CONTROL OF MOTOR UNITS DURING VOLUNTARY FORCE-PRODUCTION: IMPLICATIONS FOR EXERCISE

We have recently developed a technology that enables studies of the firing properties of a large set (typically 30 to 40) of concurrently active motor units during isometric voluntary contractions ranging from low force levels to maximal voluntary contractions (MVC). With this technology we have executed studies to investigate the behavior of the firing rates of motor units as a function of their recruitment properties during contractions at various force levels. We found that the firing rates have a hierarchical structure wherein the firing rate value of motor units is inversely related to their recruitment threshold, with earlier recruited motor units having greater firing rates at any time and any force level during a contraction. This relationship does not support the opposite notion that has been generally held for the past five decades. Knowing the structure of the firing behavior of motor units during voluntary contractions provides guidance for understanding the performance of muscles during exercise and sports

The Parallel Persistent Memory Model

We consider a parallel computational model that consists of $P$ processors, each with a fast local ephemeral memory of limited size, and sharing a large persistent memory. The model allows for each processor to fault with bounded probability, and possibly restart. On faulting all processor state and local ephemeral memory are lost, but the persistent memory remains. This model is motivated by upcoming non-volatile memories that are as fast as existing random access memory, are accessible at the granularity of cache lines, and have the capability of surviving power outages. It is further motivated by the observation that in large parallel systems, failure of processors and their caches is not unusual. Within the model we develop a framework for developing locality efficient parallel algorithms that are resilient to failures. There are several challenges, including the need to recover from failures, the desire to do this in an asynchronous setting (i.e., not blocking other processors when one fails), and the need for synchronization primitives that are robust to failures. We describe approaches to solve these challenges based on breaking computations into what we call capsules, which have certain properties, and developing a work-stealing scheduler that functions properly within the context of failures. The scheduler guarantees a time bound of $O(W/P_A + D(P/P_A) \lceil\log_{1/f} W\rceil)$ in expectation, where $W$ and $D$ are the work and depth of the computation (in the absence of failures), $P_A$ is the average number of processors available during the computation, and $f \le 1/2$ is the probability that a capsule fails. Within the model and using the proposed methods, we develop efficient algorithms for parallel sorting and other primitives.Comment: This paper is the full version of a paper at SPAA 2018 with the same nam

Serializability, not Serial: Concurrency Control and Availability in Multi-Datacenter Datastores

We present a framework for concurrency control and availability in multi-datacenter datastores. While we consider Google's Megastore as our motivating example, we define general abstractions for key components, making our solution extensible to any system that satisfies the abstraction properties. We first develop and analyze a transaction management and replication protocol based on a straightforward implementation of the Paxos algorithm. Our investigation reveals that this protocol acts as a concurrency prevention mechanism rather than a concurrency control mechanism. We then propose an enhanced protocol called Paxos with Combination and Promotion (Paxos-CP) that provides true transaction concurrency while requiring the same per instance message complexity as the basic Paxos protocol. Finally, we compare the performance of Paxos and Paxos-CP in a multi-datacenter experimental study, and we demonstrate that Paxos-CP results in significantly fewer aborted transactions than basic Paxos.Comment: VLDB201

Heme Oxygenase Induction Suppresses Hepatic Hepcidin and Rescues Ferroportin and Ferritin Expression in Obese Mice

Hepcidin, a phase II reactant secreted by hepatocytes, regulates cellular iron levels by increasing internalization of ferroportin-a transmembrane protein facilitating egress of cellular iron. Chronic low-grade inflammatory states, such as obesity, have been shown to increase oxidative stress and enhance hepcidin secretion from hepatocytes and macrophages. Heme-heme oxygenase (HO) is a stress response system which reduces oxidative stress. We investigated the effects of HO-1 induction on hepatic hepcidin levels and on iron homeostasis in hepatic tissues from lean and obese mice. Obese mice exhibited hyperglycemia (p < 0.05); increased levels of proinflammatory cytokines (MCP-1, IL-6, p < 0.05); oxidative stress (p < 0.05); and increased hepatic hepcidin levels (p < 0.05). Enhancement of hepcidin was reflected in the reduced expression of ferroportin in obese mice (p < 0.05). However, this effect is accompanied by a significant decline in ferritin expression. Additionally, there are reduced insulin receptor phosphorylation and attenuation of metabolic regulators pAMPK, pAKT, and pLKB1. Cobalt protoporphyrin- (CoPP-) induced HO-1 upregulation in obese mice reversed these alterations (p < 0.05), while attenuating hepatic hepcidin levels. These effects of CoPP were prevented in obese mice concurrently exposed to an inhibitor of HO (SnMP) (p < 0.05). Our results highlight a modulatory effect of HO on iron homeostasis mediated through the suppression of hepatic hepcidin

LCA of hospital solid waste treatment alternatives in a developing country: The case of District Swat, Pakistan

Improper management of hospital waste leads to serious health and environmental issues, particularly in the case of developing countries, where, often, applied technologies are obsolete and there is a lack of compliance with respect to international best practices. The present study is designed to assess the environmental impacts of hospital waste management practices in Swath District, Pakistan. For this purpose, a life-cycle assessment (LCA) is applied for the estimation of different impacts of current and alternative hospital solid waste (HSW) treatment practices. Two scenarios are used to describe the current alternative practices (Scenario A and Scenario B), referring either to incineration or to direct landfilling of HSW without any sorting of collected materials. Conversely, Scenario C, which includes the use of pyrolysis and chemical disinfection, are considered as an up-to-date alternative, based on current international recommendations in this field. Prior to the analysis of impacts, due to the lack of available information, data were directly collected from both government and private hospitals in District Swat, involving measurements and a characterization of collected waste. In parallel, interviews were conducted, involving the hospitals' personnel. With respect to waste generation, government hospitals produce a larger amount of waste (74%) compared to private hospitals (24%). Poor regulatory indications and the absence of clear obligations for collection, disposal and management still represent a first obstacle to implement good practices. After defining the boundary of the system and the functional unit, according to standardized LCA practices, a life-cycle impact assessment (LCIA) was conducted, considering eight impact categories: human toxicity, freshwater eco-toxicity, marine aquatic eco-toxicity, terrestrial eco-toxicity, acidification potential, climate change, eutrophication and photochemical oxidation. The current practices (Scenario A and Scenario B) turned out to be the worst for all categories. In particular, the largest impact of all is recorded for human toxicity generated by incineration. In parallel, it must be considered that, currently, no recycling or reusing practices are implemented. Conversely, Scenario C (alternative up-to-date practices) would generate lower impacts. In detail, the highest value was recorded for marine aquatic ecotoxicity in relation to pyrolysis. Applying Scenario C, it would be possible to recover some materials, such as plastics, paper and sharps. In detail, considering the observed compositional characteristics, it would be possible to recover up to 78% of sharps and recycle 41% of plastic and paper from the general waste stream. Moreover, energy could be recovered from the pyrolysis process, generating a further benefit for the surrounding area. A lack of awareness, knowledge and infrastructures prevents the application of correct management practices, further degrading life and environmental conditions of this remote region of Pakistan. The huge difference in impacts between current practices and alternatives is demonstrated, showing a clear alternative for future management plans in this remote region and supporting future actions for local policymakers and hospital managers

pNaKtide Attenuates Steatohepatitis and Atherosclerosis by Blocking Na/K-ATPase/ROS Amplification in C57BI6 and ApoE Knockout Mice Fed a Western Diet

We have previously reported that the alpha1 subunit of sodium potassium adenosine triphosphatase (Na/K-ATPase), acts as a receptor and an amplifier for reactive oxygen species, in addition to its distinct pumping function. On this background, we speculated that blockade of Na/K-ATPase-induced ROS amplification with a specific peptide, pNaKtide, might attenuate the development of steatohepatitis. To test this hypothesis, pNaKtide was administered to a murine model of NASH: the C57Bl6 mouse fed a western diet containing high amounts of fat and fructose. The administration of pNaKtide reduced obesity as well as hepatic steatosis, inflammation and fibrosis. Of interest, we also noted marked improvement in mitochondrial fatty acid oxidation, insulin sensitivity, dyslipidemia and aortic streaking in this mouse model. To further elucidate the effects of pNaKtide on atherosclerosis, similar studies were performed in ApoE knockout mice also exposed to the western diet. In these mice, pNaKtide not only improved steatohepatitis, dyslipidemia, and insulin sensitivity, but also ameliorated significant aortic atherosclerosis. Collectively, this study demonstrates that the Na/K-ATPase/ROS amplification loop contributes significantly to the development and progression of steatohepatitis and atherosclerosis. And furthermore, this study presents a potential treatment, the pNaKtide, for the metabolic syndrome phenotype

Digital Signal Processing

Contains reports on twelve research projects.U. S. Navy - Office of Naval Research (Contract N00014-75-C-0951)National Science Foundation (Grant ENG76-24117)National Aeronautics and Space Administration (Grant NSG-5157)Joint Services Electronics Program (Contract DAABO7-76-C-1400)U.S. Navy-Office of Naval Research (Contract N00014-77-C-0196)Woods Hole Oceanographic InstitutionU. S. Navy - Office of Naval Research (Contract N00014-75-C-0852)Department of Ocean Engineering, M.I.T.National Science Foundation subcontract to Grant GX 41962 to Woods Hole Oceanographic Institutio

Digital Signal Processing Research Program

Contains table of contents for Section 2, an introduction, reports on twenty-two research projects and a list of publications.Sanders, a Lockheed-Martin Corporation Contract BZ4962U.S. Army Research Laboratory Contract DAAL01-96-2-0001U.S. Navy - Office of Naval Research Grant N00014-93-1-0686National Science Foundation Grant MIP 95-02885U.S. Navy - Office of Naval Research Grant N00014-96-1-0930National Defense Science and Engineering FellowshipU.S. Air Force - Office of Scientific Research Grant F49620-96-1-0072U.S. Navy - Office of Naval Research Grant N00014-95-1-0362National Science Foundation Graduate Research FellowshipAT&T Bell Laboratories Graduate Research FellowshipU.S. Army Research Laboratory Contract DAAL01-96-2-0002National Science Foundation Graduate FellowshipU.S. Army Research Laboratory/Advanced Sensors Federated Lab Program Contract DAAL01-96-2-000