A 2-dimensional temporal relational database model for querying errors and updates, and for achieving zero information-loss

A temporal relational database model that supports queries on updates and errors is obtained by attaching 2-dimensional timestamps to data values. The two time dimensions represent real world time, the time when events take place in the real world, and transaction time, the time when such events are recorded in the database. A timestamp in our model is a temporal element, which is a finite union of temporal intervals, or rectangles. The resulting 2-dimensional temporal model includes a robust concept of keys. The concept of keys is essential for restructuring formless temporal information in weak relations;This model does not preclude the possibility that key values may sometimes by recorded in error. Therefore, among its update operations is one that allows changes in key attribute values. Since key values can change to accommodate previous errors, a mechanism to store the true identity of objects is provided. This is done through anchors;Relations in the 2-dimensional model can store the results of all updates. This obviates the need for an explicit update log. Not only that, since updates are now part of the relational structure, constructs of the relational algebra can be used to query their nature. The algebra for the model includes powerful, yet simple, primitives for querying for updates and errors;The zero information-loss model uses the basic 2-dimensional model to provide complete information recoverability. The effect of all database transactions and their circumstances is stored in the model. As a result, there is no longer any need for explicit transaction logs. In the zero information-loss model it is possible to have queries on queries, queries on queries on queries, ad infinitum. This model is a promising framework for building secure and auditable database systems

A formal treatment of updates and errors in a relational database

The concept of an update is external to the classical relational model. When an update is made, the old information is lost at the logical level, and such information may at best be stored in the form of an update log. As a result, the classical relational model is incapable of supporting a query language for updates. We consider two orthogonal concepts of time: the real world time, which captures the changes in the real world, and the transaction time, which is the time when some knowledge of the history of the real world is added to the database. We give a temporal relational model which timestamps the values of attributes with two dimensional timestamps. In this model a formal semantics of updates is given naturally, and the model may be used for querying for the nature of updates and errors. We introduce the concept of a user domain, which is a subset of the universe of time. The user domains support a hierarchy of users, giving each user an appropriate interface. A user domain may be two dimensional, one dimensional, or zero dimensional. The user with the zero dimensional user domain sees the classical snapshot database, and the classical relational algebra as the user interface. Thus, our framework is literally a consistent extension of the classical relational model. One use of our model is that it can be used to impose a logical structure upon the update log: we show that the update log can essentially be recovered from our model, and thus there is no loss of essential information if the update log is discarded. This work is a promising application of temporal databases to mainstream databases

The Concept of Error in a Database: An Application of Temporal Databases

The existing database models do not capture the difference between updates intended to make changes and corrections. The information about errors is external to the database and such information cannot be queried. We give a model to capture the concept of error in a database. The model consisting of 2-dimensional temporal relations is a consistent extension of the classical relational model as well as our l-dimensional temporal relational model. To circumvent the identity of an object from becoming corrupt due to the presence of errors, we make a copy of the correct identity and permanently glue (anchor) it to the object. The transition from the l-dimensional case to the 2-dimensional case is complex, but most of this complexity is absorbed by the system and not passed on to the user. This paper is a promising application of temporal databases to main stream databases

Effects of antiplatelet therapy on stroke risk by brain imaging features of intracerebral haemorrhage and cerebral small vessel diseases: subgroup analyses of the RESTART randomised, open-label trial

Background Findings from the RESTART trial suggest that starting antiplatelet therapy might reduce the risk of recurrent symptomatic intracerebral haemorrhage compared with avoiding antiplatelet therapy. Brain imaging features of intracerebral haemorrhage and cerebral small vessel diseases (such as cerebral microbleeds) are associated with greater risks of recurrent intracerebral haemorrhage. We did subgroup analyses of the RESTART trial to explore whether these brain imaging features modify the effects of antiplatelet therapy

Seropersistence of SII-ChAdOx1 nCoV-19 (COVID-19 vaccine): 6-month follow-up of a randomized,controlled, observer-blind, phase 2/3 immuno-bridging study in Indian adults

AZD1222 (ChAdOx1 nCoV-19) is a replication-deficient adenoviral vectored coronavirus disease-19 (COVID-19) vaccine that is manufactured as SII-ChAdOx1 nCoV-19 by the Serum Institute of India Pvt Ltd following technology transfer from Oxford University/AstraZeneca. The non-inferiority of SII-ChAdOx1 nCoV-19 with AZD1222 was previously demonstrated in an observer-blind, phase 2/3 immuno-bridging study (trial registration: CTRI/2020/08/027170). In this analysis of immunogenicity and safety data 6 months post first vaccination (Day 180), 1,601 participants were randomized 3:1 to SII-ChAdOx1 nCoV-19 or AZD1222 (immunogenicity/reactogenicity cohort n = 401) and 3:1 to SII-ChAdOx1 nCoV-19 or placebo (safety cohort n = 1,200). Immunogenicity was measured by anti-severe acute respiratory syndrome coronavirus 2 spike (anti-S) binding immunoglobulin G and neutralizing antibody (nAb) titers. A decline in anti-S titers was observed in both vaccine groups, albeit with a greater decline in SII-ChAdOx1 nCoV-19 vaccinees (geometric mean titer [GMT] ratio [95% confidence interval (CI) of SII-ChAdOx1 nCoV-19 to AZD1222]: 0.60 [0.41-0.87]). Consistent similar decreases in nAb titers were observed between vaccine groups (GMT ratio [95% CI]: 0.88 [0.44-1.73]). No cases of severe COVID-19 were reported following vaccination, while one case was observed in the placebo group. No causally related serious adverse events were reported through 180 days. No thromboembolic or autoimmune adverse events of special interest were reported. Collectively, these data illustrate that SII-ChAdOx1 nCoV-19 maintained a high level of immunogenicity 6 months post-vaccination. SII-ChAdOx1 nCoV-19 was safe and well tolerated

Venice Chart International Consensus Document on Atrial Fibrillation Ablation: 2011 Update

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/93647/1/j.1540-8167.2012.02381.x.pd

Effects of antiplatelet therapy after stroke due to intracerebral haemorrhage (RESTART): a randomised, open-label trial

Background: Antiplatelet therapy reduces the risk of major vascular events for people with occlusive vascular disease, although it might increase the risk of intracranial haemorrhage. Patients surviving the commonest subtype of intracranial haemorrhage, intracerebral haemorrhage, are at risk of both haemorrhagic and occlusive vascular events, but whether antiplatelet therapy can be used safely is unclear. We aimed to estimate the relative and absolute effects of antiplatelet therapy on recurrent intracerebral haemorrhage and whether this risk might exceed any reduction of occlusive vascular events. Methods: The REstart or STop Antithrombotics Randomised Trial (RESTART) was a prospective, randomised, open-label, blinded endpoint, parallel-group trial at 122 hospitals in the UK. We recruited adults (≥18 years) who were taking antithrombotic (antiplatelet or anticoagulant) therapy for the prevention of occlusive vascular disease when they developed intracerebral haemorrhage, discontinued antithrombotic therapy, and survived for 24 h. Computerised randomisation incorporating minimisation allocated participants (1:1) to start or avoid antiplatelet therapy. We followed participants for the primary outcome (recurrent symptomatic intracerebral haemorrhage) for up to 5 years. We analysed data from all randomised participants using Cox proportional hazards regression, adjusted for minimisation covariates. This trial is registered with ISRCTN (number ISRCTN71907627). Findings: Between May 22, 2013, and May 31, 2018, 537 participants were recruited a median of 76 days (IQR 29–146) after intracerebral haemorrhage onset: 268 were assigned to start and 269 (one withdrew) to avoid antiplatelet therapy. Participants were followed for a median of 2·0 years (IQR [1·0– 3·0]; completeness 99·3%). 12 (4%) of 268 participants allocated to antiplatelet therapy had recurrence of intracerebral haemorrhage compared with 23 (9%) of 268 participants allocated to avoid antiplatelet therapy (adjusted hazard ratio 0·51 [95% CI 0·25–1·03]; p=0·060). 18 (7%) participants allocated to antiplatelet therapy experienced major haemorrhagic events compared with 25 (9%) participants allocated to avoid antiplatelet therapy (0·71 [0·39–1·30]; p=0·27), and 39 [15%] participants allocated to antiplatelet therapy had major occlusive vascular events compared with 38 [14%] allocated to avoid antiplatelet therapy (1·02 [0·65–1·60]; p=0·92). Interpretation: These results exclude all but a very modest increase in the risk of recurrent intracerebral haemorrhage with antiplatelet therapy for patients on antithrombotic therapy for the prevention of occlusive vascular disease when they developed intracerebral haemorrhage. The risk of recurrent intracerebral haemorrhage is probably too small to exceed the established benefits of antiplatelet therapy for secondary prevention

Effects of antiplatelet therapy after stroke due to intracerebral haemorrhage (RESTART): a randomised, open-label trial

Background: Antiplatelet therapy reduces the risk of major vascular events for people with occlusive vascular disease, although it might increase the risk of intracranial haemorrhage. Patients surviving the commonest subtype of intracranial haemorrhage, intracerebral haemorrhage, are at risk of both haemorrhagic and occlusive vascular events, but whether antiplatelet therapy can be used safely is unclear. We aimed to estimate the relative and absolute effects of antiplatelet therapy on recurrent intracerebral haemorrhage and whether this risk might exceed any reduction of occlusive vascular events. Methods: The REstart or STop Antithrombotics Randomised Trial (RESTART) was a prospective, randomised, open-label, blinded endpoint, parallel-group trial at 122 hospitals in the UK. We recruited adults (≥18 years) who were taking antithrombotic (antiplatelet or anticoagulant) therapy for the prevention of occlusive vascular disease when they developed intracerebral haemorrhage, discontinued antithrombotic therapy, and survived for 24 h. Computerised randomisation incorporating minimisation allocated participants (1:1) to start or avoid antiplatelet therapy. We followed participants for the primary outcome (recurrent symptomatic intracerebral haemorrhage) for up to 5 years. We analysed data from all randomised participants using Cox proportional hazards regression, adjusted for minimisation covariates. This trial is registered with ISRCTN (number ISRCTN71907627). Findings: Between May 22, 2013, and May 31, 2018, 537 participants were recruited a median of 76 days (IQR 29–146) after intracerebral haemorrhage onset: 268 were assigned to start and 269 (one withdrew) to avoid antiplatelet therapy. Participants were followed for a median of 2·0 years (IQR [1·0– 3·0]; completeness 99·3%). 12 (4%) of 268 participants allocated to antiplatelet therapy had recurrence of intracerebral haemorrhage compared with 23 (9%) of 268 participants allocated to avoid antiplatelet therapy (adjusted hazard ratio 0·51 [95% CI 0·25–1·03]; p=0·060). 18 (7%) participants allocated to antiplatelet therapy experienced major haemorrhagic events compared with 25 (9%) participants allocated to avoid antiplatelet therapy (0·71 [0·39–1·30]; p=0·27), and 39 [15%] participants allocated to antiplatelet therapy had major occlusive vascular events compared with 38 [14%] allocated to avoid antiplatelet therapy (1·02 [0·65–1·60]; p=0·92). Interpretation: These results exclude all but a very modest increase in the risk of recurrent intracerebral haemorrhage with antiplatelet therapy for patients on antithrombotic therapy for the prevention of occlusive vascular disease when they developed intracerebral haemorrhage. The risk of recurrent intracerebral haemorrhage is probably too small to exceed the established benefits of antiplatelet therapy for secondary prevention