929 resultados para Catiline, approximately 108 B.C.-62 B.C.
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In this paper we investigate the temperature variation of the mass of waste along the depth in a household waste landfill of Rio Claro - SP, São Paulo, having a climate characterized as Tropical Altitude. In this research, there were two holes in two distinct points of the landfill, with different depths and characteristics in order to fix several thermal sensors - RTDs - to record the temperature at predetermined depths. Overall, the results show the influence of temperature at depths of up to 3.0 meters (from the surface) and that it varies in a manner to stabilize at depths above 5.0 meters. The highest temperature obtained was approximately 37.5 ° C for a time of waste disposal of 7 to 10 years. The results showed the presence of organic matter (substrate) which resulted in elevated temperature resulting from biological activity
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
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This work comprises three different types of unconventional correlated systems.rnChapters 3-5 of this work are about the open shell compounds Rb4O6 and Cs4O6. These mixed valent compounds contain oxygen in two different modifications: the closed-shell peroxide anion is nonmagnetic, whereas the hyperoxide anion contains an unpaired electrons in an antibonding pi*-orbital. Due to this electron magnetic ordering is rendered possible. In contrast to theoretical predictions, which suggested half-metallic ferromagnetism for Rb4O6,rndominating antiferromagnetic interactions were found in the experiment. Besidesrna symmetry reduction due to the mixed valency, strong electronic correlations of this highly molecular system determine its properties; it is a magnetically frustrated insulator. The corresponding Cs4O6 was found to show similar properties.rnChapters 6-9 of this work are about intermetallic Heusler superconductors. rnAll of these superconductors were rationally designed using the van Hove scenario as a working recipe. A saddle point in the energy dispersion curve of a solid leads to a van Hove singularity in the density of states. In the Ni-based and Pd-based Heusler superconductors presented in this work this sort of a valence instability occurs at the high-symmetry L point and coincides or nearly coincides with the Fermi level. The compounds escape the high density of states at the Fermi energy through a transition into the correlated superconducting state.rnChapter 10 of this work is about the tetragonally distorted ferrimagnetic DO22 phase of Mn3Ga. This hard-magnetic modification is technologically useful for spin torque transfer applications. The phase exhibits two different crystallographic sites that are occupied by Mn atoms and can thus be written as Mn2MnGa. The competition between the mainly itinerant moments of the Mn atoms at the Wyckoff position 4d and the localized moments of the Mn atoms at the Wyckoff position 2b leads to magnetic correlations. The antiferromagnetic orientation of these moments determines the compound to exhibit a resulting magnetic moment of approximately 1 µB per formula unit in a partially compensated ferrimagnetic configuration.
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The fluorinated olefinic peptide nucleic acid (F-OPA) system was designed as a peptide nucleic acid (PNA) analogue in which the base carrying amide moiety was replaced by an isostructural and isoelectrostatic fluorinated C-C double bond, locking the nucleobases in one of the two possible rotameric forms. By comparison of the base-pairing properties of this analogue with its nonfluorinated analogue OPA and PNA, we aimed at a closer understanding of the role of this amide function in complementary DNA recognition. Here we present the synthesis of the F-OPA monomer building blocks containing the nucleobases A, T, and G according to the MMTr/Acyl protecting group scheme. Key steps are a selective desymmetrization of the double bond in the monomer precursor via lactonization as well as a highly regioselective Mitsunobu reaction for the introduction of the bases. PNA decamers containing single F-OPA mutations and fully modified F-OPA decamers and pentadecamers containing the bases A and T were synthesized by solid-phase peptide chemistry, and their hybridization properties with complementary parallel and antiparallel DNA were assessed by UV melting curves and CD spectroscopic methods. The stability of the duplexes formed by the decamers containing single (Z)-F-OPA modifications with parallel and antiparallel DNA was found to be strongly dependent on their position in the sequence with T(m) values ranging from +2.4 to -8.1 degrees C/modification as compared to PNA. Fully modified F-OPA decamers and pentadecamers were found to form parallel duplexes with complementary DNA with reduced stability compared to PNA or OPA. An asymmetric F-OPA pentadecamer was found to form a stable self-complex (T(m) approximately 65 degrees C) of unknown structure. The generally reduced affinity to DNA may therefore be due to an increased propensity for self-aggregation
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Tricyclo (tc)-DNA belongs to the class of conformationally constrained DNA analogs that show enhanced binding properties to DNA and RNA. We prepared tc-oligonucleotides up to 17 nt in length, and evaluated their binding efficiency and selectivity towards complementary RNA, their biological stability in serum, their RNase H inducing potential and their antisense activity in a cellular assay. Relative to RNA or 2'-O-Me-phosphorothioate (PS)-RNA, fully modified tc-oligodeoxynucleotides, 10-17 nt in length, show enhanced selectivity and enhanced thermal stability by approximately 1 degrees C/modification in binding to RNA targets. Tricyclodeoxyoligonucleotides are completely stable in heat-deactivated fetal calf serum at 37 degree C. Moreover, tc-DNA-RNA duplexes are not substrates for RNase H. To test for antisense effects in vivo, we used HeLa cell lines stably expressing the human beta-globin gene with two different point mutations in the second intron. These mutations lead to the inclusion of an aberrant exon in beta-globin mRNA. Lipofectamine-mediated delivery of a 17mer tc-oligodeoxynucleotide complementary to the 3'-cryptic splice site results in correction of aberrant splicing already at nanomolar concentrations with up to 100-fold enhanced efficiency relative to a 2'-O-Me-PS-RNA oligonucleotide of the same length and sequence. In contrast to 2'-O-Me-PS-RNA, tc-DNA shows antisense activity even in the absence of lipofectamine, albeit only at much higher oligonucleotide concentrations.
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The Tibetan highlands host the largest alpine grassland ecosystems worldwide, bearing soils that store substantial stocks of carbon (C) that are very sensitive to land use changes. This study focuses on the cycling of photoassimilated C within a Kobresia pygmaea pasture, the dominating ecosystems on the Tibetan highlands. We investigated short-term effects of grazing cessation and the role of the characteristic Kobresia root turf on C fluxes and belowground C turnover. By combining eddy-covariance measurements with 13CO2 pulse labeling we applied a powerful new approach to measure absolute fluxes of assimilates within and between various pools of the plant-soil-atmosphere system. The roots and soil each store roughly 50% of the overall C in the system (76 Mg C/ha), with only a minor contribution from shoots, which is also expressed in the root:shoot ratio of 90. During June and July the pasture acted as a weak C sink with a strong uptake of approximately 2 g C/m**2/ in the first half of July. The root turf was the main compartment for the turnover of photoassimilates, with a subset of highly dynamic roots (mean residence time 20 days), and plays a key role for the C cycling and C storage in this ecosystem. The short-term grazing cessation only affected aboveground biomass but not ecosystem scale C exchange or assimilate allocation into roots and soil.
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Apolipoprotein A-1 (apoA-1) in complex with high-density lipoprotein is critically involved in the transport and metabolism of cholesterol and in the pathogenesis of atherosclerosis. We reexamined the thermal unfolding of lipid-free apoA-1 in low-salt solution at pH approximately 7, by using differential scanning calorimetry and circular dichroism. At protein concentrations <5 mg/ml, thermal unfolding of apoA-1 is resolved as an extended peak (25 degrees C-90 degrees C) that can be largely accounted for by a single reversible non-two-state transition with midpoint Tm 57 +/- 1 degree C, calorimetric enthalpy deltaH(Tm)= 200 +/- 20 kcal/mol (1 kcal = 4.18 kJ), van't Hoff enthalpy deltaHv(Tm) approximately 32.5 kcal/mol, and cooperativity deltaHv(Tm)/deltaH(Tm) approximately 0.16. The enthalpy deltaH(Tm) can be accounted for by melting of the alpha-helical structure that is inferred by CD to constitute approximately 60% of apoA-1 amino acids. Farand near-UV CD spectra reveal noncoincident melting of the secondary and tertiary structural elements and indicate a well-defined secondary structure but a largely melted tertiary structure for apoA-1 at approximately 37 degrees C and pH 7. This suggests a molten globular-like state for lipid-free apoA-1 under near-physiological conditions. Our results suggest that in vivo lipid binding by apoA-1 may be mediated via the molten globular apolipoprotein state in plasma.
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Replacement of the phosphodiester linkages of the polyanion DNA with guanidine linkers provides the polycation deoxynucleic guanidine (DNG). The synthesis of pentameric thymidyl DNA is provided. This polycationic DNG species binds with unprecedented affinity and with base-pair specificity to negatively charged poly(dA) to provide both double and triple helices. The dramatic stability of these hybrid structures is shown by their denaturation temperatures (Tm). For example, the double helix of the pentameric thymidyl DNG and poly(dA) does not dissociate in boiling water (ionic strength = 0.12), whereas the Tm for pentameric thymidyl DNA associated with poly(dA) is approximately 13 degrees C (ionic strength = 0.12). The effect of ionic strength on Tm for DNG complexes with DNA shows an opposite correlation compared with double-stranded DNA and is much more dramatic than for double-stranded DNA.
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A new planktic foraminifer transfer function (GSF18) related 5 North Atlantic assemblages to winter and summer sea surface temperature. GSF18, based on recombined and simplified core top census data, preserves most environmental information and reproduces modern North Atlantic conditions with approximately the same accuracy as previous transfer functions, but can be more readily applied to faunal samples ranging in age from Pliocene to Holocene. Transfer function GSF18 has been applied to faunal data from Deep Sea Drilling Project Hole 552A to produce a 2.5 m.y. sea-surface temperature (SST) time series. Estimates show several periods between 2.3 and 4.6 Ma during which mean SST's were both several degrees warmer and several degrees cooler than modern conditions. Between 2.9 and 4.0 Ma SST was generally warmer than modern except for a 250 k.y. interval centered at 3.3 Ma. Maximum SST, with respect to modern conditions, occurred after the cool interval near 3.1 Ma when SST was approximately 3.6° C warmer than present conditions. Comparison of SST estimates with stable isotope data suggest that after peak warming at 3.1 Ma, there was an overall surface water cooling with concomitant build up of global ice volume, culminating in Northern Hemisphere glaciation. This event is also indicated by the presence of ice rafted detritus in 552A sediments at about 2.45 Ma.
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Editor's name, d. C. Lambot, at head of title.
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Objective-To determine the effects of various vehicles on the penetration and retention of hydrocortisone applied to canine skin. Sample Population-20 canine skin samples obtained from the thorax, neck, and groin regions of 5 Greyhounds. Procedure-Skin was harvested from dogs after euthanasia and stored at -20 degrees C until required. The skin was then defrosted and placed into diffusion cells, which were maintained at approximately 32 degrees C by a water bath. Saturated solutions of hydrocortisone that contained trace amounts of radiolabelled [C-14]-hydrocortisone in each vehicle (ie, PBS solution [PBSS] alone, 50% ethanol [EtOH] in PBSS [wt/wt], and 50% propylene glycol in PBSS [wt/wt]) were applied to the outer (stratum corneum) surface of each skin sample, and aliquots of receptor fluid were collected for 24 hours and analyzed for hydrocortisone. Results-The maximum flux of hydrocortisone was significantly higher for all sites when dissolved in a vehicle containing 50% EtOH, compared with PBSS alone or 50% propylene glycol, with differences more prominent in skin from the neck region. In contrast, higher residues of hydrocortisone were found remaining within the skin when PBSS alone was used as a vehicle, particularly in skin from the thorax and neck. Conclusions and Clinical Relevance-Penetration of topically applied hydrocortisone is enhanced when EtOH is used in vehicle formulation. Significant regional differences (ie, among the thorax, neck, and groin areas) are also found in the transdermal penetration and skin retention of hydrocortisone. Variability in clinical response to hydrocortisone can be expected in relation to formulation design and site of application.
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The effects of three vehicles, phosphate-buffered saline (PBS), ethanol (50% in PBS w/w) and propylene glycol (50% in PBS w/w) on in vitro transdermal penetration of testosterone was investigated in the horse. Skin was harvested from the thorax of five Thoroughbred horses after euthanasia and stored at -20 degrees C until required. The skin was then defrosted and placed into Franz-type diffusion cells, which were maintained at approximately 32 degrees C by a water bath. Saturated solutions of testosterone, containing trace amounts of radiolabelled [C-14]testosterone, in each vehicle were applied to the outer (stratum corneum) surface of each skin sample and aliquots of receptor fluid were collected at 0, 2, 4, 8, 16, 20, 22 and 24 h and analysed for testosterone by scintillation counting. The maximum flux (J(max)) of testosterone was significantly higher for all sites when testosterone was dissolved in a vehicle containing 50% ethanol or 50% propylene glycol, compared to PBS. In contrast, higher residues of testosterone were found remaining within the skin when PBS was used as a vehicle. This study shows that variability in clinical response to testosterone could be expected with formulation design.
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Fibre Bragg gratings at 1568nm have been inscribed in single mode TOPAS microstructured polymer optical fibre to characterise thermal and humidity sensitivity of the fibres in the 1550nm spectral region. Results demonstrate a temperature sensitivity of approximately -36 pm/°C and a humidity sensitivity of no more than - 0.59 pm/%RH. The fibre material appears to be very attractive for long term monitoring of high strains because of its insensitivity to humidity.
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Eddy covariance (EC) estimates of carbon dioxide (CO2) fluxes and energy balance are examined to investigate the functional responses of a mature mangrove forest to a disturbance generated by Hurricane Wilma on October 24, 2005 in the Florida Everglades. At the EC site, high winds from the hurricane caused nearly 100% defoliation in the upper canopy and widespread tree mortality. Soil temperatures down to -50 cm increased, and air temperature lapse rates within the forest canopy switched from statically stable to statically unstable conditions following the disturbance. Unstable conditions allowed more efficient transport of water vapor and CO2 from the surface up to the upper canopy layer. Significant increases in latent heat fluxes (LE) and nighttime net ecosystem exchange (NEE) were also observed and sensible heat fluxes (H) as a proportion of net radiation decreased significantly in response to the disturbance. Many of these impacts persisted through much of the study period through 2009. However, local albedo and MODIS (Moderate Resolution Imaging Spectro-radiometer) data (the Enhanced Vegetation Index) indicated a substantial proportion of active leaf area recovered before the EC measurements began 1 year after the storm. Observed changes in the vertical distribution and the degree of clumping in newly emerged leaves may have affected the energy balance. Direct comparisons of daytime NEE values from before the storm and after our measurements resumed did not show substantial or consistent differences that could be attributed to the disturbance. Regression analyses on seasonal time scales were required to differentiate the storm's impact on monthly average daytime NEE from the changes caused by interannual variability in other environmental drivers. The effects of the storm were apparent on annual time scales, and CO2 uptake remained approximately 250 g C m-2 yr-1 lower in 2009 compared to the average annual values measured in 2004-2005. Dry season CO2 uptake was relatively more affected by the disturbance than wet season values. Complex leaf regeneration dynamics on damaged trees during ecosystem recovery are hypothesized to lead to the variable dry versus wet season impacts on daytime NEE. In contrast, nighttime CO2 release (i.e., nighttime respiration) was consistently and significantly greater, possibly as a result of the enhanced decomposition of litter and coarse woody debris generated by the storm, and this effect was most apparent in the wet seasons compared to the dry seasons. The largest pre- and post-storm differences in NEE coincided roughly with the delayed peak in cumulative mortality of stems in 2007-2008. Across the hurricane-impacted region, cumulative tree mortality rates were also closely correlated with declines in peat surface elevation. Mangrove forest-atmosphere interactions are interpreted with respect to the damage and recovery of stand dynamics and soil accretion processes following the hurricane.