The folding fingerprint of visual cortex reveals the timing of human V1 and V2

Primate neocortex contains over 30 visual areas. Recent techniques such as functional magnetic resonance imaging (fMRI) have successfully identified many of these areas in the human brain, but have been of limited value for revealing the temporal dynamics between adjacent visual areas, a critical component of understanding visual cognition. The voltages recorded at the scalp, electroencephalography (EEG), is a direct measure of neural activity that reflects the summed activity across all brain areas. Identifying the cortical sources that contribute to the EEG is a difficult problem. We developed an anatomically constrained dipole search method that solves the traditional problems by combining fMRI, EEG and many stimuli that activate small cortical regions. The method provides a means to validate the extracted waveforms. Both V1 and V2 waveforms have similar onset latencies as well as dynamics that can explain previous controversial findings about the responses of these areas

Project development plan for the LANDSAT Imagery Verification and Extraction System (LIVES)

There are no author-identified significant results in this report

Implementation of the block-Krylov boundary flexibility method of component synthesis

A method of dynamic substructuring is presented which utilizes a set of static Ritz vectors as a replacement for normal eigenvectors in component mode synthesis. This set of Ritz vectors is generated in a recurrence relationship, which has the form of a block-Krylov subspace. The initial seed to the recurrence algorithm is based on the boundary flexibility vectors of the component. This algorithm is not load-dependent, is applicable to both fixed and free-interface boundary components, and results in a general component model appropriate for any type of dynamic analysis. This methodology was implemented in the MSC/NASTRAN normal modes solution sequence using DMAP. The accuracy is found to be comparable to that of component synthesis based upon normal modes. The block-Krylov recurrence algorithm is a series of static solutions and so requires significantly less computation than solving the normal eigenspace problem

Simulating hypervelocity impact effects on structures using the smoothed particle hydrodynamics code MAGI

Analysis of interaction occurring between space debris and orbiting structures is of great interest to the planning and survivability of space assets. Computer simulation of the impact events using hydrodynamic codes can provide some understanding of the processes but the problems involved with this fundamental approach are formidable. First, any realistic simulation is necessarily three-dimensional, e.g., the impact and breakup of a satellite. Second, the thickness of important components such as satellite skins or bumper shields are small with respect to the dimension of the structure as a whole, presenting severe zoning problems for codes. Thirdly, the debris cloud produced by the primary impact will yield many secondary impacts which will contribute to the damage and possible breakup of the structure. The problem was approached by choosing a relatively new computational technique that has virtues peculiar to space impacts. The method is called Smoothed Particle Hydrodynamics

Rotation and Macroturbulence in Metal-poor Field Red Giant and Red Horizontal Branch Stars

We report the results for rotational velocities, Vrot sin i, and macroturbulence dispersion, zeta(RT), for 12 metal-poor field red giant branch stars and 7 metal-poor field red horizontal branch stars. The results are based on Fourier transform analyses of absorption line profiles from high-resolution (R ~ 120,000), high-S/N (~ 215 per pixel) spectra obtained with the Gecko spectrograph at CFHT. We find that the zeta(RT) values for the metal-poor RGB stars are very similar to those for metal-rich disk giants studied earlier by Gray and his collaborators. Six of the RGB stars have small rotational values, less than 2.0 km/sec, while five show significant rotation, over 3 km/sec. The fraction of rapidly rotating RHB stars is somewhat lower than found among BHB stars. We devise two empirical methods to translate the line-broadening results obtained by Carney et al. (2003, 2008) into Vrot sin i for all the RGB and RHB stars they studied. Binning the RGB stars by luminosity, we find that most metal-poor field RGB stars show no detectable sign, on average, of rotation. However, the most luminous stars, with M(V) <= -1.5, do show net rotation, with mean values of 2 to 4 km/sec, depending on the algorithm employed, and these stars also show signs of radial velocity jitter and mass loss.Comment: accepted for publication in the Astronomical Journa

Una valoración de la geografía y la diáspora africana

El estudio de la diáspora Africana se ha vuelto un area vibrante de investigación y enseñanza en los años recientes a través de las disciplinas. Sin embargo, hay muy pocas contribuciones geográficas. Este artículo busca invertir esta tendencia. Se revisa el trabajo relevante de geógrafos en el Atlántico Negro para identificar temas prometedores para la investigación futura. La dispersión de plantas Africanas y el papel de los esclavos en establecer estas plantas es especialmente prometedor. Esta dirección de investigación clarifica los componentes Africanos de Intercambio Colombino mientras llama la atención sobre la importancia de la subsistencia en el negocio transatlántico de esclavos y la economía de las plantaciones. Las comidas básicas de origen Africano sirvieron a la subsistencia y a la memoria. Plantas Africanas figuran de manera prominente en los caminos de la comida en la diáspora, las practicas litúrgicas de las religiones Afro-sincréticas, y en las historias orales de Maroon

On the Elimination of the NATO Entitlement

For the last twenty years the U.S. has been living on borrowed time and money; we have gotten something for nothing. Now we must confront the painful opposite: nothing for something. A radical shift in our financial commitment to NATO will go a long way toward easing this pain and shoring up the competitive position of the U.S. going forward into the twenty-first century

Between Land and Sea: Mangroves and Mollusks along Brazil’s Mangal Coast

Westerners have long viewed mangroves as forbidding, pestilential landscapes. While modern medicine transformed their deadly reputation, the perception lingered of an environment that was little more than a tropical wasteland. The 1992 Earth Summit in Rio de Janeiro profoundly changed this view by drawing attention to the ecosystem as a habitat crucial to the life cycles of many species and endangered fauna yet increasingly at risk from deforestation. Conservation initiatives in the years since the Rio Summit, however, seldom recognize mangroves as a habitat that has also long supported human life. This is evident in the shell middens found along mangrove coasts and in the historical record of shellfish harvested for dietary protein. With a focus on Brazil, this article examines the shellfish that sustained Amerindians, enslaved Africans, and their descendants along the mangal coast since pre-Columbian times. The discussion contends that Brazil’s mangrove forests cannot be separated from the history of the tropical peoples who have successively lived in and managed this ecosystem from ancient times to the present. Finally, the article concludes that a research focus on shellfish suggests broader linkages to South Atlantic history.Os ocidentais há muito consideram os manguezais como paisagens proibitivas e pestilentas. Enquanto a medicina moderna transformou sua reputação mortal, a percepção permaneceu como de um ambiente que era pouco mais do que um deserto tropical. A Cúpula da Terra de 1992 no Rio de Janeiro mudou profundamente este ponto de vista, chamando a atenção para o ecossistema como um habitat crucial para os ciclos de vida de muitas espécies e fauna ameaçada, mas cada vez mais em risco de desmatamento. As iniciativas de conservação nos anos que se seguiram à Cúpula do Rio, entretanto, raramente reconhecem os manguezais como um habitat que há muito dá suporte à vida humana. Isto é evidente nos sambaquis encontrados ao longo dos Manguezais da costa e no registro histórico dos moluscos colhidos para a dieta proteica. Com foco no Brasil, este artigo examina os mariscos que sustentaram ameríndios, africanos escravizados, e seus descendentes ao longo dos Mangais da costa desde os tempos pré-Colombianos. A discussão alega que as florestas de manguezais do Brasil não podem ser separadas da história dos povos tropicais que viveram e manejaram esse ecossistema desde os tempos antigos até o presente. Finalmente, o artigo conclui que um foco de pesquisa sobre moluscos sugere laços mais amplos com a história do Atlântico Sul

On the Elimination of the NATO Entitlement

For the last twenty years the U.S. has been living on borrowed time and money; we have gotten something for nothing. Now we must confront the painful opposite: nothing for something. A radical shift in our financial commitment to NATO will go a long way toward easing this pain and shoring up the competitive position of the U.S. going forward into the twenty-first century