Solar power satellite rectenna design study: Directional receiving elements and parallel-series combining analysis

Rectenna conversion efficiencies (RF to dc) approximating 85 percent were demonstrated on a small scale, clearly indicating the feasibility and potential of efficiency of microwave power to dc. The overall cost estimates of the solar power satellite indicate that the baseline rectenna subsystem will be between 25 to 40 percent of the system cost. The directional receiving elements and element extensions were studied, along with power combining evaluation and evaluation extensions

Real-time dynamics of clusters. III. I_2Ne_n (n=2–4), picosecond fragmentation, and evaporation

In this paper (III) we report real-time studies of the picosecond dynamics of iodine in Ne clusters I*2Nen(n = 2–4) --> I*2 + nNe. The results are discussed in relation to vibrational predissociation (VP), basic to the I2X systems, and to the onset of intramolecular vibrational-energy redistribution (IVR). The latter process, which is a precursor for the evaporation of the host atoms or for further fragmentation, is found to be increasingly effective as the cluster size increases; low-energy van der Waals modes act as the accepting (bath) modes. The reaction dynamics for I2Ne2 are examined and quantitatively compared to a simple model which describes the dynamics as consecutive bond breaking. On this basis, it is concluded that the onset of energy redistribution is observed in I2Ne2. Comparison of I2Ne and I2Ne2 to larger clusters (n=3,4) is accomplished by introducing an overall effective reaction rate. From measurements of the rates and their dependence on v[script ']i, the initial quantum number of the I2 stretch, we are able to examine the dynamics of direct fragmentation and evaporation, and compare with theory

Children with 5′-end NF1 gene mutations are more likely to have glioma

Objective:To ascertain the relationship between the germline NF1 gene mutation and glioma development in patients with neurofibromatosis type 1 (NF1).Methods:The relationship between the type and location of the germline NF1 mutation and the presence of a glioma was analyzed in 37 participants with NF1 from one institution (Washington University School of Medicine [WUSM]) with a clinical diagnosis of NF1. Odds ratios (ORs) were calculated using both unadjusted and weighted analyses of this data set in combination with 4 previously published data sets.Results:While no statistical significance was observed between the location and type of the NF1 mutation and glioma in the WUSM cohort, power calculations revealed that a sample size of 307 participants would be required to determine the predictive value of the position or type of the NF1 gene mutation. Combining our data set with 4 previously published data sets (n = 310), children with glioma were found to be more likely to harbor 5′-end gene mutations (OR = 2; p = 0.006). Moreover, while not clinically predictive due to insufficient sensitivity and specificity, this association with glioma was stronger for participants with 5′-end truncating (OR = 2.32; p = 0.005) or 5′-end nonsense (OR = 3.93; p = 0.005) mutations relative to those without glioma.Conclusions:Individuals with NF1 and glioma are more likely to harbor nonsense mutations in the 5′ end of the NF1 gene, suggesting that the NF1 mutation may be one predictive factor for glioma in this at-risk population.</jats:sec

Real-time dynamics of clusters. II. I_2X_n (n=1; X=He, Ne, and H_2), picosecond fragmentation

In this second paper (II) of a series, we report our picosecond time-resolved studies of the state-to-state rates of vibrational predissociation in iodine–rare gas (van der Waals) clusters. Particular focus is on the simplest system, I2He, which serves as a benchmark for theoretical modeling. Comparisons with I2Ne and I2H2 are also presented. The results from measurements made in real time are compared with those deduced from linewidth measurements, representing a rare example of a system studied by both methods under identical conditions and excited to the same quantum (v[script ']i) states. The discrepancies are discussed in relation to the origin of the broadening and preparation of the state. The rates as a function of v[script ']i display a nonlinear behavior which is examined in relation to the energy-gap law. The measured absolute rates and their dependence on v[script ']i are compared with numerous calculations invoking classical, quantum, and semiclassical theories. In the following paper (III in this series), the cluster size of the same system, I2Xn, is increased (n=2–4) and the dynamics are studied

Memorable And Secure: How Do You Choose Your PIN?

Managing all your PINs is difficult. Banks acknowledge this by allowing and facilitating PIN changes. However, choosing secure PINs is a difficult task for humans as they are incapable of consciously generating randomness. This leads to certain PINs being chosen more frequently than others, which in turn increases the danger of someone else guessing correctly. We investigate different methods of supporting PIN changes and report on an evaluation of these methods in a study with 152 participants. Our contribution is twofold: We introduce an alternative to system-generated random PINs, which considers people’s preferred memorisation strategy, and, secondly, we provide indication that presenting guidance on how to avoid insecure PINs does indeed nudge people towards more secure PIN choices when they are in the process of changing their PINs