2,991 research outputs found
Why Labor Unions Have Grown Reluctant To Use the “S” Word. Global, High-Tech Economy Makes Striking Riskier As Membership Declines. A Sense of Shared Purpose, 1999
Newspaper article about strikes and the role of unions in strikes, The Wall Street Journal. Vol. 104, No. 118, December 16, 1999
Using an Open Software System (Sakai) to Develop Student Portfolios
E-portfolios are digital collections of artifacts that represent the achievements and reflections of individuals. They offer a unique view into student learning and allow educators and external accreditors to assess student progress towards established standards as well as reviewing their program’s performance in supporting that progress. Students benefit from assembling their e-portfolios through the process of reviewing their own work with a critical eye, choosing pieces of their work that best represent their abilities, and reflecting on the transformative nature of their University experience, both in class and through extra-curricular, service learning, internships and international activities. An e-portfolio provides a holistic view of a student’s personal growth and abilities that will serve them well in their career search or graduate school application. The challenge for an institution is to provide this learning and assessment resource in an accessible and affordable vehicle that is manageable for both faculty and students. Roger Williams University has crafted a strategy to utilize the Sakai open source course management system with its integrated e-portfolio tool set and a linked website to provide both e-portfolios and program assessment. This strategy will also be employed to propose a virtual accreditation of a professional program that will serve as a model throughout the University and the broader higher education community
Demonstration of non-Markovian process characterisation and control on a quantum processor
In the scale-up of quantum computers, the framework underpinning
fault-tolerance generally relies on the strong assumption that environmental
noise affecting qubit logic is uncorrelated (Markovian). However, as physical
devices progress well into the complex multi-qubit regime, attention is turning
to understanding the appearance and mitigation of correlated -- or
non-Markovian -- noise, which poses a serious challenge to the progression of
quantum technology. This error type has previously remained elusive to
characterisation techniques. Here, we develop a framework for characterising
non-Markovian dynamics in quantum systems and experimentally test it on
multi-qubit superconducting quantum devices. Where noisy processes cannot be
accounted for using standard Markovian techniques, our reconstruction predicts
the behaviour of the devices with an infidelity of . Our results show
this characterisation technique leads to superior quantum control and extension
of coherence time by effective decoupling from the non-Markovian environment.
This framework, validated by our results, is applicable to any controlled
quantum device and offers a significant step towards optimal device operation
and noise reduction
Filtering crosstalk from bath non-Markovianity via spacetime classical shadows
From an open system perspective non-Markovian effects due to a nearby bath or
neighbouring qubits are dynamically equivalent. However, there is a conceptual
distinction to account for: neighbouring qubits may be controlled. We combine
recent advances in non-Markovian quantum process tomography with the framework
of classical shadows to characterise spatiotemporal quantum correlations.
Observables here constitute operations applied to the system, where the free
operation is the maximally depolarising channel. Using this as a causal break,
we systematically erase causal pathways to narrow down the progenitors of
temporal correlations. We show that one application of this is to filter out
the effects of crosstalk and probe only non-Markovianity from an inaccessible
bath. It also provides a lens on spatiotemporally spreading correlated noise
throughout a lattice from common environments. We demonstrate both examples on
synthetic data. Owing to the scaling of classical shadows, we can erase
arbitrarily many neighbouring qubits at no extra cost. Our procedure is thus
efficient and amenable to systems even with all-to-all interactions.Comment: 5 pages, 4 figure
Defining the gap between research and practice in public relations programme evaluation - towards a new research agenda
The current situation in public relations programme evaluation is neatly summarized by McCoy who commented that 'probably the most common buzzwords in public relations in the last ten years have been evaluation and accountability' (McCoy 2005, 3). This paper examines the academic and practitioner-based literature and research on programme evaluation and it detects different priorities and approaches that may partly explain why the debate on acceptable and agreed evaluation methods continues. It analyses those differences and proposes a research agenda to bridge the gap and move the debate forward
Preliminary Experience With 3-Tesla MRI and Cushing\u27s Disease
Because radiographic visualization of a pituitary microadenoma is frequently difficult, we hypothesized that microadenomas associated with Cushing\u27s disease may be better resolved and localized via acquisition with 3-Tesla (3T) compared with standard 1.5-Tesla (1.5T) magnetic resonance imaging (MRI). Five patients (four females, one male; age range, 14 to 50 years old) with endocrine and clinical confirmation of Cushing\u27s disease underwent 1.5T and 3T MRI and corticotropin-releasing hormone stimulation/inferior petrosal sinus sampling (IPSS) as part of their preoperative evaluation. All patients underwent a transnasal trans-sphenoidal pituitary adenomectomy. In two cases, tumor could not be localized on either 1.5T or 3T MRI on the initial radiologist\u27s review. In two other cases, the 1.5T images delineated the tumor location, but it was more clearly defined on 3T MRI. In a fifth case, the 1.5T MRI showed a probable right-sided adenoma. However, on both 3T MRI and at surgical exploration the tumor was localized on the left side. Therefore, in three of five cases, 3T MRI either more clearly defined tumors seen on 1.5T MRI or predicted the location of tumor contrary to the 1.5T images. IPSS identified the correct side of the tumor in two patients, an incorrect location in two patients, and was indeterminate in one patient. In certain cases 3T MRI is a new tool that may ameliorate imaging difficulties associated with adrenocorticotrophic hormone-secreting pituitary adenomas. Its role in the diagnostic evaluation of Cushing\u27s disease will be better defined with further experience. Copyright © 2007 by Thieme Medical Publishers, Inc
On the sampling complexity of open quantum systems
Open quantum systems are ubiquitous in the physical sciences, with widespread
applications in the areas of chemistry, condensed matter physics, material
science, optics, and many more. Not surprisingly, there is significant interest
in their efficient simulation. However, direct classical simulation quickly
becomes intractable with coupling to an environment whose effective dimension
grows exponentially. This raises the question: can quantum computers help model
these complex dynamics? A first step in answering this question requires
understanding the computational complexity of this task. Here, we map the
temporal complexity of a process to the spatial complexity of a many-body state
using a computational model known as the process tensor framework. With this,
we are able to explore the simulation complexity of an open quantum system as a
dynamic sampling problem: a system coupled to an environment can be probed at
successive points in time -- accessing multi-time correlations. The complexity
of multi-time sampling, which is an important and interesting problem in its
own right, contains the complexity of master equations and stochastic maps as a
special case. Our results show how the complexity of the underlying quantum
stochastic process corresponds to the complexity of the associated family of
master equations for the dynamics. We present both analytical and numerical
examples whose multi-time sampling is as complex as sampling from a many-body
state that is classically hard. This also implies that the corresponding family
of master equations are classically hard. Our results pave the way for studying
open quantum systems from a complexity-theoretic perspective, highlighting the
role quantum computers will play in our understanding of quantum dynamics
Discovery of a Radio-Selected z ~ 6 Quasar
We present the discovery of only the second radio-selected, z ~ 6 quasar. We
identified SDSS J222843.54+011032.2 (z=5.95) by matching the optical detections
of the deep Sloan Digital Sky Survey (SDSS) Stripe 82 with their radio
counterparts in the Stripe82 VLA Survey. We also matched the
Canadian-France-Hawaiian Telescope Legacy Survey Wide (CFHTLS Wide) with the
Faint Images of the Radio Sky at Twenty-cm (FIRST) survey but have yet to find
any z ~ 6 quasars in this survey area. The discovered quasar is
optically-faint, z = 22.3 and M_{1450} ~ -24.5, but radio-bright, with a flux
density of f = 0.31mJy and a radio-loudness of R ~ 1100 (where
R = f_{5GHz}/f_{2500}). The i-z color of the discovered quasar places it
outside the color selection criteria for existing optical surveys. We conclude
by discussing the need for deeper wide-area radio surveys in the context of
high-redshift quasars.Comment: 20 pages, 6 figures, and ApJ accepte
Non-Markovian Quantum Process Tomography
Characterisation protocols have so far played a central role in the
development of noisy intermediate-scale quantum (NISQ) computers capable of
impressive quantum feats. This trajectory is expected to continue in building
the next generation of devices: ones that can surpass classical computers for
particular tasks -- but progress in characterisation must keep up with the
complexities of intricate device noise. A missing piece in the zoo of
characterisation procedures is tomography which can completely describe
non-Markovian dynamics. Here, we formally introduce a generalisation of quantum
process tomography, which we call process tensor tomography. We detail the
experimental requirements, construct the necessary post-processing algorithms
for maximum-likelihood estimation, outline the best-practice aspects for
accurate results, and make the procedure efficient for low-memory processes.
The characterisation is the pathway to diagnostics and informed control of
correlated noise. As an example application of the technique, we improve
multi-time circuit fidelities on IBM Quantum devices for both standalone qubits
and in the presence of crosstalk to a level comparable with the fault-tolerant
noise threshold in a variety of different noise conditions. Our methods could
form the core for carefully developed software that may help hardware
consistently pass the fault-tolerant noise threshold
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