Sharp values for the constants in the polynomial Bohnenblust-Hille inequality

In this paper we prove that the complex polynomial Bohnenblust-Hille constant for $2$-homogeneous polynomials in ${\mathbb C}^2$ is exactly $\sqrt[4]{\frac{3}{2}}$. We also give the exact value of the real polynomial Bohnenblust-Hille constant for $2$-homogeneous polynomials in ${\mathbb R}^2$. Finally, we provide lower estimates for the real polynomial Bohnenblust-Hille constant for polynomials in ${\mathbb R}^2$ of higher degrees.Comment: 16 page

Disentangling the jet emission from protostellar systems. The ALMA view of VLA1623

Context: High-resolution studies of class 0 protostars represent the key to constraining protostar formation models. VLA16234-2417 represents the prototype of class 0 protostars, and it has been recently identified as a triple non-coeval system. Aim: We aim at deriving the physical properties of the jets in VLA16234-2417 using tracers of shocked gas. Methods: ALMA Cycle 0 Early Science observations of CO(2-1) in the extended configuration are presented in comparison with previous SMA CO(3-2) and Herschel-PACS [OI}] 63 micron observations. Gas morphology and kinematics were analysed to constrain the physical structure and origin of the protostellar outflows. Results: We reveal a collimated jet component associated with the [OI] 63 micron emission at about 8'' (about 960 AU) from source B. This newly detected jet component is inversely oriented with respect to the large-scale outflow driven by source A, and it is aligned with compact and fast jet emission very close to source B (about 0.3'') rather than with the direction perpendicular to the A disk. We also detect a cavity-like structure at low projected velocities, which surrounds the [OI] 63 micron emission and is possibly associated with the outflow driven by source A. Finally, no compact outflow emission is associated with source W. Conclusions: Our high-resolution ALMA observations seem to suggest there is a fast and collimated jet component associated with source B. This scenario would confirm that source B is younger than A, that it is in a very early stage of evolution, and that it drives a faster, more collimated, and more compact jet with respect to the large-scale slower outflow driven by A. However, a different scenario of a precessing jet driven by A cannot be firmly excluded from the present observations.Comment: Accepted for publication in Astronomy & Astrophysic

Halophyte common ice plants: A future solution to arable land salinization

The problems associated with the salinization of soils and water bodies and the increasing competition for scarce freshwater resources are increasing. Current attempts to adapt to these conditions through sustainable agriculture involves searching for new highly salt-tolerant crops, and wild species that have potential as saline crops are particularly suitable. The common ice plant (Mesembryanthemum crystallinum L.) is an edible halophyte member of the Aizoaceae family, which switches from C3 photosynthesis to crassulacean acid metabolism (CAM) when exposed to salinity or water stress. The aim of this review was to examine the potential of using the ice plant in both the wild and as a crop, and to describe its ecology and morphology, environmental and agronomic requirements, and physiology. The antioxidant properties and mineral composition of the ice plant are also beneficial to human health and have been extensively examined

A generic tool for interactive complex image editing

Plenty of complex image editing techniques require certain per-pixel property or magnitude to be known, e.g., simulating depth of field effects requires a depth map. This work presents an efficient interaction paradigm that approximates any per-pixel magnitude from a few user strokes by propagating the sparse user input to each pixel of the image. The propagation scheme is based on a linear least-squares system of equations which represents local and neighboring restrictions over superpixels. After each user input, the system responds immediately, propagating the values and applying the corresponding filter. Our interaction paradigm is generic, enabling image editing applications to run at interactive rates by changing just the image processing algorithm, but keeping our proposed propagation scheme. We illustrate this through three interactive applications: depth of field simulation, dehazing and tone mapping

Tolerance of Pedunculate oak (Quercus robur) saplings to herbicides

Spraying herbicides to reduce weed competition is a usual practice in agricultural regions. However, tree tending under agroforestry or forest plantations is hampered by the extensive use of these pesticides. Here, we assessed the survival, symptoms expression and growth of pedunculate oak (Quercus robur) saplings after spraying different herbicides at recommended doses in two seasons: winter and spring. Three independent herbicide trials were carried out on oak sapling plots (E_WINTER 2013, E_SPRING 2012, E_SPRING 2013) in Ayacucho, province of Buenos Aires, Argentina. Plants were kept under uniform conditions in a nursery for about three months. We alternatively tested the herbicides (doses in sub-index, cc.ha-1 or g.ha-1) flumioxazin (FLUM100), glyphosate (GLIF2000, 4000, 6000), metsulfuron-methyl (METS8), dicamba (DIC120), propaquizafop (PROP500, 1000), flurochloridone (FLUO1000, 1500, 4000), atrazine (ATR2000, 4000), acetochlor (ACET2000), imazethapyr (IMAZE500, 1000) and imazapyr (IMAZA33, 100). At the end of each trial all plants survived, regardless of treatment, although the symptoms varied depending on the trial and product. Glyphosate associated with chlorosis, necrosis and deformation, propaquizafop with necrosis, and dicamba, flurochloridone, imazethapyr and imazapyr with chlorosis. ATR2000 and FLUO1500 treatments advanced the re-sprout phases. In terms of growth, saplings sprayed with IMAZE1000, IMAZA100 and GLIF6000 had lower total dry weight than the control (CT) (p<0.05), in E_SPRING 2012. In E_WINTER 2013 differences of dry weight were not significant, but in E_SPRING 2013, FLUO1500 sprayed saplings had a lower dry weight of roots than CT (p<0.05). Total plant height and stem diameter presented similar trends. According to the whole set of symptoms assessed, the application of FLUM100, ACET2000, ATR2000 or METS8 would be compatible with oak saplings production. The low effect of herbicides in wintertime might be related to different ways of avoidance to herbicide penetration: root depth, the absence of foliage or to the protective structure of buds (perulae); in spring, to root depth, leaf cuticle thickness and hairiness, and to the (high) capacity of the oaks to re-sprout. Although the results obtained are promising for oak plantation in sites exposed to common herbicides, further research is needed to assess long term responses, or to repeated applications over time.El uso de herbicidas en áreas agrícolas es una práctica usual para reducir la competencia de malezas. Sin embargo, la plantación de árboles en sistemas agroforestales o en macizos es amenazada por la aplicación extensiva de estos agroquímicos. En este estudio se evaluó supervivencia, síntomas y crecimiento inicial de plantines de roble pedunculado (Quercus robur) tratados con distintos herbicidas bajo las dosis usualmente recomendadas y en dos épocas del año: invierno y primavera. Con este fin se llevaron a cabo tres ensayos independientes sobre plantines de roble (E_WINTER 2013, E_SPRING 2012, E_SPRING 2013) en la localidad de Ayacucho, provincia de Buenos Aires, Argentina. Las plantas se mantuvieron en el vivero durante aproximadamente tres meses bajo condiciones uniformes. Se probaron alternativamente los herbicidas (dosis en subíndices, en cc.ha-1 o g.ha-1): flumioxazin (FLUM100), glifosato, (GLIF2000, 4000, 6000), metsulfuronmetil (METS8), dicamba (DIC120), propaquizafop (PROP500, 1000), flurocloridona (FLUO1000, 1500, 4000), atrazina (ATR2000, 4000), acetoclor (ACET2000), imazetapir (IMAZE500, 1000) e imazapir (IMAZA33, 100). Al finalizar los ensayos todas las plantas sobrevivieron, independientemente de los tratamientos, aunque los síntomas variaron según los ensayos y productos aplicados. El glifosato se asoció con clorosis, necrosis y deformación de las hojas, propaquizafop con necrosis, y dicamba, fluorocloridona, imazetapir e imazapir con clorosis. Los tratamientos ATR2000 y FLUO1500 adelantaron las fases de rebrote. En cuanto al crecimiento, los plantines tratados con IMAZE1000, IMAZA100 y GLIF6000 alcanzaron un menor peso seco total que el control (CT) (p<0.05) en el ensayo E_SPRING 2012. En el ensayo E_WINTER 2013 no se observaron diferencias significativas en el peso seco, pero en E_SPRING 2013, con FLUO1500 los plantines alcanzaron menor peso seco de raíces que el control (p<0.05). Las alturas totales y los diámetros de tallo presentaron tendencias similares. Según los síntomas observados en el total de los ensayos, FLUM100, ACET2000, ATR2000 y METS8 serían compatibles con los plantines de roble. Los modos de evadir la penetración de los herbicidas en el período invernal pueden relacionarse con la profundidad de las raíces, con la ausencia de hojas y con la protección de las yemas por pérulas; y en la primavera con la profundidad de las raíces, con el espesor de la cutícula y con la pilosidad foliar, y con la alta capacidad de rebrote de los robles. Si bien los resultados alcanzados son promisorios para la implantación de robles en sitios expuestos a herbicidas de uso corriente, es necesario conducir otros estudios para evaluar la reacción de las plantas a largo plazo, o sujetas a aplicaciones repetidas en el tiempo.EEA BalcarceFil: Laclau, Pablo. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Balcarce. Agencia de Extensión Rural Tandil; ArgentinaFil: Murillo, Natalia Lorena. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Balcarce. Agencia de Extensión Rural Nicanor Otamendi; ArgentinaFil: Bertoli, B. Vivero Bértoli; ArgentinaFil: Vignolio, Osvaldo. Universidad Nacional de Mar del Plata. Facultad de Ciencias Agrarias. Unidad Integrada. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Balcarce; Argentina

Chemocatalysis of sugars to produce lactic acid derivatives on zeolitic imidazolate frameworks

Several research studies related to biorefining have focused on developing routes for biomass conversion into biomaterials or platform molecules. In this work, the zeolitic imidazolate frameworks (ZIFs) ZIF-8 and ZIF-67 have been tested as catalysts in the conversion of sugars (sucrose, glucose and fructose) into methyl lactate. ZIF-8 and ZIF-67 have the same sodalite type zeolite structure but behaved differently in the sugar conversion in methanol due to the respective presence of Zn and Co in their structures. ZIF-8 has been found to be the most active for the conversion of sugars into methyl lactate (yield 42%) and was reused in four catalytic cycles. The chemical and physical effects caused by these cycles on the catalysts have been studied by several techniques (X-ray diffraction, thermogravimetric analyses, infrared spectroscopy, X-ray photoelectron spectroscopy, scanning electronic microscopy and nitrogen adsorption)