De plant in rust

Rectorale oratie Vrije Universiteit 196

Exploring global barriers to optimal ovarian cancer care:thematic analysis

Objective: To explore the barriers to ovarian cancer care, as reported in the open ended responses of a global expert opinion survey, highlighting areas for improvement in global ovarian cancer care. Potential solutions to overcome these barriers are proposed. Methods: Data from the expert opinion survey, designed to assess the organization of ovarian cancer care worldwide, were analyzed. The survey was distributed across a global network of physicians. We examined free text, open ended responses concerning the barriers to ovarian cancer care. A qualitative thematic analysis was conducted to identify, analyze, and report meaningful patterns within the data. Results: A total of 1059 physicians from 115 countries completed the survey, with 438 physicians from 93 countries commenting on the barriers to ovarian cancer care. Thematic analysis gave five major themes, regardless of income category or location: societal factors, inadequate resources in hospital, economic barriers, organization of the specialty, and need for early detection. Suggested solutions include accessible resource stratified guidelines, multidisciplinary teamwork, public education, and development of gynecological oncology training pathways internationally. Conclusions: This analysis provides an international perspective on the main barriers to optimal ovarian cancer care. The themes derived from our analysis highlight key target areas to focus efforts to reduce inequalities in global care. Future regional analysis involving local representatives will enable country specific recommendations to improve the quality of care and ultimately to work towards closing the care gap

Exploring global barriers to optimal ovarian cancer care:thematic analysis

Objective: To explore the barriers to ovarian cancer care, as reported in the open ended responses of a global expert opinion survey, highlighting areas for improvement in global ovarian cancer care. Potential solutions to overcome these barriers are proposed. Methods: Data from the expert opinion survey, designed to assess the organization of ovarian cancer care worldwide, were analyzed. The survey was distributed across a global network of physicians. We examined free text, open ended responses concerning the barriers to ovarian cancer care. A qualitative thematic analysis was conducted to identify, analyze, and report meaningful patterns within the data. Results: A total of 1059 physicians from 115 countries completed the survey, with 438 physicians from 93 countries commenting on the barriers to ovarian cancer care. Thematic analysis gave five major themes, regardless of income category or location: societal factors, inadequate resources in hospital, economic barriers, organization of the specialty, and need for early detection. Suggested solutions include accessible resource stratified guidelines, multidisciplinary teamwork, public education, and development of gynecological oncology training pathways internationally. Conclusions: This analysis provides an international perspective on the main barriers to optimal ovarian cancer care. The themes derived from our analysis highlight key target areas to focus efforts to reduce inequalities in global care. Future regional analysis involving local representatives will enable country specific recommendations to improve the quality of care and ultimately to work towards closing the care gap

Exploring international differences in ovarian cancer care: a survey report on global patterns of care, current practices, and barriers

OBJECTIVE: Although global disparities in survival rates for patients with ovarian cancer have been described, variation in care has not been assessed globally. This study aimed to evaluate global ovarian cancer care and barriers to care. METHODS: A survey was developed by international ovarian cancer specialists and was distributed through networks and organizational partners of the International Gynecologic Cancer Society, the Society of Gynecologic Oncology, and the European Society of Gynecological Oncology. Respondents received questions about care organization. Outcomes were stratified by World Bank Income category and analyzed using descriptive statistics and logistic regressions. RESULTS: A total of 1059 responses were received from 115 countries. Respondents were gynecological cancer surgeons (83%, n=887), obstetricians/gynecologists (8%, n=80), and other specialists (9%, n=92). Income category breakdown was as follows: high-income countries (46%), upper-middle-income countries (29%), and lower-middle/low-income countries (25%). Variation in care organization was observed across income categories. Respondents from lower-middle/low-income countries reported significantly less frequently that extensive resections were routinely performed during cytoreductive surgery. Furthermore, these countries had significantly fewer regional networks, cancer registries, quality registries, and patient advocacy groups. However, there is also scope for improvement in these components in upper-middle/high-income countries. The main barriers to optimal care for the entire group were patient co-morbidities, advanced presentation, and social factors (travel distance, support systems). High-income respondents stated that the main barriers were lack of surgical time/staff and patient preferences. Middle/low-income respondents additionally experienced treatment costs and lack of access to radiology/pathology/genetic services as main barriers. Lack of access to systemic agents was reported by one-third of lower-middle/low-income respondents. CONCLUSIONS: The current survey report highlights global disparities in the organization of ovarian cancer care. The main barriers to optimal care are experienced across all income categories, while additional barriers are specific to income levels. Taking action is crucial to improve global care and strive towards diminishing survival disparities and closing the care gap

The ALMA REBELS Survey: The First Infrared Luminosity Function Measurement at $\mathbf{z \sim 7}

We present the first observational infrared luminosity function (IRLF) measurement in the Epoch of Reionization (EoR) based on a UV-selected galaxy sample with ALMA spectroscopic observations. Our analysis is based on the ALMA large program Reionization Era Bright Emission Line Survey (REBELS), which targets 42 galaxies at $\mathrm{z=6.4-7.7}$ with [CII] 158\micron line scans. 16 sources exhibit a dust detection, 15 of which are also spectroscopically confirmed through the [CII] line. The IR luminosities of the sample range from $\log L_{IR}/L_\odot=11.4$ to 12.2. Using the UVLF as a proxy to derive the effective volume for each of our target sources, we derive IRLF estimates, both for detections and for the full sample including IR luminosity upper limits. The resulting IRLFs are well reproduced by a Schechter function with the characteristic luminosity of $\log L_{*}/L_\odot=11.6^{+0.2}_{-0.1}$. Our observational results are in broad agreement with the average of predicted IRLFs from simulations at $z\sim7$. Conversely, our IRLFs lie significantly below lower redshift estimates, suggesting a rapid evolution from $z\sim4$ to $z\sim7$, into the reionization epoch. The inferred obscured contribution to the cosmic star-formation rate density at $z\sim7$ amounts to $\mathrm{log(SFRD/M_{\odot}/yr/Mpc^{3}) = -2.66^{+0.17}_{-0.14} }$ which is at least $\sim$10\% of UV-based estimates. We conclude that the presence of dust is already abundant in the EoR and discuss the possibility of unveiling larger samples of dusty galaxies with future ALMA and JWST observations.Comment: 9 pages, 5 figure

The ALMA REBELS Survey : specific star formation rates in the reionization era

We present specific star formation rates (sSFRs) for 40 ultraviolet (UV)-bright galaxies at z ∼ 7–8 observed as part of the Reionization Era Bright Emission Line Survey (REBELS) Atacama Large Millimeter/submillimeter Array (ALMA) large programme. The sSFRs are derived using improved star formation rate (SFR) calibrations and spectral energy distribution (SED)based stellar masses, made possible by measurements of far-infrared (FIR) continuum emission and [C II]-based spectroscopic redshifts. The median sSFR of the sample is 18+−57 Gyr−1, significantly larger than literature measurements lacking constraints in the FIR, reflecting the larger obscured SFRs derived from the dust continuum relative to that implied by the UV+optical SED. We suggest that such differences may reflect spatial variations in dust across these luminous galaxies, with the component dominating the FIR distinct from that dominating the UV. We demonstrate that the inferred stellar masses (and hence sSFRs) are strongly dependent on the assumed star formation history in reionization-era galaxies. When large sSFR galaxies (a population that is common at z > 6) are modelled with non-parametric star formation histories, the derived stellar masses can increase by an order of magnitude relative to constant star formation models, owing to the presence of a significant old stellar population that is outshined by the recent burst. The [C II] line widths in the largest sSFR systems are often very broad, suggesting dynamical masses capable of accommodating an old stellar population suggested by non-parametric models. Regardless of these systematic uncertainties among derived parameters, we find that sSFRs increase rapidly toward higher redshifts for massive galaxies (9.6 < log (M∗/M☉) < 9.8), evolving as (1 + z)1.7±0.3, broadly consistent with expectations from the evolving baryon accretion rates

The ALMA REBELS Survey: the first infrared luminosity function measurement at z ∼ 7

We present the first observational infrared luminosity function (IRLF) measurement in the Epoch of Reionization (EoR) based on a ultraviolet (UV)-selected galaxy sample with the Atacama Large Millimeter Array (ALMA) spectroscopic observations. Our analysis is based on the ALMA large program Reionization Era Bright Emission Line Survey (REBELS), which targets 42 galaxies at z = 6.4–7.7 with [C II] 158 μm line scans. 16 sources exhibit dust detection, 15 of which are also spectroscopically confirmed through the [C II] line. The infrared (IR) luminosities of the sample range from log LIR/L⊙ = 11.4 to 12.2. Using the UV luminosity function as a proxy to derive the effective volume for each of our target sources, we derive IRLF estimates, both for detections and for the full sample including IR luminosity upper limits. The resulting IRLFs are well reproduced by a Schechter function with the characteristic luminosity of logL∗/L⊙=11.6+0.2−0.1 . Our observational results are in broad agreement with the average of predicted IRLFs from simulations at z ∼ 7. Conversely, our IRLFs lie significantly below lower redshift estimates, suggesting a rapid evolution from z ∼ 4 to z ∼ 7, into the reionization epoch. The IR obscured contribution to the cosmic star formation rate density at z ∼ 7 amounts to log(SFRD/M⊙yr−1Mpc−3)=−2.66+0.17−0.14 that is at least ∼10 per cent of UV-based estimates. We conclude that the presence of dust is already abundant in the EoR and discuss the possibility of unveiling larger samples of dusty galaxies with future ALMA and JWST observations

The ALMA REBELS survey: obscured star formation in massive Lyman-break galaxies at z = 4-8 revealed by the IRX-β\beta and M⋆M_{\star} relations

We investigate the degree of dust obscured star formation in 49 massive (${\rm log}_{10}(M_{\star}/{\rm M}_{\odot})>9$) Lyman-break galaxies (LBGs) at $z = 6.5$-$8$ observed as part of the ALMA Reionization Era Bright Emission Line Survey (REBELS) large program. By creating deep stacks of the photometric data and the REBELS ALMA measurements we determine the average rest-frame UV, optical and far-infrared (FIR) properties which reveal a significant fraction ($f_{\rm obs} = 0.4$-$0.7$) of obscured star formation, consistent with previous studies. From measurements of the rest-frame UV slope, we find that the brightest LBGs at these redshifts show bluer ($\beta \simeq -2.2$) colours than expected from an extrapolation of the colour-magnitude relation found at fainter magnitudes. Assuming a modified blackbody spectral-energy distribution (SED) in the FIR (with dust temperature of $T_{\rm d} = 46\,{\rm K}$ and $\beta_{\rm d} = 2.0$), we find that the REBELS sources are in agreement with the local ''Calzetti-like'' starburst Infrared-excess (IRX)-$\beta$ relation. By reanalysing the data available for 108 galaxies at $z \simeq 4$-$6$ from the ALPINE ALMA large program using a consistent methodology and assumed FIR SED, we show that from $z \simeq 4$-$8$, massive galaxies selected in the rest-frame UV have no appreciable evolution in their derived IRX-$\beta$ relation. When comparing the IRX-$M_{\star}$ relation derived from the combined ALPINE and REBELS sample to relations established at $z < 4$, we find a deficit in the IRX, indicating that at $z > 4$ the proportion of obscured star formation is lower by a factor of $\gtrsim 3$ at a given a $M_{\star}$. Our IRX-$\beta$ results are in good agreement with the high-redshift predictions of simulations and semi-analytic models for $z \simeq 7$ galaxies with similar stellar masses and SFRs.Comment: 18 pages, 10 figures, 2 tables (plus 1 figure and 2 tables in the appendix). Updated to match MNRAS accepted version after minor correction

The ALMA REBELS survey: the dust content of z ∼7 Lyman break galaxies

We include a fully coupled treatment of metal and dust enrichment into the Delphi semi-analytic model of galaxy formation to explain the dust content of 13 Lyman break galaxies (LBGs) detected by the Atacama Large millimetre Array (ALMA) REBELS Large Program at z ≃ 7. We find that the galaxy dust mass, Md, is regulated by the combination of Type II supernova dust production, astration, shock destruction, and ejection in outflows; grain growth (with a standard time-scale τ0 = 30 Myr) plays a negligible role. The model predicts a dust-to-stellar mass ratio of ~ 0.07-0.1per cent and a UV-to-total star formation rate relation such that log(ψUV) = -0.05 [log(ψ)]2 + 0.86 log(ψ) - 0.05 (implying that 55-80 per cent of the star formation is obscured) for REBELS galaxies with stellar mass M∗ = 109-1010 M⊙. This relation reconciles the intrinsic UV luminosity of LBGs with their observed luminosity function at z = 7. However, 2 out of the 13 systems show dust-to-stellar mass ratios (~0.94-1.1per cent) that are up to 18 times larger than expected from the fiducial relation. Due to the physical coupling between dust and metal enrichment, even decreasing τ0 to very low values (0.3 Myr) only increases the dust-to-stellar mass ratio by a factor of ∼2. Given that grain growth is not a viable explanation for such high observed ratios of the dust-to-stellar mass, we propose alternative solutions

Reionization Era Bright Emission Line Survey: selection and characterization of luminous interstellar medium reservoirs in the z > 6.5 universe

The Reionization Era Bright Emission Line Survey (REBELS) is a cycle-7 ALMA Large Program (LP) that is identifying and performing a first characterization of many of the most luminous star-forming galaxies known in the z &gt; 6.5 universe. REBELS is providing this probe by systematically scanning 40 of the brightest UV-selected galaxies identified over a 7 deg2 area for bright [C ii]158 μm and [O iii]88 μm lines and dust-continuum emission. Selection of the 40 REBELS targets was done by combining our own and other photometric selections, each of which is subject to extensive vetting using three completely independent sets of photometry and template-fitting codes. Building on the observational strategy deployed in two pilot programs, we are increasing the number of massive interstellar medium (ISM) reservoirs known at z &gt; 6.5 by ∼4-5× to &gt;30. In this manuscript, we motivate the observational strategy deployed in the REBELS program and present initial results. Based on the first-year observations, 18 highly significant ≥ 7σ [C ii]158 μm lines have already been discovered, the bulk of which (13/18) also show ≥3.3σ dust-continuum emission. These newly discovered lines more than triple the number of bright ISM-cooling lines known in the z &gt; 6.5 universe, such that the number of ALMA-derived redshifts at z &gt; 6.5 rival Lyα discoveries. An analysis of the completeness of our search results versus star formation rate (SFR) suggests an ∼79% efficiency in scanning for [C ii]158 μm when the SFRUV+IR is &gt;28 M yr-1. These new LP results further demonstrate ALMA's efficiency as a "redshift machine,"particularly in the Epoch of Reionization