Internet firms charge a wide range of prices for homogeneous products, and high-priced firms remain high-priced and low-priced firms remain low-priced over long periods. One explanation is that ...high-price firms are charging a premium for superior service. An alternative, price-dispersion explanation is that firms vary the prices for informed and uniformed consumers (Salop and Stiglitz, 1977) or serious shoppers and others (Wilde and Schwartz, 1979). The pricing pattern for a digital camera and a flatbed scanner is consistent with the price-dispersion model and inconsistent with the service-premium hypothesis.
The dust that formed our planet, and the elements necessary for life to evolve here were created by stars. It is common for supernova to receive credit for our life on Earth, and there is no doubt ...they played a crucial role, however, theirs is not the only meaningful contribution. Recent observations have shown that Asymptotic Giant Branch (AGB) stars are responsible for returning substantial amounts of enriched material to their surrounding environments. AGB stars are highly-evolved low-to-intermediate mass stars that undergo significant mass loss as they near the end of their lives. The majority of stars that have died in our Universe have done so following the AGB phase (Hofner & Oloffson 2018), indicating these stars have great influence over galactic enrichment and the creation of new solar systems and potential life. Mira variables are AGB stars that undergo regular pulsation every 200–500 days. These pulsations, combined with their cool atmospheres (2000–3000 K), make Mira variables prolific molecule and dust factories. Studying the circumstellar environments surrounding Mira variables provides astrophysicists with the opportunity to observe the processes that created the building blocks of our solar system.The characteristic pulsations of Mira variables make their circumstellar environments quite dynamic; to study how different atmospheric layers respond to the pulsation we need multiple observations across the entire pulsational period of the star. Observing Mira atmospheres at mid-infrared wavelengths provides access to the molecule and dust forming regions; these observations are best done with space-based instruments to avoid affects of telluric absorption. The Mira variables in this work were all observed at least twice with the Spitzer Space Telescope. High-resolution spectra (R ~600) were taken approximately once a month with the Infrared Spectrograph (IRS) (Houck et al 2004); the stars in this study are all bright in the infrared, and thus the exposures were kept brief to prevent saturation of the detector. The resulting spectra have high signal-to-noise ratios that display both gaseous and solid-state (dust) features.The full Spitzer data set contains nearly 100 spectra for 25 stars spanning all three chemical subclasses. This dissertation focuses on analyzing five ro-vibrational Q-branch bandheads of CO2 identified in the spectra of the oxygen-rich Miras (M-types,) and a previously un-observed feature at 17.62 micron that was observed across all three chemical subclasses. We have tentatively identified this new feature as Fe I. The CO2 lines were analyzed using the publicly available code, RADEX (van der Tak et al. 2007), which uses a molecular data file that includes collisions to solve the radiative transfer; RADEX also has the capability of solving the radiative transfer under non-local thermodynamic equilibrium (NLTE) conditions, which is important for Mira atmosphere, because we do not know how the pulsating atmosphere affects the CO2 gas. Files for many molecules ready for calculations are included as part of the Leiden Atomic and Molecular Database (LAMDA), however, the majority of these files were built for modeling pure rotational spectra in the radio. We built a custom molecular file of ro-vibrational transitions of CO2 that includes over 800 radiative transitions, approximately 20,000 collisions with H2, and spans temperatures from 100–1000 K. We used RADEX to calculate synthetic spectra that match the observed CO2 Q-branch bandheads. The synthetic spectra allow us to determine atmospheric conditions of the CO2 gas like column density and kinetic temperature. For the new feature at 17.62 micron we fit every observation with Gaussian line profile to track its behavior with phase; this line has a completely different character than other features, and is extremely narrow, and bright. This behavior may be caused by fluorescence, and we explored several possible pumping mechanisms.The results of the RADEX calculations show that CO2 is highly extended throughout the M-type atmospheres. The kinetic temperatures also indicate that the CO2 gas is much cooler in regions close to the star than radiative equilibrium conditions would predict. This suggests that CO2 is in a previously theorized "refrigeration zone'' that requires a break from radiative equilibrium, and allows dust condensation within a stellar radii (Willson 2000). The behavior of the CO2 lines shows that the M-types with longer periods are behaving differently than those with shorter periods. This behavior is also seen with the 17.62 micron feature; the line strength are consistently greater across all three chemical subclasses in the Miras with periods over 300 days. These results indicate that Miras with longer periods perturb their surrounding atmospheres differently than Miras with shorter periods.
Using detailed data on conflict-related incidents in Indonesia, we exploit seasonal variation in the relationship between rainfall and agricultural production to study the mechanism linking climate ...change and conflict. Furthermore, we ask whether irrigation and dam infrastructure help mitigate this link. We find that wet-season rainfall decreases production while rainfall during the dry season is beneficial for production. If agriculture is the mechanism through which climate change affects conflict, then we should expect the opposite effect on conflict, but with one-year lag. Our results show that, as expected, dry-season rainfall decreases conflict in Indonesia and in agricultural regions like Java, while wet-season rainfall increases conflict. In the latter, we find that irrigation increases conflict instead of reducing it. For Indonesia, irrigation reduces the effect of conflict during the dry season and amplifies it during the wet season. A plausible explanation is that the irrigation network is not well adapted to agriculture necessities which could generate civil unrest when a weather shock occurs. A policy that aim to reducing the impact of climate change on civil conflict should consider these drawbacks.
The European Union (EU) has raised concerns about the use of sinks and an Emissions Intensity system in Canada and has decided not to allow sinks to be included in its trading system. Despite this ...restriction, the EU has shown interest in expanding its trading system to include other countries such as Japan and Canada, while Canada hopes to use sinks and a domestic trading system with an Emissions Intensity regulatory mechanism to meet its Kyoto GHG commitments. In this paper, we briefly discuss some of the implications of the Emissions Intensity regulations scheme, and then develop a simple credit model with trade to illustrate the effect of a trade ban put in place by the EU, first, when it is fully binding and second, when there are countries that can act to arbitrage both markets (e.g., Japan). We also look at the possibilities of using harmonization frameworks to control trade, as well as using a form of discounting with respect to Canadian credits. We show that it is highly unlikely that a trade barrier will increase the use of emission reduction (and decreased use of sinks), and that, particularly in the likely case that Canada will import credits, trade barriers will actually increase the use of sinks. We do find, however, that the use of discounting could serve as a possible policy alternative to increase the use of EU reductions, while decreasing the quantity of Canadian sink credits.
L'Union européenne (UE) s'inquiète du recours aux puits de carbone et de la mise en place d'un système de cibles d'intensité des émissions de carbone au Canada et a décidé d'interdire les puits de carbone dans son système d'échange de droits d'émissions. Malgré cette interdiction, l'UE s'est dite intéressée àélargir son système d'échange pour inclure d'autres pays tels que le Japon et le Canada, tandis que le Canada espère utiliser les puits de carbone et un système d'échange national assorti d'un mécanisme réglementaire sur l'intensité des émissions afin de respecter ses engagements quant aux émissions de gaz à effet de serre (GES) du Protocole de Kyoto. Dans le présent article, nous avons discuté brièvement de certaines répercussions des règlements sur l'intensité des émissions, et avons mis au point un modèle de crédit simple avec échanges pour illustrer les effets d'une interdiction des échanges par l'UE, tout d'abord lorsque l'interdiction est obligatoire et ensuite, lorsque des pays (p. ex. le Japon) peuvent échanger sur les deux marchés. Nous avons également examiné les possibilités d'utiliser des cadres d'harmonisation pour contrôler les échanges, de même qu'une façon d'escompter les crédits canadiens. Nous avons montré qu'il est fort improbable qu'un obstacle aux échanges fasse accroître le recours à la réduction des émissions (et diminuer le recours aux puits), et que, particulièrement dans le cas probable où le Canada importera des crédits, les obstacles aux échanges augmenteront en fait l'utilisation des puits. Nous croyons cependant que le recours à l'escompte pourrait s'avérer une solution pour augmenter le recours aux réductions de l'UE, tout en diminuant la quantité de crédits canadiens accordés pour des puits de carbone.
Climate change is predicted to increase the number and severity of extreme rainfall events, especially in Sub-Saharan Africa. In response, development agencies are encouraging the adoption of ...`climate-smart' agricultural techniques, such as conservation agriculture (CA). However, little rigorous evidence exists to demonstrates the effect of CA on production or climate resilience, and what evidence there is, is hampered by selection bias. Using panel data from Zimbabwe, we test how CA performs during extreme rainfall events - both shortfalls and surpluses. We control for the endogenous adoption decision and find that while CA has little, or if anything, a negative effect on yields during periods of average rainfall, it is effective in mitigating the negative impacts of rainfall shocks. Households that practice CA tend to receive higher yields compared to households using conventional methods in years of both low and high rainfall. We conclude that the lower yields during normal rainfall seasons may be a proximate factor in low uptake of CA. Policy should focus promotion of CA on these climate resiliency benefits.
Acknowledgement :
Cet article examine le lien qui existe entre le fédéralisme, la recherche d'un partage de la rente et la pratique de la resquille. En utilisant les données fournies par l'industrie laitière ...canadienne, nous testons quatre hypothèses concernant les causes déterminantes des dépenses qu'entraîne la recherche d'un partage de la rente et le rôle de la resquille. Nous constatons premièrement que les provinces ne coopèrent pas entre elles lorsqu'il s'agit de faire pression sur le gouvernement pour obtenir une protection commerciale. Deuxièmement, nous découvrons que certaines provinces profitent des dépenses faites par les plus grandes provinces (qui sont plus influentes) pour la recherche d'un partage de la rente. Troisièmement, le coût de la recherche d'un partage de la rente s'accroît lorsque le gouvernement fédéral est obligé de prendre une décision quant à l'avenir des politiques protectionnistes. Quatrièmement, les changements institutionnels dûs au GATT ont augmenté le coût de la resquille pour maintenir les politiques protectionnistes. /// This paper examines the link between federalism, rent-seeking and free-riding behaviour. Using data from the Canadian dairy industry, we test four hypotheses of the determinants of rent-seeking expenditure and the role of free-riding. First, we find that provinces do not cooperate with each other when lobbying the federal government for trade protection. Second, some provinces are found to free ride on the rent-seeking expenditure of the larger (more influential) provinces. Third, the cost of rent-seeking increases when the federal government is forced to make a decision regarding the future of the protectionist policies. Fourth, institutional changes under the 1994 GATT raised the rent-seeking cost of maintaining protectionist policies.
The challenge for any trade agreement is to be adaptable enough to enable countries to address legitimate non-trade concerns (NTC) while being restrictive enough to limit harm to other countries and ...to assist the creation of free international markets. In this paper, we focus on how environmental NTC have been addressed in agricultural policy in the USA and the European Union (EU) and the resulting implications for trade agreements. For example, programmes in the USA discourage production on environmentally sensitive land, while the EU encourages extensive production. While these and other differences will affect production and trade, the different approaches to agri-environmental policy affect the degree to which the two regions can use agri-environmental policy to offset commodity payments. This difference in flexibility will, in turn, affect how easily the two regions can accept a trade agreement that mandates greater reductions in trade-distorting price supports.
The United States and Canada are similar in many ways, yet they have taken different approaches to agricultural policy. This paper discusses what affect the different constitutional arrangements have ...had on the development of agricultural policy. Constitutions can affect the policy bargaining process in several ways: they determine who has access to the bargaining process, what is the legal set of policy options and what is the admissible coalition. The two countries' Constitutions differ in where regions have access to the bargaining process, the use of the courts and the size of the admissible coalition. These differences have led to divergent policies, which are evidenced by the response to the recent drop in commodity prices.
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