924 resultados para 280401 Analysis of Algorithms and Complexity


Relevância:

100.00% 100.00%

Publicador:

Resumo:

This study examined university students' writing skills as perceived by university students and their English instructors. The goal of the study was to provide English instructors with objective, quantified information about writing perceptions from both the students' and instructors' viewpoints. ^ A survey instrument was developed based on a survey instrument created by Newkirk, Cameron, and Selfe (1977) to identify instructors' perceived knowledge of student writing skills. The present study used a descriptive statistical design. It examined five writing skill areas: attitude, content, grammar and mechanics, literary considerations, and the writing process through a questionnaire completed by a convenience sample of summer and fall admitted freshmen who were enrolled in Essay Writing and Freshman Composition courses and English Department instructors at a large South Florida public university. ^ The study consisted of five phases. The first phase was modifying of the Newkirk, Cameron, and Selfe (1977) questionnaire. Two versions of the revised survey were developed - one for instructors and one for students. The second phase was pilot testing the questionnaire for evaluation of administration and scoring. The third phase was administering the questionnaire to 1,280 students and 48 instructors. The fourth phase was analyzing the data. The study found a significant difference in the perceptions of students and instructors in all areas of writing skills examined by the survey. Responses to 29 of 30 questions showed that students felt they had better attitudes toward writing and better writing skills than instructors thought. ^ The final phase was developing recommendations for practice. Based on findings and theory and empirical evidence drawn from the fields of adult education and composition research, learner-centered, self-directed curriculum guidelines are offered. ^ By objectively quantifying student and instructor perceptions of students' writing skills, this study contributes to a growing body of literature that: (a) encourages instructors to acknowledge the perception disparities between instructors and students; (b) gives instructors a better understanding of how to communicate with students; and (c) recommends the development of new curriculum, placement tests, and courses that meet the needs of students and enables English instructors to provide meaningful instruction. ^

Relevância:

100.00% 100.00%

Publicador:

Resumo:

During the remediation of burial grounds at the US Department of Energy's (DOE's) Hanford Site in Washington State, the dispersion of contaminated soil particles and dust is an issue that is faced by site workers on a daily basis. This contamination problem is even more of a concern when one takes into account the semi-arid characteristics of the region where the site is located. To mitigate this problem, workers at the site use a variety of engineered methods to minimize the dispersion of contaminated soil and dust (i.e. use of water and/or suppression agents that stabilizes the soil prior to soil excavation, segregation, and removal activities). A primary contributor to the dispersion of contaminated soil and dust is wind soil erosion. The erosion process occurs when the wind speed exceeds a certain threshold value which depends on a number of factors including wind force loading, particle size, surface soil moisture, and the geometry of the soil. Thus under these circumstances, the mobility of contaminated soil and generation and dispersion of particulate matter are significantly influenced by these parameters. This dependence of soil and dust movement on threshold shear velocity, fixative dilution and/or application rates, soil moisture content, and soil geometry were studied for Hanford's sandy soil through a series of wind tunnel experiments, laboratory experiments and theoretical analysis. In addition, the behavior of plutonium (Pu) powder contamination in the soil was studied by introducing a Pu simulant (cerium oxide). The results showed that soil dispersion and PM10 concentrations decreased with increasing soil moisture. Also, it was shown that the mobility of the soil was affected by increasing wind velocity. It was demonstrated that the use of fixative products greatly decreased the amount of soil and PM10 concentrations when exposed to varying wind conditions. In addition, it was shown that geometry of the soil sample affected the velocity profile and calculation of roughness surface coefficient when comparing round and flat soil samples. Finally, threshold shear velocities were calculated for soil with flat surface and their dependency on surface soil moisture was demonstrated. A theoretical framework was developed to explain these dependencies.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Today, over 15,000 Ion Mobility Spectrometry (IMS) analyzers are employed at worldwide security checkpoints to detect explosives and illicit drugs. Current portal IMS instruments and other electronic nose technologies detect explosives and drugs by analyzing samples containing the headspace air and loose particles residing on a surface. Canines can outperform these systems at sampling and detecting the low vapor pressure explosives and drugs, such as RDX, PETN, cocaine, and MDMA, because these biological detectors target the volatile signature compounds available in the headspace rather than the non-volatile parent compounds of explosives and drugs.^ In this dissertation research volatile signature compounds available in the headspace over explosive and drug samples were detected using SPME as a headspace sampling tool coupled to an IMS analyzer. A Genetic Algorithm (GA) technique was developed to optimize the operating conditions of a commercial IMS (GE Itemizer 2), leading to the successful detection of plastic explosives (Detasheet, Semtex H, and C-4) and illicit drugs (cocaine, MDMA, and marijuana). Short sampling times (between 10 sec to 5 min) were adequate to extract and preconcentrate sufficient analytes (> 20 ng) representing the volatile signatures in the headspace of a 15 mL glass vial or a quart-sized can containing ≤ 1 g of the bulk explosive or drug.^ Furthermore, a research grade IMS with flexibility for changing operating conditions and physical configurations was designed and fabricated to accommodate future research into different analytes or physical configurations. The design and construction of the FIU-IMS were facilitated by computer modeling and simulation of ion’s behavior within an IMS. The simulation method developed uses SIMION/SDS and was evaluated with experimental data collected using a commercial IMS (PCP Phemto Chem 110). The FIU-IMS instrument has comparable performance to the GE Itemizer 2 (average resolving power of 14, resolution of 3 between two drugs and two explosives, and LODs range from 0.7 to 9 ng). ^ The results from this dissertation further advance the concept of targeting volatile components to presumptively detect the presence of concealed bulk explosives and drugs by SPME-IMS, and the new FIU-IMS provides a flexible platform for future IMS research projects.^

Relevância:

100.00% 100.00%

Publicador:

Resumo:

The present paper investigates post-Soviet non-state and state higher educational institutions in terms of students’ perceptions of school curriculum, quality of teaching, available educational resources and overall organization in their higher educational institutions.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Since the 1970s various industry studies have indicated that the vacation ownership industry has enjoyed unprecedented growth in unit sales, resort growth, and the number of owners (American Resort Devleopment Association [ARDA], 2007; ARDA, 2009a; ARDA, 2009b). However, due to the recent economic downturn these growth metrics are no longer obtainable. This external impact has caused developers to retrench and therefore reflect upon their existing product and service offerings, financial metrics, and consumer markets (ARDA, 2010a; ARDA 2010b). The crux of these findings indicates that the industry has shifted to maintaining and enhancing product and service offerings as a reaction to changing economic conditions. The findings reported in the body of this manuscript represent product and service preferences as collected from a random data pull of their existing ownership base. The study also revealed current preferences of timeshare owners with relation to services provided and products/amenities offered. Management implications and limitations of the current study are discussed.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

In the 1980s, government agencies sought to utilize research on drug use prevention to design media campaigns. Enlisting the assistance of the national media, several campaigns were designed and initiated to bring anti-drug use messages to adolescents in the form of public service advertising. This research explores the sources of information selected by adolescents in grades 7 through 12 and how the selection of media and other sources of information relate to drug use behavior and attitudes and perceptions related to risk/harm and disapproval of friends' drug-using activities.^ Data collected from 1989 to 1992 in the Miami Coalition School Survey provided a random selection of secondary school studies. The responses of these students were analyzed using multivariate statistical techniques.^ Although many of the students selected media as the source for most of their information on the effects of drugs on the people who use them, the selection of media was found to be positively related to alcohol use and negatively related to marijuana use. The selection of friends, brothers, or sisters was a statistically significant source for adolescents who smoke cigarettes, use alcohol or marijuana.^ The results indicate that the anti-drug use messages received by students may be canceled out by media messages perceived to advocate substance use and that a more persuasive source of information for adolescents may be friends and siblings. As federal reports suggest that the economic costs of drug abuse will reach an estimated $150 billion by 1997 if current trends continue, prevention policy that addresses the glamorization of substance use remains a national priority. Additionally, programs that advocate prevention within the peer cluster must be supported, as peers are an influential source for both inspiring and possibly preventing drug use behavior. ^

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Television (TV) reaches more people than any other medium which makes it an important source of health information. Since TV ads often offer information obliquely, this study investigated implied health messages found in food and nutrition TV ads. The goals were to determine the proportion of food and nutrition ads among all TV advertising and to use content analysis to identify their implied messages and health claims. A randomly selected sample of TV ads were collected over a 28-day period beginning May 8, 1987. The sample contained 3547 ads; 725 (20%) were food-related. All were analyzed. About 10% of food-related TV ads contained a health claim. Twenty-five representative ads of the 725 food ads were also reviewed by 10 dietitians to test the reliability of the instrument. Although the dietitians agreed upon whether a health claim existed in a televised food ad, their agreement was poor when evaluating the accuracy of the claim. The number of food-related ads dropped significantly on Saturday, but the number of alcohol ads rose sharply on Saturday and Sunday. Snack ads were shown more often on Thursday, but snack commercials were also numerous on Saturday morning and afternoon, as were cereal ads. Ads for snack foods accounted for the greatest proportion of ads (20%) while fast food accounted for only 7%. Alcohol constituted about 9% of all food and nutrition ads.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

© 2016 Springer Science+Business Media New YorkResearchers studying mammalian dentitions from functional and adaptive perspectives increasingly have moved towards using dental topography measures that can be estimated from 3D surface scans, which do not require identification of specific homologous landmarks. Here we present molaR, a new R package designed to assist researchers in calculating four commonly used topographic measures: Dirichlet Normal Energy (DNE), Relief Index (RFI), Orientation Patch Count (OPC), and Orientation Patch Count Rotated (OPCR) from surface scans of teeth, enabling a unified application of these informative new metrics. In addition to providing topographic measuring tools, molaR has complimentary plotting functions enabling highly customizable visualization of results. This article gives a detailed description of the DNE measure, walks researchers through installing, operating, and troubleshooting molaR and its functions, and gives an example of a simple comparison that measured teeth of the primates Alouatta and Pithecia in molaR and other available software packages. molaR is a free and open source software extension, which can be found at the doi:10.13140/RG.2.1.3563.4961(molaR v. 2.0) as well as on the Internet repository CRAN, which stores R packages.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

We refined the strontium isotope seawater curve for the Paleocene and early Eocene by analysis of samples recovered from the Walvis Ridge during Ocean Drilling Project (ODP) Leg 208. The highest 87Sr/86Sr values occurred in the earliest Paleocene at 65 Ma and generally decreased throughout the Paleocene, reaching minimum values between 53 and 51 Ma in the early Eocene before beginning to increase again at 50 Ma. A plausible explanation for the 87Sr/86Sr decrease between 65 and 51 Ma is increased rates of hydrothermal activity and/or the eruption and weathering of large igneous provinces (e.g., Deccan Traps and North Atlantic). Strontium isotope variations closely parallel sea level and benthic d18O changes during the late Paleocene and early Eocene, supporting previous studies linking tectonic reorganization and increased volcanism to high sea level, high CO2, and warm global temperatures.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

This project is about Fast and Female, a community-based girls’ sport organization, that focuses on empowering girls through sport. In this thesis I produce a discourse analysis from interviews with six expert sportswomen and a textual analysis of the organization’s online content – including its social media pages. I ground my analysis in poststructural theory as explained by Chris Weedon (1997) and in literature that helps contextualize and better define empowerment (Collins, 2000; Cruikshank, 1999; Hains, 2012; Sharma, 2008; Simon, 1994) and neoliberalism (Silk & Andrews, 2012). My analysis in this project suggests that Fast and Female develops a community through online and in-person interaction. This community is focused on girls’ sport and empowerment, but, as the organization is situated in a neoliberal context, organizers must take extra consideration in order for the organization to develop a girls’ sport culture that is truly representative of the desires and needs of the participants rather than implicit neoliberal values. It is important to note that Fast and Female does not identify as a feminist organization. Through this thesis I argue that Fast and Female teaches girls that sport is empowering – but, while the organization draws on “empowerment,” a term often used by feminists, it promotes a notion of empowerment that teaches female athletes how to exist within current mainstream and sporting cultures, rather than encouraging them to be empowered female citizens who learn to question and challenge social inequity. I conclude my thesis with suggestions for Fast and Female to encourage empowerment in spite of the current neoliberal situation. I also offer a goal-setting workbook that I developed to encourage girls to set goals while thinking about their communities rather than just themselves.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Aim: Excipients are used to overcome the chemical, physical and microbiological challenges posed by developing formulated medicines. Both methyl and propyl paraben are commonly used in pediatric liquid formulations. There is no data on systemic exposure to parabens in neonates. The European Study of Neonatal Exposure to Excipients project has investigated this. Results & methodology: DBS sampling was used to collect opportunistic blood samples. Parabens were extracted from the DBS and analyzed using a validated LC-MS/MS assay.

Discussion & Conclusion: The above assay was applied to analyze neonatal DBS samples. The blood concentrations of parabens in neonates confirm systemic exposure to parabens following administration of routine medicines.