742 research outputs found
On Second-Order Monadic Monoidal and Groupoidal Quantifiers
We study logics defined in terms of second-order monadic monoidal and
groupoidal quantifiers. These are generalized quantifiers defined by monoid and
groupoid word-problems, equivalently, by regular and context-free languages. We
give a computational classification of the expressive power of these logics
over strings with varying built-in predicates. In particular, we show that
ATIME(n) can be logically characterized in terms of second-order monadic
monoidal quantifiers
Preliminary results of a phase II study of brentuximab vedotin using a response adapted design for the first line treatment of patients with Hodgkin lymphoma unsuitable for chemotherapy due to age, frailty or co-morbidity (BREVITY)
Results of a phase II study of brentuximab vedotin in the first line treatment of Hodgkin lymphoma patients considered unsuitable for standard chemotherapy (BREVITY)
Investigation of initiation of gigantic jets connecting thunderclouds to the ionosphere
The initiation of giant electrical discharges called as "gigantic jets"
connecting thunderclouds to the ionosphere is investigated by numerical
simulation method in this paper. Using similarity relations, the triggering
conditions of streamer formation in laboratory situations are extended to form
a criterion of initiation of gigantic jets. The energy source causing a
gigantic jet is considered due to the quasi-electrostatic field generated by
thunderclouds. The electron dynamics from ionization threshold to streamer
initiation are simulated by the Monte Carlo technique. It is found that
gigantic jets are initiated at a height of ~18-24 km. This is in agreement with
the observations. The method presented in this paper could be also applied to
the analysis of the initiation of other discharges such as blue jets and red
sprites.Comment: 12th International Congress on Plasma Physics, 25-29 October 2004,
Nice (France
Simultaneous 13N-Ammonia and gadolinium first-pass myocardial perfusion with quantitative hybrid PET-MR imaging: a phantom and clinical feasibility study
Background
Positron emission tomography (PET) is the non-invasive reference standard for myocardial blood flow (MBF) quantification. Hybrid PET-MR allows simultaneous PET and cardiac magnetic resonance (CMR) acquisition under identical experimental and physiological conditions. This study aimed to determine feasibility of simultaneous 13N-Ammonia PET and dynamic contrast-enhanced CMR MBF quantification in phantoms and healthy volunteers.
Methods
Images were acquired using a 3T hybrid PET-MR scanner. Phantom study: MBF was simulated at different physiological perfusion rates and a protocol for simultaneous PET-MR perfusion imaging was developed. Volunteer study: five healthy volunteers underwent adenosine stress. 13N-Ammonia and gadolinium were administered simultaneously. PET list mode data was reconstructed using ordered subset expectation maximisation. CMR MBF was quantified using Fermi function-constrained deconvolution of arterial input function and myocardial signal. PET MBF was obtained using a one-tissue compartment model and image-derived input function.
Results
Phantom study: PET and CMR MBF measurements demonstrated high repeatability with intraclass coefficients 0.98 and 0.99, respectively. There was high correlation between PET and CMR MBF (r = 0.98, p < 0.001) and good agreement (bias − 0.85 mL/g/min; 95% limits of agreement 0.29 to − 1.98). Volunteer study: Mean global stress MBF for CMR and PET were 2.58 ± 0.11 and 2.60 ± 0.47 mL/g/min respectively. On a per territory basis, there was moderate correlation (r = 0.63, p = 0.03) and agreement (bias − 0.34 mL/g/min; 95% limits of agreement 0.49 to − 1.18).
Conclusion
Simultaneous MBF quantification using hybrid PET-MR imaging is feasible with high test repeatability and good to moderate agreement between PET and CMR. Future studies in coronary artery disease patients may allow cross-validation of techniques
Prosocial Spending and Well-Being: Cross-Cultural Evidence for a Psychological Universal
This research provides the first support for a possible psychological universal: human beings around the world derive emotional benefits from using their financial resources to help others (prosocial spending). Analyzing survey data from 136 countries, we show that prosocial spending is consistently associated with greater happiness. To test for causality, we conduct experiments within two very different countries (Canada and Uganda) and show that spending money on others has a consistent, causal impact on happiness. In contrast to traditional economic thought—which places self-interest as the guiding principle of human motivation—our findings suggest that the reward experienced from helping others may be deeply ingrained in human nature, emerging in diverse cultural and economic contexts.
Maintenance care for treated periodontitis patients
This paper is a review of current literature combined with clinical observations. Well-controlled maintenance care is a key consideration in the long-term prognosis of treated periodontitis patients. Periodic professional tooth cleaning every 3 to 4 months often is recommended. Furthermore, recent studies indicate a potential need for selected retreatment in problem areas, since minute residual accretions may be left behind during active therapy - even with “open” surgery. While efficient plaque control is essential for optimal results during the healing phase of periodontal therapy, periodic prophylaxis may prevent loss of clinical attachment over long periods of time even for patients with less than perfect oral hygiene.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/72615/1/j.1600-051X.1987.tb02247.x.pd
Fibre-optic measurement of strain and shape on a helicopter rotor blade during a ground run: 1. Measurement of strain
Insight into aquaculture's potential of marine annelid worms and ecological concerns: a review
Polychaetes are marine annelid worms that can contribute to aquaculture diversification. Its culture has been viable, and commercially attempted, but intensive
production has progressed only in few countries around the world. In the countries with no production, marine polychaetes are imported or harvested. A strong
and sustained research investment provided to a better understanding of the
nutritional requirements and reproduction of some species. Recent studies
showed new technical improvements, which can lead to an important progress in
productivity and give a new impetus to the polychaete production. Some marine
worm species were identified as good candidates for integrated multitrophic
aquaculture. The development of cost-effective aquaculture techniques for marine
annelid worms is essential to ensure a balance between commercial interests and
the preservation of ecosystems. The influence of polychaete aquaculture on the
environment and vice versa raise important concerns related to ecological security
and sustainability of this activity. This review focus on the main technical
improvements and advances that have been made in areas as diverse as: aquaculture potential of polychaetes, reared species, main species used worldwide, and
highlights biological and ecological concerns, important challenges and recommendations.This study was supported by the
FCT (Portuguese National Board of Scientific Research),
through the MARE (Marine and Environmental Sciences
Centre) (UID/MAR/04292/2013) strategic programme and
through strategic project PEst-OE/MAR/UI0199/2014,
granted to MARE. This study has also the financial support
of PROMAR Program through the project 31-03-05-FEP42: LIVE BAIT – Annelid polychaetes as live bait in Portugal: harvesting, import and rearing management.info:eu-repo/semantics/publishedVersio
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