Olfactory learning, its development and changing role in Honeybee (Apis Mellifera) behaviour

The honeybee (Apis mellifera) is capable of showing a wide variety of cognitive tasks, and can be readily conditioned in the laboratory to specific odours, paired with a sucrose reward, using the proboscis extension reflex (PER) learning paradigm. This thesis aims to establish any differences in the behavioural parameters of this olfactory learning. A strong, repeatable methodology is developed, and this specificity of the learning, tested by training bees to different odours, provides a useful model of other phenomenon important in learning theory, such as overshadowing, blocking, massed and spaced training effects, and habituation. The research also indicates a circadian rhythm in the olfactory learning, which is linked to the field, where food sources are only available during certain periods of the day. A new technique was developed to investigate long term captivity and the effects this has on olfactory learning and homing abilities. In both these different, but crucial, learning criteria, captivity played no significant effect, suggesting that the long term memory of the honeybee is a stable, and not easily disrupted entity. The behavioural and developmental stages of the dynamic honeybee colony were examined, to identify any differences in learning in bees aged 1-24 days old. Bees younger than 15 days of age did not show comparable learning to adult foragers, despite having a fully mature olfactory neural pathway. Similarly, PER learning of different castes was researched, with nurse, guard, forager, and precocial forager bees being studied. The results showed that there exists a heirachy in olfactory learning with nurse and guard bees exhibiting learning lower than foragers and precocious foragers. This suggests the social role of the bee, and the interaction between behavioural maturation within its complex society, is a major determinant of olfactory learning ability. The effects of the season are also examined to see if the levels oflearning are constant over the year. Learning was reduced in the summer months, with an increased learning in the winter, which is related to the available forage and the hive demography. The experiments reported show that by using just one example of bee learning, insights into the mechanisms oflearning and memory can be sought. The olfactory system of the honey bee is particularly well researched, and thus, bees can be easily used as a tool at all levels of enquiry from molecular and cellular studies to behavioural genetics, anatomy and physiology

How does our ability to integrate information across space and time change as we age?

This thesis investigated the nature of changes in feature binding ability that occur as a function of healthy ageing. Under the premise that these changes may occur due to reduced attentional resources (Sylvain-Roy et al., 2005), or changes in the ability to use contextual information as cue for recall (Meulenbroek et al., 2010), two hypotheses were tested; the ageing-attention hypothesis, and the ageing-context hypothesis. These hypotheses were tested under intentional binding instructions (e.g. Allen et al., 2006), and incidental binding instructions (e.g. Campo et al., 2010) which also included tests of whether nearby contextual information or absolute location are used in location binding (e.g. Olson & Marshuetz, 2005). The thesis found no support for either the ageing-attention hypothesis or the ageing-context hypothesis. The most valuable findings were the effortful nature of younger adult incidental location binding, and perhaps more crucially, the demonstration that older adult binding deficits may be best explained in terms of inhibitory deficit and differences in processing style between older and younger adults

Comparison of T-cell Receptor Diversity of people with Myalgic Encephalomyelitis versus controls

Objective: Myalgic Encephalomyelitis (ME; sometimes referred to as Chronic Fatigue Syndrome) is a chronic disease without laboratory test, detailed aetiological understanding or effective therapy. Its symptoms are diverse, but it is distinguished from other fatiguing illnesses by the experience of post-exertional malaise, the worsening of symptoms even after minor physical or mental exertion. Its frequent onset after infection suggests autoimmune involvement or that it arises from abnormal T-cell activation. Results: To test this hypothesis, we sequenced the genomic loci of and T-cell receptors (TCR) from 40 human blood samples from each of four groups: severely affected people with ME; mildly or moderately affected people with ME; people diagnosed with Multiple Sclerosis, as disease controls; and, healthy controls. Seeking to automatically classify these individuals’ samples by their TCR repertoires, we applied P-SVM, a machine learning method. However, despite working well on a simulated data set, this approach did not allow statistically significant partitioning of samples into the four subgroups. Our findings do not support the hypothesis that blood samples from people with ME frequently contain altered T-cell receptor diversity

2003 Fine Art Graduation Exhibition Catalogue

BODY Graduation ExhibitionFanshawe College Fine Art Program 2003 April 11th - 27th McIntosh GalleryUniversity of Western Ontario, London, ON Guest Speaker: Jane Buyershttps://first.fanshawec.ca/famd_design_fineart_gradcatalogues/1024/thumbnail.jp

Developmental changes in the engagement of episodic retrieval processes and their relationship with working memory during the period of middle childhood.

We examined the development of children’s engagement of the episodic retrieval processes of recollection and familiarity and their relationship with working memory (WM). Ninety-six children (24 in four groups aged 8, 9, 10, and 11 years) and 24 adults performed an episodic memory (EM) task involving old/new, remember/know (R/K), and source memory judgements and numerous WM tasks that assessed verbal and spatial components of WM and delayed short-term memory (STM). Developmental changes were observed in EM with younger children (8-, 9-, 10-year-olds) making fewer remember responses than 11-year-olds and adults while 11-year-olds did not differ from adults. Only children aged 10 years plus showed a relationship between EM and WM. EM was related to verbal executive WM in 10- and 11-year-old children suggesting that children at this stage use verbal strategies to aid EM. In contrast, EM was related to spatial executive WM in adults. The engagement of episodic retrieval processes appears to be selectively related to executive components of verbal and spatial WM, the pattern of which differs in children and adults

Hexapeptides from mammalian inhibitory hormone hunt activate and inactivate nematode reproduction

© 2022 Hart et al. This is an open access article distributed under the terms of the Creative Commons Attribution License. https://creativecommons.org/licenses/by/4.0/Background: Biopurification has been used to disclose an evolutionarily conserved inhibitory reproductive hormone involved in tissue mass determination. A (rat) bioassay-guided physicochemical fractionation using ovine materials yielded via Edman degradation a 14-residue amino acid (aa) sequence. As a 14mer synthetic peptide (EPL001) this displayed antiproliferative and reproduction-modulating activity, while representing only a part of the native polypeptide. Even more unexpectedly, a scrambled-sequence control peptide (EPL030) did likewise. Methods: Reproduction has been investigated in the nematode Steinernema siamkayai, using a fermentation system supplemented with different concentrations of exogenous hexapeptides. Peptide structure-activity relationships have also been studied using prostate cancer and other mammalian cells in vitro, with peptides in solution or immobilized, and via the use of mammalian assays in vivo and through molecular modelling. Results: Reproduction increased (x3) in the entomopathogenic nematode Steinernema siamkayai after exposure to one synthetic peptide (IEPVFT), while fecundity was reduced (x0.5) after exposure to another (KLKMNG), both effects being dose-dependent. These hexamers are opposite ends of the synthetic peptide KLKMNGKNIEPVFT (EPL030). Bioactivity is unexpected as EPL030 is a control compound, based on a scrambled sequence of the test peptide MKPLTGKVKEFNNI (EPL001). EPL030 and EPL001 are both bioinformatically obscure, having no convincing matches to aa sequences in the protein databases. EPL001 has antiproliferative effects on human prostate cancer cells and rat bone marrow cells in vitro. Intracerebroventricular infusion of EPL001 in sheep was associated with elevated growth hormone in peripheral blood and reduced prolactin. The highly dissimilar EPL001 and EPL030 nonetheless have the foregoing biological effects in common in mammalian systems, while being divergently pro- and anti-fecundity respectively in the nematode Caenorhabditis elegans. Peptides up to a 20mer have also been shown to inhibit the proliferation of human cancer and other mammalian cells in vitro, with reproductive upregulation demonstrated previously in fish and frogs, as well as nematodes. EPL001 encodes the sheep neuroendocrine prohormone secretogranin II (sSgII), as deduced on the basis of immunoprecipitation using an anti-EPL001 antibody, with bespoke bioinformatics. Six sSgII residues are key to EPL001’s bioactivity: MKPLTGKVKEFNNI. A stereospecific bimodular tri-residue signature is described involving simultaneous accessibility for binding of the side chains of two specific trios of amino acids, MKP & VFN. An evolutionarily conserved receptor is conceptualised having dimeric binding sites, each with ligand-matching bimodular stereocentres. The bioactivity of the 14mer control peptide EPL030 and its hexapeptide progeny is due to the fortuitous assembly of subsets of the novel hormonal motif, MKPVFN, a default reproductive and tissue-building OFF signal.Peer reviewe

Emotional cues enhance the attentional effects on spatial and temporal resolution

In the present study, we demonstrated that the emotional significance of a spatial cue enhances the effect of covert attention on spatial and temporal resolution (i.e., our ability to discriminate small spatial details and fast temporal flicker). Our results indicated that fearful face cues, as compared with neutral face cues, enhanced the attentional benefits in spatial resolution but also enhanced the attentional deficits in temporal resolution. Furthermore, we observed that the overall magnitudes of individuals’ attentional effects correlated strongly with the magnitude of the emotion × attention interaction effect. Combined, these findings provide strong support for the idea that emotion enhances the strength of a cue’s attentional response

The Skin of Spectral Time in Grisey's Le Noir de l’Étoile

Following the aesthetics of pure continuity in the late 1970s, Grisey moved on to compose for unpitched percussion in Tempus ex Machina, focusing on pure rhythm. Shortly afterwards he elaborated on his theory of temporality in a talk and article of the same title; one decade later, he included Tempus as the first movement of Le Noir de l’Étoile. Grisey insisted on the significance of the perception of musical time, of the skin of time – as opposed to its skeleton or flesh. This article puts forward an interpretation of Grisey's thinking of temporality, drawing on concepts from French philosophy. It further provides an analysis of two sections of Le Noir, tracing these concepts in the structuring of musical time, with a view to providing a possible direction towards a re-definition of spectral time

Violation of the 12/23 rule of genomic V(D)J recombination is common in lymphocytes

V(D)J genomic recombination joins single gene segments to encode an extensive repertoire of antigen receptor specificities in T and B lymphocytes. This process initiates with double-stranded breaks adjacent to conserved recombination signal sequences that contain either 12- or 23-nucleotide spacer regions. Only recombination between signal sequences with unequal spacers results in productive coding genes, a phenomenon known as the '12/23 rule.' Here we present two novel genomic tools that allow the capture and analysis of immune locus rearrangements from whole thymic and splenic tissues using second-generation sequencing. Further, we provide strong evidence that the 12/23 rule of genomic recombination is frequently violated under physiological conditions, resulting in unanticipated hybrid recombinations in ∼10% of Tcra excision circles. Hence, we demonstrate that strict adherence to the 12/23 rule is intrinsic neither to recombination signal sequences nor to the catalytic process of recombination and propose that nonclassical excision circles are liberated during the formation of antigen receptor diversity

Deuxième quatuor à cordes

« Il s’agit dans ce morceau de silence — non pas du silence littéral (bien que ceci soit également un trait caractéristique évident de la section d’ouverture) mais plutôt de cette absence délibérée au cœur de l’expérience musicale qui existe afin que l’auditeur puisse s’y rencontrer. Puisqu’il n’est possible d’approcher les différentes formes de silence que par le biais de leurs divers négatifs propres, l’organisation de ce quatuor s’efforce de définir plusieurs chemins concentriques de plus ..