179,357 research outputs found
Breast feeding and resilience against psychosocial stress
BACKGROUND: Some early life exposures may result in a well controlled stress response, which can reduce stress related anxiety. Breast feeding may be a marker of some relevant exposures. AIMS: To assess whether breast feeding is associated with modification of the relation between parental divorce and anxiety. METHODS: Observational study using longitudinal birth cohort data. Linear regression was used to assess whether breast feeding modifies the association of parental divorce/separation with anxiety using stratification and interaction testing. Data were obtained from the 1970 British Cohort Study, which is following the lives of those born in one week in 1970 and living in Great Britain. This study uses information collected at birth and at ages 5 and 10 years for 8958 subjects. Class teachers answered a question on anxiety among 10 year olds using an analogue scale (range 0â50) that was log transformed to minimise skewness. RESULTS: Among 5672 nonâbreast fed subjects, parental divorce/separation was associated with a statistically significantly raised risk of anxiety, with a regression coefficient (95% CI) of 9.4 (6.1 to 12.8). Among the breast fed group this association was much lower: 2.2 (â2.6 to 7.0). Interaction testing confirmed statistically significant effect modification by breast feeding, independent of simultaneous adjustment for multiple potential confounding factors, producing an interaction coefficient of â7.0 (â12.8 to â1.2), indicating a 7% reduction in anxiety after adjustment. CONCLUSIONS: Breast feeding is associated with resilience against the psychosocial stress linked with parental divorce/separation. This could be because breast feeding is a marker of exposures related to maternal characteristics and parentâchild interaction
Relating harmonic and projective descriptions of N=2 nonlinear sigma models
Recent papers have established the relationship between projective superspace
and a complexified version of harmonic superspace. We extend this construction
to the case of general nonlinear sigma models in both frameworks. Using an
analogy with Hamiltonian mechanics, we demonstrate how the Hamiltonian
structure of the harmonic action and the symplectic structure of the projective
action naturally arise from a single unifying action on a complexified version
of harmonic superspace. This links the harmonic and projective descriptions of
hyperkahler target spaces. For the two examples of Taub-NUT and Eguchi-Hanson,
we show how to derive the projective superspace solutions from the harmonic
superspace solutions.Comment: 25 pages; v3: typo fixed in eq (1.36
Three-dimensional (p,q) AdS superspaces and matter couplings
We introduce N-extended (p,q) AdS superspaces in three space-time dimensions,
with p+q=N and p>=q, and analyse their geometry. We show that all (p,q) AdS
superspaces with X^{IJKL}=0 are conformally flat. Nonlinear sigma-models with
(p,q) AdS supersymmetry exist for p+q4 the target space geometries
are highly restricted). Here we concentrate on studying off-shell N=3
supersymmetric sigma-models in AdS_3. For each of the cases (3,0) and (2,1), we
give three different realisations of the supersymmetric action. We show that
(3,0) AdS supersymmetry requires the sigma-model to be superconformal, and
hence the corresponding target space is a hyperkahler cone. In the case of
(2,1) AdS supersymmetry, the sigma-model target space must be a non-compact
hyperkahler manifold endowed with a Killing vector field which generates an
SO(2) group of rotations of the two-sphere of complex structures.Comment: 52 pages; V3: minor corrections, version published in JHE
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Impact of void ratio and state parameters on the small strain shear modulus of unsaturated soils
Extended supersymmetric sigma models in AdS_4 from projective superspace
There exist two superspace approaches to describe N=2 supersymmetric
nonlinear sigma models in four-dimensional anti-de Sitter (AdS_4) space: (i) in
terms of N=1 AdS chiral superfields, as developed in arXiv:1105.3111 and
arXiv:1108.5290; and (ii) in terms of N=2 polar supermultiplets using the AdS
projective-superspace techniques developed in arXiv:0807.3368. The virtue of
the approach (i) is that it makes manifest the geometric properties of the N=2
supersymmetric sigma-models in AdS_4. The target space must be a non-compact
hyperkahler manifold endowed with a Killing vector field which generates an
SO(2) group of rotations on the two-sphere of complex structures. The power of
the approach (ii) is that it allows us, in principle, to generate hyperkahler
metrics as well as to address the problem of deformations of such metrics.
Here we show how to relate the formulation (ii) to (i) by integrating out an
infinite number of N=1 AdS auxiliary superfields and performing a superfield
duality transformation. We also develop a novel description of the most general
N=2 supersymmetric nonlinear sigma-model in AdS_4 in terms of chiral
superfields on three-dimensional N=2 flat superspace without central charge.
This superspace naturally originates from a conformally flat realization for
the four-dimensional N=2 AdS superspace that makes use of Poincare coordinates
for AdS_4. This novel formulation allows us to uncover several interesting
geometric results.Comment: 88 pages; v3: typos corrected, version published in JHE
Microscopic origin of the optical processes in blue sapphire
Al2O3 changes from transparent to a range of intense colours depending on the chemical impurities present. In blue sapphire, Fe and Ti are incorporated; however, the chemical process that gives rise to the colour has long been debated. Atomistic modelling identifies charge transfer from Ti(III) to Fe(III) as being responsible for the characteristic blue appearance
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Echo state network for occupancy prediction and pattern mining in intelligent environment
Pattern analysis and prediction of sensory data is becoming an increasing scientific challenge and a massive economical interest supports the need for better pattern mining techniques. The aim of this paper is to investigate efficient mining of useful information from a sensor network representing an ambient intelligence environment. The goal is to extract and predict behavioral patterns of a person in his/her daily activities by analyzing the time series data representing the behaviour of the occupant, generated using occupancy sensors. There are various techniques available for analysis and prediction of a continuous time series signal. However, the occupancy signal is represented by a binary time series where only discrete values of a signal are available. To build the prediction model, recurrent neural networks are investigated. They are proven to be useful tools to solve the difficulties of the temporal relationships of inputs between observations at different time steps, by maintaining internal states that have memory. In this paper, a special form of recurrent neural network, the so-called Echo State Network (ESN) is used in which discrete values of time series can be well processed. Then, a model developed based on ESN is compared with the most popular recurrent neural net-works; namely Back Propagation Through Time (BPTT) and Real Time Recurrent Learning (RTRL). The results showed that ESN provides better prediction results compared with BPTT and RTRL. Using ESN, large datasets are learnt in only few minutes or even seconds. It can be concluded that ESN are efficient and valuable tools in binary time series prediction. The results presented in this paper are based on simulated data generated from a simulator representing a person in a 1 bedroom flat
Educational Ethics in Academic Environment: Medical Students' Perspectives
Background and Objective: Educational ethics imply values such as honesty, reliance on one's own personal
effort, not to abuse the efforts of others, and respect the dignity and respect for others. Students are faced
with different situations in which they show various moral and immoral behaviors. This study aimed to
explore medical students' viewpoints and experiences at Golestan University of Medical Sciences about
ethics in academic environment in 2013.
Materials and Methods: In this qualitative study a purposive sampling was used with maximum variation
and 12 medical students participated in the research. Data was gathered using semi-structured interviews. At
least an open question "When I say ethics in education or educational environment, what comes to your
mind" was repeated in all the interviews. The interviews recorded and transcribed line by line and then
analyzed according to "conventional content analysis" method.
Results: "Respecting teacher dignity", "preserving dignity of classroom", "respecting and maintaining
dignity for classmates", "seeking for knowledge and sciencesâ emerged as the main themes of the current
study.
Conclusion: University students considered learning environment as a sacred place; conforming its expected
rules and ethics would be mandatory. Abnormal behavior causes not only loss of students dignity but also
could be harmful to the calmness of educational atmosphere and may evoke different unpleasant pessimistic
ideas about such academic environment
âIt's like the bad guy in a movie who just doesn't dieâ : a qualitative exploration of young people's adaptation to eczema and implications for selfâcare
Background
Eczema is a common childhood inflammatory skin condition, affecting more than one in five children. A popular perception is that children âoutgrow eczemaâ, although epidemiological studies have shown that, for many, eczema follows a lifelong episodic course.
Objectives
To explore the perceptions of young people about the nature of their eczema and how these perceptions relate to their selfâcare and adapting to living with eczema.
Methods
This is a secondary inductive thematic analysis of interviews conducted for Healthtalk.org. In total 23 interviews with young people with eczema were included. Of the 23 participants, 17 were female and six male, ranging from 17 to 25 years old.
Results
Participants generally experienced eczema as an episodic longâterm condition and reported a mismatch between information received about eczema and their experiences. The experience of eczema as long term and episodic had implications for selfâcare, challenging the process of identifying triggers of eczema flareâups and evaluating the success of treatment regimens. Participantsâ experiences of eczema over time also had implications for adaptation and finding a balance between accepting eczema as long term and hoping it would go away. This linked to a gradual shift in treatment expectations from âcureâ to âcontrolâ of eczema.
Conclusions
For young people who continue to experience eczema beyond childhood, a greater focus on selfâcare for a longâterm condition may be helpful. Greater awareness of the impact of early messages around âgrowing out ofâ eczema and provision of highâquality information may help patients to manage expectations and support adaptation to treatment regimens
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