Composts de residuos de caña de azúcar. Capacidad de cesión de boro a la planta

A greenhouse experiment was carried out to determine the capacity of three different composts to release boron gradually to a ryegrass crop. The three composts were made up using the following agricultural wastes: compost BO: 75% sugarcane bagasse, 17% orugo cake and 8% hen manure; compost BG: 78% bagas se and 22% hen manure and compost BT: 95% bagasse and 5% tobacco dust. The composts made up of sugarcane bagasse plus tobacco dust was more effective in releasing boron to the plant than bagasse mixed with orugo and/or hen manure composts. With respect to the form of B release, compost BO did it gradually, compost BG after a long period of integration in the soil and compost BT immediately, during the initial phase of the experiment.Se ha llevado a cabo un experimento de invernadero dedicado a valorar la capacidad que poseen tres composts para suministrar secuencialmente boro a un cultivo de ryegrass. Los composts se prepararon utilizando los siguientes residuos agrícolas: compost BO: 75% residuo de caña de azucar (bagazo), 17% orujo y 7% gallinaza; compost BG: 78% bagazo y 22% gallinaza y compost BT: 95% bagazo y 5% residuo de tabaco. El compost obtenido a partir de bagazo y residuo de tabaco fue mas eficaz para suministrar boro a la planta que los composts que incluían bagazo y orujo y/o gallinaza. Respecto a la forma de cesión de B, el compost BO lo suministró gradualmente,· el compost BG tras un largo período de integración en el suelo y el compost BT inmediatamente, al inicio del experimento

Composts de residuos de caña de azúcar. Capacidad de cesión de boro a la planta

A greenhouse experiment was carri ed out to determi ne the capacity of three different composts to re 1 ease boron gradua 11y to a ryegrass crop. The three composts were made up using the fo110wing agricu1tural wastes: compost BO: 75% sugarcane bagasse, 17% orugo cake and 8% hen manure; compost BG: 78% bagas se and 22% hen manure and compost BT: 95% bagasse and 5% tobacco dust. The composts made up of sugarcane bagasse plus tobacco dust was more effective in re1easing boron to the p1ant than bagasse mixed with orugo and/or hen manure composts. With respect to the form of B re1ease, compost BO did it gradua11y, compost BG after a long period of integration in the soil and compost BT immediate1y, during the initia1 phase of the experimentoSe ha llevado a cabo un experimento de invernadero dedicado a valorar la capa cidad que poseen tres composts para suministrar secuencialmente boro a un cul tivo de ryegrass. Los composts se prepararon utilizando los siguientes resf duos agrícolas: compost BO: 75% resfduo de caña de azucar (bagazo), 17% orujo y 7% ga 11 i naza; compost BG: 78% bagazo y 22% ga 11 i naza y compost BT: 95% ba gazo y 5% resíduo de tabaco. El compost obtenido a partir de bagazo y residuo de tabaco fué mas eficaz para suministrar boro a la planta que los composts que incluían bagazo y orujo y/o gallinaza. Respecto a la forma de cesión de B, el compost BO 10 suministró gradua1mente,·e1 compost BG tras un largo perío do de integración en el suelo y el compost BT inmediatamente, al inicio deT experimento

Scaling properties of the critical behavior in the dilute antiferromagnet Fe(0.93)Zn(0.07)F2

Critical scattering analyses for dilute antiferromagnets are made difficult by the lack of predicted theoretical line shapes beyond mean-field models. Nevertheless, with the use of some general scaling assumptions we have developed a procedure by which we can analyze the equilibrium critical scattering in these systems for H=0, the random-exchange Ising model, and, more importantly, for H>0, the random-field Ising model. Our new fitting approach, as opposed to the more conventional techniques, allows us to obtain the universal critical behavior exponents and amplitude ratios as well as the critical line shapes. We discuss the technique as applied to Fe(0.93)Zn(0.07)F2. The general technique, however, should be applicable to other problems where the scattering line shapes are not well understood but scaling is expected to hold.Comment: 17 pages, 5 figure

Anomalous ferromagnetic spin fluctuations in an antiferromagnetic insulator Pr_{1-x}Ca_{x}MnO_{3}

The high temperature paramagnetic state in an antiferromagnetic (AFM) insulator Pr_{1-x}Ca_{x}MnO_{3} is characterized by the ferromagnetic (FM) spin fluctuations with an anomalously small energy scale. The FM fluctuations show a precipitous decrease of the intensity at the charge ordering temperature T_{CO}, but persist below T_{CO}, and vanish at the AFM transition temperature T_{N}. These results demonstrate the importance of the spin ordering for the complete switching of the FM fluctuation in doped manganites.Comment: REVTeX, 5 pages, 4 figures, submitted to Phys. Rev.

Magnon Damping by magnon-phonon coupling in Manganese Perovskites

Inelastic neutron scattering was used to systematically investigate the spin-wave excitations (magnons) in ferromagnetic manganese perovskites. In spite of the large differences in the Curie temperatures ($T_C$s) of different manganites, their low-temperature spin waves were found to have very similar dispersions with the zone boundary magnon softening. From the wavevector dependence of the magnon lifetime effects and its correlation with the dispersions of the optical phonon modes, we argue that a strong magneto-elastic coupling is responsible for the observed low temperature anomalous spin dynamical behavior of the manganites.Comment: 11 pages, 4 figure

A Theory of Magnets with Competing Double Exchange and Superexchange Interactions

We study the competition between ferromagnetic double exchange (DE) and nearest-neighbour antiferromagnetic exchange in CMR materials. Towards this end, a single site mean field theory is proposed which emphasizes the hopping-mediated nature of the DE contribution. We find that the competition between these two exchange interactions leads to ferro- or antiferromagnetic order with incomplete saturation of the (sub)lattice magnetization. This conclusion is in contrast to previous results in the literature which find a canted spin arrangement under similar circumstances. We attribute this difference to the highly anisotropic exchange interactions used elsewhere. The associated experimental implications are discussed.Comment: 4 pages, Latex-Revtex, 3 PostScript figures. Please see report cond-mat/980523

The enduring value of reciprocal illumination in the era of insect phylogenomics: a response to Cai et al. (2020)

Arguably no other group within Coleoptera has received as robust and sustained investigation into their phylogenetic relationships as aquatic beetles. Among this ecological guild, evolutionary relationships of the families within Dytiscoidea, a clade comprising the charismatic diving beetles (Dytiscidae) and their close relatives, have received particular attention. Very recently, four different studies were published investigating the phylogeny of Dytiscoidea, three of which utilized phylogenomic data, the most recent by Cai etal. (2020). Cai et al. (2020) (hereafter CEA) approached investigating theevolutionary relationships among dytiscoid families by reanalysing the transcriptomic dataset of Vasilikopoulos et al. (2019) using different evolutionary models and data trimming regimes. CEAs analyses recovered three different topologies for relationships amongst Dytiscoidea, two of which have been recovered in several previous studies. The primary difference among these topologies is the placement of Hygrobiidae, either as sister to (Dytiscidae (Amphizoidae + Aspidytidae)), sister to Amphizoidae + Aspidytidae, or as sister to Dytiscidae. In CEA, topologies shown in Fig. 1A, C both received maximal (e.g. bootstrap values of 100 and posterior probabilities of 100%) to strong support respectively via their preferred model of evolution. Whereas CEAs recovery of Hygrobiidae sister to Amphizoidae + Aspidytidae was not as strongly supported, Gustafson et al. (2020) recovered this topology primarily with strong to maximal support across all analyses with comprehensive taxon sampling of Dytiscoidea. Rather than treating the three topologies recovered both within their own study and elsewhere as equally viable hypotheses, CEA dismissed the relationships shown in Fig. 1A, B as the result of phylogenetic methodological error, promoting Fig. 1C as their preferred tree because it is consistent with morphology-based views of dytiscoid relationships. Here, we address (i) the manner in which CEA approached reconciling conflicting hypotheses about the evolution of Dytiscoidea; and (ii) the misconception that dytiscoid relationships shown in Fig. 1C are the most consistent with morphology-based views in relation to those of Fig. 1A, B.Fil: Gustafson, Grey T.. University of Kansas; Estados UnidosFil: Miller, Kelly B.. University of New Mexico. Department of Biology; Estados UnidosFil: Michat, Mariano Cruz. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Biodiversidad y Biología Experimental y Aplicada. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Biodiversidad y Biología Experimental y Aplicada; ArgentinaFil: Alarie, Yves. Laurentian University. Department of Biology; CanadáFil: Baca, Stephen M.. University of Kansas; Estados UnidosFil: Balke, Michael. Zoologische Staatssammlung Munchen; AlemaniaFil: Short, Andrew E. Z.. University of Kansas; Estados Unido

Soft spin waves in the low temperature thermodynamics of Pr_{0.7}Ca_{0.3}MnO_{3}

We present a detailed magnetothermal study of Pr(0.7)Ca(0.3)MnO(3), a perovskite manganite in which an insulator-metal transition can be driven by magnetic field, but also by pressure, visible light, x-rays, or high currents. We find that the field-induced transition is associated with an enormous release of energy which accounts for its strong irreversibility. In the ferromagnetic metallic state, specific heat and magnetization measurements indicate a much smaller spin wave stiffness than that seen in any other manganite, which we attribute to spin waves among the ferromagnetically ordered Pr moments. The coupling between the Pr and Mn spins may also provide a basis for understanding the low temperature phase diagram of this most unusual manganite.Comment: 10 pages, LATEX, 5 PDF figures, corrected typo