282 research outputs found
On Roth's theorem on progressions
We show that if A is a subset of {1,...,N} contains no non-trivial three-term
arithmetic progressions then |A|=O(N/ log^{1-o(1)} N). The approach is somewhat
different from that used in arXiv:1007.5444.Comment: 16 pp. Corrected the proof of the Croot-Sisask Lemma. Corrected
typos. Updated reference
Fractional flow reserve (FFR)-based therapy in patients presenting with acute coronary syndrome: Current data and everyday practice
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Fractional flow reserve (FFR) is an evidence-based diagnostic tool of physiological significance of coronary artery stenosis in patients with stable coronary artery disease (CAD). Due to microvascular dysfunction in acute coronary syndrome (ACS), information obtained from FFR assessment could be less reliable and, thus, its clinical role remains controversial. Indeed, results of currently published studies are essentially discrepant. Only a few randomized clinical trials have been performed showing the efficacy of FFR-guided percutaneous coronary intervention in ACS. Consequently, its role in acute scenarios remains substantially understudied. Herein, is presented the current state of knowledge reÂgarding FFR use in ACS setting. (Cardiol J 2017; 24, 4: 426–435
Organizational Practices Leading to a Positive Safety Culture: A Delphi Approach
A positive safety culture has been shown to contribute to a firm\u27s ability to avoid or reduce the occurrence of occupational accidents and injuries. In American workplaces alone 3,582 people died and 5.1 million people were disabled in 2009 and the cost to corporate America was 1,200. Firms that establish and maintain a positive safety culture are able to achieve a competitive advantage in the market.
While much research exists showing the relationship between safety culture and accident reduction, less guidance is found on how companies might achieve such improvement through cultural change. Attempts have been made to determine the factor structure of safety culture, that is, the identification of the antecedents of a positive safety culture. However, to date no general consensus has emerged among researchers about the exact elements of the factor structure. Research methodologies have been blamed for biasing the research results and thereby causing the lack of consensus. This dissertation uses a different methodology, the Delphi method combined with Hofstede\u27s well-known onion model of organizational culture, to determine those organizational practices that lead to a positive safety culture.
Delphi is a mixed methodology that begins with an exploratory approach followed by the more traditional quantitative method. The exploratory front-end was deemed appropriate given that prior traditional survey instruments most likely introduced researcher bias through a myopic view of safety culture. Delphi also differs by utilizing purposeful sampling versus random sampling which provides a high level of expertise to inform the research.
After four rounds of inquiry with a panel of experts, a consensus was reached on 18 organizational practices that lead to a positive safety culture. This research adds to the understanding of safety culture, provides useful information for both practitioners and academic researchers, and offers launch points for extensions of the research
Assessment of ocean prediction model for Naval Operations using acoustic preset
OCEANS2005, MTS/IEEE Conference Proceedings, DVD-ROMThe outcome of a battlefield engagement is
often determined by the advantages and disadvantages held
by each adversary. On the modern battlefield, the possessor
of the best technology often has the upper hand, but only if
that advanced technology is used properly and efficiently. In
order to exploit this advantage and optimize the effectiveness
of high technology sensor and weapon systems, it is essential
to understand the impact on them by the environment. In the
arena of Anti-Submarine Warfare (ASW), the ocean
environment determines the performance of the acoustic
sensors employed and the success of any associated weapon
systems. Since acoustic sensors detect underwater sound
waves, understanding how those waves propagate is crucial
to knowing how the sensors will perform and being able to
optimize their performance in a given situation. To gain this
understanding, an accurate depiction of the ocean
environment is necessary. How acoustic waves propagate
from one location to another under water is determined by
many factors, some of which are described by the sound
speed profile (SSP). If the environmental properties of
temperature and salinity are known over the entire depth
range, the SSP can be compiled by using them in an
empirical formula to calculate the expected sound speed in a
vertical column of water. One way to determine these
environmental properties is to measure them in situ, such as
by conductivity-temperature-depth or expendable
bathythermograph (XBT) casts. This method is not always
tactically feasible and only gives the vertical profile at one location producing a very limited picture of the regional
ocean structure. Another method is to estimate the ocean
conditions using numerical models. The valued-aided
ocean prediction models to ASW is assessed in this study.
Such quantitative analyses offer a means to optimize the
ASW requirements and technical capabilities of new weapon
systems. We use observed and modeled 3-D fields of
temperature, salinity, and sound speed. Compare model
profiles to observed profiles. Do ocean models predict the
vertical features of the observational data? Run
representative modeled and observed SSP profiles through
Navy’s acoustic models to see if there is an acoustic
difference in propagation and weapon preset
Position Estimation in Mixed Indoor-Outdoor Environment Using Signals of Opportunity and Deep Learning Approach
To improve the user's localization estimation in indoor and outdoor environment a novel radiolocalization system using deep learning dedicated to work both in indoor and outdoor environment is proposed. It is based on the radio signatures using radio signals of opportunity from LTE an WiFi networks. The measurements of channel state estimators from LTE network and from WiFi network are taken by using the developed application. The user's position is calculated with a trained neural network system's models. Additionally the influence of various number of measurements from LTE and WiFi networks in the input vector on the positioning accuracy was examined. From the results it can be seen that using hybrid deep learning algorithm with a radio signatures method can result in localization error 24.3 m and 1.9 m lower comparing respectively to the GPS system and standalone deep learning algorithm with a radio signatures method in indoor environment. What is more, the combination of LTE and WiFi signals measurement in an input vector results in better indoor and outdoor as well as floor classification accuracy and less positioning error comparing to the input vector consisting measurements from only LTE network or from only WiFi network
Fungi isolated from phyllosphere of fodder galega (Galega orientalis)
The object of the experiment was fodder galega (Galega orientalis Lam.) cultivated in 2001-2003 as field crop on three plots: 1. without fertilization, 2. 40 kg P2O5 × ha-1 and 80 kg K2O × ha-1, 3. 80 kg P2O5 × ha-1 and 160 kg K2O × ha-1. During the dry and warm vegetation season of 2002 almost two times fewer isolates were obtained from the leaves than in 2003 that was the most abundant in fungi. Yeasts-like fungi (30% of the total number of isolates) and saprotrophic fungi with dominated species: Acremonium strictum (8.5%), genus Epicoccum (7.8%), Humicola (9.5%) and Penicillium (18.9%) were the fungi most frequently populating the leaves of galega. The share of pathogens in the total number of isolates obtained from the phyllosphere was 10.6%. They were represented by fungi of Ascochyta spp., Botrytis cinerea, genus Fusarium, Phoma medicaginis and Sclerotinia sclerotiorum. Reduction by 1.9 to 4.6% in the number of fungi isolated from the phyllosphere of galega without fertilization as compared to galega cultivated in combinations with fertilization was recorded. Generally, the smallest number of pathogens was recovered from galega fertilized with 40 kg P2O5 × ha-1 and 80 kg K2O × ha-1. B. cinerea most frequently populated galega in combination without fertilization, genus Fusarium fungi in combination without fertilization and with fertilization with 80 kg P2O5 × ha-1 and 160 kg K2O × ha-1, while Ascochyta spp. were isolated from galega with fertilization only
Fungi colonizing the soil and roots of tomato (Lycopersicum esculentum Mill.) plants treated with biological control agents
Tomato plants, cv. Rumba Ożarowska, grown in the greenhouse of the University of Warmia and Mazury, were protected in the form of alternate spraying (twice) and watering (twice) with 5% aqueous extracts of the following plant species: Aloe vulgaris Lam., Achillea millefolium L., Mentha piperita L., Polygonum aviculare L., Equisetum arvense L., Juglans regia L. and Urtica dioica L. Plants not treated with the extracts served as control. After fruit harvest, samples of roots and soil were collected. The roots were disinfected and next placed on PDA medium. Soil-colonizing fungi were cultured on Martin medium. Fungi were identified microscopically after incubation. Pathogenic fungal species, Colletotrichum coccodes, Fusarium equiseti, F. oxysporum and F. poae, accounted for over 60% of all isolates obtained from the roots of tomato plants. The soil fungal community was dominated by yeast-like fungi (75.4%), whereas pathogenic fungi were present in low numbers. The applied 5% aqueous plant extracts effectively reduced the abundance of fungi, including pathogenic species, colonizing tomato plants and soil. The extract from P. aviculare showed the highest efficacy, while the extract from J. regia was least effective. Fungi showing antagonistic activity against pathogens (Paecilomyces roseum and species of the genus Trichoderma) were isolated in greatest abundance from the soil and the roots of tomato plants treated with A. millefolium, M. piperita and U. dioica extracts
The study of leptin concentration in saliva during orthodontic treatment, periodontal diseases and wound healing in the oral mucosa-review
Background
The oral cavity is a very complex environment characterized by numerous interactions between different tissues, secretions from various glands, foods, air and microorganisms. Leptin is a hormone-like protein, which plays an important role in protection of host against inflammation and infection. It exhibits many physiological properties. Some studies have reported changes in leptin levels during orthodontic treatment, wound healing, periodontal disease. The aim of the paper was to review the salivary leptin role in each of these cases.
Methods
Articles published before November 2018 were obtained from PubMed, Dentistry & Oral Sciences Source. Inclusion criteria were: a) empirically based b) peer-reviewed.
Discussion and results
Salivary leptin levels significantly decrease during orthodontic tooth movement and periodontal diseases. However, it increases while wound healing in the oral mucosa.
Conclusion
There is a correlation between tooth movement and leptin level. Obese patients could have lesser tooth movement. This hormone promotes wound healing and angiogenesis in oral cavity. Leptin concentration in saliva increases in patients with periodontitis
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