3,774 research outputs found
Field condensations and Noncritical String for c>1
Quantum theory of 2d gravity for is examined as a non-critical string
theory by taking account of the loop-correction of open strings whose end
points are on the 2d world surface of the closed string. This loop-correction
leads to a conformal anomaly, and we obtain a modified target-space action
which implies a new phase of the non-critical closed-string. In this phase, the
dual field of the gauge field, which lives on the boundary, condenses and the
theory can be extended to without any instability.Comment: 17 pages, Latex, no figur
Phase Transitions of Single Semi-stiff Polymer Chains
We study numerically a lattice model of semiflexible homopolymers with
nearest neighbor attraction and energetic preference for straight joints
between bonded monomers. For this we use a new algorithm, the "Pruned-Enriched
Rosenbluth Method" (PERM). It is very efficient both for relatively open
configurations at high temperatures and for compact and frozen-in low-T states.
This allows us to study in detail the phase diagram as a function of
nn-attraction epsilon and stiffness x. It shows a theta-collapse line with a
transition from open coils to molten compact globules (large epsilon) and a
freezing transition toward a state with orientational global order (large
stiffness x). Qualitatively this is similar to a recently studied mean field
theory (Doniach et al. (1996), J. Chem. Phys. 105, 1601), but there are
important differences. In contrast to the mean field theory, the
theta-temperature increases with stiffness x. The freezing temperature
increases even faster, and reaches the theta-line at a finite value of x. For
even stiffer chains, the freezing transition takes place directly without the
formation of an intermediate globule state. Although being in contrast with
mean filed theory, the latter has been conjectured already by Doniach et al. on
the basis of low statistics Monte Carlo simulations. Finally, we discuss the
relevance of the present model as a very crude model for protein folding.Comment: 11 pages, Latex, 8 figure
Confidential Boosting with Random Linear Classifiers for Outsourced User-generated Data
User-generated data is crucial to predictive modeling in many applications.
With a web/mobile/wearable interface, a data owner can continuously record data
generated by distributed users and build various predictive models from the
data to improve their operations, services, and revenue. Due to the large size
and evolving nature of users data, data owners may rely on public cloud service
providers (Cloud) for storage and computation scalability. Exposing sensitive
user-generated data and advanced analytic models to Cloud raises privacy
concerns. We present a confidential learning framework, SecureBoost, for data
owners that want to learn predictive models from aggregated user-generated data
but offload the storage and computational burden to Cloud without having to
worry about protecting the sensitive data. SecureBoost allows users to submit
encrypted or randomly masked data to designated Cloud directly. Our framework
utilizes random linear classifiers (RLCs) as the base classifiers in the
boosting framework to dramatically simplify the design of the proposed
confidential boosting protocols, yet still preserve the model quality. A
Cryptographic Service Provider (CSP) is used to assist the Cloud's processing,
reducing the complexity of the protocol constructions. We present two
constructions of SecureBoost: HE+GC and SecSh+GC, using combinations of
homomorphic encryption, garbled circuits, and random masking to achieve both
security and efficiency. For a boosted model, Cloud learns only the RLCs and
the CSP learns only the weights of the RLCs. Finally, the data owner collects
the two parts to get the complete model. We conduct extensive experiments to
understand the quality of the RLC-based boosting and the cost distribution of
the constructions. Our results show that SecureBoost can efficiently learn
high-quality boosting models from protected user-generated data
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Enabling mothers of young children in a low SES area to co-design the support they are seeking for the adoption of healthy behaviours
Aims:
There is a need for interventions that meet the needs of low socioeconomic status (SES) groups, to encourage the adoption of healthy diets and physical activity, in line with current public health guidance. This qualitative research used co-production, a method which actively involves the relevant community, to identify and describe public health interventions to support a group of mothers of young children living in a low SES area.
Methods:
A group of 20 mothers took part in three in-depth qualitative interviews to discuss in detail the type of support that would be of value to them for the adoption and maintenance of healthy behaviours. The mothers were subsequently invited to take part in a public engagement project, a community-based self-help group.
Results:
Four themes explained the principles of interventions that would be of value in supporting the mothers with the adoption of healthy behaviours, namely, a community-based self-help group, support for the whole family and support in the home and influencing the environment. These were then further developed into two types of intervention (1) learning for self-help and family care, which encompassed the first three learning-based themes and (2) community of support, which covered influencing the environment and the experience of the community-based self-help group.
Conclusion:
Co-production enabled a group of mothers of young children, from a low SES area, to describe the type of support that would help them with the establishment and maintenance of healthy lifestyle behaviours. A community-based self-help group warrants further research.The Annette Lawson (AL) Charitable Trust awarded £600 for particpants involvement in interveiws. Brunel University London College of Health and Life Sciences awarded £200 for involvement in interview three. A further £1,909 was received from the Brunel University London Public Engagement Fund
Adopting and maintaining a healthy lifestyle in low SES families: How the experience of motherhood shapes responses to dietary and physical activity public health guidance
Availability of data and materials: The data that support the findings of this study are available in the PhD thesis, Wittels PY Shaping health: understanding and influencing lifestyle behaviours in low socioeconomic women, Brunel University London, 2021 https://bura.brunel.ac.uk/bitstream/2438/21644/1/FulltextThesis.pdf.The Annette Lawson (AL) Charitable Trust made an award of £600 with the funds being used to recognise the time the participants gave to the interviews. Brunel University College of Health and Life Sciences made an award of an additional £200 to make payments to the participants for the third interviews
The Family Is My Priority: How Motherhood Frames Participation in Physical Activity in a Group of Mothers Living in a Low Socioeconomic Status Area
Copyright: © 2022 by the authors. Socioeconomic status (SES) is known to influence strongly both life expectancy and healthy life expectancy. Whilst there are multiple factors with complex interactions that provide the explanation for this observation, differences in the uptake of physical activity between high and low SES groups play a role. This in-depth qualitative study set out to understand the response of a group of mothers with young children living in a low SES area of a London (UK) borough to the current physical activity guidance and to investigate whether existing and established interventions based on behavior change are appropriate for this group. A series of three in depth interviews was carried out with the mothers (n = 20) over a period of 16 months, and the data collected were analyzed thematically. Four main themes were identified: (1) mothering comes before exercise; (2) mothers are a special case; (3) alone or together; and (4) facilities fail mothers. The mothers were unsure about the benefits of exercise, whether it was relevant for them and how to accommodate exercise alongside their mothering responsibilities. Family and peer group could be both a barrier and a facilitator to participation in physical activity. Without an in depth understanding of the role of physical activity in the lives of mothers of young children, behavior change-based public interventions are likely to fail to meet the needs of this group. A reduction in the current health inequities will only be possible when the needs of the mothers are acknowledged and used as the basis of appropriate public health guidance.The Annette Lawson (AL) Charitable Trust; Brunel University London, College of Health and Life Sciences
VetCompass Australia: A National Big Data Collection System for Veterinary Science
VetCompass Australia is veterinary medical records-based research coordinated with the global VetCompass endeavor to maximize its quality and effectiveness for Australian companion animals (cats, dogs, and horses). Bringing together all seven Australian veterinary schools, it is the first nationwide surveillance system collating clinical records on companion-animal diseases and treatments. VetCompass data service collects and aggregates real-time, clinical records for researchers to interrogate, delivering sustainable and cost-effective access to data from hundreds of veterinary practitioners nationwide. Analysis of these clinical records will reveal geographical and temporal trends in the prevalence of inherited and acquired diseases, identify frequently prescribed treatments, revolutionize clinical auditing, help the veterinary profession to rank research priorities, and assure evidence-based companion-animal curricula in veterinary schools. VetCompass Australia will progress in three phases: (1) roll-out of the VetCompass platform to harvest Australian veterinary clinical record data; (2) development and enrichment of the coding (data-presentation) platform; and (3) creation of a world-first, real-time surveillance interface with natural language processing (NLP) technology. The first of these three phases is described in the current article. Advances in the collection and sharing of records from numerous practices will enable veterinary professionals to deliver a vastly improved level of care for companion animals that will improve their quality of life
Absolute photoionization cross section measurements of the Kr I-isoelectronic sequence
Photoionization spectra have been recorded in the 4s, 4p and 3d resonance regions for the Kr Iisoelectronic sequence using both the dual laser produced plasma technique (at DCU) to produce photoabsorption spectra, and the merged ion beam and synchrotron radiation technique (at ASTRID) to measure absolute photoionization cross sections. Profile parameters are compared for the 4s − np resonances of Rb+ and Sr2+. Many new 4p " ns, md transitions are identified with the aid of Hartree-Fock calculations, and consistent quantum defects are observed for the various ns and md Rydberg series. Absolute single and double photoionization cross sections recorded in the 3d region for Rb+ and Sr2+ ions show preferential decay via double photoionization. This is only the second report where both the DLP technique and the merged beam technique have been used simultaneously to record photoionization spectra, and the advantages of both techniques (i.e. better resolution in the case of DLP and values for absolute photoionization cross sections in the case of the merged beam technique) are highlighted
Registered report: the impact of the COVID-19 pandemic on adolescent mental health: a natural experiment
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