30 research outputs found
Common origin for Hercules-Aquila and Virgo Clouds in Gaia DR2
We use a sample of ~350 RR Lyrae stars with radial velocities and Gaia DR2
proper motions to study orbital properties of the Hercules-Aquila Cloud (HAC)
and Virgo Over-density (VOD). We demonstrate that both structures are dominated
by stars on highly eccentric orbits, with peri-centres around ~1 kpc and
apo-centres between 15 and 25 kpc from the Galactic centre. Given that the
stars in the HAC and the VOD occupy very similar regions in the space spanned
by integrals of motion, we conclude that these diffuse debris clouds are part
of the same accretion event. More precisely, these inner halo sub-structures
likely represent two complementary not-fully-mixed portions of an ancient
massive merger, also known as the "sausage" event.Comment: Submitted to MNRAS. Comments welcome
Preoperative assessment of patients with inflammatory processes in the maxillo-facial region: a minireview
The statistical data show the continuosly increasing number of patients with chronic diseases and this fact has a significant impact on the workload of all clinicians, including maxillofacial surgeons. On the other hand, inflammatory processes in the maxillofacial region are an important problem for maxillofacial surgeons due to the high number of patients who present with this diagnosis, but also because of the life-threatening complications that may occur. Besides the usual complications, a maxillofacial surgeon has to be aware of other comorbidities of the patients diagnosed with inflammatory processes, falling into the category of medically complex patients. The preoperative assessment main purpose is to identify those patients for whom the perioperative period may present an increased risk of morbidity and mortality, aside from the known complications already associated with inflammatory processes. This article aims to emphasize the importance of performing a complete and meticulous preoperative assessment of every single patient, even the apparently healthy ones, since the patient himself may be unaware of a comorbidity he might have. In order to facilitate this process, the use of standardized questionnaires for different groups of patients is encouraged for the prompt assessment of the patient’s condition. Another suggestion is the use of standardized protocols for emergency situations that may occur with these patients, including the use of tables with possible drug interactions between the medication used for the management of their chronic disease with the medication administered in the maxillofacial surgery unit
Odontogenic orbital diseases – management considerations
Summary. Odontogenic orbital abscess and cellulitis is rare but the well-documented complication of sinusitis and infections spread from
dental apical lesion. We report two cases of orbital abscess with periorbital cellulitis, with positive recent dental history and
spreading infection into the maxillary sinus. The patients have shown facial edema, ocular pain, exophthalmia. A surgical
intervention to drain the abscesses and a revision of the dental lesion and maxillary sinus were required.Introducere. Afectarea conținutului orbital și
țesuturilor paraorbitale este o afecțiune gravă, cu
evoluție fulminantă, care ar putea induce o infecție
cerebrală odontogenă cu prognostic vital nefavorabil.
Astfel diagnosticarea precoce și managementul
corect va fi influențat de fiecare specialist implicat
în conduita cazului dificil. Maladia are, de obicei, un
debut acut cu dureri oculare și cefalee, stare de rău,
febră, vertijuri, uneori cu simptome gastrice (vomă,
grețuri). Local va fi prezent edemul pronunțat cu hiperemie
și indurație (care uneori este confundat cu
un abces al pleoapei), exoflamie, dureri pronunțate
oculare și cefalee, scăderea mobilității oculare,
scăderea acuității vizuale în unele cazuri. Conform
datelor de literatură, afecțiunea survine în cazuri
rare prin ascensiunea infecției de la molarii maxilari
[1, 2]. Sunt 3 forme de ascensiune – hematogenă,
limfatică, extensie directă [1, 4]. Procesul odontogen cu exoftalmie este determinat de așezarea
anatomică și de microflora implicată în proces [3].
Anamneză stomatologică (intervenții sau afecțiuni
netratate dentare la nivel de maxilar superior) este
importantă în conduita acestor pacienți.
Prezentare de cazuri. Caz clinic 1: Pacienta
de 35 de ani, acuză edem și hiperemiea pleoapelor,
dureri oculare intense, cefalee, febră, stare de rău.
Cu o lună în urmă a suferit o intervenție dentară cu
extracția a doi dinți din maxilarul superior. Peste 5
zile – infectare, dureri, febră. Tratament chirurgical
la stomatolog – revizia plăgii infectate, drenare. Tratament
antibacterian. Peste 5- 7 zile simptomele se
repetă. Internată în Clinică Chirurgie maxilo- facială
– intervenție, drenare, tratament medicamentos.
Stare cu ameliorare. La 7 - 8 zile - agravarea stării,
simptomele se repetă. Consultată – DC – abces al
pleoapei – internată în secția oftalmologie pentru tratament chirurgical. Examinată în comun cu medicul
ORL, apoi internată în secția ORL IMPS SR Orhei,
cu clinica floridă de afecțiune inflamatorie acută
cu edem al pleoapelor, hiperemie, cefalee, stare
de rău. Tomografia computerizată – hiperecogenitate
în sinusurile paranazale, maxilare, sfenoidale,
exoftalmie și hiperecogenitate retrobulbară. Coordonare
cu secția ORL SCR, efectuat transferul – în
aceeași zi – tratament chirurgical cu deschiderea
sinusurilor paranazale – toate, revizie, drenare. Tratament
medicamentos. Stare cu ameliorare.
Caz clinic 2: Bărbat de 32 de ani, internat în
secția oftalmologie SR Orhei cu abces palpebral.
Efectuate incizii, aplicate drenuri. A doua zi – ameliorare.
La a 3-a zi – simptomele de inflamare reapar
– se face revizia plăgilor și radiografia sinusurilor.
Date de sinusită maxilară. Tratament chirurgical –
drenarea sinusului și sanare la stomatolog. Concluzii. Abcesul retrobulbar cu exoftalmie
și celulită este o afecțiune gravă care necesită o
atenție sporită pentru un diagnostic precoce și management
corect al afecțiunii
Spectroscopic Follow-Up of the Hercules Aquila Cloud
We designed a follow-up program to find the spectroscopic properties of the
Hercules-Aquila Cloud (HAC) and test scenarios for its formation. We measured
the radial velocities (RVs) of 45 RR Lyrae in the southern portion of the HAC
using the facilities at the MDM observatory, producing the first large sample
of velocities in the HAC. We found a double-peaked distribution in RVs, skewed
slightly to negative velocities. We compared both the morphology of HAC
projected onto the plane of the sky and the distribution of velocities in this
structure outlined by RR Lyrae and other tracer populations at different
distances to N-body simulations. We found that the behaviour is characteristic
of an old, well-mixed accretion event with small apo-galactic radius. We cannot
yet rule out other formation mechanisms for the HAC. However, if our
interpretation is correct, HAC represents just a small portion of a much larger
debris structure spread throughout the inner Galaxy whose distinct kinematic
structure should be apparent in RV studies along many lines of sight.Comment: accepted by MNRAS; 12 pages, 7 figure
The Ages of Galactic Bulge Stars with Realistic Uncertainties
Using modern isochrones with customized physics and carefully considered
statistical techniques, we recompute the age distribution for a sample of 91
micro-lensed dwarfs in the Galactic bulge presented by Bensby et al. (2017) and
do not produce an age distribution consistent with their results. In
particular, our analysis finds that only 15 of 91 stars have ages younger than
7 Gyr, compared to their finding of 42 young stars in the same sample. While we
do not find a constituency of very young stars, our results do suggest the
presence of an Gyr population at the highest metallicities, thus
contributing to long-standing debate about the age--metallicity distribution of
the Galactic bulge. We supplement this with attempts at independent age
determinations from two sources of photometry, BDBS and \textit{Gaia}, but find
that the imprecision of photometric measurements prevents reliable age and age
uncertainty determinations. Lastly, we present age uncertainties derived using
a first-order consideration of global modeling uncertainties in addition to
standard observational uncertainties. The theoretical uncertainties are based
on the known variance of free parameters in the 1D stellar evolution models
used to generate isochrones, and when included, result in age uncertainties of
-- Gyr for this spectroscopically well-constrained sample. These error
bars, which are roughly twice as large as typical literature values, constitute
realistic lower limits on the true age uncertainties.Comment: accepted to ApJ; revisions complet
Insights into the Galactic Bulge Chemodynamical Properties from Gaia Data Release 3
We explore the chemodynamical properties of the Galaxy in the azimuthal velocity V ϕ and metallicity [Fe/H] space using red giant stars from Gaia Data Release 3. The row-normalized V ϕ –[Fe/H] maps form a coherent sequence from the bulge to the outer disk, clearly revealing the thin/thick disk and the Splash. The metal-rich stars display bar-like kinematics, while the metal-poor stars show dispersion-dominated kinematics. The intermediate-metallicity population (−1 − 1 dex, with the Splash not participating in the bar formation and growth. Moreover, with a set of isolated evolving N-body disk simulations, we confirm that a nonrotating classical bulge can be spun up by the bar and develop cylindrical rotation, consistent with the observations for the metal-poor stars
Mapping the tilt of the Milky Way bulge velocity ellipsoids with ARGOS and Gaia DR2
Until the recent advent of Data Release 2 (DR2) and deep multi-object
spectroscopy, it has been difficult to obtain 6-D phase space information for
large numbers of stars beyond 4 kpc, in particular towards the Galactic centre,
where dust and crowding effects are significant. In this study we combine
line-of-sight velocities from the Abundances and Radial velocity Galactic
Origins Survey (ARGOS) spectroscopic survey with proper motions from
DR2, to obtain a sample of 7,000 red clump stars with 3-D velocities. We
perform a large scale stellar kinematics study of the Milky Way (MW) bulge to
characterize the bulge velocity ellipsoids. We measure the tilt of the
major-axis of the velocity ellipsoid in the radial-longitudinal velocity plane
in 20 fields across the bulge. The tilt or vertex deviation, is characteristic
of non-axisymmetric systems and a significant tilt is a robust indicator of
non-axisymmetry or bar presence. We compare the observations to the predicted
kinematics of an N-body boxy-bulge model formed from dynamical instabilities.
In the model, the values are strongly correlated with the angle
() between the bulge major-axis and the Sun-Galactic centre
line-of-sight. We use a maximum likelihood method to obtain an independent
measurement of , from bulge stellar kinematics alone. The most likely
value of given our model is . In the
Baade's window, the metal-rich stars display a larger vertex deviation () than the metal-poor stars () but we do not
detect significant metallicity trends in the other fields.Comment: 13 pages, 11 figure
The Blanco DECam Bulge Survey (BDBS) VIII: Chemo-kinematics in the southern Galactic bulge from 2.3 million red clump stars with Gaia DR3 proper motions
The Blanco DECam Bulge Survey (BDBS) provides near-ultraviolet to
near-infrared photometry for ~250 million unique stars. By combining BDBS
photometry with the latest Gaia astrometry, we characterize the chemo-dynamics
of red clump stars across the BDBS footprint, using an unprecedented sample
size and sky coverage. We construct a sample of ~2.3 million red clump giants
in the bulge with photometric metallicities, BDBS photometric distances, and
proper motions. We study the kinematics of the red clump stars as a function of
sky position and metallicity, by investigating proper motion rotation curves,
velocity dispersions, and proper motion correlations across the southern
Galactic bulge. We find that metal-poor red clump stars exhibit lower rotation
amplitudes, at ~29 km s kpc^{-1}. The peak of the angular velocity is
~39 km s^{-1} kpc^{-1} for [Fe/H] ~ -0.2 dex, exhibiting declining rotation at
higher [Fe/H]. The velocity dispersion is higher for metal-poor stars, while
metal-rich stars show a steeper gradient with Galactic latitude, with a maximum
dispersion at low latitudes along the bulge minor axis. Only metal-rich stars
([Fe/H] >~ -0.5 dex) show clear signatures of the bar in their kinematics,
while the metal-poor population exhibits isotropic motions with an axisymmetric
pattern around Galactic longitude l = 0. This work reports the largest sample
of bulge stars with distance, metallicity, and astrometry and shows clear
kinematic differences with metallicity. The global kinematics over the bulge
agrees with earlier studies. However, we see striking changes with increasing
metallicity and for the first time, see kinematic differences for stars with
[Fe/H]>-0.5, suggesting that the bar itself may have kinematics that depends on
metallicity.Comment: 12 pages, Accepted for publication in A&