Differential Algebras in Non-Commutative Geometry

We discuss the differential algebras used in Connes' approach to Yang-Mills theories with spontaneous symmetry breaking. These differential algebras generated by algebras of the form functions $\otimes$ matrix are shown to be skew tensorproducts of differential forms with a specific matrix algebra. For that we derive a general formula for differential algebras based on tensor products of algebras. The result is used to characterize differential algebras which appear in models with one symmetry breaking scale.Comment: 21 page

“So Succeeded by a Kind Providence”: Communities of Color in Eighteenth Century Boston

The Freedom Trail has become an iconic symbol and major tourist attraction in the City of Boston. Yet since its Cold War-era inception, the Freedom Trail has remained problematically focused on a consensus history of leading white men who brought forth the American Revolution. Other heritage trails - most notably the Black Heritage Trail - have been established to correct the deficiencies of the Freedom Trail. These organizations have attempted to provide a revisionist counter-point by telling stories of internal struggle and by exploring groups traditionally overlooked by historians. However, with so many trails possessing so many particularized foci, many different narratives compete for the limited attention of visitors to Boston. This divide among the different heritage trails threatens to resegregate history as perceived and interacted by the public. Using methods successfully employed in researching the antebellum black community on Beacon Hill, this thesis makes use of government minutes, deeds, court documents, census data, church records, and other public records to fill a gaping hole in the Freedom Trail`s narrative. Four generations of communities and people of color were studied, spanning the entire eighteenth century. Slavery dominated the lives of people of color through much of the century. However, by the 1760s, the first landowners of color on Beacon Hill purchased and developed their land: Tobias and Margaret Locker and Scipio and Venus Fayerweather. Others, such as Lancaster Hill, organized and petitioned against slavery and exploitation alongside the freemason Prince Hall. Following the Revolutionary War, the legacies of activism and property ownership combined on Beacon Hill. The Smith, Watts, and Barnes families are used as case studies of those who subdivided, developed, and sold land and homes along today`s Joy Street to house other families of color and formed a physical neighborhood that would thrive as black Beacon Hill for generations to come. Such stories bridge the interpretive gap between the Freedom Trail and the Black Heritage Trail, deepening the narrative of the former and building a prologue for the latter. The end result offers a far more vivid, critical, and complete public understanding of Boston`s history

How much control is enough? Optimizing fun with unreliable input

Brain-computer interfaces (BCI) provide a valuable new input modality within human- computer interaction systems, but like other body-based inputs, the system recognition of input commands is far from perfect. This raises important questions, such as: What level of control should such an interface be able to provide? What is the relationship between actual and perceived control? And in the case of applications for entertainment in which fun is an important part of user experience, should we even aim for perfect control, or is the optimum elsewhere? In this experiment the user plays a simple game in which a hamster has to be guided to the exit of a maze, in which the amount of control the user has over the hamster is varied. The variation of control through confusion matrices makes it possible to simulate the experience of using a BCI, while using the traditional keyboard for input. After each session the user �lled out a short questionnaire on fun and perceived control. Analysis of the data showed that the perceived control of the user could largely be explained by the amount of control in the respective session. As expected, user frustration decreases with increasing control. Moreover, the results indicate that the relation between fun and control is not linear. Although in the beginning fun does increase with improved control, the level of fun drops again just before perfect control is reached. This poses new insights for developers of games wanting to incorporate some form of BCI in their game: for creating a fun game, unreliable input can be used to create a challenge for the user

Repeated epitaxial growth and transfer of arrays of patterned, vertically aligned, crystalline Si wires from a single Si(111) substrate

Multiple arrays of Si wires were sequentially grown and transferred into a flexible polymer film from a single Si(111) wafer. After growth from a patterned, oxide-coated substrate, the wires were embedded in a polymer and then mechanically separated from the substrate, preserving the array structure in the film. The wire stubs that remained were selectively etched from the Si(111) surface to regenerate the patterned substrate. Then the growth catalyst was electrodeposited into the holes in the patterned oxide. Cycling through this set of steps allowed regrowth and polymer film transfer of several wire arrays from a single Si wafer

On the testability of coarsening assumptions: a hypothesis test for subgroup independence

Since coarse(ned) data naturally induce set-valued estimators, analysts often assume coarsening at random (CAR) to force them to be single-valued. Focusing on a coarse categorical response variable and a precisely observed categorical covariate, we re-illustrate the impossibility to test CAR and contrast it to another type of coarsening called subgroup independence (SI), using the data of the German Panel Study ``Labour Market and Social Security'' as an example. It turns out that -- depending on the number of subgroups and categories of the response variable -- SI can be point-identifying as CAR, but testable unlike CAR. A main goal of this paper is the construction of the likelihood-ratio test for SI. All issues are similarly investigated for the here proposed generalized versions, gCAR and gSI, thus allowing a more flexible application of this hypothesis test

Bacteria Hunt: A multimodal, multiparadigm BCI game

Brain-Computer Interfaces (BCIs) allow users to control applications by brain activity. Among their possible applications for non-disabled people, games are promising candidates. BCIs can enrich game play by the mental and affective state information they contain. During the eNTERFACE’09 workshop we developed the Bacteria Hunt game which can be played by keyboard and BCI, using SSVEP and relative alpha power. We conducted experiments in order to investigate what difference positive vs. negative neurofeedback would have on subjects’ relaxation states and how well the different BCI paradigms can be used together. We observed no significant difference in mean alpha band power, thus relaxation, and in user experience between the games applying positive and negative feedback. We also found that alpha power before SSVEP stimulation was significantly higher than alpha power during SSVEP stimulation indicating that there is some interference between the two BCI paradigms

Tumores adenomatoides uterinos: estudio anatomo-patológico e inmunohistoquímico de 32 casos

Indexación: ScieloAntecedentes: Los tumores adenomatoides (TA) son poco frecuentes. Se encuentran principalmente en el aparato reproductor femenino y especialmente en el útero. No existen reportes a nivel nacional sobre estos. Objetivos: Describir las características histológicas e inmunohistoquímicas de los TA uterinos. Método: Estudio descriptivo de 32 muestras ingresadas al Servicio de Anatomía Patológica de Clínica Las Condes. Las muestras estudiadas fueron recopiladas entre noviembre de 1999 y noviembre de 2008. Resultados: El diagnóstico de TA fue realizado en 21 histerectomías y 11 miomectomías. En 14 casos se diagnosticaron como lesiones nodulares únicas (43,8%) y en 18 junto a leiomiomas (56,2%). El tamaño promedio de las lesiones únicas fue 2,6 cm, significativamente mayor que aquellas asociadas a leiomiomas. El patrón histológico predominante más frecuente correspondió al tipo angiomatoide (81,3%), seguido por los patrones adenoide (9,4%), sólido (6,3%) y mixto (3%), no se encontraron TA quísticos. El estudio inmunohistoquími-co fue positivo en el 100% de los casos para citoqueratina AE1/AE3, calrretinina, vimentina y D2-40. Fue negativo para CD31 y CEA. Sólo un 6,3% (2 casos) fue positivo para citoqueratina 5/6. Conclusiones: Los TA corresponden a tumores benignos de origen mesotelial. Generalmente su diagnóstico es un hallazgo. Al presentarse en el útero, se confunden generalmente con leiomiomas o se presentan en conjunto con estos. En base a lo anterior el tratamiento de estas lesiones debe ser conservador, bastando con la resección del tumor.Background: The adenomatoid tumors (AT) are rare. They are found mainly in the female reproductive system and especially in the uterus. There is not national reporting on these. Objective: To describe the his-tological and immunohistochemical features of uterine AT. Method: Descriptive study of 32 patients admitíed to the Pathology Department of Clinica Las Condes. The cases studied were collected between November 1999 and November 2008. Results: The diagnosis of AT was performed in 21 hysterectomies and 11 myomectomies. In 14 patients were diagnosed as nodular single lesions (43.8%) and in 18 cases associated with leiomyomas (56.2%), the average size of single lesions was 2.6 cm, significantly greaterthan those associated with leiomyomas. The predominant histologic type most often correspond to angiomatoid (81.3%), followed by adenoid patterns (9.4%), solid (6.3%) and mixed (3%), the cystic pattern was not observed. The immunohistochemical study of ST was positive in 100% for cytokeratin AE1/AE3, calrretinin, vimentin and D2-40. It was negative for CD31 and CEA. Only 6.3% (2 cases) were positive for cytokeratin 5/6. Conclusio-ns: The AT is a benign tumor of mesothelial origin. Usually the diagnosis is a finding. In the uterus they are generally mistaken with leiomyomas or it is in associated with them. Based on the foregoing the treatment of AT should be conservative, only with resection.http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-75262009000600009&nrm=is