1,704 research outputs found
Bosonic behavior of entangled fermions
Two bound, entangled fermions form a composite boson, which can be treated as
an elementary boson as long as the Pauli principle does not affect the behavior
of many such composite bosons. The departure of ideal bosonic behavior is
quantified by the normalization ratio of multi-composite-boson states. We
derive the two-fermion-states that extremize the normalization ratio for a
fixed single-fermion purity P, and establish general tight bounds for this
indicator. For very small purities, P<1/N^2, the upper and lower bounds
converge, which allows to quantify accurately the departure from perfectly
bosonic behavior, for any state of many composite bosons.Comment: 9 pages, 5 figures, accepted by PR
Experimental performance of compact UWB antenna for breast cancer screening
This paper presents experimental performances of the algorithm used for detection of malignant tissue in breast. The algorithm uses ultra-short pulse radar (USPR) technique along with confocal microwave imaging (CMI) algorithm based on synthetic aperture radar (SAR) to detect tumor cells or tissue. A compact Vivaldi antenna having ultra-wideband (UWB) performance with bandwidth 3 GHz to 8 GHz is used as transceiver and an impulse with no distortion is used as an excitation signal in our experiment. We used various synthetic breast phantom and metallic or high-k dielectric balls as tumor. The skin subtraction method using Teflon cover seems to be promising for this experiment
Association between the Health Belief Model, Exercise, and Nutrition Behaviors during the COVID-19 Pandemic
Introduction: The COVID-19 pandemic has affected our nation’s health further than the infection it causes. Physical activity levels and dietary intake have suffered while individuals grapple with the changes in behavior to reduce viral transmission. With unique nuances regarding the access to physical activity and nutrition during the pandemic, the constructs of Health Belief Model (HBM) may present themselves differently in nutrition and exercise behaviors compared to precautions implemented to reduce viral transmission studied in previous research. The purpose of this study was to investigate the extent of exercise and nutritional behavior change during the COVID-19 pandemic and explain the reason for and extent of this change using HBM constructs (perceived susceptibility, severity, benefit of action, and barriers to action). Methods: This study used a cross-sectional design to collect 206 surveys. This survey collected information on self-reported exercise and nutrition changes during the pandemic and self-reported levels of the HBM constructs. Results: Findings showed individuals with medium or high exercise behavior change had greater odds of increased HBM score than individuals with little to no exercise behavior change (OR = 1.117, 95% CI: 1.020–1.223, SE: 0.0464, p = 0.0175). There was no association between nutritional behavior change and HBM score (OR = 1.011, 95% CI: 0.895–1.142, p = 08646). Conclusion: Individuals who reported a more drastic change in either exercise had greater odds of increased feelings of perceived susceptibility and severity related to COVID-19 and decreased perceived benefits and increased barriers to exercise. This relationship was not found regarding nutrition behavior change. These results encourage public health practitioners to understand how an individual’s perceived feelings about a threat may affect exercise and nutritional behaviors
Universal Magnetic-Field-Driven Metal-Insulator-Metal Transformations in Graphite and Bismuth
Applied magnetic field induces metal - insulator and re-entrant
insulator-metal transitions in both graphite and rhombohedral bismuth. The
corresponding transition boundaries plotted on the magnetic field - temperature
(B - T) plane nearly coincide for these semimetals and can be best described by
power laws T ~ (B - B_c)^k, where B_c is a critical field at T = 0 and k = 0.45
+/- 0.05. We show that insulator-metal-insulator (I-M-I) transformations take
place in the Landau level quantization regime and illustrate how the IMT in
quasi-3D graphite transforms into a cascade of I-M-I transitions, related to
the quantum Hall effect in quasi-2D graphite samples. We discuss the possible
coupling of superconducting and excitonic correlations with the observed
phenomena, as well as the signatures of quantum phase transitions associated
with the M-I and I-M transformations.Comment: 23 pages including 14 figure
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