Attention Enhances the Retrieval and Stability of Visuospatial and Olfactory Representations in the Dorsal Hippocampus

Attention enhances the encoding and retrieval of olfactory and visuospatial representations by modulating place field stability, firing rate, and neuronal synchronization of pyramidal cells in the hippocampus

Salivary Glucose Oxidase from Caterpillars Mediates the Induction of Rapid and Delayed-Induced Defenses in the Tomato Plant

Caterpillars produce oral secretions that may serve as cues to elicit plant defenses, but in other cases these secretions have been shown to suppress plant defenses. Ongoing work in our laboratory has focused on the salivary secretions of the tomato fruitworm, Helicoverpa zea. In previous studies we have shown that saliva and its principal component glucose oxidase acts as an effector by suppressing defenses in tobacco. In this current study, we report that saliva elicits a burst of jasmonic acid (JA) and the induction of late responding defense genes such as proteinase inhibitor 2 (Pin2). Transcripts encoding early response genes associated with the JA pathway were not affected by saliva. We also observed a delayed response to saliva with increased densities of Type VI glandular trichomes in newly emerged leaves. Proteomic analysis of saliva revealed glucose oxidase (GOX) was the most abundant protein identified and we confirmed that it plays a primary role in the induction of defenses in tomato. These results suggest that the recognition of GOX in tomato may represent a case for effector-triggered immunity. Examination of saliva from other caterpillar species indicates that saliva from the noctuids Spodoptera exigua and Heliothis virescens also induced Pin2 transcripts

Trace processors: Exploiting hierarchy and speculation

In high-performance processors, increasing the number of instructions fetched and executed in parallel is becoming increasingly complex, and the peak bandwidth is often underutilized due to control and data dependences. A trace processor 1) efficiently sequences through programs in large units, called traces, and allocates trace-sized units of work to distributed processing elements (PEs), and 2) uses aggressive speculation to par-tially alleviate the effects of control and data dependences. A trace is a dynamic sequence of instructions, typically 16 to 32 instructions in length, which embeds any number of taken or not-taken branch instructions. The hierarchical, trace-based approach to increas-ing parallelism overcomes basic inefficiencies of managing fetch and execution resources on an individual instruction basis. This thesis shows the trace processor is a good microarchitecture for implementing wide-issue machines. Three key points support this conclusion. 1. Trace processors perform better than wide-issue superscalar counterparts because they deliver high instruction throughput without significantly increasing cycle time. Th

Exploiting large ineffectual instruction sequences

A processor executes the full dynamic instruction stream in order to compute the final output of a program, yet we observe equivalent, smaller instruction streams that produce the same cor-rect output. Based on this observation, we attempt to identify large, dynamically-contiguous regions of instructions that are ineffectual as a whole: they either contain no writes, writes that are never referenced, or writes that do not modify the value of a location. The architectural impli-cation is that instruction fetch/execution can quickly bypass predicted-ineffectual regions, while another thread of control verifies that the implied branch predictions in the region are correct and that the region is truly ineffectual. 1