7,763 research outputs found

    Adaptable history biases in human perceptual decisions

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    When making choices under conditions of perceptual uncertainty, past experience can play a vital role. However, it can also lead to biases that worsen decisions. Consistent with previous observations, we found that human choices are influenced by the success or failure of past choices even in a standard two-alternative detection task, where choice history is irrelevant. The typical bias was one that made the subject switch choices after a failure. These choice history biases led to poorer performance and were similar for observers in different countries. They were well captured by a simple logistic regression model that had been previously applied to describe psychophysical performance in mice. Such irrational biases seem at odds with the principles of reinforcement learning, which would predict exquisite adaptability to choice history. We therefore asked whether subjects could adapt their irrational biases following changes in trial order statistics. Adaptability was strong in the direction that confirmed a subject's default biases, but weaker in the opposite direction, so that existing biases could not be eradicated. We conclude that humans can adapt choice history biases, but cannot easily overcome existing biases even if irrational in the current context: adaptation is more sensitive to confirmatory than contradictory statistics

    In silico and expression analyses of fasciclin-like arabinogalactan proteins reveal functional conservation during embryo and seed development

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    Fasciclin-like arabinogalactan proteins (FLAs) are a subclass of arabinogalactan proteins (AGPs), which contain fasciclin-like domains in addition to typical AGP domains. FLAs are present across all embryophytes, and despite their low overall sequence similarity, conserved regions that define the fasciclin functional domain (FAS) have been identified, suggesting that the cell adhesion property is also conserved. FLAs in Arabidopsis have been organized into four subgroups according to the number and distribution of functional domains. Recent studies associated FLAs with cell wall-related processes where domain organization seemed to be related to functional roles. In Arabidopsis, FLAs containing a single FAS domain were found to be important for the integrity and elasticity of the plant cell wall matrix, and FLAs with two FAS domains and two AGP domains were found to be involved in maintaining proper cell expansion under salt stress conditions. The main purpose of the present work was to elucidate the expression pattern of selected FLA genes during embryo and seed development using RT-qPCR. AtFLA8 and AtFLA10, two Arabidopsis genes that stood out in previous microarray studies of embryo development, were further examined using promoter-driven gene reporter analyses. We also studied the expression of cork oak FLA genes and found that their expression partially parallels the expression patterns of the putative AtFLA orthologs. We propose that the functional organization of FLAs is conserved and may be related to fundamental aspects of embryogenesis and seed development across angiosperms. Phylogenetic studies were performed, and we show that the same basic four-subgroup organization described for Arabidopsis FLA gene classification is valid for most Arabidopsis FLA orthologs of several plant species, namely poplar, corn and cork oak

    Comparison of DeLorme with Oxford resistance training techniques: effects of training on muscle damage markers

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    Aim: The purpose of this study was comparing DeLorme with Oxford methods through ten repetition maximum (10 RM) performance and serum creatine kinase (CK) and lactate dehydrogenase (LDH) activity. Methods: Before and after four weeks of training with the DEL (n=16) or OXF (n=16) resistance training (RT) methods, rest and post exercise serum CK activity, serum LDH activity and 10 RM performance were measured and compared. Results: Both methods provide higher 10 RM results after training without significant differences between groups (p<0.05). Rest and post exercise CK and LDH activity was less after training with DeLorme (DEL) and Oxford (OXF), but the magnitude of the relative peak response (48-hr our 72-hr post exercise, respectively) was higher after each training protocol. Comparisons of CK activity between groups display non-significant differences. Conclusion: DEL or OXF training methods cause the same improvement on muscle performance and both alters CK activity without differences between methods in a 4-week RT program

    Distributed design of product oriented manufacturing systems

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    Manufacturing leanness and agility are requirements of today’s manufacturing systems. Leanness call for a best fit of the manufacturing systems to products, therefore requiring product oriented manufacturing systems (POMS). Manufacturing agility can be achieved through easy systems reconfiguration to fit changing manufacturing requirements, which may mean dynamically configuring POMS. For this a suitable design system is required. Due to complexity of this design, and to the need for using suitable design methods, which may not be available locally, distributed sources of design services can be used. This paper presents and describes a prototype of a Distributed Design system for POMS based on a POMS design methodology and distributed suppliers of design services

    A NEW METHODOLOGY FOR DIAGNOSIS OF FANCONI ANEMIA BASED ON BIOLOGICAL DOSIMETRY

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    Fanconi Anemia (FA) is a syndrome associated with chromosomal fragility. Current laboratory tests to diagnose this disease are based on the scoring of chromosomal aberrations induced in peripheral blood lymphocytes by clastogenic chemical agents, mainly: diepoxybutane (DEB) or mitomycin C (MMC). This study evaluated an alternative test for the diagnosis of FA, in which ionizing radiation replaces DEB/MMC. Two groups were studied: normal and DEB-sensitive individuals. From each individual, samples of peripheral blood were irradiated using an electron linear accelerator. Following lymphocyte cultures, and slide preparation, metaphases were scored based on the same methodology for biological dosimetry, according to recommendations of the International Atomic Energy Agency. Our results emphasized a pattern of distribution of dicentrics, fragments, as well as abnormal chromosomal arrangements. The methodology of analysis here proposed permitted to distinguish normal from DEB-sensitive subjects

    Breaking Barriers: Bioinspired Strategies for Targeted Neuronal Delivery to the Central Nervous System

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    Central nervous system (CNS) disorders encompass a vast spectrum of pathological conditions and represent a growing concern worldwide. Despite the high social and clinical interest in trying to solve these pathologies, there are many challenges to bridge in order to achieve an effective therapy. One of the main obstacles to advancements in this field that has hampered many of the therapeutic strategies proposed to date is the presence of the CNS barriers that restrict the access to the brain. However, adequate brain biodistribution and neuronal cells specific accumulation in the targeted site also represent major hurdles to the attainment of a successful CNS treatment. Over the last few years, nanotechnology has taken a step forward towards the development of therapeutics in neurologic diseases and different approaches have been developed to surpass these obstacles. The versatility of the designed nanocarriers in terms of physical and chemical properties, and the possibility to functionalize them with specific moieties, have resulted in improved neurotargeted delivery profiles. With the concomitant progress in biology research, many of these strategies have been inspired by nature and have taken advantage of physiological processes to achieve brain delivery. Here, the different nanosystems and targeting moieties used to achieve a neuronal delivery reported in the open literature are comprehensively reviewed and critically discussed, with emphasis on the most recent bioinspired advances in the field. Finally, we express our view on the paramount challenges in targeted neuronal delivery that need to be overcome for these promising therapeutics to move from the bench to the bedside.This work was financially supported by the project PTDC/CTM-NAN/3547/2014 (POCI-01-0145-FEDER-016639) funded by FEDER funds through the Programa Operacional Competitividade e Internacionalização-COMPETE 2020 and Portuguese funds through FCT–Fundação para a Ciência e a Tecnologia. A.P.S., B.C. and S.D.S. acknowledge FCT for the Ph.D. scholarships (SFRH/BD/137073/2018 and SFRH/BD/145652/2019) and the contract under the Norma Transitória–DL57/2016/CP/CP1360/CT0013, respectively. V.L. acknowledges her contract in the framework of the project NORTE-01-0247-FEDER-033399, funded by FEDER funds through the Sistema de Incentivos à Investigação e Desenvolvimento Tecnológico (SI I&DT), Aviso nº 03/SI/2017, Projetos em Co-promoção do Programa Interfac

    Can we use postal surveys with anonymous testing to monitor chlamydia prevalence in young women in England? Pilot study incorporating randomised controlled trial of recruitment methods

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    OBJECTIVES: Chlamydia prevalence in the general population is a potential outcome measure for the evaluation of chlamydia control programmes. We carried out a pilot study to determine the feasibility of using a postal survey for population-based chlamydia prevalence monitoring. METHODS: Postal invitations were sent to a random sample of 2000 17-year-old to 18-year-old women registered with a general practitioner in two pilot areas in England. Recipients were randomised to receive either a self-sampling kit (n=1000), a self-sampling kit and offer of £5 voucher on return of sample (n=500) or a self-sampling kit on request (n=500). Participants returned a questionnaire and self-taken vulvovaginal swab sample for unlinked anonymous Chlamydia trachomatis testing. Non-responders were sent a reminder letter 3 weeks after initial invitation. We calculated the participation rate (number of samples returned/number of invitations sent) and cost per sample returned (including cost of consumables and postage) in each group. RESULTS: A total of 155/2000 (7.8%) samples were returned with consent for testing. Participation rates varied by invitation group: 7.8% in the group who were provided with a self-sampling kit, 14% in the group who were also offered a voucher and 1.0% in the group who were not sent a kit. The cost per sample received was lowest (£36) in the group who were offered both a kit and a voucher. CONCLUSIONS: The piloted survey methodology achieved low participation rates. This approach is not suitable for population-based monitoring of chlamydia prevalence among young women in England

    Epistasis not needed to explain low dN/dS

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    An important question in molecular evolution is whether an amino acid that occurs at a given position makes an independent contribution to fitness, or whether its effect depends on the state of other loci in the organism's genome, a phenomenon known as epistasis. In a recent letter to Nature, Breen et al. (2012) argued that epistasis must be "pervasive throughout protein evolution" because the observed ratio between the per-site rates of non-synonymous and synonymous substitutions (dN/dS) is much lower than would be expected in the absence of epistasis. However, when calculating the expected dN/dS ratio in the absence of epistasis, Breen et al. assumed that all amino acids observed in a protein alignment at any particular position have equal fitness. Here, we relax this unrealistic assumption and show that any dN/dS value can in principle be achieved at a site, without epistasis. Furthermore, for all nuclear and chloroplast genes in the Breen et al. dataset, we show that the observed dN/dS values and the observed patterns of amino acid diversity at each site are jointly consistent with a non-epistatic model of protein evolution.Comment: This manuscript is in response to "Epistasis as the primary factor in molecular evolution" by Breen et al. Nature 490, 535-538 (2012
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