The effects of selected modern technological concepts on the performance and handling characteristics of LTA vehicles

The results of an airship design sensitivity study are presented. A wide variety of airship design concepts, including the classical and high aero-lift augmented-hybrids are examined with regard to specific technological improvements, and consequent gains in performance, stability and control and flying qualities. Variations in size, payload, power required and airspeed are quantitatively analyzed for airships representing aero-to-buoyant lift ratios of zero to 3.0 over a range of technology improvements implying reduced drag, reduced structural weight fractions and lighter, more efficient propulsion systems. Qualitatively, future airships are discussed in terms of stability, control and flying qualities requirements dictated by projected demands for vastly improved operational effectiveness and ease of handling. Such topics include stability augmentation systems, load-alleviation systems and total computer state-sensing and controls management systems. It was shown that, for the most part, highly refined conventional designs offer attractive gains in both performance and ease of handling. Hybrid airships represent a good potential for missions requiring the transport of heavy payloads at higher airspeeds over shorter ranges without the capability for sustained hover and vertical flight

Localização de espécies florestais nativas em fragmentos da Floresta Ombrófila Mista no território centro-sul do Paraná.

EVINCI. Resumo

Elaboração de um mapa índice e um sistema de informação geográfica das espécies de interesse.

EVINCI. Resumo

Molecular Pharmacology of Somatostatin Receptors

Somatostatin (somatotropin release inhibitory factor, SRIF), inhibits animal cell secretion and proliferation. SRIF is transcribed from a single gene as a 1 t 6 amino acid that in precursor is cleaved a cell specific manner into two distinct peptides, SRIF-14 and SRIF-28. Each binds with high affinity to all five known SRIF-receptor subtypes (sst, - ssts) and several of these receptor subtypes are endogenously expressed in the AtT-20 cell, a murine pituitary corticotroph. SRIF receptors belong to the G protein-coupled family of integral membrane receptors. Within the SRIF receptor family, it has been shown that the sst, receptor subtype exists as splice-variants (sstzA and sst28) that exhibit over-lapping tissue expression. The sstzA and sstze splice-variants occur within the carboxyl-tenninus of the receptor, an area of the protein, which is not involved in ligand binding, thereby making a phannacologic distinction of these two subtypes extremely difficult. Indeed, the function of these receptor splice-variants, as well as the significance of their cellular co-expression is unknown. To delineate the function of these closely related receptors, we have employed double-stranded RNA interference ( dsRNAi), a highly selective post-transcriptional gene silencing method. dsRNAi allows sst2A mRNA to be specifically targeted and inhibited while testing the functional capabilities of the remaining receptor population. When used in conjunction with receptor subtype selective agonists, dsRNAi provides a powerful genetic tool to explore receptor function. In the current study, we inhibit the expression of the sshA receptor with dsRNAi, and examine the functional consequences of this inhibition by monitoring receptor protein expression with subtype selective antibodies, as well as assessing the functional consequences of this inhibition on intracellular cAMP accumulation. Our results demonstrate that RNA silencing oligonucleotides against the sshA carboxyl terminus can be incorporated into AtT-20 cells in a time and concentration-dependent manner. Furthermore, the uptake of these sst2A inactivating oligonuclcotides, suppresses sst?A receptor expression and inhibits receptor cyclic nucleotide effects. Taken together, these results suggest that RNA interference is a promising approach to defining the function of highly homologous receptors that cannot be distinguished through conventional phannacologic approaches

Kinks and waterfalls as signatures of competing order in angle-resolved photoemission spectra of La_{2-x}Sr_xCuO_4

We show that the so-called kinks and waterfalls observed in angle-resolved photoemission spectra of La2-xSrxCuO4, a prototypical high-Tc superconducting cuprate, result from the coupling of quasiparticles with two distinct nearly critical collective modes with finite characteristic wave vectors, typical of charge and spin fluctuations near a stripe instability. Both phonon-like charge and spin collective modes are needed to account for the kinked quasiparticle dispersions. This clarifies the long-standing question whether kinks are due to phonons or spin waves and the nature of the bosonic mediators of the electron-electron effective interaction in La2-xSrxCuO4.Comment: 5 pages, 4 figure

Estudo da fenologia reprodutiva da guabiroba (Campomanesia Xanthocarpa Berg.) na floresta nacional de Irati.

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Fenologia reprodutiva de Maytenus ilicifolia (Celastraceae) na Floresta Nacional de Irati, Paraná, Brasil.

(Reproductive phenology of Maytenus ilicifolia (Celastraceae) in the Irati National Forest, Paraná, Brazil). The present study investigates the reproductive phenology of a natural population of Maytenus ilicifolia Mart. ex Reissek from the Mixed Ombrophylous Forest (Araucaria Forest). The phenological study was carried out from April 2003 to March 2005, on 78 adult trees. The intensity of phenological events was estimated based on the scale of Fournier. The population showed seasonal behavior. A significant correlation was observed between temperature, day length and flowering. Two floral types were identified, one pistillate and the other staminate, and together with the phenology patterns results a dioecious characteristic for the species is suggested