109 research outputs found

    Being relevant: Practical guidance for early career researchers interested in solving conservation problems

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    AbstractIn a human-altered world where biodiversity is in decline and conservation problems abound, there is a dire need to ensure that the next generation of conservation scientists have the knowledge, skills, and training to address these problems. So called ā€œearly career researchersā€ (ECRs) in conservation science have many challenges before them and it is clear that the status quo must change to bridge the knowledgeā€“action divide. Here we identify thirteen practical strategies that ECRs can employ to become more relevant. In this context, ā€œrelevanceā€ refers to the ability to contribute to solving conservation problems through engagement with practitioners, policy makers, and stakeholders. Conservation and career strategies outlined in this article include the following: thinking ā€˜big pictureā€™ during conservation projects; embracing various forms of knowledge; maintaining positive relationships with locals familiar with the conservation issue; accepting failure as a viable (and potentially valuable) outcome; daring to be creative; embracing citizen science; incorporating interdisciplinarity; promoting and practicing pro-environmental behaviours; understanding financial aspects of conservation; forming collaboration from the onset of a project; accepting the limits of technology; ongoing and effective networking; and finally, maintaining a positive outlook by focusing on and sharing conservation success stories. These strategies move beyond the generic and highlight the importance of continuing to have an open mind throughout the entire conservation process, from establishing oneā€™s self as an asset to embracing collaboration and interdisciplinary work, and striving to push for professional and personal connections that strengthen personal career objectives

    The Importance of Time Congruity in the Organisation.

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    In 1991 Kaufman, Lane, and Lindquist proposed that time congruity in terms of an individual's time preferences and the time use methods of an organisation would lead to satisfactory performance and enhancement of quality of work and general life. The research reported here presents a study which uses commensurate person and job measures of time personality in an organisational setting to assess the effects of time congruity on one aspect of work life, job-related affective well-being. Results show that time personality and time congruity were found to have direct effects on well-being and the influence of time congruity was found to be mediated through time personality, thus contributing to the personā€“job (Pā€“J) fit literature which suggests that direct effects are often more important than indirect effects. The study also provides some practical examples of ways to address some of the previously cited methodological issues in Pā€“J fit research

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

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    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 Ī¼m and [O iii]88 Ī¼m 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 āˆ¼4-5Ɨ 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 ā‰„ 7Ļƒ [C ii]158 Ī¼m lines have already been discovered, the bulk of which (13/18) also show ā‰„3.3Ļƒ 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 LyĪ± discoveries. An analysis of the completeness of our search results versus star formation rate (SFR) suggests an āˆ¼79% efficiency in scanning for [C ii]158 Ī¼m 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

    The ALMA REBELS survey: the dust content of z āˆ¼7 Lyman break galaxies

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    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 ā‰ƒ 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 Ļ„0 = 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(ĻˆUV) = -0.05 [log(Ļˆ)]2 + 0.86 log(Ļˆ) - 0.05 (implying that 55-80 per cent of the star formation is obscured) for REBELS galaxies with stellar mass Māˆ— = 109-1010 MāŠ™. 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 Ļ„0 to very low values (0.3 Myr) only increases the dust-to-stellar mass ratio by a factor of āˆ¼2. Given that grain growth is not a viable explanation for such high observed ratios of the dust-to-stellar mass, we propose alternative solutions

    Extremely deep 150 MHz source counts from the LoTSS Deep Fields

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    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 Ī¼Jy beamāˆ’1 at a resolution of 6ā€²ā€². Additionally, deeper observations are planned to cover smaller areas with higher sensitivity. The Lockman Hole, the Boƶtes, 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 ā‰¤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 ā€œbumpā€ at sub-mJy flux densities. Such a feature was not observed in previous countsā€™ 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 ā€œdrop and bumpā€ 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

    Effect of surgical volume on short-term outcomes of cytoreductive surgery for advanced-stage ovarian cancer:A population-based study from the Dutch Gynecological Oncology Audit

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    Objective:Ā Despite lacking clinical data, the Dutch government is considering increasing the minimum annual surgical volume per center from twenty to fifty cytoreductive surgeries (CRS) for advanced-stage ovarian cancer (OC). This study aims to evaluate whether this increase is warranted.Ā Methods:Ā This population-based study included all CRS for FIGO-stage IIB-IVB OC registered in eighteen Dutch hospitals between 2019 and 2022. Short-term outcomes included result of CRS, length of stay, severe complications, 30-day mortality, time to adjuvant chemotherapy, and textbook outcome. Patients were stratified by annual volume: low-volume (nine hospitals, &lt;25), medium-volume (four hospitals, 29ā€“37), and high-volume (five hospitals, 54ā€“84). Descriptive statistics and multilevel logistic regressions were used to assess the (case-mix adjusted) associations of surgical volume and outcomes.Ā Results:Ā A total of 1646 interval CRS (iCRS) and 789 primary CRS (pCRS) were included. No associations were found between surgical volume and different outcomes in the iCRS cohort. In the pCRS cohort, high-volume was associated with increased complete CRS rates (aOR 1.9, 95%-CI 1.2ā€“3.1, p = 0.010). Furthermore, high-volume was associated with increased severe complication rates (aOR 2.3, 1.1ā€“4.6, 95%-CI 1.3ā€“4.2, p = 0.022) and prolonged length of stay (aOR 2.3, 95%-CI 1.3ā€“4.2, p = 0.005). 30-day mortality, time to adjuvant chemotherapy, and textbook outcome were not associated with surgical volume in the pCRS cohort. Subgroup analyses (FIGO-stage IIIC-IVB) showed similar results. Various case-mix factors significantly impacted outcomes, warranting case-mix adjustment.Ā Conclusions:Ā Our analyses do not support further centralization of iCRS for advanced-stage OC. High-volume was associated with higher complete pCRS, suggesting either a more accurate selection in these hospitals or a more aggressive approach. The higher completeness rates were at the expense of higher severe complications and prolonged admissions.</p

    The ALMA REBELS survey: obscured star formation in massive Lyman-break galaxies at z = 4-8 revealed by the IRX-Ī²\beta and Mā‹†M_{\star} relations

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    We investigate the degree of dust obscured star formation in 49 massive (log10(Mā‹†/MāŠ™)>9{\rm log}_{10}(M_{\star}/{\rm M}_{\odot})>9) Lyman-break galaxies (LBGs) at z=6.5z = 6.5-88 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 (fobs=0.4f_{\rm obs} = 0.4-0.70.7) 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 (Ī²ā‰ƒāˆ’2.2\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 Td=46ā€‰KT_{\rm d} = 46\,{\rm K} and Ī²d=2.0\beta_{\rm d} = 2.0), we find that the REBELS sources are in agreement with the local ''Calzetti-like'' starburst Infrared-excess (IRX)-Ī²\beta relation. By reanalysing the data available for 108 galaxies at zā‰ƒ4z \simeq 4-66 from the ALPINE ALMA large program using a consistent methodology and assumed FIR SED, we show that from zā‰ƒ4z \simeq 4-88, massive galaxies selected in the rest-frame UV have no appreciable evolution in their derived IRX-Ī²\beta relation. When comparing the IRX-Mā‹†M_{\star} relation derived from the combined ALPINE and REBELS sample to relations established at z<4z < 4, we find a deficit in the IRX, indicating that at z>4z > 4 the proportion of obscured star formation is lower by a factor of ā‰³3\gtrsim 3 at a given a Mā‹†M_{\star}. Our IRX-Ī²\beta results are in good agreement with the high-redshift predictions of simulations and semi-analytic models for zā‰ƒ7z \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-ALPINE [CII] survey: Kennicutt-Schmidt relation in four massive main-sequence galaxies at z~4.5

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    The Kennicutt-Schmidt (KS) relation between the gas and the star formation rate (SFR) surface density (Ī£gas\Sigma_{\rm gas}-Ī£SFR\Sigma_{\rm SFR}) is essential to understand star formation processes in galaxies. So far, it has been measured up to z~2.5 in main-sequence galaxies. In this letter, we aim to put constraints at z~4.5 using a sample of four massive main-sequence galaxies observed by ALMA at high resolution. We obtained ~0.3"-resolution [CII] and continuum maps of our objects, which we then converted into gas and obscured SFR surface density maps. In addition, we produced unobscured SFR surface density maps by convolving Hubble ancillary data in the rest-frame UV. We then derived the average Ī£SFR\Sigma_{\rm SFR} in various Ī£gas\Sigma_{\rm gas} bins, and estimated the uncertainties using a Monte Carlo sampling. Our galaxy sample follows the KS relation measured in main-sequence galaxies at lower redshift and is slightly lower than predictions from simulations. Our data points probe the high end both in terms of Ī£gas\Sigma_{\rm gas} and Ī£gas\Sigma_{\rm gas}, and gas depletion timescales (285-843 Myr) remain similar to z~2 objects. However, three of our objects are clearly morphologically disturbed, and we could have expected shorter gas depletion timescales (~100 Myr) similar to merger-driven starbursts at lower redshifts. This suggests that the mechanisms triggering starbursts at high redshift may be different than in the low- and intermediate-z Universe.Comment: 9 pages, 7 figures, 2 tables, accepted by A&A (letter
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