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The Argentine submarine ARA (Armada de la República Argentina) San Juan went missing on November 15th, 2017, with its last confirmed contact location around 600 kilometres East of Comodoro Rivadavia, Chubut, Argentina. In the days following the initiation of the multi-national search and rescue mission, the Comprehensive Nuclear-Test-Ban Treaty Organization (CTBTO) analysed data recorded by its International Monitoring System (IMS) sensor network for any signals that could support this effort. Two of the IMS hydrophone stations, HA10 in the central Atlantic Ocean and HA04 in the southern Indian Ocean, were found to have recorded an unusual hydroacoustic signal of unknown nature (a “hydroacoustic anomaly”), which originated from the vicinity of the last known location of the ARA San Juan. On December 1st, 2017, confirmation of the detection and localization capability of the IMS network was made possible by a calibration test involving a depth charge deployed by the Argentine Navy. Also this signal was detected by the two IMS hydrophone stations and its origin located to within 39 km of the announced deployment location. After extended search operations, on November 17th, 2018, the ARA San Juan was found on the seabed at approximately 900 metres depth less than 20 km from the location of the hydroacoustic anomaly provided by CTBTO. This paper presents the methodologies applied by CTBTO within months after the loss of the submarine, aimed at detecting, locating and characterizing the November 15th signal of unknown origin and the December 1st calibration explosion.

OBJECTIVEPapers from 2002 to 2017 have highlighted consistent unique socioeconomic challenges and opportunities facing military neurosurgeons. Here, the authors focus on the reserve military neurosurgeon who carries the dual mission of both civilian and military responsibilities.METHODSSurvey solicitation of current active duty and reserve military neurosurgeons was performed in conjunction with the AANS/CNS Joint Committee of Military Neurosurgeons and the Council of State Neurosurgical Societies. Demographic, qualitative, and quantitative data points were compared between reserve and active duty military neurosurgeons. Civilian neurosurgical provider data were taken from the 2016 NERVES (Neurosurgery Executives Resource Value and Education Society) Socio-Economic Survey. Economic modeling was done to forecast the impact of deployment or mobilization on the reserve neurosurgeon, neurosurgery practice, and the community.RESULTSSeventy-five percent (12/16) of current reserve neurosurgeons reported that they are satisfied with their military service. Reserve neurosurgeons make significant contributions to the military’s neurosurgical capabilities, with 75% (12/16) having been deployed during their career. No statistically significant demographic differences were found between those serving on active duty and those in the reserve service. However, those who served in the reserves were more likely to desire opportunities for improvement in the military workflow requirements compared with their active duty counterparts (p = 0.04); 92.9% (13/14) of current reserve neurosurgeons desired more flexible military drill programs specific to the needs of practicing physicians. The risk of reserve deployment is also borne by the practices, hospitals, and communities in which the neurosurgeon serves in civilian practice. This can result in fewer new patient encounters, decreased collections, decreased work relative value unit generation, increased operating costs per neurosurgeon, and intangible limitations on practice development. However, through modeling, the authors have illustrated that reserve physicians joining a larger group practice can significantly mitigate this risk. What remains astonishing is that 91.7% of those reserve neurosurgeons who were deployed noted the experience to be rewarding despite seeing a 20% reduction in income, on average, during the fiscal year of a 6-month deployment.CONCLUSIONSReserve neurosurgeons are satisfied with their military service while making substantial contributions to the military’s neurosurgical capabilities, with the overwhelming majority of current military reservists having been deployed or mobilized during their reserve commitments. Through the authors’ modeling, the impact of deployment on the military neurosurgeon, neurosurgeon’s practice, and the local community can be significantly mitigated by a larger practice environment.

From the outset, I would like to express my appreciation to the organizers for the invitation to this Conference. The theme of this session “Role of science in technical and international cooperation” is very topical as most of you would agree that we are living in particularly challenging times with serious tensions among international actors which can be compounded by mistrust and misunderstanding.

This paper provides information regarding the use of the Xilinx Virtex-4 field-programmable gate array (FPGA) in a spacecraft deployed to low-earth orbit. The results are compared to pre-deployment accelerated single-event effects (SEEs) and fault-injection testing.

The CTBT International Monitoring System (IMS) is a world-wide network of seismic, infrasound, hydroacoustic, and radionuclide stations designed and deployed to detect nuclear explosions. Two of the IMS hydrophone stations, one in the Atlantic Ocean and one in the southern Indian Ocean, recorded signals of unknown nature which originated from the vicinity of the last known location of the San Juan submarine on 15 November 2017. To verify the accuracy of this hydroacoustic event localization, the Argentinian Navy successively deployed a controlled depth charge to the North of the last known position of the submarine. The signals from this source were also detected on the same two IMS hydrophone stations. Several techniques were employed to compare hydroacoustic features in the signals from the 15 November event and the controlled depth charge, including an assessment of spectral energy levels, cepstral analysis, azimuth and arrival time estimation of direct and reflected signals. This presentation compares the received signals, examines their main characteristics, and, through the use of acoustic modelling, identifies possible propagation paths between the source and receiver, including a plausible explanation of early arrivals hypothesized to follow propagation paths through the Antarctic ice sheet.

Cerebral vasospasm (VSP) is a frequent complication after aneurysmal and traumatic subarachnoid hemorrhage (SAH) and carries significant morbidity and mortality. Traumatic brain injury (TBI) is associated with the severest casualties from Operation Iraqi Freedom and Operation Enduring Freedom. From Oct. 1, 2008 the US Army Medical Department initiated a transcranial Doppler (TCD) ultrasound service for TBI; included patients were retrospectively evaluated for TCD-determined incidence of posttraumatic cerebral vasospasm and intracranial hypertension after wartime TBI. Patients were identified using a computerized registry and a prospective TCD database maintained in the Sentient NeuroCare Services. TCD recordings of mean cerebral blood flow velocities (CBFV) and Pulsatility Indices of the anterior and posterior circulation vessels were recorded using a 2-MHz transducer (Doppler Box, DWL/Compumedics, USA, Germany/Australia). Comprehensive TCD protocol was applied in all cases: if mean CBFV equaled or exceeded 100 cm/sec., 140 cm.sec and 200 cm/sec the TCD signs of mild vasospasm, moderate vasospasm and severe vasospasm respectively were considered present. 122 patients were investigated with daily TCD studies and comprehensive TCD protocol and published diagnostic criteria for VSP and raised intracranial pressure (ICP) were applied. TCD signs of mild, moderate and severe VSP involving anterior circulation vessels were observed in 71%, 42% and 16% of patients, respectively. TCD signs of mild, moderate and severe VSP involving posterior circulation vessels were observed in 57%, 32% and 14% of patients, respectively. TCD signs of intracranial hypertension were recorded in 43%, eight patients (7%) underwent transluminal angioplasty for post-traumatic symptomatic vasospasm treatment. These findings demonstrate that cerebral arterial VSP and intracranial hypertension are frequent and significant complications of combat TBI, therefore daily TCD monitoring is recommended for their recognition and subsequent management. Acknowledgements. The opinions and views expressed herein belong solely to those of the authors. They are not nor should they be implied as being endorsed by the Uniformed Services University of the Health Sciences, Department of the Army, Department of the Navy, Department of Defense or any other branch of the Federal government of the United States. This paper supported in part, by the US Army Medical Research and Material Command’s Telemedicine and Advanced Technology Research Center (Fort Detrick, MD, USA).

This paper provides information regarding the use of the Xilinx Virtex-4 field-programmable gate array in a spacecraft deployed to low-earth orbit. The results are compared to pre-deployment accelerated and fault-injection testing.

Medical and industrial fadioisotopes are fundamental tools used in science, medicine and industry with an ever expanding usage in medical practice where their availability is vital. Very sensitive environmental radionuclide monitoring networks have been developed for nuclear-security-related monitoring [particularly Comprehensive Test-Ban-Treaty (CTBT) compliance verification] and are now operational.

The Multispectral Thermal Imager, MTI, is a research and development project sponsored by the United States Department of Energy. The primary mission is to demonstrate advanced multispectral and thermal imaging from a satellite, including new technologies, data processing and analysis techniques. The MTI builds on the efforts of a number of earlier efforts, including Landsat, NASA remote sensing missions, and others, but the MTI incorporates a unique combination of attributes. The MTI satellite was launched on 12 March 2000 into a 580 km x 610 km, sun-synchronous orbit with nominal 1 am and 1 pm equatorial crossing times. The Air Force Space Test Program provided the Orbital Sciences Taurus launch vehicle. The satellite has a design lifetime of a year, with the goal of three years. The satellite and payload can typically observe six sites per day, with either one or two observations per site from nadir and off-nadir angles. Data are stored in the satellite memory and down-linked to a ground station at Sandia National Laboratory. Data are then forwarded to the Data Processing and Analysis Center at Los Alamos National Laboratory for processing, analysis and distribution to the MTI team and collaborators. We will provide an overview of the Project, a few examples of data products, and an introduction to more detailed presentations in this special session.© (2001) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.