840 research outputs found
Warfare, Fiscal Capacity, and Performance
We exploit differences in casualties sustained in pre-modern wars to estimate the impact of fiscal capacity on economic performance. In the past, states fought different amounts of external conflicts, of various lengths and magnitudes. To raise the revenues to wage wars, states made fiscal innovations, which persisted and helped to shape current fiscal institutions. Economic historians claim that greater fiscal capacity was the key long-run institutional change brought about by historical conflicts. Using casualties sustained in pre-modern wars to instrument for current fiscal institutions, we estimate substantial impacts of fiscal capacity on GDP per worker. The results are robust to a broad range of specifications, controls, and sub-samples
ULEEN: A Novel Architecture for Ultra Low-Energy Edge Neural Networks
The deployment of AI models on low-power, real-time edge devices requires
accelerators for which energy, latency, and area are all first-order concerns.
There are many approaches to enabling deep neural networks (DNNs) in this
domain, including pruning, quantization, compression, and binary neural
networks (BNNs), but with the emergence of the "extreme edge", there is now a
demand for even more efficient models. In order to meet the constraints of
ultra-low-energy devices, we propose ULEEN, a model architecture based on
weightless neural networks. Weightless neural networks (WNNs) are a class of
neural model which use table lookups, not arithmetic, to perform computation.
The elimination of energy-intensive arithmetic operations makes WNNs
theoretically well suited for edge inference; however, they have historically
suffered from poor accuracy and excessive memory usage. ULEEN incorporates
algorithmic improvements and a novel training strategy inspired by BNNs to make
significant strides in improving accuracy and reducing model size. We compare
FPGA and ASIC implementations of an inference accelerator for ULEEN against
edge-optimized DNN and BNN devices. On a Xilinx Zynq Z-7045 FPGA, we
demonstrate classification on the MNIST dataset at 14.3 million inferences per
second (13 million inferences/Joule) with 0.21 s latency and 96.2%
accuracy, while Xilinx FINN achieves 12.3 million inferences per second (1.69
million inferences/Joule) with 0.31 s latency and 95.83% accuracy. In a
45nm ASIC, we achieve 5.1 million inferences/Joule and 38.5 million
inferences/second at 98.46% accuracy, while a quantized Bit Fusion model
achieves 9230 inferences/Joule and 19,100 inferences/second at 99.35% accuracy.
In our search for ever more efficient edge devices, ULEEN shows that WNNs are
deserving of consideration.Comment: 14 pages, 14 figures Portions of this article draw heavily from
arXiv:2203.01479, most notably sections 5E and 5F.
Novel role for the innate immune receptor toll-like receptor 4 (TLR4) in the regulation of the wnt signaling pathway and photoreceptor apoptosis
Recent evidence has implicated innate immunity in regulating neuronal survival in the brain during stroke and other neurodegenerations. Photoreceptors are specialized light-detecting neurons in the retina that are essential for vision. In this study, we investigated the role of the innate immunity receptor TLR4 in photoreceptors. TLR4 activation by lipopolysaccharide (LPS) significantly reduced the survival of cultured mouse photoreceptors exposed to oxidative stress. With respect to mechanism, TLR4 suppressed Wnt signaling, decreased phosphorylation and activation of the Wnt receptor LRP6, and blocked the protective effect of the Wnt3a ligand. Paradoxically, TLR4 activation prior to oxidative injury protected photoreceptors, in a phenomenon known as preconditioning. Expression of TNFα and its receptors TNFR1 and TNFR2 decreased during preconditioning, and preconditioning was mimicked by TNFα antagonists, but was independent of Wnt signaling. Therefore, TLR4 is a novel regulator of photoreceptor survival that acts through the Wnt and TNFα pathways. © 2012 Yi et al
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MEF2C-MYOCD and Leiomodin1 Suppression by miRNA-214 Promotes Smooth Muscle Cell Phenotype Switching in Pulmonary Arterial Hypertension.
BACKGROUND: Vascular hyperproliferative disorders are characterized by excessive smooth muscle cell (SMC) proliferation leading to vessel remodeling and occlusion. In pulmonary arterial hypertension (PAH), SMC phenotype switching from a terminally differentiated contractile to synthetic state is gaining traction as our understanding of the disease progression improves. While maintenance of SMC contractile phenotype is reportedly orchestrated by a MEF2C-myocardin (MYOCD) interplay, little is known regarding molecular control at this nexus. Moreover, the burgeoning interest in microRNAs (miRs) provides the basis for exploring their modulation of MEF2C-MYOCD signaling, and in turn, a pro-proliferative, synthetic SMC phenotype. We hypothesized that suppression of SMC contractile phenotype in pulmonary hypertension is mediated by miR-214 via repression of the MEF2C-MYOCD-leiomodin1 (LMOD1) signaling axis. METHODS AND RESULTS: In SMCs isolated from a PAH patient cohort and commercially obtained hPASMCs exposed to hypoxia, miR-214 expression was monitored by qRT-PCR. miR-214 was upregulated in PAH- vs. control subject hPASMCs as well as in commercially obtained hPASMCs exposed to hypoxia. These increases in miR-214 were paralleled by MEF2C, MYOCD and SMC contractile protein downregulation. Of these, LMOD1 and MEF2C were directly targeted by the miR. Mir-214 overexpression mimicked the PAH profile, downregulating MEF2C and LMOD1. AntagomiR-214 abrogated hypoxia-induced suppression of the contractile phenotype and its attendant proliferation. Anti-miR-214 also restored PAH-PASMCs to a contractile phenotype seen during vascular homeostasis. CONCLUSIONS: Our findings illustrate a key role for miR-214 in modulation of MEF2C-MYOCD-LMOD1 signaling and suggest that an antagonist of miR-214 could mitigate SMC phenotype changes and proliferation in vascular hyperproliferative disorders including PAH
Microarray Analysis of Human Monocytes Infected with Francisella tularensis Identifies New Targets of Host Response Subversion
Francisella tularensis is a gram-negative facultative bacterium that causes the disease tularemia, even upon exposure to low numbers of bacteria. One critical characteristic of Francisella is its ability to dampen or subvert the host immune response. In order to help understand the mechanisms by which this occurs, we performed Affymetrix microarray analysis on transcripts from blood monocytes infected with the virulent Type A Schu S4 strain. Results showed that expression of several host response genes were reduced such as those associated with interferon signaling, Toll-like receptor signaling, autophagy and phagocytosis. When compared to microarrays from monocytes infected with the less virulent F. tularensis subsp. novicida, we found qualitative differences and also a general pattern of quantitatively reduced pro-inflammatory signaling pathway genes in the Schu S4 strain. Notably, the PI3K / Akt1 pathway appeared specifically down-regulated following Schu S4 infection and a concomitantly lower cytokine response was observed. This study identifies several new factors potentially important in host cell subversion by the virulent Type A F. tularensis that may serve as novel targets for drug discovery
Extraordinary room-temperature photoluminescence in WS2 monolayers
Individual monolayers of metal dichalcogenides are atomically thin
two-dimensional crystals with attractive physical properties different from
their bulk layered counterpart. Here we describe the direct synthesis of WS2
monolayers with triangular morphologies and strong room-temperature
photoluminescence (PL). Bulk WS2 does not present PL due to its indirect band
gap nature. The edges of these monolayers exhibit PL signals with extraordinary
intensity, around 25 times stronger than the platelets center. The structure
and composition of the platelet edges appear to be critical for the PL
enhancement effect. Electron diffraction revealed that platelets present zigzag
edges, while first-principles calculations indicate that sulfur-rich zigzag WS2
edges possess metallic edge states, which might tailor the optical response
reported here. These novel 2D nanoscale light sources could find diverse
applications including the fabrication of flexible/transparent/low-energy
optoelectronic devices
The Role of Galectin-1 and Galectin-3 in the Mucosal Immune Response to Citrobacter rodentium Infection
Despite their abundance at gastrointestinal sites, little is known about the role of galectins in gut immune responses. We have therefore investigated the Citrobacter rodentium model of colonic infection and inflammation in Galectin-1 or Galectin-3 null mice. Gal-3 null mice showed a slight delay in colonisation after inoculation with C. rodentium and a slight delay in resolution of infection, associated with delayed T cell, macrophage and dendritic cell infiltration into the gut mucosa. However, Gal-1 null mice also demonstrated reduced T cell and macrophage responses to infection. Despite the reduced T cell and macrophage response in Gal-1 null mice, there was no effect on C. rodentium infection kinetics and pathology. Overall, Gal-1 and Gal-3 play only a minor role in immunity to a gut bacterial pathogen
Polycomb Group Protein Bmi1 Is Required for Growth of RAF Driven Non-Small-Cell Lung Cancer
Background: We have previously described a RAF oncogene driven transgenic mouse model for non small cell lung cancer (NSCLC). Here we examine whether tumor initiation and growth requires the stem cell self-renewal factor Bmi1. Principal Findings: In order to evaluate Bmi1 function in NSCLC two founder lines that differ in incidence and latency of tumor formation were compared. Ablation of Bmi1 expression in both lines had a dramatically decreased tumor growth. As the line with shorter latency matched the life span of Bmi1 knock out mice, these mice were chosen for further study. The absence of Bmi1 did not decrease the number of tumor initiation in these mice as only the size and not the number of tumors decreased. Reduction in tumor growth resulted from an increase in cell death and decrease in cell cycle progression that corresponded with up-regulation of the p16 INK4a and p19 ARF. Significance: The data identifies Bmi1 as an important factor for expansion but not initiation of RAF driven NSCLC
Protective Effect of Curcumin on Pulmonary and Cardiovascular Effects Induced by Repeated Exposure to Diesel Exhaust Particles in Mice
Particulate air pollution has been associated with increased risk of cardiopulmonary diseases. However, the underlying mechanisms are not fully understood. We have previously demonstrated that single dose exposure to diesel exhaust particle (DEP) causes lung inflammation and peripheral thrombotic events. Here, we exposed mice with repeated doses of DEP (15µg/animal) every 2nd day for 6 days (a total of 4 exposures), and measured several cardiopulmonary endpoints 48 h after the end of the treatments. Moreover, the potential protective effect of curcumin (the yellow pigment isolated from turmeric) on DEP-induced cardiopulmonary toxicity was assessed. DEP exposure increased macrophage and neutrophil numbers, tumor necrosis factor α (TNF α) in the bronchoalveolar lavage (BAL) fluid, and enhanced airway resistance to methacoline measured invasively using Flexivent. DEP also significantly increased plasma C-reactive protein (CRP) and TNF α concentrations, systolic blood pressure (SBP) as well as the pial arteriolar thrombosis. It also significantly enhanced the plasma D-dimer and plasminogen activator inhibitor-1 (PAI-1). Pretreatment with curcumin by oral gavage (45 mg/kg) 1h before exposure to DEP significantly prevented the influx of inflammatory cells and the increase of TNF α in BAL, and the increased airway resistance caused by DEP. Likewise, curcumin prevented the increase of SBP, CRP, TNF α, D-dimer and PAI-1. The thrombosis was partially but significantly mitigated. In conclusion, repeated exposure to DEP induced lung and systemic inflammation characterized by TNFα release, increased SBP, and accelerated coagulation. Our findings indicate that curcumin is a potent anti-inflammatory agent that prevents the release of TNFα and protects against the pulmonary and cardiovascular effects of DEP
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