254 research outputs found

    From Hermite to Humbert polynomials

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    We use the multivariable Hermite polynomials to derive integral representations of Chebyshev and Gegenbauer polynomials. It is shown that most of the properties of these classes of polynomials can be deduced in a fairly straightforward way from this representation, which proves a unifying framework for a large body of polynomial families, including forms of the Humbert and Bessel type, which are a natural consequence of the point of view developed in this paper

    Fungal endophytes affect plant response to leaf litter with contrasting chemical traits

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    Abstract Plant litter decomposition is a crucial process of nutrient cycling within ecosystems. However, many studies have shown that, apart from its several beneficial effects, organic matter decomposition can be disadvantageous to seed germination, seedling growth, and physiological activity of plants. Litter decomposition was reported to affect both plants and their associated soil microbial communities. The aim of this work was to test the relationships between seed-associated endophytic fungi on the either positive or negative plant's response to different litter types. Leaf material of four species was collected and used in a decomposition experiment inside a growth chamber for 120 days. The plant growth experiment was set in a greenhouse using Trifolium repens and Triticum durum with and without their associated endophytic fungi in the presence of the different litter species at two decay levels (fresh litter and after 120 days of decomposition). Results demonstrated that fresh litter exerted a strong inhibition effect on the plant total biomass when compared to decomposed litter. Moreover, seed-associated endophytic fungi enhanced the inhibitory effect of litter in the observed experimental conditions. The removal of seed-associated endophytic fungi improved the capacity of tested plants to resist to litter inhibitory effect

    Intravitreal triamcinolone, bevacizumab and pegaptanib for occult choroidal neovascularization.

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    PURPOSE: To evaluate best-corrected visual acuity (BCVA) and foveal thickness (FT) changes in occult subfoveal choroidal neovascularization (CNV) from age-related macular degeneration (AMD) after intravitreal bevacizumab (IVB, 1.25 mg/0.05 ml), pegaptanib (IVP, 0.3 mg/0.09 ml) and triamcinolone acetonide (IVTA, 4 mg/0.1 ml) injected on an as needed basis. METHODS:   Retrospective, interventional, comparative study. BCVA (Early Treatment Diabetic Retinopathy Study LogMAR) and FT by optical coherence tomography (OCT) were evaluated during 12 months from first treatment. Patients were retreated if signs of neovascular activity were still present on angiography or OCT. RESULTS: Forty-eight eyes received IVB, 43 eyes received IVP, 52 eyes received IVTA. BCVA and FT at baseline were 1.22 ± 0.49 LogMAR and 410.2 ± 41.83 μm in the IVB group, 1.25 ± 0.43 LogMAR and 452.3 ± 44.83 μm in the IVP group and 1.31 ± 0.4 LogMAR and 456.6 ± 48.27 μm in the IVTA group. BCVA and FT improved in the three groups during follow-up. A significantly greater improvement of BCVA was present at month-3, month-6 and at month-12 in the IVB and IVP groups (p = 0.01). Improvement of FT was greater in the IVTA group at month-3 (p = 0.02), while it was greater in the anti-Vascular Endothelial Growth Factor (VEGF) groups at month-6 and month-12 (p = 0.01). A postoperative increase of intraocular pressure was detected in 9/52 (17.3%) eyes treated with IVTA, and in two cases it was resistant to topical therapy. CONCLUSION:   Intravitreal injection of anti-VEGF drugs administered on an as needed basis for AMD-related occult CNVs provided functional and anatomic improvement during 12 months of follow-up

    Biochar as plant growth promoter: Better off alone or mixed with organic amendments?

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    Biochar is nowadays largely used as a soil amendment and is commercialized worldwide. However, in temperate agro-ecosystems the beneficial effect of biochar on crop productivity is limited, with several studies reporting negative crop responses. In this work, we studied the effect of 10 biochar and 9 not pyrogenic organic amendments (NPOA), using pure and in all possible combinations on lettuce growth (Lactuca sativa). Organic materials were characterized by 13C-CPMAS NMR spectroscopy and elemental analysis (pH, EC, C, N, C/N and H/C ratios). Pure biochars and NPOAs have variable effects, ranging from inhibition to strong stimulation on lettuce growth. For NPOAs, major inhibitory effects were found with N poor materials characterized by high C/N and H/C ratio. Among pure biochars, instead, those having a low H/C ratio seem to be the best for promoting plant growth. When biochars and organic amendments were mixed, non-additive interactions, either synergistic or antagonistic, were prevalent. However, the mixture effect on plant growth was mainly dependent on the chemical quality of NPOAs, while biochar chemistry played a secondary role. Synergisms were prevalent when N rich and lignin poor materials were mixed with biochar. On the contrary, antagonistic interactions occurred when leaf litter or woody materials were mixed with biochar. Further research is needed to identify the mechanisms behind the observed non-additive effects and to develop biochar-organic amendment combinations that maximize plant productivity in different agricultural systems

    Evaluation of salivary matrix metalloproteinase (MMP-8) in periodontal patients undergoing non-surgical periodontal therapy and mouthwash based on ozonated olive oil: A randomized clinical trial

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    Background: Extracellular matrix metalloproteinases (MMPs) play a pivotal role in the damage to the periodontal tissue in patients with periodontitis. Scaling and root planning (SRP) attempt to control the plaque amount and consequentially reduce the bacterial load. Non-surgical periodontal treatment could be integrated with drug therapy and physiotherapy procedures such as ozone therapy. The aim of this study was to evaluate in a cohort of patients with a diagnosis of periodontitis: (1) the efficacy of non-surgical periodontal therapy assisted by the use of ozonated olive oil-based mouthwash on salivary metalloproteinase (MMP-8) and (2) the reduction of periodontal indices. Methods: Ninety-six subjects with a diagnosis of periodontitis were enrolled in this study and randomly assigned to the study group (SRP + mouthwash) or control group (SRP). The study duration was 3 months. Data on MMP-8, plaque index (PI), bleeding on probing (BoP) and probing pocket depth (PPD) were recorded at T0, T1 (14 days), T2 (1 month) and T3 (6 months). Group differences were assessed using Student’s t-test for independent samples. Results: A significant improvement in PI, BoP, PPD and salivary MMP-8 levels was observed in both groups. An analysis of differences in relative changes of indices revealed the efficacy of ozonated olive oil in decreasing MMP-8 level. Simultaneously, it slowed the decrease of BoP index. Conclusions: Scaling and root plaining with the aid of ozonated olive oil mouthwash were found to be more effective on salivary MMP-8 reduction than scaling and root plaining alone

    Topography modulates near-ground microclimate in the Mediterranean Fagus sylvatica treeline

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    Understanding processes controlling forest dynamics has become particularly important in the context of ongoing climate change, which is altering the ecological fitness and resilience of species worldwide. However, whether forest communities would be threatened by projected macroclimate change or unaffected due to the controlling effect of local site conditions is still a matter for debate. After all, forest canopy buffer climate extremes and promote microclimatic conditions, which matters for functional plant response, and act as refugia for understory species in a changing climate. Yet precisely how microclimatic conditions change in response to climate warming will depend on the extent to which vegetation structure and local topography shape air and soil temperature. In this study, we posited that forest microclimatic buffering is sensitive to local topographic conditions and canopy cover, and using meteorological stations equipped with data-loggers we measured this effect during 1 year across a climate gradient (considering aspect as a surrogate of local topography) in a Mediterranean beech treeline growing in contrasting aspects in southern Italy. During the growing season, the below-canopy near-ground temperatures were, on average, 2.4 and 1.0 °C cooler than open-field temperatures for south and north-west aspects, respectively. Overall, the temperature offset became more negative (that is, lower under-canopy temperatures at the treeline) as the open-field temperature increased, and more positive (that is, higher under-canopy temperatures at the treeline) as the open-field temperature decreased. The buffering effect was particularly evident for the treeline on the south-facing slope, where cooling of near-ground temperature was as high as 8.6 °C for the maximum temperature (in August the offset peaked at 10 °C) and as high as 2.5 °C for the average temperature. In addition, compared to the south-facing slope, the northern site exhibited less decoupling from free-air environment conditions and low variability in microclimate trends that closely track the free-air biophysical environment. Although such a decoupling effect cannot wholly isolate forest climatic conditions from macroclimate regional variability in the south-facing treeline, it has the potential to partly offset the regional macroclimatic warming experienced in the forest understory due to anthropogenic climate change

    La valutazione delle deformazioni del suolo nella piana di Venafro mediante l’elaborazione di dati PSInSar, morfo-strutturali e stratigrafici

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    I bacini intramontani dell’Appennino centro-meridionale sono soggetti, sin dalla loro genesi (Pleistocene inferiore), a deformazioni del suolo, la cui non uniforme distribuzione e la cui diversa entità sono una risposta all’attività di faglie, intersecanti e bordanti le pianure, e al costipamento differenziale dei depositi costituenti le successioni sedimentarie di riempimento. Al fine di valutare la distribuzione spaziale dei movimenti verticali e le relative velocità, e di interpretarne correttamente le cause, è stato affrontato uno studio multidisciplinare che ha previsto l’elaborazione di dati radar con tecnica PSInSAR, lo studio geomorfologico e strutturale e l’analisi stratigrafica di dati di sottosuolo della piana di Venafro, ampia depressione tettonica interposta tra i M. delle Mainarde-M. di Venafro ed i M. del Matese e drenata dal F. Volturno. L’interpolazione dei dati PS, effettuata in ambiente GIS, riferita a due intervalli di tempo, 1995–2000 (ERS) e 2003–2008 (ENVISAT) ha permesso di valutare i ‘cumulative vertical displacements’ (mm), i ‘displacement rates’ (mm/a) e il ‘gradient field’ dei ‘displacement rates’, consentendo di individuare alcuni settori del bacino che si distinguono per tassi di subsidenza superiori alla media e per comportamento deformativo costante nel tempo. Risulta evidente una correlazione tra la distribuzione spaziale del quadro deformativo di natura interferometrica, lo sviluppo geometrico delle faglie che interessano la piana e la natura litologica del riempimento sedimentario. I valori maggiori di subsidenza si registrano nel settore centrale della piana, probabilmente indotti da un maggiore spessore dei depositi di riempimento, nonché dalla presenza di depositi argillo-sabbiosi poco addensati e più suscettibili al costipamento, così come dalla presenza di alcuni lineamenti tettonici orientati NE-SW e NW-SE. In particolare, i valori maggiori si registrano a valle di una scarpata morfologica, orientata NW-SE, coincidente anche con un importante ‘knick point’ del F. Volturno, oltre che a valle di una faglia, orientata NW-SE (Faglia dell’’Aquae Juliae’), attiva in tempi storici per aver dislocato l’acquedotto romano

    Utilizing digital technologies to promote well-being in university students: the ‘DigiWell’ research protocol

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    The COVID-19 pandemic has significantly impacted the well-being of university students, particularly those in healthcare and medical programs. Psychological interventions rooted in positive psychology have proven effective in enhancing mental health, with online and digital delivery methods proving to be equally viable. This study aims to enhance mental health among Italian university students through digital interventions, including virtual reality, utilizing a stepped care approach. Specific objectives include implementing online positive interventions for students experiencing mild distress (DigiWell_Step 1), evaluating a Virtual-Reality intervention for moderate distress (DigiWell_Step 2), and identifying students experiencing high distress or optimal well-being. Cluster analyses and linear models will assess intervention outcomes. It is anticipated that students undergoing these steps will experience significant improvements in well-being and distress reduction, with sustained benefits at a three-month follow-up. This research contributes to understanding the efficacy of mental health interventions for university students, leveraging digital technologies to enhance accessibility and user engagement. The integration of digital technologies enhances the cost-effectiveness and engagement of interventions delivered through a stepped care approach tailored to the targeted population

    Stratigrafia ed assetto geometrico dell’Unità del Sannio nel settore settentrionale dei monti del Matese

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    New stratigraphic and biostratigraphic data arising from the realization of the Sheet No. 405 "Campobasso" of the new Geological map of Italy (1:50.000 scale - CARG Project) allowed, for the first time in this area, to stratigraphically and cartographically define all the ranges composing the basinal Sannio Unit Auct.. Structural analysis and the chronostratigraphic redefinition of siliciclastic deposits covering the Sannio Unit and the carbonate platform successions of the Matese- Frosolone Units, indicate two main evolutionary stages in the Miocene- Pliocene structuring of this portion of the Southern Apennines. In the first stage, starting before Serravallian times, E-verging contraction affected exclusively the basinal units together with their siliciclastic cover. During the second stage, beginning after early Messinian times, NE-verging compression involved both the basinal Sannio Unit and the Matese-Frosolone Units.UnpublishedISPRA - Roma, Italy2.2. Laboratorio di paleomagnetismorestricte

    Monomiality principle, Sheffer-type polynomials and the normal ordering problem

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    We solve the boson normal ordering problem for (q(a)a+v(a))n(q(a^\dag)a+v(a^\dag))^n with arbitrary functions q(x)q(x) and v(x)v(x) and integer nn, where aa and aa^\dag are boson annihilation and creation operators, satisfying [a,a]=1[a,a^\dag]=1. This consequently provides the solution for the exponential eλ(q(a)a+v(a))e^{\lambda(q(a^\dag)a+v(a^\dag))} generalizing the shift operator. In the course of these considerations we define and explore the monomiality principle and find its representations. We exploit the properties of Sheffer-type polynomials which constitute the inherent structure of this problem. In the end we give some examples illustrating the utility of the method and point out the relation to combinatorial structures.Comment: Presented at the 8'th International School of Theoretical Physics "Symmetry and Structural Properties of Condensed Matter " (SSPCM 2005), Myczkowce, Poland. 13 pages, 31 reference
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