Immunological characteristics of HIV-infected children: relationship to age, CD4 counts, disease progression, and survival

We have evaluated immunologic markers of disease progression in 79 children perinatally infected with HIV. Laboratory testing included T lymphocyte subsets and lymphoproliferative responses (LPR) to mitogens (PHA, Con A, and PWM), antigens (Candida, Tetanus), and alloantigens (MLC). Patients were graded into grades I, II, and III based on results of CD4 counts, and into grades A, B, and C based on results of LPR, with grades I and grades A being normal, III and C being the lowest, and II and B falling in-between. CD4 counts, CD4/CD8 ratio, and lymphoproliferative responses were markedly decreased in a majority of children. Grade III CD4 counts were almost always associated with decreased LPR. A majority of the children with grade I CD4 numbers, however, also had abnormal lymphoproliferative responses. Results of laboratory testing were analyzed in relation to clinical disease progression and survival. The first AIDS defining illnesses (ADI), especially opportunistic infections (OI), was usually associated with Grade III/C results in immunologic assays. Survival was significantly decreased in children with grade III CD4 cell counts, and grade C LPR, and was poorest if these abnormalities developed within the first year of life. In this latter age group, if the CD4 counts fell to grade III, the risk for dying was at least five times greater than those children with higher CD4 counts (grades II and I); if the proliferative responses to PHA and MLC were in Grade C, the survival was 22 months. Severe immune defects in the first year of life in children with HIV infection, as assessed by CD4 counts and a battery of functional tests, predicted rapid disease progression.     

A framework for meta-level control in multi-agent systems

Sophisticated agents operating in open environments must make decisions that efficiently trade off the use of their limited resources between dynamic deliberative actions and domain actions. This is the meta-level control problem for agents operating in resource-bounded multi-agent environments. Control activities involve decisions on when to invoke and the amount to effort to put into scheduling and coordination of domain activities. The focus of this paper is how to make effective meta-level control decisions. We show that meta-level control with bounded computational overhead allows complex agents to solve problems more efficiently than current approaches in dynamic open multi-agent environments. The meta-level control approach that we present is based on the decision-theoretic use of an abstract representation of the agent state. This abstraction concisely captures critical information necessary for decision making while bounding the cost of meta-level control and is appropriate for use in automatically learning the meta-level control policies.     

A consumer test of bull vs steer beef

Previous studies of the acceptability of bull beef have relied on laboratory panel or mechanical tests. This study extends the assessment to a consumer panel who cooked and ate the conventionally prepared steaks in their own homes. The test showed consumers to distinguish bull steaks as leaner than steer steaks but not to discriminate on overall appearance. When it came to eating, however, bull steaks were judged to take longer to brown and be less satisfactory in terms of flavour, juiciness, tenderness and overall eating quality. On tenderness 11% of the sample marked the bull steaks as ?well below average’?. These results are sufficiently clear to suggest the need for a test of their commercial impact.     

Energy and the Environment: The Devil and the EPA

The late comedian Flip Wilson had a wildly popular television show back in the 1970s, and one of his most famous characters was “Geraldine Jones” (really, Wilson dressed in drag). Geraldine, an oft-misbehaving young “lady,” had a famous catchphrase, “The devil made me do it!”     

Energy and the environment: How will EPA's newest regulations affect electric markets?

Last December, the US Environmental Protection Agency (EPA) put the finishing touches on new regulations to reduce emissions of mercury and other air toxics, primarily from coal-fired power plants. 1 Regulations targeting coal-fired power plants are nothing new, really, as coal has been Public Enemy No. 1 for many environmentalists and environmental regulators for many years. The air toxics rule joins several others, including rules governing movements of air pollutants between states, disposal of coal ash, and discharges of cooling water.