1,361 research outputs found

    Influence of drainage status on soil and water chemistry, litter decomposition and soil respiration in central Amazonian forests on sandy soils

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    Central Amazonian rainforest landscape supports a mosaic of tall terra firme rainforest and ecotone campinarana, riparian and campina forests, reflecting topography-induced variations in soil, nutrient and drainage conditions. Spatial and temporal variations in litter decomposition, soil and groundwater chemistry and soil CO2 respiration were studied in forests on sandy soils, whereas drought sensitivity of poorly-drained valley soils was investigated in an artificial drainage experiment. Slightly changes in litter decomposition or water chemistry were observed as a consequence of artificial drainage. Riparian plots did experience higher litter decomposition rates than campina forest. In response to a permanent lowering of the groundwater level from 0.1 m to 0.3 m depth in the drainage plot, topsoil carbon and nitrogen contents decreased substantially. Soil CO2 respiration decreased from 3.7±0.6 ”mol m-2 s-1 before drainage to 2.5±0.2 and 0.8±0.1 ”mol m-2 s-1 eight and 11 months after drainage, respectively. Soil respiration in the control plot remained constant at 3.7±0.6 ”mol m-2 s-1. The above suggests that more frequent droughts may affect topsoil carbon and nitrogen content and soil respiration rates in the riparian ecosystem, and may induce a transition to less diverse campinarana or short-statured campina forest that covers areas with strongly-leached sandy soil

    Reports of Cases Adjudged in the Supreme Court of the Province of New Brunswick

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    Reports of Cases Adjudged in the Supreme Court of the Province of New Brunswick: Commencing in Hilary Term, 1835, written by George F. S. Berton in 1835 is a 217 page compilation of cases argued and determined in the Supreme Court of New Brunswick. It includes an index and the option to full-text search. Preface: At the date of the commencement of these Reports, I was in­duced by a desire to render service to my professional brethren and the public, to publish the notes, which I had taken only for my own use, of the cases in Hilary, 1835. They first appeared in the Royal Gazette, and were then issued in pamphlet form. I continued so to publish the cases determined during that year. In the Session of 1836, the Legislature, satisfied of the “ great importance of obtaining correct reports of the decisions of the Su­preme Court,” authorized the Lieutenant Governor to appoint a Reporter, secured to him the copyright of his work, and granted an annual sum as a remuneration for his services. Under this Act I had the honor to be appointed, and have, from the time of my appointment, carefully collected and reported all the decisions of the Court. Among the cases of 1835, there were several of very great and general importance, and as I was enabled, by the kindness of their Honors the Chief Justice and the other Judges, to have access to their notes and written judgments; I considered it only due to the liberality and kindness with which my efforts had been met, to re-publish the whole of the cases from the beginning of 1835 ; this has now been done, and although I have thereby incurred a heavy pecuniary expense, yet I shall be enabled to proceed with more satisfaction to myself and the public than I could by Continuing a work im­perfectly commenced. Much delay has occurred in the printing, but I am now induced to hope that the work will be proceeded with diligently until completed, and that hereafter the numbers will be issued within a reasonable time after every Term. It is proper that I should acknowledge the very great assistance which, during along illness, I have received from Mr. George Lee, as well in compiling the latter part of the cases now published, as in the general correction of the Press. G. F. S. Berton. Fredericton, January, 1839.https://digitalcommons.schulichlaw.dal.ca/thompsonrarebooks/1000/thumbnail.jp

    Long term survival of mature autotransplanted teeth: A retrospective single center analysis

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    Objective: The replacement of an irremediably compromised tooth requires an implant rehabilitation or a traditional fixed partial denture. In well-selected cases, a further therapeutic possibility is represented by tooth autotransplantation. Although dental transplants are poorly understood and practiced, the international literature agrees that it is considered the first choice when applicable. The advantages of this technique are numerous: use of an autologous element, maintenance of tissue trophism, aesthetic and functional restoration, costs reduction. Although autotransplantation is often performed with immature teeth, even mature teeth with fully formed apex can be used as donors. The aim of the present work was to analyze consecutive cases of completely formed donor teeth autotransplantations performed from 2005 to 2011 in 21 patients for evaluating the survival and success rate. Materials and methods: The medical records of patients who underwent transplantation in a specialized center in Rimini (Italy) from 2005 to 2011 were checked. Only transplants of mature donor molars were considered. Patients were called up to evaluate the survival rate and success rate. Results: The mean age at the time of the surgery was 33,6 \ub1 7,4; mean follow up was 11,9 years \ub11,9. Success rate at the time of latest recall visit was 80 % and survival 95 % of the analyzed cases. Conclusions: The survival and success rate are in complete agreement with the most recent literature and confirm that the technique of autotransplantation is reliable when indications and protocols are rigidly followed, also using mature teeth as donors

    A spectroscopic analysis of a sample of narrow-line Seyfert 1 galaxies selected from the Sloan Digital Sky Survey

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    We revisited the spectroscopic characteristics of narrow-line Seyfert 1 galaxies (NLS1s) by analysing a homogeneous sample of 296 NLS1s at redshift between 0.028 and 0.345, extracted from the Sloan Digital Sky Survey (SDSS-DR7) public archive. We confirm that NLS1s are mostly characterized by Balmer lines with Lorentzian profiles, lower black hole masses and higher Eddington ratios than classic broad-line Seyfert 1 (BLS1s), but they also appear to be active galactic nuclei (AGNs) contiguous with BLS1s and sharing with them common properties. Strong Fe II emission does not seem to be a distinctive property of NLS1s, as low values of Fe II/HÎČ\beta are equally observed in these AGNs. Our data indicate that Fe II and Ca II kinematics are consistent with the one of HÎČ\beta. On the contrary, O I λ\lambda8446 seems to be systematically narrower and it is likely emitted by gas of the broad-line region more distant from the ionizing source and showing different physical properties. Finally, almost all NLS1s of our sample show radial motions of the narrow-line region highly-ionised gas. The mechanism responsible for this effect is not yet clear, but there are hints that very fast outflows require high continuum luminosities (> 104410^{44} erg/s) or high Eddington ratios (log(Lbol_{\rm bol}/LEdd_{\rm Edd}) > -0.1).Comment: 27 pages, 31 figures, 4 tables, accepted for publication in MNRA

    [O III] line properties in two samples of radio-emitting narrow-line Seyfert 1 galaxies

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    The [O III] λλ\lambda\lambda 4959,5007 lines are a useful proxy to test the kinematic of the narrow-line region (NLR) in active galactic nuclei (AGN). In AGN, and particularly in narrow-line Seyfert 1 galaxies (NLS1s) these lines often show few peculiar features, such as blue wings, often interpreted as outflowing component, and a shift −- typically toward lower wavelengths −- of the whole spectroscopic feature in some exceptional sources, the so-called blue outliers, which are often associated to strong winds. We investigated the incidence of these peculiarities in two samples of radio-emitting NLS1s, one radio-loud and one radio-quiet. We also studied a few correlations between the observational properties of the [O III] lines and those of the AGN. Our aim was to understand the difference between radio-quiet and radio-loud NLS1s, which may in turn provide useful information on the jet formation mechanism. We find that the NLR gas is much more perturbed in radio-loud than in radio-quiet NLS1s. In particular the NLR dynamics in Îł\gamma-ray emitting NLS1s appears to be highly disturbed, and this might be a consequence of interaction with the relativistic jet. The less frequently perturbed NLR in radio-quiet NLS1s suggests instead that these sources likely do not harbor a fully developed relativistic jet. Nonetheless blue-outliers in radio-quiet NLS1s are observed, and we interpret them as a product of strong winds.Comment: 16 pages, 13 figures, 7 tables, accepted for publication on Astronomy & Astrophysic

    HIV-1 Tat alters neuronal intrinsic excitability

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    Objective: In HIV+ individuals, the virus enters the central nervous system and invades innate immune cells, producing important changes that result in neurological deficits. We aimed to determine whether HIV plays a direct role in neuronal excitability. Of the HIV peptides, Tat is secreted and acts in other cells. In order to examine whether the HIV Tat can modify neuronal excitability, we exposed primary murine hippocampal neurons to that peptide, and tested its effects on the intrinsic membrane properties, 4 and 24 h after exposure. Results: The exposure of hippocampal pyramidal neurons to Tat for 4 h did not alter intrinsic membrane properties. However, we found a strong increase in intrinsic excitability, characterized by increase of the slope (Gain) of the input-output function, in cells treated with Tat for 24 h. Nevertheless, Tat treatment for 24 h did not alter the resting membrane potential, input resistance, rheobase and action potential threshold. Thus, neuronal adaptability to Tat exposure for 24 h is not applicable to basic neuronal properties. A restricted but significant effect on coupling the inputs to the outputs may have implications to our knowledge of Tat biophysical firing capability, and its involvement in neuronal hyperexcitability in neuroHIV

    High resolution spectroscopy of the extended narrow-line region of IC 5063 and NGC 7212

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    We studied the properties of the gas of the extended narrow line region (ENLR) of two Seyfert 2 galaxies: IC 5063 and NGC 7212. We analysed high resolution spectra to investigate how the main properties of this region depend on the gas velocity. We divided the emission lines in velocity bins and we calculated several line ratios. Diagnostic diagrams and SUMA composite models (photo-ionization + shocks), show that in both galaxies there might be evidence of shocks significantly contributing in the gas ionization at high |V|, even though photo-ionization from the active nucleus remains the main ionization mechanism. In IC 5063 the ionization parameter depends on V and its trend might be explained assuming an hollow bi-conical shape for the ENLR, with one of the edges aligned with the galaxy disk. On the other hand, NGC 7212 does not show any kind of dependence. The models show that solar O/H relative abundances reproduce the observed spectra in all the analysed regions. They also revealed an high fragmentation of the gas clouds, suggesting that the complex kinematics observed in these two objects might be caused by interaction between the ISM and high velocity components, such as jets.Comment: 29 pages, 32 figures, accepted for publication in MNRA

    Banks, Firms, and Jobs

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    We analyze the heterogeneous employment effects of financial shocks using a rich data set of job contracts, matched with the universe of firms and their lending banks in one Italian region. To isolate the effect of the financial shock, we construct a firm-specific time-varying measure of credit supply. The preferred estimate indicates that the average elasticity of employment to a credit supply shock is 0.36⁠. Adjustment affects both the extensive and the intensive margins and is concentrated among workers with temporary contracts. We also examine the heterogeneous effects of the credit crunch by education, age, gender and nationality

    Impact of Obesity on the Drug-Drug Interaction Between Dolutegravir and Rifampicin or Any Other Strong Inducers

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    BACKGROUND: Obesity is increasingly prevalent among people with HIV. Obesity can impact drug pharmacokinetics and consequently the magnitude of drug-drug interactions (DDIs) and, thus, the related recommendations for dose adjustment. Virtual clinical DDI studies were conducted using physiologically based pharmacokinetic (PBPK) modeling to compare the magnitude of the DDI between dolutegravir and rifampicin in nonobese, obese, and morbidly obese individuals. METHODS: Each DDI scenario included a cohort of virtual individuals (50% female) between 20 and 50 years of age. Drug models for dolutegravir and rifampicin were verified against clinical observed data. The verified models were used to simulate the concurrent administration of rifampicin (600 mg) at steady state with dolutegravir (50 mg) administered twice daily in normal-weight (BMI 18.5-30 kg/m(2)), obese (BMI 30-40 kg/m(2)), and morbidly obese (BMI 40-50 kg/m(2)) individuals. RESULTS: Rifampicin was predicted to decrease dolutegravir area under the curve (AUC) by 72% in obese and 77% in morbidly obese vs 68% in nonobese individuals; however, dolutegravir trough concentrations were reduced to a similar extent (83% and 85% vs 85%). Twice-daily dolutegravir with rifampicin resulted in trough concentrations always above the protein-adjusted 90% inhibitory concentration for all BMI groups and above the 300 ng/mL threshold in a similar proportion for all BMI groups. CONCLUSIONS: The combined effect of obesity and induction by rifampicin was predicted to further decrease dolutegravir exposure but not the minimal concentration at the end of the dosing interval. Thus, dolutegravir 50 mg twice daily with rifampicin can be used in individuals with a high BMI up to 50 kg/m(2)
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