93,287 research outputs found
Observation of cooper pair splitting and andreev bound states in carbon nanotubes
No full textIn this thesis, we investigate Cooper pair splitting in double quantum dot devices made from carbon nanotubes. We present transport measurements in which the controlled splitting of Cooper pairs dominates the current through such a device, reaching unprecedented splitting efficiencies of up to 90%.
In another experiment we use Cooper pair splitting (and a related non-local transport processes) as a tool to investigate Andreev bound states. Andreev bound states are a key concept in mesoscopic superconductivity. They can form due to the penetration of Cooper pairs into a quantum dot, leading to a new type of energy level that differs drastically from conventional particle-in-a-box states
Object orientation without extending Z
No full textThe good news of this paper is that without extending Z,
we can elegantly specify object-oriented systems, including encapsulation,
inheritance and subtype polymorphism (dynamic dispatch). The
bad news is that this specification style is rather different to normal
Z specifications, more abstract and axiomatic, which means that it is
not so well supported by current Z tools such as animators. It also enforces
behavioural subtyping, unlike most object-oriented programming
languages. This paper explains the proposed style, with examples, and
discusses its advantages and disadvantages
Joel Cooper Discusses Lung Volume Reduction Surgery
No full textIn this interview, Joel Dunning of the James Cook University Hospital in Middlesbrough, UK, discusses lung volume reduction surgery (LVRS) with Joel Cooper of the Hospital of the University of Pennsylvania in Philadelphia, USA. LVRS is a technique that Dr Cooper pioneered and with which he has achieved consistently good results. Dr Cooper discusses indications for the procedure, his views on the NETT trial (1), and the critical role that postoperative care plays in ensuring good outcomes after LVRS.ReferencesNaunheim KS, Wood DE, Mohsenifar Z, et al; National Emphysema Treatment Trial Research Group. Long-term follow-up of patients receiving lung-volume-reduction surgery versus medical therapy for severe emphysema by the National Emphysema Treatment Trial Research Group. Ann Thorac Surg. 2006;82(2):431-443.</div
Relationship between changes in bone mineral density and fracture risk reduction with antiresorptive drugs: some issues with meta-analyses
No full textIntroduction: the role of the increase in bone mineral density (BMD) in fracture risk reduction observed in osteoporotic patients treated with antiresorptive drugs is unclear. We examined the effects of study selection, the use of summary statistics or individual patient data (IPD) as the basis for the analyses, and the choice of BMD values used on the outcome of meta-analyses.Materials and Methods: to evaluate the effects of study selection, we performed Poisson regression analyses using the results from a number of published studies. To evaluate the effects of using individual patient data instead of summary statistics, we simulated the IPD for vertebral fracture to match the summary statistics for published trials and compared these results with those based on meta-regression using summary statistics. We also evaluated the effect of varying the BMD increase with treatment (3-8%) used in predicting the fracture risk reductions in these simulations.Results: the Poisson regression, which found a statistically significant relationship between nonvertebral fracture risk and spinal BMD when 18 trials of varying designs, duration, and sample size were included in the analysis (p = 0.02), was no longer significant when the analysis was based on the 7 large studies that were placebo-controlled, at least 3 years in duration (at least 1000 patient-years). Meta-analyses of simulated IPD from 12 trials of six antiresorptive agents gave accurate results regardless of the proportion of vertebral risk reduction assumed to be related to BMD change, whereas meta-regression based on summary statistics always produced an estimate around 50%. When the actual data from two risedronate studies were analyzed, the meta-regression based on summary statistics demonstrated a stronger correlation between BMD change and fracture risk reduction than the results based on the IPD analysis. In predicting the fracture risk reduction, the use of the average BMD gain (3%) observed in all studies in the calculations produced an overall fracture risk reduction very similar to the one observed clinically. In contrast, the use of a large BMD gain (8%) produced a substantially higher estimated fracture risk reduction and resulted in a high proportion of fracture risk reduction being attributed to BMD change.Conclusions: many factors may influence the outcome of meta-analyses, and caution should be used in interpreting the results of such analyses when exploring the relationship between BMD changes and fracture risk reduction with antiresorptive therapy of osteoporosis
M. Postel et Z. Cooper, Bastar Folk Art. Shrines, Figurines and Memorials (Publications VIII)
No full textVergati Anne. M. Postel et Z. Cooper, Bastar Folk Art. Shrines, Figurines and Memorials (Publications VIII). In: Arts asiatiques, tome 55, 2000. p. 181
M. Postel et Z. Cooper, Bastar Folk Art. Shrines, Figurines and Memorials (Publications VIII)
No full textVergati Anne. M. Postel et Z. Cooper, Bastar Folk Art. Shrines, Figurines and Memorials (Publications VIII). In: Arts asiatiques, tome 55, 2000. p. 181
The Benefits of Being Economics Professor A (and not Z)
No full textAlphabetic name ordering on multi-authored academic papers, which is the convention in the economics discipline and various other disciplines, is to the advantage of people whose last name initials are placed early in the alphabet. As it turns out, Professor A, who has been a first author more often than Professor Z, will have published more articles and experienced afaster growth rate over the course of her career as a result of reputation and visibility. Moreover, authors know that name ordering matters and indeed take ordering seriously: Several characteristics of an author group composition determine the decision to deviate from the default alphabetic name order to a significant extent.performance measurement, incentives, economists, name ordering
Tunneling of Cooper pairs across voltage-biased asymmetric single-Cooper-pair transistors
No full textWe analyze tunneling of Cooper pairs across voltage biased asymmetric single-Cooper-pair transistors. Also tunneling of Cooper pairs across two capacitively coupled Cooper-pair boxes is considered, when the capacitive coupling and Cooper pair tunneling are provided by a small Josephson junction between the islands. The theoretical analysis is done at subgap voltages, where the current-voltage characteristics depend strongly on the macroscopic eigenstates of the island(s) and their coupling to the dissipative environment. As the environment we use an impedance which satisfies Re[Z(ω)]⪡RQ and a few LC oscillators in series with Z(ω). The numerically calculated I−V curves are compared with experiments where the quantum states of mesoscopic SQUIDs are probed with inelastic Cooper pair tunneling. The main features of the observed I−V data are reproduced. Especially, we find traces of band structure in the higher excited states of the Cooper-pair boxes as well as traces of multiphoton processes between two Cooper-pair boxes in the regime of large Josephson coupling EJ⪢EC.Peer reviewe
Final word on Jersey Dutch
No full textIn this article, William Z. Shetter compares and contrasts the dialects that developed between different Dutch colonies in the New World. He explores in-depth the nuances of Jersey Dutch, and provides theories to explain how Dutch and colonial languages blended. The article is reprinted from American Speech, December 1958, Volum XXXIII, No. 4
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