1,291 research outputs found
Energy-balance climate models
An introductory survey of the global energy balance climate models is presented with an emphasis on analytical results. A sequence of increasingly complicated models involving ice cap and radiative feedback processes are solved and the solutions and parameter sensitivities are studied. The model parameterizations are examined critically in light of many current uncertainties. A simple seasonal model is used to study the effects of changes in orbital elements on the temperature field. A linear stability theorem and a complete nonlinear stability analysis for the models are developed. Analytical solutions are also obtained for the linearized models driven by stochastic forcing elements. In this context the relation between natural fluctuation statistics and climate sensitivity is stressed
PEACH PRICES IN CALIFORNIA IN THE PRESENCE OF TECHNOLOGICAL CHANGE IN THE AGRICULTURAL PESTICIDE INDUSTRY
The potentially adverse effects of pesticides in wide use are causing concern to grow in the agricultural community. Minimizing the risks to human health and the environment created by agricultural pesticides has become a very important issue. The United States Environmental Protection Agency (EPA) has set a high priority on registering safer pesticides. According to the EPA, more than 1 billion pounds of active pesticide ingredients are used in the United States each year. Americans are exposed to pesticides every day through food consumption, cleaning products, and home and work environments. The agricultural pesticide industry has experienced an influx of changes during the past decade. Two of the primary changes affecting the pesticide industry are the introduction of new technology and EPA regulatory changes. On the regulatory front, the EPA requires manufacturers to register and test pesticides before they appear on the market. By 2006, the EPA will review old pesticides to ensure that they meet new safety requirements. These regulatory initiatives have contributed to the industry drive to develop safer and more "environmentally friendly" products for use in agricultural pest control. Technological changes consist of the introduction of new pesticides that are considered to be safer for both humans and the environment. As new technologies and regulatory initiatives are undertaken to ensure an improvement in both the safety of human health and the environment, one must consider how these changes may affect consumers. Specifically, an analysis should be conducted to determine whether or not the technological and regulatory changes have an effect on consumer prices. The recent developments in the agricultural pesticide industry provide several reasons to believe structural change has been occurring in economic relationships that determine peach prices in California. Therefore, we use a vector autoregressive (VAR) model to forecast peach prices by allowing parameters to vary with time. VAR models differ from standard econometric analyses of structural relationships in that they do not apply the usual exclusion restrictions to specify a priori which variables appear in which equations. Instead, a set of distributed lag equations is used to model each variable as a function of other variables in the structural system (Bessler, 1984). The objective of this paper is to forecast peach prices and evaluate dynamic relationships in the peach industry in the presence of technological and regulatory change. A VAR model that explicitly recognizes structural change will be used to forecast peach prices in California. Changes in dynamic relationships between peach prices and relevant economic variables will be considered.Demand and Price Analysis,
The Wisconsin H-Alpha Mapper Northern Sky Survey
The Wisconsin H-Alpha Mapper (WHAM) has surveyed the distribution and
kinematics of ionized gas in the Galaxy above declination -30 degrees. The WHAM
Northern Sky Survey (WHAM-NSS) has an angular resolution of one degree and
provides the first absolutely-calibrated, kinematically-resolved map of the
H-Alpha emission from the Warm Ionized Medium (WIM) within ~ +/-100 km/s of the
Local Standard of Rest. Leveraging WHAM's 12 km/s spectral resolution, we have
modeled and removed atmospheric emission and zodiacal absorption features from
each of the 37,565 spectra. The resulting H-Alpha profiles reveal ionized gas
detected in nearly every direction on the sky with a sensitivity of 0.15 R (3
sigma). Complex distributions of ionized gas are revealed in the nearby spiral
arms up to 1-2 kpc away from the Galactic plane. Toward the inner Galaxy, the
WHAM-NSS provides information about the WIM out to the tangent point down to a
few degrees from the plane. Ionized gas is also detected toward many
intermediate velocity clouds at high latitudes. Several new H II regions are
revealed around early B-stars and evolved stellar cores (sdB/O). This work
presents the details of the instrument, the survey, and the data reduction
techniques. The WHAM-NSS is also presented and analyzed for its gross
properties. Finally, some general conclusions are presented about the nature of
the WIM as revealed by the WHAM-NSS.Comment: 42 pages, 14 figures (Fig 6-9 & 14 are full color); accepted for
publication in 2003, ApJ, 149; Original quality figures (as well as data for
the survey) are available at http://www.astro.wisc.edu/wham
Design, analysis and test verification of advanced encapsulation systems, phase 2 program results
Optical, electrical isolation, thermal structural, structural deflection, and thermal tests are reported. The utility of the optical, series capacitance, and structural deflection models was verified
P2P lending and outside entrepreneurial finance
Later stage, unlisted SMEs are typically too old to attract equity crowdfunding, one of the two novel sources of outside entrepreneurial finance. The other source is peer-to-peer (P2P) business lending – sometimes called marketplace lending or debt crowdfunding – where unlisted SMEs raise medium term loans from a combination of the crowd of small investors and financial institutions via internet portals. The institutions benefit from the collective wisdom of the crowd while institutional investments reduce information asymmetries for other investors and may lead to herding by the crowd. This paper studies the incremental decision to choose P2P over bank debt by means of probit and logit regressions. It establishes that firms with relatively high credit ratings, smaller assets, lower levels of prior capital expenditures, and low leverage ratios are more likely to raise P2P rather than bank debt. The conclusion is that P2P debt plays a unique role in accommodating the outside entrepreneurial capital needs of these SMEs wanting medium term funding. The empirical work employs a sample 1,249 small, private SMEs that received P2P loans with maturities of up to five years 2013–2015 from Funding Circle, the leading UK P2P business lender
Precision Measurement of the Radiative Decay of the Free Neutron
The standard model predicts that, in addition to a proton, an electron, and
an antineutrino, a continuous spectrum of photons is emitted in the
decay of the free neutron. We report on the RDK II experiment which measured
the photon spectrum using two different detector arrays. An annular array of
bismuth germanium oxide scintillators detected photons from 14 to 782~keV. The
spectral shape was consistent with theory, and we determined a branching ratio
of 0.00335 0.00005 [stat] 0.00015 [syst]. A second detector array
of large area avalanche photodiodes directly detected photons from 0.4 to
14~keV. For this array, the spectral shape was consistent with theory, and the
branching ratio was determined to be 0.00582 0.00023 [stat] 0.00062
[syst]. We report the first precision test of the shape of the photon energy
spectrum from neutron radiative decay and a substantially improved
determination of the branching ratio over a broad range of photon energies
The Appearance and Disappearance of Ship Tracks on Large Spatial Scales
The 1-km advanced very high resolution radiometer observations from the morning, NOAA-12, and afternoon,
NOAA-11, satellite passes over the coast of California during June 1994 are used to determine the altitudes,
visible optical depths, and cloud droplet effective radii for low-level clouds. Comparisons are made between
the properties of clouds within 50 km of ship tracks and those farther than 200 km from the tracks in order to
deduce the conditions that are conducive to the appearance of ship tracks in satellite images. The results indicate
that the low-level clouds must be sufficiently close to the surface for ship tracks to form. Ship tracks rarely
appear in low-level clouds having altitudes greater than 1 km. The distributions of visible optical depths and
cloud droplet effective radii for ambient clouds in which ship tracks are embedded are the same as those for
clouds without ship tracks. Cloud droplet sizes and liquid water paths for low-level clouds do not constrain the
appearance of ship tracks in the imagery. The sensitivity of ship tracks to cloud altitude appears to explain why
the majority of ship tracks observed from satellites off the coast of California are found south of 358N. A small
rise in the height of low-level clouds appears to explain why numerous ship tracks appeared on one day in a
particular region but disappeared on the next, even though the altitudes of the low-level clouds were generally
less than 1 km and the cloud cover was the same for both days. In addition, ship tracks are frequent when lowlevel
clouds at altitudes below 1 km are extensive and completely cover large areas. The frequency of imagery
pixels overcast by clouds with altitudes below 1 km is greater in the morning than in the afternoon and explains
why more ship tracks are observed in the morning than in the afternoon. If the occurrence of ship tracks in
satellite imagery data depends on the coupling of the clouds to the underlying boundary layer, then cloud-top
altitude and the area of complete cloud cover by low-level clouds may be useful indices for this coupling.This work was supported in part by the Office of Naval Research and by the National Science Foundation through the Center for Clouds, Chemistry and Climate at the Scripps Institution of Oceanography, an NSF Science and Technology Center
The political process of constructing a sustainable London Olympics sports development legacy
This study attempts to develop a research agenda for understanding the process of constructing a sustainable Olympic sports development legacy. The research uses a social constructivist perspective to examine the link between the 2012 London Olympic Games and sustainable sports development. The first part of the paper provides justification for the study of sport policy processes using a constructivist lens. This is followed by a section which critically unpacks sustainable sports development drawing on Mosse’s (1998) ideas of process-oriented research and Searle’s conceptualisation of the construction of social reality. Searle’s (1995) concepts of the assignment of function, collective intentionality, collective rules, and human capacity to cope with the environment are considered in relation to the events and discourses emerging from the legacy vision(s) associated with the 2012 London Olympic Games. The paper concludes by proposing a framework for engaging in process oriented research and highlights key elements, research questions, and methodological issues. The proposed constructivist approach can be used to inform policy, practice, and research on sustainable Olympic sports development legacy
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