75 research outputs found
The first near infrared detection of XTE J1118+480 in quiescence
We report the first quiescent detection of KV UMa, the optical counterpart of
XTE J1118+480 at near infrared. The observed magnitudes and colours are
consistent with a K7-M0 V star, at the distance 1.4 +/- 0.2 kpc. The light
curve shows strong orbital modulation with possible contamination from a
superhump detected in the quiescent optical light curves.Comment: To appear in MNRAS Letters; 4 pages, 3 figure
Herschel PACS and SPIRE observations of blazar PKS 1510-089: a case for two blazar zones
We present the results of observations of blazar PKS 1510-089 with the
Herschel Space Observatory PACS and SPIRE instruments, together with
multiwavelength data from Fermi/LAT, Swift, SMARTS and SMA. The source was
found in a quiet state, and its far-infrared spectrum is consistent with a
power-law with a spectral index of alpha ~ 0.7. Our Herschel observations were
preceded by two 'orphan' gamma-ray flares. The near-infrared data reveal the
high-energy cut-off in the main synchrotron component, which cannot be
associated with the main gamma-ray component in a one-zone leptonic model. This
is because in such a model the luminosity ratio of the External-Compton and
synchrotron components is tightly related to the frequency ratio of these
components, and in this particular case an unrealistically high energy density
of the external radiation would be implied. Therefore, we consider a
well-constrained two-zone blazar model to interpret the entire dataset. In this
framework, the observed infrared emission is associated with the synchrotron
component produced in the hot-dust region at the supra-pc scale, while the
gamma-ray emission is associated with the External-Compton component produced
in the broad-line region at the sub-pc scale. In addition, the optical/UV
emission is associated with the accretion disk thermal emission, with the
accretion disk corona likely contributing to the X-ray emission.Comment: 13 pages, 8 figures, 7 tables; accepted for publication in the
Astrophysical Journa
Teaching MBA Students Teamwork And Team Leadership Skills: An Empirical Evaluation Of A Classroom Educational Program
A comprehensive educational program for teaching behavioral teamwork and team leadership skills was rigorously evaluated with 148 MBA students enrolled at an urban regional campus of a Midwestern public university. Major program components included (1) videotaped student teams in leaderless group discussion (LGD) exercises at the course beginning and end, (2) behavioral assessment of student teamwork and team leadership in the LGD’s, (3) peer and instructor performance feedback and coaching after each LGD, (4) informational modules on teamwork and team leadership, and (5) multiple opportunities (classroom and field) to practice teamwork and team leadership skills. Prominent findings indicated (1) a statistically significant increase in overall teamwork and overall team leadership scores of, respectively, 14% and 8%, (2) no demographic differences in student improvements as a function of sex, age, or race/ethnicity, and (3) very favorable student responses to end-of-course questions concerning teamwork and team leadership skills improvement, self-confidence, and attitudes
Tracing colliding winds in the UV line orbital variability of gamma-ray binaries
Gamma-ray binaries emit most of their radiated power beyond ~10 MeV. The
non-thermal emission is thought to arise from the interaction of the
relativistic wind of a rotation-powered pulsar with the stellar wind of its
massive (O or Be) companion star. A powerful pulsar creates an extended cavity,
filled with relativistic electrons, in the radiatively-driven wind of the
massive star. As a result, the observed P Cyg profiles of UV resonant lines
from the stellar wind should be different from those of single massive stars.
We propose to use UV emission lines to detect and constrain the colliding wind
region in gamma-ray binaries. We compute the expected orbital variability of P
Cyg profiles depending upon the interaction geometry (set by the ratio of
momentum fluxes from the winds) and the line-of-sight to the system. We predict
little or no variability for the case of LS 5039 and PSR B1259-63, in agreement
with currently available HST observations of LS 5039. However, variability
between superior and inferior conjunction is expected in the case of LS I+61
303.Comment: Accepted for publication in MNRA
A classification of the X-ray and radio states of Cyg X-3 and their long-term correlations
We present a detailed classification of the X-ray states of Cyg X-3 based on
the spectral shape and a new classification of the radio states based on the
long-term correlated behaviour of the radio and soft X-ray light curves. We
find a sequence of correlations, starting with a positive correlation between
the radio and soft X-ray fluxes in the hard spectral state, changing to a
negative one at the transition to soft spectral states. The temporal evolution
can be in either direction on that sequence, unless the source goes into a very
weak radio state, from which it can return only following a major radio flare.
The flare decline is via relatively bright radio states, which results in a
hysteresis loop on the flux-flux diagram. We also study the hard X-ray light
curve, and find its overall anticorrelation with the soft X-rays. During major
radio flares, the radio flux responds exponentially to the level of a hard
X-ray high-energy tail. We also specify the detailed correspondence between the
radio states and the X-ray spectral states. We compare our results to those of
black-hole and neutron-star binaries. Except for the effect of strong
absorption and the energy of the high-energy break in the hard state, the X-ray
spectral states of Cyg X-3 closely correspond to the canonical X-ray states of
black-hole binaries. Also, the radio/X-ray correlation closely corresponds to
that found in black-hole binaries, but it significantly differs from that in
neutron-star binaries. Overall, our results strongly support the presence of a
black hole in Cyg X-3.Comment: MNRAS, in pres
Differences in the prognosis of HPV16-positive patients with squamous cell carcinoma of head and neck according to viral load and expression of P16
Purpose To evaluate the impact of HPV16 load (VL-the
number of virus genome copies per cell) and P16 expression
on prognosis of patients with squamous cell carcinomas
(SCCs) of head and neck (HN).
Materials and methods HPV16 presence was assessed in
the group of 109 patients with HNSCCs by quantitative polymerase
chain reaction (qPCR). VL (assessed by qPCR) and
P16 expression (evaluated by immunohistochemistry) were
analysed only in the subgroup of HPV16-positive tumours.
These features were correlated with 5-year overall survival
(OS) and disease-free survival (DFS).
Results HPV16 infection was found in 36 tumours
(33.0%). Virus-positive patients had better OS and DFS
than those without infection (P = 0.041 and 0.005). Among
HPV16-positive HNSCCs, 18 (50.0%) had higher VL
(median value > 6764.3 copies/cell) and 25 (73.5%) P16 over expression. The significant differences in OS and
DFS (P = 0.008 and 0.004) were noticed according to VL,
wherein 100% DFS was found for patients with higher
VL. According to P16 expression, significant difference
was found only for OS (P = 0.020). In multivariate analysis,
VL (P = 0.045; HR = 2.795; CI 0.121-1.060) and the
level of smoking (P = 0.023, HR = 2.253; CI 1.124-4.514)
were independent factors affecting DFS of HPV16-positive
patients.
Conclusion On the basis of viral load, it is possible to
differentiate prognosis of patients with HPV16-positive
HNSCCs. In this subgroup, viral load has stronger prognostic
potential than P16 expression
The effects of prostaglandin E-2 treatment on the secretory function of mare corpus luteum depends on the site of application : an in vivo study
Research Areas: Veterinary SciencesWe examined the effect of prostaglandin (PG) E2 on the secretory function of equine corpus luteum (CL), according to the application site: intra-CL injection vs. an intrauterine (intra-U) administration. Moreover, the effect of intra-CL injection vs. intra-U administration of both luteotropic factors: PGE2 and human chorionic gonadotropin (hCG) as a positive control, on CL function was additionally compared. Mares were assigned to the groups (n = 6 per group): (1) an intra-CL saline injection (control); (2) an intra-CL injection of PGE2 (5 mg/ml); (3) an intra-CL injection of hCG (1,500 IU/ml); (4) an intra-U saline administration (control); (5) an intra-U administration of PGE2 (5 mg/5 ml); (6) an intra-U administration of hCG (1,500 IU/5 ml). Progesterone (P4) and PGE2 concentrations were measured in blood plasma samples collected at −2, −1, and 0 (pre-treatment), and at 1, 2, 3, 4, 6, 8, 10, 12, and 24 h after treatments. Moreover, effects of different doses of PGE2 application on the concentration of total PGF2α (PGF2α and its main metabolite 13,14-dihydro-15-keto-prostaglandin F2α– PGFM) was determined. The time point of PGE2, hCG, or saline administration was defined as hour “0” of the experiment. An intra-CL injection of PGE2 increased P4 and PGE2 concentrations between 3 and 4 h or at 3 and 12 h, respectively (p < 0.05). While intra-U administration of PGE2 elevated P4 concentrations between 8 and 24 h, PGE2 was upregulated at 1 h and between 3 and 4 h (p < 0.05). An intra-CL injection of hCG increased P4 concentrations at 1, 6, and 12 h (p < 0.05), while its intra-U administration enhanced P4 and PGE2 concentrations between 1 and 12 h or at 3 h and between 6 and 10 h, respectively (p < 0.05). An application of PGE2, dependently on the dose, supports equine CL function, regardless of the application site, consequently leading to differences in both P4 and PGE2 concentrations in blood plasmainfo:eu-repo/semantics/publishedVersio
The inhibitory effect of noscapine on the in vitro cathepsin G-induced collagen expression in equine endometrium
Research Areas: Life Sciences & Biomedicine ; MicrobiologyABSTRACT - Cathepsin G (CAT) is a protease released by neutrophils when forming neutrophil extracellular traps that was already associated with inducing type I collagen (COL1) in equine endometrium
in vitro. Endometrosis is a fibrotic condition mainly characterized by COL1 deposition in the equine
endometrium. The objective was to evaluate if noscapine (an alkaloid for cough treatment with
anti-neoplastic and anti-fibrotic properties) would reduce COL1A2 transcription (evaluated by qPCR)
and COL1 protein relative abundance (evaluated by western blot) induced by CAT in equine endometrial explants from follicular and mid-luteal phases treated for 24 or 48 h. The explants treated with
CAT increased COL1 expression. Noscapine decreased COL1A2 transcription at both estrous cycle
phases, but COL1 relative protein only at the follicular phase, both induced by CAT. Additionally,
the noscapine anti-fibrotic action was found to be more effective in the follicular phase. The CAT
treatment caused more fibrosis at the longest period of treatment, while noscapine acted better at the
shortest time of treatment. Our results showed that noscapine could act as an anti-fibrotic drug in
equine endometrosis by inhibiting CAT in vitro. Noscapine offers a new promising therapeutic tool
for treating fibrosis as a single non-selective agent to be considered in the future.info:eu-repo/semantics/publishedVersio
Analysis of LCT-13910 genotypes and bone mineral density in ancient skeletal materials
The relation of LCT-13910 genotypes and bone mineral density (BMD) has been the subject of modern-day human population studies, giving inconsistent results. In the present study we analyze for the first time a relation of LCT-13910 genotypes and BMD in historical skeletal individuals. Ancient population might be a model for testing this association due to elimination of non-natural factors affecting bone density. Among 22 medieval individuals from Sanok churchyard (South-Eastern Poland; dated from XIV to XVII c. AD) we identified 4 individuals with osteoporosis (mean BMD = 0.468 g/cm2, SD = 0.090), 10 individuals with osteopenia (mean BMD = 0.531 g/cm2, SD = 0.066) and 8 individuals with normal BMD values (mean BMD = 0,642 g/cm2, SD = 0.060). Analyses of BMD and LCT-13910 genotypes revealed that mean BMD was the highest (0.583 g/cm2, SD = 0.065) in the individuals with lactose tolerance genotypes (TT and CT). We also found possible association of lower BMD at the radius and CC genotypes due to higher but not statistically significant frequency of osteoporosis in the lactose intolerant group (p = 0.60). Statistically significant correlation was found between BMD and females aged 20-35 years, with tendency to reduce BMD with age (p = 0.02)
Myeloperoxidase inhibition decreases the expression of collagen and metallopeptidase in mare endometria under in vitro conditions
Research Areas: Agriculture ; Veterinary Sciences ; ZoologyABSTRACT - Neutrophils can originate neutrophil extracellular traps (NETs). Myeloperoxidase (MPO) is
a peroxidase found in NETs associated to equine endometrosis and can be inhibited by 4-aminobenzoic
acid hydrazide (ABAH). Metallopeptidases (MMPs) participate in extracellular matrix stability and
fibrosis development. The objectives of this in vitro work were to investigate, in explants of mare’s
endometrium, (i) the ABAH capacity to inhibit MPO-induced collagen type I (COL1) expression;
and (ii) the action of MPO and ABAH on the expression and gelatinolytic activity of MMP-2/-9.
Explants retrieved from the endometrium of mares in follicular or mid-luteal phases were treated
with MPO, ABAH, or their combination, for 24 or 48 h. The qPCR analysis measured the transcription
of COL1A2, MMP2, and MMP9. Western blot and zymography were performed to evaluate COL1
protein relative abundance and gelatinolytic activity of MMP-2/-9, respectively. Myeloperoxidase
elevated COL1 relative protein abundance at both treatment times in follicular phase (p < 0.05). The
capacity of ABAH to inhibit MPO-induced COL1 was detected in follicular phase at 48 h (p < 0.05).
The gelatinolytic activity of activated MMP-2 augmented in mid-luteal phase at 24 h after MPO
treatment, but it was reduced with MPO+ABAH treatment. The activity of MMP-9 active form
augmented in MPO-treated explants. However, this effect was inhibited by ABAH in the follicular
phase at 48 h (p < 0.05). By inhibiting the pro-fibrotic effects of MPO, it might be possible to reduce
the development of endometrosis. Metallopeptidase-2 might be involved in an acute response to
MPO in the mid-luteal phase, while MMP-9 might be implicated in a prolonged exposition to MPO
in the follicular phase.info:eu-repo/semantics/publishedVersio
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