25,017 research outputs found
Temperature Effects on Development in \u3ci\u3eAphelinus Albipodus\u3c/i\u3e (Hymenoptera: Aphelinidae) From Two Geographic Regions
Aphelinus albipodus Hayat & Fatima was imported to the United States for classical biological control of the Russian wheat aphid, Diuraphis noxia (Mordvilko). Temperature effects on development of A. albipodus from two geographic regions (hereafter referred to as strains) were measured using the Russian wheat aphid as host. Temperature thresholds for egg to mummy, mummy to adult, and egg to adult development were 8.9,10.9, and 9.7°C for A. albipodus collected near Pingluo, China, and were and 8.5, 10.3, and 9.6°C for A. albipodus collected near Urumqi, China. The time required to develop from egg to adult did not differ among strains. However, when total immature development was partitioned into egg to mummy and mummy to adult, the time required for development through these two periods differed among strains. The Urumqi strain developed faster than the Pingluo strain from egg to mummy, while the Pingluo strain developed faster from mummy to adult. Degree-day requirements for egg to mummy development were 135 and 104 for the Pingluo and Urumqi strains, respectively. Corresponding requirements for mummy to adult development were 70 and 101 degree-days. The ability to vary immature development rate in response to climate or other factors could have adaptive significance because it would permit the parasitoid to exploit environments over a broad geographic range
Optical phase conjugation with less than a photon per degree of freedom
We demonstrate experimentally that optical phase conjugation can be used to
focus light through strongly scattering media even when far less than a photon
per optical degree of freedom is detected. We found that the best achievable
intensity contrast is equal to the total number of detected photons, as long as
the resolution of the system is high enough. Our results demonstrate that phase
conjugation can be used even when the photon budget is extremely low, such as
in high-speed focusing through dynamic media, or imaging deep inside tissue
Prediction of vertical bearing capacity of waveform micropile
This study proposes a predictive equation for bearing capacity considering the behaviour characteristics of a waveform micropile that can enhance the bearing capacity of a conventional micropile. The bearing capacity of the waveform micropile was analysed by a three-dimensional numerical model with soil and pile conditions obtained from the field and centrifuge tests. The load-transfer mechanism of the waveform micropile was revealed by the numerical analyses, and a new predictive equation for the bearing capacity was proposed. The bearing capacities of the waveform micropile calculated by the new equation were comparable with those measured from the field and centrifuge tests. This validated a prediction potential of the new equation for bearing capacity of waveform micropiles
Improving Drinking Water Quality in South Korea: A Choice Experiment with Hypothetical Bias Treatments
The objective of this present study is to use choice experiments and an extensive cost-benefit analysis (CBA) to investigate the feasibility of installing two advanced water treatments in Cheongju waterworks in South Korea. The study uses latent class attribute non-attendance models in a choice experiment setting in order to estimate the benefits of the two water treatments. Moreover, it explores strategies to mitigate potential hypothetical bias as this has been the strongest criticism brought to stated preference methods to date. Hypothetical bias is the difference between what people state in a survey they would be willing to pay and what they would actually pay in a real situation. The study employs cheap talk with a budget constraint reminder and honesty priming with the latter showing more evidence of reducing potential hypothetical bias. The lower bound of the median WTP (willingness to pay) for installing a new advanced water treatment system is approximately $2 US/month, similar to the average expenditures for bottled water per household in South Korea. These lower bounds were found using bootstrapping and simulations. The CBA shows that one of the two treatments, granular activated carbon is more robust to sensitivity analyses, making this the recommendation of the stud
Study on the global well-posedness for the two-dimensional Boussinesq and Lans-alpha magnetohydrodynamics equations
We investigate the global (in time) regularity problem for two different models; generalized two-dimensional Boussinesq and Lans-alpha magnetohydrodynamics system. First, the global regularity of 2D incompressible generalized Euler-Boussinesq equations has been studied. We establish the global existence and uniqueness of solutions to the initial-value problem when the velocity field is "double logarithmically" more singular than the one given by the Biot-Savart law. This global regularity result goes beyond the critical case. Secondly, we consider the two-dimensional Navier-Stokes-Boussinesq equations with logarithmically super-critical dissipation. By implementing Besov space technique, the global well-posedness of initial value problem is established. These results improve the existing results of super-critical Boussinesq system of equations. Finally, we study the two-dimensional generalized Lans-alpha magnetohydrodynamics system. We mainly focus on Lans-alpha magnetohydrodynamics system of equations with logarithmically weaker dissipation than full dissipation together with zero diffusion or zero dissipation and logarithmically weaker diffusion than full diffusion. In both cases, we are successful to resolve global regularity issues
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