information of disease resistance, sexual signals may be used as cues for adaptive mate choice. Here we report observations on survival of laboratory-maintained, wild-collected, sexually mature, ready-to-spawn cyprinid fish, Rutilus rutilus (roach), under accidental epidemic attributed to Flavobacterium psychrophilum, diagnosed using species-specific PCR. The fish were maintained in a single tank. During the 27 days observation period, both the proportion of fish surviving the infection as well as the length-adjusted mean survival time of the fish that died was the highest among the high-ornamented males with large breeding tubercles, intermediary among the low-ornamented males…

La pluralità dello spazio pubblico: una analisi ricognitiva nel centro storico di Palermo

2011

La letteratura inerente allo sviluppo urbano moderno e postmoderno, da Michel Foucault a Henri Lefebvre, ha aperto un dibattito in merito alla concezione classica di apertura/accessibilità dello spazio pubblico, evidenziando aspetti quali la esclusione spaziale, la sorveglianza e il controllo sociale, la questione del “diritto alla città”. Si assiste ad una progressiva riduzione o sostituzione dello spazio pubblico – privatizzato, fortificato, commercializzato – di cui risentono in primis i soggetti più deboli e marginali. Talvolta emergono nuove forme di produzione sociale dello spazio, ad esempio tramite riappropriazione informale di “luoghi di scarto”. Il lavoro di ricerca ha focalizzato…

Growth and Physiological Performance of a Coastal Species Trifolium fragiferum as Affected by a Coexistence with Trifolium repens, NaCl Treatment and…

2021

The aim of the present study was to analyze the growth and physiological performance of two coexisting species, Trifolium fragiferum, and Trifolium repens, under the effect of NaCl and rhizobial symbiosis. Seeds of T. fragiferum and T. repens were collected from populations in the wild, and plants were cultivated in an automated greenhouse, two plants per container. Three basic types of planting were performed: (1) both plants were T. fragiferum (single species), (2) one T. fragiferum and one T. repens (species coexistence), (3) both plants were T. repens (single species). For every basic type, three subtypes were made: (1) non-inoculated, (2) inoculated with rhizobia taken from T. fargifer…

Application of neural networks in diagnostics of chemical compounds based on their infrared spectra

2017

Abstract The paper presents possibilities of using the so-called „finger-print“ identification method and artificial neural network (ANN) for diagnosis of chemical compounds. The construction of a tool specifically developed for this purpose and the ANN, as well as the required conditions for its proper functioning were described. The identification of chemical compounds was tested in two different ways for proving correctness of the assumptions. First of all, initial studies were carried out with the objective to verify the proper functioning of the developed procedure for IR spectrum interpretation. The second research stage was to find out how the properties of artificial neural networks…

First measurements of field metabolic rate in wild juvenile fishes show strong thermal sensitivity but variations between sympatric ecotypes

2021

The relationship between physiology and temperature has a large influence on population-level responses to climate change. In natural settings, direct thermal effects on metabolism may be exaggerated or offset by behavioural responses influencing individual energy balance. Drawing on a newly developed proxy, we provide the first estimates of the thermal performance curve of field metabolism in a wild fish. We investigate the thermal sensitivity of field metabolic rate in two sympatric, genetically distinct ecotypes of Atlantic cod from the Skagerrak coast of southern Norway. The combined ecotype median of field metabolic rate increased with increasing temperature until around 16°C, coincide…

Acaricidal Activity of Bufadienolides Isolated from Drimia pancration against Tetranychus urticae, and Structural Elucidation of Arenobufagin-3-O-α-L…

2022

Chemical characterization of the bulbs of Drimia pancration was conducted to isolate four steroidal saponins (1–4). Earlier, we focused on the structural elucidation of compounds 1–3. Herein, by means of 1H-NMR, 13C-NMR, Nuclear Overhauser Effects (NOE), and 2D-NMR spectra, the full stereochemical structure of 4 is reported, and all the 1H and 13C signals are assigned. Compounds 1–4 were tested for their acaricidal properties against the two-spotted spider mite Tetranychus urticae. Our results showed excellent activity of compound 1, with an LD50 (µg/cm2) of 0.29 and a LD90 (µg/cm2) of 0.96, whereas compounds 2, 3, and 4 showed moderate activity. Furthermore, t…

Understanding the microbial biogeography of ancient human dentitions to guide study design and interpretation

2021

AbstractThe oral cavity is a heterogeneous environment, varying in factors such as pH, oxygen levels, and salivary flow. These factors affect the microbial community composition and distribution of species in dental plaque, but it is not known how well these patterns are reflected in archaeological dental calculus. In most archaeological studies, a single sample of dental calculus is studied per individual and is assumed to represent the entire oral cavity. However, it is not known if this sampling strategy introduces biases into studies of the ancient oral microbiome. Here, we present the results of a shotgun metagenomic study of a dense sampling of dental calculus from four Chalcolithic i…

Tooth replacement rates in early chondrichthyans: a qualitative approach

2009

The continuous replacement of teeth throughout their lifetime is a common characteristic of most chondrichthyans. This process was already present in the earliest representatives of the group. It has been well established that different species of extant sharks show rapid tooth replacement rates; however, some authors have suggested that in early chondrichthyans this rate might have been much slower. Here we present a qualitative approach to analyse tooth replacement rates in the Early Devonian shark Leonodus carlsi, the earliest tooth-bearing shark known to date. For this, we have examined 1,103 isolated teeth from Celtiberia, Spain. Our study provides strong evidences of an extremely slow…