Soil phosphorus dynamics as affected by Congo grass and P fertilizer

Some plant species can change soil phosphorus (P) availability and this may be an important tool in managing tropical high fixing phosphorus soils. An experiment was conducted to evaluate phosphorus transformations in the soil and phosphatase activity during periods of Congo grass (Brachiaria ruziziensis, Germain et Evrard) growth in two tropical soils receiving 20, 40, 80, 160 mg dm-3 of inorganic P. Plants were grown for 84 days in 8-L pots. Acid phosphatase activity, P in the microbial mass, soil organic and inorganic P and P accumulation by Congo grass were evaluated. Phosphorus fertilization increased soil P availability, Congo grass yields and P accumulation in the plant. On average, less labile P forms in the soil were not changed by Congo grass; however, the P in the soil extracted with HCl (P-Ca - non labil form) decreased. This decrease may have resulted from the combination of the presence of grass and phosphatase capacity to dissolve less available P in the soil. Thus, soil exploration by Congo grass roots and the subsequent extraction of calcium phosphate may have increased the P concentration in the plant tissue. Despite the decrease in the P extracted from the soil with HCl resulting in increased labile P forms in the soil, the effect of Congo grass on the availability of P depends on the soil type

On the Possibility of Superluminal Neutrino Propagation

We analyze the possibility of superluminal neutrino propagation delta v = (v - c)/c > 0 as indicated by OPERA data, in view of previous phenomenological constraints from supernova SN1987a and gravitational Cerenkov radiation. We argue that the SN1987a data rule out delta v ~ (E_\nu/M_N)^N for N \le 2 and exclude, in particular, a Lorentz-invariant interpretation in terms of a 'conventional' tachyonic neutrino. We present two toy Lorentz-violating theoretical models, one a Lifshitz-type fermion model with superluminality depending quadratically on energy, and the other a Lorentz-violating modification of a massless Abelian gauge theory with axial-vector couplings to fermions. In the presence of an appropriate background field, fermions may propagate superluminally or subluminally, depending inversely on energy, and on direction. Reconciling OPERA with SN1987a would require this background field to depend on location.Comment: 15 pages, replacement has an expanded and revised version of the second model; Notes added on how this model evades the Cohen-Glashow constraint

Effect of oxidizing and reducing atmospheres on Ba(Ti0.90Zr0.10)O3:2V ceramics as characterized by piezoresponse force microscopy

The effect of annealing atmospheres (At amb, N2 and O2) on the electrical properties of Ba(Ti0.90Zr0.10)O3:2V (BZT10:2V) ceramics obtained by the mixed oxide method was investigated. X-ray photoelectron spectroscopy (XPS) analysis indicates that oxygen vacancies present near Zr and Ti ions reduce ferroelectric properties, especially in samples treated in an ambient atmosphere (At amb). BZT10:2V ceramics sintered in a nitrogen atmosphere showed better dielectric behaviour at room temperature with a dielectric permittivity measured at a frequency of 10 kHz equal to 16800 with dielectric loss of 0.023. Piezoelectric force microscopy (PFM) images reveal improvement in the piezoelectric coefficient by sintering the sample under nitrogen atmosphere. Thus, BZT10:2V ceramics sintered under a nitrogen atmosphere can be useful for practical applications which include nonvolatile digital memories, spintronics and data-storage media

Strain behavior of lanthanum modified BiFeO3 thin films prepoared via soft chemical method

Pure and lanthanum modified BFO LaxBi1−xFeO3, x=0.0, 0.08, 0.15, 0.30 thin films were fabricated on Pt 111 /Ti/SiO2 / Si substrates by the soft chemical method. The effect of La substitution on the structural and electrical properties was studied. Scanning electron microscopy, x-ray diffraction, and Raman spectroscopy have been employed to characterize the thin films while the piezoelectric measurements were carried out using a setup based on an atomic force microscope. It was found that La-doped BFO thin films exhibited good ferroelectric properties, such as improved leakage current density and retention-free characteristics. The unipolar strain is strongly reduced by the amount of lanthanum added to the syste

Lurbinectedin in patients with pretreated neuroendocrine tumours: Results from a phase II basket study

Lurbinectedin; Neuroendocrine tumours; Small cellLurbinectedina; Tumores neuroendocrinos; Célula pequeñaLurbinectedina; Tumors neuroendocrins; Cèl·lula petitaBackground Patients with neuroendocrine tumours (NETs) need alternative therapies after failure of first-line therapy. Patients and methods This phase II trial evaluated lurbinectedin, a selective inhibitor of oncogenic transcription, at 3.2 mg/m2 as a 1-h intravenous infusion every 3 weeks in 32 NETs patients treated in the second- or third-line setting. The primary efficacy endpoint was overall response rate (ORR) according to RECIST v1.1 assessed by the investigators. Secondary endpoints included duration of response (DoR), progression-free survival (PFS), overall survival (OS) and safety. Results Two of 31 evaluable patients had confirmed partial responses (ORR = 6.5%; 95%CI, 0.8–21.4%). Median DoR was 4.7 months (95% CI, 4.0–5.4 months), median PFS was 1.4 months (95% CI, 1.2–3.0 months) and median OS was 7.4 months (95% CI, 3.4–16.2 months). Lurbinectedin showed an acceptable, predictable and manageable safety profile. The most common grade 3/4 toxicity was neutropenia (40.6%; grade 4, 12.4%; febrile neutropenia, 3.1%). Conclusions Considering the exploratory aim of this trial that evaluated a heterogeneous population of NETs patients, and the signs of antitumour activity observed (two confirmed partial responses and seven long disease stabilisations), further development of lurbinectedin is warranted in a more selected NETs population

Relationship between Crystal Shape, Photoluminescence, and Local Structure in SrTiO3 Synthesized by Microwave-Assisted Hydrothermal Method

This paper describes the effect of using different titanium precursors on the synthesis and physical properties of SrTiO3 powders obtained by microwave-assisted hydrothermal method. X-ray diffraction measurements, X-ray absorption near-edge structure (XANES) spectroscopy, field emission scanning electron microscopy (FE-SEM), and high-resolution transmission electron microscopy (HRTEM) were carried out to investigate the structural and optical properties of the SrTiO3 spherical and cubelike-shaped particles. The appropriate choice of the titanium precursor allowed the control of morphological and photoluminescence (PL) properties of SrTiO3 compound. The PL emission was more intense in SrTiO3 samples composed of spherelike particles. This behavior was attributed to the existence of a lower amount of defects due to the uniformity of the spherical particles

Low-temperature impedance spectroscopic analyses of ceramic electrodes based on Mo and Co co-doped SnO2

Low resistive electrodes based on Co and Mo co-doped SnO2 were prepared by the conventional solid-state reaction and sintered at 1250 °C for 2 h. Concentration of Co2O3 precursor was unchanged (1 mol%), while MoO3 was varied (0.25, 0.50 to 0.75 mol%) to promote conductivity. The structural and microstructural characterization revealed that the samples have a rutile-type structure without secondary phases and large rutile grains with low porosity. Electrical measurements on DC mode have shown a semiconductor behaviour of the SnO2 samples doped with 0.25 and 0.75 at. % of Mo at temperatures below 50 K, indicating their suitability for low-temperature electronic applications. Impedance measurements indicate reduced energy barriers of less than 1 meV formed between highly conductive crystallites for the SnO2 samples doped with 0.25 and 0.75 at. % of Mo. The sample with Mo content of 0.50 at. % presented a higher energy barrier at a few hundredths of eV, with space charges at the crystallite boundaries.Fil: Ferreira, Diego. Universidade Federal de Itajubá; BrasilFil: Vaz, Isabela. Universidade Federal de Itajubá; BrasilFil: Rubinger, Rero. Universidade Federal de Itajubá; BrasilFil: Buono, Camila. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones en Ciencia y Tecnología de Materiales. Universidad Nacional de Mar del Plata. Facultad de Ingeniería. Instituto de Investigaciones en Ciencia y Tecnología de Materiales; ArgentinaFil: Rocha, Leandro. Universidade Federal do São Carlos; BrasilFil: Ponce, Miguel Adolfo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones en Ciencia y Tecnología de Materiales. Universidad Nacional de Mar del Plata. Facultad de Ingeniería. Instituto de Investigaciones en Ciencia y Tecnología de Materiales; ArgentinaFil: Longo, Elson. Universidade Federal do São Carlos; BrasilFil: Simoes, Wilma Alexandre. Universidade Estadual Paulista Julio de Mesquita Filho; BrasilFil: Moura, Francisco. Universidade Federal de Itajubá; Brasi