Modelling the role of software in the propagation of failure across National Critical Infrastructures
Previous terrorist attacks, system failures and natural disasters have revealed the problems that many States face in preparing for national civil contingencies. The diversity of critical infrastructures and the interconnections between different systems makes it difficult for planners to ‘think of everything’. For example, the loss of power distribution networks can disrupt rail and road transportation systems. Knock-on effects can also be felt across telecommunications infrastructures as the uninterruptible power supplies (UPS’) that protect mobile phone base stations fail over time. Domestic water supplies are affected when pumping and treatment centres lose power. It is difficult to under-estimate the safety implications of these interdependencies. For example, Pironi, Spinucci and Paganelli describe how the Italian blackout of 2003 affected patients that relied on home parenteral nutrition systems [1]. These individuals used electronic pumps for the overnight infusion of nutritional solutions. The loss of power disrupted their treatment. Different devices responded in different ways as some began to generate alarms while others reverted to battery power. Patients responded in different ways as they became worried about whether or not their systems had sufficient power to complete their treatment for that night. The blackout lasted several days across many areas of Italy. This created further problems as stores of parenteral solution had to be stored in freezers. Other patients were placed at risk when the loss of power began to affect water treatment centres. It became difficult to guarantee that there was no microbiological or toxic contamination in the water supplies for dialysis patients.
Tools for Local Critical Infrastructure Protection : Computational Support for Identifying Safety and Security Interdependencies between Local Critical Infrastructures
Previous terrorist attacks, infrastructure failures and natural disasters have revealed the problems that states face in preparing for civil contingencies. One aspect of this is that the agencies which typically coordinate the protection of critical infrastructures have a national responsibility. However, the impact of particular failures is often focused at a local or regional level. For example, Hurricane Katrina was most acutely felt in the City of New Orleans (over 350,000 people affected), with concentrations in suburban Jefferson Parish (175,000) and St. Bernard Parish (53,000) and along the Mississippi Coast (54,000). The terrorist attacks of 2001 and the UK floods of 2007 also show how multiple localised contingencies can occur at the same time. National infrastructure protection agencies must, therefore, be prepared to provide simultaneous help to multiple local agencies. It is for this reason that national civil protection bodies provide national guidance but then devolve responsibility for the implementation of contingency plans to a local level. Unfortunately, many of the regional groups who are responsible for infrastructure protection have little or no idea about the detailed inter-relationships that exist between their own local infrastructures. For example, in the UK 'risk registers' enumerate local hazards without considering how, for example, an attack on a gas storage facility might damage power distribution infrastructures. Nor do they consider the knock-on effects that such damage might have upon water pumping and purification systems. This paper introduces a geographic information system that is intended to help identify dependencies between local critical infrastructures. Although we focus on supporting interaction between local and national contingency planning within the United Kingdom, similar problems affect many other nations. The goal is to support the 'joined up' thinking that is often recommended in the aftermath of previous failures. (6 pages)
Direct orbital manometry in patients with thyroid-associated orbitopathy.
PURPOSE
To determine orbital tissue tension and orbital compartment compliance in patients with and without thyroid-associated orbitopathy (TAO).


DESIGN
Prospective case series.


PARTICIPANTS
Orbits of patients with TAO (18 orbits) and control patients without TAO (35 orbits) were studied.


METHODS
An orbital manometer was designed to directly measure orbital tissue tension in patients undergoing ocular or orbital surgery.


MAIN OUTCOME MEASURES
Tissue tension was recorded before, during, and for 5 minutes after a 5-ml retrobulbar injection of anesthetic. Orbital compliance was calculated as change in volume divided by change in tissue tension.


RESULTS
Resting orbital tissue tension was 4.4 +/- 2.2 mmHg (mean +/- SD) in normal orbits and 9.7 +/- 4.8 mmHg in orbits of TAO patients (P = 0.0005) Following retrobulbar injection, orbital tissue tension rose to 12.0 +/- 3.6 mmHg (P = 0.0000000000000006 compared with baseline) in the control group and to 36.3 +/- 15.2 mmHg in the TAO group (P = 0.0000007 compared with baseline, and P = 0.000008 TAO group versus control group). Orbital compartment compliance was 0.80 +/- 0.50 ml/mmHg in the control group and 0.27 +/- 0.21 ml/mmHg in the TAO group (P = 0.00001). Resting orbital tissue tension in 8 TAO orbits with compressive optic neuropathy was 12.4 +/- 4.9 mmHg, and was 7.8 +/- 3.5 mmHg in 10 orbits of TAO patients without compressive optic neuropathy (P < 0.05). No adverse events occurred.


CONCLUSIONS
Retrobulbar injection causes consistent measurable changes in orbital tissue tension. Orbital manometry safely demonstrated higher orbital tissue tension and lower orbital compartment compliance in the orbits of TAO patients versus those of normal subjects. Resting orbital tissue tension was higher in the orbits of TAO patients with compressive optic neuropathy than in those orbits without. Compressive optic neuropathy may partially result from an orbital compartment syndrome in some patients with TAO. Directly assessing orbital dynamics in vivo may prove useful as an adjunct in the clinical evaluation of patients with TAO and other orbital disorders.