1,471 research outputs found
Comment on "Critique and correction of the currently accepted solution of the infinite spherical well in quantum mechanics" by Huang Young-Sea and Thomann Hans-Rudolph
We comment on the paper "Critique and correction of the currently accepted
solution of the infinite spherical well in quantum mechanics" by Huang
Young-Sea and Thomann Hans-Rudolph, EPL 115, 60001 (2016) .Comment: 2 pages; Submitted to the Comments Section of EP
Spinons as Composite Fermions
We show that gauge invariant composites in the fermionic realization of
conformal field theory explicitly exhibit the holomorphic
factorization of the corresponding WZW primaries. In the case we show
that the holomorphic sector realizes the spinon algebra, thus
allowing the classification of the chiral Fock space in terms of semionic
quasi-particle excitations created by the composite fermions.Comment: SU(N)_1 case included. Final version to appear in Mod. Phys. Lett. A.
Latex, 13 page
Understanding the dependence on the pulling speed of the unfolding pathway of proteins
The dependence of the unfolding pathway of proteins on the pulling speed is
investigated. This is done by introducing a simple one-dimensional chain
comprising units, with different characteristic bistable free energies.
These units represent either each of the modules in a modular protein or each
of the intermediate "unfoldons" in a protein domain, which can be either folded
or unfolded. The system is pulled by applying a force to the last unit of the
chain, and the units unravel following a preferred sequence. We show that the
unfolding sequence strongly depends on the pulling velocity . In the
simplest situation, there appears a critical pulling speed : for pulling
speeds
it is the pulled unit that unfolds first. By means of a perturbative expansion,
we find quite an accurate expression for this critical velocity.Comment: accepted for publication in JSTA
Finite-time adiabatic processes: derivation and speed limit
Obtaining adiabatic processes that connect equilibrium states in a given time
represents a challenge for mesoscopic systems. In this paper, we explicitly
show how to build these finite-time adiabatic processes for an overdamped
Brownian particle in an arbitrary potential, a system that is relevant both at
the conceptual and the practical level. This is achieved by jointly engineering
the time evolutions of the binding potential and the fluid temperature.
Moreover, we prove that the second principle imposes a speed limit for such
adiabatic transformations: there appears a minimum time to connect the initial
and final states. This minimum time can be explicitly calculated for a general
compression/decompression situation.Comment: Main text: 5 pages; 18 pages with appendices and references; major
revision with results for a general non-linear potential and study of
fluctuations added; Physical Review E in pres
Lattice models for granular-like velocity fields: Finite-size effects
Long-range spatial correlations in the velocity and energy fields of a
granular fluid are discussed in the framework of a 1d lattice model. The
dynamics of the velocity field occurs through nearest-neighbour inelastic
collisions that conserve momentum but dissipate energy. A set of equations for
the fluctuating hydrodynamics of the velocity and energy mesoscopic fields give
a first approximation for (i) the velocity structure factor and (ii) the
finite-size correction to the Haff law, both in the homogeneous cooling regime.
At a more refined level, we have derived the equations for the two-site
velocity correlations and the total energy fluctuations. First, we seek a
perturbative solution thereof, in powers of the inverse of system size. On the
one hand, when scaled with the granular temperature, the velocity correlations
tend to a stationary value in the long time limit. On the other hand, the
scaled standard deviation of the total energy diverges, that is, the system
shows multiscaling. Second, we find an exact solution for the velocity
correlations in terms of the spectrum of eigenvalues of a certain matrix. The
results of numerical simulations of the microscopic model confirm our
theoretical results, including the above described multiscaling phenomenon
Experience of a Medical School in the Philippines on the Sudden Shift to Online Learning amidst COVID-19
Introduction
The COVID-19 pandemic forced educational institutions to adapt to a full online learning environment. Medical schools in particular were disrupted by this shift since the majority of the learning objectives, skills, and necessary competencies are learned through classroom and hospital face-to-face activities.
Objective
The purpose of this paper is to describe the experiences of a medical school in the country as it navigated the sudden shift to full online learning vis-Ă -vis a framework on the barriers and solutions to online learning.
Method
This is a descriptive paper written from the perspective and observations of an administrator who participated in crafting the immediate response of the school to the sudden shift to online delivery and who worked with the stakeholders of the Ateneo School of Medicine and Public Health (ASMPH).
Results
To address concerns on time, skills and infrastructure, the school reprioritized its learning objectives for the remainder of the school year. It conducted in-service sessions for faculty while also immediately setting up a learning management system and a technical support team that was available on demand. Strategies employed included a deliberate switch to asynchronous learning, curation of content and creativity in delivery and assessment, and the reshaping of the management and public health activities into the online platform. To manage attitudes and provide institutional support, the school worked collaboratively with stakeholders and transformed its traditional support services of campus ministry, counselling, formation, and physical and mental health to be readily available online.
Conclusion
We described the experience of ASMPH when medical schools were forced to completely shift to online delivery of their programs because of the pandemic. We identified the barriers and solutions of online learning in medical education. The unique context of the ASMPH for having a dual degree in medicine and management; having an inter-disciplinal, non-departmentalized set-up at each year level; and, possessing the traditions of Jesuit education were instrumental in the school’s ability to navigate this sudden shift
Feynman diagrams with the effective action
A derivation is given of the Feynman rules to be used in the perturbative
computation of the Green's functions of a generic quantum many-body theory when
the action which is being perturbed is not necessarily quadratic. Some
applications are discussed.Comment: Extended revised version. RevTex, 19 pages, 10 figure
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