3,724 research outputs found
Polynomial characteristic sets for DFA identification
[EN] We study the order in Grammatical Inference algorithms, and its influence on the polynomial (with respect to the data) identification of languages. This work is motivated by recent results on the polynomial convergence of data-driven grammatical inference algorithms. In this paper, we prove a sufficient condition that assures the existence of a characteristic sample whose size is polynomial with respect to the minimum DFA of the target language. © 2012 Elsevier B.V. All rights reserved.Work partially supported by the Spanish Ministerio de Economia y Competitividad under research project TIN2011-28260-C03-01 and Universidad Politecnica de Valencia grant PAID-2019-06-2011.GarcĂa GĂłmez, P.; LĂłpez RodrĂguez, D.; VĂĄzquez-De-Parga Andrade, M. (2012). Polynomial characteristic sets for DFA identification. Theoretical Computer Science. 448:41-46. https://doi.org/10.1016/j.tcs.2012.04.042S414644
Fungi from a groundwater-fed drinking water supply system in Brazil
Filamentous fungi in drinking water distribution systems are known to (a) block water pipes; (b) cause organoleptic biodeterioration; (c) act as pathogens or allergens and (d) cause mycotoxin contamination. Yeasts might also cause problems. This study describes the occurrence of several fungal species in a water distribution system supplied by groundwater in Recife, Pernambuco, Brazil. Water samples were collected from four sampling sites from which fungi were recovered by membrane filtration. The numbers in all sampling sites ranged from 5 to 207 colony forming units (CFU)/100 mL with a mean value of 53 CFU/100 mL. In total, 859 isolates were identified morphologically, with Aspergillus and Penicillium the most representative genera (37% and 25% respectively), followed by Trichoderma and Fusarium (9% each), Curvularia (5%) and finally the species Pestalotiopsis karstenii (2%). Ramichloridium and Leptodontium were isolated and are black yeasts, a group that include emergent pathogens. The drinking water system in Recife may play a role in fungal dissemination, including opportunistic pathogens.The authors acknowledge the collaboration of the Environmental Sanitation Laboratory CTG, especially Mario Kato who provided TOC analysis. The authors thank Coordenacao de Aperfeicoamento de Pessoal de Nivel Superior-Capes in Brazil for the financial support
Model for resource allocation in decentralized networks using Interaction nets
This article presents the description of a model for allocating resources using Interaction Nets and a strategy for playing public goods. In the description of the model first shows the behavior of the allocation of resources towards the nodes depending on the usefulness of the network and the satisfaction of the agents. Then the generalization of the model with Interaction Nets is described, and a simulation of this behavior is made. It is found that there is an emerging behavior condition in the dynamics of the interaction when assigning resources. To test the model, the interaction of sharing the Internet in an ad hoc network is done. The interaction is shown in the general model obtained
Mild orotic aciduria in UMPS heterozygotes: a metabolic finding without clinical consequences
BACKGROUND: Elevated urinary excretion of orotic acid is associated with treatable disorders of the urea cycle and pyrimidine metabolism. Establishing the correct and timely diagnosis in a patient with orotic aciduria is key to effective treatment. Uridine monophosphate synthase is involved in de novo pyrimidine synthesis. Uridine monophosphate synthase deficiency (or hereditary orotic aciduria), due to biallelic mutations in UMPS, is a rare condition presenting with megaloblastic anemia in the first months of life. If not treated with the pyrimidine precursor uridine, neutropenia, failure to thrive, growth retardation, developmental delay, and intellectual disability may ensue. METHODS AND RESULTS: We identified mild and isolated orotic aciduria in 11 unrelated individuals with diverse clinical signs and symptoms, the most common denominator being intellectual disability/developmental delay. Of note, none had blood count abnormalities, relevant hyperammonemia or altered plasma amino acid profile. All individuals were found to have heterozygous alterations in UMPS. Four of these variants were predicted to be null alleles with complete loss of function. The remaining variants were missense changes and predicted to be damaging to the normal encoded protein. Interestingly, family screening revealed heterozygous UMPS variants in combination with mild orotic aciduria in 19 clinically asymptomatic family members. CONCLUSIONS: We therefore conclude that heterozygous UMPS-mutations can lead to mild and isolated orotic aciduria without clinical consequence. Partial UMPS-deficiency should be included in the differential diagnosis of mild orotic aciduria. The discovery of heterozygotes manifesting clinical symptoms such as hypotonia and developmental delay are likely due to ascertainment bias
Theory and practice in the construction of professional identity in nursing students: A qualitative study
Seasonal variation in the relative dominance of herbivore guilds in an African savanna
African savannas are highly seasonal with a diverse array of both mammalian and invertebrate herbivores, yet herbivory studies have focused almost exclusively on mammals. We conducted a 2-yr exclosure experiment in South Africa's Kruger National Park to measure the relative impact of these two groups of herbivores on grass removal at both highly productive patches (termite mounds) and in the less productive savanna matrix. Invertebrate and mammalian herbivory was greater on termite mounds, but the relative importance of each group changed over time. Mammalian offtake was higher than invertebrates in the dry season, but can be eclipsed by invertebrates during the wet season when this group is more active. Our results demonstrate that invertebrates play a substantial role in savanna herbivory and should not be disregarded in attempts to understand the impacts of herbivory on ecosystems
Resolving fast and slow motions in the internal loop containing stem-loop 1 of HIV-1 that are modulated by Mg(2+) binding: role in the kissingâduplex structural transition
Stem loop 1 (SL1) is a highly conserved hairpin in the 5âČ-leader of the human immunodeficiency virus type I that forms a metastable kissing dimer that is converted during viral maturation into a stable duplex with the aid of the nucleocapsid (NC) protein. SL1 contains a highly conserved internal loop that promotes the kissingâduplex transition by a mechanism that remains poorly understood. Using NMR, we characterized internal motions induced by the internal loop in an SL1 monomer that may promote the kissingâduplex transition. This includes micro-to-millisecond secondary structural transitions that cause partial melting of three base-pairs above the internal loop making them key nucleation sites for exchanging strands and nanosecond rigid-body stem motions that can help bring strands into spatial register. We show that while Mg(2+) binds to the internal loop and arrests these internal motions, it preserves and/or activates local mobility at internal loop residues G272 and G273 which are implicated in NC binding. By stabilizing SL1 without compromising the accessibility of G272 and G273 for NC binding, Mg(2+) may increase the dependence of the kissingâduplex transition on NC binding thus preventing spontaneous transitions from taking place and ensuring that viral RNA and protein maturation occur in concert
Socially and biologically inspired computing for self-organizing communications networks
The design and development of future communications networks call for a careful examination of biological and social systems. New technological developments like self-driving cars, wireless sensor networks, drones swarm, Internet of Things, Big Data, and Blockchain are promoting an integration process that will bring together all those technologies in a large-scale heterogeneous network. Most of the challenges related to these new developments cannot be faced using traditional approaches, and require to explore novel paradigms for building computational mechanisms that allow us to deal with the emergent complexity of these new applications. In this article, we show that it is possible to use biologically and socially inspired computing for designing and implementing self-organizing communication systems. We argue that an abstract analysis of biological and social phenomena can be made to develop computational models that provide a suitable conceptual framework for building new networking technologies: biologically inspired computing for achieving efficient and scalable networking under uncertain environments; socially inspired computing for increasing the capacity of a system for solving problems through collective actions. We aim to enhance the state-of-the-art of these approaches and encourage other researchers to use these models in their future work
Rationale, design and population baseline characteristics of the PERFORM Vascular Project: an ancillary study of the Prevention of cerebrovascular and cardiovascular Events of ischemic origin with teRutroban in patients with a history oF ischemic strOke or tRansient ischeMic attack (PERFORM) trial
<p><b>Purpose</b></p>
<p>PERFORM is exploring the efficacy of terutroban
versus aspirin for secondary prevention in patients with a
history of ischemic stroke or transient ischemic attacks
(TIAs). The PERFORM Vascular Project will evaluate the
effect of terutroban on progression of atherosclerosis, as
assessed by change in carotid intima-media thickness
(CIMT) in a subgroup of patients.</p>
<p><b>Methods and results</b></p>
<p>The Vascular Project includes structural
(CIMT, carotid plaques) and functional (carotid
stiffness) vascular studies in all patients showing at least
one carotid plaque at entry. Expected mean follow-up is
36 months. Primary endpoint is rate of change of CIMT.
Secondary endpoints include emergent plaques and assessment
of carotid stiffness. 1,100 patients are required for
90% statistical power to detect treatment-related CIMT
difference of 0.025 mm. The first patient was randomized
in April 2006.</p>
<p><b>Conclusions</b></p>
<p>The PERFORM Vascular Project will investigate
terutrobanâs effect on vascular structure and function in
patients with a history of ischemic stroke or TIAs.</p>
Search for new phenomena in final states with an energetic jet and large missing transverse momentum in pp collisions at â s = 8 TeV with the ATLAS detector
Results of a search for new phenomena in final states with an energetic jet and large missing transverse momentum are reported. The search uses 20.3 fbâ1 of â s = 8 TeV data collected in 2012 with the ATLAS detector at the LHC. Events are required to have at least one jet with pT > 120 GeV and no leptons. Nine signal regions are considered with increasing missing transverse momentum requirements between Emiss T > 150 GeV and Emiss T > 700 GeV. Good agreement is observed between the number of events in data and Standard Model expectations. The results are translated into exclusion limits on models with either large extra spatial dimensions, pair production of weakly interacting dark matter candidates, or production of very light gravitinos in a gauge-mediated supersymmetric model. In addition, limits on the production of an invisibly decaying Higgs-like boson leading to similar topologies in the final state are presente
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