7 research outputs found
Energy transport between heat baths with oscillating temperatures
Energy transport is a fundamental physical process that plays a prominent
role in the function and performance of myriad systems and technologies. Recent
experimental measurements have shown that subjecting a macroscale system to a
time-periodic temperature gradient can increase thermal conductivity in
comparison to a static temperature gradient. Here, we theoretically examine
this mechanism in a nanoscale model by applying a stochastic Langevin framework
to describe the energy transport properties of a particle connecting two heat
baths with different temperatures, where the temperature difference between
baths is oscillating in time. Analytical expressions for the energy flux of
each heat bath and for the system itself are derived for the case of a free
particle and a particle in a harmonic potential. We find that dynamical effects
in the energy flux induced by temperature oscillations give rise to complex
energy transport hysteresis effects. The presented results suggest that
applying time-periodic temperature modulations is a potential route to control
energy storage and release in molecular devices and nanosystems
Data-driven methods for diffusivity prediction in nuclear fuels
The growth rate of structural defects in nuclear fuels under irradiation is
intrinsically related to the diffusion rates of the defects in the fuel
lattice. The generation and growth of atomistic structural defects can
significantly alter the performance characteristics of the fuel. This
alteration of functionality must be accurately captured to qualify a nuclear
fuel for use in reactors. Predicting the diffusion coefficients of defects and
how they impact macroscale properties such as swelling, gas release, and creep
is therefore of significant importance in both the design of new nuclear fuels
and the assessment of current fuel types. In this article, we apply data-driven
methods focusing on machine learning (ML) to determine various diffusion
properties of two nuclear fuels, uranium oxide and uranium nitride. We show
that using ML can increase, often significantly, the accuracy of predicting
diffusivity in nuclear fuels in comparison to current analytical models. We
also illustrate how ML can be used to quickly develop fuel models with
parameter dependencies that are more complex and robust than what is currently
available in the literature. These results suggest there is potential for ML to
accelerate the design, qualification, and implementation of nuclear fuels
Socializing One Health: an innovative strategy to investigate social and behavioral risks of emerging viral threats
In an effort to strengthen global capacity to prevent, detect, and control infectious diseases in animals and people, the United States Agency for International Development’s (USAID) Emerging Pandemic Threats (EPT) PREDICT project funded development of regional, national, and local One Health capacities for early disease detection, rapid response, disease control, and risk reduction. From the outset, the EPT approach was inclusive of social science research methods designed to understand the contexts and behaviors of communities living and working at human-animal-environment interfaces considered high-risk for virus emergence. Using qualitative and quantitative approaches, PREDICT behavioral research aimed to identify and assess a range of socio-cultural behaviors that could be influential in zoonotic disease emergence, amplification, and transmission. This broad approach to behavioral risk characterization enabled us to identify and characterize human activities that could be linked to the transmission dynamics of new and emerging viruses. This paper provides a discussion of implementation of a social science approach within a zoonotic surveillance framework. We conducted in-depth ethnographic interviews and focus groups to better understand the individual- and community-level knowledge, attitudes, and practices that potentially put participants at risk for zoonotic disease transmission from the animals they live and work with, across 6 interface domains. When we asked highly-exposed individuals (ie. bushmeat hunters, wildlife or guano farmers) about the risk they perceived in their occupational activities, most did not perceive it to be risky, whether because it was normalized by years (or generations) of doing such an activity, or due to lack of information about potential risks. Integrating the social sciences allows investigations of the specific human activities that are hypothesized to drive disease emergence, amplification, and transmission, in order to better substantiate behavioral disease drivers, along with the social dimensions of infection and transmission dynamics. Understanding these dynamics is critical to achieving health security--the protection from threats to health-- which requires investments in both collective and individual health security. Involving behavioral sciences into zoonotic disease surveillance allowed us to push toward fuller community integration and engagement and toward dialogue and implementation of recommendations for disease prevention and improved health security
Transforming Classroom Instruction into Professional Practice: Bass Fishing or Dodgeball Anyone?
Our challenge as educators is helping prepare students for real world success by creating situations in which students can apply classroom instruction in professional contexts. This presentation focuses on multiple examples of WKU faculty facilitating meaningful, exciting, and marketable experiences for students in an attempt to teach valuable material
The role of imaging in the management of adults with diffuse low grade glioma: A systematic review and evidence-based clinical practice guideline
QUESTION: What is the optimal imaging technique to be used in the diagnosis of a suspected low grade glioma, specifically: which anatomic imaging sequences are critical for most accurately identifying or diagnosing a low grade glioma (LGG) and do non-anatomic imaging methods and/or sequences add to the diagnostic specificity of suspected low grade gliomas?
TARGET POPULATION: These recommendations apply to adults with a newly diagnosed lesion with a suspected or histopathologically proven LGG.
LEVEL II: In patients with a suspected brain tumor, the minimum magnetic resonance imaging (MRI) exam should be an anatomic exam with both T2 weighted and pre- and post-gadolinium contrast enhanced T1 weighted imaging. CRITICAL IMAGING FOR THE IDENTIFICATION AND DIAGNOSIS OF LOW GRADE GLIOMA:
LEVEL II: In patients with a suspected brain tumor, anatomic imaging sequences should include T1 and T2 weighted and Fluid Attenuation Inversion Recovery (FLAIR) MR sequences and will include T1 weighted imaging after the administration of gadolinium based contrast. Computed tomography (CT) can provide additional information regarding calcification or hemorrhage, which may narrow the differential diagnosis. At a minimum, these anatomic sequences can help identify a lesion as well as its location, and potential for surgical intervention. IMPROVEMENT OF DIAGNOSTIC SPECIFICITY WITH THE ADDITION OF NON-ANATOMIC (PHYSIOLOGIC AND ADVANCED IMAGING) TO ANATOMIC IMAGING:
LEVEL II: Class II evidence from multiple studies and a significant number of Class III series support the addition of diffusion and perfusion weighted MR imaging in the assessment of suspected LGGs, for the purposes of discriminating the potential for tumor subtypes and identification of suspicion of higher grade diagnoses.
LEVEL III: Multiple series offer Class III evidence to support the potential for magnetic resonance spectroscopy (MRS) and nuclear medicine methods including positron emission tomography and single-photon emission computed tomography imaging to offer additional diagnostic specificity although these are less well defined and their roles in clinical practice are still being defined.
QUESTION: Which imaging sequences or parameters best predict the biological behavior or prognosis for patients with LGG?
TARGET POPULATION: These recommendations apply to adults with a newly diagnosed lesion with a suspected or histopathologically proven LGG.
RECOMMENDATION: Anatomic and advanced imaging methods and prognostic stratification
LEVEL III: Multiple series suggest a role for anatomic and advanced sequences to suggest prognostic stratification among low grade gliomas. Perfusion weighted imaging, particularly when obtained as a part of diagnostic evaluation (as recommended above) can play a role in consideration of prognosis. Other imaging sequences remain investigational in terms of their role in consideration of tumor prognosis as there is insufficient evidence to support more formal recommendations as to their use at this time.
QUESTION: What is the optimal imaging technique to be used in the follow-up of a suspected (or biopsy proven) LGG?
TARGET POPULATION: This recommendation applies to adults with a newly diagnosed low grade glioma.
LEVEL II: In patients with a diagnosis of LGG, anatomic imaging sequences should include T2/FLAIR MR sequences and T1 weighted imaging before and after the administration of gadolinium based contrast. Serial imaging should be performed to identify new areas of contrast enhancement or significant change in tumor size, which may signify transformation to a higher grade.
LEVEL III: Advanced imaging utility may depend on tumor subtype. Multicenter clinical trials with larger cohorts are needed. For astrocytic tumors, baseline and longitudinal elevations in tumor perfusion as assessed by dynamic susceptibility contrast perfusion MRI are associated with shorter time to tumor progression, but can be difficult to standardize in clinical practice. For oligodendrogliomas and mixed gliomas, MRS may be helpful for identification of progression