956 resultados para locally integrable structures
Resumo:
Bisphosphonates are known for their strong inhibitory effect on bone resorption. Their influence on bone formation however is less clear. In this study we investigated the spatio-temporal effect of locally delivered Zoledronate on peri-implant bone formation and resorption in an ovariectomized rat femoral model. A cross-linked hyaluronic acid hydrogel was loaded with the drug and applied bilaterally in predrilled holes before inserting polymer screws. Static and dynamic bone parameters were analyzed based on in vivo microCT scans performed first weekly and then biweekly. The results showed that the locally released Zoledronate boosted bone formation rate up to 100% during the first 17 days after implantation and reduced the bone resorption rate up to 1000% later on. This shift in bone remodeling resulted in an increase in bone volume fraction (BV/TV) by 300% close to the screw and 100% further away. The double effect on bone formation and resorption indicates a great potential of Zoledronate-loaded hydrogel for enhancement of peri-implant bone volume which is directly linked to improved implant fixation.
Resumo:
The transpressional boundary between the Australian and Pacific plates in the central South Island of New Zealand comprises the Alpine Fault and a broad region of distributed strain concentrated in the Southern Alps but encompassing regions further to the east, including the northwest Canterbury Plains. Low to moderate levels of seismicity (e. g., 2 > M 5 events since 1974 and 2 > M 4.0 in 2009) and Holocene sediments offset or disrupted along rare exposed active fault segments are evidence for ongoing tectonism in the northwest plains, the surface topography of which is remarkably flat and even. Because the geology underlying the late Quaternary alluvial fan deposits that carpet most of the plains is not established, the detailed tectonic evolution of this region and the potential for larger earthquakes is only poorly understood. To address these issues, we have processed and interpreted high-resolution (2.5 m subsurface sampling interval) seismic data acquired along lines strategically located relative to extensive rock exposures to the north, west, and southwest and rare exposures to the east. Geological information provided by these rock exposures offer important constraints on the interpretation of the seismic data. The processed seismic reflection sections image a variably thick layer of generally undisturbed younger (i.e., < 24 ka) Quaternary alluvial sediments unconformably overlying an older (> 59 ka) Quaternary sedimentary sequence that shows evidence of moderate faulting and folding during and subsequent to deposition. These Quaternary units are in unconformable contact with Late Cretaceous-Tertiary interbedded sedimentary and volcanic rocks that are highly faulted, folded, and tilted. The lowest imaged unit is largely reflection-free Permian Triassic basement rocks. Quaternary-age deformation has affected all the rocks underlying the younger alluvial sediments, and there is evidence for ongoing deformation. Eight primary and numerous secondary faults as well as a major anticlinal fold are revealed on the seismic sections. Folded sedimentary and volcanic units are observed in the hanging walls and footwalls of most faults. Five of the primary faults represent plausible extensions of mapped faults, three of which are active. The major anticlinal fold is the probable continuation of known active structure. A magnitude 7.1 earthquake occurred on 4 September 2010 near the southeastern edge of our study area. This predominantly right-lateral strike-slip event and numerous aftershocks (ten with magnitudes >= 5 within one week of the main event) highlight the primary message of our paper: that the generally flat and topographically featureless Canterbury Plains is underlain by a network of active faults that have the potential to generate significant earthquakes.
Resumo:
OBJECTIVE: To present a series of localized fibrous tumours of the pleura (LFTP), to define the clinical and histopathological diagnostic criteria of this tumour, and to determine the optimal treatment and follow-up. METHODS: Review of the charts of the patients with the diagnosis of LFTP (formerly called benign fibrous mesothelioma), as well as of all the histological sections, including immunohistochemical stains. Review of the literature with special emphasis on the clinical and histological criteria of malignancy. RESULTS: During the last 30 years, we found 15 patients with a complete clinical chart and histological material, particularly paraffin blocks of the tumour. The mean age was 57 years (range 27-79). Eight patients were asymptomatic, and the remaining seven presented with non-specific symptoms. All but one had complete resection of the tumour, including partial lung resection in two and partial chest wall resection in three. The diagnosis was confirmed by histological review in 15 cases. Immunohistochemical stainings showed positivity for vimentin in all cases, for CD 34 in 80%, but were consistently negative for cytokeratins. Nine tumours were histologically classified as malignant. Among them, five recurred, two of which were responsible for death. One benign tumour recurred after 1 year, and was treated successfully by repeat resection and radiotherapy. Overall, 13 patients (86%) were alive with no evidence of disease between 10 months and 27 years after the first resection. CONCLUSIONS: LFTP is a rare tumour which has a benign clinical course in over 80% of the cases, and is asymptomatic in half the patients. The diagnosis is difficult to establish before operation. Treatment consists of complete resection including adjacent structures if necessary. The clinical behaviour of LFTP cannot be predicted on the basis of histological aspects only. If histologically malignant tumours are more prone to recurrence and poor outcome, broad-based and locally invasive tumours bear a higher risk of recurrence. Long term follow-up is therefore mandatory in all cases in order to perform early re-resection when recurrence occurs.
Resumo:
Aquest treball és una revisió d'alguns sistemes de Traducció Automàtica que segueixen l'estratègia de Transfer i fan servir estructures de trets com a eina de representació. El treball s'integra dins el projecte MLAP-9315, projecte que investiga la reutilització de les especificacions lingüístiques del projecte EUROTRA per estàndards industrials.
Resumo:
The overarching goal of the proposed research was to evaluate the hydraulic performance of twenty two (22) fish-passage structures located in close proximity to bridges in western Iowa and within the HCA (Hungry Canyon Alliance) territory. Such structures include riprap weirs, fish ladders and grouted ripraps. The hydraulic performance of the aforementioned structures was evaluated via detailed field tests for a range of flow conditions relevant to fish migration through bridge waterways in different streams in western Iowa.
Resumo:
The shrews of the Sorex araneus group, characterized by the sexual chromosome complex XY1, Y2 have been intensively studied by morphological, karyotypical, and biochemical analyses. Nevertheless, the phylogenetic relationships among the species belonging to the araneus complex are still under debate, as different approaches gave often contradictory results. In this paper, partial nucleotide sequences of the mitochondrial DNA cytochrome b gene (1011 bp) were determined for 6 species of the araneus group from Eurasia and North America. We also included in the data set the sequences of Sorex samniticus, whose relationships with the araneus group remain controversial. Three other species representing two major karyological groups were also examined. Both parsimony and distance trees strongly support the monophyly of the araneus group. Sorex sumniticus is significantly more closely related to the araneus complex than to the other species included in the analysis. Based on the branching pattern within the araneus group, an attempt has been made to reconstruct the colonization history of the Holarctic region.
Resumo:
Data mining can be defined as the extraction of previously unknown and potentially useful information from large datasets. The main principle is to devise computer programs that run through databases and automatically seek deterministic patterns. It is applied in different fields of application, e.g., remote sensing, biometry, speech recognition, but has seldom been applied to forensic case data. The intrinsic difficulty related to the use of such data lies in its heterogeneity, which comes from the many different sources of information. The aim of this study is to highlight potential uses of pattern recognition that would provide relevant results from a criminal intelligence point of view. The role of data mining within a global crime analysis methodology is to detect all types of structures in a dataset. Once filtered and interpreted, those structures can point to previously unseen criminal activities. The interpretation of patterns for intelligence purposes is the final stage of the process. It allows the researcher to validate the whole methodology and to refine each step if necessary. An application to cutting agents found in illicit drug seizures was performed. A combinatorial approach was done, using the presence and the absence of products. Methods coming from the graph theory field were used to extract patterns in data constituted by links between products and place and date of seizure. A data mining process completed using graphing techniques is called ``graph mining''. Patterns were detected that had to be interpreted and compared with preliminary knowledge to establish their relevancy. The illicit drug profiling process is actually an intelligence process that uses preliminary illicit drug classes to classify new samples. Methods proposed in this study could be used \textit{a priori} to compare structures from preliminary and post-detection patterns. This new knowledge of a repeated structure may provide valuable complementary information to profiling and become a source of intelligence.
Resumo:
Using data for all the fixtures for the seasons from 1972-73 to 2002-03, we estimate a dynamic model of demand for football pools in Spain paying attention to whether their main economic explanatory variable is the effective price of a ticket or the jackpot. Additionally, we evaluate the importance of the composition of the list of games in terms of whether First Division matches are included or not. Results show that the jackpot model is preferred to the effective price model, having important implications in terms of how the structure of the game should be changed in order to increase demand.
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Structural equation models are widely used in economic, socialand behavioral studies to analyze linear interrelationships amongvariables, some of which may be unobservable or subject to measurementerror. Alternative estimation methods that exploit different distributionalassumptions are now available. The present paper deals with issues ofasymptotic statistical inferences, such as the evaluation of standarderrors of estimates and chi--square goodness--of--fit statistics,in the general context of mean and covariance structures. The emphasisis on drawing correct statistical inferences regardless of thedistribution of the data and the method of estimation employed. A(distribution--free) consistent estimate of $\Gamma$, the matrix ofasymptotic variances of the vector of sample second--order moments,will be used to compute robust standard errors and a robust chi--squaregoodness--of--fit squares. Simple modifications of the usual estimateof $\Gamma$ will also permit correct inferences in the case of multi--stage complex samples. We will also discuss the conditions under which,regardless of the distribution of the data, one can rely on the usual(non--robust) inferential statistics. Finally, a multivariate regressionmodel with errors--in--variables will be used to illustrate, by meansof simulated data, various theoretical aspects of the paper.
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In moment structure analysis with nonnormal data, asymptotic valid inferences require the computation of a consistent (under general distributional assumptions) estimate of the matrix $\Gamma$ of asymptotic variances of sample second--order moments. Such a consistent estimate involves the fourth--order sample moments of the data. In practice, the use of fourth--order moments leads to computational burden and lack of robustness against small samples. In this paper we show that, under certain assumptions, correct asymptotic inferences can be attained when $\Gamma$ is replaced by a matrix $\Omega$ that involves only the second--order moments of the data. The present paper extends to the context of multi--sample analysis of second--order moment structures, results derived in the context of (simple--sample) covariance structure analysis (Satorra and Bentler, 1990). The results apply to a variety of estimation methods and general type of statistics. An example involving a test of equality of means under covariance restrictions illustrates theoretical aspects of the paper.
Efficiency and equilibrium with locally increasing aggregate returns due to demand complementarities
Resumo:
We extend to score, Wald and difference test statistics the scaled and adjusted corrections to goodness-of-fit test statistics developed in Satorra and Bentler (1988a,b). The theory is framed in the general context of multisample analysis of moment structures, under general conditions on the distribution of observable variables. Computational issues, as well as the relation of the scaled and corrected statistics to the asymptotic robust ones, is discussed. A Monte Carlo study illustrates thecomparative performance in finite samples of corrected score test statistics.