1,365 research outputs found

    A missing dimension in measures of vaccination impacts

    Get PDF
    Immunological protection, acquired from either natural infection or vaccination, varies among hosts, reflecting underlying biological variation and affecting population-level protection. Owing to the nature of resistance mechanisms, distributions of susceptibility and protection entangle with pathogen dose in a way that can be decoupled by adequately representing the dose dimension. Any infectious processes must depend in some fashion on dose, and empirical evidence exists for an effect of exposure dose on the probability of transmission to mumps-vaccinated hosts [1], the case-fatality ratio of measles [2], and the probability of infection and, given infection, of symptoms in cholera [3]. Extreme distributions of vaccine protection have been termed leaky (partially protects all hosts) and all-or-nothing (totally protects a proportion of hosts) [4]. These distributions can be distinguished in vaccine field trials from the time dependence of infections [5]. Frailty mixing models have also been proposed to estimate the distribution of protection from time to event data [6], [7], although the results are not comparable across regions unless there is explicit control for baseline transmission [8]. Distributions of host susceptibility and acquired protection can be estimated from dose-response data generated under controlled experimental conditions [9]–[11] and natural settings [12], [13]. These distributions can guide research on mechanisms of protection, as well as enable model validity across the entire range of transmission intensities. We argue for a shift to a dose-dimension paradigm in infectious disease science and community health

    Valorisation of red beet waste: one-step extraction and separation of betalains and chlorophylls using thermoreversible aqueous biphasic systems

    Get PDF
    Globally, up to 50% of root crops, fruits and vegetables produced is wasted. Beetroot stems and leaves fit into this scenario, with only a small fraction being used in cattle food. One way of approaching this problem is through their valorisation, by extracting and recovering valuable compounds present in this type of waste that could be used in other applications, while contributing towards a circular economy. In this work, a new integrated process using thermoreversible aqueous biphasic systems (ABS) composed of quaternary ammonium-based ionic liquids (ILs) and polypropyleneglycol 400 g mol−1 (PPG) is shown to allow the one-step extraction and separation of two pigment classes—betalains and chlorophylls—from red beet stems and leaves. The pigment extraction was carried out with a monophasic aqueous solution of the IL and PPG, whose phase separation was then achieved by a temperature switch, resulting in the simultaneous separation of chlorophylls and betalains into opposite phases. A central composite design was used to optimise the extraction parameters (time, temperature, and solid : liquid (S/L) ratio) of both pigment extraction yields, reaching at 20 °C, 70 min and a S/L ratio of 0.12 a maximum extraction yield of 6.67 wt% for betalains and 1.82 wt% for chlorophylls (per weight of biomass). Moreover, it is shown that aqueous solutions of ILs better stabilise betalains than the gold standard solvent used for the extraction method. Among the studied systems, the ABS comprising the IL N-ethyl-N-methyl-N,N-bis(2-hydroxyethyl) bromide ([N21(2OH)(2OH)]Br) presented the best separation performance, with an extraction efficiency of 92% and 95% for chlorophylls and betalains, respectively, for opposite phases. The pigments were removed from the respective phases using affinity resins, with high recoveries: 96% for betalains and 98% for chlorophylls, further allowing the IL reuse. Finally, the cyto- and ecotoxicities of the quaternary ammonium-based ILs were determined. The obtained results disclosed low to negligible toxicity in the thousands of mg L−1 range, with [N21(2OH)(2OH)]Br being harmless from an ecotoxicological point of view. Overall, it is shown here that the developed process is an innovative approach for the one-step extraction and selective separation of pigments contributing to the valorisation of waste biomass

    Distribution of populations of broad-snouted caiman (Caiman latirostris, Daudin 1802, Alligatoridae) in the São Francisco River basin, Brazil

    Get PDF
    We surveyed populations of the broad-snouted caiman, Caiman latirostris, throughout the São Francisco River basin, from Três Marias reservoir, State of Minas Gerais, to the river delta, at the boarder of Sergipe and Alagoas states. We registered the occurrence of crocodilians in 61% of all surveyed localities (n = 64), in which the presence of C. latirostris was confirmed in 44% of the surveyed sites. Caimans occurred in both lentic and lotic habitats, although there was a preference for small dams, oxbow lakes and wetlands. Despite the hunting pressure and human impact on natural habitats, our results indicate that the populations of C. latirostris in the São Francisco basin are not fragmented

    TUIs vs. GUIs : comparing the learning potential with preschoolers

    Get PDF
    In an effort to better understand the learning potential of a tangible interface, we conducted a comparison study between a tangible and a traditional graphical user interface for teaching preschoolers (In Portugal, children enter preschool at the age of three and they attend it till entering school, normally at the age of six) about good oral hygiene. The study was carried with two groups of children aged 4 to 5 years. Questionnaires to parents, children’s drawings, and interviews were used for data collection and analysis and revealed important indicators about children’s change of attitude, involvement, and preferences for the interfaces. The questionnaires showed a remarkable change of attitude toward tooth brushing in the children that interacted with the tangible interface; particularly children’s motivation increased significantly. Children’s drawings were used to assess their degree of involvement with the interfaces. The drawings from the children that interacted with the tangible interface were very complete and detailed suggesting that the children felt actively involved with the experience. The results suggest that the tangible interface was capable of promoting a stronger and long-lasting involvement having a greater potential to engage children, therefore potentially promoting learning. Evaluation through drawing seems to be a promising method to work with preliterate children; however,it is advisable to use it together with other methods.Fundação para a Ciência e Tecnologia (FCT

    Study of intrinsic risk factors for falls in institutionalized elderly people

    Get PDF
    Esta pesquisa teve como objetivo identificar a presença de fatores intrínsecos que predispõem a quedas em idosos moradores em instituições de longa permanência na cidade de Goiânia (GO). Trata-se de estudo descritivo transversal realizado em seis instituições de longa permanência para idosos existentes na cidade de Goiânia. A amostra da investigação constou de 95 idosos que atenderam aos critérios de inclusão e exclusão. Utilizou-se um questionário contendo dados clínicos relacionados às condições de saúde-doença; dados cognitivos; avaliação da capacidade para as atividades básicas de vida diária e avaliação do equilíbrio e marcha. Os idosos avaliados, no geral, apresentam vários fatores de risco, apontados pela literatura, para quedas, tais como: relato de dificuldade motora em membros inferiores (90%), déficit visual (81,1%), uso de três ou mais medicamentos (59,7%), suspeita de depressão (37,9%), falta de equilíbrio em apoio unipodal (37,9%) e altura do passo anormalmente diminuída (32,6%). As informações obtidas nos permitem apontar condições determinantes que aumentam a possibilidade dos eventos queda acontecerem na amostra estudada, sinalizando à necessidade de que estratégias de promoção de saúde, prevenção de agravos e reabilitação devam ser tomadas. _________________________________________________________________________________________ ABSTRACTThe objective of this research was to identify intrinsic risk factors that predispose elderly people living in long-term institutions in the city of Goiânia (GO) to falls. The present descriptive transversal study was carried out in six long-term institutions for seniors in the city of Goiânia. The investigated sample consisted of 95 elderly that fitted the inclusion and exclusion criteria. A questionnaire was used for collecting clinical data related to health-disease conditions; cognitive data; capacity to develop basic daily life activities and equilibrium and gait. In general terms, as pointed out the literature, the examined elderly presented different fall risk factors such as: motor difficulty in lower limbs (90%), visual deficit (81,1%), use of 3 or more kinds of medicines (59,7%), suspected depression (37,9%), lack of equilibrium/unstable unipodal support (37,9%) abnormally decreased height in step (32,6%). The obtained data allow us to set indicators for the increase in falls among the studied sample, demonstrating the need for creating strategies for health promotion, prevention of injuries and rehabilitation

    Perinatal outcomes associated with low birth weight in a historical cohort

    Get PDF
    <p>Abstract</p> <p>Objective</p> <p>To identify perinatal outcomes associated with low birth weight (LBW).</p> <p>Methods</p> <p>A retrospective cohort study in a tertiary maternity hospital. Analysis of the database on 43,499 liveborn infants delivered between 1986 and 2004 with low (n = 6,477) and normal (n = 37,467) birth weight. Outcomes associated with LBW were identified through crude and adjusted risk ratio (RR) and 95%CI with bivariate and multivariate analysis. The main outcomes were: onset of labor, mode of delivery, indication for cesarean section; amniotic fluid, fetal heart rate pattern, Apgar score, somatic gestational age, gender and congenital malformation.</p> <p>Results</p> <p>LBW infants showed more frequently signs of perinatal compromise such as abnormal amniotic fluid volume (especially olygohydramnios), nonreassuring patterns of fetal heart rate, malformation, lower Apgar scores and lower gestational age at birth. They were associated with a greater risk of labor induction and cesarean delivery, but lower risk of forceps.</p> <p>Conclusion</p> <p>There was a clear association between LBW and unfavorable perinatal outcomes.</p
    corecore