Multiple Context-Free Tree Grammars: Lexicalization and Characterization

Multiple (simple) context-free tree grammars are investigated, where "simple" means "linear and nondeleting". Every multiple context-free tree grammar that is finitely ambiguous can be lexicalized; i.e., it can be transformed into an equivalent one (generating the same tree language) in which each rule of the grammar contains a lexical symbol. Due to this transformation, the rank of the nonterminals increases at most by 1, and the multiplicity (or fan-out) of the grammar increases at most by the maximal rank of the lexical symbols; in particular, the multiplicity does not increase when all lexical symbols have rank 0. Multiple context-free tree grammars have the same tree generating power as multi-component tree adjoining grammars (provided the latter can use a root-marker). Moreover, every multi-component tree adjoining grammar that is finitely ambiguous can be lexicalized. Multiple context-free tree grammars have the same string generating power as multiple context-free (string) grammars and polynomial time parsing algorithms. A tree language can be generated by a multiple context-free tree grammar if and only if it is the image of a regular tree language under a deterministic finite-copying macro tree transducer. Multiple context-free tree grammars can be used as a synchronous translation device.Comment: 78 pages, 13 figure

Efecto de la vacunación contra el virus de la fiebre aftosa sobre la pérdida de preñez en un rodeo de bovinos para carne

Se realizó un estudio para evaluar el efecto de la vacunación contra el virus de la fiebre aftosa (FA), aplicada durante el periodo embrionario, sobre la pérdida de preñez en un rodeo de vacas Angus que habían sido inseminadas artificialmente a tiempo fijo (IATF). Treinta y dos días post IATF se realizó el diagnóstico de gestación. Doscientas noventa y tres hembras preñadas (vaquillonas, n = 108, vacas primíparas, n = 88 y vacas multíparas, n = 97) fueron asignadas al azar a uno de dos tratamientos: vacunadas (VAC; n = 147) contra el virus de FA a los 32 días post IATF, y sin vacunar (NOVAC; n = 146). Sesenta días post IATF se realizó un segundo diagnóstico de gestación y se cuantificó la pérdida de preñez. No se observaron diferencias significativas (P = 0,78) en el porcentaje de pérdida de preñez entre los 32 y 60 días post IATF entre VAC (4,76%) y NOVAC (5,48%). Bajo las condiciones del presente estudio, la aplicación de la vacuna contra el virus de la FA a los 32 días de gestación no tuvo efecto en la pérdida de preñez en bovinos Angus.A study was conducted to evaluate the effect of foot-and-mouth disease (FMD) virus vaccination, applied during the embryonic period, on pregnancy loss of Angus cows pregnant by fixed-time artificial insemination (FTAI). Thirty-two days after FTAI pregnancy diagnosis was carried out. Two hundred ninety three pregnant cattle (heifers, n = 108, primiparous cows, n = 88 and multiparous cows, n = 97) were randomly assigned to one of two treatments: FMD vaccinated (VAC, n = 147) at 32 days after FTAI, and without vaccinating (NOVAC, n = 146). Sixty days after FTAI pregnancy diagnosis was carried out in order to quantify pregnancy losses. No significant differences (P = 0.78) in the percentage of pregnancy losses between 32 and 60 days after fixedtime AI between VAC (4.76%) and NOVAC (5.48%) were observed. Under the conditions of the present study, the application of FMD vaccination at 32 days of gestation had no effect on pregnancy loss in Angus cattle.EEA Cuenca del SaladoFil: Rodriguez, Alejandro Martin. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Cuenca del Salado; ArgentinaFil: Guzman, Cesar Federico. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Cuenca del Salado; ArgentinaFil: Lopez Valiente, Sebastian. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Cuenca del Salado; ArgentinaFil: Maletti, Ernesto Juan. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Cuenca del Salado; ArgentinaFil: Canton, German Jose. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Balcarce; ArgentinaFil: Maresca, Sebastian. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Cuenca del Salado; Argentin

Structural Aspects of P2-Type Na0.67Mn0.6Ni0.2Li0.2O2 (MNL) Stabilization by Lithium Defects as a Cathode Material for Sodium-Ion Batteries

A known strategy for improving the properties of layered oxide electrodes in sodium-ion batteries is the partial substitution of transition metals by Li. Herein, the role of Li as a defect and its impact on sodium storage in P2-Na0.67Mn0.6Ni0.2Li0.2O2 is discussed. In tandem with electrochemical studies, the electronic and atomic structure are studied using solid-state NMR, operando XRD, and density functional theory (DFT). For the as-synthesized material, Li is located in comparable amounts within the sodium and the transition metal oxide (TMO) layers. Desodiation leads to a redistribution of Li ions within the crystal lattice. During charging, Li ions from the Na layer first migrate to the TMO layer before reversing their course at low Na contents. There is little change in the lattice parameters during charging/discharging, indicating stabilization of the P2 structure. This leads to a solid-solution type storage mechanism (sloping voltage profile) and hence excellent cycle life with a capacity of 110 mAh g-1 after 100 cycles. In contrast, the Li-free compositions Na0.67Mn0.6Ni0.4O2 and Na0.67Mn0.8Ni0.2O2 show phase transitions and a stair-case voltage profile. The capacity is found to originate from mainly Ni3+/Ni4+ and O2-/O2-δ redox processes by DFT, although a small contribution from Mn4+/Mn5+ to the capacity cannot be excluded. © 2021 The Authors. Advanced Functional Materials published by Wiley-VCH Gmb

Comparison of Layered Li(Li0.2_{0.2}Rh0.8_{0.8})O2_{2} and LiRhO2_{2} upon Li Removal: Stabilizing Effect of Li Substitution

Phase transformations upon delithiation in layered oxides with the NaCrS$_{2}$ structure type are widely studied for numerous combinations of 3d transition metals because of the application of LiCoO$_{2}$ and its derivatives as cathode materials in rechargeable Li-ion batteries. However, complete replacement of 3d by 4d transition metals still yields phenomena never seen in compounds containing 3d metals only. In the present work, the structural evolution of Li-rich O$_{3}$–Li(Li$_{0.2}$Rh$_{0.8}$)O$_2$, having a mixed occupancy of 20% Li and 80% Rh in the metal–O slabs, was studied during electrochemical Li removal and insertion and compared with the isostructural stoichiometric LiRhO$_{2}$. The latter compound undergoes a transformation from the layered NaCrS$_{2}$ to the tunnel-like rutile–ramsdellite intergrowth structure of the γ-MnO$_{2}$ type. Partial replacement of Rh by Li, in contrast, completely prevents this transition, resulting in a reversible cell expansion and shrinkage within the layered structure upon (de)lithiation. Moreover, no anomalously short Rh–O and O–O distances were observed in Li$_{x≈0}$(Li$_{0.2}$Rh$_{0.8}$)O$_{2}$ with the Rh$^{4.75+}$ intermediate valence state at 4.8 V, in contrast to Lii$_{x≈0}$RhO$_{2}$ with Rh$^{4+ }$ at 4.2 V, as confirmed by operando synchrotron X-ray diffraction and extended X-ray absorption fine structure studies. We believe that the difference in the Li–O and Rh–O covalency is responsible for the observed structural stabilization. The longer and more ionic Li–O bonds in the (Li,Rh)O$_{2}$ laye rs impede the shortening of O–O distances needed for transformation to the γ-MnOi$_{2}$type because of a higher negative charge on O anions connected to Li cations and the stronger electrostatic repulsion between them

Resultados a mediano plazo de la prótesis abisagrada rotatoria en el reemplazo total de rodilla primario y de revisión

Objective: To analyze the clinical and radiological mid-term outcomes of 34 rotating-hinge total knee arthroplasties. Materials and Methods: We studied 34 hinge knee prostheses. The arthroplasty indication was in the setting of primary surgery for 10 patients (29.5%) and in the setting of revision for 24 patients (70.5%). The overall average age was 78.5 years (range, 54-85 years). Results: The average follow-up was 6.5 months (range, 2-12). The achieved range of motion (ROM) was 110° of flexion (range, 70°-130°) and 5° of extension (range, 0°-20°). The average Knee Society Score (KSS) improved from 38 in the preoperative period to 82 in the postoperative period. Radiolucent lines (>2 mm) around the femoral or tibial components or around the stems were observed in 8 patients (23%). Five out of 34 patients (14.7%) developed complications. Three patients (8.9%) developed a deep infection. Two patients (5.9%) developed patellofemoral complications. Prosthesis survivorship without revision was 94% at 6.5 years. And, considering aseptic loosening as a revision cause, prosthesis survivorship was 100%. Conclusion: Modern rotatinghinge knee prostheses provide good outcomes in terms of function and pain relief. They also provide a low rate of aseptic loosening at mid-term follow-up. However, deep infection and septic loosening are common. Level of Evidence: IVObjetivo: Comunicar los resultados clínicos y radiológicos a mediano plazo de 34 artroplastias totales de rodilla abisagradas rotatorias. Materiales y Métodos: Se evaluó a un grupo de 34 prótesis abisagradas de rodilla. Se indicó una bisagra a 10 pacientes (29,5%) sometidos a una cirugía primaria y a 24 (70,5%), a una cirugía de revisión. La edad promedio de la serie era de 78.5 años (rango 54-85). Resultados: El seguimiento promedio fue de 6.5 años (rango 2-12). El rango de movilidad conseguido fue 110° de flexión (rango 70-130°) y 5° de extensión (rango 0-20°). El puntaje promedio en el KSS mejoró de 38 antes de la cirugía a 82 en el posoperatorio. En la evaluación radiológica, se detectaron líneas radiolúcidas >2 mm alrededor del componente femoral o tibial, o alrededor de los vástagos, en 8 casos (23%). Cinco de 34 pacientes (14,7%) sufrieron complicaciones. En tres casos (8,9%), se trató de una infección profunda. Dos pacientes (5,9%) tuvieron complicaciones rotulofemorales. La supervivencia de la prótesis libre de revisión a los 6.5 años fue del 94%. Si consideramos el aflojamiento aséptico como causa de revisión, la supervivencia fue del 100%. Conclusiones: Las prótesis abisagradas rotatorias de rodilla modernas logran buenos resultados funcionales y de alivio del dolor. También se asocian a bajas tasas de aflojamiento aséptico a mediano plazo. Sin embargo, las complicaciones sépticas son frecuente Nivel de Evidencia: I

TiNb2O7 and VNB9O25 of ReO3 type in hybrid Mg−Li batteries: Electrochemical and interfacial insights

As one of the beyond-lithium battery concepts, hybrid metal-ion batteries have aroused growing interest. Here, TiNb2O7 (TNO) and VNb9O25 (VNO) materials were prepared using a high-temperature solid-state synthesis and, for the first time, comprehensively examined in hybrid Mg−Li batteries. Both materials adopt ReO3-related structures differing in the interconnection of oxygen polyhedra and the resulting guest ion diffusion paths. We show applicability of the compounds in hybrid cells providing capacities comparable to those reached in Li-ion batteries (LIBs) at room temperature (220 mAh g−1 for TNO and 150 mAh g−1 for VNO, both at 0.1 C), their operability in the temperature range between −10 and 60 °C, and even better capacity retention than in pure LIBs, rendering this hybrid technology superior for long-term application. Post mortem X-ray photoelectron spectroscopy reveals a cathode−electrolyte interface as a key ingredient for providing excellent electrochemical stability of the hybrid battery. A significant contribution of the intercalation pseudocapacitance to charge storage was observed for both materials in Li- and Mg−Li batteries. However, the pseudocapacitive part is higher for TNO than for VNO, which correlates with structural distinctions, providing better accessibility of diffusion pathways for guest cations in TNO and, as a consequence, a higher ionic transport within the crystal structure. © 2020 American Chemical Societ

In-Depth Study of Li4Ti5O12Li_{4}Ti_{5}O_{12} Performing beyond Conventional Operating Conditions

Lithium-ion batteries (LIBs) are nowadays widely used in many energy storage devices, which have certain requirements on size, weight, and performance. State-of-the-art LIBs operate very reliably and with good performance under restricted and controlled conditions but lack in efficiency and safety when these conditions are exceeded. In this work, the influence of outranging conditions in terms of charging rate and operating temperature on electrochemical characteristics was studied on the example of lithium titanate (Li$_4$Ti$_5$O$_{12}$, LTO) electrodes. Structural processes in the electrode, cycled with ultrafast charge and discharge, were evaluated by operando synchrotron powder diffraction and ex situ X-ray absorption spectroscopy. On the basis of the Rietveld refinement, it was shown that the electrochemical storage mechanism is based on the Li-intercalation process at least up to current rates of 5C, meaning full battery charge within 12 min. For applications at temperatures between −30 and 60 °C, four carbonate-based electrolyte systems with different additives were tested for cycling performance in half-cells with LTO and metallic lithium as electrodes. It was shown that the addition of 30 wt % [PYR$_{14}$][PF$_6$] to the conventional LP30 electrolyte, usually used in LIBs, significantly decreases its melting point, which enables the successful low-temperature application at least down to −30 °C, in contrast to LP30, which freezes below −10 °C, making battery operation impossible. Moreover, at elevated temperatures up to 60 °C, batteries with the LP30/[PYR$_{14}$][PF$_6$] electrolyte exhibit stable long-term cycling behavior very close to LP30. Our findings provide a guideline for the application of LTO in LIBs beyond conventional conditions and show how to overcome limitations by designing appropriate electrolytes

Voltage hysteresis loop as a fingerprint of slow kinetics Co2+^{2+}-to-Co3+^{3+} transition in layered Nax_xCox/2_{x/2} Ti1−x/2_{1−x/2}O2_2 cathodes for sodium batteries

Sodium transition metal oxides are one of the most promising cathode materials for future sodium ion batteries. Chemical flexibility of layered Na-oxides including cobalt enables its partial substitution by other redox-active or non-active metals, often leading to structural stabilization. Sharing the same structural positions with other transition metals in layered oxides, Co can be double- or triple-charged, and as Co$^{3+}$ can adopt a low-spin (LS), intermediate-spin (IS), high-spin (HS) state, or a combination of them. Using Ti$^{4+}$ in the structure together with Co$^{2+}$ results in a reduced number of phase transformations compared to Ti-free compositions. However, a large potential hysteresis of about 1.5–2.5 V between battery charge and discharge is observed, pointing a first-order cooperative phase transition. Based on several examples, we found that Na extraction from Na$_x$Co$_{x/2}$Ti$_{1−x/2}$O$_2$ materials with high-spin HS-Co$^{2+}$, crystallizing in the P2 or O3 structure, mostly results in valence and spin-state transition of Co, leading to the formation of a second phase with a low-spin LS-Co$^{3+}$, and a much smaller unit cell volume. We elucidated a kinetic origin of the potential hysteresis, which can be minimized by increasing temperature or reduction of the current density during battery cycling with P2- and O3-Na$_{0.67}$Co$_{0.33}$Ti$_{0.67}$O$_2$ materials. The slow kinetics of the structural phase transition, especially upon Na-insertion, hampers the application of classical methods of electrochemical thermodynamics, such as determining the entropic potential dE/dT. We showed that the entropic potential depends only on the Na-content in Na$_x$Co$_{0.33}$Ti$_{0.67}$O$_2$ during battery charge or discharge, what additionally confirms a kinetic nature of the potential hysteresis