840 results match your criteria hummingbird


Response Properties of Optic Flow Neurons in the Accessory Optic System of Hummingbirds vs. Zebra Finches and Pigeons.

J Neurophysiol 2021 Dec 1. Epub 2021 Dec 1.

Department of Biological Sciences, University of Alberta, Edmonton, AB, Canada.

Optokinetic responses function to maintain retinal image stabilization by minimizing optic flow that occurs during self-motion. The hovering ability of hummingbirds is an extreme example of this behaviour. Optokinetic responses are mediated by direction-selective neurons with large receptive fields in the accessory optic system (AOS) and pretectum. Read More

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December 2021

ATLANTIC POLLINATION: a data set of flowers and interaction with nectar-feeding vertebrates from the Atlantic Forest.

Ecology 2021 Nov 22:e03595. Epub 2021 Nov 22.

Graduação em Ciências Biológicas Bacharelado na Universidade do Estado de Minas Gerais, Rua Sabará 164, CEP, 37900-004, Passos, Minas Gerais, Brasil.

Flowering plant species and their nectar-feeding vertebrates exemplify some of the most remarkable biotic interactions in the Neotropics. In the Brazilian Atlantic Forest, several species of birds (especially hummingbirds), bats and non-flying mammals as well as one lizard feed on nectar, often acting as pollinators and contributing to seed output of flowering plants. We present a dataset containing information on flowering plants visited by nectar-feeding vertebrates sampled at 166 localities in the Brazilian Atlantic Forest. Read More

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November 2021

Effect and correction of control delay in longitudinal dynamics of insect hovering flight.

Authors:
Jie Yao K S Yeo

Phys Rev E 2021 Oct;104(4-1):044410

Department of Mechanical Engineering, National University of Singapore, 9 Engineering Drive 1, Singapore 117575.

Sensor-to-actuator delay is inevitable in any complex control system, be it one for a free-flying insect or a mimicking insectlike robotic flyer. In this work, we analyze the effects of control delay (latency) on the hovering performance of a model insect flyer, as exemplified by the hummingbird hawkmoth Re∼3000, and determine how control coefficients or gains may be modified to ameliorate the adverse effects of latency. The analyses are based on a simplified or reduced dynamic model of the hovering flyer. Read More

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October 2021

Floral traits differentiate pollination syndromes and species but fail to predict the identity of floral visitors to Castilleja.

Am J Bot 2021 Nov 29;108(11):2150-2161. Epub 2021 Oct 29.

Washington State University, School of Biological Sciences, Pullman, WA, 99164, USA.

Premise: Animal pollination is critical to plant reproduction and may cause convergent evolution of pollination syndromes. Pollination syndromes in Castilleja have been distinguished based on floral traits and historical observations of floral visitors. Here we addressed these questions: (1) Can pollination syndromes be distinguished using floral morphological traits or volatile organic compound emissions? (2) Is there significant variation in floral traits within a pollination syndrome at the level of populations or species? (3) Do pollination syndromes predict the most frequent floral visitor to Castilleja?

Methods: Floral traits and visitation were measured for five co-occurring Castilleja species (C. Read More

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November 2021

Rethinking the pollination syndromes in Hymenaea (Leguminosae): the role of anthesis in the diversification.

An Acad Bras Cienc 2021 22;93(4):e20191446. Epub 2021 Oct 22.

Programa de Pós-Graduação em Botânica, Universidade Estadual de Feira de Santana, Av. Transnordestina, s/n, 44036-900 Feira de Santana, BA, Brazil.

Floral traits associated with functional groups of pollinators have been largely employed to understand mechanisms of floral diversification. Hymenaea is a monophyletic legume genus widely recognized to being bat-pollinated, with nocturnal anthesis and copious nectar. The most of species has short-paniculate inflorescences, white and robust flowers, congruent with a bat-pollination syndrome. Read More

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October 2021

[Epigastric pain in "gastric tumors" : The hummingbird among the differential diagnoses].

Chirurg 2021 Oct 19. Epub 2021 Oct 19.

Klinik und Poliklinik für Viszeral‑, Transplantations‑, Thorax- und Gefäßchirurgie, Department für Operative Medizin (DOPM), Universitätsklinikum Leipzig, AöR, Liebigstr. 20, 04103, Leipzig, Deutschland.

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October 2021

Combined CTLA-4 and PD-L1 blockade in patients with chemotherapy-naïve metastatic castration-resistant prostate cancer is associated with increased myeloid and neutrophil immune subsets in the bone microenvironment.

J Immunother Cancer 2021 10;9(10)

Department of Genitourinary Medical Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas, USA

Background: Immune checkpoint therapy (ICT) has low response rates in patients with metastatic castration-resistant prostate cancer (mCRPC), in part due to few T cells in the tumor microenvironment (TME). Anti-cytotoxic T lymphocyte-associated protein 4 (CTLA-4) promotes intratumoral T cell infiltration but induces upregulation of PD-1 and programmed death ligand-1 (PD-L1) within the prostate TME. Combined anti-CTLA-4 plus anti-PD-1 can partly overcome this adaptive resistance and was recently shown to augment responses in patients with mCRPC with measurable disease. Read More

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October 2021

Severity of Downgaze Palsy in the Context of Disease Duration Could Estimate Survival Duration in Patients With Progressive Supranuclear Palsy.

Front Neurol 2021 28;12:736784. Epub 2021 Sep 28.

Department of Ophthalmology, University of Chicago Medicine, Chicago, IL, United States.

It is an unmet need to estimate survival duration for patients with progressive supranuclear palsy (PSP). The objective of this study was to identify factors associated with the survival duration in patients with PSP. We followed up 23 patients with probable PSP-RS (Richardson syndrome) or PSP-P (parkinsonism) in our PSP center until death from 2011 to 2019. Read More

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September 2021

LOW PREVALENCE OF HAEMOSPORIDIANS IN BLOOD AND TISSUE SAMPLES FROM HUMMINGBIRDS.

J Parasitol 2021 Sep;107(5):794-798

Department of Biology, 1600 Holloway Avenue, San Francisco State University, San Francisco, California 94132.

Hummingbirds are vital members of terrestrial ecosystems, and because of their high metabolic requirements, they serve as indicators of ecosystem health. Monitoring the parasitic infections of hummingbirds is thus especially important. Haemosporidians, a widespread group of avian blood parasites, are known to infect hummingbirds, but little is known about the prevalence and diversity of these parasites in hummingbirds. Read More

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September 2021

Hallmarks of response, resistance, and toxicity to immune checkpoint blockade.

Cell 2021 Oct 7;184(21):5309-5337. Epub 2021 Oct 7.

Department of Surgical Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA; Department of Genomic Medicine, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA. Electronic address:

Unprecedented advances have been made in cancer treatment with the use of immune checkpoint blockade (ICB). However, responses are limited to a subset of patients, and immune-related adverse events (irAEs) can be problematic, requiring treatment discontinuation. Iterative insights into factors intrinsic and extrinsic to the host that impact ICB response and toxicity are critically needed. Read More

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October 2021

The disruption of a keystone interaction erodes pollination and seed dispersal networks.

Ecology 2021 Oct 7:e03547. Epub 2021 Oct 7.

Grupo de Ecología de Invasiones, Instituto de Investigaciones en Biodiversidad y Medioambiente (INIBIOMA) - CONICET - Universidad Nacional del Comahue, Bariloche, Argentina.

Understanding the impacts of global change on ecological communities is a major challenge in modern ecology. The gain or loss of particular species and the disruption of key interactions are both consequences and drivers of global change that can lead to the disassembly of ecological networks. We examined whether the disruption of a hummingbird-mistletoe-marsupial mutualism by the invasion of non-native species can have cascading effects on both pollination and seed dispersal networks in the temperate forest of Patagonia, Argentina. Read More

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October 2021

Judge it by its shape: a pollinator-blind approach reveals convergence in petal shape and infers pollination modes in the genus Erythrina.

Am J Bot 2021 09 29;108(9):1716-1730. Epub 2021 Sep 29.

Institut de recherche en biologie végétale and Département de Sciences biologiques, Université de Montréal, 4101 Sherbrooke East, Montréal (QC), H1X 2B2, Canada.

Premise: Pollinators are thought to exert selective pressures on plants, mediating the evolution of convergent floral shape often recognized as pollination syndromes. However, little is known about the accuracy of using petal shape for inferring convergence in pollination mode without a priori pollination information. Here we studied the genus Erythrina L. Read More

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September 2021

A newly described imaging finding for Idiopathic Normal Pressure Hydrocephalus: Can Hummingbird sign contribute to the diagnosis?

Turk J Med Sci 2021 Sep 27. Epub 2021 Sep 27.

Background/aim In this study, we aimed to evaluate whether morphological changes in the mesencephalon which were previously described as a diagnostic tool for progressive supranuclear palsy could be associated also with idiopathic normal pressure hydrocephalus. Materials and Methods Consecutive 52 patients with a possible diagnosis of idiopathic normal pressure hydrocephalus (32 female, mean age 73.6 years) and 40 controls (23 female, mean age 72. Read More

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September 2021

A keystone mutualism promotes resistance to invasion.

J Anim Ecol 2021 Sep 24. Epub 2021 Sep 24.

Grupo de Ecología de Invasiones & Laboratorio Ecotono, Instituto de Investigaciones en Biodiversidad y Medioambiente (INIBIOMA) - CONICET- Universidad Nacional del Comahue, Bariloche, Argentina.

It is not uncommon for one or a few species, and their interactions, to have disproportionate effects on other species in ecological communities. Such keystone interactions might affect how communities respond to the invasion of non-native species by preventing or inhibiting the establishment, spread or impact of non-native species. We explore whether a keystone mutualism among a hummingbird-mistletoe-marsupial promotes ecological resistance to an invasive pollinator, the bumblebee Bombus terrestris, by comparing data collected at sites prior to bumblebee invasion to data collected 11 years after the invasion in sites with and without the keystone mutualism. Read More

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September 2021

Aerodynamic analysis of hummingbird-like hovering flight.

Bioinspir Biomim 2021 Oct 25;16(6). Epub 2021 Oct 25.

Department of Aerospace Engineering, College of Aeronautical Engineering, National University of Sciences and Technology, Islamabad, Pakistan.

Flapping wing micro aerial vehicles are studied as the substitute for fixed and rotary wing micro aerial vehicles because of the advantages such as agility, maneuverability, and employability in confined environments. Hummingbird's sustainable hovering capability inspires many researchers to develop micro aerial vehicles with similar dynamics. In this research, a wing of a ruby-throated hummingbird is modeled as an insect wing using membrane and stiffeners. Read More

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October 2021

Phylogenomics, floral evolution, and biogeography of Lithospermum L. (Boraginaceae).

Authors:
James Cohen

Mol Phylogenet Evol 2021 Sep 20;166:107317. Epub 2021 Sep 20.

Kettering University, Applied Biology, 1700 University Avenue, Flint, MI 48503, USA. Electronic address:

Lithospermum (Boraginaceae), a geographically cosmopolitan medium-sized genus, includes diverse floral morphology, with variation in corolla size and shape and in breeding system. Over the past decade, multiple studies have examined the evolutionary history of Lithospermum, with most utilizing DNA regions from the plastid genome and/or the nuclear ribosomal internal transcribed spacer. These studies have, in general, not resulted in well-resolved and well-supported phylogenies. Read More

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September 2021

Cognitive profiles of patients with mild cognitive impairment due to Alzheimer's versus Parkinson's disease defined using a base rate approach: Implications for neuropsychological assessments.

Alzheimers Dement (Amst) 2021 14;13(1):e12223. Epub 2021 Sep 14.

Department of Neurodegenerative Diseases and Gerontopsychiatry University Hospital of Bonn University of Bonn Bonn Germany.

Introduction: Large studies on cognitive profiles of patients with mild cognitive impairment (MCI) due to Alzheimer's disease (AD-MCI) compared to Parkinson's disease (PD-MCI) are rare.

Methods: Data from two multicenter cohort studies in AD and PD were merged using a unified base rate approach for the MCI diagnosis. Cognitive profiles were compared using scores derived from the Consortium to Establish a Registry for Alzheimer's Disease battery. Read More

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September 2021

Current contrasting population trends among North American hummingbirds.

Sci Rep 2021 09 15;11(1):18369. Epub 2021 Sep 15.

Environment and Climate Change Canada, Wildlife Research Division, National Wildlife Research Centre, 1125 Colonel By Drive, Ottawa, ON, K1S 5B6, Canada.

As pollinators, hummingbirds play a critical role for both the function of ecological communities and in providing ecosystem services for people. To examine the conservation status of North American hummingbirds, we analyzed Breeding Bird Survey data for 8 species and 3 genera from 1970 to 2019 (long-term) and from 2009 to 2019 (short-term, approximately three generations). Among the Selasphorus genus, Allen's, rufous, and broad-tailed hummingbirds have declined since 1970, and the rate of decline increased from 2009 to 2019. Read More

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September 2021

Midbrain area and the hummingbird sign from brain MRI in progressive supranuclear palsy and idiopathic normal pressure hydrocephalus.

J Neuroimaging 2021 Sep 14. Epub 2021 Sep 14.

Department of Surgical Sciences, Radiology, Uppsala University, Uppsala, Sweden.

Background And Purpose: The main radiological finding in progressive supranuclear palsy (PSP) is reduced midbrain volume. Both qualitative (e.g. Read More

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September 2021

CT Morphologic Characteristics and Variant Patterns of Interstitial Pulmonary Fibrosis in Systemic Lupus Erythematosus.

Radiol Cardiothorac Imaging 2021 Aug 12;3(4):e200625. Epub 2021 Aug 12.

Department of Radiology, Children's National Hospital, Washington, DC (D.B.); Department of Radiology and Imaging Sciences (E.A.B.) and Department of Medicine, Division of Pulmonary and Critical Care Medicine (S.V.), Emory University, Atlanta, Ga; Department of Radiology, Massachusetts General Hospital, Boston, Mass (A.S., J.B.A., B.P.L.); and Department of Diagnostic, Molecular and Interventional Radiology, Icahn School of Medicine at Mount Sinai, New York, NY (A.B., M.C.).

Purpose: To assess CT features of pulmonary fibrosis in patients with systemic lupus erythematosus (SLE) and to assess the presence of several distinctive patterns of fibrosis associated with connective tissue disease.

Materials And Methods: A cross-sectional retrospective analysis was performed. An institutional clinical database was queried for the years of 2005-2015 to identify CT examination reports of patients with SLE and fibrotic lung disease, which yielded 50 patients (median age, 49 years; age range, 22-71 years; 46 women). Read More

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The genetic basis of floral mechanical isolation between two hummingbird-pollinated Neotropical understorey herbs.

Mol Ecol 2021 Sep 6. Epub 2021 Sep 6.

Department of Ecology and Evolutionary Biology, University of California, Santa Cruz, Santa Cruz, CA, USA.

Floral divergence can contribute to reproductive isolation among plant lineages, and thus provides an opportunity to study the genetics of speciation, including the number, effect size, mode of action and interactions of quantitative trait loci (QTL). Moreover, flowers represent suites of functionally interrelated traits, but it is unclear to what extent the phenotypic integration of the flower is underlain by a shared genetic architecture, which could facilitate or constrain correlated evolution of floral traits. Here, we examine the genetic architecture of floral morphological traits involved in an evolutionary switch from bill to forehead pollen placement between two species of hummingbird-pollinated Neotropical understorey herbs that are reproductively isolated by these floral differences. Read More

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September 2021

Male-like ornamentation in female hummingbirds results from social harassment rather than sexual selection.

Curr Biol 2021 Oct 26;31(19):4381-4387.e6. Epub 2021 Aug 26.

Department of Ecology, Evolution and Environmental Biology and Center for Integrative Animal Behavior, Columbia University, 1200 Amsterdam Avenue, New York, NY 10027, USA.

Ornamentation is typically observed in sexually mature adults, is often dimorphic in expression, and is most apparent during breeding, supporting a role for sexual selection in its evolution. Yet, increasing evidence suggests that nonsexual social selection may also have a role in the evolution of ornamentation, especially in females. Distinguishing between these alternatives remains challenging because sexual and nonsexual factors may both play important and overlapping roles in trait evolution. Read More

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October 2021

Feather iridescence of hummingbird species varies due to differently organized barbs and barbules.

Biol Lett 2021 08 25;17(8):20210190. Epub 2021 Aug 25.

Surfaces and Thin Films, Zernike Institute for Advanced Materials, University of Groningen, The Netherlands.

Hummingbirds are perhaps the most exquisite bird species because of their prominent iridescence, created by stacks of melanosomes in the feather barbules. The feather colours crucially depend on the nanoscopic dimensions of the melanosome, and the displayed iridescence can distinctly vary, dependent on the spatial organization of the barbs and barbules. We have taken the genus as a model group, with species having feathers that strongly vary in their spatial reflection properties. Read More

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The effect of 12 weeks of mechanical vibration on root resorption: a micro-CT study.

Prog Orthod 2021 Aug 23;22(1):28. Epub 2021 Aug 23.

Department of Orthodontics, Faculty of Dentistry, The University of Sydney, Sydney, Australia.

Objective: The aim was to investigate the effect of mechanical vibration on root resorption with or without orthodontic force application.

Material And Methods: Twenty patients who required maxillary premolar extractions as part of orthodontic treatment were randomly divided into two groups of 10: no-force group and force group. Using a split-mouth procedure, each patient's maxillary first premolar teeth were randomly assigned as either vibration or control side for both groups. Read More

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Clinical Correlation Between Vertical Gaze Palsy and Midbrain Volume in Progressive Supranuclear Palsy.

J Neuroophthalmol 2021 Aug 17. Epub 2021 Aug 17.

Department of Radiology (KB), Massachusetts General Hospital, Boston, Massachusetts; Department of Neuro-Ophthalmology (MB), Beth Israel Deaconess Medical Center, Boston, Massachusetts; Department of Ophthalmology and Visual Sciences (RHK), University of Iowa Hospital and Clinics, Iowa City, Iowa; Iowa City VA Center for the Prevention and Treatment of Visual Loss (RHK), Iowa City VA Health Care System, Iowa City, Iowa; Department of Neurology (A-MW, MS, SHW), Massachusetts General Hospital, Boston, Massachusetts; and School of Optometry (CP), University of California, Berkeley, California.

Background: Supranuclear vertical gaze palsies and slowed vertical saccades are characteristic clinic features of progressive supranuclear palsy (PSP). The "hummingbird sign," reflective of midbrain atrophy, is a classic radiographic sign of PSP. Correlation between eye movement abnormalities and radiographic findings in PSP has been reported previously. Read More

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Colostrum IgA1 antibodies recognize antigens from Helicobacter pylori and prevent cytoskeletal changesin human epithelial cells.

Eur J Immunol 2021 Nov 16;51(11):2641-2650. Epub 2021 Sep 16.

Department of Molecular Biomedicine, Center for Research and Advanced Studies of the National Polytechnic Institute (CINVESTAV-IPN), Mexico City, Mexico.

Helicobacter pylori is a Gram-negative bacterium found on the luminal surface of the gastric mucosa in at least 50% of the world's human population. The protective effect of breastfeeding against H. pylori infection has been extensively reported; however, the mechanisms behind this protection remain poorly understood. Read More

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November 2021

The Hummingbird Collection of the Natural History and Science Museum of the University of Porto (MHNC-UP), Portugal.

Biodivers Data J 2021 23;9:e59913. Epub 2021 Jul 23.

University of Pannonia, Veszprem, Hungary University of Pannonia Veszprem Hungary.

Background: The Hummingbird (Family Trochilidae) Collection of the Natural History and Science Museum of the University of Porto (MHNC-UP) is one of the oldest collections of this family harboured in European museums. Almost 2,000 specimens, that encompass most of the taxonomic diversity of this family, were collected in the late 19 Century. The collection is relevant due its antiquity and because all specimens were bought from the same provider, mainly as mounted specimens, for a Portuguese private collection of Neotropical fauna. Read More

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Pairing automated mark-recapture and social network models to explore the effects of landscape configuration on hummingbird foraging patterns.

Biol Lett 2021 08 4;17(8):20210188. Epub 2021 Aug 4.

Forest Biodiversity Research Network, Corvallis, OR, USA.

Landscape changes can alter pollinator movement and foraging patterns which can in turn influence the demographic processes of plant populations. We leveraged social network models and four fixed arrays of five hummingbird feeders equipped with radio frequency identification (RFID) data loggers to study rufous hummingbird () foraging patterns in a heterogeneous landscape. Using a space-for-time approach, we asked whether forest encroachment on alpine meadows could restrict hummingbird foraging movements and impede resource discovery. Read More

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Durable responses in patients with genitourinary cancers following immune checkpoint therapy rechallenge after moderate-to-severe immune-related adverse events.

J Immunother Cancer 2021 07;9(7)

Department of Genitourinary Medical Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas, USA

Background: Immune checkpoint therapy (ICT) prolongs survival in subsets of patients with cancer but can also trigger immune-related adverse events (irAEs) requiring treatment discontinuation. Recent studies have investigated safety of ICT rechallenge after irAEs, and evidence suggests that rechallenge may be associated with improved antitumor responses. However, data are limited on response duration after ICT rechallenge, particularly after severe irAEs. Read More

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Genetic architecture of floral traits in bee- and hummingbird-pollinated sister species of Aquilegia (columbine).

Evolution 2021 Sep 12;75(9):2197-2216. Epub 2021 Aug 12.

Department of Ecology, Evolutionary, and Marine Biology, University of California Santa Barbara, Santa Babara, California, 93106.

Interactions with animal pollinators have helped shape the stunning diversity of flower morphologies across the angiosperms. A common evolutionary consequence of these interactions is that some flowers have converged on suites of traits, or pollination syndromes, that attract and reward specific pollinator groups. Determining the genetic basis of these floral pollination syndromes can help us understand the processes that contributed to the diversification of the angiosperms. Read More

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September 2021