Environmental variability, reliability of information and the timing of migration

The timing of migration and migratory steps is highly relevant for fitness. Because environmental conditions vary between years, the optimal time for migration varies accordingly. Therefore, migratory animals could clearly benefit from acquiring information as to when it is the best time to migrate in a specific year. Thus, environmental predictability and variability are fundamental characteristics of migration systems but their relationship and consequence for migratory progression has remained unexplored. We develop a simple dynamic model to identify the optimal migration behaviour in environments that differ in predictability, variability and the number of intermediate stop-over sites. Our results indicate that higher predictability along migration routes enables organisms to better time migration when phenology deviates from its long-term average and thus, increases fitness. Information is particularly valuable in highly variable environments and in the final migration-step, i.e. before the destination. Furthermore, we show that a general strategy for obtaining information in relatively uninformative but variable environments is using intermediate stop-over sites that enable migrants to better predict conditions ahead. Our study contributes to a better understanding of the relationship between animal movement and environmental predictability—an important, yet underappreciated factor that strongly influences migratory progression.

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Reduced phenotypic plasticity evolves in less predictable environments

10.1101/2020.07.07.191320 ◽

2020 ◽

Author(s):

Christelle Leung ◽

Marie Rescan ◽

Daphné Grulois ◽

Luis-Miguel Chevin

Keyword(s):

Phenotypic Plasticity ◽

Dunaliella Salina ◽

Extinction Risk ◽

Morphological Plasticity ◽

Population Responses ◽

Selective Pressures ◽

Environmental Predictability ◽

Variable Environments ◽

Plastic Responses

AbstractPhenotypic plasticity is a prominent mechanism for coping with variable environments, and a key determinant of extinction risk. Evolutionary theory predicts that phenotypic plasticity should evolve to lower levels in environments that fluctuate less predictably, because they induce mismatches between plastic responses and selective pressures. However this prediction is difficult to test in nature, where environmental predictability is not controlled. Here, we exposed 32 lines of the halotolerant microalga Dunaliella salina to ecologically realistic, randomly fluctuating salinity, with varying levels of predictability, for 500 generations. We found that morphological plasticity evolved to lower levels in lines that experienced less predictable environments. Evolution of plasticity mostly concerned phases with slow population growth, rather than the exponential phase where microbes are typically phenotyped. This study underlines that long-term experiments with complex patterns of environmental change are needed to test theories about population responses to altered environmental predictability, as currently observed under climate change.

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Coral assemblages at higher latitudes favour short-term potential over long-term performance

10.1101/2021.09.29.462350 ◽

2021 ◽

Author(s):

James Cant ◽

James D Reimer ◽

Brigitte Sommer ◽

Katie Cook ◽

Sun W Kim ◽

...

Keyword(s):

Environmental Variability ◽

Climatic Variability ◽

Short Term ◽

Variable Environments ◽

Coral Communities ◽

Long Term Performance ◽

Term Performance ◽

Thermal Variability ◽

Current Exposure

The current exposure of species assemblages to high environmental variability may grant them resilience to future increases in climatic variability. In globally threatened coral reef ecosystems, management seeks to protect resilient reefs within variable environments. Yet, our lack of understanding for the determinants of coral population performance within variable environments hinders forecasting the future reassembly of coral communities. Here, using Integral Projection Models, we compare the short- (i.e., transient) and long-term (i.e., asymptotic) demographic characteristics of tropical and subtropical coral assemblages to evaluate how thermal variability influences the structural composition of coral communities over time. Exploring spatial variation across the dynamics of functionally different competitive, stress-tolerant, and weedy coral assemblages in Australia and Japan, we show that coral assemblages trade-off long-term performance for transient potential in response to thermal variability. We illustrate how coral assemblages can reduce their susceptibility towards environmental variation by exploiting volatile short-term demographic strategies, thus enhancing their persistence within variable environments. However, we also reveal considerable variation across the vulnerability of competitive, stress-tolerant, and weedy coral assemblages towards future increases in thermal variability. In particular, stress-tolerant and weedy corals possess an enhanced capacity for elevating their transient potential in response to environmental variability. Accordingly, despite their current exposure to high thermal variability, future climatic shifts threaten the structural complexity of coral assemblages, derived mostly from competitive coral taxa within highly variable subtropical environments, emulating the degradation expected across global coral communities.

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Cancer Treatment–Induced Bone Loss (CTIBL): State of the Art and Proper Management in Breast Cancer Patients on Endocrine Therapy

Current Treatment Options in Oncology ◽

10.1007/s11864-021-00835-2 ◽

2021 ◽

Vol 22 (5) ◽

Author(s):

Anna Diana ◽

Francesca Carlino ◽

Emilio Francesco Giunta ◽

Elisena Franzese ◽

Luigi Pio Guerrera ◽

...

Keyword(s):

Breast Cancer ◽

Bone Loss ◽

Cancer Treatment ◽

Endocrine Therapy ◽

Aromatase Inhibitors ◽

Bone Health ◽

Optimal Time ◽

Breast Cancer Patients ◽

Antiresorptive Agents

Opinion statementAbout 70–80% of early breast cancer (BC) patients receive adjuvant endocrine therapy (ET) for at least 5 years. ET includes in the majority of cases the use of aromatase inhibitors, as upfront or switch strategy, that lead to impaired bone health. Given the high incidence and also the high prevalence of BC, cancer treatment–induced bone loss (CTIBL) represents the most common long-term adverse event experimented by patients with hormone receptor positive tumours. CTIBL is responsible for osteoporosis occurrence and, as a consequence, fragility fractures that may negatively affect quality of life and survival expectancy. As recommended by main international guidelines, BC women on aromatase inhibitors should be carefully assessed for their fracture risk at baseline and periodically reassessed during adjuvant ET in order to early detect significant worsening in terms of bone health. Antiresorptive agents, together with adequate intake of calcium and vitamin D, should be administered in BC patients during all course of ET, especially in those at high risk of osteoporotic fractures, as calculated by tools available for clinicians. Bisphosphonates, such as zoledronate or pamidronate, and anti-RANKL antibody, denosumab, are the two classes of antiresorptive drugs used in clinical practice with similar efficacy in preventing bone loss induced by aromatase inhibitor therapy. The choice between them, in the absence of direct comparison, should be based on patients’ preference and compliance; the different safety profile is mainly related to the route of administration, although both types of drugs are manageable with due care, since most of the adverse events are predictable and preventable. Despite advances in management of CTIBL, several issues such as the optimal time of starting antiresorptive agents and the duration of treatment remain unanswered. Future clinical trials as well as increased awareness of bone health are needed to improve prevention, assessment and treatment of CTIBL in these long-term survivor patients.

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Long-term outcomes after noncurative endoscopic resection of early gastric cancer: the optimal time for additional endoscopic treatment

Gastrointestinal Endoscopy ◽

10.1016/j.gie.2017.10.004 ◽

2018 ◽

Vol 87 (4) ◽

pp. 1003-1013.e2 ◽

Cited By ~ 20

Author(s):

Mi Young Jeon ◽

Jun Chul Park ◽

Kyu Yeon Hahn ◽

Sung Kwan Shin ◽

Sang Kil Lee ◽

...

Keyword(s):

Gastric Cancer ◽

Early Gastric Cancer ◽

Endoscopic Resection ◽

Endoscopic Treatment ◽

Optimal Time ◽

Long Term Outcomes

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Behavioral effects of the neurotoxin ß-N-methylamino-L-alanine on the mangrove rivulus (Kryptolebias marmoratus) larvae

Journal of Xenobiotics ◽

10.4081/xeno.2018.7820 ◽

2018 ◽

Author(s):

Alessandra Carion ◽

Julie Hétru ◽

Angèle Markey ◽

Victoria Suarez-Ulloa ◽

Silvestre Frédéric

Keyword(s):

Genetic Factors ◽

Prey Capture ◽

Aquatic Ecotoxicology ◽

Low Genetic Diversity ◽

Variable Environments ◽

Maximal Speed ◽

Self Fertilization ◽

Kryptolebias Marmoratus ◽

Mangrove Rivulus

Mangrove rivulus, Kryptolebias marmoratus, is a hermaphrodite fish capable of self-fertilization. This particularity allows to naturally produce highly homozygous and isogenic individuals. Despite the low genetic diversity, rivulus can live in extremely variable environments and adjust its phenotype accordingly. This species represents a unique opportunity to clearly distinguish the genetic and non-genetic factors implicated in adaptation and evolution, such as epigenetic mechanisms. It is thus a great model in aquatic ecotoxicology to investigate the effects of xenobiotics on the epigenome, and their potential long-term impacts. In the present study, we used the mangrove rivulus to investigate the effects of the neurotoxin ß-N-methylamino-L-alanine (BMAA) on larvae behaviors after 7 days exposure to two sub-lethal concentrations. Results show that BMAA can affect the maximal speed and prey capture (trials and failures), suggesting potential impacts on the organism’s fitness.

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The Interval Between Staged Bilateral Total Knee Arthroplasties Does Not Affect Early Complications of the Second Knee or Long-term Function of the First and Second Knees

10.21203/rs.3.rs-1069755/v1 ◽

2021 ◽

Author(s):

Guangqian Shang ◽

Shuai Xiang ◽

Jianjun Guo ◽

Feng Ji ◽

Shuai Yang ◽

...

Keyword(s):

Complication Rate ◽

Optimal Time ◽

Time Interval ◽

Early Complications ◽

Postoperative Function ◽

Term Function ◽

Significant Difference ◽

Patient Reported ◽

Total Knee

Abstract Background: This study explored the optimal time interval between staged bilateral total knee arthroplasty (BTKA) to minimise early complications of the second TKA and maximise long-term function of the first and second knees.Methods: We retrospectively reviewed 266 patients who underwent staged BTKA between 2010 and 2015. Groups 1–4 had time intervals between BTKAs of 1–6, 6–12, 12–18, and 18–24 months, respectively. Demographics, postoperative complications within 90 days of the second TKA, Knee Society Score (KSS), and Western Ontario and McMaster Universities Arthritis Index (WOMAC) score were compared among the groups.Results: In total, 54, 96, 75, and 41 patients were assigned to groups 1–4, respectively. Although group 1 had the highest overall complication rate (11.11%), there was no significant difference in the complication rate among the four groups. Also, no significant differences were found among the four groups in functional and patient-reported outcomes, in either the first or second knee at 5 years postoperatively, including KSS-knee, KSS-function, WOMAC-pain, WOMAC-stiffness, and WOMAC-physical function. The interval between BTKA did not influence complications or the function of the second knee. The TKA type (posterior-stabilised vs. medial-pivot) and age did not correlate significantly with any scores.Conclusions: There was no group difference in early complications of the second TKA, and postoperative function was equivalent between the two knees and did not vary by the interval between surgeries. Our results can help surgeons discuss the timing of the second TKA with patients, which should be based on their own preferences. If patients cannot tolerate severe symptoms in the contralateral knee after the first TKA, the second TKA should be performed as early as possible.

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Evaluation of optimal time and parameters for measuring potentially mineralized nitrogen in soil

Zbornik Matice srpske za prirodne nauke ◽

10.2298/zmspn0815041k ◽

2008 ◽

pp. 41-49

Author(s):

Mirjana Kresovic ◽

Vlado Licina ◽

Svetlana Antic-Mladenovic

Keyword(s):

Early Spring ◽

Optimal Time ◽

Soil Parameters ◽

Anaerobic Incubation ◽

Aerobic Incubation ◽

Brown Forest Soil ◽

Controlled Conditions ◽

Long Term Experiments ◽

Aerobic And Anaerobic

Our research was done on brown forest soil with long-term experiments and with a system of fertilizing which is in use for 40 years. Experiment variants with an increasing dose of nitrogen fertilizer were chosen for this research. Two experiments have been performed: experiment in pots supplied with ammonium nitrate labeled with a stable isotope 15N (11.8%) and experiment in the field. The aim of the research was to establish which plant and soil parameters group (obtained in the controlled conditions and/or in the field) could be considered as reliable for evaluation of aerobic and anaerobic incubation and of the best time for estimation of potentially mineralized nitrogen in soil. According to the determined correlative dependence, it could be concluded that reliability of aerobic incubation should be estimated in October by plant and soil parameters from field, anaerobic incubation should be estimated in early spring (March) by plant and soil parameters, from controlled conditions (pots) and from field.

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Possible Citizens: Migration Enforcement as the Performance of Citizenship in the United Arab Emirates

International Migration Review ◽

10.1177/01979183211054796 ◽

2021 ◽

pp. 019791832110547

Author(s):

Noora Lori

Keyword(s):

United Arab Emirates ◽

Migrant Workers ◽

Citizenship Status ◽

Guest Worker ◽

Common Experience ◽

Boundary Making ◽

Timing Of Migration ◽

Exclusionary Policies ◽

National Boundaries

While most boundary-making studies examine native-born citizens’ opposition to immigration, this article explains why immigrants develop anti-immigrant attitudes. Under what conditions do previous generations of immigrants develop solidarity with newcomers? When might immigrants, instead, police national boundaries and oppose further immigration or naturalization? I argue that under uncertain citizenship status, long-term immigrants are unlikely to develop solidarity with newcomers, despite common experience with exclusionary citizenship policies. Drawing on interviews with naturalization applicants in the United Arab Emirates, this article analyses how policies that unevenly distribute rights and protections to non-citizens structure relationships between immigrant groups. Moving beyond citizen/non-citizen binaries, it calls attention to hierarchies among non-citizens, examining how long-term immigrants with partial and conditional rights police national boundaries to navigate exclusionary policies. When states restrict citizenship, making it a scarce good, immigrants may respond to uncertainty by competing and, thus, limiting access to that good for newcomers. When naturalization is arduous, applicants face pressures to continually perform citizenship to prove that they deserve inclusion. Naturalization applicants lacked citizenship, but they immigrated to the UAE before the establishment of its guest-worker program and claimed Emirati identity by differentiating themselves from “migrant workers.” I show how migration enforcement and boundary-policing factored into their perceptions and performances of what it meant to be a “good” Emirati citizen. Ethnic hierarchies and the timing of migration created distinctions between immigrants eligible for naturalization and those who were not. The mere possibility of inclusion in the citizenry may generate hierarchies between immigrants, precluding solidarity, and encouraging boundary-policing.

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Declines in an abundant aquatic insect, the burrowing mayfly, across major North American waterways

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.1913598117 ◽

2020 ◽

Vol 117 (6) ◽

pp. 2987-2992 ◽

Cited By ~ 12

Author(s):

Phillip M. Stepanian ◽

Sally A. Entrekin ◽

Charlotte E. Wainwright ◽

Djordje Mirkovic ◽

Jennifer L. Tank ◽

...

Keyword(s):

Mississippi River ◽

Animal Movement ◽

Aquatic Insect ◽

Terrestrial Ecosystems ◽

Trophic Levels ◽

Western Lake ◽

Annual Biomass ◽

Emergence Event ◽

Western Lake Erie

Seasonal animal movement among disparate habitats is a fundamental mechanism by which energy, nutrients, and biomass are transported across ecotones. A dramatic example of such exchange is the annual emergence of mayfly swarms from freshwater benthic habitats, but their characterization at macroscales has remained impossible. We analyzed radar observations of mayfly emergence flights to quantify long-term changes in annual biomass transport along the Upper Mississippi River and Western Lake Erie Basin. A single emergence event can produce 87.9 billion mayflies, releasing 3,078.6 tons of biomass into the airspace over several hours, but in recent years, production across both waterways has declined by over 50%. As a primary prey source in aquatic and terrestrial ecosystems, these declines will impact higher trophic levels and environmental nutrient cycling.

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