Sobre las diferentes nociones topológicas de complejo y algunas de sus aplicaciones

The main goal of this work is to introduce the different kinds of combinatorial structures used in topological data analysis. It is focused on a detailed description of certain types of simplicial, cubical and cellular complexes, namely flag complexes, Cech complexes, Vietoris-Rips complexes, Witness complexes, Delaunay complexes and Alpha complexes will be considered. Additionally, persistent homology will be introduced as the main tool to extract relevant topological information from data sets via the above mentioned kinds of complexes.Universidad de Sevilla. Grado en Matemática

One-Pot Synthesis of Oxidation-Sensitive Supramolecular Gels and Vesicles

A.D.-C. and G.B. acknowledge the Royal Society (Newton International Fellowship scheme 2017.NF171487) and EU H2020 MSCA-IF-792957 SPeNTa-Brain. The authors thank the ERC for the consolidator award (CheSSTaG 769798), EPSRC Established Career Fellowship (EP/N026322/1) and Jeol and DENS Solutions for sponsoring LPR salary, and part of C.D.P. and G.M. studentships. L.R.-A. thanks the UK's ESPRC for funding her salary (Grant EP/N026322/1) and acknowledges support by the Spanish State Research Agency (Spanish Ministry of Science and Innovation) through Juan de la Cierva Incorporacion Fellowship (IJC2018-037951-I). The authors thank Prof. Modesto T. Lopez-Lopez (University of Granada, Spain) for helpful discussions about gel rheology, Dr. Inmaculada Conejos (CIPF, Valencia, Spain) for her help with the CD, and Gabriel Ing (University College London, UK) for his support with transmission electron microscopy.Polypeptide-based nanoparticles offer unique advantages from a nanomedicine perspective such as biocompatibility, biodegradability, and stimuli-responsive properties to (patho)physiological conditions. Conventionally, self-assembled polypeptide nanostructures are prepared by first synthesizing their constituent amphiphilic polypeptides followed by postpolymerization selfassembly. Herein, we describe the one-pot synthesis of oxidation-sensitive supramolecular micelles and vesicles. This was achieved by polymerization-induced self-assembly (PISA) of the N-carboxyanhydride (NCA) precursor of methionine using poly(ethylene oxide) as a stabilizing and hydrophilic block in dimethyl sulfoxide (DMSO). By adjusting the hydrophobic block length and concentration, we obtained a range of morphologies from spherical to wormlike micelles, to vesicles. Remarkably, the secondary structure of polypeptides greatly influenced the final morphology of the assemblies. Surprisingly, wormlike micellar morphologies were obtained for a wide range of methionine block lengths and solid contents, with spherical micelles restricted to very short hydrophobic lengths. Wormlike micelles further assembled into oxidation-sensitive, self-standing gels in the reaction pot. Both vesicles and wormlike micelles obtained using this method demonstrated to degrade under controlled oxidant conditions, which would expand their biomedical applications such as in sustained drug release or as cellular scaffolds in tissue engineering.Royal Society of London European Commission 2017-NF171487EU H2020 MSCA-IF-792957 European Research Council (ERC) European Commission CheSSTaG 769798UK Research & Innovation (UKRI)Engineering & Physical Sciences Research Council (EPSRC) EP/N026322/1Jeol and DENS SolutionsUK's ESPRC EP/N026322/1Spanish State Research Agency (Spanish Ministry of Science and Innovation) IJC2018-037951-

Habilidades directivas y de organización: gestión del tiempo

El presente trabajo trata de la gestión del tiempo como una de las habilidades fundamentales de la dirección para la correcta ejecución de su tarea y de sus fases: Gestionar el tiempo implica en primer lugar decidir qué hay que hacer, es decir, planificar las tareas; en segundo lugar, hay que priorizar las mismas y, en tercer lugar, hay que programarlas y saber en cada momento qué nos corresponde hacer. Para comenzar, en la parte teórica del trabajo se define el tiempo como recurso, así como sus particularidades. A continuación, se analiza la gestión del tiempo vista desde dos perspectivas, por un lado la gestión del tiempo propio del directivo y por otro la gestión del tiempo de los demás. Una vez terminada la parte teórica del trabajo, se analizan tres casos de estudio como una primera aproximación para el mayor conocimiento del comportamiento y las actuaciones de los directivos, lo cual permite proponer diferentes áreas de mejora referentes a la gestión de su tiempo. Las principales áreas que se ponen de manifiesto son: Primero, sus agendas, que no son flexibles y no pueden atender imprevistos cuando surgen. Segundo, la dificultad para delegar satisfactoriamente parte de su trabajo. Tercero, no suelen tratar de una sola vez la documentación que les llega y esto les puede llevar a acumular papeles y no tener claro qué hacer con ellos. Y, cuarto, a veces no son capaces de decir “no” cuando les necesitan para cosas que interfieren con su tiempo destinado a asuntos pendientes

How nonmagnetic particles intensify rotational diffusion in magnetorheological fluids

In this work we propose a mechanism to explain the enhancement of the magnetic field-induced yield stress when non-magnetic particles are added to magnetic particulate suspensions –i.e., bi-component suspensions. Our main hypothesis is that the non-magnetic particles collide with the field-induced magnetic aggregates under shear flow. Consequently, supplementary fluctuations of the orientations of the magnetic aggregates occur, resulting in an effective rotary diffusion process, which increases the dynamic yield stress of the suspension. Furthermore, the collision rate and the rotary diffusivity of the aggregates should increase with the concentration of non-magnetic particles. Rheological measurements in plate-plate and cylindrical Couette geometries confirm the increase of the yield stress with the volume fraction of non-magnetic particles. In addition, such an effect appears to be more important in Couette geometry, for which orientation fluctuations of the magnetic aggregates play a more significant role. Finally, a theoretical model based on this rotary diffusion mechanism is developed, providing with a quantitative explanation to the experimentally-observed trends.This work was supported by Project No. FIS2013-41821-R (Ministerio de Economía y Competitividad, Spain) and the project “Factories of the Future” (Grant No. 260073, DynExpert FP7). In addition, L.R.-A. acknowledges financial support from Secretaría de Estado de Educacion, Formación´ Profesional y Universidades (MECD, Spain) through its FPU and Estancias Breves programs

Mechanical assessment of novel compliant mechanisms for underactuated prosthetic hands

This paper proposes novel compliant mechanisms for constructing hand prostheses based on soft robotics. Two models of prosthetic hands are developed in this work. Three mechanical evaluations are performed to determine the suitability of the two designs for carrying out activities of daily living (ADLs). The first test measures the grip force that the prosthesis can generate on objects. The second determines the energy required and dissipated from the prosthesis to operate. The third test identifies the maximum traction force that the prosthesis can support. The tests showed that the PrHand1 prosthesis has a maximum grip force of 23.38 ± 1.5 N, the required energy is 0.76 ± 0.13 J, and the dissipated energy is 0.21 ± 0.17 J. It supports a traction force of 173.31 ± 5.7 N. The PrHand2 prosthesis has a maximum grip force of 36.13 ± 2.3 N, the required energy is 1.28 ± 0.13 J, the dissipated energy is 0.96 ± 0.12 J, and it supports a traction force of 78.48 ± 0 N. In conclusion, the PrHand1 prosthesis has a better performance in terms of energy and tensile force supported. The difference between the energy and traction force results is related to two design features of the PrHand2: fully silicone-coated fingers and a unifying mechanism that requires more force on the tendons to close the prosthesis. The grip force of the PrHand2 prosthesis was more robust than the PrHand1 due to its silicone coating, which allowed for an improved grip

Fledgling discrimination in the hoopoe, a potential host species of the great spotted cuckoo

Obligate brood parasites lay their eggs in nests of other species, with host parents bearing the cost of raising their offspring. These costs imposed on hosts select for the evolution of host defenses against parasitism at all stages of the reproductive cycle. The most effective defense is egg rejection at early stages of the breeding cycle, with later-stage defenses (nestling and fledgling discrimination) being less common. In this study, we tested whether the hoopoe (Upupa epops), a potential host of the great spotted cuckoo (Clamator glandarius) without egg rejection ability, presents defenses after the egg stage. We experimentally parasitized hoopoe nests with great spotted cuckoo nestlings creating mixed broods (with hoopoe and cuckoo nestlings) and broods with only cuckoo nestlings and measured parental feeding behavior and survival of nestlings and fledglings of both species. Cuckoo fledglings were fed fewer often than hoopoe fledglings in mixed broods, and adults approached more often to feed hoopoe fledglings than cuckoo fledglings. Consequently, the survival of cuckoo fledglings in both mixed and only-cuckoo-broods, was significantly lower than that of hoopoe fledglings. These results suggest that hoopoes would discriminate great spotted cuckoo fledglings, with or without direct comparison with their own fledglings. However, the survival of some cuckoos suggests that hoopoes have not reached highly efficient defenses so, other life history traits hindering parasitism by cuckoos may explain low parasitism rates and low levels of defenses in this speciesUniversidad de Granada/ CBUASpanish Ministry of Science and Innovation, European funds (FEDER) (CGL2007-61940/BOS, CGL2010-19233-C03-03)Junta de Andalucía (P09-RNM- 4557, P18-FR-2215)Spanish Ministry of Science and Innovation (Subprogram PTA-MICINN) (Ref. PTA2010-4298-I

Mitochondrial movement in Aralar/Slc25a12/AGC1 deficient cortical neurons

The elevated energy demands in the brain are fulfilled mainly by glucose catabolism. In highly polarized neurons, about 10–50% of mitochondria are transported along microtubules using mitochondrial-born ATP to locations with high energy requirements. In this report, we have investigated the impact of Aralar deficiency on mitochondrial transport in cultured cortical neurons. Aralar/slc25a12/AGC1 is the neuronal isoform of the aspartate-glutamate mitochondrial carrier, a component of the malate-aspartate shuttle (MAS) which plays an important role in redox balance, which is essential to maintain glycolytic pyruvate supply to neuronal mitochondria. Using live imaging microscopy we observed that the lack of Aralar does not affect the number of moving mitochondria nor the Ca2+-induced stop, the only difference being a 10% increase in mitochondrial velocity in Aralar deficient neurons. Therefore, we evaluated the possible fuels used in each case by studying the relative contribution of oxidative phosphorylation and glycolysis to mitochondrial movement using specific inhibitors. We found that the ATP synthase inhibitor oligomycin caused a smaller inhibition of mitochondrial movement in Aralar-KO than control neurons, whereas the glycolysis inhibitor iodoacetate had similar effects in neurons from both genotypes. In line with these findings, the decrease in cytosolic ATP/ADP ratio caused by oligomycin was more pronounced in control than in Aralar-KO neurons, but no differences were observed with iodoacetate. Oligomycin effect was reverted by aralar re-expression in knock out cultures. As mitochondrial movement is not reduced in Aralar-KO neurons, these results suggest that these neurons may use an additional pathway for mitochondria movement and ATP/ADP ratio maintenanceThis work was supported by grants S2010/BMD-2402, and a grant from Fundación Ramón Areces to JS; SAF2014-56929-R to JS and BP; SAF2017-82560-R to BP and AdA and an institutional grant from Fundación Ramón Areces to the Centro de Biología Molecular Severo Ochoa. LC has been the recipient of a Junta de Ampliación de Estudios Consejo Superior de Investigaciones Científicas and CIBERER postdoctoral contracts. The authors declare no competing financial interest

Reconfiguraciones, complejidades y articulaciones de la alimentación, la sociedad y el territorio

En la reflexión introductoria titulada “Reconfiguraciones, complejidades y articulaciones de la alimentación, la sociedad y el territorio” y que también constituye la presentación al presente dossier “Tramas agroalimentarias: transformaciones y vínculos entre sociedad, alimentación y territorio”, se profundiza sobre el interés de abonar al conocimiento en torno al quehacer agroalimentario, así como a las complejidades, procesos, interacciones y dinámicas que alrededor de este se desenvuelven. Esto, destacando las implicaciones sociales, económicas, ambientales y culturales de los sentidos y practicas alimentarias, las actividades económicas, las comensalidades, y las configuraciones y reconfiguraciones del acto alimenticio mismo. Este apartado de presentación nos introduce no sólo al contenido del dossier, sino que también sintetiza los aportes de las entrevistas realizadas a expertos del tema, la valía de la traducción de un texto de interés temático, así como sobre los diez artículos académicos realizados por las y los autores, provenientes de distintas latitudes, y con miradas desde diferentes disciplinas y marcos metodológicos

Phagocytosis-inspired behaviour in synthetic protocell communities of compartmentalized colloidal objects

The spontaneous assembly of micro-compartmentalized colloidal objects capable of controlled interactions offers a step towards rudimentary forms of collective behaviour in communities of artificial cell-like entities (synthetic protocells). Here we report a primitive form of artificial phagocytosis in a binary community of synthetic protocells in which multiple silica colloidosomes are selectively ingested by self-propelled magnetic Pickering emulsion (MPE) droplets comprising particle-free fatty acid-stabilized apertures. Engulfment of the colloidosomes enables selective delivery and release of water-soluble payloads, and can be coupled to enzyme activity within the MPE droplets. Our results highlight opportunities for the development of new materials based on consortia of colloidal objects, and provide a novel microscale engineering approach to inducing higher-order behaviour in mixed populations of synthetic protocells