15,943 research outputs found
The Quasi-Biennial Oscillation in atmospheric ozone
Examination of the relationship between tropical stratosphere zonal wind and ozone indicate a variable response in latitude with Northern Hemisphere tropics and polar regions and Southern Hemisphere mid-latitudes showing the strongest response with relatively weaker response at Northern Hemisphere mid-latitudes and the Southern Hemisphere tropics. In tropical regions, the west winds and ozone maxima are in phase while at higher latitudes, a more nearly out-of-phase relationship prevails. At subtropical and middle latitudes, the QBO in ozone does not appear to change phases with altitude. These features are suggestive of an interaction between the tropical zonal winds and poleward transport of horizontal eddies in conjunction with the annual poleward transport of ozone
Stephen Mumberson: early printworks
Series of Nineteen prints made through various relief printing methods(lino-cut, metal relief(deep etched metal relief) and wood cut works) produced in the late 1980's and early 1990's. Subject matter sourced from Africa, research into prime and art of non western origin, myth(mostly Northern European and classical) and the local environment of South London particularly the Brixton area after the riots in the early 1980's. These Sources featured both in the method and style of cutting the images and also in the sourcing of image construction
Teaching the Emergency Department Patient Experience: Needs Assessment from the CORD-EM Task Force.
INTRODUCTION: Since the creation of Hospital Consumer Assessment of Healthcare Providers and Systems (HCAHPS) patient satisfaction (PS) scores, patient experience (PE) has become a metric that can profoundly affect the fiscal balance of hospital systems, reputation of entire departments and welfare of individual physicians. While government and hospital mandates demonstrate the prominence of PE as a quality measure, no such mandate exists for its education. The objective of this study was to determine the education and evaluation landscape for PE in categorical emergency medicine (EM) residencies.
METHODS: This was a prospective survey analysis of the Council of Emergency Medicine Residency Directors (CORD) membership. Program directors (PDs), assistant PDs and core faculty who are part of the CORD listserv were sent an email link to a brief, anonymous electronic survey. Respondents were asked their position in the residency, the name of their department, and questions regarding the presence and types of PS evaluative data and PE education they provide.
RESULTS: We obtained 168 responses from 139 individual residencies, representing 72% of all categorical EM residencies. This survey found that only 27% of responding residencies provide PS data to their residents. Of those programs, 61% offer simulation scores, 39% provide third-party attending data on cases with resident participation, 37% provide third-party acquired data specifically about residents and 37% provide internally acquired quantitative data. Only 35% of residencies reported having any organized PE curricula. Of the programs that provide an organized PE curriculum, most offer multiple modalities; 96% provide didactic lectures, 49% small group sessions, 47% simulation sessions and 27% specifically use standardized patient encounters in their simulation sessions.
CONCLUSION: The majority of categorical EM residencies do not provide either PS data or any organized PE curriculum. Those that do use a heterogeneous set of data collection modalities and educational techniques. American Osteopathic Association and Accreditation Council for Graduate Medical Education residencies show no significant differences in their resident PS data provision or formal curricula. Further work is needed to improve education given the high stakes of PS scores in the emergency physician\u27s career
Modeling the strategic trading of electricity assets
We analyze how strategic asset trading can be used to gain competitive advantage. In the case of electricity markets, companies seek to improve the value of their generating portfolios by acquiring, or selling, power plants. Accordingly, we derive the basic determinants of plant value, explaining how a particular productive asset may have different values for different firms. From this, we develop an evolutionary model to understand how market structure interacts with strategic asset trading to increase the competitive advantage of firms, and furthermore, how this depends upon the actual price-setting microstructure in the wholesale market itselfCompetitive advantage, computational learning, auctions, asset trading, simulation, electricity markets
Mission Capabilities of Ion Engines. Phase II
Payloads and mission times were calculated for space vehicles propelled by ion rockets using nuclear power supplies having specific weights from 10 t o 50 lb/kw. Included in the study were five missions: low-altitude lunar satellite, low-altitude Venus satellite, solar probe, Saturn probe, and a Jupiter satellite with a circular orbit at the altitude of Jupiter's fourth moon. The variation of payload with the ration of power supply weight to gross weight was studied and the optimum power levels thereby determined. The ion rocket payload capabilities were compared with those of high-thrust vehicles using hydrogen-oxygen rockets and tungsten-core nuclear rockets; in addition the performance of high- and low-thrust systems staged in combination has been investigated. Launch vehicles considered in this study were the Atlas-Centaur, the Saturn C-1, and the Saturn C-5
Reducing Penguin Pollution
The most common decay used for measuring 2beta_s, the phase of Bs-Bsbar
mixing, is Bs -> J/psi phi. This decay is dominated by the colour-suppressed
tree diagram, but there are other contributions due to gluonic and electroweak
penguin diagrams. These are often referred to as "penguin pollution" (PP)
because their inclusion in the amplitude leads to a theoretical error in the
extraction of 2beta_s from the data. In the standard model (SM), it is
estimated that the PP is negligible, but there is some uncertainty as to its
exact size. Now, phi_s^{c\bar{c}s} (the measured value of 2beta_s) is small, in
agreement with the SM, but still has significant experimental errors. When
these are reduced, if one hopes to be able to see clear evidence of new physics
(NP), it is crucial to have the theoretical error under control. In this paper,
we show that, using a modification of the angular analysis currently used to
measure phi_s^{c\bar{c}s} in Bs -> J/psi phi, one can reduce the theoretical
error due to PP. Theoretical input is still required, but it is much more
modest than entirely neglecting the PP. If phi_s^{c\bar{c}s} differs from the
SM prediction, this points to NP in the mixing. There is also enough
information to test for NP in the decay. This method can be applied to all
Bs/Bsbar -> V1 V2 decays.Comment: 17 pages, latex, extensive discussion of theoretical error added,
reference added. Further revision: even more detailed discussion of
theoretical error added, as well as an explanation of why the NP strong phase
is negligibl
A comparison of benthic macroinvertebrate assemblages between perennial and intermittent headwater streams of the Mattole River in northern California, USA
Intermittent streams are common throughout the world and comprise 60% or more of total river lengths in the conterminous United States. Despite their prevalence, intermittent streams are understudied, particularly first-order headwater streams, which are vital for maintaining the function, health and biotic diversity of river networks. In June 2016, I sampled five intermittent and five perennial headwater streams in the Mattole River watershed in northwestern coastal California, USA, to compare benthic macroinvertebrate (BMI) assemblages between intermittent and perennial streams. BMI samples were collected using a 500µm mesh D-net at eight randomly located riffles along a 150-m reach, and then composited, on each of the 10 streams. Chemical (e.g. pH, dissolved oxygen, temperature, and flow) and physical (e.g. bed substrate composition, bank-full width, and slope) data were measured at each stream reach. BMI samples were identified using Standard Taxonomic Effort (STE). Major difference in assemblages among stream type were not detected except for a few individual taxa, families, and orders. Observed differences likely resulting from taxonomic differences in life history timing. The proportion of shredders was detectably lower in intermittent streams. Further studies with a temporal factor are needed to validate these findings
- …