A model for a historical database is described which is based upon time-stamped tuples as the unit of storage. The model includes both physical and logical time-stamps. The technical characteristics of write-once laser discs prevent the use of double logical time-stamps. The model distinguishes version from correction-updates. It is shown that if set-valued attributes are involved the use of nu...

The use of computer applications can be a frustrating experience. This study replicates previous studies of the amount of time users – involuntarily – spend trying to diagnose and recover from problems they encounter while using computer applications such as web browsers, email, and text processing. In the present study, 21 users self-reported their frustrating experiences during an average of ...

SUMMARY Neurofibromatosis, an autosomal dominant disorder is characterized by showan cell tumor affecting any Part of the body containing such cell, giving rise to appropriate fealture according to the organ involved but the most characteristic clinical aspect of the disease is pripheral or cranial nerve tumors usually associated with cafe au lait spots more than 6 in number and larger than 1....

A: It came about I was teaching my first year out of college in Portland, Oregon in 1952 in a school that I hated. The district was lower middle class, going downhill fast. There were thirty five kids in the classroom and I decided by mid-year that if I finished the year in one piece, I was not going to go back there. I could not transfer to another school in the system. The main office told me...

Education and learning have witnessed some important changes in the past few years. The appearance and success of the information society may well be one of the main factors for such change. Indeed. children are increasingly more and more at ease with the use of computers and technology. So, eapitalising on this advantage, our research aims at exploring and enriching current and new classroom a...

We present coding methods for protecting against tampering of write-once optical disks, which turns them into a secure digital medium for applications where critical information must be stored in a way that prevents or allows detection of an attempt at falsification. Our method involves adding a small amount of redundancy to a modulated sector of data. This extra redundancy is not used for norm...

The generalized write-once memory introduced by Fiat and Shamir is a q-ary information storage medium. Each storage cell is expected to store one of q symbols, and the legal state transitions are described by an arbitrary directed acyclic graph. This memory model can be understood as a generalization of the binary write-once memory which was introduced by Rivest and Shamir. During the process o...

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CONTEXT The effect of fish consumption or long-chain omega-3 polyunsaturated fatty acid (PUFA) intake on risk of stroke remains uncertain. OBJECTIVE To examine the relation of fish consumption and long-chain omega-3 PUFA intake and risk of stroke in men. DESIGN AND SETTING The Health Professional Follow-up Study, a US prospective cohort study with 12 years of follow-up. PARTICIPANTS A tot...

diffuse hepatic inltration is an unusual form of hodgkin's disease (hd). its manifestation as progressive hepatitis or with hepatic failure is even rarer and can be difcult to diagnose. we aim to describe an unusual case of liver failure due to hd. a middle-aged woman with a 10 month history of daily febrile episodes, constitutional symptoms and strikingly high levels of serum ferritin was admi...