20,757 research outputs found
Silver oxide sorbent for carbon dioxide
Material can be regenerated at least 20 times by heating at 250 C. Sorbent is compatible with environment of high humidity; up to 20% by weight of carbon dioxide can be absorbed. Material is prepared from silver carbonate, potassium hydroxide or carbonate, and sodium silicate
Cassini's second and third laws
Cassinis second and third laws of moons rotational motion extended and applied to earth satellite, Mercyry, and Iapetu
Study of certain tether safety issues and the use of tethers for payload orbital transfer. Continuation of investigation of electrodynamic stabilization and control of long orbiting tethers
Tether safety issues are summarized
GABAB receptor ligands for the treatment of alcohol use disorder: preclinical and clinical evidence.
The present paper summarizes the preclinical and clinical studies conducted to define the "anti-alcohol" pharmacological profile of the prototypic GABAB receptor agonist, baclofen, and its therapeutic potential for treatment of alcohol use disorder (AUD). Numerous studies have reported baclofen-induced suppression of alcohol drinking (including relapse- and binge-like drinking) and alcohol reinforcing, motivational, stimulating, and rewarding properties in rodents and monkeys. The majority of clinical surveys conducted to date-including case reports, retrospective chart reviews, and randomized placebo-controlled studies-suggest the ability of baclofen to suppress alcohol consumption, craving for alcohol, and alcohol withdrawal symptomatology in alcohol-dependent patients. The recent identification of a positive allosteric modulatory binding site, together with the synthesis of in vivo effective ligands, represents a novel, and likely more favorable, option for pharmacological manipulations of the GABAB receptor. Accordingly, data collected to date suggest that positive allosteric modulators of the GABAB receptor reproduce several "anti-alcohol" effects of baclofen and display a higher therapeutic index (with larger separation-in terms of doses-between "anti-alcohol" effects and sedation)
Regular Moebius transformations of the space of quaternions
Let H be the real algebra of quaternions. The notion of regular function of a
quaternionic variable recently presented by G. Gentili and D. C. Struppa
developed into a quite rich theory. Several properties of regular quaternionic
functions are analogous to those of holomorphic functions of one complex
variable, although the diversity of the quaternionic setting introduces new
phenomena. This paper studies regular quaternionic transformations. We first
find a quaternionic analog to the Casorati-Weierstrass theorem and prove that
all regular injective functions from H to itself are affine. In particular, the
group Aut(H) of biregular functions on H coincides with the group of regular
affine transformations. Inspired by the classical quaternionic linear
fractional transformations, we define the regular fractional transformations.
We then show that each regular injective function from the Alexandroff
compactification of H to itself is a regular fractional transformation.
Finally, we study regular Moebius transformations, which map the unit ball B
onto itself. All regular bijections from B to itself prove to be regular
Moebius transformations.Comment: 12 page
Study of certain launching techniques using long orbiting tethers
A study of the basic equations governing orbital transfers using long orbiting tethers is presented. A very simple approximation to the general transfer equation is derived for the case of short tethers and low eccentricity orbits. Numerical examples are calculated for the case of injection into a circular orbit from a platform in eccentric orbit and injection into eccentric orbit from a platform in circular orbit. For the case of long tethers, a method is derived for reducing tether mass and increasing payload mass by tapering the tether to maintain constant stress per unit of tether cross section. Formulas are presented for calculating the equilibrium orbital parameters taking into account the mass of the platform, tether, and payload
The rotation of the planet Mercury
Rotation of planet Mercury from radar observation explained by solar gravitational torque on tidal deformation and equatorial plane asymmetr
An alternative option to the dual-probe out-of-ecliptic mission via Jupiter swingby
The possibility of having a high-inclination out-of-the-ecliptic probe complemented by a second probe going from Jupiter to the sun along a rectilinear path (at least for the segment from 0.3 a.u. inward to the sun) is theoretically examined. Orbit calculations of spacecraft trajectories are included
A new procedure to analyze RNA non-branching structures
RNA structure prediction and structural motifs analysis are challenging tasks in the investigation of RNA function. We propose a novel procedure to detect structural motifs shared between two RNAs (a reference and a target). In particular, we developed two core modules: (i) nbRSSP_extractor, to assign a unique structure to the reference RNA encoded by a set of non-branching structures; (ii) SSD_finder, to detect structural motifs that the target RNA shares with the reference, by means of a new score function that rewards the relative distance of the target non-branching structures compared to the reference ones. We integrated these algorithms with already existing software to reach a coherent pipeline able to perform the following two main tasks: prediction of RNA structures (integration of RNALfold and nbRSSP_extractor) and search for chains of matches (integration of Structator and SSD_finder)
Electrolytic pretreatment unit gaseous effluent conditioning
The electrolytic pretreatment of urine is an advanced process that eliminates the need for handling and storing the highly corrosive chemicals that are normally used in water reclamation systems. The electrolytic pretreatment process also converts the organic materials in urine to gases (N2 and O2) that can be used to replenish those lost to space by leakage, venting, and air lock operations. The electrolytic process is more than a pretreatment, since it decreases the urine solids content by approximately one third, thus reducing the load and eventual solids storage requirements of the urine processing system. The evolved gases from the pretreatment step cannot, however, be returned directly to the atmosphere of a spacecraft without first removing several impurities including hydrogen, chlorine, and certain organic compounds. A treatment concept was developed that would decrease the impurities in the gas stream that emanates from an electrolysis unit to levels sufficiently low to allow the conditioned gas stream to be safely discharged to a spacecraft atmosphere. Two methods were experimentally demonstrated that can accomplish the desired cleanup. The bases of the two methods are, repectively: (1) raw urine scrubbing and (2) silica gel sorption
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