198,627 research outputs found
Do Kawasaki disease patients without coronary artery abnormalities need a long-term follow-up? A myocardial single-photon emission computed tomography pilot study
No full textJ Paediatr Child Health. 2009 Jul-Aug;45(7-8):419-24. Epub 2009 Jul 20.
Do Kawasaki disease patients without coronary artery abnormalities need a long-term follow-up? A myocardial single-photon emission computed tomography pilot study.
Zanon G, Zucchetta P, Varnier M, Vittadello F, Milanesi O, Zulian F.
Source
Rheumatology Unit, Department of Paediatrics, University of Padua, 35128 Padua, Italy.
Abstract
OBJECTIVE:
To determine the frequency and risk factors for long-term myocardial perfusion scintigraphy abnormalities in patients with Kawasaki disease (KD).
METHODS:
A cohort of patients with KD at least 3 years after disease onset and with persistent coronary artery aneurysms (CAA) (group 1) or without CAA (group 2) underwent stress-rest myocardial single-photon emission computed tomography (SPECT). Clinical and laboratory parameters at disease onset were considered to assess their predictive value for the development of myocardial perfusion abnormalities.
RESULTS:
Forty patients, 20 in group 1 and 20 in group 2, entered the study. The two groups turned out to be comparable for demographic, clinical and laboratory characteristics. Five patients (12.5%), two in group 1 and three in group 2, had abnormal myocardial perfusion assessed by SPECT. Neither the presence of CAA nor the overall cardiac involvement at the disease onset significantly increased the risk for these abnormalities.
CONCLUSION:
Cardiac SPECT abnormalities are not unusual in KD and can be found in patients with or without CAA. If confirmed in a larger cohort of patients, these preliminary data indicate that careful long-term cardiac follow-up should be considered, regardless of the presence of CAA.
PMID:
19712178
[PubMed - indexed for MEDLINE
Testing the robustness of primary production models in shallow coastal areas: a case study
No full textIn this paper we investigate the robustness of a dynamic model, which describes the dynamic of the seagrass Zostera marina, with respect to the inter-annual variability of the two main forcing functions of primary production models in eutrophicated environments. The model was previously applied to simulate the seasonal evolution of this species in the Lagoon of Venice during a specific year and calibrated against time series of field data. In the this paper, we present and discuss the results which were obtained by forcing the model using time series of site-specific daily values concerning the solar radiation intensity and water temperature. The latter was estimated by means of a regression model, whose input variable was a site-specific time series of the air temperature. The regression model was calibrated using a year-long time series of hourly observations. The Z marina model was first partially recalibrated against the same data set that was used in the original paper. Subsequently, the model was forced using a 7-year-long time series of the driving functions, in order to check the reliability of its long-term predictions. Even though the calibration gave satisfactory results, the multi-annual trends of the output variables were found to be in contrast with the observed evolution of the seagrass biomasses. Since detailed information about the air temperature and solar radiation are often available, these findings suggest that the testing of the ecological consistency of the evolution of primary production models in the long term would provide additional confidence in their results, particularly in those cases in which the scarcity of field data does not allow one to perform a formal corroboration/validation of these models
Muon trigger with fast Neural Networks on FPGA, a demonstrator
No full textThe online reconstruction of muon tracks in High Energy Physics experiments is a highly demanding task, typically performed on reconfigurable digital circuits, such as FPGAs. Complex analytical algorithms are executed in a quasi-real-time environment to identify, select, and reconstruct local tracks in often noise-rich environments. A novel approach to the generation of local triggers based on a hybrid combination of Artificial Neural Networks and analytical methods is proposed, targeting the muon reconstruction for drift tube detectors. The proposed algorithm exploits Neural Networks to solve otherwise computationally expensive analytical tasks for the unique identification of coherent signals and the removal of geometrical ambiguities. The proposed approach is deployed on state-of-the-art FPGA and its performances are evaluated on simulation and on data collected from cosmic rays
Local habitat and seascape structure influence seagrass fish assemblages in the Venice lagoon: the value of conservation at multiple spatial scales.
No full textSeagrass meadows are a critical component of estuarine and coastal seascapes, and their structure influences fish assemblages at multiple spatial scales. The patch mosaic mode l, which defines the seascape as a collection of interacting habitat types, is increasingly dopted to prioritise protected areas and design ecological restoration schemes, hence helping to preserve seagrass meadows and the associated fish assemblages. Despite that, the re are few studies investigating the relative contribution of environmental characteristics measured at different spatial scales in determining the distribution of seagrass fish. This study collects fish and environmental observations taken at both site and seascape scales in seagrass meadows in the Venice lagoon (Adriatic Sea, Italy). By means of generalised linear models, it aims to disentangle the relative influence of local water qua
lity and habitat characteristics from that of habitat mosaic properties, investigating the response of whole fish assemblage descriptors, feeding guilds and dominant species. While confirming the primary importance of local habitat quality
, the study highlights that also seagrass habitat structure at the seascape scale is relevant for seagrass fish assemblages, influencing total biomass, biomass of macrobenthivorous and hyperbenthivorous/piscivorous species and seagrass specialists
such as syngnathids. Conservation of seagrass fish assemblages can therefore be promoted in Mediterranean coastal lagoons by preserving or restoring some features of the habitat mosaic, namely the extension of seagrass patches and their shape complexity, in addition to local water quality and seagrass cover
Uncertainty in developing fish based multi-metric indices
No full textThe process of development of a multi-metric index (MMI) implies a series of decisions to complete the procedure and obtain the formulation of an indicator. We performed an uncertainty and sensitivity analysis to explore the effects of alternative decisions in this process, using the case of fish fauna-based assessment of the ecological status in transitional waters and the Venice lagoon as an example. We formulated the alternative strategies in MMI implementation as levels of three factors affecting this procedure: 1) metrics pre-selection; 2) metrics numerical pre-treatment; 3) and metrics combination rules. The outcome of the uncertainty analysis highlighted that all the decisions impacted the process, potentially leading to indicators with different characteristics, confirming that the process of developing MMIs – even following an empirical data-driven approach – is not a completely objective procedure. However, not all the choices have the same weight in influencing the final index, nor do they affect the same characteristics of the index. The initial choice of candidate metrics influences the number of metrics included in the final index, the correlation of the MMI with anthropogenic pressures and the ecological status classification (i.e. the output of the index itself). However, the most influential decision is the one related to the criterion adopted to select the metrics (i.e. to reduce the number of metrics from the original candidate set) included in the final index. This choice is the one that most likely affects the structure of the index and the ecological status classification, even if the family of indices developed in this work exhibited a certain level of robustness regarding this characteristic
An ecological imbalance induced by a non-native species: the Manila clam in the Venice Lagoon
No full textAmong the 19 non-native species of marine invertebrates which have invaded the Venice Lagoon and have\ud
established populations, Ruditapes philippinarum, deliberately introduced in 1983, is surely the most successful\ud
species. According to the hypothesis that alien species invasion could be favoured by an altered\ud
ecological, chemical or physical state of the system induced by anthropogenic disturbance, R. philippinarum\ud
turned out to be ‘the right species at the right moment’. By comparing historical data (1968, 1985, 1990)\ud
with 1999 data, changes in macrobenthic community, in particular bivalve molluscs, of the lagoon induced\ud
by R. philippinarum introduction and subsequent clam exploiting activity were assessed. It has been possible\ud
to describe a sharp reduction, both in terms of distribution area and density, of all other filter feeder\ud
bivalves. Moreover, by using the clearance rate of the most abundant bivalve species in 1990 and 1999\ud
(Cerastoderma glaucum and R. philippinarum, respectively), it was possible to estimate that the filtration\ud
capacity, expressed as l h)1 m)2, has more than doubled. This has altered the functioning of the ecosystem,\ud
resulting in a stronger benthic–pelagic coupling. In this context, R. philippinarum attains control of the\ud
system. Considering all this, it is possible to state that the Venice Lagoon ecosystem has entered into a new\ud
state, probably more resistant but less resilient, with implications for future management choices
A horizontally scalable online processing system for trigger-less data acquisition
No full textThe vast majority of high energy physics experiments rely on data acquisition and hardware-based trigger systems performing a number of stringent selections before storing data for offline analysis. The online reconstruction and selection performed at the trigger level are bound to the synchronous nature of the data acquisition system, resulting in a trade-off between the amount of data collected and the complexity of the online reconstruction performed. Exotic physics processes, such as long-lived and slow-moving particles, are rarely targeted by online triggers as they require complex and nonstandard online reconstruction, usually incompatible with the time constraints of most data acquisition systems. The online trigger selection can thus impact as one of the main limiting factors to the experimental reach for exotic signatures. Alternative data acquisition solutions based on the continuous and asynchronous processing of the stream of data from the detectors are therefore foreseeable as a way to extend the experimental physics reach. Trigger-less data readout systems, paired with efficient streaming data processing solutions, can provide a viable alternative. In this document, an end-to-end implementation of a fully trigger-less data acquisition and online data processing system is discussed. An easily scalable and deployable implementation of such an architecture is proposed, based on open-source distributed computing frameworks capable of performing asynchronous online processing of streaming data. The proposed schema can be suitable for deployment as a fully integrated data acquisition system for small-scale experimental apparatus, or to complement the trigger-based data acquisition systems of larger experiments. A muon telescope setup consisting of a set of gaseous detectors is used as the experimental development testbed in this work, and a fully integrated online processing pipeline deployed on cloud computing resources is implemented and described
Trigger-less readout and unbiased data quality monitoring of the CMS drift tubes muon detector
No full textThe CMS experiment 40 MHz data scouting project is aimed at intercepting the data produced at the level of the detectors' front-end without the filters induced by hardware-based triggers. A first implementation is realized by the trigger-less reading and processing of a fraction of the Drift Tube (DT) muon detector, equipped with a preliminary version of the so-called Phase-2 Upgrade on-detector electronics boards. The data are transferred via high-speed optical links to back-end boards independently from the central experiment data acquisition (DAQ), permitting real-time detector status monitoring via receiving all the signals produced at the front-end level, and providing an unbiased estimate of the CMS DT hit-rate under various data-taking conditions
Dr. Duane M. Jackson, Morehouse College, July 2011
No full textThis video is a conversation with Dr. Duane M. Jackson. Dr. Jackson talks about his paper, "Recall and the Serial Position Effect: The Role of Primacy and Recency on Accounting Students' Performance." Jackie Daniel, AUC Woodruff Library, is the interviewer
- …
