20,808 research outputs found
Photometry of 40 LMC Cepheids
We present V and I_c CCD photometry for 40 LMC Cepheids at 1 to 3 epochs.
This represents a significant increase in the number of LMC Cepheids with
-band data, and, as we show, is a useful addition to the sample which can be
used to calibrate the period--luminosity relations in these important bands
Changing atmospheric Δ^(14)C and the record of deep water paleoventilation ages
We propose a new calculation method to better estimate the deep water ventilation age from benthic-planktonic foraminifera ^(14)C ages. Our study is motivated by the fact that changes in atmospheric Δ^(14)C through time can cause contemporary benthic and planktonic foraminifera to have different initial Δ^(14)C values. This effect can cause spurious ventilation age changes to be interpreted from the geologic data. Using a new calculation method, ^(14)C projection ages, we recalculate the data from the Pacific Ocean. Contrary to previous results, we find that the Pacific intermediate and deep waters were about 600 years older than today at the last glacial maximum. In addition, there are possible signals of ventilation age change prior to ice sheet melting and at the Younger Dryas. However, the data are still too sparse to constrain these ventilation transients
Decentering, perspective broadening and anxiety
Section A
Theorists have long suggested that the process of decentering may be linked to anxiety. This paper reviewed empirical studies to explore what, if any, relationship existed between decentering and anxiety. A systematic search yielded 16 papers that met inclusion criteria. Studies included were a range of cross-sectional design with simple and multi-variant associations; longitudinal design; causal-comparative design; and intervention designs. The review found good evidence from studies of sufficient quality to the conclusion that there is a negative association between decentering and anxiety. Evidence was not found for further comment on the nature of the relationship. Research that directly targets decentering as an independent variable while measuring anxiety as the dependent variable is one of the recommendations of this review.
Section B
Anxiety presentations remain the most prevalent mental health condition and are associated with poor quality of life as well as an immense health care costs to the NHS. Transdiagnostic approaches that target the mechanisms of change in established therapies offer promise in developing briefer, more targeted interventions and have the potential to be applied across mental health presentations. The STAGE approach was developed as a two-step technique to directly target decentering and perspective broadening, hypothesised active ingredients of CBT and mindfulness therapies. This study sought to use a pilot and feasibility design to explore a new brief online self-help format of STAGE for those with self-reported anxiety. Overall, the STAGE programme was found to be mostly acceptable to participants. Additionally, trends and preliminary data were tentatively encouraging. However, attrition rates were considerable, and it was considered unfeasible to recruit and run a full-scale randomised control trial (RCT) without further adaptations to the STAGE format. Study limitations are discussed as are the implications for theory, research and clinical practice
Do Quasars Lens Quasars?
If the unexpectedly high frequency of quasar pairs with very different
component redshifts is due to the lensing of a population of background quasars
by the foreground quasar, typical lens masses must be \sim10^{12}M_{\sun} and
the sum of all such quasar lenses would have to contain times the
closure density of the Universe. It then seems plausible that a very high
fraction of all \sim10^{12} M_{\sun} gravitational lenses with redshifts
contain quasars. Here I propose that these systems have evolved to
form the present population of massive galaxies with M and M
>5\times10^{11} M_{\sun}.Comment: 6 pages, aas style, ams symbols, ApJL (accepted
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