Search results for "DOI"
showing 10 items of 236 documents
The chemical composition of the aerial parts of Stachys spreitzenhoferi (Lamiaceae) growing in Kythira Island (Greece), and their antioxidant, antimi…
2022
The Stachys L. genus has been used in traditional medicine to treat skin inflammations, stomach disorders, and stress. The aim of this study was to investigate the chemical profile and biological activity of the methanolic extract of Stachys spreitzenhoferi Heldr. (Lamiaceae) aerial parts, collected on the island of Kythira, South Greece. The analysis by liquid chromatography coupled with electrospray ionization and high-resolution mass spectrometry [LC-(-)ESI/HRMSn] of the methanol extract revealed the occurrence of thirty-six compounds - flavonoids, phenylethanoid glycosides, iridoids, quinic acid derivatives, aliphatic alcohol glycosides, and oligosaccharides - highlighting the substanti…
A fast and recursive algorithm for clustering large datasets with k-medians
2012
Clustering with fast algorithms large samples of high dimensional data is an important challenge in computational statistics. Borrowing ideas from MacQueen (1967) who introduced a sequential version of the $k$-means algorithm, a new class of recursive stochastic gradient algorithms designed for the $k$-medians loss criterion is proposed. By their recursive nature, these algorithms are very fast and are well adapted to deal with large samples of data that are allowed to arrive sequentially. It is proved that the stochastic gradient algorithm converges almost surely to the set of stationary points of the underlying loss criterion. A particular attention is paid to the averaged versions, which…
Terpenoid glycosides from the root's barks of Eriocoelum microspermum Radlk. ex Engl.
2018
Abstract Eight undescribed triterpenoid saponins together with a known one, and two undescribed sesquiterpene glycosides were isolated from root's barks of Eriocoelum microspermum. Their structures were elucidated by spectroscopic methods including 1D and 2D experiments in combinaison with mass spectrometry as 3-O-α-L-rhamnopyranosyl-(1 → 3)-[α-L-rhamnopyranosyl-(1 → 2)]-α-L-arabinopyranosylhederagenin, 3-O-α-L-rhamnopyranosyl-(1 → 3)-[β-D-glucopyranosyl-(1 → 3)-α-L-rhamnopyranosyl-(1 → 2)]-α-L-arabinopyranosylhederagenin, 3-O-α-L-rhamnopyranosyl-(1 → 3)-[β-D-xylopyranosyl-(1 → 3)-α-L-rhamnopyranosyl-(1 → 2)]-α-L-arabinopyranosylhederagenin, 3-O-α-L-rhamnopyranosyl-(1 → 4)-[α-L-rhamnopyrano…
Regional heterogeneity in the business environment: the case of Italy
2022
How do we evaluate the business environment of regional economies? This paper makes use of primary data from the World Bank’s Subnational Doing Business studies to analyze the capacity of Italian regions to facilitate entrepre- neurs in setting up and operating new businesses. By comparing data across locations and over time, we are able to identify best practices that may help policy makers in the implementation of reforms aiming at improving the business environ- ment of Italian regions and, as a result, of the country.
Learning by doing. Case study: Education for sustainable development at the University of Latvia
2019
Junction of possibilities offered by European research programmes in the tertiary education and technology enhanced learning open up new borders for students and young researchers; especially for the ones from institutions with less strong collaboration links to Western-Europe and overseas. University of Latvia has undertaken the challenge of designing master’s programme on education for sustainable development called ‘Natural Sciences, Global Change and Technologies for Sustainable Development’ combined with application of digital learning tools. Teaching staff was formed form several faculties of the University of Latvia, other universities, respective companies as well as foreign partner…
Oleuropein protects against dextran sodium sulfate-induced chronic colitis in mice.
2013
The anti-inflammatory effect of oleuropein (1), the major phenolic secoiridoid in Olea europaea, was evaluated in an experimental model of chronic colitis in mice. Animals were exposed to four repeated cycles of dextran sodium sulfate in drinking water followed by a 7-day rest period. Animals receiving a standard diet supplemented with 0.25% of 1 (equivalent to 500 mg/kg/day) for 56 days exhibited a decrease of inflammatory symptoms, as reflected by improvement of disease activity index and histopathological changes. It was found that 1 decreased inflammatory cell recruitment and the release of inflammatory cytokines interleukin (IL)-1β and IL-6 with increased IL-10 levels in colon tissue. …
Engaging universities in social innovation research for understanding sustainability issues
2017
International audience; The paper presents the analysis of a three-stage research conducted by the authors within a social innovation project in collaboration with international master students of Riga Technical University for determining the factors, which motivate people to be involved in the solution of social problems. The authors not only analyse and use the outcomes of the students’ research but also provide feasibility study of using the potential of study research at the university, for implementing serious research projects. Data collection from Africa, Asia, America and Europe was organised jointly by all the students via web-based survey for creating an original data base for the…
Tiešsaistes Klientu Segmentācija, Izmantojot Klasterizācijas Metodes
2021
Bakalaura darba mērķis ir izpētīt tiešsaistes klientu segmentāciju, lai tā palīdzētu pieņemt loģiskus lēmumus par efektīvu mārketinga un reklāmas resursu izmantošanu. Darbā tika izmantotas divas klasterizācijas metodes: K-Medoīdu (K-Medoids) klasterizācija, un K-Prototipu (K-Prototypes) klasterizācija. Metožu izvēle tiek pamatota ar pētītā uzdevuma raksturojumu. Darba gaitā tiek aprakstīti gan abu metožu teorētiskie aspekti, gan metodes tiek pielietotas praktiski (izmantojot programmu R) konkrēta uzdevuma risināšanai. Tika veikta iegūto rezultātu analīze un salīdzināšana. Bakalaura darbā tika arī paskaidrota klientu segmentācijas nozīme veiksmīgam uzņēmumam, kā arī tika aprakstīts interneta…
Impact of e-government on transaction cost and FDI inflows: A proposed conceptual framework
2011
Published version of an article in International Journal of Business and Management, 6(11), 285-296. Also available from the publisher at http://dx.doi.org/10.5539/ijbm.v6n11p285 Although vast normative e-government literature supports the assertion that implementation of e-government reduces transaction cost and promotes Foreign Direct Investment; empirical evidence to support this thesis is limited. Even more, there is limited attempt when studying this phenomenon to integrate e-government literature with other literatures in which major constructs of interest are rooted. This article contributes to reducing this gap by establishing a conceptual framework that integrates e-government lite…
The functionalization of nanodiamonds (diamondoids) as a key parameter of their easily controlled self-assembly in micro- and nanocrystals from the v…
2014
We detail herein readily accessible processes to control previously unobserved robust self-assemblies of nanodiamonds (diamondoids) in micro- and nanocrystals from their mild vapor deposition. The chemical functionalization of uniform and discernible nanodiamonds was found to be a key parameter, and depending on the type of functional group (hydroxy, fluorine, etc.) and its position on the diamondoid, the structure of the discrete deposits can vary dramatically. Thus, well-defined anisotropic structures such as rod, needle, triangle or truncated octahedron shapes can be obtained, and self-assembled edifices of sizes ranging from 20 nm to several hundred micrometers formed with conservation …