Adaptive-Aggressive Traders Don't Dominate

For more than a decade Vytelingum's Adaptive-Aggressive (AA) algorithm has been recognized as the best-performing automated auction-market trading-agent strategy currently known in the AI/Agents literature; in this paper, we demonstrate that it is in fact routinely outperformed by another algorithm when exhaustively tested across a sufficiently wide range of market scenarios. The novel step taken here is to use large-scale compute facilities to brute-force exhaustively evaluate AA in a variety of market environments based on those used for testing it in the original publications. Our results show that even in these simple environments AA is consistently out-performed by IBM's GDX algorithm, first published in 2002. We summarize here results from more than one million market simulation experiments, orders of magnitude more testing than was reported in the original publications that first introduced AA. A 2019 ICAART paper by Cliff claimed that AA's failings were revealed by testing it in more realistic experiments, with conditions closer to those found in real financial markets, but here we demonstrate that even in the simple experiment conditions that were used in the original AA papers, exhaustive testing shows AA to be outperformed by GDX. We close this paper with a discussion of the methodological implications of our work: any results from previous papers where any one trading algorithm is claimed to be superior to others on the basis of only a few thousand trials are probably best treated with some suspicion now. The rise of cloud computing means that the compute-power necessary to subject trading algorithms to millions of trials over a wide range of conditions is readily available at reasonable cost: we should make use of this; exhaustive testing such as is shown here should be the norm in future evaluations and comparisons of new trading algorithms.Comment: To be published as a chapter in "Agents and Artificial Intelligence" edited by Jaap van den Herik, Ana Paula Rocha, and Luc Steels; forthcoming 2019/2020. 24 Pages, 1 Figure, 7 Table

Tamoxifen for prevention of breast cancer: extended long-term follow-up of the IBIS-I breast cancer prevention trial

© Cuzick et al. Open Access article distributed under the terms of CC BY.http://dx.doi.org/10.1016/S1470-2045(14)71171-

Staging the axilla in breast cancer: An audit of lymph-node retrieval in one U.K. regional centre

Aims: Many surgeons undertake a level 1 axillary dissection in patients with invasive breast cancer. This dissection yields a variable number of lymph nodes for histological study. In this study, we report the consequences of this policy for staging of the axilla. Methods: Between January 1995 and December 1995, 236 patients with a diagnosis of invasive breast cancer underwent axillary surgery. Results: A median of eight nodes was identified (range 0-30). In only 11 patients less than four nodes were identified. An increase in the number of nodes harvested was associated with a higher proportion of node-positive patients and a higher number of metastatic nodes identified. Conclusions: We concluded that a standardized approach to axillary dissection consistently yields an adequate sample of lymph nodes for staging purposes. Most importantly, larger node samples yield higher detection rates for metastasis. This has a significant bearing on patient selection for adjuvant chemotherapy when compared with more limited sampling practices, including solitary sentinel node detection and biopsy.</p

Acute kidney injury in hematopoietic stem cell transplantation

© 2019 Wolters Kluwer Health, Inc. Purpose of review Acute kidney injury (AKI) in the setting of hematopoietic stem cell transplantation (HSCT) is common in pediatric and adult patients. The incidence ranges from 12 to 66%, and development of AKI in the posttransplant course is independently associated with higher mortality. Recent findings Patients who undergo HSCT have many risk factors for developing AKI, including sepsis, use of nephrotoxic medications, graft versus host disease (GVHD), and veno-occlusive disease (VOD). In addition, engraftment syndrome/cytokine storm, transplant-associated thrombotic microangiopathy (TA-TMA), and less common infections with specific renal manifestations, such as BK and adenovirus nephritis, may lead to kidney injury. There has been significant advancement in the understanding of TA-TMA in particular, especially the role of the complement system in its pathophysiology. The role of early dialysis has been explored in the pediatric population, but not well studied in adult HSCT recipients Summary This review provides an update on the risk factors, causes, and treatment approaches to HSCT-associated AKI. Video abstract http://links.lww.com/COCC/A29