502 research outputs found

    Microbiota development and mucosal IgA responses during childhood in health and allergic disease

    Full text link
    Tesis por compendio[ES] Antecedentes: Los patrones de colonización microbiana alterados durante la infancia pueden ser en parte responsables del aumento de enfermedades alérgicas en los países desarrollados. La microbiota intestinal difiere en composición y diversidad durante los primeros meses de vida en niños que luego desarrollan o no una enfermedad alérgica. Sin embargo, poco se sabe sobre la importancia de las respuestas inmunitarias tempranas de la mucosa a la microbiota intestinal en el desarrollo de alergias infantiles. Además, los estudios con respecto al efecto protector de la microbiota de la leche materna en el riesgo de desarrollar alergias no han sido concluyentes. Aunque la cavidad bucal es el primer lugar de encuentro entre la mayoría de los antígenos exógenos y el sistema inmunológico, no existen datos sobre la influencia de las bacterias orales en el desarrollo de alergias durante la infancia. Objetivos: El objetivo general de esta tesis fue evaluar la composición y diversidad microbiana en muestras orales, intestinales y de leche materna, junto con su interacción con IgA, para estudiar el papel de la colonización microbiana durante edades tempranas de la vida en condiciones de salud y de enfermedad alérgica. Sujetos: Los bebés y las madres incluidas en este estudio forman parte del ensayo aleatorio doble ciego más grande de Suecia, entre 2001 y 2003, donde se evaluaron los posibles efectos preventivos sobre la alergia de Lactobacillus reuteri ATCC 55730 hasta los 2 y 7 años. En esta tesis, utilizamos muestras de heces recogidas a los 1 y 12 meses, y muestras orales de bebés, obtenidas longitudinalmente a los 3, 6, 12, 24 meses y 7 años. Además, analizamos muestras de leche materna, recogidas a un mes después del parto de las madres correspondientes. Métodos: Se utilizaron tecnologías de secuenciación de segunda generación dirigidas al gen 16S rARN, en combinación con citometría de células marcadas por fluorescencia, para abordar las respuestas de IgA de la mucosa hacia las bacterias intestinales y de la leche materna. Además, se utilizó la secuenciación del gen 16S para describir la colonización oral de la microbiota, en muestras de saliva, de niños que desarrollaron alergias o de aquellos que se mantuvieron sanos. Los niveles de carga bacteriana en diferentes hábitats microbianos se obtuvieron mediante la metodología de qPCR y los niveles totales de IgA de las muestras de heces se determinaron mediante inmuno-ensayo ELISA. Resultados y conclusión: La colonización de la cavidad bucal durante la infancia temprana es progresiva, aumenta en complejidad con el tiempo, y varios factores externos parecen influir en gran medida en la maduración de la microbiota oral, ya sea con un impacto a corto o largo plazo. Los cambios tempranos en la composición microbiana oral parecen influir en la maduración inmune y el desarrollo de alergias en la infancia, y la presencia de especies bacterianas específicas puede ser importante para este proceso. Además, las respuestas de IgA alteradas hacia la microbiota intestinal durante la infancia precedieron a las manifestaciones de asma y alergia durante los primeros 7 años de vida, y el consumo de leche materna con una riqueza microbiana reducida en el primer mes de vida puede aumentar el riesgo de desarrollar alergia durante la infancia. Los hallazgos observados en la presente tesis deben confirmarse en cohortes más grandes y la importancia de los factores ambientales postnatales para el desarrollo temprano de la microbiota debe abordarse más a fondo. Las investigaciones futuras deben ir más allá de la caracterización de la composición de la comunidad bacteriana e investigar los mecanismos funcionales entre los microorganismos colonizadores tempranos, la maduración inmunitaria y la alergia, así como el desarrollo del asma durante la infancia.[CA] Antecedents: S'ha proposat que els patrons de colonització microbiana alterats durant la infància podrien ser en part els responsables de l'augment de malalties al·lèrgiques als països desenvolupats. La microbiota intestinal difereix en composició i diversitat durant els primers mesos de vida en els nens que després van desenvolupar una malaltia al·lèrgica. No obstant això, poc es sap sobre la importància de les respostes immunes de la mucosa a la microbiota intestinal en el desenvolupament d'al·lèrgies infantils. A més, les investigacions amb relació a l'efecte protector de la microbiota de la llet materna en el risc de desenvolupar al·lèrgies no han sigut concloents. Encara que la cavitat bucal és el primer lloc de trobada entre la majoria dels gèneres externs i el sistema immunològic, encara no s'ha descobert la influència dels bacteris en el desenvolupament d'una al·lèrgia durant la infància. Objectius: L'objectiu general d'aquesta tesi va ser avaluar la composició microbiana i la diversitat de mostres orals, fecals i llet materns, juntament amb la seva interacció amb IgA, per estudiar el paper del desenvolupament microbià durant el període de la infància primerenca a la salut i la malaltia al·lèrgica. Subjectes: Les mares i xiquets inclosos en aquest estudi formen part d'un estudi aleatori doble-cec a Suècia, entre el 2001 i el 2003, on es van avaluar els possibles efectes preventius de la suplementació amb Lactobacillus ATCC 55730 fins als 2 i 7 anys. En aquesta tesi, s'utilitzaren mostres de bebès arreplegades longitudinalment, obtinguts a 1 i 12 mesos, 3, 6, 12, 24 mesos i 7 anys, respectivament. A més, s'analitzaren les mostres de llet materna, arreplegades a un mes postpart de les corresponents mares. Mètodes: S'han utilitzat tecnologies de seqüenciació de nova generació dirigides al ARNr 16S, en combinació amb la classificació de les cèl·lules activades, per abordar les respostes de la mucosa cap als bacteris intestinals i de la llet materna. A més, s'utilitzà la seqüenciació d'Illumina MiSeq del gen 16S per descriure la colonització microbiana oral, i es van obtenir mostres longitudinals de saliva de menuts que varen desenvolupar al·lèrgies i d'alguns que es van mantenir saludables. Els nivells de càrrega bacteriana en diferents nínxols microbians s'han obtingut mitjançant la metodologia de qPCR i els nivells totals d'IgA de les mostres fecals es determinaren mitjançant l'immunoassaig ELISA. Resultats i conclusions: La colonització de la cavitat bucal durant la primera infància és transitòria, augmenta la seva complexitat amb el temps, i diversos factors externs influeixen en gran mesura el procés de maduració de la microbiota oral, amb un impacte a curt i llarg termini. Els canvis primerencs en la composició microbiana oral pareixen influir en la maduració del sistema immunològic i el desenvolupament d'al·lèrgies a la infància, així com la presència d'espècies bacterianes específiques pot ser important per a aquest progrés. A més, les respostes d'IgA alterades cap a la microbiota intestinal durant la infància precedeixen a les manifestacions relatives a la malaltia asmàtica i al·lèrgiques durant els primers 7 anys de vida. Per altra banda, el consum de llet materna amb una microbiota de riquesa reduïda al primer mes de vida podria augmentar el risc de desenvolupar al·lèrgia durant la infància. Els resultats observats en aquest estudi haurien de confirmar-se en cohorts humanes més grans i la importància dels factors ambientals post natals que influeixen en el desenvolupament de la microbiota primerenca han de ser més estudiats. Les investigacions futures deuen anar més enllà de la caracterització de la composició de la comunitat bacteriana i investigar els mecanismes funcionals entre els microorganismes colonitzadors primerencs, la maduració del sistema immunològic i el desenvolupament de l'al·lèrgia i l'asma durant la in[EN] Background: It has been proposed that altered microbial colonization patterns during infancy may be partly responsible for the increase of allergic diseases in developed countries. The gut microbiota differs in composition and diversity during the first months of life in children who later do or do not develop allergic disease. However, little is known about the significance of early mucosal immune responses to the gut microbiota in childhood allergy development, and the findings regarding the protective effect of breastmilk microbiota in the risk of allergy development have been inconclusive. Furthermore, even though the oral cavity is the first site of encounter between a majority of foreign antigens and the immune system, the influence of oral bacteria on allergy development during childhood has not yet been reported. Objectives: The general aim of this thesis was to assess the microbial composition and diversity of oral, fecal and breastmilk samples, together with its interaction with IgA, in order to study the role of microbial development during early childhood in health and allergic disease. Subjects: The infants and mothers included in this study were part of a larger randomized double-blind trial in Sweden, between 2001 and 2003, where potential allergy preventive effects of Lactobacillus reuteri ATCC 55730 were evaluated until 2 and 7 years of age. In this thesis, we used longitudinally collected stool and oral samples from infants, obtained at 1 and 12 months and 3, 6, 12, 24 months and 7 years of age, respectively. Furthermore, we analyzed breastmilk samples, collected at one month post partum, from the corresponding mothers. Methods: Next-generation sequencing technologies targeting the 16S rRNA gene, in combination with cell activated cell sorting, were used in order to address mucosal IgA responses towards gut and breastmilk bacteria. Furthermore, sequencing of the 16S rRNA gene was used in order to describe oral microbiota colonization, in longitudinally obtained saliva samples, from children developing allergy or staying healthy. Bacterial load levels in different microbial habitats were obtained by qPCR methodology and total IgA levels of stool samples were determined by ELISA immunoassays. Results and conclusion: Colonization of the oral cavity during early childhood is transitional, increasing in complexity with time, and several external factors appear to greatly influence oral microbiota maturation, having either a short or a long-term impact. Early changes in oral microbial composition seem to influence immune maturation and allergy development in childhood, and the presence of specific bacterial species may be important for this progress. Furthermore, altered IgA responses towards the gut microbiota during infancy preceded asthma and allergy manifestations during the first 7 years of life, and consumption of breastmilk with a reduced microbial richness in the first month of life may increase the risk for allergy development during childhood. Findings observed here need to be confirmed in larger cohorts and the importance of postnatal environmental factors for early microbiota development should be addressed further. Future research should go beyond characterization of bacterial community composition and investigate the functional mechanisms between early colonizing microorganisms, immune maturation and allergy and asthma development during childhood.Dzidic, M. (2019). Microbiota development and mucosal IgA responses during childhood in health and allergic disease [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/125479TESISCompendi

    Dividend Policies in Volatile Transitioning Markets

    Get PDF
    This paper examines the implicit impact of an individual company financial parameters on dividends payments. The empirical research is conducted within the environment that cross-examines fifteen European transition economies with shared traits of frontier to emerging capital markets development stage and exposure to exogenic global volatility from 2007/8 and Covid-19 economic crises spilling over at magnitude. The purpose of this paper is to test whether companies establish stable dividend policy. Dividends payments are sensitive to earnings and hence adjust imminently. The reason stems from uncertainty on future financial performance and on investor protection. Results yield negative link between solvency and dividends based on the fact that the weaker solvency position decreases the priority of dividends likelihood. Comparably dividends are less desirable if competing with company growth opportunities although investors are less willing to wait for future profits. Altogether transitioning markets are less responsive and structurally feature fewer corporate events

    Inheritance of the birth weights in crosses between Istrian, Awassi, East-Friesian and Travnik Pramenka sheep in Croatia: a case study

    Get PDF
    The purpose of the study was to estimate the influence of the additive and non-additive genetic effects on the birth weight, using two different crossbreed models. Data on 1176 birth weights were collected. The animals were crosses, with different ratios of Awassi, East-Friesian, Istrian, and Travnik Pramenka sheep breed. The focal breed in this study was Istrian, which is an autochthonous breed in Croatia. In both models mixed procedure was used with random effect of sire and fixed effects of sex, year and month of birth, litter size, and direct inbreeding. The first model contained the additive breed effects, while the second model additionally included non-additive effects of heterosis and recombination loss. Sex, litter size, year and month of birth significantly affected birth weight in both models. Effect of direct inbreeding was negative and significant only in second model. Significant positive additive breed effect was estimated for Awassi breed in both models. The East-Friesian additive breed effect was positive in both models, but it was significant for the first one only. The positive and significant heterosis effect for the birth weight was estimated for the crosses between East-Friesian and Travnik Pramenka, as well as between Travnik Pramenka and Istrian breed. Same crosses showed significant and positive effect of recombination loss. The negative effect of recombination loss was estimated for the crosses of Awassi breed

    Multiple-level analysis as a tool for policy: An example of the use of contextualism and causal layered analysis

    Get PDF
    In 1970 Scribner described four types of community psychologists. Despite social change being a common theme, the four types were differentiated by the extent to which they were inside government and organisations or outside, agitating for change. Community psychology and policy change appear to be implicitly connected. Despite this, engagement of community psychologists in policy change has proven to be minimal. Distinctions between first (cosmetic) and second order (systemic) change (Watzlawick, Weakland & Fisch, 1974) reflect the intractability of fundamental change due to deep systemic cultural influences, and should act as a motivator for community psychologists in the policy arena. We argue that psychology’s failure to adopt a multiplicity of epistemologies, in particular a contextualist epistemology, has meant that psychology, and particularly, community psychology has had limited impact. Further, we argue the need to consider community worldviews and culture, in general, if we are to engage more fully in policy development and implementation. Contending with the social issues relevant to policy settings requires an articulation of the worldview and cultural context. Causal layered analysis, a futures methodology, has been adopted to allow a reflective and contextual approach to policy implementation and involves a structured layered deconstruction of social issues. An example of this approach will be highlighted with its application to the implementation of sustainable Australian agricultural policy in the face of climate change.What is revealed is a psychological paradox involving the general endorsement of sustainable policy alongside cultural impediments to its adoption. Community psychologists have a natural and important role to play in policy formulation, given our epistemologies, methodologies and motivation for genuine and transformative social change

    Genetska struktura regionalnih prekograničnih populacija istarske ovce u Hrvatskoj i Sloveniji utvrđena mikrosatelitskim markerima

    Get PDF
    Istrian dairy sheep is a local breed essential for the identity and development of the Northern- Adriatic karstic region through high-quality products, primarily the hard sheep artisanal cheese. Border changes fragmented the initial Istrian dairy sheep population in three genetically isolated sub-populations in Italy (1000 animals), Slovenia (1150 animals) and Croatia (2500 animals). Due to the drastic reduction of their population sizes and fragmentation, the populations in Croatia and Slovenia are included in governmentally supported conservation programs. The initial subpopulation in Italy was restored after near extinction with stock from Slovenia, and is used today in meat production. The aim of this study was to provide an initial understanding of the current genetic structure and distribution of the genetic variability that exists in Istrian sheep by analysing individuals sampled in two regional groups of Istrian sheep from Croatia and Slovenia. Cres island sheep and Lika pramenka sheep were used as out-groups for comparison. Genetic differentiation was analysed using factorial correspondence analysis and structure clustering over 26 microsatellite loci for a total of 104 sheep belonging to three breeds from Croatia and Slovenia. Factorial correspondence analysis and clustering-based structure analysis both showed three distinct populations: Lika pramenka sheep, Cres island sheep and Istrian sheep. We did not find a marked genetic divergence of the regional groups of Istrian sheep. Istrian sheep regional group from Slovenia showed lower genetic variability compared to the one from Croatia. Variability and structure information obtained in this study considered alongside with socio-cultural-contexts and economic goals for the Istrian sheep reared in Croatia and Slovenia indicate that the cross-border exchange of genetic material of animals carrying private alleles among populations would maintain these alleles at low frequencies and minimize the inbreeding rate.Istarska ovca je autohtona pasmina ključna za identitet i razvoj sjevernojadranske regije zbog visokokvalitetnih mliječnih proizvoda. Promjenama granica inicijalna populacija istarske ovce je fragmentirana u tri genetski izolirane sub-populacije u Italiji (1000 životinja), Sloveniji (1150 životinja) i Hrvatskoj (2500 životinja). Zbog fragmentacije i smanjenja veličine populacija, istarske ovce su u Sloveniji i Hrvatskoj uključene u konzervacijske programe državnih potpora. Talijanska populacija je nakon inicijalnog drastičnog smanjenja broja danas obnovljena isključivo iz slovenskih stada. Cilj ovog istraživanja bio je omogućiti razumijevanje današnje genetske strukture i raspodijele genetske raznolikosti istarske ovce istraživanjem slovenske i hrvatske sub-populacije. Creska i lička pramenka korištene su kao grupe za usporedbu. Genetska diferencijacija istražena je faktorijalnom analizom korespondencije i strukturnim klasteriranjem na temelju 26 mikrosatelitskih lokusa genotipiziranih kod 104 ovce. Obje analize pokazale su tri distinktne populacije: lička i creska pramenka, te istarska ovca. Genetička divergencija istarske ovce iz Slovenije i Hrvatske nije izražena. Istarska ovca iz Slovenije pokazala je nižu genetsku varijabilnost od sub-populacije iz Hrvatske. Temeljem informacija o varijabilnosti i strukturi iz ovog istraživanja, kao i društveno-kulturalnog konteksta te ekonomskih ciljeva za slovensku i hrvatsku sub-populaciju istarskih ovaca, može se reći da bi izmjena genetskog materijala životinja s privatnim alelima omogućila održavanje tih alela u niskoj učestalosti, te smanjila genetske posljedice parenja u srodstvu

    Directions for research practice in decolonising methodologies: Contending with paradox

    Get PDF
    The complex nature of colonisation presents with the potential for paradoxes in decolonising approaches, hence, fixed conventions and methods are discouraged. In this way, decolonising methodologies concerns interrogating dominant conventions in research that have typically excluded alternative ways of knowing from academia. This raises concern about the issue of breaking conventions, when it is potentially difficult to realise that one is depending upon them. An incremental approach to the research process and subsequent knowledge generated provides opportunity to challenge the conventions that typically dictate research praxis. In addition, fostering epistemological transformation and pluralism presents a solution to problems derived from dominant cultural assumptions and practices. My aim for this article is to extend upon the literature pertaining to decolonising methodologies, with this contribution of focusing on the research process as a means to avoid paradox in the decolonial intention. Accordingly, a process imperative that focuses on how researchers do research, over the tendency to focus on outcomes, emerges as a strategy to identify and contend with paradoxes within decolonial work. A questioning convention is posited as a means for mining the assumptions and biases of the dominant culture that would otherwise ensnare ones thinking. Consequently, research may be better liberated from oppressive colonising practices that are tacit within research and academic conventions. Narratives are provided throughout for illustrative example, and to better explore the concepts named

    The Australian Mainstream Media’s Portrayal of Youth Climate Activism and Dissent

    Get PDF
    The March 2019 School Strikes 4 Climate, predominantly organized by young students, garnered widespread and polarizing media coverage. We aimed to identify how Australian mainstream print news media portrays youth involvement and dissent within climate action movements. A qualitative media framing analysis was conducted to determine how youth climate activists and dissent were presented during the first large-scale youth climate protests in Australia. Australian newspaper articles and opinion pieces (N = 101) were identified via ProQuest and screened. An inductive thematic analysis was conducted in NVivo12. Findings were assessed through a typology of dissent to determine how different forms of dissent were represented in the Australian print news media. The framing of dissent in Australian media coverage was varied, with news articles being more likely to prioritize the voices of young people, while opinion pieces resorted to fear-mongering rhetoric that critiqued and invalidated their agency. Protestors used combinations of dutiful and disruptive dissent to advocate for climate action, with the latter being more effective for challenging systemic drivers of climate change

    Genetic parameters for the external udder morphology in commercial farms of Istrian sheep from Croatia

    Get PDF
    Istrian sheep is a local breed with superior milk yield and composition. Excellent udder shape of this breed needs to be preserved in future, since it’s economic value resides within the artisanal cheese production. Genetic parameters for the teat angle (Alpha) and the height of the cisternal part below the teat orifice (Cis) were estimated in order to evaluate the possibility for conservation of udder traits amiable for machine milking. Udder morphometry of the 240 registered Istrian ewes was measured from digital photographs of the posterior view of the udder on 10 commercial farms three times during lactation. Original pedigree records were trimmed to four recent generations. Heritabilities were estimated using single trait animal model. The stage of the lactation, interaction of lactation number, month of lambing and the farm were fixed effects, and the additive genetic value of the individual and permanent environment of the individual were random effects. Estimated heritability was 0.05 for Alpha and 0.71 for Cis mid-lactation measurements. Measurements of Cis during lactation did not result in a significant additive effect. The result shows potential in estimating genetic parameters of important udder traits in small commercial dairy ewe populations, using the digital measurements, given the reduction of non-genetic variability in the sample

    The effect of various automatic cluster removal switch-point settings on milking and overmilking duration and total, peak and overmilking claw vacuum in dairy cows

    Get PDF
    This research communication describes the effect of three automatic cluster removal (ACR) switch-point settings on machine-on time, overmilking duration, and the mean, peak-flow and overmilking vacuums. The objective was to reduce the overmilking and milking time, attaining a lower mean claw vacuum during overmilking. In a randomised experiment, 25 cows were subjected to three ACR switch-point settings at flow rates of 0.840 kg/min, 0.630 kg/min and 0.504 kg/min each for 15 morning-milkings. Pre-milking preparations and cow comfort were observed and evaluated, showing evidence that the switch-point setting of 0.840 kg/ml denoted the least proportion of behavioural problems (1.1% ± 0.6) compared to the settings at 0.640 kg/ml (16.0% ± 2.2) and 0.504 kg/ml (9.4% ± 1.7). A VaDia device (Biocontrol) determined the machine-on time and vacuum levels at the claw, mouthpiece and pulsator chamber. The machine-on time varied from 290 ± 72.8 (mean ± sd) to 289 ± 64.4 and 303 ± 66.3 for the 0.840, 0.630 and 0.504 kg/min settings, respectively. Overmilking was shortened by 29.3% and 26.4% and the claw vacuum during overmilking was reduced by 3.7 kPa and 4.3 kPa when using the 0.840 kg/min switch-point setting, compared to the others. An increased cluster-removal milk flow threshold reduced both overmilking and vacuum level during overmilking, lowering the risk of teat damage. Adapting ACR switch-point settings offers a valuable opportunity to increase parlour efficiency and cow comfort in dairy herds.The National Research Foundation (NRF) and Milk South Africa partly supported this research.https://www.cambridge.org/core/journals/journal-of-dairy-researchhj2023Production Animal Studie

    Assessing the Impact of Stakeholder Engagement in Management Strategy Evaluation

    Get PDF
    After completing a large, regional, multi-use Management Strategy Evaluation, we attempt to assess the impact of stakeholder engagement on the project. We do so by comparing the original project plan to the actual project development and highlight the changes which can be more directly related to stakeholder engagement aided by the application of a logic model for program evaluation. The impact can be summarised into four broad classes: a) change in the actual project development; b) a measurable change in the network of interactions both stakeholders (which includes researchers); c) changes in how the computer model was developed and run; and d) changes in attitudes among stakeholders (including researchers). We discuss these changes, the way they have been detected and some lessons we learnt which may benefit future Management Strategy Evaluation projects
    corecore