2,568 research outputs found
PROSYSTEMIN: A HUB OF TOMATO PLANT DEFENSE RESPONSES
Plants live in a complex environment suffering various stress constraints. To counteract stress condition plants have evolved sophisticated defense systems. In tomato plants a key role in defense is played by systemin (Sys), an octadecapeptide, released upon leaf damage from a larger precursor, prosystemin (Prosys). Considering the need to reduce the agro-chemicals we investigated foliar and hydroponic application of Sys to tomato plants that increased both direct and indirect defenses (Chapter 1): treated plants strongly reduce growth and vitality of Spodoptera littoralis larvae also damaging the development of future insect generations. In addition, Sys treated plants reduce leaves colonization of the necrotrophic fungus Botrytis cinerea and have an increased level of attractiveness of natural herbivores antagonists. In order to investigate the molecular mechanism underpinning Prosys' defence activation, a prediction study of protein-protein interactions (PPIs) was done (Chapter 2). More than 16000 interactions were captured from the interactome query and, among them, 98 Prosys direct interactors were catalogued using GO terms. Prosys sub-network evidenced that Prosys links with two large groups of kinases and transcription factors confirming that the precursor is associated with the very early steps of plant stress perception. Prosys PPIs were also investigated in vitro and in vivo (Chapter 3). Affinity Purification Mass Spectrometry (AP-MS) detected more than 300 Prosys interactors, including two molecular partners identified in silico, a heat shock protein 70 (Sl-HSP70-1), which plays a key role in stress responses, and NAD-dependent epimerase\dehydratase (NaDED), likely associated with both sugar and hormonal plant defense signalling. Some PPIs were validated through BiFC that confirmed the interaction with an ATP-dependent clp protease, detected with AP-MS, and with the NaDED, detected both in silico and in vitro. BiFC also confirmed two interactors of the in silico network, MYB transcription factor and a MAP-Kinase. Overall, the results proved that Sys is a very effective plant protectant, and its use could reduce the application of chemical pesticide while Prosys is involved in a large number of interactions possibly due to its ID structure and consequent biological function
Large Peg-Army Maneuvers
Despite its long history, the classical game of peg solitaire continues to
attract the attention of the scientific community. In this paper, we consider
two problems with an algorithmic flavour which are related with this game,
namely Solitaire-Reachability and Solitaire-Army. In the first one, we show
that deciding whether there is a sequence of jumps which allows a given initial
configuration of pegs to reach a target position is NP-complete. Regarding
Solitaire-Army, the aim is to successfully deploy an army of pegs in a given
region of the board in order to reach a target position. By solving an
auxiliary problem with relaxed constraints, we are able to answer some open
questions raised by Cs\'ak\'any and Juh\'asz (Mathematics Magazine, 2000). To
appreciate the combinatorial beauty of our solutions, we recommend to visit the
gallery of animations provided at http://solitairearmy.isnphard.com.Comment: Conference versio
Energy Recovery from the LNG Regasification Process
The global request of natural gas (NG) is continuously increasing, consequently also the regasification of liquefied natural gas (LNG) is becoming a process largely employed. Liquefied natural gas at a temperature of around 113 K at atmospheric pressure has to be regasified for its transportation by pipeline. The regasification process makes the LNG exergy available for various applications, particularly for the production of electrical energy. Different possibilities to exploit the thermal energy released during regasification are available. New plant configurations whose functioning does not constrain the processes of the regasification terminal are proposed. A possible solution is LNG exploitation as a cold source for ocean thermal energy conversion (OTEC) power plants. Electric energy can be produced also by the exploitation of heat released from hot sources, for instance, the condensation heat of power plants by means of consecutive thermodynamic cycles. The rational use of the cold source (LNG) allows the increment of electrical production and growth of the thermodynamic efficiency, with corresponding environmental benefits
The Prediction of Thermal Loads in Building by Means of the EN ISO 13790 Dynamic Model: A Comparison with TRNSYS☆
Abstract The heating and cooling requirements in buildings are primarily dependent on weather conditions and on the physical and geometrical characteristics of the envelope, and secondly on occupant behaviour. Likewise, regarding the electrical loads, in the presence of multi-generation systems that employ also renewable sources, the prediction of heating and cooling load profiles allows a better planning of the production units, with consequent economic benefits. Furthermore, in a future scenario of Smart Grids, a coordinated production of heating and cooling plants with adjacent systems could be achieved. In order to assess the best operational conditions, an estimate of heating and cooling needs is required in home automation systems to minimize or to rationalize the consumption of primary fossil sources, especially in the presence of a district thermal network. Heating and cooling demands in buildings can be determined by simplified calculation models, which must provide consistent results with those obtainable by more sophisticated commercial software, which are difficult to interface in these automation systems. Therefore, the dynamic model 5R1C described in the standard EN ISO 13790 that employs 6 parameters (5 resistances and 1 capacitor) was tested. This model is simple, requires limited computational times and can be implemented with common programming language. The 5R1C model, in function of the envelope characteristics, determines heating and cooling loads of buildings taking into account the effects linked to thermal inertia. Furthermore, if appropriately predicted climate data are provided, the expected load profiles can be obtained. In order to determine advantages, limitations and accuracy of the 5R1C model, a comparison with the TRNSYS software for three different types of buildings was conducted
study of innovative solutions of the building envelope for passive houses in mediterranean areas
Abstract In Mediterranean climate, passive houses have to be designed to contrast overheating, considering the dynamic behaviour of the opaque envelope, the effect of shading devices and free-cooling. These aspects prevail on the use of elevated insulation thickness and large windowed surfaces toward South. Innovative technical solutions involving dry assembled opaque walls with natural materials and the role of thermal inertia combined with free-cooling, are investigated. A reference building with thermal energy requirements lower than 15 kWh/m², both in winter and in summer, was identified analysing the thermal bridges in the structural nodes and the rational exploitation of solar heat gains
The Passive House in Mediterranean Area: Parametric Analysis and Dynamic Simulation of the Thermal Behaviour of an Innovative Prototype☆
Abstract A parametric analysis for an innovative prototype of passive building, located in south Italy and for residential use, has been conducted to evaluate the thermal energy requirements for heating and cooling applications. The investigation was addressed by considering also the aspect of sustainability, by employing natural materials such as dry sand and wood fibre, and the correspondent effects on the energy performances of the envelope. These materials are usually available on site; they increase the building thermal capacity, which represents a crucial aspect for hot climates, and finally could even be reused after building disposal. The construction system based on the completely dry assembling technique makes the exploitation of the mentioned materials possible. The results of the parametric study were obtained by means of the Design Builder dynamic software, by investigating the glazed surfaces, the control of solar radiation and the exploitation of nocturnal free-cooling. A parametric study allowed for optimization of the envelope, by respecting the limit values of 15 kWh/m 2 suggested by the standard passivhaus in its extended formulation for warm climates
statistical analysis of the heating demand in residential buildings located in mediterranean climate and proposals for refurbishment
Abstract The paper deals with the investigation of the heating energy consumptions of a sample of residential buildings located in South Italy. A survey for the collection of data concerning energy performance certificates, characteristics of the building envelopes, air-conditioning plants and real consumptions, was carried out. A statistical analysis aimed at the identification of the main parameters affecting the energy requirements was developed using SPSS software. A multiple regression analysis was applied to obtain a forecasting tool that can be used to identify suitable action strategies for the retrofitting of buildings in the considered area
Void Fraction Near Surfaces Immersed in Fluidized Beds by Heat Transfer Measurements
A semi-empirical model is used to calculate the averaged surface void fraction in fluidized beds, εw, starting from experimental data on surface-to-bed heat transfer coefficient. The model is able to describe the effect of the main process parameters and shows that εw increases with minimum fluidization void fraction and particle Archimedes number
Organic and conventional public food procurement for youth in Italy
Political organisation and policies about school catering and public organic procurement in Italy. The report is produced within the project ―innovative Public Organic food Procurement for Youth‖, iPOPY, and will be updated and revised during the project period (2007-2010)
Real Costs Assessment of Solar-Hydrogen and Some Fossil Fuels by means of a Combustion Analysis
In order to compare solar-hydrogen and the most used fossil fuels, the evaluation of the "external" costs related to their use is required. These costs involve the environmental damage produced by the combustion reactions, the health problems caused by air pollution, the damage to land from fuel mining, and the environmental degradation linked to the global warming, the acid rains, and the water pollution. For each fuel, the global cost is determined as sum of the market price and of the correspondent external costs. In order to obtain a quantitative comparison, the quality of the different combustion reactions and the efficiency of the technologies employed in the specific application sector have to be considered adequately. At this purpose, an entropic index that considers the degree of irreversibility produced during the combustion process and the degradation of surroundings is introduced. Additionally, an environmental index that measures the pollutants released during the combustions is proposed. The combination of these indexes and the efficiency of the several technologies employed in four energy sectors have allowed the evaluation of the total costs, highlighting an economic scenario from which the real advantages concerning the exploitation of different energy carrier are determined
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