In the northeastern region of the Brazilian state of Pará, approximately 90% of the forested areas are secondary forests. Secondary forests are interesting areas for floristic studies aimed at determining the effects that clear-cutting has on bryophyte communities. The aim of this study was to compare upland forests at different successional stages and the various strata of host trees, in terms of the bryophyte species composition. Bryophyte specimens were collected between August 2005 and September 2006 from host trees in primary and secondary forests of different ages and of different heights, within the municipality of Capitão Poço, in the state of Pará. The vertical distribution of bryophytes was evaluated in 15 host trees within the primary forest. We identified a total of 99 bryophyte species: 33 mosses and 66 liverworts. The dominant family was Lejeuneaceae, with 56 species. Most of the species (n = 60) had a neotropical distribution, and 3 species were endemic to Brazil. Cololejeunea minutissima var. myriocarpa (Nees & Mont.) R.M.Schust., Pycnolejeunea papillosa X.-L. He, Radula mammosa Spruce and Verdoornianthus marsupiifolius (Spruce) Gradst. represent new records for the state of Pará. In the successional forests evaluated, we identified 78 species, most of which (n = 38) occurred in primary forest. On the host tree trunks evaluated in the primary forest, we observed 31 species occurring at heights ranging from 2 m to 20 m. Despite the fact that secondary forests account for such a large proportion of the forested areas in Capitão Poço, we found that the bryoflora was relatively rich, comprising 31% of the species recorded for the state. The fact that 40% of the species recorded occurred exclusively in the secondary forests and the fact that 45.5% of the species recorded in primary forest occurred within the 2-20 m height range show the importance of studies focusing on bryophytes in secondary forests and in the upper strata of host trees in primary forests.
Este artículo analiza el uso del trabajo en equipo entre los docentes como estrategia de cambio en la educación pública básica. Se considera que las escuelas no son el último peldaño para tomar decisiones, pues la creación de espacios para grupos de trabajo, dentro de las escuelas, permitiría innovaciones a partir de la complementariedad de conocimientos y habilidades entre docentes y directivos. El artículo considera las actitudes de los docentes frente a la actividad magisterial, en particular frente a los alumnos con rezago, y se discuten los problemas en la formación de grupos de trabajo, como la distribución de beneficios del trabajo conjunto y las conductas de polizón. Para ello, se propone el diseño de políticas públicas que fomenten la colaboración con base en incentivos no pecuniarios apoyados en factores como: la motivación profesional, la reducción de costos del esfuerzo de docencia y la posibilidad de compartir los riesgos de éxito o fracaso en la práctica de enseñanza.
Chlamydophila psittaci (Bacteria kingdom, Chlamydiae phylum, Chlamydiae class, Chlamydiales order, Chlamydiaceae family) is part of the genus Chlamydophila, where Cp. abortus, Cp. caviae, Cp. felis, Cp. pecorum and Cp. pneumoniae are the other five species of bacteria [1]. Avian chlamydiosis induced by this Gram-negative obligate intracellular bacteria [2] is traditionally known as ornithosis or psittacosis [3-5]. It is an infectious disease capable of infecting domestic and wild birds [6,7], being the Psittacidae family where most occurrences are reported [8]. Chlamydophila psittaci infects primarily birds [9], but mammals, including humans, are also susceptible of infection [10-11]. In fact, zoonotic status of this organism is largely described and emphasizes the scientific reports worldwide [12-15]. Chlamydophila psittaci can be found in bird feathers, excrements and blood, whether or not these animals are showing clinical signs of disease [16,17]. Psittacosis can be transmitted by vertical and horizontal via [2]. The agent is excreted on faeces and ingested from the food or inhaled via aerosols [13]. At the lungs of newly infected animals, the organism gets an infecting status becoming capable to replicate and causing clinical signs of disease [18,19]. There are three morphologically distinct forms of Chlamydophila: • The elementary body, which is small, spherical, of about 0.2-0.3 mm in diameter; • The reticular body, wider, of about 0.5-2.0 mm, which is able to replicate by binary division; • And the intermediate body, with 0.3-2.0 mm in diameter, seen in infected host cells [18,20].
Aim: The aim of this study was to design, develop and compare ultrasound tips with different angulations on time required for cast post removal. Materials and methods:To test and compare the ultrasonic tips developed, 36 metal patterns were fabricated from tin bars, on a mechanical precision lathe. Each metal pattern simulated an endodontically treated tooth, without coronal remaining, prepared to receive a cast post with 10 mm long. The cast posts were cemented with zinc phosphate cement. The metal patterns with their respective intraradicular posts cemented were stored at 37ºC, at relative humidity 100%, for a period of 48 hours. After this period, the specimens were randomly divided into three groups, and each group was submitted to the action of one of the ultrasonic tips (n = 12): G1-tip with 30º angulation; G2-tip with 45º angulation and G3-tip without angulation (straight tip). Each ultrasonic tip was used on the surfaces of the cast posts (mesial, distal, buccal, lingual and incisal) for 5 seconds, at maximum power, until the cast post removal using an ultrasound device (Jet Sonic, Satelec System, Gnatus, Ribeirão Preto, SP, Brazil). The time required for cast posts removal was recorded and the data statistically analyzed by the ANOVA and Tukey tests (p < 0.05). Results:The means of time evaluated for cast posts removal were G1: 59.25s; G2: 119.0s and G3: 48.4s. Group 2 presented the highest mean value in seconds, differing statistically from G1 and G3. No significant differences were observed between G1 and G3. Conclusion:It may be concluded that the ultrasonic tip angu lation had a direct influence on the time required for cast posts removal by ultrasound. When the different ultrasonic tips were compared, the 30° angulation and the straight tips required a shorter ultrasonic vibration time. All cast posts luted with zinc phosphate were successfully removed in a relatively short time by the different ultrasonic tips analyzed.
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