Embryogenesis and metamorphosis in a haplosclerid demosponge: gastrulation and transdifferentiation of larval ciliated cells to choanocytes

Early development and metamorphosis of Reniera sp., a haplosclerid demosponge, have been examined to determine how gastrulation occurs in this species, and whether there is an inversion of the primary germ layers at metamorphosis. Embryogenesis occurs by unequal cleavage of blastomeres to form a solid blastula consisting micro- and macromeres; multipolar migration of the micromeres to the surface of the embryo results in a bi-layered embryo and is interpreted as gastrulation. Polarity of the embryo is determined by the movement of pigment-containing micromeres to one pole of the embryo; this pole later becomes the posterior pole of the swimming larva. The bi-layered larva has a fully differentiated monociliated outer cell layer, and a solid interior of various cell types surrounded by dense collagen. The pigmented cells at the posterior pole give rise to long cilia that are capable of responding to environmental stimuli. Larvae settle on their anterior pole. Fluorescent labeling of the monociliated outer cell layer with a cell-lineage marker (CMFDA) demonstrates that the monociliated cells resorb their cilia, migrate inwards, and transdifferentiate into the choanocytes of the juvenile sponge, and into other amoeboid cells. The development of the flagellated choanocytes and other cells in the juvenile from the monociliated outer layer of this sponge's larva is interpreted as the dedifferentiation of fully differentiated larval cells-a process seen during the metamorphosis of other ciliated invertebrate larvae-not as inversion of the primary germ layers. These results suggest that the sequences of development in this haplosclerid demosponge are not very different than those observed in many cnidarians.

Quantum interference in optical fields and atomic radiation

We discuss the connection between quantum interference effects in optical beams and radiation fields emitted from atomic systems. We illustrate this connection by a study of the first- and second-order correlation functions of optical fields and atomic dipole moments. We explore the role of correlations between the emitting systems and present examples of practical methods to implement two systems with non-orthogonal dipole moments. We also derive general conditions for quantum interference in a two-atom system and for a control of spontaneous emission. The relation between population trapping and dark states is also discussed. Moreover, we present quantum dressed-atom models of cancellation of spontaneous emission, amplification on dark transitions, fluorescence quenching and coherent population trapping.

The damped and coherently-driven Jaynes-Cummings model

We investigate the influence of a single-mode cavity on the Autler-Townes doublet that arises when a three-level atom is strongly driven by a laser field tuned to one of the atomic transitions and probed by a tunable, weak field coupled to the other transition. We assume that the cavity mode is coupled to the driven transition and the cavity and laser frequencies are equal to the atomic transition frequency. We find that the Autler-Townes spectrum can have one, two or three peaks depending on the relative magnitudes of the Rabi frequencies of the cavity and driving fields. We show that, in order to understand the three-peaked spectrum, it is necessary to go beyond the secular approximation, leading to interesting quantum interference effects. We find that the positions and relative intensities of the three spectral components are affected strongly by the atom-cavity coupling strength g and the cavity damping K. For an increasing g and/or decreasing K the triplet evolves into a single peak. This results in 'undressing' of the system such that the atom collapses into its ground state. We interpret the spectral features in terms of the semiclassical dressed-atom model, and also provide complementary views of the cavity effects in terms of quantum Langevin equations and the fully quantized, 'double -dressing' model.

Linear ketenimines. Variable structures of C,C-dicyanoketenimines and C,C-bis-sulfonylketenimines

C,C-Dicyanoketenimines 10a-c were generated by flash vacuum thermolysis of ketene NS-acetals 9a-c or by thermal or photochemical decomposition of alpha-azido-,beta-cyanocinnamonitrile 11. In the latter reaction, 3,3-dicyano-2-phenyl-1-azirine 12 is also formed. IR spectroscopy of the keteniminines isolated in Ar matrixes or as neat films, NMR spectroscopy of 10c, and theoretical calculations (B3LYP/6-31G*) demonstrate that these ketenimines have variable geometry, being essentially linear along the CCN-R framework in polar media (neat films and solution), but in the gas phase or Ar matrix they are bent, as is usual for ketenimines. Experiments and calculations agree that a single CN substituent as in 13 is not enough to enforce linearity, and sulfonyl groups are less effective that cyano groups in causing linearity. C,C-Bis(methylsulfonyl)ketenimines 4-5 and a C-cyano-C-(methylsulfonyl)ketenimine 15 are not linear. The compound p-O2NC6H4N=C= C(COOMe)2 previously reported in the literature is probably somewhat linearized along the CCNR moiety. A computational survey (B3LYP/6-31G*) of the inversion barrier at nitrogen indicates that electronegative C-substituents dramatically lower the barrier; this is also true of N-acyl substituents. Increasing polarity causes lower barriers. Although N-alkylbis(methylsulfonyl)ketenimines are not calculated to be linear, the barriers are so low that crystal lattice forces can induce planarity in N-methylbis(methylsulfonyl)ketenimine 3.

Chebyshev real wave packet propagation: H+O-2 (J=0) state-to-state reactive scattering calculations

In this paper we explore the relative performance of two recently developed wave packet methodologies for reactive scattering, namely the real wave packet Chebyshev domain propagation of Gray and Balint-Kurti [J. Chem. Phys. 108, 950 (1998)] and the Lanczos subspace wave packet approach of Smith [J. Chem. Phys. 116, 2354 (2002); Chem. Phys. Lett. 336, 149 (2001)]. In the former method, a modified Schrodinger equation is employed to propagate the real part of the wave packet via the well-known Chebyshev iteration. While the time-dependent wave packet from the modified Schrodinger equation is different from that obtained using the standard Schrodinger equation, time-to-energy Fourier transformation yields wave functions which differ only trivially by normalization. In the Lanczos subspace approach the linear system of equations defining the action of the Green operator may be solved via either time-dependent or time-independent methods, both of which are extremely efficient due to the simple tridiagonal structure of the Hamiltonian in the Lanczos representation. The two different wave packet methods are applied to three dimensional reactive scattering of H+O-2 (total J=0). State-to-state reaction probabilities, product state distributions, as well as initial-state-resolved cumulative reaction probabilities are examined. (C) 2002 American Institute of Physics.

Segregation in binary and ternary liquid fluidized beds

The mechanism underlying segregation in liquid fluidized beds is investigated in this paper, A binary fluidized bed system not at a stable equilibrium condition. is modelled in the literature as forming a mixed part-corresponding to stable mixture-at the bottom of the bed and a pure layer of excess components always floating on the mixed part. On the basis of this model: (0 comprehensive criteria for binary particles of any type to mix/segregate, and (ii) mixing, segregation regime map in terms of size ratio and density ratio of the particles for a given fluidizing medium, are established in this work. Therefore, knowing the properties of given particles, a second type of particles can be chosen in order to avoid or to promote segregation according to the particular process requirements. The model is then advanced for multicomponent fluidized beds and validated against experimental results observed for ternary fluidized beds. (C) 2002 Elsevier Science B.V. All rights reserved.

Quantum theory of the far-off-resonance continuous-wave Raman laser: Heisenberg-Langevin approach

We present the quantum theory of the far-off-resonance continuous-wave Raman laser using the Heisenberg-Langevin approach. We show that the simplified quantum Langevin equations for this system are mathematically identical to those of the nondegenerate optical parametric oscillator in the time domain with the following associations: pump pump, Stokes signal, and Raman coherence idler. We derive analytical results for both the steady-state behavior and the time-dependent noise spectra, using standard linearization procedures. In the semiclassical limit, these results match with previous purely semiclassical treatments, which yield excellent agreement with experimental observations. The analytical time-dependent results predict perfect photon statistics conversion from the pump to the Stokes and nonclassical behavior under certain operational conditions.

Boletim eletr??nico de bibliografias especializadas: pol??tica energ??tica - setor el??trico

A implementa????o de uma Pol??tica Energ??tica ?? essencial para o desenvolvimento do Pa??s, na medida em que estabelece metas, meios e diretrizes para melhorar a confiabilidade e a qualidade do suprimento energ??tico. Ela define ainda o papel dos diversos agentes e institui????es que atuam na ??rea energ??tica brasileira. A exist??ncia de tal pol??tica ?? condi????o fundamental para garantir o planejamento das atividades energ??ticas, tanto do lado da produ????o quanto do consumo, sem comprometer o meio ambiente e a qualidade de vida das pr??ximas gera????es. Em fun????o da import??ncia da pol??tica energ??tica ao desenvolvimento sustent??vel e ?? melhoria do bemestar da popula????o brasileira, a 1?? edi????o de 2013 do Boletim Eletr??nico de Bibliografias Especializadas destaca o tema Pol??tica Energ??tica - Setor El??trico, com indica????es de publica????es pertencentes ao acervo da Biblioteca Graciliano Ramos/ENAP. O intuito ?? divulgar obras que possam auxiliar gestores, servidores e trabalhadores da ??rea de Energia no Brasil em seus processos decis??rios, assim como obras que tratam da rica hist??ria do setor e seus planos para o futuro.

Boletim eletr??nico de bibliografias especializadas: gest??o de crise

O terceiro Boletim de Bibliografias Especializadas apresenta o tema ???Gest??o de Crise???, com indica????es de livros e artigos de revistas sobre o tema pertencentes ao acervo da Biblioteca. Essas publica????es mostram que a gest??o de crise ?? uma problem??tica com a qual toda administra????o deve preocupar-se. Afinal, crise ?? um evento imprevis??vel capaz de provocar preju??zos significativos a uma institui????o e, consequentemente, aos seus integrantes. Uma quest??o que se apresenta ??: depois da crise instaurada, como gerenci??-la? O conhecimento das caracter??sticas de uma crise possibilitar?? compreend??-la melhor e facilitar?? o ??rduo esfor??o em gerenci??-la.

Boletim eletr??nico de bibliografias especializadas:acesso ?? informa????o p??blica

A Lei de Acesso ?? Informa????o (n??12.527/2011) entra em vigor hoje, dia 16 de maio, e traz importantes mudan??as para a administra????o p??blica. A nova legisla????o proporciona, ao cidad??o brasileiro, o acesso amplo ??s informa????es e a documentos p??blicos sob a guarda do Estado. A partir dessa data, todo cidad??o poder??, a qualquer momento, solicitar informa????es diversas, sem necessidade de motiva????o para seu uso, garantindo, assim, o exerc??cio de seu direito constitucional ao acesso ?? informa????o p??blica. A Lei estabelece que o acesso seja a regra e o sigilo, a exce????o. Diante desse cen??rio, o 5?? Boletim Eletr??nico de Bibliografias Especializadas destaca o tema ???Acesso ?? informa????o???, com indica????es de publica????es pertencentes ao acervo da Biblioteca Graciliano Ramos/ENAP. O intuito ?? divulgar obras que auxiliem servidores p??blicos na compreens??o dos princ??pios da nova Lei e na mudan??a da cultura do sigilo, ainda presente na gest??o da informa????o p??blica.

Boletim eletr??nico de bibliografias especializadas: pol??ticas p??blicas em direitos humanos

Os direitos humanos s??o os direitos essenciais a todos os seres humanos, sem que haja discrimina????o por ra??a, cor, g??nero, idioma, nacionalidade ou por qualquer outro motivo. Eles podem ser civis ou pol??ticos, como o direito ?? vida, ?? igualdade perante a lei e ?? liberdade de express??o. Podem tamb??m ser econ??micos, sociais e culturais, como o direito ao trabalho e ?? educa????o e coletivos, como o direito ao desenvolvimento. As Pol??ticas P??blicas em Direitos Humanos ?? tema deste boletim bibliogr??fico, o qual traz publica????es que mostram que estas n??o devem ser apenas programas governamentais, mas um instrumento de participa????o da sociedade civil na delimita????o do espa??o p??blico.

Boletim eletr??nico de bibliografias especializadas: gest??o de pessoas no servi??o p??blico

Diante de uma sociedade mais din??mica e complexa, a ado????o de uma pol??tica permanente de desenvolvimento do capital humano ?? o caminho para a supera????o dos desafios no setor p??blico. Dessa forma ?? poss??vel ofertar servi??os de excel??ncia aos cidad??os, bem como promover a inova????o e a melhoria na qualidade da gest??o p??blica. O presente Boletim apresenta uma sele????o de publica????es, dentre a vasta quantidade de obras sobre o tema existentes no acervo da Biblioteca Graciliano Ramos, que retratam os obst??culos existentes para o desenvolvimento de pessoas no servi??o p??blico, com o objetivo de convergir as necessidades e anseios dos quadros funcionais ??s necessidades organizacionais

Boletim eletr??nico de bibliografias especializadas: qualifica????o e valoriza????o dos servidores p??blicos

O dia do servidor p??blico ?? comemorado em 28 de outubro desde 1937, quando da cria????o do Conselho Federal do Servi??o P??blico Civil. Desde ent??o, muito se conquistou em rela????o ao reconhecimento desse profissional. Hoje, os servidores t??m consci??ncia da import??ncia de sua atua????o para o desenvolvimento econ??mico e social do pa??s. O incentivo aos servidores p??blicos, por meio de a????es voltadas ?? forma????o e ?? capacita????o permanentes, ?? fundamental para motiv??-los a prestar servi??os de excel??ncia aos cidad??os. Com base na pol??tica vigente e em homenagem ao dia do servidor, a Biblioteca Graciliano Ramos traz como tema de seu 9?? Boletim Eletr??nico de Bibliografias Especializadas uma sele????o de publica????es, pertencentes ao seu acervo, que abordam a quest??o da qualifica????o e da valoriza????o dos servidores p??blicos

Boletim eletr??nico de bibliografias especializadas: igualdade racial

Indicadores socioecon??micos apontam que as expressivas diferen??as raciais existentes no Brasil t??m reflexos na educa????o, sa??de, renda, viol??ncia, expectativa de vida etc. Diante desse conjunto cada vez mais evidente de desigualdades, o debate p??blico sobre essa tem??tica tem se intensificado, assim como as iniciativas no campo das pol??ticas p??blicas. A Organiza????o Internacional do Trabalho (OIT) afirma que, para combater o comportamento social provocado pelo racismo, ?? necess??rio demonstrar sua exist??ncia e os mecanismos pelos quais ele opera. Tendo em vista tal conjuntura, o presente Boletim divulga as publica????es do acervo da Biblioteca Graciliano Ramos, da ENAP, que trazem contribui????es ao tema da Igualdade Racial

Boletim eletr??nico de bibliografias especializadas: meio ambiente e sustentabilidade

A 3a edi????o de 2013 do Boletim Eletr??nico de Bibliografias Especializadas re??ne publica????es do acervo da Biblioteca Graciliano Ramos com a tem??tica Meio Ambiente e Sustentabilidade, por ocasi??o do Dia Mundial do Meio Ambiente, comemorado anualmente em 5 de junho. A data busca chamar a aten????o e a a????o pol??tica de povos e pa??ses a fim de aumentar a conscientiza????o e a preserva????o ambiental. A divulga????o das publica????es a seguir - que tratam de ecologia, saneamento b??sico, polui????o, desenvolvimento sustent??vel, economia verde, gest??o ambiental, entre outros - tem como expectativa apoiar a forma????o e a capacita????o de servidores p??blicos, bem como a aplica????o desse conhecimento em pol??ticas p??blicas, em benef??cio da popula????o