1,903 research outputs found
Examining Collegiality and Social Justice in Academia and the Private Sector: an Exploratory SYMLOG Analysis
This research compares the perceptions of the private sector, high-technology employees to the perceptions of university faculty members regarding organizational culture, social justice and collegiality concepts. The SYMLOG assessment technique was used to record the perceptions of respondents to four different concepts of organizational culture, two different aspects of social justice and two measures of collegiality. Comparative findings of gender differences across the eight concepts raise key organizational culture, legal, measurement, governance, and social policy issues for academia and high tech organizations. The development of a conceptual framework to guide future research and a blueprint to discuss desired organizational change are highlighted
Optimality of feedback control for qubit purification under inefficient measurement
A quantum system may be purified, i.e., projected into a pure state, faster if one applies feedback operations during the measurement process. However, the existing results suggest that such an enhancement is only possible when the measurement efficiency exceeds 0.5, which is difficult to achieve experimentally. We address the task of finding the global optimal feedback control for purifying a single qubit in the presence of measurement inefficiency. We use the Bloch vector length, a more physical and practical quantity than purity, to assess the quality of the state, and employ a backward-iteration algorithm to find the globally optimal strategy. Our results show that a speedup is available for quantum efficiencies well below 0.5, which opens the possibility of experimental implementation in existing systems
Number squeezed and fragmented states of strongly interacting bosons in a double well
We present a systematic study of the phenomena of number squeezing and
fragmentation for a repulsive Bose-Einstein condensate (BEC) in a three
dimensional double well potential over a range of interaction strengths and
barrier heights, including geometries that exhibit appreciable overlap in the
one-body wavefunctions localized in the left and right wells. We compute the
properties of the condensate with numerically exact, full dimensional path
integral ground state (PIGS) Quantum Monte Carlo simulations and compare with
results obtained from using two- and eight-mode truncated basis models. The
truncated basis models are found to agree with the numerically exact PIGS
simulations for weak interactions, but fail to correctly predict the amount of
number squeezing and fragmentation exhibited by the PIGS simulations for strong
interactions. We find that both number squeezing and fragmentation of the BEC
show non-monotonic behavior at large values of interaction strength a. The
number squeezing shows a universal scaling with the product of number of
particles and interaction strength (Na) but no such universal behavior is found
for fragmentation. Detailed analysis shows that the introduction of repulsive
interactions not only suppresses number fluctuations to enhance number
squeezing, but can also enhance delocalization across wells and tunneling
between wells, each of which may suppress number squeezing. This results in a
dynamical competition whose resolution shows a complex dependence on all three
physical parameters defining the system: interaction strength, number of
particles, and barrier height.Comment: 33 pages, 21 figures. Submitted for publication in Physical Review
Competition, Conflict, and Compromise: Three Discourses Used by Irrigators in England and Their Implications for the CoManagement of Water Resources
In this paper we use discourse analysis to explore the current dynamic that exists among farmer irrigators in England, and between irrigators and water managers in order to understand the potential for co-management to develop. To do this we employ two concepts from the field of critical discursive psychology – 'interpretive repertoires' and 'subject positions' – and apply them to a qualitative analysis of 20 interviews with farmers who are members of irrigator groups and two focus group discussions with farmers thinking about forming an irrigator group. The findings reveal that the participants drew upon three interpretive repertoires when talking about the relationship between farming and water resources management, namely the 'competition', 'conflict', and 'compromise' repertoires, with the latter being the least dominant. We situate the repertoires in their wider historical context to reveal the ideological forces at play, and conclude that the relative dominance of the competition and conflict repertoires serve as a barrier to co-management. In particular, this is because they engender low levels of trust and reinforce a power dynamic that favours individualism and opposition. At the same time, the less-dominant compromise repertoire challenges the power of the other two, providing some hope of achieving more participatory forms of water resources management in the future. To this end, we discuss how the restructuring of current agri-environment schemes and government water programmes may be used to promote the adoption and institutionalisation of the compromise repertoire in order to facilitate the emergence of co-management
Power-Sharing in the English Lowlands? The Political Economy of Farmer Participation and Cooperation in Water Governance
Participatory and cooperative forms of water governance have become regular features of government discourse and stated policy objectives in England. We consider this aspiration from the perspective of farmers in the English lowlands, by analysing the current power dynamic that exists among these farmers, and between them and the key stakeholders involved in water management. To do this we undertake a political economy analysis that places lowland farming and water governance within the evolution of historical processes that, over time, have influenced the ability of farmers to participate in the governance of their water environment. These historical developments are interpreted through the lens of the Power Cube, an analytical tool for thinking about the interplay between different forms of power operating in different types of spaces and at different levels of governance. Our findings reveal that, despite there being a number of structural changes that provide lowland farmers with the opportunity to participate and cooperate in water governance, three distinct barriers stand in the way. These relate to the power 'within' these farmers, which continues to align with a productivist ideology founded on individualism and competition, often at the expense of the environment; the power that government water managers still exercise 'over' farmers instead of 'with' them; and the relationship between lowland farming and environmental interests, where historically the two sides’ power 'to' act has been diametrically opposed. The findings point to the importance of developing suitable programmes designed to support and incentivize farmer participation and cooperation
What is the optimal way to prepare a Bell state using measurement and feedback?
Recent work has shown that the use of quantum feedback can significantly enhance both the speed and success rate of measurement-based remote entanglement generation, but it is generally unknown what feedback protocols are optimal for these tasks. Here we consider two common measurements that are capable of projecting into pairwise entangled states, namely half- and full-parity measurements of two qubits, and determine in each case a globally optimal protocol for generation of entanglement. For the half-parity measurement, we rederive a previously described protocol using more general methods and prove that it is globally optimal for several figures of merit, including maximal concurrence or fidelity and minimal time to reach a specified concurrence or fidelity. For the full-parity measurement, we derive a protocol for rapid entanglement generation related to that of (Hill, Ralph, Phys. Rev. A 77, 014305), and then map the dynamics of the concurrence of the state to the Bloch vector length of an effective qubit. This mapping allows us to prove several optimality results for feedback protocols with full-parity measurements. We further show that our full-parity protocol transfers entanglement optimally from one qubit to the other amongst all measurement-based schemes. The methods developed here will be useful for deriving feedback protocols and determining their optimality properties in many other quantum systems subject to measurement and unitary operations
The Creative Work Environment: Manager and Employee Perceptions of Factors that lnfluence Creativity Within Land·Grant Communication Units
According to research, environmental factors have the potential to inhibit or enhance creativity, particularly in a work setting
The Association Between the Long-Term Change in Directly Measured Cardiorespiratory Fitness and Mortality Risk
Introduction: There is a strong inverse association between cardiorespiratory fitness (CRF) and mortality outcomes. This relationship has predominantly been assessed cross-sectionally, however low CRF is a modifiable risk factor, thus assessing this association using a single baseline measure may be sub-optimal. Purpose: To examine the association of the long-term change in CRF, measured using cardiopulmonary exercise testing (CPX) with all-cause and disease-specific mortality.
Methods: Participants included 833 apparently healthy men and women (42.9±10.8 years) who underwent two maximal CPXs, the second CPX being ≥ 1 year following the baseline assessment. Participants were followed for 17.7 ± 11.8 years for allcause, cardiovascular disease (CVD), and cancer mortality. Cox-proportional hazard models were performed to determine the association between the change in CRF, computed as visit 1 (V1) peak oxygen consumption (VO2peak (ml·kg-1·min-1)) – visit 2 (V2) VO2peak, and mortality outcomes.
Results: During follow-up, 172 participants died. Overall, the change in CPX-derived CRF was inversely related to all-cause, CVD, and cancer mortality (p\u3c0.05). Each 1 ml·kg-1·min-1 increase was associated with a 10.8, 14.7, and 15.9% reductions in allcause, CVD, and cancer mortality, respectively. The inverse relationship between CRF and all-cause mortality remained significant (p\u3c0.05) when men and women were examined independently, after adjusting for years since first CPX, baseline VO2peak, and age.
Conclusion: Long-term changes in CRF were inversely related to mortality outcomes, and mortality was better predicted by CRF measured at subsequent examination than baseline CRF. These findings support the recent American Heart Association scientific statement advocating CRF as a clinical vital sign that should be assessed routinely in clinical practice, as well as support regular participation in physical activity to maintain adequate CRF levels across the lifespan
Dynamics of photosynthetic light harvesting systems interacting with N-photon Fock states
We develop a method to simulate the excitonic dynamics of realistic
photosynthetic light harvesting systems including non-Markovian coupling to
phonon degrees of freedom, under excitation by N-photon Fock state pulses. This
method combines the input-output formalism and the hierarchical equations of
motion (HEOM) formalism into a double hierarchy of coupled linear equations in
density matrices. We show analytically that, under weak field excitation
relevant to natural photosynthesis conditions, an N-photon Fock state input and
a corresponding coherent state input give rise to equal density matrices in the
excited manifold. However, an important difference is that an N-photon Fock
state input has no off-diagonal coherence between the ground and excited
subspaces, in contrast with the coherences created by a coherent state input.
We derive expressions for the probability to absorb a single Fock state photon,
with or without the influence of phonons. For short pulses (or equivalently,
wide bandwidth pulses), we show that the absorption probability has a universal
behavior that depends only upon a system-dependent effective energy spread
parameter {\Delta} and an exciton-light coupling constant {\Gamma}. This holds
for a broad range of chromophore systems and for a variety of pulse shapes. We
also analyse the absorption probability in the opposite long pulses (narrow
bandwidth) regime. We also derive an expression for the long time emission rate
in the presence of phonons and use it to study the difference between
collective versus independent emission. Finally, we present a numerical
simulation for the LHCII monomer (14-mer) system under single photon excitation
that illustrates the use of the double hierarchy for calculation of Fock state
excitation of a light harvesting system including chromophore coupling to a
non-Markovian phonon bath.Comment: 54 pages, 17 figures; revised abstract, added acknowledgement
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