2,299 research outputs found
A dynamic simulation of low-carbon policy influences on endogenous electricity demand in an isolated island system
This paper considers the dynamics of electricity demand in response to changes arising from low-carbon policies and socio-economic developments. As part of an investigation into the evolution of such systems on small economically-developed islands, endogenous electricity demand and associated policies are studied for the Azorean island of São Miguel. A comprehensive System Dynamics (SD) model covering the period 2005 − 2050 is presented which captures both historical behaviours and real-world influences on the endogenous demand dynamics of an island-based electricity system. The impact of tourism, energy efficiency and electric vehicles (EV) expansion allied with associated policy options, are critically evaluated by the SD model using a series of scenarios. The model shows that energy efficiency measures exhibit the most significant long-term impact on electricity demand, while in contrast, policies to increase tourism have a much less direct impact and EV expansion has thought-provoking impacts on the long-term demand, although this is not as influential as energy efficiency measures
Large-Scale Image Processing with the ROTSE Pipeline for Follow-Up of Gravitational Wave Events
Electromagnetic (EM) observations of gravitational-wave (GW) sources would
bring unique insights into a source which are not available from either channel
alone. However EM follow-up of GW events presents new challenges. GW events
will have large sky error regions, on the order of 10-100 square degrees, which
can be made up of many disjoint patches. When searching such large areas there
is potential contamination by EM transients unrelated to the GW event.
Furthermore, the characteristics of possible EM counterparts to GW events are
also uncertain. It is therefore desirable to be able to assess the statistical
significance of a candidate EM counterpart, which can only be done by
performing background studies of large data sets. Current image processing
pipelines such as that used by ROTSE are not usually optimised for large-scale
processing. We have automated the ROTSE image analysis, and supplemented it
with a post-processing unit for candidate validation and classification. We
also propose a simple ad hoc statistic for ranking candidates as more likely to
be associated with the GW trigger. We demonstrate the performance of the
automated pipeline and ranking statistic using archival ROTSE data. EM
candidates from a randomly selected set of images are compared to a background
estimated from the analysis of 102 additional sets of archival images. The
pipeline's detection efficiency is computed empirically by re-analysis of the
images after adding simulated optical transients that follow typical light
curves for gamma-ray burst afterglows and kilonovae. We show that the automated
pipeline rejects most background events and is sensitive to simulated
transients to limiting magnitudes consistent with the limiting magnitude of the
images
BCG Vaccination in HIV-Infected Children
Despite the use of Bacillus Calmette-Guérin (BCG) vaccination for many years, infants and young children exposed to adults with infectious forms of tuberculosis (TB) are at high risk of developing complicated TB disease. This risk is much higher among HIV-infected children, and data on BCG protective efficacy in HIV-infected children is lacking. Recent research on BCG safety in HIV-infected infants has resulted in policy shifts, but implementation is challenging. New approaches to preventing TB among infants and children, particularly HIV-infected infants, are needed. This paper briefly reviews BCG safety and efficacy considerations in HIV-infected infants and discusses other approaches to preventing TB, including new TB vaccines and vaccination strategies
A comparison of three outcome measures of the impact of vasomotor symptoms on women’s lives
Objective: Measures of the impact of vasomotor symptoms (VMS) have been used as outcomes in clinical trials but have not been compared. This study compares the Hot Flush Rating Scale (HFRS), the Hot Flash Related Daily Interference Scale (HFRDIS), and the shorter Hot Flash Interference (HFI) scale.Methods: Baseline data were taken from two studies including healthy women (menopause transition or postmenopause) and breast cancer patients experiencing VMS. Participants completed questionnaires on sociodemographics, the HFRS, the HFRDIS, the HFI, the Work and Social Adjustment Scale (WSAS), on depression (Generalized Anxiety Disorder 7), on anxiety (Patient Health Questionnaire 9), and on use of medical services.Results: A total of 169 women (129 with history of breast cancer and 40 without) aged 54.47 (standard deviation [SD] = 9.11) years took part. They had an average of 66 (SD = 40.94) VMS per week, with a mean HFRS problem-rating of 6.53 (SD = 1.99), HFRDIS score of 5.36 (SD = 2.22), and HFI score of 6.13 (SD = 2.30). The HFRS problem-rating, HFRDIS, and HFI were significantly associated (r = 0.61–0.85), had good internal reliability (α = 0.76–0.91), and had significant concurrent validity with mood, the WSAS, and use of medical services. VMS frequency was not associated with mood, the WSAS, or use of medical services.Conclusion: The HFRS problem-rating scale and the HFI are two brief, three-item measures that measure a similar concept of VMS interference/impact, with evidence of reliability and validity.</p
Effectiveness of new agri-environment schemes in conserving arable plants in intensively farmed landscapes
Electromagnetic follow-up of gravitational wave transient signal candidates
Pioneering efforts aiming at the development of multi-messenger gravitational
wave and electromagnetic astronomy have been made. An electromagnetic
observation follow-up program of candidate gravitational wave events has been
performed (Dec 17 2009 to Jan 8 2010 and Sep 4 to Oct 20 2010) during the
recent runs of the LIGO and Virgo gravitational wave detectors. It involved
ground-based and space electromagnetic facilities observing the sky at optical,
X-ray and radio wavelengths. The joint gravitational wave and electromagnetic
observation study requires the development of specific image analysis
procedures able to discriminate the possible electromagnetic counterpart of
gravitational wave triggers from contaminant/background events. The paper
presents an overview of the electromagnetic follow-up program and the image
analysis procedures.Comment: Proceedings of the 12th International Conference on "Topics in
Astroparticle and Underground Physics" (TAUP 2011), Munich, September 2011
(to appear in IoP Journal of Physics: Conference Series
Ground Motions Induced by the March 11, 2018, Implosion of the Capital Plaza Tower, Frankfort, Kentucky
The demolition by implosion of the Capital Plaza Tower in downtown Frankfort provided an opportunity to record seismic waves from a known source of seismic energy in order to observe local ground-motion amplification and resonance within the underlying unconsolidated sediment. The Kentucky Geological Survey deployed three strong-motion accelerographs at approximately equal distances around the tower to record ground motions induced by its collapse. The KGS instruments were installed at sites with different underlying geology: one on bedrock and two on Kentucky River Valley unconsolidated sediments.
Using images captured by a high-speed video camera, with timing synchronized with the clock of one of the strong-motion accelerographs, the sequence of ground-motion-inducing events from the tower demolition (blast explosions and the collapsing tower’s impact with the ground) was identified in the ground-motion time histories recorded at the rock site. This allowed the ground motions from the tower collapse recorded at all stations deployed for the event to be isolated and analyzed. The ground motions from the tower collapse recorded at the observation sites were weak and were likely imperceptible to humans. The detected motions, which had modified Mercalli intensities of only I to II at the rock and soil sites, respectively, were unlikely to have caused any damage there.
Seismic-wave resonance within the Kentucky River Valley sediment was identified from the analysis of these recordings. The resonance frequencies were similar at all KGS soil sites, and also were similar to those observed on seismographs deployed by the Energy and Environment Cabinet’s Explosives and Blasting Branch. These observations indicate that in the unlikely event of a nearby strong earthquake, shaking is expected to be amplified within the unconsolidated Kentucky River Valley sediments underlying downtown Frankfort
Pade approximants for functions with branch points - strong asymptotics of Nuttall-Stahl polynomials
Let f be a germ of an analytic function at infinity that can be analytically
continued along any path in the complex plane deprived of a finite set of
points, f \in\mathcal{A}(\bar{\C} \setminus A), \sharp A <\infty. J. Nuttall
has put forward the important relation between the maximal domain of f where
the function has a single-valued branch and the domain of convergence of the
diagonal Pade approximants for f. The Pade approximants, which are rational
functions and thus single-valued, approximate a holomorphic branch of f in the
domain of their convergence. At the same time most of their poles tend to the
boundary of the domain of convergence and the support of their limiting
distribution models the system of cuts that makes the function f single-valued.
Nuttall has conjectured (and proved for many important special cases) that this
system of cuts has minimal logarithmic capacity among all other systems
converting the function f to a single-valued branch. Thus the domain of
convergence corresponds to the maximal (in the sense of minimal boundary)
domain of single-valued holomorphy for the analytic function f
\in\mathcal{A}(\bar{\C} \setminus A). The complete proof of Nuttall's
conjecture (even in a more general setting where the set A has logarithmic
capacity zero) was obtained by H. Stahl. In this work, we derive strong
asymptotics for the denominators of the diagonal Pade approximants for this
problem in a rather general setting. We assume that A is a finite set of branch
points of f which have the algebraic character and which are placed in a
generic position. The last restriction means that we exclude from our
consideration some degenerated "constellations" of the branch points.Comment: 47 pages, 8 figure
Universal Window for Two Dimensional Critical Exponents
Two dimensional condensed matter is realised in increasingly diverse forms
that are accessible to experiment and of potential technological value. The
properties of these systems are influenced by many length scales and reflect
both generic physics and chemical detail. To unify their physical description
is therefore a complex and important challenge. Here we investigate the
distribution of experimentally estimated critical exponents, , that
characterize the evolution of the order parameter through the ordering
transition. The distribution is found to be bimodal and bounded within a window
, facts that are only in partial agreement with
the established theory of critical phenomena. In particular, the bounded nature
of the distribution is impossible to reconcile with existing theory for one of
the major universality classes of two dimensional behaviour - the XY model with
four fold crystal field - which predicts a spectrum of non-universal exponents
bounded only from below. Through a combination of numerical and renormalization
group arguments we resolve the contradiction between theory and experiment and
demonstrate how the "universal window" for critical exponents observed in
experiment arises from a competition between marginal operators.Comment: 26 pages, 5 figures and 6 tables. Uses longtable packag
- …