Natural Horn Performance in the 19th Century

The natural horn developed from an instrument of the hunt into an orchestral instrument in the 18th century. The switch from outdoors to concert hall was helped along by the development of hand horn technique, which allowed for all chromatic notes to be played on the instrument. This led to an extremely fruitful time of virtuoso hand horn soloists through outEurope. The instrument evoked a very particular aesthetic: light, nimble, virtuosic, “natural”, voice-like, etc. Then when the invention of the valves was applied to the natural horn it was met with a fair amount of resistance. The natural horn persisted in much composition and playing well after the invention of the valve horn. This happened due to the influence of tradition, performers, and a particular naturalist aesthetic that persisted from the classical period into the romantic. This paper proves this thesis by using musical examples from all over Europethat employed or could be played on natural horn even though they were composed after the advent of the valve horn. I also use first hand quotes from music critics of the 19th century who spoke of the varying aesthetics of the natural horn and valve horn, in addition to letters and other writings. Between sources from the 19th century and scholarly analyses from the present there is a strong basis to believe in the importance of performers and particular aesthetics in the matter of these two instruments. This topic is still important today for a variety of reasons, for one, to be able to have well informed historical period performances on natural instruments. It is also important in understanding writing for the horn to this day, and what makes certain things idiomatic for even the valve horn. It’s also key for more informed decisions on phrasing and dynamics based on what the composer would have wanted on a natural instrument, which can greatly help our musicality even on valve horns today. On a larger scale, this paper shows the interaction between performer and composer, how we affect each other, and how societal and traditional aesthetic ideals can inform our work as musicians

Donor-specific Cell-based Assays in Studying Sensitivity to Low-dose Radiation: A Population-based Perspective

Currently, a linear no-threshold model is used to estimate health risks associated with exposure to low-dose radiation, a prevalent exposure in the general population, because the direct estimation from epidemiological studies suffers from uncertainty. This model has been criticized based on unique biology of low-dose radiation. Whether the departure from linearity is toward increased or decreased risk is intensely debated. We present an approach based on individual radiosensitivity testing and discuss how individual radiosensitivity can be assessed with the goal to develop a quantifiable measure of cellular response that can be conducted via high-throughput population testing

Terahertz Spectroscopy System of Gas Mixtures Based on a Solid State Superconducting Source and a Terahertz Receiver

Abstract: The application of a Josephson generator of the terahertz range based on a long superconductor–insulator–superconductor tunnel junction matched with a transmitting antenna and emitting a signal into open space is demonstrated for gas spectroscopy. The generator is used as an active source, the signal of which is absorbed by a sample of a gas mixture in a cell with a length of 60 cm and then recorded by a spectrometer based on a superconductor–insulator–superconductor receiver with a spectral resolution better than 100 kHz. In the experiment, the absorption lines of ammonia and water in the terahertz range were recorded, and the dependence of the spectral characteristics of the absorption lines on the pressure of the gas mixture in a wide range (from 0.005 to 10 mbar) was demonstrated

Unusual linewidth dependence of coherent THz emission measured from intrinsic Josephson junction stacks in the hot-spot regime

We report on measurements of the linewidth {\Delta}f of THz radiation emitted from intrinsic Josephson junction stacks, using a Nb/AlN/NbN integrated receiver for detection. Previous resolution limited measurements indicated that {\Delta}f may be below 1 GHz - much smaller than expected from a purely cavity-induced synchronization. While at low bias we found {\Delta}f to be not smaller than ? 500 MHz, at high bias, where a hotspot coexists with regions which are still superconducting, {\Delta}f turned out to be as narrow as 23 MHz. We attribute this to the hotspot acting as a synchronizing element. {\Delta}f decreases with increasing bath temperature, a behavior reminiscent of motional narrowing in NMR or ESR, but hard to explain in standard electrodynamic models of Josephson junctions.Comment: 4 figures, 5 page

An Antenna with a Feeder for a Superconducting Terahertz Josephson Oscillator with Phase Locking

A principal layout of a Josephson terahertz radiation oscillator integrated with a transmitting antenna-lens system and a harmonic mixer (HM) for phase locking of radiation has been proposed and was successfully implemented. Two antenna-feeder systems designed for the central frequencies of 0.3 and 0.6 THz and located on the same chip with the oscillator are numerically simulated and fabricated. A microstrip transmission line between the oscillator and the antenna is used as the feeder. A study was carried out on matching the oscillator power and HM for two designs; the frequency range of pumping HM was 0.25-0.45 and 0.5-0.68 THz for the designs at 0.3 and 0.6 THz, respectively. Good agreement was obtained between experimental results and numerical simulations. A study of the spectral characteristics of the radiation of the oscillator into the external space for the 0.6 THz design using a superconducting integrated spectrometer was carried out. The linewidth of an emission line in free-running regime was of the order of several megahertz; in the phase locking regime down to tens of kilohertz with a signal-to-noise ratio of more than 20 dB was obtained

Terahertz Spectroscopy of Gas Absorption Using the Superconducting Flux-Flow Oscillator as an Active Source and the Superconducting Integrated Receiver

We report on the first implementation of a terahertz (THz) source based on a Josephson flux-flow oscillator (FFO) that radiates to open space. The excellent performance of this source and its maturity for practical applications has been demonstrated by the spectroscopy of gas absorption. To study the radiated power, we used a bolometric detection method and additionally calibrated the power by means of pumping the superconductor–insulator–superconductor (SIS) junction, integrated on a single chip with the FFO. For calibration, we developed a program using the SIS-detected power calculations in accordance with the Tien and Gordon model. The power emitted to open space is estimated to be from fractions of µW to several µW in the wide region from 0.25 THz up to 0.75 THz for different designs, with a maximum power of 3.3 µW at 0.34 THz. Next, we used a gas cell and a heterodyne superconducting integrated receiver to trace the absorption lines of water and ammonia with a spectral resolution better than 100 kHz. Our experiment for gas absorption is the first demonstration of the applicability of the FFO as an external active source for different tasks, such as THz spectroscopy, near-field THz imaging and microscopy

A superconducting flux-flow oscillator of terahertz range

We have elaborated, fabricated and tested a THz source radiating to open space based on the superconducting flux-flow oscillator (FFO). In this concept, the oscillator is integrated with the transmitting lens antenna based on a slot structure in Nb film with a thickness of ∼200 nm located on the same chip. The slot planar antenna is matched to the oscillator (by input) and to the semielliptical Si lens with a diameter of 10 mm (by output) providing a narrow output beam of THz emission. A harmonic mixer based on the superconductor-insulator-superconductor junction embedded in the "FFO and antenna" integrated structure has been used for the phase locking of the oscillator. Several designs of antenna coupled with the oscillator by microstrip lines have been numerically simulated, and the batches of experimental samples based on Nb-AlN-NbN superconducting trilayers with Rn •A ∼ 20 Ω•μm2 (jc ∼ 10 kA/cm2) have been fabricated and tested. Two different setups were used for experimental study: A THz spectrometer based on the SIS receiver with a high spectral resolution (better than 0.1 MHz) and a Si bolometer. The overall operating range of 250 to 700 GHz is covered by all the developed designs

A Human BRCA2 Complex Containing a Structural DNA Binding Component Influences Cell Cycle Progression

AbstractGermline mutations of the human BRCA2 gene confer susceptibility to breast cancer. Although the function of the BRCA2 protein remains to be determined, murine cells homozygous for BRCA2 inactivation display chromosomal aberrations. We have isolated a 2 MDa BRCA2-containing complex and identified a structural DNA binding component, designated as BR CA2-A ssociated F actor 35 (BRAF35). BRAF35 contains a nonspecific DNA binding HMG domain and a kinesin-like coiled coil domain. Similar to BRCA2, BRAF35 mRNA expression levels in mouse embryos are highest in proliferating tissues with high mitotic index. Strikingly, nuclear staining revealed a close association of BRAF35/BRCA2 complex with condensed chromatin coincident with histone H3 phosphorylation. Importantly, antibody microinjection experiments suggest a role for BRCA2/BRAF35 complex in modulation of cell cycle progression