1,721,314 research outputs found
ASO Author Reflections: Prognostication in Early- and Advanced-Stage Small Bowel Adenocarcinomas
No full textGenetic variability in two populations of Hygrobates longipalpis Koch (Acari, Actinedida, Hgrobatidae)
No full textRecherches faunistiques et ecologiques sur les Hydracariens de l' Apennin (Italie). La genre Torrenticola, Piersig (Acari, Actinedida, Hydracnellae). Iere note
No full textHow does water current velocity affect invertebrate community and leaf-litter breakdown in a physicochemically stable freshwater ecosystem? An experimental study in two nearby reaches (erosional vs. depositional) of the Vera Spring (Central Italy)
Full text linkThe decomposition of allochthonous dead organic matter is a key process for the
metabolism and functioning of stream and spring ecosystems. The litter breakdown
process is influenced by several abiotic and biotic factors. Among abiotic parameters,
the role of current velocity and physical abrasion was poorly investigated. Field studies
gave contrasting results, mainly because of the covariation and the interaction of
current velocity with other biotic/abiotic variables. For these reasons, we assessed
leaf-litter breakdown and the structure of crenic assemblages in two nearby reaches
(erosional vs. depositional) of a physicochemically stable rheocrene spring. The two
zones investigated were characterized by similar environmental conditions, but water
current velocity was about four times greater in the erosional reach. We found substantial
differences in the structure and functional organization of crenic assemblages.
Overall taxa richness and density were higher in the depositional reach, while
diversity and abundance of Ephemeroptera, Plecoptera and Trichoptera were taller in
the erosional zone. Shredders were more abundant in the erosional zone, and
scrapers were more represented in the slow current sector of the spring. We also
demonstrated that water flow may promote a faster decomposition of leaf detritus in
the spring erosional reach mainly through indirect effects: higher richness and abundance
of shredder detritivores. Our results indicate that water current velocity may
have a key role in affecting both spring assemblage composition and ecosystem
processes
Brachypoda (Hemibrachipoda) baderi (Acari, Hydrachnellae, Aturidae) a new species from running waters of central Italy
No full textfisiopatologia dell'intestino tenue
No full texttrattato destinato agli studenti del corso di laurea in Medicina e Chirurgia. Nel capitolo si tratta dei meccanismi alla base dell'assorbimento e digestione
Comparisons between experimental tests and numerical simulations of a special transformer behavior
No full textNo post-drought recovery of the macroinvertebrate community after five months upon rewetting of an irregularly intermittent Apennine River (Aterno River)
No full textThe combined effects of global changes and increasing water demand for human use are the main drivers of the increasing intermittence of most watercourses. The disruption of lateral, longitudinal and vertical connectivity during the dry phase in newly intermittent rivers may have dramatic effects on freshwater biota, ecosystem structure and processes and may extend its influence also after several months from the return of superficial flow. A few studies have systematically documented the dynamics of post-drought recovery of freshwater communities. In this paper we assessed the temporal dynamics of benthic in- vertebrate’s recovery starting from the first day after superficial flow resumption and for the successive five months. We demonstrated that the recolonization process of rewetted substrata was very low and partial, and after five months from the return of superficial flow the richness and abundance of post-drought re-colonizers were markedly lower if compared with the pre-drought community and with that of a near upstream perennial site. In this context, upstream drift, “seedbanks”and hyporheic refugia would be of mi- nor importance and the observed recolonization pattern may be mainly explained by the aerial dispersal from downstream perennial reaches of tolerant and generalist taxa. There- fore, former perennial Apennine rivers may be profoundly affected by modifications of the natural flow regime. Increasing intermittence of these watercourses may determine drastic changes in community structure and composition, with species loss and species substitu- tion. In addition, the high post-drought functional turnover may have negative effects on key ecosystem processes as leaf-litter breakdown and primary production
Disease- and gender-related characteristics of coeliac disease influence diagnostic delay
No full text- …
