1,603 research outputs found
Biphasic behaviour in malignant invasion
Invasion is an important facet of malignant growth that enables tumour cells to colonise adjacent regions of normal tissue. Factors known to influence such invasion include the rate at which the tumour cells produce tissue-degrading molecules, or proteases, and the composition of the surrounding tissue matrix. A common feature of experimental studies is the biphasic dependence of the speed at which the tumour cells invade on properties such as protease production rates and the density of the normal tissue. For example, tumour cells may invade dense tissues at the same speed as they invade less dense tissue, with maximal invasion seen for intermediate tissue densities. In this paper, a theoretical model of malignant invasion is developed. The model consists of two coupled partial differential equations describing the behaviour of the tumour cells and the surrounding normal tissue. Numerical methods show that the model exhibits steady travelling wave solutions that are stable and may be smooth or discontinuous. Attention focuses on the more biologically relevant, discontinuous solutions which are characterised by a jump in the tumour cell concentration. The model also reproduces the biphasic dependence of the tumour cell invasion speed on the density of the surrounding normal tissue. We explain how this arises by seeking constant-form travelling wave solutions and applying non-standard phase plane methods to the resulting system of ordinary differential equations. In the phase plane, the system possesses a singular curve. Discontinuous solutions may be constructed by connecting trajectories that pass through particular points on the singular curve and recross it via a shock. For certain parameter values, there are two points at which trajectories may cross the singular curve and, as a result, two distinct discontinuous solutions may arise
Local Climatological Data : Urbana, 1889-1970
Urbana has a temperate continental climate with characteristics reflecting its geographical position in Illinois. Urbana's climate is representative of the conditions found in East Central Illinois, which is primarily an area of climatic transition between the northern and southern sectors of the state.published or submitted for publicationis peer reviewedOpenOpe
Noise Impacts from Professional Dog Grooming Forced-Air Dryers
This study was designed to measure the sound output of four commonly used brands of forced-air dryers used by dog groomers in the United States. Many dog groomers have questions about the effect of this exposure on their hearing, as well as on the hearing of the dogs that are being groomed. Readings taken from each dryer at 1 meter (the likely distance of the dryer from the groomer and the dog) showed average levels ranging from 105.5 to 108.3 dB SPL or 94.8 to 108.0 dBA. Using the 90 dBA criterion required by the US Occupational Safety and Health Administration, dog groomers/bathers are at risk if exposure to the lowest intensity dryer (94.8 dBA) exceeds 4 hours per day. If the more stringent 85 dBA criterion and 3 dB tradeoff is applied, less than one hour of exposure is permissible in an 8 hour day. Cautions are recommended for any persons exposed to noise from forced-air dryers
Management of a girl with delayed puberty and elevated gonadotropins
A girl presenting with delayed puberty and elevated gonadotropins may have a range of conditions such as Turner Syndrome (TS), Primary Ovarian Insufficiency (POI) and 46,XY DSD. An organized and measured approach to investigation can help reach a timely diagnosis. Management of young people often requires specialist multidisciplinary input to address the endocrine and non-endocrine features of these complex conditions, as well as the psychological challenges posed by their diagnosis. Next generation sequencing within the research setting has revealed several genetic causes of POI and 46,XY DSD which may further facilitate an individualized approach to care of these young people in the future. Pubertal induction is required in many and the timing of this may need to be balanced with other issues specific to the condition (e.g., allowing time for information-sharing in 46,XY DSD, optimizing growth in TS). Shared decision-making and sign-posting to relevant support groups from the outset can help empower young people and their families to manage these conditions. We describe three clinical vignettes of girls presenting with delayed puberty and hypergonadotropic amenorrhea and discuss their clinical management in the context of current literature and guidelines
The influence of beta-1,3-1,6-glucans on rabies vaccination titers in cats
beta-glucans have been shown to stimulate the immune system in several animal species. The aim of this study was to evaluate the immune stimulation capacity of a fully formulated diet with beta-1,3-1,6-glucans in cats, by assessing the rabies antibody titer after vaccination. Thirty-five healthy cats were recruited. The cats were placed into two groups and fed a standard diet in accordance with body weight. One group had the beta-glucans incorporated into the diet; the other group served as the control group. After two weeks of dietary adjustment; the rabies vaccine (Imrab(R)3 TF; Merial) was administered on days 0 and 21. Blood samples were taken on days 0, 21, and 42. Titers were determined with the rapid fluorescent foci inhibition test (RFFIT). Titers at days 21 and 42 were compared between the two groups in a linear mixed effects model. This study showed that the animals receiving the non-supplemented feed had higher post-vaccination rabies antibody titers. This indicates that, in contrast to other animal species, the beta-glucan supplemented diet did not have the expected positive effect on the rabies antibody titers in cats
Conceptualizing gratitude and appreciation as a unitary personality trait
Gratitude and appreciation are currently measured using three self-report instruments, the GQ6 (1 scale), the Appreciation Scale (8 scales), and the GRAT (3 scales). Two studies were conducted to test how these three instruments are interrelated, whether they exist under the same higher order factor or factors, and whether gratitude and appreciation is a single or multi-factorial construct. In Study 1 (N = 206) all 12 scales were subjected to an exploratory factor analysis. Both parallel analysis and the minimum average partial method indicated a clear one-factor solution. In Study 2 (N = 389) multigroup confirmatory factor analysis supported the one-factor structure, demonstrated the invariance of this structure across gender, and ruled out the confounding effect of socially desirable responding. We conclude gratitude and appreciation are a single-factor personality trait. We suggest integration of gratitude and appreciation literatures and provide a clearer conceptualization of gratitude
Children’s rights to education:Where is the weight for children’s views?
This paper analyses the views and preferences of children and young people who experience barriers when attempting to engage with schools and schooling. It specifically considers processes of formal and informal exclusion and the manner in which ‘stigmatised’ children are treated within a system that’s attendance to children’s rights is, at best, sketchy and at worst - downright discriminatory. The paper poses a number of critical questions concerning the extent to which the views of children are given due weight in decision-making processes in schools, whether the background a child comes from affects the way school staff listen to them and whether school rules act as a barrier or enabler for children’s rights. In turn, these questions are related to what educational processes might look like that place due weight on the views of children, what cultures create barriers to listening in practice, and what we can learn from children’s overall experiences. The paper presents findings from a participatory empirical peer research project (funded by a Carnegie Research Incentive Grant and the University of Edinburgh Challenge Investment Fund) conducted with and by young people in schools in Scotland and the north of England. This paper is innovative as it is the product of collaborative working between academics at the University of Edinburgh, staff at Investing in Children and the young researchers who co-authored this article for publication
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