In this paper, we compute the degree of the Kodiyalam polynomials of an ideal in the case where its Rees ring is Cohen—Macaulay and its fiber ring is a domain. We apply this result to some classes of ...polymatroidal ideals.
A novel approach to nonlinear variable-order fractional viscoelasticity Di Paola, M; Alotta, G; Burlon, A ...
Philosophical transactions - Royal Society. Mathematical, Physical and engineering sciences/Philosophical transactions - Royal Society. Mathematical, physical and engineering sciences,
05/2020, Letnik:
378, Številka:
2172
Journal Article
Recenzirano
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This paper addresses nonlinear viscoelastic behaviour of fractional systems with variable time-dependent fractional order. In this case, the main challenge is that the Boltzmann linear superposition ...principle, i.e. the theoretical basis on which linear viscoelastic fractional operators are formulated, does not apply in standard form because the fractional order is not constant with time. Moving from this consideration, the paper proposes a novel approach where the system response is derived by a consistent application of the Boltzmann principle to an equivalent system, built at every time instant based on the fractional order at that instant and the response at all the previous ones. The approach is readily implementable in numerical form, to calculate either stress or strain responses of any fractional system where fractional order may change with time. This article is part of the theme issue 'Advanced materials modelling via fractional calculus: challenges and perspectives'.
The freshwater cnidarian Craspedacusta sowerbii Lankester 1880, has invaded lakes and ponds as well as artificial water bodies throughout the world. The first record in Uruguay corresponding to the ...jellyfish was made in 1961 in two artificial fountains, with no mention of the polyp form. Although local reports of other related polyp species have been made, information on the benthic form of C. sowerbii is lacking. Here we report the finding of live frustules, solitary individuals, medusae and colonies from a natural lagoon in August 2010, allowing us to observe the morphology and behavior of the polyp stage in captivity. In addition, molecular identification and remarks on the potencial path of introduction are presented. This is the first record in Uruguay of both polyp and medusa stages of C. sowerbii in a natural water body, Del Medio Lagoon (Dpto. de Florida), Uruguay.
To evaluate whether two commonly used newer platinum-based regimens offer any advantage over vinorelbine-cisplatin (reference regimen) in response rate for patients with advanced non-small-cell lung ...cancer (NSCLC).
Chemotherapy-naive patients were randomized to receive gemcitabine 1,250 mg/m(2) days 1 and 8 plus cisplatin 75 mg/m(2) day 2 every 21 days (GC arm), or paclitaxel 225 mg/m(2) (3-hour infusion) then carboplatin (area under the concentration-time curve of 6 mg/mL x min), both on day 1 every 21 days (PCb arm), or vinorelbine 25 mg/m(2)/wk for 12 weeks then every other week plus cisplatin 100 mg/m(2) day 1 every 28 days (VC arm).
Six hundred twelve patients were randomized to treatment (205 GC, 204 PCb, and 203 VC). Overall response rates for the GC (30%) and PCb (32%) arms were not significantly different from that of the VC arm (30%). There were no differences in overall survival, time to disease progression, or time to treatment failure. Median survival for the GC, PCb, and VC groups was 9.8, 9.9, and 9.5 months, respectively. Neutropenia was significantly higher on the VC arm (GC 17% or PCb 35% v VC 43% of cycles, P <.001), as was thrombocytopenia on the GC arm (GC 16% v VC 0.1% of cycles, P <.001). Alopecia and peripheral neurotoxicity were most common on the PCb arm, as was nausea/vomiting on the VC arm (P <.05).
Efficacy end points were not significantly different between experimental and reference arms, although toxicities showed differences. These findings suggest that chemotherapy in NSCLC has reached a therapeutic plateau.
For seismic assessment of wind turbines in seismically-active areas, International Standards and Guidelines allow the combination of two uncoupled analyses under environmental and earthquake loads, ...respectively. The separate earthquake response is generally computed including an additional
aerodynamic
damping in the structural model. Although some work has been done to estimate the effectiveness of uncoupled analyses for land-based wind turbines, and determine appropriate levels of aerodynamic damping, to date no similar studies have been carried out for offshore wind turbines. This paper assesses the accuracy of different time-domain implementations of uncoupled analyses for offshore wind turbines, and investigates pertinent levels of aerodynamic damping. The case study is a 5-MW wind turbine, resting on a tripod in intermediate waters.
In this paper the physically-based approach to non-local elasticity theory is introduced. It is formulated by reverting the continuum to an ensemble of interacting volume elements. Interactions ...between adjacent elements are classical contact forces while long-range interactions between non-adjacent elements are modelled as distance-decaying central body forces. The latter are proportional to the relative displacements rather than to the strain field as in the Eringen model and subsequent developments. At the limit the displacement field is found to be governed by an integro-differential equation, solved by a simple discretization procedure suggested by the underlying mechanical model itself, with corresponding static boundary conditions enforced in a quite simple form. It is then shown that the constitutive law of the proposed model coalesces with the Eringen constitutive law for an unbounded domain under suitable assumptions, whereas it remains substantially different for a bounded domain. Thermodynamic consistency of the model also has been investigated in detail and some numerical applications are presented for different parameters and different functional forms for the decay of the long range forces. For simplicity, the problem is formulated for a 1D continuum while the general formulation for a 3D elastic solid has been reported in the appendix.
Using the high symmetry in the geometry of a smooth projective quadric, we construct effectively new families of smooth projective rational surfaces whose nef divisors are regular, and whose ...effective monoids are finitely generated by smooth projective rational curves of negative self-intersection. Furthermore, the Cox rings of these surfaces are finitely generated, the dimensions of their anticanonical complete linear systems are zero, and their nonzero nef divisors intersect positively the anticanonical ones. And in two special cases, we give efficient ways of describing any effective divisor class in terms of the given minimal generating sets for the effective monoids of these surfaces. The ground field of our varieties is algebraically closed of arbitrary characteristic.
ABSTRACT Studies on reproduction in sea turtles are important due to its life cycle, migratory patterns, high juvenile mortality and environmental impacts. This study aimed to analyse ...histomorphometrically gonads of C. mydas from the coastline of the Espírito Santo State, Brazil. Ovaries and testicles were collected between 2014 and 2015 from stranded animals. The material was fixed in formalin 10%, assessed macroscopically and processed for histomorphometrical evaluation. Gonads from 34 individuals were evaluated, twenty-four females and ten males. Macroscopic sexual identification presented 100% accuracy confirmed by histology. Sexual dimorphism was observed in one individual, which was considered as adult (CCL=1.023 m). Microscopy of female gonads revealed predominant previtellogenic follicles; oocyte diameter ranged between 161µm and 750µm and a positive correlation between ovarian length, largest oocyte and CCL was found. In males, autolysis was verified in five individuals. Viable testicles revealed predominant spermatogonia, primary spermatocytes and Sertoli cells in the seminiferous tubules and, Leydig cells and fibroblasts in the stroma. There was a positive correlation between tubular diameter and CCL and testicle length and CCL. Maturation of stromal tissue and a positive correlation between tubular lumen and CCL were also observed. Gonad development is proportional to individual growth.
RESUMO Estudos em reprodução de tartarugas marinhas são importantes devido ao ciclo de vida, ao padrão migratório, à alta mortalidade juvenil e aos impactos ambientais. Objetivou-se analisar histomorfometricamente gônadas de C. mydas no litoral do Espírito Santo. Foram coletados ovários e testículos dessa espécie, entre 2014 e 2015. O material foi fixado em formol a 10% e avaliado macroscopicamente. Em seguida, foi processado para avaliação histomorfométrica. Foram avaliadas gônadas de 34 indivíduos, 24 fêmeas e 10 machos. Verificaram-se 100% de acurácia na identificação sexual à macroscopia, confirmada pela histologia. Observou-se dimorfismo sexual em um macho, que foi considerado adulto (CCC=1,023m). A microscopia dos ovários revelou folículos pré-vitelogênicos, cujos ovócitos apresentaram diâmetro médio entre 161µm e 750µm. Houve correlação positiva entre comprimento ovariano e diâmetro do maior ovócito e CCC. Nos machos, verificou-se autólise em cinco indivíduos. Os testículos viáveis revelaram espermatogônias, espermatócitos primários e células de Sertoli nos túbulos seminíferos, além de células de Leydig e fibroblastos no estroma. Houve correlação positiva entre diâmetro tubular e CCC e comprimento testicular e CCC. Verificou-se maturação do tecido estromal e correlação positiva entre o diâmetro do lúmen tubular e o CCC. Verifica-se que o desenvolvimento das gônadas é proporcional ao crescimento dos indivíduos.
In order to identify rigid body motions of floating offshore structures, output-only techniques are very useful for developing low-cost intermediate-scale experimental activities directly into the ...sea, instead of wave tanks. A crucial parameter, however, is the length of the response records used as input for the identification process, since short records may result in significant loss of accuracy, while long ones may be incompatible with the assumption of stationarity of the sea state. This work presents a sensitivity study conducted on a numerical model of a spar structure, identified by means of Enhanced Frequency Domain Decomposition method. An overview on the efficiency of the method is given for various lengths of response record, along with practical indications on the minimum values acceptable.
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