Transformers and Large Language Models for Chemistry and Drug Discovery

Language modeling has seen impressive progress over the last years, mainly prompted by the invention of the Transformer architecture, sparking a revolution in many fields of machine learning, with breakthroughs in chemistry and biology. In this chapter, we explore how analogies between chemical and natural language have inspired the use of Transformers to tackle important bottlenecks in the drug discovery process, such as retrosynthetic planning and chemical space exploration. The revolution started with models able to perform particular tasks with a single type of data, like linearised molecular graphs, which then evolved to include other types of data, like spectra from analytical instruments, synthesis actions, and human language. A new trend leverages recent developments in large language models, giving rise to a wave of models capable of solving generic tasks in chemistry, all facilitated by the flexibility of natural language. As we continue to explore and harness these capabilities, we can look forward to a future where machine learning plays an even more integral role in accelerating scientific discovery

Communication Lab Peer Facilitators: What\u27s in It for Them?

Peer tutors have been used extensively within the communication discipline to enhance students\u27 learning experiences (Hill, 1981; Webb & Lane, 1986). Research suggests that peer tutoring can have positive rewards for tutors and tutees (Goodland & Hurst, 1989; Topping, 1996). However, there is little to no research that explores the benefits received by peer tutors who run small group communication lab sessions for basic communication course students. The qualitative data from focus group indicate that peer facilitators experienced: 1) self-development in terms of their self-esteem, confidence, and respect from themselves and others; 2) improved public speaking skills and better interpersonal relationship with family and friends, other peer facilitators, and individuals in positions of authority; and 3) external rewards in that they felt better prepared for post baccalaureate programs and to compete in the workplace. The results of this study may be used as a basis for more in-depth research on the benefits derived from the peer facilitation experience in the basic communication course

Ortuzar, Mónica: Beuysiana. Universidad de Vigo. Servicio de Publicaciones, Vigo, 2011, 149 pp.

Recensió

Evidence of Skyrmion-Tube Mediated Magnetization Reversal in Modulated Nanowires

Magnetic nanowires, conceived as individual building blocks for spintronic devices, constitute a well-suited model to design and study magnetization reversal processes, or to tackle fundamental questions, such as the presence of topologically protected magnetization textures under particular conditions. Recently, a skyrmion-tube mediated magnetization reversal process was theoretically reported in diameter modulated cylindrical nanowires. In these nanowires, a vortex nucleates at the end of the segments with larger diameter and propagates, resulting in a first switching of the nanowire core magnetization at small fields. In this work, we show experimental evidence of the so-called Bloch skyrmion-tubes, using advanced Magnetic Force Microscopy modes to image the magnetization reversal process of FeCoCu diameter modulated nanowires. By monitoring the magnetic state of the nanowire during applied field sweeping, a detected drop of magnetic signal at a given critical field unveils the presence of a skyrmion-tube, due to mutually compensating stray field components. That evidences the presence of a skyrmion-tube as an intermediate stage during the magnetization reversal, whose presence is related to the geometrical dimensions of the cylindrical segments

Magnetic behavior of NiCu nanowire arrays: Compositional, geometry and temperature dependence

Arrays of Ni100-xCux nanowires ranging in composition 0¿=¿x¿=¿75, diameter from 35 to 80¿nm, and length from 150¿nm to 28¿µm have been fabricated by electrochemical co-deposition of Ni and Cu into self-ordered anodic aluminum oxide membranes. As determined by X-ray diffraction and Transmission Electron Microscopy, the crystalline structure shows fcc cubic symmetry with [111] preferred texture and preferential Ni or Cu lattice depending on the composition. Their magnetic properties such as coercivity and squareness have been determined as a function of composition and geometry in a Vibrating Sample Magnetometer in the temperature range from 10 to 290¿K for applied magnetic fields parallel and perpendicular to the nanowires axis. Addition of Cu into the NiCu alloy up to 50% enhances both parallel coercivity and squareness. For the higher Cu content, these properties decrease and the magnetization easy axis becomes oriented perpendicular to the wires. In addition, coercivity and squareness increase by decreasing the diameter of nanowires which is ascribed to the increase of shape anisotropy. The temperature dependent measurements reflect a complex behavior of the magnetic anisotropy as a result of energy contributions with different evolution with temperature

Efeito da bracatinga (Mimosa scabrella) na produção de matéria seca de pastagem sob sistema silvipastorial.

Edición de las Memorias de la 22a. Reunión ALPA, 2011, Montevideo. E68 Poster

Plasmonic coupling in closed-packed ordered gallium nanoparticles

Plasmonic gallium (Ga) nanoparticles (NPs) are well known to exhibit good performance in numerous applications such as surface enhanced fluorescence and Raman spectroscopy or biosensing. However, to reach the optimal optical performance, the strength of the localized surface plasmon resonances (LSPRs) must be enhanced particularly by suitable narrowing the NP size distribution among other factors. With this purpose, our last work demonstrated the production of hexagonal ordered arrays of Ga NPs by using templates of aluminium (Al) shallow pit arrays, whose LSPRs were observed in the VIS region. The quantitative analysis of the optical properties by spectroscopic ellipsometry confirmed an outstanding improvement of the LSPR intensity and full width at half maximum (FWHM) due to the imposed ordering. Here, by engineering the template dimensions, and therefore by tuning Ga NPs size, we expand the LSPRs of the Ga NPs to cover a wider range of the electromagnetic spectrum from the UV to the IR regions. More interestingly, the factors that cause this optical performance improvement are studied with the universal plasmon ruler equation, supported with discrete dipole approximation simulations. The results allow us to conclude that the plasmonic coupling between NPs originated in the ordered systems is the main cause for the optimized optical responseThe research is supported by the MINECO (CTQ2014-53334-C2-2-R, CTQ2017-84309-C2-2-R and MAT201676824-C3-1-R) and Comunidad de Madrid (P2018/NMT4349 and S2018/NMT-4321 NANOMAGCOST) projects. ARC acknowledges Ramón y Cajal program (under contract number RYC-2015-18047

Spin configuration in isolated FeCoCu nanowires modulated in diameter

Cylindrical Fe28Co67Cu5 nanowires modulated in diameter between 22 and 35 nm are synthesized by electroplating into the nanopores of alumina membranes. High-sensitivity MFM imaging (with a detection noise of 1 µN m-1) reveals the presence of single-domain structures in remanence with strong contrast at the ends of the nanowires, as well as at the transition regions where the diameter is modulated. Micromagnetic simulations suggest that curling of the magnetization takes place at these transition sites, extending over 10–20 nm and giving rise to stray fields measurable with our MFM. An additional weaker contrast is imaged, which is interpreted to arise from inhomogeneities in the nanowire diameter

Comunidades vegetales y ambiente en el ecotono boreal entre los distritos patagónicos Central y Occidental (Río Negro, Argentina)

Con el objetivo de describir la vegetación en el extremo norte del ecotono entre los distritos patagónicos Central y Occidental (Río Negro, Argentina) se obtuvieron 58 censos florísticos distribuidos en los principales paisajes. Se registraron las coordenadas geográficas y algunos parámetros topográficos y edáficos. Las precipitaciones se obtuvieron por interpolación a partir de 14 estaciones. Los censos se clasificaron con el método TWINSPAN, y la composición florística de las comunidades obtenidas se comparó con la vegetación representativa de distintas unidades fitogeográficas descriptas para otras zonas, cercanas al área de estudio. Los principales gradientes florísticos se obtuvieron con un Análisis de Correspondencia, y las relaciones vegetación-ambiente se detectaron con un Análisis Canónico de Correspondencia. Se delimitaron 6 comunidades: 1) Estepa graminoso-arbustiva de Poa ligularis y Junellia mulinoides, 2) Estepa graminoso-arbustiva de Mulinum spinosum y Stipa speciosa, 3) Estepa arbustivo-graminosa de Stipa humilis y Nassauvia glomerulosa, 4) Estepa arbustiva de Nassauvia glomerulosa, Senecio filaginoides y Stipa humilis, 5) Estepa arbustivo-graminosa de Prosopis denudans, Atriplex lampa y Stipa humilis, 6) Estepa arbustiva de Atriplex lampa y Chuquiraga avellanedae. Estas comunidades se ordenaron en un gradiente principal asociado a la altitud. Las dos primeras fueron exclusivas de las mesetas de basalto, y representan la vegetación del Distrito Occidental descripto para otras zonas de Patagonia. Las comunidades 3 y 4, a menores altitudes, representan una transición hacia una unidad fitogeográfica más xerófila, el Distrito Central. Las comunidades 5 y 6, en los sitios más bajos, están dominadas por especies características del Distrito Central, con elementos de la Provincia Fitogeográfica del Monte. A medida que disminuye la altitud los suelos son más profundos, más alcalinos y de texturas más finas.With the objective of describing the vegetation of the northern extreme of the ecotone between the Central and Occidental Patagonian districts (Río Negro, Argentina), 58 floristic samples distributed in the main landscapes of the region were obtained. Their geographic coordinates, and topographic and edaphic parameters were registered. Precipitations were obtained by interpolation from 14 stations. Samples were classified using TWINSPAN method, and floristic composition of the different community types was compared with the vegetation representative of other regions, situated close to the study area. Main floristic gradients were obtained with Correspondence Analysis and vegetation-environment relations were detected with Canonical Correspondence Analysis. Six communities were delimited: 1) Grass-shrub steppe of Poa ligularis and Junellia mulinoides, 2) Grass-shrub steppe of Mulinum spinosum and Stipa speciosa, 3) Shrub-grass steppe of Stipa humilis and Nassauvia glomerulosa, 4) Shrub steppe of Nassauvia glomerulosa, Senecio filaginoides and Stipa humilis, 5) Shrub-grass steppe of Prosopis denudans, Atriplex lampa and Stipa humilis, 6) Shrub steppe of Atriplex lampa and Chuquiraga avellanedae. These communities were ordinated in a main gradient associated with altitude. The first two communities were exclusive of the basaltic plateaus, and represent the vegetation of the Occidental District described for other regions of Patagonia. Communities 3 and 4, at lower altitudes, represent a transition towards a more xerophilous phytogeographic unit, the Central District, and communities 5 and 6, in the lowest sites, are dominated by species characteristic of the Central District with Monte Phytogeographical Province elements. As altitude decreases, soils are deeper, more alkaline, and with finer textures

Proposals for Innovation and Improvement of the Quality of Life in Caprine Pastoralist Communities of Subsistence in the Monte Desert, Argentina

In a satisfactory alliance between the main environmental policy organizations and the academy, the National Observatory on Land Degradation and Desertification (ONDTyT) is created. The ONDTyD provides information regarding status and trends of land degradation/desertification in order to promote prevention and mitigation measures used for advising public and private decision-makers in Argentina. It is based in the development of 17 Pilot Sites that constitutes the local level network, providing bio-physical and socio-economic indicators of land degradation. In this network the pilot site of the Monte, the largest dry region of Argentina (Lavalle desert, Mendoza), aims to improve the living conditions of native communities dedicated to subsistence goat farming, located below the poverty line. Precipitation ranges from 80-100 mm/year, strongly affecting productive activities. The proposal includes innovative traits in an area whose natural resources have been devastated. It is framed within a conception of rural territory development generating sustainable development strategies of rural indigenous communities, improve the status of the ecosystem through an integral management of natural and cultural resources, and improve socioeconomic conditions of inhabitants, compatibilizing ecosystem regeneration with investment in infrastructure and services, diversification of productive activities and generation of employment. An interdisciplinary group designed the proposal and the integrated desertification assessment in the fields with active community participation through their knowledge, land and livestock. The pilot case can be replicated throughout the territory. The work combines participatory and integrated methodologies, showing that the Observatory is a successful example of partnership building between the political and scientific-technological sectors in Argentina