scholarly journals Brief Communication: Newly developing rift in Larsen C Ice Shelf presents significant risk to stability

2015 ◽  
Vol 9 (1) ◽  
pp. 861-872 ◽  
Author(s):  
D. Jansen ◽  
A. J. Luckman ◽  
A. Cook ◽  
S. Bevan ◽  
B. Kulessa ◽  
...  
Keyword(s):  
At Risk ◽  
Numerical Model ◽  
Significant Risk ◽  
Suture Zone ◽  
Ice Shelf ◽  
Minimum Area ◽  
Shelf Stability ◽  
Near Future

Abstract. An established rift in the Larsen C Ice Shelf, formerly constrained by a suture zone containing marine ice, grew rapidly during 2014 and is likely in the near future to generate the largest calving event since the 1980s and result in a new minimum area for the ice shelf. Here we investigate the recent development of the rift, quantify the projected calving event and, using a numerical model, assess its likely impact on ice shelf stability. We find that the ice front is at risk of becoming unstable when the anticipated calving event occurs.

scholarly journals Brief Communication: Newly developing rift in Larsen C Ice Shelf presents significant risk to stability

2015 ◽  
Vol 9 (3) ◽  
pp. 1223-1227 ◽  
Author(s):  
D. Jansen ◽  
A. J. Luckman ◽  
A. Cook ◽  
S. Bevan ◽  
B. Kulessa ◽  
...  
Keyword(s):  
At Risk ◽  
Numerical Model ◽  
Significant Risk ◽  
Suture Zone ◽  
Ice Shelf ◽  
Minimum Area ◽  
Shelf Stability ◽  
Near Future

Abstract. An established rift in the Larsen C Ice Shelf, formerly constrained by a suture zone containing marine ice, grew rapidly during 2014 and is likely in the near future to generate the largest calving event since the 1980s and result in a new minimum area for the ice shelf. Here we investigate the recent development of the rift, quantify the projected calving event and, using a numerical model, assess its likely impact on ice shelf stability. We find that the ice front is at risk of becoming unstable when the anticipated calving event occurs.

scholarly journals 460. Point-of-Care, In-Home SARS-CoV-2 IgG Antibody Testing to Assess Seroprevalence in At-Risk Health Care Workers

2020 ◽  
Vol 7 (Supplement_1) ◽  
pp. S297-S297
Author(s):  
Eric G Meissner ◽  
Christine Litwin ◽  
Tricia Crocker ◽  
Elizabeth Mack ◽  
Lauren Card
Keyword(s):  
Health Care ◽  
At Risk ◽  
Health Care Workers ◽  
Medical Center ◽  
Point Of Care ◽  
Academic Medical Center ◽  
Significant Risk ◽  
Documented Infection ◽  
Inconclusive Result ◽  
Care Workers

Abstract Background Health care workers are at significant risk for infection with the novel coronavirus SARS-CoV-2. Methods We utilized a point-of-care, lateral flow SARS-CoV-2 IgG immunoassay (RayBiotech) to conduct a seroprevalence study in a cohort of at-risk health care workers (n=339) and normal-risk controls (n=100) employed at an academic medical center. To minimize exposure risk while conducting the study, consents were performed electronically, tests were mailed and then self-administered at home using finger stick blood, and subjects uploaded a picture of the test result while answering an electronic questionnaire. We also validated the assay using de-identified serum samples from patients with PCR-proven SARS-CoV-2 infection. Results Between April 14th and May 6th 2020, 439 subjects were enrolled. Subjects were 68% female, 93% white, and most were physicians (38%) and nurses (27%). In addition, 37% had at least 1 respiratory symptom in the prior month, 34% had cared for a patient with known SARS-CoV-2 infection, 57% and 23% were worried about exposure at work or in the community, respectively, and 5 reported prior documented SARS-CoV-2 infection. On initial testing, 3 subjects had a positive IgG test, 336 had a negative test, and 87 had an inconclusive result. Of those with an inconclusive result who conducted a repeat test (85%), 96% had a negative result. All 3 positive IgG tests were in subjects reporting prior documented infection. Laboratory validation showed that of those with PCR-proven infection more than 13 days prior, 23/30 were IgG positive (76% sensitivity), whereas 1/26 with a negative prior PCR test were seropositive (95% specificity). Repeat longitudinal serologic testing every 30 days for up to 4 times is currently in progress. Conclusion We conducted a contact-free study in the setting of a pandemic to assess SARS-CoV-2 seroprevalence in an at-risk group of health care workers. The only subjects found to be IgG positive were those with prior documented infection, even though a substantial proportion of subjects reported significant potential occupational or community exposure and symptoms that were potentially compatible with SARS-COV-2 infection. Disclosures All Authors: No reported disclosures

scholarly journals Twenty-first century response of Petermann Glacier, northwest Greenland to ice shelf loss

2020 ◽  
pp. 1-11
Author(s):  
Emily A. Hill ◽  
G. Hilmar Gudmundsson ◽  
J. Rachel Carr ◽  
Chris R. Stokes ◽  
Helen M. King
Keyword(s):  
Sea Level ◽  
First Century ◽  
Ice Shelf ◽  
Ice Shelves ◽  
Sea Levels ◽  
Grounding Line ◽  
Global Mean Sea Level ◽  
Near Future ◽  
Global Mean ◽  
Large Sections

Abstract Ice shelves restrain flow from the Greenland and Antarctic ice sheets. Climate-ocean warming could force thinning or collapse of floating ice shelves and subsequently accelerate flow, increase ice discharge and raise global mean sea levels. Petermann Glacier (PG), northwest Greenland, recently lost large sections of its ice shelf, but its response to total ice shelf loss in the future remains uncertain. Here, we use the ice flow model Úa to assess the sensitivity of PG to changes in ice shelf extent, and to estimate the resultant loss of grounded ice and contribution to sea level rise. Our results have shown that under several scenarios of ice shelf thinning and retreat, removal of the shelf will not contribute substantially to global mean sea level (<1 mm). We hypothesize that grounded ice loss was limited by the stabilization of the grounding line at a topographic high ~12 km inland of its current grounding line position. Further inland, the likelihood of a narrow fjord that slopes seawards suggests that PG is likely to remain insensitive to terminus changes in the near future.

Future direction of suicidal risk assessment

2016 ◽  
Vol 33 (S1) ◽  
pp. S68-S68
Author(s):  
H. Blasco-Fontecilla
Keyword(s):  
At Risk ◽  
Suicidal Behavior ◽  
Suicidal Risk ◽  
Sources Of Information ◽  
Future Directions ◽  
Suicide Prediction ◽  
Competing Interest ◽  
Future Direction ◽  
Near Future ◽  
Subjective Reports

Objectiveto explore future directions on the assessment of the risk of suicidal behavior (SB).Methodsnarrative review of current and future methods to improving the assessment of the risk of suicidal behavior (SB).ResultsPredicting future SB is a long-standing goal. Currently, the identification of individuals at risk of SB is based on clinician's subjective reports. Unfortunately, most individuals at risk of SB often do not disclose their suicidal thoughts. In the near future, predicting the risk of SB will be enhanced by: (1) introducing objective, reliable measures – i.e. biomarkers – of suicide risk; (2) selecting the most discriminant variables, and developing more accurate measures – i.e. questionnaires – and models for suicide prediction; (3) incorporating new sources of information – i.e. facebook, online monitoring; (4) applying novel methodological instruments such as data mining, or computer adaptive testing; and, (5) most importantly, combining predictors from different domains (clinical, neurobiological and cognitive).ConclusionsGiven the multi-determined nature of SB, a combination of clinical, neuropsychological, biological, and neuroimaging factors, among other might help overcome current limitations in the prediction of SB. Furthermore, given the complexity of prediction of future SB, currently our efforts should be focused on the prevention of SB.Disclosure of interestThe author has not supplied his declaration of competing interest.

scholarly journals Progressive Degradation of an Ice Rumple in the Thwaites Ice Shelf, Antarctica, as Observed from High-Resolution Digital Elevation Models

2018 ◽  
Vol 10 (8) ◽  
pp. 1236 ◽  
Author(s):  
Seung Hee Kim ◽  
Duk-jin Kim ◽  
Hyun-Cheol Kim
Keyword(s):  
High Resolution ◽  
Surface Deformation ◽  
Surface Expression ◽  
Deformation Model ◽  
Ice Shelf ◽  
Pressure Source ◽  
Viscoelastic Deformation ◽  
Shelf Stability ◽  
Transient Nature ◽  
Elevation Changes

Ice rumples are locally-grounded features of flowing ice shelves, elevated tens of meters above the surrounding surface. These features may significantly impact the dynamics of ice-shelf grounding lines, which are strongly related to shelf stability. In this study, we used TanDEM-X data to construct high-resolution DEMs of the Thwaites ice shelf in West Antarctica from 2011 to 2013. We also generated surface deformation maps which allowed us to detect and monitor the elevation changes of an ice rumple that appeared sometime between the observations of a grounding line of the Thwaites glacier using Double-Differential Interferometric SAR (DDInSAR) in 1996 and 2011. The observed degradation of the ice rumple during 2011–2013 may be related to a loss of contact with the underlying bathymetry caused by the thinning of the ice shelf. We subsequently used a viscoelastic deformation model with a finite spherical pressure source to reproduce the surface expression of the ice rumple. Global optimization allowed us to fit the model to the observed deformation map, producing reasonable estimates of the ice thickness at the center of the pressure source. Our conclusion is that combining the use of multiple high-resolution DEMs and the simple viscoelastic deformation model is feasible for observing and understanding the transient nature of small ice rumples, with implications for monitoring ice shelf stability.

scholarly journals The complex basal morphology and ice dynamics of Nansen Ice Shelf, East Antarctica

2021 ◽  
Author(s):  
Christine F. Dow ◽  
Derek Mueller ◽  
Peter Wray ◽  
Drew Friedrichs ◽  
Alexander L. Forrest ◽  
...  
Keyword(s):  
Large Scale ◽  
Radar Data ◽  
Suture Zone ◽  
East Antarctica ◽  
Strain Rates ◽  
Floating Bodies ◽  
Ice Shelf ◽  
Ice Dynamics ◽  
Complex Morphology ◽  
Hydrostatic Balance

Abstract. Ice shelf dynamics and morphology play an important role in the stability of floating bodies of ice, in turn impacting their ability to buttress upstream grounded ice. We use a combination of satellite-derived data, airborne and ground-based radar data, and oceanographic data collected at the Nansen Ice Shelf in East Antarctica to examine the spatial variations in ice shelf draft, the cause and effects of ice shelf strain rates, and the role of a suture zone driving channelization of ocean water and resulting sub-ice shelf melt and freeze-on. We also use the datasets to assess limitations that may arise from examining only a sub-set of the data, in particular the reliance on hydrostatic balance equations applied to surface digital elevation models to determine ice draft morphology. We find that the Nansen Ice Shelf has highly variable basal morphology driven primarily by the formation of basal crevasses near the onset of floating ice convergence in the suture zone. This complex morphology is reflected in the ice shelf strain rates but not in the calculated hydrostatic balance thickness, which underestimates the scale of vertical and horizontal variability at the ice shelf base. The combination of thinner ice in the channelized suture zone, enhanced melt rates near the ice shelf edge, and complex strain rates driven by ice dynamics and morphology have led to the formation of fractures within the suture zone that have resulted in large-scale calving events. Other Antarctic ice shelves may also have complex morphology, which is not reflected in the satellite data, yet may influence their stability.

Safe Handling of Vaccines

PEDIATRICS ◽  
1991 ◽  
Vol 87 (1) ◽  
pp. 108-112
Author(s):  
Daniel T. Casto ◽  
Philip A. Brunell
Keyword(s):  
At Risk ◽  
Critical Issue ◽  
Invasive Disease ◽  
Cold Chain ◽  
Effective Vaccine ◽  
Vaccine Potency ◽  
The World ◽  
Near Future ◽  
To Receive

The development of safe and effective vaccines for the prevention of infectious diseases associated with high mortality or morbidity is among the most significant accomplishments in medicine. The ultimate goal of eradication of a disease through immunization is an elusive one, having been achieved for only one disease—smallpox. However, a significant reduction in the number of childhood cases of diphtheria, tetanus, pertussis, poliomyelitis, measles, mumps, and rubella has been realized through the use of modern immunizing agents. Recent introduction of vaccines for the prevention of invasive disease caused by Haemophilus influenzae will hopefully provide similar results in the near future. The success of a vaccine in preventing disease is dependent on both the quality of the immunizing agent and the degree to which it is utilized. Obviously, the safest and most effective vaccine in the world will contribute nothing to the decline of a disease without clinicians' efforts to immunize at-risk individuals and without a willingness on the part of these at-risk individuals (or their parents) to receive the vaccine. This critical issue of vaccine utilization deservingly receives attention in the medical literature with some frequency.1,2 Similarly, the quality of vaccines is frequently addressed in publications concerning aspects such as reactogenicity, immunogenicity, and overall efficacy.3-6 One important factor that can influence efficacy, however, is rarely discussed—how vaccines are handled during shipment and storage. Discussions concerning preservation of vaccine potency through proper storage and maintenance of the "cold chain" may seem more pertinent to developing countries of the world, where refrigeration is not readily available and exposure of stored product to extreme environmental conditions can be expected.7-9

scholarly journals A Eurasian Ice-Sheet Study Using A Combined Ice-Sheet/ Ice-Shelf Numerical Model

1990 ◽  
Vol 14 ◽  
pp. 345-345
Author(s):  
Dean R. Lindstrom
Keyword(s):  
Numerical Model ◽  
Mass Loss ◽  
North Atlantic ◽  
Ice Sheet ◽  
The Arctic ◽  
North Atlantic Current ◽  
Ice Shelf ◽  
The North ◽  
The North Atlantic ◽  
Atlantic Current

A numerical model which simultaneously computes grounded and ice-shelf flow was used to develop an equilibrium ice-sheet–ice-shelf system over Eurasia and the Arctic region. Present-day net accumulation rates and mean annual and July temperature values were used as base values for climatic variable specifications. The values were adjusted during the model run to account for changes in the ice-surface elevation and atmospheric CO2 concentration. The model-determined equilibrium ice-sheet configuration was used as input for additional runs to observe what effect removing the Arctic ice shelf and increasing the CO2 concentration from glacial to present-day values has on the ice sheet.At equilibrium, an ice shelf formed over the Arctic Ocean and Greenland and Norwegian seas. Ice easily grounded over the Barents, Kara, East Siberian, and Laptev seas. The grounded ice-sheet profile differs in Europe from most glacial geological reconstructions because the North Atlantic Current effect was not removed from the climatic adjustments. As a result, ice did not extend over the North Sea and onto the British Isles because of the North Atlantic Current's warming effect. Also, the precipitation rate over Europe was too high because of the moisture source the North Atlantic Current carries, and the ice sheet expanded beyond the field-determined ice-sheet margins in the region south-east of Finland.Removing most of the Arctic region's ice-shelf cover had little effect on the grounded ice sheet unless it rested upon a deformable sediment layer. The ice sheet was able to collapse within 10 000 years, however, when the CO2 concentration was gradually increased toward present-day values using the Vostok ice core's CO2 record from the last 18 000 years. Initially, most mass loss resulted from surface melting. Once the thickness decreased enough over some regions for the grounded ice to become ungrounded, however, most mass loss resulted from the ice shelf rapidly transporting the ice to the ice-shelf front and discharging it to the sea.

scholarly journals Can Relict Crevasse Plumes on Antarctic Ice Shelves Reveal a History of Ice-Stream Fluctuation?

1988 ◽  
Vol 11 ◽  
pp. 77-82 ◽  
Author(s):  
D. R. MacAyeal ◽  
R. A. Bindschadler ◽  
K. C. Jezek ◽  
S. Shabtaie
Keyword(s):  
Numerical Model ◽  
Ice Shelf ◽  
Ice Streams ◽  
Ice Shelves ◽  
Stream Discharge ◽  
Ice Stream ◽  
History Of

Configurations of relict surface-crevasse bands and medial moraines that emanate from the shear margins of ice streams are simulated, using a numerical model of an ideal rectangular ice shelf to determine their potential for recording a past ice-stream discharge chronology.

scholarly journals Can Practical Nurses Identify Older Home Care Clients at Risk of Drug-Related Problems–Geriatricians’ Appraisal of Their Risk Screenings: A Pilot Study

2018 ◽  
Vol 34 (3) ◽  
pp. 99-108 ◽  
Author(s):  
Maarit Dimitrow ◽  
Juha Puustinen ◽  
Paula Viikari ◽  
Emmi Puumalainen ◽  
Tero Vahlberg ◽  
...  
Keyword(s):  
At Risk ◽  
Pilot Study ◽  
Home Care ◽  
Clinical Decision Making ◽  
Significant Risk ◽  
Small Sample ◽  
Drug Related Problems ◽  
Medication List ◽  
Predicting Factors ◽  
Risk Patients

Background: Home care (HC) clients are increasingly older, have many chronic diseases, and use multiple medicines and thus are at high risk for drug-related problems (DRPs). Objective: Establish the sensitivity of practical nurse (PN) administered DRP risk assessment tool (DRP-RAT) compared with geriatrician’s assessment of the medical record. Identify the clinically most significant DRPs needing action. Methods: Twenty-six PNs working in HC of Härkätie Health Center in Lieto, Finland, 46 HC clients (≥65 years), and a geriatrician participated in this pilot study. The geriatrician reviewed HC clients’ medications using 3 different methods. The reviews were based on the following: (1) the PN’s risk screening (ie, PN-completed DRP-RAT) and medication list, (2) health center’s medical records, and (3) methods 1 and 2 together. The main outcome was the number of “at-risk patients” (ie, the patient is at risk of clinically significant DRPs) by using each review method. Secondary outcomes were clinically most significant DRP-risk predicting factors identified by the geriatrician. Results: The geriatrician reviewed 45 clients’ medications using all 3 methods. Based on PN-completed DRP-RAT and medication list, 93% (42/45) of the clients were classified as “at-risk patients.” Two other review methods resulted in 45/45 (100%) “at-risk patients.” Symptoms suggestive of adverse drug reactions were the most significant risk predicting factors. Small sample size limits the generalizability of the results. Conclusions: The PN-completed DRP-RAT was able to provide clinically important timely patient information for clinical decision making. DRP-RAT could make it possible to more effectively involve PNs in medication risk management among older HC clients.

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