93 research outputs found
Maximizing the Use of Computational Resources in Multi-Camera Feedback Control
In vision-based feedback control systems, the time to obtain sensor information is usually non-negligible, and these systems thereby possess fundamentally different timing behavior compared to standard real-time control applications. For many image-based tracking algorithms, however, it is possible to trade-off the computational time versus the accuracy of the produced position/orientation estimates.This paper presents a method for optimizing the use of computational resources in a multi-camera based positioning system. A simplified equation for the covariance of the position estimation error is calculated, which depends on the set of cameras used and the number of edge detection points in each image. An efficient algorithm for selection of a suitable subset of the available cameras is presented, which attempts to minimize the estimation covariance given a desired, pre-specified maximum input-output latency of the feedback control loop.Simulations have been performed that capture the real-time properties of the vision-based tracking algorithm and the effects of the timing on the performance of the control system. The suggested strategy has been compared with heuristic algorithms, and it obtains large improvements in estimation accuracy and performance for objects both in free motion and under closed-loop position control
Psychophysiological anomalies? : Insights into the orienting response in studies with unconventional questioning
Das Projekt beschäftigte sich mit der Frage, ob physiologische Reaktionen von Personen durch Ereignisse auslöst werden können, auch wenn diese Ereignisse aus konventioneller Sicht nicht wahrnehmbar sind, weil sie an einem anderen Ort oder erst in der Zukunft stattfinden. Hinweise darauf wurden wiederholt in Studien mit einer speziellen Rateaufgabe gefunden. In dem Projekt wurde erstmals das Konzept der Orientierungsreaktion für die Untersuchung solcher anomalen Zusammenhänge zwischen Ereignissen und physiologischen Reaktionen herangezogen. In drei Studien wurde untersucht, ob bei der seriellen Präsentation von Objekten eine verstärkte Orientierungsreaktion bei dem Objekt (Zielobjekt) auftritt, das aufgrund eines aus konventioneller Sicht nicht wahrnehmbaren Ereignisses eine spezifische Bedeutsamkeit hat. In Studie 1 kam ein modifizierter Tatwissentest zum Einsatz, in Studie 2 die Rateaufgabe. In Studie 3 wurden beide Methoden kombiniert. Als methodologische Fragestellung wurde der Einfluss von Positionseffekten in Experimenten mit serieller Objektpräsentation untersucht. Die konzeptuelle Fragestellung beschäftigte sich mit neuen Erkenntnissen über die Orientierungsreaktion. Die Ergebnisse zeigten keine statistisch signifikanten Unterschiede zwischen Zielobjekten und irrelevanten Objekten in der elektrodermalen Aktivität, der phasischen und tonischen Herzrate, der Atemaktivität und der Pulsaktivität (p > .1, d .1, d < .15). Evidence was found for a confound of physiological responses with the serial position of objects. As a result, simulated studies showed a biased level of significance if the stimulus positions were unbalanced. Therefore, the probability of a false rejection of the null hypothesis was increased a priori. Taken together, the project provided no evidence for physiological responses that were evoked by events that are conventionally considered as unperceivable. The methodological analysis implies a statistical bias in prior studies that used the guessing task. An increased probability of a false rejection of the null hypothesis is preventable by balancing the positions of the stimuli. The observed effects of serial positioning suggest an integration of the effects of information processing and decision making into the concept of the orienting response
Tree water uptake enhances nitrogen acquisition in a fertilized boreal forest - but not under nitrogen-poor conditions
Understanding how plant water uptake interacts with acquisition of soil nitrogen (N) and other nutrients is fundamental for predicting plant responses to a changing environment, but it is an area where models disagree. We present a novel isotopic labelling approach which reveals spatial patterns of water and N uptake, and their interaction, by trees. The stable isotopes N-15 and H-2 were applied to a small area of the forest floor in stands with high and low soil N availability. Uptake by surrounding trees was measured. The sensitivity of N acquisition to water uptake was quantified by statistical modelling. Trees in the high-N stand acquired twice as much N-15 as in the low-N stand and around half of their N uptake was dependent on water uptake (H-2 enrichment). By contrast, in the low-N stand there was no positive effect of water uptake on N uptake. We conclude that tree N acquisition was only marginally dependent on water flux toward the root surface under low-N conditions whereas under high-N conditions, the water-associated N uptake was substantial. The results suggest a fundamental shift in N acquisition strategy under high-N conditions
Afternoon exercise is more efficacious than morning exercise at improving blood glucose levels in individuals with type 2 diabetes : a randomised crossover trial
Data availability The data analysed during the current study are available from the corresponding author on reasonable request. Funding The authors are supported by grants from Novo Nordisk Foundation (NNF14OC0011493 and NNF14OC0009941), Swedish Diabetes Foundation (DIA2015-052), Wenner-Gren Foundation, Swedish Research Council (2015-00165), Strategic Research Program in Diabetes at Karolinska Institutet (2009-1068), Stockholm County Council (SLL20150517 and SLL20170159) and Swedish Heart Lung Foundation (20150423).Peer reviewedPublisher PD
Comparison of cisplatin sensitivity and the 18F fluoro-2-deoxy 2 glucose uptake with proliferation parameters and gene expression in squamous cell carcinoma cell lines of the head and neck
<p>Abstract</p> <p>Background</p> <p>The survival of patients with locally advanced head and neck cancer is still poor, with 5-year survival rates of 24–35%. The identification of prognostic and predictive markers at the molecular and cellular level could make it possible to find new therapeutic targets and provide "taylor made" treatments. Established cell lines of human squamous cell carcinoma (HNSCC) are valuable models for identifying such markers.</p> <p>The aim of this study was to establish and characterize a series of cell lines and to compare the cisplatin sensitivity and 18F fluoro-2 deoxy 2 glucose (18F-FDG) uptake of these cell lines with other cellular characteristics, such as proliferation parameters and TP53 and CCND1 status.</p> <p>Methods</p> <p>Explant cultures of fresh tumour tissue were cultivated, and six new permanent cell lines were established from 18 HNSCC cases. Successfully grown cell lines were analysed regarding clinical parameters, histological grade, karyotype, DNA ploidy, and index and S-phase fraction (Spf). The cell lines were further characterized with regard to their uptake of 18F-FDG, their sensitivity to cisplatin, as measured by a viability test (crystal violet), and their TP53 and CCND1 status, by fluorescence in situ hybridization (FISH), polymerase chain reaction single-strand conformation polymorphism (PCR-SSCP) with DNA sequencing and, for cyclin D1, by immunohistochemistry.</p> <p>Results</p> <p>Patients with tumours that could be cultured in vitro had shorter disease-free periods and overall survival time than those whose tumours did not grow in vitro, when analysed with the Kaplan-Meier method and the log-rank test. Their tumours also showed more complex karyotypes than tumours from which cell lines could not be established. No correlation was found between TP53 or CCND1 status and 18F-FDG uptake or cisplatin sensitivity. However, there was an inverse correlation between tumour cell doubling time and 18F-FDG uptake.</p> <p>Conclusion</p> <p>In vitro growth of HNSCC cells seem to be an independent prognostic factor, with cell lines being more readily established from aggressive tumours, a phenomenon more dependent on the molecular genetic characteristics of the tumour cells than on tumour location or TNM status.</p
Electrical Pulse Stimulation of Cultured Human Skeletal Muscle Cells as an In Vitro Model of Exercise
Background and Aims
Physical exercise leads to substantial adaptive responses in skeletal muscles and plays a central role in a healthy life style. Since exercise induces major systemic responses, underlying cellular mechanisms are difficult to study in vivo. It was therefore desirable to develop an in vitro model that would resemble training in cultured human myotubes.
Methods
Electrical pulse stimulation (EPS) was applied to adherent human myotubes. Cellular contents of ATP, phosphocreatine (PCr) and lactate were determined. Glucose and oleic acid metabolism were studied using radio-labeled substrates, and gene expression was analyzed using real-time RT-PCR. Mitochondrial content and function were measured by live imaging and determination of citrate synthase activity, respectively. Protein expression was assessed by electrophoresis and immunoblotting.
Results
High-frequency, acute EPS increased deoxyglucose uptake and lactate production, while cell contents of both ATP and PCr decreased. Chronic, low-frequency EPS increased oxidative capacity of cultured myotubes by increasing glucose metabolism (uptake and oxidation) and complete fatty acid oxidation. mRNA expression level of pyruvate dehydrogenase complex 4 (PDK4) was significantly increased in EPS-treated cells, while mRNA expressions of interleukin 6 (IL-6), cytochrome C and carnitin palmitoyl transferase b (CPT1b) also tended to increase. Intensity of MitoTracker®Red FM was doubled after 48 h of chronic, low-frequency EPS. Protein expression of a slow fiber type marker (MHCI) was increased in EPS-treated cells.
Conclusions
Our results imply that in vitro EPS (acute, high-frequent as well as chronic, low-frequent) of human myotubes may be used to study effects of exercise.This work was funded by the University of Oslo, Oslo University College, the Norwegian Diabetes Foundation, the Freia Chocolade Fabriks Medical Foundation and the Anders Jahre’s Foundation. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript
Multiplex Real-Time PCR Assay Using TaqMan Probes for the Identification of Trypanosoma cruzi DTUs in Biological and Clinical Samples
Background:
Trypanosoma cruzi has been classified into six Discrete Typing Units (DTUs), designated as TcI–TcVI. In order to effectively use this standardized nomenclature, a reproducible genotyping strategy is imperative. Several typing schemes have been developed with variable levels of complexity, selectivity and analytical sensitivity. Most of them can be only applied to cultured stocks. In this context, we aimed to develop a multiplex Real-Time PCR method to identify the six T. cruzi DTUs using TaqMan probes (MTq-PCR).Methods/Principal Findings:
The MTq-PCR has been evaluated in 39 cultured stocks and 307 biological samples from vectors, reservoirs and patients from different geographical regions and transmission cycles in comparison with a multi-locus conventional PCR algorithm. The MTq-PCR was inclusive for laboratory stocks and natural isolates and sensitive for direct typing of different biological samples from vectors, reservoirs and patients with acute, congenital infection or Chagas reactivation. The first round SL-IR MTq-PCR detected 1 fg DNA/reaction tube of TcI, TcII and TcIII and 1 pg DNA/reaction tube of TcIV, TcV and TcVI reference strains. The MTq-PCR was able to characterize DTUs in 83% of triatomine and 96% of reservoir samples that had been typed by conventional PCR methods. Regarding clinical samples, 100% of those derived from acute infected patients, 62.5% from congenitally infected children and 50% from patients with clinical reactivation could be genotyped. Sensitivity for direct typing of blood samples from chronic Chagas disease patients (32.8% from asymptomatic and 22.2% from symptomatic patients) and mixed infections was lower than that of the conventional PCR algorithm.Conclusions/Significance:
Typing is resolved after a single or a second round of Real-Time PCR, depending on the DTU. This format reduces carryover contamination and is amenable to quantification, automation and kit production.This work received financial support from the Ministry of Science and Technology of Argentina [PICT 2011-0207 to AGS] and the National Scientific and Technical Research Council in Argentina (CONICET) [PIP 112 2011-010-0974 to AGS]. Work related to evaluation of biological samples was partially sponsored by the Pan-American Health Organization (PAHO) [Small Grants Program PAHO-TDR]; the Drugs and Neglected Diseases Initiative (DNDi, Geneva, Switzerland), Wellcome Trust (London, United Kingdom), SANOFI-AVENTIS (Buenos Aires, Argentina) and the National Council for Science and Technology in Mexico (CONACYT) [FONSEC 161405 to JMR]
Processing unit resources in a distributed computing systems
The described program is designed for collecting, storing and processing data of distributed file system
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