Alternative Solution Algorithms for Primal and Adjoint Incompressible Navier-Stokes

Regardless of the specific discretisation framework, the discrete incompressible Navier-Stokes equations present themselves in the form of a non-linear, saddle-point Oseentype system. Traditional CFD codes typically solve the system via the well-known SIMPLE-like algorithms, which are essentially block preconditioners based on Schur complement theory. Due to their “segregated” nature, which reduces to iteratively solving a sequence of linear systems smaller than the full Oseen and better conditioned, traditional SIMPLE-like algorithms have long been considered as the only viable strategy. However, recent progress in computational power and linear solver capabilities has led researchers to develop, for Oseen-type systems (and discrete Navier-Stokes in particular), a number of alternative preconditioners and solution schemes, found to be more efficient than SIMPLE-like strategies but previously deemed practically unfeasible in industrial contexts. The improved efficiency of novel preconditioners entails a) faster, more stable convergence and b) the possibility of driving residuals below more strict tolerances, which is sometimes difficult with SIMPLE due to stagnating behaviour. The second aspect in particular is extremely relevant in the context of adjoint-based optimisation, as evidence suggests that an adjoint system may be affected by convergence issues when the primal flow solution is not well converged. In this work, we present some solution schemes (both traditional and novel) implemented for the Mixed Hybrid Finite Volumes Navier-Stokes solver we introduced in our previous work. Performance, in terms of robustness and convergence properties, is assessed on a series of benchmark test cases. We also turn our attention to the discrete adjoint Navier-Stokes problem itself, which in essence requires solving a linear system similar to the original Oseen and therefore may benefit from the same preconditioning techniques. We show how the primal algorithms are adapted to the adjoint system, and we run a series of adjoint test cases to compare performance of various solution scheme

A Mixed Hybrid Finite Volume Scheme for Incompressible Navier-Stokes

Mixed Virtual Elements (MVE) is an innovative class of discretization schemes allowing solution of PDEs on virtually any mesh; such schemes stem from the idea of building discrete operators mimicking certain key properties of their continuous counterparts. In our previous work [27] we implemented our own 1st-order MVE scheme for convection-diffusion. In the present work, a) we extend such scheme to formally 2nd-order accuracy, b) we deal with the subsequent stability issues, c) we derive a full formally 2nd-order MVE scheme for incompressible steady-state Navier-Stokes, d) we provide a first suggestion for a MVE N-S solution algorithm. Numerical results are reported for benchmark test cases

The mtDNA 15497 G/A polymorphism in cytochrome b in severe obese subjects from Southern Italy.

Background and aim: A large number of mitochondrial DNA (mtDNA) mutations have been implicated in degenerative diseases and aging. The aim of this study was to evaluate whether the 15497 G/A mtDNA polymorphism (G251S) in the cytochrome b subunit of respiratory complex III, which has been associated with obesity-related variables and lipid metabolism in a Japanese population, is associated with severe obesity also in adult Caucasians from southern Italy. Methods and results: Unrelated severely obese patients (n Z 317; BMI > 40 kg/m2) and controls (n Z 217; BMI < 25 kg/m2) from Southern Italy were genotyped by allelic discrimination TaqMan assay for the 15497 G/A mtDNA polymorphism. In obese patients fasting serum total cholesterol, triglycerides, HDL-cholesterol and glucose were measured enzymatically and sitting blood pressure and heart rate were also collected. Mean levels of total cholesterol, triglycerides and glucose were below the upper reference limit for healthy subjects. Female obese subjects showed lower levels of blood pressure and heart rate and higher levels of HDL cholesterol than male obese patients (P < 0.001). All the control subjects and 315/317 severely obese patients were homozygous for the G allele (wild type), whereas only 2/317, were females homozygous for the A allele. Conclusions: The mtDNA 15497 G/A polymorphism in cytochrome b was present in 0.6% obese subjects, two females whose lipid parameters and BMI were similar to those of the overall group. Therefore, this mutation may appear to contribute in rare instances to severe obesity but does not explain the majority of cases in our population. A more extensive genetic haplogroup characterization is required to identify associations to obesity in Caucasians

Influence of trichomes on attractiveness and ovipositional preference of Bemisia tabaci (Genn.) B biotype (Hemiptera: Aleyrodidae) on tomato genotypes

Brazil is one of the world's largest tomato producer, but considerable part of the production is lost due to the attack of Bemisia tabaci (Genn.) B biotype. Resistant germoplasm plants can be an important method for B. tabaci control in integrated pest management approaches. The attractiveness and ovipositional preference of B. tabaci for 17 tomato genotypes were evaluated in a free-choice test. Trials were set up in a randomized block design with ten replicates. Each replicate (one tomato plant per pot) was placed in a cage (80 x 50 x 50 cm) and infested with 1,000 adults during four days. Linear correlation tests were applied between the number of insects and eggs and number of trichomes in each tomato genotype. LA716, LA444-1 and PI134418 genotypes were the least attractive, while the 'Santa Clara' was the most attractive; PI134417 trapped the largest number of adults. LA716 genotype (4.1 eggs/leaflet and 2.1 cm²/eggs per leaflet) was the least preferred for whitefly oviposition; NAV1062, 'Fanny', LA1335, 'Santa Clara' and IAC294 were the most preferred genotypes. The glandular trichomes density was negatively correlated with whitefly's attractiveness and oviposition per leaflet and per leaf, and positively with the number of trapped insects. The non-glandular trichomes density was negatively correlated with the number of trapped insects and positively with whitefly's oviposition per cm²/leaflet andper cm²/leaf. LA716 had high antixenosis level (ovipositional nonpreference) toward B. tabaci B biotype related with type IV glandular trichome.Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq

Biological aspects of Bemisia tabaci (Genn.) B biotype (Hemiptera: Aleyrodidae) on six bean genotypes

A mosca-branca é um dos insetos mais prejudiciais à cultura do feijoeiro, devido principalmente à intensa sucção de seiva e à transmissão do vírus do mosaico dourado. O uso de cultivares resistentes ao inseto é uma ferramenta importante no seu controle. Ensaios foram conduzidos em laboratório, avaliando-se aspectos biológicos de Bemisia tabaci biótipo B para os seguintes genótipos de feijoeiro: Arc 3s, Arc 5s, G13028, G11056, Arc 1 e Porrillo 70. As plantas (estágio IV-1) foram infestadas por moscas-brancas durante um dia e os ovos e ninfas foram observados até a emergência dos adultos. A longevidade e a fecundidade dos insetos emergidos também foram avaliadas. Ninfas alimentadas no genótipo Arc 3s (26,5 dias) tiveram o período de desenvolvimento mais longo, seguidas de G11056 (25,9 dias) e G13028 (25,3 dias). Houve um alongamento de 5,5 dias no período de desenvolvimento dos insetos em Arc 3s quando comparado com Porrillo 70. Altas taxas de mortalidade das ninfas nos genótipos Arc 3s e G11056 (94,7 e 83,1%, respectivamente) indicam que tais materiais podem apresentar resistência do tipo não-preferência para alimentação e/ou antibiose. Assim, embora a longevidade e a fecundidade do inseto não tenham sido afetadas quando criado nos genótipos resistentes (Arc 3s, G11056, G13028 e Arc 5s), sugere-se que tais materiais sejam utilizados em programas de melhoramento de feijoeiro visando à resistência a B. tabaci biótipo B.The silverleaf whitefly is one of the most harmful pests that attack bean crops, mainly for extracting large quantities of phloem sap and transmitting the bean golden mosaic virus. Resistant germoplasm plants can be an important method for controlling this pest. The biological aspects of Bemisia tabaci B biotype on bean (Phaseolus vulgaris) genotypes were evaluated. The tests were conducted under laboratory conditions, with the following genotypes: Arc 1, Arc 3s, Arc 5s, G13028, G11056 and Porrillo 70. The bean plants in a stage IV-1 were infested during one day with silverleaf whiteflies. Afterwards the eggs and nymphs were observed until adult emergence. Longevity and fecundity of emerged insects were also evaluated. The longest development time occurred for nymphs fed on Arc 3s genotype (26.5 days), following by G11056 (25.9 days) and G13028 (25.3 days). The development period was 5.5 days longer in Arc 3s when compared with Porrillo 70. Also, the wild genotypes Arc 3s and G11056 showed higher mortality rates (94.7% and 83.1%, respectively), which may suggest antibiosis and/or feeding nonpreference resistance type. For this reason, although longevity and fecundity were not influenced when the whitefly fed on resistant genotypes (Arc 3s, G11056, G13028 and Arc 5s), those genotypes can be used for bean breeding program towards B. tabaci B biotype

Six novel mutations in the proopiomelanocortin and melanocortin receptor 4 genes in severely obese adults living in southern Italy.

BACKGROUND: The genetic characterization of obese individuals could clarify the molecular mechanisms underlying body weight regulation and lead to targeted therapy. Here we report variants of the proopiomelanocortin (POMC) and melanocortin receptor 4 (MC4R) genes detected in severely obese adults living in southern Italy. METHODS: A total of 196 unrelated nondiabetic severely obese individuals [111 females and 85 males; mean (SD) age, 32.2 (11.5) years; mean body mass index, 48.8 (8.1) kg/m(2)] and 100 normal-weight healthy volunteers (34 males and 66 females) entered the study. POMC and MC4R were genotyped by sequencing analysis. Leptin, insulin, glucose, and the lipid profile were measured in fasting serum samples. We used the protein truncation test to verify the stop-codon mutation. Anthropometric measurements, sitting blood pressure, and heart rate were also recorded. RESULTS: Of the obese participants, 1.5% had mutations in POMC exon 3 (new mutations, P231L and E244X; known, R236G) and 2.5% had MC4R mutations (new mutations, W174C, Q43X, S19fsX51, and I317V; known, A175T). These mutations were not present in the controls. Gene polymorphisms were identified in similar percentages of severely obese and nonobese individuals, i.e., respectively, 52.5% and 51% (POMC) and 1% and 2% (MC4R). CONCLUSIONS: We detected 2 new POMC mutations and 4 new MC4R mutations in a large number of severely obese adults living in southern Italy. These mutations, not present in normal-weight individuals, are further evidence that defects in the melanocortin pathway are related to severe obesity

Body composition in Italian and Danish women

Summary The objective of this cross-sectional study was to compare the body composition and fat distribution measured by dual energy X-ray absorptiometry (DPX, Lunar) in different age decades of agematched Danish and Italian women. The subjects comprised 133 healthy Italian women (age 20± 60 years) age-matched to a representative sub-sample of healthy Danish women (n 375). Total and abdominal body fat tissue mass were measured by dual-energy X-ray absorptiometry. Italian women were shorter and fatter compared with age-matched Danish women, but in middle-age, had a less abdominal fat distribution. There was no difference in total body bone mineral density

Nutritional controlled preparation and administration of different tomato purées indicate increase of β-carotene and lycopene isoforms, and of antioxidant potential in human blood bioavailability: A pilot study

The isoforms of lycopene, carotenoids, and their derivatives including precursors of vitamin A are compounds relevant for preventing chronic degenerative diseases such as cardiovascular diseases and cancer. Tomatoes are a major source of these compounds. However, cooking and successive metabolic processes determine the bioavailability of tomatoes in human nutrition. To evaluate the effect of acute/chronic cooking procedures on the bioavailability of lycopene and carotene isoforms in human plasma, we measured the blood levels of these compounds and of the serum antioxidant potential in volunteers after a meal containing two different types of tomato sauce (rustic or strained). Using a randomized cross-over administration design, healthy volunteers were studied, and the above indicated compounds were determined by HPLC. The results indicate an increased bioavailability of the estimated compounds and of the serum antioxidant potential with both types of tomato purée and the subsequently derived sauces (the increase was greater with strained purée). This study sheds light on the content of nutrient precursors of vitamin A and other antioxidant compounds derived from tomatoes cooked with different strategies. Lastly, our study indicates that strained purée should be preferred over rustic purée

Risk and resilience factors for specific and general psychopathology worsening in people with Eating Disorders during COVID-19 pandemic: a retrospective Italian multicentre study

Purpose: The COVID-19 pandemic restrictions had negative impact on the psychopathology of people with Eating Disorders (EDs). Factors involved in the vulnerability to stressful events have been under-investigated in this population. We aimed to assess which factors contributed to COVID-19-induced worsening in both general and specific psychopathology. Methods: Three-hundred and twelve people with a clinically defined diagnosis of an ED and undergoing a specialist ED treatment in different Italian ED services before the spreading of COVID-19 pandemic filled in an online survey. ED specific and general psychopathology changes after COVID-19 quarantine were retrospectively evaluated. Factors related to COVID-19 concerns (financial condition, fear of contagion, perceived social isolation/support, satisfaction in peer, family or sentimental relationships), illness duration and treatment-related variables (type of treatment provided, type of access to care, satisfaction with therapeutic relationships) were included as predicting factors in a structural equational model, which included latent variables consisting of general and ED psychopathology items as outcomes. Results: A perceived low quality of therapeutic relationships, fear of contagion and increased isolation were positively associated with psychopathology worsening. Reduced satisfaction with family and with friends’ relationships and reduced perceived social support were associated with ED and general symptoms deterioration, respectively. No significant effect emerged for intimate relationships, illness duration, economic condition and type of treatment. Conclusions: This study provides a comprehensive evaluation of clinical variables associated with psychopathological changes during the COVID-19 lockdown period highlighting potential risk and resilience factors and, possibly, informing treatment as well as prevention strategies for EDs. Level of evidence IV: Evidence obtained from multiple time series analysis such as case studies