589 research outputs found

    First record of the sea anemone Metridium senile from South Africa

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    A sea anemone new to the South African fauna is reported from Table Bay Harbour and is identified as Metridium senile. The population was probably introduced from Europe and although well established, appears to be restricted to the harbour area

    Assessment of induced rat mammary tumour response to chemotherapy using the apparent diffusion coefficient of tissue water as determined by diffusion-weighted 1H-NMR spectroscopy in vivo.

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    Chemosensitivity of N-methyl-N-nitrosourea-induced rat mammary tumours treated with 5-fluorouracil at a dose of 100 mg kg(-1) i.p. was assessed by using diffusion-weighted 1H-MRS to measure the average diffusion coefficient (ADC) of water in the tumour tissue. ADC measurements prior to any therapy correlated positively with necrotic fraction. Tumours with low initial ADC (< 0.95 x 10(9) m2 s(-1)) showed an increase in ADC 7 days after treatment, whereas tumours with a high initial ADC (> 1.2 x 10(9) m2 s(-1)) showed a decrease. All tumours decreased significantly in volume (P < 0.05) 2, 5 and 7 days after treatment. At day 7 post-treatment, tumours with a high pre-treatment ADC started to regrow. The initial ADC value, as well as changes after treatment predict tumour chemosensitivity, which could be clinically relevant

    Treating reading difficulties with colour [Editorial]

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    yesAround 3-6% of children in the United Kingdom have substantial difficulties learning to read, a condition often referred to as dyslexia. They are at high risk of educational underachievement. In a 1996 editorial in The BMJ, Margaret Snowling argued that dyslexia is a verbal (not a visual) disorder.1 An accumulation of evidence supports this position and shows that reading difficulties are best dealt with by interventions that target underlying weaknesses in phonological language skills and letter knowledge.2 The 2009 Rose report, which provides guidance for professionals in schools on identifying and teaching young people with dyslexia and reading difficulties, stresses the importance of early, phonological interventions.3 Despite this evidence, dyslexia is often associated with subjective experiences of visual distortions that lead to discomfort during reading (sometimes termed visual stress). It has been argued that these symptoms can be alleviated by using coloured overlays and lenses.4 Symptoms of visual stress are not unique to dyslexia, and proponents do not claim that the use of colour directly addresses the underlying cause of the reading difficulty. However, they argue that the reduction in visual distortion brought about by a change in colour can improve reading accuracy and fluency.

    Treating reading difficulties with colour: Authors’ reply to Evans and Allen

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    yesWe thank Professors Evans and Allen for their interest in our article.1 2 The charity websites we reviewed refer to colour as though it offers a scientific, evidence based treatment; none referred to feedback from the membership. For example, one charity website makes the claim that “Research in the UK and in Australia shows that people who need coloured filters, who are said to have visual stress, need to have exactly the right colour.” This is incorrect. The research overwhelmingly shows little advantage, or at best conflicting results.3 4

    Evaluation of a commercially available pedometer used to promote physical activity as part of a national programme

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    Objective: To assess the accuracy of a pedometer (manufactured by Silva) currently being used as part of a national programme to promote physical activity in the UK. Methods: Laboratory study: 68 participants (age 19.2±2.7 years, BMI 22.5±3.3 kg/m2) wore 2 Silva pedometers (over the right and left hips) whilst walking on a motorised treadmill at 2, 2.5, 3, 3.5 and 4mph. Pedometer step counts were compared with actual steps counted. Free-living study: 134 participants (age 36.4±18.1 years, BMI 26.3±5.1 kg/m2) wore one Silva pedometer, one New-Lifestyles NL-1000 pedometer and an ActiGraph GT1M accelerometer (the criterion) during waking hours for one day. Step counts registered by the Silva and NL- 1000 pedometers were compared to ActiGraph step counts. Percent error of the pedometers were compared across normal-weight (n=58), overweight (n=45) and obese (n=31) participants. Results: Laboratory study: Across the speeds tested percent error in steps ranged from 6.7 (4mph) – 46.9% (2mph). Free-living study: Overall percent errors of the Silva and NL-1000 pedometers relative to the criterion were 36.3% and 9% respectively. Significant differences in percent error of the Silva pedometer were observed across BMI groups (normal-weight 21%, overweight 40.2%, obese 59.2%, P<0.001). Conclusion: The findings suggest the Silva pedometer is unacceptably inaccurate for activity promotion purposes particularly in overweight and obese adults. Pedometers are an excellent tool for activity promotion however the use of inexpensive, untested pedometers is not recommended as they will lead to user frustration, low intervention compliance, and adverse reaction to the instrument, potentially impacting future public health campaigns

    Many worlds in one

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    A generic prediction of inflation is that the thermalized region we inhabit is spatially infinite. Thus, it contains an infinite number of regions of the same size as our observable universe, which we shall denote as \O-regions. We argue that the number of possible histories which may take place inside of an \O-region, from the time of recombination up to the present time, is finite. Hence, there are an infinite number of \O-regions with identical histories up to the present, but which need not be identical in the future. Moreover, all histories which are not forbidden by conservation laws will occur in a finite fraction of all \O-regions. The ensemble of \O-regions is reminiscent of the ensemble of universes in the many-world picture of quantum mechanics. An important difference, however, is that other \O-regions are unquestionably real.Comment: 9 pages, 2 figures, comments and references adde

    Prediction of near field overpressure from quarry blasting

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    This paper investigates the propagation of airblast or pressure waves in air produced by bench blasting (i.e. detonation of the explosive in a row of blastholes, breaking the burden of rock towards the free vertical face of the block). Peak overpressure is calculated as a function of blasting parameters (explosive mass per delay and velocity at which the detonation sequence proceeds along the bench) and the polar coordinates of the position of interest (distance to the source and azimuth with respect to the free face). The model has been fitted to empirical data using linear least squares. The data set is composed of 122 airblast records monitored at distances less than 400 m in 41 production blasts carried out in two quarries. The model is statistically significant and has a determination coefficient of 0.87. The formula is validated from 12 airblast measurements gathered in five additional blasts

    Type IIB Colliding Plane Waves

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    Four-dimensional colliding plane wave (CPW) solutions have played an important role in understanding the classical non-linearities of Einstein's equations. In this note, we investigate CPW solutions in 2n+22n+2--dimensional Einstein gravity with a n+1n+1-form flux. By using an isomorphism with the four-dimensional problem, we construct exact solutions analogous to the Szekeres vacuum solution in four dimensions. The higher-dimensional versions of the Khan-Penrose and Bell-Szekeres CPW solutions are studied perturbatively in the vicinity of the light-cone. We find that under small perturbations, a curvature singularity is generically produced, leading to both space-like and time-like singularities. For n=4n=4, our results pertain to the collision of two ten-dimensional type IIB Blau - Figueroa o'Farrill - Hull - Papadopoulos plane waves.Comment: 20+10 pages, 2 figures, uses JHEP3.cls; v2: refs [3,10,22] corrected, remark added below (3.9) on inexistence of conformally flat CPW in our ansatz, final version to appear in JHE

    Use of traditional and complementary medicine as self-care strategies in community health centers

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    In China, Community Health Centers (CHCs) are major providers of primary care services, but their potential in empowering patients’ self-management capacity has not been assessed. This study aims to describe self-care practice patterns amongst CHC attendees in urban China. In this cross-sectional quantitative study, 3360 CHC patients from 6 cities within the Pearl Delta Region were sampled using multistage cluster sampling. Thirty-seven per cent had used with over-the-counter Chinese herbal medicines (OTC CHMs) in the past year and majority of respondents found OTC CHMs effective. OTC CHMs were more popular amongst those who needed to pay out of pocket for CHC services. Less than 10% used vitamins and minerals, and those with a lower socioeconomic background have a higher propensity to consume. Although doubts on their usefulness are expressed, their use by the vulnerable population may reflect barriers to access to conventional health care, cultural affinity, or a defense against negative consequences of illnesses. About 25% performed physical exercise, but the prevalence is lower amongst women and older people. Taiji seems to be an alternative for these populations with promising effectiveness, but overall only 6% of CHC attendees participated. These results suggest that CHCs should start initiatives in fostering appropriate use of OTC CHM, vitamins, and minerals. Engaging community pharmacists in guiding safe and effective use of OTC CHM amongst the uninsured is essential given their low accessibility to CHC services. Prescription of Taiji instead of physical exercises to women and older people could be more culturally appropriate, and the possibility of including this as part of the CHC services worth further exploration

    Single stranded fully Modified-Phosphorothioate oligonucleotides can induce structured nuclear inclusions, alter nuclear protein localization and disturb the transcriptome In Vitro

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    Oligonucleotides and nucleic acid analogues that alter gene expression are now showing therapeutic promise in human disease. Whilst the modification of synthetic nucleic acids to protect against nuclease degradation and to influence drug function is common practice, such modifications may also confer unexpected physicochemical and biological properties. Gapmer mixed-modified and DNA oligonucleotides on a phosphorothioate backbone can bind non-specifically to intracellular proteins to form a variety of toxic inclusions, driven by the phosphorothioate linkages, but also influenced by the oligonucleotide sequence. Recently, the non-antisense or other off-target effects of 2′ O- fully modified phosphorothioate linkage oligonucleotides are becoming better understood. Here, we report chemistry-specific effects of oligonucleotides composed of modified or unmodified bases, with phosphorothioate linkages, on subnuclear organelles and show altered distribution of nuclear proteins, the appearance of highly stable and strikingly structured nuclear inclusions, and disturbed RNA processing in primary human fibroblasts and other cultured cells. Phosphodiester, phosphorodiamidate morpholino oligomers, and annealed complimentary phosphorothioate oligomer duplexes elicited no such consequences. Disruption of subnuclear structures and proteins elicit severe phenotypic disturbances, revealed by transcriptomic analysis of transfected fibroblasts exhibiting such disruption. Our data add to the growing body of evidence of off-target effects of some phosphorothioate nucleic acid drugs in primary cells and suggest alternative approaches to mitigate these effects
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