81 research outputs found
Axion detection in the milli-eV mass range
We propose an experimental scheme to search for galactic halo axions with
mass eV, which is above the range accessible with cavity
techniques. The detector consists of a large number of parallel superconducting
wires embedded in a material transparent to microwave radiation. The wires
carry a current configuration which produces a static, inhomogeneous magnetic
field within the detector volume. Axions which enter this
volume may convert to photons. We discuss the feasibility of the detector and
its sensitivity.Comment: LaTex, 9 pages, 4 figures (sent upon request), UFIFT-HEP-93--
Studies of the motion and decay of axion walls bounded by strings
We discuss the appearance at the QCD phase transition, and the subsequent
decay, of axion walls bounded by strings in N=1 axion models. We argue on
intuitive grounds that the main decay mechanism is into barely relativistic
axions. We present numerical simulations of the decay process. In these
simulations, the decay happens immediately, in a time scale of order the light
travel time, and the average energy of the radiated axions is for . is found to increase
approximately linearly with . Extrapolation of this behaviour
yields in axion models of interest. We find that the
contribution to the cosmological energy density of axions from wall decay is of
the same order of magnitude as that from vacuum realignment, with however large
uncertainties. The velocity dispersion of axions from wall decay is found to be
larger, by a factor or so, than that of axions from vacuum realignment
and string decay. We discuss the implications of this for the formation and
evolution of axion miniclusters and for the direct detection of axion dark
matter on Earth. Finally we discuss the cosmology of axion models with in
which the domain wall problem is solved by introducing a small U(1)
breaking interaction. We find that in this case the walls decay into
gravitational waves.Comment: 37 pages, 10 figures, a minor mistake was corrected, several
references and comments were adde
Relationship-based Practice with Families Where Child Neglect is an Issue: Putting Relationship Development under the Microscope
Detection of unsafety in families with parental and/or child developmental problems at the start of family support
Background Risk assessment is crucial in preventing child maltreatment as it can identify high-risk cases in need of child protection intervention. Despite this importance, there have been no validated risk assessment instruments available in the Netherlands for assessing the risk of child maltreatment. Therefore, the predictive validity of the California Family Risk Assessment (CFRA) was examined in Dutch families who received family support. In addition, the added value of a number of experimental items was examined. Finally, it was examined whether the predictive value of the instrument could be improved by modifying the scoring procedure. Methods Dutch families who experienced parenting and/or child developmental problems and were referred by the Centres for Youth and Family for family support between July 2009 and March 2011 were included. This led to a sample of 491 families. The predictive validity of the CFRA and the added value of the experimental items were examined by calculating AUC values. A CHAID analysis was performed to examine whether the scoring procedure could be improved. Results About half of the individual CFRA items were not related to future reports of child maltreatment. The predictive validity of the CFRA in predicting future reports of child maltreatment was found to be modest (AUC = .693). The addition of some of the experimental items and the modification of the scoring procedure by including only items that were significantly associated with future maltreatment reports resulted in a ‘high’ predictive validity (AUC = .795). Conclusions This new set of items might be a valuable instrument that also saves time because only variables that uniquely contribute to the prediction of future reports of child maltreatment are included. Furthermore, items that are perceived as difficult to assess by professionals, such as parental mental health problems or parents’ history of abuse/neglect, could be omitted without compromising predictive validity. However, it is important to examine the psychometric properties of this new set of items in a new dataset
Constraints on Very Light Axions from Cavity Experiments
In view of the ongoing galactic (or cosmic) axion detection experiments, we
compare the axion-photon-photon coupling 's for various
invisible (or very light) axion models.Comment: LaTeX, 1 eps figure include
Detection of unsafety in families with parental and/or child developmental problems at the start of family support
How Did I Know When to Report Physical Neglect? Ghanaian Mothers’ Views on Delinquent Child Maintenance
Predicting Program Completion Among Families Enrolled in a Child Neglect Preventive Intervention
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