Predicting acoustic dose associated with marine mammal behavioural responses to sound as detected with fixed acoustic recorders and satellite tags.

To understand the consequences of underwater noise exposure for cetaceans, there is a need for assessments of behavioural responses over increased spatial and temporal scales. Bottom-moored acoustic recorders and satellite tags provide such long-term and large spatial coverage of behaviour compared to short-duration acoustic-recording tags. However, these tools result in a decreased resolution of data from which an animal response can be inferred, and no direct recording of the sound received at the animal. This study discusses the consequence of the decreased resolution of data from satellite tags and fixed acoustic recorders on the acoustic dose estimated by propagation modelling and presents a method for estimating the range of sound levels that animals observed with these methods have received. This problem is illustrated using experimental results obtained during controlled exposures of northern bottlenose whales (Hyperoodon ampullatus) exposed to naval sonar, carried out near Jan Mayen, Norway. It is shown that variability and uncertainties in the sound field, resulting from limited sampling of the acoustic environment, as well as decreased resolution in animal locations, can lead to quantifiable uncertainties in the estimated acoustic dose associated with the behavioural response (in this case avoidance and cessation of foraging).

Detecting suspicious activities at sea based on anomalies in Automatic Identification Systems transmissions.

Automatic Identification Systems (AIS) are a standard feature of ocean-going vessels, designed to allow vessels to notify each other of their position and route, to reduce collisions. Increasingly, the system is being used to monitor vessels remotely, particularly with the advent of satellite receivers. One fundamental problem with AIS transmission is the issue of gaps in transmissions. Gaps occur for three basic reasons: 1) saturation of the system in locations with high vessel density; 2) poor quality transmissions due to equipment on the vessel or receiver; and 3) intentional disabling of AIS transmitters. Resolving which of these mechanisms is responsible for generating gaps in transmissions from a given vessel is a critical task in using AIS to remotely monitor vessels. Moreover, separating saturation and equipment issues from intentional disabling is a key issue, as intentional disabling is a useful risk factor in predicting illicit behaviors such as illegal fishing. We describe a spatial statistical model developed to identify gaps in AIS transmission, which allows calculation of the probability that a given gap is due to intentional disabling. The model we developed successfully identifies high risk gaps in the test case example in the Arafura Sea. Simulations support that the model is sensitive to frequent gaps as short as one hour. Results in this case study area indicate expected high risk vessels were ranked highly for risk of intentional disabling of AIS transmitters. We discuss our findings in the context of improving enforcement opportunities to reduce illicit activities at sea.

Meteorological variability and infectious disease in Central Africa: a review of meteorological data quality.

Central African countries may bear high climate change-related infectious disease burdens because of preexisting high rates of disease, poor healthcare infrastructure, land use changes, and high environmental change vulnerabilities. However, making connections between climate and infectious diseases in this region is hampered by the paucity of high-quality meteorological data. This review analyzes the sources and quality of meteorological data used to study the interactions between weather and infectious diseases in Central African countries. Results show that 23% of studies used meteorological data that mismatched with the disease spatial scale of interest. Use of inappropriate weather data was most frequently identified in analyses using meteorological station data or gridded data products. These findings have implications for the interpretation of existing analyses and provide guidance for the use of climate data in future analyses of the connections between meteorology and infectious diseases in Central Africa.

Validity and feasibility of a satellite imagery-based method for rapid estimation of displaced populations.

BACKGROUND: Estimating the size of forcibly displaced populations is key to documenting their plight and allocating sufficient resources to their assistance, but is often not done, particularly during the acute phase of displacement, due to methodological challenges and inaccessibility. In this study, we explored the potential use of very high resolution satellite imagery to remotely estimate forcibly displaced populations. METHODS: Our method consisted of multiplying (i) manual counts of assumed residential structures on a satellite image and (ii) estimates of the mean number of people per structure (structure occupancy) obtained from publicly available reports. We computed population estimates for 11 sites in Bangladesh, Chad, Democratic Republic of Congo, Ethiopia, Haiti, Kenya and Mozambique (six refugee camps, three internally displaced persons' camps and two urban neighbourhoods with a mixture of residents and displaced) ranging in population from 1,969 to 90,547, and compared these to "gold standard" reference population figures from census or other robust methods. RESULTS: Structure counts by independent analysts were reasonably consistent. Between one and 11 occupancy reports were available per site and most of these reported people per household rather than per structure. The imagery-based method had a precision relative to reference population figures of <10% in four sites and 10-30% in three sites, but severely over-estimated the population in an Ethiopian camp with implausible occupancy data and two post-earthquake Haiti sites featuring dense and complex residential layout. For each site, estimates were produced in 2-5 working person-days. CONCLUSIONS: In settings with clearly distinguishable individual structures, the remote, imagery-based method had reasonable accuracy for the purposes of rapid estimation, was simple and quick to implement, and would likely perform better in more current application. However, it may have insurmountable limitations in settings featuring connected buildings or shelters, a complex pattern of roofs and multi-level buildings. Based on these results, we discuss possible ways forward for the method's development.

Dramatic effect of pop-up satellite tags on eel swimming.

The journey of the European eel to the spawning area in the Sargasso Sea is still a mystery. Several trials have been carried out to follow migrating eels with pop-up satellite tags (PSATs), without much success. As eels are very efficient swimmers, tags likely interfere with their high swimming efficiency. Here we report a more than twofold increase in swimming cost caused by a regular small satellite tag. The impact was determined at a range of swimming speeds with and without tag in a 2-m swimming tunnel. These results help to explain why the previous use of PSATs to identify spawning sites in the Sargasso Sea was thus far unsuccessful.

Summit-to-sea mapping and change detection using satellite imagery: tools for conservation and management of coral reefs

Continuous summit-to-sea maps showing both land features and shallow-water coral reefs have been completed in Puerto Rico and the U.S. Virgin Islands, using circa 2000 Landsat 7 Enhanced Thematic Mapper (ETM+) Imagery. Continuous land/sea terrain was mapped by merging Digital Elevation Models (DEM) with satellite-derived bathymetry. Benthic habitat characterizations were created by unsupervised classifications of Landsat imagery clustered using field data, and produced maps with an estimated overall accuracy of>75% (Tau coefficient >0.65). These were merged with Geocover-LC (land use/land cover) data to create continuous land/ sea cover maps. Image pairs from different dates were analyzed using Principle Components Analysis (PCA) in order to detect areas of change in the marine environment over two different time intervals: 2000 to 2001, and 1991 to 2003. This activity demonstrates the capabilities of Landsat imagery to produce continuous summit-to-sea maps, as well as detect certain changes in the shallow-water marine environment, providing a valuable tool for efficient coastal zone monitoring and effective management and conservation

Summit-to-sea mapping and change detection using satellite imagery: tools for conservation and management of coral reefs.

Continuous summit-to-sea maps showing both land features and shallow-water coral reefs have been completed in Puerto Rico and the U.S. Virgin Islands, using circa 2000 Landsat 7 Enhanced Thematic Mapper (ETM+) Imagery. Continuous land/sea terrain was mapped by merging Digital Elevation Models (DEM) with satellite-derived bathymetry. Benthic habitat characterizations were created by unsupervised classifications of Landsat imagery clustered using field data, and produced maps with an estimated overall accuracy of>75% (Tau coefficient >0.65). These were merged with Geocover-LC (land use/land cover) data to create continuous land/ sea cover maps. Image pairs from different dates were analyzed using Principle Components Analysis (PCA) in order to detect areas of change in the marine environment over two different time intervals: 2000 to 2001, and 1991 to 2003. This activity demonstrates the capabilities of Landsat imagery to produce continuous summit-to-sea maps, as well as detect certain changes in the shallow-water marine environment, providing a valuable tool for efficient coastal zone monitoring and effective management and conservation.

[Spacial modeling of cutaneous leishmaniasis risk zones]. / Modelagem espacial de zonas de risco da leishmaniose tegumentar americana.

OBJECTIVE: To spatially delimit cutaneous leishmaniasis (CL) human contact risk zones (CoRZ) using remote sensing and geoprocessing techniques. METHODS: A total of 27 CL cases reported from 1992 to 1997 in the municipality Itapira, Brazil, were studied. The influence of some important environmental variables related to CL such as altitude and vegetation density measured by normalized difference vegetation index (NDVI) images were analyzed for each CoRZ. RESULTS: The results showed that about 50% of the dwellings where CL cases were reported were located less than 200 meters from the limits of forest remnant area; more than 70% of the total area of the CoRZ, for each criterion, were in altitudes lower than 750 meters; and about 50% of the CoRZ, for each criterion, were located in a very dense green area (NDVI ranging from 0.45 to 1.00). CONCLUSIONS: The study shows there may be three transmission modes in the study area: intra-forest, extra-forest (in this setting, transmission might be influenced by the vegetation density surrounding forest remnants); or domiciliary.

The Interplanetary Internet: a communications infrastructure for Mars exploration.

A strategy is being developed whereby the current set of internationally standardized space data communications protocols can be incrementally evolved so that a first version of an operational "Interplanetary Internet" is feasible by the end of the decade. This paper describes its architectural concepts, discusses the current set of standard space data communications capabilities that exist to support Mars exploration and reviews proposed new developments. We also speculate that these current capabilities can grow to support future scenarios where human intelligence is widely distributed across the Solar System and day-to-day communications dialog between planets is routine.

Simulações da SAR na cabeça e antenas planares para telefones móveis / SAR simulations and planar antennas for mobile phones

A Taxa de Absorção Específica (SAR) na cabeça dos usuários de telefones móveis é simulada utilizando o método das Diferenças Finitas no Domínio do Tempo (FDTD) quando antenas tipo monopolo convencionais e quando antenas diretivas planares são utilizadas. São também resumidos o projeto de antenas tipo patch retangular em microstrip, suas características de desempenho esperadas e medidas são apresentadas. São calculados entre outros, a taxa de onda estacionária e a largura de banda simuladas no software Ensemble®, o diagrama de irradiação no plano horizontal e o campo na região próxima, claculado em simulação em três dimensões - 3D com algoritmo baseado em FDTD. Medidas da taxa de Onda Estacionária VSWR e dos diagramas de irradiação horizontal são mostradas. Verifica-se uma excelente correlação entre os resultados das medidas e os obtidos com o método FDTD em simulações com plano de terra finito e sem aterramento efetivo. Observa-se que este tipo de antena pode ser utilizado em uma nova geração de telefones móveis, constituindo-se em uma alternativa conveniente para melhorar o desempenho destes transcetores, diminuindo também os riscos à saúde dos usuários

Wireless and satellite transmission of prehospital focused abdominal sonography for trauma.

OBJECTIVE: As military operations become smaller and more remote and as humanitarian missions increase, ultrasound technology is emerging as a valuable asset for defining injuries in austere settings. This study evaluated the feasibility of focused abdominal sonography for trauma (FAST) examinations in a field environment with real-time images sent wireless to an antenna and over satellite. METHODS: Using a 6-lb SonoSite portable ultrasound device with battery pack, FAST examinations were performed on a healthy volunteer, transferred wireless at distances of 1,000 and 1,500 feet from the receiving antenna using a vest-mounted microwave transmitter, and then redirected over satellite (INMARSAT) to a remote hospital for review by emergency physicians, and a radiologist. RESULTS: Real-time wireless transmissions at 1,500 feet reliably yielded images without quality or interpretability drop compared with those recorded digitally at the examination site. A 32% reduction in image quality and interpretability was seen with still images and a 42% reduction was noted with cine loops using INMARSAT. The authors did not find the upper distance limit of the wireless transmitter used. CONCLUSION: This study suggests 1) that remote FAST examinations are plausible for prehospital care and triage using new-generation portable ultrasound units, 2) that line-of-sight transmission of FAST examinations when compared with on-site images results in no degradation in image quality or interpretability at distances used, 3) that ranges greater than 1,500 feet are feasible for interpretable examinations and therefore line-of-site mass casualty or field triage sites, and 4) that real-time INMARSAT transmission of FAST examinations at 64 kbps may serve a limited role for remote clinical interpretation.

Continuous time transfer using GPS carrier phase.

The Astronomical Institute of the University of Berne is hosting one of the Analysis Centers (AC) of the International GPS Service (IGS). A network of a few GPS stations in Europe and North America is routinely analyzed for time transfer purposes, using the carrier phase observations. This work is done in the framework of a joint project with the Swiss Federal Office of Metrology and Accreditation (METAS). The daily solutions are computed independently. The resulting time transfer series show jumps of up to 1 ns at the day boundaries. A method to concatenate the daily time transfer solutions to a continuous series was developed. A continuous time series is available for a time span of more than 4 mo. The results were compared with the time transfer results from other techniques such as two-way satellite time and frequency transfer. This concatenation improves the results obtained in a daily computing scheme because a continuous time series better reflects the characteristics of continuously working clocks.

Effect of wavelet compression on data transmission in a multipurpose wireless telemedicine system.

We have developed a novel emergency telemedicine system which allows the transmission of physiological data (electrocardiogram, oximetry, blood pressure and temperature) and still images of the patient. The transmission is performed through wireless links using either GSM mobile phones or satellite. Because of the low bandwidth available through these links, data compression is required to allow realtime transmission of electrocardiographic (ECG) data. A new integrated design approach for an optimal zonal wavelet compression (OZWC) method was implemented for the ECG data. The performance of the mobile system with compressed ECG data segments was evaluated in terms of the percentage root-mean-square difference and visual inspection. The optimum wavelet algorithm achieved a maximum compression ratio of 18:1 with low distortion.

Training for surgeons using digital satellite television and videoconferencing.

The TETRASUR project (TELematics TRAining for SURgeons) has investigated the effectiveness of distance-learning technologies in the delivery of training for doctors who are studying for membership of the Royal College of Surgeons. Digital satellite television receivers and ISDN videoconferencing equipment have been installed in hospitals to deliver the course modules, including a series of live television programmes transmitted by satellite. ISDN videoconferencing was integrated, live, into the satellite broadcasts to bring in guest lecturers and for interactive discussions with the trainee doctors. Videoconferencing was also used for seminars and discussion groups. These methods proved to be effective and popular with the doctors, although there was some dissatisfaction with the visual quality of the ISDN videoconferencing at 128 kbit/s. Efforts are now being made to improve the quality of the video feed from remote sites using ISDN at 384 kbit/s.

The AIDMAN project--a telemedicine approach to cardiology investigation, referral and outpatient care.

The AIDMAN pilot project will connect health clinics on remote Greek islands with a mainland hospital. We have developed a virtual consultation workstation for the project, together with a satellite communication network. A UK pilot site has been used to test the concepts and applications between a surgery in Chorleywood and St Mary's Hospital in London.

Medical communication from emergency scenes using a notepad computer.

We have developed a communication system in which data are transferred from the scene of an emergency in the form of an electronic record on a notepad computer by means of a satellite link (MODACOM). The data are received at the dispatch centre and transferred to the admitting hospital automatically. In a prospective study of 53 emergencies the technical suitability of the system was investigated. First-sight information could be fed into the computer in 15 s and transmitted within 3 min of arrival on the scene. For 16 patients with life-threatening conditions, the admitting hospital was notified on average after 13.6 min (SD 6.0), whereas by conventional VHF radio it took 35.5 min (SD 8.9). In addition, more precise information about the patient's condition was received at the hospital.

Global positioning system. New directions in ground/air communications.

The use of helicopters for on-scene emergency response has become an important part of the EMS system. In fact, air transport of advanced-level personnel to the scene of accidents and the rapid transport of patients to acute-care facilities frequently have been lifesaving.