Equivalence classes of augmentations and Morse complex sequences of Legendrian knots

Let L be a Legendrian knot in R^3 with the standard contact structure. In [10], a map was constructed from equivalence classes of Morse complex sequences for L, which are combinatorial objects motivated by generating families, to homotopy classes of augmentations of the Legendrian contact homology algebra of L. Moreover, this map was shown to be a surjection. We show that this correspondence is, in fact, a bijection. As a corollary, homotopic augmentations determine the same graded normal ruling of L and have isomorphic linearized contact homology groups. A second corollary states that the count of equivalence classes of Morse complex sequences of a Legendrian knot is a Legendrian isotopy invariant.Comment: 28 pages, 17 figure

Beer Taxes, the Legal Drinking Age, and Youth Motor Vehicle Fatalities

Based on a time series of state cross sections for the period from 1975 through 1981, we find that motor vehicle accident mortality rates of youths ages 15 through 17, 18 through 20, and 21 through 24 are negatively related to the real beer excise tax. We also find that the death rate of 18 through 20 year olds is inversely related to the minimum legal age for the purchase of beer. Simulations suggest that the lives of 1,022 youths between the ages of 18 and 20 would have been saved in a typical year during the sample period if the Federal excise tax rate on beer, which has been fixed in nominal terms since 1951, had been indexed to the rate of inflation since 1951. This represents a 15 percent decline in the number of lives lost in fatal crashes. The simulations also suggest that the lives of 555 youths per year would have been saved if the drinking age had been 21 in all states of the U.S. These figures indicate that, if reductions in youth motor vehicle accident deaths are desired, both a uniform drinking age of 21 and an increase in the Federal excise tax rate on beerare effective policies to accomplish this goal. They also indicate that the tax policy may be more potent than the drinking age policy.

Post Mortem Reputation, Compensatory Gifts and Equal Bequests

The empirical evidence suggests that parents use inter vivos gifts (i.e., transfers of tangible and financial property) to compensate less well off children whereas post mortem bequests are divided equally among siblings. We study a theoretical model assuming, first, that the amounts given is private information, only known to the donor ant the donee, while the amounts bequeathed is public information. Second, we assume that parents care about the reputation that their bequest behavior will leave them after their death. More specifically, this reputation is deteriorating in the difference in amounts inherited. We show that, given these assumptions, the optimal choice of altruistic parents is compensatory gifts and equal bequests.Altruism; bequests; inheritance; gifts; equal division; post mortem reputation; social norm; information.

Who Takes Care of the Children? The Quantity-Quality Model Revisited

We study the Becker and Lewis (1973) quantity-quality model of children adding an explicit child care time constraint for parents. They can purchase day care or take care of the children themselves. Our results are: (i) If there is a combination of purchased and own care, the effect of income on fertility is ambiguous, even if quantity of children is a normal good in the standard sense. This is the Becker and Lewis (1973) result. (ii) If, however, there only is purchased care, the income effect on fertility is positive when quantity is a normal good. (iii) If, on the other hand, there only is own care, there is a different kind of quantity-quality trade-off. The income effect on fertility is positive if quantity is a closer complement than quality to the consumption of goods.Fertility; Child Care; Time Constraint; Quantity-Quality Trade-off

Post Mortem Reputation, Compensatory Gifts and Equal Bequests

The empirical evidence suggests that parents use inter vivos gifts (i.e., transfers of tangible and financial property) to compensate less well off children whereas post mortem bequests are divided equally among siblings. We study a theoretical model assuming, first, that the amounts given is private information, only known to the donor and the donee, while the amounts bequeathed is public information. Second, we assume that parents care about the reputation that their bequest behavior will leave them after their death. More specifically, this reputation is deteriorating in the difference in amounts inherited. We show that, given optimal choice of altruistic parents is compensatory gifts and equal bequests.altruism; bequests; inheritances; gifts; equal division; post mortem reputation; social norm; information

Not All Scientists pay to be Scientists:

A growing body of research on firms’ “open science” strategies rests on the notion that scientists have a strong preference for publishing and that firms are able to extract a wage discount if they allow scientists to publish. Drawing on a survey of 1,400 life scientists about to enter the job market, we suggest an alternative view. First, we show significant heterogeneity in the price scientists assign to the opportunity to publish in firms, and those scientists who seek industry careers have particularly low preferences for publishing. Thus, many job applicants are not willing to accept lower wages for jobs that let them publish and firms pursuing open science strategies may instead have to pay publishing incentives that fulfill both sorting and incentive functions. Second, we show that scientists with higher ability have a higher price of publishing but also expect to be paid higher wages regardless of the publishing regime. Thus, they are not cheaper to hire than other scientists if allowed to publish, but they are more expensive if publishing is restricted. Finally, we show that scientists publish not simply for “peer recognition” but also for more specific reasons, including the opportunity to advance science or to move to higher-paying jobs. Different reasons predict what price a scientist assigns to the opportunity to publish and may also have very different implications for the sustainability of competitive advantages derived from open science strategies.Scientists; publishing; competitive advantage