Capture-zone scaling in island nucleation: phenomenological theory of an example of universal fluctuation behavior

In studies of island nucleation and growth, the distribution of capture zones, essentially proximity cells, can give more insight than island-size distributions. In contrast to the complicated expressions, ad hoc or derived from rate equations, usually used, we find the capture-zone distribution can be described by a simple expression generalizing the Wigner surmise from random matrix theory that accounts for the distribution of spacings in a host of fluctuation phenomena. Furthermore, its single adjustable parameter can be simply related to the critical nucleus of growth models and the substrate dimensionality. We compare with extensive published kinetic Monte Carlo data and limited experimental data. A phenomenological theory sheds light on the result.Comment: 5 pages, 4 figures, originally submitted to Phys. Rev. Lett. on Dec. 15, 2006; revised version v2 tightens and focuses the presentation, emphasizes the importance of universal features of fluctuations, corrects an error for d=1, replaces 2 of the figure

Discharge Patterns of Single Fibers in the Cat's Auditory Nerve

Discharge patterns of single fibers in cat auditory nerve in response to controlled acoustic stimul

Social aspects of confucianism and taoism

This item was digitized by the Internet Archive. Thesis (M.S.)--Boston Universityhttps://archive.org/details/socialaspectsofc00kia

Habitable Climate Scenarios for Proxima Centauri b With a Dynamic Ocean

The nearby exoplanet Proxima Centauri b will be a prime future target for characterization, despite questions about its retention of water. Climate models with static oceans suggest that an Earth-like Proxima b could harbor a small dayside region of surface liquid water at fairly warm temperatures despite its weak instellation. We present the first 3-dimensional climate simulations of Proxima b with a dynamic ocean. We find that an ocean-covered Proxima b could have a much broader area of surface liquid water but at much colder temperatures than previously suggested, due to ocean heat transport and depression of the freezing point by salinity. Elevated greenhouse gas concentrations do not necessarily produce more open ocean area because of possible dynamic regime transitions. For an evolutionary path leading to a highly saline present ocean, Proxima b could conceivably be an inhabited, mostly open ocean planet dominated by halophilic life. For an ocean planet in 3:2 spin-orbit resonance, a permanent tropical waterbelt exists for moderate eccentricity. Simulations of Proxima Centauri b may also be a model for the habitability of planets receiving similar instellation from slightly cooler or warmer stars, e.g., in the TRAPPIST-1, LHS 1140, GJ 273, and GJ 3293 systems.Comment: Submitted to Astrobiology; 38 pages, 12 figures, 5 table

Noise generation by shock-turbulence interaction

October 1970Includes bibliographical references (leaf 10)The noise produced by convection of turbulence through an oblique shock wave has been measured and compared to theoretical predictions by Ribner and Kerrebrock. There is excellent agreement with the theoretical prediction that, for a fixed turbulent input, the downstream noise pressure (divided by the mean pressure), should first increase very rapidly, and then decrease as the normal Mach number of the shock is increased from unity to values of the order of 1.5. This behavior implies that a part of the noise from supersonic jets should behave similarly, with a sharp increase, then a decrease as the nozzle pressure ratio is raised from unity.This Research Carried Out in the Gas Turbine Laboratory, M.I.T., in Cooperation with Lewis Research Center, NASA, under Grant NGL 22-009-38

The protective role of Familism in the lives of Latino Adolescents

Abstract: Familism, a Latino value that promotes loyalty, cohesiveness, and obedience within the family, predicts improved outcomes for Latino adolescents. However, few studies have tested whether familism serves a protective role when adolescents are facing stress. We examined whether familism predicted psychosocial outcomes in the context of stress, and whether familism moderated the relationship between peer discrimination, acculturative stress, and economic stress predicting these outcomes in a sample of 173 Latino adolescents. Familism was associated with fewer depressive symptoms and greater school attachment, but it did not moderate the relationship between any of the stressors and outcomes. Discrimination was associated with greater depressive symptoms, worse school attachment, and greater perceived barriers to college, but socioeconomic stress and acculturation stress did not uniquely predict these outcomes once taking into account discrimination. Thus, although familial culture values lead to improved outcomes in youth, they are unable to counter the detrimental effects of discrimination

Gendered academic adjustment among Asian American adolescents in an emerging immigrant community

Abstract: Research on the academic adjustment of immigrant adolescents has been predominately conducted in large cities among established migration areas. To broaden the field's restricted focus, data from 172 (58% female) Asian American adolescents who reside within a nontraditional or emerging immigrant community in the Southeastern US were used to examine gender differences in academic adjustment as well as school, family, and cultural variables as potential mediators of gender differences found. Results suggest that girls report significantly higher educational goals, intrinsic academic motivation, and utility value of school compared to boys. These gender differences are statistically mediated by ethnic exploration and family processes, most prominently, family respect. School connectedness and perceived discrimination are also associated with academic adjustment at the bivariate level, suggesting that academic success may be best promoted if multiple domains of influence can be targeted. gender | academic adjustment | Asian adolescents | immigrants | immigran

The Initial Mass Function as given by the fragmentation

The dichotomy between a universal mass function (IMF) and a variable IMF which depends on local physical parameters characterises observational and theoretical stellar astronomy. In this contribution the available distributions of probability are briefly reviewed. The physical nature of two of them, gamma variate and lognormal, is then explained once the framework of the fragmentation is introduced. Interpolating techniques are then applied to the sample of the first 10 pc and to the open cluster NGC6649: in both cases lognormal distribution produces the best fit. The three power law function has also been investigated and visual comparison with an artificially generated sample of 100000 stars suggests that the variations in the spectral index are simply due to the small number of stars available in the observational sample. In order to derive the sample of masses, a new formula that allows us to express the mass as a function of the absolute magnitude and (B-V) for MAIN V, GIANTS III and SUPERGIANTS I is derived.Comment: 6 pages 9 figure