994 resultados para science experiments


Relevância:

20.00% 20.00%

Publicador:

Resumo:

Toxic blooms of Lyngbya majuscula occur in coastal areas worldwide and have major ecological, health and economic consequences. The exact causes and combinations of factors which lead to these blooms are not clearly understood. Lyngbya experts and stakeholders are a particularly diverse group, including ecologists, scientists, state and local government representatives, community organisations, catchment industry groups and local fishermen. An integrated Bayesian Network approach was developed to better understand and model this complex environmental problem, identify knowledge gaps, prioritise future research and evaluate management options.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

In response to a growing interest in art and science interactions and transdisciplinary research strategies, this research project examines the critical and conceptual affordances of ArtScience practice and outlines a new experiential methodology for practice-lead research using a framework of creative becoming. In doing so, the study contributes to the field of ArtScience and transdisciplinary practice, by providing new strategies for creative development and critical enquiry across art and science.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

In order to establish the influence of the drying air characteristics on the drying performance and fluidization quality of bovine intestine for pet food, several drying tests have been carried out in a laboratory scale heat pump assisted fluid bed dryer. Bovine intestine samples were heat pump fluidized bed dried at atmospheric pressure and at temperatures below and above the materials freezing points, equipped with a continuous monitoring system. The investigation of the drying characteristics have been conducted in the temperature range −10 to 25 ◦C and the airflow in the range 1.5–2.5 m/s. Some experiments were conducted as single temperature drying experiments and others as two stage drying experiments employing two temperatures. An Arrhenius-type equation was used to interpret the influence of the drying air temperature on the effective diffusivity, calculated with the method of slopes in terms of energy activation, and this was found to be sensitive to the temperature. The effective diffusion coefficient of moisture transfer was determined by the Fickian method using uni-dimensional moisture movement in both moisture, removal by evaporation and combined sublimation and evaporation. Correlations expressing the effective moisture diffusivity and drying temperature are reported. Bovine particles were characterized according to the Geldart classification and the minimum fluidization velocity was calculated using the Ergun Equation and generalized equation for all drying conditions at the beginning and end of the trials. Walli’s model was used to categorize stability of the fluidization at the beginning and end of the dryingv for each trial. The determined Walli’s values were positive at the beginning and end of all trials indicating stable fluidization at the beginning and end for each drying condition.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

The purpose of this study is to determine visual performance in water, including the influence of pupil size. The water en-vironment was simulated by placing a goggle filled with saline in front of eyes, with apertures placed at the front of the goggle. Correction factors were determined for the different magnification under this condition in order to to estimate vision in water. Experiments were conducted on letter visual acuity (7 participants), grating resolution (8 participants), and grating contrast sensitivity (1 participant). For letter acuity, mean loss in vision in water, compared to corrected vision in air, varied between 1.1 log minutes of arc resolution (logMAR) for a 1mm aperture to 2.2 logMAR for a 7mm aperture. The vision in minutes of arc was described well by a linear relationship with pupil size. For grating acuity, mean loss varied between 1.1 logMAR for a 2mm aperture to 1.2 logMAR for a 6mm aperture. Contrast sensitivity for a 2mm aperture dete-riorated as spatial frequency increased, with 2 log unit loss by 3 cycles/degree. Superimposed on this deterioration were depressions (notches) in sensitivity, with the first three notches occurring at 0.45, 0.8 and 1.3 cycles/degree with esti-mates for water of 0.39, 0.70 and 1.13 cycles/degree. In conclusion, vision in water is poor. It becomes worse as pupil size increases, but the effects are much more marked for letter targets than for grating targets.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Purpose: To determine visual performance in water, including the influence of pupil size. Method: The water environment was simulated by placing a goggle filled with saline in front of eyes, with apertures placed at the front of the goggle. Correction factors were determined for the different magnification under this condition to estimate vision in water. Experiments were conducted on letter visual acuity (7 participants), grating resolution (8 participants), and grating contrast sensitivity (1 participant). Results: For letter acuity, mean loss in vision in water, compared to corrected vision in air, varied between 1.1 log minutes of arc resolution (logMAR) for a 1mm aperture to 2.2 logMAR for a 7mm aperture. The vision in minutes of arc was described well by a linear relationship with pupil size. For grating acuity, mean loss varied between 1.1 logMAR for a 2mm aperture to 1.2 logMAR for a 6mm aperture. Contrast sensitivity for a 2mm aperture deteriorated as spatial frequency increased, with 2 log unit loss by 3 cycles/degree. Superimposed on this deterioration were depressions (notches) in sensitivity, with the first three notches occurring at 0.45, 0.8 and 1.3 cycles/degree and with estimates for water of 0.39, 0.70 and 1.13 cycles/degree. Conclusion: Vision in water is poor. It becomes worse as pupil size increases, but the effects are much more marked for letter targets than for grating targets.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Assessment of learning plays a dominant role in formal education in the forms of determining features of curriculum that are emphasized, pedagogic methods that teachers use with their students, and parents’ and employers’ understanding of how well students have performed. A common perception is that fair assessment applies the same mode of assessment and content focus for all students—the approach of assessments in international comparative studies of science achievement. This article examines research evidence demonstrating that the act of assessment is not neutral—different forms of assessment advantage or disadvantage groups of students on the basis of family backgrounds, gender, race, or disability. Assessment that implicitly or explicitly captures the social capital of the child serves to consolidate, not address, educational equity. The article provides an overview of ways that science curriculum focus and assessment can introduce bias in the identification of student achievement. It examines the effect of changes to curriculum and assessment approaches in science, and relationships between assessment of science and the cultural context of the student. Recommendations are provided for science–assessment research to address bias for different groups of students.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

The establishment and continuity of two international comparative assessments of science learning—the IEA’s TIMSS project and the OECD’s PISA project—have meant that there are now high-status reference points for other national and more local approaches to assessing the efficacy of science teaching and learning. Both projects, albeit with very different senses of what the outcome of science learning should be, have contributed positively and negatively to the current state of assessment of school science. The TIMSS project looks back at the science that is commonly included in the curricula of the participating countries. It is thus not about established school science nor about innovations in it. PISA is highly innovative looking, prospectively forward to see how students can use their science learning in everyday life situations. In this chapter some of these positives and negatives are discussed.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

The intentions of the science curriculum are very often constrained by the forms of student learning that are required by, or are currently available within, the system of education. Furthermore, little attention is given to developing new approaches to assessment that would encourage these good intentions. In this chapter, we argue that achieving this broadening of the intentions of science education will require a diversity of assessment techniques and that only a profile of each student’s achievement will capture the range of intended learnings. We explore a variety of assessment modes that match some of these new aspects of science learning and that also provide students with both formative information and a more comprehensive and authentic summative profile of their performances. Our discussion is illustrated with research-based examples of assessment practice in relation to three aspects of science education that are increasingly referred to in curriculum statements as desirable human dimensions of science: context-based science education, decision-making processes and socioscientific issues and integrated science education. We conclude with some notes on what these broader kinds of assessment mean for teachers and the support they would need to include them in their day-to-day practices in the science classrooms if, and when, the mainstream of science teaching and learning takes these curricular intentions seriously.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Introduction Novel ecosystems that contain new combinations of invasive alien plants (IAPs) present a challenge for managers. Yet, control strategies that focus on the removal of the invasive species and/or restoring historical disturbance regimes often do not provide the best outcome for long-term control of IAPs and the promotion of more desirable plant species. Methods This study seeks to identify the primary drivers of grassland invasion to then inform management practices toward the restoration of native ecosystems. By revisiting both published and unpublished data from experiments and case studies within mainly an Australian context for native grassland management, we show how alternative states models can help to design control strategies to manage undesirable IAPs by manipulating grazing pressure. Results Ungulate grazing is generally considered antithetical to invasive species management because in many countries where livestock production is a relatively new disturbance to grasslands (such as in Australia and New Zealand as well as Canada and the USA), selective grazing pressure may have facilitated opportunities for IAPs to establish. We find that grazing stock can be used to manipulate species composition in favour of the desirable components in pastures, but whether grazing is rested or strategically applied depends on the management goal, sizes of populations of the IAP and more desirable species, and climatic and edaphic conditions. Conclusions Based on our findings, we integrated these relationships to develop a testable framework for managing IAPs with strategic grazing that considers both the current state of the plant community and the desired future state—i.e. the application of the principles behind reclamation, rehabilitation, restoration or all three—over time.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Waterfalls and rapids are a subject of study by scientists and scholars from a variety of academic and professional backgrounds. Unlike cave research, known as speleology, which also involves many different disciplines, the study of waterfalls is not generally regarded as a distinct branch of knowledge. Long neglected as subjects of research, waterfalls have received considerable attention since the 1980s. This paper traces the study of waterfalls from the late eighteenth century, a period when both a scientific and an aesthetic interest in landscape developed in Europe, to the present. The work of geographers, geologists and others who studied landforms and landscapes is examined, with particular attention to those who expressed a special interest in waterfalls, notably Alexander von Humboldt. The study argues that the scientific and aesthetic approaches to landscape research are not incompatible and supports the view that both are necessary for a full understanding and appreciation of the environment in which we live.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Process-Aware Information Systems (PAISs) support executions of operational processes that involve people, resources, and software applications on the basis of process models. Process models describe vast, often infinite, amounts of process instances, i.e., workflows supported by the systems. With the increasing adoption of PAISs, large process model repositories emerged in companies and public organizations. These repositories constitute significant information resources. Accurate and efficient retrieval of process models and/or process instances from such repositories is interesting for multiple reasons, e.g., searching for similar models/instances, filtering, reuse, standardization, process compliance checking, verification of formal properties, etc. This paper proposes a technique for indexing process models that relies on their alternative representations, called untanglings. We show the use of untanglings for retrieval of process models based on process instances that they specify via a solution to the total executability problem. Experiments with industrial process models testify that the proposed retrieval approach is up to three orders of magnitude faster than the state of the art.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Microwave power is used for heating and drying processes because of its faster and volumetric heating capability. Non-uniform temperature distribution during microwave application is a major drawback of these processes. Intermittent application of microwave potentially reduces the impact of non-uniformity and improves energy efficiency by redistributing the temperature. However, temperature re-distribution during intermittent microwave heating has not been investigated adequately. Consequently, in this study, a coupled electromagnetic with heat and mass transfer model was developed using the finite element method embedded in COMSOL-Multyphysics software. Particularly, the temperature redistribution due to intermittent heating was investigated. A series of experiments were performed to validate the simulation. The test specimen was an apple and the temperature distribution was closely monitored by a TIC (Thermal Imaging Camera). The simulated temperature profile matched closely with thermal images obtained from experiments.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Background The expansion of cell colonies is driven by a delicate balance of several mechanisms including cell motility, cell-to-cell adhesion and cell proliferation. New approaches that can be used to independently identify and quantify the role of each mechanism will help us understand how each mechanism contributes to the expansion process. Standard mathematical modelling approaches to describe such cell colony expansion typically neglect cell-to-cell adhesion, despite the fact that cell-to-cell adhesion is thought to play an important role. Results We use a combined experimental and mathematical modelling approach to determine the cell diffusivity, D, cell-to-cell adhesion strength, q, and cell proliferation rate, ?, in an expanding colony of MM127 melanoma cells. Using a circular barrier assay, we extract several types of experimental data and use a mathematical model to independently estimate D, q and ?. In our first set of experiments, we suppress cell proliferation and analyse three different types of data to estimate D and q. We find that standard types of data, such as the area enclosed by the leading edge of the expanding colony and more detailed cell density profiles throughout the expanding colony, does not provide sufficient information to uniquely identify D and q. We find that additional data relating to the degree of cell-to-cell clustering is required to provide independent estimates of q, and in turn D. In our second set of experiments, where proliferation is not suppressed, we use data describing temporal changes in cell density to determine the cell proliferation rate. In summary, we find that our experiments are best described using the range D = 161 - 243 ?m2 hour-1, q = 0.3 - 0.5 (low to moderate strength) and ? = 0.0305 - 0.0398 hour-1, and with these parameters we can accurately predict the temporal variations in the spatial extent and cell density profile throughout the expanding melanoma cell colony. Conclusions Our systematic approach to identify the cell diffusivity, cell-to-cell adhesion strength and cell proliferation rate highlights the importance of integrating multiple types of data to accurately quantify the factors influencing the spatial expansion of melanoma cell colonies.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

In 2012, Queensland University of Technology (QUT) committed to the massive project of revitalizing its Bachelor of Science (ST01) degree. Like most universities in Australia, QUT has begun work to align all courses by 2015 to the requirements of the updated Australian Qualifications Framework (AQF) which is regulated by the Tertiary Education Quality and Standards Agency (TEQSA). From the very start of the redesigned degree program, students approach scientific study with an exciting mix of theory and highly topical real world examples through their chosen “grand challenge.” These challenges, Fukushima and nuclear energy for example, are the lenses used to explore science and lead to 21st century learning outcomes for students. For the teaching and learning support staff, our grand challenge is to expose all science students to multidisciplinary content with a strong emphasis on embedding information literacies into the curriculum. With ST01, QUT is taking the initiative to rethink not only content but how units are delivered and even how we work together between the faculty, the library and learning and teaching support. This was the desired outcome but as we move from design to implementation, has this goal been achieved? A main component of the new degree is to ensure scaffolding of information literacy skills throughout the entirety of the three year course. However, with the strong focus on problem-based learning and group work skills, many issues arise both for students and lecturers. A move away from a traditional lecture style is necessary but impacts on academics’ workload and comfort levels. Therefore, academics in collaboration with librarians and other learning support staff must draw on each others’ expertise to work together to ensure pedagogy, assessments and targeted classroom activities are mapped within and between units. This partnership can counteract the tendency of isolated, unsupported academics to concentrate on day-to-day teaching at the expense of consistency between units and big picture objectives. Support staff may have a more holistic view of a course or degree than coordinators of individual units, making communication and truly collaborative planning even more critical. As well, due to staffing time pressures, design and delivery of new curriculum is generally done quickly with no option for the designers to stop and reflect on the experience and outcomes. It is vital we take this unique opportunity to closely examine what QUT has and hasn’t achieved to be able to recommend a better way forward. This presentation will discuss these important issues and stumbling blocks, to provide a set of best practice guidelines for QUT and other institutions. The aim is to help improve collaboration within the university, as well as to maximize students’ ability to put information literacy skills into action. As our students embark on their own grand challenges, we must challenge ourselves to honestly assess our own work.