1,721,168 research outputs found
Quantificare il carbonio fissato dagli alberi
No full textIl recente e grande interesse politico e mediatico intorno al “piantare alberi” è dovuto principalmente all’azione mitigatrice del cambiamento climatico che queste misure si crede siano in grado di portare . Ma quanto sappiamo del reale contributo che queste “nuove foreste” possono apportare? Ecco un contributo che cerca di fare chiarezza su questo aspett
Canopy Exchange and Modification of Nitrogen Fluxes in Forest Ecosystems
Full text linkPurpose of Review We provide an overview of the main processes occurring during the interactions between atmospheric nitrogen and forest canopies, by bringing together what we have learned in recent decades, identifying knowledge gaps, and how they can be addressed with future research thanks to new technologies and approaches.
Recent Findings There is mounting evidence that tree canopies retain a significant percentage of incoming atmospheric nitrogen, a process involving not only foliage, but also branches, microbes, and epiphytes (and their associated micro-environments). A number of studies have demonstrated that some of the retained nitrogen can be assimilated by foliage, but more studies are needed to better quantify its contribution to plant metabolism and how these fluxes vary across different forest types. By merging different approaches (e.g., next-generation sequence analyzes and stable isotopes, particularly oxygen isotope ratios) it is now possible to unveil the highly diverse microbial communities hidden in forest canopies and their ability to process atmospheric nitrogen through processes such as nitrification and nitrogen fixation. Future work should address the contribution of both foliar nitrogen uptake and biological transformations within forest canopies to whole ecosystem nitrogen cycling budgets.
Summary Scientists have studied for decades the role of forest canopies in altering nitrogen derived from atmospheric inputs before they reach the forest floor, showing that tree canopies are not just passive filters for precipitation water and dissolved nutrients. We now have the technological capability to go beyond an understanding of tree canopy itself to better elucidate its role as sink or source of nutrients, as well as the epiphytes and microbial communities hidden within them
Afforestation and CO2 fixation: a few reference figures from scientific research
Full text linkAfforestation is often proposed as one of the most effective nature-based solutions to sequester carbon from the atmosphere, so mitigating the impending climate crisis. As a result, we have witnessed over the last few years a flourishing of projects aimed at planting new forests, particularly in periurban and agricultural settings, without a preliminary scientific discussion of their expected impact. In this contribution, we have therefore tried to summarize the evidence available for Italian settings, so as to define the range of sequestration rates that can be realistically expected. Moreover, we have tried to highlight some of the issues (age effects, single tree vs. stand perspective) that should be taken into account in the debate in order to harmonize results and approaches. Based on available evidence, under mesic conditions and with adequate cures at and after planting, we could realistically expect over the first decades a Net Ecosystem Production of about 3.5 t C ha-1 yr-1, in good agreement with results from other European deciduous tree plantations. Higher rates are definitely possible with fast-growing species (e.g., poplar, eucalypt) and intensive management, not always compatible with the environmental aims of such projects. In conclusion, afforestation can yield important results (also considering the other ecosystem services provided, particularly important in peri-urban and agricultural settings), although far from the C sequestration provided by the protection and sustainable management of existing forests
Seasonal and interannual variability of photosynthetic capacity in relation leaf nitrogen in a deciduos forest plantation in northern Italy
No full textCATS: a bioinformatic tool for automated Cas9 nucleases activity comparison in clinically relevant contexts
Full text linkIntroduction: With the growing number of Cas9 nucleases available to genetic
engineers, selecting the most suitable one for a given application can be
challenging. A major complication arises from the differing protospacer
adjacent motif (PAM) sequence requirements of each Cas9 variant, which
makes direct comparisons difficult. To ensure a fair comparison, it is essential
to identify common target sites that are not biased by the natural genetic
landscape of the chosen target.
Methods: To address this challenge, we developed CATS (Comparing Cas9
Activities by Target Superimposition), a novel bioinformatic tool. CATS
automates the detection of overlapping PAM sequences across different Cas9
nucleases and identifies allele-specific targets, particularly those arising from
pathogenic mutations. One of the key parameters in CATS is the proximity of PAM
sites, which helps minimize sequence composition bias. The tool integrates data
from continuously updated sources and includes ClinVar information to facilitate
the targeting of disease-causing mutations.
Results: CATS significantly reduces the time and effort required for CRISPR/Cas9
experimental design. It streamlines the comparison of Cas9 nucleases with
different PAM requirements, enabling researchers to select the most
appropriate nuclease for their specific target. The tool’s automation, speed,
and user-friendly interface make it accessible to researchers regardless of
their computational expertise.
Discussion: By enabling the identification of overlapping PAMs and allele-specific
targets, CATS supports the implementation of Cas9-based applications in both
research and clinical settings. Its ability to incorporate genetic variants makes it
particularly useful for designing therapeutic approaches that selectively target
mutated alleles while sparing healthy ones. Ultimately, CATS contributes to the
development of more effective and precise genetic therapies
Telerilevamento della concentrazione di azoto fogliare in ecosistemi forestali litoranei
No full textLo studio qui presentato ha lo scopo di testare nuove metodologie per il rilevamento della concentrazione di azoto fogliare (N) a livello di copertura. In particolare sono state messe a confronto due tecniche differenti basate sul remote sensing: la prima basata sulle lunghezze d’onda dello SWIR (Short Wave Infra-Red) e la seconda sul NIR (Near Infra-Red). La possibilità di stimare la concentrazione fogliare di N dalla riflettanza nel NIR è stata dimostrata da recenti studi su foreste temperate e boreali (Ollinger et al., 2008; Hollinger et al., 2009) utilizzando immagini MODIS (Moderate Resolution Imaging Spectroradiometer), poco idonee all’alta variabilità spaziale del territorio italiano. Per ottenere dati SWIR è stato utilizzato un volo aereo MIVIS (Multispectral Infrared and Visible Imaging Spectrometer) effettuato nel giugno 2000 sull’area di studio del Parco Naturale di San Rossore, Pisa (Italia); mentre, per il NIR, si sono utilizzate immagini Landsat 7 ETM+ (Enhanced Thematic Mapper Plus) riprese nello stesso periodo ed interessanti la stessa zona. La riflettanza di copertura stimata da immagini telerilevate è stata poi messa in relazione a rilievi a terra eseguiti sempre nel giugno 2000
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
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