Data analysis strategies for the detection of gravitational waves in non-Gaussian noise

In order to analyze data produced by the kilometer-scale gravitational wave detectors that will begin operation early next century, one needs to develop robust statistical tools capable of extracting weak signals from the detector noise. This noise will likely have non-stationary and non-Gaussian components. To facilitate the construction of robust detection techniques, I present a simple two-component noise model that consists of a background of Gaussian noise as well as stochastic noise bursts. The optimal detection statistic obtained for such a noise model incorporates a natural veto which suppresses spurious events that would be caused by the noise bursts. When two detectors are present, I show that the optimal statistic for the non-Gaussian noise model can be approximated by a simple coincidence detection strategy. For simulated detector noise containing noise bursts, I compare the operating characteristics of (i) a locally optimal detection statistic (which has nearly-optimal behavior for small signal amplitudes) for the non-Gaussian noise model, (ii) a standard coincidence-style detection strategy, and (iii) the optimal statistic for Gaussian noise.Comment: 5 pages RevTeX, 4 figure

Five Steps to a Better U: Improving the Crime-fighting Visa

Congress created the U nonimmigrant status to assist noncitizen vic- tims of serious crime and to encourage them to assist law enforce- ment in the investigation of that crime. Despite these laudable goals, the process has been flawed since the outset. U visas were capped at 10,000 per year, eventually precipitating a multi-year backlog that diminishes the incentive to report crime for persons who fear depor- tation. Of particular importance, the willingness of law enforcement officers to provide a certification of helpfulness—a mandatory com- ponent of an application for U status—varies tremendously across agencies. Eligibility for U status is thus a matter of “geographic rou- lette.” New policies implemented under the Trump Administration threaten this already fraught scheme. In particular, the Department of Homeland Security has reinvigorated cooperative enforcement agreements with state and local police and expanded removal priori- ties to include those merely charged or suspected of criminal activity. These developments mean that undocumented victims of serious crime expose themselves to significant risk of deportation when they involve the police. When crime is unreported, perpetrators may re- main at large, free to offend again. Particularly in domestic violence situations, survivors and their families remain vulnerable to further harm. Ironically, these results conflict with another stated initiative of the Trump Administration: fighting crime. This symposium essay offers five concrete reforms that would ameliorate the problems hampering the effectiveness of the U visa

Hyperinsulinemic hypoglycemia in children and adolescents: Recent advances in understanding of pathophysiology and management

Hyperinsulinemic hypoglycemia (HH) is characterized by unregulated insulin release, leading to persistently low blood glucose concentrations with lack of alternative fuels, which increases the risk of neurological damage in these patients. It is the most common cause of persistent and recurrent hypoglycemia in the neonatal period. HH may be primary, Congenital HH (CHH), when it is associated with variants in a number of genes implicated in pancreatic development and function. Alterations in fifteen genes have been recognized to date, being some of the most recently identified mutations in genes HK1, PGM1, PMM2, CACNA1D, FOXA2 and EIF2S3. Alternatively, HH can be secondary when associated with syndromes, intra-uterine growth restriction, maternal diabetes, birth asphyxia, following gastrointestinal surgery, amongst other causes. CHH can be histologically characterized into three groups: diffuse, focal or atypical. Diffuse and focal forms can be determined by scanning using fluorine-18 dihydroxyphenylalanine-positron emission tomography. Newer and improved isotopes are currently in development to provide increased diagnostic accuracy in identifying lesions and performing successful surgical resection with the ultimate aim of curing the condition. Rapid diagnostics and innovative methods of management, including a wider range of treatment options, have resulted in a reduction in co-morbidities associated with HH with improved quality of life and long-term outcomes. Potential future developments in the management of this condition as well as pathways to transition of the care of these highly vulnerable children into adulthood will also be discussed.This article is freely available via Open Access. Click on the Publisher URL to access it via the publisher's site.Nick Oliver is supported by the NIHR BRC at Imperial College Healthcare NHS Trust. The views expressed are those of the authors and not necessarily those of the NHS, the NIHR or the Department of Health. The other authors have no funding to declare. Sarah Flanagan is supported by a Sir Henry Dale Fellowship jointly funded by the Wellcome Trust and the Royal Society (105,636/Z/14/Z). The other authors are not supported by grants or fellowships.published version, accepted version (12 month embargo

Radion Potential and Brane Dynamics

We examine the cosmology of the Randall-Sundrum model in a dynamic setting where scalar fields are present in the bulk as well as the branes. This generates a mechanism similar to that of Goldberger-Wise for radion stabilization and the recovery of late-cosmology features in the branes. Due to the induced radion dynamics, the inflating branes roll towards the minimum of the radion potential, thereby exiting inflation and reheating the Universe. In the slow roll part of the potential, the 'TeV' branes have maximum inflation rate and energy as their coupling to the radion and bulk modes have minimum suppresion. Hence, when rolling down the steep end of the potential towards the stable point, the radion field (which appears as the inflaton of the effective 4D theory in the branes) decays very fast, reheats the Universe .This process results decayin a decrease of brane's canonical vacuum energy $\Lambda_4$. However, at the minimum of the potential $\Lambda_4$ is small but not neccessarily zero and the fine-tuning issue remains .Density perturbation constraints introduce an upper bound when the radion stabilizies. Due to the large radion mass and strong suppression to the bulk modes, moduli problems and bulk reheating do not occur. The reheat temperature and a sufficient number of e-folding constraints for the brane-universe are also satisfied. The model therefore recovers the radiation dominated FRW universe.Comment: 16 pages, 3 figures,extraneous sentences removed, 2 footnotes added, some typos correcte

Constraining neutron star tidal Love numbers with gravitational wave detectors

Ground-based gravitational wave detectors may be able to constrain the nuclear equation of state using the early, low frequency portion of the signal of detected neutron star - neutron star inspirals. In this early adiabatic regime, the influence of a neutron star's internal structure on the phase of the waveform depends only on a single parameter lambda of the star related to its tidal Love number, namely the ratio of the induced quadrupole moment to the perturbing tidal gravitational field. We analyze the information obtainable from gravitational wave frequencies smaller than a cutoff frequency of 400 Hz, where corrections to the internal-structure signal are less than 10 percent. For an inspiral of two non-spinning 1.4 solar mass neutron stars at a distance of 50 Mpc, LIGO II detectors will be able to constrain lambda to lambda < 2.0 10^{37} g cm^2 s^2 with 90% confidence. Fully relativistic stellar models show that the corresponding constraint on radius R for 1.4 solar mass neutron stars would be R < 13.6 km (15.3 km) for a n=0.5 (n=1.0) polytrope.Comment: 4 pages, 2 figures, minor correction

Optimising the use of Materials for Construction MSMEs: Building a Comprehensive Framework for Decision-Making and Resource Allocation through an Analytic Hierarchy Process

The efficiency, governance, and compliance with environmental ideals in construction is made possible thanks to a decision support system that ensures Materials, Models, and Methods (3Ms) are adaptable and integrated. Recent advances in Information Technology (IT), for instance, facilitate the visualisation of sequences and production stages in construction. Yet, this falls short in giving compatibility among the 3Ms, their suitability and workability, and their financial and legislative viability. To this end, this manuscript rethinks the concept of productivity, and lays the foundation for a new decision support system that is simple, affordable, and portable enough to attract large enterprises and MSMEs. Ideally, an efficient construction project has good flow of workstreams, is least complex, cost minimised but with added value, timely and in symbiosis with natural health provisions of the ecosystem. A mixed methodology based on gathering data from document reviews, semi-structured interviews, and observations of selected construction MSMEs, will allow to carry out longitudinal research and then code, group, link and analyse the collected raw data through the Analytic Hierarchy Process (AHP) Multi Criteria Decision Making technique. This technique is chosen to develop overall priorities for ranking the alternatives, measure, and monetise the impacting factors to draw out the main impediments to achieve good levels of efficiency. The outputs of the AHP analysis feeds into the novel decision support system, the concepts of which are introduced in this contribution

Understanding the complexity of materials procurement in construction projects to build a conceptual framework influencing supply chain management of MSMEs

Purchasing is a fundamental step of materials procurement in the construction sector, and since materials can represent up to 70% of the project's construction costs, reducing wastage and improving productivity can have big benefits, both for the environment and the economy, especially for Micro, Small, and Medium-sized Enterprises (MSMEs). This manuscript will focus on the process of purchasing materials from these companies’ perspective, seeking to investigate the impact of effective materials management on site. In light of the acknowledged absence of system thinking for MSMEs, this research aims to build a new conceptual framework that illustrates the complexity of the materials purchasing process in construction and embodies the risks linked to materials, relationships, information, and cash flows. The conceptual framework aims to influence supply management in construction and is based on the recognition of five main levels, going from the specification of materials to data management and feedback. It is designed to illustrate the sequence, logical structure, and complexities of the purchasing process. Data from the literature, followed by on-site observations, feeds into the framework

Ionization Structure and the Reverse Shock in E0102-72

The young oxygen-rich supernova remnant E0102-72 in the Small Magellanic Cloud has been observed with the High Energy Transmission Grating Spectrometer of Chandra. The high resolution X-ray spectrum reveals images of the remnant in the light of individual emission lines of oxygen, neon, magnesium and silicon. The peak emission region for hydrogen-like ions lies at larger radial distance from the SNR center than the corresponding helium-like ions, suggesting passage of the ejecta through the "reverse shock". We examine models which test this interpretation, and we discuss the implications.Comment: 4 pages, 6 figures; To appear in "Young Supernova Remnants" (11th Annual Astrophysics Conference in Maryland), S. S. Holt & U. Hwang (eds), AIP, New York (2001