920 resultados para Science Ability testing
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Negative dimensional integration method (NDIM) is a technique to deal with D-dimensional Feynman loop integrals. Since most of the physical quantities in perturbative Quantum Field Theory (pQFT) require the ability of solving them, the quicker and easier the method to evaluate them the better. The NDIM is a novel and promising technique, ipso facto requiring that we put it to test in different contexts and situations and compare the results it yields with those that we already know by other well-established methods. It is in this perspective that we consider here the calculation of an on-shell two-loop three point function in a massless theory. Surprisingly this approach provides twelve non-trivial results in terms of double power series. More astonishing than this is the fact that we can show these twelve solutions to be different representations for the same well-known single result obtained via other methods. It really comes to us as a surprise that the solution for the particular integral we are dealing with is twelvefold degenerate.
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We derive bounds on Higgs and gauge-boson anomalous interactions using the CDF data for the process pp̄ → γγγ + X. We use a linearly realized SU L(2) X U Y(1) invariant effective Lagrangian to describe the bosonic sector of the Standard Model, keeping the fermionic couplings unchanged. All dimension-six operators that lead to anomalous Higgs interactions involving γ and Z are considered. We also show the sensitivity that can be achieved for these couplings at Fermilab Tevatron upgrades. © 1998 Published by Elsevier Science B.V. All rights reserved.
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Purpose: The effect of water immersion on the shear bond strength (SBS) between 1 heat-polymerizing acrylic resin (Lucitone 550-L) and 4 autopolymerizing reline resins (Kooliner-K, New Truliner-N, Tokuso Rebase Fast-T, Ufi Gel Hard-U) was investigated. Specimens relined with resin L were also evaluated. Materials and Methods: One hundred sixty cylinders (20 × 20 mm) of L denture base resin were processed, and the reline resins were packed on the prepared bonding surfaces using a split-mold (3.5 × 5.0 mm). Shear tests (0.5 mm/min) were performed on the specimens (n = 8) after polymerization (control), and after immersion in water at 37°C for 7, 90, and 180 days. All fractured surfaces were examined by scanning electron microscopy (SEM) to calculate the percentage of cohesive fracture (PCF). Shear data were analyzed with 2-way ANOVA and Tukey's test; Kruskall-Wallis test was used to analyze PCF data (α = 0.05). Results: After 90 days water immersion, an increase in the mean SBS was observed for U (11.13 to 16.53 MPa; p < 0.001) and T (9.08 to 13.24 MPa, p = 0.035), whereas resin L showed a decrease (21.74 MPa to 14.96 MPa; p < 0.001). The SBS of resins K (8.44 MPa) and N (7.98 MPa) remained unaffected. The mean PCF was lower than 32.6% for K, N, and T, and higher than 65.6% for U and L. Conclusions: Long-term water immersion did not adversely affect the bond of materials K, N, T, and U and decreased the values of resin L. Materials L and U failed cohesively, and K, N, and T failed adhesively. © 2007 by The American College of Prosthodontists.
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Newly available materials for retrograde obturation should have their sealing properties evaluated. The goal of this study was to evaluate the sealing ability of Endo CPM sealer, an MTA-based endodontic cement. Single-rooted extracted human teeth were endodontically treated. After apical sectioning, retrograde cavities were prepared. Teeth were divided into five experimental groups (n=12), in which the following materials were used: Sealer 26 (S26), white Mineral Trioxide Aggregate (MTA), Endo CPM Sealer (CPM1), Endo CPM Sealer in thicker consistency (CPM 2), and zinc oxide and eugenol cement (ZOE), and two control groups (n=3). After retrograde obturation, the teeth were immersed in 0.2% rhodamine B dye for 48 hours in a vacuum chamber Marginal leakage data were subjected to ANOVA and Tukey tests at 5% significance level. S26 presented greater sealing ability (p<0.05) than ZOE, MTA, CPM1, and CPM2, all of which had similar results (p>0.05). We concluded that Sealer 26 has the greatest sealing ability. Endo CPM Sealer, with sealing ability similar to MTA, could be used as a retrograde obturation material.
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Includes bibliography
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In this paper, we report on a field experiment being carried out in a Typic Eutrorthox. The experiment was initiated in the 1997-98 agricultural season as a randomized block design with four treatments (0, 5, 10, and 20 t ha -1) of sewage sludge and five replicates. Compound soil samples were obtained from 20 subsamples collected at depths of 0-0.1 and 0.1-0.2 m. Cu, Fe, Mn, and Zn concentrations were extracted with DTPA pH 7.3; 0.1 mol L -1 HCl, Mehlich-I, Mehlich-III, and 0.01 mol L-1 CaCl 2. Metal concentrations were determined via atomic absorption spectrometry. Diagnostic leaves and the whole above-ground portion of plants were collected to determine Cu, Fe, Mn, and Zn concentrations extracted by nitric-perchloric digestion and later determined via atomic absorption spectrometry. Sewage sludge application caused increases in the concentrations of soil Cu, Fe, and Mn in samples taken from the 0-0.1 m depth evaluated by the extractants Mehlich-I, Mehlich-III, 0.01 mol L-1 HCl and DTPA pH 7.3. None of the extractants provided efficient estimates of changes in Mn concentrations. The acid extractants extracted more Cu, Fe, Mn, and Zn than the saline and chelating solutions. The highest concentrations of Cu, Fe, and Zn were obtained with Mehlich-III, while the highest concentrations of Mn were obtained with HCl. We did not observe a correlation between the extractants and the concentrations of elements in the diagnostic leaves nor in the tissues of the whole maize plant (Zea mays L.). © 2013 Springer Science+Business Media Dordrecht.
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Two studies were conducted to understand sperm cryosensitivity in an endangered equid, the Przewalski's horse (Equus ferns przewalski), while testing the cryoprotectant ability of formamides. The first assessed the toxicity of permeating cryoprotectants (glycerol, methylformamide IMF] and dimethylformamide [DMF]) to Przewalski's horse spermatozoa during liquid storage at 4 C. The second examined the comparative influence of three diluents (with or without formamides) on cryosurvival of sperm from the Przewalski's versus domestic horse. When Przewalski's horse spermatozoa were incubated at 4 C in INRA 96 with differing concentrations of glycerol, MF or DMF or a combination of these amides, cells tolerated all but the highest concentration (10% v/v) of MF alone or in combination with DMF, both of which decreased (P < 0.05) motility traits. There was no effect of cryoprotectants on sperm acrosomal integrity. In the cryosurvival study, average sperm motility and proportion of cells with intact acrosomes in fresh ejaculates were similar (P> 0.05) between the Przewalski's (67%, 84%, respectively) and domestic (66%, 76%) horse donors. Sperm from both species were diluted in lactose-EDTA-glycerol (EQ), Botu-Crio (BOTU; a proprietary product containing glycerol and MF) or SM (INRA 96 plus 2% [v/v] egg yolk and 2.5% [v/v] MF and DMF) and then frozen over liquid nitrogen vapor. After thawing, the highest values recovered for total and progressive sperm motility, acrosomal integrity and mitochondria] membrane potential were 42.4%, 21.8%, 88.7% and 25.4 CN (CN = mean JC-1 fluorescence intensity/cell on a channel number scale), respectively, in the Przewalski's and 49.3%, 24.6%, 88.9% and 25.8 CN, respectively, in the domestic horse. Although sperm progressive motility and acrosome integrity did not differ (P> 0.05) among treatments across species, mitochondrial membrane potential was higher (P< 0.05) in both species using EQ compared to BOTU or SM media. Additionally, Przewalski's stallion sperm expressed higher (P < 0.05) post-thaw total motility in BOTU and SM compared to EQ whereas there were no differences among freezing diluents in the domestic horse. In summary, Przewalski's stallion sperm benefit from exposure to either MF or DMF as an alternative cryoprotectant to glycerol. Overt sperm quality appears similar between the Przewalski's and domestic horse, although the total motility of cells from the former appears more sensitive to certain freezing diluents. Nonetheless, post-thaw motility and acrosomal integrity values for Przewalski's horse spermatozoa mimic findings in the domestic horse in the presence of INRA 96 supplemented with 2% (v/v) egg yolk and a combined 2.5% concentration of MF and DMF. Published by Elsevier Inc.
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Several cognitive tests have been developed to evaluate specific aspects of human and animal learning and memory. These tests have been used for early detection of cognitive deficits and to monitor the treatment of dogs with cognitive impairment. Thus, this article evaluated the feasibility of cognitive tests for use in canine neurology clinical routines and the suitability of the different tests to accomplish this aim. Fifteen healthy adult dogs were used for the cognitive tests of reward approach learning, object approach learning, object discrimination learning, reversal learning, delayed non-matched to position, and delayed non-matched to sample to assess different aspects of memory. No difference was observed between tests of delayed non-matched to position (3.13 +/- 2.23 days) and delayed non-matched to sample (3.20 +/- 2.40 days) (P = 0.944). However, dogs had greater difficulty in reversal learning (8.47 +/- 2.61 days) than in object discrimination learning (4.60 +/- 1.64 days) (P <= 0.001). Based on the tests performed, the delayed non-matched to position test may be performed in clinical routine if the owner and the veterinarian have time available, because this test is sensitive to evaluate dogs with cognitive impairments, but requires approximately 10 days of training. Thus, elderly dogs are excellent experimental models to study pathological aging based on their similarities with some human brain diseases, such as Alzheimer disease. (C) 2014 Elsevier Inc. All rights reserved.
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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This article presents some results of a study investigating the use of the simulator VLAB, developed by Carnegie Mellon University, to increase the capacity of graduate students in Chemistry in the preparation of experimental procedures. The activity was conducted in two stages, first the students were asked a manuscript describing in detail the procedure and equipment used in the technique of dissolution and delivering it to the teacher. Later in the computer lab, each student performed the same procedure using the simulator. The activity has been proposed to determine if there could be accuracy gains of the description of the process when performed by the simulator. One of the main positive aspects obtained using the simulator students was the recognition of error, important in that the great majority recognized omitted or confused any process step. This reflection showed the students that in addition to testing a procedure using the simulator facilitates the organization of thought and helps arrange it logically. With the use of simulators, students are encouraged to take risks, to explore, to experience a new way, and a real lab usually offers much less room for risk, exploitation and failure.
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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This action research project describes a research project designed and implemented specifically with an emphasis on the instruction of mathematical vocabulary. The targeted population was my second period classroom of sixth grade students. This group of seventeen students represented diverse socioeconomic backgrounds and abilities. The school is located in a community of a population of approximately 5,000 people in the Midwest. My research investigation focused on the use of specific methods of vocabulary instruction and students’ use of precise mathematical vocabulary in writing and speaking. I wanted to see what effects these strategies would have on student performance. My research suggested that students who struggle with retention of mathematical knowledge have inadequate language skills. My research also revealed that students who have a sound knowledge of vocabulary and are engaged in the specific use of content language performed more successfully. Final analysis indicated that students believed the use of specific mathematical language helped them to be more successful and they made moderate progress in their performance on assessments.
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In this action research study of my fifth grade high-ability mathematics class, I investigated student attitudes of mathematics and their confidence in mathematics. Student achievement was compared to two different confidence scales to identify a relationship between confidence and achievement. Six boys and eleven girls gave their consent to the study. I discovered there seems to be a connection between confidence and achievement and that boys are generally more confident than girls. Most students liked math and were comfortable sharing answers and methods of solving problems with other students. As a result of this study I plan to use my survey and interview questions at the beginning of the school year with my new class in order to assess their attitudes and confidence in math. I can use this information to identify potential struggles and better plan for student instruction.
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Software product line (SPL) engineering offers several advantages in the development of families of software products such as reduced costs, high quality and a short time to market. A software product line is a set of software intensive systems, each of which shares a common core set of functionalities, but also differs from the other products through customization tailored to fit the needs of individual groups of customers. The differences between products within the family are well-understood and organized into a feature model that represents the variability of the SPL. Products can then be built by generating and composing features described in the feature model. Testing of software product lines has become a bottleneck in the SPL development lifecycle, since many of the techniques used in their testing have been borrowed from traditional software testing and do not directly take advantage of the similarities between products. This limits the overall gains that can be achieved in SPL engineering. Recent work proposed by both industry and the research community for improving SPL testing has begun to consider this problem, but there is still a need for better testing techniques that are tailored to SPL development. In this thesis, I make two primary contributions to software product line testing. First I propose a new definition for testability of SPLs that is based on the ability to re-use test cases between products without a loss of fault detection effectiveness. I build on this idea to identify elements of the feature model that contribute positively and/or negatively towards SPL testability. Second, I provide a graph based testing approach called the FIG Basis Path method that selects products and features for testing based on a feature dependency graph. This method should increase our ability to re-use results of test cases across successive products in the family and reduce testing effort. I report the results of a case study involving several non-trivial SPLs and show that for these objects, the FIG Basis Path method is as effective as testing all products, but requires us to test no more than 24% of the products in the SPL.