90 research outputs found

    H.L.A. HART By Neil MacCormick

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    English legal positivism began with the clarity of Jeremy Bentham and John Austin, but their clarity sometimes was achieved by sacrificing conceptual subtlety. In 1961 H.L.A. Hart published The Concept of Law and renewed the positivist tradition with a subtlety that did not sacrifice clarity. It is appropriate, therefore,that Neil MacCormick\u27s study of Hart should begin the monograph series Jurists: Profiles in Legal Theory.\u27The conceptual separation between law and morals serves as the primary tenet of legal positivism. Although positive morality (the moral beliefs prevalent in a particular society) influences the development of law, the law-once formed-exists as a distinct social fact. The English founders of positivism were utilitarians and thus committed to reforming both positive law and positive morality in light of the principle of utility. But the question of what the law should be, even within the framework of a critical morality like utilitarianism, must be distinguished from the question of what the law is. Thus, law conceptually is distinct both from the positive morality out of which law grows and from the reflective, critical morality that partly determines one\u27s reasoned evaluation of law.Hart never departs from this crucial positivist view that a legal system constitutes a complex social fact that is distinct from the positive morality of the society and from an ideal of law informed by critical moral thought

    Vacuum local and global electromagnetic self-energies for a point-like and an extended field source

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    We consider the electric and magnetic energy densities (or equivalently field fluctuations) in the space around a point-like field source in its ground state, after having subtracted the spatially uniform zero-point energy terms, and discuss the problem of their singular behavior at the source's position. We show that the assumption of a point-like source leads, for a simple Hamiltonian model of the interaction of the source with the electromagnetic radiation field, to a divergence of the renormalized electric and magnetic energy density at the position of the source. We analyze in detail the mathematical structure of such singularity in terms of a delta function and its derivatives. We also show that an appropriate consideration of these singular terms solves an apparent inconsistency between the total field energy and the space integral of its density. Thus the finite field energy stored in these singular terms gives an important contribution to the self-energy of the source. We then consider the case of an extended source, smeared out over a finite volume and described by an appropriate form factor. We show that in this case all divergences in local quantities such as the electric and the magnetic energy density, as well as any inconsistency between global and space-integrated local self-energies, disappear.Comment: 8 pages. The final publication is available at link.springer.co

    Improving the professional knowledge base for education: Using knowledge management (KM) and Web 2.0 tools

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    Improving education systems is an elusive goal. Despite considerable investment, international studies such as the OECD Teaching and Learning International Survey (TALIS) project and the McKinsey Report How the world’s best performing schools come out on top indicate that improving teacher quality is more important than increased financial investment. Both reports challenge governments, academics and practitioners to adopt new ways of sharing and building knowledge. This paper makes the case for national education systems to adopt tried and tested knowledge management and web 2.0 tools used by other sectors and highlights the neglected potential of teacher educators as agents for improvement

    Vitamin D and the risk of dementia and Alzheimer disease

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    Objective: To determine whether low vitamin D concentrations are associated with an increased risk of incident all-cause dementia and Alzheimer disease. Methods: One thousand six hundred fifty-eight elderly ambulatory adults free from dementia, cardiovascular disease, and stroke who participated in the US population?based Cardiovascular Health Study between 1992?1993 and 1999 were included. Serum 25-hydroxyvitamin D (25(OH)D) concentrations were determined by liquid chromatography-tandem mass spectrometry from blood samples collected in 1992?1993. Incident all-cause dementia and Alzheimer disease status were assessed during follow-up using National Institute of Neurological and Communicative Disorders and Stroke/Alzheimer\u27s Disease and Related Disorders Association criteria. Results: During a mean follow-up of 5.6 years, 171 participants developed all-cause dementia, including 102 cases of Alzheimer disease. Using Cox proportional hazards models, the multivariate adjusted hazard ratios (95% confidence interval [CI]) for incident all-cause dementia in participants who were severely 25(OH)D deficient (\u3c25 nmol/L) and deficient (?25 to \u3c50 nmol/L) were 2.25 (95% CI: 1.23?4.13) and 1.53 (95% CI: 1.06?2.21) compared to participants with sufficient concentrations (?50 nmol/L). The multivariate adjusted hazard ratios for incident Alzheimer disease in participants who were severely 25(OH)D deficient and deficient compared to participants with sufficient concentrations were 2.22 (95% CI: 1.02?4.83) and 1.69 (95% CI: 1.06?2.69). In multivariate adjusted penalized smoothing spline plots, the risk of all-cause dementia and Alzheimer disease markedly increased below a threshold of 50 nmol/L. Conclusion: Our results confirm that vitamin D deficiency is associated with a substantially increased risk of all-cause dementia and Alzheimer disease. This adds to the ongoing debate about the role of vitamin D in nonskeletal conditions

    PLA Logistics and Sustainment: PLA Conference 2022

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    The US Army War College People’s Liberation Army Conference (PLA) Conference was held March 31 to April 2, 2022, at Carlisle Barracks, Pennsylvania. The conference focused on PLA logistics and sustainment. As the PLA continues to build and modernize its combat forces, it is important to examine if the capabilities meant to support combat operations are also being developed. Specific topics included: 1) China’s national-level logistics, including how China mobilizes national resources for the military and how it provides joint logistics support to the PLA Theater Commands; 2) the logistics capabilities of the different PLA services, especially the Army, Navy, and Air Forces; 3) PLA logistics in China’s remote regions, such as airpower projection in the Western Theater Command along the Indian border; and, 4) the PLA’s ability to sustain overseas operations at its base in Djibouti. Despite notable potential shortfalls and points of friction, the PLA has successfully sustained counterpiracy maritime operations for many years and conducted noncombatant evacuation operations well-distant from China. It is increasingly able to move forces across the vast distances of China and conduct large training exercises. Far more must be known about PLA sustainment and logistics before the hard questions about PLA operational reach and endurance can be answered.https://press.armywarcollege.edu/monographs/1954/thumbnail.jp

    Direct and scalable deposition of atomically thin low-noise MoS2 membranes on apertures

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    Published in final edited form as: ACS Nano. 2015 July 28; 9(7): 7352–7359. doi:10.1021/acsnano.5b02369.Molybdenum disulfide (MoS2) flakes can grow beyond the edge of an underlying substrate into a planar freestanding crystal. When the substrate edge is in the form of an aperture, reagent-limited nucleation followed by edge growth facilitate direct and selective growth of freestanding MoS2 membranes. We have found conditions under which MoS2 grows preferentially across micrometer-scale prefabricated solid-state apertures in silicon nitride membranes, resulting in sealed membranes that are one to a few atomic layers thick. We have investigated the structure and purity of our membranes by a combination of atomic-resolution transmission electron microscopy, elemental analysis, Raman spectroscopy, photoluminescence spectroscopy, and low-noise ion-current recordings through nanopores fabricated in such membranes. Finally, we demonstrate the utility of fabricated ultrathin nanopores in such membranes for single-stranded DNA translocation detection.R21 HG006873 - NHGRI NIH HHS; R21-HG006873 - NHGRI NIH HHSPublished versio

    A blinded evaluation of the efficacy and safety of glycopyrronium, a once-daily long-acting muscarinic antagonist, versus tiotropium, in patients with COPD: the GLOW5 study

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    Abstract Background Two once-daily long-acting muscarinic antagonists (LAMAs) are currently available for the treatment of chronic obstructive pulmonary disease (COPD) – tiotropium and glycopyrronium. Previous studies have compared glycopyrronium with open-label tiotropium. In the GLOW5 study, we compare glycopyrronium with blinded tiotropium. Methods In this blinded, double-dummy, parallel group, 12-week study, patients with moderate-to-severe COPD were randomized 1:1 to glycopyrronium 50 μg once daily or tiotropium 18 μg once daily. The primary objective was to demonstrate the non-inferiority of glycopyrronium versus blinded tiotropium with respect to trough forced expiratory volume in 1 second (FEV1) following 12 weeks of treatment (non-inferiority margin: –50 mL). Secondary objectives were to evaluate glycopyrronium versus tiotropium for other spirometric outcomes, breathlessness (Transition Dyspnea Index; TDI), health status (St George’s Respiratory Questionnaire; SGRQ), daily rescue medication use, COPD exacerbations and COPD symptoms over 12 weeks of treatment. Results 657 patients were randomized (glycopyrronium: 327; tiotropium: 330); 96% (630 patients) completed the study. Least squares mean trough FEV1 for both glycopyrronium and tiotropium was 1.405 L at Week 12, meeting the criterion for non-inferiority (mean treatment difference: 0 mL, 95% CI: –32, 31 mL). Glycopyrronium demonstrated rapid bronchodilation following first dose on Day 1, with significantly higher FEV1 at all time points from 0–4 h post-dose versus tiotropium (all p < 0.001). FEV1 area under the curve from 0–4 h (AUC0–4h) post-dose with glycopyrronium was significantly superior to tiotropium on Day 1 (p < 0.001) and was comparable to tiotropium at Week 12. Glycopyrronium demonstrated comparable improvements to tiotropium in TDI focal score, SGRQ total score, rescue medication use and the rate of COPD exacerbations (all p = not significant). Patients on glycopyrronium also had a significantly lower total COPD symptom score versus patients on tiotropium after 12 weeks (p = 0.035). Adverse events were reported by a similar percentage of patients receiving glycopyrronium (40.4%) and tiotropium (40.6%). Conclusion In patients with moderate-to-severe COPD, 12-week blinded treatment with once-daily glycopyrronium 50 μg or tiotropium 18 μg, provided similar efficacy and safety, with glycopyrronium having a faster onset of action on Day 1 versus tiotropium. Trial registration ClinicalTrial.gov, NCT0161332

    Topology by Design in Magnetic nano-Materials: Artificial Spin Ice

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    Artificial Spin Ices are two dimensional arrays of magnetic, interacting nano-structures whose geometry can be chosen at will, and whose elementary degrees of freedom can be characterized directly. They were introduced at first to study frustration in a controllable setting, to mimic the behavior of spin ice rare earth pyrochlores, but at more useful temperature and field ranges and with direct characterization, and to provide practical implementation to celebrated, exactly solvable models of statistical mechanics previously devised to gain an understanding of degenerate ensembles with residual entropy. With the evolution of nano--fabrication and of experimental protocols it is now possible to characterize the material in real-time, real-space, and to realize virtually any geometry, for direct control over the collective dynamics. This has recently opened a path toward the deliberate design of novel, exotic states, not found in natural materials, and often characterized by topological properties. Without any pretense of exhaustiveness, we will provide an introduction to the material, the early works, and then, by reporting on more recent results, we will proceed to describe the new direction, which includes the design of desired topological states and their implications to kinetics.Comment: 29 pages, 13 figures, 116 references, Book Chapte
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