43 research outputs found

    The relative effects of pace of life-history and habitat characteristics on the evolution of sexual ornaments: A comparative assessment

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    Selection may favor greater investment into sexual ornaments when opportunities for future reproduction are limited, for example, under high adult mortality. However, predation, a key driver of mortality, typically selects against elaborate sexual ornaments. Here, we examine the evolution of sexual ornaments in killifishes, which have marked contrasts in life-history strategy among species and inhabit environments that differ in accessibility to aquatic predators. We first assessed if the size of sexual ornaments (unpaired fins) influenced swimming performance. Second, we investigated whether the evolution of larger ornamental fins is driven primarily by the pace of life-history (investment into current vs. future reproduction) or habitat type (a proxy for predation risk). We found that larger fins negatively affected swimming performance. Further, males from species inhabiting ephemeral habitats, with lower predation risk, had larger fins and greater sexual dimorphism in fin size, compared to males from more accessible permanent habitats. We show that enlarged ornamental fins, which impair locomotion, evolve more frequently in environments that are less accessible to predators, without clear associations to life-history strategy. Our results provide a rare link between the evolution of sexual ornaments, effects on locomotion performance, and natural selection on ornament size potentially through habitat differences in predation risk

    Universality for bounded degree spanning trees in randomly perturbed graphs

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    We solve a problem of Krivelevich, Kwan and Sudakov concerning the threshold for the containment of all bounded degree spanning trees in the model of randomly perturbed dense graphs. More precisely, we show that, if we start with a dense graph G α on n vertices with ÎŽ(G α ) ≄ αn for α > 0 and we add to it the binomial random graph G(n,C/n), then with high probability the graph G α âˆȘG(n,C/n) contains copies of all spanning trees with maximum degree at most Δ simultaneously, where C depends only on α and Δ

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    1. Demski, DagnosƂaw – Baraniecka-Olszewska, Kamila (eds.): Images of the Other in Ethnic Caricatures of Central and Eastern Europe. 2010, Warsaw: Institute of Archaeology and Ethnology, Polish Academy of Sciences. 400. ISBN 978-83-89499-76-9; Demski, DagnosƂaw – KristĂłf, IldikĂł Sz. – Baraniecka-Olszewska, Kamila (eds.): Competing Eyes: Visual Encounters with Alterity in Central and Eastern Europe. 2013, Budapest: L’Harmattan. 546. ISBN: 978-963-236-706-4; Demski, DagnosƂaw - Laineste, Liisi – Baraniecka-Olszewska, Kamila (eds.): War Matters. Constructing Images of the Other (1930s to 1950s). 2015, Budapest: L’Harmattan. 463. ISBN: 978-2-343-07233-3; Demski, DagnosƂaw – Kassabova, Anelia – KristĂłf, IldikĂł Sz. – Laineste, Liisi – Baraniecka-Olszewska, Kamila (eds.): The Multi-mediatized Other. The Construction of Reality in East-Central Europe, 1945–1980. 2017. Budapest: L’Harmattan. 630. ISBN: 978-2-343- 11863-5 2. Kondrasiuk, Grzegorz (ed.): Cyrk w ƛwiecie widowisk [Circus in the World of Spectacles]. 2017, Lublin: Warsztaty Kultury w Lublinie. 478. 117 color illustrations, abstracts in English. ISBN 978-83-64375-26-2 3. Ziolkowski, Jan M.: The Juggler of Notre Dame and Medivalizing of Modernity. Volume 1: The Middle Ages. 2018, Cambridge, UK: Open Book Publishers. 403, 152 illustrations: 67 black and white, 85 in color. ISBN 978-1-78374-506-7 4. RĂ©gi TamĂĄs: MinimĂĄlis AntropolĂłgia [Minimal Anthropology]. 2017, Budapest: Qadmon KiadĂł. 197. ISBN 978-615-810-440-1 5. Keszeg Vilmos: A beszĂ©lĂ©s antropolĂłgiĂĄja. [Anthropology of Speaking. Notes for Students.] (NĂ©prajzi Egyetemi Jegyzetek 9). 2018, KolozsvĂĄr: Kriza JĂĄnos NĂ©prajzi TĂĄrsasĂĄg – BBTE Magyar NĂ©prajz Ă©s KulturĂĄlis AntropolĂłgia IntĂ©zet. 498. ISBN 978-606-9015-05-6 6. Rozwadowski, Andrzej: Rocks, Cracks and Drums: In Search of Ancient Shamanism in Siberia and Central Asia (Translated from Polish by Anieszka Tokarczuk). 2017, Budapest: MolnĂĄr & Kelemen Oriental Publishers. 166. ISBN 978-9-6388-2386-

    Characterization of a genomic signature of pregnancy identified in the breast.

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    The objective of this study was to comprehensively compare the genomic profiles in the breast of parous and nulliparous postmenopausal women to identify genes that permanently change their expression following pregnancy. The study was designed as a two-phase approach. In the discovery phase, we compared breast genomic profiles of 37 parous with 18 nulliparous postmenopausal women. In the validation phase, confirmation of the genomic patterns observed in the discovery phase was sought in an independent set of 30 parous and 22 nulliparous postmenopausal women. RNA was hybridized to Affymetrix HG_U133 Plus 2.0 oligonucleotide arrays containing probes to 54,675 transcripts, scanned and the images analyzed using Affymetrix GCOS software. Surrogate variable analysis, logistic regression, and significance analysis of microarrays were used to identify statistically significant differences in expression of genes. The false discovery rate (FDR) approach was used to control for multiple comparisons. We found that 208 genes (305 probe sets) were differentially expressed between parous and nulliparous women in both discovery and validation phases of the study at an FDR of 10% and with at least a 1.25-fold change. These genes are involved in regulation of transcription, centrosome organization, RNA splicing, cell-cycle control, adhesion, and differentiation. The results provide initial evidence that full-term pregnancy induces long-term genomic changes in the breast. The genomic signature of pregnancy could be used as an intermediate marker to assess potential chemopreventive interventions with hormones mimicking the effects of pregnancy for prevention of breast cancer

    Characterization of a genomic signature of pregnancy identified in the breast.

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    The objective of this study was to comprehensively compare the genomic profiles in the breast of parous and nulliparous postmenopausal women to identify genes that permanently change their expression following pregnancy. The study was designed as a two-phase approach. In the discovery phase, we compared breast genomic profiles of 37 parous with 18 nulliparous postmenopausal women. In the validation phase, confirmation of the genomic patterns observed in the discovery phase was sought in an independent set of 30 parous and 22 nulliparous postmenopausal women. RNA was hybridized to Affymetrix HG_U133 Plus 2.0 oligonucleotide arrays containing probes to 54,675 transcripts, scanned and the images analyzed using Affymetrix GCOS software. Surrogate variable analysis, logistic regression, and significance analysis of microarrays were used to identify statistically significant differences in expression of genes. The false discovery rate (FDR) approach was used to control for multiple comparisons. We found that 208 genes (305 probe sets) were differentially expressed between parous and nulliparous women in both discovery and validation phases of the study at an FDR of 10% and with at least a 1.25-fold change. These genes are involved in regulation of transcription, centrosome organization, RNA splicing, cell-cycle control, adhesion, and differentiation. The results provide initial evidence that full-term pregnancy induces long-term genomic changes in the breast. The genomic signature of pregnancy could be used as an intermediate marker to assess potential chemopreventive interventions with hormones mimicking the effects of pregnancy for prevention of breast cancer

    A cross-sectional study of different patterns of oral contraceptive use among premenopausal women and circulating IGF-1: implications for disease risk

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    <p>Abstract</p> <p>Background</p> <p>Insulin-like growth factor-1 (IGF-1) is important in normal growth, development, and homeostasis. Current use of oral contraceptives (OC) decreases IGF-1 concentrations; however, the effect of past use, age/timing of use, and type of OC used on IGF-1 levels is unknown. OC are the most commonly used form of birth control worldwide. Both IGF-1 and OC use have been linked to premenopausal breast and colorectal cancers, osteoporosis and cardiovascular disease (CVD). Understanding the effects of different patterns of OC use on IGF-1 levels may offer insight into its influence on disease risk in young women.</p> <p>Methods</p> <p>In a cross-sectional study of 328 premenopausal women ages 18 to 21 and 31 to 40 we examined the relationship between different patterns of OC use and circulating IGF-1 using adjusted linear regression analysis. Information on OC use was obtained through an interviewer administered questionnaire. Plasma IGF-1 was assessed with enzyme linked immunosorbent assay (ELISA).</p> <p>Results</p> <p>Among women aged 18 to 21, ever OC use was significantly associated with decreased IGF-1 levels compared to never use (ÎČ = -57.2 ng/ml, 95% confidence interval (CI): -88.7, -25.8). Among women aged 31 to 40, past users who first used OC at 25 years of age or older (ÎČ = 43.8 ng/ml, 95% CI: 8.8, 78.8), in the last 15 years (ÎČ = 35.1 ng/ml, 95% CI: 9.3, 61.0) or after 1995 (ÎČ = 46.6 ng/ml, 95% CI: 13.4, 79.8) had significantly higher IGF-1 levels compared to never users.</p> <p>Conclusion</p> <p>This is the first study to highlight the long term effects of OC use after cessation on IGF-1 levels among premenopausal women, which previously were thought to be transitory. Future studies of past use and IGF-1 levels are required and must consider age/timing of use and type/generation of OC used. Additional studies are needed to confirm the potential mediation of IGF-1 levels in the links between OC use and health outcomes.</p

    Incentivizing the Dynamic Workforce: Learning Contracts in the Gig-Economy

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    In principal-agent models, a principal offers a contract to an agent to perform a certain task. The agent exerts a level of effort that maximizes her utility. The principal is oblivious to the agent's chosen level of effort, and conditions her wage only on possible outcomes. In this work, we consider a model in which the principal is unaware of the agent's utility and action space. She sequentially offers contracts to identical agents, and observes the resulting outcomes. We present an algorithm for learning the optimal contract under mild assumptions. We bound the number of samples needed for the principal obtain a contract that is within Ï”\epsilon of her optimal net profit for every Ï”>0\epsilon>0

    Correction to: Two years later: Is the SARS-CoV-2 pandemic still having an impact on emergency surgery? An international cross-sectional survey among WSES members

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    Background: The SARS-CoV-2 pandemic is still ongoing and a major challenge for health care services worldwide. In the first WSES COVID-19 emergency surgery survey, a strong negative impact on emergency surgery (ES) had been described already early in the pandemic situation. However, the knowledge is limited about current effects of the pandemic on patient flow through emergency rooms, daily routine and decision making in ES as well as their changes over time during the last two pandemic years. This second WSES COVID-19 emergency surgery survey investigates the impact of the SARS-CoV-2 pandemic on ES during the course of the pandemic. Methods: A web survey had been distributed to medical specialists in ES during a four-week period from January 2022, investigating the impact of the pandemic on patients and septic diseases both requiring ES, structural problems due to the pandemic and time-to-intervention in ES routine. Results: 367 collaborators from 59 countries responded to the survey. The majority indicated that the pandemic still significantly impacts on treatment and outcome of surgical emergency patients (83.1% and 78.5%, respectively). As reasons, the collaborators reported decreased case load in ES (44.7%), but patients presenting with more prolonged and severe diseases, especially concerning perforated appendicitis (62.1%) and diverticulitis (57.5%). Otherwise, approximately 50% of the participants still observe a delay in time-to-intervention in ES compared with the situation before the pandemic. Relevant causes leading to enlarged time-to-intervention in ES during the pandemic are persistent problems with in-hospital logistics, lacks in medical staff as well as operating room and intensive care capacities during the pandemic. This leads not only to the need for triage or transferring of ES patients to other hospitals, reported by 64.0% and 48.8% of the collaborators, respectively, but also to paradigm shifts in treatment modalities to non-operative approaches reported by 67.3% of the participants, especially in uncomplicated appendicitis, cholecystitis and multiple-recurrent diverticulitis. Conclusions: The SARS-CoV-2 pandemic still significantly impacts on care and outcome of patients in ES. Well-known problems with in-hospital logistics are not sufficiently resolved by now; however, medical staff shortages and reduced capacities have been dramatically aggravated over last two pandemic years
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