323,214 research outputs found
Insetti associati ad Arecaceae nelle Marche
No full textLe palme (piante appartenenti alla famiglia delle Arecaceae) sono da tempo diventate un
elemento caratteristico del territorio della regione Marche. L’importanza di questi
elementi vegetali nel paesaggio della fascia costiera si è accresciuta al punto tale che un
tratto della zona litoranea della provincia di Ascoli Piceno è stato denominato “Riviera
delle Palme”. Anche sotto l’aspetto economico la coltivazione in quest’area di alcune
specie di palmizi rappresenta, così come tutto il comparto florovivaistico, una valida
risorsa che ha assunto i connotati di un vero e proprio distretto produttivo. A seguito del
primo rinvenimento nelle Marche di Paysandisia archon Burmeister (Lepidoptera
Castnidae) (Riolo et al., 2004) sono state condotte indagini su palmizi sia in ambiente
urbano sia in ambiente produttivo. Attualmente P. archon è diffusa in alcune aree della
regione sia in ambito urbano sia produttivo ed è stata rinvenuta sulle specie
maggiormente coltivate: Chamaerops humilis L., Trachycarpus fortunei (Hooker)
Wendland, Phoenix canariensis Chabaud e Washingtonia filifera (Linden) Wendland.
In alcuni vivai, su giovani piante di T. fortunei e W. filifera, è stata rilevata la presenza
di Sesamia nonagrioides Lefèbvre (Lepidoptera, Noctuidae), le cui larve nutrendosi a
livello del germoglio apicale, e penetrando in alcuni casi nel rachide fogliare, hanno dato
origine a perforazioni semicircolari del lembo fogliare simili a quelle provocate dalle
giovani larve di P. archon. Nella regione è presente anche Sesamia cretica Lederer
(Riolo et al., 2001) ed ulteriori studi indagheranno se le palme, nelle Marche, sono da
ascrivere tra le sue piante ospiti. Viene segnalato inoltre il rinvenimento di Oryctes
nasicornis (L.) (Coleoptera, Dynastidae) e di Cetonia aurata (L.) (Coleoptera,
Cetoniidae), su esemplari adulti di P. canariensis, le cui larve si sono nutrite della
sostanza organica in decomposizione dei monconi dei rachidi fogliari rimasti sulla pianta
dopo le operazioni di potatura
New hyperbolic 4-manifolds of low volume
No full textWe prove that there are at least two commensurability classes of (cusped, arithmetic) minimal-volume hyperbolic 4-manifolds. Moreover, by applying a well-known technique due to Gromov and Piatetski-Shapiro, we build the smallest known nonarithmetic hyperbolic 4-manifold
Paysandisia archon datasheet
No full textPaysandisia argon data sheet is an online, open access reference work covering recognition, biology, distribution, i mpact, and management of Paysandisia archon
Counting cusped hyperbolic 3-manifolds that bound geometrically
No full textWe show that the number of isometry classes of cusped hyperbolic 3-manifolds that bound geometrically grows at least super-exponentially with their volume, both in the arithmetic and non-arithmetic settings
Hyperbolic Dehn filling in dimension four
No full textWe introduce and study some deformations of complete finite-volume hyperbolic four-manifolds that may be interpreted as four-dimensional analogues of Thurston’s hyperbolic Dehn filling. We construct in particular an analytic path of complete, finite-volume cone four-manifolds Mtthat interpolates between two hyperbolic four-manifolds M0and M1with the same volume 8/3π2. The deformation looks like the familiar hyperbolic Dehn filling paths that occur in dimension three, where the cone angle of a core simple closed geodesic varies monotonically from 0 to 2π. Here, the singularity of Mt is an immersed geodesic surface whose cone angles also vary monotonically from 0 to 2π. When a cone angle tends to 0 a small core surface (a torus or Klein bottle) is drilled, producing a new cusp. We show that various instances of hyperbolic Dehn fillings may arise, including one case where a degeneration occurs when the cone angles tend to 2π, like in the famous figure-eight knot complement example. The construction makes an essential use of a family of four-dimensional deforming hyperbolic polytopes recently discovered by Kerckhoff and Storm
What's Wrong in a Jump? Prediction and Validation of Splice Site Variants
No full textAlternative splicing (AS) is a crucial process to enhance gene expression driving organ-ism development. Interestingly, more than 95% of human genes undergo AS, producing multiple protein isoforms from the same transcript. Any alteration (e.g., nucleotide substitutions, insertions, and deletions) involving consensus splicing regulatory sequences in a specific gene may result in the production of aberrant and not properly working proteins. In this review, we introduce the key steps of splicing mechanism and describe all different types of genomic variants affecting this process (splicing variants in acceptor/donor sites or branch point or polypyrimidine tract, exonic, and deep intronic changes). Then, we provide an updated approach to improve splice variants detection. First, we review the main computational tools, including the recent Machine Learn-ing-based algorithms, for the prediction of splice site variants, in order to characterize how a genomic variant interferes with splicing process. Next, we report the experimental methods to vali-date the predictive analyses are defined, distinguishing between methods testing RNA (tran-scriptomics analysis) or proteins (proteomics experiments). For both prediction and validation steps, benefits and weaknesses of each tool/procedure are accurately reported, as well as sugges-tions on which approaches are more suitable in diagnostic rather than in clinical research. © 2021 by the author. Licensee MDPI, Basel, Switzerland
Compact hyperbolic manifolds without spin structures
No full textWe exhibit the first examples of compact, orientable, hyperbolic manifolds that do not have any spin structure. We show that such manifolds exist in all dimensions
n≥4. The core of the argument is the construction of a compact, oriented, hyperbolic 4–manifold M that contains a surface S of genus 3 with self-intersection 1. The 4–manifold M
has an odd intersection form and is hence not spin. It is built by carefully assembling some right-angled 120–cells along a pattern inspired by the minimum trisection of CP2
.The manifold M is also the first example of a compact, orientable, hyperbolic 4–manifold satisfying either of these conditions:
1) H2(M,Z) is not generated by geodesically immersed surfaces.
2)There is a covering M that is a nontrivial bundle over a compact surface
Convex plumbings in closed hyperbolic 4-manifolds
No full textWe show that every plumbing of disc bundles over surfaces whose genera satisfy a simple inequality may be embedded as a convex submanifold in some closed hyperbolic four-manifold. In particular its interior has a geometrically finite hyperbolic structure that covers a closed hyperbolic four-manifold
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