Large-Eddy Simulation closures of passive scalar turbulence: a systematic approach

The issue of the parameterization of small scale (``subgrid'') turbulence is addressed in the context of passive scalar transport. We focus on the Kraichnan advection model which lends itself to the analytical investigation of the closure problem. We derive systematically the dynamical equations which rule the evolution of the coarse-grained scalar field. At the lowest-order approximation in $l/r$, $l$ being the characteristic scale of the filter defining the coarse-grained scalar field and $r$ the inertial range separation, we recover the classical eddy-diffusivity parameterization of small scales. At the next-leading order a dynamical closure is obtained. The latter outperforms the classical model and is therefore a natural candidate for subgrid modelling of scalar transport in generic turbulent flows.Comment: 10 LaTex pages, 1 PS figure. Changes: comments added below previous (3.10); Previous (3.16) has been corrected; Minor changes in the conclusion

A nonmonotone GRASP

A greedy randomized adaptive search procedure (GRASP) is an itera- tive multistart metaheuristic for difficult combinatorial optimization problems. Each GRASP iteration consists of two phases: a construction phase, in which a feasible solution is produced, and a local search phase, in which a local optimum in the neighborhood of the constructed solution is sought. Repeated applications of the con- struction procedure yields different starting solutions for the local search and the best overall solution is kept as the result. The GRASP local search applies iterative improvement until a locally optimal solution is found. During this phase, starting from the current solution an improving neighbor solution is accepted and considered as the new current solution. In this paper, we propose a variant of the GRASP framework that uses a new “nonmonotone” strategy to explore the neighborhood of the current solu- tion. We formally state the convergence of the nonmonotone local search to a locally optimal solution and illustrate the effectiveness of the resulting Nonmonotone GRASP on three classical hard combinatorial optimization problems: the maximum cut prob- lem (MAX-CUT), the weighted maximum satisfiability problem (MAX-SAT), and the quadratic assignment problem (QAP)

An Efficient Coded Multicasting Scheme Preserving the Multiplicative Caching Gain

Coded multicasting has been shown to be a promis- ing approach to significantly improve the caching performance of content delivery networks with multiple caches downstream of a common multicast link. However, achievable schemes proposed to date have been shown to achieve the proved order-optimal performance only in the asymptotic regime in which the number of packets per requested item goes to infinity. In this paper, we first extend the asymptotic analysis of the achievable scheme in [1], [2] to the case of heterogeneous cache sizes and demand distributions, providing the best known upper bound on the fundamental limiting performance when the number of packets goes to infinity. We then show that the scheme achieving this upper bound quickly loses its multiplicative caching gain for finite content packetization. To overcome this limitation, we design a novel polynomial-time algorithm based on random greedy graph- coloring that, while keeping the same finite content packetization, recovers a significant part of the multiplicative caching gain. Our results show that the order-optimal coded multicasting schemes proposed to date, while useful in quantifying the fundamental limiting performance, must be properly designed for practical regimes of finite packetization.Comment: 6 pages, 7 figures, Published in Infocom CNTCV 201

Country-of-origin effect and millennials’ wine preferences-a comparative experiment

For wine consumers, the country-of-origin effect still exerts significant influence, even though probably differently from what it was earlier, especially for newer consumer seg-ments. Among these, millennials represent the most interesting segment of the present and future, even though studies on millennials’ behaviour are insidious and newer consumer segments are emerging (Generation Z). This study focuses on this parameter through a comparative analysis of French and Italian wines—first, on the country-of-origin effect on millennials’ wine preferences, and second, on the possibility of managing this influence by adopting a wine marketing mix based on the innovative 4Es model. The outcomes of the ex-periment on 121 millennials, despite the limitations of the study, highlight interesting changes—compared with the wine consumption behaviours of the past—regarding the coun-try-of-origin effect and the possibility of managing it. The results confirm, similar to the lit-erature on the 4Es model, the possibility of wide areas of action for wine educational mar-keting initiatives that can change or enhance the country-of-origin perception

Intellectual capital in nonprofit organizations: a focus on social capital as a marketing enabler

Design/methodology/approach: After a literature review about the intellectual capital (IC) and the social capital (SC) in the non-profit sector (NPS), at either national or international level, the study presents a bibliometric-systematic literature review (B-SLR) of the field in question. Purpose: The research has the aim of exploring whether and how relevant studies about nonprofit organizations (NPOs) have so far investigated the fruitful effects that can be generated by proactive governance, management and marketing of their IC – particularly when considering its extension to SC – with relation to the promotion of corporate reputation. Findings: According to a quantitative (more bibliometric) perspective, the scientific interest on this specific issue has not always been constant and methodical, while three themes (institutional scope, human resources and operational functioning) have so far mostly been analyzed according to a qualitative (and therefore more systematic) perspective. Originality/value: Despite some recent trends aimed at re-evaluating the effect of intangible assets in any organization, there is still some reticence within the NPS to consider the importance of these resources. This orientation also extends to IC, and more specifically to SC, which should now be considered as relevant factors in the creation of value for any socioeconomic organization, both nationally and internationally

Wine tourism as a non-core business strategy for small wineries

In recent years, wineries have been implementing increasingly more wine tourism activities as complementary or supplementary services to enhance their wine products. This paper adopts an inductive research paradigm based on grounded investigation; more specifically, this paper begins with a case study and expands to involve further similar evidence. The findings of this study show that, for wineries, wine tourism represents a fundamental opportunity for communication (institutional and commercial), distribution (as a form of direct channel), and growth (to include tasting, catering, hospitality, and so on). Most importantly, for both scholars and managers, the results of the research highlight that wine tourism can become the main source of the business value, especially in the case of small wineries (an example of which is examined in the case study under analysis). In these situations, however, wine production still characterizes the business because, otherwise, there can be no wine tourism, but wine production is not realistically critical to the business in terms of survival, competitiveness, and development

Gender assessment through three-dimensional analysis of maxillary sinuses by means of Cone Beam Computed Tomography

OBJECTIVE: The availability of a low dose radiation technology such as Cone Beam Computed Tomography (CBCT) in dental practice has increased the number of scans available for forensic purposes. Moreover, specific software allows for three-dimensional (3D) characterization of the maxillary sinuses. This study was performed to determine whether sinus maxillary volumes can be useful to identify gender after validating the use of the Dolphin software as a tool for volumetric estimation of maxillary sinus volumes. PATIENTS AND METHODS: The validation was performed by four different operators measuring the volume of six phantoms, where the real volume was already known. The maxillary sinus volumes of 52 patients (26 males and 26 females) mean age 24.3 were calculated and compared between genders and sagittal skeletal class subdivision. The measurements for patients and phantoms were based on CBCT scans (ILUMA™) processed by Dolphin 3D software. RESULTS: No statistical difference was observed between the real volume and the volume measurements performed by the operators. No statistical difference was found in patient's maxillary sinus volumes between gender. CONCLUSIONS: Based on our results, it is not possible to support the use of maxillary sinuses to discern sexual difference in corpse identification

Application of clinical indexes in ulcerative colitis patients in regular follow-up visit. correlation with endoscopic 'mucosal healing' and implication for management

OBJECTIVE: Ulcerative Colitis (UC) is a chronic inflammatory disease of the colon of unknown etiology. Several clinical indexes have been proposed for UC disease activity evaluation, but none have been properly validated. Moreover, the reference parameter for the scores and their prognostic value is not clear. Mucosal healing has been recently proposed as an important end-point. Aim of the present study was to evaluate the correlation of four clinical indexes with objective diagnostic tools for UC evaluation, the discriminative ability in identifying patients with endoscopic mucosal healing, and to analyze the possible prognostic indication for disease course in 1 year of follow-up. PATIENTS AND METHODS: We analyzed data of 75 patients recorded in regular follow-up visit in IBD clinic at S. Andrea Hospital, Rome, between 2007-2011. We recorded clinical data and lab tests at the time of the visit, and endoscopic/ histological repor ts performed within 1 month. Clinical indexes (Seo' activity index, Simple Clinical Colitis Activity Index, partial Mayo score and Endoscopic-Clinical Correlation Index) were calculated and correlation to endoscopic and histologic activity, and to C-reactive protein increment, was assessed by mean of Spearman's rank correlation. Discriminative ability of the indexes for patients with and without endoscopic mucosal healing was tested by calculation of area under ROC curve (AUC). Patients with low and high clinical scores were compared for number of flares and increment of therapy during 1 year of follow-up. RESULTS: Clinical indexes had a good correlation with endoscopic activity (mean r = 0.73 ± 0.06), a fair correlation with CRP-increment (mean r = 0.55 ± 0.01) and a poor one with histologic activity (mean r = 0.35 ± 0.01). The discriminatory ability of the indexes for endoscopic mucosal healing was good for all the indexes (mean AUC = 0.87 ± 0.05). Patients with high clinical score had more flares and required more frequently increase of therapy at 1 year of follow up compared with patients with low score. CONCLUSIONS: Clinical indexes have a good correlation with endoscopic activity and can discriminate patients with and without mucosal healing. Patients with low and high score have different risk of disease flare and of need to increase therapy at 1 year. Clinical indexes may represent a useful tool for disease assessment in clinical practice in UC outpatients with mildmoderate disease