2,992 research outputs found
Segregação de recursos por diferentes espécies de morcegos (Mammalia: Chiroptera) na Reserva Biológica de Sooretama
Em ecologia, uma das ideias mais importantes é o princípio da exclusão competitiva, ou Lei de Gause, que afirma que duas espécies competindo pelos mesmos recursos não podem coexistir de modo estável se todos os outros fatores ecológicos forem constantes. Um dos competidores vai sobrepor-se ao outro, levando a um deslocamento evolutivo, morfológico ou comportamental, a um nicho ecológico diferente, ou mesmo à extinção. O horário de atividade diferenciado pode ser um importante fator para evitar competição por espécies proximamente relacionas, sendo assim motivo de interesse nos estudos de exclusão competitiva. O ciclo lunar é importante fator modulador de mamíferos noturnos, podendo também exercer influência na partilha de recursos, onde espécies relacionadas podem responder de diferentes maneiras à iluminação lunar. Analisar as diferenças no horário de atividade de espécies próximas de morcegos trará respostas sobre como uma comunidade partilha a disponibilidade de alimento sobre o critério de tempo. O objetivo foi testar a hipótese de que espécies próximas de morcegos usam o horário de atividade como fator de segregação de recursos. O estudo se deu na Reserva Biológica de Sooretama, importante fragmento de Mata Atlântica ombrófila densa localizada numa região plana no norte do estado do Espírito Santo. A hipótese foi descartada para os grupos de morcegos frugívoros, em análises intra e intergenéricas. Porém, para grupos de insetívoros e nectarívoros, a hipótese de segregação de recursos pelo variável tempo foi sustentada por todos os testes e análises, levando a crer que seja um fator importante nesses grupos
Pose consensus based on dual quaternion algebra with application to decentralized formation control of mobile manipulators
This paper presents a solution based on dual quaternion algebra to the
general problem of pose (i.e., position and orientation) consensus for systems
composed of multiple rigid-bodies. The dual quaternion algebra is used to model
the agents' poses and also in the distributed control laws, making the proposed
technique easily applicable to time-varying formation control of general
robotic systems. The proposed pose consensus protocol has guaranteed
convergence when the interaction among the agents is represented by directed
graphs with directed spanning trees, which is a more general result when
compared to the literature on formation control. In order to illustrate the
proposed pose consensus protocol and its extension to the problem of formation
control, we present a numerical simulation with a large number of free-flying
agents and also an application of cooperative manipulation by using real mobile
manipulators
Cytometric analysis, genetic manipulation and antibiotic selection of the snail embryonic cell line Bge from Biomphalaria glabrata, the intermediate host of Schistosoma mansoni.
The invertebrate cell line, Bge, from embryos of the snail Biomphalaria glabrata, remains to date the only established cell line from any species of the Phylum Mollusca. Since its establishment in 1976 by Eder Hansen, few studies have focused on profiling its cytometrics, growth characteristics or sensitivity to xenobiotics. Bge cells are reputed to be challenging to propagate and maintain. Therefore, even though this cell line is a noteworthy resource, it has not been studied widely. With growing interest in functional genomics, including genetic transformation, to elucidate molecular aspects of the snail intermediate hosts responsible for transmission of schistosomiasis, and aiming to enhance the convenience of maintenance of this molluscan cell line, we deployed the xCELLigene real time approach to study Bge cells. Doubling times for three isolates of Bge, termed CB, SL and UK, were longer than for mammalian cell lines - longer than 40 h in complete Bge medium supplemented with 7% fetal bovine serum at 25 °C, ranging from ∼42 h to ∼157 h when 40,000 cells were seeded. To assess the potential of the cells for genetic transformation, antibiotic selection was explored. Bge cells were sensitive to the aminonucleoside antibiotic puromycin (from Streptomyces alboniger) from 5 μg/ml to 200 ng/ml, displaying a half maximal inhibitory concentration (IC50) of ∼1.91 μg/ml. Sensitivity to puromycin, and a relatively quick kill time (<48 h in 5 μg/ml) facilitated use of this antibiotic, together with the cognate resistance gene (puromycin N-acetyl-transferase) for selection of Bge cells transformed with the PAC gene (puroR). Bge cells transfected with a plasmid encoding puroR were partially rescued when cultured in the presence of 5 μg/ml of puromycin. These findings pave the way for the development of functional genomic tools applied to the host-parasite interaction during schistosomiasis and neglected tropical trematodiases at large
Patterns of Musical Interaction with Computing Devices
In line with the efforts from the Ubiquitous Music Group, our research identified recurring patterns of interaction between humans and computing devices in existing music software and hardware. These four kinds of repeatedly implemented musical interactions are being documented in the form of interaction design patterns, providing an alternative taxonomy of interaction types, suitable for musical and computational developments in ubiquitous music research. In this paper we briefly describe the meaning of patterns in design fields. We also defend the use of interaction patterns in the design of ubiquitous music systems, and present the four proto-patterns proposed in our research. We intend with this paper to foster discussions at this 3rd Ubimus workshop, which can lead to refinement and improvement of the proposed interaction design patterns
Natural extracts from Pterospartum tridentatum at different vegetative stages: extraction yiels, phenolic content and antioxidant activity
The aerial parts of Pterospartum tridentatum, a wild growing species in Portugal used in
traditional medicine and gastronomy, were harvested at different stages (vegetative phase, flowering
phase and beginning of dormancy) in two locations in Portugal (Malcata and Gardunha mountains),
and the respective aqueous extracts have been studied. The influence of the seasonal variation in the
extraction yield, total phenolic content and antioxidant activity was evaluated. The extraction was
carried out in boiling water in consecutive steps. After each step, the aqueous extract was separated
and fresh water was added maintaining the same plant material. The procedure was repeated seven
times, within an overall time period of 180 minutes.
Higher extraction yields were achieved with plant stems collected at the vegetative phases, either from
Malcata or Gardunha regions. The total phenolic content of the extracts from Malcata plants ranged
from 273 mg to 400 mg gallic acid equivalent/g dry matter, which was quite similar to that determined
for extracts from Gardunha (245 to 394 mg gallic acid equivalent/g dry matter). The antioxidant activity
was determined by the radical scavenging activity method using 2,2-diphenyl-1-picrylhydrazyl radical
(DPPH). The greatest radical scavenging activity was observed in the flowers extracts, even though all
extracts produced presented a good antioxidant activity. Furthermore, the antioxidant activity was not
affected by the exposure of the plant material at 100ºC for long periods of time (180 min).
The results show that Pterospartum tridentatum has a great potential to be used as a new source of
natural antioxidants for the food industry
Gravitational diffraction radiation
We show that if the visible universe is a membrane embedded in a
higher-dimensional space, particles in uniform motion radiate gravitational
waves because of spacetime lumpiness. This phenomenon is analogous to the
electromagnetic diffraction radiation of a charge moving near to a metallic
grating. In the gravitational case, the role of the metallic grating is played
by the inhomogeneities of the extra-dimensional space, such as a hidden brane.
We derive a general formula for gravitational diffraction radiation and apply
it to a higher-dimensional scenario with flat compact extra dimensions.
Gravitational diffraction radiation may carry away a significant portion of the
particle's initial energy. This allows to set stringent limits on the scale of
brane perturbations. Physical effects of gravitational diffraction radiation
are briefly discussed.Comment: 5 pages, 2 figures, RevTeX4. v2: References added. Version to appear
in Phys. Rev.
Implementing structural fuses in CFRP components via microstructurally-engineered crack paths
This study aims to develop and implement actual carbon fibre-reinforced polymer (CFRP) solutions for realising structural fuses in real components. To this end, we have developed various concepts for structural fuses, applied to generic idealised components and aimed at engaging different in-plane and through-the-thickness damage propagation mechanisms. Micro-cut patterns (MCPs) / crack path combinations have been engraved on thin-ply CFRP prepregs (by using a laser cut machine) for manufacturing CFRP specimens. Afterwards, we have carried out a series of experimental studies to evaluate the fracture properties of various MCPs under three-point bending (3PB). Then, 3PB results were used to refine and down-select our concepts, for use in our generic idealised component design to test them under indentation test using a cantilever beam rig. The test results demonstrated that MCPs can provide significant control over the fracture locus and path, additionally allowing the failure initiation load and energy dissipation to be tailored
Utilização de carvão e subprodutos da carbonização vegetal na agricultura: aprendendo com as Terras Pretas de Índio.
A Carbonização Vegetal. Físico química da carbonização vegetal. Características e propriedades do carvão e de subprodutos da carbonização vegetal. Carvão. Alcatrão vegetal. Ácido pirolenhoso. A produção de carvão vegetal e subprodutos da carbonização vegetal no Brasil. Potencial produção de fertilizantes e condicionadores de solos a partir de carvão e subprodutos da carbonização vegetal. Síntese de ácidos húmicos a partir de carvão vegetal. Utilização de carvão na produção de fertilizantes orgânicos e substratos. Produção de condicionadores orgânicos. Utilização de fino de carvão como substrato para mudas. Próximos passos para a pesquisa, desenvolvimento e inovação
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