997 resultados para Galaxies: individual: M 51


Relevância:

20.00% 20.00%

Publicador:

Resumo:

Given that the ability to manage numbers is essential in a modern society, mathematics anxiety – which has been demonstrated to have unfortunate consequences in terms of mastery of math – has become a subject of increasing interest, and the need to accurately measure it has arisen. One of the widely employed scales to measure math anxiety is the Abbreviated Math Anxiety Scale (AMAS) (Hopko, Mahadevan, Bare & Hunt, 2003). The first aim of the present paper was to confirm the factor structure of the AMAS when administered to Italian high school and college students, and to test the invariance of the scale across educational levels. Additionally, we assessed the reliability and validity of the Italian version of the scale. Finally, we tested the invariance of the AMAS across genders. The overall findings provide evidence for the validity and reliability of the AMAS when administered to Italian students.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Studies of competition, predator–prey dynamics and food webs typically consider conspecifics as equal, however, individuals from the same population that are seemingly identical can show considerable variation with regards to a number of processes. Such phenomena may be demonstrated in terms of diet, and the quantities and types of resources that are consumed are commonly considered. The marine amphipod Echinogammarus marinus, a recently demonstrated predator on intertidal rocky shores, has been shown to consume a wide range of food types but it is unknown how this may vary between individuals. Here, we investigated the variation that occurs both among and within individuals of a population of E. marinus with respect to the mean numbers consumed of a common prey item, the isopod Jaera nordmanni. First, by comparing the length of starvation times, used as a proxy for hunger level, individuals maintained without food for up to 24 h consumed significantly less prey during feeding trials than those starved for 48 h and longer. The degree of inter-individual variation within each starvation period was also found to differ, with greater variation among individuals starved for shorter periods of time than those starved for longer time periods. Secondly, we tested whether individual amphipods tracked over time consumed consistently similar numbers of prey or whether they showed intra-individual variation, and if so, to what degree. We found that the numbers of prey consumed per individual could be predicted in the short-term between consecutive feeding trials, however over the long-term this relationship broke down. These results are discussed with respect to potential physiological and behavioural mechanisms, as well as the implications that such variation may have for stability of prey populations in the field.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

The association between aflatoxin intake from maize-based weaning food and aflatoxin albumin adducts (AF-alb) was investigated in 148 Tanzanian children aged between 12 and 22 months, at 2 visits 6 months apart. At the first visit (storage season) there was a significant correlation at the individual level between AF-alb (geometric mean 43.2 pg/mg albumin) and aflatoxin intake (geometric mean 81.7 ng/kg b.w./d) through maize-based weaning food (r = 0.51, p < 0.01). Overall, this correlation was r = 0.43 (p < 0.01). The AF-alb level in weaning-age children in Tanzania closely reflects aflatoxin intake from maize in weaning food. Exposure levels suggest children may be at risk from aflatoxin associated health effects.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Child protection social work is acknowledged as a very stressful occupation, with high turnover and poor retention of staff being a major concern. This paper highlights themes that emerged from findings of sixty-five articles that were included as part of a systematic literature review. The review focused on the evaluation of research findings, which considered individual and organisational factors associated with resilience or burnout in child protection social work staff. The results identified a range of individual and organisational themes for staff in child protection social work. Nine themes were identified in total. These are categorised under ‘Individual’ and ‘Organisational’ themes. Themes categorised as individual included personal history of maltreatment, training and preparation for child welfare, coping, secondary traumatic stress, compassion fatigue and compassion satisfaction. Those classified as organisational included workload, social support and supervision, organisational culture and climate, organisational and professional commitment, and job satisfaction or dissatisfaction. The range of factors is discussed with recommendations and areas for future research are highlighted.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

The expanding remnant from SN 1987A is an excellent laboratory for investigating the physics of supernovae explosions. There is still a large number of outstanding questions, such as the reason for the asymmetric radio morphology, the structure of the pre-supernova environment, and the efficiency of particle acceleration at the supernova shock. We explore these questions using three-dimensional simulations of the expanding remnant between days 820 and 10,000 after the supernova. We combine a hydrodynamical simulation with semi-analytic treatments of diffusive shock acceleration and magnetic field amplification to derive radio emission as part of an inverse problem. Simulations show that an asymmetric explosion, combined with magnetic field amplification at the expanding shock, is able to replicate the persistent one-sided radio morphology of the remnant. We use an asymmetric Truelove &amp; McKee progenitor with an envelope mass of 10 M-circle dot and an energy of 1.5 x 10(44) J. A termination shock in the progenitor's stellar wind at a distance of 0 ''.43-0 ''.51 provides a good fit to the turn on of radio emission around day 1200. For the H II region, a minimum distance of 0 ''.63 +/- 0 ''.01 and maximum particle number density of (7.11 +/- 1.78) x 10(7) m(-3) produces a good fit to the evolving average radius and velocity of the expanding shocks from day 2000 to day 7000 after explosion. The model predicts a noticeable reduction, and possibly a temporary reversal, in the asymmetric radio morphology of the remnant after day 7000, when the forward shock left the eastern lobe of the equatorial ring.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Research on admissions to care homes for older people has paid more attention to individual and social characteristics than to geographical factors. This paper considers rural-urban differences in household composition and admission rates. Cohort: 51,619 people aged 65 years or older at the time of the 2001 Census and not living in a care home, drawn from a data linkage study based on c.28% of the Northern Ireland population.Living alone was less common in rural areas; 25% of older people in rural areas lived with children compared to 18% in urban areas. Care home admission was more common in urban (4.7%) and intermediate (4.3%) areas than in rural areas (3.2%). Even after adjusting for age, sex, health and living arrangements, the rate of care home admission in rural areas was still only 75% of that in urban areas.People in rural areas experience better family support by living as part of two or three generation households. Even after accounting for this difference, older rural dwellers are less likely to enter care homes; suggesting that neighbours and relatives in rural areas provide more informal care; or that there may be differential deployment of formal home care services.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Burkholderia cepacia complex organisms are important transmissible pathogens found in cystic fibrosis (CF) patients. In recent years, the rates of cross-infection of epidemic strains have declined due to effective infection control efforts. However, cases of sporadic B. cepacia complex infection continue to occur in some centers. The acquisition pathways and clinical outcomes of sporadic B. cepacia complex infection are unclear. We sought to determine the patient clinical characteristics, outcomes, incidence, and genotypic relatedness for all cases of B. cepacia complex infection at two CF centers. We also sought to study the external conditions that influence the acquisition of infection. From 2001 to 2011, 67 individual organisms were cultured from the respiratory samples of 64 patients. Sixty-five percent of the patients were adults, in whom chronic infections were more common (68%) (P = 0.006). The incidence of B. cepacia complex infection increased by a mean of 12% (95% confidence interval [CI], 3 to 23%) per year. The rates of transplantation and death were similar in the incident cases who developed chronic infection compared to those in patients with chronic Pseudomonas aeruginosa infection. Multilocus sequence typing revealed 50 individual strains from 65 isolates. Overall, 85% of the patients were infected with unique strains, suggesting sporadic acquisition of infection. The yearly incidence of nonepidemic B. cepacia complex infection was positively correlated with the amount of rainfall in the two sites examined: subtropical Brisbane (r = 0.65, P = 0.031) and tropical Townsville (r = 0.82, P = 0.002). This study demonstrates that despite strict cohort segregation, new cases of unrelated B. cepacia complex infection continue to occur. These data also support an environmental origin of infection and suggest that climate conditions may be associated with the acquisition of B. cepacia complex infections.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

The conventional wisdom in the transitional justice literature is that there is no one-size-fits-all approach. This article suggests that this may also be true within a given state. The current paper reports on quantitative and qualitative data from 184 participants in a survey conducted in the Caribbean coast of Colombia. Results suggest widespread support for transitional justice mechanisms – such as perpetrator accountability, public acknowledgement and structural change – but dissatisfaction with national-level initiatives, specifically the 2005 Justice and Peace Law. Yet, despite a distrust of the national government and protracted conflict, individuals report social trust, community cohesion and reliance on local government institutions. These attitudes and behaviours suggest that decentralised transitional justice mechanisms may be more effective in meeting victims' needs. Moreover, analyses indicate that individual preferences are influenced by community factors, such as the presence of demobilised paramilitaries, which can be addressed through more localised approaches to promote peacebuilding. The paper concludes with best practices derived from the findings.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

We present new Herschel photometric and spectroscopic observations of Supernova 1987A, carried out in 2012. Our dedicated photometric measurements provide new 70 mu m data and improved imaging quality at 100 and 160 mu m compared to previous observations in 2010. Our Herschel spectra show only weak CO line emission, and provide an upper limit for the 63 mu m [O-I] line flux, eliminating the possibility that line contaminations distort the previously estimated dustmass. The far-infrared spectral energy distribution (SED) is well fitted by thermal emission from cold dust. The newly measured 70 mu m flux constrains the dust temperature, limiting it to nearly a single temperature. The far-infrared emission can be fitted by 0.5 +/- 0.1M(circle dot) of amorphous carbon, about a factor of two larger than the current nucleosynthetic mass prediction for carbon. The observation of SiO molecules at early and late phases suggests that silicates may also have formed and we could fit the SED with a combination of 0.3M(circle dot) of amorphous carbon and 0.5M(circle dot) of silicates, totalling 0.8M(circle dot) of dust. Our analysis thus supports the presence of a large dust reservoir in the ejecta of SN 1987A. The inferred dust mass suggests that supernovae can be an important source of dust in the interstellar medium, from local to high-redshift galaxies.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Experimental results on relativistic surface HHG at a repetition rate of 10 Hz are presented. Average powers in the 10?W range are generated in the spectral range of 51 to 26 nm (24-48 eV). The surface harmonic radiation is produced by focusing the second-harmonic of a high-power laser onto a rotating glass surface to moderately relativistic intensities of 3×10 19Wcm ?2. The harmonic emission exhibits a divergence of 26 mrad. Together with absolute photon numbers recorded by a calibrated spectrometer, this allows for the determination of the extreme ultraviolet (XUV) yield. The pulse energies of individual harmonics are reaching up to the μJ level, equivalent to an efficiency of 10 ?5. The capability of producing stable and intense high-harmonic radiation from relativistic surface plasmas may facilitate experiments on nonlinear ionization or the seeding of free-electron lasers. © IOP Publishing Ltd and Deutsche Physikalische Gesellschaft.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Background: Adherence to treatment is low in bronchiectasis and is associated with poorer health outcomes. Factors affecting adherence decisions have not been explored in patients with bronchiectasis. 

Objective: We aimed to explore patients' perspectives on adherence, factors affecting adherence decision making and to develop a conceptual model explaining this decision-making process in adults with bronchiectasis. 

Methods: Adults with bronchiectasis participated in one-to-one semi-structured interviews. Interviews were audio-recorded, transcribed verbatim and analysed independently by two researchers using thematic analysis. Data from core themes were extracted, categorized into factors affecting adherence decision making and used to develop the conceptual model. 

Results: Participants' beliefs about treatment, the practical aspects of managing treatment, their trust in health-care professionals and acceptance of disease and treatment were important aspects of treatment adherence. The conceptual model demonstrated that adherence decisions were influenced by participants' individual balance of barriers and motivating factors (treatment-related, disease-related, health-care-related, personal and social factors). 

Conclusion: Adherence decision-making in bronchiectasis is complex, but there is the potential to enhance adherence by understanding patients' specific barriers and motivators to adherence and using this to tailor adherence strategies to individual patients and treatments. © 2014 John Wiley &amp; Sons Ltd.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Despite plant secondary metabolites being major determinants of species interactions and ecosystem processes, their role in the maintenance of biodiversity has received little attention. In order to investigate the relationship between chemical and biological diversity in a natural ecosystem, we considered the impact of chemical diversity in individual Scots pine trees (Pinus sylvestris) on species richness of associated ground vegetation. Scots pine trees show substantial genetically determined constitutive variation between individuals in concentrations of a group of secondary metabolites, the monoterpenes. When the monoterpenes of particular trees were assessed individually, there was no relationship with species richness of associated ground flora. However, the chemical diversity of monoterpenes of individual trees was significantly positively associated with the species richness of the ground vegetation beneath each tree, mainly the result of an effect among the non-woody vascular plants. This correlation suggests that the chemical diversity of the ecosystem dominant species has an important role in shaping the biodiversity of the associated plant community. The extent and significance of this effect, and its underlying processes require further investigation.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Biofilms are communities of microbial cells that underpin diverse processes including sewage bioremediation, plant growth promotion, chronic infections and industrial biofouling. The cells resident in the biofilm are encased within a self-produced exopolymeric matrix that commonly comprises lipids, proteins that frequently exhibit amyloid-like properties, eDNA and exopolysaccharides. This matrix fulfils a variety of functions for the community, from providing structural rigidity and protection from the external environment to controlling gene regulation and nutrient adsorption. Critical to the development of novel strategies to control biofilm infections, or the capability to capitalize on the power of biofilm formation for industrial and biotechnological uses, is an in-depth knowledge of the biofilm matrix. This is with respect to the structure of the individual components, the nature of the interactions between the molecules and the three-dimensional spatial organization. We highlight recent advances in the understanding of the structural and functional role that carbohydrates and proteins play within the biofilm matrix to provide three-dimensional architectural integrity and functionality to the biofilm community. We highlight, where relevant, experimental techniques that are allowing the boundaries of our understanding of the biofilm matrix to be extended using Escherichia coli, Staphylococcus aureus, Vibrio cholerae, and Bacillus subtilis as exemplars.