9,316 research outputs found
A Dichotomy Theorem for the Approximate Counting of Complex-Weighted Bounded-Degree Boolean CSPs
We determine the computational complexity of approximately counting the total
weight of variable assignments for every complex-weighted Boolean constraint
satisfaction problem (or CSP) with any number of additional unary (i.e., arity
1) constraints, particularly, when degrees of input instances are bounded from
above by a fixed constant. All degree-1 counting CSPs are obviously solvable in
polynomial time. When the instance's degree is more than two, we present a
dichotomy theorem that classifies all counting CSPs admitting free unary
constraints into exactly two categories. This classification theorem extends,
to complex-weighted problems, an earlier result on the approximation complexity
of unweighted counting Boolean CSPs of bounded degree. The framework of the
proof of our theorem is based on a theory of signature developed from Valiant's
holographic algorithms that can efficiently solve seemingly intractable
counting CSPs. Despite the use of arbitrary complex weight, our proof of the
classification theorem is rather elementary and intuitive due to an extensive
use of a novel notion of limited T-constructibility. For the remaining degree-2
problems, in contrast, they are as hard to approximate as Holant problems,
which are a generalization of counting CSPs.Comment: A4, 10pt, 20 pages. This revised version improves its preliminary
version published under a slightly different title in the Proceedings of the
4th International Conference on Combinatorial Optimization and Applications
(COCOA 2010), Lecture Notes in Computer Science, Springer, Vol.6508 (Part I),
pp.285--299, Kailua-Kona, Hawaii, USA, December 18--20, 201
Fit to practise? Processes for dealing with misconduct among pharmacists in Australia, Canada, the UK and US
© 2018 Elsevier Inc.In many countries with legal systems based on English common law, pharmacy regulators have a responsibility to protect, promote and maintain the health and safety of patients. Where there is a potential risk to patient safety, or where the public's confidence in pharmacy could be adversely affected by the actions of a pharmacist, these regulators have a statutory duty to investigate concerns. The legal provisions underpinning each jurisdiction's disciplinary processes depict distinctive outlooks from the different authorities, as each works towards the same goal. Legal statues, regulations, rules, and guidance affecting the disciplinary process in Great Britain, Australia, New York and New Brunswick were collated, and the processes they describe were attached to a common process flow diagram for step-by-step evaluation of their respective legal provisions. The initial stages of the respective investigation process are broadly similar in all the jurisdictions examined; however, each process has subtle differences that afford some level of advantage or disadvantage over its comparators. Factors including: how matters of discipline are framed; the existence of a separate process for minor and uncontested violations; the ability to effect an interim suspension of a practitioner's license; threshold criteria for escalation of complaints; the membership of disciplinary panels; and the perceived independence of these panels all philosophically affect the public safety remit of each regulator. This work constitutes the first comparison of international regulatory frameworks for the profession of pharmacy. Of the four jurisdictions examined, Great Britain most clearly acts in the interest of the public and the profession – rather than the respondent pharmacist – at every step of its process.Peer reviewe
Investigation to optimize the passive shock wave/boundary layer control for supercritical airfoil drag reduction
The passive shock wave/boundary layer control for reducing the drag of 14%-thick supercritical airfoil was investigated in the 3 in. x 15.4 in. RPI Transonic Wind Tunnel with and without the top wall insert at transonic Mach numbers. Top wall insert was installed to increase the flow Mach number to 0.90 with the model mounted on the test section bottom wall. Various porous surfaces with a cavity underneath were positioned on the area of the airfoil where the shock wave occurs. The higher pressure behind the shock wave circulates flow through the cavity to the lower pressure ahead of the shock wave. The effects from this circulation prevent boundary layer separation and enthropy increase hrough the shock wave. The static pressure distributions over the airfoil, the wake impact pressure survey for determining the profile drag and the Schlieren photographs for porous surfaces are presented and compared with the results for solid surface airfoil. With a 2.8% uniform porosity the normal shock wave for the solid surface was changed to a lambda shock wave, and the wake impact pressure data indicate a drag coefficient reduction as much as 45% lower than for the solid surface airfoil at high transonic Mach numbers
AMTRAN development program Interim report
AMTRAN software system developed for IBM 1130 compute
The influence of grazing on land surface climatological variables
Research accomplishments in empirical measurements, laboratory analyses, data analyses, and modeling are summarized. Publications are listed. Presentations made during the funding period are also listed
The Presentation of Selfie in Everyday Life:Considering the Relationship Between Social Media Design and User in the Online Actions and Interactions of Young People
Against a backdrop of young people increasingly using an array of social media platforms for a range of social activities [20], accessed through a variety of devices [27], this paper reports upon the findings of a research project considering the effect of these platforms upon the actions and interactions of young people. Reporting on findings from a series of interviews conducted over the course of a year with nine participants, the research discusses the participants' thoughts and impressions of the platforms, their uses of specific features, their social actions and interactions, and the effects of changes in their offline lives and their specific socio- cultural situations upon their online interactions. The findings reveal a range of social media engagements by young people across a wide array of platforms, with the participants' specific concerns and needs shaping how they engaged with social media. It was also found that the platforms played a role in shaping the actions and interactions of the young people, limiting what was possible for them and informing how they approached social interaction on each platform. As such, it was noted that online social interactions are increasingly nuanced and multi-faceted, and therefore an approach towards analyzing interactions online needs to account for the interplay between design and user from which unique and ongoing interactions emerge
The influence of grazing on surface climatological variables of tallgrass prairie
Mass and energy exchange between most grassland canopies and the atmosphere are mediated by grazing activities. Ambient temperatures can be increased or decreased by grazers. Data have been assembled from simulated grazing experiments on Konza Prairie Research Natural Area and observations on adjacent pastures grazed by cattle show significant changes in primary production, nutrient content, and bidirectional reflectance characteristics as a function of grazing intensity. The purpose of this research was to provide algorithms that would allow incorporation of grazing effects into models of energy budgets using remote sensing procedures. The approach involved: (1) linking empirical measurements of plant biomass and grazing intensities to remotely sensed canopy reflectance, and (2) using a higher resolution, mechanistic grazing model to derive plant ecophysiological parameters that influence reflectance and other surface climatological variables
Wavelet Monte Carlo dynamics
The Wavelet Monte Carlo dynamics (WMCD) algorithm is developed from scratch to simulate hydrodynamically coupled Brownian particles at low Reynolds numbers. The basic premise is to construct a regularised version of the Oseen tensor out of a distribution of 3-dimensional vector wavelets that displace groups of particles so as to evolve the system in time while correlating the motion of all particles according to their separation. In doing so, the Oseen tensor is made implicit in the simulation code and the computational complexity of WMCD scales with system size N as N lnN (or even linearly in fractal systems), comparing favourably to existing Brownian dynamics algorithms, while the absence of any solvent degrees of freedom also leads to favourable comparisons with explicit-solvent methods. WMCD therefore holds promise to simulate system sizes beyond the reach of the alternatives. Key extensions to the basic algorithm are presented - none of which affect the computational complexity - including additional Fourier moves and smart Monte Carlo biasing to improve the algorithm's dynamical fidelity, as well as schemes to build in polydispersity and hydrodynamic coupling of particle rotations. WMCD is then used in a comprehensive study of the diffusion of isolated polymer chains, using the properties of the centre of mass velocity autocorrelation to identify distinct short and long-time regimes driving the reduction of diffusivity from the Kirkwood value. Using similar methods in a very different context, WMCD is also used to study the enhanced diffusion of passive particles in active suspensions. Here again the velocity autocorrelation proves useful in understanding the underlying physics, with three driving mechanisms identified depending on relative particle sizes. Of particular note is the importance of thermal fluctuations, often neglected in active matter research but central to WMCD
Understanding the social in a digital age
Datafication, algorithms, social media and their various assemblages enable massive connective processes, enriching personal interaction and amplifying the scope and scale of public networks. At the same time, surveillance capitalists and the social quantification sector are committed to monetizing every aspect of human communication, all of which threaten ideal social qualities, such as togetherness and connection. This Special Issue brings together a range of voices and provocations around ‘the social’, all of which aim to critically interrogate mediated human connection and their contingent socialities. Conventional methods may no longer be adequate, and we must rethink not only the fabric of the social but the very tools we use to make sense of our changing social formations. This Special Issue raises shared concerns with what the social means today, unpicking and rethinking the seams between digitization and social life that characterize today’s digital age
Fluorides, orthodontics and demineralization: a systematic review
Objectives: To evaluate the effectiveness of fluoride in preventing white spot lesion (WSL) demineralization during orthodontic treatment and compare all modes of fluoride delivery.
Data sources: The search strategy for the review was carried out according to the standard Cochrane systematic review methodology. The following databases were searched for RCTs or CCTs: Cochrane Clinical Trials Register, Cochrane Oral Health Group Specialized Trials Register, MEDLINE and EMBASE. Inclusion and exclusion criteria were applied when considering studies to be included. Authors of trials were contacted for further data.
Data selection: The primary outcome of the review was the presence or absence of WSL by patient at the end of treatment. Secondary outcomes included any quantitative assessment of enamel mineral loss or lesion depth.
Data extraction: Six reviewers independently, in duplicate, extracted data, including an assessment of the methodological quality of each trial.
Data synthesis: Fifteen trials provided data for this review, although none fulfilled all the methodological quality assessment criteria. One study found that a daily NaF mouthrinse reduced the severity of demineralization surrounding an orthodontic appliance (lesion depth difference –70.0 µm; 95% CI –118.2 to –21.8 µm). One study found that use of a glass ionomer cement (GIC) for bracket bonding reduced the prevalence of WSL (Peto OR 0.35; 95% CI 0.15–0.84) compared with a composite resin. None of the studies fulfilled all of the methodological quality assessment criteria.
Conclusions: There is some evidence that the use of a daily NaF mouthrinse or a GIC for bonding brackets might reduce the occurrence and severity of WSL during orthodontic treatment. More high quality, clinical research is required into the different modes of delivering fluoride to the orthodontic patient
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