We perform tunneling measurements on indium antimonide nanowire-superconductor hybrid devices fabricated for the studies of Majorana bound states. At finite magnetic field, resonances that strongly ...resemble Majorana bound states, including zero-bias pinning, become common to the point of ubiquity. Since Majorana bound states are predicted in only a limited parameter range in nanowire devices, we seek an alternative explanation for the observed zero-bias peaks. With the help of a self-consistent Poission-Schrödinger multiband model developed in parallel, we identify several families of trivial subgap states that overlap and interact, giving rise to a crowded spectrum near zero energy and zero-bias conductance peaks in experiments. These findings advance the search for Majorana bound states through improved understanding of broader phenomena found in superconductor-semiconductor systems.
Improving materials used to make qubits is crucial to further progress in quantum information processing. Of particular interest are semiconductor-superconductor heterostructures that are expected to ...form the basis of topological quantum computing. We grew semiconductor indium antimonide nanowires that were coated with shells of tin of uniform thickness. No interdiffusion was observed at the interface between Sn and InSb. Tunnel junctions were prepared by in situ shadowing. Despite the lack of lattice matching between Sn and InSb, a 15-nanometer-thick shell of tin was found to induce a hard superconducting gap, with superconductivity persisting in magnetic field up to 4 teslas. A small island of Sn-InSb exhibits the two-electron charging effect. These findings suggest a less restrictive approach to fabricating superconducting and topological quantum circuits.
•Sustainable application is a way to reduce harmful influence to the living environment.•The establishment to estimate the canopy leaf area in crop protection.•Sensing system for digital canopy ...characterization.
This paper compares LIDAR and manual measurements of leaf area in orchards. The LIDAR measurements were performed in real orchard conditions. LIDAR data were used to count the number of points and to measure the canopy volume of individual volume elements. Manual measurements included defoliation, counting and leaf area measurements. Both types of measurements were performed in 8 volume elements for 20 apple trees of three different ages and varieties (‘Golden delicious’, ‘Jonagold’ and ‘Gala’). Using regression analysis, we estimated the relation between number of points in the cloud, canopy volume (both LIDAR measurements) and the leaf area (manual measurement). The maximum value of the correlation coefficient was 0.87816, when established from the relation between the number of points in the cloud and the canopy leaf area. The maximum value of the correlation coefficient was 0.80167, when established between the volume of tree canopy volume element and the leaf area.
We present a comprehensive study of the performance of GaN single-nanowire photodetectors containing an axial p–n junction. The electrical contact to the p region of the diode is made by including a ...p+/n+ tunnel junction as cap structure, which allows the use of the same metal scheme to contact both ends of the nanowire. Single-nanowire devices present the rectifying current–voltage characteristic of a p–n diode but their photovoltaic response to ultraviolet radiation scales sublinearly with the incident optical power. This behavior is attributed to the dominant role of surface states. Nevertheless, when the junction is reverse biased, the role of the surface becomes negligible in comparison to the drift of photogenerated carriers in the depletion region. Therefore, the responsivity increases by about 3 orders of magnitude and the photocurrent scales linearly with the excitation. These reverse-biased nanowires display decay times in the range of ∼10 μs, limited by the resistor-capacitor time constant of the setup. Their ultraviolet/visible contrast of several orders of magnitude is suitable for applications requiring high spectral selectivity. When the junction is forward biased, the device behaves as a GaN photoconductor with an increase of the responsivity at the price of a degradation of the time response. The presence of leakage current in some of the wires can be modeled as a shunt resistance which reacts to the radiation as a photoconductor and can dominate the response of the wire even under reverse bias.
We perform transport measurements on double quantum dots defined in Ge/Si core/shell nanowires and focus on Pauli spin blockade in the regime where tens of holes occupy each dot. We identify spin ...blockade through the magnetic field dependence of the leakage current. We find both a dip and a peak in the leakage current at zero field. We analyze this behavior in terms of quantum dot parameters such as coupling to the leads, interdot tunnel coupling, as well as spin-orbit interaction. We estimate a lower bound on the spin-orbit parameter corresponding to an upper bound of lso=500 nm for the Rashba spin-orbit length. We also extract effective Landé g factors up to 8.0 from field-dependent spin blockade measurements.
We study transport mediated by Andreev bound states formed in InSb nanowire quantum dots. Two kinds of superconducting source and drain contacts are used: epitaxial Al/InSb devices exhibit a doubling ...of tunneling resonances, while, in NbTiN/InSb devices, Andreev spectra of the dot appear to be replicated multiple times at increasing source-drain bias voltages. In both devices, a mirage of a crowded spectrum is created. To describe the observations a model is developed that combines the effects of a soft induced gap and of additional Andreev bound states both in the quantum dot and in the finite regions of the nanowire adjacent to the quantum dot. Understanding of Andreev spectroscopy is important for the correct interpretation of Majorana experiments done on the same structures.
Abstract
Pancreatic cancer is the fourth leading cause of cancer deaths in the United States. Perfluorooctanoic acid (PFOA), a persistent environmental pollutant, has been shown to induce pancreatic ...acinar cell tumors in rats. Human epidemiologic studies have linked PFOA exposure to adverse chronic health effects including several types of cancer. Previously, we demonstrated that PFOA induces oxidative stress and focal ductal hyperplasia in the mouse pancreas. Here, we evaluated whether PFOA promotes pancreatic cancer using the LSL-KRasG12D;Pdx-1 Cre (KC) mouse model of pancreatic cancer. KC mice were exposed to 5 ppm PFOA in drinking water starting at 8 weeks of age and analyzed at 6 and 9 months of age. At the 6-month time point, PFOA exposure increased pancreatic intraepithelial neoplasia (PanIN) area by 58%, accompanied by a 2-fold increase in lesion number. Although PanIN area increased at 9 months, relative to 6 months, no treatment effect was observed. Collagen deposition was enhanced by PFOA at both the 6- and 9-month time points. PFOA also induced oxidative stress in the pancreas evidenced by elevated antioxidant activity of superoxide dismutase (Sod), catalase and thioredoxin reductase, and a ~3-fold increase in Sod1 mRNA and protein levels at 6 months. Although antioxidant activity was not enhanced by PFOA exposure at the 9-month time point, increased pancreatic oxidative damage was observed. Collectively, these results show that PFOA elicited temporal increases in PanIN lesion area and desmoplasia concomitant with the induction of oxidative stress, demonstrating that it functions to promote pancreatic cancer progression.
We demonstrate that PFOA exposure elicits temporal increases in PanIN lesion area and desmoplasia concomitant with the induction of oxidative stress in the LSL-KRasG12D;Pdx-1Cre mouse model of pancreatic cancer, demonstrating that PFOA exposure acts at the promotion stage of carcinogenesis.
Graphical Abstract
Graphical Abstract
Estimating the live weight of bulls by measurement of body dimensions with thermography and thermal image analysis was studied during progeny testing of the Simmental breed. The experimental group of ...bulls was measured seven times every 60 days from housing at the average age of 139 days (181
kg) till slaughtering (449 days, 594
kg). Each bull was weighed, manually measured and captured by the thermal camera. This device, together with the image analysis algorithm, proved to be a successful tool for estimating the wither height (Wh) and hip height (Hh) during all seven age classes. The SEE values for Wh decreased significantly during all weighing from 5.49
cm at day 139 to 1.11
cm at day 449 and from 4.99 to 1.76
cm for Hh, respectively. Two linear models for estimating current body weight at different ages were also developed on the basis of the long-term herd data of the Wh (BW1) and Hh (BW2) measurements. A statistically significant relationship (
P
<
0.05) was found for all seven age classes, whereby the
R
adj
2
was varying with the age from 0.11 to 0.66 (BW1) and from 0.15 to 0.74 (BW2). Since the SEE values increased a little from 24.96
kg at day 139 to 33.59
kg at last weighing for the BW1 and from 21.76 to 32.69
kg for the BW2, both models expressed high accuracies. Therefore the thermal camera shows to be a useful tool in estimating live BW, which is of significant importance in reducing stress during progeny testing and beef production.
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