Influence of Rhizobium and Mycorrhizae in the Production of Seedlings of Caesalpinia Spinosa L. Taya in San Pablo, Peru

This research study evaluated the symbiotic influence of Mycorrhizae in the production of propagating material of Caesalpinia Spinosa L. Taya, as well as the characterization of strains of mycorrhitic fungi in field, nursery, and laboratory work. No nodules were found as a product of nitrifying bacteria in the roots of plants Caesalpinea spinosa L., and ectomycorrhitic fungi were identified in the rhizosphere, such as Basidiomicetes and species of Rhizoctonia sp and Fusarium sp. From the evaluations, T4 exceeded all treatments, such as in height, neck diameter, number of leaves, root length, and the wet and dry weight of Taya seedling. In conclusion, we say that the Caesalpinia Spinosa L. Taya, despite of belonging to the legume family, does not present nodulation; but the presence of ectomycorrhitic fungi such as the basidiomicetes in the rhizosphere and high content of organic matter, positively influences the increase in the volume of seedling in the nursery, also reflected in the absorption of protein and phosphorus. Keywords: mycorrhizal association, seedlings, rhizobium. Resumen En el presente trabajo de investigación se evaluó la influencia simbiótica de micorrizas en la producción de plantones de Caesalpinea spinosa L. Taya, así como la caracterización de cepas de hongos micorríticos, realizándose el trabajo en campo, vivero, y laboratorio. No se encontró nódulos como producto de bacterias nitrificantes en las raíces de las plantas de Caesalpinea spinosa L., y se identificó hongos ectomicorríticos en la rizósfera, tales como Basidiomicetes y especies de Rhizoctonia sp y Fusarium sp. De las evaluaciones el T4, supera a todos los tratamientos como en altura, diámetro de cuello, número de hojas, longitud de raíz, peso húmedo y peso seco de plántula.Concluyendo finalmente, diremos que la Caesalpinea spinosa L. taya, a pesar de pertenecer a la familia de las Leguminosas no presenta nodulación; pero la presencia de los hongos ectomicorríticos como los basidiomicetes en la rizósfera y el alto contenido de materia orgánica, influye positivamente en el incremento del volumen de la plántula en vivero, reflejado también en la absorción de proteínas y fosforo. Palabras clave: asociación micorrítica, plantones, rizobium

Matter effects in neutrino visible decay at future long-baseline experiments

Neutrino visible decay in the presence of matter is re-evaluated. We study these effects in two future long-baseline experiments where matter effects are relevant: DUNE (1300 km) and a hypothetical beam aimed towards ANDES (7650 km). We find that matter effects are negligible for the visible component of neutrino decay at DUNE, being much more relevant at ANDES. We perform a detailed simulation of DUNE, considering $\nu_\mu$ disappearance and $\nu_e$ appearance channels, for both FHC and RHC modes. The sensitivity to the decay constant $\alpha_3$ can be as low as $2\times10^{-6}$ eV$^2$ at 90% C.L., depending on the neutrino masses and type of coupling. We also show the impact of neutrino decay in the determination of $\theta_{23}$ and $\delta_{\rm CP}$, and find that the best-fit value of $\theta_{23}$ can move from a true value at the lower octant towards the higher octant.Comment: 18 pages; v2: Minor changes, version accepted for publication in EPJ

Own-company stockholding and work effort preferences of an unconstrained executive

We develop a framework for analyzing an executive's own-company stockholding and work effort preferences. The executive, characterized by risk aversion and work effectiveness parameters, invests his personal wealth without constraint in the financial market, including the stock of his own company whose value he can directly influence with work effort. The executive's utility-maximizing personal investment and work effort strategy is derived in closed form, and a utility indifference rationale is applied to determine his required compensation. Being unconstrained byperformance contracting, the executive's work effort strategy establishes a base case for theoretical or empirical assessment of the benefits or otherwise of constraining executives with performance contracting

On Necessary and Sufficient Conditions for Near-Optimal Singular Stochastic Controls

This paper is concerned with necessary and sufficient conditions for near-optimal singular stochastic controls for systems driven by a nonlinear stochastic differential equations (SDEs in short). The proof of our result is based on Ekeland's variational principle and some delicate estimates of the state and adjoint processes. This result is a generalization of Zhou's stochastic maximum principle for near-optimality to singular control problem.Comment: 19 pages, submitted to journa

Trematodos del ganado vacuno lechero al pastoreo en Cajamarca, Perú: Fasciola hepatica y Calicophoron microbothrioides

The study determines the prevalence of trematodes through coproparasitology in grazing dairy cattle in six districts of the Cajamarca region. The analyzes and processing of the faecal samples were carried out by natural sedimentation. The proportion of parasitized animals was 50.4 ± 2.1% (1092/2169), only Fasciola hepatica 32.4 ± 2.0% (703/2169), Calicophoron microbothrioides 17.9 ± 1.6% (389/2169) and coinfection by both parasites was 7.51 ± 1.11% (163/2169). The prevalence by district in Cajamarca was 49.5±5.0% (188/380), Baños del Inca 61.2±5.6% (181/296), La Encañada 80.7±4.1% (284/352), Celendín 45.4±5.0% (171 /377), San Juan 50.0±5.0% (190/380) and Chota 20.3±4.0% (78/384). There was no statistical association in the presence of both trematodes in the animals (p>0.95), nor was a correlation found between the altitude of each district and the presence of faecal eggs (r=0.19). It is concluded that the prevalence of trematodes in extensively reared dairy cattle in Cajamarca is high, with the greatest presence of F. hepatica, followed by C. microbothrioides and their coexistence.El estudio determina la prevalencia de trematodos mediante coproparasitología en ganado vacuno lechero de crianza al pastoreo en seis distritos de la región Cajamarca. Los análisis y procesamiento de las muestras fecales se realizaron mediante sedimentación natural. La proporción de animales parasitados fue de 50.4±2.1% (1092/2169), de Fasciola hepatica de 32.4±2.0% (703/2169) y Calicophoron microbothrioides de 17.9±1.6% (389/2169), en tanto que la coinfección por ambos parásitos fue de 7.51±1.11% (163/2169). Las prevalencias por distrito fueron en Cajamarca de 49.5±5.0% (188/380), Baños del Inca 61.2±5.6% (181/296), La Encañada 80.7±4.1% (284/352), Celendín 45.4±5.0% (171/377), San Juan 50.0±5.0% (190/380) y Chota 20.3±4.0% (78/384). No hubo asociación estadística en la presentación de ambos trematodos en los animales (p>0.95), ni se encontró correlación entre la altitud de cada distrito y la presencia de huevos fecales (r=0.19). Se concluye que, la prevalencia de trematodos en ganado vacuno lechero de crianza extensiva en Cajamarca es alta, con mayor presencia de F. hepatica, seguido de C. microbothrioides y su coexistencia