The informativeness of on-line advertising

Sending general advertisements with inflationary claims may attract additional visitors with whom an advertiser is poorly matched. This is costly when ads are priced per-click because many visitors (clickers) will not purchase. This renders per-click advertising particularly conducive to the transmission of information via ads. The admissibility of information transmission depends not only on advertiser behaviour, but also upon consumers' interpretation of and trust in ads. In less conducive environments, consumers quickly learn to place little stock in the claims they see advertised. This mechanism undermines the ability of advertisers and consumers to communicate under per-impression or per-sale fee structures. Consumers benefit from increased informativeness, but distortions introduced by the market power given to advertisers imply that society may be better-off with no information transmission taking place.     

ON THE PRICE EFFECTS OF HORIZONTAL MERGERS: A THEORETICAL INTERPRETATION

Horizontal mergers are usually under the scrutiny of antitrust authorities due to their potential undesirable effects on prices and consumer surplus. Ex‐post evidence, however, suggests that these effects do not always take place and even relevant mergers may end up having negligible price effects. The analysis of mergers in the context of non‐localized spatial competition may offer a further interpretation to the ones proposed in the literature: in this framework both positive and zero price effects are possible outcomes of the merger activity.     

Contest architecture

A contest architecture specifies how the contestants are split among several sub-contests whose winners compete against each other (while other players are eliminated). We compare the performance of such dynamic schemes to that of static winner-take-all contests from the point of view of a designer who maximizes either the expected total effort or the expected highest effort. For the case of a linear cost of effort, our main results are: (1) If the designer maximizes expected total effort, the optimal architecture is a single grand static contest. (2) If the designer maximizes the expected highest effort, and if there are sufficiently many competitors, it is optimal to split the competitors in two divisions, and to have a final among the two divisional winners. Finally, if the effort cost functions are convex, the designer may benefit by splitting the contestants into several sub-contests, or by awarding prizes to all finalists.     

Estimation of market power in the presence of firm level inefficiencies

“The quiet life hypothesis” (QLH) by Hicks (1935) argues that, due to management’s subjective cost of reaching optimal profits, firms use their market power to allow inefficient allocation of resources. Increasing competitive pressure is therefore likely to force management to work harder to reach optimal profits. Another hypothesis, which also relates market power to efficiency is “the efficient structure hypothesis” (ESH) by Demsetz (1973). ESH argues that firms with superior efficiencies or technologies have lower costs and therefore higher profits. These firms are assumed to gain larger market shares which lead to higher concentration. Ignoring the efficiency levels of the firms in a market power model might cause both estimation and interpretation problems. Unfortunately, the literature on market power measurement largely ignores this relationship. In the context of a dynamic setting, we estimate the market power of US airlines in two city-pairs by both allowing inefficiencies of the firms and not allowing inefficiencies of the firms. Using industry level cost data, we estimate the cost function parameters and time-varying efficiencies. An instrumental variables version of the square root Kalman filter is used to estimate time-varying conduct parameters.     

山秋油(Anaphalis margaritacea L)挥发成分的研究

山秋油用GC/MS分析鉴定67个成分,占全部精油的97％以上,其中未见文献报道玫瑰呋喃Rosefuran(51.66％)、环氧玫瑰呋喃Rosefuran epoxide(20.07％)为精油的主要化学成分。     

对货代提单的法律思考

签发提单是承运人的法定义务之一。当货代存在的情况下,货代提单与实际承运人签发的提单在流通中常常会发生混乱。应界定货运代理在运输合同中的法律关系,并与货运代理的国际贯例接轨。     

草本植物根系网固土效果研究分析——以紫花苜蓿护坡效果为例

文章以东北林业大学实验林场公路边坡为试验地,通过种植紫花苜蓿,观察其发芽状况、生长速度、覆盖度、抗旱性、抗热性等生态适应性指标,作为评价其护坡效果的重要指标;并用环刀进行现场取样,进行大量含根土的直剪试验,测得含根土体的抗剪强度,与不含根土的抗剪强度进行对比,评判其根系固土能力。通过试验得出紫花苜蓿是一种适合东北地区公路边坡的理想的护坡植物。     

Regulation in the market for education and optimal choice of curriculum

We analyze educational institutions’ incentives to set up demanding or lax curricula in duopolistic markets for education with endogenous enrolment of students. We assume that there is a positive externality from student achievement to the local economy. Comparing the case of regulated tuition fees with an unregulated market, we identify the following inefficiencies: Under regulated tuition fees schools will set up inefficiently lax curricula in an attempt to please low-quality students even if schools internalize some of the externality. On the other hand, unregulated schools set up excessively differentiated curricula in order to relax competition in tuition fees. Deregulation gets more attractive if a larger fraction of the externality is internalized.     

Sparse estimation of dynamic principal components for forecasting high-dimensional time series

We present the sparse estimation of one-sided dynamic principal components (ODPCs) to forecast high-dimensional time series. The forecast can be made directly with the ODPCs or by using them as estimates of the factors in a generalized dynamic factor model. It is shown that a large reduction in the number of parameters estimated for the ODPCs can be achieved without affecting their forecasting performance.     

Mortgage market credit conditions and U.S. Presidential elections

Voters punish incumbent Presidential candidates for contractions in the county-level supply of mortgage credit during market-wide contractions of credit, but do not reward them for expansions in mortgage credit supply in boom times. Our primary focus is the Presidential election of 2008, which followed an unprecedented swing from very generous mortgage underwriting standards to a severe contraction of mortgage credit. Voters responded to the credit crunch by shifting their support away from the Republican Presidential candidate in 2008. That shift was large and particularly pronounced in states that typically vote Republican, and in swing states. Without it McCain would have received half the votes needed in nine crucial swing states to reverse the outcome of the election. We extend our analysis to the Presidential elections from 1996 to 2012 and find that voters only react to contractions, not expansions, of credit, and reactions are similar for Democratic and Republican incumbent parties.