772 research outputs found
Supersymmetric Construction of W-Algebras from Super Toda and Wznw Theories
A systematic construction of super W-algebras in terms of the WZNW model
based on a super Lie algebra is presented. These are shown to be the symmetry
structure of the super Toda models, which can be obtained from the WZNW theory
by Hamiltonian reduction. A classification, according to the conformal spin
defined by an improved energy-momentum tensor, is dicussed in general terms for
all super Lie algebras whose simple roots are fermionic . A detailed discussion
employing the Dirac bracket structure and an explicit construction of
W-algebras for the cases of , , and are given. The and super conformal algebras are discussed
in the pertinent cases.Comment: 24 page
No evidence of increased fire risk due to agricultural land abandonment in Sardinia (Italy)
Abstract. Different land cover types are related to different levels of fire hazard through their vegetation structure and fuel load composition. Therefore, understanding the relationships between landscape changes and fire behavior is of crucial importance for developing adequate fire fighting and fire prevention strategies for a changing world. In the last decades the abandonment of agricultural lands and pastoral activities has been the major driver of landscape transformations in Mediterranean Europe. As agricultural land abandonment typically promotes an increase in plant biomass (fuel load), a number of authors argue that vegetation succession in abandoned fields and pastures is expected to increase fire hazard. In this short paper, based on 28 493 fires in Sardinia (Italy) in the period 2001â2010, we show that there is no evidence of increased probability of fire ignition in abandoned rural areas. To the contrary, in Sardinia the decreased human impact associated with agricultural land abandonment leads to a statistically significant decrease of fire ignition probability
Improvement of Carrot Stands with Plant Biostimulants and Fluid Drilling
We determined if application of certain naturally occurring compounds would stimulate emergence, growth, and development of carrot (Daucus carota L.). The commercially available biostimulants Agro-Lig, Enersol (humic acids), and Ergostim (folic acid) were added at a concentration of 1.5% (w/v) to Laponite 508 (magnesium sulfate) gel used in fluid drilling. Agro-Lig, Enersol and Ergostim increased carrot emergence \u3e2-fold as measured by number of roots as compared to untreated seed. Number of carrots increased 50% to 75% when biostimulants were incorporated into the gel, compared to fluid-drilled seed without the biostimulants. When biostimulants were applied as a drench over untreated seeds sown conventionally, the average root weight obtained was more than twice that from untreated seeds
Quantifying the network connectivity of landscape mosaics: a graph-theoretical approach
Connectivity determines a large number of ecological functions of the landscape, including seed and animal dispersal, gene flow and disturbance propagation, and is therefore a key to understanding fluxes of matter and energy within land mosaics. Several approaches to quantifying landscape connectivity are possible. Among these, graph theory may be used to represent a landscape as a series of interconnected patches, where flows occur as a result of structural and/or functional patch connectivity. Within this context, we propose the use of a graph-theoretic index (i.e., the Harary index) as a measure of landscape connectivity. Results derived from the analysis of the vegetation map of Palmarola (central Italy) show that, from a statistical and ecological viewpoint, the Harary index may be a better measure of landscape connectivity than more traditional indices derived from transportation geography
Ladder operators for subtle hidden shape invariant potentials
Ladder operators can be constructed for all potentials that present the
integrability condition known as shape invariance, satisfied by most of the
exactly solvable potentials. Using the superalgebra of supersymmetric quantum
mechanics we construct the ladder operators for two exactly solvable potentials
that present a subtle hidden shape invariance.Comment: 9 pages, based on the talk given at International Conference Progress
in Supersymmetric Quantum Mechanics (PSQM03), Valladolid, Spain, 15-19 July,
2003, to appear in a Special Issue of J. Phys. A: Math. Ge
Mandibular reconstruction with bridging customized plate after ablative surgery for ONJ: A multiâcentric case series
Purpose: Computerâaided methods for mandibular reconstruction have improved both functional and morphological results in patients who underwent segmental mandibular resection. The purpose of this study is to evaluate the overlaying of virtual planning in terms of measures of the Computer Assisted Design/Computer Assisted Manufacturing CAD/CAM plate for mandibular reconstruction in patients who are ineligible for the insertion of reconstructing the titanium plate supported by fibular free flap, due to their poor health status, or in the presence of specific contraindications to autologous bone flap harvest. Materials and methods: The retrospective study performed analyzed the results of nine patients. The patients were treated at the Maxillofacial Surgery Unit of Policlinico S. Orsola of Bologna, Italy, and Policlinico San Marco, Catania, Italy, from April 2016 to June 2021. Superimposition between planning and post operative Computed Tomography CT scan was performed to assess the accuracy. Results: All reconstructive procedures were carried out successfully. No microsurgeryârelated complications occurred. In two cases, we had plate misplacement, and in one case, plate exposure that led to plate removal. The average accuracy of the series assessed after CT superimposition, as previously described, was 0.95 mm. Conclusions: Considering that microvascular bone transfer is a highârisk procedure in BRONJ patients, we can conclude that the positioning of a customized bridging mandibular prosthesis (CBMP), whether or not it is associated with a microvascular soft tissue transfer, is a safe technique in terms of surgical outcome and feasibility
Craniofacial osteomas: From diagnosis to therapy
An osteoma is a benign bone lesion with no clear pathogenesis, almost exclusive to the craniofacial area. Osteomas show very slow continuous growth, even in adulthood, unlike other bony lesions. Since these lesions are frequently asymptomatic, the diagnosis is usually made by plain radiography or by a computed tomography (CT) scan performed for other reasons. Rarely, the extensive growth could determine aesthetic or functional problems that vary according to different locations. Radiographically, osteomas appear as radiopaque lesions similar to bone cortex, and may determine bone expansion. Cone beam CT is the optimal imaging modality for assessing the relationship between osteomas and adjacent structures, and for surgical planning. The differential diagnosis includes several inflammatory and tumoral pathologies, but the typical craniofacial location may aid in the diagnosis. Due to the benign nature of osteomas, surgical treatment is limited to symptomatic lesions. Radical surgical resection is the gold standard therapy; it is based on a minimally invasive surgical approach with the aim of achieving an optimal cosmetic result. Reconstructive surgery for an osteoma is quite infrequent and reserved for patients with large central osteomas, such as big mandibular or maxillary lesions. In this regard, computer-assisted surgery guarantees better outcomes, providing the possibility of preoperative simulation of demolitive and reconstructive surgery
Percolation in real Wildfires
This paper focuses on the statistical properties of wild-land fires and, in
particular, investigates if spread dynamics relates to simple invasion model.
The fractal dimension and lacunarity of three fire scars classified from
satellite imagery are analysed. Results indicate that the burned clusters
behave similarly to percolation clusters on boundaries and look more dense in
their core. We show that Dynamical Percolation reproduces this behaviour and
can help to describe the fire evolution. By mapping fire dynamics onto the
percolation models the strategies for fire control might be improved.Comment: 8 pages, 3 figures, epl sytle (epl.cls included
The quest for improving treatment of cancer of unknown primary (CUP) through molecularly-driven treatments: a systematic review
Background: Carcinomas of unknown primary (CUP) account for 3-5% of all malignancy and, despite a reduction in incidence, the overall survival has not improved over the last decade. Chemotherapy regimens have not provided encouraging results. New diagnostic technologies, such as next generation sequencing (NGS), could represent a chance to identify potentially targetable genomic alterations in order to personalize treatment of CUP and provide insights into tumor biology. Methods: A systematic review of studies of patients with CUP, whose tumor specimen was evaluated through a NGS panel, has been performed on June 10th, 2019 according to PRISMA criteria from PubMed, ASCO meeting library and Clinicaltrial.gov. We have identified potentially targetable alterations for which approved/off-label/in clinical trials drugs are available. Moreover, we have included case reports about CUP patients treated with targeted therapies driven by NGS results in order to explore the clinical role of NGS in this setting. Results: We have evaluated 15 publications of which eleven studies (9 full-text articles and 2 abstracts) have analyzed the genomic profiling of CUPs through NGS technology, with different platforms and with different patients cohorts, ranging from 16 to 1,806 patients. Among all these studies, 85% of patients demonstrated at least one molecular alteration, the most frequent involving TP53 (41.88%), KRAS (18.81%), CDKN2A (8.8%), and PIK3CA (9.3%). A mean of 47.3% of patients harbored a potentially targetable alteration for which approved/off-label/in clinical trials drugs were available. Furthermore, we have identified 4 case reports in order to evaluate the clinical relevance of a specific targeted therapy identified through NGS. Conclusions: NGS may represent a tool to improve diagnosis and treatment of CUP by identifying therapeutically actionable alterations and providing insights into tumor biology
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