53 research outputs found
Soil Nitrogen Form and Availability affect the role of Arbuscular Mycorrhizal Fungi on Nitrogen Uptake and Nitrogen Recovery in Durum Wheat
No full textThe term Arbuscular Mycorrhizal (AM) is referred to the symbiosis between arbuscular mycorrhizal fungi (AMF) and plant roots. Such symbiosis is the most widespread among plants (two out of three of the all plant taxa) including the majority of crops. AMF belong to the monophyletic subphylum Glomeromycotina which include obligate biotrophs that entirely relay on the host plant for the carbon source. In exchange, AMF provide their host several benefits which have been recognise in mitigation of biotic and abiotic stress, even though the main benefit ascribe to AMF is improving P uptake. However, although the AM symbiosis is considered as a classic example of a mutualistic symbiosis, many factors influence the outcome of this interaction (e.g. fungal and plant species involved in the symbiosis, nutrient availability, etc.), and under certain condition the presence of AMF have been shown to do not influence or depress the plant growth.
Soil N availability is one of the main factors affecting the plant production, and AMF have been shown to be able to transfer N to the host plant. However, the conditions that ruling the uptake and the following transfer of N via AMF to the host plant are still unclear.
Here, durum wheat has been grown with or without AMF inoculum in presence of different N form and availability to study if the amount and the form of soil N affect the outcome of the AM symbiosis.
The experiment was conducted in pot under natural climatic condition. The soil moisture was monitored twice a week with gravimetric methods and additional water was added when the soil moisture reached the 70% threshold of the holding capacity. Three treatments have been compared: 1) native substrate N content (soil Navailability= 0.45 ‰; control); 2) mineral N in form of (NH4)2SO4 applied in equivalent quantity to 75 kg of N ha-1 (N-min); 3) organic N in from of organic matter of Lolium multiflorum applied in equivalent quantity to 6.5 Mg ha-1(N-org). The organic matter was applied before the sowing phase, distributing the fertilizer homogenously in the substrate 5 to 7 cm below the sowing bed. The mineral treatment was applied in two steps: the first application was done 10 days after the emergence (DAE) distributing 2/3 of the total amount, the second was done 50 DAE applying the rest. In each case the fertilizer had a known amount of 15N to monitoring the N fate. Each treatment was replicated 5 times and the experiment was conducted in a completely randomize design. The experiment lasted until the crop reach the flowering phase (75 DAE). At the end of the experiment the biomass was harvested and split in the two parts below and above; the fresh and dry weights were recorded and the total N and 15N content were assayed. The below biomass was used to assay the total root length and the AMF infection. The data were used to determine the plant biomass production, N uptake and N recovery in the plant biomass. The data obtained were analysed in R using a two-way ANOVA. When statistical significance occurred, means were compared using the Tukey’s test. The results, as expected, have shown a marked effect of the fertilizer treatments. In fact, the treatment N-min determined an average increment respect to the control for both above and below ground biomass; while the treatment N-org determined a decrement for both the biomass portion compare to the control. Such trend was consistent for the others variables investigated. As concern the AMF inoculum, on the biomass, the effect was confined to a decrement of the above ground biomass in the N-org treatment, while no significant effect was detected for the same parameter on the others treatments and on the below ground biomass. A strong interaction has been shown between Fertilization and AMF inoculum in N uptake and N recovery. In particular, the presence of AMF determined a decrement of both parameter in the control and N-org, while a marked increase has been detected for both the parameters in the N-min.
In conclusion, the effect of AMF inoculum on total plant biomass was very contained. By contrast, on the others parameters a competitive behaviour for the N source has been shown in a poor-N-environment, while a cooperative behaviour was observed in a reach-N-environment
A Semantic Similarity Measure for the SIMS Framework
No full textThe amount of currently available digital information grows rapidly. Relevant information is often spread over different information sources. An efficient and flexible framework to allow users to satisfy ef- fectively their information needs is required. The work presented in this paper describes SIMS (Semantic Information Management System), a ref- erence architecture for a framework performing semantic annotation, search and retrieval of information from multiple sources. The work pre- sented in this paper focuses on a specific SIMS module, the SIMS Semantic Content Navigator, proposing an algorithm and the related implementa- tion to calculate a semantic similarity measure inside an OWL ontology. This measure is based on ontology structure and on the information pro- vided by attributes and relations that are defined inside the ontology. This work is the result of a collaborative effort between the DINFO (Depart- ment of Computer Science and Engineering) and the research team of En- gineering - Ingegneria Informatica
XPL the eXtensible presentation language
No full textThe last decade has witnessed a growing interest in the development of web interfaces enabling both multiple ways
to access contents and, at the same time, fruition by multiple modalities of interaction (point-and-click, contents reading, voice
commands, gestures, etc.). In this paper we describe a framework aimed at streamlining the design process of multi-channel,
multimodal interfaces enabling full reuse of software components. This framework is called the eXtensible Presentation archi-
tecture and Language (XPL), a presentation language based on design pattern paradigm that keeps separated the presentation
layer from the underlying programming logic. The language supplies a methodology to expedite multimodal interface devel-
opment and to reduce the effort to implement interfaces for multiple access devices, by means of using the same code. This
paper describes a methodology approach based on Visual Design Pattern (ViDP) and Verbal Design Pattern (VeDP), offering
examples of multimodal and multichannel interfaces created with the XPL Editor
SIMS: An Ontology-based Multi-source Knowledge Management System
No full textIn the networked society, innovation projects are carried out through collaboration among wide communities of workers which interact via internet in order to gain knowledge from their collaborators. Moreover as a huge quantity of electronic information is already available on the web, workers look for knowledge items also in web information systems. Organizational web platforms have to support, therefore, cooperation through collaborative applications that integrate both knowledge publishing and sharing. In this paper a technological platform is presented. It enables a uniform and semantic based access to information items belonging to different information systems which are connected to the platform itself through specific modules, called wrappers. SIMS (Semantic Information Management System) is based both on collecting Dublin Core Medatada, which describes information items, structured in a JSR-170 compliant repository, and on the semi-automatic description of the same items based on domain ontologies, expressed in a formal language, such as OWL (Ontology Web Language). A SIMS component, called Semantic Content Navigator, allows users to navigate and access the entire knowledge base managed within the SIMS platform, using Semantic Web technologies. This work is part of the Italian research project DISCoRSO (Distributed Information Systems for CooRdinated Service Oriented interoperability)
XPL, a Presentation Language based on User Interface Design Pattern
No full textThe great diversity of presentations in software applications deals with fulfillment of various type of graphic interface constructions related to different programming Languages. Moreover, in the Internet era html pages play a main role because of the increasing complexity of Web applications. In Software Engineering, the use of design patterns is proven remarkable for the design and reuse of software components. Visual Design. Patterns (ViDP) are useful to define interaction schemas between. user and computer. By the some token, visual design. patterns are useful to incorporate common interfaces of interaction, schemas between user and computer. This paper describes the eXtensible Presentation Language (XPL), a presentation Language based on visual pattern. XPL framework implementation will be discussed in, details and a case study showing the benefits of employing XPL will be presented
Toward a collaborative vocabulary management system
No full textIn the age of knowledge-based economy, the always-growing necessity of an effective means to share concepts and their representation frequently leads to the development of domain specific vocabularies. However, vocabu-laries may fail to capture the real common understanding of a community, mostly because of its low involve-ment in the development phase. The paper gives a first set of considerations about a collaborative approach to vocabulary development and outlines the main issues that such approach would imply. Finally some collabora-tion use cases are proposed for solving some integrity issues that collaboration implicitly entails
An ontology-based multi-source knowledge management system: creating and accessing knowledge items on a collaborative platform
No full textThe eXtensible Dynamic Presentation Manager for content adaptation
No full textHuman Computer Interaction studies deals with systems and tools that are able to improve user experience during interaction with computer. For this purpose, modern web application are expected to supply multimodal and multi-channel access, adaptivity and transcoding features. We will present in this work the eXtensible Dynamic Presentation Manager (XDPM) which is a set of innovative tools that support the eXtensible Presentation Language (XPL) in the adaptation of contents to different working contexts. The adaptation is performed according to the delivery context information which have been formalized by means of a profiler system. A profile holds information about the specific access device, the user preferences and the device working conditions
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