“The Past Is Not Prologue”Educational Achievements of Young Adults

As global competition intensifies; college education has become a necessary tool for young adults to succeed. In this study, a mixed method approach was used (the NLSY survey, supplemented with qualitative interviews of seven education professionals) to identify the supportive resources needed by young adults to overcome the risks they faced as they aspired to complete high school and actualized their college aspirations. High school experiences and aspirations did not hinder youth from their later educational achievements. Rather, it was the social and cultural resources available in their post high school lives that mattered in actualizing their college aspirations. That the support available later in their lives as young adults were the most influential in their educational accomplishments supported the predictions of social-capital theories in shaping flexible (Chicago School) academic self-concepts of youth and contributed to the sociology of higher education. While contributing to the scholarship on higher education, the research also underscored the need for the continued support needed by young adults as they pursue their educational goals

Self-Gravitating Phase Transitions: Point Particles, Black Holes and Strings

We compute the quantum string entropy S_s(m,j) of the microscopic string states of mass m and spin j in two physically relevant backgrounds: Kerr (rotating) black holes and de Sitter (dS) space-time. We find a new formula for the quantum gravitational entropy S_{sem} (M, J), as a function of the usual Bekenstein-Hawking entropy S_{sem}^(0)(M, J). We compute the quantum string emission by a black hole in de Sitter space-time (bhdS). In all these cases: (i) strings with the highest spin, and (ii) in dS space-time, (iii) quantum rotating black holes, (iv) quantum dS regime, (v) late bhdS evaporation, we find a new gravitational phase transition with a common distinctive universal feature: A square root branch point singularity in any space-time dimensions. This is the same behavior as for the thermal self-gravitating gas of point particles (de Vega-Sanchez transition), thus describing a new universality class.Comment: Invited lecture at `Statistical Mechanics of Non-Extensive Systems', Observatoire de Paris, 24-25 October 2005, to be published in a Special issue of `Les Comptes rendus de l'Academie des sciences', Elsevie

Trade policy and integration among firms producing complementary products

This paper studies the effects on insurance premiums and consumer welfare when commissions to insurance agencies exist and are used strategically to sell insurance policies. The opportunistic behavior of agency insurers that sell the policy paying the highest commission is considered. Different market structures are considered, namely: a duopoly of insurers that compete in commissions (insurer competition), collusion among insurers with agency insurers remaining independent (horizontal collusion or insurer monopoly) and collusion between insurers and agency insurers (vertical integration or exclusive agents). We find that insurer competition and vertical integration trigger higher premiums than horizontal collusion with independent agencies. Furthermore, we argue that the optimal commission from the consumer viewpoint may be greater than the commission offered under any of the above three market structures.

Tariff protection and trade agreements

This paper studies the optimal tariff rates on goods imported from the rest of the world when a commercial club accepts a new partner. It shows that when a new member is accepted into the club, the other members of a free trade agreement have incentives to reduce tariffs on the rest of the world’s goods. However, when the trade agreement is a custom union, the union may have incentives to increase the common external tariff. This happens when the industry of the custom union is small compared to the world industry

Market Foreclosure and Strategic Aspects of Vertical Agreements

This paper reviews the arguments about market foreclosure –as an incentive for vertical agreements between upstream and downstream firms– and its effects on welfare. We consider that downstream firms compete in quantities in the final good market and upstream firms compete in quantities in the intermediate good market. In this context we show that a vertical agreement must not contemplate market foreclosure, that is, upstream firms continue participating in intermediate market. Regarding antitrust policy, we show that even vertical agreements aimed at increasing input price faced by other firms may be positive from the welfare viewpoint.

Hawking Radiation in String Theory and the String Phase of Black Holes

The quantum string emission by Black Holes is computed in the framework of the `string analogue model' (or thermodynamical approach), which is well suited to combine QFT and string theory in curved backgrounds (particulary here, as black holes and strings posses intrinsic thermal features and temperatures). The QFT-Hawking temperature T_H is upper bounded by the string temperature T_S in the black hole background. The black hole emission spectrum is an incomplete gamma function of (T_H - T_S). For T_H << T_S, it yields the QFT-Hawking emission. For T_H \to T_S, it shows highly massive string states dominate the emission and undergo a typical string phase transition to a microscopic `minimal' black hole of mass M_{\min} or radius r_{\min} (inversely proportional to T_S) and string temperature T_S. The semiclassical QFT black hole (of mass M and temperature T_H) and the string black hole (of mass M_{min} and temperature T_S) are mapped one into another by a `Dual' transform which links classical/QFT and quantum string regimes. The string back reaction effect (selfconsistent black hole solution of the semiclassical Einstein equations with mass M_+ (radius r_+) and temperature T_+) is computed. Both, the QFT and string black hole regimes are well defined and bounded: r_{min} leq r_+ \leq r_S, M_{min} \leq M_+ \leq M, T_H \leq T_+ \leq T_S. The string `minimal' black hole has a life time tau_{min} \simeq \frac{k_B c}{G \hbar} T^{-3}_S.Comment: LaTex, 31 pages, no figure

Public Day Care and Female Labor Force Participation: Evidence from Chile

Public day care centers in Chile have increased in 240% between 2005 and 2007. This paper uses this huge increase in public day care supply for infants of poor families to analyze its impact on Female Labor Force Participation. The magnitude of the expansion is used as a quasi-natural experiment, where different geographic areas and income groups were affected differently. Using mean differences I find a positive effect on Labor Force Participation of 2.6-10 percentage points which coincides with previous findings for Chile and the local policy common sense. After control- ling for observable individual and family characteristics I don’t find any significant effect for the eligible mothers. As a robustness check I also use alternative outcome measures like employment and hours of work and I am not able to find a positive statistically significant effect. Therefore, I conclude that it is not possible yet to infer that this policy has had this desired effect.Female Labor Force, Child Care, Fertility and Labor Supply.