1,416 research outputs found
Survival and Movement of Adult Rainbow Trout During Winter and Spring in the Henrys Fork of the Snake River
Discharge downstream from Island Park Dam on the Henrys Fork of the Snake River in Idaho is reduced each winter to facilitate storage of irrigation water. The effect this has on survival and movement of adult rainbow trout (Oncorhynchus mykiss) in this area is unknown. Additionally, fish movement during the spring has not been evaluated but may affect population estimates conducted in the tailwater monitoring area downstream from Island Park Dam prior to opening of fishing season. Therefore, we used radio telemetry to evaluate winter survival and movement of 61 adult rainbow trout in the Henrys Fork downstream from Island Park Dam under low and extremely low early winter flow conditions. Spring movement was also evaluated to asses whether the population estimates conducted in the monitoring area each spring represent fish from downstream adjacent reaches of the river, and how emigration between mark and recapture periods may affect the population estimate. Survival of radio-tagged trout was nearly 100 percent during early winter under both low and extremely low flow conditions and winter movement did not differ between the two years. Few radio-tagged rainbow trout from downriver were present in the monitoring reach during the time when the population estimate is normally conducted, indicating that large fluctuations in fish numbers in downstream reaches would likely be undetected based on population estimates conducted in the monitoring area. To remedy this, establishing a separate, regular population monitoring area in downstream reaches is recommended. We determined emigration from the monitoring reach between mark and recapture to have a minimal effect on the population estimate. However, we noted that all radio-tagged trout moving out of the monitoring reach during May moved into a short section of river between the monitoring reach and Island Park Dam, presumably to spawn. Therefore, emigration could be largely eliminated by extending the monitoring reach upstream to the dam
Show me the numbers: what data currently exist for nonānative species in the USA?
Nonānative species continue to be introduced to the United States from other countries via trade and transportation, creating a growing need for early detection and rapid response to new invaders. It is therefore increasingly important to synthesize existing data on nonānative species abundance and distributions. However, no comprehensive analysis of existing data has been undertaken for nonānative species, and there have been few efforts to improve collaboration. We therefore conducted a survey to determine what datasets currently exist for nonānative species in the US from county, state, multiāstate region, national, and global scales. We identified 319 datasets and collected metadata for 79% of these. Through this study, we provide a better understanding of extant nonānative species datasets and identify data gaps (ie taxonomic, spatial, and temporal) to help guide future survey, research, and predictive modeling efforts
Ejection fraction and mortality: A nationwide register-based cohort study of 499 153 women and men
Aims: We investigated the sex-based risk of mortality across the spectrum of left ventricular ejection fraction (LVEF) in a large cohort of patients in Australia.
Methods and results: Quantified levels of LVEF from 237ā046 women (48.1%) and 256ā109 men undergoing first-time, routine echocardiography (2000ā2019) were linked to 119ā232 deaths (median 5.6āyears of follow-up). Overall, 17.6% of men vs. 8.3% of women had an LVEF P\u3cā0.001] in women and 1.21 (95% CI 1.05ā1.39; P =ā0.008) in men. In women, an LVEF of 60.0ā64.9% was also associated with a HR 1.33 (95% CI 1.16ā1.52; P\u3cā0.001) for cardiovascular-related mortality. These associations were most striking in women and men aged
Conclusions: Among patients investigated for suspected or established cardiovascular disease, we found clinically relevant sex-based differences in the distribution and mortality associated with an LVE
Elevated micro-topography boosts growth rates in <i>Salicornia procumbens</i> by amplifying a tidally driven oxygen pump:Implications for natural recruitment and restoration
ā¢ Background and Aims: The growth rate of pioneer species is known to be a critical component determining recruitment success of marsh seedlings on tidal flats. By accelerating growth, recruits can reach a larger size at an earlier date, which reduces the length of the disturbance-free window required for successful establishment. Therefore, the pursuit of natural mechanisms that accelerate growth rates at a local scale may lead to a better understanding of the circumstances under which new establishment occurs, and may suggest new insights with which to perform restoration. This study explores how and why changes in local sediment elevation modify the growth rate of recruiting salt marsh pioneers. ā¢ Methods: A mesocosm experiment was designed in which the annual salt marsh pioneer Salicornia procumbens was grown over a series of raised, flat and lowered sediment surfaces, under a variety of tidal inundation regimes and in vertically draining or un-draining sediment. Additional physical tests quantified the effects of these treatments on sediment water-logging and oxygen dynamics, including the use of a planar optode experiment. ā¢ Key Results: In this study, the elevation of sediment micro-topography by 2 cm was the overwhelming driver of plant growth rates. Seedlings grew on average 25 % faster on raised surfaces, which represented a significant increase when compared to other groups. Changes in growth aligned well with the amplifying effect of raised sediment beds on a tidally episodic oxygenation process wherein sediment pore spaces were refreshed by oxygen-rich water at the onset of high tide. ā¢ Conclusions: Overall, the present study suggests this tidally driven oxygen pump as an explanation for commonly observed natural patterns in salt marsh recruitment near drainage channels and atop raised sediment mounds and reveals a promising way forward to promote the establishment of pioneers in the field
Thermal noise in interferometric gravitational wave detectors due to dielectric optical coatings
We report on thermal noise from the internal friction of dielectric coatings
made from alternating layers of Ta2O5 and SiO2 deposited on fused silica
substrates. We present calculations of the thermal noise in gravitational wave
interferometers due to optical coatings, when the material properties of the
coating are different from those of the substrate and the mechanical loss angle
in the coating is anisotropic. The loss angle in the coatings for strains
parallel to the substrate surface was determined from ringdown experiments. We
measured the mechanical quality factor of three fused silica samples with
coatings deposited on them. The loss angle of the coating material for strains
parallel to the coated surface was found to be (4.2 +- 0.3)*10^(-4) for
coatings deposited on commercially polished slides and (1.0 +- 0.3)*10^{-4} for
a coating deposited on a superpolished disk. Using these numbers, we estimate
the effect of coatings on thermal noise in the initial LIGO and advanced LIGO
interferometers. We also find that the corresponding prediction for thermal
noise in the 40 m LIGO prototype at Caltech is consistent with the noise data.
These results are complemented by results for a different type of coating,
presented in a companion paper.Comment: Submitted to LSC (internal) review Sept. 20, 2001. To be submitted to
Phys. Lett.
Getting It on Record: Issues and Strategies for Ethnographic Practice in Recording Studios
The recording studio has been somewhat neglected as a site for ethnographic fieldwork in the field of ethno-musicology and, moreover, the majority of published studies tend to overlook the specific concerns faced by the researcher within these contexts. Music recording studios can be places of creativity, artistry, and collaboration, but they often also involve challenging, intimidating, and fractious relations. Given that recording studios are, first and foremost, concerned with documenting musiciansā performances, we discuss the concerns of getting studio interactions āon recordā in terms of access, social relations, and methods of data collection. This article reflects on some of the issues we faced when conducting our fieldwork within British music recording facilities and makes suggestions based on strategies that we employed to address these issues
Planet-induced Stellar Pulsations in HAT-P-2's Eccentric System
Extrasolar planets on eccentric short-period orbits provide a laboratory in which to study radiative and tidal interactions between a planet and its host star under extreme forcing conditions. Studying such systems probes how the planet's atmosphere redistributes the time-varying heat flux from its host and how the host star responds to transient tidal distortion. Here, we report the insights into the planetāstar interactions in HAT-P-2's eccentric planetary system gained from the analysis of ~350 hr of 4.5 Ī¼m observations with the Spitzer Space Telescope. The observations show no sign of orbit-to-orbit variability nor of orbital evolution of the eccentric planetary companion, HAT-P-2 b. The extensive coverage allows us to better differentiate instrumental systematics from the transient heating of HAT-P-2 b's 4.5 Ī¼m photosphere and yields the detection of stellar pulsations with an amplitude of approximately 40 ppm. These pulsation modes correspond to exact harmonics of the planet's orbital frequency, indicative of a tidal origin. Transient tidal effects can excite pulsation modes in the envelope of a star, but, to date, such pulsations had only been detected in highly eccentric stellar binaries. Current stellar models are unable to reproduce HAT-P-2's pulsations, suggesting that our understanding of the interactions at play in this system is incomplete
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