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Approximating Solutions to Convection-Diffusion Equations by Tensor Train Decompositions
Get PDFA finite volume method for solving general time-homogeneous convection-diffusion equations with zero source term is presented. Computational efficiency of the method is improved by performing linear algebra in the tensor train format. To our knowledge this is the first time that the tensor train format and the finite volume method have been combined for this purpose.
Finite volume methods, tensors and tensor decompositions are reviewed by summarising prominent texts on each respective topic. We extend a finite volume method for convection equations to include diffusion terms and show that the method preserves integrals and positivity. The time discretisation uses an explicit Euler step that leads to a sequence of linear systems of equations defining a discrete approximation of the solution at some final time. The recurrence is stepped forwards in time by performing algebraic operations in the tensor train format. In some cases, this leads to a significant increase in computational efficiency.
We use our tensor train implementation of the finite volume method to approximate the allele frequency spectrum in three populations by solving the Wright-Fisher diffusion equation. Our method did not appear to outperform current methods for approximating the allele frequency spectrum. However, we develop some interesting and efficient tools for approximating the allele frequency spectrum if the solution to the Wright-Fisher diffusion equation is known in tensor train format
Registered Nurses experiences, knowledge and practice of kangaroo care for preterm babies in two Neonatal Intensive care units in South Island of New Zealand
Get PDFInternational research acknowledges that there are multi-dimensional factors that affect the implementation of kangaroo care in the neonatal intensive care unit. While it is accepted that the nurse plays an important role in stimulating the implementation of kangaroo care, its success as a neonatal care strategy pivots on infant readiness, parental readiness and parental availability. In addition, interprofessional collaboration and teamwork are necessary for safe implementation. Kangaroo care is a simple and cost-effective health strategy that has well documented effects for its contribution towards improving well-being and health outcomes for premature babies and their parents. Its benefits when applied to preterm babies in the neonatal intensive care are immediate and cumulative. Importantly research has shown that the benefits and implications of kangaroo care for health go beyond the neonatal intensive care.
However, little is known about New Zealand registered nurses’: experiences of their role in the implementation of kangaroo care; knowledge of the underpinning evidence supporting the therapeutic value of kangaroo care for premature babies; and current level of practice of kangaroo care.
Aim: The aim of this study was to explore registered nurses’ experiences, knowledge and practice of kangaroo care and to highlight factors that promote or hinder the uptake of kangaroo care for preterm babies in two neonatal intensive care units in New Zealand.
Methods: Using a purposive sampling strategy, 14 registered nurses, who met the inclusion criteria, participated. This was a qualitative, semi-structured interview-based study. The participants guided the flow of the interviews. Inductive thematic analysis, as outlined by Braun and Clarke, allowed for rich-description and interpretation of the participant-generated meanings. Coded data was grouped into themes and sub-themes.
Results: Four main themes were generated from the data. Importantly the findings from this study highlighted that nurses in New Zealand know about kangaroo care and use it in everyday clinical practice. The snapshots of clinical practice provided by the nurses strengthened what is known about the effects of kangaroo care on the baby and the parents. The nurses made it apparent that applying kangaroo care was implicit in the ICU when babies were most likely to be at a critical phase in their development and recovery.
Most of the nurses named the lack of standardisation of practice and out-dated nursing practice mind-sets as influential to the variable implementation of daily kangaroo care for the growing preterm baby. Half of the nurses highlighted that staffing, heavy workloads, the busy, crowded, and noisy environment of less acute areas were influential to the limited practice of kangaroo care for stable growing preterm babies.
Conclusion: This study identified organisational support for the practice of kangaroo care in the neonatal intensive care unit. Also, that kangaroo care was being implemented, albeit irregularly. It established that facilitating parental readiness, affording clear local practice guidelines, providing continuing education initiatives for staff as well as parents may invigorate the practice of kangaroo care within the neonatal intensive care unit
The Role of Personality in Daily Food Allergy Experiences
Get PDFFood allergies present numerous challenges to coping in everyday life. Even simple things like planning a lunch with a friend can be stressful for people with food allergies. But are some people more adversely impacted by having a food allergy than other people? This paper addressed this question by investigating whether individual differences in the Big Five personality traits (neuroticism, extraversion, openness, agreeableness, and conscientiousness) are related to food allergy-related problems in everyday life among adults with food allergies. Participants were 108 adults (85% female; mean age = 40.2; age range 18–87) with a physician-diagnosed food allergy [most commonly to gluten (54.6%), peanuts (21.3%), cow’s milk (16.7%), and shellfish/seafood (16.7%)]. Participants completed an initial online survey that measured demographics, food allergy information, and personality traits using the Big Five Inventory (John et al., 1991). For 2 weeks, participants completed a daily online survey that queried the occurrence of 25 food allergy issues that day and participants’ overall stress and mood that day. Neuroticism did not predict more frequent allergy issues or greater stress/poorer mood on days with more allergy issues. Instead, higher openness to experience predicted a range of issues including going hungry because there is no safe food available, problems finding suitable foods when grocery shopping, feeling anxious at social occasions involving food, being excluded, and feeling embarrassed and poorly understood about their food allergy. Conscientious people were less embarrassed or self-conscious about their food allergy, but they had more problems eating out, and their positive mood was more impaired by allergy issues than their less conscientious peers. Extraversion and agreeableness played minor roles. Personality testing can identify people that may have difficulty living with food allergies–such as those higher in openness to experience
The role of emotions in the experiences of commercial high-altitude mountaineering guides who have guided above the death-zone
No full textThe body of tour guiding research has identified the importance of emotions and emotion management to guide’s experiences. However, there is a far less granular understanding of why, when, and how at each stage of a trip emotions change guide experiences. To date, studies of guides’ emotions have treated an entire experience as a single point of time, and do not provide a coherent picture of how emotions change guide experiences over the course of a trip. This generalised approach has hampered the dynamic and full interpretation of emotions in guides’ experience because emotions have different sets of appraisals, and each emotion of the same valence differs in their influence on people’s experiences over time. Therefore, a deeper insight into how emotions change an actual experience at the moment, as the guiding trip unfolds, is essential to optimising the overall guide’s experiences. This study seeks to fill these gaps by exploring the role of emotions in the experiences of commercial high-altitude mountaineering guides working above the death zone (i.e. over 8,000 meters). The work of commercial high-altitude mountaineering guides (HAMGs), which incorporates expeditions lasting for more than six weeks, provides an opportunity to analyse how emotions change participants’ experiences. This starts with the planning and preparation for the expedition, runs through the actual trip, and incorporates a post-expedition period. All these stages are associated with stress, pressure, and responsibilities to perform the day-to-day tasks that differ substantially across the experience.
Data collection was undertaken in Kathmandu, Nepal, where the researcher spent 90 days interviewing (online and in-person) commercial high-altitude mountaineering guides (16 participants: seven female and nine male) from eight countries. Thematic analysis was used to explore how emotions change HAMGs’ experiences across the expedition.
Focusing on high-altitude mountaineering guiding, the findings revealed that emotions play a key role in all three main phases of the HAMGs experience. At the pre-guiding stage, the themes individual reasons, social influences, occupational difficulties, and occupational opportunities link to elicited emotions. During the expedition, the experiences of emotions varies in intensity from the time when the expedition team meet in the base camp, throughout the climb, and until the team returns to the base camp safely. In the post-guiding phase, the themes occupational barriers, social influences, and individual reasons represent the complex role of emotions in participants’ experiences. The discussion is bounded by various reasons to continue and discontinue guiding. All of these phases demonstrate how emotions change commercial high-altitude mountaineering guides overall experiences.
This study expands the tour guiding, hospitality and emotional labour literature by: (1) providing a coherent picture of how emotions change guides experiences throughout participation; (2) shedding light on the working reality of frontline service employee experiences influenced by emotions; (3) suggesting that commercial high-altitude mountaineering guides perform emotion management acts at every stage of the expedition; (4) translating the findings into recommended practices for mountaineering tourism expedition operators and mountaineering guiding associations
Effect of information on Chinese consumers’ perceptions and purchase intention for beverages processed by High Pressure Processing, Pulsed-Electric Field and Heat Treatment
Get PDFHigh Pressure Processing (HPP) and Pulsed-Electric Field (PEF) are non-thermal technologies that add value to foods by improving safety through lowering microbial loads in addition to improving the sensory properties such as color, flavor, and texture. While Heat Treatment (HT) is more widely accepted by consumers, it is a more destructive process compared to HPP and PEF. Little is known about how Chinese consumers perceive non-thermal technologies like HPP and PEF. This research aimed to understand Chinese consumer’s perceptions of non-thermal processing technologies and ways to mitigate negative perceptions. Specifically, this research sought to investigate: (a) consumers’ general knowledge of food processing technologies; (b) the effect of information on consumers’ perceptions of HT, HPP and PEF and how these perceptions influence decisions for their treated beverages; and (c) consumers’ willing-ness to pay for products processed using these technologies. Six focus groups were conducted in Hangzhou, China. When participants were provided limited and detailed technology information, six dominant consumer perceptions towards HT, HPP, and PEF emerged. Those perceptions were: (1) consumer association with the given technology, (2) trust towards the technology, (3) health, (4) food, (5) taste and quality, and (6) price. When limited information was provided, consumers were skeptical of HPP and PEF. However, the provision of detailed technology information changed participants’ attitudes towards HPP and PEF technologies and increased their stated purchase intentions for the treated products. Participants were also found to place less emphasis on the price for HPP and PEF treated beverages when detailed technology information was provided. Chinese consumers were interested in having fewer additives in their foods. Non-thermally processed foods offer this benefit. Given the change in attitudes after receiving detailed information, HPP and PEF processing technologies have potential to be widely accepted by Chinese consumers. However, to effectively promote these technologies, consumer education is needed to increase awareness of the advantages these technologies have for foods. Practical communication strategies are provided to help food manufacturers inform Chinese consumers about the benefits of these technologies
FICare in a New Zealand NICU
No full textBackground
Family integrated care (FICare) is a model of care which shifts the role of parents from ‘observers’ of their infant’s care to being their infant’s ‘primary caregiver’ in Neonatal Intensive Care Units (NICU). One NICU in the South Island of New Zealand (SI-NZ) implemented FICare after being involved in an international randomised controlled trial (RCT) comparing FICare with standard NICU care. FICare’s model comprises four pillars previously identified as necessary for implementation: 1) Staff education and support, 2) Parent education, 3) NICU environment and resources, and 4) Psychosocial support. The RCT found FICare improved infant weight gain and breastfeeding rates and decreased hospital acquired infections and parental stress. However, alongside trial findings there is a need for qualitative research to inform the effective implementation of FICare – and specifically in New Zealand (NZ).
Aim
To qualitatively understand the experience of providing and receiving care via the FICare model from the perspectives of NICU staff, parents and whānau.
Methods
Group and individual interviews were used to collect data about staff experiences delivering FICare; serial interviews were used for parents’/whānau experiences. Two interviews were undertaken with parents/whānau: 1) during their NICU admission, and 2) six to twelve weeks post-NICU discharge. Interviews were audio-recorded, transcribed verbatim and analysed thematically.
Results
Thirteen multidisciplinary NICU staff were interviewed; there were six parent/whānau first interviews in NICU, and five post-discharge. Staff identified that differences in staff FICare education affected FICare delivery with some receiving more robust education than others. Although providing culturally responsive care is not specified within the FICare model, many staff reported that FICare’s principles aligned well with those of the Treaty of Waitangi. Parent/whānau interviewees reported inconsistencies in care between participants who were able to stay in NICU with their infants and those who could not. Participants who stayed in NICU described experiences of receiving care closely aligned with FICare, such as actions guided by the pillars of Parent education, NICU environment and resources, and Psychosocial support. Parents unable to stay in NICU (e.g. due to work, other child commitments or availability of parent beds), were less likely to report care aligned with the FICare model. Participants staying in NICU reported culturally responsive care and greater satisfaction with parent-staff relationships, parent-infant engagement and trust with staff, compared to those who did not.
Conclusion
Findings led to development of an adapted FICare model – potentially more appropriate for NZ. Future testing of this adapted model (named ‘FICare-NZ’) by other researchers is welcomed. Key aspects of FICare-NZ include the importance of culturally responsive care. Additionally, for successful FICare implementation it is recommended that all staff receive consistent FICare education. Therefore, FICare-NZ can be depicted with ‘Staff education’ becoming a foundational step supporting the other three pillars; with a second, and equally critical, foundational step being added for ‘Culturally responsive care’. FICare-NZ therefore comprises these two steps leading up to three (original FICare) pillars: 1) ‘Parent education’, 2) ‘NICU environment and resources’, and 3) ‘Psychosocial support’. Finally, FICare-NZ proposes a canopy layer on top of the pillars to represent the importance of ‘Parents’ experiences of NICU admission’
Prioritisation of requests, bugs and enhancements pertaining to apps for remedial actions. Towards solving the problem of which app concerns to address initially for app developers
Get PDFUseful app reviews contain information related to the bugs reported by the app’s end-users along with the requests or enhancements (i.e., suggestions for improvement) pertaining to the app. App developers expend exhaustive manual efforts towards the identification of numerous useful reviews from a vast pool of reviews and converting such useful reviews into actionable knowledge by means of prioritisation. By doing so, app developers can resolve the critical bugs and simultaneously address the prominent requests or enhancements in short intervals of apps’ maintenance and evolution cycles. That said, the manual efforts towards the identification and prioritisation of useful reviews have limitations. The most common limitations are: high cognitive load required to perform manual analysis, lack of scalability associated with limited human resources to process voluminous reviews, extensive time requirements and error-proneness related to the manual efforts. While prior work from the app domain have proposed prioritisation approaches to convert reviews pertaining to an app into actionable knowledge, these studies have limitations and lack benchmarking of the prioritisation performance. Thus, the problem to prioritise numerous useful reviews still persists. In this study, initially, we conducted a systematic mapping study of the requirements prioritisation domain to explore the knowledge on prioritisation that exists and seek inspiration from the eminent empirical studies to solve the problem related to the prioritisation of numerous useful reviews. Findings of the systematic mapping study inspired us to develop automated approaches for filtering useful reviews, and then to facilitate their subsequent prioritisation. To filter useful reviews, this work developed six variants of the Multinomial Naïve Bayes method. Next, to prioritise the order in which useful reviews should be addressed, we proposed a group-based prioritisation method which initially classified the useful reviews into specific groups using an automatically generated taxonomy, and later prioritised these reviews using a multi-criteria heuristic function. Subsequently, we developed an individual prioritisation method that directly prioritised the useful reviews after filtering using the same multi-criteria heuristic function. Some of the findings of the conducted systematic mapping study not only provided the necessary inspiration towards the development of automated filtering and prioritisation approaches but also revealed crucial dimensions such as accuracy and time that could be utilised to benchmark the performance of a prioritisation method. With regards to the proposed automated filtering approach, we observed that the performance of the Multinomial Naïve Bayes variants varied based on their algorithmic structure and the nature of labelled reviews (i.e., balanced or imbalanced) that were made available for training purposes. The outcome related to the automated taxonomy generation approach for classifying useful review into specific groups showed a substantial match with the manual taxonomy generated from domain knowledge. Finally, we validated the performance of the group-based prioritisation and individual prioritisation methods, where we found that the performance of the individual prioritisation method was superior to that of the group-based prioritisation method when outcomes were assessed for the accuracy and time dimensions. In addition, we performed a full-scale evaluation of the individual prioritisation method which showed promising results. Given the outcomes, it is anticipated that our individual prioritisation method could assist app developers in filtering and prioritising numerous useful reviews to support app maintenance and evolution cycles. Beyond app reviews, the utility of our proposed prioritisation solution can be evaluated on software repositories tracking bugs and requests such as Jira, GitHub and so on
Investigating high light sensitivity in the GT-O2 substrain of Synechocystis sp. PCC 6803
Get PDFThe model organism Synechocystis sp. PCC 6803 (hereafter Synechocystis 6803) has been used for photosynthetic, genomic, proteomic and transcriptomic studies. Recent discoveries of genetic instability in lab strains throughout the world led to the resequencing of the lab strain used in the University of Otago named GT-O1. This lead to the discovery of its substrain GT-O2 that possesses five mutations that were unique from the GT-O1 strain. These mutations were in the chlH, hik8, fadD, htrA and yvcK genes. The GT-O2 strain was unable to acclimatise to prolonged high light periods in comparison to the GT-O1 strain. To elucidate the cause of the high light phenotype, chlH mutant strains (made in the GT-O1 and GT-O2 background) and hik8 mutant strains (made in the GT-O1 background) had been constructed to express either the GT-O1 or GT-O2 copy of the gene of interest. No major high light phenotype was detected in the chlH mutant strains with the exception of a GT-O2 background mutant strain expressing the GT-O1 copy of chlH. This mutant unexpectedly demonstrated severe growth deficiency despite expressing a non-mutated copy of chlH. This suggested the chlH mutation was not solely responsible for the GT-O2 high light phenotype observed but rather a combination of GT-O2 mutations. Under high light, the hik8 mutant strains had shown no differences in growth rates regardless of the copy of hik8 expressed; the hik8 gene was therefore ruled out due to the lack of phenotype. This leaves the fadD, htrA and yvcK genes as the other potential contributors to the high light phenotype. Mutants had been made in a similar fashion to the chlH mutants for the fadD, htrA and yvcK genes in this study. Results from this study demonstrated that the fadD, htrA and yvcK genes were able to confer photoprotection through different mechanisms; the fadD gene affects chl a production and may affect membrane stability; the htrA gene may confer photoprotection through protease activity; the yvcK gene affects carbon metabolism which would upset the balance between photosynthesis and respiration. Along with the chlH and hik8 gene, it paints a picture that all five mutations in GT-O2 strain all contribute to its high light phenotype. Data suggests that the mutations likely occurred to allow the GT-O2 strain to adapt better on a heterotrophic media that it is maintained on. However, these mutations proved disadvantageous in conditions where photoautotrophic growth is required and this would be further exacerbated under high light
Effect of Pregnancy on Forced Exercise in Mice
No full textDuring pregnancy and lactation, a wide range of metabolic changes occur, all of which exist to ensure a healthy pregnancy occurs. One of these reductions is exercise with women typically reducing their exercise levels, even early in pregnancy when there are no physical limitations of the fetus present. In mice, there are rapid reductions in voluntary exercise that occur early in pregnancy with these reductions being caused by the lactogenic hormone, prolactin. How exactly prolactin causes rapid reductions in voluntary exercise during early pregnancy remains unclear. To try and elucidate this phenomenon, we used a forced exercise paradigm in order to test whether prolactin affects the motivation to exercise or the capacity to exercise. Similar to rapid reductions in voluntary exercise, unpublished data has shown mice rapidly reduce their forced exercise capacity in early pregnancy. Recent data from our lab has shown a role for prolactin in acting on reward/motivation circuitry and unpublished data has shown a role for prolactin in thermoregulation. Based on this, the aim of this project was to begin to distinguish between these hypotheses using a forced exercise paradigm that eliminated self-motivation as a factor in exercise during pregnancy and caused increases in body temperature that we attempted to measure using thermal imaging. First, our forebrain prolactin receptor knock-out model was validated using RNAscope in-situ hybridisation with a significant reduction seen in prolactin receptor and GABA neuron colocalization in the medial preoptic area in our knock-out (Prlrlox/loxCamK2aCre) vs control (Prlrlox/lox) mice. Forced exercise capacity remained unchanged during early pregnancy with no observable effect of prolactin on this. Use of a novel peripheral thermal imaging protocol was able to detect changes in exercise-induced and environmental heat change induced changes in tail and eye temperatures. This included detecting differences in thermoregulatory responses to environmental heat change between pregnant and virgin as well as lactating and virgin control mice. The findings of the present study indicate that prolactin might cause previously seen reductions in voluntary exercise during pregnancy through a prolactin-mediated change in the reward/motivation circuitry
Investigation of pelagic food web resilience and potential of biomanipulation techniques to help restore ecological integrity in two eutrophic lakes in New Zealand
No full textLakes are exposed to a wide range of human pressures including invasive species and nutrient enrichment. Restoration of eutrophic lakes is commonly attempted, but many lakes have failed to recover when external nutrient loading is reduced. In such lakes, the manipulation of pelagic food webs to reduce phytoplankton biomass has been useful, resulting in improved water clarity. To devise effective top-down biomanipulation techniques, a combination of long-term and short-term assessments are required. Long-term studies are useful in examining the effects of non-indigenous fish and nutrient enrichment, as these dynamics can take place over several decades. However, intra-annual assessments of fish, zooplankton and phytoplankton communities help in identification of key species, their significant life stages, and the timings of trophic cascades.
I reconstructed the historical pelagic food web structure and dynamics in Lake Hayes and Lake Johnson, both seasonally stratified eutrophic lakes, using palaeolimnological techniques. Then, I correlated these reconstructions with limnological and fisheries records. Results revealed that the study lakes were in a relatively stable, oligotrophic state before the 1940s, and that, contrary to prediction, game fish introduction showed little discernible effect on phytoplankton assemblages and community composition for more than seven decades. The effects of agricultural nutrient enrichment became apparent in the 1940s substantially increasing inferred phytoplankton biomasses. My results also confirmed that the introduced Daphnia pulicaria first established in Lake Hayes in 1972 and in Lake Johnson in 1992, coexisting with the native Daphnia species and leading to an average 2-fold increase in Daphnia spp. abundance. Contrary to prediction, I did not find evidence of a significant increase in grazing pressure on phytoplankton biomass.
I studied phytoplankton and zooplankton communities along with associated physico-chemical variables in Lake Hayes, in the months before and after perch recruitment. My results reveal that in the months following perch recruitment, the zooplankton biomass decreased marginally, and no significant changes in zooplankton community structure were observed, compared with before. However, after perch recruitment, the biomass of the phytoplankton significantly increased, and their compositional variability halved, compared with before. Furthermore, my results suggest that phytoplankton community structure is strongly influenced by the dynamics of Ceratium hirundinella, while zooplankton community structure is strongly influenced by dynamics in Daphnia pulicaria. An inverse association was observed between the biomass of D. pulicaria and that of C. hirundinella both before and after perch spawning, indicating that D. pulicaria had a strong grazing impact, even on the larger phytoplankton taxa which tend to dominate the lake.
I also studied seasonal and ontogenetic dietary and habitat selection shifts in European perch with the aim of gaining understanding of perch interactions with potential pelagic grazers (Daphnia) and water clarity. I used the complementary techniques of gut content analysis and stable isotope (δ13C, δ15N) analysis to quantify the absolute and relative abundance of prey items ingested and assimilated by perch. I predicted that during the summer and autumn after perch recruitment, young-of-the-year (YOY) perch predation would decrease Daphnia abundance, and that this would result in increased chlorophyll a concentration and decreased water clarity. My results suggest that the perch exhibited an extended spawning season, resulting in high abundances of perch larvae in the littoral zone in spring. In summer the abundances of both YOY and adult perch increased substantially in the pelagic zone, while declining in the littoral zone. YOY perch fed primarily on Daphnia and zoobenthos in spring and the early summer. In late summer and autumn both YOY and adult perch mainly fed on Daphnia. Gut content analysis showed that in summer adult perch were cannibalistic, however stable isotope analysis contradicted this, suggesting that zooplanktivory was predominant at that time. In summer and autumn, YOY and adult perch suppressed Daphnia abundance, and this may have decreased herbivory and therefore increased phytoplankton abundance and decreased water clarity.
It appears that the recruitment of perch into zooplanktivorous size classes seems to have induced a trophic cascade. The presence of perch may therefore be an impediment to the restoration of water clarity in Lake Hayes. The use of classical pelagic food web biomanipulation approaches may hence facilitate the restoration of water clarity in this lake and in other similar lakes