We report on a laser locked to a silicon cavity operating continuously at 4 K with 1×10^{-16} instability and a median linewidth of 17 mHz at 1542 nm. This is a tenfold improvement in short-term ...instability, and a 10^{4} improvement in linewidth, over previous sub-10-K systems. Operating at low temperatures reduces the thermal noise floor and, thus, is advantageous toward reaching an instability of 10^{-18}, a long-sought goal of the optical clock community. The performance of this system demonstrates the technical readiness for the development of the next generation of ultrastable lasers that operate with an ultranarrow linewidth and long-term stability without user intervention.
Recent experiments have demonstrated that squeezed vacuum states can be injected into gravitational wave detectors to improve their sensitivity at detection frequencies where they are quantum noise ...limited. Squeezed states could be employed in the next generation of more sensitive advanced detectors currently under construction, such as Advanced LIGO, to further push the limits of the observable gravitational wave Universe. To maximize the benefit from squeezing, environmentally induced disturbances such as back scattering and angular jitter need to be mitigated. We discuss the limitations of current squeezed vacuum sources in relation to the requirements imposed by future gravitational wave detectors, and show a design for squeezed light injection which overcomes these limitations.
Sugar supplementation can stimulate rumen microbial growth and possibly fiber digestibility; however, excess ruminal carbohydrate availability relative to rumen-degradable protein (RDP) can promote ...energy spilling by microbes, decrease rumen pH, or depress fiber digestibility. Both RDP supply and rumen pH might be altered by forage source and monensin. Therefore, the objective of this study was to evaluate interactions of a sugar source (molasses) with monensin and 2 forage sources on rumen fermentation, total tract digestibility, and production and fatty acid composition of milk. Seven ruminally cannulated lactating Holstein cows were used in a 5×7 incomplete Latin square design with five 28-d periods. Four corn silage diets consisted of 1) control (C), 2) 2.6% molasses (M), 3) 2.6% molasses plus 0.45% urea (MU), or 4) 2.6% molasses plus 0.45% urea plus monensin sodium (Rumensin, at the intermediate dosage from the label, 16g/909kg of dry matter; MUR). Three chopped alfalfa hay diets consisted of 1) control (C), 2) 2.6% molasses (M), or 3) 2.6% molasses plus Rumensin (MR). Urea was added to corn silage diets to provide RDP comparable to alfalfa hay diets with no urea. Corn silage C and M diets were balanced to have 16.2% crude protein; and the remaining diets, 17.2% crude protein. Dry matter intake was not affected by treatment, but there was a trend for lower milk production in alfalfa hay diets compared with corn silage diets. Despite increased total volatile fatty acid and acetate concentrations in the rumen, total tract organic matter digestibility was lower for alfalfa hay-fed cows. Rumensin did not affect volatile fatty acid concentrations but decreased milk fat from 3.22 to 2.72% in corn silage diets but less in alfalfa hay diets. Medium-chain milk fatty acids (% of total fat) were lower for alfalfa hay compared with corn silage diets, and short-chain milk fatty acids tended to decrease when Rumensin was added. In whole rumen contents, concentrations of trans-10, cis-12C18:2 were increased when cows were fed corn silage diets. Rumensin had no effect on conjugated linoleic acid isomers in either milk or rumen contents but tended to increase the concentration of trans-10C18:1 in rumen samples. Molasses with urea increased ruminal NH3-N and milk urea N when cows were fed corn silage diets (6.8 vs. 11.3 and 7.6 vs. 12.0mg/dL for M vs. MU, respectively). Based on ruminal fermentation characteristics and fatty acid isomers in milk, molasses did not appear to promote ruminal acidosis or milk fat depression. However, combinations of Rumensin with corn silage-based diets already containing molasses and with a relatively high nonfiber carbohydrate:forage neutral detergent fiber ratio influenced biohydrogenation characteristics that are indicators of increased risk for milk fat depression.
Monensin (tradename: Rumensin) should reduce the extent of amino acid deamination in the rumen, and supplemental fat should decrease protozoal abundance and intraruminal N recycling. Because ...animal-vegetable (AV) fat can be biohydrogenated in the rumen and decrease its effectiveness as an anti-protozoal agent, we included diets supplemented with coconut oil (CNO) to inhibit protozoa. In a 6 × 6 Latin square design with a 2 × 3 factorial arrangement of treatments, 6 rumen-cannulated cows were fed diets without or with Rumensin (12g/909kg) and either no fat (control), 5% AV fat, or 5% CNO. The log10 concentrations (cells/mL) of total protozoa were not different between control (5.97) and AV fat (5.95) but were decreased by CNO (4.79; main effect of fat source). Entodinium and Dasytricha decreased as a proportion of total cells from feeding CNO, whereas Epidinium was unchanged in total abundance and thus increased proportionately. Total volatile fatty acid concentration was not affected by diet, but the acetate:propionate ratio decreased for CNO (1.85) versus control (2.95) or AV fat (2.58). Feeding CNO (23.8%) decreased ruminal neutral detergent fiber digestibility compared with control (31.1%) and AV fat (30.5%). The total-tract digestibility of NDF was lower for CNO (45.8%) versus control (57.0%) and AV fat (54.6%), with no difference in apparent organic matter digestibility (averaging 69.8%). The omasal flows of microbial N and non-ammonia N were lower for CNO versus control and AV fat, but efficiency of microbial protein synthesis was not affected. The dry matter intake was 4.5kg/d lower with CNO, which decreased milk production by 3.1kg/d. Main effect means of dry matter intake and milk yield tended to decrease by 0.7 and 1.2kg/d, respectively, when Rumensin was added. Both percentage and production of milk fat decreased for CNO (main effect of fat source). An interaction was observed such that AV decreased milk fat yield more when combined with Rumensin. Using large amounts of supplemental fat, especially CNO, to decrease abundance of protozoa requires further research to characterize benefits versus risks, especiallywhen combined with Rumensin.
Variation in milk fat percentage resulting from monensin supplementation to lactating dairy cows could be due to altered ruminal fermentation with interactions of monensin with ruminal ...biohydrogenation of fat and ruminal carbohydrate availability. The objective of the study was to determine the effects of feeding monensin as Rumensin (R) in diets differing in starch availability (ground or steam-flaked corn), effective fiber (long or short alfalfa hay, LAH or SAH), and 4% fat (F) from distillers grains, roasted soybeans, and an animal–vegetable blend on ruminal fermentation characteristics and milk production in lactating dairy cows. Six ruminally cannulated lactating Holstein cows were used in a balanced 6 × 6 Latin square design with 21-d periods. The cows were fed 6 diets: (1) C = control diet with ground corn and LAH, (2) CR = C plus R, (3) CRFL = CR plus F, (4) CRFS = ground corn, R, F, and SAH, (5) SRFL = steam-flaked corn, R, F, and LAH, and (6) SRFS = steam-flaked corn, R, F, and SAH. Mean particle size of LAH was 5.00 mm and 1.36 mm for SAH. All diets were formulated to have 21% forage NDF and 40% NFC. The R tended to decrease DMI, decreased milk fat yield, and numerically lowered milk fat percentage (3.41 vs. 2.98%). Addition of F to R diets did not affect milk fat percentage. By feeding diets containing R and F, SAH tended to increase milk fat percentage for the ground-corn diet, but SAH tended to decrease milk fat percentage with steam-flaked corn (CRFL + SRFS vs. CRFS + SRFL). The steam-flaked corn increased total-tract NDF digestibility (CRFL + CRFS vs. SRFL + SRFS; 51.1 vs. 56%). Addition of F with R decreased total VFA concentration and increased rumen pH. Fat addition with R decreased rumen NH3N and MUN (12.8 vs. 13.9 mg/dL), and SFC decreased NH3N concentration compared with ground corn. Although R caused milk fat depression, addition of F did not further exacerbate milk fat depression. Fatty acid analysis did not implicate any particular biohydrogenation intermediate as the causative factor for the milk fat depression.
Optical atomic clocks require local oscillators with exceptional optical coherence owing to the challenge of performing spectroscopy on their ultranarrow-linewidth clock transitions. Advances in ...laser stabilization have thus enabled rapid progress in clock precision. A new class of ultrastable lasers based on cryogenic silicon reference cavities has recently demonstrated the longest optical coherence times to date. Here we utilize such a local oscillator with two strontium (Sr) optical lattice clocks to achieve an advance in clock stability. Through an anti-synchronous comparison, the fractional instability of both clocks is assessed to be \4.8 \times 10^{ - 17}/\sqrt \tau\ for an averaging time τ (in seconds). Synchronous interrogation enables each clock to average at a rate of \3.5 \times 10^{ - 17}/\sqrt \tau\, dominated by quantum projection noise, and reach an instability of 6.6 × 10−19 over an hour-long measurement. The ability to resolve sub-10−18-level frequency shifts in such short timescales will affect a wide range of applications for clocks in quantum sensing and fundamental physics.
Epitaxial Py/Cu/Co/Cu(001) trilayers were patterned into micron sized disks and imaged using element-specific photoemission electron microscopy. By varying the Cu spacer layer thickness, we study how ...the coupling between the two magnetic layers influences the formation of magnetic vortex states. We find that while the Py and Co disks form magnetic vortex domains when the interlayer coupling is ferromagnetic, the magnetic vortex domains of the Py and Co disks break into anti-parallel aligned multidomains when the interlayer coupling is antiferromagnetic. We explain this result in terms of magnetic flux closure between the Py and Co layers for the antiferromagnetic coupling case.
•Corn silage can be fed as the sole forage to lactating cows with adequate effective fiber in diets.•Corn stover at 5.5% of the diet had no adverse effects on performance of lactating cows.•Feeding ...5% wheat straw resulted in the highest DMI but increasing wheat straw to 10% lowered DMI.•Balance of non-fiber carbohydrates and effective aNDF is important when feeding various forages.
The aim for this research was to determine if corn stover and wheat straw can be efficiently added to lactating dairy cow diets as physically effective neutral detergent fiber (peNDF) sources. A 5×5 Latin square design was used with 5 multiparous rumen cannulated Holstein cows. The treatments were: 1) corn silage as sole forage source 441g/kg of total-mixed ration (TMR); CS, 2) corn silage and 115g/kg alfalfa hay (455g/kg of forage in TMR; ALF), 3) corn silage and 50g/kg wheat straw (390g/kg of forage in TMR; STW-5), 4) corn silage and 100g/kg straw (462g/kg of forage in TMR; STW-10), and 5) corn silage and 55g/kg corn stover (395g/kg of forage in TMR; STV). All diets were formulated to contain 180g/kg forage aNDF except that the diet with 100g/kg straw contained 230g/kg forage aNDF. Dry matter intake (DMI) was highest for STW-5, except for it being similar with ALF. Body weight (734kg) and body condition score (3.18) were similar among treatments. Milk (35.6kg/d), milk fat (35.6g/kg), milk protein (28.7g/kg), and milk urea nitrogen (17.4mg/dL) also were similar among treatments. The different forage sources resulted in similar total tract digestibilities of dry matter (0.757), organic matter (0.769), and aNDF (0.635). Rumen pH (6.12), acetate:propionate (3.10), and ruminal concentrations of total volatile fatty acids and proportions of acetate, propionate, butyrate, and valerate were similar among treatments. Proportion of isovalerate and isobutyrate were highest for STW-10 compared to the other diets, and isovalerate was lower for ALF than for STW-5 and STW-10. Feeding 5% wheat straw resulted in the highest DMI, but increasing wheat straw to 10% lowered DMI, possibly caused by rumen fill. Feeding similar forage aNDF concentrations with corn silage based diets using corn stover, alfalfa hay, and wheat straw can result in similar animal performance and ruminal fermentation with adequate formulation of dietary non-fiber carbohydrates and peNDF.
Novel Noise Contributions in Crystalline Mirror Coatings Yu, J.; Legero, T.; Riehle, F. ...
2022 Joint Conference of the European Frequency and Time Forum and IEEE International Frequency Control Symposium (EFTF/IFCS),
2022-April-24
Conference Proceeding
SummaryWe discovered and characterized a novel birefringent noise in Al 0.92 Ga 0.08 As/GaAs crystalline mirror coatings at cryogenic temperature. We also determined the upper limit of coating ...Brownian noise in a reliable way. Our results indicate that excess noise related to semiconductor could be an obstacle to reaching the low Brownian thermal noise floor of these coatings. Our investigations on crystalline mirror coatings provide important design considerations for precision interferometry at cryogenic temperature.
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