3,519 research outputs found

    Producing short and long run projections for the Ecological Footprint

    Get PDF
    The Ecological Footprint is a useful tool for public awareness of ecological pressures and for policymakers who aim to reduce them. In order to determine the potential effects of future actions and policies, it is necessary to construct scenarios of future global conditions, both in the short-term and long-term. This study develops two alternative methods for creating Ecological Footprint scenarios: first using asymmetric changes in simple economic output (GDP) to look at short-term projections; then using widely accepted scenarios from international agencies to develop long-term projections. Changes in GDP were found to be causal in determining changes in the Ecological Footprint, and this method can be used for nowcasting and projecting the future Ecological Footprint. Furthermore, it was found that the projections from different agencies can be combined under a single Ecological Footprint framework, but there are certain inconsistencies across projections that are highlighted. Lastly, the use of dynamic Ecological Footprint models based on computable general equilibrium models is explored as the preferred solution for the creation of policy-relevant tools

    Analyzing the Use and Impacts of Oakland Slow Streets and Potential Scalability Beyond Covid-19

    Get PDF
    This report presents the results of a mixed-methods study of the 2020-2022 Oakland Slow Streets program. An official response to the Covid-19 pandemic, the program used signs and temporary barricades to limit thru-traffic on 21 miles of city streets to create more and safer space for walking, cycling, and outdoor recreation. Researchers collected data throughout the summer of 2021 on seven designated slow streets plus one cross street and one control street for each – a total of 21 street segments representing conditions in seven different neighborhoods across Oakland. Data collection comprised in-person passerby counts, observations and photographs of local conditions, and logged traffic speed data. Findings vary widely across study sites. In certain cases, observed slow streets saw less car traffic or more bicycle/pedestrian use than one or both of their comparison streets, and in at least one case the slow street was clearly embraced by the local community and used as planners intended; in others the slow street was no different than neighboring streets. The study draws on these findings to identify local conditions that seem likely to make slow treet treatments more or less successful. However, acknowledging that all neighborhoods deserve safer streets and greater outdoor recreational opportunities, the authors argue that better community outreach must be implemented to ensure areas not predisposed to make full use of slow streets can have the opportunity to do so. The study also makes suggestions regarding the potential for rapid, low-cost bike and pedestrian street safety improvements going forward

    Charge rearrangement and screening in a quantum point contact

    Full text link
    Compressibility measurements, sensitive to charge rearrangements, are performed on a quantum point contact (QPC). Screening due to mobile charges in the QPC is quantitatively measured, using a second point contact to detect the screened electrical potential. These measurements are performed from pinch-off through the opening of the first few modes in the QPC. While the measured signal closely matches a Thomas-Fermi-Poisson prediction, deviations from the classical behavior, in the form of additional dips, are apparent near the openings of the different modes, with the largest dip at the opening of the first mode. Density functional calculations attribute the first dip to exchange interactions. The other dips reflect the diverging density of states at the opening of each one-dimensional mode, which affects both kinetic and exchange contributions to the energy.Comment: 6 pages, 5 figures. Published in PRL. Supplementary Information is included. Changes: Two references and journal reference adde

    Modification and pathways of Southern Ocean Deep Waters in the Scotia Sea

    Get PDF
    An unprecedented high-quality, quasi-synoptic hydrographic data set collected during the ALBATROSS cruise along the rim of the Scotia Sea is examined to describe the pathways of the deep water masses flowing through the region, and to quantify changes in their properties as they cross the sea. Owing to sparse sampling of the northern and southern boundaries of the basin, the modification and pathways of deep water masses in the Scotia Sea had remained poorly documented despite their global significance. Weddell Sea Deep Water (WSDW) of two distinct types is observed spilling over the South Scotia Ridge to the west and east of the western edge of the Orkney Passage. The colder and fresher type in the west, recently ventilated in the northern Antarctic Peninsula, flows westward to Drake Passage along the southern margin of the Scotia Sea while mixing intensely with eastward-flowing Circumpolar Deep Water (CDW) of the antarctic circumpolar current (ACC). Although a small fraction of the other WSDW type also spreads westward to Drake Passage, the greater part escapes the Scotia Sea eastward through the Georgia Passage and flows into the Malvinas Chasm via a deep gap northeast of South Georgia. A more saline WSDW variety from the South Sandwich Trench may leak into the eastern Scotia Sea through Georgia Passage, but mainly flows around the Northeast Georgia Rise to the northern Georgia Basin. In Drake Passage, the inflowing CDW displays a previously unreported bimodal property distribution, with CDW at the Subantarctic Front receiving a contribution of deep water from the subtropical Pacific. This bimodality is eroded away in the Scotia Sea by vigorous mixing with WSDW and CDW from the Weddell Gyre. The extent of ventilation follows a zonation that can be related to the CDW pathways and the frontal anatomy of the ACC. Between the Southern Boundary of the ACC and the Southern ACC Front, CDW cools by 0.15°C and freshens by 0.015 along isopycnals. The body of CDW in the region of the Polar Front splits after overflowing the North Scotia Ridge, with a fraction following the front south of the Falkland Plateau and another spilling over the plateau near 49.5°W. Its cooling (by 0.07°C) and freshening (by 0.008) in crossing the Scotia Sea is counteracted locally by NADW entraining southward near the Maurice Ewing Bank. CDW also overflows the North Scotia Ridge by following the Subantarctic Front through a passage just east of Burdwood Bank, and spills over the Falkland Plateau near 53°W with decreased potential temperature (by 0.03°C) and salinity (by 0.004). As a result of ventilation by Weddell Sea waters, the signature of the Southeast Pacific Deep Water (SPDW) fraction of CDW is largely erased in the Scotia Sea. A modified form of SPDW is detected escaping the sea via two distinct routes only: following the Southern ACC Front through Georgia Passage; and skirting the eastern end of the Falkland Plateau after flowing through Shag Rocks Passage

    The flow of the Antarctic circumpolar current over the North Scotia Ridge

    Get PDF
    The transports associated with the Subantarctic Front (SAF) and the Polar Front (PF) account for the majority of the volume transport of the Antarctic Circumpolar Current (ACC). After passing through Drake Passage, the SAF and the PF veer northward over the steep topography of the North Scotia Ridge. Interaction of the ACC with the North Scotia Ridge influences the sources of the Malvinas Current. This ridge is a major obstacle to the flow of deep water, with the majority of the deep water passing through the 3100 m deep gap in the ridge known as Shag Rocks Passage. Volume transports associated with these fronts were measured during the North Scotia Ridge Overflow Project, which included the first extensive hydrographic survey of the ridge, carried out in April and May 2003. The total net volume transport northward over the ridge was found to be . The total net transport associated with the SAF was approximately , and the total transport associated with the PF was approximately . Weddell Sea Deep Water was not detected passing through Shag Rocks Passage, contrary to some previous inferences

    Eddy heat fluxes from direct current measurements of the Antarctic Polar Front in Shag Rocks Passage

    Get PDF
    Determining meridional heat flux in the Southern Ocean is critical to the accurate understanding and model simulation of the global ocean. Mesoscale eddies provide a significant but poorly-defined contribution to this transport. An eighteen-month deep-water current meter array deployment in Shag Rocks Passage (53°S, 48°W) between May 2003 and November 2004 provides estimates of the eddy flux of heat across the Polar Front. We calculate a statistically nonzero (99% level), vertically coherent local poleward heat flux of 12.0 ± 5.8 kW m-2 within the eddy frequency band at ~2750 m depth. Exceeding previous deep-water estimates by up to an order of magnitude, this highlights the large spatial variation in flux estimates and illustrates that constriction of circumpolar fronts facilitates large eddy transfers of heat southwards

    Access to recreational physical activities by car and bus : an assessment of socio-spatial inequalities in mainland Scotland

    Get PDF
    Obesity and other chronic conditions linked with low levels of physical activity (PA) are associated with deprivation. One reason for this could be that it is more difficult for low-income groups to access recreational PA facilities such as swimming pools and sports centres than high-income groups. In this paper, we explore the distribution of access to PA facilities by car and bus across mainland Scotland by income deprivation at datazone level. GIS car and bus networks were created to determine the number of PA facilities accessible within travel times of 10, 20 and 30 minutes. Multilevel negative binomial regression models were then used to investigate the distribution of the number of accessible facilities, adjusting for datazone population size and local authority. Access to PA facilities by car was significantly (p<0.01) higher for the most affluent quintile of area-based income deprivation than for most other quintiles in small towns and all other quintiles in rural areas. Accessibility by bus was significantly lower for the most affluent quintile than for other quintiles in urban areas and small towns, but not in rural areas. Overall, we found that the most disadvantaged groups were those without access to a car and living in the most affluent areas or in rural areas

    Design, Synthesis, and Evaluation of Tetrasubstituted Pyridines as Potent 5-HT2C Receptor Agonists.

    Get PDF
    A series of pyrido[3,4-d]azepines that are potent and selective 5-HT2C receptor agonists is disclosed. Compound 7 (PF-04781340) is identified as a suitable lead owing to good 5-HT2C potency, selectivity over 5-HT2B agonism, and in vitro ADME properties commensurate with an orally available and CNS penetrant profile. The synthesis of a novel bicyclic tetrasubstituted pyridine core template is outlined, including rationale to account for the unexpected formation of aminopyridine 13 resulting from an ammonia cascade cyclization.We would like to thank the EPSRC (SVL, grant nÂş EP/K0099494/1 and nÂş EP/K039520/1) for financial support.This is the accepted manuscript. The final version is available from ACS at http://pubs.acs.org/doi/abs/10.1021/ml500507v
    • …
    corecore