6,444 research outputs found
Service-Learning in Catholic Higher Education and Alternative Approaches Facing the COVID-19 Pandemic
Drawing on a review of the literature on service-learning in Catholic higher education and the development of online service-learning, as well as an empirical case study of 2020 Vincentian Service Day at DePaul University, this article examines an alternative way to develop service-learning in Catholic schools in response to the reality and needs of the world in front of us. Service-learning is widely practiced in higher education institutions and plays an essential role in Catholic schools as it integrates students’ faith, morals, and spiritual growth with social justice commitments. School closures due to COVID-19 significantly impede service-learning. However, a successful case of virtual service-learning design and practice at DePaul University in May 2020 can provide insights and prospects of developing service-learning during and beyond the pandemic. This article highlights the importance of service-learning in Catholic higher education and explores the feasibility of developing virtual service-learning during this unprecedented time and moving forward
Assessment of Cardiac Function and Energetics in Isolated Mouse Hearts Using 31P NMR Spectroscopy
Bioengineered mouse models have become powerful research tools in determining causal relationships between molecular alterations and models of cardiovascular disease. Although molecular biology is necessary in identifying key changes in the signaling pathway, it is not a surrogate for functional significance. While physiology can provide answers to the question of function, combining physiology with biochemical assessment of metabolites in the intact, beating heart allows for a complete picture of cardiac function and energetics. For years, our laboratory has utilized isolated heart perfusions combined with nuclear magnetic resonance (NMR) spectroscopy to accomplish this task. Left ventricular function is assessed by Langendorff-mode isolated heart perfusions while cardiac energetics is measured by performing 31P magnetic resonance spectroscopy of the perfused hearts. With these techniques, indices of cardiac function in combination with levels of phosphocreatine and ATP can be measured simultaneously in beating hearts. Furthermore, these parameters can be monitored while physiologic or pathologic stressors are instituted. For example, ischemia/reperfusion or high workload challenge protocols can be adopted. The use of aortic banding or other models of cardiac pathology are apt as well. Regardless of the variants within the protocol, the functional and energetic significance of molecular modifications of transgenic mouse models can be adequately described, leading to new insights into the associated enzymatic and metabolic pathways. Therefore, 31P NMR spectroscopy in the isolated perfused heart is a valuable research technique in animal models of cardiovascular disease
Topological nodal line in ZrTe demonstrated by nuclear magnetic resonance
In this work, we report nuclear magnetic resonance (NMR) combined with
density functional theory (DFT) studies of the transition metal dichalcogenide
ZrTe. The measured NMR shift anisotropy reveals a quasi-2D behavior
connected to a topological nodal line close to the Fermi level. With the
magnetic field perpendicular to the ZrTe layers, the measured shift can be
well-fitted by a combination of enhanced diamagnetism and spin shift due to
high mobility Dirac electrons. The spin-lattice relaxation rates with external
field both parallel and perpendicular to the layers at low temperatures match
the expected behavior associated with extended orbital hyperfine interaction
due to quasi-2D Dirac carriers. In addition, calculated band structures also
show clear evidence for the existence of nodal line in ZrTe between
and A. For intermediate temperatures, there is a sharp reduction in
spin-lattice relaxation rate which can be explained as due to a reduced
lifetime for these carriers, which matches the reported large change in
mobility in the same temperature range. Above 200 K, the local orbital
contribution starts to dominate in an orbital relaxation mechanism revealing
the mixture of atomic functions.Comment: 9 pages, 5 figure
Dirac electron behavior and NMR evidence for topological band inversion in ZrTe5
We report Te NMR measurements of the topological quantum material
ZrTe. Spin-lattice relaxation results, well-explained by a theoretical
model of Dirac electron systems, reveal that the topological characteristic of
ZrTe is -dependent, changing from weak topological insulator to strong
topological insulator as temperature increases. Electronic structure
calculations confirm this ordering, the reverse of what has been proposed. NMR
results demonstrate a gapless Dirac semimetal state occurring at a Lifshitz
transition temperature, K in our crystals. We demonstrate that the
changes in NMR shift at also provide direct evidence of band inversion
when the topological phase transition occurs.Comment: 5 pages, 4 figure
Gap-opening transition in Dirac semimetal ZrTe
We apply Te nuclear magnetic resonance (NMR) spectroscopy to
investigate the Dirac semimetal ZrTe. With the NMR magnetic field parallel
to the -axis, we observe significant quantum magnetic effects. These include
an abrupt drop at 150 K in spin-lattice relaxation rate. This corresponds to a
gap-opening transition in the Dirac carriers, likely indicating the onset of
excitonic pairing. Below 50 K, we see a more negative shift for the Te
bridging site indicating the repopulation of Dirac levels with spin polarized
carriers at these temperatures. This is the previously reported 3D quantum Hall
regime; however, we see no sign of a charge density wave as has been proposed.Comment: 5 pages, 4 figure
Endeavoring a critical and thoughtful response during and beyond COVID-19: Community-Based Justice Work in a Catholic University
The COVID-19 pandemic and resulting quarantines around the globe have required social justice educators to respond to the unprecedented challenges and the needs of the communities they serve more than ever before. This article explores how educators in a Catholic University conducted community-based justice work in response to the challenges of the pandemic by integrating educators’ solidarity with faith and social justice commitments. We introduce the Lift as You Climb (Lift) project as one example of our approach with Catholic value of promoting human rights and common good. We offer reflections on challenges and successes of community-based programming, considerations of issues of equity and access to educational resources, as well as recommendations for educators’ next actions, in order to offer insight into the implementation of community-based justice work during and beyond COVID-19
Robust 6D Object Pose Estimation by Learning RGB-D Features
Accurate 6D object pose estimation is fundamental to robotic manipulation and
grasping. Previous methods follow a local optimization approach which minimizes
the distance between closest point pairs to handle the rotation ambiguity of
symmetric objects. In this work, we propose a novel discrete-continuous
formulation for rotation regression to resolve this local-optimum problem. We
uniformly sample rotation anchors in SO(3), and predict a constrained deviation
from each anchor to the target, as well as uncertainty scores for selecting the
best prediction. Additionally, the object location is detected by aggregating
point-wise vectors pointing to the 3D center. Experiments on two benchmarks:
LINEMOD and YCB-Video, show that the proposed method outperforms
state-of-the-art approaches. Our code is available at
https://github.com/mentian/object-posenet.Comment: Accepted at ICRA 202
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