Predictive Coding Strategies for Developmental Neurorobotics

In recent years, predictive coding strategies have been proposed as a possible means by which the brain might make sense of the truly overwhelming amount of sensory data available to the brain at any given moment of time. Instead of the raw data, the brain is hypothesized to guide its actions by assigning causal beliefs to the observed error between what it expects to happen and what actually happens. In this paper, we present a variety of developmental neurorobotics experiments in which minimalist prediction error-based encoding strategies are utilize to elucidate the emergence of infant-like behavior in humanoid robotic platforms. Our approaches will be first naively Piagian, then move onto more Vygotskian ideas. More specifically, we will investigate how simple forms of infant learning, such as motor sequence generation, object permanence, and imitation learning may arise if minimizing prediction errors are used as objective functions

Through-silicon-via aware interconnect prediction and optimization for 3D stacked ICs

Individual dies in 3D integrated circuits are connected using through-silicon-vias (TSVs). TSVs not only increase manufacturing cost, but also incur silicon area, delay, and power overhead. However, the effects of TSV overheads have not been studied thoroughly in the literature. In this paper, we analyze the impact of TSVs on silicon area and wirelength. We derive a new 3D wirelength distri-bution model considering TSV size. Based on this new prediction model, we explain the impact of several design parameters newly introduced in 3D ICs. We also present a case study to show how the model can help make early design decisions for 3D ICs

Cellular energy stress induces AMPK-mediated regulation of YAP and the Hippo pathway.

YAP (Yes-associated protein) is a transcription co-activator in the Hippo tumour suppressor pathway and controls cell growth, tissue homeostasis and organ size. YAP is inhibited by the kinase Lats, which phosphorylates YAP to induce its cytoplasmic localization and proteasomal degradation. YAP induces gene expression by binding to the TEAD family transcription factors. Dysregulation of the Hippo-YAP pathway is frequently observed in human cancers. Here we show that cellular energy stress induces YAP phosphorylation, in part due to AMPK-dependent Lats activation, thereby inhibiting YAP activity. Moreover, AMPK directly phosphorylates YAP Ser 94, a residue essential for the interaction with TEAD, thus disrupting the YAP-TEAD interaction. AMPK-induced YAP inhibition can suppress oncogenic transformation of Lats-null cells with high YAP activity. Our study establishes a molecular mechanism and functional significance of AMPK in linking cellular energy status to the Hippo-YAP pathway

Comparative effects of norepinephrine and vasopressin on internal thoracic arterial graft flow after off-pump coronary artery bypass grafting

ObjectiveVasoconstrictors such as norepinephrine and vasopressin are commonly used to raise the blood pressure during myocardial revascularization. The internal thoracic artery is commonly used for coronary artery grafting because of its long-term patency. However, the internal thoracic artery is a living conduit that responds to vasoactive substances. The objective of this study was to measure change in internal thoracic arterial flow after infusion of norepinephrine or vasopressin.MethodsForty-one patients undergoing elective off-pump coronary artery bypass grafting participated in this study. After the median sternotomy, the left internal thoracic artery was dissected with a pedicle and grafted to the left anterior descending artery. After all anastomoses were performed and hemodynamic parameters were stable, the grafted internal thoracic arterial blood flow was measured by transit time flowmeter on the distal portion of the graft as a baseline. Norepinephrine or vasopressin was then infused until mean arterial pressure was increased to 20% of baseline. Graft flow and hemodynamic variables were measured when mean arterial pressure reached the intended level.ResultsBaseline grafted internal thoracic arterial flows were similar (norepinephrine 57.1 ± 17.7 mL min−1, vasopressin 66.0 ± 34.3 mL min−1). With norepinephrine, flow increased significantly relative to baseline (77.2 ± 31.0 mL min−1); with vasopressin, it remained unchanged (68.3 ± 37.0 mL min−1).ConclusionsFor patients needing vasopressor support after coronary artery bypass grafting, norepinephrine appeared superior to vasopressin because of increased internal thoracic arterial flow

Block-level Designs of Die-to-Wafer Bonded 3D ICs and Their Design Quality Tradeoffs

Abstract-In 3D ICs, block-level designs provide various advantages over designs done at other granularity such as gate-level because they promote the reuse of IP blocks. In this paper, we study block-level 3D-IC designs, where the footprint of the dies in the stack are different. This happens in case of die-to-wafer bonding, which is more popular choice for near-term low-cost 3D designs. We study design quality tradeoffs among three different ways to place through-silicon vias (TSVs): TSV-farm, TSV-distributed, and TSV-whitespace. In our holistic approach, we use wirelength, power, performance, temperature, and mechanical stress metrics to conduct comprehensive comparative studies on the three design styles. In addition, we provide analysis on the impact of TSV size and pitch on the design quality of these three styles

Mst1-FoxO Signaling Protects Naïve T Lymphocytes from Cellular Oxidative Stress in Mice

Background: The Ste-20 family kinase Hippo restricts cell proliferation and promotes apoptosis for proper organ development in Drosophila. InC. elegans, Hippo homolog also regulates longevity. The mammalian Ste20-like protein kinase, Mst1, plays a role in apoptosis induced by various types of apoptotic stress. Mst1 also regulates peripheral naïve T cell trafficking and proliferation in mice. However, its functions in mammals are not fully understood. Methodology/Principal Findings: Here, we report that the Mst1-FoxO signaling pathway plays a crucial role in survival, but not apoptosis, of naïve T cells. In Mst1 2/2 mice, peripheral T cells showed impaired FoxO1/3 activation and decreased FoxO protein levels. Consistently, the FoxO targets, Sod2 and catalase, were significantly down-regulated in Mst1 2/2 T cells, thereby resulting in elevated levels of intracellular reactive oxygen species (ROS) and induction of apoptosis. Expression of constitutively active FoxO3a restored Mst1 2/2 T cell survival. Crossing Mst1 transgenic mice (Mst1 Tg) with Mst1 2/2 mice reduced ROS levels and restored normal numbers of peripheral naïve T cells in Mst1 Tg;Mst1 2/2 progeny. Interestingly, peripheral T cells from Mst1 2/2 mice were hypersensitive to c-irradiation and paraquat-induced oxidative stresses, whereas those from Mst1 Tg mice were resistant. Conclusions/Significance: These data support the hypothesis that tolerance to increased levels of intracellular RO