134,598 research outputs found

    Desarrollo de papeles biocativos por injerto de mol茅culas espec铆ficas en celulosa

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    Tesis (DCI)--FCEFN-UNC, 2019En la presente tesis se presenta el desarrollo de papeles bioactivos con potencial aplicaci贸n en el envasado activo de alimentos. Para tal fin, se propuso el injerto de eugenol, un compuesto de origen natural con propiedades antimicrobiana, antioxidante y repelente de insectos, en celulosa, utilizando 谩cido policarbox铆lico como agente ligante. Con el objetivo de evaluar la escalabilidad del proceso propuesto, se estudiaron distintas tecnolog铆as de curado, tales como calentamiento por convecci贸n, infrarrojo, microondas y conducci贸n. En todos los casos, se analizaron la influencia de las variables operativas sobre el avance de la reacci贸n y propiedades finales del papel preparado, utilizando un dise帽o de experimentos Doehlert para elegir las experiencias a realizar, y analizando los resultados mediante metodolog铆a de superficie de respuesta y an谩lisis estad铆stico ANOVA. Se pudo comprobar que la reacci贸n de injerto de eugenol en papel comercial se produjo con 茅xito en todas las tecnolog铆as estudiadas. Asimismo, se encontraron las condiciones 贸ptimas de reacci贸n para cada una de las tecnolog铆as, para lo cual se busc贸 un compromiso entre el avance de la reacci贸n y las propiedades finales del material (mec谩nicas y color). A partir de estas condiciones, se prepararon papeles y se realiz贸 una caracterizaci贸n m谩s espec铆fica para su aplicaci贸n como envase de alimentos comparando los papeles modificados con el papel virgen. Se analizaron las propiedades mec谩nicas por ensayo de tracci贸n, rasgado y punzonado y se midi贸 la absorci贸n de agua y la capacidad de degradaci贸n. Por otro lado, las propiedades bioactivas analizadas fueron la actividad antioxidante, antimicrobiana, repelente e insecticida de gorgojos (T. castaneum y R. dominica). Una vez probado que el papel modificado presenta buenas caracter铆sticas f铆sicas y bioactivas para su posible aplicaci贸n en el envasado de alimentos, se realizaron prototipos de envasado para harina, como alimento representativo de alimentos derivados de cereales, susceptibles al ataque de plagas. En este estudio se analiz贸 la migraci贸n de reactivos, propiedades organol茅pticas y conservaci贸n del alimento, arrojando resultados promisorios para la industria de envases de alimentos. Finalmente, se realiz贸 una comparaci贸n de las tecnolog铆as de curado ensayadas, analizando diferentes aspectos como avance de reacci贸n, propiedades finales, apariencia, tiempo de reacci贸n, consumo de energ铆a, entre otros, como as铆 tambi茅n disponibilidad y uso de estas tecnolog铆as a escala industrial, seleccionando la tecnolog铆a de conducci贸n como la m谩s adecuada para una propuesta de escalado industrial.Fil: Muratore, Florencia. Universidad Nacional de C贸rdoba. Facultad de Ciencias Exactas, F铆sicas y Naturales; Argentina.Fil: Muratore, Florencia. Consejo Nacional de Investigaciones Cient铆ficas y T茅cnicas. Instituto de Investigaci贸n y Desarrollo en Ingenier铆a de Procesos y Qu铆mica Aplicada; Argentina

    Does international patent collaboration have an effect on entrepreneurship?

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    .Entrepreneurship is one of the main pillars of growth in any economy. Achieving a high rate of entrepreneurship in a region has become the priority objective of governments and firms. However, in many cases, new firm creation is conditioned by relations or collaboration in innovation with agents from other countries. Previous literature has analyzed the mechanisms that foster entrepreneurship. This paper attempts to shed light on the influence of international patent collaboration (IPC) on entrepreneurial activity at country level taking into account the timing of this relationship. An empirical study is proposed to verify whether IPC leads to greater entrepreneurship and to analyze the gestation period between international patenting actions and firm creation. Using the Generalized Method of Moments, the two hypotheses proposed were tested in a data panel of 30 countries for the period 2005鈥2017. Results show the influence of IPC in promoting entrepreneurship in the same year, but especially in the following year. The study offers implications for entrepreneurs and public agents. IPC affects the integration and interaction of international agents in a country, favors the production of new knowledge, and increases positive externalities in a territory. All this facilitates the creation of new companies with a high innovative component.S

    El problema de la oligarqu铆a en la Pol铆tica de Arist贸teles

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    p. 69-95La oligarqu铆a es una de las seis formas de Estado y de gobierno que estudi贸 Arist贸teles en su Pol铆tica. La realidad social, pol铆tica e hist贸rica mostr贸 que era la forma de organizaci贸n pol铆tica m谩s frecuente. Arist贸teles distingui贸 varios tipos de oligarqu铆as, estudi贸 c贸mo llegan a instaurarse, las causas de su degeneraci贸n y final extinci贸n. Las ideas de Arist贸teles tuvieron una amplia influencia entre los comentaristas de los siglos XIII a XVII, que optaron por considerar el r茅gimen olig谩rquico como una forma de Estado dominada por pocos o por ricos.S

    The Art of Crafting Useful Citizens: Disability, Charity and the State (1870-1970)

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    During the period 1870 to 1970 popular conceptions of disabled children and adults changed significantly, and the practices and policies established to understand, reform and manage the disruptive disabled body evolved accordingly. Beginning in 1870, when the introduction of compulsory schooling provided the impetus for the development of charitable schools for 'crippled' children, this thesis examines key pieces of educational and employment legislation directed towards disabled adults and children, as well as a number of charitable interventions, over a period of a hundred years. It analyses the shifting relationship between disabled people, charity and the state, and the role played by arts and crafts in different educational, therapeutic and occupational contexts, to consider how these worked to extend, or deny, the rights of citizenship to disabled people throughout this period. It analyses practices associated with arts and crafts, as well as a number of case studies which include: Chailey Heritage Craft School for Crippled Children, The National Spastics Society and the Mouth and Foot Painting Artists Association. It uses these to chart the variable charitable, educational, political frameworks which have redefined, or reaffirmed, the expectations established for disabled children and adults, particularly in areas concerned with their education and employment. The study focuses principally upon disabled children to argue that the early institutions established on their behalf situated the 'crippled' child within the productive realm of adulthood through a work-based approach to education which affirmed their responsibility to be active, productive citizens. It demonstrates how this gradually changed through increased state intervention which progressively worked to redefine the boundaries of disabled children's childhoods and establish their dependency upon the state. Key to these developments were the evolving attitudes and values assigned to disabled people, education and work. Whilst the adult cripple of the nineteenth century was understood to be work-shy, weak and physically unproductive, the working contributions of disabled citizens during the Second World War were acknowledged via the passage of The Disabled Persons (Employment) Act (1944) which affirmed their status as workers. Concurrently, educational policy gradually included more significantly impaired children, which meant educational practice, including arts and crafts, necessarily evolved to consider more holistically the individual needs and development of the disabled child. This thesis argues that this established a broader distinction between the disabled adult and the disabled child, and that this is evident in the educational and occupational expectations established for both following the Second World War. Ultimately this thesis demonstrates how and why 'The Art of Crafting Useful Citizens' came to be an enterprise taken up both by charities and the state at different times, and in different ways. It argues that these approaches reflected the cultural anxieties and values of the time, and thus changed in meaning, form and intended recipient. The frameworks, practices and policies established by charities and the state successively worked to reexamine, recategorise and reform the disabled body, which this thesis argues worked to affirm the dependency of the disabled child, whilst simultaneously reasserting the expectations and rights of disabled adults to engage more completely in their own embodied citizenship through work

    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

    Interactive Sonic Environments: Sonic artwork via gameplay experience

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    The purpose of this study is to investigate the use of video-game technology in the design and implementation of interactive sonic centric artworks, the purpose of which is to create and contribute to the discourse and understanding of its effectiveness in electro-acoustic composition highlighting the creative process. Key research questions include: How can the language of electro-acoustic music be placed in a new framework derived from videogame aesthetics and technology? What new creative processes need to be considered when using this medium? Moreover, what aspects of 'play' should be considered when designing the systems? The findings of this study assert that composers and sonic art practitioners need little or no coding knowledge to create exciting applications and the myriad of options available to the composer when using video-game technology is limited only by imagination. Through a cyclic process of planning, building, testing and playing these applications the project revealed advantages and unique sonic opportunities in comparison to other sonic art installations. A portfolio of selected original compositions, both fixed and open are presented by the author to complement this study. The commentary serves to place the work in context with other practitioners in the field and to provide compositional approaches that have been taken

    Balancing the urban stomach: public health, food selling and consumption in London, c. 1558-1640

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    Until recently, public health histories have been predominantly shaped by medical and scientific perspectives, to the neglect of their wider social, economic and political contexts. These medically-minded studies have tended to present broad, sweeping narratives of health policy's explicit successes or failures, often focusing on extraordinary periods of epidemic disease viewed from a national context. This approach is problematic, particularly in studies of public health practice prior to 1800. Before the rise of modern scientific medicine, public health policies were more often influenced by shared social, cultural, economic and religious values which favoured maintaining hierarchy, stability and concern for 'the common good'. These values have frequently been overlooked by modern researchers. This has yielded pessimistic assessments of contemporary sanitation, implying that local authorities did not care about or prioritise the health of populations. Overly medicalised perspectives have further restricted historians' investigation and use of source material, their interpretation of multifaceted and sometimes contested cultural practices such as fasting, and their examination of habitual - and not just extraordinary - health actions. These perspectives have encouraged a focus on reactive - rather than preventative - measures. This thesis contributes to a growing body of research that expands our restrictive understandings of pre-modern public health. It focuses on how public health practices were regulated, monitored and expanded in later Tudor and early Stuart London, with a particular focus on consumption and food-selling. Acknowledging the fundamental public health value of maintaining urban foodways, it investigates how contemporaries sought to manage consumption, food production waste, and vending practices in the early modern City's wards and parishes. It delineates the practical and political distinctions between food and medicine, broadly investigates the activities, reputations of and correlations between London's guild and itinerant food vendors and licensed and irregular medical practitioners, traces the directions in which different kinds of public health policy filtered up or down, and explores how policies were enacted at a national and local level. Finally, it compares and contrasts habitual and extraordinary public health regulations, with a particular focus on how perceptions of and actual food shortages, paired with the omnipresent threat of disease, impacted broader aspects of civic life

    South Yorkshire low carbon energy supply chains: hydrogen sector summary

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    Structural and Attitudinal Barriers to Bicycle Ownership and Cycle-Based Transport in Gauteng, South Africa

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    Policies that aim to facilitate and promote non-motorised transport (NMT), and in particular cycling, have been developed by many high-income countries facing increasingly congested roads and saturated public transport systems. Such policies are also emerging in many low- and middle-income settings where high rates of urbanisation have led to similar problems with motorised transport. The aim of the present study was to better understand the potential structural and attitudinal barriers to cycle-based transport in one such context: South Africa鈥檚 Gauteng Province, the industrial powerhouse of sub-Saharan Africa that has recently made a firm commitment to NMT. The study focussed on demographic and socioeconomic variation in bicycle and car ownership, and related this to: (1) the reported use of motorised and non-motorised transport (both private and public); and (2) perceived 鈥榩roblems鈥 with cycling. The analyses drew on interviews with key respondents from n鈥=鈥27,490 households conducted in 2013 as part of the third Quality of Life survey undertaken by the Gauteng City Regional Observatory. The survey contained items on three outcomes of interest: household vehicle ownership (bicycles and cars); modes of transport used for the 鈥渢rips鈥 most often made; and respondents鈥 鈥渟ingle biggest problem with鈥 cycling鈥. Respondent- and household-level demographic and socioeconomic determinants of these outcomes were examined using descriptive and multivariable statistical analyses, the latter after adjustment for measured potential confounders identified using a theoretical causal path diagram (in the form of a directed acyclic graph). Of the n鈥=鈥26,469 households providing complete data on all of the variables examined in the present study, only n鈥=鈥8722 (32.9%) owned a car and fewer still (n鈥=鈥2244; 8.4%) owned a bicycle. The ownership of these assets was commonest amongst wealthier, economically active households; and those that owned a car had over five times the odds of also owning a bicycle, even after adjustment for potential confounding (OR 5.17; 95% CI 4.58, 5.85). Moreover, of household respondents who reported making 鈥榯rips鈥 during the preceding month (n鈥=鈥18,209), over two-thirds of those whose households owned a car (70.1%) reported private car-based transport for such trips, while only 3.2% of those owning a bicycle reported cycling. Amongst the specific responses given to the item requesting the 鈥渟ingle biggest problem with鈥 cycling鈥 by far the commonest was 鈥淒on鈥檛 know how to cycle鈥 (32.2%), less than half as many citing 鈥淰ehicle accident risk鈥 (15.9%), and fewer still: 鈥淒estination is too far鈥 (13.9%); 鈥淐rime鈥 (10.3%); 鈥淭oo much effort鈥 (9.2%); or 鈥淟ack of good paths鈥 (4.6%). While the first of these reasons was commonest amongst poorer households, concerns about risk and effort were both most common amongst better educated, economically active and wealthier/better serviced households. In contrast, concerns over (cycle) paths were only common amongst those owning bicycles. The low prevalence of household bicycle ownership, and the disproportionate number of households owning bicycles that also owned cars, might explain the very small proportion of the 鈥榯he trips most often made鈥 that involved cycle-based transport (0.3%), and the preferential use of cars amongst households owning both bicycles and cars. Low levels of bicycle ownership might also explain why so many respondents cited 鈥淒on鈥檛 know how鈥 as the 鈥渟ingle biggest problem with鈥 cycling鈥; although risk and effort were also substantial concerns (presumably for many who did, and some who did not, know how to cycle); the lack of suitable cycle lanes being only primarily a concern for those who actually owned bicycles. Structural and attitudinal barriers to cycle-based transport limit the use of cycle-based transport in Gauteng, not only amongst the vast majority of household respondents who lack the means to cycle (and the means to learn how), but also amongst those dissuaded from learning to cycle, purchasing a bicycle and/or using a bicycle they own by: the risks and effort involved; the lack of suitable cycle paths; and/or because they also own a car and prefer to drive than cycle

    Paradoxes in the Management of Timebanks in the UK鈥檚 Voluntary Sector: Discursive Bricolage and its Limits

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    This paper contributes to our understanding of volunteer management by charting some important challenges associated with the governance of one of the UK鈥檚 largest timebanking networks. While timebanking is often treated as a form of volunteering, many timebank advocates are keen to distinguish it sharply from traditional volunteering. We suggest that this tension generates a fundamental 鈥榩erformance paradox鈥 in the management of timebanks in the voluntary sector. We draw on political discourse theory to characterise and evaluate associated challenges, suggesting that, when viewed against a host of context-specific organisational and policy pressures, the progressive potential of timebanking cannot be realised as a distinct community economy without adequate support. Instead of taking up a position alongside more traditional forms of volunteering, timebanking is more likely to be subsumed by them