Multi-hazard warning system tested

Flash flood
The system was used to forecast flash floods in California

An early warning system for earthquakes, tsunamis and floods is being trialled in the US.

Scientists are using GPS technology and other sensors to detect the impending threat of natural disasters.

The network is installed in Southern California and has already helped scientists to alert emergency services to the risk of flash floods.

Yehuda Bock from the Scripps Institute of Oceanography said: “This can help to mitigate threats to public safety.”

And added: “It means real-time information can be made available.”

Ground motion

The minutes and even seconds before a natural disaster strikes are crucial.

Early warning systems can help emergency services to prepare and respond more effectively and can provide vital information for the public.

“Start Quote

We can measure displacements that occur during an earthquake”

Dr Yehuda Bock Scripps Institute of Oceanography

In California, researchers have been testing a prototype network for a range of hazards.

The system builds on existing networks of GPS stations, which use satellite technology to make very precise measurements of any ground movement.

On these, they have installed seismic sensors and other instruments that can track changes in weather conditions.

Dr Bock said: “By combining the data from the GPS with the data from these other sensors, we can measure displacements that occur during an earthquake or another event.”

He added that the system could detect the tremors that appear seconds before a large earthquake strikes, and accurately assess its magnitude and whether it is likely to generate a tsunami.

The GPS sensors and the meteorological instruments also help the team to monitor the water vapour in the air.

Dr Angelyn Moore, from Nasa’s Jet Propulsion Laboratory, said: “It might be surprising that we are using GPS to monitor weather hazards, but GPS is a weather instrument.

“Fundamentally, a GPS station is measuring the time it takes a signal to travel from the GPS satellites to the receiving stations on the ground, and that travel time is modified by the amount of moisture in the air.

“Whenever we measure the position of a GPS station, we are also measuring the amount of water vapour above it.”

Through this, the team is able to track in real time how air moisture is changing and whether heavy rain is likely.

GPS Station
GPS stations like this one are fitted with small seismic and meteorological sensors

In the summer, the researchers used the system to forecast rainfall in San Diego.

Traditionally, some of this data comes from weather balloons.

“But there are only two sites at the southern border of California and these are about 150 miles apart. And the weather balloon launches are also infrequent: in San Diego it’s only every 12 hours,” said Dr Moore.

“In between those many hours between the weather balloon launches, we were able to use the GPS to monitor how the water vapour was changing.”

With this real-time information, the team was able to issue flash flood alerts.

Dr Moore added: “This was verified – there were quite a few reports of flooding.”

The sensing technology is being combined with communication advances to make sure the information is widely distributed, fast.

Dr Mark Jackson, from the National Oceanic and Atmospheric Administration‘s National Weather Service, said: “When a forecaster presses that button to issue that warning, it then goes to the police or fire person that’s responsible for taking action to protect life and property almost instantaneously.

“We also have the public who now on their smartphones can receive warnings directly that say there is a warning in effect for your area.”

The team said the technology was inexpensive, and systems like it could be rolled out around the world.

The findings were presented at the recent American Geophysical Union Fall Meeting in San Francisco.

Training to recognise the early signs of recurrence in schizophrenia.

The lifetime prevalence of schizophrenia is just less than 1% with onset usually occurring during adolescence or early adulthood. People with schizophrenia have an increased risk of suicide and physical illness, as well as impaired occupational and social functioning. A large proportion experience a cyclical pattern of illness, with periods of acute psychotic episodes followed by stable periods of full or partial remission, although these are often accompanied by the presence of residual symptoms.

This Cochrane Review from February 2013 examines whether one particular aspect of psychological treatment for schizophrenia – training in the detection of early signs of relapse – might help people with schizophrenia and those who care for them to work towards a better outcome. The intention was to try to separate the effects of this training from other psychological interventions, but only one of the included studies examined this. All the studies looked at the effects of training provided to people with schizophrenia.

In total, 34 randomised trials were available for the review. These had been reported in 41 publications and included more than 3500 participants. There was a certain symmetry to these studies, with 11 from North America, 11 from Europe and 11 from the East Asia. The remaining study was from Australia. The primary outcomes for the review were relapse and rehospitalisation. The authors conducted analyses of whether or not people experienced one of these events and, where possible, they also looked at the time to the event. Almost all the trials randomised participants individually, but two of the studies used a cluster approach.

Some of the included studies concentrated on early warning signs as the primary intervention, while others had this as part of a wider programme. There were also variations in how the interventions were implemented, what they focused on and who delivered the therapy. For example, the practitioners in some trials were psychologists, while doctors or nurses were involved in other trials. A further complication was that the definition of ‘relapse’ varied across studies, ranging from the onset of symptoms to admission to hospital. Coupled with this considerable heterogeneity, when the authors assessed the quality of the evidence, they judged that it was ‘very low’.

With these cautions in mind, the review found that significantly fewer people relapsed with early warning signs interventions than with usual care (23% versus 43%; risk ratio [RR]: 0.53, 95% confidence interval [CI}: 0.36 to 0.79), based on data from 1502 participants in 15 trials. The risk of re-hospitalisation was also significantly lower with early warning signs interventions compared to usual care (19% versus 39%; RR: 0.48, 95% CI: 0.35 to 0.66), in 15 trials with 1457 participants. Six trials (550 participants) could be included in the analysis of time to relapse, and this was found to be not significantly different between the intervention groups, and there was also no significant difference in time to re-hospitalisation (6 trials, 1149 participants). The findings for participants’ satisfaction with care and economic costs were inconclusive because of a lack of evidence.

The review concludes that early warning signs interventions may have a positive effect on the proportions of people who relapse and who are re-hospitalised, but that the overall quality of the evidence makes it unclear whether the interventions would have similar effects outside trials and suggests that further research is very likely to alter the current estimates. There is also doubt about whether the early warning signs interventions would be effective on their own, given that they were used alongside other psychological interventions in the trials.

The authors note that the interventions might be cost-effective due to reduced hospitalisation and relapse rates, but highlight the importance of further research, of high or moderate quality, before mental health services should routinely provide psychological interventions involving the early recognition and prompt management of early warning signs to adults with schizophrenia. They emphasise the need for future randomised trials to be adequately-powered, designed in ways that will minimise the risk of bias and reported in ways that enhance transparency. They also stress that these studies should evaluate resource costs and resource use, alongside efficacy outcomes and other outcomes that are important to people with serious mental illness and their carers.

Soure: Cochrane Library