Optimización multi-objetivo del desempeño y consumo energético de procesos de destilación intensificados para sistemas cuaternarios

Este artículo presenta el diseño y optimización multiobjetivo de sistemas de destilación convencionales e intensificados para la separación de mezclas cuaternarias. Tres casos de estudio fueron utilizados para demostrar las ventajas y limitaciones de las configuraciones de destilación convencionales, nonsharp e intensificadas en términos de la optimización simultánea de la composición de un compuesto clave y el consumo energético para su separación. Los resultados indican que el desempeño de estos esquemas de destilación puede variar sustancialmente cuando la pureza y eficiencia energética del proceso son los objetivos en conflicto. La secuencia convencional de destilación directa puede igualar o incluso mejorar el desempeño de algunos procesos intensificados en las mezclas analizadas. En este trabajo se resalta la importancia de realizar un diseño robusto de secuencias de separación multicomponente con la finalidad de evaluar sus ventajas y limitaciones

Extreme salinity as a challenge to grow potatoes under Mars-like soil conditions: targeting promising genotypes.

One of the future challenges to produce food in a Mars environment will be the optimization of resources through the potential use of the Martian substratum for growing crops as a part of bioregenerative food systems. In vitro plantlets from 65 potato genotypes were rooted in peat-pellets substratum and transplanted in pots filled with Mars-like soil from La Joya desert in Southern Peru. The Mars-like soil was characterized by extreme salinity (an electric conductivity of 19.3 and 52.6 dS m−1 under 1 : 1 and saturation extract of the soil solution, respectively) and plants grown in it were under sub-optimum physiological status indicated by average maximum stomatal conductance <50 mmol H2O m−2 s−1 even after irrigation. 40% of the genotypes survived and yielded (0.3–5.2 g tuber plant−1) where CIP.397099.4, CIP.396311.1 and CIP.390478.9 were targeted as promising materials with 9.3, 8.9 and 5.8% of fresh tuber yield in relation to the control conditions. A combination of appropriate genotypes and soil management will be crucial to withstand extreme salinity, a problem also important in agriculture on Earth that requires more detailed follow-up studies

Academic competence, teacher–student relationship, and violence and victimisation in adolescents: The classroom climate as a mediator

School violence is a serious social and public health problem prevalent worldwide. Alt-hough the relevance of teacher and classroom factors is well established in the literature, few studies have focused on the role of teacher perceptions in school violence and victimisation and the poten-tial mediational role of classroom climate in this relationship. A total of 2399 adolescents (50% girls), aged between 11 and 18 years (M = 14.65, SD = 1.78) and enrolled in five Spanish Secondary Com-pulsory Education schools completed measures of classroom climate, school violence towards peers and perception of peer victimisation, and their teachers informed about their academic competence and the teacher–student relationship. Correlational analyses revealed that whereas academic competence perceived by the teacher was negatively related to overt violence and victimisation, its relationship with pure relational violence was positive. Structural equation modelling analyses showed that variables of classroom climate (involvement, affiliation, and teacher support) perceived by the students functioned as partial mediators between teacher perceptions of academic competence and of teacher–student relationship and violence and victimisation. In the mediational model, teacher perception of academic competence acted as a direct protective factor against violence and victimisation, and teacher perception of teacher–student relationship acted as a direct risk for violence, as well as an indirect protective factor through classroom climate for victimisation. The interpretation of these results points to the importance of the teacher’s subjective perceptions in the prevention of violence and victimisation problems and their practical implications for the classroom climate perceived by students

How the reconstruction of faunal communities in a marine protected area (Columbretes Reserve, western Mediterranean) evidence human and natural impacts on fauna

Reconstruction of marine communities in search of baseline (pristine) conditions is a crucial first step for their future restoration. A recent reconstruction (last century) of the sandy-muddy bottom fauna on the continental shelf of a marine protected area (MPA) was performed in the Columbretes Reserve, including periods after and before the Reserve declaration. The dating of sediments and identification of faunal remains (e.g., shells of benthic bivalves and gastropods and pelagic pteropods) were performed in a core (MC2) at a depth of 87 m in 2018. Radiometric data identified sediments older (below 11 cm) and younger (from the top of the core to 11 cm) than ca. 110 years. Mercury analyses validated the 210Pbxs data at 5–7 cm (1967–1989), with a significant Hg peak that coincided with a period of military activities occurring until 1982 in the Columbretes Islands. Both human and climatic variables affected benthic and pelagic communities. Among the human impacts, the cessation of trawling activity after the declaration of the MPA (1980s) influenced the most dominant benthos (bivalves and gastropods) by i) increases in their abundance and ii) changes in the feeding guilds, with a return to baseline conditions by the increase in filter feeders after trawling cessation vs a high abundance of detritus feeders occurring under high trawling activity. Human activities apparently did not affect diversity levels. In parallel, we also identified some recolonization by Octocorallia since the 1980s. Finally, the increase in the pelagic pteropod Creseis acicula since 1995 at the MC2 station probably indicates the result of warming of surface waters in recent decades. Our study based on core reconstructions provides for the first time an historical perspective of the impact of trawling on marine benthos and the positive effect of conservation measures in marine protected areas.En prens

A Comparative Study between Two Regression Methods on LiDAR Data: A Case Study

Airborne LiDAR (Light Detection and Ranging) has become an excellent tool for accurately assessing vegetation characteristics in forest environments. Previous studies showed empirical relationships between LiDAR and field-measured biophysical variables. Multiple linear regression (MLR) with stepwise feature selection is the most common method for building estimation models. Although this technique has provided very interesting results, many other data mining techniques may be applied. The overall goal of this study is to compare different methodologies for assessing biomass fractions at stand level using airborne Li- DAR data in forest settings. In order to choose the best methodology, a comparison between two different feature selection techniques (stepwise selection vs. genetic-based selection) is presented. In addition, classical MLR is also compared with regression trees (M5P). The results when each methodology is applied to estimate stand biomass fractions from an area of northern Spain show that genetically-selected M5P obtains the best results

First faunistic results on Valencia (Cresques) Seamount, with some ecological considerations

The living and dead fauna of Valencia Seamount, a deep promontory in the middle of the Balearic Basin which summit is at ca. 1100m depth, is described by first time based in a rock dredge perfomed in a sedimentary area of the summit Mount. Surface-feeder polychaetes (the Paraonidae Levinsenia gracilis and Terebellidae as dominant), and taxodont bivalves (Ledella messanensis and Yoldiella ovulum) were the main species of benthos. We found alive remains of the bamboo coral Isidella elongata, a vulnerable, habitat-forming species in the deep Mediterranean. Benthos density was low (0.6 organisms/2 dm3 mud). Thanatocoenosis evidenced a rather moderate diversity on benthic bivalves (11 species) and gastropods (9 species) also dominated by surface deposit feeders. Fish (identified/ quantified from sedimented otoliths) showed diversified and abundant mesopelagic fauna, mainly Myctophidae. More interestingly, we highlighted among benthopelagic fish the occurrence of recruits of Merluccius merluccius, Micromesistius poutassou, or Hymenocephalus italicus, all species that live in the neighboring slopes of the Iberian Peninsula and the Balearic Islands at quite shallower depths (at 100-700 m) than their distribution in the Valencia Seamount summit (1102–1130 m) based on the deposited otoliths found. Some ecological aspects were discussed and the necessity to consider the deep Valencia Seamount as a potential area that should be under protection.En prensa

PPARGC1A gene promoter methylation as a biomarker of insulin secretion and sensitivity in response to glucose challenges

Methylation in CpG sites of the PPARGC1A gene (encoding PGC1-α) has been associated with adiposity, insulin secretion/sensitivity indexes and type 2 diabetes. We assessed the association between the methylation profile of the PPARGC1A gene promoter gene in leukocytes with insulin secretion/sensitivity indexes in normoglycemic women. A standard oral glucose tolerance test (OGTT) and an abbreviated version of the intravenous glucose tolerance test (IVGTT) were carried out in n = 57 Chilean nondiabetic women with measurements of plasma glucose, insulin, and C-peptide. Bisulfite-treated DNA from leukocytes was evaluated for methylation levels in six CpG sites of the proximal promoter of the PPARGC1A gene by pyrosequencing (positions -816, -783, -652, -617, -521 and -515). A strong correlation between the DNA methylation percentage of different CpG sites of the PPARGC1A promoter in leukocytes was found, suggesting an integrated epigenetic control of this region. We found a positive association between the methylation levels of the CpG site -783 with the insulin sensitivity Matsuda composite index (rho = 0.31; p = 0.02) derived from the OGTT. The CpG hypomethylation in the promoter position -783 of the PPARGC1A gene in leukocytes may represent a biomarker of reduced insulin sensitivity after the ingestion of glucose

Diferencias de la presentación y tratamiento en las neoplasias primarias de hígado en un centro de hepatología y un centro oncológico

Introducción y objetivos: El cáncer primario de hígado es un problema de salud pública en México y en el mundo. El trasplante hepático (TH) es el tratamiento ideal para el carcinoma hepatocelular (CHC) temprano. El objetivo fue evaluar las características de los pacientes con CHC y colangiocarcinoma (CC) en dos centros e identificar a los candidatos a trasplante. Material y métodos: Estudio retrospectivo, observacional del 2012 al 2018 en el Centro de Hepatología (CH) y el Centro Universitario contra el Cáncer (CUCC). Se confirmó CHC o colangiocarcinoma intrahepático (CCi) en 109 pacientes, a los CHC se les aplicaron clasificaciones de estadiaje, modelos de selección para trasplante y modelo pronóstico de recidiva post-TH. Resultados: De la población total, 93% (n = 102) eran cirróticos. El 86% (n = 94) tuvo CHC (58% CH y 42% CUCC) y 14% (n = 15) CCi (40% CH y 60% CUCC). En los pacientes con CHC del CH predominó Okuda I-II, clasificación de Barcelona Clinic Liver Cancer (BCLC) A-B y niveles 1,000 ng/mL de AFP. La mitad de la población del CH con CHC cumplía con los criterios para TH, en cambio, en el CUCC solo lo hizo el 23%. Se valoraron 15 pacientes para TH y, a la fecha, se trasplantaron seis