Effects of helium and nitrogen as pressurants in nitrogen tetroxide transfer

Study investigates effects of helium and nitrogen as pressurants in nitrogen tetroxide transfer from one vessel to another at a higher elevation. Results may contribute to creation of new environmental systems and improved oxygen solubility in water to promote fish life

Predicting surface heating rates and pressures resulting from hot exhaust gases

Structural tests determine experimentally the amount of thermal protection required on the Apollo service module because of plume impingement heating. Exhaust flow field analysis correlates with flat plate heating rate and surface pressure in a vacuum

Continuously non-malleable codes with split-state refresh

Non-malleable codes for the split-state model allow to encode a message into two parts, such that arbitrary independent tampering on each part, and subsequent decoding of the corresponding modified codeword, yields either the same as the original message, or a completely unrelated value. Continuously non-malleable codes further allow to tolerate an unbounded (polynomial) number of tampering attempts, until a decoding error happens. The drawback is that, after an error happens, the system must self-destruct and stop working, otherwise generic attacks become possible. In this paper we propose a solution to this limitation, by leveraging a split-state refreshing procedure. Namely, whenever a decoding error happens, the two parts of an encoding can be locally refreshed (i.e., without any interaction), which allows to avoid the self-destruct mechanism in some applications. Additionally, the refreshing procedure can be exploited in order to obtain security against continual leakage attacks. We give an abstract framework for building refreshable continuously non-malleable codes in the common reference string model, and provide a concrete instantiation based on the external Diffie–Hellman assumption. Finally, we explore applications in which our notion turns out to be essential. The first application is a signature scheme tolerating an arbitrary polynomial number of split-state tampering attempts, without requiring a self-destruct capability, and in a model where refreshing of the memory happens only after an invalid output is produced. This circumvents an impossibility result from a recent work by Fujisaki and Xagawa (Asiacrypt 2016). The second application is a compiler for tamper-resilient read-only RAM programs. In comparison to other tamper-resilient RAM compilers, ours has several advantages, among which the fact that, in some cases, it does not rely on the self-destruct feature

Best Practices in Second Stage Labor Care: Maternal Bearing Down and Positioning

Despite evidence of adverse fetal and maternal outcomes from the use of sustained Valsalva bearing down efforts, current second-stage care practices are still characterized by uniform directions to “push” forcefully upon complete dilatation of the cervix while the woman is in a supine position. Directed pushing might slightly shorten the duration of second stage labor, but can also contribute to deoxygenation of the fetus; cause damage to urinary, pelvic, and perineal structures; and challenge a woman’s confidence in her body. Research on the second stage of labor care is reviewed, with a focus on recent literature on maternal bearing down efforts, the “laboring down” approach to care, second-stage duration, and maternal position. Clinicians can apply the scientific evidence regarding the detrimental effects of sustained Valsalva bearing down efforts and supine positioning by individualizing second stage labor care and supporting women’s involuntary bearing down sensations that can serve to guide her behaviors

Extended Emission Line Gas in Radio Galaxies - PKS0349-27

PKS0349-27 is a classical FRII radio galaxy with an AGN host which has a spectacular, spiral-like structure in its extended emission line gas (EELG). We have measured the velocity field in this gas and find that it splits into 2 cloud groups separated by radial velocities which at some points approach 400 km/s Measurements of the diagnostic emission line ratios [OIII]5007/H-beta, [SII]6716+6731/H-alpha, and [NII]6583/H-alpha in these clouds show no evidence for the type of HII region emission associated with starburst activity in either velocity system. The measured emission line ratios are similar to those found in the nuclei of narrow-line radio galaxies, but the extended ionization/excitation cannot be produced by continuum emission from the active nucleus alone. We present arguments which suggest that the velocity disturbances seen in the EELG are most likely the result of a galaxy-galaxy collision or merger but cannot completely rule out the possibility that the gas has been disrupted by the passage of a radio jet.Comment: 12 pages, 3 fig pages, to appear in the Astrophys.

CRISPR/Cas9-mediated mutagenesis of phytoene desaturase in diploid and octoploid strawberry

Background: Gene editing using CRISPR/Cas9 is a simple and powerful tool for elucidating genetic controls and for crop improvement and its use has been reported in a growing number of important food crops, including recently Fragaria. In order to inform application of the technology in Fragaria, we targeted the visible endogenous marker gene PDS (phytoene desaturase) in diploid Fragaria vesca ssp. vesca ‘Hawaii 4’ and octoploid F. × ananassa ‘Calypso’. Results: Agrobacterium-mediated transformation of leaf and petiole explants was used for efficient stable integration of constructs expressing plant codon-optimised Cas9 and single guide sequences under control of the Arabidopsis U6-26 consensus promoter and terminator or Fragaria vesca U6III regulatory sequences. More than 80% (‘Hawaii 4’) and 50% (‘Calypso’) putative transgenic shoot lines (multiple shoots derived from a single callus) exhibited mutant phenotypes. Of mutant shoot lines selected for molecular analysis, approximately 75% (‘Hawaii 4’) and 55% (‘Calypso’) included albino regenerants with bi-allelic target sequence variants. Our results indicate the PDS gene is functionally diploid in ‘Calypso’. Conclusion: We demonstrate that CRISPR/Cas9 may be used to generate biallelic mutants at high frequency within the genomes of diploid and octoploid strawberry. The methodology, observations and comprehensive data set pre- sented will facilitate routine application of this technology in Fragaria to single and multiple gene copy targets where mutant phenotypes cannot be identified visually

Integral Field Spectroscopy of 23 Spiral Bulges

We have obtained Integral Field Spectroscopy for 23 spiral bulges using INTEGRAL on the William Herschel Telescope and SPIRAL on the Anglo-Australian Telescope. This is the first 2D survey directed solely at the bulges of spiral galaxies. Eleven galaxies of the sample do not have previous measurements of the stellar velocity dispersion (sigma*). These data are designed to complement our Space Telescope Imaging Spectrograph program for estimating black hole masses in the range 10^6-10^8M_sun using gas kinematics from nucleated disks. These observations will serve to derive the stellar dynamical bulge properties using the traditional Mgb and CaII triplets. We use both Cross Correlation and Maximum Penalized Likelihood to determine projected sigma* in these systems and present radial velocity fields, major axis rotation curves, curves of growth and sigma* fields. Using the Cross Correlation to extract the low order 2D stellar dynamics we generally see coherent radial rotation and irregular velocity dispersion fields suggesting that sigma* is a non-trivial parameter to estimate.Comment: 11 pages, 30 figures, accepted for publication in ApJ

Human dynamics revealed through Web analytics

When the World Wide Web was first conceived as a way to facilitate the sharing of scientific information at the CERN (European Center for Nuclear Research) few could have imagined the role it would come to play in the following decades. Since then, the increasing ubiquity of Internet access and the frequency with which people interact with it raise the possibility of using the Web to better observe, understand, and monitor several aspects of human social behavior. Web sites with large numbers of frequently returning users are ideal for this task. If these sites belong to companies or universities, their usage patterns can furnish information about the working habits of entire populations. In this work, we analyze the properly anonymized logs detailing the access history to Emory University's Web site. Emory is a medium size university located in Atlanta, Georgia. We find interesting structure in the activity patterns of the domain and study in a systematic way the main forces behind the dynamics of the traffic. In particular, we show that both linear preferential linking and priority based queuing are essential ingredients to understand the way users navigate the Web.Comment: 7 pages, 8 figure