Progress in Modeling Very Low Mass Stars, Brown Dwarfs, and Planetary Mass Objects

We review recent advancements in modeling the stellar to substellar transition. The revised molecular opacities, solar oxygen abundances and cloud models allow to reproduce the photometric and spectroscopic properties of this transition to a degree never achieved before, but problems remain in the important M-L transition characteristic of the effective temperature range of characterizable exoplanets. We discuss of the validity of these classical models. We also present new preliminary global Radiation HydroDynamical M dwarfs simulations.Comment: Submitted to Mem. S. A. It. Supp

Uncertainties of Synthetic Integrated Colors as Age Indicators

We investigate the uncertainties in the synthetic integrated colors of simple stellar populations. Three types of uncertainties are from the stellar models, the population synthesis techniques, and from the spectral libraries. Despite some skepticism, synthetic colors appear to be reliable age indicators when used for select age ranges. Rest-frame optical colors are good age indicators at ages 2 -- 7Gyr. At ages sufficiently large to produce hot HB stars, the UV-to-optical colors provide an alternative means for measuring ages. This UV technique may break the age-metallicity degeneracy because it separates old populations from young ones even in the lack of metallicity information. One can use such techniques on extragalactic globular clusters and perhaps even for high redshift galaxies that are passively evolving to study galaxy evolution history.Comment: 38 pages, 21 figures, LaTex, 2003, ApJ, 582 (Jan 1), in pres

The Chemical Composition of an Extrasolar Minor Planet

We report the relative abundances of 17 elements in the atmosphere of the white dwarf star GD 362, material that, very probably, was contained previously in a large asteroid or asteroids with composition similar to the Earth/Moon system. The asteroid may have once been part of a larger parent body not unlike one of the terrestrial planets of our solar system.Comment: ApJ, in pres

Stellar Envelope Convection calibrated by Radiation Hydrodynamics Simulations: Influence on Globular Clusters Isochrones

One of the largest sources of uncertainty in the computation of globular cluster isochrones and hence in the age determination of globular clusters is the lack of a rigorous description of convection. Therefore, we calibrated the superadiabatic temperature gradient in the envelope of metal-poor low-mass stars according to the results from a new grid of 2D hydrodynamical models, which cover the Main Sequence and the lower Red Giant Branch of globular cluster stars. In practice, we still use for computing the evolutionary stellar models the traditional mixing length formalism, but we fix the mixing length parameter in order to reproduce the run of the entropy of the deeper adiabatic region of the stellar envelopes with effective temperature and gravity as obtained from the hydro-models. The detailed behaviour of the calibrated mixing length depends in a non-trivial way on the effective temperature, gravity and metallicity of the star. Nevertheless, the resulting isochrones for the relevant age range of galactic globular clusters have only small differences with respect to isochrones computed adopting a constant solar calibrated value of the mixing length. Accordingly, the age of globular clusters is reduced by 0.2 Gyr at most.Comment: 9 pages, 3 figures Accepted for publication in ApJ Letter

Conflicts of Law (1989)

Conflicts of law occur when foreign elements appear in a lawsuit. Nonresident litigants, incidents in sister states or foreign countries, and lawsuits from other jurisdictions represent foreign elements that may create problems in judicial jurisdiction, choice of law, or recognition of foreign judgments, respectively. This Article reviews Texas conflicts of law during the Survey period from late 1987 through 1988. The survey includes cases from Texas state and federal courts. Excluded are cases involving federal state conflicts, criminal law, intrastate matters such as subject matter jurisdiction and venue, and conflicts in time, such as the applicability of prior or subsequent law within a state. During the Survey period, the Texas Supreme Court effected no significant changes or additions to jurisdictional jurisprudence, but the Northern District of Texas did craft a rule for personal jurisdiction in federal question cases when nationwide service of process is authorized. Cases decided during the Survey period also exhibited both the use of rule 108 as a substitute for the Texas long-arm statute and the difficulty in imputing jurisdictional contacts between parent and subsidiary corporations. Choice of law highlights include a controversial rejection of a Florida noncompetition agreement, as well as the United States Supreme Court\u27s sequel to a 1985 opinion on legislative jurisdiction. Foreign judgments offered three noteworthy cases but no developments

Conflict of Laws (1988)

Conflicts of law occur when foreign elements appear in a lawsuit. Nonresident litigants, incidents in sister states or foreign countries, and lawsuits from other jurisdictions represent foreign elements that may create problems in judicial jurisdiction, choice of law, or recognition of foreign judgments, respectively. This Article reviews Texas conflicts of law during the Survey period from late 1986 through 1987. The survey includes cases from Texas state and federal courts and non-Texas cases affecting Texas practice. Excluded are cases involving federal/state conflicts, criminal law, intrastate matters such as subject matter jurisdiction and venue, except when they relate to the personal jurisdiction inquiry, and conflicts in time, such as the applicability of prior or subsequent law within a state. During the Survey period, the Texas Supreme Court decided an important case finding jurisdiction based on contacts related to the cause of action. During the same period, the United States Supreme Court decided a case, which, although based on varying rationales, was the first unanimous decision finding a lack of personal jurisdiction since International Shoe Co. v. Washington. Choice of law highlights include Texas\u27s enactment of a new statute governing contractual choice of law and Texas courts\u27 improvement in their application of the most significant relationship test from the Restatement (Second) of Conflict of Laws. Foreign judgments\u27 significant development was the declared unconstitutionality of the Uniform Enforcement of Foreign Judgments Act

Conflict of Laws (1988)

Conflicts of law occur when foreign elements appear in a lawsuit. Nonresident litigants, incidents in sister states or foreign countries, and lawsuits from other jurisdictions represent foreign elements that may create problems in judicial jurisdiction, choice of law, or recognition of foreign judgments, respectively. This Article reviews Texas conflicts of law during the Survey period from late 1986 through 1987. The survey includes cases from Texas state and federal courts and non-Texas cases affecting Texas practice. Excluded are cases involving federal/state conflicts, criminal law, intrastate matters such as subject matter jurisdiction and venue, except when they relate to the personal jurisdiction inquiry, and conflicts in time, such as the applicability of prior or subsequent law within a state. During the Survey period, the Texas Supreme Court decided an important case finding jurisdiction based on contacts related to the cause of action. During the same period, the United States Supreme Court decided a case, which, although based on varying rationales, was the first unanimous decision finding a lack of personal jurisdiction since International Shoe Co. v. Washington. Choice of law highlights include Texas\u27s enactment of a new statute governing contractual choice of law and Texas courts\u27 improvement in their application of the most significant relationship test from the Restatement (Second) of Conflict of Laws. Foreign judgments\u27 significant development was the declared unconstitutionality of the Uniform Enforcement of Foreign Judgments Act