Abstract
STUDY QUESTION
How do transgender men experience fertility preservation (FP) by cryopreservation of oocytes?
SUMMARY ANSWER
The procedures required prior to oocyte cryopreservation, such as ...hormonal ovarian stimulation and transvaginal ultrasound (TVS), have a negative impact on gender dysphoria as they are closely linked to the men's female assigned sex at birth, which is incompatible with their current status.
WHAT IS KNOWN ALREADY
Transgender persons often have high dissatisfaction with assigned sex-specific body features, such as the genital organs and androgen/oestrogen-responsive features. Thus, undergoing FP that requires genital-specific examinations, aimed at obtaining oocytes to cryopreserve, could be distressing. As no previous studies have investigated transgender men's experiences of FP involving cryopreservation of oocytes, little is known about their experience of the procedures.
STUDY DESIGN, SIZE, DURATION
This is a prospective study among adult transgender men referred for FP between March 2014 and December 2015. Individual in-depth qualitative interviews were conducted shortly after FP treatment. The interviews lasted between 62 and 111 min (mean 81 min) and were digitally recorded and transcribed verbatim.
PARTICIPANTS/MATERIALS, SETTING, METHODS
Participants were recruited on their first visit to the assisted reproduction clinic for reproductive counseling. There were 15 men, scheduled for FP, who chose to participate in the study (age 19–35); none had given birth and eight had a partner. Data were analyzed by thematic content analysis.
MAIN RESULTS AND THE ROLE OF CHANCE
The analysis resulted in three main categories: the journey to FP, reactions to the FP proceedings and strategies for coping. The referral for FP was an important part of the assessment and diagnosis and sometimes lined with frustrating waits and doubts. The reaction to the FP proceedings revealed that the genital examinations and the physical changes associated with discontinuation of testosterone or hormonal stimulation treatment triggered gender incongruence and dysphoria. However, for some, the negative expectations were not met. The participants used several coping strategies in order to manage the procedure, such as focusing on their reasons for undergoing FP, reaching out to friends and family for support and the cognitive approaches of not hating their body or using non-gendered names for their body parts. The results demonstrate the importance of contextual sensitivity during FP procedures.
LIMITATIONS, REASONS FOR CAUTION
The authors have strived to be reflective about their pre-understanding of the phenomenon. The majority of the participants resided in large urban areas; it is possible that transgender men living in rural areas have different experiences.
WIDER IMPLICATIONS OF THE FINDINGS
As the results are based on qualitative data from 15 transgender men, the results cannot readily be generalized to larger populations. However, the results are suggested to be applicable to other transgender men who want to undergo FP by cryopreservation of oocytes. The results show that transgender men's experience of FP places may elicit gender incongruence and gender dysphoria. However, health care personnel can alleviate distress by using a gender-neutral language and the preferred pronoun. Also, reassuringly, the men also have coping strategies of how to handle the situation. This knowledge is important to ensure adequate professional support for patients with gender dysphoria during FP.
STUDY FUNDING/COMPETING INTEREST(S)
Swedish Society of Medicine, Stockholm County Council and Karolinska Institutet (to K.A.R.-W.).
TRIAL REGISTRATION NUMBER
N/A.
ABSTRACT The disk mass is among the most important input parameter for every planet formation model to determine the number and masses of the planets that can form. We present an ALMA 887 m survey of ...the disk population around objects from ∼2 to 0.03 M in the nearby ∼2 Myr old Chamaeleon I star-forming region. We detect thermal dust emission from 66 out of 93 disks, spatially resolve 34 of them, and identify two disks with large dust cavities of about 45 au in radius. Assuming isothermal and optically thin emission, we convert the 887 m flux densities into dust disk masses, hereafter Mdust. We find that the relation is steeper than linear and of the form Mdust ∝ (M*)1.3-1.9, where the range in the power-law index reflects two extremes of the possible relation between the average dust temperature and stellar luminosity. By reanalyzing all millimeter data available for nearby regions in a self-consistent way, we show that the 1-3 Myr old regions of Taurus, Lupus, and Chamaeleon I share the same relation, while the 10 Myr old Upper Sco association has a steeper relation. Theoretical models of grain growth, drift, and fragmentation reproduce this trend and suggest that disks are in the fragmentation-limited regime. In this regime millimeter grains will be located closer in around lower-mass stars, a prediction that can be tested with deeper and higher spatial resolution ALMA observations.
Millimeter observations of CO gas in planetesimal belts show a high detection rate around A stars, but few detections for later type stars. We present the first CO detection in a planetesimal belt ...around an M star, TWA 7. The optically thin CO (J = 3-2) emission is colocated with previously identified dust emission from the belt, and the emission velocity structure is consistent with Keplerian rotation around the central star. The detected CO is not well shielded against photodissociation, and must thus be continuously replenished by gas release from exocomets within the belt. We analyze in detail the process of exocometary gas release and destruction around young M dwarfs and how this process compares to earlier type stars. Taking these differences into account, we find that CO generation through exocometary gas release naturally explains the increasing CO detection rates with stellar luminosity, mostly because the CO production rate from the collisional cascade is directly proportional to stellar luminosity. More luminous stars will therefore on average host more massive (and hence more easily detectable) exocometary CO disks, leading to the higher detection rates observed. The current CO detection rates are consistent with a ubiquitous release of exocometary gas in planetesimal belts, independent of spectral type.
Context.
Scattered-light images reveal that a significant fraction of debris discs consist of a bright ring beyond which extends a wide halo. This halo is expected and should be made of small grains ...collisionally produced in the ring of parent bodies (PBs) and pushed on high-eccentricity orbits by radiation pressure. It has been shown that, under several simplifying assumptions, the surface brightness (SB) of this halo should radially decrease as
r
−3.5
in scattered light
Aims.
We aim to revisit the halo phenomenon and focus on two unexplored issues: (1) how the unavoidable presence of small unbound grains, non-isotropic scattering phase functions (SPFs), and finite instrument resolution affect scattered-light SB profiles, and (2) how the halo phenomenon manifests itself at longer wavelengths in thermal emission, both on resolved images and on system-integrated spectral energy distributions (SEDs).
Methods.
We use a collisional evolution code to estimate the size-dependent spatial distribution of grains in a belt+halo system at steady state. We use the GRaTeR radiative-transfer code to derive synthetic images in scattered light and thermal emission, as well as SEDs.
Results.
We find that unbound grains account for a significant fraction of the halo’s luminosity in scattered light, and can significantly flatten the SB radial profile for the densest and brightest discs. Because halos are strongly size-segregated with radial distance, realistic size-dependent SPFs also have an effect, resulting here again in shallower SB profiles. For edge-on discs, non-resolving the vertical profile can also significantly flatten the projected SB profile. We show that roughly half of the observationally derived halo profiles found in the literature are compatible with our new results, and that roughly half of the remaining systems are probably shaped by additional processes (planets, stellar companions, etc.). We also propose that, in future observational studies, the characteristics of the PB belts and the halos should be fitted separately. In thermal emission, we find that wide halos should remain detectable up to the far-infrared (far-IR) and that, with the exception of the ~8–15 µm domain, the halo accounts for more than half of the system’s total flux up to
λ ~
80–90 µm. The contribution from the halo strongly decreases in the submm to mm but still represents a few percent of the system’s luminosity at
λ
~ 1 mm. For unresolved systems, the presence of a halo can also affect the determination of the radius of the disc from its SED.
Stereotactic body radiation therapy of thoracic tumors close to the central airways implies risk of severe toxicity. We report a prospective multicenter phase 2 trial for tumors located less than or ...equal to 1 cm from the proximal bronchial tree with primary end point of local control and secondary end point of toxicity.
Stereotactic body radiation therapy with 7 Gy × 8 was prescribed to the 67% isodose encompassing the planning target volume. The patients were stratified to group A (tumors ≤ 1 cm from the main bronchi and trachea) or group B (all other tumors). Risk factors for treatment-related death were tested in univariate analysis, and a logistic regression model was developed for fatal bronchopulmonary bleeding versus dose to the main bronchi and trachea.
A total of 65 patients (group A/group B, n = 39/26) were evaluated. The median distance between the tumor and the proximal bronchial tree was 0 mm (0–10 mm). The 2-year local control was 83%. Grade 3 to 5 toxicity was noted in 22 patients, including 10 cases of treatment-related death (bronchopulmonary hemorrhage, n = 8; pneumonitis, n = 1; fistula, n = 1). Dose to the combined structure main bronchi and trachea and tumor distance to the main bronchi were important risk factors. Dose modeling revealed minimum dose to the “hottest” 0.2 cc to the structure main bronchi and trachea as the strongest predictor for lethal bronchopulmonary hemorrhage.
On the basis of the presented data, 7 Gy × 8, prescribed to the planning target volume-encompassing isodose, should not be used for tumors located within 1 cm from the main bronchi and trachea. Group B-type tumors may be considered for the treatment on the basis of an individual risk-benefit assessment and a maximum dose to the main bronchi and trachea in the order of 70 to 80 Gy (equivalent dose in 2 Gy fractions).
Context.
Since about half of all main-sequence stars reside in multiple star systems, it is important to consider the effect of binarity on the evolution of planetesimal belts in these complex ...systems.
Aims.
We aim to see whether debris belts evolving between two stars may be impacted by the presence of the companion and whether this leaves any detectable signature that could be observed with current or future instruments.
Methods.
We consider a circumprimary parent body (PB) planetesimal belt that is placed just inside the stability limit between the two stars and we use the state-of-the-art DyCoSS code to follow the coupled dynamical and collisional evolution of the dust produced by this PB belt. We explore several free parameters, such as the belt’s mass and the binary’s mass ratio as well as its orbital eccentricity. We use the GraTeR package to produce 2D luminosity maps and system-integrated spectral energy distributions (SEDs).
Results.
We confirm a preliminary result obtained by previous DyCoSS studies, which is that the coupled effect of collisional activity, binary perturbations, and stellar radiation pressure is able to place and maintain a halo of small grains in the dynamically unstable region between the two stars. In addition, we identify several prominent spatial structures, notably, a single spiral arm stretching all the way from the PB belt to the companion star. We also identify a fainter and more compact disc around the secondary star, which is non-native and feeds off small grains from the unstable halo. The halo, spiral arm, and secondary disc should all be detectable on resolved images by instruments with capacities on the level of SPHERE. The system as a whole is depleted of small grains when compared to a companion-free case. This depletion leaves an imprint on the system’s integrated SED, which appears colder than for the same parent body belt around a single star. This new finding could explain why the SED-derived location,
r
disc
, of some unresolved discs-in-binaries places their primary belt in the dynamically ’forbidden’ region between the two stars: indeed, this apparent paradox could be due to an overestimation of
r
disc
when using empirical prescriptions that are valid for the case of a single star.
Context. The study of dynamical processes in protoplanetary disks is essential to understand planet formation. In this context, transition disks are prime targets because they are at an advanced ...stage of disk clearing and may harbor direct signatures of disk evolution. Aims. We aim to derive new constraints on the structure of the transition disk MWC 758, to detect non-axisymmetric features and understand their origin. Methods. We obtained infrared polarized intensity observations of the protoplanetary disk MWC 758 with VLT/SPHERE at 1.04 μm to resolve scattered light at a smaller inner working angle (0.093′′) and a higher angular resolution (0.027′′) than previously achieved. Results. We observe polarized scattered light within 0.53′′ (148 au) down to the inner working angle (26 au) and detect distinct non-axisymmetric features but no fully depleted cavity. The two small-scale spiral features that were previously detected with HiCIAO are resolved more clearly, and new features are identified, including two that are located at previously inaccessible radii close to the star. We present a model based on the spiral density wave theory with two planetary companions in circular orbits. The best model requires a high disk aspect ratio (H/r ~ 0.20 at the planet locations) to account for the large pitch angles which implies a very warm disk. Conclusions. Our observations reveal the complex morphology of the disk MWC 758. To understand the origin of the detected features, the combination of high-resolution observations in the submillimeter with ALMA and detailed modeling is needed.
Exocomets: A spectroscopic survey Rebollido, I.; Eiroa, C.; Montesinos, B. ...
Astronomy & astrophysics,
07/2020, Letnik:
639
Journal Article, Web Resource
Recenzirano
Odprti dostop
Context.
While exoplanets are now routinely detected, the detection of small bodies in extrasolar systems remains challenging. Since the discovery of sporadic events, which are interpreted to be ...exocomets (falling evaporating bodies) around
β
Pic in the early 1980s, only ∼20 stars have been reported to host exocomet-like events.
Aims.
We aim to expand the sample of known exocomet-host stars, as well as to monitor the hot-gas environment around stars with previously known exocometary activity.
Methods.
We have obtained high-resolution optical spectra of a heterogeneous sample of 117 main-sequence stars in the spectral type range from B8 to G8. The data were collected in 14 observing campaigns over the course of two years from both hemispheres. We analysed the Ca
II
K&H and Na
I
D lines in order to search for non-photospheric absorptions that originated in the circumstellar environment and for variable events that could be caused by the outgassing of exocomet-like bodies.
Results.
We detected non-photospheric absorptions towards 50% of the sample, thus attributing a circumstellar origin to half of the detections (i.e. 26% of the sample). Hot circumstellar gas was detected in the metallic lines inspected via narrow stable absorptions and/or variable blue- and red-shifted absorption events. Such variable events were found in 18 stars in the Ca
II
and/or Na
I
lines; six of them are reported in the context of this work for the first time. In some cases, the variations we report in the Ca
II
K line are similar to those observed in
β
Pic. While we do not find a significant trend in the age or location of the stars, we do find that the probability of finding CS gas in stars with larger
v
sin
i
is higher. We also find a weak trend with the presence of near-infrared excess and with anomalous (
λ
Boo-like) abundances, but this would require confirmation by expanding the sample.
Context. High-contrast instruments like SPHERE (Spectro- Polarimetric High-contrast Exoplanet REsearch) enable spatial resolution of young planetary systems and allow us to study the connection ...between planets and the dust contained in debris discs by the gravitational influence a planet can have on its environment. Aims. We present new observations of the edge-on debris disc around HD 15115 (F star at 48.2 pc) obtained in the near-IR. We search for observational evidence for a second inner planetesimal ring in the system. Methods. We obtained total intensity and polarimetric data in the broad bands J and H and processed the data with differential imaging techniques achieving an angular resolution of about 40 mas. A grid of models describing the spatial distribution of the grains in the disc is generated to constrain the geometric parameters of the disc and to explore the presence of a second belt. We perform a photometric analysis of the data and compare disc brightness in two bands in scattered and in polarized light. Results. We observe an axisymmetric planetesimal belt with a radius of ~2′′, an inclination of 85.8° ± 0.7° and position angle of 278.9° ± 0.1°. The photometric analysis shows that the west side is ~2.5 times brighter in total intensity than the east side in both bands, while for polarized light in the J band this ratio is only 1.25. We also find that the J–H colour of the disc appears to be red for the radial separations r ≲ 2′′ and is getting bluer for the larger separations. The maximum polarization fraction is 15–20% at r ~ 2.5′′. The polarized intensity image shows some structural features inside the belt which can be interpreted as an additional inner belt. Conclusions. The apparent change of disc colour from red to blue with an increasing radial separation from the star could be explained by the decreasing average grain size with distance. The presence of an inner belt slightly inclined with respect to the main planetesimal belt is suspected from the data but the analysis and modelling presented here cannot establish a firm conclusion due to the faintness of the disc and its high inclination.
Aims. To understand planet formation it is necessary to study the birth environment of planetary systems. Resolved imaging of young planet forming disks allows us to study this environment in great ...detail and find signs of planet-disk interaction and disk evolution. In the present study we aim to investigate the circumstellar environment of the spectroscopic binary T Tauri star CS Cha. From unresolved mid-to far-infrared photometry it is predicted that CS Cha hosts a disk with a large cavity. In addition, spectral energy distribution modeling suggests significant dust settling, pointing toward an evolved disk that may show signs of ongoing or completed planet formation. Methods. We observed CS Cha with the high contrast imager SPHERE at the ESO Very Large Telescope (VLT) in polarimetric differential imaging mode to resolve the circumbinary disk in near-infrared scattered light. These observations were followed up by VLT/NACO L-band observations and complemented by archival VLT/NACO K-band and Hubble Space Telescope WFPC2 I-band data. Results. We resolve the compact circumbinary disk around CS Cha for the first time in scattered light. We find a smooth, low inclination disk with an outer radius of ~55 au (at 165 pc). We do not detect the inner cavity but find an upper limit for the cavity size of ~15 au. Furthermore, we find a faint comoving companion with a projected separation of 210 au from the central binary outside of the circumbinary disk. The companion is detected in polarized light and shows an extreme degree of polarization (13.7 ± 0.4% in the J band). The J- and H-band magnitudes of the companion are compatible with masses of a few MJup. However, K-, L-, and I-band data draw this conclusion into question. We explore with radiative transfer modeling whether an unresolved circum-companion disk can be responsible for the high polarization and complex photometry. We find that the set of observations is best explained by a heavily extincted low-mass (~20 MJup) brown dwarf or high-mass planet with an unresolved disk and dust envelope.
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