1,316 research outputs found

    Physical parameters of a relativistic jet at very high redshift: the case of the blazar J1430+4204

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    Context. The high-redshift (z = 4.72) blazar J1430+4204 produced a major radio outburst in 2005. Such outbursts are usually associated with the emergence of a new component in the inner radio jet. Aims. We searched for possible changes in the radio structure on milli-arcsecond angular scales, to determine physical parameters that characterise the relativistic jet ejected from the centre of this source. Methods. We analysed 15-GHz radio interferometric images obtained with the Very Long Baseline Array (VLBA) before and after the peak of the outburst. Results. We did not identify any significant new jet component over a period of 569 days. We estimated the Doppler factor, the Lorentz factor, and the apparent transverse speed of a putative jet component using three different methods. The likely small jet angle to the line of sight and our values of the apparent transverse speed are consistent with not detecting a new jet feature.Comment: (6 pages, 4 figures) accepted for publication in Astronomy and Astrophysic

    Types and correlates of school non-attendance in students with autism spectrum disorders

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    School non-attendance in autism spectrum disorders (ASD) has received very little attention to date. The study aimed to provide a comprehensive description of school non-attendance in students with ASD. Through an online survey, parents of 486 children (mean age 11 years) reported on school attendance over one month, and reasons for instances of non-attendance. On average, students missed five days of school of a possible 23 days. Persistent non-attendance (absent on 10%+ of available sessions) occurred among 43% of students. School non-attendance was associated with child older age, not living in a two-parent household, parental unemployment and, especially, attending a mainstream school. School refusal accounted for 43% of non-attendance. School exclusion and school withdrawal each accounted for 9% of absences. Truancy was almost non-existent. Non-problematic absenteeism (mostly related to medical appointments and illness) accounted for 32% of absences. Non-problematic absenteeism was more likely among those with intellectual disability, school refusal was more likely among older students, and school exclusion was more likely among students from single-parent, unemployed, and well educated households. Findings suggest school non-attendance in ASD is a significant issue, and that it is important to capture detail about attendance patterns and reasons for school non-attendance

    Who cooks from scratch and how do they prepare food

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    Purpose – There is increasing interest in the domestic preparation of food and with the postulated health benefits of “cooking from scratch”. The purpose of this paper is to examine the demographic and food preparation associations of this term in order to examine its operational value. Design/methodology/approach – A national online survey was conducted during 2012 in Australia among 1,023 domestic food providers, half of whom were men. Questions were asked about cooking from scratch, demographic characteristics, food preparation practices and interest in learning about cooking. Findings – Three quarters of the sample reported they often or always “cooked from scratch” (CFS). More women than men always CFS; fewer 18-29 year olds did so often or always but more of the over 50s always did so; fewer single people CFS than cohabiting people. No statistically significant ethnic, educational background or household income differences were found. High levels of cooking from scratch were associated with interest in learning more about cooking, greater use of most cooking techniques (except microwaves), meat and legume preparation techniques, and the use of broader ranges of herbs, spice, liquids/ sauces, other ingredients and cooking utensils. Research limitations/implications – In future work a numerical description of the frequency of cooking from scratch should be considered along with a wider range of response options. The data were derived from an online panel from which men were oversampled. Caution is required in comparisons between men and women respondents. The cross-sectional nature of the sample prevents any causal attributions from being drawn from the observed relationships. Further replication of the findings, especially the lack of association with educational background should be conducted. Originality/value – This is the first study to examine the associations of demographic characteristics and cooking practices with cooking from scratch. The findings suggest that cooking from scratch is common among Australian family food providers and signifies interest in learning about cooking and involvement in a wide range of cooking techniques

    Factors influencing fruit and vegetable intake among urban Fijians: A qualitative study.

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    Low fruit and vegetable intake is an important risk factor for micronutrient deficiencies and non-communicable diseases, but many people worldwide, including most Fijians, eat less than the World Health Organization recommended amount. The present qualitative study explores factors that influence fruit and vegetable intake among 57 urban Fijians (50 women, 7 men) of indigenous Fijian (iTaukei) and South Asian (Indian) descent. Eight focus group discussions were held in and around Suva, Fiji's capital and largest urban area, which explored motivation for eating fruit and vegetables, understandings of links to health and disease, availability and sources, determinants of product choice, and preferred ways of preparing and eating fruit and vegetables. Data were analysed using thematic content analysis. Regardless of ethnicity, participants indicated that they enjoyed and valued eating fruit and vegetables, were aware of the health benefits, and had confidence in their cooking skills. In both cultures, fruit and vegetables were essential components of traditional diets. However, increasing preferences for processed and imported foods, and inconsistent availability and affordability of high-quality, low-priced, fresh produce, were identified as important barriers. The findings indicate that efforts to improve fruit and vegetable intake in urban Fijians should target the stability of the domestic fruit and vegetable supply and access

    Chemical ecology of antibiotic production by actinomycetes

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    Actinomycetes are a diverse family of filamentous bacteria that produce a plethora of natural products relevant for agriculture, biotechnology and medicine, including the majority of the antibiotics we use in the clinic. Rather than as free-living bacteria, many actinomycetes have evolved to live in symbiosis with among others plants, fungi, insects and sponges. As a common theme, these organisms profit from the natural products and enzymes produced by the actinomycetes, for example, for protection against pathogenic microbes, for growth promotion or for the degradation of complex natural polymers such as lignocellulose. At the same time, the actinomycetes benefit from the resources of the hosts they interact with. Evidence is accumulating that these interactions control the expression of biosynthetic gene clusters and have played a major role in the evolution of the high chemical diversity of actinomycete-produced secondary metabolites. Many of the biosynthetic gene clusters for antibiotics are poorly expressed under laboratory conditions, but they are likely expressed in response to host-specific demands. Here, we review the environmental triggers and cues that control natural product formation by actinomycetes and provide pointers as to how these insights may be harnessed for drug discovery
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