The signature of a double quantum-dot structure in the I-V characteristics of a complex system

We demonstrate that by carefully analyzing the temperature dependent characteristics of the I-V measurements for a given complex system it is possible to determine whether it is composed of a single, double or multiple quantum-dot structure. Our approach is based on the orthodox theory for a double-dot case and is capable of simulating I-V characteristics of systems with any resistance and capacitance values and for temperatures corresponding to thermal energies larger than the dot level spacing. We compare I-V characteristics of single-dot and double-dot systems and show that for a given measured I-V curve considering the possibility of a second dot is equivalent to decreasing the fit temperature. Thus, our method allows one to gain information about the structure of an experimental system based on an I-V measurement.Comment: 12 pages 7 figure

Coexistence of Coulomb blockade and zero bias anomaly in a strongly coupled quantum dot

The current-voltage characteristics through a metallic quantum dot which is well coupled to a metallic lead are measured. It is shown that the I-V curves are composed of two contributions. One is a suppression of the tunneling conductivity at the Fermi level and the second is an oscillating feature which shifts with gate voltage. The results indicate that Zero-Bias-Anomaly and Coulomb Blockade phenomena coexist in an asymmetric strongly coupled quantum dot.Comment: 4 pages, 4 figure

Zero bias anomaly in a two dimensional granular insulator

We compare tunneling density of states (TDOS) into two ultrathin Ag films, one uniform and one granular, for different degrees of disorder. The uniform film shows a crossover from Altshuler-Aronov (AA) zero bias anomaly to Efros Shklovskii (ES) like Coulomb gap as the disorder is increased. The granular film, on the other hand, exhibits AA behavior even deeply in the insulating regime. We analyze the data and find that granularity introduces a new regime for the TDOS. While the conductivity is dominated by hopping between clusters of grains and is thus insulating, the TDOS probes the properties of an individual cluster which is "metallic".Comment: 4 pages, 4 figure

Realtime Photoacoustic Microscopy of Murine Cardiovascular Dynamics

Non-invasive visualization of cardiovascular dynamics in small animals is challenging due to their rapid heart-rates. We present a realtime photoacoustic imaging system consisting of a 30-MHz ultrasound array transducer, receive electronics, a high-repetition-rate laser, and a multicore-computer, and demonstrate its ability to image optically-absorbing structures of the beating hearts of young athymic nude mice at rates of ~50 frames per second with 100 µm×25 µm spatial resolution. To our knowledge this is the first report of realtime photoacoustic imaging of physiological dynamics

Comparison of systolic blood pressure measurements by auscultation and visual manometer needle jump

International Journal of Exercise Science 12(2): 214-220, 2019. Purpose: This study was designed to investigate differences in systolic blood pressure measurements as obtained through auscultation and observation of the visual jump on the manometer. Methods: Men (n = 21; 26.9 ± 7.4 yrs) and women (n = 22; 29.3 ± 13.9 yrs) volunteered to have resting systolic blood pressure (SBP) assessments. During the same cardiac inflation-deflation cycle of traditional sphygmomanometry, the initial visual jump of the manometer needle and first Korotkoff sound heard were recorded. Duplicate assessments were made in each arm with 30 sec between intra-arm trials. Results: Paired t-test results indicated there were no within-method differences between arms for visual jump (R: 132.1 ± 11.3; L: 131.8 ± 10.5 mmHg) or auscultation (R: 116.8 ± 9.0; L: 113.5 ± 8.8 mmHg). There were methodological differences within arm with visual jump being the higher of the two (right: t(42) = -12.69; left: t(42) = -11.37; p \u3c .001). Conclusion: If visual jump determination of SBP cannot be avoided, re-assessment using a more traditional method (i.e. auscultation) is recommended

Primary thermometry in the intermediate Coulomb blockade regime

We investigate Coulomb blockade thermometers (CBT) in an intermediate temperature regime, where measurements with enhanced accuracy are possible due to the increased magnitude of the differential conductance dip. Previous theoretical results show that corrections to the half width and to the depth of the measured conductance dip of a sensor are needed, when leaving the regime of weak Coulomb blockade towards lower temperatures. In the present work, we demonstrate experimentally that the temperature range of a CBT sensor can be extended by employing these corrections without compromising the primary nature or the accuracy of the thermometer.Comment: 8 pages, 4 figure

Baseline corticosterone does not reflect iridescent plumage traits in female tree swallows

The production of high quality secondary sexual traits can be constrained by trade-offs in the allocation of energy and nutrients with other metabolic activities, and is mediated by physiological processes. In birds, the factors influencing male plumage quality have been well studied; however, factors affecting female plumage quality are poorly understood. Furthermore, it remains uncertain which physiological traits mediate the relationship between body condition and ornaments. In this three-year study of after-second-year female tree swallows (Tachycineta bicolor), we investigated (1) the relationship between baseline corticosterone near the end of the brood-rearing period (CORTBR) and feather colour characteristics (hue, saturation, brightness) the following year, and (2) the relationship between baseline corticosterone measured during incubation (CORTI) and brood rearing (CORTBR), and feather colour in the same year. To control for reproductive effort, we included reproductive parameters as covariates in all analyses. In this first study between CORT and the plumage colour characteristics of a species bearing iridescent feathers, we did not find any relationship between CORTBR and the colour of subsequently-produced feathers, nor did we find any relationship between CORT and the colour of feathers displayed during that breeding season. If CORT levels at the end of breeding carry over to influence the immediately subsequent moult period as we expect, our results generally indicate that structural plumage quality may not be as sensitive to circulating CORT levels compared to carotenoid-based colouration. Future studies, particularly those employing experimental manipulations of CORT during moult in species with iridescent traits, are necessary to fully determine the role glucocorticoids play in mediating the quality of secondary sexual characteristics

Realtime Photoacoustic Microscopy of Murine Cardiovascular Dynamics

Non-invasive visualization of cardiovascular dynamics in small animals is challenging due to their rapid heart-rates. We present a realtime photoacoustic imaging system consisting of a 30-MHz ultrasound array transducer, receive electronics, a high-repetition-rate laser, and a multicore-computer, and demonstrate its ability to image optically-absorbing structures of the beating hearts of young athymic nude mice at rates of ~50 frames per second with 100 µm×25 µm spatial resolution. To our knowledge this is the first report of realtime photoacoustic imaging of physiological dynamics