1,231 research outputs found
A method of open cluster membership determination
A new method for the determination of open cluster membership based on a
cumulative effect is proposed. In the field of a plate the relative x and y
coordinate positions of each star with respect to all the other stars are
added. The procedure is carried out for two epochs t_1 and t_2 separately, then
one sum is subtracted from another. For a field star the differences in its
relative coordinate positions of two epochs will be accumulated. For a cluster
star, on the contrary, the changes in relative positions of cluster members at
t_1 and t_2 will be very small. On the histogram of sums the cluster stars will
gather to the left of the diagram, while the field stars will form a tail to
the right. The procedure allows us to efficiently discriminate one group from
another. The greater the distance between t_1 and t_2 and the more cluster
stars present, the greater is the effect. The accumulation method does not
require reference stars, determination of centroids and modelling the
distribution of field stars, necessary in traditional methods. By the proposed
method 240 open clusters have been processed, including stars up to m<13. The
membership probabilities have been calculated and compared to those obtained by
the most commonly used Vasilevskis-Sanders method. The similarity of the
results acquired the two different approaches is satisfactory for the majority
of clusters.Comment: 10 pages, 5 figure
Memberships and CM Diagrams of the Open Cluster NGC 7243
The results of astrometric and photometric investigations of the open cluster
NGC 7243 are presented. Proper motions of 2165 stars with root-mean-square
error of 1.1 mas/yr were obtained by means of PDS scanning of astrometric
plates covering the time interval of 97 years. A total of 211 cluster members
down to V=15.5 mag have been identified. V and B magnitudes have been
determined for 2118 and 2110 stars respectively. Estimations of mass (348Mo < M
< 522Mo), age (t=2.5x10^8 yr), distance (r=698 pc) and reddening (E(B-V)=0.24)
of the cluster NGC 7243 have been made.Comment: 24 pages, 15 figures. Submitted to Astronomy and Astrophysic
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Non-hemagglutinating flaviviruses: molecular mechanisms for the emergence of new strains via adaptation to European ticks
Tick-borne encephalitis virus (TBEV) causes human epidemics across Eurasia. Clinical manifestations range from inapparent infections and fevers to fatal encephalitis but the factors that determine disease severity are currently undefined. TBEV is characteristically a hemagglutinating (HA) virus; the ability to agglutinate erythrocytes tentatively reflects virion receptor/fusion activity. However, for the past few years many atypical HA-deficient strains have been isolated from patients and also from the natural European host tick, Ixodes persulcatus. By analysing the sequences of HA-deficient strains we have identified 3 unique amino acid substitutions (D67G, E122G or D277A) in the envelope protein, each of which increases the net charge and hydrophobicity of the virion surface. Therefore, we genetically engineered virus mutants each containing one of these 3 substitutions; they all exhibited HA-deficiency. Unexpectedly, each genetically modified non-HA virus demonstrated increased TBEV reproduction in feeding Ixodes ricinus, not the recognised tick host for these strains. Moreover, virus transmission efficiency between infected and uninfected ticks co-feeding on mice was also intensified by each substitution. Retrospectively, the mutation D67G was identified in viruses isolated from patients with encephalitis. We propose that the emergence of atypical Siberian HA-deficient TBEV strains in Europe is linked to their molecular adaptation to local ticks. This process appears to be driven by the selection of single mutations that change the virion surface thus enhancing receptor/fusion function essential for TBEV entry into the unfamiliar tick species. As the consequence of this adaptive mutagenesis, some of these mutations also appear to enhance the ability of TBEV to cross the human blood-brain barrier, a likely explanation for fatal encephalitis. Future research will reveal if these emerging Siberian TBEV strains continue to disperse westwards across Europe by adaptation to the indigenous tick species and if they are associated with severe forms of TBE
Comparative assessment of modern parameters of glycemic control in children with type 1 diabetes after switching to fast-acting insulin aspart using Flash Glucose Monitoring in real clinical practice
BACKGROUND: Postprandial hyperglycaemia contributes significantly to the lack of glycaemic control in patients with type 1 diabetes mellitus (DM1). At least a quarter of patients forget to inject insulin before meals once a week, and more than 40% of them inject bolus insulin immediately before meals, which does not correspond to the pharmacokinetic effects of ultrashort insulins and determines the need to use insulins with better imitations of physiological insulin secretion.AIM: To assess the effect of fast acting insulin aspart (FIAsp) on the current parameters of glycaemic control in children with DM1 after switching from insulin Asp (iAsp) using continuous glucose monitoring.MATERIALS AND METHODS: A multicenter observational 12-week prospective open-label uncontrolled comparative study was initiated. A group of insufficiently controlled patients were identified (n = 48) including a group on multiple insulin injections therapy (MII) (insulin degludec and IAsp) and a group on continuous subcutaneous insulin infusion (CSII) of iAsp. Three 14-day flash glucose monitoring (FMG) were performed: before transferring patients to FiAsp and after 2 and 12 weeks of the transfer. Key endpoints: HbA1c after 2 and 12 weeks on FiAsp relative to baseline, analysis of 5 FMG target glucose ranges, presented as an ambulatory glycemic profile. Additional indicators: dynamics of insulin daily dose, frequency of glucose self- monitoring, the number of severe hypoglycemia, adverse events that occurred during treatment.RESULTS: 2 weeks after the transfer from IAsp to FIAsp, TIR increased in the entire group of patients: from 53% [44.3; 66.5] to 57% [47.4; 71.0] (p-value = 0.010) and TAR decreased from 38% [24.8; 50.2] to 30.5% [22.0; 45, 0] (p-value = 0.0124). Maintaining and increase time spent in the target glucose ranges during a 12-week observation period, in parallel with a significant decrease in hypoglycemic episodes <3.9 mmol / L per week, on FIAsp therapy naturally leads to an improvement in diabetes control: a decrease in HbA1c from 8.15% up to 7.75% (p-value = 0.0224), more pronounced in the group of patients on CSII — from 7.9% to 7.5% (p-value = 0.028).CONCLUSION: Switching from IAsp to BDIAsp in routine clinical practice in the MII and CSII regimen in children and adolescents with type 1 diabetes allows achieving better glycemic control compared to the previous generation prandial insulin analog Iasp. The better diabetes control is associated with an increase or a trend towards an increase in TIR and a decrease or a trend towards a decrease in TAR and TBR, as well as a significant decrease in episodes of hypoglycemia
Results of observation of a family case of thyrotropic hormone resistance syndrome
The purpose of the study was to evaluate the development of children with congenital subclinical hypothyroidism and not receiving hormone replacement therapy in order to select therapeutic tactics.Цель исследования – оценить развитие детей, имеющих врожденный субклинический гипотиреоз и не получающих заместительную гормональную терапию, для выбора терапевтической тактики
Measurement of the cross-section and charge asymmetry of bosons produced in proton-proton collisions at TeV with the ATLAS detector
This paper presents measurements of the and cross-sections and the associated charge asymmetry as a
function of the absolute pseudorapidity of the decay muon. The data were
collected in proton--proton collisions at a centre-of-mass energy of 8 TeV with
the ATLAS experiment at the LHC and correspond to a total integrated luminosity
of 20.2~\mbox{fb^{-1}}. The precision of the cross-section measurements
varies between 0.8% to 1.5% as a function of the pseudorapidity, excluding the
1.9% uncertainty on the integrated luminosity. The charge asymmetry is measured
with an uncertainty between 0.002 and 0.003. The results are compared with
predictions based on next-to-next-to-leading-order calculations with various
parton distribution functions and have the sensitivity to discriminate between
them.Comment: 38 pages in total, author list starting page 22, 5 figures, 4 tables,
submitted to EPJC. All figures including auxiliary figures are available at
https://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/PAPERS/STDM-2017-13
Search for chargino-neutralino production with mass splittings near the electroweak scale in three-lepton final states in √s=13 TeV pp collisions with the ATLAS detector
A search for supersymmetry through the pair production of electroweakinos with mass splittings near the electroweak scale and decaying via on-shell W and Z bosons is presented for a three-lepton final state. The analyzed proton-proton collision data taken at a center-of-mass energy of √s=13 TeV were collected between 2015 and 2018 by the ATLAS experiment at the Large Hadron Collider, corresponding to an integrated luminosity of 139 fb−1. A search, emulating the recursive jigsaw reconstruction technique with easily reproducible laboratory-frame variables, is performed. The two excesses observed in the 2015–2016 data recursive jigsaw analysis in the low-mass three-lepton phase space are reproduced. Results with the full data set are in agreement with the Standard Model expectations. They are interpreted to set exclusion limits at the 95% confidence level on simplified models of chargino-neutralino pair production for masses up to 345 GeV
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