Semantically reliable multicast: current status and future work

In multicast communication systems, a single perturbed recipient can drastically affect the performance of a complete group of processes. One way to alleviate this problem is to weakeri reliability requirements by aliowing some messages to be omitted. We propose a multicast service that exploits semantic knowledge to select which messges can be omitted without compromising the application's correctness. This service is basecf on the concept of message obsolescence: A message becomes obsolete when its content is overwritten or implicitly conveyed by a subsequent message. Besides summarizing initial research results [10] showing that message obsolescence can be expressed in a generic way imd can be used to achieve a higher stable throughput, this text advances a definition of the service and outlines our current research directions

Reducing the cost of group communication with semantic view synchrony

View Synchrony (VS) is a powerful abstraction in the design and implementation of de- pendable distributed systems. By ensuring that processes deliver the same set of messages in each view, it allows them to maintain consistency across membership changes. However, experience indicates that it is hard to combine strong reliability guarantees as offered by VS with stable high performance. In this paper we propose a novel abstraction, Semantic View Synchrony (SVS), that exploits the application's semantics to cope with high throughput applications. This is achieved by allowing some messages to be dropped while still preserving consistency when new views are installed. Thus, SVS inherits the elegance of view synchronous communi- cation. The paper describes how SVS can be implemented and illustrates its usefulness in the context of distributed multi-player games

Semantically reliable multicast protocols

Reliable multicast protocols can strongly simplify the design of distributed applications. However it is hard to sustain a high multicast throughput when groups are large and heterogeneous. In an attempt to overcome this limitation, previous work has focused on weakening reliability properties. The authors introduce a novel reliability model that exploits semantic knowledge to decide in which specific conditions messages can be purged without compromising application correctness. This model is based on the concept of message obsolescence: a message becomes obsolete when its content or purpose is overwritten by a subsequent message. We show that message obsolescence can be expressed in a generic way and can be used to configure the system to achieve higher multicast throughput.Supported by the 234/J4 Franco/Portuguese Grant and by Praxis/ C/ EEI/ 12202/ 1998, TOPCO

The impact of artificial intelligence on audit profession

There is an expectation that the introduction of artificial intelligence (AI) will bring about profound changes in the current paradigm of the audit profession, ensuring better reliability and security in the analysis of financial statements. This paper reports the results of a questionnaire survey to ascertain the perceptions of certified auditors, from two Portuguese districts, regarding the impact of artificial intelligence on the audit profession. Findings reveal that the respondents believe that the profession's future depends on the implementation of AI, namely in the efficiency and effectiveness of audit procedures, sampling techniques, cost-benefit relationship and recognizing material distortions.info:eu-repo/semantics/publishedVersio

Adaptive gossip-based broadcast

This paper presents a novel adaptation mechanism that allows every node of a gossip-based broadcast algorithm to adjust the rate of message emission 1) to the amount of resources available to the nodes within the same broadcast group and 2) to the global level of congestion in the system. The adaptation mechanism can be applied to all gossip-based broadcast algorithms we know of and makes their use more realistic in practical situations where nodes have limited resources whose quantity changes dynamically with time without decreasing the reliability.(undefined

Comparing sprinkler and surface irrigation for wheat using multi-criteria analysis: water saving vs. economic returns

Coping with water scarcity using supplemental irrigation of wheat (Triticum aestivum L.) in the semi-arid northeast Syria is a great challenge for sustainable water use in agriculture. Graded borders and set sprinkler systems were compared using multi-criteria analysis. Alternative solutions for surface irrigation and for sprinkler systems were developed with the SADREG and the PROASPER design models, respectively. For each alternative, two deficit irrigation strategies were considered, which were characterized using indicators relative to irrigation water use, yields and water productivity, including farm economic returns. Alternatives were ranked considering two contrasting priorities: economic returns and water saving. A first step in ranking led to a selection of graded borders with and without precise land levelling and of solid set and semi-permanent sprinkler systems. Precise-levelled borders were better for water saving, while non-precise ones ranked higher for economic returns. Semi-permanent set systems have been shown to be better in economic terms and similar to solid set systems when water saving is prioritized. Semi-permanent sprinkler systems rank first when comparing all type of systems together regardless of the considered deficit irrigation strategy. Likely, border irrigation is appropriate when wheat is in rotation with cotton if the latter is surface irrigated. When peace becomes effective, appropriate economic incentives and training for farmers are required to implement innovative approachesinfo:eu-repo/semantics/publishedVersio

Boron nutrition affects membrane leakage and the chemical composition of leaves and fruits of Olea europaea

Boron (B) is an essential microelement for plants, being its deficiency the most frequent micronutrient disorder in olive tree. The main functions of boron are related to cell wall strength and development, membrane function, cell division, fruit and seed development, water relations, sugar transport and hormone development. The study conducted in Bragança (Northeast Portugal), under rainfed conditions, shows that application of Bfertilizer decreased the symptoms of oxidative stress on leaves, both in summer and, with higher extent, in winter. In fact, B-treated trees presented lower electrolyte leakage, in a closely association with higher concentration of total thiols. Moreover, boron increased the concentration of soluble sugars, while decreased the accumulation of starch in both seasons. Meanwhile, total soluble proteins and total phenols levels were higher in Bfertilized plants during the summer period, whereas in winter, after frost events, the concentration of phenols was higher in B-starved trees. The chemical composition of fruits at final harvest revealed that B-supply increases the soluble sugars and the pulp ash content, decreases organic matter and dietary fiber, whilst the crude protein concentration was similar between treatments. Thus, the present study showed that addition of Bfertilizer affects the metabolism of olive tree and give new insights about the effect of boron on plant physiology and biochemistry that will help to refine the improvement in Bfertilizer recommendations for olive growing areas.info:eu-repo/semantics/publishedVersio

A controlled-release fertilizer improved soil fertility but not olive tree performance

The use of a controlled-release fertilizer (CRF) was studied in a traditional rainfed olive grove in a Mediterranean climate where precipitation is very irregular, particularly in the spring. The objective of the study was to assess whether a CRF can improve the olive tree's performance compared to a conventional nitrogen (N) fertilizer (CF), by supplying N gradually and reducing the risk of potential N loss from leaching. The fertilized treatments showed better plant N nutritional status, which resulted in enhanced net photosynthesis and higher leaf concentrations of total soluble sugars, chlorophylls and soluble proteins which, in turn, increased olive yield by 43% in comparison to the unfertilized control. However, in general, no significant differences were found between fertilized treatments in the performance parameters of the trees evaluated, including olive yield. Somewhat unexpectedly, CRF consistently increased the soil organic carbon (C) (29%), kjeldahl-N (75%) and easily extractable glomalin-related soil proteins (EE-GRSP) (60%) and total GRSP (T-GRSP) (122%) compared to the CF. The result was ascribed to a stimulus on the development of herbaceous vegetation and eventually on the activity of the roots of the trees due to the higher soil inorganic-N availability in the autumn. Thus, some soil inorganic-N in the autumn seems to comprise a low risk of leaching, since weeds act as a catch crop and convert this inorganic N into an organic substrate, with potential benefits in the long-term for the agro-system.Doctoral fellowship under the Doctoral Program ‘‘Agricultural Production Chains—from fork to farm’’ (PD/00122/2012) provided by the FCT-Portuguese Foundation for Science and Technology to E. Silva (PD/BD/128274/2017). This research was funded by the Foundation for Science and Technology (FCT, Portugal) and FEDER under Programme PT2020 for financial support to CIMO (UIDB/00690/2020) and CITAB (UIDB/04033/2020). The research was integrated in the activities of the Operational Group ‘‘Novas práticas em olivais de sequeiro: estratégias de mitigação e adaptação às alterações climáticas’’, funded by PT2020 and EAFRD (European Agricultural Fund for Rural Development).info:eu-repo/semantics/publishedVersio

On abundance and phenology of Geophilomorpha (Chilopoda) from Central Amazonian upland forests

The 629 Gcophilomorpha collected within 12 months in the soil (9-7 cm deprh) of a primary upland forest (24 ± 16 individuals/m2 /month on average) and of a secondary upland forest (94 ± 28 ind./m’/month on average) near Manaus (Brazil) comprised 7 and 8 terricolous species respectively. Only 3 species were common to both forest types. In the primary forest, the Schendylidac (3 spp.) represented 57%, and in the secondary forest, the Geophilidac (4 spp.) 82% of all geophilomorphs. The correlation found between rhe monthly abundance of Hyphyd-rophilus adisi (Geophilidae) and rhe humidity of the soil indicared that this eudominant and most probably plurivoltine species of the secondary forest (71 ± 29 ind./m 7monrh on average) is xerophilous. Additional studies showed that rhe Gcophilomorpha represented 0.1—0.3% of rhe total arthropods extracted from rhe soil (0-14 cm depth) in three different upland forest types in Central Amazonia. Between 65% and 91% (48-72 ind./nr/monrh) of the total geophilomorphs were obtained from rhe upper 7 cm of rhe soil during rhe dry season and 44-100% (29-91 ind./m2/monrh) during the rainy season, compared ro the subsoil (7-14 cm depth).Facultad de Ciencias Naturales y Muse