The application of a mechanistic model to analyze the factors that affect the lactation curve parameters of dairy sheep in Mexico

Pollott́s mechanistic model has been designed to describe lactation curve parameters based on the known biology of milk production and can be useful for analyzing the factors that affect this process. A total of 553 lactations (9956 weekly test-day records) of crossbred dairy sheep from four commercial farms located in Mexico, were analyzed to investigate environmental factors that influenced lactation curve parameters, using Pollott’s 5-parameter additive model. This model was fitted to each lactation using an iterative nonlinear procedure. The estimated parameters were maximum milk secretion potential (MSmax), relative rate of increase in cell differentiation (GR), maximum secretion loss (MSLmax), relative rate of decline in cell numbers (DR) and the proportion of parenchyma cells dead at parturition. A general linear model procedure was used to determine the effect of type of lambing, lambing number, flock and lambing season on total lactation milk yield (TMY), lactation length and estimated parameters of the Pollott model. Ewes had an average milk yield of 74.4 L with an average lactation length of 140 days. Flock had a significant (P < 0.05) effect on most of the analyzed traits, which can be explained by the different farmś management practices. The TMY were significantly (P = 0.005) higher for twin-lambing than single-lambing lactations. Sheep in their first lambing had lower TMY than those in their fourth lambing (P = 0.01), possibly explained by the lower values of MSmax (2.85 vs. 5.3 L) and the decrease in DR throughout life (P = 0.03). However, the relative GR was greatest (P = 0.04) during first lambing and then decreased as lambing number increased. Both lambing number and type of lambing also affected milk yield. The parameters of the Pollott model can be useful to explain, with a biological approximation, the dynamics of differentiation, secretion and death of mammary cells in dairy sheep

Cosecheros-huerteros: bajo la sombra de los monopolios cacaoteros del Guayaquil colonial

The purpose of this writing is to admit the participation of the cosecheros-huerteros in the internal processes of the networks that they controlled the agro-exporting and mercantile trade in the colonial Guayaquil. On sources of the Historical Archive of Guayas unravel negotiations, contracts and disputes. In synthesis, the article reveals a range of strategies and interests own; disagreements and vicissitudes of those involved in the productive and operative chain of the traffic of the cocoa.El propósito de este escrito es reconocer la participación de los cosecheros-huerteros en los procesos internos de las redes que controlaron el comercio agro-exportador y mercantil en el Guayaquil colonial. Sobre fuentes notariales del Archivo Histórico del Guayas se desentrañan negociaciones, contratos y querellas. En síntesis, el artículo deja al descubierto una gama de estrategias e intereses, desavenencias y vicisitudes propias de quienes intervinieron en la cadena productiva y operativa del tráfico del cacao

A superconducting transformer system for high current cable testing

This article describes the development of a direct-current (dc) superconducting transformer system for the high current test of superconducting cables. The transformer consists of a core-free 10 464 turn primary solenoid which is enclosed by a 6.5 turn secondary. The transformer is designed to deliver a 50 kA dc secondary current at a dc primary current of about 50 A. The secondary current is measured inductively using two toroidal-wound Rogowski coils. The Rogowski coil signal is digitally integrated, resulting in a voltage signal that is proportional to the secondary current. This voltage signal is used to control the secondary current using a feedback loop which automatically compensates for resistive losses in the splices to the superconducting cable samples that are connected to the secondary. The system has been commissioned up to 28 kA secondary current. The reproducibility in the secondary current measurement is better than 0.05% for the relevant current range up to 25 kA. The drift in the secondary current, which results from drift in the digital integrator, is estimated to be below 0.5 A/min. The system's performance is further demonstrated through a voltage-current measurement on a superconducting cable sample at 11 T background magnetic field. The superconducting transformer system enables fast, high resolution, economic, and safe tests of the critical current of superconducting cable samples

Prioritizing investments for climate-smart agriculture: Lessons learned from Mali

Agricultural productivity and growth in Mali are under threat from erratic rainfall, resulting in more frequent dry years. The national economy is vulnerable to climate change due to 50% of the gross domestic product coming from the agricultural sector and 75% of the population living in rural areas. The Climate-Smart Agriculture (CSA) concept arises from a need to provide innovative solutions towards the complex and integrated goals of increasing yields, improving resilience, and promoting a low emissions agricultural sector. A major challenge for policymakers to operationalize CSA is the identification, valuation (cost-benefit), and subsequent prioritization of climate-smart options and portfolios (groups of CSA options) for investment. This paper presents the process, results, and lessons learned from a yearlong pilot of the Climate-Smart Agriculture Prioritization Framework (CSA-PF) in Mali. Key national and international stakeholders participated in the co-development and prioritization of two CSA portfolios and related action plans for the Malian Sudanese zone. Initial steps towards outcomes of the process include inclusion of prioritized CSA practices in ongoing development projects and prompting discussion of modifications of future calls for agricultural development proposals by regional donors

Improving Latin American soil information database for digital soil mapping enhances its usability and scalability

Spatial soil databases can help model complex phenomena in which soils are decisive, for example, evaluating agricultural potential or estimating carbon storage capacity. The Soil Information System for Latin America and the Caribbean, SISLAC, is a regional initiative promoted by the FAO's South American Soil Partnership to contribute to the sustainable management of soil. SISLAC includes data coming from 49,084 soil profiles distributed unevenly across the continent, making it the region's largest soil database. However, some problems hinder its usages, such as the quality of the data and its high dimensionality. The objective of this research is twofold. First, to evaluate the quality of SISLAC and its data values and generate a new, improved version that meets the minimum quality requirements to be used by different interests or practical applications. Second, to demonstrate the potential of improved soil profile databases to generate more accurate information on soil properties, by conducting a case study to estimate the spatial variability of the percentage of soil organic carbon using 192 profiles in a 1473 km2 region located in the department of Valle del Cauca, Colombia. The findings show that 15 percent of the existing soil profiles had an inaccurate description of the diagnostic horizons. Further correction of an 4.5 additional percent of existing inconsistencies improved overall data quality. The improved database consists of 41,691 profiles and is available for public use at ttps://doi.org/10.5281/zenodo.6540710 (Díaz-Guadarrama, S. & Guevara, M., 2022). The updated profiles were segmented using algorithms for quantitative pedology to estimate the spatial variability. We generated segments one centimeter thick along with each soil profile data, then the values of these segments were adjusted using a spline-type function to enhance vertical continuity and reliability. Vertical variability was estimated up to 150 cm in-depth, while ordinary kriging predicts horizontal variability at three depth intervals, 0 to 5, 5 to 15, and 15 to 30 cm, at 250 m-spatial resolution, following the standards of the GlobalSoilMap project. Finally, the leave-one-out cross validation provides information for evaluating the kriging model performance, obtaining values for the RMSE index between 1.77% and 1.79% and the R2 index greater than 0.5. The results show the usability of SISLAC database to generate spatial information on soil properties and suggest further efforts to collect a more significant amount of data to guide sustainable soil management.Fil: Diaz Guadamarra, Sergio. Universidad Nacional de Colombia. Facultad de Ciencias Agrarias. Departamento de Agronomía; ColombiaFil: Lizarazo, Iván. Universidad Nacional de Colombia. Facultad de Ciencias Agrarias. Departamento de Agronomía; ColombiaFil: Guevara, Mario. Universidad Nacional Autónoma de México. Campus Juriquilla. Centro de Geociencias; MéxicoFil: Guevara, Mario. Universidad Nacional Autónoma de México.Campus Juriquilla. Centro de Geociencias; México. United States Department of Agriculture. Soil Salinity National Laboratory, Estados UnidosFil: Angelini, Marcos Esteban. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Suelos; Argentina. Wageningen University. Soil Geography and Landscape Group; Países Bajos. International Soil Reference and Information Centre. World Soil Information; Países BajosFil: Araujo Carrillo, Gustavo A. Corporación Colombiana de Investigación Agropecuaria AGROSAVIA; ColombiaFil: Argeñal, Jainer. Universidad Nacional Autónoma de Honduras. Facultad de Ciencias; Honduras.Fil: Armas, Daphne. Universidad de Almería. Departamento de Agronomía, Edif. CITEIIB, España.Fil: Balsa, Rafael A. Ministerio de Desarrollo Agrario y Riego. Dirección General de Asuntos Ambientales Agrarios, Perú.Fil: Bolivar, Adriana. Instituto Geográfico Agustín Codazzi. Subdirección Agrología; ColombiaFil: Bustamante, Nelson. Servicio Agrícola y Ganadero; Chile.Fil: Dart, Ricardo O. Embrapa Solos; BrasilFil: Dell Acqua, Martín. Ministerio de Ganadería, Agricultura y Pesca. Dirección General de Recursos Naturales; UruguayFil: Lencina, Arnulfo. Universidad Nacional de Asunción. Facultad de Ciencias Agrarias; ParaguayFil: Figueredo, Hernán. Sociedad Boliviana de la Ciencia del Suelo; Bolivia.Fil: Fontes, Fernando. Ministerio de Ganadería, Agricultura y Pesca. Dirección General de Recursos Naturales; UruguayFil: Gutierrez Diaz, Joan S. Aarhus University. Faculty of Science and Technology,.Department of Agroecology; DinamarcaFil: Jiménez, Wilmer. Ministerio de Agricultura y Ganadería; Ecuador.Fil: Rodriguez, Dario Martin. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Suelos; ArgentinaFil: Schulz, Guillermo. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Suelos; ArgentinaFil: Tenti Vuegen, Leonardo Mauricio. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Suelos; Argentin

Elastic response of cross-laminated engineered bamboo panels subjected to in-plane loading

© ICE Publishing: All rights reserved. Novel cross-laminated bamboo panels comprising three and five layers (G-XLam3 and G-XLam5) were tested in compression along the main (0°) and the transverse (90°) directions. Linear variable differential transformer (LVDT) and non-contact three-dimensional digital image correlation (DIC) measuring techniques were used separately to measure deformation in the elastic region, and the elastic moduli, Ep C,0 and Ep C,90, were derived. Mean elastic modulus values obtained using LVDTs exhibited a good match with analytically predicted values. In contrast, the elastic values obtained by the DIC method were considerably higher and presented a considerable scatter of results. For instance, the Ep C,0 for G-XLam3 and G-XLam5 panels were 17·22 and 15·67 GPa, and 14·86 and 12·48 GPa, using the DIC and LVDT methods, respectively. In general, G-XLam panels with a fifth of the cross-sectional thickness and twice the density of analogous cross-laminated timber exhibited an approximately two-fold increase in Ep C,0 and Ep C,90. Overall, this research provides guidelines for the assessment and standardisation of the testing procedures for similar engineered bamboo products using contact and non-contact methods and highlights the potential of using G-XLam panels in stiffness-driven applications and in combination with wood for structural purposes

Improving the Latin America and Caribbean Soil Information System (SISLAC) database enhances its usability and scalability.

Spatial soil databases can help model complex phenomena in which soils are a decisive factor – for example, evaluating agricultural potential or estimating carbon storage capacity. The Latin America and Caribbean Soil Information System, SISLAC, is a regional initiative promoted by the Food and Agriculture Organization’s (FAO) Latin America and the Caribbean Soil Partnership to contribute to sustainable management of soil. SISLAC includes data from 49 084 soil profiles distributed unevenly across the continent, making it the region’s largest soil database. In addition, there are other soil databases in the region with about 40 000 soil profiles that can be integrated into SISLAC and improve it. However, some problems hinder its usages, such as the quality of the data and their high dimensionality. The objective of this research is evaluate the quality of the SISLAC data and the other available soil databases to generate a new improved version that meets the minimum quality requirements to be used for different purposes or practical applications. The results show that 15 % of the existing soil profiles had an inaccurate description of the diagnostic horizons and 17 % of the additional profiles already existed in SISLAC; therefore, a total of 32 % of profiles were excluded for these two reasons. Further correction of an additional 4.5 % of existing inconsistencies improved overall data quality. The improved database consists of 66 746 profiles and is available for public use at https://doi.org/10.5281/zenodo.7876731 (Díaz-Guadarrama and Guevara, 2023). This revised version of SISLAC data offers the opportunity to generate information that helps decision-making on issues in which soils are a decisive factor. It can also be used to plan future soil surveys in areas with low density or where updated information is required

Study of Isomeric States in ^{198,200,202,206}Pb and ²⁰⁶Hg Populated in Fragmentation Reactions

Isomeric states in isotopes in the vicinity of doubly-magic 208Pb were populated following reactions of a relativistic 208Pb primary beam impinging on a 9Be fragmentation target. Secondary beams of 198;200;202;206Pb and 206Hg were isotopically separated and implanted in a passive stopper positioned in the focal plane of the GSI Fragment Separator. Delayed γ rays were detected with the Advanced GAmma Tracking Array (AGATA). Decay schemes were re-evaluated and interpreted with shell-model calculations. The momentum-dependent population of isomeric states in the two-nucleon hole nuclei 206Pb/206Hg was found to differ from the population of multi neutron-hole isomeric states in 198;200;202Pb