1,036 research outputs found
Tuning a racetrack ring resonator by an integrated dielectric MEMS cantilever
The principle, fabrication and characterization of a dielectric MEMS cantilever located a few 100 nm above a racetrack ring resonator are presented. After fabrication of the resonators on silicon-on-insulator (SOI) wafers in a foundry process, the cantilevers were integrated by surface micromachining techniques. Off-state deflections of the cantilevers have been optimized to appropriately position them near the evanescent field of the resonator. Using electrostatic actuation, moving the cantilevers into this evanescent field, the propagation properties of the ring waveguide are modulated. We demonstrate 122 pm tuning of the resonance wavelength of the optical ring resonator (in the optical C-band) without change of the optical quality factor, on application of 9 V to a 40 ”m long cantilever. This compact integrated device can be used for tuning/switching a specific wavelength, with very little energy for operation and negligible cross talk with surrounding device
Rationality as the Rule of Reason
The demands of rationality are linked both to our subjective normative perspective (given that rationality is a person-level concept) and to objective reasons or favoring relations (given that rationality is non-contingently authoritative for us). In this paper, I propose a new way of reconciling the tension between these two aspects: roughly, what rationality requires of us is having the attitudes that correspond to our take on reasons in the light of our evidence, but only if it is competent. I show how this view can account for structural rationality on the assumption that intentions and beliefs as such involve competent perceptions of downstream reasons, and explore various implications of the account
The connection between migration and regional structure in Finland around 1990 - a GIS viewpoint
The connection between migration and regional structure in Finland in the early 19905 is discussed on the basis of Geographic Irformation Systems (GIS) data from Statistics Finland, compiled for map coordinate grid cells of 1 x 1 km. The results indicate that data of this kind enable a more detailed typology to be drawn up for migration. At the regional level, this allows the defining of places of "passing through '' which gain population from other local government districts but lose population through migration within their own district. The connection between migration and regional structure is manifested in the fact that flows both between and within local government districts mainly involve the more urbanised population centres and areas with: high levels of unemployment
Magnetic resonance scanning and image segmentation procedure at 3 T for volumetry of human hippocampal subfields
Measurements of shot noise in single walled carbon nanotubes
We have measured shot noise in single walled carbon nanotubes (SWNT) at 4.2K over frequencies f = 600 â 850 MHz. Here we report results obtained on shot noise without DC bias by applying an AC modulation at Ï0 and recording the noise variation at 2Ï0: the Fano factor is obtained by extrapolating down to zero excitation amplitude. We also discuss the applicability of this method in samples which have strongly nonâlinear IV characteristics like carbon nanotubes. The obtained results are compared with regular differential noise measurements where both DC and AC bias are employed.Peer reviewe
Effect of quantum noise on Coulomb blockade in normal tunnel junctions at high voltages
We have investigated asymptotic behavior of normal tunnel junctions at
voltages where even the best ohmic environments start to look like RC
transmission lines. In the experiments, this is manifested by an exceedingly
slow approach to the linear behavior above the Coulomb gap. As expected on the
basis of the quantum theory taking into account interaction with the
environmental modes, better fits are obtained using 1/sqrt{V}- than 1/V-
dependence for the asymptote. These results agree with the horizon picture if
the frequency-dependent phase velocity is employed instead of the speed of
light in order to determine the extent of the surroundings seen by the
junction.Comment: 9 pages, 4 figures, submitted to Phys. Rev.
Systematic Analysis of Long Non-Coding RNA Genes in Nonalcoholic Fatty Liver Disease
The largest solid organ in humans, the liver, performs a variety of functions to sustain life. When damaged, cells in the liver can regenerate themselves to maintain normal liver physiology. However, some damage is beyond repair, which necessitates liver transplantation. Increasing rates of obesity, Western diets (i.e., rich in processed carbohydrates and saturated fats), and cardiometabolic diseases are interlinked to liver diseases, including non-alcoholic fatty liver disease (NAFLD), which is a collective term to describe the excess accumulation of fat in the liver of people who drink little to no alcohol. Alarmingly, the prevalence of NAFLD extends to 25% of the world population, which calls for the urgent need to understand the disease mechanism of NAFLD. Here, we performed secondary analyses of published RNA sequencing (RNA-seq) data of NAFLD patients compared to healthy and obese individuals to identify long non-coding RNAs (lncRNAs) that may underly the disease mechanism of NAFLD. Similar to protein-coding genes, many lncRNAs are dysregulated in NAFLD patients compared to healthy and obese individuals, suggesting that understanding the functions of dysregulated lncRNAs may shed light on the pathology of NAFLD. To demonstrate the functional importance of lncRNAs in the liver, loss-of-function experiments were performed for one NAFLD-related lncRNA, LINC01639, which showed that it is involved in the regulation of genes related to apoptosis, TNF/TGF, cytokine signaling, and growth factors as well as genes upregulated in NAFLD. Since there is no lncRNA database focused on the liver, especially NAFLD, we built a web database, LiverDB, to further facilitate functional and mechanistic studies of hepatic lncRNAs
Quantum Conductance of the Single Electron Transistor
The quantum conductance of the single-electron tunneling (SET) transistor is
investigated in this paper by the functional integral approach. The formalism
is valid for arbitrary tunnel resistance of the junctions forming the SET
transistor at any temperature. The path integrals are evaluated by the
semiclassical method to yield an explicit non-perturbation form of the quantum
conductance of the SET transistor. An anomaly of the quantum conductance is
found if the tunnel resistances are much smaller than the quantum resistance.
The dependence of the conductance on the gate voltage is also discussed.Comment: 4 pages including some mathe details of cond-mat/990806
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