1,772 research outputs found
A new wireless underground network system for continuous monitoring of soil water contents
A new stand-alone wireless embedded network system has been developed recently for continuous monitoring of soil water contents at multiple depths. This paper presents information on the technical aspects of the system, including the applied sensor technology, the wireless communication protocols, the gateway station for data collection, and data transfer to an end user Web page for disseminating results to targeted audiences. Results from the first test of the network system are presented and discussed, including lessons learned so far and actions to be undertaken in the near future to improve and enhance the operability of this innovative measurement approac
Finite Element Analysis of Custom Shoulder Implants Provides Accurate Prediction of Initial Stability
Custom reverse shoulder implants represent a valuable solution for patients with large bone defects. Since each implant has unique patient-specific features, finite element (FE) analysis has the potential to guide the design process by virtually comparing the stability of multiple configurations without the need of a mechanical test. The aim of this study was to develop an automated virtual bench test to evaluate the initial stability of custom shoulder implants during the design phase, by simulating a fixation experiment as defined by ASTM F2028-14. Three-dimensional (3D) FE models were generated to simulate the stability test and the predictions were compared to experimental measurements. Good agreement was found between the baseplate displacement measured experimentally and determined from the FE analysis (Spearman’s rank test, p < 0.05, correlation coefficient ¿s = 0.81). Interface micromotion analysis predicted good initial fixation (micromotion <150 µm, commonly used as bone ingrowth threshold). In conclusion, the finite element model presented in this study was able to replicate the mechanical condition of a standard test for a custom shoulder implants
Pitfalls in the design and analysis of paediatric clinical trials: a case of a ‘failed’ multi-centre study, and potential solutions
Aim: To increase awareness of possible pitfalls in the design and analysis of a multi-centre randomized clinical trial and to give an overview of alternative study designs and their consequences for power analyses in case of limited availability of trial participants
Фільтраційні справи радянських громадян, примусово вивезених до Німеччина в роки Великої Вітчизняної війни, як історичне джерело
We ask how incumbent car manufacturers and their political coalitions changed their political strategy with respect to the Californian zero emission vehicle mandate over the period 2000-2013. Building on the Corporate Political Activities literature we conceptualize firms' political strategies and their underlying tactics and actions. Our longitudinal case study builds on a dataset comprising governmental reports, documents, and public hearing transcripts, letters from industry, and complementary interviews with stakeholders. We find that car manufacturers became less defensive over time and more proactive and compliant in their political strategies towards the zero emission vehicle mandate. Car manufacturers' coalitions on the other hand, remain relatively defensive in their political actions as they continue to do the manufacturers' "dirty work". We provide insights in the Corporate Political Activities used to influence policymakers. To deal with industry opposition to policy interventions, our research suggests that policy makers might focus their interaction with industry on individual firms instead of industry associations, craft policies that stimulate competition between firms to break apart their closed industry front, and complement technology-forcing policies with demand-pull initiatives
Alternative reproductive tactics, sperm mobility and oxidative stress in Carollia perspicillata (Seba's short-tailed bat)
In social systems with alternative reproductive tactics, sneakers face a higher level of sperm competition than harem males and hence are predicted to allocate more resources to ejaculates. Antioxidants can protect sperm against oxidative stress, and thus, their allocation to the ejaculate may depend on mating tactic. In this study on the frugivorous bat Carollia perspicillata, we assessed, for harem and sneaker males, four spermmobility traits, blood and ejaculatemarkers of the redox balance and the ejaculate to blood ratios of the redox markers. Under higher sperm competition, sneaker males should allocate proportionally more antioxidant resources to the protection of sperm than harem males. In contrast, harem males should favour pre-copulatory functions, which comprise the protection of blood. We found significantly higher sperm velocity and sperm survival in sneakers. There was no correlation between spermmobility and spermenzymatic antioxidant activity or ejaculate levels of lipid peroxidation (oxidative damage). Ejaculate levels of lipid peroxidation and sperm survival showed a significantly positive correlation, which could be attributed to the role of reactive oxygen species for sperm capacitation. Harem and sneaker males showed similar levels of redox balance markers in ejaculate and blood. However, harem males showed a higher ratio of oxidized over reduced glutathione in blood, which may indicate higher cellular stress due to higher metabolism. Overall, our findings suggest that sneakers of C. perspicillata compensate for a higher level of sperm competition by higher sperm mobility.
Significance statement
In social systems with alternative reproductive tactics, sneakers face higher level of sperm competition than harem males and hence are predicted to allocate more resources to ejaculates. Antioxidants can protect sperm against oxidative stress, and thus, their allocation to the ejaculate may depend on mating tactic. In this study on the frugivorous bat Carollia perspicillata, we found sperm swimming significantly faster and longer in sneaker males compared to harem males. However, traits other than the investigated antioxidant may favour higher sperm mobility. Measured redox pattern in blood of harem males may indicate higher cellular stress due to higher metabolism. Our results provide support to the current sperm competition models at the intraspecific level, which is still debated for internal fertilizers. This study contributes to better understanding the trade-offs and adaptations resulting from alternative reproductive tactics in mammals
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