1,396 research outputs found
Two-Photon Direct Frequency Comb Spectroscopy of Rubidium
Precision spectroscopy measurements have contributed significantly to our understanding of the fundamental structure of atoms. Here we present an experiment involving a new precision spectroscopic technique using a femtosecond optical frequency comb to excite two-photon transitions in rubidium. A femtosecond optical frequency comb is an ultrashort, pulsed laser with tens of thousands of frequencies, equally spaced in frequency-space. These frequencies can be used to excite atoms to specific transitions. The frequency comb is a versatile instrument that can avoid many of the experimental uncertainties that are associated with other spectroscopic techniques. The specific technique we use is called velocity selective resonance, and it is used to eliminate Doppler broadening in our spectra. In addition, the setup could be cheaply and easily altered to study different atoms or systems. In this experiment, we study this new precision measurement technique of using an optical frequency comb for spectroscopy
Two-Photon Direct Frequency Comb Spectroscopy of Rubidium
Precision spectroscopy measurements have contributed significantly to our understanding of the fundamental structure of atoms. Here we present an experiment involving a new precision spectroscopic technique using a femtosecond optical frequency comb to excite two-photon transitions in rubidium. A femtosecond optical frequency comb is an ultrashort, pulsed laser with tens of thousands of frequencies, equally spaced in frequency-space. These frequencies can be used to excite atoms to specific transitions. The frequency comb is a versatile instrument that can avoid many of the experimental uncertainties that are associated with other spectroscopic techniques. The specific technique we use is called velocity selective resonance, and it is used to eliminate Doppler broadening in our spectra. In addition, the setup could be cheaply and easily altered to study different atoms or systems. In this experiment, we study this new precision measurement technique of using an optical frequency comb for spectroscopy
PW-laser produced MeV proton beams stopped in WDM plasmas (H, He, Ar, N, Xe)
Physical processes involved in the interaction
of ion beams in Warm Dense Matter (WDM)
(i.e. 1-100 eV. 0.01-100 g/cc) is fundamental to
the understanding of condensed matter, solidstate
physics, fusion sciences, and astrophysical
phenomena..
Angiogenesis and Its Role in the Tumour Microenvironment: A Target for Cancer Therapy
The process of angiogenesis refers to the growth of new blood vessels from existing ones. Tumours can produce factors in the micro-environment which act on blood vessels to promote angiogenesis. It is therefore considered to be fundamental in tumour progression and metastatic dissemination. This neovascularization can be regulated by numerous endogenous factors in the tumour micro-environment. As a result, anti-angiogenic therapies have been developed in the hope of targeting this process to reduce tumour growth and progression. However, only a proportion of patients respond to therapy, indicating the presence of treatment resistance in some. In this chapter, we aim to highlight the process of angiogenesis and to review pivotal evidence for the use of anti-angiogenic therapies thus far (alone and in combination with other agents). Finally, we will illustrate recent evidence for the discovery of biomarkers for anti-angiogenic therapies and potential mechanisms of resistance to such agents
IT Outsourcing Success in Healthcare Industry: Build Your Capabilities on Multiple Fronts within the Institutional Framework
In this manuscript we report the findings from an in-depth case study about the factors that determine IT outsourcing success in the healthcare industry. Healthcare organizations in Taiwan are faced with increasing institutional pressures in the forms of hospital accreditation systems and national insurance program requirements. We found that organizations appeared to have adopted similar outsourcing practices under institutional pressures. However, whether or not an organization could successfully implement an outsourcing decision depends on the organization’s IT capabilities, governance capabilities, and capabilities to manage its relationship with the vendor. Research implications of these results are discussed
MCRAGE: Synthetic Healthcare Data for Fairness
In the field of healthcare, electronic health records (EHR) serve as crucial
training data for developing machine learning models for diagnosis, treatment,
and the management of healthcare resources. However, medical datasets are often
imbalanced in terms of sensitive attributes such as race/ethnicity, gender, and
age. Machine learning models trained on class-imbalanced EHR datasets perform
significantly worse in deployment for individuals of the minority classes
compared to samples from majority classes, which may lead to inequitable
healthcare outcomes for minority groups. To address this challenge, we propose
Minority Class Rebalancing through Augmentation by Generative modeling
(MCRAGE), a novel approach to augment imbalanced datasets using samples
generated by a deep generative model. The MCRAGE process involves training a
Conditional Denoising Diffusion Probabilistic Model (CDDPM) capable of
generating high-quality synthetic EHR samples from underrepresented classes. We
use this synthetic data to augment the existing imbalanced dataset, thereby
achieving a more balanced distribution across all classes, which can be used to
train an unbiased machine learning model. We measure the performance of MCRAGE
versus alternative approaches using Accuracy, F1 score and AUROC. We provide
theoretical justification for our method in terms of recent convergence results
for DDPMs with minimal assumptions.Comment: Keywords: synthetic electronic health records, conditional denoising
diffusion probabilistic model, healthcare AI, tabular data, fairness,
synthetic data. This paper is the result of work completed at the 2023 Emory
University Department of Mathematics REU/RET program under the direction of
Project Advisor Dr. Xi Yuanzhe. This work is sponsored by NSF DMS 205101
Cause Event Representations for Happiness and Surprise
PACLIC 23 / City University of Hong Kong / 3-5 December 200
Are Emotions Enumerable or Decomposable? And its Implications for Emotion Processing
PACLIC 23 / City University of Hong Kong / 3-5 December 200
An Integrated Approach to Heterogeneous Data for Information Extraction
PACLIC 23 / City University of Hong Kong / 3-5 December 200
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Health, environmental, and animal rights motives for vegetarian eating.
Health, the environment, and animal rights represent the three main reasons people cite for vegetarian diet in Western societies. However, it has not been shown that these motives can be distinguished empirically, and little is known about what kind of people are likely to be compelled by these different motives. This study had three goals. First, we aimed to use construct validation to test whether develop health, environmental, and animal rights motives for a vegetarian diet could be distinguished. Second, we evaluated whether these motivations were associated with different demographic, behavioral, and personality profiles in three diverse samples. Third, we examined whether peoples' motivations were related to responses to vegetarian advocacy materials. We created the Vegetarian Eating Motives Inventory, a 15-item measure whose structure was invariant across three samples (N = 1006, 1004, 5478) and two languages (English and Dutch). Using this measure, we found that health was the most common motive for non-vegetarians to consider vegetarian diets and it had the broadest array of correlates, which primarily involved communal and agentic values. Correlates of environmental and animal rights motives were limited, but these motives were strong and specific predictors of advocacy materials in a fourth sample (N = 739). These results provide researchers with a useful tool for identifying vegetarian motives among both vegetarian and non-vegetarian respondents, offer useful insights into the nomological net of vegetarian motivations, and provide advocates with guidance about how to best target campaigns promoting a vegetarian diet
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