Energy Dissipation on Submerged Block Ramps

Block ramps represent structures that produce high energy dissipation and have a unique characteristic of preserving the ecological balance in a river restoration project. The energy dissipation of a block ramp changes with the tailwater level. In this technical note the relative energy dissipation in submerged flow conditions has been investigated. The experiments were conducted at the Hydraulic Laboratory of the University of Pisa, Pisa, Italy on ramps characterized by different block materials, submergence conditions, and ramp slopes. The study shows that the relative energy loss, varying the hydraulic jump location on the ramp, is essentially a function of the scale roughness, the ramp slope, the ratio between the critical water depth, and the ramp height and the ratio between the ramp length and the reduced length in submerged conditions. The differences in energy dissipation for a submerged hydraulic jump in different bed conditions are also investigated.     

Use of NOAA-AVHRR NDVI images for the estimation of dynamic fire risk in Mediterranean areas

Wildfires are a major cause of land degradation in the Mediterranean region due to their frequent recurrence in the same areas. The evaluation of fire risk is therefore of high practical importance, particularly during the summer arid season, when fires are most frequent and harmful. Recent studies have demonstrated that the evaluation of dynamic fire risk can be carried out by the use of remotely sensed images, and specifically of NOAA-AVHRR Normalized Difference Vegetation Index (NDVI) data. This use relies on the sensitivity of the index to vegetation dryness, which is a major predisposing factor for fire occurrence. Several problems, however, remain linked to the spatial variability of the risk in environmentally heterogeneous areas, which requires the application of suitable processing techniques to the low-resolution imagery.The current work reports on the development and testing of different methodologies for estimating dynamic fire risk by the use of NOAA-AVHRR data. The investigation was conducted in Tuscany (Central Italy) using a large archive of fires that occurred in the region and NOAA-AVHRR NDVI data of 16 years (1985-2000). Relying on previous methodological achievements of our group and other research groups, several procedures were tested to extract information related to fire risk from the remotely sensed images. These trials led to define an optimum method which is based on the identification of pixels where the accordance between interyear variations in fire probabilities and NDVI values is maximum. The accuracy of the risk estimates from this optimum method was finally evaluated by a leave-one-out cross-validation strategy. In this way, the performance of the methodology was assessed, together with its potential for operational fire risk monitoring and forecasting in Mediterranean areas.     

Simple Mechanical Model of Curved Beams by a 3D Approach

Starting from three-dimensional (3D) continuum mechanics, a simple one-dimensional model aimed at analyzing the whole static behavior of nonhomogeneous curved beams is proposed. The kinematics is described by four one-dimensional (unknown) functions representing radial, tangential, and out-of-plane displacements of the beam axis, which are due to flexures and extension, and the twist of the cross section due to torsion. The flexural and axial displacements fit with the classical Euler–Bernoulli beam theory of straight beams, and nonuniform torsion is also considered. The relevant elastogeometric parameters have been determined, and the system of governing equilibrium equations is obtained by means of the principle of minimum potential energy. Finally, the general theory is illustrated with examples.     

User Interaction with the Matita Proof Assistant

Matita is a new, document-centric, tactic-based interactive theorem prover. This paper focuses on some of the distinctive features of the user interaction with Matita, characterized mostly by the organization of the library as a searchable knowledge base, the emphasis on a high-quality notational rendering, and the complex interplay between syntax, presentation, and semantics. “We are nearly bug-free” – CSC, Oct. 2005.     

A structure-function-control paradigm for knowledge-based modeling and design of manufacturing workcells

This paper discusses the integration of structural, functional and control knowledge in manufacturing workcell modeling, simulation and design. After an overview of applications of semantic and object-oriented data models in the manufacturing domain, issues relating to the control synthesis for manufacturing workcells are presented. In particular, a data model encompassing functional and control features, along with application domain structural knowledge, is developed. This model assists in explicitly representing the control aspects of engineering design within an object-oriented database and supports a task-level, functionality-driven, manufacturing workcell design. Since manufacturing workcells consist of a number of elements interacting in a complex manner, workcell control design is one of the most difficult steps in the workcell design procedure. Message passage, commonly used in object-oriented databases, provides no explicit modeling of the database behavior. Hence, it can not serve as a tool for the design of system control. On the other hand, Petrinets (PN) have proven successful in describing complex interaction among active agents. This paper will explore the incorporation of Petri nets as a basis for describing application control knowledge within a structure-function-control data model.     

View Definition and Positioning in DOOD Systems

Because there is no difference between derivation rules and view definitions, DOOD systems are the best candidates to support an object-oriented view mechanism. Yet, to combine expressive power (i.e. no restriction on queries defining views), reusability and modeling accuracy (i.e. insertion of views into the generalization hierarchy), and consistency (stability in oid generation) is still an open challenging domain for OO research. This paper is a contribution to improve existing solutions while simplifying the task of users in the view definition process.     

Common whiplash: psychosomatic or somatopsychic?

We have previously demonstrated that gamma/delta T lymphocytes may participate in the host immune response against lung adenocarcinomas. Here we show that, in about one-fourth of human lung cancers, gamma/delta T cells represented a significant proportion of freshly isolated tumor-infiltrating lymphocytes. Moreover, these cells selectively expand in vitro upon culture in the presence of IL-2, thus suggesting a prior activation in vivo. Finally, when we evaluated the expression of heat shock proteins and of a panel of tumor-associated antigens in lung cancers infiltrated by gamma/delta vs. alpha/beta T cells, we found that the former displayed a distinct antigenic pattern, characterized by over-expression of HSP72 and of the 67-kDa high-affinity laminin receptor, which might account for gamma/delta T-cell recognition.     

Movie exposure to smoking cues and adolescent smoking onset: A test for mediation through peer affiliations.

Objective: To determine whether the effect of movie exposure to smoking on adolescent smoking onset is mediated through increased affiliation with peers who smoke. Design: A longitudinal study was conducted with a sample of 5th- 8th graders; persons who were nonsmokers at the baseline assessment (N = 2,614) were followed up 18 months later. Movie exposure to smoking cues was assessed at baseline with a rigorous coding procedure. Main Outcome Measure: A school-based survey and follow-up telephone interview determined whether the participant smoked cigarettes. Results: Longitudinal structural modeling analysis indicated movie-smoking exposure was related to smoking onset both through an indirect effect involving increased affiliation with peer smokers and through a direct effect. The analysis controlled for demographics, parenting style, rebelliousness and sensation seeking, school performance, parental smoking, and sibling smoking; several of these variables also had mediated or direct effects to smoking onset. Conclusion: The effect of movie exposure on adolescent smoking onset is attributable in part to a social mechanism. Implications of media effects for prevention are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)