Ganadería en zonas de amortiguamiento en Chiapas, México: análisis de los capitales de la comunidad

In Chiapas there are 44 natural protected areas (NPA), which suffer constant pressure from the change of land use to agriculture and livestock systems that are related to negative impacts in the NPAs. This document analyzed the influence of livestock production on buffering zones. Thirty-two producers were selected in 3 communities. Information was gathered with semi-structured interviews and participative workshops. The information was analyzed with a modified SWOT analysis comparing the livestock activity with the approach of community capitals. The study evidenced that around 2007 the institutional influence on the expansion and management of agricultural and livestock activities promoted negative impacts on the environment. Because of this, the institutional objectives were focused on the development of sustainable practices. During the institutional accompaniment, training was carried out with different groups of producers; as a result, local organization and the implementation of agriculture and livestock technology (forest shepherding) were fostered. Livestock activity in the three communities has different degrees of development; however, in general they coincide in the unfriendly management of the environment. However, institutional intervention has influenced changes in the productive system, directed at implementing more sustainable practices. It is considered that participative and inclusive processes would promote a productive re-culturalization directed at the integral sustainability of the territory.En Chiapas existen 44 áreas naturales protegidas (ANP), las cuales sufren de constante presión por el cambio de uso de suelo a sistemas agropecuarios que son relacionados con impactos negativos en las ANP. Este documento analizó la influencia de la ganadería en zonas de amortiguamiento. Se eligieron 32 productores en 3 comunidades. Se recabó información con entrevistas semi-estructuradas y talleres participativos. La información fue analizada con un FODA modificado contrastando la actividad ganadera con el enfoque de capitales de la comunidad. El estudio evidenció que alrededor de 2007 la influencia institucional en la expansión y manejo de las actividades agropecuarias promovieron impactos negativos al ambiente. Debido a esto, los objetivos institucionales se enfocaron al desarrollo de prácticas sostenibles. Durante el acompañamiento institucional se llevaron a cabo capacitaciones a los diversos grupos de productores; como resultado se fomentó la organización local y la implementación de tecnología agropecuaria (sistemas silvopastoriles). La actividad ganadera en las tres comunidades tiene distintos grados de desarrollo; sin embargo, son coincidentes de manera general en el manejo poco amigable con el ambiente. No obstante, la intervención institucional ha influido en cambios del sistema productivo, orientando a implementar prácticas más sostenibles. Se considera que procesos participativos e inclusivos fomentarán una re-culturalización productiva dirigida a la sostenibilidad integral del territorio

Tumor dissociation of highly viable cell suspensions for single-cell omic analyses in mouse models of breast cancer.

Cell preparation with a high rate of viable cells is required to obtain reliable single-cell transcriptomic and epigenomic data. This protocol describes a technique for digestion and single-cell isolation from mouse mammary tumors to achieve ∼90% of viable cells, which can be subsequently processed in a diverse array of high-throughput single-cell "omic platforms," both in an unbiased manner or after selection of a specific cell population. For complete details on the use and execution of this protocol, please refer to Valdes-Mora et al. (2021)

The ellipse law: Kirchhoff meets dislocations

In this paper we consider a nonlocal energyIαwhose kernel is obtained by addingto the Coulomb potential an anisotropic term weighted by a parameterα∈R. The caseα= 0corresponds to purely logarithmic interactions, minimised by the circle law;α= 1 correspondsto the energy of interacting dislocations, minimised by the semi-circle law. We show that forα∈(0,1) the minimiser is the normalised characteristic function of the domain enclosed bytheellipseof semi-axes√1−αand√1 +α. This result is one of the very few examples wherethe minimiser of a nonlocal anisotropic energy is explicitly computed. For the proof we borrowtechniques from fluid dynamics, in particular those related to Kirchhoff’s celebrated result thatdomains enclosed by ellipses are rotating vortex patches, calledKirchhoff ellipses

Atomic Multiplet and Charge Transfer Effects in the Resonant Inelastic X-Ray Scattering (RIXS) Spectra at the Nickel L2,3 Edge of NiF2

Resonant inelastic x-ray scattering (RIXS) is used to study the electronic structure of NiF2, which is the most ionic of the nickel compounds. RIXS can be viewed as a coherent two-steps process involving the absorption and the emission of x-rays. The soft x-ray absorption spectrum (XAS) at the metal L2,3 edge indicate the importance of atomic multiplet effects. RIXS spectra at L2,3 contain clearly defined emission peaks corresponding to d-excited states of Ni2+ at energies few eV below the elastic emission, which is strongly suppressed. These results are confirmed by atomic multiplet calculations using the Kramers-Heisenberg formula for RIXS processes. For larger energy losses, the emission spectra have a broad charge-transfer peak that results from the decay of hybridized Ni(3d)-F(2p) valence states. This is confirmed by comparison of the absorption and emission spectra recorded at the nickel L and fluorine K edges with F p and Ni d partial density of states using LDA + U calculations

Improved copper–epoxy adhesion by laser micro- and nano-structuring of copper surface for thermal applications

The objective of this work is the enhancement of metal-to-metal bonding to provide high thermal conductivity together with electrical insulation, to be used as heat sinks at room and cryo-genic temperatures. High thermal conductive metal (copper) and epoxy resin (Stycast 2850FT) were used in this study, with the latter also providing the required electrical insulation. The copper surface was irradiated with laser to induce micro- and nano-patterned structures that result in an improvement of the adhesion between the epoxy and the copper. Thus, copper-to-copper bonding strength was characterized by means of mechanical tensile shear tests. The effect of the laser processing on the thermal conductivity properties of the Cu/epoxy/Cu joint at different temperatures, from 10 to 300 K, is also reported. Using adequate laser parameters, it is possible to obtain high bonding strength values limited by cohesive epoxy fracture, together with good thermal conductivity at ambient and cryogenic temperatures. © 2021 by the authors. Licensee MDPI, Basel, Switzerland

Advancements in 3D Cell Culture Systems for Personalizing Anti-Cancer Therapies.

Over 90% of potential anti-cancer drug candidates results in translational failures in clinical trials. The main reason for this failure can be attributed to the non-accurate pre-clinical models that are being currently used for drug development and in personalised therapies. To ensure that the assessment of drug efficacy and their mechanism of action have clinical translatability, the complexity of the tumor microenvironment needs to be properly modelled. 3D culture models are emerging as a powerful research tool that recapitulates in vivo characteristics. Technological advancements in this field show promising application in improving drug discovery, pre-clinical validation, and precision medicine. In this review, we discuss the significance of the tumor microenvironment and its impact on therapy success, the current developments of 3D culture, and the opportunities that advancements that in vitro technologies can provide to improve cancer therapeutics

Efficiency Maximization of a Jet Pump for an Hydraulic Artificial Lift System

In science and engineering, mathematical modeling serves as a tool to understand processes and systems acting as a testing bed for several hypotheses. The selection of a specific model, as well as its variables and parameters, depends on the nature of the system under analysis and the acceptable simplifying assumptions. Therefore, it must allow for a good fit between both the hypothesis and the available data. Opposite to other design approaches based on experimental data or/and complex models, this work presents a simpler numerical design method for efficiency maximization of an Hydraulic Jet Pump (HJP) for oil-well extraction process, considering its hydraulic and geometric parameters. The design process consists in setting and solving a constrained non-linear optimization problem by taking into account the hydraulic model of the HJP in terms four design variables: throat area, nozzle area, injection flow, and injection pressure to the oil-well. The objective function of this case aims to maximize the HJP's efficiency avoiding to approach cavitation condition as well fulfilling technical constraints. A numerical technique, Differential Evolution Algorithm (DEA), has been implemented to solve the optimization problem. The proposed methodology leads to a solution set by considering only commercial geometries and feasible operating conditions for the HJP, which facilitates its practical implementation. A set of ten oil-wells with land production data, operating in the southeaster of Mexico, is used to compare and validate several Jet pump designs, i. e., through comparison with actual oil-well's operation condition.Peer Reviewe

Evaluación de algunos parámetros de calidad del agua en un sistema cerrado de recirculación para la acuicultura, sometido a diferentes cargas de biomasa de peces

Utilizing different loadings of biomass of the Nile Tilapia Oreochromis niloticus and rainbow trout Oncorhynchus mykiss, some water quality parameters were evaluated in a closed aquaculture recirculating system. The systems is integrated by six culture tanks, a sedimentation cistern, two submerged bio-filters, a fast sand filter, two pumps, a reconditioning-water reservoir and a unit of ultraviolet light lamps. Fishes were fed twice a day for 120 days with 2% of their total biomass. The following water quality parameters were recorded: water temperature, dissolved oxygen, pH, total ammonium nitrogen (TAN), ammonia, nitrate and chemical oxygen demand. The data were analyzed with a one-way ANOVA to determine statistical differences in the components of the system. The average values of TAN and nitrate indicated a high efficiency of the nitrification process at different fish loading of biomass. About 50% of TAN and more than 90% of ammonia was stripped into the atmosphere and this explains the low levels measured in the other components of the system. Other causes that contribute to the removal of nitrogen compounds were the assimilation by microorganism accumulated in the bottom of the sedimentation tank and the absorption and adsorption by the sludge. Results showed that the water quality parameters were satisfactory for 99% survivorship and an acceptable growth rate for both fish species.El objetivo de este estudio, fue evaluar algunos parámetros de calidad del agua en un sistema cerrado de recirculación utilizado en la acuicultura, sometido a distintas cargas de biomasa de Tilapia del NiloOreochromis niloticus y de trucha arco iris Oncorhynchus mykiss. El sistema consiste de seis estanques de cultivo, una cisterna de sedimentación, dos piletas con biofiltros sumergidos, un filtro de arena rápido, dos bombas, una pileta de reacondicionamiento y una unidad de lámparas de luz ultravioleta. Los peces fueron alimentados durante 120 días dos veces al día con el 2% de su biomasa total. Se registraron los siguientes parámetros de calidad del agua: temperatura, oxígeno disuelto, pH, nitrógeno amoniacal total (NAT), amoniaco, nitrato y demanda química de oxígeno. Los datos se analizaron con un ANDEVA de una sola vía para detectar diferencias significativas entre los componentes del sistema. Los valores promedio de NAT y nitrato indicaron una alta eficiencia en los procesos de nitrificación, aún cuando el sistema fue sometido a diferentes cargas de biomasa de peces. Los bajos valores detectados de NAT y amoniaco se debieron al arrastre eficiente hacia la atmósfera (50% NAT y más del 90% respectivamente). Otras posibles causas que contribuyeron a la eliminación de los compuestos nitrogenados, fueron la asimilación por microorganismos presentes en los lodos acumulados en la cisterna de sedimentación, además de la absorción y la adsorción por los lodos. Los resultados mostraron que la calidad del agua mantenida en el sistema permitió el 99% de sobrevivencia de ambas especies y una tasa de crecimiento aceptable

Impact of Sexualized Substance Use and Other Risk Practices on HCV Microelimination in gbMSM Living with HIV: Urgent Need for Targeted Strategies

In the original publication of the article, the article funding note was incorrectly published, the correct one should read as: This study has been funded by Instituto de Salud Carlos III through the project ‘‘PI18/00583’’ and co-funded by European Regional Development Fund ‘‘A way to make Europe’’. This has been corrected in this paper. © The Author(s) 2022

The influence of Ga+^+-irradiation on the transport properties of mesoscopic conducting thin films

We studied the influence of 30keV Ga$^+$-ions -- commonly used in focused ion beam (FIB) devices -- on the transport properties of thin crystalline graphite flake, La$_{0.7}$Ca$_{0.3}$MnO$_3$ and Co thin films. The changes of the electrical resistance were measured in-situ during irradiation and also the temperature and magnetic field dependence before and after irradiation. Our results show that the transport properties of these materials strongly change at Ga$^+$ fluences much below those used for patterning and ion beam induced deposition (IBID), limiting seriously the use of FIB when the intrinsic properties of the materials of interest are of importance. We present a method that can be used to protect the sample as well as to produce selectively irradiation-induced changes.Comment: 14 pages, 11 figures, will be published in Nanotechnology 201