132 research outputs found
Isotropic and anisotropic pointing models
This paper describes an alternative approach for generating pointing models
for telescopes equipped with serial kinematics, esp. equatorial or alt-az
mounts. Our model construction does not exploit any assumption for the
underlying physical constraints of the mount, however, one can assign various
effects to the respective components of the equations. In order to recover the
pointing model parameters, classical linear least squares fitting procedures
can be applied. This parameterization also lacks any kind of parametric
singularity. We demonstrate the efficiency of this type of model on real
measurements with meter-class telescopes where the results provide a root mean
square accuracy of 1.5-2 arcseconds.Comment: Accepted for publication in Exp. Astro
Comparative study of Gymnocephalus cernuus (Linnaeus, 1758) and G. baloni Holcik & Hensel, 1974 (Pisces, Percidae)
In the comparative study of Gymnocephalus cernuus and G. baloni we searched for differences in growth, habitat and feeding between the two species in support of their distinctness. significant differences were found in both habitat and feeding, whereas growth was more or less similar. G. baloni is bound to hiding places located in flowing water. In vegetative periods it occurs solitary and in generative in pairs. G. cernuus lives in shoals in the whole season, occuring mostly in the open, still parts of waters near to the bottom. The food of the two ruffe species mostly consists of the characteristic macroinvertebrates of their habitat. The body pattern, the number of opecular spines and the cut on the membrane between AI and AII were found to be the most useful characters in identification
A nemzetbiztonsági szolgálatok rendszere: Nemzetközi gyakorlat a nemzetbiztonsági rendszer kialakĂtására
A szerzĹ‘k a tanulmányukban 32 ország 122 nemzetbiztonsági szolgálatát megvizsgálva rendszereztĂ©k a nemzetbiztonsági rendszer összetevĹ‘it, valamint megállapĂtották, hogy milyen nemzetbiztonsági szolgálatok működnek a nemzetközi közössĂ©gen belĂĽl. Ezt követĹ‘en – több szempont alapján – csoportosĂtották a nemzetbiztonsági szolgálatokat, valamint megvizsgálták a szolgálatok felĂĽgyeletĂ©nek Ă©s irányĂtásának rendszerĂ©t is. MegállapĂtották, hogy a szolgálatok számában az elmĂşlt kĂ©t Ă©vtizedben kettĹ‘s tendencia figyelhetĹ‘ meg, ami egyrĂ©szrĹ‘l Ăşjabb szolgálatok lĂ©trehozásában, mĂg másrĂ©szrĹ‘l a meglĂ©vĹ‘ szolgálatok összevonásában nyilvánul meg. A tanulmány vĂ©gĂ©n a nemzetközi kitekintĂ©s alapján megállapĂtották, hogy Magyarország jelenlegi nemzetbiztonsági rendszere megfelel a nemzetközi mintáknak Ă©s trendeknek
1H, 15N backbone assignment and comparative analysis of the wild type and G12C, G12D, G12V mutants of K-Ras bound to GDP at physiological pH
K-Ras protein is a membrane-bound small GTPase acting as a molecular switch. It plays a key role in many signal transduction pathways regulating cell proliferation, differentiation, survival, etc. It alternates between its GTP-bound active and the GDP-bound inactive conformers regulated by guanine nucleotide exchange factors and GTPase activating proteins. Its most frequent oncogenic mutants are G12C, G12D, and G12V that have impaired GTPase activity, thus induce malignant tumors. Here we report the resonance assignment of the backbone 1H and 15N nuclei of K-Ras wildtype, G12C, G12D and G12V proteins’ catalytic G domain (1–169 residues) in GDP-bound state, and 13C of backbone and side chains of G12C mutant at physiological pH 7.4. Triple resonance data were used to get secondary structure information and backbone dynamics of G12C, the best-known drug target among K-Ras mutants. Simultaneous investigation of G12C, G12D and G12V mutants, along with the wild type form at the very same conditions allowed us to perform a comprehensive analysis based on the combined chemical shifts to reveal the effect of mutation at G12 position on structure. Intriguingly, the G12C and G12V mutants found to be structurally very similar at the three most important regions of K-Ras (P-loop, Switch-I, Switch-II), while the G12D mutant significantly differs at P-loop and Switch-II from the wildtype as well as G12C and G12V mutants. However, in Switch-I it hardly deviates from the wildtype protein
Hexapod Design For All-Sky Sidereal Tracking
In this paper we describe a hexapod-based telescope mount system intended to
provide sidereal tracking for the Fly's Eye Camera project -- an upcoming
moderate, 21"/pixel resolution all-sky survey. By exploiting such a kind of
meter-sized telescope mount, we get a device which is both capable of
compensating for the apparent rotation of the celestial sphere and the same
design can be used independently from the actual geographical location. Our
construction is the sole currently operating hexapod telescope mount performing
dedicated optical imaging survey with a sub-arcsecond tracking precision.Comment: Accepted for publication in PASP, 10 page
Deletion of poly(ADP?ribose) polymerase-1 changes the composition of the microbiome in the gut
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