104 resultados para Addition chains
Resumo:
We perform an extensive study of the properties of global quantum correlations in finite-size one-dimensional quantum spin models at finite temperature. By adopting a recently proposed measure for global quantum correlations (Rulli and Sarandy 2011 Phys. Rev. A 84 042109), called global discord, we show that critical points can be neatly detected even for many-body systems that are not in their ground state. We consider the transverse Ising model, the cluster-Ising model where three-body couplings compete with an Ising-like interaction, and the nearest-neighbor XX Hamiltonian in transverse magnetic field. These models embody our canonical examples showing the sensitivity of global quantum discord close to criticality. For the Ising model, we find a universal scaling of global discord with the critical exponents pertaining to the Ising universality class.
Resumo:
The autonomous pathway functions to promote flowering in Arabidopsis by limiting the accumulation of the floral repressor FLOWERING LOCUS C (FLC). Within this pathway FCA is a plant-specific, nuclear RNA-binding protein, which interacts with FY, a highly conserved eukaryotic polyadenylation factor. FCA and FY function to control polyadenylation site choice during processing of the FCA transcript. Null mutations in the yeast FY homologue Pfs2p are lethal. This raises the question as to whether these essential RNA processing functions are conserved in plants. Characterisation of an allelic series of fy mutations reveals that null alleles are embryo lethal. Furthermore, silencing of FY, but not FCA, is deleterious to growth in Nicotiana. The late-flowering fy alleles are hypomorphic and indicate a requirement for both intact FY WD repeats and the C-terminal domain in repression of FLC. The FY C-terminal domain binds FCA and in vitro assays demonstrate a requirement for both C-terminal FY-PPLPP repeats during this interaction. The expression domain of FY supports its roles in essential and flowering-time functions. Hence, FY may mediate both regulated and constitutive RNA 3'-end processing.
Resumo:
Two hundred eighty-five patients, median age 42, with PML-RARa-positive acute promyelocytic leukaemia were randomised to Ara-C-containing 'Medical Research Council (MRC) Chemotherapy'+ATRA (All-trans-retinoic acid) or anthracycline+ATRA (modified 'Spanish') therapy. MRC treatment comprised four courses with ATRA in courses 1-2. Spanish treatment comprised four anthracycline-based courses with ATRA in courses 1-3. In course 3 patients were randomised to gemtuzumab ozogamicin (GO) or not. The Spanish arm received 24-month maintenance. Patients were sequentially molecularly monitored. Quality of life was assessed at baseline, 3, 6, 9, 12, 24 months. Remission rates were similar in both arms (93%): cumulative incidence of haematological relapse (CIHR) was 6% at 5 years; 5 patients relapsed molecularly. Survival post relapse was 80%. There were more deaths in remission in the MRC arm (4% vs 10%: P=0.2). The overall 5-year relapse-free and overall survival was similar between arms (81% vs 82% and 84% vs 83%, respectively). More supportive care and hospitalisation (81.8 vs 63 days, P10 × 10(9)/l) was not prognostic overall, or within treatment arms. Both approaches deliver similar results with minor differences in quality of life. MRC treatment required more hospitalisation. This suggests that additional chemotherapy, Ara-C in particular, is not required.
Resumo:
The treatment of older patients with acute myeloid leukaemia, who are not considered suitable for conventional intensive therapy, is unsatisfactory. Low-dose Ara-C(LDAC) has been established as superior to best supportive care, but only benefits the few patients who enter complete remission. Alternative or additional treatments are required to improve the situation. This randomised trial compared the addition of the immunoconjugate, gemtuzumab ozogamicin (GO), at a dose of 5 mg on day 1 of each course of LDAC, with the intention of improving the remission rate and consequently survival. Between June 2004 and June 2010, 495 patients entered the randomisation. The addition of GO significantly improved the remission rate (30% vs 17%; odds ratio(OR) 0.48 (0.32-0.73); P=0.006), but not the 12 month overall survival (25% vs 27%). The reason for the induction benefit failing to improve OS was two-fold: survival of patients in the LDAC arm who did not enter remission and survival after relapse were both superior in the LDAC arm. Although the addition of GO to LDAC doubled the remission rate it did not improve overall survival. Maintaining remission in older patients remains elusive.
Resumo:
The aqueous phase reforming (APR) of xylitol was studied in a continuous fixed bed reactor over three catalysts: Pt/Al2O3, Pt/TiO2 and Pt-Re/TiO2. The data obtained in the case of the monometallic Pt catalysts was compared to the bimetallic Pt-Re sample. The effect of Re addition on the catalyst stability, activity, product formation and selectivity toward hydrogen and alkanes was studied. The bimetallic catalyst demonstrated a higher selectivity to alkanes compared to the monometallic samples. The monometallic catalyst was more selective toward hydrogen formation. A plausible reaction scheme explaining differences in selectivity toward hydrogen and alkanes was proposed and discussed.
Resumo:
This laboratory experiment systematically examines arsenic, iron, and phosphorus solubilities in soil suspensions as affected by addition of phosphorus fertilizer under different redox potential (Eh) and pH conditions. Under aerobic conditions, As solubility was low, however, under moderately reducing conditions (0, -150 mV), As solubility significantly increased due to dissolution of iron oxy-hydroxides. Upon reduction to -250 mV, As solubility was controlled by the formation of insoluble sulfides, and as a result soluble As contents significantly decreased. Soluble Fe concentration increased from moderate to highly anaerobic conditions; however, it decreased under aerobic conditions likely due to formation of insoluble oxy-hydroxides. A low pH, 5.5, led to increased soluble concentrations of As, Fe, and P. Finally, addition of P-fertilizers resulted in higher soluble P and As, even though the concentration of As did not increased after an addition rate of 600 mg P kg(-1) soil. (c) 2006 Elsevier B.V. All rights reserved.
Resumo:
Conjugated polymers have attracted considerable attention in the last few decades due to their potential for optoelectronic applications. A key step that needs optimisation is charge carrier separation following photoexcitation. To understand better the dynamics of the exciton prior to charge separation, we have performed simulations of the formation and dynamics of localised excitations in single conjugated polymer strands. We use a nonadiabatic molecular dynamics method which allows for the coupled evolution of the nuclear degrees of freedom and of multiconfigurational electronic wavefunctions. We show the relaxation of electron-hole pairs to form excitons and oppositely charged polaron pairs and discuss the modifications to the relaxation process predicted by the inclusion of the Coulomb interaction between the carriers. The issue of charge photogeneration in conjugated polymers in dilute solution is also addressed. (C) 2011 American Institute of Physics. [doi: 10.1063/1.3600404]
Resumo:
In order to combine the mechanical properties of yttria-stabilised zirconia (ZrO2-3 mol% Y2O3; code Y-ZrO2) with the bioactivity of titania (TiO2), Y-ZrO2-TiO2, green compacts with 0-40vol.% TiO2 were sintered at 1300, 1400, and 1500degreesC for 4h, respectively. The microstructural features such as grains, pores, and phases were examined using scanning electron microscopy (SEM), X-ray diffraction (XRD), and energy dispersive spectroscopy (EDX). The mechanical properties such as hardness and toughness were also determined using the methods of Vickers indentation and Knoop indentation. All the composites showed the major tetragonal Y-ZrO2 phase regardless of the content of the added TiO2. However, rutile TiO2 phase was obtained at 1300degreesC, whereas zirconium titanate (ZrTi04) phase was found at 1400 and 1500degreesC. The Y-ZrO2-ZrTiO4 Composites sintered at 1500degreesC showed relatively high hardness (860-1000 kg/mm(2)) and toughness (4.0-4.5 MPa m(0.5)), whereas the Y-ZrO2-TiO2 composites sintered at 1300degreesC had slightly lower hardness (720-950kg/mm(2)) and fracture toughness (3.1-3.3 MPa m(0.5)). (C) 2004 Elsevier Ltd and Techna Group S.r.l. All rights reserved.
Resumo:
Tunnel construction planning requires careful consideration of the spoil management part, as this involves environmental, economic and legal requirements. In this paper a methodological approach that considers the interaction between technical and geological factors in determining the features of the resulting muck is proposed. This gives indications about the required treatments as well as laboratory and field characterisation tests to be performed to assess muck recovery alternatives. While this reuse is an opportunity for excavations in good quality homogeneous grounds (e.g. granitic mass), it is critical for complex formation. This approach has been validated, at present, for three different geo-materials resulting from a tunnel excavation carried out with a large diameter Earth Pressure Balance Shield (EPB) through a complex geological succession. Physical parameters and technological features of the three materials have been assessed, according to their valorisation potential, for defining re-utilisation patterns. The methodology proved to be effective and the laboratory tests carried out on the three materials allowed the suitability and treatment effectiveness for each muck recovery strategy to be defined. © 2014 Elsevier Ltd.