861 research outputs found
Models of OH Maser Variations in U Her
Arecibo spectra of the mainline OH maser emission from U Her over more than a
decade show variations of the OH emission over these time scales. These
observations are combined with high spatial resolution VLBA maps to investigate
the causes of the variations in the velocities of the maser components. Global
properties of the dust shell, such as accelerations, variations in the pump and
shell-wide magnetic field changes are examined as possibilities, and
eliminated. A possible solution to the problem involving plasma turbulence and
the local magnetic field is introduced, and the relevant time scales of the
turbulence are calculated. The turbulent velocity field yields time scales of
the turbulence are calculated. The turbulent velocity field yields time scales
that are too long (of order centuries), while the turbulent magnetic field
produces variations on appropriate time scales of a few years. A line-of-sight
model of the turbulence is developed and investigated. The complete exploration
of this solution requires extensive theoretical and observational work.
Possible avenues of investigation of the plasma turbulence model are presented.Comment: 23 pages, 17 figures, ApJ: accepted Sept, 199
Effects of neonicotinoid exposure on molecular and physiological indicators of honey bee immunocompetence
This is the author accepted manuscript. The final version is available from Springer Verlag via the DOI in this recordBee declines have been associated with various stressors including pesticides and pathogens. We separately exposed immune-challenged adult worker honey bees (Apis mellifera L.) to two neonicotinoid pesticides, thiamethoxam (10Â ppb) and imidacloprid (102Â ppb), by dietary delivery. We found that whereas neonicotinoid exposure weakly affected transcriptional responses of antimicrobial genes, it did not detectably affect the physiological antimicrobial response as measured by a lytic clearance assay of haemolymph. Our findings add to the evidence that transcriptional responses in immune-related genes are not yet reliable indicators of pesticide impacts on bee health, which suggests caution in their future use as biomarkers in pesticide risk assessment.E.J.C was funded by a joint University of Exeter-Fera studentship
Quantifying performance of ultrasonic immersion inspection using phased arrays for curvilinear disc forgings
Use of full-matrix capture (FMC), combined with the total focusing method (TFM), has been shown to provide improvements to flaw sensitivity within components of irregular geometry. Ultrasonic immersion inspection of aerospace discs requires strict specifications to ensure full coverage – one of which is that all surfaces should be machined flat. The ability to detect defects through curved surfaces, with an equivalent sensitivity to that obtained through flat surfaces could bring many advantages. In this work, the relationship between surface curvature and sensitivity to standard defects was quantified for various front wall radii. Phased array FMC immersion inspection of curved components was simulated using finite element modelling, then visualized using surface-compensated focusing techniques. This includes the use of BRAIN software developed at the University of Bristol for production of TFM images. Modelling results were compared to experimental data from a series of test blocks with a range of curvatures, containing standard defects. The sensitivity to defects is evaluated by comparing the performance to conventional methods. Results are used to highlight the benefits and limitations of these methods relating to the application area of aerospace engine disc forgings
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Complexity of women's modern-day challenges in construction
Purpose: Although the UK construction sector has enjoyed a significant rise in the number of women, there is undoubtedly more room for improvement. Numerous schemes have been initiated by government and other professional bodies to encourage more women to join the industry. This paper sheds light on the organizational complexities of problems faced by women working in professional roles in construction. It thus initiates a dialogue on the lack of workplace flexibility and discriminatory practices that prevent many more women from joining.
Design/methodology/approach: An interpretivist philosophy is adopted. The research critically explores the views of women working professional roles in six large construction firms in the UK.
Findings: It was widely acknowledged that the industry had improved significantly, however there are still concerns yet to be addressed. It was identified that many women struggle to re-enter the industry after embarking on maternity leave. Furthermore, it is believed that some workplace progressions were only due to senior managers’ attempt to demonstrate a level of inclusivity rather than due to merit.
Research limitations/implications: Sample size and narrow focus on large construction firms.
Practical implications: Through academic and industry dissemination, the findings from this research encourage both men and women working in the construction industry to adopt inclusive practices that will help widen the pool of knowledge and expertise.
Social implications: This paper sheds light on a problem that has prevented women from joining the industry many years.
Originality/value: This presents an in-depth critical perspective of challenges faced by women construction professionals
Legal determinants of external finance revisited : the inverse relationship between investor protection and societal well-being
This paper investigates relationships between corporate governance traditions and quality of life as measured by a number of widely reported indicators. It provides an empirical analysis of indicators of societal health in developed economies using a classification based on legal traditions. Arguably the most widely cited work in the corporate governance literature has been the collection of papers by La Porta et al. which has shown, inter alia, statistically significant relationships between legal traditions and various proxies for investor protection. We show statistically significant relationships between legal traditions and various proxies for societal health. Our comparative evidence suggests that the interests of investors may not be congruent with the interests of wider society, and that the criteria for judging the effectiveness of approaches to corporate governance should not be restricted to financial metrics
The psychometric properties of the grazing questionnaire in an obesity sample with and without binge eating disorder
Background: Despite being the first validated measure of grazing, the Grazing Questionnaire (GQ) has not been investigated among individuals with obesity. Therefore, the current study aimed to examine the psychometric properties of the GQ in an obesity sample. Methods: Participants (N=259) were recruited from community and clinical settings in Australia. The sample comprised adults with normal weight (n=77) and obesity (n=182). A portion of individuals with obesity (n=102) had binge eating disorder (BED). Data from the obesity group was examined to establish the factor structure, validity, and reliability of the GQ. A one-way ANOVA with planned contrasts was conducted to compare scores on the GQ across groups. Results: Confirmatory factor analysis revealed that the 2-factor model of the GQ was the best model ft for individuals with obesity. The GQ demonstrated high internal consistency, test–retest reliability over 3 months, and convergent and divergent validity. As hypothesised, the obesity group had significantly higher scores on the GQ than the normal weight group, while the obesity with BED group had significantly higher scores than the obesity without BED group. Conclusion: This was the first study to investigate the psychometric properties of the GQ in an obesity sample. Overall, findings indicated that the GQ is a psychometrically sound measure of grazing among individuals with obesity. These findings provide further support for two distinct subtypes of grazing and highlight the importance of increased assessment and management of grazing behaviours for individuals with obesity and eating disorders. Plain English summary: Maintaining a healthy weight is one of the greatest challenges for individuals with obesity. Certain eating patterns such as grazing may contribute to difficulties in weight management. Grazing is the repetitive and unplanned eating of small amounts of food that is not related to feeling hungry. Researchers and clinicians often use self-report questionnaires to measure grazing. However, the first validated questionnaire of grazing has not been investigated among individuals with obesity. Therefore, the goal of this study was to examine and validate the Grazing Questionnaire in individuals with obesity. Overall, our results showed that the Grazing Questionnaire is a valid and reliable self-report measure of grazing in individuals with obesity. Similar to previous research, we found that there are two subtypes of grazing. The first subtype involves continuous, unplanned eating. The second subtype is associated with a sense of loss of control over eating. We also found that people with obesity and binge eating disorder graze more than people with obesity that do not have binge eating disorder, while both groups graze more than individuals with normal weight. We recommend that clinicians routinely assess and treat unhelpful grazing patterns when working with individuals with obesity and eating disorders
The changing pattern of domestic cannabis cultivation in the UK and its impact on the cannabis market
With improvements in both technology and information cannabis is being increasingly grown indoors for domestic use, rather than being imported. This study examines 50 cannabis farms detected by an English police force, and examines the characteristics of the 61 suspects associated with them. The study highlights a UK pattern in domestic cultivation, that is moving away from large scale commercial cultivation, at times co-ordinated by South East Asian organised crime groups, to increased cultivation within residential premises by British citizens. Offenders range from those who have no prior criminal history to those who are serious and persistent offenders. The ramifications for law enforcement agencies and policy formers are discussed
Examining the Seyfert - Starburst Connection with Arcsecond Resolution Radio Continuum Observations
We compare the arcsecond-scale circumnuclear radio continuum properties
between five Seyfert and five starburst galaxies, concentrating on the search
for any structures that could imply a spatial or causal connection between the
nuclear activity and a circumnuclear starburst ring. No evidence is found in
the radio emission for a link between the triggering or feeding of nuclear
activity and the properties of circumnuclear star formation. Conversely, there
is no clear evidence of nuclear outflows or jets triggering activity in the
circumnuclear rings of star formation. Interestingly, the difference in the
angle between the apparent orientation of the most elongated radio emission and
the orientation of the major axis of the galaxy is on average larger in
Seyferts than in starburst galaxies, and Seyferts appear to have a larger
physical size scale of the circumnuclear radio continuum emission. The
concentration, asymmetry, and clumpiness parameters of radio continuum emission
in Seyferts and starbursts are comparable, as are the radial profiles of radio
continuum and near-infrared line emission. The circumnuclear star formation and
supernova rates do not depend on the level of nuclear activity. The radio
emission usually traces the near-infrared Br-gamma and H2 1-0 S(1) line
emission on large spatial scales, but locally their distributions are
different, most likely because of the effects of varying local magnetic fields
and dust absorption and scattering.Comment: 21 pages, 10 figures. Accepted for publication in the Astronomical
Journa
Observations of the 6 Centimeter Lines of OH in Evolved (OH/IR) Stars
Recent observational and theoretical advances have called into question
traditional OH maser pumping models in evolved (OH/IR) stars. The detection of
excited-state OH lines would provide additional constraints to discriminate
amongst these theoretical models. In this Letter, we report on VLA observations
of the 4750 MHz and 4765 MHz lines of OH toward 45 sources, mostly evolved
stars. We detect 4765 MHz emission in the star forming regions Mon R2 and LDN
1084, but we do not detect excited-state emission in any evolved stars. The
flux density and velocity of the 4765 MHz detection in Mon R2 suggests that a
new flaring event has begun.Comment: 4 pages, to appear in ApJ
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