169 research outputs found
Rigorous wave function embedding with dynamical fluctuations
The dynamical fluctuations in approaches such as dynamical mean-field theory
(DMFT) allow for the self-consistent optimization of a local fragment,
hybridized with a true correlated environment. We show that these correlated
environmental fluctuations can instead be efficiently captured in a wave
function perspective in a computationally cheap, frequency-independent,
zero-temperature approach. This allows for a systematically improvable,
short-time wave function analogue to DMFT, which entails a number of
computational and numerical benefits. We demonstrate this approach to solve the
correlated dynamics of the paradigmatic Bethe lattice Hubbard model, as well as
detailing cluster extensions in the one-dimensional Hubbard chain where we
clearly show the benefits of this rapidly convergent description of correlated
environmental fluctuations
On the calculation of complete dissociation curves of closed-shell pseudo-onedimensional systems through the multireference method of increments
The Method of Increments (MoI) has been employed using a multireference
approach to calculate the dissociation curve of beryllium ring-shaped clusters
Be of different sizes. Benchmarks obtained through different single and
multireference methods including the ab initio Density Matrix Renormalization
Group (DMRG) were used to verify the validity of the MoI truncation which
showed a reliable behavior for the whole dissociation curve. Moreover we
investigated the size dependence of the correlation energy at different
distances in order to extrapolate the values for the periodic chain and to
discuss the transition from a metal-like to a insulating-like behavior of the
wave function through quantum chemical considerations
Investigation of metal-insulator like transition through the ab initio density matrix renormalization group approach
We have studied the Metal-Insulator like Transition (MIT) in lithium and
beryllium ring-shaped clusters through ab initio Density Matrix Renormalization
Group (DMRG) method. Performing accurate calculations for different interatomic
distances and using Quantum Information Theory (QIT) we investigated the
changes occurring in the wavefunction between a metallic-like state and an
insulating state built from free atoms. We also discuss entanglement and
relevant excitations among the molecular orbitals in the Li and Be rings and
show that the transition bond length can be detected using orbital entropy
functions. Also, the effect of different orbital basis on the effectiveness of
the DMRG procedure is analyzed comparing the convergence behavior.Comment: 12 pages, 14 figure
When Priests Forgot About God: An Analysis of the Catholic Church\u27s Role in Genocide
The Catholic Church in Rwanda for more than a century was a witness to the atrocities of genocide. One million Rwandans died in 100 days while many Catholic priests and nuns stood by offering no assistance. Others participated in the slaughter. The majority of those killed were killed in churches or on church grounds. Since Belgium\u27s acquisition of Rwanda, there have been ties between the Catholic Church and the government of Rwanda. The Catholic Church blamed Belgium for the ethnic class designations and for disturbing the native culture. The Church and priests, however, remained silent and maintained their silence to keep teaching and practicing in Rwanda. While over 60,000 were charged in connection with the genocide, imprisoned for hate crimes, and later released, fewer than twenty, including priests and nuns, were tried and sentenced.
KEYWORDS: Catholic Church, Priests, Rwanda, Genocid
Calculation of the static and dynamical correlation energy of pseudo-one-dimensional beryllium systems via a many-body expansion
Low-dimensional beryllium systems constitute interesting case studies for the
test of correlation methods because of the importance of both static and
dynamical correlation in the formation of the bond. Aiming to describe the
whole dissociation curve of extended Be systems we chose to apply the method of
increments (MoI) in its multireference (MR) formalism. However, in order to do
so an insight into the wave function was necessary. Therefore we started by
focusing on the description of small Be chains via standard quantum chemical
methods and gave a brief analysis of the main characteristics of their wave
functions. We then applied the MoI to larger beryllium systems, starting from
the Be6 ring. First, the complete active space formalism (CAS-MoI) was employed
and the results were used as reference for local MR calculations of the whole
dissociation curve. Despite this approach is well established for the
calculation of systems with limited multireference character, its application
to the description of whole dissociation curves still requires further testing.
After discussing the role of the basis set, the method was finally applied to
larger rings and extrapolated to an infinite chain
Life Satisfaction, Social Identity, and Household Work: An Intersectionality Perspective
The aim of the current study was to extend the understanding of life satisfaction by incorporating intersectionality and household work, both logical and necessary additions that have been previously overlooked in the satisfaction literature. Findings suggest that intersectionality may help provide a more detailed understanding of overall life satisfaction. When other relevant psychological constructs were accounted for, the intersections among gender, income, and household work hours provided additional (although modest) predictive power for differences in life satisfaction. The current study addresses the call for increased intersectional research in the behavioral sciences with acceptable generalizability through the use of a nationally representative sample (Cole, 2009; Phoenix, 2006; Warner, 2008; Weldon, 2005). Increased consideration and awareness of intersectionality and its influence on the way in which we interact with and interpret the world around us should be a primary goal across the psychological discipline
Energy-weighted density matrix embedding of open correlated chemical fragments
We present a multi-scale approach to efficiently embed an ab initio
correlated chemical fragment described by its energy-weighted density matrices,
and entangled with a wider mean-field many-electron system. This approach,
first presented in Phys. Rev. B, 98, 235132 (2018), is here extended to account
for realistic long-range interactions and broken symmetry states. The scheme
allows for a systematically improvable description in the range of correlated
fluctuations out of the fragment into the system, via a self-consistent
optimization of a coupled auxiliary mean-field system. It is discussed that the
method has rigorous limits equivalent to existing quantum embedding approaches
of both dynamical mean-field theory, as well as density matrix embedding
theory, to which this method is compared, and the importance of these
correlated fluctuations is demonstrated. We derive a self-consistent local
energy functional within the scheme, and demonstrate the approach for Hydrogen
rings, where quantitative accuracy is achieved despite only a single atom being
explicitly treated.Comment: 14 pages, 8 figure
Successful Patient Participation in Acute Hospital Physical Therapy
Purpose/Hypothesis: Research has demonstrated that physical therapy plays a crucial role in patient recovery in the acute hospital setting. Despite known benefits, scheduled sessions do not always occur and are called nontreatment (NT) events. Reported NT ranges from 15% to 26% of scheduled sessions. Previous studies have found an association between NT and patient diagnosis as well as between NT and day of the week on which treatment was scheduled. Identifying additional factors that affect NT is important if therapists and administrators are to make improvements. The purpose of this study is to determine if an association exists between physical therapist attributes and NT risk among their patients. A secondary aim of this study is to confirm that patient diagnosis and day of the week change the odds of NT, as those results were only seen in one prior study at a single hospital. Subjects: 36 physical therapists and 623 of their consecutive adult patients who were scheduled for physical therapy during their hospital stay. Materials/Methods: A cross-sectional, medical record review of 623 consecutive patients over 3 months scheduled for 2,419 physical therapy sessions. Results: The overall NT proportion of planned therapy sessions was 13.2%, it was 4.8% for the first scheduled session, and 16.1% among remaining sessions. NT proportions for individual therapists ranged from 1.7% to 22.6% among therapists with at least 30 planned sessions. When male patients were scheduled for therapy with a female therapist, 25.5% of sessions resulted in NT. NT was 15.0% when female patients were scheduled for therapy with a male therapist, and 16.1% when the sex of the patient and therapist matched. As in previous studies, patients were less likely to experience NT if they had a musculoskeletal condition. Conclusions: Findings from previous studies that patient diagnoses were associated with NT were confirmed. While the mean proportion of NT was around 15%, individual physical therapists may be much higher or lower. The sex of patients and therapists was associated with significantly different NT proportions and should be evaluated further. Future research efforts should include other therapist traits that may influence NT. Clinical Relevance: With a better understanding of reasons for NT, therapists and administrators may be able to match patients with therapists most likely to be successful in treatment. The relationship between sex of the patient and therapist may have an impact on the occurrence of NT. Hospital and rehabilitation department policies need to be evaluated in an effort to reduce the higher percentage of NT among patients without musculoskeletal diagnoses
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