508 research outputs found
Detection of K+ mesons in segmented electromagnetic calorimeters
The combination of the CrystalBall and TAPS electromagnetic calorimeters were installed in the MAMI A2 hall in 2003. Here they are able to detect the reaction products from photo-induced reactions in combination with the Glasgow photon tagger. In the last two years the MAMI facility was upgraded from 885 MeV to 1.5 GeV, the A2 photon tagger underwent a similar upgrade crossing the threshold for strangeness photoproduction. For the CrystalBall this created a new challenge, to identify K+ mesons above the large background from other charged hadrons, in a situation where the detector setup does not benefit from a magnetic field to help separate particle species. These proceedings outline a novel technique which uses the decay products of the K+ as a strangeness tag
Novel acquisition strategies for dissolution dynamic nuclear polarisation
Dynamic Nuclear Polarisation (DNP) produced molecules with spin polarisation levels that are up to three orders of magnitude larger than their thermal equilibrium values. Most DNP mechanisms work at temperatures of 2 K and lower, meaning that the sample is stored in the solid-state. Combining DNP with a rapid temper- ature jump to room temperature allows liquid-state NMR analysis with a signal that is ve orders of magnitude higher than observed with thermal polarisation. However, the information obtained during a dissolution experiment is limited by the intrinsic liquid-state longitudinal relaxation of the spins of interest. is thesis looks to increase the information acquired in a number of ways. First, by devel- oping a new dissolution system for the dual iso-centre magnet it was possible to reproducibly perform enhanced NMR acquisition 600 ms following sample disso- lution. is has allowed the observation of hyperpolarised 13C spins with T1 times as low as 200 ms. Complimentary information can be obtained following sample dissolution by observing multiple spin species simultaneously. 13C and 15N spins are both polarised by microwave irradiation of the same frequency, so both can be analysed during a single dissolution DNP experiment. A novel probe has been used that contains six individual 13C microcoils. ese coils are separated in space and operate independently. is probe, in conjunction with dissolution DNP, can be used for observing dynamic molecular information on the time scale of 200 ms, however with further development this time scale should drop to less than 100 ms while maintaining a required minimum spectral resolution. Initial tests have been performed with both thermally polarised and hyperpolarised samples
Clustering and correlates of screen-time and eating behaviours among young adolescents
Background: Screen-time and eating behaviours are associated in adolescents, but few studies have examined the clustering of these health behaviours in this age group. The identification of clustered health behaviours, and influences on adolescents’ clustered health behaviours, at the time when they are most likely to become habitual, is important for intervention design. The purpose of this study was to assess the prevalence and clustering of health behaviours in adolescents, and examine the sociodemographic, individual, behavioural, and home social and physical environmental correlates of clustered health behaviours.
Methods: Adolescents aged 11–12 years (n=527, 48% boys) completed a questionnaire during class-time which assessed screen-time (ST), fruit and vegetable (FV), and energy-dense (ED) snack consumption using a Food Frequency Questionnaire. Health behaviours were categorised into high and low frequencies based on recommendations for FV and ST and median splits for ED snacks. Adolescents reported on their habits, self-efficacy, eating at the television (TV), eating and watching TV together with parents, restrictive parenting practices, and the availability and accessibility of foods within the home. Behavioural clustering was assessed using an observed over expected ratio (O/E). Correlates of clustered behaviours were examined using multivariate multinomial logistic regression.
Results: Approximately 70% reported having two or three health risk behaviours. Overall, O/E ratios were close to 1, which indicates clustering. The three risk behaviour combination of low FV, high ED, and high ST occurred more frequently than expected (O/E ratio = 1.06 95% CI 1.01, 1.15. Individual, behavioural, and social and physical home environmental correlates were differentially associated with behavioural clusters. Correlates consistently associated with clusters included eating ED snacks while watching TV, eating at the TV with parents, and the availability and accessibility of ED snack foods within the home.
Conclusions: There is a high prevalence of screen time and unhealthy eating, and screen time is coupled with unhealthy dietary behaviours. Strategies and policies are required that simultaneously address reductions in screen time and changes to habitual dietary patterns, such as TV snacking and snack availability and accessibility. These may require a combination of individual, social and environmental changes alongside conscious and more automatic (nudging) strategies
Novel acquisition strategies for dissolution dynamic nuclear polarisation
Dynamic Nuclear Polarisation (DNP) produced molecules with spin polarisation levels that are up to three orders of magnitude larger than their thermal equilibrium values. Most DNP mechanisms work at temperatures of 2 K and lower, meaning that the sample is stored in the solid-state. Combining DNP with a rapid temper- ature jump to room temperature allows liquid-state NMR analysis with a signal that is ve orders of magnitude higher than observed with thermal polarisation. However, the information obtained during a dissolution experiment is limited by the intrinsic liquid-state longitudinal relaxation of the spins of interest. is thesis looks to increase the information acquired in a number of ways. First, by devel- oping a new dissolution system for the dual iso-centre magnet it was possible to reproducibly perform enhanced NMR acquisition 600 ms following sample disso- lution. is has allowed the observation of hyperpolarised 13C spins with T1 times as low as 200 ms. Complimentary information can be obtained following sample dissolution by observing multiple spin species simultaneously. 13C and 15N spins are both polarised by microwave irradiation of the same frequency, so both can be analysed during a single dissolution DNP experiment. A novel probe has been used that contains six individual 13C microcoils. ese coils are separated in space and operate independently. is probe, in conjunction with dissolution DNP, can be used for observing dynamic molecular information on the time scale of 200 ms, however with further development this time scale should drop to less than 100 ms while maintaining a required minimum spectral resolution. Initial tests have been performed with both thermally polarised and hyperpolarised samples
Lecture capture: Practical recommendations for students and instructors
In this article, we provide practical recommendations to help promote self-regulated strategies for the use of lecture capture for both students and instructors. For students, we suggest that the importance of attendance and effective note-taking should be reinforced, as well as specifying how lecture capture can best be used as a catch-up or revision aid. For instructors, we highlight the need to provide guidance for students on how to learn and to adopt a context-dependent approach to lecture capture based on pedagogical considerations, rather than all-or-nothing. Regarding the issue of the relationship between lecture capture and attendance, we suggest the focus should move to a more nuanced discussion of why students fail to attend lectures and how they are using lecture capture. Finally, we discuss other concerns commonly raised by instructors related to lecture capture. Our student guidance is available for dissemination in infographic form at https://osf.io/esd2q/files/
Ancient Yersinia pestis and Salmonella enterica genomes from Bronze Age Crete
During the late 3rd millennium BCE, the Eastern Mediterranean and Near East witnessed societal changes in many regions, which are usually explained with a combination of social and climatic factors.1, 2, 3, 4 However, recent archaeogenetic research forces us to rethink models regarding the role of infectious diseases in past societal trajectories.5 The plague bacterium Yersinia pestis, which was involved in some of the most destructive historical pandemics,5, 6, 7, 8 circulated across Eurasia at least from the onset of the 3rd millennium BCE,9, 10, 11, 12, 13 but the challenging preservation of ancient DNA in warmer climates has restricted the identification of Y. pestis from this period to temperate climatic regions. As such, evidence from culturally prominent regions such as the Eastern Mediterranean is currently lacking. Here, we present genetic evidence for the presence of Y. pestis and Salmonella enterica, the causative agent of typhoid/enteric fever, from this period of transformation in Crete, detected at the cave site Hagios Charalambos. We reconstructed one Y. pestis genome that forms part of a now-extinct lineage of Y. pestis strains from the Late Neolithic and Bronze Age that were likely not yet adapted for transmission via fleas. Furthermore, we reconstructed two ancient S. enterica genomes from the Para C lineage, which cluster with contemporary strains that were likely not yet fully host adapted to humans. The occurrence of these two virulent pathogens at the end of the Early Minoan period in Crete emphasizes the necessity to re-introduce infectious diseases as an additional factor possibly contributing to the transformation of early complex societies in the Aegean and beyond.Results and discussion STAR★Method
Quasi-free Compton Scattering and the Polarizabilities of the Neutron
Differential cross sections for quasi-free Compton scattering from the proton
and neutron bound in the deuteron have been measured using the Glasgow/Mainz
tagging spectrometer at the Mainz MAMI accelerator together with the Mainz 48
cm 64 cm NaI(Tl) photon detector and the G\"ottingen SENECA
recoil detector. The data cover photon energies ranging from 200 MeV to 400 MeV
at . Liquid deuterium and hydrogen targets
allowed direct comparison of free and quasi-free scattering from the proton.
The neutron detection efficiency of the SENECA detector was measured via the
reaction . The "free" proton Compton scattering cross
sections extracted from the bound proton data are in reasonable agreement with
those for the free proton which gives confidence in the method to extract the
differential cross section for free scattering from quasi-free data.
Differential cross sections on the free neutron have been extracted and the
difference of the electromagnetic polarizabilities of the neutron have been
obtained to be
in units . In combination with the polarizability sum deduced from photoabsorption data, the neutron electric and
magnetic polarizabilities, and
are obtained. The backward spin polarizability of the neutron was determined to
be
Improving Community Health through Hospital-Public Health Collaboration: Insights and Lessons Learned from Successful Partnerships
From the introduction:
Health care expenditures in the United States currently consume over 17 percent of the nation’s gross domestic product, a much larger share than other developed nations. Yet, despite this large investment, studies by Commonwealth Fund, the Institute of Medicine, and other organizations show the USA lags behind other developed nations on multiple metrics of population health such as infant mortality and life expectancy. Moreover, there is extensive evidence of disparities in access, cost, and quality of health care services.
Thus, we are confronted by a striking paradox: the USA spends a large and growing proportion of our resources on health care, but the outcomes in terms of access to services, the quality of those services, and the health of our population do not match other countries whose spending per capita is lower. It is evident that many factors contribute to this paradox — demographic, environmental, genetic, lifestyle, and socioeconomic — and all warrant societal attention. Improving access to outpatient and inpatient medical services and the quality of those services, while important, cannot resolve the paradox.
Across the country, there is growing awareness that restraining the increase in health expenditures and improving the health status of families, communities, and society at large will require a broader approach that addresses the full array of factors affecting health status. Greater attention and resources must be devoted to promoting a safer environment, healthy lifestyles, prevention of illnesses and injuries, and early detection and treatment of health problems, as well as dealing with the underlying determinants of health. This approach necessitates integrating basic principles of public health into organizing and delivering health and medical services.https://uknowledge.uky.edu/hsm_book/1001/thumbnail.jp
Design and analysis of DLS steel/composite thick-adhernd adhesive joints
The paper describes experimental and numerical techniques to study the structural design and behaviourof thick-adherend DLS joints that are based on steel /steel and steel/composites and epoxy adhesives, withfocus on long overlap joints. A standard fabrication method was followed to produce 60 specimens of
various dimensions and materials
Three-nucleon mechanisms in photoreactions
The C reaction has been measured for
E=150-800 MeV in the first study of this reaction in a target
heavier than He. The experimental data are compared to a microscopic many
body calculation. The model, which predicts that the largest contribution to
the reaction arises from final state interactions following an initial pion
production process, overestimates the measured cross sections and there are
strong indications that the overestimate arises in this two-step process. The
selection of suitable kinematic conditions strongly suppresses this two-step
contribution leaving cross sections in which up to half the yield is predicted
to arise from the absorption of the photon on three interacting nucleons and
which agree with the model. The results indicate measurements on
nuclei may be a valuable tool for obtaining information on the nuclear
three-body interaction.Comment: 5 pages, 3 figure
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