Dion Corbett, spokesperson for Toyota, Japan's biggest carmaker, said the slump in sales meant that its sales targets for China might be "very difficult to achieve".

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"This makes repeating results very difficult, as researchers might be using different extracts, " Shao says.

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It's very difficult to predict when that might be.

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Further, I find it very difficult to work out what the process might actually be.

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It's the disturbing truth that anyone can turn violent or deadly, and it's proven very difficult to identify who's vulnerable and what the trigger might be.

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"To the extent there is no clarity around what question might be asked or what the outcome of any decision might be, then I think we would see investors being more cautious because it's very difficult for them to accurately price the risk into the investment, " he said.

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Senerath Dissanayake, head of Sri Lanka's archaeology department, said it could prove very difficult to secure the return of such an item to Sri Lanka because legislation might not be adequate to support such a move.

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