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"Henderson, S M"
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Autonomous underwater videography and tracking of basking sharks
by
Kerry, C.
,
Whelan, S.
,
Rudd, J.
in
Acoustics
,
Algae
,
Animal Systematics/Taxonomy/Biogeography
2020
Background
Biologging studies have revealed a wealth of information about the spatio-temporal movements of a wide range of vertebrates large enough to carry electronic tracking tags. Advances in autonomous underwater vehicles (AUVs or UAVs) and unmanned aerial vehicles (commonly known as drones), which can carry far larger payloads of sensor technologies, have revealed insights into the environment through which animals travel. Some AUVs have been used to film target animals, but are generally limited to periods as long as a drone operator can actively follow an animal. In the present study, we use an AUV, the REMUS-100 SharkCam, paired with a custom transponder tag attached to the shark, to autonomously follow three basking sharks for a cumulative total of 10.9 h to collect video and environmental data on their sub-surface behaviour. The basking shark is the second largest fish in the world and is endangered globally, but despite being subject to various biologging studies, little is known of this species breeding ecology and their mating grounds remain unknown.
Results
We detail the first successful autonomous tracking of basking sharks, comprising three missions that filmed basking sharks in mid-water and close to benthic habitats. Sharks spent very little time feeding, and travelled relatively close to sandy, rocky and algae-covered benthos. One basking shark was observed defecating. Conspecifics were not observed in the three missions, nor were courtship or breeding behaviours. AUV offset distances for videography were determined iteratively through tracking. These offsets varied depending on the trade-off of between water clarity and proximity of the AUV for obtaining useful video data and directly influencing shark behaviour.
Conclusions
The present study is the first successful use of an AUV to gain insight into the sub-surface behaviour of basking sharks.
Journal Article
Long-term satellite tracking reveals variable seasonal migration strategies of basking sharks in the north-east Atlantic
2017
Animal migration is ubiquitous in nature with individuals within a population often exhibiting varying movement strategies. The basking shark (
Cetorhinus maximus
) is the world’s second largest fish species, however, a comprehensive understanding of their long-term wider-ranging movements in the north-east Atlantic is currently lacking. Seventy satellite tags were deployed on basking sharks over four years (2012–2015) off the west coast of Scotland and the Isle of Man. Data from 28 satellite tags with attachment durations of over 165 days reveal post-summer ranging behaviours. Tagged sharks moved a median minimum straight-line distance of 3,633 km; achieving median displacement of 1,057 km from tagging locations. Tagged individuals exhibited one of three migration behaviours: remaining in waters of UK, Ireland and the Faroe Islands; migrating south to the Bay of Biscay or moving further south to waters off the Iberian Peninsula, and North Africa. Sharks used both continental shelf areas and oceanic habitats, primarily in the upper 50–200 m of the water column, spanning nine geo-political zones and the High Seas, demonstrating the need for multi-national cooperation in the management of this species across its range.
Journal Article
Seasonal changes in basking shark vertical space use in the north-east Atlantic
by
Hall, G
,
Henderson, S M
,
Baxter, J M
in
Annual variations
,
Anthropogenic factors
,
Cetorhinidae
2019
Mobile marine species can exhibit vast movements both horizontally and vertically. Spatial analysis of vertical movements may help improve an understanding of the processes that influence space use. Previously, vertical space use of basking sharks (Cetorhinus maximus) in the north-east Atlantic described movements largely within waters of the continental shelf during summer and autumn months, with few records of detailed vertical behaviour during winter. We use archival satellite telemetry data from 32 basking sharks (12 females, 6 males, and 14 of unknown sex measuring 4–5 m (n = 6), 5–6 m (n = 10), 6–7 m (n = 7), 7–8 m (n = 8), and 8–9 m (n = 1) estimated total length) tracked over 4 years (2012–2015). The satellite tags provided depth and temperature data for a cumulative 4489 days (mean 140 ± 97 days per shark, range 10–292 days) to describe vertical space use and thermal range of basking sharks in the north-east Atlantic. Basking sharks exhibit seasonality in vertical space use, revealing repeated ‘yo-yo’ movement behaviour with periods of occupancy at depths greater than 1000 m in late winter/early spring. Describing seasonal vertical space use in marine megavertebrates can increase knowledge of movements throughout their environment including physiological and morphological constraints to movement, nutrient transfer, and overlap with anthropogenic threats to inform future conservation strategies.
Journal Article
Raisin poisoning in a dog
by
Henderson, S M
,
Brown, P J
,
Penny, D
in
Animals
,
Dog Diseases - chemically induced
,
Dog Diseases - physiopathology
2003
Journal Article
Variation in management of small invasive breast cancers detected on screening in the former South East Thames region: observational study
by
Humphreys, S
,
Henderson, S M
,
Michell, M J
in
Adjuvant chemotherapy
,
Adjuvant treatment
,
Aged
1997
Abstract Objective: To examine the variation in surgical and adjuvant treatment of breast cancer of known histology and detected on screening in a large cohort of patients treated by the surgeons of a health region. Design: Part prospective, part retrospective observational study using the databases of a region's breast screening programme and of the cancer registry. Setting: The former South East Thames region. Subjects: 600 women aged 49–79 who presented during 1991–2 with invasive breast cancer up to 20 mm in diameter that had been detected on screening. These patients were treated by 35 surgeons. Main outcome measures: Mastectomy rate by surgeon and the use of adjuvant treatment (radiotherapy, tamoxifen, and chemotherapy) were compared with risk factors, tumour grade, resection margins, and axillary node status. Results: The mastectomy rate varied between nil and 80%, although the numbers at these extremes were small (0/13 v 8/10). Surgeons operating on more than 20 such cases had a lower mastectomy rate (15%) than surgeons treating fewer cases (23%), but this difference was confounded by variation in casemix. There were also wide variations in mastectomy rates and in axillary sampling rates that were independent of casemix or caseload. There was broad agreement on the use of adjuvant tamoxifen (94%), but few patients received chemotherapy (2.5%). 78 patients (19%) did not receive radiotherapy, including 51 out of 317 patients with unfavourable tumours, and 26 patients did not receive tamoxifen. Whether the patient received adjuvant treatment was more dependent on referral by the surgeon than the risk factors for local recurrence and was independent of caseload. Conclusion: Mastectomy rates for similar tumours vary widely by surgeon independently of casemix or caseload, but surgeons with a higher caseload tend to have a lower mastectomy rate. Omission of postoperative radiotherapy or tamoxifen after conservative treatment is not related to risk factors for local recurrence or caseload. Confidential feedback of treatment profiles to individual surgeons has been used, but when benefit has been established treatment should be guided by evidence based protocol. Key messages In this health region mastectomy rate varied between surgeons, surgeons with higher caseloads tending to be more conservative, but the wide variation in clinical practice was not related to caseload The use of adjuvant tamoxifen in postmenopausal women with invasive breast cancer was high (94%) and the use of adjuvant chemotherapy low (2.5%) Adjuvant radiotherapy after conservative surgery was omitted in 1 in 5 cases, but the omission was not related to risk factors for local recurrence A weekly multidisciplinary meeting is an important safeguard to ensure optimal treatment, and the team should include a radiotherapist or an oncologist When benefit has already been clearly established, treatment should be guided by evidence based protocols and audited by regular site visits
Journal Article
The Impact of Primary Care Dual-Management on Quality of Care
by
Ishani, Areef
,
Charlton, Mary E.
,
Shivapour, Daniel M.
in
Blood pressure
,
Body mass index
,
Body weight
2012
Background: Discontinuity is common in US healthcare. Patients access multiple systems of care and in the nation’s largest integrated healthcare system, Veteran’s Administration (VA) patients frequently use non-VA primary care providers. The impact of this “dual-management” on quality is unknown. The authors’ objective was to identify dual-management and associations with markers of care quality for hypertension and associated conditions. Methods: Data was collected via surveys and chart reviews of primary care patients with hypertension from six VA clinics in Iowa and Minnesota. Clinical measures abstracted included the following: goal blood pressure (BP) and use of guideline-concordant therapy, low-density lipoprotein (LDL) cholesterol, hemoglobin A1C, and body mass index (BMI). Dual-management data was obtained through self-report. Results: Of 189 subjects (mean age = 66), 36% were dual-managed by non-VA providers. There was no difference in hypertension quality of care measures by dual-management status. A total of 51% were at BP goal and 58% were on guideline-concordant therapy. Dual-managed patients were more likely to use thiazide diuretics (43% vs 29%; P = .03) and angiotensin receptor blockers (13% vs 3%; P < .01), but less likely to use angiotensin-converting enzyme inhibitors (43% vs 61%; P = .02). There was no difference in LDL cholesterol (97.1 mg/dl vs 100.1 mg/dl; P = .55), hemoglobin A1C (7% vs 6%; P = .74), or BMI (29.8 vs 30.9; P = .40) for dual-managed versus VA managed patients, respectively. Conclusions: Although dual-management may decrease continuity, VA/private sector dual-management did not impact quality of care, though some medication differences were observed. With the high prevalence of dual-management, future work should further address quality and evaluate redundancy of services.
Journal Article
Refraction of Surface Gravity Waves by Shear Waves
by
Herbers, T. H. C.
,
Elgar, Steve
,
Guza, R. T.
in
Bathymetry
,
Coastal oceanography, estuaries. Regional oceanography
,
Earth, ocean, space
2006
Previous field observations indicate that the directional spread of swell-frequency (nominally 0.1 Hz) surface gravity waves increases during shoreward propagation across the surf zone. This directional broadening contrasts with the narrowing observed seaward of the surf zone and predicted by Snell’s law for bathymetric refraction. Field-observed broadening was predicted by a new model for refraction of swell by lower-frequency (nominally 0.01 Hz) current and elevation fluctuations. The observations and the model suggest that refraction by the cross-shore currents of energetic shear waves contributed substantially to the observed broadening.
Journal Article
Medication Use Among Inner-City Patients After Hospital Discharge: Patient-Reported Barriers and Solutions
by
Kripalani, Sunil, MD, MSc
,
Henderson, Laura E., MS
,
Vaccarino, Viola, MD, PhD
in
Adult
,
African Americans - statistics & numerical data
,
Counseling
2008
OBJECTIVE To better characterize medication-related problems among inner-city patients after hospital discharge and to suggest potential interventions. PATIENTS AND METHODS Between August 9, 2005, and April 3, 2006, we interviewed 84 patients hospitalized with acute coronary syndromes at Grady Memorial Hospital in downtown Atlanta, GA, and contacted them by telephone about 2 weeks later. English-speaking patients who managed their own medications were studied. Patients reported their adherence with filling prescriptions and taking medications after discharge, as well as barriers to and potential enablers of proper medication use. RESULTS Most of the 84 respondents were African American (74 [88%]), male (49 [58%]), and middle-aged (mean age, 54.5 years). Only 40% of patients filled their prescriptions on the day of discharge, 20% filled them 1 or 2 days later, and 18% waited 3 to 9 days; 22% had not filled their prescriptions by the time of the follow-up telephone call (median, 12 days; interquartile range, 8-18 days). Transportation, cost, and wait times at the pharmacy were cited as the main barriers. Many patients reported it was somewhat or very difficult to understand why they were prescribed medications (21%), how to take them (11%), or how to reconcile them with the medications they had been taking before hospitalization (16%). About half the patients (40 [48%]) reported some degree of nonadherence after discharge. Patients noted that several forms of assistance could improve medication use after discharge, including lower medication costs (75%), a follow-up telephone call (68%), transportation to the pharmacy (65%), pharmacist counseling before discharge (64%), and a pillbox (56%). CONCLUSION Patients often delay filling prescriptions and have difficulty understanding medication regimens after hospital discharge. Interventions that reduce medication costs, facilitate transportation, improve medication counseling, and supply such organizing aids as pillboxes might be beneficial.
Journal Article