Low-molecular-weight heparins in the treatment of venous thromboembolism

Venous thromboembolism is a common disease that is associated with considerable morbidity if left untreated. Recently, low-molecular-weight heparins (LMWHs) have been evaluated for use in acute treatment of deep venous thrombosis and pulmonary embolism. Randomized studies have shown that LMWHs are as effective as unfractionated heparin in the prevention of recurrent venous thromboembolism, and are as safe with respect to the occurrence of major bleeding. A pooled analysis did not show substantial differences among different LMWH compounds used, but no direct comparison of the different LMWHs is currently available. Finally, in patients with pulmonary embolism, there is a relative lack of large studies of daily practice. It could be argued that large prospective studies, in patients who were treated with LMWHs from the moment of diagnosis, are needed

Moving motives:How past and present strategy influence the market

We investigate the market’s reactions to serial acquirers that switch strategy. We collect data on 204 serial acquirers in four high tech industries, and use March’s explore-exploit framework, to classify these firms’ 1,415 acquisitions. We then distinguish, for example, exploration-based acquisitions, conducted after a series of exploitation-based acquisitions. Our results suggest that the market takes a portfolio perspective when reacting to an acquisition. In support of the ambidexterity literature, we show that the market responds positively to a switch from one type of strategy to another. Zooming in on the direction of the shift, we find that the market responds more positively to a switch towards exploration after exploitation, compared with the alternative. In so doing, we contribute to the literature on acquisition motives, by showing that prior announcements matter in explaining market reactions, and we contribute to the literature on ambidexterity, by showing that the market favours firms that oscillate between exploration and exploitation

A benchmark for online non-blocking schema transformations

This paper presents a benchmark for measuring the blocking behavior of schema transformations in relational database systems. As a basis for our benchmark, we have developed criteria for the functionality and performance of schema transformation mechanisms based on the characteristics of state of the art approaches. To address limitations of existing approaches, we assert that schema transformations must be composable while satisfying the ACID guarantees like regular database transactions. Additionally, we have identified important classes of basic and complex relational schema transformations that a schema transformation mechanism should be able to perform. Based on these transformations and our criteria, we have developed a benchmark that extends the standard TPC-C benchmark with schema transformations, which can be used to analyze the blocking behavior of schema transformations in database systems. The goal of the benchmark is not only to evaluate existing solutions for non-blocking schema transformations, but also to challenge the database community to find solutions that allow more complex transactional schema transformations

A meta-analysis of andexanet alfa and prothrombin complex concentrate in the treatment of factor Xa inhibitor-related major bleeding

BACKGROUND: Andexanet alfa (andexanet) and prothrombin complex concentrate (PCC) are both reversal agents for major bleeding in patients using factor Xa inhibitors (FXaIs). Our aim was to evaluate the current evidence for the effectiveness and safety of andexanet and PCC in a systematic review and meta‐analysis. OBJECTIVES: Primary objective was hemostatic effectiveness. Secondary objectives were thromboembolic event rate and mortality. METHODS: A systematic review was performed in PubMed and Embase. Studies describing the effectiveness and/or safety of PCC or andexanet in patients with major bleeding using FXaIs were included. Meta‐analysis was performed using a random‐effects model. RESULTS: Seventeen PCC studies, 3 andexanet studies, and 1 study describing PCC and andexanet were included, comprising 1428 PCC‐treated and 396 andexanet‐treated patients. None of the included studies had control groups, hampering a pooled meta‐analysis to compare the two reversal agents. Separate analyses for andexanet and PCC were performed. In subgroup analysis, the pooled proportion of patients with effective hemostasis in studies that used Annexa‐4 criteria demonstrated a hemostatic effectiveness of 0.85 (95% confidence interval [CI], 0.80‐0.90) in PCC and 0.82 (95% CI, 0.78‐0.87) in andexanet studies. The pooled proportion of patients with thromboembolic events was 0.03 (95% CI, 0.02‐0.04) in PCC and 0.11 (95% CI, 0.04‐0.18) in andexanet studies. CONCLUSION: Based on the available evidence with low certainty from observational studies, PCC and andexanet demonstrated a similar, effective hemostasis in the treatment of major bleeding in patients using FXaIs. Compared to PCC, the thromboembolic event rate appeared higher in andexanet‐treated patients

Towards Online and Transactional Relational Schema Transformations

In this paper, we want to draw the attention of the database community to the problem of online schema changes: changing the schema of a database without blocking concurrent transactions. We have identified important classes of relational schema transformations that we want to perform online, and we have identified general requirements for the mechanisms that execute these transformations. Using these requirements, we have developed an experiment based on the standard TPC-C benchmark to assess the behaviour of existing systems. We look at PostgreSQL, which does not support online schema changes; MySQL, which supports basic online schema changes; and pt-online-schema-change, which is a tool for MySQL that uses triggers to implement online schema changes. We found that none of the existing systems fulfill our requirements. In particular, existing non-blocking solutions can not maintain the ACID guarantees when composing schema transformations. This leads to intermediate states being exposed to database programs, which are non-trivial to handle correctly. As a solution direction, we propose lazy schema transformations, which can naturally be composed into complex schema transformations that properly guarantee the ACID properties, and which have minimal impact on concurrent transactions