Prediction of annual joint rain fade on EHF networks by weighted rain field selection

©2015. American Geophysical Union. All Rights Reserved. We present a computationally efficient method to predict joint rain fade on arbitrary networks of microwave links. Methods based on synthetic rain fields composed of a superposition of rain cells have been shown to produce useful predictions of joint fade, with low computational overhead. Other methods using rain fields derived from radar systems have much higher computational overhead but provide better predictions. The proposed method combines the best features of both methods by using a small number of measured rain fields to produce annual fade predictions. Rain fields are grouped into heavy rain and light rain groups by maximum rain rate. A small selection of rain fields from each group are downscaled and fade predictions generated by pseudointegration of specific attenuation. This paper presents a method to optimize the weights used to combine the heavy rain and light rain fade predictions to yield an estimate of the average annual distribution. The algorithm presented yields estimates of average annual fade distributions with an error small compared to year-to-year variation, using only 0.2% of the annual data set of rain fields

Phase Transitions in liquid Helium 3

The phase transitions of liquid Helium 3 are described by truncations of an exact nonperturbative renormalization group equation. The location of the first order transition lines and the jump in the order parameter are computed quantitatively. At the triple point we find indications for partially universal behaviour. We suggest experiments that could help to determine the effective interactions between fermion pairs.Comment: 4 pages, 6 figures, LaTe

Analysis of how Dual-tasking Effects Selected Gait Variables in Older Adults with a Known Relative Power

Please view abstract in the attached PDF file

Integrating Systems around the User: Combining Isabelle, Maple, and QEPCAD in the Prover's Palette

AbstractWe describe the Proverʼs Palette, a general, modular architecture for combining tools for formal verification, with the key differentiator that the integration emphasises the role of the user. A concrete implementation combining the theorem prover Isabelle with the computer algebra systems Maple and QEPCAD-B is then presented. This illustrates that the design principles of the Proverʼs Palette simplify tool integrations while enhancing the power and usability of theorem provers

Individual-specific changes in the human gut microbiota after challenge with enterotoxigenic Escherichia coli and subsequent ciprofloxacin treatment

Acknowledgements The authors wish to thank Mark Stares, Richard Rance, and other members of the Wellcome Trust Sanger Institute’s 454 sequencing team for generating the 16S rRNA gene data. Lili Fox Vélez provided editorial support. Funding IA, JNP, and MP were partly supported by the NIH, grants R01-AI-100947 to MP, and R21-GM-107683 to Matthias Chung, subcontract to MP. JNP was partly supported by an NSF graduate fellowship number DGE750616. IA, JNP, BRL, OCS and MP were supported in part by the Bill and Melinda Gates Foundation, award number 42917 to OCS. JP and AWW received core funding support from The Wellcome Trust (grant number 098051). AWW, and the Rowett Institute of Nutrition and Health, University of Aberdeen, receive core funding support from the Scottish Government Rural and Environmental Science and Analysis Service (RESAS).Peer reviewedPublisher PD

Walking-Induced Fatigue Leads to Increased Risk in Older Adults

Background- For older adults, falls are a serious health problem, with more than 30% of people older than 65 suffering a fall at least once a year. One element often overlooked in the assessment of falls is whether a person\u27s balance, walking ability, and overall falls risk is affected by performing activities of daily living such as walking. Objective- This study assessed the immediate impact of incline walking at a moderate pace on falls risk, leg strength, reaction time, gait, and balance in 75 healthy adults from 30 to 79 years of age. Subjects were subdivided into 5 equal groups based on their age (group 1, 30-39 years; group 2, 40-49 years; group 3, 50-59 years; group 4, 60-69 years; group 5, 70-79 years). Methods- Each person\u27s falls risk (using the Physiological Profile Assessment), simple reaction time, leg strength, walking ability, and standing balance were assessed before and after a period of incline walking on an automated treadmill. The walking task consisted of three 5-minute trials at a faster than preferred pace. Fatigue during walking was elicited by increasing the treadmill incline in increments of 2 degrees (from level) every minute to a maximum of 8 degrees. Results- As predicted, significant age-related differences were observed before the walking activity. In general, increasing age was associated with declines in gait speed, lower limb strength, slower reaction times, and increases in overall falls risk. Following the treadmill task, older adults exhibited increased sway (path length 60-69 years; 10.2 ± 0.7 to 12.1 ± 0.7 cm: 70-79 years; 12.8 ± 1.1 to 15.1 ± 0.8 cm), slower reaction times (70-79 years; 256 ± 6 to 287 ± 8 ms), and declines in lower limb strength (60-69 years; 36 ± 2 to 31 ± 1 kg: 70-79 years; 32.3 ± 2 to 27 ± 1 kg). However, a significant increase in overall falls risk (pre; 0.51 ± 0.17: post; 1.01 ± 0.18) was only seen in the oldest group (70-79 years). For all other persons (30-69 years), changes resulting from the treadmill-walking task did not lead to a significant increase in falls risk. Conclusions: As most falls occur when an individual is moving and/or fatigued, assessing functional properties related to balance, gait, strength, and falls risk in older adults both at rest and following activity may provide additional insight

Starspot-induced optical and infrared radial velocity variability in T Tauri star Hubble 4

We report optical (6150 Ang) and K-band (2.3 micron) radial velocities obtained over two years for the pre-main sequence weak-lined T Tauri star Hubble I 4. We detect periodic and near-sinusoidal radial velocity variations at both wavelengths, with a semi-amplitude of 1395\pm94 m/s in the optical and 365\pm80 m/s in the infrared. The lower velocity amplitude at the longer wavelength, combined with bisector analysis and spot modeling, indicates that there are large, cool spots on the stellar surface that are causing the radial velocity modulation. The radial velocities maintain phase coherence over hundreds of days suggesting that the starspots are long-lived. This is one of the first active stars where the spot-induced velocity modulation has been resolved in the infrared.Comment: Accepted for publication in The Astrophysical Journa

Analysis of Strong-Coupling Parameters for Superfluid 3He

Superfluid $^{3}$He experiments show strong deviation from the weak-coupling limit of the Ginzburg-Landau theory, and this discrepancy grows with increasing pressure. Strong-coupling contributions to the quasiparticle interactions are known to account for this effect and they are manifest in the five $\beta$-coefficients of the fourth order Ginzburg-Landau free energy terms. The Ginzburg-Landau free energy also has a coefficient $g_{z}$ to include magnetic field coupling to the order parameter. From NMR susceptibility experiments, we find the deviation of $g_{z}$ from its weak-coupling value to be negligible at all pressures. New results for the pressure dependence of four different combinations of $\beta$-coefficients, $\beta$_{345}, $\beta$_{12}, $\beta$_{245}, and $\beta$_{5} are calculated and comparison is made with theory.Comment: 6 pages, 2 figures, 1 table. Manuscript prepared for QFS200

Security Theorems via Model Theory

A model-theoretic approach can establish security theorems for cryptographic protocols. Formulas expressing authentication and non-disclosure properties of protocols have a special form. They are quantified implications for all xs . (phi implies for some ys . psi). Models (interpretations) for these formulas are *skeletons*, partially ordered structures consisting of a number of local protocol behaviors. Realized skeletons contain enough local sessions to explain all the behavior, when combined with some possible adversary behaviors. We show two results. (1) If phi is the antecedent of a security goal, then there is a skeleton A_phi such that, for every skeleton B, phi is satisfied in B iff there is a homomorphism from A_phi to B. (2) A protocol enforces for all xs . (phi implies for some ys . psi) iff every realized homomorphic image of A_phi satisfies psi. Hence, to verify a security goal, one can use the Cryptographic Protocol Shapes Analyzer CPSA (TACAS, 2007) to identify minimal realized skeletons, or "shapes," that are homomorphic images of A_phi. If psi holds in each of these shapes, then the goal holds