1,226 research outputs found
Phenotypically Plastic Responses to Predation Risk Are Temperature Dependent
Predicting how organisms respond to climate change requires that we understand the temperature dependence of fitness in relevant ecological contexts (e.g., with or without predation risk). Predation risk often induces changes to life history traits that are themselves temperature dependent. We explore how perceived predation risk and temperature interact to determine fitness (indicated by the intrinsic rate of increase, r) through changes to its underlying components (net reproductive rate, generation time, and survival) in Daphnia magna. We exposed Daphnia to predation cues from dragonfly naiads early, late, or throughout their ontogeny. Predation risk increased r differentially across temperatures and depending on the timing of exposure to predation cues. The timing of predation risk likewise altered the temperature-dependent response of T and R0. Daphnia at hotter temperatures responded to predation risk by increasing r through a combination of increased R0 and decreased T that together countered an increase in mortality rate. However, only D. magna that experienced predation cues early in ontogeny showed elevated r at colder temperatures. These results highlight the fact that phenotypically plastic responses of life history traits to predation risk can be strongly temperature dependent
Using Triples to assess symmetry under weak dependence
The problem of assessing symmetry about an unspecified center of the one-dimensional
marginal distribution of strictly stationary random processes is considered. A well-known
U-statistic based on data triples is used to detect deviations from symmetry, allowing the
underying process to satisfy suitable mixing or near-epoch dependence conditions. We
suggest using subsampling for inference on the target parameter, establish the asymptotic
validity of the method in our setting, and discuss data-driven rules for selecting the size of
subsamples. The small-sample properties of the proposed inference procedures are examined
by means of Monte Carlo simulations and an application to time series of real output
growth is also presented
Modular digital holographic fringe data processing system
A software architecture suitable for reducing holographic fringe data into useful engineering data is developed and tested. The results, along with a detailed description of the proposed architecture for a Modular Digital Fringe Analysis System, are presented
Electric Drive for CIT Axial-Flow Test Blower
http://archive.org/details/electricdrivefor38vavrNAApproved for public release; distribution is unlimited
Magnetic properties of CuxMn1 x 3[Cr CN 6]2.zH2O complexes
Magnetization measurements were performed on the CuxMn1 x 3[Cr CN 6]2.zH2O molecule based magnets where x 0 0, 0.2, 0.25, 0.3, 0.35 0.4, 0.6, 0.8 and 1.0. Both the Curie temperature and saturated magnetization at first decrease with increasing value of x reaching the minimal value of TC 49 7 K and 0 17 B for x 0 2 and then increase with substitution. The pronounced hysteretic behavior between zero field cooled and field cooled regimes was observed for all samples. Magnetization changes the sign of magnetic polarization in zero field cooled magnetization curve at the compensation temperature Tcomp 16 K for sample with x 0 4. Our results indicate that the system behaves as mixed ferri ferromagnetic syste
Targeted Manipulation of Abundant and Rare Taxa in the Daphnia magna Microbiota with Antibiotics Impacts Host Fitness Differentially
Host-associated microbes contribute to host fitness, but it is unclear whether these contributions are from rare keystone taxa, numerically abundant taxa, or interactions among community members. Experimental perturbation of the microbiota can highlight functionally important taxa; however, this approach is primarily applied in systems with complex communities where the perturbation affects hundreds of taxa, making it difficult to pinpoint contributions of key community members. Here, we use the ecological model organism Daphnia magna to examine the importance of rare and abundant taxa by perturbing its relatively simple microbiota with targeted antibiotics. We used sublethal antibiotic doses to target either rare or abundant members across two temperatures and then measured key host life history metrics and shifts in microbial community composition. We find that removal of abundant taxa had greater impacts on host fitness than did removal of rare taxa and that the abundances of nontarget taxa were impacted by antibiotic treatment, suggesting that no rare keystone taxa exist in the Daphnia magna microbiota but that microbe-microbe interactions may play a role in host fitness. We also find that microbial community composition was impacted by antibiotics differently across temperatures, indicating that ecological context shapes within-host microbial responses and effects on host fitness
Radial-Inflow Turbines
http://archive.org/details/radialinflowturb40vav
Technical Development of a New Semispherical Radiofrequency Bipolar Device (RONJA): Ex Vivo and In Vivo Studies
The aim of this study is to inform about the development of a new semispherical surgical instrument for the bipolar multielectrode radiofrequency liver ablation. Present tools are universal; however they have several disadvantages such as ablation of healthy tissue, numerous needle punctures, and, therefore, longer operating procedure. Our newly designed and tested semispherical surgical tool can solve some of these disadvantages. By conducting an in vivo study on a set of 12 pigs, randomly divided into two groups, we have compared efficiency of the newly developed instrument with the commonly used device. Statistical analysis showed that there were no significant differences between the groups. On average, the tested instrument RONJA had shorter ablation time in both liver lobes and reduced the total operating time. The depth of the thermal alteration was on average 4 mm larger using the newly tested instrument. The new radiofrequency method described in this study could be used in open liver surgery for the treatment of small liver malignancies (up to 2 cm) in a single application with the aim of saving healthy liver parenchyma. Further experimental studies are needed to confirm these results before clinical application of the method in the treatment of human liver malignancies
Co-sputtered MoRe thin films for carbon nanotube growth-compatible superconducting coplanar resonators
Molybdenum rhenium alloy thin films can exhibit superconductivity up to
critical temperatures of . At the same time, the films are
highly stable in the high-temperature methane / hydrogen atmosphere typically
required to grow single wall carbon nanotubes. We characterize molybdenum
rhenium alloy films deposited via simultaneous sputtering from two sources,
with respect to their composition as function of sputter parameters and their
electronic dc as well as GHz properties at low temperature. Specific emphasis
is placed on the effect of the carbon nanotube growth conditions on the film.
Superconducting coplanar waveguide resonators are defined lithographically; we
demonstrate that the resonators remain functional when undergoing nanotube
growth conditions, and characterize their properties as function of
temperature. This paves the way for ultra-clean nanotube devices grown in situ
onto superconducting coplanar waveguide circuit elements.Comment: 8 pages, 6 figure
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