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Including clover and herb species in grazing forages – effects on milk production, milk processability and milk fatty acid profile of late lactation dairy cows supplemented with grass silage and concentrate
- K. M. McCarthy, N. Walsh, E. Serra, A. G. Fahey, M. B. Lynch, K. M. Pierce, T. M. Boland, H. Sheridan, M. Markiewicz-Keszycka, F. J. Mulligan
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- Journal:
- The Journal of Agricultural Science , First View
- Published online by Cambridge University Press:
- 15 February 2024, pp. 1-13
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Milk production declines as dairy cows enter late lactation, resulting in reduced milk quality and negatively impacting milk processability, such as rennet coagulation time (RCT), milk pH and ethanol stability (ES), leading to seasonality issues for milk processors. Multispecies forages, containing grass, legume and herb species, require lower N inputs and are of interest to dairy farmers. However, little is known about the effect of grazing multispecies forages on milk processability characteristics in late lactation dairy cows. Forty-five autumn-calving dairy cows in late lactation were allocated to 1 of 3 grazing forages; perennial ryegrass (PRG; Lolium perenne), perennial ryegrass and white clover (Trifolium pratense) (PRGWC), and a 6 – species multispecies forage (MULTI) containing perennial ryegrass, timothy (Phleum pratense), white clover, red clover (Trifolium repens), chicory (Cichorium intybus) and plantain (Plantago lanceolata). Cows were allocated 12 kg DM grazed forage and supplemented with a grass – silage TMR and concentrate. Forage DMI was significantly lower for cows grazing PRG. Milk yield increased when cows grazed PRGWC (18.07 kg/d) and MULTI (17.84 kg/d) compared to PRG (16.08 kg/d). Milk RCT (mins) and ES (%) were unaffected by treatment. However, offering cows PRGWC and MULTI increased the concentration of C18:2 cis – 9, 12 and C18:3 cis – 9, 12, 15 in milk compared to PRG. Compared to PRG, grazing forages containing clover and herb species improved milk yield and beneficially altered milk fatty acid profile in late lactation dairy cows without negatively impacting milk processability.
The predictive role of symptoms in COVID-19 diagnostic models: A longitudinal insight
- Olivia Bird, Eva P. Galiza, David Neil Baxter, Marta Boffito, Duncan Browne, Fiona Burns, David R. Chadwick, Rebecca Clark, Catherine A. Cosgrove, James Galloway, Anna L. Goodman, Amardeep Heer, Andrew Higham, Shalini Iyengar, Christopher Jeanes, Philip A. Kalra, Christina Kyriakidou, Judy M. Bradley, Chigomezgo Munthali, Angela M. Minassian, Fiona McGill, Patrick Moore, Imrozia Munsoor, Helen Nicholls, Orod Osanlou, Jonathan Packham, Carol H. Pretswell, Alberto San Francisco Ramos, Dinesh Saralaya, Ray P. Sheridan, Richard Smith, Roy L. Soiza, Pauline A. Swift, Emma C. Thomson, Jeremy Turner, Marianne Elizabeth Viljoen, Paul T. Heath, Irina Chis Ster
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- Journal:
- Epidemiology & Infection / Volume 152 / 2024
- Published online by Cambridge University Press:
- 22 January 2024, e37
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To investigate the symptoms of SARS-CoV-2 infection, their dynamics and their discriminatory power for the disease using longitudinally, prospectively collected information reported at the time of their occurrence. We have analysed data from a large phase 3 clinical UK COVID-19 vaccine trial. The alpha variant was the predominant strain. Participants were assessed for SARS-CoV-2 infection via nasal/throat PCR at recruitment, vaccination appointments, and when symptomatic. Statistical techniques were implemented to infer estimates representative of the UK population, accounting for multiple symptomatic episodes associated with one individual. An optimal diagnostic model for SARS-CoV-2 infection was derived. The 4-month prevalence of SARS-CoV-2 was 2.1%; increasing to 19.4% (16.0%–22.7%) in participants reporting loss of appetite and 31.9% (27.1%–36.8%) in those with anosmia/ageusia. The model identified anosmia and/or ageusia, fever, congestion, and cough to be significantly associated with SARS-CoV-2 infection. Symptoms’ dynamics were vastly different in the two groups; after a slow start peaking later and lasting longer in PCR+ participants, whilst exhibiting a consistent decline in PCR- participants, with, on average, fewer than 3 days of symptoms reported. Anosmia/ageusia peaked late in confirmed SARS-CoV-2 infection (day 12), indicating a low discrimination power for early disease diagnosis.
PMDedu: Assessing the educational needs of startups and academic investigators focused on pediatric medical device development
- Payal Shah, Alexis Snitman, Jennifer McCaney, Lynn M. Rose, David Sheridan, Juan Espinoza Salomon
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- Journal:
- Journal of Clinical and Translational Science / Volume 7 / Issue 1 / 2023
- Published online by Cambridge University Press:
- 25 September 2023, e235
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Background:
The pediatric medical device development (PMDD) process is highly complex, beset by a variety of financial, technical, medical, and regulatory barriers. Startup company innovators and academic investigators often struggle with accessing specialized knowledge relating to regulatory requirements, product development, research, and marketing strategies.
Objectives:The West Coast Consortium for Technology & Innovation in Pediatrics (CTIP) conducted an educational needs assessment to understand knowledge gaps and inform our educational strategy.
Methods:We surveyed a total of 49 medical device startups and 52 academic investigators. Electronic surveys were developed for each group on Qualtrics and focused on manufacturing, regulatory, research, commercialization, and funding. Descriptive statistics were used.
Results:A larger proportion of academic investigator respondents had a clinical background compared to the startup respondents (45% vs. 22%). The biggest barriers for academic investigators were understanding regulatory and safety requirements testing (52%) and finding and obtaining non-dilutive funding was the most difficult (54%). Among startups, understanding clinical research methods and requirements was the biggest barrier (79%).
Conclusion:Startup companies and academic investigators have similar, but not identical, educational needs to better understand the PMD development process. Investigators need more support in identifying funding sources, while startup companies identified an increased need for education on research regulatory topics. These findings can help guide curriculum development as well as opportunities for partnerships between academia and startups.
Modeling the development of cognitive reserve in children: A residual index approach
- Zubin A. Irani, Andrew M. C. Sheridan, Timothy J. Silk, Vicki Anderson, Michael Weinborn, Brandon E. Gavett
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- Journal:
- Journal of the International Neuropsychological Society / Volume 30 / Issue 3 / March 2024
- Published online by Cambridge University Press:
- 05 September 2023, pp. 264-272
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Objective:
To model cognitive reserve (CR) longitudinally in a neurodiverse pediatric sample using a residual index approach, and to test the criterion and construct validity of this index.
Method:Participants were N = 115 children aged 9.5–13 years at baseline (MAge = 10.48 years, SDAge = 0.61), and n = 43 (37.4%) met criteria for ADHD. The CR index represented variance in Matrix Reasoning scores from the WASI that was unexplained by MRI-based brain variables (bilateral hippocampal volumes, total gray matter volumes, and total white matter hypointensity volumes) or demographics (age and sex).
Results:At baseline, the CR index predicted math computation ability (estimate = 0.50, SE = 0.07, p < .001), and word reading ability (estimate = 0.26, SE = 0.10, p = .012). Longitudinally, change in CR over time was not associated with change in math computation ability (estimate = −0.02, SE = 0.03, p < .513), but did predict change in word reading ability (estimate = 0.10, SE = 0.03, p < .001). Change in CR was also found to moderate the relationship between change in word reading ability and white matter hypointensity volume (estimate = 0.10, SE = 0.05, p = .045).
Conclusions:Evidence for the criterion validity of this CR index is encouraging, but somewhat mixed, while construct validity was evidenced through interaction between CR, brain, and word reading ability. Future research would benefit from optimization of the CR index through careful selection of brain variables for a pediatric sample.
Associations of alcohol and cannabis use with change in posttraumatic stress disorder and depression symptoms over time in recently trauma-exposed individuals
- Cecilia A. Hinojosa, Amanda Liew, Xinming An, Jennifer S. Stevens, Archana Basu, Sanne J. H. van Rooij, Stacey L. House, Francesca L. Beaudoin, Donglin Zeng, Thomas C. Neylan, Gari D. Clifford, Tanja Jovanovic, Sarah D. Linnstaedt, Laura T. Germine, Scott L. Rauch, John P. Haran, Alan B. Storrow, Christopher Lewandowski, Paul I. Musey, Phyllis L. Hendry, Sophia Sheikh, Christopher W. Jones, Brittany E. Punches, Michael C. Kurz, Robert A. Swor, Lauren A. Hudak, Jose L. Pascual, Mark J. Seamon, Elizabeth M. Datner, Anna M. Chang, Claire Pearson, David A. Peak, Roland C. Merchant, Robert M. Domeier, Niels K. Rathlev, Paulina Sergot, Leon D. Sanchez, Steven E. Bruce, Mark W. Miller, Robert H. Pietrzak, Jutta Joormann, Diego A. Pizzagalli, John F. Sheridan, Steven E. Harte, James M. Elliott, Ronald C. Kessler, Karestan C. Koenen, Samuel A. McLean, Kerry J. Ressler, Negar Fani
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- Journal:
- Psychological Medicine / Volume 54 / Issue 2 / January 2024
- Published online by Cambridge University Press:
- 13 June 2023, pp. 338-349
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Background
Several hypotheses may explain the association between substance use, posttraumatic stress disorder (PTSD), and depression. However, few studies have utilized a large multisite dataset to understand this complex relationship. Our study assessed the relationship between alcohol and cannabis use trajectories and PTSD and depression symptoms across 3 months in recently trauma-exposed civilians.
MethodsIn total, 1618 (1037 female) participants provided self-report data on past 30-day alcohol and cannabis use and PTSD and depression symptoms during their emergency department (baseline) visit. We reassessed participant's substance use and clinical symptoms 2, 8, and 12 weeks posttrauma. Latent class mixture modeling determined alcohol and cannabis use trajectories in the sample. Changes in PTSD and depression symptoms were assessed across alcohol and cannabis use trajectories via a mixed-model repeated-measures analysis of variance.
ResultsThree trajectory classes (low, high, increasing use) provided the best model fit for alcohol and cannabis use. The low alcohol use class exhibited lower PTSD symptoms at baseline than the high use class; the low cannabis use class exhibited lower PTSD and depression symptoms at baseline than the high and increasing use classes; these symptoms greatly increased at week 8 and declined at week 12. Participants who already use alcohol and cannabis exhibited greater PTSD and depression symptoms at baseline that increased at week 8 with a decrease in symptoms at week 12.
ConclusionsOur findings suggest that alcohol and cannabis use trajectories are associated with the intensity of posttrauma psychopathology. These findings could potentially inform the timing of therapeutic strategies.
A Three-Dimensional Reconstruction Algorithm for Scanning Transmission Electron Microscopy Data from a Single Sample Orientation
- Hamish G. Brown, Philipp M. Pelz, Shang-Lin Hsu, Zimeng Zhang, Ramamoorthy Ramesh, Katherine Inzani, Evan Sheridan, Sinéad M. Griffin, Marcel Schloz, Thomas C. Pekin, Christoph T. Koch, Scott D. Findlay, Leslie J. Allen, Mary C. Scott, Colin Ophus, Jim Ciston
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- Journal:
- Microscopy and Microanalysis / Volume 28 / Issue 5 / October 2022
- Published online by Cambridge University Press:
- 24 June 2022, pp. 1632-1640
- Print publication:
- October 2022
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Increasing interest in three-dimensional nanostructures adds impetus to electron microscopy techniques capable of imaging at or below the nanoscale in three dimensions. We present a reconstruction algorithm that takes as input a focal series of four-dimensional scanning transmission electron microscopy (4D-STEM) data. We apply the approach to a lead iridate, Pb$_2$Ir$_2$O$_7$, and yttrium-stabilized zirconia, Y$_{0.095}$Zr$_{0.905}$O$_2$, heterostructure from data acquired with the specimen in a single plan-view orientation, with the epitaxial layers stacked along the beam direction. We demonstrate that Pb–Ir atomic columns are visible in the uppermost layers of the reconstructed volume. We compare this approach to the alternative techniques of depth sectioning using differential phase contrast scanning transmission electron microscopy (DPC-STEM) and multislice ptychographic reconstruction.
28 - Arts Education and the Learning Sciences
- from Part V - Learning Disciplinary Knowledge
- Edited by R. Keith Sawyer, University of North Carolina, Chapel Hill
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- Book:
- The Cambridge Handbook of the Learning Sciences
- Published online:
- 14 March 2022
- Print publication:
- 07 April 2022, pp 560-578
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Summary
Learning in the arts is distinct from most other subjects for three reasons. First, the arts are centrally a representational domain and learning in the arts involves becoming aware of how representational choices communicate meaning to different audiences. Second, form and meaning are integrated; artistic representations are saturated with meaning, and subtle variations are consequential to that meaning. Third, work in the arts involves examining identify and culture, because artistic cognition is intertwined with both. This chapter argues that these three distinct features of arts learning have implications for our understanding of learning more generally. The chapter reviews four types of research: (1) how the arts have been studied in educational settings; (2) how learning occurs in different arts including music and visual arts; (3) the key features of arts learning: the role of the audience, critique, authentic assessment, and role taking; (4) how an arts-based perspective can contribute to our understanding of learning in all subjects.
Prior differences in previous trauma exposure primarily drive the observed racial/ethnic differences in posttrauma depression and anxiety following a recent trauma
- N. G. Harnett, N. M. Dumornay, M. Delity, L. D. Sanchez, K. Mohiuddin, P. I. Musey, Jr., M. J. Seamon, S. A. McLean, R. C. Kessler, K. C. Koenen, F. L. Beaudoin, L. A. M. Lebois, S. J. H. van Rooij, N. A. Sampson, V. Michopoulos, J. L. Maples-Keller, J. P. Haran, A. B. Storrow, C. Lewandowski, P. L. Hendry, S. Sheikh, C. W. Jones, B. E. Punches, M. C. Kurz, R. A. Swor, M. E. McGrath, L. A. Hudak, J. L. Pascual, S. L. House, X. An, J. S. Stevens, T. C. Neylan, T. Jovanovic, S. D. Linnstaedt, L. T. Germine, E. M. Datner, A. M. Chang, C. Pearson, D. A. Peak, R. C. Merchant, R. M. Domeier, N. K. Rathlev, B. J. O'Neil, P. Sergot, S. E. Bruce, M. W. Miller, R. H. Pietrzak, J. Joormann, D. M. Barch, D. A. Pizzagalli, J. F. Sheridan, J. W. Smoller, B. Luna, S. E. Harte, J. M. Elliott, K. J. Ressler
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- Journal:
- Psychological Medicine / Volume 53 / Issue 6 / April 2023
- Published online by Cambridge University Press:
- 31 January 2022, pp. 2553-2562
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Background
Racial and ethnic groups in the USA differ in the prevalence of posttraumatic stress disorder (PTSD). Recent research however has not observed consistent racial/ethnic differences in posttraumatic stress in the early aftermath of trauma, suggesting that such differences in chronic PTSD rates may be related to differences in recovery over time.
MethodsAs part of the multisite, longitudinal AURORA study, we investigated racial/ethnic differences in PTSD and related outcomes within 3 months after trauma. Participants (n = 930) were recruited from emergency departments across the USA and provided periodic (2 weeks, 8 weeks, and 3 months after trauma) self-report assessments of PTSD, depression, dissociation, anxiety, and resilience. Linear models were completed to investigate racial/ethnic differences in posttraumatic dysfunction with subsequent follow-up models assessing potential effects of prior life stressors.
ResultsRacial/ethnic groups did not differ in symptoms over time; however, Black participants showed reduced posttraumatic depression and anxiety symptoms overall compared to Hispanic participants and White participants. Racial/ethnic differences were not attenuated after accounting for differences in sociodemographic factors. However, racial/ethnic differences in depression and anxiety were no longer significant after accounting for greater prior trauma exposure and childhood emotional abuse in White participants.
ConclusionsThe present findings suggest prior differences in previous trauma exposure partially mediate the observed racial/ethnic differences in posttraumatic depression and anxiety symptoms following a recent trauma. Our findings further demonstrate that racial/ethnic groups show similar rates of symptom recovery over time. Future work utilizing longer time-scale data is needed to elucidate potential racial/ethnic differences in long-term symptom trajectories.
Early adversity and children's emotion regulation: Differential roles of parent emotion regulation and adversity exposure
- Helen M. Milojevich, Laura Machlin, Margaret A. Sheridan
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- Development and Psychopathology / Volume 32 / Issue 5 / December 2020
- Published online by Cambridge University Press:
- 11 January 2021, pp. 1788-1798
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Exposure to early life adversity (ELA) is associated with increased rates of psychopathology and poor physical health. The present study builds on foundational work by Megan Gunnar identifying how ELA results in poor long-term outcomes through alterations in the stress response system, leading to major disruptions in emotional and behavioral regulation. Specifically, the present study tested the direct effects of ELA against the role of parent socialization to shed light on the mechanisms by which ELA leads to emotion regulation deficits. Children ages 4–7 years (N = 64) completed interviews about their experiences of deprivation and threat, a fear conditioning and extinction paradigm, and an IQ test. Parents of the children completed questionnaires regarding their own emotion regulation difficulties and psychopathology, their children's emotion regulation, and child exposure to adversity. At the bivariate level, greater exposure to threat and parental difficulties with emotion regulation were associated with poorer emotion regulation in children, assessed both via parental report and physiologically. In models where parental difficulties with emotion regulation, threat, and deprivation were introduced simultaneously, regression results indicated that parental difficulties with emotion regulation, but not deprivation or threat, continued to predict children's emotion regulation abilities. These results suggest that parental socialization of emotion is a robust predictor of emotion regulation tendencies in children exposed to early adversity.
Burden of respiratory syncytial virus hospitalisation among infants born at 32–35 weeks' gestational age in the Northern Hemisphere: pooled analysis of seven studies
- M. Lanari, E.J. Anderson, M. Sheridan-Pereira, X. Carbonell-Estrany, B. Paes, B.S. Rodgers-Gray, J. R. Fullarton, E. Grubb, M. Blanken
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- Journal:
- Epidemiology & Infection / Volume 148 / 2020
- Published online by Cambridge University Press:
- 17 August 2020, e170
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To provide comprehensive information on the epidemiology and burden of respiratory syncytial virus hospitalisation (RSVH) in preterm infants, a pooled analysis was undertaken of seven multicentre, prospective, observational studies from across the Northern Hemisphere (2000–2014). Data from all 320–356 weeks' gestational age (wGA) infants without comorbidity were analysed. RSVH occurred in 534/14 504 (3.7%) infants; equating to a rate of 5.65 per 100 patient-seasons, with the rate in individual wGA groups dependent upon exposure time (P = 0.032). Most RSVHs (60.1%) occurred in December–January. Median age at RSVH was 88 days (interquartile range (IQR): 54–159). Respiratory support was required by 82.0% of infants: oxygen in 70.4% (median 4 (IQR: 2–6) days); non-invasive ventilation in 19.3% (median 3 (IQR: 2–5) days); and mechanical ventilation in 10.2% (median 5 (IQR: 3–7) days). Intensive care unit admission was required by 17.9% of infants (median 6 days (IQR: 2–8) days). Median overall hospital length of stay (LOS) was 5 (IQR: 3–8) days. Hospital resource use was similar across wGA groups except for overall LOS, which was shortest in those born 35 wGA (median 3 vs. 4–6 days for 32–34 wGA; P < 0.001). Strategies to reduce the burden of RSVH in otherwise healthy 32–35 wGA infants are indicated.
Metabolic and endocrine adverse effects of second-generation antipsychotics in children and adolescents: A systematic review of randomized, placebo controlled trials and guidelines for clinical practice
- M. De Hert, M. Dobbelaere, E.M. Sheridan, D. Cohen, C.U. Correll
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- European Psychiatry / Volume 26 / Issue 3 / April 2011
- Published online by Cambridge University Press:
- 16 April 2020, pp. 144-158
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Second-generation antipsychotics (SGA) are being used more often than ever before in children and adolescents with psychotic and a wide range of non-psychotic disorders. Several SGA have received regulatory approval for some paediatric indications in various countries, but off-label use is still frequent. The aim of this paper was to perform a systematic review and critically evaluate the literature on cardiometabolic and endocrine side-effects of SGA in children and adolescents through a Medline/Pubmed/Google Scholar search of randomized, placebo controlled trials of antipsychotics in children and adolescents (<18 years old) until February 2010. In total, 31 randomized, controlled studies including 3595 paediatric patients were identified. A review of these data confirmed that SGA are associated with relevant cardiometabolic and endocrine side-effects, and that children and adolescents have a high liability to experience antipsychotic induced hyperprolactinaemia, weight gain and associated metabolic disturbances. Only weight change data were sufficiently reported to conduct a formal meta-analysis. In 24 trials of 3048 paediatric patients with varying ages and diagnoses, ziprasidone was associated with the lowest weight gain (−0.04 kg, 95% confidence interval [CI]: −0.38 to +0.30), followed by aripiprazole (0.79 kg, 95% CI: 0.54 to 1.04], quetiapine (1.43 kg, 95% CI: 1.17 to 1.69) and risperidone (1.76 kg, 95% CI: 1.27 to 2.25) were intermediate, and olanzapine was associated with weight gain the most (3.45 kg, 95% CI: 2.93 to 3.97). Significant weight gain appeared to be more prevalent in patients with autistic disorder who were also younger and likely less exposed to antipsychotics previously. These data clearly suggest that close screening and monitoring of metabolic side effects is warranted and that the least cardiometabolically problematic agents should be used first whenever possible. A good collaboration between child- and adolescent psychiatrists, general practitioners and paediatricians is essential to maximize overall outcomes and to reduce the likelihood of premature cardiovascular morbidity and mortality.
Alterations in neural circuits underlying emotion regulation following child maltreatment: a mechanism underlying trauma-related psychopathology
- Jessica L. Jenness, Matthew Peverill, Adam Bryant Miller, Charlotte Heleniak, Madeline M. Robertson, Kelly A. Sambrook, Margaret A. Sheridan, Katie A. McLaughlin
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- Journal:
- Psychological Medicine / Volume 51 / Issue 11 / August 2021
- Published online by Cambridge University Press:
- 07 April 2020, pp. 1880-1889
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Background
Disruptions in neural circuits underlying emotion regulation (ER) may be a mechanism linking child maltreatment with psychopathology. We examined the associations of maltreatment with neural responses during passive viewing of negative emotional stimuli and attempts to modulate emotional responses. We investigated whether the influence of maltreatment on neural activation during ER differed across development and whether alterations in brain function mediated the association between maltreatment and a latent general psychopathology (‘p’) factor.
MethodsYouth aged 8–16 years with (n = 79) and without (n = 72) exposure to maltreatment completed an ER task assessing neural responses during passive viewing of negative and neutral images and effortful attempts to regulate emotional responses to negative stimuli. P-factor scores were defined by a bi-factor model encompassing internalizing and externalizing psychopathology.
ResultsMaltreated youth had greater activation in left amygdala and salience processing regions and reduced activation in multiple regions involved in cognitive control (bilateral superior frontal gyrus, middle frontal gyrus, and dorsal anterior cingulate cortex) when viewing negative v. neutral images than youth without maltreatment exposure. Reduced neural recruitment in cognitive control regions mediated the association of maltreatment with p-factor in whole-brain analysis. Maltreated youth exhibited increasing recruitment with age in ventrolateral prefrontal cortex during reappraisal while control participants exhibited decreasing recruitment with age. Findings were similar after adjusting for co-occurring neglect.
ConclusionsChild maltreatment influences the development of regions associated with salience processing and cognitive control during ER in ways that contribute to psychopathology.
Feedback control of flow-induced vibration of a sphere
- T. McQueen, J. Zhao, J. Sheridan, M. C. Thompson
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- Journal:
- Journal of Fluid Mechanics / Volume 889 / 25 April 2020
- Published online by Cambridge University Press:
- 26 February 2020, A30
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The flow-induced vibration of a sphere elastically mounted in the cross-flow direction with imposed feedback rotation was investigated experimentally. The application of rotation provides a means to exercise control over the vibration response of axisymmetric three-dimensional objects. Both the rotational amplitude, which was imposed in proportion to sphere transverse displacement, and the phase of the control signal were varied over a broad parameter space comprising: a non-dimensionalised proportional gain ($0.5\leqslant K_{p}^{\ast }\leqslant 2$); rotation phase ($0^{\circ }\leqslant \unicode[STIX]{x1D719}_{rot}\leqslant 360^{\circ }$), which is the phase between the applied sphere rotation and the transverse displacement; and reduced velocity ($3\leqslant$$U^{\ast }\leqslant 20$). The corresponding Reynolds number range was ($3900\lesssim Re\lesssim 25\,800$). The structural vibration, fluid forces and wake structure were examined to characterise the effect of the imposed rotation. It was found that the rotation not only altered the magnitude of the vibration response, either amplifying or attenuating the response depending on operating conditions, but it also altered the reduced velocity at which vibrations commenced, the vibration frequency and periodicity and significantly altered the phase between the transverse fluid force and displacement. It was possible to almost completely suppress the vibration in the mode I, mode II and mode III transition regimes for imposed rotation over the ranges $90^{\circ }\lesssim$$\unicode[STIX]{x1D719}_{rot}\lesssim 180^{\circ }$, $15^{\circ }\lesssim$$\unicode[STIX]{x1D719}_{rot}\lesssim 135^{\circ }$ and $0^{\circ }\lesssim$$\unicode[STIX]{x1D719}_{rot}\lesssim 120^{\circ }$, respectively. In particular, this could be achieved at effective rotation rates well below those required by using open-loop control (Sareen et al., J. Fluid Mech., vol. 837, 2018, pp. 258–292). Past the peak of mode II, a ‘galloping-like’ response, similar to that reported by Vicente-Ludlam et al. (J. Fluid Mech., vol. 847, 2018, pp. 93–118) for the circular cylinder, was observed with an increase in vibration amplitude of up to 368 % at the highest reduced velocity tested ($U^{\ast }=20$). Particle image velocimetry measurements revealed a change in the timing and spatial position of the streamwise vortex structures with imposed rotation. Contrary to what has been observed for the circular cylinder, however, no de-synchronisation between vortex shedding and sphere motion was observed.
Deprivation and threat, emotion dysregulation, and psychopathology: Concurrent and longitudinal associations
- Helen M. Milojevich, Kate E. Norwalk, Margaret A. Sheridan
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- Journal:
- Development and Psychopathology / Volume 31 / Issue 3 / August 2019
- Published online by Cambridge University Press:
- 24 April 2019, pp. 847-857
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Maltreatment increases risk for psychopathology in childhood and adulthood, thus identifying mechanisms that influence these associations is necessary for future prevention and intervention. Emotion dysregulation resulting from maltreatment is one potentially powerful mechanism explaining risk for psychopathology. This study tests a conceptual model that distinguishes deprivation and threat as distinct forms of exposure with different pathways to psychopathology. Here we operationalize threat as exposure to physical and/or sexual abuse and deprivation as exposure to neglect. We test the hypothesis that threat and deprivation differentially predict use of avoidant strategies and total regulation. Data were drawn from the Longitudinal Studies on Child Abuse and Neglect (LONGSCAN study; N = 866), which followed high-risk children from age 4 to 18. At age 6, children and their parents reported on adversity exposure. Case records documented exposure to abuse and neglect. At 18, adolescents reported on regulation strategies and psychopathology. Regression analyses indicated that greater exposure to threat, but not deprivation, predicted greater use of avoidant strategies in adolescence. Moreover, avoidance partially mediated the longitudinal association between exposure to threat in early childhood and symptoms of internalizing psychopathology in adolescence. Results suggest that abuse and neglect differentially predict regulation strategy use and that regulation strategy use predicts psychopathology.
Grazing multispecies swards improves ewe and lamb performance
- C. Grace, M. B. Lynch, H. Sheridan, S. Lott, R. Fritch, T. M. Boland
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A two-year (2015 and 2016) grazing study was established to compare ewe and lamb performance when grazed on a perennial ryegrass only sward compared to more diverse sward types. In that study four sward types were investigated: a perennial ryegrass (Lolium perenne) only sward receiving 163 kg nitrogen per hectare per year (N/ha/yr) (PRG); a perennial ryegrass and white clover (Trifolium repens) sward receiving 90 kg N/ha/yr (PRGWC); a six species sward (two grasses (perennial ryegrass and timothy (Phleum pratense)), two legumes (white and red clover (Trifolium pratense)) and two herbs (ribwort plantain (Plantago lanceolata) and chicory (Cichorium intybus)) receiving 90 kg N/ha/yr (6S); and a nine species sward containing cocksfoot (Dactylis glomerata), greater birdsfoot trefoil (Lotus pedunculatus) and yarrow (Achillea millefolium) in addition to the six species listed above, receiving 90 kg N/ha/yr (9S). Each sward type was managed as a separate farmlet and stocked with 30 twin-rearing ewes at a stocking rate of 12.5 ewes/ha under rotational grazing management from turnout post-lambing until housing. Lamb live weight was recorded fortnightly and lambs were drafted for slaughter at 45 kg. Ewe live weight and body condition score (BCS) were recorded on five occasions annually. Lamb faecal egg count (FEC) was recorded fortnightly and lambs were treated with anthelmintics when mean lamb FEC per sward type was above 400 eggs per gram. Ewes grazing the 6S and 9S swards had heavier (P < 0.01) live weights and BCS throughout the study than the ewes grazing the PRG sward. Lambs grazing the 6S sward were heavier than lambs grazing all other sward types of 14 weeks old (P < 0.05). Lambs grazing the PRG sward required more days to reach slaughter weight than lambs grazing all other sward types (P < 0.001). Lambs grazing the 6S and 9S swards required fewer anthelmintic treatments than lambs grazing the PRG or PRGWC swards. In conclusion, grazing multispecies swards improved ewe and lamb performance and reduced the requirement for chemical anthelmintics.
The effect of imposed rotary oscillation on the flow-induced vibration of a sphere
- A. Sareen, J. Zhao, J. Sheridan, K. Hourigan, M. C. Thompson
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- Journal:
- Journal of Fluid Mechanics / Volume 855 / 25 November 2018
- Published online by Cambridge University Press:
- 19 September 2018, pp. 703-735
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This experimental study investigates the effect of imposed rotary oscillation on the flow-induced vibration of a sphere that is elastically mounted in the cross-flow direction, employing simultaneous displacement, force and vorticity measurements. The response is studied over a wide range of forcing parameters, including the frequency ratio $f_{R}$ and velocity ratio $\unicode[STIX]{x1D6FC}_{R}$ of the oscillatory forcing, which vary between $0\leqslant f_{R}\leqslant 5$ and $0\leqslant \unicode[STIX]{x1D6FC}_{R}\leqslant 2$. The effect of another important flow parameter, the reduced velocity, $U^{\ast }$, is also investigated by varying it in small increments between $0\leqslant U^{\ast }\leqslant 20$, corresponding to the Reynolds number range of $5000\lesssim Re\lesssim 30\,000$. It has been found that when the forcing frequency of the imposed rotary oscillations, $f_{r}$, is close to the natural frequency of the system, $f_{nw}$, (so that $f_{R}=f_{r}/f_{nw}\sim 1$), the sphere vibrations lock on to $f_{r}$ instead of $f_{nw}$. This inhibits the normal resonance or lock-in leading to a highly reduced vibration response amplitude. This phenomenon has been termed ‘rotary lock-on’, and occurs for only a narrow range of $f_{R}$ in the vicinity of $f_{R}=1$. When rotary lock-on occurs, the phase difference between the total transverse force coefficient and the sphere displacement, $\unicode[STIX]{x1D719}_{total}$, jumps from $0^{\circ }$ (in phase) to $180^{\circ }$ (out of phase). A corresponding dip in the total transverse force coefficient $C_{y\,(rms)}$ is also observed. Outside the lock-on boundaries, a highly modulated amplitude response is observed. Higher velocity ratios ($\unicode[STIX]{x1D6FC}_{R}\geqslant 0.5$) are more effective in reducing the vibration response of a sphere to much lower values. The mode I sphere vortex-induced vibration (VIV) response is found to resist suppression, requiring very high velocity ratios ($\unicode[STIX]{x1D6FC}_{R}>1.5$) to significantly suppress vibrations for the entire range of $f_{R}$ tested. On the other hand, mode II and mode III are suppressed for $\unicode[STIX]{x1D6FC}_{R}\geqslant 1$. The width of the lock-on region increases with an increase in $\unicode[STIX]{x1D6FC}_{R}$. Interestingly, a reduction of VIV is also observed in non-lock-on regions for high $f_{R}$ and $\unicode[STIX]{x1D6FC}_{R}$ values. For a fixed $\unicode[STIX]{x1D6FC}_{R}$, when $U^{\ast }$ is progressively increased, the response of the sphere is very rich, exhibiting characteristically different vibration responses for different $f_{R}$ values. The phase difference between the imposed rotary oscillation and the sphere displacement $\unicode[STIX]{x1D719}_{rot}$ is found to be crucial in determining the response. For selected $f_{R}$ values, the vibration amplitude increases monotonically with an increase in flow velocity, reaching magnitudes much higher than the peak VIV response for a non-rotating sphere. For these cases, the vibrations are always locked to the forcing frequency, and there is a linear decrease in $\unicode[STIX]{x1D719}_{rot}$. Such vibrations have been termed ‘rotary-induced vibrations’. The wake measurements in the cross-plane $1.5D$ downstream of the sphere position reveal that the sphere wake consists of vortex loops, similar to the wake of a sphere without any imposed rotation; however, there is a change in the timing of vortex formation. On the other hand, for high $f_{R}$ values, there is a reduction in the streamwise vorticity, presumably leading to a decreased total transverse force acting on the sphere and resulting in a reduced response.
Experimental investigation of flow-induced vibration of a sinusoidally rotating circular cylinder
- K. W. L. Wong, J. Zhao, D. Lo Jacono, M. C. Thompson, J. Sheridan
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- Journal:
- Journal of Fluid Mechanics / Volume 848 / 10 August 2018
- Published online by Cambridge University Press:
- 05 June 2018, pp. 430-466
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The present experimental investigation characterises the dynamic response and wake structure of a sinusoidally rotating circular cylinder with a low mass ratio (defined as the ratio of the total oscillating mass to the displaced fluid mass) undergoing cross-stream flow-induced vibration (FIV). The study covers a wide parameter space spanning the forcing rotary oscillation frequency ratio $0\leqslant f_{r}^{\ast }\leqslant 4.5$ and the forcing rotation speed ratio $0\leqslant \unicode[STIX]{x1D6FC}_{r}^{\ast }\leqslant 2.0$, at reduced velocities associated with the vortex-induced vibration (VIV) upper and lower amplitude response branches. Here, $f_{r}^{\ast }=f_{r}/f_{nw}$ and $\unicode[STIX]{x1D6FC}_{r}^{\ast }=\unicode[STIX]{x1D6FA}_{o}D/(2U)$, where $f_{r}$ is the forcing rotary oscillation frequency, $f_{nw}$ is the natural frequency of the system in quiescent fluid (water), $\unicode[STIX]{x1D6FA}_{o}$ is the peak angular rotation speed, $D$ is the cylinder diameter and $U$ is the free-stream velocity; the reduced velocity is defined by $U^{\ast }=U/(\,f_{nw}D)$. The fluid–structure system was modelled using a low-friction air-bearing system in conjunction with a free-surface recirculating water channel, with axial rotary motion provided by a microstepping motor. The cylinder was allowed to vibrate with only one degree of freedom transverse to the oncoming free-stream flow. It was found that in specific ranges of $f_{r}^{\ast }$, the body vibration frequency may deviate from that seen in the non-rotating case and lock onto the forcing rotary oscillation frequency or its one-third subharmonic. The former is referred to as the ‘rotary lock-on’ (RLO) region and the latter as the ‘tertiary lock-on’ (TLO) region. Significant increases in the vibration amplitude and suppression of VIV could both be observed in different parts of the RLO and TLO regions. The peak amplitude response in the case of $U^{\ast }=5.5$ (upper branch) was observed to be $1.2D$, an increase of approximately $50\,\%$ over the non-rotating case, while in the case of $U^{\ast }=8.0$ (lower branch), the peak amplitude response was $2.2D$, a remarkable increase of $270\,\%$ over the non-rotating case. Notably, the results showed that the amplitude responses at moderate Reynolds numbers ($Re=UD/\unicode[STIX]{x1D708}=2060$ and $2940$, where $\unicode[STIX]{x1D708}$ is the kinematic viscosity of the fluid) in the present study showed significant differences from those of a previous low-Reynolds-number ($Re=350$) numerical study at similar reduced velocities by Du & Sun (Phys. Fluids, vol. 14 (8), 2015, pp. 2767–2777). Remarkably, in an additional study examining the cylinder vibration as a function of $U^{\ast }$ while the fixed forcing rotary oscillation parameters were kept constant at $(f_{r}^{\ast },\unicode[STIX]{x1D6FC}_{r}^{\ast })=(1.0,1.0)$, the cylinder experienced substantially larger oscillations than in the non-rotating case, and a rotation-induced galloping response was observed for $U^{\ast }>12$, where the amplitude increased monotonically to reach approximately $3.0D$ at the highest reduced velocity ($U^{\ast }=20$) tested. Furthermore, new wake modes were identified in the RLO and TLO regions using particle image velocimetry measurements at selected points in the $f_{r}^{\ast }-\unicode[STIX]{x1D6FC}_{r}^{\ast }$ parameter space.
Experimental investigation of in-line flow-induced vibration of a rotating circular cylinder
- J. Zhao, D. Lo Jacono, J. Sheridan, K. Hourigan, M. C. Thompson
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- Journal:
- Journal of Fluid Mechanics / Volume 847 / 25 July 2018
- Published online by Cambridge University Press:
- 25 May 2018, pp. 664-699
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This study experimentally investigates the in-line flow-induced vibration (FIV) of an elastically mounted circular cylinder under forced axial rotation in a free stream. The present experiments characterise the structural vibration, fluid forces and wake structure of the fluid–structure system at a low mass ratio (the ratio of the total mass to the displaced fluid mass) over a wide parameter space spanning the reduced velocity range $5\leqslant U^{\ast }\leqslant 32$ and the rotation rate range $0\leqslant \unicode[STIX]{x1D6FC}\leqslant 3.5$ , where $U^{\ast }=U/(\,f_{nw}D)$ and $\unicode[STIX]{x1D6FC}=|\unicode[STIX]{x1D6FA}|D/(2U)$ , with $U$ the free-stream velocity, $D$ the cylinder outer diameter, $f_{nw}$ the natural frequency of the system in quiescent water and $|\unicode[STIX]{x1D6FA}|$ the angular velocity of the cylinder rotation. The corresponding Reynolds number (defined by $Re=UD/\unicode[STIX]{x1D708}$ , with $\unicode[STIX]{x1D708}$ the kinematic viscosity of the fluid) was varied over the interval $1349\leqslant Re\leqslant 8624$ , where it is expected that the FIV response is likely to be relatively insensitive to the Reynolds number. The fluid–structure system was modelled using a low-friction air-bearing system in conjunction with a free-surface water-channel facility. Three vibration regions that exhibited vortex-induced vibration (VIV) synchronisation, rotation-induced galloping and desynchronised responses were observed. In both the VIV synchronisation and rotation-induced galloping regions, significant cylinder vibration was found to be correlated with wake–body synchronisation within the rotation rate range $2.20\lesssim \unicode[STIX]{x1D6FC}\lesssim 3.15$ . Of significant interest, the frequency of the streamwise fluid force could be modulated by the imposed rotation to match that of the transverse lift force, resulting in harmonic synchronisation. Measurements using the particle image velocimetry (PIV) technique were performed to identify the wake structure. Interestingly, the imposed rotation can cause regular vortex shedding in in-line FIV at rotation rates that see suppression of the Bénard–von-Kármán vortex shedding in the case of a rigidly mounted cylinder ( $\unicode[STIX]{x1D6FC}\gtrsim 1.75$ ). There is a monotonic increase in the drag coefficient with rotation rate beyond $\unicode[STIX]{x1D6FC}=2$ for a non-oscillating rotating cylinder. This suggests that the mechanism for sustaining the large rotation-induced galloping oscillations at higher $\unicode[STIX]{x1D6FC}$ is due to a combination of aerodynamic forcing from the locked induced vortex shedding associated with the oscillations, assisted by aerodynamic forcing, evaluated using quasi-steady theory.
Vortex-induced vibrations of a sphere close to a free surface
- A. Sareen, J. Zhao, J. Sheridan, K. Hourigan, M. C. Thompson
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- Journal:
- Journal of Fluid Mechanics / Volume 846 / 10 July 2018
- Published online by Cambridge University Press:
- 11 May 2018, pp. 1023-1058
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Results are presented from an experimental investigation into the effects of proximity to a free surface on vortex-induced vibration (VIV) experienced by fully and semi-submerged spheres that are free to oscillate in the cross-flow direction. The VIV response is studied over a wide range of reduced velocities: $3\leqslant U^{\ast }\leqslant 20$ , covering the mode I, mode II and mode III resonant response branches and corresponding to the Reynolds number range of $5000\lesssim Re\lesssim 30\,000$ . The normalised immersion depth of the sphere is varied in small increments over the range $0\leqslant h^{\ast }\leqslant 1$ for the fully submerged case and $0\leqslant h^{\ast }\leqslant -0.75$ for the semi-submerged case. It is found that for a fully submerged sphere, the vibration amplitude decreases monotonically and gradually as the immersion ratio is decreased progressively, with a greater influence on the mode II and III parts of the response curve. The synchronisation regime becomes narrower as $h^{\ast }$ is decreased, with the peak saturation amplitude occurring at progressively lower reduced velocities. The peak response amplitude decreases almost linearly over the range of $0.5\leqslant h^{\ast }\leqslant 0.185$ , beyond which the peak response starts increasing almost linearly. The trends in the total phase, $\unicode[STIX]{x1D719}_{total}$ , and the vortex phase, $\unicode[STIX]{x1D719}_{vortex}$ , reveal that the mode II response occurs for progressively lower $U^{\ast }$ values with decreasing $h^{\ast }$ . On the other hand, when the sphere pierces the free surface, there are two regimes with different characteristic responses. In regime $\text{I}$ ( $-0.5<h^{\ast }<0$ ), the synchronisation region widens and the vibration amplitude increases, surprisingly becoming even higher than for the fully submerged case in some cases, as $h^{\ast }$ decreases. However, in regime $\text{II}$ ( $-0.5\leqslant h^{\ast }\leqslant -0.75$ ), the vibration amplitude decreases with a decrease in $h^{\ast }$ , showing a very sharp reduction beyond $h^{\ast }<-0.65$ . The response in regime II is characterised by two distinct peaks in the amplitude response curve. Careful analysis of the force data and phase information reveals that the two peaks correspond to modes I and II seen for the fully submerged vibration response. This two-peak behaviour is different to the classic VIV response of a sphere under one degree of freedom (1-DOF). The response was found to be insensitive to the Froude number ( $Fr=U/\sqrt{gD}$ , where $U$ is the free-stream velocity, $D$ is the sphere diameter and $g$ is the acceleration due to gravity) in the current range of $0.05\leqslant Fr\leqslant 0.45$ , although higher Froude numbers resulted in slightly lower peak response amplitudes. The wake measurements in the cross-plane $1.5D$ downstream of the rear of the sphere reveal a reduction in the vorticity of the upper vortex of the trailing vortex pair, presumably through diffusion of vorticity into the free surface. For the piercing sphere case, the near-surface vorticity completely diffuses into the free surface, with only the opposite-signed vortex visible in the cross-plane at this downstream position. Interestingly, this correlates with an even higher oscillation amplitude than the fully submerged case. Finally, the effects of immersion ratio and diameter ratio ( $D^{\ast }$ $=$ sphere diameter/support-rod diameter) are quantified, showing care needs to be taken with these factors to avoid unduly influencing VIV predictions.
Vortex-induced vibration of a rotating sphere
- A. Sareen, J. Zhao, D. Lo Jacono, J. Sheridan, K. Hourigan, M. C. Thompson
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- Journal:
- Journal of Fluid Mechanics / Volume 837 / 25 February 2018
- Published online by Cambridge University Press:
- 20 December 2017, pp. 258-292
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Vortex-induced vibration (VIV) of a sphere represents one of the most generic fundamental fluid–structure interaction problems. Since vortex-induced vibration can lead to structural failure, numerous studies have focused on understanding the underlying principles of VIV and its suppression. This paper reports on an experimental investigation of the effect of imposed axial rotation on the dynamics of vortex-induced vibration of a sphere that is free to oscillate in the cross-flow direction, by employing simultaneous displacement and force measurements. The VIV response was investigated over a wide range of reduced velocities (i.e. velocity normalised by the natural frequency of the system): $3\leqslant U^{\ast }\leqslant 18$, corresponding to a Reynolds number range of $5000<Re<30\,000$, while the rotation ratio, defined as the ratio between the sphere surface and inflow speeds, $\unicode[STIX]{x1D6FC}=|\unicode[STIX]{x1D714}|D/(2U)$, was varied in increments over the range of $0\leqslant \unicode[STIX]{x1D6FC}\leqslant 7.5$. It is found that the vibration amplitude exhibits a typical inverted bell-shaped variation with reduced velocity, similar to the classic VIV response for a non-rotating sphere but without the higher reduced velocity response tail. The vibration amplitude decreases monotonically and gradually as the imposed transverse rotation rate is increased up to $\unicode[STIX]{x1D6FC}=6$, beyond which the body vibration is significantly reduced. The synchronisation regime, defined as the reduced velocity range where large vibrations close to the natural frequency are observed, also becomes narrower as $\unicode[STIX]{x1D6FC}$ is increased, with the peak saturation amplitude observed at progressively lower reduced velocities. In addition, for small rotation rates, the peak amplitude decreases almost linearly with $\unicode[STIX]{x1D6FC}$. The imposed rotation not only reduces vibration amplitudes, but also makes the body vibrations less periodic. The frequency spectra revealed the occurrence of a broadband spectrum with an increase in the imposed rotation rate. Recurrence analysis of the structural vibration response demonstrated a transition from periodic to chaotic in a modified recurrence map complementing the appearance of broadband spectra at the onset of bifurcation. Despite considerable changes in flow structure, the vortex phase ($\unicode[STIX]{x1D719}_{vortex}$), defined as the phase between the vortex force and the body displacement, follows the same pattern as for the non-rotating case, with the $\unicode[STIX]{x1D719}_{vortex}$ increasing gradually from low values in Mode I of the sphere vibration to almost $180^{\circ }$ as the system undergoes a continuous transition to Mode II of the sphere vibration at higher reduced velocity. The total phase ($\unicode[STIX]{x1D719}_{total}$), defined as the phase between the transverse lift force and the body displacement, only increases from low values after the peak amplitude response in Mode II has been reached. It reaches its maximum value (${\sim}165^{\circ }$) close to the transition from the Mode II upper plateau to the lower plateau, reminiscent of the behaviour seen for the upper to lower branch transition for cylinder VIV. Hydrogen-bubble visualisations and particle image velocimetry (PIV) performed in the equatorial plane provided further insights into the flow dynamics near the sphere surface. The mean wake is found to be deflected towards the advancing side of the sphere, associated with an increase in the Magnus force. For higher rotation ratios, the near-wake rear recirculation zone is absent and the flow is highly vectored from the retreating side to the advancing side, giving rise to large-scale shedding. For a very high rotation ratio of $\unicode[STIX]{x1D6FC}=6$, for which vibrations are found to be suppressed, a one-sided large-scale shedding pattern is observed, similar to the shear-layer instability one-sided shedding observed previously for a rigidly mounted rotating sphere.