Surfactants and Thickeners are both additives used in fully-formulated waterborne coatings to provide colloidal stability, thickening, and other functionality. The behavior of each ingredient in a coating must be understood and controlled to maintain colloidal stability as well as balance other desired properties of the liquid coating and the dry paint film. In this work, quaternary systems of Water-Latex-Thickener-Surfactant were investigated to further the understanding of their behavior in coatings. The thickener used was a well characterized, hydrophobically-modified, ethoxylated urethane (HEUR) with two C18 terminal hydrophobes and 795 average repeat units of ethylene oxide as the hydrophilic spacer. Two latexes, a hydrophobic butyl acrylate/styrene and a hydrophilic butyl acrylate/methyl methacrylate, each containing a small amount of methacrylic acid monomer were used. Six different surfactants, three non-ionic and three-anionic, were used. By maintaining the concentrations of latex and HEUR thickener as constants and varying the surfactant concentration, effects of the surfactant loading on rheology were determined. As concentration of surfactant increases, a characteristic shear-thickening maximum associated with bridging of latex particles by the HEUR thickener was seen to shift to higher shear rates; surfactants at all concentrations studied, except SDS, lowered the viscosities within the low shear rate region. Dynamic viscoelastic measurements shed further light into the behavior of the mixtures. The results will be explained based on surfactant and latex surface polarities and the competitive adsorption between the v surfactant and HEUR hydrophobes, and other interactions between surfactants and thickeners.

<div>While cognitive control enables the selection of goal-relevant responses, metacontrol enables the selection of context-appropriate control operations. In task switching, metacontrol modulates task-switching efficiency by retrieving the associations between a contextual cue and a particular cognitive control demand. While the automatic retrieval of cognitive control is appealing due to its time and energy efficiency, the effects of different contextual cues have been shown in separate studies and appear to have different characteristics. Here, we devised a single task-switching paradigm to test whether we can observe both list-wide and item-specific metacontrol within subjects. In two experiments, we demonstrated reduced switch costs in lists associated with a high probability of switching as compared with lists with a low probability of switching (i.e., a list-wide switch probability [LWSP] effect). Similarly, we observed an analogous item-specific switch probability (ISSP) effect such that items associated with a high probability of switching incurred smaller switch costs as compared with items associated with a low probability of switching. We also confirmed that both list-wide and item-specific switch probability effects were not dependent on lower-level stimulus-response associations. However, the LWSP and the ISSP effects were uncorrelated, suggesting a lack of dependence. Together, these findings suggest that there are two distinct modes of metacontrol that are deployed in a context-sensitive manner in order to adapt to specific cognitive demands.</div>

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A B S T R A C T Presented work focuses on experimental study of anion interaction with neutral particles at temperatures relevant for astrophysics. Anion H− , important for molecular hydrogen creation, and O− as a possible source of water are investigated. The temperature dependence of reac- tion rate coefficients from 10 to 150 K for reactions H− + H → H2 + e− and O− + H2 → H2O + e− has been determined. The energy distri- bution of electrons produced in the latter reaction at 300 K has also been acquired. These studies have been performed on two experimen- tal setups, which are presented together with the theory of operation, construction details, calibration, and supporting test measurements.

Cognition allows animals to acquire, process, and store sensory information from the environment and use it to adapt to their surroundings. A battery of behavioral tests was used to assess the cognitive abilities of black-handed spider monkeys (Ateles geoffroyi). Black and white cups were used to assess (1) object permanence by showing the animals under which cup the reward was placed, (2) associative learning by concealing where the reward was placed, and (3) long-term memory by repeating the second task after a 4-month break; petri dishes with varying amounts of food were used to assess (4) relative quantity discrimination; and boxes fitted with dotted cards were used to assess discrete number discrimination with (5) equallysized dots and (6) various-sized dots. For each task, one session comprised 10 trials (i.e. responses). All nine animals succeeded in all tests and, as a group, reached the learning criterion of 70% correct responses on session two in the object permanence and associative learning tasks; on session eleven in the quantity discrimination task; on session sixteen in the numerosity task with equally-sized dots; on session three in the numerosity task with various-sized dots; and averaged 84.4% correct responses in the long-term memory task. Their prompt high score in the numerosity task with various-sized dots suggests that the animals acknowledged the task for its numerical properties as opposed to the size or pattern of the dots. These cognitive abilities are thought to shape the necessary behaviors for the ecological and social needs of the species.

Introduction and background: Family-centred care in the intensive care unit has increased steadily over the past three decades, based on the premise that the illness and health of an individual family member affects the whole family unit. Although widely researched there are still inconsistencies in implementing family-centred care, which influences the ability to transfer research findings into practice. Research has shown that recognising the role of family members in the critical care environment should be considered an essential component to caring for the critically ill patient. Although recommendations have been made for the implementation of familycentred care, it is not feasible for all recommendations to be adopted by nurses and healthcare professionals in a single ICU. Nurses and healthcare professionals need to customise strategies to an individual intensive care unit to improve family-centred care. Aim: The aim of the study was to explore and describe nurses, healthcare professionals and family members’ perceptions of family-centred care in the intensive care unit. Research design and methods: A quali-quanti research design was used. Participants included nurses, healthcare professionals and family members in the intensive care unit of a private hospital in Gauteng, South Africa. There were a total of sixty (60) participants who took part in the study. Nurses were selected using stratified random sampling, healthcare professionals were selected using total population sampling and family members were selected using purposive, maximum variation and convenience sampling. Data was collected over a period of one month by means of structured interviews using an associative group analysis technique. Participants were asked to write down free word associations in relation to the stimulus word “family-centred care” in order to explore and describe their perceptions of family-centred care in the intensive care unit as it is currently, as it could be in the “ideal world” and any gaps that exist around these perceptions. Results: Five themes were derived from the data: communication, environment, continuum of feelings, reflections and spiritual care. Conclusion: The implementation of family-centred care should involve all stakeholders in the intensive care unit in order to address inconsistencies in perceptions around family-centred care. Keywords: Associative group analysis, intensive care unit, family-centred care, healthcare professionals, nurses, perceptions, stakeholders / Dissertation (MNur)--University of Pretoria, 2019. / Nursing Science / MNur (Clinical) / Unrestricted

This research investigates developing a training method for Restricted Hopfield Network (RHN) which is a subcategory of Hopfield Networks. Hopfield Networks are recurrent neural networks proposed in 1982 by John Hopfield. They are useful for different applications such as pattern restoration, pattern completion/generalization, and pattern association. In this study, we propose an enhanced training method for RHN which not only improves the convergence of the training sub-routine, but also is shown to enhance the learning capability of the network. Particularly, after describing the architecture/components of the model, we propose a modified variant of SPSA which in conjunction with back-propagation over time result in a training algorithm with an enhanced convergence for RHN. The trained network is also shown to achieve a better memory recall in the presence of noisy/distorted input. We perform several experiments, using various datasets, to verify the convergence of the training sub-routine, evaluate the impact of different parameters of the model, and compare the performance of the trained RHN in recreating distorted input patterns compared to conventional RBM and Hopfield network and other training methods.

<div><div><div><p>The brain dynamically alters its production of flexible behavior: cognitive flexibility increases when demand is high. In task switching experiments, past exposure to a high demand for flexibility in conjunction with specific temporal contexts leads to learned switch readiness such that future exposures to those contexts will cue flexibility. According to a recent proposal (Dreisbach & Fröber, 2019), learned switch readiness following switch demands is supported by a concurrent activation (CA) cognitive mechanism whereby both sets of task rules are kept available in working memory despite only using one at a time. This can be differentiated from a competing candidate mechanism, working memory updating (WMU) thresholds which determine the ease of replacing one task’s rules with another. The WMU mechanism is expected to cause a global increase in flexibility while CA is conceptualized as limited to task-specific associations. To test whether learned switch readiness represents a global or limited change in the cognitive system, I conducted two experiments that both involved learning switch readiness in one context and generalizing it in another. In Experiment 1, I replicated and extended findings that switch probability manipulations can modulate voluntary switch rates (VSR), indicating one type of generalizability. However, in Experiment 2, I found that flexibility learned through switch probability manipulations did not transfer to new tasks when the task rules were changed but contextual cues remained the same, demonstrating a limit: learned switch readiness does not generalize across tasks. These findings together suggest that CA is likely the mechanism behind learned switch readiness.</p></div></div></div>

This study evaluated four lactic streptococcal pairs which had been used routinely in cheese plants to determine (1) if strain growth interactions would produce stimulated growth and acid production; (2) final percent strain ratios and generation times after 1/1 initial inocula volumes and (3) whether final strain ratios could be controlled through adjustment of initial inocula volumes. Strains were propagated in fortified and unmodified whey substrate under pH control at 27C for 12 hours. Cell number and acid activity were evaluated on single and paired strains. Phage typing was used to determine generation times and the percent of each strain in a pair. Cell number increase was found in two of the four pairs grown in the unmodified whey substrate but in only one of the four pairs grown in the fortified medium. Acid production increase was observed in one pair when grown in the unmodified whey substrate, and in one other pair when grown in the fortified medium. Final strain percent ratios of the two of the four pairs (with initial inocula of a 1/1, v/v, ratio), demonstrated unbalanced growth, with one strain accounting for 76 to 92% of the final flora. Generation times of the dominant strain varied significantly with incocula ratios. Increasing the inocula volume ratio of the dominated strain of one pair from 1/1 to 19/1 dropped the final percent of the dominant strain from an average value of 83 to 66%. The dominant organism of this pair increased its doubling time when the inocula ratio was varied from 3/1 to 19/1 (dominated/dominant).

Toutes les informations présentes actuellement sur le web représentent une source d‘informations colossale, qui s‘enrichit de jour en jour. L‘analyse automatique de ces informations, qui sont plus souvent non-structurées, constitue un véritable enjeu économique et scientifique. La résolution des anaphores nominales s‘inscrit dans la structuration des informations grâce à l‘identification du lien entre des groupes nominaux, elle permet de simplifier des tâches à différentes applications : la traduction automatique, le résumé ou l‘extraction automatique d‘information, le data mining etc. Dans ce contexte, le travail que nous avons mené dans cette thèse évoque différentes méthodes de résolution des anaphores nominales de deux types : infidèles et associatives. En nous fondant sur divers aspects autours de la notion d‘anaphore nominale et des notions de voisinage comme la résolution d‘anaphores pronominales, la résolution de coréférences ; en combinant des méthodes existantes avec des outils et des ressources disponibles pour la langue française, notre travail s‘attache à trois modules : module de prétraitement du corpus, module de résolution des anaphores nominales et le module d‘évaluation. Au module de prétraitement, les ressources lexicales sont constituées et mobilisées grâces aux analyses au niveau linguistique des anaphores nominales. La plateforme Unitex est le principal outil utilisé à cette étape. Pour les anaphores du type infidèle, nous avons utilisé deux méthodes différentes : la première mobilise des ressources lexicales simples avec les entrées de groupes nominaux uniquement ; la deuxième mobilise des ressources plus élaborées (les entrées de groupes nominaux et verbaux). Pour les anaphores associatives du type méronymique, nous nous fondons sur la théorie des classes d‘objets afin de décrire le type de relation anaphorique établie Résumé 17 entre l‘expression anaphorique et son antécédent. Les ressources utilisées pour ce type d‘anaphore sont ainsi divisées hiérarchiquement selon les classes et les domaines. Le module de résolution est l‘étape de décision, nous nous basons sur le calcul du poids de saillance de chacun des antécédents potentiels pour sélectionner le meilleur candidat. Chaque candidat peut avoir différents facteurs de saillance, qui correspond à sa probabilité d'être sélectionné. Le poids de saillance final est calculé par le moyen pondéré des poids de saillance élémentaires. Les facteurs de saillances sont proposés après les analyses syntaxiques et sémantiques du corpus. L‘évaluation de notre travail constitue un vrai enjeu à cause de la complexité de la tâche, mais elle nous permet d‘avoir une vue globale sur nos méthodes de travail. La comparaison des résultats obtenus permet de visualiser l‘apport de chaque paramètre utilisé. L‘évaluation de notre travail nous permet également de voir les erreurs au niveau du prétraitement (l‘extraction des syntagmes nominaux, des syntagmes verbaux…), cela nous a permis d‘intégrer un module de correction dans notre système. / In order to facilitate the interpretation of texts, this thesis is devoted to the development of a system to identify and resolve the indirect nominal anaphora and the associative anaphora. Resolution of the indirect nominal anaphora is based on calculating salience weights of candidate antecedents with the purpose of associating these antecedents with the anaphoric expressions identified. It is processed by twoAnnexe317different methods based on a linguistic approach: the first method uses lexical and morphological parameters; the second method uses morphological and syntactical parameters. The resolution of associative anaphora is based on syntactical and semantic parameters.The results obtained are encouraging: 90.6% for the indirect anaphora resolution with the first method, 75.7% for the indirect anaphora resolution with the second method and 68.7% for the associative anaphora resolution. These results show the contribution of each parameter used and the utility of this system in the automatic interpretation of the texts.