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showing 10 items of 1907 documents
Latvijas Vēstures Institūta Žurnāls. 2012, Nr. 2 (83)
2012
Valsts pētījuma programma "Nacionālā identitāte: valoda, Latvijas vēsture, kultūra un cilvēkdrošība"
Humusica 2, article 19: Techno humus systems and global change - Conservation agriculture and 4/1000 proposal
2018
International audience; Philosophy can overlap pedology. It is not casual that life begins and finishes in the soil. We separated the concepts of Humipedon, Copedon and Lithopedon. Some sections were dedicated to the founders of the movement for a new type of agriculture (agroecology). They simply proclaim to accompany the process of natural evolution instead of spending a lot of energy in hunting competitor organisms with pesticides or boosting the soil with mineral fertilisation and tillage. The core of the article is built on a biological concept of the soil and shows researches supporting this view. After pointing to the soil structure and illustrating its natural genesis, explaining wh…
Analysis of drought and vulnerability in the North Darfur region of Sudan
2018
North Darfur of Sudan is located on the edge of the Sahara Desert and endures frequent droughts due to water shortages and high summer temperatures. Monitoring and understanding drought characteristics are essential for integrated drought risk mitigation and prevetion of land degradation. This study evaluates drought conditions in North Darfur by analyzing the spatiotemporal distribution of drought using three drought indices (Standardized Precipitation Index, Vegetation Condition Index, and Soil Moisture Content Index) and their combined drought index (CDI) from 2004 to 2013. Biophysical and socioeconomic indicators are further used to measure vulnerability to drought risk and its three co…
Reevaluating the Role of Organic Matter Sources for Coastal Eutrophication, Oligotrophication, and Ecosystem Health
2019
Organic matter (OM) in aquatic systems is either produced internally (autochthonous OM) or delivered from the terrestrial environment (ter-OM). For eutrophication (or the reverse – oligotrophication), the amount of autochthonous OM plays a key role for coastal ecosystem health. However, the influence of ter-OM on eutrophication or oligotrophication processes of coastal ecosystems is largely unclear. Therefore, ter-OM, or ter-OM proxies are currently not included in most policies or monitoring programs on eutrophication. Nevertheless, ter-OM is increasingly recognized as a strong driver of aquatic productivity: By influencing underwater light conditions and nutrient- and carbon availability,…
Sugiyamaella mastotermitis sp. nov. and Papiliotrema odontotermitis f.a., sp. nov. from the gut of the termites Mastotermes darwiniensis and Odontote…
2016
Two novel yeast species were isolated from the guts of two different termite species. A new member of the genus Sugiyamaella was isolated from the hindgut and nest material of the lower Australian termite Mastotermes darwiniensis. The second novel yeast species, isolated from the higher termite Odontotermes obesus, was identified as a member of the genus Papiliotrema. Both yeast species were able to hydrolyse xylan, methylumbelliferyl β-xylobiose and methylumbelliferyl β-xylotriose. The ability to debranch different hemicellulose side chains and growth without the addition of external vitamins was observed. A symbiotic role of the novel yeast species is indicated, especially in respect to x…
Trail-following pheromones in basal termites, with special reference to Mastotermes darwiniensis
2007
0098-0331 (Print) Journal Article; In the framework of an evolutionary study, trail pheromones have been studied in the most basal extant termite, Mastotermes darwiniensis (Mastotermitidae), and two other basal termites, the Termopsidae Porotermes adamsoni (Porotermitinae) and Stolotermes victoriensis (Stolotermitinae). Although workers of M. darwiniensis do not walk in single file while exploring a new environment under experimental conditions and are unable to follow artificial trails in 'open field' experiments, they do secrete a trail-following pheromone from their sternal glands. This unique behavior might reflect a primitive function of communication of the sternal gland. The major co…
The phylogeny of termites (Dictyoptera : Isoptera) based on mitochondrial and nuclear markers : implications for the evolution of the worker and pseu…
2008
A phylogenetic hypothesis of termite relationships was inferred from DNA sequence data. Seven gene fragments (12S rDNA, 16S rDNA, 18S rDNA, 28S rDNA, cytochrome oxidase I, cytochrome oxidase II and cytochrome b) were sequenced for 40 termite exemplars, representing all termite families and 14 outgroups. Termites were found to be monophyletic with Mastotermes darwiniensis (Mastotermitidae) as sister group to the remainder of the termites. In this remainder, the family Kalotermitidae was sister group to other families. The families Kalotermitidae, Hodotermitidae and Termitidae were retrieved as monophyletic whereas the Termopsidae and Rhinotermitidae appeared paraphyletic. All of these result…
Influence of Riverine Input on Norwegian Coastal Systems
2020
Coastal ecosystems are of high ecological and socioeconomic importance and are strongly influenced by processes from land, sea, and human activities. In this study, we present physical, chemical, and biological observations over two consecutive years from three study regions along the Norwegian coast that represent a broad latitudinal gradient in catchment and oceanographic conditions (∼59–69°N): outer Oslofjord/southern Norway, Runde/western Norway, and Malangen/northern Norway. The observations included river monitoring, coastal monitoring, and sensor-equipped ships of opportunity (“FerryBox”). The riverine discharge and transports were an order of magnitude higher, and the spatiotemporal…
Sex pheromones and trail-following pheromone in the basal termites Zootermopsis nevadensis (Hagen) and Z. angusticollis (Hagen) (Isoptera: Termopsida…
2010
In the context of an evolutionary study of the chemical communication in termites, sex pheromones and trail-following pheromones were investigated in two Termopsidae, Zootermopsis nevadensis and Z. angusticollis. In these species, in which the presence of sex-specific pheromones has been demonstrated previously, the chemical structure of the female sex pheromone has now been identified as (5E)-2,6,10-trimethylundeca-5,9-dienal and the male sex pheromone as (+)- or (-)-syn-4,6-dimethyldodecanal. The amount of sex pheromone was estimated at 5-10 ng per individual in females and 2-5 ng in males. Because these two sympatric species do not differ in their pheromonal chemical composition, reprodu…
A reconciliation with Darwin? Divergent views on evolutionism in Erich Wasmann and Jaime Pujiula, biologists and Jesuits
2016
A diferencia del cas Galileu, l’esglesia Catolica ha gestionat amb discrecio el pensament evolucionista i les obres de Charles Darwin. Entre els cientifics catolics, hi trobem defensors d’un evolucionisme amanit amb remarcables excepcions relacionades amb l’origen divi de la vida i de l’especie humana. L’entomoleg i jesuita Erich Wasmann arriba a la conclusio que la teoria evolutiva podia donar explicacio a les seues observacions sobre els mirmecofils i adopta un evolucionisme catolicament matisat que Ernst Haeckel considerava fraudulent pero molt perillos. El bioleg i jesuita catala Jaume Pujiula segui l’obra de Wasmann tot i prenent posicions ideologiques mes radicals que la de l’entomole…