163 research outputs found
Uncertainties in gas kinematics arising from stellar continuum modelling in integral field spectroscopy data: the case of NGC2906 observed with MUSE/VLT
We study how the use of several stellar subtraction methods and line fitting
approaches can affect the derivation of the main kinematic parameters (velocity
and velocity dispersion fields) of the ionized gas component. The target of
this work is the nearby galaxy NGC 2906, observed with the MUSE instrument at
Very Large Telescope. A sample of twelve spectra is selected from the inner
(nucleus) and outer (spiral arms) regions, characterized by different
ionization mechanisms. We compare three different methods to subtract the
stellar continuum (FIT3D, STARLIGHT and pPXF), combined with one of the
following stellar libraries: MILES, STELIB and GRANADA+MILES. The choice of the
stellar subtraction method is the most important ingredient affecting the
derivation of the gas kinematics, followed by the choice of the stellar library
and by the line fitting approach. In our data, typical uncertainties in the
observed wavelength and width of the H\alpha and [NII] lines are of the order
of _rms \sim 0.1\AA\ and _rms \sim 0.2\AA\ (\sim 5
and 10km/s, respectively). The results obtained from the [NII] line seem to be
slightly more robust, as it is less affected by stellar absorption than
H\alpha. All methods considered yield statistically consistent measurements
once a mean systemic contribution
\Delta\bar\lambda=\Delta\bar\sigma=0.2xDelta_{MUSE} is added in quadrature to
the line fitting errors, where \Delta_{MUSE} = 1.1\AA\ \sim 50 km/s denotes the
instrumental resolution of the MUSE spectra. Although the subtraction of the
stellar continuum is critical in order to recover line fluxes, any method
(including none) can be used in order to measure the gas kinematics, as long as
an additional component of 0.2 x Delta_MUSE is added to the error budget.Comment: 20 pages, 14 figure
The Molecular Biology of Vestibular Schwannomas and Its Association with Hearing Loss: A Review
Hearing loss is the most common symptom in patients with vestibular schwannoma (VS). In the past, compressive mechanisms caused by the tumoral mass and its growth have been regarded as the most likely causes of the hearing loss associated with VS. Interestingly, new evidence proposes molecular mechanisms as an explanation for such hearing loss. Among the molecular mechanisms proposed are methylation of TP73, negative expression of cyclin D1, expression of B7-H1, increased expression of the platelet-derived growth factor A, underexpression of PEX5L, RAD54B, and PSMAL, and overexpression of CEA. Many molecular mechanisms are involved in vestibular schwannoma development; we review some of these mechanisms with special emphasis on hearing loss associated with vestibular schwannoma
Universal determination of comagnetometer response to spin couplings
We propose and demonstrate a general method to calibrate the
frequency-dependent response of self-compensating noble-gas-alkali-metal
comagnetometers to arbitrary spin perturbations. This includes magnetic and
nonmagnetic perturbations like rotations and exotic spin interactions. The
method is based on a fit of the magnetic field response to an analytical model.
The frequency-dependent response of the comagnetometer to arbitrary spin
perturbations can be inferred using the fit parameters. We demonstrate the
effectiveness of this method by comparing the inferred rotation response to an
experimental measurement of the rotation response. Our results show that
experiments relying on zero-frequency calibration of the comagnetometer
response can over- or under-estimate the comagnetometer sensitivity by orders
of magnitude over a wide frequency range. Moreover, this discrepancy
accumulates over time as operational parameters tend to drift during
comagnetometer operation. The demonstrated calibration protocol enables
accurate prediction and control of comagnetometer sensitivity to, for example,
ultralight bosonic dark-matter fields coupling to electron or nuclear spins as
well as accurate monitoring and control of the relevant system parameters
Inhibition of the PP2A activity by the histone chaperone ANP32B is long-range allosterically regulated by respiratory cytochrome c
Repair of injured DNA relies on nucleosome dismantling by histone chaperones and de-phosphorylation events carried out by Protein Phosphatase 2A (PP2A). Typical histone chaperones are the Acidic leucine-rich Nuclear Phosphoprotein 32 family (ANP32) members, e.g. ANP32A, which is also a well-known PP2A inhibitor (a.k.a. I1PP2A). Here we report the novel interaction between the endogenous family member B—so-called ANP32B—and endogenous cytochrome c in cells undergoing camptothecin-induced DNA damage. Soon after DNA lesions but prior to caspase cascade activation, the hemeprotein translocates to the nucleus to target the Low Complexity Acidic Region (LCAR) of ANP32B; in a similar way, our group recently reported that the hemeprotein targets the acidic domain of SET/Template Activating Factor-Iß (SET/TAF-Iß), which is another histone chaperone and PP2A inhibitor (a.k.a. I2PP2A). The nucleosome assembly activity of ANP32B is indeed unaffected by cytochrome c binding. Like ANP32A, ANP32B inhibits PP2A activity and is thus herein referred to as I3PP2A. Our data demonstrates that ANP32B-dependent inhibition of PP2A is regulated by respiratory cytochrome c, which induces long-distance allosteric changes in the structured N-terminal domain of ANP32B upon binding to the C-terminal LCAR. In agreement with the reported role of PP2A in the DNA damage response, we propose a model wherein cytochrome c is translocated from the mitochondria into the nucleus upon DNA damage to modulate PP2A activity via its interaction with ANP32B. © 2021 The Author(s
Thermally Pulsing Asymptotic Giant Branch Star Models and Globular Cluster Planetary Nebulae I: The Model
Thermally pulsing asymptotic giant branch models of globular cluster stars
are calculated using a synthetic model with the goal of reproducing the
chemical composition, core masses and other observational parameters of the
four known globular cluster planetary nebulae as well as roughly matching the
overall cluster properties. The evolution of stars with an enhanced helium
abundance () and blue stragglers are modeled. New pre-thermally pulsing
asymptotic giant branch mass-losses for red giant branch and early asymptotic
giant branch stars are calculated from the Padova stellar evolution models
\citep{berta,bertb}. The new mass-losses are calculated to get the relative
differences in mass-losses due to enhanced helium abundances.
The global properties of the globular cluster planetary nebula are reproduced
with these models. The metallicity, mass of the central star, overall
metallicities, helium abundance and the nebular mass are matched to the
observational values. Globular cluster planetary nebulae JaFu 1 and JaFu 2 are
reproduced {\it by assuming progenitor stars} with masses near the typical main
sequence turn-offs of globular clusters and with enhanced helium abundances
very similar to the enhancements inferred from fitting isochrones to globular
cluster colour-magnitude diagrams. The globular cluster PN GJJC-1 can be
roughly fit by a progenitor star with very extreme helium enhancement
() near the turn-off producing a central star with the same mass
as inferred by observations and a very low nebular mass. The abundances and
core mass of planetary nebula Ps 1 and its central star (K648) are reproduced
by a blue straggler model. However, it turned out to be impossible to reproduce
its nebular mass and it is concluded some kind of binary scenario may be needed
to explain K648.Comment: 14 pages, 8 figures, accepted for publication in MNRA
Television Series Use in Teaching and Learning Professional Ethics in Communication
The work presented here is an exploratory and descriptive study under a
qualitative approach. It purposes was to show the use of television series, as a
means of teaching and learning professional ethics in communication
undergraduate students. Among the results we found two direct areas of impact:
teaching and learning. In the case of teaching, the professor shows an innovative
practice and she realized different ways to improve it as a continuous way to
advance her teaching. In the case of learning, the use of television series
promoted the interest of the students and a significant learning. However, the
most important finding of this study is that the teaching experience has
contributed in the educational process of communicators specifically in ethical
thinking
Hepatic Sarcoidosis Presenting as Portal Hypertension and Liver Cirrhosis: Case Report and Review of the Literature
Systemic sarcoidosis is a disease of unknown etiology, with the liver being the third most commonly affected organ. Most cases of hepatic sarcoidosis are not clinically apparent, but a few can progress to liver cirrhosis, portal hypertension and ultimately liver failure. The diagnosis of hepatic sarcoidosis is difficult, considering that no single laboratory test or radiographic finding can definitively diagnose this systemic disease. Diagnosis of hepatic sarcoidosis relies heavily on histopathologic evaluation of two or more organs, a diagnostic modality that is invasive and may not be applicable to all patients. The treatment of hepatic sarcoidosis is challenging, with no large randomized controlled trials done to date. Physicians must be aware of the complications of hepatic sarcoidosis, and must include the same in the differential diagnosis of liver cirrhosis. We present a case of hepatic sarcoidosis complicated by portal hypertension and liver cirrhosis
Height and timing of growth spurt during puberty in young people living with vertically acquired HIV in Europe and Thailand.
OBJECTIVE: The aim of this study was to describe growth during puberty in young people with vertically acquired HIV. DESIGN: Pooled data from 12 paediatric HIV cohorts in Europe and Thailand. METHODS: One thousand and ninety-four children initiating a nonnucleoside reverse transcriptase inhibitor or boosted protease inhibitor based regimen aged 1-10 years were included. Super Imposition by Translation And Rotation (SITAR) models described growth from age 8 years using three parameters (average height, timing and shape of the growth spurt), dependent on age and height-for-age z-score (HAZ) (WHO references) at antiretroviral therapy (ART) initiation. Multivariate regression explored characteristics associated with these three parameters. RESULTS: At ART initiation, median age and HAZ was 6.4 [interquartile range (IQR): 2.8, 9.0] years and -1.2 (IQR: -2.3 to -0.2), respectively. Median follow-up was 9.1 (IQR: 6.9, 11.4) years. In girls, older age and lower HAZ at ART initiation were independently associated with a growth spurt which occurred 0.41 (95% confidence interval 0.20-0.62) years later in children starting ART age 6 to 10 years compared with 1 to 2 years and 1.50 (1.21-1.78) years later in those starting with HAZ less than -3 compared with HAZ at least -1. Later growth spurts in girls resulted in continued height growth into later adolescence. In boys starting ART with HAZ less than -1, growth spurts were later in children starting ART in the oldest age group, but for HAZ at least -1, there was no association with age. Girls and boys who initiated ART with HAZ at least -1 maintained a similar height to the WHO reference mean. CONCLUSION: Stunting at ART initiation was associated with later growth spurts in girls. Children with HAZ at least -1 at ART initiation grew in height at the level expected in HIV negative children of a comparable age
Relationships between body growth indices and environmental factors on the reproductive cycle of the Gymnodactylus geckoides Spix, 1825 (Squamata, Gymnophthalmidae) in Northeast Brazil
In this study, we analyzed the energy and reproductive cycles of female and male Gymnodactylus geckoides in the Caatinga area of northeast Brazil. We investigated whether these proxies of body condition, such as reproductive cells maturation and cellular structures changed in response to variation in abiotic and biotic factors (i.e., humidity, temperature, seasonality, body temperature, growing rate and gonad volume), using individuals stored under scientific conditions collected between September 2018 and December 2021. The condition factor showed an isometric growth pattern in the population studied. Meanwhile, the lipid, hepatic, and gonad factors correlated with body growth and showed monthly and seasonal variations, as well as reproductive cell maturation and cellular structure morphology. The cycles displayed constant replacement of energy reserves and mature reproductive cells, indicating constant and acyclic reproduction in G. geckoides. Energy reserves appear to be used for many reproductive activities, including meeting, gestation, and egg laying that occur at different frequencies during different periods in the dry and rainy seasons. Therefore, the reproductive cycle is likely to be strongly controlled by biotic factors, which are modeled using abiotic factors and environmental conditions (environmental patterns which proportionate greater resource availability). Our study is the first to investigate energy cycles and reproductive strategies in G. geckoides. It has shown that this species stores greater amounts of energy during the rainy season and then depletes these reserves during the dry period, since the rainy season correspond to the increase in energy consumption, mainly because of gestation and egg laying.Asociación Herpetológica Argentin
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