Preservation datastores: Architecture for preservation aware storage

The volumes of digital infonnation are growing continuously and most of today's information is "born digital". Alongside this trend, business, scientific, artistic and cultural needs require much of this information to be kept for decades, centuries or longer. The convergence of these two trends implies the need for storage systems that support very long tenn preservation for digital information. We describe Preservation DataStores, a novel storage architecture to support digital preservation. It is a layered architecture that builds upon open standards, along with the OAlS, XAM and OSD standards. This new architecture transfonns the logical information-object, a basic concept in preservation systems, into a physical storage object. The transformation allows more robust and optimized implementations for preservation aware storage. The architecture of Preservation DataStores is being developed as all infrastructure component of the CASPAR project ' and will be tested in the context of this project using scientific, cultural, and artistic data. 'Work partially supported by European Community under the Information Society Technologies (1ST) program of the 6th FP for RTD- project CASPAR contract IST-033572. The authors are solely responsible for the content of this paper. It does not represent the opinion of the European Community, and the European Community is not responsible for any use that might be made of data appearing therein. 1

The impact of adjunctive adenosine infusion during exercise myocardial perfusion imaging: results of the Both Exercise and Adenosine Stress Test (BEAST) trial

Failure to achieve an adequate heart rate limits the sensitivity of exercise myocardial perfusion imaging (MPI) for the detection of coronary artery disease. In addition, it is often not possible to discontinue medications that may blunt the heart rate response to exercise, because of conditions such as hypertension or angina. However, if pharmacologic stress testing is performed, the ability to assess functional capacity is lost. Accordingly, we developed a protocol that incorporates adenosine stress with symptom-limited exercise. As part of a multicenter study, 35 patients were enrolled prospectively and underwent both exercise MPI and exercise MPI with a 4-minute adenosine infusion on a separate day. Technetium 99m sestamibi was injected at or near peak exercise (exercise only) and at 2 minutes into the adenosine infusion (combined exercise and adenosine). The perfusion images were interpreted in a blinded fashion. The combined adenosine and exercise protocol was well tolerated. The summed stress scores and summed difference scores were greater in the exercise-plus-adenosine group than in the exercise-only group (10.0 vs 8.5, P = .02, and 4.9 vs 3.3, P = .002, respectively). Exercise time was slightly but significantly less with the exercise-plus-adenosine protocol (8 minutes 46 seconds vs 8 minutes 11 seconds, P = .027). A protocol combining 4 minutes of adenosine infusion with symptom-limited exercise was safe and well tolerated. Furthermore, this protocol resulted in a greater amount of myocardial ischemia detected on MPI while allowing for the assessment of functional capacity. A combined exercise and adenosine protocol may be a useful test for patients undergoing MPI who are unlikely to achieve an adequate chronotropic response

Mutations in the Cilia Gene ARL13B Lead to the Classical Form of Joubert Syndrome

Joubert syndrome (JS) and related disorders are a group of autosomal-recessive conditions sharing the “molar tooth sign” on axial brain MRI, together with cerebellar vermis hypoplasia, ataxia, and psychomotor delay. JS is suggested to be a disorder of cilia function and is part of a spectrum of disorders involving retinal, renal, digital, oral, hepatic, and cerebral organs. We identified mutations in ARL13B in two families with the classical form of JS. ARL13B belongs to the Ras GTPase family, and in other species is required for ciliogenesis, body axis formation, and renal function. The encoded Arl13b protein was expressed in developing murine cerebellum and localized to the cilia in primary neurons. Overexpression of human wild-type but not patient mutant ARL13B rescued the Arl13b scorpion zebrafish mutant. Thus, ARL13B has an evolutionarily conserved role mediating cilia function in multiple organs