21 research outputs found
A reduced, yet functional, nectary disk integrates a complex system of floral nectar secretion in the genus Zeyheria (Bignoniaceae)
Harmful Elements in Estuarine and Coastal Systems
Estuaries and coastal zones are dynamic transitional systems which provide many economic and ecological benefits to humans, but also are an ideal habitat for other organisms as well. These areas are becoming contaminated by various anthropogenic activities due to a quick economic growth and urbanization. This chapter explores the sources, chemical speciation, sediment accumulation and removal mechanisms of the harmful elements in estuarine and coastal seawaters. It also describes the effects of toxic elements on aquatic flora and fauna. Finally, the toxic element pollution of the Venice Lagoon, a transitional water body located in the northeastern part of Italy, is discussed as a case study, by presenting the procedures adopted to measure the extent of the pollution, the impacts on organisms and the restoration activities
Geometric Configuration of the Anatomical Theater of Padua
This contribution deals with a study carried out on the Anatomical Theater of Padua (built in 1595). Historical documentation research and digital survey advantage the understanding not only the design idea but also its geometric rules of the configuration, through a schematic elaboration based on the digital model
Le opportunit\ue0 fornite dai nuovi strumenti digitali = The opportunities of the new digital tools
Questo saggio, tratta la rappresentazione delle
citt\ue0 focalizzandosi sulle trasformazioni storiche
e si affida agli strumenti di scansione digitale,
alla modellazione 3D e alle tecnologie di Realt\ue0
Aumentata (AR). Il materiale trattato proviene
da un progetto intitolato Visualizing Venice, una
cooperazione internazionale multi-istituzionale
che da poco tempo \ue8 passata a Visualizing Cities.
La sfida principale di Visualizing Cities \ue8 descrivere
in maniera digitale come le citt\ue0 - con le loro
architetture - evolvano e cambiano nel tempo,
utilizzando modelli digitale 4D interoperabili,
collegati a fonti esterne documentali
Flower morphology, nectar features, and hummingbird visitation to Palicourea crocea (Rubiaceae) in the Upper Paraná River floodplain, Brazil
We investigated flower morphology, nectar features, and hummingbird visitation to Palicourea crocea (Rubiaceae), a common ornithophilous shrub found in the riparian forest understory in the Upper Paraná River floodplain, Brazil. Flowers are distylous and the style-stamen dimorphism is accompanied by other intermorph dimorphisms in corolla length, anther length, and stigma lobe length and form. We did not observe strict reciprocity in the positioning of stigma and anthers between floral morphs. Flowering occurred during the rainy season, October to December. Nectar standing crop per flowerwas relatively constant throughout the day, which apparently resulted in hummingbirds visiting the plant throughout the day. Energetic content of the nectar in each flower (66.5J) and that required daily by hummingbird visitors (up to 30kJ) would oblige visits to hundreds of flowers each day, and thus movements between plants that should result in pollen flow. Three hummingbird species visited the flowers: the Gilded Sapphire (Hylocharis chrysura), the Black-throated Mango (Anthracothorax nigricollis), and the Glittering-bellied Emerald (Chlorostilbon aureoventris). The frequency of hummingbird visitation, nectar features, and the scarcity of other hummingbird-visited flowers in the study area, indicate that P. crocea is an important nectar resource for short-billed hummingbirds in the study site.<br>Investigamos a morfologia floral, as características do néctar e a visita de beija-flores a Palicourea crocea (Rubiaceae), uma espécie ornitófila arbustiva comumente encontrada no sub-bosque da vegetação ripária na planície de inundação do Alto Rio Paraná, Brasil. As flores são distílicas, sendo o dimorfismo estilete-estames acompanhado por outras variações morfológicas no comprimento da corola, altura das anteras, comprimento das anteras e comprimento e forma das papilas estigmáticas. Não foi observada reciprocidade estrita na posição dos estigmas e anteras entre flores longistilas e brevistilas. A floração da espécie ocorreu durante a estação chuvosa, de outubro a dezembro. A disponibilidade de néctar foi relativamente constante ao longo do dia, o que aparentemente possibilitou aos beija-flores visitar a planta o dia todo. O conteúdo energético de néctar por flor (66,5J) e a demanda diária de energia dos beija-flores visitantes(superior a 30kJ) os obrigaria a visitar diariamente centenas de flores da espécie, o que pode aumentar o fluxo de pólen. Três espécies de beija-flores foram observadas: beija-flor-dourado (Hylocharis chrysura), beija-flor-de-colete-preto ( Anthracothorax nigricollis) e esmeralda-de-bico-vermelho ( Chlorostilbon aureoventris). A freqüência de visita dos beija-flores, as características do néctar e a baixa disponibilidade de outras flores visitadas por beija-flores na área de estudo indicam que P. crocea é uma fonte de néctar importante para beija-flores de bico-curto no local
Auto-pollination in a long-spurred endemic orchid (Jumellea stenophylla) on Reunion Island (Mascarene Archipelago, Indian Ocean)
The Evolution and Pollination of Oceanic Bellflowers (Campanulaceae)
11 p., tablas, gráf.Oceanic islands provide a good model for the study of species dispersal and evolution. We focus here on the evolution of pollination modes of oceanic island bellflowers (Campanulaceae), examining the degree of parallel evolution in different lineages of this family. Plants colonizing islands might either have experienced selective pressures on floral traits from vertebrate pollinators such as birds and lizards or have been pre-adapted to pollination by vertebrates prior to their colonization. The reconstruction of the ancestral pollination biology of Campanulaceae suggests that pollinators of the ancestors of bird-/lizard-pollinated bellflowers were insects. Moreover, in four island Campanulaceae lineages, only one was pre-adapted on the continent, and three made de novo shifts on the islands. Evolution towards bird pollination from insect-pollinated ancestors is also common in other island-groups, possibly because opportunistic birds are more efficient than insects. We review to what extent related species converge in their pollination ecology in related habitats on oceanic islands.Peer reviewe