Sowing the wheat seeds of Afghanistan's future

Nigel Poole Rajiv Sharma Orzala Nemat Jason Donovan Alison Bentley (2022, [Artículo])

Humanitarian Intervention CIENCIAS AGROPECUARIAS Y BIOTECNOLOGÍA FOOD SECURITY IRRIGATION NUTRITION PLANT BREEDING SEED SYSTEMS

Análisis isotópico en plumas del Charrán mínimo (Sternula antillarum) para inferir su ecología trófica

Isotope analysis in feathers of the Least Tern (Sternula antillarum) to infer its trophic ecology

Andehui Danay Morales Flores (2024, [Tesis de maestría])

El análisis isotópico de plumas primarias utilizando las razones isotópicas δ13C y δ15N permitió estimar la amplitud y superposición del nicho trófico de los conjuntos de las colonias reproductivas de adultos y volantones del charrán mínimo. Se infirió la amplitud del nicho por medio del área de la elipse estándar estimada por métodos Bayesianos (SEAB), se encontró que existen diferencias entre el nicho trófico de adultos y volantones, pues los adultos tienen valores de la media SEAB de 16.3‰2 hasta 28.4‰2 y los volantones de 44.8‰2 hasta 75.5‰2, esto podría ser debido a diferencias en cuanto a las presas seleccionadas y la ubicación geográfica de los adultos durante la muda de las primarias. Por otro lado, la superposición del nicho indicó la similitud entre los adultos de diferentes colonias, por lo cual, se consideró que los adultos de algunas colonias podrían compartir un sitio de invernada o bien la temporalidad en la muda de las primarias. Además, se cumplió con el objetivo de caracterizar la variabilidad de las firmas isotópicas de carbono y nitrógeno durante el crecimiento secuencial de las plumas primarias por medio de los modelos aditivos generalizados y se observó la variabilidad entre las primarias utilizando las anomalías respecto a la media local de cada colonia, lo cual permitió diferenciar estrategias de alimentación específicas para ciertos conjuntos y la variabilidad en la dieta. La búsqueda bibliográfica de los sitios potenciales de migración en invierno más los mapas de gradientes isotópicos de δ13C permitió determinar que el Océano Pacífico Oriental Tropical es la región geográfica relacionada con la distribución δ13C en plumas primarias del charrán mínimo y es el sitio más probable de invernada.

The isotopic analysis of primary feathers using the isotopic ratios of δ13C and δ15N allowed the estimation of the breadth and overlap of the trophic niche of adult and fledgling least terns. Niche breadth was inferred through the standard ellipse area (SEAB) estimated by Bayesian methods. We found differences between the trophic niche of adults and fledglings, as adults presented mean SEAB values from 16.3‰2 to 28.4‰2 and fledglings from 44.8‰2 to 75.5‰2. This could be due to differences in the prey selected and the geographical location of the adults during the molt of the primaries. The overlap of these values among adults indicates similarity in prey selection and location between the adults of different colonies. Therefore, it was considered that the adults of some colonies could share a wintering site during the period of molt of the primary feathers. We characterized the variability of carbon and nitrogen isotopic signatures during the sequential growth of primary feathers through generalized additive models and the variability between primaries using the anomalies of these signatures and the local mean for each colony. This allowed us to differentiate specific feeding strategies of individual least terns and the variability in their diet. The bibliographic search for potential migration and wintering sites found published maps of δ13C isotopic gradients in the Tropical Eastern Pacific Ocean that correspond to the δ13C distribution in primary feathers of the least tern, indicating a potential wintering area for this species.

isótopos, carbono, nitrógeno, ave marina, ecología trófica isotopes, seabird, nitrogen, carbon, trophic ecology BIOLOGÍA Y QUÍMICA CIENCIAS DE LA VIDA BIOLOGÍA VEGETAL (BOTÁNICA) ECOLOGÍA VEGETAL ECOLOGÍA VEGETAL

Effect of Nitrogen, Phosphorus and Potassium on regional organic substrates in Agave salmiana production in Huichapan, Hidalgo, Mexico

EMILIO RAYMUNDO MORALES MALDONADO MONICA GUTIERREZ ROJAS RAMON JAIME HOLGUIN PEÑA Daniel Ruiz-Juárez Jorge Luis Vega Chávez Ana Cristina Reyes Godoy (2022, [Artículo])

"Mexico has 159 species of Agave spp. In the agri-food industry stand out are Agave tequilana, A. angustifolia, and A. salmiana. A limitation to producing maguey seedlings is the low availability of organic substrates that favor plant adaptation in the field. The objective was to evaluate the effect of nitrogen (N), phosphorus (P) and potassium (K) found in substrates in response to vegetative and root growth of A. salmiana in agricultural areas of Huichapan, Hidalgo, Mexico. The treatment consisted of earthworm humus (EH) and leaf compost (LC) substrates with materials from the region with different percentages of EH (100, 75, 50%), LC (5, 10%), and sand (20, 40%). The treatments were applied with 14 random replications in two phases in seeds and 40-day-seedlings. The variables evaluated were NPK amount and pH in substrates. The physiological variables measured were plant height, leaf number, stem diameter, root length, and volume. Significant differences (P≤0.05) were observed in seedling physiology due to the effect of the treatment. The best agronomic responses (plant growth and root length/weight) of Agave seedlings were T5 (75% earthworm humus + 20% sand + 5% leaf-soil) and T6 (50% earthworm humus + 40% sand + 10% leaf-soil); in both treatments, the NPK percentages were different from the control (Haplic Phaeozem soil) group. The final concentration of NPK in T6 was N = 0.04%, P = 398.13 mg Kg-1 and K = 11.88 meq 100g-1 . The results infer that NPK availability in soil and progressive acidification (initial pH = 8.6, final pH = 7.4) of the substrate can favorably influence the plant response. The interactions between NPK availability in the substrate and their use for a better response in maguey seedling adaptability open up new lines of research on the productive systems in the región of Huichapan, Hidalgo, Mexico."

maguey, nutritional quality, plant physiology, productive soils, seedling BIOLOGÍA Y QUÍMICA CIENCIAS DE LA VIDA BIOLOGÍA VEGETAL (BOTÁNICA) FERTILIDAD DEL SUELO FERTILIDAD DEL SUELO

Vibrissa growth rate in California sea lions based on environmental and isotopic oscillations

MARTHA PATRICIA ROSAS HERNANDEZ (2018, [Artículo])

Pinniped vibrissae provide information on changes in diet at seasonal and annual scales; however, species-specific growth patterns must first be determined in order to interpret these data. In this study, a simple linear model was used to estimate the growth rate of vibrissae from adult female California sea lions (Zalophus californianus) from San Esteban Island in the Gulf of California, Mexico. The δ15N and δ13C values do not display a marked oscillatory pattern that would permit direct determination of the time period contained in each vibrissa; thus, time (age) was calculated in two ways: 1) based on the correlation between the observed number of peaks (Fourier series) in the δ15N profile and the length of each vibrissa, and 2) through direct comparison with the observed number of peaks in the δ15N profile. Cross-correlation confirmed that the two peaks in the δ15N profile reflected the two peaks in the chlorophyll-a concentration recorded annually around the island. The mean growth rate obtained from the correlation was 0.08 ± 0.01 mm d-1, while that calculated based on the observed number of peaks was 0.10 ± 0.05 mm d-1. Both are consistent with the rates reported for adult females of other otariid species (0.07 to 0.11 mm d-1). Vibrissa growth rates vary by individual, age, sex, and species; moreover, small differences in the growth rate can result in significant differences over the time periods represented by the isotopic signal. Thus, it is important to assess this parameter on a species-by-species basis. © 2018 Rosas-Hernández et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

carbon, nitrogen, animal, California, chemistry, diet, female, island (geological), Mexico, Otariidae, physiology, Animals, California, Carbon Isotopes, Diet, Female, Islands, Mexico, Nitrogen Isotopes, Sea Lions CIENCIAS FÍSICO MATEMÁTICAS Y CIENCIAS DE LA TIERRA CIENCIAS DE LA TIERRA Y DEL ESPACIO OCEANOGRAFÍA OCEANOGRAFÍA

Vibrissa growth rate in California sea lions based on environmental and isotopic oscillations

MARTHA PATRICIA ROSAS HERNANDEZ (2018, [Artículo])

Pinniped vibrissae provide information on changes in diet at seasonal and annual scales; however, species-specific growth patterns must first be determined in order to interpret these data. In this study, a simple linear model was used to estimate the growth rate of vibrissae from adult female California sea lions (Zalophus californianus) from San Esteban Island in the Gulf of California, Mexico. The δ15N and δ13C values do not display a marked oscillatory pattern that would permit direct determination of the time period contained in each vibrissa; thus, time (age) was calculated in two ways: 1) based on the correlation between the observed number of peaks (Fourier series) in the δ15N profile and the length of each vibrissa, and 2) through direct comparison with the observed number of peaks in the δ15N profile. Cross-correlation confirmed that the two peaks in the δ15N profile reflected the two peaks in the chlorophyll-a concentration recorded annually around the island. The mean growth rate obtained from the correlation was 0.08 ± 0.01 mm d-1, while that calculated based on the observed number of peaks was 0.10 ± 0.05 mm d-1. Both are consistent with the rates reported for adult females of other otariid species (0.07 to 0.11 mm d-1). Vibrissa growth rates vary by individual, age, sex, and species; moreover, small differences in the growth rate can result in significant differences over the time periods represented by the isotopic signal. Thus, it is important to assess this parameter on a species-by-species basis. © 2018 Rosas-Hernández et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

carbon, nitrogen, animal, California, chemistry, diet, female, island (geological), Mexico, Otariidae, physiology, Animals, California, Carbon Isotopes, Diet, Female, Islands, Mexico, Nitrogen Isotopes, Sea Lions BIOLOGÍA Y QUÍMICA CIENCIAS DE LA VIDA INMUNOLOGÍA INMUNOLOGÍA

Usando la descomposición de un grafo Halin para el diseño de algoritmos autoestabilizantes

Using Halin graph decomposition for the design of self-stabilizing algorithm

Daniel Uriel Orozco Lomelí (2023, [Tesis de maestría])

Sea G = (V, E) un grafo no dirigido. El problema de encontrar un conjunto independiente fuerte en G, es identificar un conjunto S ⊆ V , tal que dados dos vértices arbitrarios de S, éstos estén separados entre sí por el menos tres aristas. Encontrar un conjunto S de tamaño máximo pertenece a la clase NP-Difícil. Por otro lado, el problema de encontrar un conjunto dominante total en G es identificar un conjunto D ⊆ V , tal que cualquier vértice en V tenga al menos un vecino que pertenezca a D. Encontrar un conjunto D de tamaño mínimo también pertenece a la clase NP-Difícil. En este trabajo de tesis se diseñaron dos algoritmos, uno que resuelve el problema de encontrar un conjunto independiente fuerte maximal y otro que resuelve el problema de encontrar un conjunto dominante total minimal. Estos dos problemas son menos restrictivos que las versiones de optimización descritas al principio de este texto y se sabe que pertenecen a la clase P. Los algoritmos diseñados corren en un sistema distribuido, son autoestabilizantes, son tolerantes a fallas transitorias y funcionan para grafos Halin. Los grafos Halin pertenecen a la clase de grafos 2-outerplanares y tienen la propiedad de que se pueden partir en dos subgrafos muy conocidos, un árbol y un ciclo. Los algoritmos propuestos aprovechan la propiedad anterior para disminuir la complejidad de los mismos. Hasta donde tenemos conocimiento, los algoritmos propuestos, que corren en tiempo lineal en el número de vértices, son los algoritmos más rápidos existentes para los problemas del conjunto independiente fuerte maximal y el conjunto dominante total minimal.

Let G = (V, E) be an undirected graph. The problem of finding a strong stable set in G, is to identify a set S ⊆ V , such that given two arbitrary vertices of S, they are separated from each other by at least three edges. Finding a set S of maximum size belongs to the class NP-Hard. On the other hand, the problem of finding a total dominanting set in G is to identify a set D ⊆ V , such that any vertex in V has at least one neighbor belonging to D. Finding a set D of minimum size also belongs to the class NP-Hard. In this thesis work, two algorithms were designed, one that solves the problem of finding a maximal strong stable set and one that solves the problem of finding a minimal total dominanting set. These two problems are less restrictive than the optimization versions described at the beginning of this text and are known to belong to the P class. The designed algorithms run on a distributed system, are self-stabilizing, are transient fault tolerant, and work for Halin graphs. Halin graphs belong to the 2-outerplanar class of graphs and have the property that they can be split into two well-known subgraphs, a tree and a cycle. The proposed algorithms take advantage of the above property to decrease the complexity of the algorithms. To the best of our knowledge, the proposed algorithms, which run in linear time in the number of vertices, are the fastest existing algorithms for the maximal strong stable set and minimal total dominating set problems.

Grafo Halin, Sistemas Distribuidos, Autoestabilización, Conjunto Independiente Fuerte, Conjunto Dominante Total Halin Graph, Distributed Systems, Self-stabilizing, Strong Stable Set, Total Dominating Set INGENIERÍA Y TECNOLOGÍA CIENCIAS TECNOLÓGICAS TECNOLOGÍA DE LOS ORDENADORES LENGUAJES ALGORÍTMICOS LENGUAJES ALGORÍTMICOS