Associahedra via spines

An associahedron is a polytope whose vertices correspond to triangulations of a convex polygon and whose edges correspond to flips between them. Using labeled polygons, C. Hohlweg and C. Lange constructed various realizations of the associahedron with relevant properties related to the symmetric group and the classical permutahedron. We introduce the spine of a triangulation as its dual tree together with a labeling and an orientation. This notion extends the classical understanding of the associahedron via binary trees, introduces a new perspective on C. Hohlweg and C. Lange's construction closer to J.-L. Loday's original approach, and sheds light upon the combinatorial and geometric properties of the resulting realizations of the associahedron. It also leads to noteworthy proofs which shorten and simplify previous approaches.Comment: 27 pages, 11 figures. Version 5: minor correction

Performance of Dairy Goats to Alfalfa Silage Based Diets Supplemented with Different Sources of Carbohydrates

Lactating Saanen dairy goats fed alfalfa silage (AS) based diets in four 4x4 Latin Square designed experiment were studied for the effects of supplementation of three different type of carbohydrates (wheat grain, (W); sorghum grain, (SG) and dry citrus pulp, (DCP)) on milk yield, composition and chewing activities. Sixteen does (45± 10 DIM and 2.016 kg ± 0.48 4% FCM) housed indoors in individual pens in a four 4x4 experiment were fed four diets 1) AS (33.9%DM, 19.9%CP, 44.01%NDF); 2) ASW (52.4%DM, 19.8%CP, 33.7%NDF); 3) ASSG (50.9%DM, 17.9%CP, 37%NDF), 4) ASDCP (52.5%DM, 16.12%CP, 39.1%NDF) with forage-to-concentrate ratios of 100:0 or 65:35, 67:33 and 64:36 respectively. Intake of AS DM (2.78%BW) was different (P\u3c 0.05) from the other treatments (average 3.53 ±0.07 %BW). Chewing efficiency (min/g NDF per kg BW 0.75) decrease (P\u3c 0.05) as a result of AS substitution or concentrate supplementation without effect (P\u3e 0.05) of carbohydrate type or dietary level of NDF. Milk, 4%FCM and fat-protein-corrected milk yield was affected (P\u3c 0.05) by concentrate supplementation. Either milk protein content (g/l) or yield (g/day) were not affected by treatments. Body weight changes appeared related to concentrate supplementation. Supplementation increase total DM intake, decrease forage DM intake and chewing efficiency and increase producing performance without changing milk composition

Homology Modeling of Leishmanolysin (gp63) from Leishmania panamensis and Molecular Docking of Flavonoids

Leishmaniasis is a chronic disease caused by protozoa of the distinct Leishmania genus transmitted by sandflies of the genus Phlebotomus (old world) and Lutzomyia (new world). Among the molecular factors that contribute to the virulence and pathogenesis of Leishmania are metalloproteases, e.g., glycoprotein 63 (gp63), also known as leishmanolysin or major surface protease (MSP). This protease is a zinc-dependent metalloprotease that is found on the surface of the parasite, abundant in Leishmania promastigote and amastigote. This study describes the prediction of three-dimensional (3D) structures of leishmanolysin (UniProt ID A0A088RJX7) of Leishmania panamensis employing a homology modeling approach. The 3D structure prediction was performed using the SWISS-MODEL web server. The tools PROCHECK, Molprobyty, and Verify3D were used to check the quality of the model, indicating that they are reliable. Best docking configurations were identified applying AutoDock Vina in PyRx 0.8 to obtain a potential antileishmanial activity. Biflavonoids such as lanaroflavone, podocarpusflavone A, amentoflavone, and podocarpusflavone B showed good scores among these molecules. Lanaroflavone appears to be the most suitable compound from binding affinity calculations

Lecciones aprendidas al enfrentar los efectos de eventos hidrometeorológicos extremos en los sistemas agrícolas y servicios ecosistémicos en América Latina.

Se realizó una exploración inicial sobremedidas de adaptación implementadas frente a Eventos Hidrometeorológicos Extremos (EHE) en zonas rurales, extraídas de sitios seleccionados en Argentina, Brasil, Chile, Colombia y Ecuador; el primer desafío encontrado fue la definición de EHE; puesto que la misma cambia si se la enfoca desde el punto de vistameteorológico o hidrológico; además, no existe acuerdo en la definición de valores límites para caracterizar estos eventos dentro de la región; finalmente, en muchos de los sitios donde se realizó este estudio no existen registros lo suficientemente largos y confiables para poder cuantificar los EHE; en consecuencia se decidió utilizar una definición "empírica" de EHE, dejando que sean los actores sociales que vivieron la experiencia los que determinen cuando ocurrió un evento de esa naturaleza. A pesar de las diferencias en la vulnerabilidad y los impactos sobre los paisajes rurales de cada sitio, las evidencias sugieren que la gestión integrada de los paisajes a nivel comunitario permite a los productores agrícolas adoptar medidas de adaptación a su debido tiempo y preparar a las comunidades rurales para enfrentarse y responder ante la ocurrencia de EHE. Entre las lecciones aprendidas más importantes se identificaron: La demanda de una adecuada transferencia de información relacionada a EHE; la necesidad de promoción del capital social; la importancia de tener un Estado desempeñando un rol proactivo; la relevancia de tener una prensa que oriente y no escandalice; y la necesidad de contar con mecanismos óptimos para estimación de costos

Lecciones aprendidas al enfrentar los efectos de eventos hidrometeorológicos extremos en los sistemas agrícolas y Servicios ecosistémicos en América Latina

En este trabajo realizamos una exploración inicial sobre medidas de adaptación implementadas en nuestra región frente a Eventos Hidrometeorológicos Extremos (EHE) en zonas rurales, identificando tanto experiencias positivas como negativas.  Estas medidas son extraídas de estudios de casos realizados en sitios seleccionados en Argentina, Brasil, Chile, Colombia y Ecuador; describiendo las experiencias de diferentes actores y organizaciones sociales. Se utilizaron tanto fuentes primarias (expertos, involucrados/afectados) como secundarias (bases de datos, artículos científicos, publicaciones oficiales, notas de prensa, etc.). El primer desafío encontrado fue la definición de EHE;  en primer lugar, puesto que la misma cambia si se la enfoca desde el punto de vista meteorológico o hidrológico; en segundo lugar no existe acuerdo en la definición de valores límites para caracterizar estos eventos dentro de la región, dadas sus características socio-ambientales; y en tercer lugar en muchos de los sitios donde se realizó este estudio no existen registros lo suficientemente largos y confiables para poder cuantificar los EHE. En vista de lo anterior decidimos utilizar una definición “empírica” de EHE, dejando que sean los actores sociales que vivieron la experiencia los que determinen cuando ocurrió un evento de esa naturaleza. A pesar de las diferencias en la vulnerabilidad y los impactos sobre los paisajes rurales que se encuentran en cada estudio de caso, esta investigación sugiere que la gestión integrada de los paisajes a nivel comunitario  permite  a los productores agrícolas adoptar medidas de adaptación a su debido tiempo y preparar a las comunidades rurales para enfrentarse y responder ante la ocurrencia de EHE.   Esto ilustra la importancia de mantener paisajes multifuncionales, donde los agroecosistemas se combinan con ecosistemas para amortiguar el impacto negativo de los EHE, principalmente a través de procesos de regulación hídrica. Finalmente entre las lecciones aprendidas más importantes se identificaron las siguientes: La demanda de una adecuada transferencia de la información; la necesidad de promoción del capital social; la importancia de tener un Estado desempeñando un rol proactivo; la relevancia de tener una prensa que oriente y no escandalice; y la necesidad de contar con mecanismos óptimos para estimación de costos

Breeding cassava for enhancement of carotenoid in the biofortification program in Brazil.

This work aimed towards the improvement of the nutritional quality of cassava varieties regarding carotenoid, Fe and Zn contents, inside the HarvestPlus program scenario. Initially, a total of 1800 cassava accessions, from the germplasm bank at Embrapa Cassava & Tropical Fruits, were screened. Total carotenoid contents in one-year old roots of the 72 landraces selected ranged from 0.63 to 15.51 ìg.g-1 (fresh weight). However, it was detected that the accessions with higher carotenoid contents also presented elevated HCN levels. Thus, based on the low cyanogenic potential required for the consumption of boiled cassava roots (where carotenoid retention is higher), 7 landraces with carotenoid concentrations ranging from 1.50 to 4.49 ìg.g-1 were selected as parents. In the first generation (228 genotypes), hybrids with a carotenoid increment of more than 100% in relation to the parents were identified. Carotenoid levels in the population ranged from 0.87 to 10.47 ìg.g-1. Analyses of beta-carotenes revealed an approximated, but not linear, relation with the total carotenoid contents. In the second generation (136 hybrids), additional increment of carotenoid contents in relation to the first was verified, reaching the maxim concentration of 12.41 ìg.g-1. Regarding Fe and Zn contents, the 72 yellow landraces initially selected, as well as all the hybrids of the two generations, were evaluated by atomic absorption. Keeping low HCN and high carotenoid concentrations as priority, hybrids with more than 10 ìg.g-1 of carotenoids and with high levels of Zn and Fe were selected. These hybrids are currently under agronomical evaluations to be recommended as varieties.TH25

Radio Loud and Radio Quiet Active Galactic Nuclei

We generated a sample of 409 AGNs for which both the radio luminosity at 5 GHz and the line luminosity in [OIII] 5007 have been measured. The radio luminosity spans a range of ten orders of magnitude, and the [OIII] line luminosity spans a range of eight orders of magnitude --- both considerably larger than the ranges in previous studies. We show that these two quantities are correlated in a similar way for both radio-loud and radio-quiet AGNs. We demonstrate that the observed correlation can be explained in terms of a model in which jets are accelerated and collimated by a vertical magnetic field.Comment: 45 pages inc. 7 figures, 1 table of 15 pages in ps-format. Accept to AJ September 199

The Far-Infrared Spectral Energy Distributions of X-ray-selected Active Galaxies

[Abridged] We present ISO far-infrared (IR) observations of 21 hard X-ray selected AGN from the HEAO-1 A2 sample. We compare the far-IR to X-ray spectral energy distributions (SEDs) of this sample with various radio and optically selected AGN samples. The hard-X-ray selected sample shows a wider range of optical/UV shapes extending to redder near-IR colors. The bluer objects are Seyfert 1s, while the redder AGN are mostly intermediate or type 2 Seyferts. This is consistent with a modified unification model in which the amount of obscuring material increases with viewing angle and may be clumpy. Such a scenario, already suggested by differing optical/near-IR spectroscopic and X-ray AGN classifications, allows for different amounts of obscuration of the continuum emission in different wavebands and of the broad emission line region which results in a mixture of behaviors for AGN with similar optical emission line classifications. The resulting limits on the column density of obscuring material through which we are viewing the redder AGN are 100 times lower than for the standard optically thick torus models. The resulting decrease in optical depth of the obscuring material allows the AGN to heat more dust at larger radial distances. We show that an AGN-heated, flared, dusty disk with mass 10^9 solar and size of few hundred pc is able to generate optical-far-IR SEDs which reproduce the wide range of SEDs present in our sample with no need for an additional starburst component to generate the long-wavelength, cooler part of the IR continuum.Comment: 40 pages, 14 figures, accepted for publication in Astrophysical Journal, V. 590, June 10, 200