1,128 research outputs found
Distinguishing personal use of drugs from drug supply: Approaches and challenges
The ability to fairly and justly distinguish between drug possession for personal use and drug possession for supply is a central feature of drug laws across the globe. Whether such distinctions pertain to decriminalisation of simple possession, or to the penalties associated with drug offences, such differentiation remains a core problem for policymakers. In this commentary, taking 91 different jurisdictions into consideration, we identify five different approaches to distinguishing personal use from supply: four of these involved quantification of an amount of drug (whether in weight or number of doses). The other approach relied on case-by-case judgement. Drawing upon survey data of drug use from nine countries, we provide an example of how the quantity bears little resemblance to drug use patterns, and does not take heterogeneity of drug use into account. While the non-quantified approach can lead to discriminatory and racialised policing, all of the quantification approaches also pose problems, largely concerned with arbitrary amounts. There appears to be no perfect way to differentiate possession for personal use from intentions to supply. This commentary opens up a number of important policy-relevant research questions given this central feature of drug policy design
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Centrifuge modelling of tunneling-induced settlement damage to 3D-printed surface structures
For urban tunneling projects it is essential to predict and prevent building damage. Although various case studies and experiments have shown that buildings considerably modify greenfield soil movements, widely accepted damage assessment methods neglect this soil-structure interaction and simplify structures as linear elastic beams. This paper summarizes an experimental investigation of the response of more realistic structures to tunneling-induced deformations. Small scale structural models with facade openings and brittle material properties were 3D printed and tested in a geotechnical centrifuge. Soil and structure displacement data were obtained by image-based measurement. Results demonstrate that structures notably mitigate differential greenfield ground displacements. It is also shown that maximum soil settlements, horizontal soil displacements beneath the structure and structural damage in the form of cracking significantly depend on the position of the structure in the settlement profile. The results provide a basis from which to predict building settlement response with greater certainty
Influence of building characteristics on tunnelling-induced ground movements
The interaction mechanisms between surface structures and tunnelling-induced ground movements were investigated through centrifuge testing. Although numerous studies have considered this soil–structure interaction problem, previous experiments have neglected important building characteristics and field data inherently contain numerous uncertainties related to the soil, the structure and the tunnelling procedure. Consequently, the interpretation of results and validation of computational models can be problematic. In this study, tunnelling beneath three-dimensional printed structural models with varying building characteristics (i.e. position, length and facade openings) was simulated in a centrifuge. The experimental results demonstrate that tunnelling induces soil displacements at the surface and subsurface that are notably altered due to nearby structures. Specifically, different amounts of vertical and horizontal ground movements, soil dilation and widening of settlement troughs were observed. Building distortions and horizontal building strains were also affected by the relative position of the building to the tunnel, the building length and the area of facade openings. The experimental results provide important data for the evaluation of current design methods and verification of computational models.The authors thank the Engineering and Physical Sciences Research Council (grant EP/KP018221/1) and Crossrail for financially supporting this research
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Centrifuge modelling of building response to tunnel excavation
Understanding the building response to tunnelling-induced settlements is an important aspect of urban tunnelling in soft ground. Previous centrifuge modelling research demonstrated significant potential to study this tunnel–soil–structure interaction problem. However, these recent studies were limited by simplified building models, which might result in uncertainties when interpreting the building performance to tunnelling subsidence. This paper presents an experimental modelling procedure and the results of a series of centrifuge tests, involving relatively complex surface structures subjected to tunnelling in sand. Powder-based three-dimensional (3D) printing was adopted to fabricate building models with realistic layouts, facade openings and foundations. The 3D printed material had a Young's modulus and a brittle response similar to historic masonry. Modelling effects and boundary conditions are quantified. The good agreement between the experimentally obtained results and previous research demonstrates that the soil–structure interaction during tunnel excavation is well replicated. The experimental procedure provides a framework to quantify how building features affect the response of buildings to tunnelling subsidence.The authors are grateful to EPSRC grant EP/K018221/1 and Crossrail for the financial support
Fat embolism syndrome: improved diagnosis through the use of bedside echocardiography
No abstract available. Article truncated at 150 words. A 77 year old female with a past medical history of dementia, chronic atrial fibrillation requiring anticoagulation, hypertension, biventricular congestive heart failure with a preserved left ventricular ejection fraction, pulmonary hypertension, and chronic obstructive pulmonary disease (COPD) presented to the emergency room after she sustained a ground level fall while sitting in a chair. The patient reportedly fell asleep while sitting at the kitchen table, and subsequently fell to her right side. According to witnesses, she did not strike her head, and there was no observed loss of consciousness. As part of her initial evaluation, at an outside hospital, radiographs of the pelvis, hip, and knee were obtained. These identified a definitive right superior pubic ramus fracture with inferior displacement and a questionable fracture of the right femoral neck. Shortly thereafter, the patient was transferred to our hospital for further management. On exam, the patient had a painful right hip
A survey of location inference techniques on Twitter
The increasing popularity of the social networking service, Twitter, has made it more involved in day-to-day communications, strengthening social relationships and information dissemination. Conversations on Twitter are now being explored as indicators within early warning systems to alert of imminent natural disasters such as earthquakes and aid prompt emergency responses to crime. Producers are privileged to have limitless access to market perception from consumer comments on social media and microblogs. Targeted advertising can be made more effective based on user profile information such as demography, interests and location. While these applications have proven beneficial, the ability to effectively infer the location of Twitter users has even more immense value. However, accurately identifying where a message originated from or an author’s location remains a challenge, thus essentially driving research in that regard. In this paper, we survey a range of techniques applied to infer the location of Twitter users from inception to state of the art. We find significant improvements over time in the granularity levels and better accuracy with results driven by refinements to algorithms and inclusion of more spatial features
The Leeds Evaluation of Efficacy of Detoxification Study (LEEDS) project: An open-label pragmatic randomised control trial comparing the efficacy of differing therapeutic agents for primary care detoxification from either street heroin or methadone [ISRCTN07752728]
BACKGROUND:
Heroin is a synthetic opioid with an extensive illicit market leading to large numbers of people becoming addicted. Heroin users often present to community treatment services requesting detoxification and in the UK various agents are used to control symptoms of withdrawal. Dissatisfaction with methadone detoxification [8] has lead to the use of clonidine, lofexidine, buprenorphine and dihydrocodeine; however, there remains limited evaluative research. In Leeds, a city of 700,000 people in the North of England, dihydrocodeine is the detoxification agent of choice. Sublingual buprenorphine, however, is being introduced. The comparative value of these two drugs for helping people successfully and comfortably withdraw from heroin has never been compared in a randomised trial. Additionally, there is a paucity of research evaluating interventions among drug users in the primary care setting. This study seeks to address this by randomising drug users presenting in primary care to receive either dihydrocodeine or buprenorphine.
METHODS/DESIGN:
The Leeds Evaluation of Efficacy of Detoxification Study (LEEDS) project is a pragmatic randomised trial which will compare the open use of buprenorphine with dihydrocodeine for illicit opiate detoxification, in the UK primary care setting. The LEEDS project will involve consenting adults and will be run in specialist general practice surgeries throughout Leeds. The primary outcome will be the results of a urine opiate screening at the end of the detoxification regimen. Adverse effects and limited data to three and six months will be acquired
An Elementary Quantum Network of Single Atoms in Optical Cavities
Quantum networks are distributed quantum many-body systems with tailored
topology and controlled information exchange. They are the backbone of
distributed quantum computing architectures and quantum communication. Here we
present a prototype of such a quantum network based on single atoms embedded in
optical cavities. We show that atom-cavity systems form universal nodes capable
of sending, receiving, storing and releasing photonic quantum information.
Quantum connectivity between nodes is achieved in the conceptually most
fundamental way: by the coherent exchange of a single photon. We demonstrate
the faithful transfer of an atomic quantum state and the creation of
entanglement between two identical nodes in independent laboratories. The
created nonlocal state is manipulated by local qubit rotation. This efficient
cavity-based approach to quantum networking is particularly promising as it
offers a clear perspective for scalability, thus paving the way towards
large-scale quantum networks and their applications.Comment: 8 pages, 5 figure
ERP evidence suggests executive dysfunction in ecstasy polydrug users
Background: Deficits in executive functions such as access to semantic/long-term memory have been shown in ecstasy users in previous research. Equally, there have been many reports of equivocal findings in this area. The current study sought to further investigate behavioural and electro-physiological measures of this executive function in ecstasy users.
Method: Twenty ecstasy–polydrug users, 20 non-ecstasy–polydrug users and 20 drug-naïve controls were recruited. Participants completed background questionnaires about their drug use, sleep quality, fluid intelligence and mood state. Each individual also completed a semantic retrieval task whilst 64 channel Electroencephalography (EEG) measures were recorded.
Results: Analysis of Variance (ANOVA) revealed no between-group differences in behavioural performance on the task. Mixed ANOVA on event-related potential (ERP) components P2, N2 and P3 revealed significant between-group differences in the N2 component. Subsequent exploratory univariate ANOVAs on the N2 component revealed marginally significant between-group differences, generally showing greater negativity at occipito-parietal electrodes in ecstasy users compared to drug-naïve controls. Despite absence of behavioural differences, differences in N2 magnitude are evidence of abnormal executive functioning in ecstasy–polydrug users
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