Unrelated donor bone marrow transplantation for chronic myelogenous leukemia: a decision analysis

BACKGROUND: Chronic myelogenous leukemia (CML) is an indolent but ultimately fatal disease. Because the natural history of CML varies and quality of life with CML may be excellent until shortly before death, deciding whether and when to pursue unrelated donor bone marrow transplantation is often difficult. OBJECTIVE: To compare early transplantation, delayed transplantation, and no transplantation for patients with chronic-phase CML on the basis of discounted, quality-adjusted life expectancy. DESIGN: A markov model comparing different strategies was constructed. This model considers patient age, quality of life, risk aversion, and the competing risks for CML progression and transplant toxicity. SETTING: Therapeutic decision at the time of diagnosis of CML. PATIENTS: The base case is a 35-year-old patient with intermediate-prognosis CML. Younger and older patients with better and worse prognoses are also evaluated. INTERVENTION: Early transplantation, delayed transplantation, and no transplantation. MEASUREMENTS: Quality-adjusted, discounted life expectancy. RESULTS: For patients with newly diagnosed CML, transplantation within the first year provides the greatest quality-adjusted expected survival, although this benefit decreases with increasing patient age. For a 35-year-old patient with intermediate-prognosis CML, transplantation within the first year results in 53 more discounted, quality-adjusted years of life expectancy than does no transplantation. This finding is robust even with varying baseline assumptions. CONCLUSIONS: These results support the use of early unrelated donor bone marrow transplantation for most patients with CML.     

Linear Bijections and the Fast Fourier Transform

 Fast Fourier transform algorithms rely upon the choice of certain bijective mappings between the indices of the data arrays. The two basic mappings used in the literature lead to Cooley–Tukey algorithms or to prime factor algorithms. But many other bijections also lead to FFT algorithms, and a complete classification of these mappings is provided. One particular choice leads to a new FFT algorithm that generalizes the prime factor algorithm. It has the advantage of reducing the floating point operation count by reducing the number of trigonometric function evaluations. A certain equivalence relation is defined on the set of bijections that lead to FFT algorithms, and its connection with isomorphism classes of group extensions is studied. Under this equivalence relation every equivalence class contains bijections leading to an FFT algorithm of the new type. Received October 27, 1994; revised version January 25, 1996     

A requirement for the rac1 GTPase in the signal transduction pathway leading to cardiac myocyte hypertrophy

We have used adenoviral-mediated gene transfer of a constitutively active (V12rac1) and dominant negative (N17rac1) isoform of rac1 to assess the role of this small GTPase in cardiac myocyte hypertrophy. Expression of V12rac1 in neonatal cardiac myocytes results in sarcomeric reorganization and an increase in cell size that is indistinguishable from ligand-stimulated hypertrophy. In addition, V12rac1 expression leads to an increase in atrial natriuretic peptide secretion. In contrast, expression of N17rac1, but not a truncated form of Raf-1, attenuated the morphological hypertrophy associated with phenylephrine stimulation. Consistent with the observed effects on morphology, expression of V12rac1 resulted in an increase in new protein synthesis, while N17rac1 expression inhibited phenylephrine-induced leucine incorporation. These results suggest rac1 is an essential element of the signaling pathway leading to cardiac myocyte hypertrophy.     

Fitting multidimensional data using gradient penalties and the sparse grid combination technique

Sparse grids, combined with gradient penalties provide an attractive tool for regularised least squares fitting. It has earlier been found that the combination technique, which builds a sparse grid function using a linear combination of approximations on partial grids, is here not as effective as it is in the case of elliptic partial differential equations. We argue that this is due to the irregular and random data distribution, as well as the proportion of the number of data to the grid resolution. These effects are investigated both in theory and experiments. As part of this investigation we also show how overfitting arises when the mesh size goes to zero. We conclude with a study of modified “optimal” combination coefficients who prevent the amplification of the sampling noise present while using the original combination coefficients.     

Securing QoS signaling in IP-based military Ad Hoc networks

QoS qualifiers in the IP header are prone to attacks. Malicious modifications may lead to theft of service as well as denial of service. Standard IPsec does not cover these header fields, leaving them prone to attacks. The article proposes a variant of the IPsec authentication header that includes protection of these fields. The solution is designed for single-domain networks with planned origin, such as military ad hoc networks.     

Range restriction, outliers, and the use of the Graduate Record Examination to predict graduate school performance.

Comments on the article by R. J. Sternberg and W. M. Williams (see record 1997-04591-002) regarding the empirical validity of the Graduate Record Examination in predicting graduate student performance in psychology. It is contended that the article by Sternberg and Williams offered some interesting suggestions for alternative predictors for graduate school. In addition, the distinctions that Sternberg made in the triarchic theory of intelligence have theoretical and practical utility. Unfortunately, the data presented in the article are seriously flawed and weaken the arguments that are made. Further, it is not clear that Sternberg and Williams's data, as presented, can be interpreted. (PsycINFO Database Record (c) 2010 APA, all rights reserved)