2,459 research outputs found
The Transitive Groups of Degree Fourteen and Fifteen
AbstractAll transitive groups of degree fourteen and fifteen up to conjugacy in the symmetric group are listed. The computations, carried out with Cayley, involve the use of subgroup lattices of quotient groups, preimages of the subgroups of the quotient, low index subgroups, systems of imprimitivity, and testing conjugacy of subgroups. Our results for degree fourteen agree with previous results of Miller in 1897, but the results for degree fifteen are new
The Lick-Carnegie Exoplanet Survey: A Saturn-Mass Planet in the Habitable Zone of the Nearby M4V Star HIP 57050
Precision radial velocities from Keck/HIRES reveal a Saturn-mass planet
orbiting the nearby M4V star HIP 57050. The planet has a minimum mass of 0.3
Jupiter-mass, an orbital period of 41.4 days, and an orbital eccentricity of
0.31. V-band photometry reveals a clear stellar rotation signature of the host
star with a period of 98 days, well separated from the period of the radial
velocity variations and reinforcing a Keplerian origin for the observed
velocity variations. The orbital period of this planet corresponds to an orbit
in the habitable zone of HIP 57050, with an expected planetary temperature of
approximately 230 K. The star has a metallicity of [Fe/H] = 0.32+/-0.06 dex, of
order twice solar and among the highest metallicity stars in the immediate
solar neighborhood. This newly discovered planet provides further support that
the well-known planet-metallicity correlation for F, G, and K stars also
extends down into the M-dwarf regime. The a priori geometric probability for
transits of this planet is only about 1%. However, the expected eclipse depth
is ~7%, considerably larger than that yet observed for any transiting planet.
Though long on the odds, such a transit is worth pursuing as it would allow for
high quality studies of the atmosphere via transmission spectroscopy with HST.
At the expected planetary effective temperature, the atmosphere may contain
water clouds.Comment: 20 pages, 5 figures, 3 tables, to appear in the May 20 issue of ApJ
Integrin-linked kinase can facilitate syncytialization and hormonal differentiation of the human trophoblast-derived BeWo cell line
<p>Abstract</p> <p>Background</p> <p>In the fusion pathway of trophoblast differentiation, stem villous cytotrophoblast cells proliferate and daughter cells differentiate and fuse with existing syncytiotrophoblast to maintain the multi-nucleated layer. Integrin-linked kinase (ILK) is highly expressed in 1st and 2nd trimester villous cytotrophoblast cells, yet barely detectable in syncytiotrophoblast, thus we examined the potential role of ILK in aiding trophoblast fusion.</p> <p>Methods</p> <p>The temporal/spatial expression and activity of ILK were determined in BeWo cells undergoing syncytialization by immunoblot and immunofluorescence analyses. BeWo cells were also transfected with pEGFP expression vectors containing wildtype or two mutant ILK cDNA constructs. The incidence of cell fusion in transfected cells grown under syncytialization conditions was then scored by the presence or absence of E-cadherin immunostaining. Beta-hCG expression in transfected cells, a marker of syncytiotrophoblast hormonal differentiation, was also similarly assessed.</p> <p>Results</p> <p>ILK catalytic activity increased and ILK began to increasingly localize to BeWo cell nuclei during syncytialization in correlation with increased pAkt and Snail protein expression. Syncytialization was also significantly elevated (p < 0.05) in BeWo cells expressing constitutively active (ca)-ILK vs cells containing empty vector or dn-ILK. Furthermore, cytoplasmic Beta-hCG expression markedly increased (p < 0.05) in cells expressing wt- and ca-ILK.</p> <p>Conclusion</p> <p>ILK-facilitated syncytialization is dependent, at least in part, on ILK catalytic activity while hormonal differentiation appears dependent on both ILK-associated protein interactions and catalytic activity. This study demonstrates that ILK plays a novel role in BeWo syncytialization and differentiation, perhaps through an ILK-Akt-Snail pathway, and implicates ILK in the same process in villous cytotrophoblasts in vivo.</p
Kitamura Electrophilic Fluorination Using HF as a Source of Fluorine
This review article focused on the innovative procedure for electrophilic fluorination using HF and in situ generation of the required electrophilic species derived from hypervalent iodine compounds. The areas of synthetic application of this approach include fluorination of 1,3-dicarbonyl compounds, aryl-alkyl ketones, styrene derivatives, α,β-unsaturated ketones and alcohols, homoallyl amine and homoallyl alcohol derivatives, 3-butenoic acids and alkynes.This research was funded by the National Natural Science Foundation of China (No. 21761132021), and IKERBASQUE, Basque Foundation for Science
Advances in the Development of Trifluoromethoxylation Reagents
This review provides a short summary of the traditional methods for synthesis of CF3-O-containing compounds, followed by a critical overview of known trifluoromethoxylating reagents, focusing on their preparation, synthetic generality and limitations
The Latest FDA-Approved Pharmaceuticals Containing Fragments of Tailor-Made Amino Acids and Fluorine
Nowadays, the selective introduction of fluorine into bioactive compounds is a mature strategy in the design of drugs allowing to increase efficiency, biological half-life and bio-absorption. On the other hand, amino acids (AAs) represent one of the most ubiquitious classes of naturally occurring organic compounds, which are found in over 40% of newly marked small-molecule pharmaceutical drugs and medical formulations. The primary goal of this work is to underscore two major trends in the design of modern pharmaceuticals. The first is dealing with the unique structural characteristics provided by the structure of amino acids featuring an abundance of functionality and the presence of a stereogenic center, all of which bodes well for the successful development of targeted bioactivity. The second is related to fine-tuning the desired activity and pharmacokinetics by selective introduction of fluorine. Historically, both trends were developed separately as innovative and prolific approaches in modern drug design. However, in recent decades, these approaches are clearly converging leading to an ever-increasing number of newly approved pharmaceuticals containing both structural features of amino acids and fluorine.This work was funded by the National Natural Science Foundation of China (No. 21761132021), and IKERBASQUE, Basque Foundation for Science. The financial support from the University of the Basque Country UPV/EHU (UFIQOSYC11/22), Basque Government (GVgrant IT1236-19), and Ministerio de Ciencia e Innovación (grant PID2019-109633GBC21) for. A. L. are also acknowledged
A Uniformly Derived Catalogue of Exoplanets from Radial Velocities
A new catalogue of extrasolar planets is presented by re-analysing a
selection of published radial velocity data sets using EXOFIT (Balan & Lahav
2009). All objects are treated on an equal footing within a Bayesian framework,
to give orbital parameters for 94 exoplanetary systems. Model selection
(between one- and two-planet solutions) is then performed, using both a visual
flagging method and a standard chi-square analysis, with agreement between the
two methods for 99% of the systems considered. The catalogue is to be made
available online, and this 'proof of concept' study may be maintained and
extended in the future to incorporate all systems with publicly available
radial velocity data, as well as transit and microlensing data.Comment: 16 pages, 6 figures, 6 table
Physical profile of Air Force Special Warfare trainees
International Journal of Exercise Science 16(4): 924-931, 2023. Physical fitness testing in the military is commonly used to assess whether service members are physically capable of performing the diverse physical tasks that may be required for their job. Body composition can influence an individual’s ability to physically perform. This study aimed to analyze the general physical profile of U.S. Air Force (USAF) special warfare candidates by assessing body composition results and physical assessment scores collected over the past four years. Male candidates (n = 1036) were 18.2 years to 39.5 years of age (M = 23.5, SD = 3.9) and weighed 78.8 kg (SD = 8.3) with a BMI of 25.0 (SD = 2.0) at 11.8% body fat (SD = 3.3) as measured using bioelectrical impedance. Body composition and fitness scores were similar to those noted in U.S. Navy special warfare candidates as well as individuals in other elite tactical units. These results highlight the normative body composition profile of individuals assessing for advanced military career fields
Five Planets Orbiting 55 Cancri
We report 18 years of Doppler shift measurements of a nearby star, 55 Cancri,
that exhibit strong evidence for five orbiting planets. The four previously
reported planets are strongly confirmed here. A fifth planet is presented, with
an apparent orbital period of 260 days, placing it 0.78 AU from the star in the
large empty zone between two other planets. The velocity wobble amplitude of
4.9 \ms implies a minimum planet mass \msini = 45.7 \mearthe. The orbital
eccentricity is consistent with a circular orbit, but modest eccentricity
solutions give similar \chisq fits. All five planets reside in low eccentricity
orbits, four having eccentricities under 0.1. The outermost planet orbits 5.8
AU from the star and has a minimum mass, \msini = 3.8 \mjupe, making it more
massive than the inner four planets combined. Its orbital distance is the
largest for an exoplanet with a well defined orbit. The innermost planet has a
semi-major axis of only 0.038 AU and has a minimum mass, \msinie, of only 10.8
\mearthe, one of the lowest mass exoplanets known. The five known planets
within 6 AU define a {\em minimum mass protoplanetary nebula} to compare with
the classical minimum mass solar nebula. Numerical N-body simulations show this
system of five planets to be dynamically stable and show that the planets with
periods of 14.65 and 44.3 d are not in a mean-motion resonance. Millimagnitude
photometry during 11 years reveals no brightness variations at any of the
radial velocity periods, providing support for their interpretation as
planetary.Comment: accepted to Ap
- …