148 research outputs found
Importà ncia biològica dels alcaloides per a les plantes
In contrast with animals, plants respond to their environment by sinthesising a large
array of secondary compounds with very different chemical properties and uses. The most
interesting group of natural products is alkaloids, of wich about six thousand are well known
and have been found to be distributed among many plant families. The roles of alkaloids
in plant metabolism or plant physiology are supposed to be growth regulators, storage reservoirs
of nitrogen, end products of metabolism or waste products, or plant-protecting
agents toward parasites and competitors or against attack by predators
The Genus Galanthus: A Source of Bioactive Compounds
The Amaryllidaceae family is one of the 20 most important alkaloid-containing plant
families (Zhong, 2005). It comprises about 1100 perennial bulbous species classified in 85
genera, distributed throughout the tropics and warm temperate regions of the world (Willis,
1988). The specific alkaloids produced by the amaryllidaceous plants have attracted
considerable attention due to their interesting pharmacological activities. One of them,
galanthamine, is a long acting, selective, reversible and competitive inhibitor of the
acetylcholinesterase enzyme (Thomsen et al., 1998), which is marketed as a hydrobromide
salt under the name of Razadyne® (formerly Reminyl®) and Nivalin® for the treatment of
Alzheimer’s disease, poliomyelitis and other neurological diseases (Heinrich and Teoh,
2004). After its discovery in Galanthus woronowii by Proskurina and co-authors in 1955
(Proskurina et al., 1955), the pharmacological properties of galanthamine soon attracted the
attention of the pharmaceutical industry. It was first produced by Sopharma (Bulgaria)
under the name of Nivalin® from G. nivalis in the early 1960s, but due to the small plant size
and variability of galanthamine content, this species was soon replaced by other plant
sources (Berkov et al., 2009b).
The genus Galanthus (Snowdrop; Greek gála "milk", ánthos "flower") comprises about 19
species (World Checklist of Selected Plant Families), and to our knowledge 11 have been
investigated for their alkaloid content. Although the genus has only been partially studied,
phytochemical work has revealed an exceptional diversity of alkaloid structures, many of
them reported for the first time and with still unknown bioactivity. The present article
provides a brief overview of the phytochemical studies within the genus Galanthus
Issue networks on the Web:Â a proposal of components and characterization
Para muchos tipos de investigaciĂłn en ciencias sociales, polĂticas o de mercado, existe la necesidad de obtener informaciĂłn sobre la opiniĂłn o la reacciĂłn pĂşblica ante determinados temas. La web es una fuente de informaciĂłn que puede ayudar a satisfacer esta necesidad, pero para conseguir este objetivo es necesario desarrollar conceptos y metodologĂas que nos permitan entender su funcionamiento y extraer las diferentes formas de conocimiento que contiene. En este artĂculo presentamos el concepto de “red temática”; y a travĂ©s de una revisiĂłn teĂłrica de los estudios de hiperenlaces, de los conceptos de tema y actor y del propio concepto de red temática, exponemos sus caracterĂsticas, la problemática que resuelve y las posibilidades que ofrece a los estudios de opiniĂłn.Many types of research on Social Sciences, Political Sciences and Market Sciences present the need to obtain information about the opinion or public reaction to certain topics. The Web is a source of information which might help satisfying this need, but to achieve this goal it is necessary to develop concepts and methodologies allowing to understand how it works, and to extract the different forms of knowledge it contains. This article presents the concept of “issue network”, and through a theoretical revision of hyperlink studies, the concepts of “issue” and “actor” and the concept of issue network itself, we expose its characteristics, the problems it solves and the possibilities it offers to opinion studies
Evolució històrica de l'ús dels alcaloides com agents terapèutics
Les relacions de l'home amb el medi vegetal, en aquest cas amb finalitats curatives, té una llarga història i forces perspectives de futu
Itineraris arquitectònics de Solsona (1875-1936)
El projecte de final de grau “I tinerari s Arqui tectònics de Solsona 1875-1936” neix
amb la idea d’ompli r un bui t i aprofundi r sobre l’estudi de l'arqui tectura durant
aquest perĂode. Hi havia, i hi ha encara, un vast camp de possibi li tats de recerca
de les construccions solsonines del s segles XIX i XX. Sol sona Ă©s una ciutat marcada
per la història i conserva un rellevant conjunt patrimonial . Per aquest motiu,
tradicionalment els estudis sobre arquitectura s’han centrat principalment en el
llegat medieval i barroc, deixant de banda l’arquitectura més contemporà nia.
Amb aquesta recerca que presentem, volem aprofundi r en el coneixement històric
de l’arqui tectura sol sonina, a parti r de la fi de les guerres carlines. Ho hem fet des
d'una perspectiva à mplia, sense descuidar l'anà lisi arqui tectònica, però
relacionant-la en tot allò que l'envol ta; en la mesura que podem, fem
protagonistes als personatges que han intervingut a la ciutat: per una banda, els
arquitectes que per diferents motius hi han reali tzat projectes, i per l’altra, els
mestres d’obres i el s diferents oficis relacionats amb la construcció que hi havia a
Solsona. Hem cregut mol t enriquidor poder veure aquests personatges dins el
llegat solsonĂ, però tambĂ© entendre’ls en les obres que han projectat fora de
Solsona.
TenĂem poques guies a seguir (autoria, dataciĂł, estudi ) del patrimoni arqui tectònic
sol sonĂ . Alguns estudis, informes i llibres havien iniciat el camĂ, per exemple, el
catĂ leg general del pla urbanĂstic. Alguns estudiosos havien esmerçat hores de
recerca en arxius i havien narrat part de l’arqui tectura i la història local que
coneixen (he intentat que les referències bibliogrà fiques del text mostrin aquest
esforç). Un gest que agraeixo, mol t especialment a Mossèn Enric Bartrina i Jaume
Cuadrench. I a Jaume Rosell i Ramon Graus que m’han fet entendre mol ts lligams
entre l’arqui tectura particular estudiada i els grans projectes i corrents de paĂs. El
treball que teniu a les mans, doncs, és un estudi en bona part inèdi t que suposa
aprofundir en una mostra de l’arqui tectura d’aquest perĂode a la ciutat.
És un treball fonamentat en la recerca de la documentació arquitectònica textual
i grĂ fica que es conserva d’aquest perĂode. La descoberta realitzada ens permet
inventariar l 'arqui tectura d'aquells anys i, a la vegada, conèixer els sistemes
constructius d’aquella època, la forma de gestionar els pressupostos i
econòmicament l’obra, les patologies del s materials... en defini tiva, el
paral·lelisme entre els processos que hem estudiat, uti li tzats a l’actuali tat, amb
aquells que s’empraven antigament. Per interveni r en el patrimoni arquitectònic
que conservem és fonamental conèixer i comprendre els edificis; els seus
materials, les seves formes. Si en coneixem el tot i sabem apreciar el detall, la
nostra feina serà mol t més preci sa i posi tiva pel conjunt
Use of generative artificial intelligence in the training of journalists: challenges, uses and training proposal
Artificial Intelligence (AI) is already integrated into news production strategies in some media outlets. Recently, generative AIs like ChatGPT and others have demonstrated their ability to enhance productivity in content production tasks, raising the question of how journalism faculties can address this new technology. This paper presents an academic study on the application of AI in higher communication studies. The study involved 4 in-depth interviews and 28 semi-structured interviews with university lecturers and researchers. The findings confirm varying degrees of convergence and divergence on different aspects of the technology, including the integration of AI in communication faculties, student training in AI usage, the introduction of AI and journalism as a subject area, and the potential uses of AI in news production and consumption. Additionally, this paper proposes a comprehensive training program on AI and journalism, focusing on its foundations, technical competencies, and ethical considerations
A sample design proposal for the analysis of Twitter in political communication
Based on an analysis of several sampled political discussions on Twitter, a new methodology is proposed that allows researchers to obtain a significant, replicable, and manageable data sample from a universe of Twitter metadata. The proposal is a new model called Top discussion indicator (TDI). The aim of TDI is to assist researchers in obtaining a representative set of text from Twitter that includes the minimum amount of information needed to generalize the results
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