Verified Correctness and Security of mbedTLS HMAC-DRBG

We have formalized the functional specification of HMAC-DRBG (NIST 800-90A), and we have proved its cryptographic security--that its output is pseudorandom--using a hybrid game-based proof. We have also proved that the mbedTLS implementation (C program) correctly implements this functional specification. That proof composes with an existing C compiler correctness proof to guarantee, end-to-end, that the machine language program gives strong pseudorandomness. All proofs (hybrid games, C program verification, compiler, and their composition) are machine-checked in the Coq proof assistant. Our proofs are modular: the hybrid game proof holds on any implementation of HMAC-DRBG that satisfies our functional specification. Therefore, our functional specification can serve as a high-assurance reference.Comment: Appearing in CCS '1

Fast nuclear rotation and octupole deformation

The Sm-150 nucleus has been studied to high spins in a measurement of gamma radiation following the Xe-136 (O-18,4n) Sm-150, compound-nucleus reaction at beam energy of 76 MeV. The measurement was performed at NBI Riso using the NORDBALL array. Alternating parity, epsilon = +1 band in Sm-150 has been observed up to spin I = 22. This band is crossed by two aligned bands, corresponding to a reflection-symmetric shape. After the second crossing the s = +1 band ends abruptly, suggesting that the octupole shape vanishes in Sm-150 above spin I = 22, as predicted by calculations. Other explanations, assuming continuation of the s = +1 band past the two alignments are also discussed

Fast nuclear rotation and octupole deformation

The Sm-150 nucleus has been studied to high spins in a measurement of gamma radiation following the Xe-136 (O-18,4n) Sm-150, compound-nucleus reaction at beam energy of 76 MeV. The measurement was performed at NBI Riso using the NORDBALL array. Alternating parity, epsilon = +1 band in Sm-150 has been observed up to spin I = 22. This band is crossed by two aligned bands, corresponding to a reflection-symmetric shape. After the second crossing the s = +1 band ends abruptly, suggesting that the octupole shape vanishes in Sm-150 above spin I = 22, as predicted by calculations. Other explanations, assuming continuation of the s = +1 band past the two alignments are also discussed

On the Reproducibility of Power Analyses in Motor Behavior Research

Recent metascience suggests that motor behavior research may be underpowered, on average. Researchers can perform a priori power analyses to ensure adequately powered studies. However, there are common pitfalls that can result in underestimating the required sample size for a given design and effect size of interest. Critical evaluation of power analyses requires successful analysis reproduction, which is conditional on the reporting of sufficient information. Here, we attempted to reproduce every power analysis reported in articles (k = 84/635) in three motor behavior journals between January 2019 and June 2021. We reproduced 7% of analyses using the reported information, which increased to 43% when we assumed plausible values for missing parameters. Among studies that reported sufficient information to evaluate, 63% reported using the same statistical test in the power analysis as in the study itself, and in 77%, the test addressed at least one of the identified hypotheses. Overall, power analyses were not commonly reported with sufficient information to ensure reproducibility. A nontrivial number of power analyses were also affected by common pitfalls. There is substantial opportunity to address the issue of underpowered research in motor behavior by increasing adoption of power analyses and ensuring reproducible reporting practices

Octupole Correlations in 145,146-Nd Nuclei

This research was sponsored by the National Science Foundation Grant NSF PHY-931478

Effects of elevated CO2 on grapevine (Vitis vinifera L.): Physiological and yield attributes

During the 2004, 2005 and 2006 growing seasons, physiological and anatomical leaf characteristics and productivity were studied in field-grown grapevines (Vitis vinifera L.) cv. 'Touriga Franca' under ambient (C, 365 ± 10 ppm) or elevated carbon dioxide [CO2] (E, 500 ± 16 ppm) under Open-top chambers (OTC-C and OTC-E, respectively). The elevated [CO2] concentration increased net photosynthetic rate (A), intrinsic water use efficiency (A/gs), leaf thickness, Mg concentration, C/N, K/N and Mg/N ratios and decreased stomatal density and N concentration. Nevertheless, stomatal conductance (gs), transpiration rate (E), photochemical efficiency (Fv/Fm), leaf water potential, SPAD-values and Red/Far-red ratio transmitted by leaves were not significantly affected by [CO2]. Meanwhile, there is no evidence for downward acclimation of photosynthesis and stomatal conductance. Yield, cluster weight and vigour showed an increase in elevated [CO2] treatment but yield to pruning mass ratio was unaffected. Despite elevated [CO2] stimulates grapevine photosynthesis and yield, more long-term studies, particularly at sub-optimal nutrient and water availability, are needed in order to reveal the grapevine responses to climate change in the Mediterranean area.