149 research outputs found
Spatially Resolved Kinematics of an Ultra-Compact Dwarf Galaxy
We present the internal kinematics of UCD3, the brightest known ultra-compact
dwarf galaxy (UCD) in the Fornax cluster, making this the first UCD with
spatially resolved spectroscopy. Our study is based on seeing-limited
observations obtained with the ARGUS Integral Field Unit of the VLT/FLAMES
spectrograph under excellent seeing conditions (0.5 - 0.67 arcsec FWHM). The
velocity field of UCD3 shows the signature of weak rotation, comparable to that
found in massive globular clusters. Its velocity dispersion profile is fully
consistent with an isotropic velocity distribution and the assumption that mass
follows the light distribution obtained from Hubble Space Telescope imaging. In
particular, there is no evidence for the presence of an extended dark matter
halo contributing a significant (>~33 per cent within R < 200 pc) mass
fraction, nor for a central black hole more massive than ~5 per cent of the
UCD's mass. While this result does not exclude a galaxian origin for UCD3, we
conclude that its internal kinematics are fully consistent with it being a
massive star cluster.Comment: 5 pages, 3 figures; accepted for publication in MNRAS Letter
Chemodynamics of Compact Stellar Systems in NGC 5128: How similar are Globular Clusters, Ultra-Compact Dwarfs, and Dwarf Galaxies?
Velocity dispersion measurements are presented for luminous GCs in NGC 5128
derived from high-res. UVES spectra. The measurements are made with the pPXF
code that parametrically recovers line-of-sight velocity dispersions. Combining
the measured velocity dispersions with surface photometry and structural
parameter data from HST enables both dynamical masses and M/L ratios to be
derived. The fundamental plane relations of these clusters are investigated in
order to fill the apparent gap between the relations of Local Group GCs and
more massive early-type galaxies. It is found that the properties of these
massive stellar systems match those of nuclear clusters in dwarf elliptical
galaxies and UCDs better than those of Local Group GCs, and that all objects
share similarly old (>8 Gyr) ages, suggesting a possible link between the
formation and evolution of dE,Ns, UCDs and massive GCs. We find a very steep
correlation between dynamical (M/L) ratio and dynamical mass of the form
(M/L)_dyn ~ M_dyn^(0.24+/-0.02) above M_dyn = 2x10^6 Msol. Formation scenarios
are investigated with a chemical abundance analysis using absorption line
strengths calibrated to the Lick/IDS index system. The results lend support to
two scenarios contained within a single general formation scheme. Old, massive,
super-solar [alpha/Fe] systems are formed on short (<100 Myr) timescales
through the merging of single-collapse GCs which themselves are formed within
single, giant molecular clouds. More intermediate- and old-aged (~3-10 Gyr),
solar- to sub-solar [alpha/Fe] systems are formed on much longer (~Gyr)
timescales through the stripping of dE,Ns in the 10^13-10^15 Msol potential
wells of massive galaxies and galaxy clusters.Comment: 12 pages (ApJ style) with 11 figures and 7 tables, accepted for
publication in Ap
Hematological parameters of rheumatoid arthritis patients undergoing total hip replacement
Abstract. Background Patients with rheumatoid arthritis (RA) and baseline anemia may have an increased risk of complications after total hip replacement
(THR). Inflammation in RA is the main factor manifesting anaemia, neutropenia, thrombocytosis and eosinophilia. The changes in blood components are
important for the outcomes of major orthopaedic surgery. The purpose was to identify hematological parameters in RA patients undergoing THR and
assess the effect on intraoperative blood loss. Material and methods Outcomes of 44 THR patients treated for grade III degenerative coxarthrosis (n = 21,
OA group) and RA coxarthrosis (n = 23, RA group) in Ekaterinburg regional hospital № 1 between 2018 and 2019 were reviewed. The patients' age ranged
from 41 to 70 years. Clinical, radiological, laboratory examinations, computed tomography and statistical analysis were used for the study. Cell counting
was produced with the Sysmex XT-4000i automated hematology system. Statistical analysis was performed using the tools of Statistica software. Nonparametric
Mann-Whitney test was used to compare cell counts between the groups. The Spearman Rank correlation was used to analyse the correlation
between the the cell counts in the groups. For calculations, a significance level of р < 0.05 was adopted. Results There were no significant differences in the
preoperative white blood cell (WBC), neutrophil, lymphocyte, monocyte, eosinophil counts between RA and OA groups. The RA group showed an evident
decrease in red blood cell (RBC) count and haemoglobin level as compared to OA group. The RA group demonstrated the higher platelet count with mean
platelet volume (MPV) being significantly lower than that in the OA group. WBC count, neutrophils, in particular, was shown to increase with lymphocyte,
RBC, platelet count and hemoglobin, plateletcrit levels decreased at 24 hours postoperatively. There were no significant differences in WBC and RBC
counts in the groups postoperatively. The differences in the MPV were leveled up in the groups with the platelet count being higher in the RA group as
compared to the OA group. Conclusions Hematological parameters of RA patients who had undergone specific preoperative preparation were not shown
to be associated with greater blood loss during hip replacement surgery. The leukocyte count leveled up in the preoperative and early postoperative periods
can be indicative of the absence of a significant effect of RA on the postoperative inflammation
NGC 7468: a galaxy with an inner polar disk
We present our spectroscopic observations of the galaxy NGC 7468 performed at
the 6-m Special Astrophysical Observatory telescope using the UAGS long-slit
spectrograph, the multipupil fiber spectrograph MPFS, and the scanning
Fabry-Perot interferometer (IFP). We found no significant deviations from the
circular rotation of the galactic disk in the velocity field in the regions of
brightness excess along the major axis of the galaxy (the putative polar ring).
Thus, these features are either tidal structures or weakly developed spiral
arms. However, we detected a gaseous disk at the center of the galaxy whose
rotation plane is almost perpendicular to the plane of the galactic disk. The
central collision of NGC 7468 with a gas-rich dwarf galaxy and their subsequent
merging seem to be responsible for the formation of this disk.Comment: 8 pages, 6 figures, accepted in Astronomy Letters, 2004, vol 30., N
9, p. 58
Treatment of osteoporosis: recommendations and reality
То achieve optimal results of treatment osteoporosis, not only effective medication, but also patients' adherence to treatment is required. Aim: to assess rates and factors of patients' adherence to prescribed treatment of osteoporosis. Methods: the study included 340 residents of the Sverdlovsk Region, Russia, who had previously been diagnosed and consulted regarding osteoporosis. Letters with questionnaires and envelopes for the answers were sent to all patients at least in 3 months after the treatment had been prescribed. Questionnaires included questions about treatment, risk factors, knowledge about osteoporosis. Reply rate was 62,5% (182 persons). Replies of these 182 patients were processed. Results: 7 (3,8%) patients did not begin recommended treatment at all. By the date of inquiry in 15 (8,2%) persons the treatment was terminated, while 160 (87,9%) patients continued with their treatment. Recommended pathogenic treatment of osteoporosis was taken by 116 (63,7%) patients, but only 72 (39,6%) of them received it on a regular basis. Factors of better patients' adherence to pathogenetic treatment of osteoporosis were: disability (OR 2,3:95% Cl 1,22 — 4,32), long duration of osteoporosis (OR 2,54:95% Cl 1,23 — 5,25), fracture history (OR 2,06:95% Cl 1,11 — 3,81) and back pain and height loss due to vertebral fractures (OR 4,68; 95% Cl 2,34 — 9,39). Conclusion: Patients' adherence to pharmacotherapy of osteoporosis is low in general clinical practice. Only 39,6% patients received pathogenetic medication on a regular basis. Fracture history, back pain and height loss are associated with better adherence to treatment Thus, patients with complicated osteoporosis are more adherent to treatment than those with preclinical stage of osteoporosis.Для достижения оптимальных результатов терапии больных остеопорозом (ОП) важно помимо доказанной эффективности препаратов соблюдение приверженности пациентов лечению. Целью данной работы являлась оценка приверженности больных ОП лечению и факторы, влияющие на нее. Материал и методы. В исследование включены пациенты Свердловской области с установленным диагнозом ОП и рекомендованным лечением, при условии, что после консультации и назначения лечения прошло, по крайней мере, 3 месяца. Всем проконсультированным пациентам была проведена почтовая рассылка анкет с вопросами о проводимом лечении ОП, о факторах риска ОП и его клинических проявлениях, а также с вопросами, оценивающими знания об ОП. Всего было разослано 340 писем. Отклик выборки составил 62,5%. В обработку включены ответы 182 чел. Результаты Из 182 опрошенных пациентов рекомендованное лечение не начали только 7 чел. (3,8%). 15 пациентов (8,2%) прекратили лечение. 160 чел. (87,9%) продолжали лечение на момент опроса. Препараты патогенетического действия принимали 116 чел. (63,7%), но только 72 чел. (39,6%) лечились препаратами патогенетического действия регулярно. На прием препаратов патогенетического действия влияли: наличие группы инвалидности (ОШ = 2,3: 95% ДИ=1,22 — 4,32, продолжительность заболевания после постановки диагноза ОШ=2,54; 95% ДИ=1,23 — 5,25, наличие переломов костей в анамнезе при низком уровне травмы, 0ш=2,06; 95% ДИ=1,11 — 3,81, а также клинические признаки переломов позвонков (боль в спине и снижение роста) ОШ=4,68; 95% ДИ=2,34 — 9,39. Таким образом, приверженность пациентов с ОП лечению низкая, только 39,6% пациентов принимают регулярно препараты патогенетического действия. Пациенты с переломами костей в анамнезе при низком уровне травмы и с клиническими симптомами переломов позвонков более привержены лечению, чем пациенты с доклинической стадией ОП
Educational program for osteoporosis patients
Aim: to assess effectiveness of different educational interventions for patients with osteoporosis. Methods: Eighty patients with osteoporosis (95.0% were women) were randomized into the experimental group (n=40) and control group (n=40). The mean age was 62,5±9,0 SD. The patients of experimental group participated in education sessions contained four lessons with interactive methods. The patients of control group got leaflets. Baseline variables were not significantly different between groups. All patients had previously been consulted regarding osteoporosis. Participants were assessed at baseline, 3 months, 6 months and 12 months. The results showed statistically significant increases for knowledge about osteoporosis in the experimental group (63,6%, 64,6%, 65,8% correct answers at 3, 6 and 12 months) compared with control (51,0%, 52,3%, 53,7% correspondingly), p<0,05. Calcium intake was more than 90% in both groups during the study. Recommended pathogenic treatment of osteoporosis was taken by 81,6%, 83,8%, 79,3% patients of the experimental group and 60%, 50%, 54,5% patients of the control group at 3 ,6 and 12 months, p<0,05. Adherence to pathogenetic treatment of osteoporosis was higher in experimental group. Consumption of milk foods was increased at 3 month in both groups and exercises were increased only in experimental group (from 27,5 min. to 112,5 min. in the week), p<0,05. Conclusion: education program for patients with osteoporosis increase adherence to treatment. Education sessions with interactive methods in small groups are more effective, than leaflets.Целью данной работы являлась оценка эффективности различных форм образовательных программ для пациентов с ОП. Материалы и методы: в исследование включено 80 пациентов (95,0% женщин) с первичным ОП. Ср. возраст 62,5±9,0 лет. Все пациенты были случайным образом распределены на две группы. Пациенты основной группы (40 чел.), проходили обучение в небольших группах в течение 4 занятий с использованием интерактивных методов. Контрольная группа (40 чел.) получила информацию в виде брошюры. Исходно группы были сопоставимы по всем изучаемым параметрам. Всем пациентам даны рекомендации по лечению ОП. Оценка проводилась через 3, 6 и 12 мес. Результаты: знания по вопросам ОП были лучше у пациентов основной группы (63.6%, 64,6%, 65,8% правильных ответов через 3,6 и 12 месяцев) по сравнению с контролем (51,0%, 52,3%, 53,7% соответственно), р<0,05. Препараты кальция на протяжении всего исследования принимали более 90% пациентов обеих групп. Число пациентов, принимающих препараты патогенетического действия, в основной группе было больше (81,6%. 83,8%, 79,3% через 3, 6 и 12 мес.) по сравнению с контролем (60%, 50%, 54,5% соответственно), р<0,05. Приверженность приему данных препаратов также была выше в основной группе. Потребление кальция с пищей достоверно возросло у пациентов обеих групп ко второму визиту, а время выполнения упражнений увеличилось только в основной группе (с 27,5 мин. до 112,5 мин. В неделю), р<0,05. Таким образом, образовательные программы по ОП увеличивают приверженность лечению. Обучение пациентов на занятиях в небольших группах с использованием интерактивных методов более эффективно, чем получение информации в виде брошюры
Testing Newtonian Gravity with AAOmega: Mass-to-Light Profiles of Four Globular Clusters
Testing Newtonian gravity in the weak-acceleration regime is vital to our
understanding of the nature of the gravitational interaction. It has recently
been claimed that the velocity dispersion profiles of several globular clusters
flatten out at large radii, reminiscent of galaxy rotation curves, even though
globular clusters are thought to contain little or no dark matter. We
investigate this claim, using AAOmega observations of four globular clusters,
namely M22, M30, M53 and M68. M30, one such cluster that has had this claim
made for its velocity dispersion, was included for comparison with previous
studies. We find no statistically significant flattening of the velocity
dispersion at large radii for any of our target clusters and therefore we infer
the observed dynamics do not require that globular clusters are dark matter
dominated, or a modification of gravity. Furthermore, by applying a simple
dynamical model we determine the radial mass-to-light profiles for each
cluster. The isothermal rotations of each cluster are also measured, with M22
exhibiting clear rotation, M68 possible rotation and M30 and M53 lacking any
rotation, within the uncertainties.Comment: 7 pages, 4 figures and two tables. Accepted by MNRA
A search for massive UCDs in the Centaurus Galaxy Cluster
We recently initiated a search for ultra-compact dwarf galaxies (UCDs) in the
Centaurus galaxy cluster (Mieske et al. 2007), resulting in the discovery of 27
compact objects with -12.2<M_V<-10.9 mag. Our overall survey completeness was
15-20% within 120 kpc projected clustercentric distance. In order to better
constrain the luminosity distribution of the brightest UCDs in Centaurus, we
continue our search by substantially improving our survey completeness
specifically in the regime M_V<-12 mag (V_0<21.3 mag). Using VIMOS at the VLT,
we obtain low-resolution spectra of 400 compact objects with 19.3<V_0<21.3 mag
(-14<M_V<-12 mag at the Centaurus distance) in the central 25' of the Centaurus
cluster, which corresponds to a projected radius of ~150 kpc. Our survey yields
complete area coverage within ~120 kpc. For 94% of the sources included in the
masks we successfully measure a redshift. Due to incompleteness in the slit
assignment, our final completeness in the area surveyed is 52%. Among our
targets we find three new UCDs in the magnitude range -12.2<M_V<-12 mag, hence
at the faint limit of our survey. One of them is covered by archival HST WFPC2
imaging, yielding a size estimate of r_h <= 8-9 pc. At 95% confidence we can
reject the hypothesis that in the area surveyed there are more than 2 massive
UCDs with M_V<-12.2 mag and r_eff <=70 pc. Our survey hence confirms the
extreme rareness of massive UCDs. We find that the radial distributions of
Centaurus and Fornax UCDs with respect to their host clusters' centers agree
within the 2 sigma level.Comment: 9 pages, 7 figures, accepted as Research Note for A&
Merging of Low-Mass Systems and the Origin of the Fundamental Plane
We present a new set of dissipationless N-body simulations to examine the
feasibility of creating bright ellipticals (following the Kormendy relation) by
hierarchically merging present-day early-type dwarf galaxies, and to study how
the encounter parameters affect the location of the end-product in the
plane. We investigate the merging of one-component
galaxies of both equal and different masses, the merging of two-component
galaxy models to explore the effect of dark halos on the final galaxy
characteristics, and the merging of ultracompact dwarf galaxies. We find that
the increase of with is attributable to an increase in the
initial orbital energy. The merger remnants shift down in the plane and fail to reach the KR. Thus, the KR is not reproducable by
mergers of dwarf early-type systems, rendering untenable the theory that
present-day dwarfs are responsible for even a small fraction of the present-day
ellipticals, unless a considerable amount of dissipation is invoked. However,
we do find that present-day dwarfs can be formed by the merger of ultra-compact
dwarfs.Comment: 10 pages, 8 figures. Accepted for publication in MNRA
Two formation channels of UCDs in Hickson Compact Groups
The formation of ultra-compact dwarf galaxies (UCDs) is believed to be
interaction driven, and UCDs are abundant in the cores of galaxy clusters,
environments that mark the end-point of galaxy evolution. Nothing is known
about the properties of UCDs in compact groups of galaxies, environments where
most of galaxy evolution and interaction is believed to occur and where UCDs in
intermediate state of evolution may be expected. The main goal of this study is
to detect and characterize, for the first time, the UCD population of compact
groups. For that, 2 groups in different evolutionary stages, HCG 22 and HCG 90,
were targeted with VLT/FORS2/MXU. We detect 16 and 5 objects belonging to HCG
22 and HCG 90, respectively, covering the magnitude range -10.0 > M_R > -11.5
mag. Their colours are consistent with old ages covering a broad range in
metallicities. Photometric mass estimates put 4 objects in HCG 90 and 9 in HCG
22 in the mass range of UCDs (>2x10^6 M_Sun) for an assumed age of 12 Gyr.
These UCDs are on average 2-3 times larger than typical Galactic GCs, covering
a range of 2 >~ r_h >~ 21 pc. The UCDs in HCG 22 are more concentrated around
the central galaxy than in HCG 90, at the 99% confidence level. They cover a
broad range in [alpha/Fe] abundances from sub- to super-solar. The spectra of 3
UCDs show tentative evidence for intermediate age stellar populations. We
calculate the specific frequency (S_N) of UCDs for both groups, finding that
HCG 22 has about three times higher S_N than HCG 90. The ensemble properties of
the detected UCDs supports 2 co-existing formation channels: a star cluster
origin and an origin as tidally stripped dwarf nuclei. Our results imply that
the UCDs detected in both groups do not, in their majority, originate from
relatively recent galaxy interactions. Most of the detected UCDs have likely
been brought into the group with their host galaxies.[abridged]Comment: Accepted for publication at A&A, 17 pages, 9 figures + 2 additional
figure
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