Sealed containers in Z

Physical means of securing information, such as sealed envelopes and scratch cards, can be used to achieve cryptographic objectives. Reasoning about this has so far been informal. We give a model of distinguishable sealed envelopes in Z, exploring design decisions and further analysis and development of such models

The Porphyromonas gingivalis hemagglutinins HagB and HagC are major mediators of adhesion and biofilm formation

Porphyromonas gingivalis is a bacterium associated with chronic periodontitis that possesses a family of genes encoding hemagglutinins required for heme acquisition. In this study we generated ΔhagB and ΔhagC mutants in strain W83 and demonstrate that both hagB and hagC are required for adherence to oral epithelial cells. Unexpectedly, a double ΔhagB/ΔhagC mutant had less severe adherence defects than either of the single mutants, but was found to exhibit increased expression of the gingipain-encoding genes rgpA and kgp, suggesting that a ΔhagB/ΔhagC mutant is only viable in populations of cells that exhibit increased expression of genes involved in heme acquisition. Disruption of hagB in the fimbriated strain ATCC33277 demonstrated that HagB is also required for stable attachment of fimbriated bacteria to oral epithelial cells. Mutants of hagC were also found to form defective single and multi-species biofilms that had reduced biomass relative to biofilms formed by the wild-type strain. This study highlights the hitherto unappreciated importance of these genes in oral colonization and biofilm formation

Limits on Clouds and Hazes for the TRAPPIST-1 Planets

The TRAPPIST-1 planetary system is an excellent candidate for study of the evolution and habitability of M-dwarf planets. Transmission spectroscopy observations performed with the Hubble Space Telescope (HST) suggest the innermost five planets do not possess clear hydrogen atmospheres. Here we reassess these conclusions with recently updated mass constraints and expand the analysis to include limits on metallicity, cloud top pressure, and the strength of haze scattering. We connect recent laboratory results of particle size and production rate for exoplanet hazes to a one-dimensional atmospheric model for TRAPPIST-1 transmission spectra. Doing so, we obtain a physically-based estimate of haze scattering cross sections. We find haze scattering cross sections on the order of 1e-26 to 1e-19 cm squared are needed in hydrogen-rich atmospheres for TRAPPIST-1 d, e, and f to match the HST data. For TRAPPIST-1 g, we cannot rule out a clear hydrogen-rich atmosphere. We also modeled the effects an opaque cloud deck and substantial heavy element content have on the transmission spectra. We determine that hydrogen-rich atmospheres with high altitude clouds, at pressures of 12mbar and lower, are consistent with the HST observations for TRAPPIST-1 d and e. For TRAPPIST-1 f and g, we cannot rule out clear hydrogen-rich cases to high confidence. We demonstrate that metallicities of at least 60xsolar with tropospheric (0.1 bar) clouds agree with observations. Additionally, we provide estimates of the precision necessary for future observations to disentangle degeneracies in cloud top pressure and metallicity. Our results suggest secondary, volatile-rich atmospheres for the outer TRAPPIST-1 planets d, e, and f.Comment: 15 pages, 3 figures, 2 tables, accepted in the Astronomical Journa

Polarized Broad H-alpha Emission from the LINER Nucleus of NGC 1052

Optical spectropolarimetry of the nucleus of the LINER NGC 1052, obtained at the Keck Observatory, reveals a rise in polarization in the wings of the H-alpha line profile. The polarization vector of H-alpha is offset by 67 degrees from the parsec-scale radio axis and by 83 degrees from the kiloparsec-scale radio axis, roughly in accord with expectations for scattering within the opening cone of an obscuring torus. The broad component of H-alpha has FWHM ~ 2100 km/s in total flux and FWHM ~ 5000 km/s in polarized light. Scattering by electrons is the mechanism most likely responsible for this broadening, and we find T_e ~ 10^5 K for the scattering medium, similar to values observed in Seyfert 2 nuclei. This is the first detection of a polarized broad emission line in a LINER, demonstrating that unified models of active galactic nuclei are applicable to at least some LINERs.Comment: 6 pages, 2 figures, prepared using the emulateapj style file, accepted for publication in The Astrophysical Journal Letter

Electron microscopic and biochemical characterization of Fraction 1 protein

High resolution electron microscopy of Fraction I protein from plant leave

BIOMECHANICS OF RUNNING - Electromyographic Analysis of the Hip during Jogging, Running and Sprinting

The patterns of muscle action during human locomotion have been investigated for several decades. Lower extremity electromyographic activity in walking was investigated by Bartholomew and the Prosthetic Research Group at Berkeley in 1953. (1) Others investigated the actions of specific muscles during various leg movements. Basmajian and LeBan et al. (6) examined the electromyographic action of the iliopsoas muscle. These studies have led to the investigation of running. Saito et aI., (10) presented temporal data on the gait cycle of running. James and Brubaker (5) presented a descriptive analysis of running. Other researchers have directed their work toward sprinting: Fenn (4) investigated frictional and kinetic factors in 1930, and Dillman (3) and Ralph Mann (7) used kinetic analysis. Mann and Hagy (9) and Mann et aI. (8) investigated temporal and electromyographic patterns of walking, running and sprinting. This study investigates and describes the electromyographic activity ofthe lower extrJmities and trunk musculature duringjogging, running, and sprinting

Reconciling taxonomy and phylogenetic inference: formalism and algorithms for describing discord and inferring taxonomic roots

Although taxonomy is often used informally to evaluate the results of phylogenetic inference and find the root of phylogenetic trees, algorithmic methods to do so are lacking. In this paper we formalize these procedures and develop algorithms to solve the relevant problems. In particular, we introduce a new algorithm that solves a "subcoloring" problem for expressing the difference between the taxonomy and phylogeny at a given rank. This algorithm improves upon the current best algorithm in terms of asymptotic complexity for the parameter regime of interest; we also describe a branch-and-bound algorithm that saves orders of magnitude in computation on real data sets. We also develop a formalism and an algorithm for rooting phylogenetic trees according to a taxonomy. All of these algorithms are implemented in freely-available software.Comment: Version submitted to Algorithms for Molecular Biology. A number of fixes from previous versio

Statistical analysis of general aviation VG-VGH data

To represent the loads spectra of general aviation aircraft operating in the Continental United States, VG and VGH data collected since 1963 in eight operational categories were processed and analyzed. Adequacy of data sample and current operational categories, and parameter distributions required for valid data extrapolation were studied along with envelopes of equal probability of exceeding the normal load factor (n sub z) versus airspeed for gust and maneuver loads and the probability of exceeding current design maneuver, gust, and landing impact n sub z limits. The significant findings are included

Does online sexually transmitted infection screening compromise care? A service evaluation comparing the management of chlamydial infection diagnosed online and in clinic

Patient demand on sexual health services (SHS) in the UK is so high that many services have introduced online screening to accommodate more patients. There are concerns that these services may not be accessible to all. This service evaluation was undertaken to determine whether online screening is accessible by those patients most at need by comparing the demographics and number of asymptomatic chlamydial infections detected online and in clinic. No difference was found in the age nor level of deprivation, demonstrating that online services are an accessible way to screen for STIs without overburdening established services