6,330 research outputs found

    Identification of Hindbrain Neural Substrates for Motor Initiation in the hatchling Xenopus laevis Tadpole

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    Animal survival profoundly depends on the ability to detect stimuli in the environment, process them and respond accordingly. In this respect, motor responses to a sensory stimulation evolved into a variety of coordinated movements, which involve the control of brain centres over spinal locomotor circuits. The hatchling Xenopus tadpole, even in its embryonic stage, is able to detect external sensory information and to swim away if the stimulus is considered noxious. To do so, the tadpole relies on well-known ascending sensory pathway, which carries the sensory information to the brain. When the stimulus is strong enough, descending interneurons are activated, leading to the excitation of spinal CPG neurons, which causes the undulatory movement of swimming. However, the activation of descending interneurons that marks the initiation of motor response appears after a long delay from the sensory stimulation. Furthermore, the long-latency response is variable in time, as observed in the slow-summating excitation measured in descending interneurons. These two features, i.e. long-latency and variability, cannot be explained by the firing time and pattern of the ascending sensory pathway of the Xenopus tadpole. Therefore, a novel neuronal population has been proposed to lie in the hindbrain of the tadpole, and being able to 'hold' the sensory information, thus accounting for the long and variable delay of swim initiation. In this work, the role of the hindbrain in the maintenance of the long and variable response to trunk skin stimulation is investigated in the Xenopustadpole at developmental stage 37/38. A multifaceted approach has been used to unravel the neuronal mechanisms underlying the delayed motor response, including behavioural experiments, electrophysiology analysis of fictive swimming, hindbrain extracellular recordings and imaging experiments. Two novel neuronal populations have been identified in the tadpole's hindbrain, which exhibit activation patterns compatible with the role of delaying the excitation of the spinal locomotor circuit. Future work on cellular properties and synaptic connections of these newly discovered populations might shed light on the mechanism of descending control active at embryonic stage. Identifying supraspinal neuronal populations in an embryonic organism could aid in understanding mechanisms of descending motor control in more complex vertebrates

    Power in the health service : The effects of reorganisation on professions and bureaucracies

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    The National Health Service (NHS) has been analysed predominantly in terms dictated by a systems/functional model of organisational behaviour. Decision-making processes which did not comply with this model were regarded as pathological or dysfunctional. This study takes a different stance and looks at District Health Authorities (DHAs) to see if the NHS can be better understood by accepting Lukes' conception of a "third dimension of power". The study is not focussed around conflicts of interest because the third dimension of power involves situations in which "real" interests may remain unknown. Power may prevent conflicts becoming apparent and interests becoming realised. Because, however, Lukes had suggested that interests may become realised during periods of change, the study focusses on the restructuring which began with reorganisation of the NHS in 1982. The parts played by medical professionals, administrative staff, nursing staff, and lay-members on DHAs are examined and demonstrate the extent to which their activities were influenced by one another and by their external political environment, notably the Conservative government. The mechanisms of power used during the period 1982-1985 when new management structures were established and then replaced by a further reorganisation of management are examined. This shows the extent to which these new management changes became accepted as legitimate and how the legitimation process began with the 1982 reorganisation. Lukes' third dimension of power is confirmed as too restrictive a conception and that power is more subtle than even he had proposed. Nor is it always repressive or manipulative

    Making Sense of Ayahuasca Non-Sense: A critical study of UK groups consuming a psychoactive plant mixture and their struggle to find religious meaning

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    How we make sense of ourselves, and the cosmos is an ongoing concern, guided by the people we meet, environments we exist within, and plants we consume. Having spent over a year observing forty-nine participants within three UK-based ayahuasca churches, it is clear that the psychoactive 'brew' ayahuasca creates intense changes to how individuals think about themselves and the world they live in. At the heart of the ayahuasca experience are non-sensical hallucinations and visions, which often exist outside of perceptual understanding, leaving individuals feeling lost in an unknowable universe. As we will come to see, making sense of non-sensical ayahuasca experiences requires individuals to negotiate multiple 'common-sense' views of reality. Taking a view that mind is something that happens within life, this ethnographic study uses participant observation, interviews, conversations, personal diaries, and my experiences as an ayahuasca tourist to detail how making sense of reality is also an act of making oneself. In so doing, I argue that ayahuasca hallucinations and visions function as a source of ongoing mental innovation, facilitating preferred views of reality throughout these psychoactive churches. Critically, we will see how frequent ayahuasca consumption engenders in-depth beliefs in the supernatural, and in particular, devotion to the goddess Ayahuasca, who functions as the unchallengeable road to knowing oneself and reality. Acting as an otherworldly guide, the immaterial goddess Ayahuasca plays a key part in how individuals convert non-sensical experiences into sense, while providing practical advice for how to achieve salvation. Problematically though, positioning the universe and oneself as predominantly supernatural tends to erode beliefs in the physical world, leaving these churches with incoherent views of reality, and at the periphery of everyday social life. As such, church doctrines seem increasingly unable to cope with life outside of their groups, and thus, tactically stigmatise competing views of reality as sinful and individuals espousing such heresies as under the control of malevolent demonic beings. Not surprisingly, this binary belief in a good and evil cosmos is a powerful regulatory force dictating what reality is within these churches, and who church members can claim to be

    FORTHEM Alliance Universities’ Selected Good Practices in R&I. Towards a European University

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    Libro sobre buenas prácticas en universidades FORTHEM en 5 áreas clave: internacionalización, ciencia abierta, co-creación con el ecosistema social y empresarial, y comunicación de la ciencia.This project has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No 101017248.Book on existing good practices developed in FORTHEM universities regarding the key research areas identified - on the topics: internationalisation, open science, co-creation with the social and business ecosystem, and communication of scienc

    AplicaciĂł de nous materials i formats amb propietats millorades per a l'anĂ lisi de drogues

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    Aquesta Tesi Doctoral està dividida en tres blocs principalment. El primer bloc, a partir d’una recerca bibliogràfica, fa un recull de les publicacions més destacades que fan ús de materials intel·ligents per al tractament de mostra abans d’una determinació mitjançant IMS. Tanmateix, a aquest bloc es recullen les aportacions més interessants dels materials intel·ligents a l’anàlisi forense en general. Entre les quals és especialment destacable l’anàlisi de drogues pel que ocupa els pròxims capítols de la Tesi. El segon bloc, recull les publicacions originals derivades de la recerca portada a terme per a aquesta Tesi Doctoral. Aquests treballs tracten sobre la preparació i aplicació de nous materials i formats de caràcter genèric per a l’extracció de drogues de mostres de saliva i la seua posterior determinació mitjançant tècniques cromatogràfiques o afins tals com l’espectrometria de mobilitat iònica (IMS), la cromatografia de gasos acoblada a espectrometria de masses (GC-MS) o la cromatografia líquida acoblada a espectrometria de masses en tàndem (UHPLC-MS/MS). D’aquesta manera, a aquest bloc es porta a terme la determinació de noves substàncies psicoactives (NPS) tals com dicloropà, metilona o diversos cannabinoides sintètics en mostres de saliva mitjançant l’extracció amb adsorbent empaquetat (MEPS). També es van preparar puntes de micropipeta farcides amb un monòlit basat en àcid metacrílic i etilenglicol dimetacrilat, poly (MAA-co-EGDMA), amb propietats de materials de tipus mixt, per a la determinació de diverses drogues de caràcter bàsic en mostres de saliva. Amb l’objectiu d’obtindre materials més versàtils, també s’hi va preparar un polímer amb propietats de bescanvi iònic de doble acció (bescanvi aniònic i catiònic) així com amb l’habilitat de retenir compostos mitjançant interaccions hidrofòbiques. D’aquesta manera es va preparar un polímer basat en 4-vinilpiridina, àcid metacrílic i etilenglicol dimetacrilat, poly (VP-co-MAA-co-EGDMA). Al tercer bloc, s’enfoca l’anàlisi de drogues des de un punt de vista més selectiu. Per aquest motiu, principalment es mostra l’aplicació de materials com els polímers de reconeixement molecular (MIPs) en formats tals com l’extracció en fase sòlida convencional (SPE) així com en nous formats per a l’extracció de diverses drogues de manera selectiva. En aquest sentit, en primer lloc es va preparar un MIP emprant cocaïna com a molècula plantilla per a la l’extracció de la mateixa mitjançant SPE i la seua posterior anàlisi per IMS. Seguint amb el format SPE, es va preparar un MIP emprant metamfetamina com a molècula plantilla que havia estat prèviament preparat per altres grups. L’objectiu d’aquest estudi va ser portar a terme una caracterització rigorosa del MIP i avaluar la seua selectivitat creuada front a un gran nombre de substàncies il·lícites, principalment NPS de tipus amfetamina com derivats de la mateixa o catinones sintètiques entre altres. Atenent als avantatges proporcionats per la selectivitat creuada que va mostrar el MIP preparat en presència de metamfetamina, posteriorment es va preparar un MIP emprant un derivat de la fenciclidina (3-OH PCP) com a molècula plantilla. Aquest MIP va ser caracteritzat i aplicat posteriorment per a l’anàlisi d’aquesta en mostres de fluids orals. Però també es va desenvolupar un estudi sobre com la modificació de l’etapa de rentat durant l’extracció por afavorir l’obtenció de mètodes específics per a la determinació només de 3-OH PCP o cap a l’obtenció de mètodes, també selectius, però que permeteren una determinació d’altres compostos estructuralment semblants. Altre objectiu plantejat pel que respecta a l’aplicació de materials selectius està basat en l’obtenció de nous formats per a l’extracció de drogues. En aquest sentit, seleccionant la cocaïna com a substància a determinar per la seua rellevància social, es van desenvolupar diversos mètodes d’extracció emprant MIPs en diversos formats. El primer dels treballs que es mostra en aquest sentit desenvolupa un dispositiu per a la determinació ràpida i in-situ de cocaïna en mostres de saliva mitjançant IMS. A partir de la incorporació d’una primera part que permeta el mostreig junt a una segona part capaç de retenir selectivament la cocaïna i separar-la de la resta de components de la matriu, es va obtindre un dispositiu capaç de portar a terme una determinació semi-quantitativa de cocaïna. Tanmateix, en vista d’algunes de les limitacions que planteja la SPE tradicional, el MIP preparat prèviament per a la determinació de cocaïna va ser ancorat sobre nanopartícules magnètiques amb la finalitat de realitzar una SPE dispersiva, evitant les etapes típiques de separació de l’adsorbent (filtració o centrigufació) i canviant-les per una ràpida separació mitjançant l’aplicació d’un camp magnètic. Altre dels enfocaments que es deriven de l’aplicació dels MIPs a nous formats està basat en la preparació d’un MIP en forma monolítica ancorat sobre la superfície d’un disc de tefló adequadament modificat per tal crear un disc d’agitació-extracció que permeta l’extracció d’ecgonina metil èster, un dels principals metabòlits de la cocaïna, que va ser emprada com a molècula plantilla per la síntesi del MIP esmentat en mostres d’aigües naturals i de depuradora. Pel que respecta a l’aplicació de nous materials selectius per a l’anàlisi de drogues en diverses matrius, també es planteja l’aplicació d’aptàmers per a la preparació d’oligosorbents per a l’anàlisi selectiva de diversos anàlits incloent fluoroquinolones i metamfetamina (Capítol 14). En aquest sentit, a la present Tesi Doctoral es mostren resultats preliminars sobre la preparació d’aquests oligosorbents sobre safarosa activada amb bromur de cianogen així com sobre partícules magnètiques per a l’extracció en SPE o SPE dispersiva magnètica. En conclusió, al llarg d’aquesta Tesi Doctoral, diferents materials selectius i no selectius, han estat preparats per tal de portar a terme el tractament de mostra de saliva i aigües naturals i residuals per a la determinació de drogues. Els estudis portats a terme han demostrat que la IMS és una tècnica analítica ràpida amb la capacitat de detectar de manera satisfactòria drogues després d’un tractament de mostra adequat emprant MIPs. A més, els materials no selectius com la sílice modificada amb C18 o els materials de tipus mixt, han estat emprats per extraure nombroses drogues amb bons resultats sempre i quant la tècnica analítica seleccionada tinga suficient selectivitat i sensibilitat com GC-MS o UHPLC-MS/MS.This PhD thesis is entitled “New materials and approaches with improved properties for drug analysis (Aplicació de nous materials i formats amb propietats millorades per a l’anàlisi de drogues)”. It is divided in three main sections. The first one does a collection of the most remarkable published papers about the use of smart materials for sample treatment prior an IMS detection. Likewise, this section collects the most interesting contribution of smart materials to forensic analysis in general. It is especially important in this section drug analysis because of the guidelines on which this PhD thesis has been written. The second section collects original publications from the research done along this PhD Thesis. These studies are focused on the preparation and application of new materials and approaches with non-specific interactions for drug extraction from oral fluid samples and its subsequent determination by chromatographic techniques such as gas chromatography coupled to mass spectrometry (GC-MS), liquid chromatography couples to mass spectrometry in tandem (UHPLC-MS/MS) or ion mobility spectrometry (IMS). In this wat, the second section shows the development of methods based on microextraction by packed sorbent (MEPS) for the determination of new psychoactive substances (NPS) such as dichloropane, methylone or several synthetic cannabinoids. In this section, it is also shown the preparation of pipette tips filled with a polymeric monolith based on methacrylic acid and ethylene glycol dimethacrylate, poly (MAA-co-EGDMA). These polymers showed mixed-mode properties. It was able to retain satisfactorily several basic drugs from oral fluid samples. In order to obtain versatile materials, another polymeric material with double action ion exchange properties was prepared by the incorporation of 4-vinylpyridine and methacrylic acid to an ethylene glycol dimethacrylate backbone. Poly (VP-co-MAA-co-EGDMA) was able to create anion and cation exchange depending on the pH used, and it also revealed the ability to create hydrophobic interactions. The third section is focused on drug analysis by a selective approach. For this reason, it shows the application of materials such as molecularly imprinted polymers (MIPs) in different approaches such as conventional solid phase extraction (SPE) and new approaches. In this sense, firstly, a cocaine based-MIP was prepared for cocaine extraction form oral fluid and its subsequent determination by IMS. A second MIP, that was prepared previously by other groups, was prepared using methamphetamine as template molecule. The main aim of this study was to do a deep characterization of the MIP and evaluate its cross-selectivity against different illicit substances. The substances under study were amphetamine-type NPS including amphetamine derivatives and synthetic cathinone. Regarding the benefits of the cross-selectivity of some MIP, in this Thesis was prepared a MIP using 3-hydroxi phencyclidine (3-OH PCP) as template. This MIP was characterized and applied for the analysis of oral fluid samples. Besides, 3-OH PCP based-MIP was submitted to a study about tuning the selectivity. It was demonstrated that according to the washing step it was possible to obtain a specific method for 3-OH PCP extraction or a selective method with the ability to extract different structural related compounds. Another scope proposed on this Thesis was the development of new approaches of solid extraction based on selective materials. In this sense, cocaine was selected as target analyte due to its high social importance. Different approaches were developed using MIPs as selective materials. The first one was based on a device for fast and in-situ determination of cocaine using IMS. The device was composed by a first part that integrates a sample collector and a second part which contains the MIP to adsorb selectively cocaine, removing the other components of the matrix. Likewise, some limitations of conventional SPE were fixed by the use of magnetic dispersive solid phase extraction (MDSPE). The prepared MIP was incorporated covalently to magnetic nanoparticles. This magnetic MIP was able to perform a dispersive extraction avoiding the typical filtration/centrifugation steps of dispersive extraction to separate the sorbent. Thus, an easy separation by the application of a simple magnetic field was done. Another approach studied in this Thesis was based on the preparation of a monolithic polymer anchored onto a disk to create an agitation-extraction device. The MIP was prepared using ecgonine methyl ester, one of the main metabolites of cocaine, and it was applied for natural and wastewater analysis. Finally, it was also proposed the development of new materials based on aptamers for drug extraction. Different oligosorbents were prepared by aptamers immobilization onto CNBr-activated sepharose and magnetic beads for fluroroquinolones and methamphetamine determination. Thus, in the last chapter of this PhD Thesis, the preliminary results of SPE and MDSPE using oligosorbents for drug extraction are shown. In conclusion, along this PhD Thesis different materials including selective and non-selective have been prepared in order to perform the clean-up of oral fluid and water samples for drug analysis. The studies developed have demonstrated that IMS is a fast analytical technique with the ability to detect satisfactorily drugs after a selective extraction using MIPs. Besides, non-selective materials such as polymeric mixed-mode sorbents or octadecyl silica can be used to extract numerous drugs if the analytical technique used for determination have enough selectivity and sensitivity such as GC-MS or UHPLC-MS/MS

    Interfacial Engineering in Vacuum-Deposited Perovskite Solar Cells for Improved Performance and Space Stability

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    Perovskite solar cells are an emerging technology that is evolving rapidly, with power conversion efficiency values that compete with traditional materials such as silicon. In this type of solar cells the photons are absorbed in the perovskite and the charges are extracted using transport materials. By sandwiching the perovskite between a material with and excess of negative (N) or positive (P) charge, one can fabricate a P-i-N or N-i-P structure depending on the deposition order of the materials. Perovskite solar cells have several advantages, mainly the possibility of being very thin thanks to the high absorption coefficient of the perovskite and the wide range of deposition techniques, compatible with industry. From all the deposition techniques, vacuum sublimation stands out due to several advantageous characteristics. This method consists in subliming in high vacuum the required precursor materials for a certain composition, depositing the resulting perovskite onto a substrate. Sublimed perovskite solar cells generally rely on doped organic layers for transporting the electrons and holes photogenerated, which might be chemically unstable and absorb some part of the light, reducing the current generated. This thesis aims to improve vacuum deposited perovskite solar cells, enhancing the stability and performance of the devices. To fulfill this objective, we explore the substitution of the weakest part of the device, the doped transport layers, by implementing the use of transition metal oxides. This type of metal oxides stands out due to the wide range of work functions available and their self-doping, which improves the charge transport thanks to their natural crystal defects. The most interesting metal oxides for the N side are TiO2 and SnO2 due to their adequate energy levels and their proper charge transport. For the P side we chose MoO3 thanks to the possibility of being sublimed and its good hole injection behavior. For these reasons, the thesis is structured as follows: -Chapter 3: Substitution of doped C60 in N-i-P vacuum deposited perovskite solar cells by a TiO2 nanoparticle dispersion, leading to devices with higher efficiencies and better reproducibility. -Chapter 4: Substitution of doped TaTm in P-i-N vacuum deposited perovskite solar cells by MoO3 and then the implementation of this layer in the N-i-P configuration, leading to a design with metal oxides on both contacts. -Chapter 5: Characterization of the P-i-N architecture with MoO3 from chapter 4 under space conditions, which was proven to be very stable and opened the possibility of using perovskite solar cells in high altitude conditions. The substitution of the doped transport layers led to devices with higher power conversion efficiencies (more than 20%, among the highest values for vacuum deposited CH3NH3PbI3 solar cells to date) and more robustness, passing stability tests under space conditions. The work developed in this thesis has opened an interesting field for vacuum deposited perovskite solar cells and changed the main fabrication routes in our laboratoryPerovskite solar cells are an emerging technology that is evolving rapidly, with power conversion efficiency values that compete with traditional materials such as silicon. In this type of solar cells the photons are absorbed in the perovskite and the charges are extracted using transport materials. By sandwiching the perovskite between a material with and excess of negative (N) or positive (P) charge, one can fabricate a P-i-N or N-i-P structure depending on the deposition order of the materials. Perovskite solar cells have several advantages, mainly the possibility of being very thin thanks to the high absorption coefficient of the perovskite and the wide range of deposition techniques, compatible with industry. From all the deposition techniques, vacuum sublimation stands out due to several advantageous characteristics. This method consists in subliming in high vacuum the required precursor materials for a certain composition, depositing the resulting perovskite onto a substrate. Sublimed perovskite solar cells generally rely on doped organic layers for transporting the electrons and holes photogenerated, which might be chemically unstable and absorb some part of the light, reducing the current generated. This thesis aims to improve vacuum deposited perovskite solar cells, enhancing the stability and performance of the devices. To fulfill this objective, we explore the substitution of the weakest part of the device, the doped transport layers, by implementing the use of transition metal oxides. This type of metal oxides stands out due to the wide range of work functions available and their self-doping, which improves the charge transport thanks to their natural crystal defects. The most interesting metal oxides for the N side are TiO2 and SnO2 due to their adequate energy levels and their proper charge transport. For the P side we chose MoO3 thanks to the possibility of being sublimed and its good hole injection behavior. For these reasons, the thesis is structured as follows: -Chapter 3: Substitution of doped C60 in N-i-P vacuum deposited perovskite solar cells by a TiO2 nanoparticle dispersion, leading to devices with higher efficiencies and better reproducibility. -Chapter 4: Substitution of doped TaTm in P-i-N vacuum deposited perovskite solar cells by MoO3 and then the implementation of this layer in the N-i-P configuration, leading to a design with metal oxides on both contacts. -Chapter 5: Characterization of the P-i-N architecture with MoO3 from chapter 4 under space conditions, which was proven to be very stable and opened the possibility of using perovskite solar cells in high altitude conditions. The substitution of the doped transport layers led to devices with higher power conversion efficiencies (more than 20%, among the highest values for vacuum deposited CH3NH3PbI3 solar cells to date) and more robustness, passing stability tests under space conditions. The work developed in this thesis has opened an interesting field for vacuum deposited perovskite solar cells and changed the main fabrication routes in our laborator

    Practices of shared living: Exploring environmental sustainability in UK cohousing, community living, and coliving

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    The environmental impacts of the UK’s domestic sector must be lowered if they are to meet UK government greenhouse gas emissions (GHGs) reduction targets. However, government initiatives to lower domestic GHGs have had little success, and progress has been too slow. Given this lack of top-down impetus, it is worth investigating alternative housing solutions. Previous research has shown that shared living – in which residents share spaces, resources, and social time – tends to have lower environmental impacts than the average household. However, this issue has not yet been explored within the UK. There is also research which shows that social networks can be effective in encouraging practice transitions and maintenance. This has not yet been thoroughly investigated within the context of shared living and environmental sustainability. This research aimed to explore the practices and infrastructures which enable pro-environmental outcomes within shared living. This aim was achieved through in-depth research in six shared living case studies. The research mainly adopted an ethnographic approach, complemented by quantitative measurement of GHGs. This research shows that the shared living case studies have significantly lower GHGs than the average UK household. This builds upon previous quantitative environmental evaluations of shared living. In studying practices, infrastructures and social networks within shared living, this research identifies four types of sharing that are significant to pro-environmental outcomes: shared ideals, shared governance, shared materials and spaces, and shared endeavour. For each type of sharing, the findings describe and analyse how processes of negotiation enable and constrain pro-environmental practices and outcomes. By exploring these processes, this research generates new knowledge on how and why shared living can produce lower-than-average domestic environmental impacts. Thus, the research demonstrates the potential and the mechanisms by which shared living may offer environmentally sustainable housing solutions for the UK

    In pursuit of eco-innovation

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    This study makes theoretical and methodological contributions to the field of eco-innovation research. The first theoretical contribution pertains to the literature review, which offers a synthesis regarding eco-innovation definitions, the main dimensions of eco-innovation, eco-innovation features, eco-innovation drivers and eco-innovation outcomes. This is followed by a proposal of our own definition of eco-innovation, developed based on the results and findings of this study
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