1,278 research outputs found

    Yield And Nutritive Value Of The Silage Of Corn Intercropped With Tropical Perennial Grasses

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    The objective of this work was to compare the yield and nutritive value of the silage of corn intercropped with palisade grass (Urochloa brizantha 'Marandu') or guinea grass (Megathyrsus maximus 'TanzĂąnia') with those of the silage of monocropped corn, as well as to evaluate the pasture established in the intercropping systems during two growing seasons (2010-2011 and 2011-2012), in low-altitude Brazilian Cerrado. The treatments consisted of three cropping systems: monocropped corn, corn intercropped with palisade grass, and corn intercropped with guinea grass, with four replicates. Intercropping decreased corn forage dry matter yield for silage; however, due to the addition of grass, total dry matter yield (corn + grass) was similar between treatments. Intercropping also did not negatively affect corn production components and morphological characteristics. The cropping systems provided silages with good nutritive values, and the inclusion of tropical forages increased the silage fiber contents. Intercropping corn with tropical perennial grasses is a viable option for producing large quantities of silage with good nutritive value. The forage yield (silage + pasture) of these intercropping systems is similar to that of monocropped corn in tropical regions and has the advantage of providing a pasture in the off-season.521637

    Structural and optical studies of FeSb2 under high pressure

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    Nanostructured orthorhombic FeSb2 and an amorphous phase were formed by mechanical alloying starting from a mixture of high purity elemental Fe and Sb powders. The effects of high pressures on structural and optical properties were studied using X-ray diffraction (XRD) and Raman spectroscopy (RS). XRD patterns showed the presence of the orthorhombic FeSb2 phase up to the maximum pressure applied (28.2 GPa). The XRD patterns showed also an increase in the amount of the amorphous phase with increasing pressure up to 23.3 GPa. At 14.3 GPa, together with the former phases, a new phase was observed and indexed to a tetragonal FeSb2 phase, but its volume fraction is small at least up to 23.3 GPa. For the orthorhombic FeSb2 phase, the pressure dependence of the volume fitted to a Birch-Murnaghan equation of state gave a bulk modulus = 74.2 +- 3.0 GPa and its pressure derivative = 7.5 +- 0.6. RS measurements were performed from atmospheric pressure up to 45.2 GPa. For the orthorhombic FeSb2 phase, the Raman active mode was observed up to the maximum pressure applied, while the mode disappeared at 16.6 GPa. For pressures higher than 21 GPa, the Raman active mode of a tetragonal FeSb2 phase was observed, confirming ab initio calculations reported in the literature.Comment: 31 pages, 11 figures and 2 tables. Already submitted for publicatio

    The Use of Autoscopy From the Epistemological Perspective of Action Research for Self-Analysis and Reflection of Teacher Practice

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    The video recording of lessons allows the analysis results to provide data about the teaching practice. Analyzing the pedagogical practice itself allows the teacher an exercise of self-reflection, as they become aware of their behavior in the classroom, leading to the revitalization of their teaching model. This study aims to present the use of autoscopy as a stimulus to reflection, to a new understanding of the pedagogical practice of teachers, in an action research. This is a case study, with a qualitative and descriptive approach, performed with a new nursing teacher. The data were initially collected through a semistructured biographical interview and subsequent video recording of the classes, characterizing nonparticipant observations. The application of autoscopy followed the proposal of action research, with its phases: exploratory phase, in-depth research, action phase, and evaluation phase. The autoscopy was a useful strategy to stimulate teacher reflection because during the projection of the sketches selected for the video of the autoscopy session, the teacher can see himself or herself in action and self-analyze and discuss the selected pedagogical moments, stimulating reflection and generating a new understanding about his or her teaching practice. In this way, the use of autoscopy under the epistemological perspective of action research stimulates the self-analysis and reflection of the teaching practice

    Coercivity behavior in Gd(Co1−xCux)5 system as function of the microstructureevolution

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    AbstractMagnetic measurements, X-ray diffraction and scanning electron microscopy (SEM) experiments were carried out in the as-cast Gd(Co1−xCux)5 samples with different Co/Cu content. Already in the as cast state, this system shows high coercive field for x=0.3 and a magnetization driven by nucleation of reversal domain. SEM micrograph and microanalysis show possible spinodal decomposition in the as-cast state, hence regions with different Co/Cu-content are observed, while the Gd-content almost does not change. High resolution X-ray diffraction patterns show a main CaCu5-type structure with traces of a secondary phase and distorted peak profiles as function of the Cu content. The evolution of the microstructure is discussed in relation with the Cu incorporation into the CaCu5-type structure. The Cu addition avoids the formation of the 2:7 phase within the 1:5 matrix, favoring the formation of a more homogeneous Gd(Co,Cu)5 phase. The relation between the observed microstructure and the magnetic behavior is also discussed

    Regional differences of testicular artery blood flow in post pubertal and pre-pubertal dogs

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    Background Measurement of testicular artery blood flow is used in several species to evaluate reproductive function and testicular and scrotal pathology. In dogs there are inconsistent reports about normal flow in post-pubertal dogs and no information concerning pre-pubertal dogs. The aim of this study was to describe regional differences in testicular artery blood flow in clinically normal post-pubertal and pre-pubertal dogs with no history of reproductive tract disease. Results The post-pubertal dogs produced normal ejaculates throughout the study. In all dogs the three different regions of the artery were imaged and monophasic flow with an obvious systolic peak and flow throughout diastole was observed on every occasion. The highest peak systolic velocity (PSV) and end diastolic velocity (EDV) were measured within the distal supra-testicular artery and marginal artery whilst the lowest PSV and EDV were measured within the intra-testicular arteries. Flow measurements were not different between left and right testes and were consistent between dogs on different examination days. Calculated resistance index (RI) and pulsatility index (PI) were lowest in the intra-testicular arteries. The pre-pubertal dogs had significantly smaller testes than the post-pubertal dogs (p < 0.05) and were unable to ejaculate during the study. The three different artery regions were imaged at every examination time point, and flow profiles had a similar appearance to those of the post-pubertal dogs. PSV, EDV, RI and PI showed a similar trend to the post-pubertal dogs in that values were lowest in the intra-testicular arteries. Notably, values of PSV, EDV, RI and PI were significantly lower (p < 0.05) in pre-pubertal dogs compared with post-pubertal dogs. Conclusions This study demonstrated important regional and pubertal differences in testicular artery blood flow of dogs, and form the basis for establishing baseline reference values that may be employed for the purposes of clinical diagnosis

    Root dentinal microcracks: a post-extraction experimental phenomenon?

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    Aim To investigate the prevalence, location and pattern of pre‐existing microcracks in non‐endodontically treated teeth from fresh cadavers. Micro‐computed tomography (micro‐CT) technology was used as the analytical tool enabling full screening of the root dentine with the teeth retained in their original alveolar socket. Methodology As a pilot study and to validate the present method, a series of 4 high‐resolution scans were performed on one bone‐block specimen with teeth collected post‐mortem: (i) entire bone‐block including the teeth, (ii) second molar tooth extracted atraumatically from the bone‐block, (iii) extracted tooth dehydrated to induce dentinal defects and (iv) entire bone‐block following reinsertion of the extracted tooth into its matching alveolar socket. In the main study, forty‐two dentoalveolar maxillary and mandibular bone‐blocks each containing 3–5 adjacent teeth (a total of 178 teeth) were collected post‐mortem and scanned in a micro‐CT device. All cross‐section images of the 178 teeth (n = 65 530) were screened from the cementoenamel junction to the apex to identify the presence of dentinal defects. Results In the pilot study, the microcracks observable when the dehydrated tooth was outside the bone‐block remained detectable when the entire bone‐block plus reinserted tooth was scanned. This means that the screening process revealed the presence of the same microcracks in both experimental situations (the tooth outside and inside the maxillary bone‐block). From a total of 178 teeth in the bone‐blocks removed from cadavers, 65 530 cross‐sectional images were analysed and no dentinal microcracks were detected. Conclusions This in situ cadaveric model revealed the lack of pre‐existing dentinal microcracks in non‐endodontically treated teeth. Thus, the finding of dentinal microcracks observed in previous cross‐sectional images of stored extracted teeth is unsound and not valid. It should be assumed that microcracks observed in stored extracted teeth subjected to root canal procedures are a result of the extraction process and/or the post‐extraction storage conditions. Therefore, as a consequence, the presence of such dentinal microcracks in stored extracted teeth – observable in cross‐sectional images of the roots – should be referred to as experimental dentinal microcracks
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