2,361 research outputs found
Responsibility for regional waste generation: A single region extended input-output analysis with uni-directional trade flows
The paper uses a regional input-output (IO) framework and data derived on waste generation by industry to examine regional accountability for waste generation. In addition to estimating a series of industry output-waste coefficients, the paper considers two methods for waste attribution but focuses first on one (trade endogenised linear attribution system (TELAS)) that permits a greater focus on private and public final consumption as the main exogenous driver of waste generation. Second, the paper uses a domestic technology assumption (DTA) to consider a regional âwaste footprintâ where local consumption requirements are assumed to be met through domestic production.waste attribution; regional economy; input-output analysis; Wales
Role of Schizosaccharomyces pombe RecQ homolog recombination and checkpoint genes in UV Damage tolerance
The cellular responses to DNA damage are complex and include direct DNA repair pathways that remove the damage and indirect damage responses which allow cells to survive DNA damage that has not been, or cannot be, removed. We have identified the gene mutated in the rad12.502 strain as a Schizosaccharomyces pombe recQ homolog. The same gene (designated rqh1) is also mutated in the hus2.22 mutant. We show that Rqh1 is involved in a DNA damage survival mechanism which prevents cell death when UV-induced DNA damage cannot be removed. This pathway also requires the correct functioning of the recombination machinery and the six checkpoint tad gene products plus the Cds1 kinase. Our data suggest that Rqh1 operates during S phase as part of a mechanism which prevents DNA damage causing cell lethality. This process may involve the bypass of DNA damage sites by the replication fork. Finally, in contrast with the reported literature, we do not find that rqh1 (rad12) mutant cells are defective in UV dimer endonuclease activity
Reply to "Comment on 'Precision measurement of the Casimir-Lifshitz force in a fluid'"
We have reviewed the Comment of Geyer et al. [arXiv:0708.1548] concerning our
recent work [Phys. Rev. A 75, 060102 (R) (2007)], and while we disagree with
their criticisms, we acknowledge them for giving us the opportunity to add
interesting addition material and a more detailed description of our
experiment. We describe further our calculation and explain why a more
sophisticated model is not warranted. We also present detailed experiments on
the effects of electrostatic forces in our measurements and show that the
contribution due to work function differences is small and that the residual
electrostatic force is dominated by trapped charges and external fields.
Finally, we estimate the effect of double layer interactions. These additional
calculations and measurements support our original conclusion that the
experimental results are consistent with the Lifshitz theory
Research into the views of two child reference groups on the arts in research concerning wellbeing
Introduction: This paper explores an aspect of the process and outcomes of two childrenâs reference groups: the ways the young members of the reference groups consider the role of the arts in research concerning wellbeing.
Methods: Two case studies draw on qualitative data from the projects offering insight into child reference group work over the life of a research project: from recommendations to implementation.
Results: The findings demonstrate that both reference groups enabled the research to achieve a fuller engagement with meaning making in relation to data collection by consulting with children.
Conclusion: The data reveal how the members offered âinsider knowledgeâ to the researchers concerning the role of the arts in research concerning wellbeing. Themes within the analysis about the impact of the reference groupâs knowledge and recommendations on the research projectâs data collection methods include the role of the arts connected to empathy, safety and confidentiality and in relation to difference and choice
Quantum electrodynamical torques in the presence of Brownian motion
Quantum fluctuations of the electromagnetic field give rise to a zero-point energy that persists even in the absence of electromagnetic sources. One striking consequence of the zero-point energy is manifested in the Casimir force, which causes two electrically neutral metallic plates to attract in order to reduce the zero-point energy. A second, less well-known, effect is a torque that arises between two birefringent materials with in-plane optical anisotropy as a result of the zero-point energy. In this paper, we discuss the influence of Brownian motion on two birefringent plates undergoing quantum electrodynamical (QED) rotation as a result of the system's zero-point energy. Direct calculations for the torque are presented, and preliminary experiments are discussed. © IOP Publishing Ltd and Deutsche Physikalische Gesellschaft
Implementation of a geometrically informed and energetically constrained mesoscale eddy parameterization in an ocean circulation model
The global stratification and circulation of the ocean and their
sensitivities to changes in forcing depend crucially on the representation of
the mesoscale eddy field. Here, a geometrically informed and energetically
constrained parameterization framework for mesoscale eddies --- termed
GEOMETRIC --- is proposed and implemented in three-dimensional primitive
equation channel and sector models. The GEOMETRIC framework closes mesoscale
eddy fluxes according to the standard Gent--McWilliams scheme, but with the
eddy transfer coefficient constrained by the depth-integrated eddy energy
field, provided through a prognostic eddy energy budget evolving with the mean
state. It is found that coarse resolution calculations employing GEOMETRIC
broadly reproduce model sensitivities of the eddy permitting reference
calculations in the emergent circumpolar transport, meridional overturning
circulation profile and the depth-integrated eddy energy signature; in
particular, eddy saturation emerges in the sector configuration. Some
differences arise, attributed here to the simple prognostic eddy energy budget
employed, to be improved upon in future investigations. The GEOMETRIC framework
thus proposes a shift in paradigm, from a focus on how to close for eddy
fluxes, to focusing on the representation of eddy energetics.Comment: 19 pages, 9 figures, submitted to Journal of Physical Oceanography;
comments welcome. (Copyright statement: see section 7a of
https://www.ametsoc.org/ams/index.cfm/publications/ethical-guidelines-and-ams-policies/ams-copyright-policy/
The Limpopo Low-Level Jet: mean climatology and role in water vapor transport
Low-level jets (LLJs) are well established as critical features of regional climates globally. However, across sub-Saharan Africa, LLJs have received relatively little attention, in part due to a lack of data. Utilizing high-resolution reanalysis data, this paper develops the first climatology of a neglected feature of the southern African circulation â the Limpopo LLJ â and investigates its role in delivering water vapor to the continental interior. We demonstrate that the LLJ has a clear diurnal cycle and is a regular feature of the circulation throughout the year, forming on 80.9% of days. The pressure gradient between southern Mozambique and the continental interior acts as a first-order control on the annual cycle of jet strength, which peaks in October, achieving average maximum windspeeds of 15.8 m.sâ1 at the core. Water vapor transport follows the same clear diurnal cycle, with at least 72% occurring over 18:00â08:00, and is closely related to jet strength: On average the strongest jet events advect 1.04 Ă 1012 kg (1.02 Ă 1012 kg) more moisture each night than the weakest in October-December (January-March). Strong jet events are typically linked to ridging anticyclones along the east coast of South Africa and are associated with increased rainfall in central and southern Botswana and northern South Africa the following day
Precision measurement of the Casimir-Lifshitz force in a fluid
The Casimir force, which results from the confinement of the quantum
mechanical zero-point fluctuations of the electromagnetic fields, has received
significant attention in recent years for its effect on micro- and nano-scale
mechanical systems. With few exceptions, experimental observations have been
limited to conductive bodies interacting separated by vacuum or air. However,
interesting phenomena including repulsive forces are expected to exist in
certain circumstances between metals and dielectrics when the intervening
medium is not vacuum. In order to better understand the effect of the Casimir
force in such situations and to test the robustness of the generalized
Casimir-Lifshitz theory, we have performed the first precision measurements of
the Casimir force between two metals immersed in a fluid. For this situation,
the measured force is attractive and is approximately 80% smaller than the
force predicted by Casimir for ideal metals in vacuum. We present experimental
results and find them to be consistent with Lifshitz's theory.Comment: 6 pages, 3 figures. (version before final publication
Morpheus: Advancing Technologies for Human Exploration
NASA's Morpheus Project has developed and tested a prototype planetary lander capable of vertical takeoff and landing. Designed to serve as a vertical testbed (VTB) for advanced spacecraft technologies, the vehicle provides a platform for bringing technologies from the laboratory into an integrated flight system at relatively low cost. This allows individual technologies to mature into capabilities that can be incorporated into human exploration missions. The Morpheus vehicle is propelled by a LOX/Methane engine and sized to carry a payload of 1100 lb to the lunar surface. In addition to VTB vehicles, the Project s major elements include ground support systems and an operations facility. Initial testing will demonstrate technologies used to perform autonomous hazard avoidance and precision landing on a lunar or other planetary surface. The Morpheus vehicle successfully performed a set of integrated vehicle test flights including hot-fire and tethered hover tests, leading up to un-tethered free-flights. The initial phase of this development and testing campaign is being conducted on-site at the Johnson Space Center (JSC), with the first fully integrated vehicle firing its engine less than one year after project initiation. Designed, developed, manufactured and operated in-house by engineers at JSC, the Morpheus Project represents an unprecedented departure from recent NASA programs that traditionally require longer, more expensive development lifecycles and testing at remote, dedicated testing facilities. Morpheus testing includes three major types of integrated tests. A hot-fire (HF) is a static vehicle test of the LOX/Methane propulsion system. Tether tests (TT) have the vehicle suspended above the ground using a crane, which allows testing of the propulsion and integrated Guidance, Navigation, and Control (GN&C) in hovering flight without the risk of a vehicle departure or crash. Morpheus free-flights (FF) test the complete Morpheus system without the additional safeguards provided during tether. A variety of free-flight trajectories are planned to incrementally build up to a fully functional Morpheus lander capable of flying planetary landing trajectories. In FY12, these tests will culminate with autonomous flights simulating a 1 km lunar approach trajectory, hazard avoidance maneuvers and precision landing in a prepared hazard field at the Kennedy Space Center (KSC). This paper describes Morpheus integrated testing campaign, infrastructure, and facilities, and the payloads being incorporated on the vehicle. The Project s fast pace, rapid prototyping, frequent testing, and lessons learned depart from traditional engineering development at JSC. The Morpheus team employs lean, agile development with a guiding belief that technologies offer promise, but capabilities offer solutions, achievable without astronomical costs and timelines
Project Morpheus: Lessons Learned in Lander Technology Development
NASA's Morpheus Project has developed and tested a prototype planetary lander capable of vertical takeoff and landing, that is designed to serve as a testbed for advanced spacecraft technologies. The lander vehicle, propelled by a LOX/Methane engine and sized to carry a 500kg payload to the lunar surface, provides a platform for bringing technologies from the laboratory into an integrated flight system at relatively low cost. Designed, developed, manufactured and operated in-house by engineers at Johnson Space Center, the initial flight test campaign began on-site at JSC less than one year after project start. After two years of testing, including two major upgrade periods, and recovery from a test crash that caused the loss of a vehicle, flight testing will evolve to executing autonomous flights simulating a 500m lunar approach trajectory, hazard avoidance maneuvers, and precision landing, incorporating the Autonomous Landing and Hazard Avoidance (ALHAT) sensor suite. These free-flights are conducted at a simulated planetary landscape built at Kennedy Space Center's Shuttle Landing Facility. The Morpheus Project represents a departure from recent NASA programs and projects that traditionally require longer development lifecycles and testing at remote, dedicated testing facilities. This paper expands on the project perspective that technologies offer promise, but capabilities offer solutions. It documents the integrated testing campaign, the infrastructure and testing facilities, and the technologies being evaluated in this testbed. The paper also describes the fast pace of the project, rapid prototyping, frequent testing, and lessons learned during this departure from the traditional engineering development process at NASA's Johnson Space Center
- âŠ