1,823 research outputs found

    Chemostratigraphy of the Pliensbachian, Puesto Araya Formation (Neuquén Basin, Argentina)

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    In a preliminary attempt to establish an isotope stratigraphy, strontium, carbon and oxygen isotope ratios were determined from marine biogenic carbonates of Pliensbachian age, in the context of scheme of local ammonite Zones correlatable to the European Standard Zonation. Two sections, rio Atuel and arroyo Serrucho, of the mainly siliciclastic Puesto Araya Formation, Neuquen Basin, south-western Mendoza, Argentina, were studied. Specimens of the bivalve genera Weyla Bhom and Gryphaea Lamarck were selected for the isotopic determinations because of their low-Mg calcite original mineralogy and widespread presence. Scanning electron microscopy, X-ray diffraction and X-ray fluorescence spectrometry techniques were used to control the good degree of preservation of most of the biogenic material, as evidenced by pristine fabrics, 100% calcite composition and Sr, Mn and Fe concentrations. Although strontium isotope ratios are slightly scattered, it is possible to compare them with those of the Early Jurassic seawater reference curve. Carbon isotope signals show two relative maxima, correlatable with those recorded for the upper part of the Ibex Zone and the middle part of the Margaritatus Zone in various European sections, indicating the possible global significance of these events. d18O values were found to be unreliable for isotope stratigraphy, as they are largely depleted in comparison to those of coeval unaltered marine carbonates

    Efeito da aplicação de diferentes regimes de rega deficitária no pessegueiro ‘Sweet Dream’ cultivado num pomar da região da Beira Interior.

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    Efeito da aplicação de diferentes regimes de rega deficitária no pessegueiro ‘Sweet Dream’ cultivado num pomar da região da Beira Interior.info:eu-repo/semantics/publishedVersio

    Efeito da aplicação de diferentes regimes de rega deficitária no pessegueiro ‘Sweet Dream’ cultivado num pomar da região da Beira Interior.

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    Efeito da aplicação de diferentes regimes de rega deficitária no pessegueiro ‘Sweet Dream’ cultivado num pomar da região da Beira Interior.info:eu-repo/semantics/publishedVersio

    Renal Allograft Rupture: A Clinicopathologic Review

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    Transplantation Proceedings Volume 32, Issue 8, December 2000, Pages 2597-2598 -------------------------------------------------------------------------------- doi:10.1016/S0041-1345(00)01801-7 | How to Cite or Link Using DOI Copyright © 2000 Elsevier Science Inc. All rights reserved. Cited By in Scopus (4) Permissions & Reprints Renal allograft rupture: a clinicopathologic review M Ramosa, , L Martinsa, L Diasa, A.C Henriquesa, J Soaresa, J Queirósa and A.M Sarmentoa aDepartments of Urology and Nefrology, Hospital Geral de Santo António, Oporto, Portugal Available online 19 December 2000. Article Outline Patients and methods Results Discussion References Renal allograft rupture (RAR) is a rare but very serious complication of renal transplantation, requiring emergency surgery. The most common cause is acute allograft rejection, but other causes such as renal vein thrombosis (RVT), acute tubular necrosis (ATN), renal biopsy, and lymphatic obstruction have been reported.[1] and [2] We reviewed our experience with the aim of identifying RAR predisposing conditions. Patients and methods In a consecutive series of 934 renal transplants performed between July 1983 and September 1999, 11 patients (1.2%) had RAR. In these cases we studied donor and recipient characteristics, preservation conditions, clinical signs and symptoms, treatment, and pathology findings. This group of patients was then compared with their paired cohort. Data analysis was computer-based. In the statistical analysis t test and Fisher’s exact test were used. Results All 11 kidneys that suffered RAR were from cadaver donors, nine male and two female. The mean age was 29.5 years with good terminal serum creatinine (mean 1.1 mg/dL). All organs were stored in Eurocollins solution and the mean cold ischemia time was 21 hours and 25 minutes (range, 10 hours to 29 hours and 20 minutes). Excluding one black patient, all recipients were Caucasian. Eight were female and 3 were male, with a mean age of 33.8 years. The mean HLA match was 1.7, and the mean peak panel reactive antibody (PRA) was 22% (range 0 to 93%) and current was 15% (range 0 to 67%). All patients had cyclosporine treatment, eight had delayed graft function requiring dialysis, and three underwent renal allograft biopsy. In two patients rupture occurred in the second allograft; the others were first transplants. The day of RAR was a mean of 5.3 (range 2 to 13). All patients had new onset of severe allograft pain, eight had a drop in daily hematocrit, and six had hypotension. The four patients with more precocious ruptures had sudden onset of bleeding through the drainage tube. Transplant nephrectomy was performed in 10 patients, and surgical conservative treatment with fibrin glue and collagen foam was performed in one. All patients survived RAR. Three had a second transplant and currently have functioning allografts. Pathology examination revealed RVT in three patients and some degree of rejection in the remaining eight. One patient had a rupture on the second day because of hyperacute rejection, and three had severe acute cellular rejection, but in four patients the dominant figure was ATN with minimal rejection. Excluding the patient with hyperacute rejection, the day of rupture was later for those with severe acute rejection, a mean of 9.6 days (range 6 to 13). In those with ATN, the day of RAR was a mean of 4.5 (range 3 to 6) and the patients with RVT had ruptures even sooner, on mean third day (range 2 to 4). Variables associated with RAR were: sex mismatch (P = .004), current PRA (P = .012), and a need for dialysis (P = .042). Age of the recipient, transplant number, cold ischemia time, total HLA match, and peak PRA were not associated with RAR. Discussion Higher current PRA and a need for dialysis are variables associated with rejection and ATN. Therefore they are expected to be related to rupture. The well-documented conditions that are associated with ATN and rejection3 must be the same, which in extreme conditions predispose to RAR. We find no explanation for the statistically significant association of sex mismatch and RAR, other than random error. Acute allograft rejection is the most frequent cause of graft rupture in the literature (60 to 80%),3 but ATN has received little note. In our series, ATN was responsible for 36% of the ruptures, as much as severe acute rejection. ATN alone can cause RAR,4 because of interstitial edema and rise in intrarenal pressure. But when associated with rejection, it seems that these two conditions can act synergistically to cause allograft rupture. Our data suggests that rupture occurs later when caused by rejection, rather than when RVT is responsible. To our knowledge this finding had never been reported in world literature. Perhaps the timing of RVT is related to technical problems, such as twisting and kinking of the vein or intima tear, although the thrombogenic effect of cyclosporine can also have a role in this process.5 All these patients were on cyclosporine therapy, which may explain the small number of RAR caused by rejection alone and the significant number of patients that had RVT (27%). It appears that cyclosporine therapy is changing the etiology of the graft rupture.6 References 1 T. Grochowiecki, J. Szmidt and K. Madej et al., Transplantation Proc 28 (1996), p. 3461. View Record in Scopus | Cited By in Scopus (2) 2 R.S. Lord, D.J. Effeney and J.M. Hayes et al., Ann Surg 177 (1973), p. 268. Full Text via CrossRef | View Record in Scopus | Cited By in Scopus (4) 3 G.J. Azar, A. Zarifian and G.D. Frentz et al., Clin Transplantation 10 (1996), p. 635. View Record in Scopus | Cited By in Scopus (12) 4 Y.H. Chan, K.M. Wong and K.C. Lee et al., Am J Kidney Dis 34 (1999), p. 355. Abstract | Article | PDF (86 K) 5 R.M. Jones, J.A. Murie and A. Ting et al., Clin Transplant 2 (1988), p. 122. 6 A.J. Richardson, R.M. Higgins and A.J. Jaskowski et al., Br J Surg 77 (1990), p. 558. Full Text via CrossRef | View Record in Scopus | Cited By in Scopus (19

    Neutron structure function and inclusive DIS from H-3 and He-3 at large Bjorken-x

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    A detailed study of inclusive deep inelastic scattering (DIS) from mirror A = 3 nuclei at large values of the Bjorken variable x is presented. The main purpose is to estimate the theoretical uncertainties on the extraction of the neutron DIS structure function from such nuclear measurements. On one hand, within models in which no modification of the bound nucleon structure functions is taken into account, we have investigated the possible uncertainties arising from: i) charge symmetry breaking terms in the nucleon-nucleon interaction, ii) finite Q**2 effects neglected in the Bjorken limit, iii) the role of different prescriptions for the nucleon Spectral Function normalization providing baryon number conservation, and iv) the differences between the virtual nucleon and light cone formalisms. Although these effects have been not yet considered in existing analyses, our conclusion is that all these effects cancel at the level of ~ 1% for x < 0.75 in overall agreement with previous findings. On the other hand we have considered several models in which the modification of the bound nucleon structure functions is accounted for to describe the EMC effect in DIS scattering from nuclei. It turns out that within these models the cancellation of nuclear effects is expected to occur only at a level of ~ 3%, leading to an accuracy of ~ 12 % in the extraction of the neutron to proton structure function ratio at x ~ 0.7 -0.8$. Another consequence of considering a broad range of models of the EMC effect is that the previously suggested iteration procedure does not improve the accuracy of the extraction of the neutron to proton structure function ratio.Comment: revised version to appear in Phys. Rev. C; main modifications in Section 4; no change in the conclusion

    BB flavour tagging using charm decays at the LHCb experiment

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    An algorithm is described for tagging the flavour content at production of neutral BB mesons in the LHCb experiment. The algorithm exploits the correlation of the flavour of a BB meson with the charge of a reconstructed secondary charm hadron from the decay of the other bb hadron produced in the proton-proton collision. Charm hadron candidates are identified in a number of fully or partially reconstructed Cabibbo-favoured decay modes. The algorithm is calibrated on the self-tagged decay modes B+J/ψK+B^+ \to J/\psi \, K^+ and B0J/ψK0B^0 \to J/\psi \, K^{*0} using 3.0fb13.0\mathrm{\,fb}^{-1} of data collected by the LHCb experiment at pppp centre-of-mass energies of 7TeV7\mathrm{\,TeV} and 8TeV8\mathrm{\,TeV}. Its tagging power on these samples of BJ/ψXB \to J/\psi \, X decays is (0.30±0.01±0.01)%(0.30 \pm 0.01 \pm 0.01) \%.Comment: All figures and tables, along with any supplementary material and additional information, are available at http://lhcbproject.web.cern.ch/lhcbproject/Publications/LHCbProjectPublic/LHCb-PAPER-2015-027.htm

    Search for direct production of charginos and neutralinos in events with three leptons and missing transverse momentum in √s = 7 TeV pp collisions with the ATLAS detector

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    A search for the direct production of charginos and neutralinos in final states with three electrons or muons and missing transverse momentum is presented. The analysis is based on 4.7 fb−1 of proton–proton collision data delivered by the Large Hadron Collider and recorded with the ATLAS detector. Observations are consistent with Standard Model expectations in three signal regions that are either depleted or enriched in Z-boson decays. Upper limits at 95% confidence level are set in R-parity conserving phenomenological minimal supersymmetric models and in simplified models, significantly extending previous results

    Response of Wheat Fungal Diseases to Elevated Atmospheric CO2 Level

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    Infection with fungal pathogens on wheat varieties with different levels of resistance was tested at ambient (NC, 390 ppm) and elevated (EC, 750 ppm) atmospheric CO2 levels in the phytotron. EC was found to affect many aspects of the plant-pathogen interaction. Infection with most fungal diseases was usually found to be promoted by elevated CO2 level in susceptible varieties. Powdery mildew, leaf rust and stem rust produced more severe symptoms on plants of susceptible varieties, while resistant varieties were not infected even at EC. The penetration of Fusarium head blight (FHB) into the spike was delayed by EC in Mv Mambo, while it was unaffected in Mv Regiment and stimulated in Mv Emma. EC increased the propagation of FHB in Mv Mambo and Mv Emma. Enhanced resistance to the spread of Fusarium within the plant was only found in Mv Regiment, which has good resistance to penetration but poor resistance to the spread of FHB at NC. FHB infection was more severe at EC in two varieties, while the plants of Mv Regiment, which has the best field resistance at NC, did not exhibit a higher infection level at EC. The above results suggest that breeding for new resistant varieties will remain a useful means of preventing more severe infection in a future with higher atmospheric CO2 levels

    Evidence for the strangeness-changing weak decay ΞbΛb0π\Xi_b^-\to\Lambda_b^0\pi^-

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    Using a pppp collision data sample corresponding to an integrated luminosity of 3.0~fb1^{-1}, collected by the LHCb detector, we present the first search for the strangeness-changing weak decay ΞbΛb0π\Xi_b^-\to\Lambda_b^0\pi^-. No bb hadron decay of this type has been seen before. A signal for this decay, corresponding to a significance of 3.2 standard deviations, is reported. The relative rate is measured to be fΞbfΛb0B(ΞbΛb0π)=(5.7±1.80.9+0.8)×104{{f_{\Xi_b^-}}\over{f_{\Lambda_b^0}}}{\cal{B}}(\Xi_b^-\to\Lambda_b^0\pi^-) = (5.7\pm1.8^{+0.8}_{-0.9})\times10^{-4}, where fΞbf_{\Xi_b^-} and fΛb0f_{\Lambda_b^0} are the bΞbb\to\Xi_b^- and bΛb0b\to\Lambda_b^0 fragmentation fractions, and B(ΞbΛb0π){\cal{B}}(\Xi_b^-\to\Lambda_b^0\pi^-) is the branching fraction. Assuming fΞb/fΛb0f_{\Xi_b^-}/f_{\Lambda_b^0} is bounded between 0.1 and 0.3, the branching fraction B(ΞbΛb0π){\cal{B}}(\Xi_b^-\to\Lambda_b^0\pi^-) would lie in the range from (0.57±0.21)%(0.57\pm0.21)\% to (0.19±0.07)%(0.19\pm0.07)\%.Comment: 7 pages, 2 figures, All figures and tables, along with any supplementary material and additional information, are available at https://lhcbproject.web.cern.ch/lhcbproject/Publications/LHCbProjectPublic/LHCb-PAPER-2015-047.htm
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