28,642 research outputs found
Carbon deposition in the Bosch process with ruthenium and ruthenium-iron alloy catalysts
The effectiveness of ruthenium and the alloys 50Ru50Fe and 33Ru67Fe as alternatives to iron, nickel, and cobalt catalysts in recovering oxygen from metabolic carbon dioxide was investigated. Carbon deposition boundaries over the unsupported alloys are reported. Experiments were also carried out over 50Ru50Fe and 97Ru3Fe3 catalysts supported on gamma-alumina to determine their performance in the synthesis of low molecular weight olefins. High production of ethylene and propylene would be beneficial for an improvement of an overall Bosch process, as a gas phase containing high olefin content would enhance carbon deposition in a Bosch reactor
Radiation Information from 1958 δ2
The telemetered radiation information from the satellite 1958 δ2
(Sputnik III) has been analyzed for sixty-two separate passes recorded
in College, Alaska. The data indicate a dependence of radiation intensity
on altitude in the range 250-500 km. Both the high and low
energy components apparently contribute to the overall increase of
intensity with altitude, but the presence of a continuous afterglow
in the scintillating crystal prevented detailed interpretation of the
results.IGY Project No. 32.42
NSF Grant No. Y/32.42/268Ye
DNA Sequence Determinants Controlling Affinity, Stability and Shape of DNA Complexes Bound by the Nucleoid Protein Fis.
The abundant Fis nucleoid protein selectively binds poorly related DNA sequences with high affinities to regulate diverse DNA reactions. Fis binds DNA primarily through DNA backbone contacts and selects target sites by reading conformational properties of DNA sequences, most prominently intrinsic minor groove widths. High-affinity binding requires Fis-stabilized DNA conformational changes that vary depending on DNA sequence. In order to better understand the molecular basis for high affinity site recognition, we analyzed the effects of DNA sequence within and flanking the core Fis binding site on binding affinity and DNA structure. X-ray crystal structures of Fis-DNA complexes containing variable sequences in the noncontacted center of the binding site or variations within the major groove interfaces show that the DNA can adapt to the Fis dimer surface asymmetrically. We show that the presence and position of pyrimidine-purine base steps within the major groove interfaces affect both local DNA bending and minor groove compression to modulate affinities and lifetimes of Fis-DNA complexes. Sequences flanking the core binding site also modulate complex affinities, lifetimes, and the degree of local and global Fis-induced DNA bending. In particular, a G immediately upstream of the 15 bp core sequence inhibits binding and bending, and A-tracts within the flanking base pairs increase both complex lifetimes and global DNA curvatures. Taken together, our observations support a revised DNA motif specifying high-affinity Fis binding and highlight the range of conformations that Fis-bound DNA can adopt. The affinities and DNA conformations of individual Fis-DNA complexes are likely to be tailored to their context-specific biological functions
Understanding the role of shame and its consequences in female hypersexual behaviours: A pilot study
Background and aims:
Hypersexuality and sexual addiction among females is a little understudied phenomenon. Shame is thought to be intrinsic to hypersexual behaviours, especially in women. Therefore, the aim of this study was to understand both hypersexual behaviours and consequences of hypersexual behaviours and their respective contributions to shame in a British sample of females (n = 102).
Methods:
Data were collected online via Survey Monkey.
Results:
Results showed the Sexual Behaviour History (SBH) and the Hypersexual Disorder Questionnaire (HDQ) had significant positive correlation with scores on the Shame Inventory. The results indicated that hypersexual behaviours (HBI and HDQ) were able to predict a small percentage of the variability in shame once sexual orientation (heterosexual vs. non-heterosexual) and religious beliefs (belief vs. no belief) were controlled for. Results also showed there was no evidence that religious affiliation and/or religious beliefs had an influence on the levels of hypersexuality and consequences of sexual behaviours as predictors of shame.
Conclusions:
While women in the UK are rapidly shifting to a feminist way of thinking with or without technology, hypersexual disorder may often be misdiagnosed and misunderstood because of the lack of understanding and how it is conceptualised. The implications of these findings are discussed
Non‐Rayleigh Statistics of Ultrasonic Backscattered Echo from Tissues
The envelope of the backscattered signal from tissues can exhibit non‐Rayleigh statistics if the number density of scatterers is small or if the variations in the scattering cross sections are random. The K distribution which has been used extensively in radar, is introduced to model this non‐Rayleigh behavior. The generalized K distribution is extremely useful since it encompasses a wide range of distributions such as Rayleigh, Lognormal, and Rician. Computer simulations were conducted using a simple one‐dimensional discrete scatteringmodel to investigate the properties of the echo envelope. In addition to cases of low number densities, significant departures from Rayleigh statistics were seen as the scattering cross sections of the scatterers become random. The validity of this model was also tested using data from tissue mimicking phantoms. Results indicate that the density function of the envelope can be modeled by the K distribution and the parameters of the K distribution can provide information on the nature of the scattering region in terms of the number density of the scatterers as well as the scattering cross sections of the scatterers in the range cell. [Work was supported by NSF Grant No. BCS‐9207385.
Impactite and pseudotachylite from Roter Kamm Crater, Namibia
Pseudotachylite is known to occur in a variety of geologic settings including thrust belts (e.g., the Alps and the Himalayas) and impact craters such as Roter Kamm, Namibia. Controversy exists, however, as to whether pseudotachylite can be produced by shock brecciation as well as by tectonic frictional melting. Also open to debate is the question of whether pseudotachylites form by frictional fusion or by cataclasis. It was speculated that the pseudotachylite at Roter Kamm was formed by extensional settling and adjustment of basement blocks during 'late modification stage' of impact. The occurrence of pseudotachylite in association with rocks resembling quenched glass bombs and melt breccias in a relatively young crater of known impact origin offers a rare opportunity to compare features of these materials. Petrographic, x-ray diffraction, and electron microprobe analyses of the impactites and pseudotachylites are being employed to determine the modes of deformation and to assess the role of frictional melting and comminution of adjacent target rocks
Bell inequalities for continuous-variable correlations
We derive a new class of correlation Bell-type inequalities. The inequalities
are valid for any number of outcomes of two observables per each of n parties,
including continuous and unbounded observables. We show that there are no
first-moment correlation Bell inequalities for that scenario, but such
inequalities can be found if one considers at least second moments. The
derivation stems from a simple variance inequality by setting local commutators
to zero. We show that above a constant detector efficiency threshold, the
continuous variable Bell violation can survive even in the macroscopic limit of
large n. This method can be used to derive other well-known Bell inequalities,
shedding new light on the importance of non-commutativity for violations of
local realism.Comment: 4 pages, 1 figure. v2: New results on detector efficiencies and
macroscopic limit, new co-author, changed title and abstract, changed figure,
added journal reference and DO
Cervial cancer screening among HIV-positive women in rural Cambodia: a pilot programme
Mexico AIDS Conference 200
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