557 research outputs found

    The Sierpinski Object in the Scott Realizability Topos

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    We study the Sierpinski object Σ\Sigma in the realizability topos based on Scott's graph model of the λ\lambda-calculus. Our starting observation is that the object of realizers in this topos is the exponential ΣN\Sigma ^N, where NN is the natural numbers object. We define order-discrete objects by orthogonality to Σ\Sigma. We show that the order-discrete objects form a reflective subcategory of the topos, and that many fundamental objects in higher-type arithmetic are order-discrete. Building on work by Lietz, we give some new results regarding the internal logic of the topos. Then we consider Σ\Sigma as a dominance; we explicitly construct the lift functor and characterize Σ\Sigma-subobjects. Contrary to our expectations the dominance Σ\Sigma is not closed under unions. In the last section we build a model for homotopy theory, where the order-discrete objects are exactly those objects which only have constant paths

    Immunity in barren and enriched housed pigs differing in baseline cortisol concentration

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    It was shown recently that barren housed pigs (small pens, no substrate) have a blunted circadian rhythm of salivary cortisol as compared to enriched housed pigs (large pens with daily fresh bedding). In the light period, enriched housed pigs showed significantly higher concentrations of cortisol in saliva than barren housed pigs, whereas in the dark period, cortisol concentrations were low in both enriched and barren housed pigs. In the present study, the immunological consequences of the difference in baseline salivary cortisol concentration in the light period were evaluated. It appeared that leukocyte and lymphocyte distributions, and in vitro lymphocyte proliferation following ConcanavalineA (ConA) stimulation in the assay using purified lymphocytes were not affected. However, barren and enriched housed pigs did show a different proliferation response to ConA in the whole blood assay. At day 2 of culture, proliferation was higher in barren housed pigs than in enriched housed pigs, whereas at day 4 of culture, proliferation was higher in enriched housed pigs than in barren housed pigs. Lymphocyte proliferation at day 2 of culture in the whole blood assay correlated negatively with plasma cortisol levels, which might thus explain the higher proliferation in barren housed pigs at day 2 of culture. The in vivo humoral and cellular (delayed type hypersensitivity, DTH) immune response to KLH was not affected by housing conditions. We conclude that, although baseline salivary cortisol concentrations differ between enriched and barren housed pigs, immune function appears to be relatively unaffected.

    The Genre of the Royal Crisis Address: Six European Monarchs’ Rhetorical Responses to the Covid-19 Pandemic

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    This article offers a rhetorical analysis of the addresses delivered by six Northern European monarchs in response to the Covid-19 pandemic in early 2020. The analysis establishes a new genre with distinctive traits and functions: They royal crisis address. This genre has two constitutive traits: To demonstrate the seriousness of the situation and to constitute the citizens and encourage them to behave in the right way. The genre also has three optional traits: to provide thanks, to empathise with those affected, and to reassure and inspire the nation. In a national crisis such as the Covid-19 pandemic, these rhetorical functions will also be performed by national leaders, however, because of the apolitical position and charismatic and historical power of the royals in the North European monarchies the royals can perform these functions with a special authority. We describe how this is done through the five functions and through epideictic and constitutive rhetoricpublishedVersio

    Enhanced sensitivity of postsynaptic serotonin-1A receptors in rats and mice with high trait aggression

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    Individual differences in aggressive behaviour have been linked to variability in central serotonergic activity, both in humans and animals. A previous experiment in mice, selectively bred for high or low levels of aggression, showed an up-regulation of postsynaptic serotonin-1A (5-HT1A) receptors, both in receptor binding and in mRNA levels, in the aggressive line. The aim of this experiment was to study whether similar differences in 5-HT1A receptors exist in individuals from a random-bred rat strain, varying in aggressiveness. In addition, because little is known about the functional consequences of these receptor differences, a response mediated via postsynaptic 5-HT1A receptors (i.e., hypothermia) was studied both in the selection lines of mice and in the randomly bred rats. The difference in receptor binding, as demonstrated in mice previously, could not be shown in rats. However, both in rats and mice, the hypothermic response to the 5-HT1A agonist alnespirone was larger in aggressive individuals. So, in the rat strain as well as in the mouse lines, there is, to a greater or lesser extent, an enhanced sensitivity of postsynaptic 5-HT1A receptors in aggressive individuals. This could be a compensatory up-regulation induced by a lower basal 5-HT neurotransmission, which is in agreement with the serotonin deficiency hypothesis of aggression.

    El modelo de consenso sobre el Sistema de Certificación en Docencia en Educación Superior en Holanda: un fenómeno típicamente holandés

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    [EN] This article describes the process which led to the introduction of a University Teaching Qualification (UTQ) at research universities in the Netherlands. Until 2008, the only requirements to get appointed as a lecturer at most Dutch research universities pertained to research competences. This changed in 2008 when all Dutch research universities signed the Mutual Agreement of University Teaching Qualification. In 2005 staff developers of six universities initiated a working group to support the idea of a mutual agreement of the UTQ. Their initiative was taken over by two Vice Chancellors but at that time there was no consensus between all the research universities. This changed by political pressure of the Ministry of Education and student unions. The Dutch UTQ is mandatory, but not by law. The UTQ Agreement describes the scheme that concerns the embedding of the UTQ certification procedures in the participating universities. The mutual recognition of the UTQ is an example of a typical Dutch phenomenon called the Polder Model a strategy of consensus based policy making and a pragmatic recognition of pluriformity.[ES] El artículo describe el proceso que condujo a la introducción de un título de enseñanza universitaria (UTQ) en las universidades de investigación en los Países Bajos. Hasta 2008, los únicos requisitos para ser profesor en la mayoría de las universidades de investigación holandeses se remitían a competencias en investigación. Esto cambió en 2008, cuando todas las universidades de investigación holandeses firmaron el Acuerdo Mutuo de la Universidad de Cualificación Docente. En 2005 los formadores de seis universidades iniciaron un grupo de trabajo para apoyar la idea de un acuerdo mutuo sobre la UTQ. Su iniciativa fue asumida por dos Rectores, sin que hubiera consenso entre todas las universidades de investigación. Esto cambió por la presión política de la Consejería de Educación y los sindicatos de estudiantes. Ahora el UTQ es obligatorio, pero no por la ley. El Acuerdo UTQ describe el esquema que se refiere a la incorporación de los procedimientos de certificación UTQ en las universidades participantes. El reconocimiento mutuo de la UTQ es un ejemplo de un típico fenómeno holandés, el modelo pólder, una estrategia basada en el consenso en la formulación de políticas y un reconocimiento pragmático de la pluriformidad.De Jong, R.; Mulder, J.; Deneer, P.; Van Keulen, H. (2013). Poldering a teaching qualification system in Higher Education in the Netherlands: a typical Dutch phenomenon. REDU. Revista de Docencia Universitaria. 11(3):23-40. https://doi.org/10.4995/redu.2013.5517OJS2340113Association of Universities in the Netherlands/ VSNU (2008). Mutual agreement on a national framework of a University Teaching Qualification System (Overeenkomst Wederzijdse erkenning Basiskwalificatie Onderwijs: BKO). The Hague.Board of the University of Groningen (2013). University of Groningen Critical Reflection 2013. GroningenGerritsen, R.J., Jong, R. de, & Alst, J. M. T. van (2004). Toetsen van docentcompetenties: professionaliseringsbeleid voor docenten. TH&MA, 2004(5), 53-61.Gibbs, G. (2005). NTFS Report on Utrecht University. Oxford: NTFS.Jong, R. de (2012). Teaching competencies: qualification frameworks and external audits. The Dutch example: how to unite uniformity and flexibility. Lecture presented at the annual RED-U meeting, 02-02-1012 Bilbao, Spain.Jong, R. de, & Keulen, H. van. (2007) De lange weg naar competente én gekwalificeerde docenten, Onderzoek van Onderwijs, 36/3, 44-47.Jong, R. de, Alst, J. van, Andernach, T., Baume, D., Diez, A., Keulen, H. van, Petegem, P. van (2010). International agreement on a Qualification for University Teaching, Let's make a start as experts in staff development. Workshop at the ICED Conference 2010, Barcelona, Spain.Jong, R. de, Andernach, T., Barendsen, E. & Mulder, J. (2011). Externe kwaliteitsborging BasisKwalificatie Onderwijs in de Praktijk, Een onderzoek naar een bruikbaar auditsysteem'. The Hague: SoFoKles.Keesen, F., Wubbels, T., Tartwijk, J. van, & Bouhuijs, P. A. J. (1996). Preparing university teachers in The Netherlands: Issues and trends. International Journal for Academic Development, 1(2), 8-16.Keulen, J.van, Alst, J. van, Jong, R. de, & Halma, A. (2006). Towards a national system of teaching qualifications in higher education in the Netherlands. Paper presented at the ICED Conference 2006, Sheffield, EnglandKeulen, H. van, Jong, R de, Deneer, P. (2008). Characteristics of successful faculty development programs. Paper presented at the ICED Conference 2008, Salt Lake City, USA.Kranenburg, M. (1999), The political branch of the polder model, The economist (May 2002) ModelmakersMulder, J.A., Jong, R. A.H. de & Andernach, J.A. (2012). University Teaching Qualification: Quality assurance via external audits in the Netherlands. Paper presented at the 2012 ICED conference, Bangkok, Thailand

    Personalities in female domesticated pigs: behavioural and physiological indications

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    The inconclusive evidence so far on the existence of distinct personality types in domesticated pigs, led us to perform the present experiment. A total of 128 gilts from 31 sows were systematically studied from birth to slaughter in two identical trials. Intra-test consistency in individual behavioural andror physiological reactions was studied in three different tests. We were not able to show consistencies in reactions of gilts over time to a backtest (at 2–4 days and 4 weeks of age) and to a novel environment test (at 10 and 24 weeks of age). Individual aggression, however, as measured in a group-feeding competition test in stable groups (at 10 and 24 weeks of age), proved to be highly consistent. Explanations for these discrepancies in intra-test consistencies are critically discussed. Inter-test consistencies were determined by relating the individual reactions of gilts to the backtest to various characteristics and responses to tests at a later age. The highest correlations were found when resistance in the first backtest was involved. No evidence was found for the existence of specific isolated categories of animals with respect to this resistance. For further analysis, extreme responding gilts in the first backtest (roughly the top and bottom 25% of the distribution) were classified as low resistant (LR; <3 escape attempts; n=31) or high resistant (HR; >4 escape attempts; n=45). By comparisons of mean responses of LR and HR gilts within groups, we have established a relationship between the backtest and several other variables. Behaviourally, the HR gilts showed more aggression in the group-feeding competition tests. Also, in the competition for the most productive teats at the anterior, a predominant position of HR piglets at this site was observed during the suckling period. The latter piglets also gained more weight during this period than LR ones. Compared to HR pigs, in the first novel environment test LR pigs hesitated longer to leave their home pens and to contact a human, but no difference in their locomotory behaviour was observed. Contrasts between LR and HR pigs in the second novel environment test were reduced or absent. Physiologically, when compared to HR gilts, LR ones had a higher reactivity of the hypothalamic–pituitary–adrenocortical (HPA) system. This was shown by higher cortisol responses to the first novel environment test, to routine weighing at 25 weeks of age, and to administration of a high dose of ACTH. It is discussed that these findings for LR and HR gilts, may provide support for the existence of behavioural and physiological responses in pigs, resembling those of proactive and reactive rodents.

    Effects of environmental enrichment on behavioral responses to novelty, learning, and memory, and the circadian rhythm in cortisol in growing pigs

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    Previously we showed that pigs reared in an enriched environment had higher baseline salivary cortisol concentrations during the light period than pigs reared under barren conditions. In the present experiment, it was investigated whether these higher baseline salivary cortisol concentrations were a real difference in cortisol concentration or merely represented a phase difference in circadian rhythm. The effects of different cortisol concentrations on the behavioral responses to novelty and learning and long-term memory in a maze test were also studied in enriched and barren housed pigs. At 9 weeks of age enriched and barren housed pigs did not differ in baseline salivary cortisol concentrations nor in circadian rhythm, but at 22 weeks of age barren housed pigs had a blunted circadian rhythm in salivary cortisol as compared to enriched housed pigs. The differences in baseline salivary cortisol concentrations between enriched- and barren-housed pigs are age-dependent, and become visible after 15 weeks of age. Enriched- and barren-housed piglets did not differ in time spent on exploration in the novel environment test. Barren-housed pigs had an impaired long-term memory in the maze test compared to enriched-housed pigs; however, no differences in learning abilities between enriched- and barren-housed pigs were found. Because blunted circadian cortisol rhythms are often recorded during states of chronic stress in pigs and rats or during depression in humans, it is suggested that the blunted circadian rhythm in cortisol in barren-housed pigs similarily may reflect decreased welfare.

    The Sierpinski Object in the Scott Realizability Topos

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    We study the Sierpinski object Σ\Sigma in the realizability topos based on Scott's graph model of the λ\lambda-calculus. Our starting observation is that the object of realizers in this topos is the exponential ΣN\Sigma ^N, where NN is the natural numbers object. We define order-discrete objects by orthogonality to Σ\Sigma. We show that the order-discrete objects form a reflective subcategory of the topos, and that many fundamental objects in higher-type arithmetic are order-discrete. Building on work by Lietz, we give some new results regarding the internal logic of the topos. Then we consider Σ\Sigma as a dominance; we explicitly construct the lift functor and characterize Σ\Sigma-subobjects. Contrary to our expectations the dominance Σ\Sigma is not closed under unions. In the last section we build a model for homotopy theory, where the order-discrete objects are exactly those objects which only have constant paths

    Climbing droplets driven by mechanowetting on transverse waves

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    Many applications in modern technology, such as self-cleaning surfaces and digital microfluidics, require control over individual fluid droplets on flat surfaces. Existing techniques may suffer from side effects resulting from high electric fields and high temperatures. Here, we introduce a markedly different method, termed "mechanowetting," that is based on the surface tension-controlled droplet motion on deforming surfaces. The method is demonstrated by transporting droplets using transverse surface waves on horizontal and (vertically) inclined surfaces at transport velocities equal to the wave speed. We fully capture the fundamental mechanism of the mechanowetting force numerically and theoretically and establish its dependence on the fluid properties, surface energy, and wave parameters. Mechanowetting has the potential to lead to a range of new applications that feature droplet control through dynamic surface deformations.</p
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