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Designing and Implementing a Limit Diagnostic Tool
Get PDFAbstract: The purpose of this study is to create and utilize a tool that evaluates students' comprehension of the logical structure and implications of the formal definition of limit. This study continues the trajectory of recent limit research involving classroom-based interventions that reveal student metaphors and conception
Association of Researchers in Construction Management
No full textOrganizations increasingly bridge capacity gaps when providing goods or services through collaboration. Forms of collaboration include partnerships, alliances and joint ventures. Infrastructure projects in Hong Kong often require clusters of resources, skills and capabilities that are difficult to obtain for any single organization to source using in-house resources. Large infrastructure providers have sought to overcome this problem by forming joint ventures (JVs) and other forms of relationships to co-operatively undertake these projects. One motivation for establishing these relationships is to spread financial and other risk. Another motivation is to capture learning so that this hidden and intangible asset may applied later to improve their competitive advantage. Results from a pilot study investigating the nature of the JV relationship in Hong Kong are reported upon in this paper. This research focused upon organizational learning intentions of interviewed JV representatives. It explored why learning from JV partners was deemed important by respondents and intended strategies that facilitate this learning. Results indicate that respondents have a strong strategic desire for learning from partners in collaborative relations that deliver these projects
Original Article
No full textHow to cite this article Objective: analyze the concentration of polycyclic aromatic hydrocarbons in electrocautery smoke in operating rooms and the use of personal protective equipment by the intraoperative team when exposed to hydrocarbons. Method: exploratory and cross-sectional field research conducted in a surgery center. Gases were collected by a vacuum suction pump from a sample of 50 abdominal surgeries in which an electrocautery was used. A form was applied to identify the use of personal protective equipment. Gases were analyzed using chromatography. Descriptive statistics and Spearman's test were used to treat data. Results: there were 17 (34%) cholecystectomies with an average duration of 136 minutes, while the average time of electrocautery usage was 3.6 minutes. Airborne hydrocarbons were detected in operating rooms in 100% of the surgeries. Naphthalene was detected in 48 (96.0%) surgeries and phenanthrene in 49 (98.0%). The average concentration of these compounds was 0.0061 mg/m3 and a strong correlation (0.761) was found between them. The intraoperative teams did not use respirator masks such as the N95. Conclusion: electrocautery smoke produces gases that are harmful to the health of the intraoperative team, which is a concern considering the low adherence to the use of personal protective equipment
Anti-sway Control Input for Overhead Traveling Crane Based on Natural Period
No full textAbstract For safe and efficient work of handling task for heavy load by overhead traveling crane, sway of the suspended load should be avoided. presented. This method can be easily applied for an anti-sway control of the crane system when typical servo controller is used. The idea is also applied for the case of changing rope length of the overhead traveling crane system
Agronomy Maringá, v
No full textABSTRACT. The aim of this study was to evaluate the genetic dissimilarity among wild and domesticated species of Manihot for resistance to cassava green mite during the insect life cycle. Nine accessions of wild Manihot species, M. esculenta ssp. flabellifolia, M. esculenta ssp. peruviana, and M. carthaginensis ssp. glaziovii, and two clones of M. esculenta (Cigana Preta and Sacaí) were evaluated under laboratory conditions at 25 ± 1°C, 70 ± 10% RH, and a 12-h photophase. Daily observations during the mite life cycle stages (larva-adult) were recorded. The data were subjected to an analysis of variance, a Scott-Knott test (5%), and Singh criterion, cluster, and principal component analyses. The larval-adult period ranged from 5.53 to 7.01 days: the longest period was observed on an M. glaziovii accession (GLA-19-DF) and the shortest on an M. flabellifolia accession (FLA-025V). The UPGMA method allowed the division of the genotypes into six groups, with the greatest distance between the FLA-025V and GLA-19-DF accessions. The first two main components explained 77.50% of the total accumulated variation. The association of the longest cycle duration of M. tanajoa with the lowest larval-adult viability suggests that GLA-19-DF is less favorable to mite development compared to the other accessions. Significant variability among the genotypes was observed. o C, 70±10% de UR e 12 h de fotofase. Foram realizadas observações diárias sobre a duração das fases do ciclo biológico (larva-adulto). Os dados submetidos à análise de variância, teste Scott-Knott (5%), critério de Singh, análise multivariada de agrupamento e de componentes principais. O período larva-adulto variou de 5,53 a 7,01 dias. O maior período foi verificado no acesso de M. glaziovii , e o menor no acesso de M. flabellifolia (FLA-025V). O método de UPGMA, propiciou a divisão dos genótipos em seis grupos. A maior distância foi entre o acesso FLA-025V e GLA-19-DF. As duas primeiras componentes principais explicaram 77,50% da variação total acumulada. A maior duração do ciclo de M. tanajoa associado a menor viabilidade larvaadulto sugere que o acesso GLA-19-DF é menos favorável ao desenvolvimento do ácaro em relação aos demais e verificou-se variabilidade genética entre os genótipos avaliados. Palavras chave: biologia, mandioca, estresse biótico, ácaro verde
Effects of Computer-Based Cooperative Learning Method on Students' Attitudes Towards English Grammar in Secondary Schools in Njoro Sub- County, Kenya
No full textABSTRACT This study was conducted to find out the effects of Computer-Based Cooperativ
Revista Brasileira de Parasitologia Veterinária Factors associated with parasite aggregation levels in fishes from Brazil Fatores associados aos níveis de agregação parasitária em peixes do Brasil
No full textAbstract The degree of parasite aggregation is determined by a number of factors that are not well understood. In total, 3,746 fish from 73 species and their parasites were analyzed to determine associations between the degree of aggregation by taxon and specific characteristics of the fish. A multiple linear regression (95% confidence interval -CI) was used to show that in most taxa, the degree of parasite aggregation was significantly higher in freshwater fish and schooling fish but varied according to taxon in relation to gender, habitat and feeding habits. Parasite aggregations were also significantly increased in fish with a large number of parasitic larvae and greater body length in all evaluated taxa. Because the coefficients of determination of the models were lower than 60% for all taxa, other factors may be involved in parasite aggregation. Conversely, marked significance was observed for the tested variables in relation to taxon dependence, which indicates that additional studies should be performed for these factors using comprehensive databases with larger samples per parasite species. Keywords: Epidemiology, parasite ecology, multiple regression analysis. Resumo O nível de agregação parasitária é determinado por um conjunto de fatores não muito bem elucidados. Foram analisados 3.746 peixes pertencentes a 73 espécies e seus respectivos parasitos, com o objetivo de verificar a associação entre o nível de agregação por táxon e algumas características dos peixes. Por meio da técnica de regressão linear múltipla (IC 95%), observou-se que o nível de agregação de parasitos foi significativamente maior em peixes dulcícolas e formadores de cardume, na maioria dos táxons, mas variou conforme o táxon em relação ao sexo, o hábitat e o hábito alimentar. A agregação parasitária também aumentou significativamente em peixes com maior proporção de larvas parasitas e com maior comprimento do corpo em todos os táxons avaliados. Tendo em vista que os coeficientes de determinação dos modelos para todos os táxons foram inferiores a 60%, outros fatores podem estar envolvidos na agregação de parasitos. Por outro lado, as variáveis testadas assumem importância diferenciada na dependência do táxon, sinalizando para a necessidade de se continuar pesquisando esses fatores em bancos de dados mais abrangentes e com amostras maiores por espécies de parasitos. Palavras-chave: Epidemiologia, ecologia parasitária, análise de regressão múltipla
Estrogens, Enzyme Variants, and Breast Cancer: A Risk Model
No full textAbstract Oxidative metabolites of estrogens have been implicated in the development of breast cancer, yet relatively little is known about the metabolism of estrogens in the normal breast. We developed a mathematical model of mammary estrogen metabolism based on the conversion of 17B-estradiol (E 2 ) by the enzymes cytochrome P450 (CYP) 1A1 and CYP1B1, catechol-O-methyltransferase (COMT), and glutathione S-transferase P1 into eight metabolites [i.e., two catechol estrogens, 2-hydroxyestradiol (2-OHE 2 ) and 4-hydroxyestradiol (4-OHE 2 ); three methoxyestrogens, 2-methoxyestradiol, 2-hydroxy-3-methoxyestradiol, and 4-methoxyestradiol; and three glutathione (SG)-estrogen conjugates, 2-OHE 2 -1-SG, 2-OHE 2 -4-SG, and 4-OHE 2 -2-SG]. When used with experimentally determined rate constants with purified enzymes, the model provides for a kinetic analysis of the entire metabolic pathway. The predicted concentration of each metabolite during a 30-minute reaction agreed well with the experimentally derived results. The model also enables simulation for the transient quinones, E 2 -2,3-quinone (E 2 -2,3-Q) and E 2 -3,4-quinone (E 2 -3,4-Q), which are not amenable to direct quantitation. Using experimentally derived rate constants for genetic variants of CYP1A1, CYP1B1, and COMT, we used the model to simulate the kinetic effect of enzyme polymorphisms on the pathway and identified those haplotypes generating the largest amounts of catechols and quinones. Application of the model to a breast cancer case-control population identified a subset of women with an increased risk of breast cancer based on their enzyme haplotypes and consequent E 2 -3,4-Q production. This in silico model integrates both kinetic and genomic data to yield a comprehensive view of estrogen metabolomics in the breast. The model offers the opportunity to combine metabolic, genetic, and lifetime exposure data in assessing estrogens as a breast cancer risk factor. (Cancer Epidemiol Biomarkers Prev 2006;15(9):1620 -9
Perceptions and uptake of health insurance for maternal care in rural Kenya: a cross sectional study
No full textAbstract Introduction: In Kenya, maternal and child health accounts for a large proportion of the expenditures made towards healthcare. It is estimate
