509 research outputs found
Un estudio sobre la paloma doméstica Columba livia var. en la ciudad de Jena, Alemania
Se estudió una población de palomas domésticas, Columba livia var. en la ciudad de Jena, Alemania, entre julio y diciembre de 2007, mediante censos diarios en diez transectos de un sector de la ciudad, cinco en áreas urbanas y cinco en áreas suburbanas. La densidad poblacional de palomas en las zonas urbanas resultó mayor que en las zonas suburbanas, aunque no se encontraron diferencias significativas entre ambas áreas. Las actividades de comportamiento registradas por las palomas fueron de descanso, de mantenimiento del plumaje, de vuelo, alimentación, baños de sol y elección de lugares donde posarse. Las actividades se producen en lugares como tejados altos y aleros de edificios en zonas urbanas y tejados y aleros de balcones en zonas suburbanas. El fenotipo de plumaje más abundante para ambas áreas durante el periodo del censo fue Blue bar.
Palabras clave: Columba livia var., paloma doméstica, aves urbanas, Jena, Alemania.A population of feral pigeons, Columba livia var. was conducted in the city of Jena, Germany, from July to December 2007. Daily censuses were conducted by walking ten transects in a selected area of the city, five transects in built up areas and five in the suburbs. Pigeon population density was higher in urban areas than in suburbs but differences were not significant. Main behavioural activities recorded were resting, preening, flying, eating, sunning and roosting. Regular locations of activities were rooftops and roof edges in urban areas, and rooftops, eaves on balconies in suburban areas. The plumage phenotype most frequently recorded in both areas was Blue bar.
Key words: Columba livia var., Feral pigeons, Urban birds, Jena city, Germany.Se estudió una población de palomas domésticas, Columba livia var. en la ciudad de Jena, Alemania, entre julio y diciembre de 2007, mediante censos diarios en diez transectos de un sector de la ciudad, cinco en áreas urbanas y cinco en áreas suburbanas. La densidad poblacional de palomas en las zonas urbanas resultó mayor que en las zonas suburbanas, aunque no se encontraron diferencias significativas entre ambas áreas. Las actividades de comportamiento registradas por las palomas fueron de descanso, de mantenimiento del plumaje, de vuelo, alimentación, baños de sol y elección de lugares donde posarse. Las actividades se producen en lugares como tejados altos y aleros de edificios en zonas urbanas y tejados y aleros de balcones en zonas suburbanas. El fenotipo de plumaje más abundante para ambas áreas durante el periodo del censo fue Blue bar.
Palabras clave: Columba livia var., paloma doméstica, aves urbanas, Jena, Alemania
Recent Applications of Melanin-like Nanoparticles as Antioxidant Agents
Nanosized antioxidants are highly advantageous in terms of versatility and pharmacokinetics, with respect to conventional molecular ones. Melanin-like materials, artificial species inspired by natural melanin, combine recognized antioxidant (AOX) activity with a unique versatility of preparation and modification. Due to this versatility and documented biocompatibility, artificial melanin has been incorporated into a variety of nanoparticles (NP) in order to give new platforms for nanomedicine with enhanced AOX activity. In this review article, we first discuss the chemical mechanisms behind the AOX activity of materials in the context of the inhibition of the radical chain reaction responsible for the peroxidation of biomolecules. We also focus briefly on the AOX properties of melanin-like NP, considering the effect of parameters such as size, preparation methods and surface functionalization on them. Then, we consider the most recent and relevant applications of AOX melanin-like NPs that are able to counteract ferroptosis and be involved in the treatment of important diseases that affect, e.g., the cardiovascular and nervous systems, as well as the kidneys, liver and articulations. A specific section will be dedicated to cancer treatment, since the role of melanin in this context is still very debated. Finally, we propose future strategies in AOX development for a better chemical understanding of melanin-like materials. In particular, the composition and structure of these materials are still debated, and they present a high level of variability. Thus, a better understanding of the mechanism behind the interaction of melanin-like nanostructures with different radicals and highly reactive species would be highly advantageous for the design of more effective and specific AOX nano-agents
Photoluminescence-Based Techniques for the Detection of Micro- and Nanoplastics
The growing numbers related to plastic pollution are impressive, with ca. 70 % of produced plastic (>350 tonnes/year) being indiscriminately wasted in the environment. The most dangerous forms of plastic pollution for biota and human health are micro- and nano-plastics (MNPs), which are ubiquitous and more bioavailable. Their elimination is extremely difficult, but the first challenge is their detection since existing protocols are unsatisfactory for microplastics and mostly absent for nanoplastics. After a discussion of the state of the art for MNPs detection, we specifically revise the techniques based on photoluminescence that represent very promising solutions for this problem. In this context, Nile Red staining is the most used strategy and we show here its pros and limitations, but we also discuss other more recent approaches, such as the use of fluorogenic probes based on perylene-bisimide and on fluorogenic hyaluronan nanogels, with the added values of biocompatibility and water solubility
Rational Design of Triplet Sensitizers for the Transfer of Excited State Photochemistry from UV to Visible
Are psychological status and trust in information related to vaccine hesitancy during COVID-19 pandemic? A latent class and mediation analyses in Italy
Despite the recognized benefits of the COVID-19 vaccination, vaccine hesitancy (VH) remains one of the biggest challenges of the mass vaccination campaign. Most studies investigating VH determinants focused on socio-demographics and direct relationships. In this study, we aimed at: 1) identifying subgroups of people differently affected by the pandemic, in terms of psychological status; 2) investigating the role of psychological status and trust in information as possible mediators of the relationship between individual characteristics and VH. To this purpose, a latent class analysis (LCA) followed by a mediation analysis were carried out on data from a survey conducted in January 2021 on 1011 Italian citizens. LCA identified four different subgroups characterized by a differential psychological impact of the pandemic: the extremely affected (21.1%), the highly affected (49.1%), the moderately affected (21.8%) and the slightly affected (8%). We found that VH decreased with the increase of psychological impact (from 59.3% to 23.9%). In the mediation analysis, past vaccination refusal, age 45-54 years and lower-than-average income, were all indirectly related to higher VH through mistrust in COVID-19 information. Differently, the psychological impact counteracted the greater VH in females, the negative effect of social media among youngest (<35 years) and the negative effect of mistrust in the lower-than-average-income subgroup. Knowledge of psychological profile of hesitant individuals, their level of trust and the sources of information they access, together with their sociodemographic characteristics provides a more comprehensive picture of VH determinants that can be used by public health stakeholders to effectively design and adapt communication campaigns
Pellet analysis evidences flexibility in the diet of Brown Skua (Stercorarius antarcticus) during breeding at Esperanza/Hope Bay (Antarctic Peninsula)
At Esperanza/Hope Bay, Antarctic Peninsula, breeding Brown Skuas (Stercorarius antarcticus) coexist with a breeding colony of Adélie (Pygoscelis adeliae) and Gentoo (P. papua) penguins. Previously, we reported that the principal prey consumed by Brown Skuas was penguin, however, the contribution of marine resources to their diet was high. Besides, the number of conspecifics that compete for this resource gradually increases across the season. This prompted us to enquire into the ecological factors that may promote the use of marine resources during the breeding cycle. For this, during the 2014–2015 and 2015–2016 seasons, 400 regurgitated pellets were collected over the breeding season for different stages in the nesting cycle: incubation, early and late chick rearing. Prey items were classified according to different categories (penguin, fish, mollusk, and crustacea), and the occurrence frequency of each category was determined. As expected, penguins were the main prey consumed, but the occurrence of fish and mollusks increased for both early and late care of chicks. The flexibility in skua foraging behavior may be related to the changing degree of central place forager, and to the fluctuating energy requirements during each breeding stage. Moreover, the conspicuous decline in penguin availability or accessibility induced by intraspecific competition, may represent an alternative driving force in their foraging behavior over the breeding season.Fil: Ibañez, Andres Esteban. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. División Zoología de Vertebrados. Sección Ornitología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; ArgentinaFil: Morales, Lara Mariel. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. División Zoología de Vertebrados. Sección Ornitología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; ArgentinaFil: Torres, D. S.. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. División Zoología de Vertebrados. Sección Ornitología; ArgentinaFil: Borghello, P.. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. División Zoología de Vertebrados. Sección Ornitología; ArgentinaFil: Montalti, Diego. Ministerio de Relaciones Exteriores, Comercio Interno y Culto. Dirección Nacional del Antártico. Instituto Antártico Argentino; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; Argentina. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. División Zoología de Vertebrados. Sección Ornitología; Argentin
A selective ratiometric fluorescent probe for no‐wash detection of PVC microplastic
Microplastics (MP) are micrometric plastic particles present in drinking water, food and the environment that constitute an emerging pollutant and pose a menace to human health. Novel methods for the fast detection of these new contaminants are needed. Fluorescence‐based detection exploits the use of specific probes to label the MP particles. This method can be environmentally friendly, low‐cost, easily scalable but also very sensitive and specific. Here, we present the synthesis and application of a new probe based on perylene‐diimide (PDI), which can be prepared in a few minutes by a one‐pot reaction using a conventional microwave oven and can be used for the direct detection of MP in water without any further treatment of the sample. The green fluorescence is strongly quenched in water at neutral pH because of the formation dimers. The ability of the probe to label MP was tested for polyvinyl chloride (PVC), polyethylene (PE), polyethylene terephthalate (PET), polypropylene (PP), polystyrene (PS), poly methyl methacrylate (PMMA) and polytetrafluoroethylene (PTFE). The probe showed considerable selectivity to PVC MP, which presented an intense red emission after staining. Interestingly, the fluorescence of the MP after labeling could be detected, under excitation with a blue diode, with a conventional CMOS color camera. Good selectivity was achieved analyzing the red to green fluorescence intensity ratio. UV– Vis absorption, steady‐state and time‐resolved fluorescence spectroscopy, fluorescence anisotropy, fluorescence wide‐field and confocal laser scanning microscopy allowed elucidating the mechanism of the staining in detail
La colección de aves marinas de Tierra del Fuego, Antártida e Islas del Atlántico Sur del Museo de La Plata.
Solid phase microextraction techniques used for gas chromatography: A review
In the last decade, the development and adoption of greener and sustainable microextraction techniques have been proved to be an effective alternative to classical sample preparation procedures. In this review, 10 commercially available solid-phase microextraction systems are presented, with special attention to the appraisal of their analytical, bioanalytical, and environmental engineering. This review provides an overview of the challenges and achievements in the application of fully automated miniaturized sample preparation methods in analytical laboratories. Both theoretical and practical aspects of these environment-friendly preparation approaches are discussed. The application of chemometrics in method development is also discussed. We are convinced that green analytical chemistry will be really useful in the years ahead. The application of cheap, fast, automated, clever , and environmentally safe procedures to environmental, clinical, and food analysis will improve significantly the quality of the analytical data
Liquid phase microextraction techniques combined with chromatography analysis: A review
Sample pretreatment is the first and the most important step of an analytical procedure. In routine analysis, liquid-liquid microextraction (LLE) is the most widely used sample pre-treatment technique, whose goal is to isolate the target analytes, provide enrichment, with cleanup to lower the chemical noise, and enhance the signal. The use of extensive volumes of hazardous organic solvents and production of large amounts of waste make LLE procedures unsuitable for modern, highly automated laboratories, expensive, and environmentally unfriendly. In the past two decades, liquid-phase microextraction (LPME) was introduced to overcome these drawbacks. Thanks to the need of only a few microliters of extraction solvent, LPME techniques have been widely adopted by the scientific community. The aim of this review is to report on the state-of-the-art LPME techniques used in gas and liquid chromatography. Attention was paid to the classification of the LPME operating modes, to the historical contextualization of LPME applications, and to the advantages of microextraction in methods respecting the value of green analytical chemistry. Technical aspects such as description of methodology selected in method development for routine use, specific variants of LPME developed for complex matrices, derivatization, and enrichment techniques are also discussed
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