Digit systems over commutative rings

Let epsilon be a commutative ring with identity and P is an element of epsilon[x] be a polynomial. In the present paper we consider digit representations in the residue class ring epsilon[x]/(P). In particular, we are interested in the question whether each A is an element of epsilon[x]/(P) can be represented modulo P in the form e(0)+ e(1)x + ... + e(h)x(h), where the e(i) is an element of epsilon[x]/(P) are taken from a fixed finite set of digits. This general concept generalizes both canonical number systems and digit systems over finite fields. Due to the fact that we do not assume that 0 is an element of the digit set and that P need not be monic, several new phenomena occur in this context.

Percepção dos efeitos do trabalho em turnos sobre a saúde e a vida social em funcionários da enfermagem em um hospital universitário do Estado de São Paulo

O trabalho em turnos existe desde o início da vida social dos homens, sendo utilizado em diferentes setores, como na indústria de produção de bens de consumo e de serviços. A área da saúde exige o sistema em turnos para manutenção de atividades durante 24 horas. Teve-se como objetivo identificar os sistemas de turnos em funcionários de enfermagem em um hospital universitário, avaliar a percepção sobre os prováveis efeitos do trabalho em turnos em sua saúde e vida social e o grau de participação desses funcionários na forma de organização de sua jornada. Trata-se de uma pesquisa descritiva e exploratória, cujos resultados foram obtidos mediante questionário aplicado a 348 funcionários da enfermagem do Hospital de Clínicas da Faculdade de Medicina de Botucatu, São Paulo. Dentre os resultados, observou-se que, em sua maioria, eles tinham menos de 40 anos, eram casados, do sexo feminino, com um filho pelo menos, cumprindo uma escala de turnos alternados, com freqüência de revezamento superior a quinze dias e referindo queixas de caráter neuro-psíquico, gastrintestinal e cardiovascular. Houve ainda queixas sobre relacionamento e tempo de convivência. Na maioria das vezes, era pouca a participação do funcionário na forma de organização de sua escala de trabalho.

LARGE ATOMIC and NUCLEAR THREE-BODY SYSTEMS: SCATTERING and BINDING

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Electronic ballast for multiple fluorescent lamp systems

An electronic ballast for multiple tubular fluorescent lamp systems is presented. The proposed structure has a high value for the power factor, a dimming capability, and soft switching of the semiconductor devices operated at high frequencies. A zero-current switching pulse width modulated SEPIC converter is used as the rectifying stage and it is controlled using the instantaneous average input current technique. The inverting stage consists of classical resonant half-bridge converter with series-resonant parallel-loaded filters. The dimming control technique is based on varying the switching frequency and monitoring the phase shift of the current drained by the filters and lamps in order to establish a closed loop control. Experimental results are presented that validate the theoretical analysis.

Sistemas dinâmicos finitos: Paciência Búlgara (Shift em partições e composições cíclicas)

Pós-graduação em Matemática - IBILCE

Effect of temperature on salt-salt aqueous biphasic systems: manifestations of upper critical solution temperature

Water-miscible ionic liquids (ILs) may be salted out using kosmotropic salts such as potassium phosphate (K3PO4) to form salt-salt aqueous biphasic systems (ABS). The effect of temperature on these systems has been studied using phase diagrams and it is observed that the degree of binodal shift decreases (requiring lower IL and kosmotropic salt concentrations) with the increase of temperature following the trend [C(4)mim]Cl > [C(4)py]Cl > [C(4)mmim] Cl > [N-4444]Cl. This trend can be correlated with the decreasing hydrogen bonding abilities of each salt. The phase behavior was also interpreted on the basis of critical solution temperature behavior of pure aqueous ionic liquid solutions. Additionally, the distribution of alcohols in these systems was studied as a function of temperature and it was found that the distribution ratios did not change with changes in temperature. The Gibbs energy of transfer of a methylene group in these systems and correlation to tie-line length was also determined. It was concluded that while the miscibility of alcohols increases in the ILs with increasing temperature, phase divergence in the aqueous biphasic system decreases, and thus these competing forces tend to cancel each other out for small polar molecules. A comparison is provided for the response to temperature in the currently studied salt-salt systems and analogous ABS formed by the addition of hydrophilic polymers to kosmotropic salts (polymer-salt) or other polymers (polymer-polymer).

Catastrophic regime shift in water reservoirs and São Paulo water supply crisis

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)