5,643 research outputs found
Atividade microbiana do solo sob diferentes cultivos irrigados em um Argissolo Vermelho Amarelo distrófico no Submédio São Francisco.
Este trabalho tem por objetivo avaliar a atividade biológica do solo sob diferentes cultivos com uso de irrigação e sua comparação com áreas de Caatinga. As amostras foram coletadas em novembro de 2006 em áreas com cultivo de manga, uva, culturas anuais, banana e em reserva de vegetação natural, no Campo Experimental da Embrapa Semi-¡rido no Distrito Irrigado de Bebedouro
Testing reflection features in 4U 1705-44 with XMM-Newton, BeppoSAX and RXTE in the hard and soft state
We use data of the bright atoll source 4U 1705-44 taken with XMM-Newton,
BeppoSAX and RXTE both in the hard and in the soft state to perform a
self-consistent study of the reflection component in this source. Although the
data from these X-ray observatories are not simultaneous, the spectral
decomposition is shown to be consistent among the different observations, when
the source flux is similar. We therefore select observations performed at
similar flux levels in the hard and soft state in order to study the spectral
shape in these two states in a broad band (0.1-200 keV) energy range, with good
energy resolution, and using self-consistent reflection models. These
reflection models provide a good fit for the X-ray spectrum both in the hard
and in the soft state in the whole spectral range. We discuss the differences
in the main spectral parameters we find in the hard and the soft state,
respectively, providing evidence that the inner radius of the optically thick
disk slightly recedes in the hard state.Comment: Accepted for publication in A&A, 20 pages, 12 figure
ARCHAEOLOGICAL MATERIALS FROM GABII (CENTRAL ITALY): KNOWLEDGE OF OFFERINGS AND RITUALS AT THE INFANT BURIALS THROUGH AN INTEGRATED APPROACH
The ancient Latin city of Gabii is situated 18 km (11.2 miles) to the east of Rome (Central
Italy) along the modern Via Prenestina. Gabii was a renowned city in Roman times,
particularly during the Republican period and there are various influences in the site that can
be identified in Roman culture itself. Gabii is also one of the most significant and important
archaeological sites in the territory of the Municipality of Rome and due to its
characteristics, it represents today an extraordinary research context. From the excavations
carried out in the past it is possible to see how, under the soil, the main structures and
buildings of the ancient city are still largely preserved. Among the various testimonies of the
past, the tombs, and the micro and macro remains that these contain, represent an
opportunity to investigate such practices in the context of Early Iron Age and Orientalizing
Latium. In particular, the finds from the Area D baby burials of Gabii enriched the existing
dataset so far significantly, allowing us to explore funerary ritual behavior in a more
systematic way.
This work reports the results of the detailed examination of four tombs (Tombs 30, 50, 51
and 52) of archaeological site. The field strategy for the excavation of the tombs was geared
from the start towards both the systematic retrieval of archaeobotanical and
zooarchaeological remains and the sampling for organic residue analysis. Aiming for total
recovery, the sediments from the tomb fills were sifted in their entirety as their stratigraphic
excavation progressed, and samples were taken for flotation. This careful screening allowed
for the detection of concentrations of organic material that represent plant and/or animal
depositions. The excavation and removal of the grave goods was carried out following strict
protocols for residue sampling, minimizing the risk of organic contamination. Samples were
analysed by High Temperature Gas Chromatography/Mass Spectrometry (HTGC/MS) and
Gas chromatography/Combustion/Isotope ratio mass spectrometry (GC-C-IRMS). For each
burial, a subset of vessels including both closed and open shapes was selected, such as cups,
open bowl without foot, amphoretta, amphora with dots, Kantharos, plate on a foot, olla,
and olpe in bucchero.
The results demonstrate the still largely unexploited potential of this sort of integrated
studies, encouraging us to expand the application of chemical methods to contexts from
other well–controlled excavations
Long Process Incus necrosis in Revision Stapedotomy: Retrospective Clinical Study
Objectives: We describe our experience with long process incus (LPI) necrosis in revision stapedotomy and discuss the different management methods proposed in the literature to identify surgical techniques that can lead to satisfactory results over time. Methods: Twenty-two stapedotomy revisions, in 21 patients with the necrosis of the long process of the incus, are performed from 1997 to 2017. In cases of erosion or minimal necrosis of LPI, a new prosthesis of the same type or an angled prosthesis was applied higher on the residual incus stump. In cases of partial necrosis of LPI, a Donaldson type ventilation tube reshaped and placed on the residual incus stump to stabilize prosthesis, or glass ionomer bone cement was used. In cases of subtotal necrosis of LPI, a cup piston prosthesis in polycel was applied on incus residual stump. Pre- and postoperative (≥1 year) pure tone audiometry was performed for all cases. Air conduction threshold, bone conduction (BC) threshold, and air-bone gap (ABG) were documented according to the American Academy of Otolaryngology Head and Neck Surgery Committee of Hearing and Equilibrium guidelines. Results: At 1-year follow-up, postoperative ABG was reduced to ≤10 dB in 13 (59%) cases and ≤20 dB in 19 (86.4%) cases. The mean postoperative ABG significantly decreased in each group. There was no significant change in postoperative BC thresholds, and there were no cases with postoperative SNHL. Conclusion: Excellent functional results can also be achieved in cases of long incus process necrosis. The choice of technique should be considered according to the degree of necrosis. Piston replacement with the same type or angled type prosthesis, in cases of erosion or minimal LPI necrosis, and modified Donaldson type ventilation tube, in cases of partial LPI necrosis, provided excellent hearing results
Data-Driven Methodology for Knowledge Graph Generation Within the Tourism Domain
The tourism and hospitality sectors have become increasingly important in the last few years and the companies operating in this field are constantly challenged with providing new innovative services. At the same time, (big-) data has become the 'new oil' of this century and Knowledge Graphs are emerging as the most natural way to collect, refine, and structure this heterogeneous information. In this paper, we present a methodology for semi-automatic generating a Tourism Knowledge Graph (TKG), which can be used for supporting a variety of intelligent services in this space, and a new ontology for modelling this domain, the Tourism Analytics Ontology (TAO). Our approach processes and integrates data from Booking.com, Airbnb, DBpedia, and GeoNames. Due to its modular structure, it can be easily extended to include new data sources or to apply new enrichment and refinement functions. We report a comprehensive evaluation of the functional, logical, and structural dimensions of TKG and TAO
Evaluating the semantic web: a task-based approach
The increased availability of online knowledge has led to the design of several algorithms that solve a variety of tasks by harvesting the Semantic Web, i.e. by dynamically selecting and exploring a multitude of online ontologies. Our hypothesis is that the performance of such novel algorithms implicity provides an insight into the quality of the used ontologies and thus opens the way to a task-based evaluation of the Semantic Web. We have investigated this hypothesis by studying the lessons learnt about online ontologies when used to solve three tasks: ontology matching, folksonomy enrichment, and word sense disambiguation. Our analysis leads to a suit of conclusions about the status of the Semantic Web, which highlight a number of strengths and weaknesses of the semantic information available online and complement the findings of other analysis of the Semantic Web landscape
Magpie: towards a semantic web browser
Web browsing involves two tasks: finding the right web page and then making sense of its content. So far, research has focused on supporting the task of finding web resources through ‘standard’ information retrieval mechanisms, or semantics-enhanced search. Much less attention has been paid to the second problem. In this paper we describe Magpie, a tool which supports the
interpretation of web pages. Magpie offers complementary knowledge sources, which a reader can call upon to quickly gain access to any background knowledge relevant to a web resource. Magpie automatically associates an ontologybased
semantic layer to web resources, allowing relevant services to be invoked within a standard web browser. Hence, Magpie may be seen as a step towards a semantic web browser. The functionality of Magpie is illustrated using examples of how it has been integrated with our lab’s web resources
Cellulose production is coupled to sensing of the pyrimidine biosynthetic pathway via c-di-GMP production by the DgcQ protein of Escherichia coli
Production of cellulose, a stress response-mediated process in enterobacteria, is modulated in Escherichia coli by the activity of the two pyrimidine nucleotide biosynthetic pathways, namely, the de novo biosynthetic pathway and the salvage pathway, which relies on the environmental availability of pyrimidine nitrogenous bases. We had previously reported that prevalence of the salvage over the de novo pathway triggers cellulose production via synthesis of the second messenger c-di-GMP by the DgcQ (YedQ) diguanylate cyclase. In this work, we show that DgcQ enzymatic activity is enhanced by UTP, whilst being inhibited by N-carbamoyl-aspartate, an intermediate of the de novo pathway. Thus, direct allosteric control by these ligands allows full DgcQ activity exclusively in cells actively synthesizing pyrimidine nucleotides via the salvage pathway. Inhibition of DgcQ activity by N-carbamoyl-aspartate appears to be favoured by protein-protein interaction between DgcQ and PyrB, a subunit of aspartate transcarbamylase, which synthesizes N-carbamoyl-aspartate. Our results suggest that availability of pyrimidine bases might be sensed, somehow paradoxically, as an environmental stress by E. coli. We hypothesize that this link might have evolved since stress events, leading to extensive DNA/RNA degradation or lysis of neighbouring cells, can result in increased pyrimidine concentrations and activation of the salvage pathway
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