8,053 research outputs found
A molecular dynamics computer simulation study of room-temperature ionic liquids. I. Equilibrium solvation structure and free energetics
Solvation in 1-ethyl-3-methylmidazolium chloride and in
1-ethyl-3-methylimidazolium hexafluorophosphate near equilibrium is
investigated via molecular dynamics computer simulations with diatomic and
benzenelike molecules employed as probe solutes. It is found that
electrostriction plays an important role in both solvation structure and free
energetics. The angular and radial distributions of cations and anions become
more structured and their densities near the solute become enhanced as the
solute charge separation grows. Due to the enhancement in structural rigidity
induced by electrostriction, the force constant associated with solvent
configuration fluctuations relevant to charge shift and transfer processes is
also found to increase. The effective polarity and reorganization free energies
of these ionic liquids are analyzed and compared with those of highly polar
acetonitrile. Their screening behavior of electric charges is also
investigated.Comment: 12 page
Analytic study of the three-urn model for separation of sand
We present an analytic study of the three-urn model for separation of sand.
We solve analytically the master equation and the first-passage problem. We
find that the stationary probability distribution obeys the detailed balance
and is governed by the {\it free energy}. We find that the characteristic
lifetime of a cluster diverges algebraically with exponent 1/3 at the limit of
stability.Comment: 5pages, 4 figures include
Fragility, Stokes-Einstein violation, and correlated local excitations in a coarse-grained model of an ionic liquid
Dynamics of a coarse-grained model for the room-temperature ionic liquid,
1-ethyl-3-methylimidazolium hexafluorophosphate, couched in the united-atom
site representation are studied via molecular dynamics simulations. The
dynamically heterogeneous behavior of the model resembles that of fragile
supercooled liquids. At or close to room temperature, the model ionic liquid
exhibits slow dynamics, characterized by nonexponential structural relaxation
and subdiffusive behavior. The structural relaxation time, closely related to
the viscosity, shows a super-Arrhenius behavior. Local excitations, defined as
displacement of an ion exceeding a threshold distance, are found to be mainly
responsible for structural relaxation in the alternating structure of cations
and anions. As the temperature is lowered, excitations become progressively
more correlated. This results in the decoupling of exchange and persistence
times, reflecting a violation of the Stokes-Einstein relation.Comment: Published on the Phys. Chem. Chem. Phys. websit
Analytic study of the urn model for separation of sand
We present an analytic study of the urn model for separation of sand recently
introduced by Lipowski and Droz (Phys. Rev. E 65, 031307 (2002)). We solve
analytically the master equation and the first-passage problem. The analytic
results confirm the numerical results obtained by Lipowski and Droz. We find
that the stationary probability distribution and the shortest one among the
characteristic times are governed by the same free energy. We also analytically
derive the form of the critical probability distribution on the critical line,
which supports their results obtained by numerically calculating Binder
cumulants (cond-mat/0201472).Comment: 6 pages including 3 figures, RevTe
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Emergency Medicine Palliative Care Access (EMPallA): Protocol for a multicentre randomised controlled trial comparing the effectiveness of specialty outpatient versus nurse-led telephonic palliative care of older adults with advanced illness
Introduction Emergency department (ED)-initiated palliative care has been shown to improve patient-centred outcomes in older adults with serious, life-limiting illnesses. However, the optimal modality for providing such interventions is unknown. This study aims to compare nurse-led telephonic case management to specialty outpatient palliative care for older adults with serious, life-limiting illness on: (1) quality of life in patients; (2) healthcare utilisation; (3) loneliness and symptom burden and (4) caregiver strain, caregiver quality of life and bereavement. Methods and analysis This is a protocol for a pragmatic, multicentre, parallel, two-arm randomised controlled trial in ED patients comparing two established models of palliative care: nurse-led telephonic case management and specialty, outpatient palliative care. We will enrol 1350 patients aged 50+ years and 675 of their caregivers across nine EDs. Eligible patients: (1) have advanced cancer (metastatic solid tumour) or end-stage organ failure (New York Heart Association class III or IV heart failure, end-stage renal disease with glomerular filtration rate /min/m2, or global initiative for chronic obstructive lung disease stage III, IV or oxygen-dependent chronic obstructive pulmonary disease); (2) speak English; (3) are scheduled for ED discharge or observation status; (4) reside locally; (5) have a working telephone and (6) are insured. Patients will be excluded if they: (1) have dementia; (2) have received hospice care or two or more palliative care visits in the last 6 months or (3) reside in a long-term care facility. We will use patient-level block randomisation, stratified by ED site and disease. Effectiveness will be compared by measuring the impact of each intervention on the specified outcomes. The primary outcome will measure change in patient quality of life. Ethics and dissemination Institutional Review Board approval was obtained at all study sites. Trial results will be submitted for publication in a peer-reviewed journal
Identifying policy frames through semantic network analysis : an examination of nuclear energy policy across six countries
This study uses semantic network analysis to investigate nuclear energy policy frames in six countries: USA, UK, Germany, France, Japan, and South Korea. It is suggested that semantic network analysis represents a useful tool to investigate policy frames in complex policy environments. The discourse of top-level decision-makers is analyzed to highlight similarities and differences in policy frames and to identify the key policy arguments in the integrated network of all six countries. In total, 14 major policy arguments are identified, which relate to the three major frames of energy security, clean energy, and nuclear safety, along with the meta-issue of economic growth. There are differences in the degree of emphasis on each of the frames in the six countries, and Germany can be seen to have diverged the most following the Fukushima accident, as the emphasis is on clean energy, to the exclusion of the other frames. In contrast, both the USA and Japan have framed the issues primarily in terms of nuclear safety and energy security, while the UK and France have stressed the economic growth frame, and Korea has prioritized nuclear safety
The Digital Revolution: Internet of Things, 5G, and Beyond
Over the past decade, the world has been swimming in an ocean of technology, which has opened the doors for many opportunities as industrial boundaries continue to change. “Blue oceans” have opened their waters for new industries such as social networking, smart technology, mobility, and big data. Looking forward, new trends such as the Internet of things (IoT) and technology advancements towards 5G mobile technology are paving the way for new markets and industries along with further advancements in big data. A panel discussion consisting of industry leaders and researchers addressed these topics and the emerging technologies that are changing the world
Electron-hole asymmetry in Co- and Mn-doped SrFe2As2
Phase diagram of electron and hole-doped SrFe2As2 single crystals is
investigated using Co and Mn substitution at the Fe-sites. We found that the
spin-density-wave state is suppressed by both dopants, but the superconducting
phase appears only for Co (electron)-doping, not for Mn (hole)-doping. Absence
of the superconductivity by Mn-doping is in sharp contrast to the hole-doped
system with K-substitution at the Sr sites. Distinct structural change, in
particular the increase of the Fe-As distance by Mn-doping is important to have
a magnetic and semiconducting ground state as confirmed by first principles
calculations. The absence of electron-hole symmetry in the Fe-site-doped
SrFe2As2 suggests that the occurrence of high-Tc superconductivity is sensitive
to the structural modification rather than the charge doping.Comment: 7 pages, 6 figure
Emergency Medicine Palliative Care Access (EMPallA): Preliminary Data from a Multi-Center Randomized Controlled Trial
Introduction: Emergency department (ED)-initiated palliative care has been shown to improve patient-centered outcomes in older adults with serious illnesses, but the optimal modality for providing such interventions is unknown. The EMPallA trial compares nurse-led, telephonic case management with specialty, outpatient palliative care on: 1) patient quality of life (QOL); 2) healthcare utilization; 3) loneliness and symptom burden; and 4) caregiver strain, QOL, and bereavement.
Objective: Summarize preliminary demographic and QOL data for the EMPallA cohort.
Methods: A pragmatic, parallel, two-arm randomized controlled trial is enrolling 1350 ED patients across 9 EDs over 3 years to compare the effectiveness of palliative care models. Eligible patients have end-stage heart failure, renal disease, chronic obstructive pulmonary disease (COPD), or cancer. Baseline data is collected at bedside using surveys. Functional Assessment of Cancer Therapy - General (FACT-G) QOL scores are rescaled into T-scores based on general US and cancer patient samples, standardized with mean 50 and standard deviation 10.
Results: 138 patients enrolled from April 16 to October 16, 2018. Average age was 69 years; 55% were female, and 55% were white. Advanced cancer was most prevalent (48%), followed by heart failure (24%), COPD (23%), and end-stage renal disease (15%). Average FACT-G T-scores were 41 (general population) and 40 (cancer patients), which are below population means of 50 by more than 5, a clinically-meaningful difference.
Discussion: This gender-balanced, racially-diverse cohort stands to benefit in QOL from palliative care. When trial enrollment and follow-up are complete, the impact of interventions can be assessed
The Interaction of Virtual Reality, Blockchain, and 5G New Radio: Disrupting Business and Society
The three cutting-edge technologies virtual reality, blockchain, and 5G have increasingly attracted public attention. While virtual reality became a popular concept in the 1990s, recent technological advances and decreased costs have created a resurgence in the technology. With significant funding and early adoption, blockchain and 5G have begun to make their mark on the world. Each technology alone may disrupt business and society, but, together, they provide multiple opportunities. In this paper, we summarize a 2018 Association for Information Systems Americas Conference on Information Systems (AMCIS) panel session with IS researchers and industry practitioners that tackled important topics related to these technologies. In particular, the panel made the case for IS research that focuses on topics that emerge when these technologies intersect. Each panelist presented their perspectives based on their experience and knowledge along with current issues and future directions. This topic has significant business implications as practitioners continue to note their advancements and develop strategies to adapt in a rapidly changing environment. The topic also has implications for future research as these technologies continue to become more prevalent
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