Flexibility of expressive timing in repeated musical performances

Performances by soloists in the Western classical tradition are normally highly prepared, yet must sound fresh and spontaneous. How do musicians manage this? We tested the hypothesis that they achieve the necessary spontaneity by varying the musical gestures that express their interpretation of a piece. We examined the tempo arches produced by final slowing at the ends of phrases in performances of J. S. Bach’s No. 6 (Prelude) for solo cello (12 performances) and the Italian Concerto (Presto) for solo piano (eight performances). The performances were given by two experienced concert soloists during a short time period (3½ months for the Prelude, 2 weeks for the Presto) after completing their preparations for public performance. We measured the tempo of each bar or half-bar, and the stability of tempo across performances (difference of the tempo of each bar/half bar from each of the other performances). There were phrase arches for both tempo and stability with slower, less stable tempi at beginnings and ends of phrases and faster, more stable tempi mid-phrase. The effects of practice were complex. Tempo decreased overall with practice, while stability increased in some bars and decreased in others. One effect of practice may be to imbue well-learned, automatic motor sequences with freshness and spontaneity through cognitive control at phrase boundaries where slower tempi and decreased stability provide opportunities for slower cognitive processes to modulate rapid automatic motor sequences

A longitudinal study of the development of expressive timing

Tempo arches have often been reported in polished music performances, but their development during the learning of a new piece has not been studied. We examined the development of expressive timing at three levels of musical structure (piece, section, phrase) as an experienced concert soloist (the second author) prepared the Prelude from J. S. Bach’s Suite No. 6 for solo cello for public performance. We used mixed effect models to assess the development of expressive timing and the effects of the performance cues (PCs) that the cellist used as mental landmarks to guide her performance. Tempo arches appeared early in practice at all three levels of musical structure and changed over time in complex ways, first becoming more pronounced and more asymmetrical and then shrinking somewhat in later performances. Arches were also more pronounced in phrases that contained PCs, suggesting that PCs reminded the cellist where to “breathe” between phrases. The early development of tempo arches suggests that they were an automatic product of basic cognitive or motor processes. The complex trajectory of their later development appeared to be the result, at least in part, of a deliberate communicative strategy intended to draw listeners’ attention to some musical boundaries more than others

Confinement of spinless particles by Coulomb potentials in two-dimensional space-time

The problem of confinement of spinless particles in 1+1 dimensions is approached with a linear potential by considering a mixing of Lorentz vector and scalar couplings. Analytical bound-states solutions are obtained when the scalar coupling is of sufficient intensity compared to the vector coupling.Comment: 14 pages, 2 figure

On The Distribution Of Siphonops Paulensis Boettger, 1892 (gymnophiona: Siphonopidae): Four New Brazilian State Records

Siphonops paulensis Boettger, 1892 is a Neotropical siphonopid caecilian widely distributed in South America. Herein, we fill knowledge gaps in the distribution of S. paulensis mostly in northeastern Brazil, including four new state records. © 2016 Check List and Authors.12

Panorama espaço - temporal de fatores de mudança economica, scoial e ambiental na Amazônia: estudo de caso Flona Tapajós.

Políticas públicas voltadas para integrar a Amazônia a outras regiões do Brasil na década de 1970 incluíram a instalação de portos, hidrelétricas e abertura de rodovias como a Transamazônica (BR 230) Cuiabá-Santarém (BR 163) e Belém - Brasília (BR 316), desencadeando um processo intenso de transformações na paisagem, principalmente pelo desflorestamento. Porém, neste mesmo período, também foram delimitadas áreas legalmente protegidas na região, como foi o caso da Floresta Nacional do Tapajós, criada em 1974. O objetivo do trabalho foi avaliar temporal e espacialmente forçantes promotoras de alterações na paisagem. Para tanto, foram utilizados dados secundários analíticos disponíveis em bases do IBGE, bem como informações espaciais disponibilizadas por órgãos públicos em âmbito federal, estadual e municipal. Variáveis topoclimáticas foram utilizadas nas avaliações da dinâmica espaço-temporal com auxílio de análises geoestísticas e modelagem. Os resultados reforçaram o modelo de ocupação denominado "espinha de peixe", tendo as rodovias como eixo de antropização e do aumento progressivo da pressão em Áreas Protegidas. Ao avaliar os cenários para 2030, observa-se os efeitos aos longo dos rios, a oeste do estado do Pará, pelas instalação de portos para escoamento da produção em mercado nacional e internacional

Fatores estruturais e desempenho industrial: as regiões sul, sudeste e nordeste do Brasil em camparação

In this article the author analyses in a comparative way, the industrial sector of the most important brazilian regions by estimating a gross profit function. This estimation permits to identify some regional structural particularities. On the other hand,it was possible to find some explicatory elements about the economic performance differential. His conclusions point out a tendency to a regional convergence of productivity and wages, and a better economic performance in the southern and northeastern regions. This tendency is associated to technological factors, to the scale of production and to agglomeration economies. However, the recent restruturation of the brazilian industry, aiming to become more competitive at an international level, indicate a possible spatial reconcentration which means a possible return to a divergent behavior of those economic indicators.Neste trabalho o autor analisa, comparativamente, a indústria das principais regiões brasileiras, por meio da estimativa de uma função excedente, permitindo-se identificar particularidades estruturais regionais, alem de serem fomecidoselementos explicativos sobre o diferencial de desempenho. Suas conclusões apontam parauma tendência a convergência regional da produtividade e dos salários, e um melhor desempenho do Sul e do Nordeste, tendência esta associada a tecnologia, a escala de produçao e as economias de aglomeração. No entanto, a recente reestruturagao da indústria brasileira, tendo em vista tomar-se mais competitiva em nível intemacional, vem dando sinais de uma possível reconcentração espacial, com retomo a divergência dos indicadores econõmicos em questao

Performance ao a thermal neutron radiographic system using imaging plates

A performance evaluation of a neutron radiographic system equipped with a thermal neutron sensitive imaging plate has been undertaken. It includes the assessment of spatial resolution, linearity, dynamic range and the response to exposure time, as well as a comparison of these parameters with the equivalent ones for neutron radiography employing conventional films and a gadolinium foil as converter. The evaluation and comparison between the radiographic systems have been performed at the Instituto de Engenharia Nuclear - CNEN, using the Argonauta Reactor as source of thermal neutrons and a commercially available imaging plate reade

Bounded solutions of neutral fermions with a screened Coulomb potential

The intrinsically relativistic problem of a fermion subject to a pseudoscalar screened Coulomb plus a uniform background potential in two-dimensional space-time is mapped into a Sturm-Liouville. This mapping gives rise to an effective Morse-like potential and exact bounded solutions are found. It is shown that the uniform background potential determinates the number of bound-state solutions. The behaviour of the eigenenergies as well as of the upper and lower components of the Dirac spinor corresponding to bounded solutions is discussed in detail and some unusual results are revealed. An apparent paradox concerning the uncertainty principle is solved by recurring to the concepts of effective mass and effective Compton wavelength.Comment: 15 pages, 7 figure

Specific heat and magnetic measurements in Nd0.5Sr0.5MnO3, Nd0.5Ca0.5MnO3 and Ho0.5Ca0.5MnO3 samples

We studied the magnetization as a function of temperature and magnetic field in the compounds Nd0.5Sr0.5MnO3, Nd0.5Ca0.5MnO3 and Ho0.5Ca0.5MnO3. It allowed us to identify the ferromagnetic, antiferromagnetic and charge ordering phases in each case. The intrinsic magnetic moments of Nd3+ and Ho3+ ions experienced a short range order at low temperatures. We also did specific heat measurements with applied magnetic fields between 0 and 9 T and temperatures between 2 and 300 K in all three samples. Close to the charge ordering and ferromagnetic transition temperatures the specific heat curves showed peaks superposed to the characteristic response of the lattice oscillations. Below 10 K the specific heat measurements evidenced a Schottky-like anomaly for all samples. However, we could not successfully fit the curves to either a two level nor a distribution of two-level Schottky anomaly. Our results indicated that the peak temperature of the Schottky anomaly was higher in the compounds with narrower conduction band.Comment: submitted to PR