A microrod-resonator Brillouin laser with 240 Hz absolute linewidth

We demonstrate an ultralow-noise microrod-resonator based laser that oscillates on the gain supplied by the stimulated Brillouin scattering optical nonlinearity. Microresonator Brillouin lasers are known to offer an outstanding frequency noise floor, which is limited by fundamental thermal fluctuations. Here, we show experimental evidence that thermal effects also dominate the close-to-carrier frequency fluctuations. The 6-mm diameter microrod resonator used in our experiments has a large optical mode area of ~100 {\mu}m$^2$, and hence its 10 ms thermal time constant filters the close-to-carrier optical frequency noise. The result is an absolute laser linewidth of 240 Hz with a corresponding white-frequency noise floor of 0.1 Hz$^2$/Hz. We explain the steady-state performance of this laser by measurements of its operation state and of its mode detuning and lineshape. Our results highlight a mechanism for noise that is common to many microresonator devices due to the inherent coupling between intracavity power and mode frequency. We demonstrate the ability to reduce this noise through a feedback loop that stabilizes the intracavity power.Comment: 11 pages, 5 figure

Archive Management of NASA Earth Observation Data to Support Cloud Analysis

NASA collects, processes and distributes petabytes of Earth Observation (EO) data from satellites, aircraft, in situ instruments and model output, with an order of magnitude increase expected by 2024. Cloud-based web object storage (WOS) of these data can simplify the execution of such an increase. More importantly, it can also facilitate user analysis of those volumes by making the data available to the massively parallel computing power in the cloud. However, storing EO data in cloud WOS has a ripple effect throughout the NASA archive system with unexpected challenges and opportunities. One challenge is modifying data servicing software (such as Web Coverage Service servers) to access and subset data that are no longer on a directly accessible file system, but rather in cloud WOS. Opportunities include refactoring of the archive software to a cloud-native architecture; virtualizing data products by computing on demand; and reorganizing data to be more analysis-friendly

Hanford Site Technical Baseline Data Dictionary

The purpose of this Data Dictionary is to provide information concerning the structure and information contained in the Hanford Site Technical Baseline Database (HSTD)

A microrod optical-frequency reference in the ambient environment

We present an ultrahigh-$Q$, solid-silica microrod resonator operated under ambient conditions that supports laser-fractional-frequency stabilization to the thermal-noise limit of $3 \times 10^{-13}$ and a linewidth of 62 Hz. We characterize the technical-noise mechanisms for laser stabilization, which contribute significantly less than thermal noise. With fiber photonics, we generate optical and microwave reference signals provided by the microrod modes and the free-spectral range, respectively. Our results suggest the future physical considerations for a miniature, low noise, and robust optical-frequency source.Comment: 5 pages, 4 figure

Morphological and molecular evidence supports specific recognition of the recently extinct Bettongia anhydra (Marsupialia: Macropodidae)

In 1933, geologist and explorer Michael Terry collected the skull of a small macropodid captured by members of his party near Lake Mackay, western Northern Territory. In 1957, this skull was described as the sole exemplar of a distinct subspecies, Bettongia penicillata anhydra, but was later synonymized with B. lesueur and thereafter all but forgotten. We use a combination of craniodental morphology and ancient mitochondrial DNA to confirm that the Lake Mackay specimen is taxonomically distinct from all other species of Bettongia and recognize an additional specimen from a Western Australian Holocene fossil accumulation. B. anhydra is morphologically and genetically most similar to B. lesueur but differs in premolar shape, rostrum length, dentary proportions, and molar size gradient. In addition, it has a substantial mitochondrial cytochrome b pairwise distance of 9.6–12% relative to all other bettongs. The elevation of this recently extinct bettong to species status indicates that Australia’s mammal extinction record over the past 2 centuries is even worse than currently accepted. Like other bettongs, B. anhydra probably excavated much of its food and may have performed valuable ecological services that improved soil structure and water infiltration and retention, as well as playing an important role in the dispersal of seeds and mycorrhizal fungal spores. All extant species of Bettongia have experienced extensive range contractions since European colonization and some now persist only on island refugia. The near total loss of these ecosystem engineers from the Australian landscape has far-reaching ecological implications

[\u3csup\u3e3\u3c/sup\u3eH]‑Raffinose, a Novel Radioactive Label for Determining Organ Sites of Catabolism of Proteins in the Circulation

The primary tissue sites of catabolism of plasma proteins with long circulating half-lives are unknown. It has been difficult to identify these sites because plasma proteins are delivered to tissues at relatively slow rates but are rapidly degraded intracellularly within lysosomes. Therefore, a tracer attached to protein is lost from the site of uptake before an amount sufficient for quantitation can accumulate. We hypothesized that sucrose (Glupal-2 /3Fruf) would be a useful label to circumvent this difficulty because of the stability of sucrose in lysosomes; and thus, sucrose should remain in tissue long after the protein to which it was attached had been degraded to products released from the lysosome. [G-3HJRaffinose (RAF, Galpal- Glupcwl- 2flFruf) was selected as the vehicle for attaching sucrose to protein. [31XjRAF was converted to the C-6 aldehydogalactose form with galactose oxidase and then covalently coupled to protein by reductive amination using NaBH3CN. [‘H]RAF was coupled first to two relatively long lived plasma proteins, bovine serum albumin and fetuin. The half-lives of these proteins in the rat circulation (&,* = -24 h) was unchanged, suggesting that RAF did not alter the normal mechanisms of protein clearance. When attached to short lived proteins with known sites of catabolism, such as asialofetuin, RNase B, and heatdenatured albumin, neither the tissue nor cellular sites of uptake of the proteins were altered. Thus, 13H]RAFasialofetuin was recovered almost exclusively (\u3e90%) in the liver parenchymal cell fraction, while both [JHJRAF-labeled RNase B and heat-denatured albumin were recovered primarily (\u3e85%) in nonparenchymal cells. In addition, the RAF label was observed to reside stably (tl,2 \u3e 100 h) in the liver following degradation of the carrier protein; in contrast, radioactivity from “‘Ilabeled asialofetuin or RNase B was rapidly (tl,z \u3c 30 min) lost from liver. Radioactivity from 13H]RAF-proteins was recovered in a lysosomally enriched subcellular fraction in liver and consisted of a low molecular weight species (-llOO), containing both glucose and fructose in a ratio similar to that in the original protein. The results of these studies establish that 13H]RAF useful radioactive tracer for detecting the tissue and cellular sites of catabolism of long lived circulating proteins

A Post-Amadori Inhibitor Pyridoxamine Also Inhibits Chemical Modification of Proteins by Scavenging Carbonyl Intermediates of Carbohydrate and Lipid Degradation

Reactive carbonyl compounds are formed during autoxidation of carbohydrates and peroxidation of lipids. These compounds are intermediates in the formation of advanced glycation end products (AGE) and advanced lipoxidation end products (ALE) in tissue proteins during aging and in chronic disease. We studied the reaction of carbonyl compounds glyoxal (GO) and glycolaldehyde (GLA) with pyridoxamine (PM), a potent post-Amadori inhibitor of AGE formation in vitro and of development of renal and retinal pathology in diabetic animals. PM reacted rapidly with GO and GLA in neutral, aqueous buffer, forming a Schiff base intermediate that cyclized to a hemiaminal adduct by intramolecular reaction with the phenolic hydroxyl group of PM. This bicyclic intermediate dimerized to form a five-ring compound with a central piperazine ring, which was characterized by electrospray ionization-liquid chromatography/mass spectrometry, NMR, and x-ray crystallography. PM also inhibited the modification of lysine residues and loss of enzymatic activity of RNase in the presence of GO and GLA and inhibited formation of the AGE/ALE N(epsilon)-(carboxymethyl)lysine during reaction of GO and GLA with bovine serum albumin. Our data suggest that the AGE/ALE inhibitory activity and the therapeutic effects of PM observed in diabetic animal models depend, at least in part, on its ability to trap reactive carbonyl intermediates in AGE/ALE formation, thereby inhibiting the chemical modification of tissue proteins

Formation of Pentosidine during Nonenzymatic Browning of Proteins by Glucose

A fluorescent compound has been detected in proteins browned during Maillard reactions with glucose in vitro and shown to be identical to pentosidine, a pentose- derived fluorescent cross-link formed between arginine and lysine residues in collagen (Sell, D. R., and Monnier, V. M. (1989) J. Biol. Chem. 264, 21597- 2 1602). Pentosidine was the major fluorophore formed during nonenzymatic browning of ribonuclease and lysozyme by glucose, but accounted for \u3c1% of nondisulfide cross-links in protein dimers formed during the reaction. Pentosidine was formed in greatest yields in reactions of pentoses with lysine and arginine in model systems but was also formed from glucose, fructose, ascorbate, Amadori compounds, 3-deoxyglucosone, and other sugars. Pentosidine was not formed from peroxidized polyunsaturated fatty acids or malondialdehyde. Its formation from carbohydrates was inhibited under nitrogen or anaerobic conditions and by aminoguanidine, an inhibitor of advanced glycation and browning reactions. Pentosidine was detected in human lens proteins, where its concentration increased gradually with age, but it did not exceed trace concentrations (55 Fmol/mol lysine), even in the 80-year-old lens. Although its precise carbohydrate source in vivo is uncertain and it is present in only trace concentrations in tissue proteins, pentosidine appears to be a useful biomarker for assessing cumulative damage to proteins by nonenzymatic browning reactions with carbohydrates

A microrod-resonator Brillouin laser with 240 Hz absolute linewidth

Wedemonstrate an ultralow-noise microrod-resonator based laser that oscillates on the gain supplied by the stimulated Brillouin scattering optical nonlinearity. Microresonator Brillouin lasers are known to offer an outstanding frequency noise floor, which is limited by fundamental thermal fluctuations. Here, we show experimental evidence that thermal effects also dominate the close-to-carrier frequency fluctuations. The 6mmdiameter microrod resonator used in our experiments has a large optical mode area of∼100 μm2, and hence its 10 ms thermal time constant filters the close-to-carrier optical frequency noise. The result is an absolute laser linewidth of 240 Hz with a corresponding white-frequency noise floor of 0.1 Hz2 Hz−1.We explain the steady-state performance of this laser by measurements of its operation state and of its mode detuning and lineshape. Our results highlight a mechanism for noise that is common to many microresonator devices due to the inherent coupling between intracavity power and mode frequency.Wedemonstrate the ability to reduce this noise through a feedback loop that stabilizes the intracavity power.William Loh, Joe Becker, Daniel C Cole, Aurelien Coillet, Fred N Baynes, Scott B Papp and Scott A Diddam