25 research outputs found
Multiple universes, cosmic coincidences, and other dark matters
Even when completely and consistently formulated, a fundamental theory of
physics and cosmological boundary conditions may not give unambiguous and
unique predictions for the universe we observe; indeed inflation, string/M
theory, and quantum cosmology all arguably suggest that we can observe only one
member of an ensemble with diverse properties. How, then, can such theories be
tested? It has been variously asserted that in a future measurement we should
observe the a priori most probable set of predicted properties (the
``bottom-up'' approach), or the most probable set compatible with all current
observations (the ``top-down'' approach), or the most probable set consistent
with the existence of observers (the ``anthropic'' approach). These inhabit a
spectrum of levels of conditionalization and can lead to qualitatively
different predictions. For example, in a context in which the densities of
various species of dark matter vary among members of an ensemble of otherwise
similar regions, from the top-down or anthropic viewpoints -- but not the
bottom-up -- it would be natural for us to observe multiple types of dark
matter with similar contributions to the observed dark matter density. In the
anthropic approach it is also possible in principle to strengthen this argument
and the limit the number of likely dark matter sub-components. In both cases
the argument may be extendible to dark energy or primordial density
perturbations. This implies that the anthropic approach to cosmology,
introduced in part to explain "coincidences" between unrelated constituents of
our universe, predicts that more, as-yet-unobserved coincidences should come to
light.Comment: 18 JCAP-style pages, accepted by JCAP. Revised version adds
references and some clarification
Between the Post and the Com-Post:Examining the Postdigital ‘Work’ of a Prefix
In examining the work of the prefix ‘post’, we aim to contribute to the current postdigital dialogue. Our paper does not provide a rationale for the use of ‘postdigital’ in the title of this journal: that has been thoroughly explored elsewhere. We want instead to consider the work the prefix might do. We look at ‘post’, as it appears to ‘act’ in the terms of ‘postmodernism’ and ‘posthumanism’, suggesting that modernism and humanism are in need of questioning and reworking. We also examine what gets ‘post-ed’, or sometimes ‘com-posted’. (Com- is another interesting prefix, meaning ‘with’.) We then consider how these inquiries inform our understanding of a ‘postdigital reality’ that humans now inhabit. We understand this as a space of learning, struggle, and hope, where ‘old’ and ‘new’ media are now ‘cohabiting artefacts’ that enmesh with the economy, politics and culture. In entering this postdigital age, there really is no turning back from a convergence of the traditional and the digital. However, this is not simply a debate about technological and non-technological media. The postdigital throws up new challenges and possibilities across all aspects of social life. We believe this opens up new avenues too, for considering ways that discourse (language-in-use) shapes how we experience the postdigital
Increasing response to a postal survey of sedentary patients – a randomised controlled trial [ISRCTN45665423]
BACKGROUND: A systematic review identified a range of methods, which can influence response rates. However, analysis specific to a healthcare setting, and in particular, involving people expected to be poor responders, was missing, We examined the effect of pre-warning letters on response rates to a postal survey of sedentary patients whom we expected a low rate of response. METHODS: Participants were randomised to receive a pre-warning letter or no pre-warning letter, seven days before sending the main questionnaire. The main questionnaire included a covering letter and pre-paid return envelope. After seven days, non-responders were sent a reminder letter and seven days later, another reminder letter with a further copy of the questionnaire and return envelope. RESULTS: 627 adults, with a mean age of 48 years (SD 13, range 18 to 78) of whom 69.2% (434/627) were women, were randomised. 49.0% (307/627) of patients were allocated to receive a pre-warning letter and 51.0% (320/627) no pre-warning letter, seven days in advance of posting the main questionnaire. The final response rate to the main questionnaire was 30.0% (92/307) amongst those sent a pre-warning letter and 20.9% (67/320) not sent a pre-warning letter, with an adjusted odds ratio of 1.60 (95% CI 1.1, 2.30). CONCLUSIONS: The relatively low cost method of sending a pre-warning letter had a modest impact on increasing response rates to a postal questionnaire sent to a group of patients for whom a low response rate was anticipated. Investigators should consider incorporating this simple intervention when conducting postal surveys, to reduce the potential for nonresponse bias and to increase the study power. Methods other than postal surveys may be needed however when a low response rate to postal surveys is likely
Research Horizons [Volume 20, Number 1, Fall 2002]
Quiet on the Hall -
Researchers search for ways to reduce noise and improve sleep in nursing homes.All for One, One for All -
Rehabilitation engineers' emphasis on helping people with disabilities will improve wireless technology for everyone.Shopping the Job Market -
Persistence and a positive mindset pay off in a job search.Making Unmanned Aerial Vehicles Smarter -
Recent test demonstrates in-flight ability to autonomously reconfigure low-level control system.Reversing Production -
Researchers develop system to recover and reuse electronic wastes.Q & A with Don Giddens -
Dean of the Georgia Tech College of Engineering.Risky Diseases, Risky Vaccines, Risky Policies
Public concern is rising about the risks of vaccination