Attitude propagation using non-singular canonical variables

Three sets of non-singular canonical variables for the rotational motion are analyzed. These sets are useful when the angle between z-axis of a coordinate system fixed in artificial satellite ( here defined by the directions of principal moments of inertia of the satellite) and the rotational angular momentum vector is zero or when the angle between Z-inertial axis and rotational angular momentum vector is zero. The goal of this paper is to compare all these sets and to determine the benefits of their uses. With this objective, the dynamical equations of each set were derived, when mean hamiltonian associate with the gravity gradient torque is included. For the torque-free rotational motion, analytical solutions are computed for symmetrical satellite for each set of variables. When the gravity gradient torque is included, an analytical solution is shown for one of the sets and a numerical solution is obtained for one of the other sets. By this analysis we can conclude that: the dynamical equation for the first set is simple but it has neither clear geometrical nor physical meaning; the other sets have geometrical and physical meaning but their dynamical equations are more complex.

Spliceosomal Proteomics in Trypanosoma brucei Reveal New RNA Splicing Factors

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

Identification of SL addition trans-splicing acceptor sites in the internal transcribed spacer I region of pre-rRNA in Leishmania (Leishmania) amazonensis

Trypanosomatidae is a family of early branching eukaryotes harbouring a distinctive repertoire of gene expression strategies. Functional mature messenger RNA is generated via the trans-splicing and polyadenylation processing of constitutively transcribed polycistronic units. Recently, trans-splicing of pre-small subunit ribosomal RNA in the 5' external transcribed spacer region and of precursor tRNAsec have been described. Here, we used a previously validated semi-nested reverse transcription-polymerase chain reaction strategy to investigate internal transcribed spacer (ITS) I acceptor sites in total RNA from Leishmania (Leishmania) amazonensis. Two distinct spliced leader-containing RNAs were detected indicating that trans-splicing reactions occur at two AG acceptor sites mapped in this ITS region. These data provide further evidence of the wide spectrum of RNA molecules that act as trans-splicing acceptors in trypanosomatids.

Theoretical studies of mononuclear non-heme iron active sites

The quantum chemical investigations presented in this thesis use hybrid density functional theory to shed light on the catalytic mechanisms of mononuclear non-heme iron oxygenases, accommodating a ferrous ion in their active sites. More specifically, the dioxygen activation process and the subsequent oxidative reactions in the following enzymes were studied: tetrahydrobiopterin-dependent hydroxylases, naphthalene 1,2-dioxygenase and α-ketoglutarate-dependent enzymes. In light of many experimental efforts devoted to the functional mimics of non-heme iron oxygenases, the reactivity of functional analogues was also examined. The computed energetics and the available experimental data served to assess the feasibility of the reaction mechanisms investigated. Dioxygen activation in tetrahydrobiopterin- and α-ketoglutarate-dependent enzymes were found to involve a high-valent iron-oxo species, which was then capable of substrate hydroxylation. In the case of naphthalene 1,2-dioxygenase, the reactivity of an iron(III)-hydroxperoxo species toward the substrate was investigated and compared to the biomimetic counterpart.

Mass-accumulation rates for the non-authigenic, inorganic, crystalline, eolian component of sediments recovered at DSDP Sites 62-464 to 62-466

The mass-accumulation rate (MAR) of the non-authigenic, inorganic, crystalline component of deep-sea sediments from the Pacific aseismic rises apparently reflects influx of eolian sediment. The eolian sediment usually is dominated by volcanic material, except during glacial times. Sediments from Hess Rise provide a discontinuous record of eolian MARs. During Albian to Cenomanian time, the influx of volcanic material was fairly high (0.35-0.6 g/cm**2/10**3 yr), recording the latest stages of the Albian volcanism that formed Hess Rise. From the Campanian through the Paleocene, influx of eolian sediment was low, averaging 0.03 g/cm**2/10**3 yr. None of the four Hess Rise drill sites show evidence of the Late Cretaceous volcanic episode recorded at many sites now in the equatorial to subtropical Pacific. Pliocene to Pleistocene samples record a peak in volcanic influx about 4 to 5 m.y. ago, which has been well documented elsewhere. The several-fold increase in eolian accumulation rates elsewhere which are correlated with the onset of severe northernhemisphere glaciation 2.5 m.y. ago is not obvious in the Hess Rise data.

(Table 1) Percentage of non-opaque heavy minerals, heavy residue, magnetite, and opaque heavy minerals, DSDP Sites 58-445 and 58-446

Heavy-mineral analyses were made for 39 samples, 27 from DSDP Site 445 and 12 from Site 446. About one-fourth of the samples were so loose that they were easily disaggregated in water. The amount of heavy residue and the magnetite content of the heavy fraction were very high, 0.2 to 44 per cent and (on the average) more than 20 per cent, respectively. Among the non-opaque heavy minerals, common hornblende (0 to 80%) and augite (0 to 98%) are most abundant. Pale-green and bluish-green amphiboles (around 10%) and the epidote group (a few to 48%) are next in abundance. Euhedral apatite and biotite and irregularly shaped chromite are not abundant, but are present throughout the sequence. Hacksaw structure is developed in pale-green amphibole and augite. At Site 445, a fair amount of chlorite and a few glauconite(?) grains are present from Core 445-81 downward. The content of common hornblende and opaque minerals also changes from Core 445-81 downward. A geological boundary may exist between Cores 445-77 and 445-81. Source rocks of the sediments at both sites were basaltic volcanic rocks (possibly alkali suite), schists, and ultramafic rocks. The degree of lithification and amount of heavy residue, and the content of magnetite, non-opaque heavy minerals (excluding mafic minerals), and mafic minerals in the cores were compared with Eocene, Oligocene, and Miocene sandstones of southwest Japan. In many respects, the sediments at Sites 445 and 446 are quite different from those of southwest Japan. From the early Eocene to the early Miocene, the area of these sites belonged to a different geologic province than southwest Japan.

Splicing of constitutive upstream introns is essential for the recognition of intra-exonic suboptimal splice sites in the thrombopoietin gene

The human thrombopoietin (TPO) gene, which codes for the principal cytokine involved in platelet maturation, shows a peculiar alternative splicing of its last exon, where an intra-exonic 116 nt alternative intron is spliced out in a fraction of its mRNA. To characterize the molecular mechanism underlying this alternative splicing, minigenes of TPO genomic constructs with variable exon–intron configurations or carrying exclusively the TPO cDNA were generated and transiently transfected in the Hep3B cell line. We have found that the final rate of the alternative intron splicing is determined by three elements: the presence of upstream constitutive introns, the suboptimal splice sites of the alternative intron and the length of the alternative intron itself. Our results indicate that the recognition of suboptimal intra-exonic splice junctions in the TPO gene is influenced by the assembly of the spliceosome complex on constitutive introns and by a qualitative scanning of the sequence by the transcriptional/splicing machinery complex primed by upstream splicing signals.

The clergy-Man's vade mecum : part II : containing the canonical codes of the primitive, universal, Eastern, and Western Church, Down to the Year of our Lord, DCCLXXXVII, done from the original Greek and Latin, omitting no Canon, Decree, or any part of them that is curious or instructive ; with explanatory notes, a large index, and a preface shewing the usefulness of the work; with some reflections on moderate-non-conformity, and the rights of the church

Mode of access: Internet.

Functional-structural plant modelling using a combination of architectural analysis, L-systems and a canonical model of function

This paper presents a new method for producing a functional-structural plant model that simulates response to different growth conditions, yet does not require detailed knowledge of underlying physiology. The example used to present this method is the modelling of the mountain birch tree. This new functional-structural modelling approach is based on linking an L-system representation of the dynamic structure of the plant with a canonical mathematical model of plant function. Growth indicated by the canonical model is allocated to the structural model according to probabilistic growth rules, such as rules for the placement and length of new shoots, which were derived from an analysis of architectural data. The main advantage of the approach is that it is relatively simple compared to the prevalent process-based functional-structural plant models and does not require a detailed understanding of underlying physiological processes, yet it is able to capture important aspects of plant function and adaptability, unlike simple empirical models. This approach, combining canonical modelling, architectural analysis and L-systems, thus fills the important role of providing an intermediate level of abstraction between the two extremes of deeply mechanistic process-based modelling and purely empirical modelling. We also investigated the relative importance of various aspects of this integrated modelling approach by analysing the sensitivity of the standard birch model to a number of variations in its parameters, functions and algorithms. The results show that using light as the sole factor determining the structural location of new growth gives satisfactory results. Including the influence of additional regulating factors made little difference to global characteristics of the emergent architecture. Changing the form of the probability functions and using alternative methods for choosing the sites of new growth also had little effect. (c) 2004 Elsevier B.V. All rights reserved.

The Putative Leishmania Telomerase Rna (leishter) Undergoes Trans-splicing And Contains A Conserved Template Sequence.

Telomerase RNAs (TERs) are highly divergent between species, varying in size and sequence composition. Here, we identify a candidate for the telomerase RNA component of Leishmania genus, which includes species that cause leishmaniasis, a neglected tropical disease. Merging a thorough computational screening combined with RNA-seq evidence, we mapped a non-coding RNA gene localized in a syntenic locus on chromosome 25 of five Leishmania species that shares partial synteny with both Trypanosoma brucei TER locus and a putative TER candidate-containing locus of Crithidia fasciculata. Using target-driven molecular biology approaches, we detected a ∼2,100 nt transcript (LeishTER) that contains a 5' spliced leader (SL) cap, a putative 3' polyA tail and a predicted C/D box snoRNA domain. LeishTER is expressed at similar levels in the logarithmic and stationary growth phases of promastigote forms. A 5'SL capped LeishTER co-immunoprecipitated and co-localized with the telomerase protein component (TERT) in a cell cycle-dependent manner. Prediction of its secondary structure strongly suggests the existence of a bona fide single-stranded template sequence and a conserved C[U/C]GUCA motif-containing helix II, representing the template boundary element. This study paves the way for further investigations on the biogenesis of parasite TERT ribonucleoproteins (RNPs) and its role in parasite telomere biology.

Quantification and source identification of atmospheric particulate polycyclic aromatic hydrocarbons and their dry deposition fluxes at three sites in Salvador Basin, Brazil, impacted by mobile and stationary sources

The present work has aimed to determine the 16 US EPA priority PAH atmospheric particulate matter levels present in three sites around Salvador, Bahia: (i) Lapa bus station, strongly impacted by heavy-duty diesel vehicles; (ii) Aratu harbor, impacted by an intense movement of goods, and (iii) Bananeira village on Maré Island, a non vehicle-influenced site with activities such as handcraft work and fisheries. Results indicated that BbF (0.130-6.85 ng m-3) is the PAH with highest concentration in samples from Aratu harbor and Bananeira and CRY (0.075-6.85 ng m-3) presented higher concentrations at Lapa station. PAH sources from studied sites were mainly of anthropogenic origin such as gasoline-fueled light-duty vehicles and diesel-fueled heavy-duty vehicles, discharges in the port, diesel burning from ships, dust ressuspension, indoor soot from cooking, and coal and wood combustion for energy production.

Association of Trypanosoma vivax in extracellular sites with central nervous system lesions and changes in cerebrospinal fluid in experimentally infected goats

Changes in cerebrospinal fluid (CSF) and anatomical and histopathological central nervous system (CNS) lesions were evaluated, and the presence of Trypanosoma vivax in CNS tissues was investigated through PCR. Twelve adult male goats were divided into three groups (G): G1, infected with T. vivax and evaluated during the acute phase; G2, infected goats evaluated during the chronic phase; and G3, consisting of non-infected goats. Each goat from G1 and G2 was infected with 1.25 x 10(5) trypomastigotes. Cerebrospinal fluid (CSF) analysis and investigation of T. vivax was performed at the 15(th) day post-infection (dpi) in G1 goats and on the fifth day after the manifestation of nervous system infection signs in G2 goats. All goats were necropsied, and CNS fragments from G1 and G2 goats were evaluated by PCR for the determination of T. vivax. Hyperthermia, anemia and parasitemia were observed from the fifth dpi for G1 and G2, with the highest parasitemia peak between the seventh and 21(st) dpi. Nervous system infection signs were observed in three G2 goats between the 30(th) and 35(th) dpi. CSF analysis revealed the presence of T. vivax for G2. Meningitis and meningoencephalitis were diagnosed in G2. PCR were positive for T. vivax in all the samples tested. In conclusion, T. vivax may reach the nervous tissue resulting in immune response from the host, which is the cause of progressive clinical and pathological manifestations of the CNS in experimentally infected goats.