Weierstrass's criterion and compact solitary waves

Weierstrass's theory is a standard qualitative tool for single degree of freedom equations, used in classical mechanics and in many textbooks. In this Brief Report we show how a simple generalization of this tool makes it possible to identify some differential equations for which compact and even semicompact traveling solitary waves exist. In the framework of continuum mechanics, these differential equations correspond to bulk shear waves for a special class of constitutive laws.Comment: 4 page

Interference and communications among active network applications

This paper focuses on active networks applications and in particular on the possible interactions among these applications. Active networking is a very promising research field which has been developed recently, and which poses several interesting challenges to network designers. A number of proposals for e±cient active network architectures are already to be found in the literature. However, how two or more active network applications may interact has not being investigated so far. In this work, we consider a number of applications that have been designed to exploit the main features of active networks and we discuss what are the main benefits that these applications may derive from them. Then, we introduce some forms of interaction including interference and communications among applications, and identify the components of an active network architecture that are needed to support these forms of interaction. We conclude by presenting a brief example of an active network application exploiting the concept of interaction

Federalismo, regionalismo y descentralización del poder: una perspectiva comparada

[Resumen] El estudio de las tendencias vigentes en el derecho comparado nos revela la pérdida de nitidez de los contornos de la clásica contraposición entre federalismos y regionalismos, tomando en cuenta las parciales sobreposiciones de los modelos en el aspecto organizativo; la contraposición, en cambio, parece volver a adquirir significado en la perspectiva de la inclusión de los sistemas estatales bajo conformación federal o regional en agregaciones de área continental, del tipo representado por la Unión europea y, aunque en un tono bastante menor, por el Mercosur. En efecto, si por un lado la asimetría en las relaciones internas entre el Estado y las unidades regionales parece ser ya un elemento común a los ordenamientos de ambos tipos, por otro lado, con evidencia en Europa, elementos de diferenciación surgen con relación a la participación de los entes sub-estatales en las fases ascendentes y descendentes de producción del derecho comunitario, con una evidente mayor capacidad de adaptación y de búsqueda de espacios de decisión de los sistemas federales. El mismo principio de subsidiariedad tiende a producir efectos de intromisión en el sistema de las fuentes y sobre la relación entre poderes públicos y sociedad civil, con una difundida tendencia a la experimentación de fórmulas de gobernabilidad construidas alrededor de la colaboración entre privados, tercer sector y poderes públicos en la definición y en la implementación de las políticas públicas a nivel local o regional.[Abstract] By studying te trends in comparative law one discovers that the clear distinction between federal and regional systems no longer exists. There is often a partial overlap of the models from an organisational standpoint. This distinction, however, reacquires significance when federal or regional states become part of continental organisations such as the European Union or Mercosur. In fact, if on the one hand it is true to say that asymmetry in the relationship between the central government and the regional entities is a comm on element of both systems, on the other (especially in Europe) there are differences in the way the subnational entities take part in the bottom-up and top-down processes of community law. The member states of federal systems have greater decision- making capacities. Even the principle of subsidariety has a pervasive effect on the system of legal sources and on the relationship between public powers and civil society. A widespread tend is to try out new forms of governance such as the collaboration between the private sector, the third sector and public powers in defining and implementing public policy at local and regional level

Fisica dell'accrescimento

Questo elaborato presenta una descrizione del fenomeno dell’accrescimento di materia su oggetti compatti, esponendo i principali modelli fisici a riguardo. Dopo un’introduzione, in cui viene mostrato come l’accrescimento rappresenti la più importante fonte di energia in astrofisica, si discute nel capitolo 1 il più semplice modello di accresci- mento, dovuto ad Hermann Bondi (1952). Tale modello, proprio per la sua semplicità, risulta molto importante, nonostante trascuri importanti aspetti fisici. Nel capitolo 2 si studia la fisica dei dischi di accrescimento, analizzando sia il caso generale che alcuni casi particolari, come quello stazionario o a viscosità costante. L’elaborato si conclude con una breve analisi dell’emissione termica da parte del disco di accrescimento

HyperSpectral Imaging based approach for monitoring of micro-plastics from marine environment

The possibility to develop a sensor based procedure in order to monitor plastic presence in the marine environment was explored in this work. More in detail, this study was addressed to detect and to recognize different types of microplastics coming from sampling in different sea areas adopting a new approach, based on HyperSpectral Imaging (HSI) sensors. Moreover, a morphological and morphometrical particle characterization was carried by digital image processing. Morphological and morphometrical parameters, combined with hyperspectral imaging information, give a full characterization of each investigated particle, concurring to explain all the transportation, alteration and degradation phenomena suffered by each different polymer particle. Obtained results can represent an important starting point to develop, implement and set up monitor strategies to characterize marine microplastics. Moreover, the procedure developed in this work is fast, not expensive and reliable, making its utilization very profitable

MPC-based humanoid pursuit-evasion in the presence of obstacles

We consider a pursuit-evasion problem between humanoids in the presence of obstacles. In our scenario, the pursuer enters the safety area of the evader headed for collision, while the latter executes a fast evasive motion. Control schemes are designed for both the pursuer and the evader. They are structurally identical, although the objectives are different: the pursuer tries to align its direction of motion with the line- of-sight to the evader, whereas the evader tries to move in a direction orthogonal to the line-of-sight to the pursuer. At the core of the control architecture is a Model Predictive Control scheme for generating a stable gait. This allows for the inclusion of workspace obstacles, which we take into account at two levels: during the determination of the footsteps orientation and as an explicit MPC constraint. We illustrate the results with simulations on NAO humanoids

Effects of field inoculation with VAM and bacteria consortia on root growth and nutrients uptake in common wheat

This study investigated the effects of a commercial biofertilizer containing the mycorrhizal fungus Rhizophagus irregularis and the diazotrophic N-fixing bacterium Azotobacter vinelandii on root and shoot growth, yield, and nutrient uptake in common wheat (Triticum aestivum L.) in order to improve the sustainable cultivation of this widespread crop. The trials were carried out in controlled conditions (rhizoboxes) and in open fields over two years to investigate the interaction between inoculation and three doses of nitrogen fertilization (160, 120 and 80 kg ha1) in a silty-loam soil of the Po Plain (NE Italy). In rhizoboxes, efficient root colonization by R. irregularis was observed at 50 days after sowing with seed inoculation, together with improved root tip density and branching (+~30% vs. controls), while the effects of post-emergence inoculation by soil and foliar spraying were not observable at plant sampling. In the open, field spraying at end tillering significantly increased the volumetric root length density (RLD, +22% vs. controls) and root area density (+18%) after about two months (flowering stage) in both years under medium and high N fertilization doses, but not at the lowest N dose. In absence of inoculation, RLD progressively decreased with increased N doses. Inoculation had a negligible effect on grain yield and N uptake, which followed a typical N dose-response model, while straw Zn, P, and K concentrations were seldom improved. It is concluded that medium-high N fertilization doses are required to achieve the target yield and standards of quality (protein contents) in wheat cultivation, while the use of this mixed VAM-PGPR biofertilizer appears to be a sustainable mean for minimizing the adverse effects of chemical N fertilizers on root expansion and for improving the uptake of low-mobility nutrients, which has potentially relevant environmental benefits

Estado de Derecho, Estado Autonómico y Energías Renovables en Italia

Este artículo describe la evolución de la situación normativa y factual de las energías renovables en el ordenamiento italiano - La dependencia energética del extranjero debido a falta de materias primas clásicas ha influido sobre el desarrollo del sector hídrico, del geotérmico y de las bioenergías, mientras que el eólico y el fotovoltaico han encontrado obstáculos en la sensibilidad de las poblaciones locales hacia las temáticas del medio-ambiente - El sector de la energía atómica conoció un desarrollo vivaz y precoz hasta la mitad de los años '80, cuando varios referéndums populares abrogaron las normas concernientes localización y construcción de las centrales. Desde entonces el ordenamiento italiano solo se ha ocupado del desmantelamiento de las plantas existentes. This article describes the evolution of the Italian legal and factual framework concerning renewable energies. The strong dependence on foreign sources, caused by the lack of carbon and petrol has influenced the development of the hydric sector, of geothermical energies and bionergies. Wind and photovoltaic energies have been obstacled by the resistance of the local population towards possible damages to the environment. At the same time, the use of atomic energy was precociously developed in the '60s and '70s, till 1987. At that time, three referenda abrogated the most important provisions concerning localization and construction of atomic plants. Since then, the Italian legal system has dedicated many efforts for the dismantling of existing plants. </p