152 research outputs found

    An observed regime shift in the formation of warm core rings from the gulf stream

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    Ā© The Author(s), 2019. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Gangopadhyay, A., Gawarkiewicz, G., Silva, E. N. S., Monim, M., & Clark, J. An observed regime shift in the formation of warm core rings from the gulf stream. Scientific Reports, 9(1), (2019): 12319-019-48661-9, doi:10.1038/s41598-019-48661-9.We present observational evidence that a significant regime change occurred around the year 2000 in the formation of Warm Core Rings (WCRs) from the Gulf Stream (GS) between 75Ā° and 55Ā°W. The dataset for this study is a set of synoptic oceanographic charts available over the thirty-eight-year period of 1980ā€“2017. The upward regime change shows an increase to 33 WCRs per year during 2000ā€“2017 from an average of 18 WCRs during 1980 to 1999. A seasonal analysis confirms May-June-July as the peak time for WCR births in agreement with earlier studies. The westernmost region (75Ā°-70Ā°W) is least ring-productive, while the region from 65Ā°W to 60Ā°W is most productive. This regime shift around 2000 is detected in WCR formation for all of the four 5-degree wide sub-regions and the whole region (75Ā°-55Ā°W). This might be related to a reduction of the deformation radius for ring formation, allowing unstable meanders to shed more frequent rings in recent years. A number of possible factors resulting in such a regime shift related to the possible changes in reduced gravity, instability, transport of the GS, large-scale changes in the wind system and atmospheric fluxes are outlined, which suggest new research directions. The increase in WCRs has likely had an impact on the marine ecosystem since 2000, a topic worthy for future studies.The authors acknowledge financial supports from NOAA (NA11NOS0120038), NSF (OCE-0815679), SMAST and UMass Dartmouth. GG was supported by NSF under grant OCE-1657853 as well as a Senior Scientist Chair from WHOI. We have benefitted from many discussions on GS system behavior and variability with Tom Rossby, Charlie Flagg, Kathy Donohue, Randy Watts, Peter Cornillon, Magdalena Andres and on WCR identification with Jim Bisagni. The WCR data from Jenifer Clark (co-author) and Roger Pettipas were used to develop the original census. We wish to thank the Editor and two anonymous reviewers for their helpful comments and encouragement to a previous version which improved the focus of this manuscript

    A census of the warm-core rings of the Gulf Stream: 1980-2017

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    Author Posting. Ā© American Geophysical Union, 2020. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Journal of Geophysical Research: Oceans 125(8), (2020): e2019JC016033, doi:10.1029/2019JC016033.A census of Gulf Stream (GS) warmā€core rings (WCRs) is presented based on 38 years (1980ā€“2017) of data. The census documents formation and demise times and locations, and formation size for all 961 WCRs formed in the study period that live for a week or more. A clear regime shift was observed around the Year 2000 and was reported by a subset of authors (Gangopadhyay et al., 2019, https://doi.org/10.1038/s41598-019-48661-9). The WCR formation over the whole region (75ā€“55Ā°W) increased from an average of 18 per year during Regime 1 (1980ā€“1999) to 33 per year during Regime 2 (2000ā€“2017). For geographic analysis formation locations were grouped in four 5Ā° zones between 75Ā°W and 55Ā°W. Seasonally, WCR formations show a significant summer maxima and winter minima, a pattern that is consistent through all zones and both temporal regimes. The lifespan and size distribution show progressively more rings with higher longevity and greater size when formed to the east of 70Ā°W. The average lifespan of the WCRs in all four zones decreased by 20ā€“40% depending on zones and/or seasons from Regime 1 to Regime 2, while the size distribution remained unchanged across regimes. The ring footprint index, a firstā€order signature of impact of the WCRs on the slope, increased significantly (26ā€“90%) for all zones from Regime 1 to Regime 2, with the highest percent increase in Zone 2 (70ā€“65Ā°W). This observational study establishes critical statistical and dynamical benchmarks for validating numerical models and highlights the need for further dynamical understanding of the GSā€ring formation processes.The authors acknowledge financial support from NOAA (NA11NOS0120038), NSF (OCEā€0815679 and OCEā€1851242), and SMAST and UMass Dartmouth. G. G. was supported by NSF under Grant OCEā€1657853 as well as a Senior Scientist Chair from WHOI. We have benefitted from many discussions on Gulf Stream and WCR with Magdalena Andres, Andre Schmidt, Paula Fratantoni, Jon Hare, Wendell Brown, Kathy Donohue, Tom Rossby, Peter Cornillon, and Randy Watts.2020-12-2

    Low-Cost Aquifer Storage and Recovery: Implications for Improving Drinking Water Access for Rural Communities in Coastal Bangladesh

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    Fresh water resources are scarce in rural communities in the southern deltaic plains of Bangladesh where both shallow and deep groundwater is frequently brackish, and fresh water ponds have been increasingly salinized by inundation during storm surges and brackish-water aquaculture. Low-cost aquifer storage and recovery (ASR) schemes were constructed at 13 villages in three coastal districts by developing storage in shallow confined fine to medium sand aquifers overlain by variable thicknesses of silt and clay. A typical ASR scheme consisted of a double-chambered graded sand filtration tank with a volume of 19.5ā€‰ā€‰m3 that feeds filtered pond water to four to six large diameter (d=30.5 or 56 cm) infiltration wells through PVC pipes fitted with stop valves and flow meters. The infiltration wells were completed at 18ā€“31 m below ground and filled with well-sorted gravel capped with a thin layer of fine sand that acts as a second stage filter. Infiltration rates at 13 sites averaged 3ā€‰ā€‰m3/day (range: 3ā€“6ā€‰ā€‰m3/day) over one year of operation. At 11 sites where water was abstracted, the recovery rate ranged from 5 to 40%. The source pond source water frequently had turbidity values of ā‰„100ā€‰ā€‰NTU. After sand filtration, the turbidity is typically 5 NTU. Despite this, clogging management involving frequent (monthly to weekly) manual washing to remove fine materials deposited in the sand filtration tank and the infiltration wells is found to be necessary and effective, with post-manual-washing operational infiltration rates restored to annual average values. E. coli counts in recovered water are greatly reduced compared to raw pond water, although E. coli is still detected in about half of the samples. Arsenic in recovered water was detected to be at level of > 100ā€‰ā€‰Ī¼g/L repeatedly at three sites, suggesting that As risks must be carefully managed and require further investigation

    Characterization of PECVD Silicon Nitride Photonic Components at 532 and 900 nm Wavelength

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    Low temperature PECVD silicon nitride photonic waveguides have been fabricated by both electron beam lithography and 200 mm DUV lithography. Propagation losses and bend losses were both measured at 532 and 900 nm wavelength, revealing sub 1dB/cm propagation losses for cladded waveguides at both wavelengths for single mode operation. Without cladding, propagation losses were measured to be in the 1-3 dB range for 532 nm and remain below 1 dB/cm for 900 nm for single mode waveguides. Bend losses were measured for 532 nm and were well below 0.1 dB per 90 degree bend for radii larger than 10 mu m

    Twelve Tips for Medical Students starting Clinical Placements in the United Kingdom

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    Transitioning from the pre-clinical to clinical years at medical school can be challenging and overwhelming. This paper aims to utilise the experience of healthcare professionals to provide tips for medical students to consider in order to maximise their learning opportunities. Before starting a placement, it is highly encouraged that you familiarise yourself with the curriculum, remember to bring your essentials and dress appropriately. During your placement, ensure good attendance keeping, introduce yourself to the team, manage your time well, engage in self-directed learning, ask questions to other doctors, interact with allied health care professionals and follow the patientā€™s journey from admission to discharge. It is also key to be wary of university requirements, regularly practice history-taking and clinical examination and examination style questions. Prioritise a suitable work-life balance by enjoying hobbies and extra-curricular activities in order to avoid burn-out. These tips should ensure medical students make the most of their clinical placements as well as making it a memorable and enjoyable experience

    The changing nature of shelf-break exchange revealed by the OOI Pioneer Array

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    Author Posting. Ā© The Oceanography Society, 2018. This article is posted here by permission of The Oceanography Society for personal use, not for redistribution. The definitive version was published in Oceanography 31, no. 1 (2018): 60ā€“70, doi:10.5670/oceanog.2018.110.Although the continental shelf and slope south of New England have been the subject of recent studies that address decadal-scale warming and interannual variability of water mass properties, it is not well understood how these changes affect shelf-break exchange processes. In recent years, observations of anomalous shelf and slope conditions obtained from the Ocean Observatories Initiative Pioneer Array and other regional observing programs suggest that onshore intrusions of warm, salty waters are becoming more prevalent. Mean cross-shelf transects constructed from Pioneer Array glider observations collected from April 2014 through December 2016 indicate that slope waters have been warmer and saltier. We examine shelf-break exchange events and anomalous onshore intrusions of warm, salty water associated with warm core rings located near the shelf break in spring 2014 and winter 2017 using observations from the Pioneer Array and other sources. We also describe an additional cross-shelf intrusion of ring water in September 2014 to demonstrate that the occurrence of high-salinity waters extending across the continental shelf is rare. Observations from the Pioneer Array and other sources show warm core ring and Gulf Stream water masses intrude onto the continental shelf more frequently and penetrate further onshore than in previous decades.GG, WZ, RT, and MD were supported by the National Science Foundation under grant OCE-1657853. WZ was also supported by grant OCE-1634965. JP is grateful for the support of the Woods Hole Oceanographic Institution Summer Student Fellow Program. AMM was supported by a grant from the MacArthur Foundation. GG and AMM were also supported by a grant from the van Beuren Charitable Foundation for collection and analysis of hydrographic data collected by the CFRF Shelf Research Fleet

    A survival analysis of the gulf stream warm core rings

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    Author Posting. Ā© American Geophysical Union, 2020. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Journal of Geophysical Research: Oceans 125(10),(2020): e2020JC016507, https://doi.org/10.1029/2020JC016507.Survival of Gulf Stream (GS) warm core rings (WCRs) was investigated using a census consisting of a total of 961 rings formed during the period 1980ā€“2017. Kaplanā€Meier survival probability and Cox hazard proportional models were used for the analysis. The survival analysis was performed for rings formed in four 5Ā° zones between 75Ā° W and 55Ā° W. The radius, latitude, and distance from the shelfā€break of a WCR at formation all had a significant effect on the survival of WCRs. A pattern of higher survival was observed in WCRs formed in Zone 2 (70Ā°ā€“65Ā° W) or Zone 3 (65Ā°ā€“60Ā° W) and then demised in Zone 1 (75Ā°ā€“70Ā° W). Survival probability of the WCRs increased to more than 70% for those formed within a latitude band from 39.5Ā° to 41.5Ā° N. Survival probability is reduced when the WCRs are formed near the New England Seamounts.We are grateful for financial supports from NOAA (NA11NOS0120038), NSF (OCEā€1851242), SMAST, and UMass Dartmouth. G. G. was supported by NSF under grant OCEā€1851261.2021-04-1

    ā€˜We need to share our storiesā€™: the lives of Pakistanis with intellectual disability and their guardians

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    Ā© 2020 MENCAP and International Association of the Scientific Study of Intellectual and Developmental Disabilities and John Wiley & Sons Ltd Introduction: The experiences of Pakistanis with intellectual disabilities (IDs) and their family members have been underexplored empirically. Method: The present study sought to address this gap by understanding the lives of five Special Olympics Pakistan athletes and their guardians through PhotoVoice. Findings: Through thematic analysis, we present the primary theme concerning Pakistan\u27s cultural context that provides an empirical exploration of cultural beliefs about intellectual disability, cultural expectations and support received by people with intellectual disabilities and their guardians. Discussion: We discuss implications for research and practice

    Communication between secondary and primary care following self-harm: are National Institute of Clinical Excellence (NICE) guidelines being met?

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    <p>Abstract</p> <p>Background</p> <p>Most patients contact their general practitioner (GP) following presentation to an Emergency Department (ED) after a self-harm incident, and strategies to help GPs manage these patients include efficient communication between services. The aim of this study was to assess the standard of documentation and communication to primary care from secondary care as recommended by the National Institute of Clinical Excellence (NICE) guidelines on the short-term management of people who self-harm.</p> <p>Methods</p> <p>An audit of medical records (ED and Psychiatric) on people aged 16 years and over who had presented to the ED following self-harm, benchmarked according to government guidelines, was performed. Data were collected over a 4-week period at a general teaching hospital.</p> <p>Results</p> <p>We collected data on 93 consecutive episodes of self-harm; 62% of episodes were communicated to primary care, 58% of these communications were within 24 h and most within 3 days. Patient identifying details and follow-up arrangements were specified in most cases. Communication via psychiatric staff was most detailed. ED clinicians provided few communications and were of limited content. Communication with the patient's GP was not made in half of those cases seen by a mental health specialist.</p> <p>Conclusion</p> <p>Government guidelines are only partially being met. Reliance on communication by ED staff would leave a substantial proportion of patients discharged from the ED with no or minimal communication to primary care. Psychiatric services need to improve the rate of communication to the patient's GP following assessment A national sample of National Health Service (NHS) trusts would establish if this is a problem elsewhere.</p

    Toxicities, kinetics and degradation pathways investigation of ciprofloxacin degradation using iron-mediated H\u3csub\u3e2\u3c/sub\u3eO\u3csub\u3e2\u3c/sub\u3e based advanced oxidation processes

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    Ā© 2018 Institution of Chemical Engineers Ciprofloxacin (CIP) is a widespread emerging water pollutant and thus its removal from aquatic environment is vital. The use of Fe3+/H2O2 and Fe2+/H2O2 resulted in 38 and 64% removal of CIP (8.0 ppm), respectively, within 80 min reaction time (pH 5.8, [H2O2]0 = 80 ppm, and [iron]0 = 20 ppm). Low pH, high temperature, high dose of H2O2 and Fe2+, and low CIP concentration facilitated removal of CIP. The radical scavenger studies proved in situ generated [rad]OH to be involved primarily in the removal of CIP. The effect of temperature was used to estimate enthalpy and activation energies of the removal of CIP. At 800 min reaction time, the Fe2+/H2O2 resulted in 54% mineralization of CIP using 16.0 ppm [CIP]0, 320.0 ppm [H2O2]0, and 40.0 ppm [Fe2+]0. The potential degradation pathways of CIP established from the degradation of CIP by [rad]OH and products evolved was found to be initiated at C6 through the loss of fluoride ion. The acute and chronic toxicities of CIP and its degradation products were estimated with the final product found to be non-toxic. The results suggest that Fe2+/H2O2-mediated AOPs have high potential for degradation as well as toxicity elimination of CIP and its degradation products
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