364 research outputs found
El Sistema electoral a Austràlia : convivència en la complexitat democràtica
L'objectiu d'aquestes pàgines és descriure el desenvolupament del sistema electoral a Austràlia des de la perspectiva que comporta tant la seva complexitat com flexibilitat. Una complexitat a què s'ha acostumat el ciutadà australià fruit de la naturalesa federal del país. En comptes que les modificacions en les regles del joc democràtic facin perillar la credibilitat del poder polític, Austràlia sempre ha conservat una ferma evolució política a partir dels eixos de buscar la millor representació ciutadana. Aquesta diversitat i sofisticació constant no han portat a la ciutadania a una desinhibició de les regles democràtiques, sinó que s'ha combinat amb una participació electoral obligada dels ciutadans que els implica directament amb el seu sistema polític
Evaluations of the morphologic structure and development of the pequi seed (Caryocar Braziliense Camb.) (Caryocaraceae) using images of magnetic resonance tomography.
Accompanied child irregular migrants who arrive to Spain in small boats: experiences and health needs
The European Union is the preferred destination of child irregular migrants arrived from northern Africa, who risk their lives crossing the Mediterranean Sea in small boats. Accompanied Child Irregular Migrants (AChIMs) are exposed to physical and psychological risk. The objective of our study is to describe and understand the experiences and health needs of AChIMs who arrive to Spain in small boats, through the testimony of adults who accompany them on the journey. A qualitative study, based on Gadamer's hermeneutic phenomenology, was performed. After obtaining approval from the Ethics and Research Committee, we conducted in-depth interviews on 32 adults who travelled with AChIMs. Two main themes emerged: (1) The journey a child should never have to take, with the subthemes 'AChIMs as a paradigm of vulnerability' and 'Crossing the sea, playing with death' and (2) Characterising emergency care to AChIMs, with the subthemes 'Prioritising specific care', 'Identifying high-risk situations' and 'The detaining of innocent children'. AChIMs, along with adults, risk their lives in such a dangerous and perilous journey, therefore, finding out about their experiences may contribute to improving the treatment of their specific health needs during the phases of rescue and emergency care
Effects of web-based electrocardiography simulation on strategies and learning styles
Objective: To identify the association between the use of web simulation electrocardiography and the learning approaches, strategies and styles of nursing degree students. Method: A descriptive and correlational design with a one-group pretest– posttest measurement was used. The study sample included 246 students in a Basic and Advanced Cardiac Life Support nursing class of nursing degree. Results: No significant differences between genders were found in any dimension of learning styles and approaches to learning. After the introduction of web simulation electrocardiography, significant differences were found in some item scores of learning styles: theorist (p < 0.040), pragmatic (p < 0.010) and approaches to learning. Conclusion: The use of a web electrocardiogram (ECG) simulation is associated with the development of active and reflexive learning styles, improving motivation and a deep approach in nursing students
AUTOMATED SYSTEM FOR CONTINUOUS MICROALGAE CULTIVATION IN PHOTOBIOREACTORS
The objective of this work was to design a automate system for microalgae cultivation on a continuous modes in laboratory scale and allow its remote monitoring and control. For this, a sensor were developed is able to measure biomass concentration. The concentration sensor used the principle of light scattering, that is, by measuring the turbidity of the culture medium by the use of a set of phototransistor and green led. It presented an mean absolute percentage error of 8.46% during the experiment. A pH, temperature and light sensor were also installed. The control of all the sensors was accomplished by means of an microcontroller. For remote control and monitoring of the controller, a database was designed and implemented on a Raspberry Pi connected to the network. The graphics and data collected are available on an HTML page that allows changes in the control mode of the photobioreactor, for example by changing the dilution rates. The controller was able to operate the photobioreactor in batch mode, as well as to maintain the culture operating in continuous regime. The continuous production of microalgae biomass in a continuous regime showed productivity 74.5% higher than the traditional batch process and 28.2% higher than semicontinuous cultivation
Ribonucleotide Reductase Requires Subunit Switching in Hypoxia to Maintain DNA Replication.
Cells exposed to hypoxia experience replication stress but do not accumulate DNA damage, suggesting sustained DNA replication. Ribonucleotide reductase (RNR) is the only enzyme capable of de novo synthesis of deoxyribonucleotide triphosphates (dNTPs). However, oxygen is an essential cofactor for mammalian RNR (RRM1/RRM2 and RRM1/RRM2B), leading us to question the source of dNTPs in hypoxia. Here, we show that the RRM1/RRM2B enzyme is capable of retaining activity in hypoxia and therefore is favored over RRM1/RRM2 in order to preserve ongoing replication and avoid the accumulation of DNA damage. We found two distinct mechanisms by which RRM2B maintains hypoxic activity and identified responsible residues in RRM2B. The importance of RRM2B in the response to tumor hypoxia is further illustrated by correlation of its expression with a hypoxic signature in patient samples and its roles in tumor growth and radioresistance. Our data provide mechanistic insight into RNR biology, highlighting RRM2B as a hypoxic-specific, anti-cancer therapeutic target
Improvement of the electrochemical behaviour of Zn-electroplated steel using regenerated Cr(III) passivation baths
Conversion coatings based on trivalent chromium are more sensitive to the presence of zinc and iron impurities than the chromate formulations. This fact contributes to a decrease in the quality of passivation and to the generation of a significant amount of hazardous liquid waste. Recently, a new eco-innovative process based on Emulsion Pertraction Technology (EPT) is being implemented at industrial scale for selectively removing Zn and Fe from spent passivation baths in order to enhance the lifetime of the Cr (III) baths. In this study, the effect of Zn and Fe removal on the electrochemical behaviour of Zn-electroplated steel samples was evaluated by means of polarisation curves and electrochemical impedance spectroscopy measurements at open circuit potential conditions in 3.5 g/L NaCl solutions. The main objective was to assess the benefits brought by EPT using electrochemical methods. Cr (III) passivation baths regenerated using the EPT process have been compared to the bath used in a local industry as well as to fresh and spent baths. According to the results, the samples passivated in the EPT regenerated bath showed a significant improvement in their electrochemical behaviour compared to the samples passivated in the spent baths. This study concluded the suitability of EPT for regenerating Cr (III) passivation baths
Understanding violence against women irregular migrants who arrive in Spain in small boats
African irregular migrants risk their lives crossing the Mediterranean Sea in small boats hoping to reach Europe. Women irregular migrants (WIMs) are an especially vulnerable group that suffer from violence and sexual aggression, but little is known about their actual experiences. The objective of our study is to describe and understand the violence against WIMs who arrive in Spain in small boats. A qualitative study based on Gadamer’s phenomenology was used. The data collection included twenty-six in-depth interviews with WIMs. Three main themes arose: “Poverty and discrimination push WIMs into migrating”; “WIMs as a paradigm of extreme vulnerability”, and “WIMs in small boats should raise the alarm”. WIMs who arrive to Europe in small boats have a history of violence, rape, prostitution, forced pregnancy, and human trafficking. Emergency care must include gynecological examinations and must make detecting sexual violence and human trafficking of WIMs part of their care protocols
Estudio de la interacción péptido-membrana utilizando simulaciones por Dinámica Molecular
Los péptidos antimicrobianos (PAMs) juegan un rol fundamental en el sistema de defensa de todos los organismos. En los eucariotas forman parte de su sistema inmune innato pero además pueden actuar modulando la respuesta inmune adquirida. Se trata de moléculas pequeñas, catiónicos y de naturaleza anfipática. Actúan mediante interacción con la membrana bacteriana: pueden adsorberse, insertarse o translocarse, produciendo la lisis o la permeabilización, formando poros o bien interaccionanando con proteínas de membrana. Además, algunos pueden autoensamblarse en estructuras oligoméricas u otros agregados. Estos mecanismos están relacionados con la estructura 3D y secuencia aminoacídica y, a menudo, implican estructuras transientes que son difíciles de estudiar experimentalmente. Esto impide el desarrollo de PAMs con alto valor terapéutico, lo cual requiere una comprensión detallada del mecanismo de acción Las simulaciones de dinámica molecular (DM) son una herramienta poderosa para comprender estos sistemas y sus procesos dinámicos. En este trabajo llevamos a cabo simulaciones de DM para somuncurin-1, un PAM aislado de la piel de la rana patagónica Pleurodema somuncurense, el cual mostró actividad moderada contra cepas de Escherichia coli y Staphylococcus aureus. Utilizamos dos tipos de bicapas lipídicas: mezclas POPC y POPG/POPE que imitan las membranas de mamíferos y bacterias, respectivamente, y nos centramos en los efectos cooperativos en la interacción de péptidos con bicapas lipídicas. Para obtener un buen muestreo distribuimos péptidos (alta concentración) en el núcleo hidrofóbico de interfase de agua. Las simulaciones se llevaron a cabo utilizando el conjunto NPT a tres temperaturas diferentes, 303K, 310K y 320K, para replicar el sistema al mismo tiempo que se aceleran algunos procesos. Somuncurin-1 mostró mayor afinidad por la interfase lipídica del modelo bacteriano. Además, fue posible acceder al mecanismo de estabilización peptídico en el núcleo hidrofóbico y un análisis posterior mostró las interacciones específicas responsables de esta localización. Si bien estos resultados nos permiten conocer el comportamiento de somuncurin-1 en un entorno de membranas, es necesario continuar con el análisis de las simulaciones para poder inferir cuál es su mecanismo de acción.Fil: Cancelarich, Natalia Lorena. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico. Instituto Patagónico para el Estudio de los Ecosistemas Continentales; ArgentinaFil: Pickholz, Mónica Andrea. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Física; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Física de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Física de Buenos Aires; ArgentinaFil: Domene, C.. University of Bath; Reino UnidoFil: Marani, Mariela Mirta. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico. Instituto Patagónico para el Estudio de los Ecosistemas Continentales; Argentina9na Jornada de Becarios y 1er Encuentro Patagónico de BecariosPuerto MadrynArgentinaCentro Nacional PatagónicoUniversidad Nacional de la PatagoniaInstituto Nacional de Tecnología AgropecuariaConsejo Federal de InversionesUniversidad Tecnológica Naciona
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