Proceedings of the 8th World Congress on Conservation Agriculture

Under the banner: The Future of Farming – Profitable and Sustainable Farming with Conservation Agriculture, the 8WCCA highlighted the global contribution of Conservation Agriculture towards achieving these outcomes. It also explored how CA land use can help to address humankind’s major global challenges of climate change, environmental degradation and food security while safeguarding the livelihoods of small and large-scale farmers. The proven benefits of CA in terms of erosion control, carbon sequestration, biodiversity regeneration, and improved water and nutrient cycling are all contributing to the achievement of the manifold objectives of the international conventions and agreements including the Sustainable Development Goals, European Green Deal and F2F Strategy

Estudio de la biocompatibilidad in vitro de formulaciones acrílicas autocurables portadoras de bisfosfonatos de nueva síntesis

En este trabajo se presenta el estudio de la biocompatibilidad in vitro, empleando cultivos celulares de fibroblastos embrionarios humanos, de tres sistemas acrílicos de liberación controlada de bisfosfonatos (BFs). Estos sistemas, basados en metacrilato de metilo (MMA), metacrilato de vitamina E (MVE) y trietilenglicol dimetacrilato (TEGDMA), han sido diseñados para su aplicación en el tratamiento de enfermedades caracterizadas por una elevada resorción osteoclástica. En su preparación se ha empleado un BP comercializado (alendronato; ALN) y dos de nueva síntesis, pertenecientes a la segunda y tercera generaciones, el ácido 1-hidroxi-2-[4-aminofenil]etano-1,1-difosfónico (APBP) y el ácido 1-hidroxi-2-[3-indolil]etano-1,1-difosfónico (IBP), respectivamente. La citotoxicidad de MVE ha sido notablemente inferior a la medida para TEGDMA. La citotoxicidad de APBP e IBP se ha comparado con la de ALN, obteniéndose unos valores para la concentración IC50, de15,56, 9,86 y 6,25 mmol/l para APBP, ALN e IBP, respectivamente. Los niveles de citotoxicidad liberada han sido superiores para la formulación portadora de ALN, situándose a continuación los cementos cargados con IBP y APBP. Cuando los cultivos se han establecido sobre la superficie de las formulaciones, se han detectado unos niveles de proliferación celular y adhesión superiores para los sistemas de liberación de IBP y APBP, siendo además inferior en estos casos la mortalidad celular.This paper reports the in vitro biocompatibility study, using human embryonic fibroblast cultures, of three acrylic systems for controlled release of bisphosphonates (BFs). These systems, that are based on methyl methacrylate (MMA), vitamin E methacrylate (MVE) and triethyleneglycol dimethacrylate (TEGDMA), have been designed for its application in the treatment of pathologies characterized by a high osteoclastic resorption. A commercial BP (alendronate; ALN) and two novel BPs, belonging to the second and third generations, 1-hydroxy-2-[4-aminophenyl]ethane-1,1-diphosphonic acid (APBP) and 1-hydroxy-2-[3-indolyl]ethane-1,1-diphosphonic acid (IBP), respectively, have been used in their preparation. The cytotoxicity of MVE has been notably lower than that measured for TEGDMA. Cytotoxicity of APBP and IBP was evaluated along with that of ALN, and the following values of the IC50, concentration were obtained for APBP, ALN and IBP respectively: 15.56, 9.86 and 6.25 mmol/l. The cytotoxicity levels obtained from the extracts of the cured systems were higher for the formulation containing ALN, followed by the cements loaded with IBP and APBP. When the cultures were seeded directly on the formulations surface, higher levels of cellular proliferation and adhesion were obtained for the systems containing IBP and APBP, the cellular mortality being also inferior in these cases

The Age, Stellar Content and Star Formation Timescale of the B59 Dense Core

We have used moderate resolution, near-infrared spectra from the SpeX spectrograph on the NASA Infrared Telescope facility to characterize the stellar content of Barnard 59 (B59), the most active star-forming core in the Pipe Nebula. Measuring luminosity and temperature sensitive features in the spectra of 20 candidate YSOs, we identified likely background giant stars and measured each star's spectral type, extinction, and NIR continuum excess. We find that B59 is composed of late type (K4-M6) low-mass (0.9--0.1 M_sun) YSOs whose median stellar age is comparable to, if not slightly older than, that of YSOs within the Rho Oph, Taurus, and Chameleon star forming regions. Deriving absolute age estimates from pre-main sequence models computed by D'Antona et al., and accounting only for statistical uncertainties, we measure B59's median stellar age to be 2.6+/-0.8 Myrs. Including potential systematic effects increases the error budget for B59's median (DM98) stellar age to 2.6+4.1/-2.6 Myrs. We also find that the relative age orderings implied by pre-main sequence evolutionary tracks depend on the range of stellar masses sampled, as model isochrones possess significantly different mass dependencies. The maximum likelihood median stellar age we measure for B59, and the region's observed gas properties, suggest that the B59 dense core has been stable against global collapse for roughly 6 dynamical timescales, and is actively forming stars with a star formation efficiency per dynamical time of ~6%. This maximum likelihood value agrees well with recent star formation simulations that incorporate various forms of support against collapse, such as sub-critical magnetic fields, outflows, and radiative feedback from protostellar heating. [abridged]Comment: 20 pages, 12 figures, accepted for publication in the Astrophysical Journal; updated to amend acknowledgment

A Simple Perspective on the Mass-Area Relationship in Molecular Clouds

Despite over 30 years of study, the mass-area relationship within and among clouds is still poorly understood both observationally and theoretically. Modern extinction datasets should have sufficient resolution and dynamic range to characterize this relationship for nearby molecular clouds, although recent papers using extinction data seem to yield different interpretations regarding the nature and universality of this aspect of cloud structure. In this paper we try to unify these various results and interpretations by accounting for the different ways cloud properties are measured and analyzed. We interpret the mass-area relationship in terms of the column density distribution function and its possible variation within and among clouds. We quantitatively characterize regional variations in the column density PDF. We show that structures both within and among clouds possess the same degree of "universality", in that their PDF means do not systematically scale with structure size. Because of this, mass scales linearly with area.Comment: 10 pages, 8 figures, MNRAS in pres

MTOC translocation modulates IS formation and controls sustained T cell signaling

The translocation of the microtubule-organizing center (MTOC) toward the nascent immune synapse (IS) is an early step in lymphocyte activation initiated by T cell receptor (TCR) signaling. The molecular mechanisms that control the physical movement of the lymphocyte MTOC remain largely unknown. We have studied the role of the dynein–dynactin complex, a microtubule-based molecular motor, in the process of T cell activation during T cell antigen–presenting cell cognate immune interactions. Impairment of dynein–dynactin complex activity, either by overexpressing the p50-dynamitin component of dynactin to disrupt the complex or by knocking down dynein heavy chain expression to prevent its formation, inhibited MTOC translocation after TCR antigen priming. This resulted in a strong reduction in the phosphorylation of molecules such as ζ chain–associated protein kinase 70 (ZAP70), linker of activated T cells (LAT), and Vav1; prevented the supply of molecules to the IS from intracellular pools, resulting in a disorganized and dysfunctional IS architecture; and impaired interleukin-2 production. Together, these data reveal MTOC translocation as an important mechanism underlying IS formation and sustained T cell signaling

Relationship Among Sleep Quality, Sleep Habits and School Adjustment in Adolescents From an Urban District of Galicia

[Resumen] Fundamentos: La duración y calidad del sueño están relacionadas en los adolescentes con su estado emocional y rendimiento académico. El objetivo del estudio fue evaluar la calidad del sueño en un grupo de jóvenes y explorar su relación con el ajuste y rendimiento escolar. Métodos: Se realizó un estudio descriptivo-transversal, con 56 adolescentes entre 13 y 17 años de un instituto de educación secundaria de un distrito de La Coruña, durante el curso 2016-2017. Los participantes cumplimentaron el Índice de Calidad del Sueño de Pittsburgh (ICSP), la Escala Breve de Ajuste Escolar y un breve cuestionario sobre hábitos de sueño y calificaciones académicas. Realizamos el análisis descriptivo y diferentes pruebas comparativas o de asociación estadística por métodos paramétricos o no paramétricos según cada variable, considerándose significativos valores de p<0,10. Resultados: El 35,7% de la muestra se clasificó como mala durmiente y la somnolencia fue la variable más alterada del ICSP. Las mujeres dormían significativamente menos que los varones, aunque ambos retrasaban 100 minutos el sueño durante el fin de semana. Ser buen o mal durmiente no afectó al rendimiento académico. El ajuste escolar fue satisfactorio globalmente. Las variables que expresaron desajuste en la interacción con los profesores y compañeros de clase, así como la realización de tareas escolares, se relacionaron con la disfunción diurna. Conclusiones: La somnolencia es el problema más relevante en el grupo de malos durmientes. Esta puede influir negativamente en el ajuste escolar y en la motivación para las actividades escolares de todos los adolescentes, siendo frecuente y subestimada en la mayoría de los casos.[Abstract] Background: The duration and the sleep quality are related to the emotional status and the academic performance in adolescents. The objective of this study was to evaluate the quality of sleep in a group of adolescents, and to explore its relationship with school adjustment and performance. Methods: A cross-sectional descriptive study was made with 56 adolescents aged 13-17 years from a high school institute in an urban district of La Coruña city was performed during the scholar´s year 2016-2017. The participants completed the Pittsburgh Sleep Quality Index (ICSP) and the Brief School Adjustment Scale, and a brief questionnaire about their sleep habits and school scores. Descriptive analysis and different comparative parametric or not parametric statistical tests were applied according to type of variable; statistical significant value was considerate for p<0.10. Results: The 35.7% of sample was poor sleepers and sleepiness was the most altered variable in ICSP. The female participants tended to sleep less than the male participants, and all of them went to sleep 100 minutes later on the weekend. Being a good or bad sleeper did not affect academic performance. Globally the school adjustment was satisfactory. Diurnal dysfunction was related to a worse adolescent-teacher and adolescent-classmate relationship. Diurnal dysfunction was also related to a poor motivation to perform academic tasks. Conclusions: Sleepiness is the most relevant problem in poor sleepers. Sleepiness has a negative influence on school adjustment and motivation for school activities of all adolescents; it is frequent and underestimated in most of the cases

Hierarchical Stellar Structures in the Local Group Dwarf Galaxy NGC 6822

We present a comprehensive study of the star cluster population and the hierarchical structure in the clustering of blue stars with ages <~ 500 Myr in the Local Group dwarf irregular galaxy NGC 6822. Our observational material comprises the most complete optical stellar catalog of the galaxy from imaging with the Suprime-Cam at the 8.2-m SUBARU Telescope. We identify 47 distinct star clusters with the application of the nearest-neighbor density method to this catalog for a detection threshold of 3sigma above the average stellar density. The size distribution of the detected clusters can be very well approximated by a Gaussian with a peak at ~ 68 pc. Their cluster mass function is fitted very well by a power-law with index alpha ~ 1.5 +/- 0.7, consistent with other Local Group galaxies and the cluster initial mass function. The application of the nearest-neighbor density method for various density thresholds, other than 3sigma, enabled the identification of stellar concentrations in various length-scales. The stellar density maps constructed with this technique provide a direct proof of hierarchically structured stellar concentrations in NGC 6822. We illustrate this hierarchy by the so-called "dendrogram" of the detected stellar structures, which demonstrates that most of the detected structures split up into several substructures over at least three levels. We quantify the hierarchy of these structures with the use of the minimum spanning tree method. The morphological hierarchy in stellar clustering, which we observe in NGC 6822 resembles that of the turbulent interstellar matter, suggesting that turbulence on pc- and kpc-scales has been probably the major agent that regulated clustered star formation in NGC 6822.Comment: 18 pages in ApJ two-column format, 13 figure

Psychological Impact of COVID-19 Lockdown on Well-being: Comparisons between People with Obesity, with Diabetes and without Diseases

Introduction: Obesity and type 2 diabetes mellitus are two chronic diseases most associated with hospitalizationsand deaths from COVID-19.Background: This study compared psychological impact of COVID-19 lockdown in people with obesity, people with type 2 diabetes (T2D) and people without diseases, and determined the factors associated with well-being.Materials and methods: An online survey on negative affect, attitudes, social support and sharing, coping,well-being, and eating behavior was conducted in 157 people with obesity, 92 with type 2 diabetes and 288without diseases.Results: People with obesity were the most worried of getting infected (70%) or dying (64%) and had the highest levels of emotional eating. People with T2D showed better coping strategies and higher well-being. Negative affect, worries about COVID-19 consequences and uncontrolled eating had negative impact, but social support, social sharing, and coping contributed positively (p &lt; 0.001) to well-being. A 48.7% of people with obesity experienced more difficulties to adhere to treatment compared to only 11.1% of people with T2D.Conclusions: People with obesity had less well-being and more COVID-19 worries and emotional eating than people with T2D and without diseases. Well-being depends on negative affect, worries and eating behavior. Future research about the impact in long-term on weight and health status in patients with chronic diseases is needed

DEAE-chitosan nanoparticles as a pneumococcus-biomimetic material for the development of antipneumococcal therapeutics

13 p.-7 fig.Advanced biomaterials provide an interesting and versatile platform to implement new and more effective strategies to fight bacterial infections. Chitosan is one of these biopolymers and possesses relevant features for biomedical applications. Here we synthesized nanoparticles of chitosan derivatized with diethylaminoethyl groups (ChiDENPs) to emulate the choline residues in the pneumococcal cell wall and act as ligands for choline-binding proteins (CBPs). Firstly, we assessed the ability of diethylaminoethyl (DEAE) to sequester the CBPs present in the bacterial surface, thus promoting chain formation. Secondly, the CBP-binding ability of ChiDENPs was purposed to encapsulate a bio-active molecule, the antimicrobial enzyme Cpl-711 (ChiDENPs-711), with improved stability over non-derivatized chitosan. The enzyme-loaded system released more than 90% of the active enzybiotic in ≈ 2 h, above the usual in vivo half-life of this kind of enzymes. Therefore, ChiDENPs provide a promising platform for the controlled release of CBP-enzybiotics in biological contexts.This study was funded by a grant from the Ministerio de Economía y Competitividad (MINECO-FEDER, SAF2017-88664-R) and the Ministerio de Ciencia e Innovación (MAT2017-84277-R, PID2019-105126RB-I00). F. J. Caro acknowledges financial support from CONACyT (Mexico) through the scholarship ‘Apoyo para estancias postdoctorales en el extranjero vinculadas a la consolidación de grupos de investigación y fortalecimiento del Posgrado nacional’. Additional funding was provided by the Centro de Investigación Biomédica en Red de Enfermedades Respiratorias (CIBERES) and Centro de Investigación Biomédica en Red en Bioingeniería, Biomateriales y Nanomedicina (CIBER-BBN), an initiative of the Instituto de Salud Carlos III.Peer reviewe