Separable time-causal and time-recursive spatio-temporal receptive fields

We present an improved model and theory for time-causal and time-recursive spatio-temporal receptive fields, obtained by a combination of Gaussian receptive fields over the spatial domain and first-order integrators or equivalently truncated exponential filters coupled in cascade over the temporal domain. Compared to previous spatio-temporal scale-space formulations in terms of non-enhancement of local extrema or scale invariance, these receptive fields are based on different scale-space axiomatics over time by ensuring non-creation of new local extrema or zero-crossings with increasing temporal scale. Specifically, extensions are presented about parameterizing the intermediate temporal scale levels, analysing the resulting temporal dynamics and transferring the theory to a discrete implementation in terms of recursive filters over time.Comment: 12 pages, 2 figures, 2 tables. arXiv admin note: substantial text overlap with arXiv:1404.203

Stop worrying; start growing: Risk research on GM crops is a dead parrot: it is time to start reaping the benefits of GM

Opponents of genetically modified crops continue to raise concerns about risk, despite 20 years of research disproving their claims. Science should close the book on risk research and turn to studying the economic and environmental benefits of agricultural biotechnolog

Harnessing ward-level administrative data and expert knowledge to improve staffing decisions: A multi-method case study

© 2019 John Wiley & Sons Ltd Aim: The aim of this study was to investigate the impact of changes to bed configuration and patient mix on nurses’ workload in a single ward. Design: Multi-method case study. Method: The study was undertaken in an acute 28-bed ward in a tertiary referral public hospital in Queensland, Australia. Ward-level administrative data were obtained for a 2-year period, 12 months before bed configuration changes in October 2015 and 12 months after. These data included patient activity (bed occupancy, transfers, length of stay and casemix) and nurse staffing (budgeted and actual staffing levels, employment status and skillmix). Semi-structured interviews were conducted with ward nurses (N = 17) to explore the impact of the bed configuration changes on their workload. Results: Administrative data showed that the bed configuration changes resulted in more complex and dependent patients, increased patient transfers and greater variability in casemix. The interview data found these changes to patient complexity and activity intensified workloads, which were further increased by staffing decisions that resulted in greater reliance on temporary staff. Conclusion: Hospitals already possess the data and expert knowledge needed to improve staffing and bed management decisions without the need for additional, costly workload systems. Impact: Determining appropriate nurse staffing in light of the complexities and variation of patient needs at the ward level remains a challenge. This study identified increases in patient complexity, dependency, variability and churn that increased workload. Staffing grew but hidden factors associated with temporary staffing and skillmix further intensified nurses’ workload. Harnessing existing data and the expertise and experience of nursing unit managers (NUMs) would help staff wards more efficiently and effectively, providing reasonable workloads and appropriate skillmix that can enhance the safety and quality of patient care. To facilitate this, NUMs need access to accurate, timely, data and authority in staffing and bed management decisions

Acute effects of nicotine on visual search tasks in young adult smokers

Rationale Nicotine is known to improve performance on tests involving sustained attention and recent research suggests that nicotine may also improve performance on tests involving the strategic allocation of attention and working memory. Objectives We used measures of accuracy and response latency combined with eye-tracking techniques to examine the effects of nicotine on visual search tasks. Methods In experiment 1 smokers and non-smokers performed pop-out and serial search tasks. In experiment 2, we used a within-subject design and a more demanding search task for multiple targets. In both studies, 2-h abstinent smokers were asked to smoke one of their own cigarettes between baseline and tests. Results In experiment 1, pop-out search times were faster after nicotine, without a loss in accuracy. Similar effects were observed for serial searches, but these were significant only at a trend level. In experiment 2, nicotine facilitated a strategic change in eye movements resulting in a higher proportion of fixations on target letters. If the cigarette was smoked on the first trial (when the task was novel), nicotine additionally reduced the total number of fixations and refixations on all letters in the display. Conclusions Nicotine improves visual search performance by speeding up search time and enabling a better focus of attention on task relevant items. This appears to reflect more efficient inhibition of eye movements towards task irrelevant stimuli, and better active maintenance of task goals. When the task is novel, and therefore more difficult, nicotine lessens the need to refixate previously seen letters, suggesting an improvement in working memory

Considering Intra-individual Genetic Heterogeneity to Understand Biodiversity

In this chapter, I am concerned with the concept of Intra-individual Genetic Hetereogeneity (IGH) and its potential influence on biodiversity estimates. Definitions of biological individuality are often indirectly dependent on genetic sampling -and vice versa. Genetic sampling typically focuses on a particular locus or set of loci, found in the the mitochondrial, chloroplast or nuclear genome. If ecological function or evolutionary individuality can be defined on the level of multiple divergent genomes, as I shall argue is the case in IGH, our current genetic sampling strategies and analytic approaches may miss out on relevant biodiversity. Now that more and more examples of IGH are available, it is becoming possible to investigate the positive and negative effects of IGH on the functioning and evolution of multicellular individuals more systematically. I consider some examples and argue that studying diversity through the lens of IGH facilitates thinking not in terms of units, but in terms of interactions between biological entities. This, in turn, enables a fresh take on the ecological and evolutionary significance of biological diversity

The antisaccade task as an index of sustained goal activation in working memory: modulation by nicotine

The antisaccade task provides a laboratory analogue of situations in which execution of the correct behavioural response requires the suppression of a more prepotent or habitual response. Errors (failures to inhibit a reflexive prosaccade towards a sudden onset target) are significantly increased in patients with damage to the dorsolateral prefrontal cortex and patients with schizophrenia. Recent models of antisaccade performance suggest that errors are more likely to occur when the intention to initiate an antisaccade is insufficiently activated within working memory. Nicotine has been shown to enhance specific working memory processes in healthy adults. MATERIALS AND METHODS: We explored the effect of nicotine on antisaccade performance in a large sample (N = 44) of young adult smokers. Minimally abstinent participants attended two test sessions and were asked to smoke one of their own cigarettes between baseline and retest during one session only. RESULTS AND CONCLUSION: Nicotine reduced antisaccade errors and correct antisaccade latencies if delivered before optimum performance levels are achieved, suggesting that nicotine supports the activation of intentions in working memory during task performance. The implications of this research for current theoretical accounts of antisaccade performance, and for interpreting the increased rate of antisaccade errors found in some psychiatric patient groups are discussed

Marine epibiosis. II. Reduced fouling on Polysyncraton lacazei (Didemnidae, Tunicata) and proposal of an antifouling potential index

Polysyncraton lacazei is a colonial tunicate (family didemnidae) living in the NW-mediterranean rocky sublitoral. A thorough scanning of numerous colonies revealed that in spite of an apparently heavy local fouling pressure only one fouling species — a kamptozoan — is encountered with some regularity on Polysyncraton. We try to define the epibiotic situation of sessile marine organisms as composed of four epibiotic parameters: longevity or exposure time (A), epibiont load (E), colonizer pool (CP) and fouling-period (FP). Subsequently, these factors are combined to propose an “Antifouling Potential” index: AFP=(1−E/CP)×A/(FP+A). This index is intended to permit evaluating the relative antifouling defense potency to be expected in a given organism in a given epibiotic situation and to compare different cases of epibiosis and fouling

Nursing physical workload and mental workload in intensive care units: Are they related?

Aim In order to ensure patient safety and quality of care, it is important to consider factors which may impact on nursing workloads. This study aimed to investigate the simultaneous physical and mental workload and any relationships between these concepts on nurses working in intensive care units. Design A cross‐sectional design was undertaken. Method Participants were nurses (N = 105) recruited from six adult intensive care units which met the inclusion criteria. Nursing Activities Score (NAS) to measure physical workload and NASA Task Load Index (NASA‐TLX) to measure mental workload were used. Data were collected for each participating nurse in three shifts (morning, evening and night). Data were analysed using bivariate correlation and multivariable linear regression analysis. Results The mean (SD) of nurses' physical and mental workload was 72.84% (22.07%) and 70.21 (12.36), respectively. A significant relationship between physical and mental workload (p <.001) was identified

The meaning of actualization of self-care resources among a group of older home-dwelling people&#x2014;A hermeneutic study

Self-care is an activity of mature persons who have developed their abilities to take care of themselves. Individuals can choose to actualize their self-care abilities into self-care activities to maintain, restore, or improve health and well-being. It is of importance to understand the meaning of the actualization of self-care resources among older people. The aim of this study was to investigate the meaning of the actualization of self-care resources, i.e., actions taken to improve, maintain, or restore health and well-being, among a group of older home-dwelling individuals with a high sense of coherence. The design of this study was to reanalyse narratives revealing self-care activities from 11 (five females and six males) Norwegian older home-dwelling people (65 years or older) identified as having a high sense of coherence. In order to reveal the meaning and get an understanding of why these self-care resources were realized or actualized, a Gadamerian-based research method was chosen. The analysis revealed four themes that showed the meaning of actualization of self-care resources in the study group: &#x201C;Desire to carry on&#x201D;, &#x201C;Be of use to others&#x201D;, &#x201C;Self-realization&#x201D;, and &#x201C;Confidence to manage in the future&#x201D;. The findings showed what older people found meaningful to strive for, and this information can be used as a guide for health professionals when supporting older people in their self-care. Older people with self-care resources can also be an important resource for others in need of social contact and practical help. These resources have to be asked for in voluntary work among older people in need of help and, thereby, can be a valuable supplement to the community health care system