53,832 research outputs found
Fuel subsidies versus market power : is there a countervailing second-best optimum?
Fuel subsidies distort end-use prices below cost, resulting in overconsumption and huge environmental cost. On the other hand, the mark-up over cost due to the exercise of market power results in the social loss of consumer surplus. We open a new line of inquiry into the potential for a market-based solution from these two countervailing forces: can the two offsetting distortions conceivably achieve a second- best optimum? Relying on dynamic panel techniques and gasoline market data for 68 developing countries, we uncover an excessive second-best subsidy offset to market power mark-up on the order of 4.5. Our results indicate that the potential for policy failure strongly exceeds the potential for market failure in our model, and gasoline prices across our sample may not be aligned with vigorous anti-climate change policy
Moral and Philosophic Problems of Modern Medicine: A Collegiate Program for Pre-Medical and Nursing Students
Conformal Solutions Of Duality Invariant 2D Magnetohydrodynamic Turbulence
We consider possible conformal field theory (CFT) descriptions of the various
inertial ranges that exist in duality invariant Magnetohydrodynamics. Such
models arise as effective theories of dyonic plasmas in 3 dimensions in which
all fields are independent of the third coordinate. We find new constraints on
the allowed CFT's compared to those that may describe turbulence in
plasmas of electric charges only. The predictions from CFT concerning
equipartition of energy amongst the electric and magnetic fields are discussed,
and quantities exhibiting universal scaling are derived.Comment: Latex, 8 page
Duality Invariant Magnetohydrodynamics And Dyons
The theory of magnetohydrodynamics is extended to the cases of a plasma of
separate magnetic and electric charges, as well as to a plasma of dyons
respectively. In both these cases the system possesses electric-magnetic
duality symmetry. In the former case we find that because of the existence of
two independent generalized Ohm's law equations, the limit of infinite electric
and magnetic conductivity results in the vanishing of both electric and
magnetic fields, as well as the corresponding currents. In the dyonic case, we
find that the resulting duality-invariant system of equations are equivalent to
those of ordinary MHD, after suitable field redefinitions.Comment: 11 pages, late
The X-ray Properties of Five Galactic Supernova Remnants Detected by the Spitzer GLIMPSE Survey
(Abbreviated) We present a study of the X-ray properties of five Galactic
supernova remnants (SNRs) -- Kes 17 (G304.60.1), G311.50.3, G346.60.2,
CTB 37A (G348.50.1) and G348.50.0 -- that were detected in the infrared
by Reach et al. (2006) in an analysis of data from the Galactic Legacy Infrared
Mid-Plane Survey Extraordinaire (GLIMPSE) that was conducted by the Spitzer
Space Telescope. We present and analyze archival ASCA observations of Kes 17,
G311.50.3 and G346.60.2, archival XMM-Newton observations of Kes 17, CTB
37A and G348.50.0 and an archival Chandra observation of CTB 37A. All of the
SNRs are clearly detected in the X-ray possibly except for G348.50.0. Our
study reveals that the four detected SNRs all feature center-filled X-ray
morphologies and that the observed emission from these sources is thermal in
all cases. We argue that these SNRs should be classified as mixed-morphology
SNRs (MM SNRs): our study strengthens the correlation between MM SNRs and SNRs
interacting with molecular clouds and suggests that the origin of
mixed-morphology SNRs may be due to the interactions between these SNRs and
adjacent clouds. Our ASCA analysis of G311.50.3 reveals for the first time
X-ray emission from this SNR: the X-ray emission is center-filled within the
radio and infrared shells and thermal in nature ( 0.98 keV), thus
motivating its classification as an MM SNR. We find considerable spectral
variations in the properties associated with the plasmas of the other
X-ray-detected SNRs, such as a possible overabundance of magnesium in the
plasma of Kes 17. Finally, we also estimate such properties as electron density
, radiative age and swept-up mass for each of the
four X-ray-detected SNRs.Comment: 78 pages, 26 figures, Astronomical Journal, in pres
Do Childhood Vaccines Have Non-Specific Effects on Mortality
A recent article by Kristensen et al. suggested that measles vaccine and bacille Calmette–Guérin (BCG) vaccine might\ud
reduce mortality beyond what is expected simply from protection against measles and tuberculosis. Previous reviews of the potential effects of childhood vaccines on mortality have not considered methodological features of reviewed studies. Methodological considerations play an especially important role in observational assessments, in which selection factors for vaccination may be difficult to ascertain. We reviewed 782 English language articles on vaccines and childhood mortality and found only a few whose design met the criteria for methodological rigor. The data reviewed suggest that measles vaccine delivers its promised reduction in mortality, but there is insufficient evidence to suggest a mortality benefit above that caused by its effect on measles disease and its sequelae. Our review of the available data in the literature reinforces how difficult answering these considerations has been and how important study design will be in determining the effect of specific vaccines on all-cause mortality.\u
Brief of Law Professors as Amicus Curiae in Support of Respondent
Inventors lacking assurance of a market, or even the right to practice patented inventions, face considerable risk. Those who qualify for patents, in return for disclosure, receive only the assistance of the courts in excluding others from economic exploitation of their inventions. Already subject to many legislative and judicial limitations, patents should not be further subject to the functional equivalent of private inverse condemnation without congressional action
Thermo- and pH-Sensitive Hydrophilic Block Copolymers: Synthesis, Micellization, Gelation, and Application
This dissertation presents the synthesis of a series of thermo- and pH-sensitive hydrophilic block copolymers and the study of their solution behavior in water. By incorporating a small amount of weak acid or base groups into the thermosensitive block(s) of a hydrophilic block copolymer, the LCST of the thermosensitive block(s) can be modified by changing the solution pH. Accordingly, the critical micellization temperature (CMT) and the sol-gel transition temperature (Tsol-gel) of the block copolymer in water can be tuned. Chapter 1 describes the synthesis of thermo- and pH-sensitive poly(methoxydi(ethylene glycol) methacrylate-co-methacrylic acid)-b-PEO-bpoly( methoxydi(ethylene glycol) methacrylate co-methacrylic acid) and the study of sol-gel transitions of its aqueous solutions at various pH values. The CMT of the 0.2 wt% solution and the Tsol-gel of the 12.0 wt% solution of this copolymer can be varied over a large temperature range. By judiciously controlling temperature and pH, multiple sol-gel-sol transitions were realized. Chapter 2 presents a systematic study of pH effect on rheological properties of micellar gels formed from 10.0 wt% aqueous solutions of thermo- and pH-sensitive poly(ethoxydi(ethylene glycol) acrylate-co-acrylic acid)-b-PEO-b-poly(ethoxydi(ethylene glycol) acrylate-co-acrylic acid). With the increase of pH, the sol-gel transition became broader. The plateau moduli (GN) evaluated from frequency sweeps at T/Tsol-gel of 1.025, 1.032, and 1.039 decreased with the increase of pH from 3.00 to 5.40 with the largest drop observed at pH = ~ 4.7. The decrease in GN reflects the reduction of the number of bridging chains. The ionization of carboxylic acid introduced charges onto the thermosensitive blocks and made the polymer more hydrophilic, facilitating the formation of loops and dangling chains. Chapter 3 presents the synthesis of PEO-b-poly(methoxydi(ethylene glycol)methacrylate-co-2-(N-methyl-N-(4-pyridyl)amino)ethyl methacrylate) with the thermosensitive block containing a catalytic 4-N,N-dialkylaminopyridine and the study of the effect of thermo-induced micellization on its activity in the hydrolysis of pnitrophenyl acetate. The CMTs of this copolymer at pH of 7.06 and 7.56 were 40 and 37 °C, respectively. Below CMT, the logarithm of initial hydrolysis rate changed linearly with 1/T. Above CMT, the reaction rate leveled off, which is presumably because it was controlled by mass transport to the core of micelles above CMT
The True Colours of Carbon
Carbon offset projects in developing countries are one of the principal mechanisms designed to reduce greenhouse gas emissions and promote sustainable development yet have critical limitations in both areas. Here we present a framework for categorizing carbon offset projects according to four general approaches to the reduction of greenhouse gas emissions: (1) efficiency ('Brown'); innovation ('Red'), terrestrial sequestration ('Green') or sequestration in aquatic environments ('Blue'). Analysis of the 6109 CDM projects currently in the CDM "pipeline" reveals that 99% are Brown or Red, and only 1% are Green or Blue, yet Green and Blue projects typically offer a far greater range of benefits for ecosystems and society. The analysis concludes that the designers of emissions trading schemes should endorse Green and Blue offset projects as preferred forms of emissions offsetting, and that firms using offsets for compliance purposes be required to declare in public reports the colours of their offset acquisitions. Such reform will help redirect demand in carbon markets toward blue and green offset projects, increasing the sustainability outcomes of carbon offset developments
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