Ferromagnetism and orbital order in a topological ferroelectric

We explore via density functional calculations the magnetic doping of a topological ferroelectric as an unconventional route to multiferroicity. Vanadium doping of the layered perovskite La$_{2}$Ti$_{2}$O$_{7}$ largely preserves electric polarization and produces robust ferromagnetic order, hence proper multiferroicity. The marked tendency of dopants to cluster into chains results in an insulating character at generic doping. Ferromagnetism stems from the symmetry breaking of the multi-orbital V system via an unusual "antiferro"-orbital order, and from the host's low-symmetry layered structure.Comment: 4 pages, 3 figures; Physical Review Letters 109, in print (2012

Divergent T-fO2 paths during crystallisation of H2O-rich and H2O-poor magmas as recorded by Ce and U in zircon, with implications for TitaniQ and TitaniZ geothermometry

During solidification of magma chambers as systems closed to chemical exchange with environs, the residual siliceous melt may follow a trend of rising, constant, or decreasing oxidation state, relative to reference buffers such as nickel + nickel oxide (NNO) or fayalite + magnetite + quartz. Titanomagnetite–hemoilmenite thermometry and oxybarometry on quenched volcanic suites yield temperature versus oxygen fugacity arrays of varied positive and negative slopes, the validity of which has been disputed for several years. We resolve the controversy by introducing a new recorder of magmatic redox evolution employing temperature- and redox-sensitive trace-element abundances in zircon. The zircon/melt partition coefficients of cerium and uranium vary oppositely in response to variation of magma redox state, but vary in tandem as temperature varies. Plots of U/Pr versus Ce4+/Ce3+ in zircon provide a robust test for change in oxidation state of the melt during zircon crystallisation from cooling magma, and the plots discriminate thermally induced from redox-induced variation of Ce4+/Ce3+ in zircon. Temperature-dependent lattice strain causes Ce4+/Ce3+ in zircon to increase strongly as zircon crystallises from cooling magma at constant Ce4+/Ce3+ ratio in the melt. We examine 19 zircon populations from igneous complexes in varied tectonic settings. Variation of zircon Ce4+/Ce3+ due to minor variation in melt oxidation state during crystallisation is resolvable in 11 cases but very subordinate to temperature dependence. In many zircon populations described in published literature, there is no resolvable change in redox state of the melt during tenfold variation of Ce4+/Ce3+ in zircons. Varied magmatic redox trends indicated by different slopes on plots of zircon U/Pr versus Ce4+/Ce3+ are corroborated by Fe–Ti-oxide-based T–ƒO2 trends of correspondingly varied slopes. Zircon and Fe–Ti-oxide compositions agree that exceptionally, H2O-rich arc magmas tend to follow a trend of rising oxidation state of the melt during late stages of fluid-saturated magmatic differentiation at upper-crustal pressures. We suggest that H2 and/or SO3 and/or Fe2+ loss from the melt to segregating fluid is largely responsible. Conversely, zircon and Fe–Ti-oxide compositions agree in indicating that H2O-poor magmas tend to follow a T–ƒO2 trend of decreasing oxidation state of the melt during late stages of magmatic differentiation at upper-crustal pressures, because the precipitating mineral assemblage has higher Fe3+/Fe2+ than coexisting rhyolitic melt. We present new evidence showing that the Fe–Ti-oxide oxybarometer calibration by Ghiorso and Evans (Am J Sci 308(9):957–1039, 2008) retrieves experimentally imposed values of ƒO2 in laboratory syntheses of Fe–Ti-oxide pairs to a precision of ± 0.2 log unit, over a large experimental temperature range, without systematic bias up to at least log ƒO2 ≈ NNO + 4.4. Their titanomagnetite–hemoilmenite geothermometer calibration has large systematic errors in application to Ti-poor oxides that precipitate from very oxidised magmas. A key outcome is validation of Fe–Ti-oxide-based values of melt TiO2 activity for use in Ti-in-zircon thermometry and Ti-in-quartz thermobarometry.We thank Paul Agnew and Alan Kobussen of Rio Tinto Exploration for financial support and for authorisation to publish research results. Additional financial support was provided by the ARC Centre of Excellence for Core to Crust Fluid Systems Grant CE110001017. MLF acknowledges the support of the Australian Research Council through the Future Fellowship Grant scheme (FT110100241). MLF also acknowledges support from the Australian Research Council through Linkage Project LP120100668. BDR acknowledges WMC Resources Ltd for financial support of his PhD research. RRL thanks the University of Bristol for a Benjamin Meaker Visiting Professorship which afforded an opportunity to clarify his understanding of this material through discussions with Professors Jon Blundy and Chris Hawkesworth

Evaluation of soil management effect on crop productivity and vegetation indices accuracy in mediterranean cereal-based cropping systems

none3noMostly, precision agriculture applications include the acquisition and elaboration of images, and it is fundamental to understand how farmers’ practices, such as soil management, affect those images and relate to the vegetation index. We investigated how long-term conservation agriculture practices, in comparison with conventional practices, can affect the yield components and the accuracy of five vegetation indexes. The experimental site is a part of a long-term experiment established in 1994 and is still ongoing that consists of a rainfed 2-year rotation with durum wheat and maize, where two unfertilized soil managements were repeated in the same plots every year. This study shows the superiority of no tillage over conventional tillage for both nutritional and productive aspects on durum wheat. The soil management affects the vegetation indexes’ accuracy, which is related to the nitrogen nutrition status. No-tillage management, which is characterized by a higher content of soil organic matter and nitrogen availability into the soil, allows obtaining a higher accuracy than the conventional tillage. So, the users of multispectral cameras for precision agriculture applications must take into account the soil management, organic matter, and nitrogen content.openOrsini R.; Fiorentini M.; Zenobi S.Orsini, R.; Fiorentini, M.; Zenobi, S

Beyond active site residues:overall structural dynamics control catalysis in flavin-containing and heme-containing monooxygenases

Monooxygenases (MOs) face the challenging reaction of an organic target, oxygen and a cofactor – most commonly heme or flavin. To correctly choreograph the substrates spatially and temporally, MOs evolved a variety of strategies, which involve structural flexibility. Besides classical domain and loop movements, flavin-containing MOs feature conformational changes of their flavin prosthetic group and their nicotinamide cofactor. With similar mechanisms emerging in various subclasses, their generality and involvement in selectivity are intriguing questions. Cytochrome P450 MOs are often inherently plastic and large movements of individual segments throughout the entire structure occur. As these complicated and often unpredictable movements are largely responsible for substrate uptake, engineering strategies for these enzymes were mostly successful when randomly mutating residues across the entire structure

Palliation with a multimodality treatment including hypoxic pelvic perfusion for unresectable recurrent rectal cancer: outcomes based on a retrospective study

Patients with unresectable recurrent rectal cancer that progresses after systemic chemotherapy and radiotherapy are candidates for palliation with hypoxic pelvic perfusion (HPP). The aim of this observational retrospective study was to evaluate if a multimodality treatment including HPP and targeted-therapy may be useful to prolong clinical responses and survival of these patients. From a cohort of 77 patients with unresectable recurrent rectal cancer in progression after standard treatments and submitted to HPP, 21 patients underwent repeat HPP using mitomycin C (MMC) at the dose of 25 mg/m2. After the last HPP, 7 patients received a targeted-therapy with cetuximab according to overexpression of epidermal growth factor receptor in recurrence cancer cells. The median overall survival of these 21 patients from the diagnosis of unresectable recurrent rectal cancer was 23 months (iqr 18-24). After the first HPP, the median survival of the 21 patients until death or end of follow-up was 10 months (iqr 9-13). The 1-year and 2-year survival rates were 71.4%, and 4.8%, respectively. From the first HPP, age\u2009>\u200960 years, a recurrence shrinkage of at least 30% (partial response), and the addition of a post-HPP targeted-therapy with cetuximab significantly affected survival (P\u2009<\u20090.04). In conclusion, repeated MMC-HPP followed by targeted-therapy seems to be an effective palliative treatment for patients with unresectable recurrent rectal cancer in progression after systemic chemotherapy and radiation but the results of this study have to be confirmed by a larger phase III trial

Acute coronary syndrome and renal impairment: a systematic review

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Reprint of “Investigating ensemble perception of emotions in autistic and typical children and adolescents”

Ensemble perception, the ability to assess automatically the summary of large amounts of information presented in visual scenes, is available early in typical development. This ability might be compromised in autistic children, who are thought to present limitations in maintaining summary statistics representations for the recent history of sensory input. Here we examined ensemble perception of facial emotional expressions in 35 autistic children, 30 age- and ability-matched typical children and 25 typical adults. Participants received three tasks: a) an ‘ensemble’ emotion discrimination task; b) a baseline (single-face) emotion discrimination task; and c) a facial expression identification task. Children performed worse than adults on all three tasks. Unexpectedly, autistic and typical children were, on average, indistinguishable in their precision and accuracy on all three tasks. Computational modelling suggested that, on average, autistic and typical children used ensemble-encoding strategies to a similar extent; but ensemble perception was related to non-verbal reasoning abilities in autistic but not in typical children. Eye-movement data also showed no group differences in the way children attended to the stimuli. Our combined findings suggest that the abilities of autistic and typical children for ensemble perception of emotions are comparable on average. Keywords: Ensemble perception, Autism, Summary statistics, Facial expressions, Emotion

hypoxia immunity metabolism and hyperthermia

Hypoxia is common in solid tumors and in many other disease states such as myocardial infarction, stroke, bone fracture, and pneumonitis. Once hypoxia has developed, the undernourished and hypoxic cells trigger signals in order to obtain new blood vessels to satisfy their increasing demands and to resolve hypoxia. The principal signal activated is an ancestral oxygen sensor, the hypoxia inducible factor (HIF). After its nuclear translocation, HIF triggers a series of mediators that recruit, into the hypoxic milieu, several immature myeloid, mesenchymal, and endothelial progenitors cells. Resident and recruited cells participate in the processes of neoangiogenesis, for resolving the hypoxia, while at the same time trigger an inflammatory reaction. The inflammatory reaction has as primary end point, the repair of the damaged area, but if an insufficient production of resolvins is produced, the inflammatory reaction becomes chronic and is unable to repair the damaged tissue. In this brief overview, we will show the differences and the similar events present in cancer, myocardial infarction, and stroke. Furthermore, the metabolic alterations produced in the tumor by hypoxia/HIF axis and the consequences on hyperthermic treatment are also discussed

Nitrogen and chlorophyll status determination in durum wheat as influenced by fertilization and soil management: Preliminary results.

Handheld chlorophyll meters as Soil Plant Analysis Development (SPAD) have proven to be useful tools for rapid, no-destructive assessment of chlorophyll and nitrogen status in various crops. This method is used to diagnose the need of nitrogen fertilization to improve the efficiency of the agricultural system and to minimize nitrogen losses and deficiency. The objective of this study is to evaluate the effect of repeated conservative agriculture practices on the SPAD readings, leaves chlorophyll concentration and Nitrogen Nutrition Index (NNI) relationships in durum wheat under Mediterranean conditions. The experimental site is a part of a long-term-experiment established in 1994 and is still on-going where three tillage managements and three nitrogen fertilizer treatments were repeated in the same plots every year. We observed a linear relationship between the SPAD readings performed in the central and distal portion of the leaf (R2 = 0.96). In fertilized durum wheat, we found all positive exponential relationships between SPAD readings, chlorophyll leaves concentration (R2 = 0.85) and NNI (R2 = 0.89). In the unfertilized treatment, the SPAD has a good attitude to estimate leaves chlorophyll concentration (R2 = 0.74) and NNI (R2 = 0.77) only in crop grow a soil with relative high content of soil organic matter and nitrogen availability, as observed in the no tilled plots. The results show that the SPAD can be used for a correct assessment of chlorophyll and nitrogen status in durum wheat but also to evaluate indirectly the content of soil organic matter and nitrogen availability during different growth stages of the crop cycle

Sulfur and Metal Fertilization of the Lower Continental Crust

Mantle-derived melts and metasomatic fluids are considered to be important in the transport and distribution of trace elements in the subcontinental lithospheric mantle. However, the mechanisms that facilitate sulfur and metal transfer from the upper mantle into the lower continental crust are poorly constrained. This study addresses this knowledge gap by examining a series of sulfide- and hydrous mineral-rich alkaline mafic-ultramafic pipes that intruded the lower continental crust of the Ivrea-Verbano Zone in the Italian Western Alps. The pipes are relatively small (<300 m diameter) and primarily composed of a matrix of subhedral to anhedral amphibole (pargasite), phlogopite and orthopyroxene that enclose sub-centimeter-sized grains of olivine. The 1 to 5 m wide rim portions of the pipes locally contain significant blebby and disseminated Fe-Ni-Cu-PGE sulfide mineralization.Stratigraphic relationships, mineral chemistry, geochemical modeling and phase equilibria suggest that the pipes represent open-ended conduits within a large magmatic plumbing system. The earliest formed pipe rocks were olivine-rich cumulates that reacted with hydrous melts to produce orthopyroxene, amphibole and phlogopite.Sulfides precipitated as immiscible liquid droplets that were retained within a matrix of silicate crystals and scavenged metals from the percolating hydrous melt. New high-precision chemical abrasion TIMS-UPb dating of zircons from one of the pipes indicates that these pipes were emplaced at 249.1+/-0.2 Ma, following partial melting of lithospheric mantle pods that were metasomatized during the Eo-Variscan oceanic to continental subduction (approx. 420-310 Ma). The thermal energy required to generate partial melting of the metasomatized mantle was most likely derived from crustal extension, lithospheric decompression and subsequent asthenospheric rise during the orogenic collapse of the Variscan belt (<300 Ma). Unlike previous models, outcomes from this study suggest a significant temporal gap between the occurrence of mantle metasomatism, subsequent partial melting and emplacement of the pipes.We argue that this multi-stage process is a very effective mechanism to fertilize the commonly dry and refractory lower continental crust in metals and volatiles. During the four-dimensional evolution of the thermo-tectonic architecture of any given terrain, metals and volatiles stored in the lower continental crust may become available as sources for subsequent ore-forming processes, thus enhancing the prospectivity of continental block margins for a wide range of mineral systems