2,857 research outputs found

    Baroclinic geostrophic adjustment in a rotating circular basin

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    Baroclinic geostrophic adjustment in a rotating circular basin is investigated in a laboratory study. The adjustment process consists of a linear phase before advective and dissipative effects dominate the response for longer time. This work describes in detail the hydrodynamics and energetics of the linear phase of the adjustment process of a two-layer fluid from an initial step height discontinuity in the density interface DeltaH to a final response consisting of both geostrophic and fluctuating components. For a forcing lengthscale r(f) equal to the basin radius R-0, the geostrophic component takes the form of a basin-scale double gyre while the fluctuating component is composed of baroclinic Kelvin and Poincare waves. The Burger number S=R/r(f) (R is the baroclinic Rossby radius of deformation) and the dimensionless forcing amplitude epsilon = DeltaH/H-1 (H-1 is the upper-layer depth) characterize the response of the adjustment process. In particular, comparisons between analytical solutions and laboratory measurements indicate that for time tau: 1 < tau < S-1 (tau is time scaled by the inertial period 2pi/f), the basin-scale double gyre is established, followed by a period where the double gyre is sustained, given by S-1 < tau < 2epsilon(-1) for a moderate forcing and S-1 < tau < tau(D) for a weak forcing (tau(D) is the dimensionless dissipation timescale due to Ekman damping). The analytical solution is used to calculate the energetics of the baroclinic geostrophic adjustment. The results are found to compare well with previous studies with partitioning of energy between the geostrophic and fluctuating components exhibiting a strong dependence on S. Finally, the outcomes of this study are considered in terms of their application to lakes influenced by the rotation of the Earth

    The Eco-classroom project: Fostering student participation through education for sustainability

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    This thesis investigates learning and other outcomes in participants, particularly students (9-11 years), as a result of their involvement in an education for sustainability (EfS) co-design and build project at their primary school, in New Zealand, which was conducted within the Enviroschools Programme. The research focused on four areas that distinguished the project: sustainability learning as the issue, participatory practice as the method, design as the process and community partnerships as the sphere of involvement. Each of these was considered in terms of its influence on learning that was either cognitively-based (knowledge), psychomotor (skills) or affective (attitudes and values). This led to the set-up of a matrix to collect qualitative data that was gathered using a narrative inquiry method of collecting participants stories. This included focus groups with students who were part of the Eco-building Working Party, interviews with key adults from the school and the wider community, survey questionaires to parents of the focus group students, and other observations and materials. Findings demonstrated a correlation between the set-up and execution of the eco-classroom project and the Danish-developed pedagogical EfS concept of Action Competence. This was indicated through the authentic, relevant and democratic action-taking focus of the eco-classroom project that is linked to making learning transformations, which have been established as being more likely to lead to genuine changes in behaviour towards the environment. Also in agreement with an action competence approach was the strong focus in the project on both individual and collective learning. This was partly a result of the process-focused nature of the project, which was related to the learning mandate and commitment to a democratic process with students. The project ran for a number of years with annually changing groups of students, who all had different experiences. The teacher used ‘peer education’ and reflective tools to manage the ‘changeover’ positively, give depth and breadth to learning and ensure the project was truly collaborative. Student learning occurred in all three learning domains and included EfS learning (particularly about aspects of architecture and the built environment), learning about the process of design, and cross-disciplinary learning that included skills such as leadership, teamwork and public speaking. Adult participants also gained from their involvement in the project. The embedding of learning in the project within the New Zealand Curriculum, provided evidence of the flexible and multidisciplinary nature of EfS. Finally, a number of key characteristics were identified as contributing significantly to learning in the project

    Hydrological Investigations at Biafo Glacier, Karakoram Range, Himalaya; an Important Source of Water For the Indus River

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    Over 80% of the flow of the Upper Indus River is derived from less than 20% of its area: essentially from zones of heavy snowfall and glacierized basins above 3500 m elevation. The trans-Himalaya n contribution comes largely from an area of some 20000 km2 of glacierized basins, mostly along the axis of the Greater Karakoram range and especially from 20-30 of the largest glacier basins. Very few glaciological investigations have so far been undertaken in this the major glacierized region of Central Asia. Biafo Glacier, one of the largest of the Karakoram glaciers, drains south-eastwards from the central Karakoram crest. Its basin covers a total area of 853 km2 , 628 km2 of which are permanent snow and ice, with 68% of the glacier area forming the accumulation zone. This paper describes investigations of snow accumulation, ablation , glacier movement, and glacier depth undertaken in the period 1985-87 , set against a background of investigations carried out over the last 130 yea rs. Biafo Glacier differs from most of the other Karakoram glaciers in being nourished mainly by direct snowfall rather than by avalanching; this has the advantage of allowing extensive investigation of accumulation over a broad range of altitude. Snow-accumulation studies in the Biafo Glacier basin have indicated that annual accumulation varies from 0.9 to 1.9 m of water equivalent between 4650 and 5450 m a .. s.l. This suggests an annual moisture input above the equilibrium line of approximately 0.6 km3. Monopulse radar measurements indicate the presence of ice thickness as great as 1400 m at the equilibrium line, although these results may not be completely reliable . Mean surface velocity during the summer of 0.8 m d -I has been measured near to the equilibrium line. Calculations of annual ice flux through the vertical cross-profile at the equilibrium line indicate a throughput of 0.7 km3 a-I Estimates from stake ablation measurements also suggest that ice loss on Biafo Glacier is about 0.7 km3 a-I. The close agreement between these three sets of measurements is reassuring, indicating that the ablation zone of Biafo Glacier, whose area covers 0.09% of the whole Upper Indus basin, produces approximately 0.9% of the total run-off. However. it should be mentioned that this estimate does not include water originating from seasonal snow melt, e either above or below the equilibrium line, or from rainfall. Net annual ice losses due to wastage of the glacier since 1910 are probably of the order of 0.4-{).5 m a-I; this would represent between 12 and 15% of annual water yield from melting ice

    Intellectual Growth For Undergraduate Students: Evaluation Results From An Undergraduate Research Conference

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    We describe the development and evaluation of the university-wide, weeklong undergraduate research conference at the University of New Hampshire. Despite increases nationally in the number of undergraduate research conferences (URC), there has been little research examining the social and educational impact of these events on student presenters. We describe the development and evaluation of the university-wide, weeklong URC at the University of New Hampshire. A survey administered to URC participants over a four year period revealed that research culminating in a presentation at the URC was one of the more influential events students experienced during their undergraduate years and students realized a high level of satisfaction from presenting at the URC

    Constraining recent lead pollution sources in the North Pacific using ice core stable lead isotopes

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    Trends and sources of lead (Pb) aerosol pollution in the North Pacific rim of North America from 1850 to 2001 are investigated using a high-resolution (subannual to annual) ice core record recovered from Eclipse Icefield (3017 masl; St. Elias Mountains, Canada). Beginning in the early 1940s, increasing Pb concentration at Eclipse Icefield occurs coevally with anthropogenic Pb deposition in central Greenland, suggesting that North American Pb pollution may have been in part or wholly responsible in both regions. Isotopic ratios (208Pb/207Pb and 206Pb/207Pb) from 1970 to 2001 confirm that a portion of the Pb deposited at Eclipse Icefield is anthropogenic, and that it represents a variable mixture of East Asian (Chinese and Japanese) emissions transported eastward across the Pacific Ocean and a North American component resulting from transient meridional atmospheric flow. Based on comparison with source material Pb isotope ratios, Chinese and North American coal combustion have likely been the primary sources of Eclipse Icefield Pb over the 1970–2001 time period. The Eclipse Icefield Pb isotope composition also implies that the North Pacific mid-troposphere is not directly impacted by transpolar atmospheric flow from Europe. Annually averaged Pb concentrations in the Eclipse Icefield ice core record show no long-term trend during 1970–2001; however, increasing 208Pb/207Pb and decreasing 206Pb/207Pb ratios reflect the progressive East Asian industrialization and increase in Asian pollutant outflow. The post-1970 decrease in North American Pb emissions is likely necessary to explain the Eclipse Icefield Pb concentration time series. When compared with low (lichen) and high (Mt. Logan ice core) elevation Pb data, the Eclipse ice core record suggests a gradual increase in pollutant deposition and stronger trans-Pacific Asian contribution with rising elevation in the mountains of the North Pacific rim

    Diabetes and artificial intelligence (AI) beyond the closed loop: A review of the landscape, promise and challenges for AI-supported management and self-care for all diabetes types.

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    The discourse amongst diabetes specialists and academics regarding technology and artificial intelligence (AI) typically centres around the 10% of people with diabetes who have type 1 diabetes, focusing on glucose sensors, insulin pumps and, increasingly, closed-loop systems. This focus is reflected in conference topics, strategy documents, technology appraisals and funding streams. What is often overlooked is the wider application of data and AI, as demonstrated through published literature and emerging marketplace products, that offers promising avenues for enhanced clinical care, health-service efficiency and cost-effectiveness. This review provides an overview of AI techniques and explores the use and potential of AI and data-driven systems in a broad context, covering all diabetes types, encompassing: (1) patient education and self-management; (2) clinical decision support systems and predictive analytics, including diagnostic support, treatment and screening advice, complications prediction; and (3) the use of multimodal data, such as imaging or genetic data. The review provides a perspective on how data- and AI-driven systems could transform diabetes care in the coming years and how they could be integrated into daily clinical practice. We discuss evidence for benefits and potential harms, and consider existing barriers to scalable adoption, including challenges related to data availability and exchange, health inequality, clinician hesitancy and regulation. Stakeholders, including clinicians, academics, commissioners, policymakers and those with lived experience, must proactively collaborate to realise the potential benefits that AI-supported diabetes care could bring, whilst mitigating risk and navigating the challenges along the way.</p

    The Butcher-Oemler Effect in High Redshift X-ray Selected Clusters

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    We are engaged in a wide-field, multi-colour imaging survey of X-ray selected clusters at intermediate and high redshift. We present blue fractions for the first 8 out of 29 clusters, covering almost a factor of 100 in X-ray luminosity. We find no correlation of blue fraction with redshift or X-ray luminosity. The lack of a correlation with LX_{X}, places strong constraints on the importance of ram-pressure stripping as a driver of the Butcher-Oemler effect.Comment: 4 pages, 4 figures, to be puplished in the proceedings of the ''Sesto 2001-Tracing Cosmic Evolution with Galaxy Clusters'', Sesto 3-6 July 2001, Italy, eds, Stefano Borgan

    Comparison of Visual Analog Pain Score Reported to Physician vs Nurse in Nonoperatively Treated Foot and Ankle Patients

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    Background: Patient reported outcome measures (PROMs) are taking a more prominent role in Orthopedics as health care seeks to define treatment outcomes. The Visual Analogue Scale (VAS) is considered a reliable measure of acute pain. A previous study found that operative candidates’ VAS pain score was significantly higher when reported to the surgeon compared to the nurse. This study’s aim is to examine whether this phenomenon occurs in nonoperative patients. We hypothesize that patients’ VAS scores reported to the surgeon and a nurse will be the same Methods: This study is a retrospective cohort of 201 consecutive nonoperative patients treated by a single surgeon. Patients were asked to rate pain intensity by a nurse followed by the surgeon using a horizontal VAS, 0 “no pain” to 10 worst pain”. Differences in reported pain levels were compared with data from the previous cohort of 201 consecutive operative patients. Results: The mean VAS score reported to the nurse was 3.2 whereas the mean VAS score reported to the surgeon was 4.2 (p\u3c.001). The mean difference in VAS scores reported for operative patients was 2.9, whereas the mean difference for nonoperative patients was 1.0 (p \u3c .001). Conclusion: This study found statistically significant differences between VAS scores reported to the surgeon versus the nurse in nonoperative patients which support the trend found in our previous study, where operative patients reported significantly higher scores to the surgeon. The mean difference between reported pain scores is significantly higher for operative patients compared to nonoperative patients
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