329 research outputs found
The scientific potential of space-based gravitational wave detectors
The millihertz gravitational wave band can only be accessed with a
space-based interferometer, but it is one of the richest in potential sources.
Observations in this band have amazing scientific potential. The mergers
between massive black holes with mass in the range 10 thousand to 10 million
solar masses, which are expected to occur following the mergers of their host
galaxies, produce strong millihertz gravitational radiation. Observations of
these systems will trace the hierarchical assembly of structure in the Universe
in a mass range that is very difficult to probe electromagnetically. Stellar
mass compact objects falling into such black holes in the centres of galaxies
generate detectable gravitational radiation for several years prior to the
final plunge and merger with the central black hole. Measurements of these
systems offer an unprecedented opportunity to probe the predictions of general
relativity in the strong-field and dynamical regime. Millihertz gravitational
waves are also generated by millions of ultra-compact binaries in the Milky
Way, providing a new way to probe galactic stellar populations. ESA has
recognised this great scientific potential by selecting The Gravitational
Universe as its theme for the L3 large satellite mission, scheduled for launch
in ~2034. In this article we will review the likely sources for millihertz
gravitational wave detectors and describe the wide applications that
observations of these sources could have for astrophysics, cosmology and
fundamental physics.Comment: 18 pages, 2 figures, contribution to Gravitational Wave Astrophysics,
the proceedings of the 2014 Sant Cugat Forum on Astrophysics; v2 includes one
additional referenc
The evolution of Palaeolake Flixton and the environmental context of Star Carr:An oxygen and carbon isotopic record of environmental change for the early Holocene
This paper presents δ18O and δ13C values from three early Holocene lacustrine carbonate sequences from Palaeolake Flixton in northeastern England. The δ13C values are typical of carbonates precipitating in an open lake system with the exception of samples from the very uppermost parts of these sequences which have values more typical of palustrine or tufaceous carbonates and, therefore, indicate the progressive contraction and shrinkage of the lake system overtime. The δ18O values record an initial increase to an early peak at the onset of the Holocene but a subsequent decline in values of such a magnitude that by ca 8000 yrs B.P. the δ18O value of the precipitated carbonate is consistent with carbonates that precipitated at the end of the Loch Lomond Stadial. The early increase and peak in δ18O values is suggested to reflect the climatic amelioration at the onset of the Holocene, as temperatures progressively rose. The decline cannot be explained by any known temperature shifts, however, this “depletion trend” is seen in several other early Holocene lacustrine records from across the British Isles. This decline is suggested to reflect a shift in the seasonality of precipitation from a more seasonal precipitation regime typical of a “continental” climate, with strong seasonal contrasts in rainfall, to a more “maritime” climate which was characterised by consistent levels of rainfall occurring across the year. The relative timing of human activity at Star Carr suggests human occupation occurred after this isotopic decline under “maritime” rather than “continental” climates
Implicit measures of association in psychopathology research
Studies obtaining implicit measures of associations in Diagnostic and Statistical Manual of Mental Disorders (4th ed., Text Revision; American Psychiatric Association, 2000) Axis I psychopathology are organized into three categories: (a) studies comparing groups having a disorder with controls, (b) experimental validity studies, and (c) incremental and predictive validity studies. In the first category, implicit measures of disorder-relevant associations were consistent with explicit beliefs for some disorders (e.g., specific phobia), but for other disorders evidence was either mixed (e.g., panic disorder) or inconsistent with explicit beliefs (e.g., pain disorder). For substance use disorders and overeating, expected positive and unexpected negative associations with craved substances were found consistently. Contrary to expectation, implicit measures of self-esteem were consistently positive for patients with depressive disorder, social phobia, and body dysmorphic disorder. In the second category, short-term manipulations of disorder-relevant states generally affected implicit measures as expected. Therapeutic interventions affected implicit measures for one type of specific phobia, social phobia, and panic disorder, but not for alcohol use disorders or obesity. In the third category, implicit measures had predictive value for certain psychopathological behaviors, sometimes moderated by the availability of cognitive resources (e.g., for alcohol and food, only when cognitive resources were limited). The strengths of implicit measures include (a) converging evidence for dysfunctional beliefs regarding certain disorders and consistent new insights for other disorders and (b) prediction of some psychopathological behaviors that explicit measures cannot explain. Weaknesses include (a) that findings were inconsistent for some disorders, raising doubts about the validity of the measures, and (b) that understanding of the concept "implicit" is incomplete
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Interaction of convective organisation with monsoon precipitation, atmosphere, surface and sea: the 2016 INCOMPASS field campaign in India
The INCOMPASS field campaign combines airborne and ground measurements of the 2016 Indian monsoon, towards the ultimate goal of better predicting monsoon rainfall. The monsoon supplies the majority of water in South Asia, but forecasting from days to the season ahead is limited by large, rapidly developing errors in model parametrizations. The lack of detailed observations prevents thorough understanding of the monsoon circulation and its interaction with the land surface: a process governed by boundary‐layer and convective‐cloud dynamics. INCOMPASS used the UK Facility for Airborne Atmospheric Measurements (FAAM) BAe‐146 aircraft for the first project of this scale in India, to accrue almost 100 h of observations in June and July 2016. Flights from Lucknow in the northern plains sampled the dramatic contrast in surface and boundary‐layer structures between dry desert air in the west and the humid environment over the northern Bay of Bengal. These flights were repeated in pre‐monsoon and monsoon conditions. Flights from a second base at Bengaluru in southern India measured atmospheric contrasts from the Arabian Sea, over the Western Ghats mountains, to the rain shadow of southeast India and the south Bay of Bengal. Flight planning was aided by forecasts from bespoke 4 km convection‐permitting limited‐area models at the Met Office and India's NCMRWF. On the ground, INCOMPASS installed eddy‐covariance flux towers on a range of surface types, to provide detailed measurements of surface fluxes and their modulation by diurnal and seasonal cycles. These data will be used to better quantify the impacts of the atmosphere on the land surface, and vice versa. INCOMPASS also installed ground instrumentation supersites at Kanpur and Bhubaneswar. Here we motivate and describe the INCOMPASS field campaign. We use examples from two flights to illustrate contrasts in atmospheric structure, in particular the retreating mid‐level dry intrusion during the monsoon onset
Beyond the Regional Average: Drivers of Geographical Rainfall Variability during East Africa’s Short Rains
The East African “short rains” from October–December (OND) are crucial for the region's cultural and agricultural landscape. Traditional climate studies have often treated these rains as a single mode, representing the average rainfall across the region. This approach, however, fails to capture the complex geographical variations in seasonal rainfall. In our study, we analyse 4200 reforecasts from a seasonal prediction system spanning 1981–2022, identifying distinct clusters that represent different geographical patterns of the short rains. We explore the influence of tropical sea-surface temperature patterns, upper-level tropospheric flow, and low-level moisture fluxes on these clusters. A key revelation of our research is the limited predictability of certain geographical rainfall structures based on large-scale climatic drivers. This finding highlights a gap in current forecasting methodologies, emphasising the necessity for further research to understand and predict these intricate patterns. Our study illuminates the complexities of regional rainfall variability in East Africa, underlining the importance of continued investigation to improve climate resilience strategies in the region
Measurement of the Bottom-Strange Meson Mixing Phase in the Full CDF Data Set
We report a measurement of the bottom-strange meson mixing phase \beta_s
using the time evolution of B0_s -> J/\psi (->\mu+\mu-) \phi (-> K+ K-) decays
in which the quark-flavor content of the bottom-strange meson is identified at
production. This measurement uses the full data set of proton-antiproton
collisions at sqrt(s)= 1.96 TeV collected by the Collider Detector experiment
at the Fermilab Tevatron, corresponding to 9.6 fb-1 of integrated luminosity.
We report confidence regions in the two-dimensional space of \beta_s and the
B0_s decay-width difference \Delta\Gamma_s, and measure \beta_s in [-\pi/2,
-1.51] U [-0.06, 0.30] U [1.26, \pi/2] at the 68% confidence level, in
agreement with the standard model expectation. Assuming the standard model
value of \beta_s, we also determine \Delta\Gamma_s = 0.068 +- 0.026 (stat) +-
0.009 (syst) ps-1 and the mean B0_s lifetime, \tau_s = 1.528 +- 0.019 (stat) +-
0.009 (syst) ps, which are consistent and competitive with determinations by
other experiments.Comment: 8 pages, 2 figures, Phys. Rev. Lett 109, 171802 (2012
Astronomical Distance Determination in the Space Age: Secondary Distance Indicators
The formal division of the distance indicators into primary and secondary leads to difficulties in description of methods which can actually be used in two ways: with, and without the support of the other methods for scaling. Thus instead of concentrating on the scaling requirement we concentrate on all methods of distance determination to extragalactic sources which are designated, at least formally, to use for individual sources. Among those, the Supernovae Ia is clearly the leader due to its enormous success in determination of the expansion rate of the Universe. However, new methods are rapidly developing, and there is also a progress in more traditional methods. We give a general overview of the methods but we mostly concentrate on the most recent developments in each field, and future expectations. © 2018, The Author(s)
Protein turnover in acid maltase deficiency before and after treatment with a high protein diet.
Models of peer support to remediate post-intensive care syndrome: A report developed by the SCCM Thrive International Peer Support Collaborative
Objective: Patients and caregivers can experience a range of physical, psychological, and
cognitive problems following critical care discharge. The use of peer support has been
proposed as an innovative support mechanism.
Design: We sought to identify technical, safety and procedural aspects of existing
operational models of peer support, among the Society of Critical Care Medicine Thrive Peer
Support Collaborative. We also sought to categorize key distinctions between these models
and elucidate barriers and facilitators to implementation.
Subjects: 17 Thrive sites from the USA, UK, and Australia were represented by a range of
healthcare professionals.
Interventions: Via an iterative process of in-person and email/conference calls, members
of the Collaborative, defined the key areas on which peer support models could be defined
and compared; collected detailed self-reports from all sites; reviewed the information and
identified clusters of models. Barriers and challenges to implementation of peer support
models were also documented.
Results: Within the Thrive Collaborative, six general models of peer support were identified:
Community based, Psychologist-led outpatient, Models based within ICU follow-up clinics,
Online, Groups based within ICU and Peer mentor models. The most common barriers to
implementation were: recruitment to groups, personnel input and training: sustainability
and funding, risk management and measuring success.
Conclusion: A number of different models of peer support are currently being developed
to help patients and families recover and grow in the post-critical care setting
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