186 research outputs found
An ultra-deep multi-band VLA survey of the faint radio sky (COSMOS-XS): New constraints on the cosmic star formation history
We make use of ultra-deep 3 GHz Karl G. Jansky Very Large Array observations
of the COSMOS field from the multi-band COSMOS-XS survey to infer radio
luminosity functions (LFs) of star-forming galaxies (SFGs). Using 1300
SFGs with redshifts out to , and fixing the faint and bright end
shape of the radio LF to the local values, we find a strong redshift trend that
can be fitted by pure luminosity evolution with the luminosity parameter given
by . We then combine the
ultra-deep COSMOS-XS data-set with the shallower VLA-COSMOS
large project data-set over the wider COSMOS field in order to fit for joint
density+luminosity evolution, finding evidence for significant density
evolution. By comparing the radio LFs to the observed far-infrared (FIR) and
ultraviolet (UV) LFs, we find evidence of a significant underestimation of the
UV LF by at high redshift (,
integrated down to ). We derive the cosmic star
formation rate density (SFRD) by integrating the fitted radio LFs and find that
the SFRD rises up to and then declines more rapidly than
previous radio-based estimates. A direct comparison between the radio SFRD and
a recent UV-based SFRD, where we integrate both LFs down to a consistent limit
(), reveals that the discrepancy between the radio and
UV LFs translates to a significant (1 dex) discrepancy in the derived
SFRD at , even assuming the latest dust corrections and without accounting
for optically dark sources.Comment: Submitted to ApJ; 27 pages, 13 figures, 4 table
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
Understanding the individual to implement the ecosystem approach to fisheries management
Ecosystem-based approaches to fisheries management (EAFMs) have emerged as requisite for sustainable use of fisheries resources. At the same time, however, there is a growing recognition of the degree of variation among individuals within a population, as well as the ecological consequences of this variation. Managing resources at an ecosystem level calls on practitioners to consider evolutionary processes, and ample evidence from the realm of fisheries science indicates that anthropogenic disturbance can drive changes in predominant character traits (e.g. size at maturity). Eco-evolutionary theory suggests that human-induced trait change and the modification of selective regimens might contribute to ecosystem dynamics at a similar magnitude to species extirpation, extinction and ecological dysfunction. Given the dynamic interaction between fisheries and target species via harvest and subsequent ecosystem consequences, we argue that individual diversity in genetic, physiological and behavioural traits are important considerations under EAFMs. Here, we examine the role of individual variation in a number of contexts relevant to fisheries management, including the potential ecological effects of rapid trait change. Using select examples, we highlight the extent of phenotypic diversity of individuals, as well as the ecological constraints on such diversity. We conclude that individual phenotypic diversity is a complex phenomenon that needs to be considered in EAFMs, with the ultimate realization that maintaining or increasing individual trait diversity may afford not only species, but also entire ecosystems, with enhanced resilience to environmental perturbations. Put simply, individuals are the foundation from which population- and ecosystem-level traits emerge and are therefore of central importance for the ecosystem-based approaches to fisheries management
Extremely deep 150 MHz source counts from the LoTSS Deep Fields
International audienceWith the advent of new generation low-frequency telescopes, such as the LOw Frequency ARray (LOFAR), and improved calibration techniques, we have now started to unveil the subgigahertz radio sky with unprecedented depth and sensitivity. The LOFAR Two Meter Sky Survey (LoTSS) is an ongoing project in which the whole northern radio sky will be observed at 150 MHz with a sensitivity better than 100 μJy beam−1 at a resolution of 6′′. Additionally, deeper observations are planned to cover smaller areas with higher sensitivity. The Lockman Hole, the Boötes, and the Elais-N1 regions are among the most well known northern extra-galactic fields and the deepest of the LoTSS Deep Fields so far. We exploited these deep observations to derive the deepest radio source counts at 150 MHz to date. Our counts are in broad agreement with those from the literature and show the well known upturn at ≤1 mJy, mainly associated with the emergence of the star-forming galaxy population. More interestingly, our counts show, for the first time a very pronounced drop around S ~ 2 mJy, which results in a prominent “bump” at sub-mJy flux densities. Such a feature was not observed in previous counts’ determinations (neither at 150 MHz nor at a higher frequency). While sample variance can play a role in explaining the observed discrepancies, we believe this is mostly the result of a careful analysis aimed at deblending confused sources and removing spurious sources and artifacts from the radio catalogs. This “drop and bump” feature cannot be reproduced by any of the existing state-of-the-art evolutionary models, and it appears to be associated with a deficiency of active galactic nuclei (AGN) at an intermediate redshift (1 < z < 2) and an excess of low-redshift (z < 1) galaxies and/or AGN.Key words: galaxies: evolution / surveys / radio continuum: genera
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 > 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 > 6.5 by ∼4-5× to >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 > 6.5 universe, such that the number of ALMA-derived redshifts at z > 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 >28 M yr-1. These new LP results further demonstrate ALMA's efficiency as a "redshift machine,"particularly in the Epoch of Reionization
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