560 research outputs found
Pádraig Mac a Liondain: bard bhí i stát ins an chrích seo
No full textÓ cheantar an Fheadha i ndeisceart Ard Mhacha don bhfile Pádraig Mac a Liondain. Is féidir dataí a bheatha a bheachtú a bhuíochas ar fhile eile ón Fheadh a bhí comhaimseartha leis, Fearghas Mac an Bheatha (fl. 1700), agus a bhuíochas fós ar ghearrchuntas beathaisnéise le Nioclás Ó Cearnaigh (c. 1802–c. 1865) ina dhiaidh sin in ARÉ LS 23 N 33. Ina thuireamh in ómós dá charaid dar tús ‘A sheanchríoch Fáil, is gnách gach léan ort’, is mar seo a chuir Mac an Bheatha é: Seacht gcéad déag an ré a dheachtaím daoibh, is triocha ina dhiaidh an réim go beacht is trí, ó theacht Mhic Dé dár saoradh go ceart is trí mhí, go Pádraig a dhul a dh’éag, mo léan, san feart faoi liag. Is é ‘an feart’ a ainmnítear in áit eile sa tuireamh céanna ná Cill an Chreagáin in aice le baile Chrois Mhic Lionnáin, Co. Ard Mhacha. D’áitigh Nioclás Ó Cearnaigh gur cailleadh Mac a Liondain ‘in April 1733 in the 68th year of his age’, más fíor, rud a fhágfadh gur timpeall na bliana 1665 a rugadh é.Peer-review status unspecifiedCheckdate as researcher profile gives different book title and publication date? Author states title is: Súgáin an dúchais: aistí ar ghnéithe thraidisiún liteartha Chúige Uladh i gcuimhne ar Dhiarmaid Ó Doibhlin, and a publication date of 30 August 2018 -AC2019-02-07 JG: Author query via UCD Research to please update record by dropping ", 1600-1950" part of the Book title and changing publication date to 1 August 2018 -- have don
The Big Mac Index Two Decades On An Evaluation Of Burgernomics
No full textThe Big Mac Index, introduced by The Economist magazine more than two decades ago, claims to provide the “true value” of a large number of currencies. This paper assesses the economic value of this index. We show that (i) the index suffers from a substantial bias; (ii) once the bias is allowed for, the index tracks exchange rates reasonably well over the medium to longer term in accordance with relative purchasing power parity theory; (iii) the index is at least as good as the industry standard, the random walk model, in predicting future currency values for all but shortterm horizons; and (iv) future nominal exchange rates are more responsive than prices to currency mispricing. While not perfect, at a cost of less than $US10 per year, the index seems to provide good value for money.
The Big Mac Index 21 Years On: An Evaluation of Burgereconomics
No full textThe Big Mac Index, introduced by The Economist magazine 21 years ago, claims to provide the “true value” of a large number of currencies. This paper assesses the economic value of this index. We show that (i) the index suffers from a substantial bias; (ii) once the bias is allowed for, the index tracks exchange rates reasonably well over the medium to longer term in accordance with relative purchasing power parity theory; (iii) the index is at least as good as the industry standard, the random walk model, in predicting future currency values for all but short-term horizons; (iv) future nominal exchange rates are more responsive than prices to currency mispricing, but this split is difficult to determine precisely. While not perfect, at a cost of less than $US10 per year, the index seems to provide good value for money.
Effects of oxidized low density lipoprotein, lipid mediators and statins on vascular cell interactions
No full textThe integrin heterodimer CD11b/CD18 (alpha M beta 2, Mac-1, CR3) expressed on monocytes or polymorphonuclear leukocytes (PMN) is a receptor for iC3b, fibrinogen, heparin, and for intercellular adhesion molecule (ICAM)-1 on endothelium, crucially contributing to vascular cell interactions in inflammation and atherosclerosis. In this report, we summarize our findings on the effects of lipid mediators and lipid-lowering drugs. Exposure of endothelial cells to oxidized low density lipoprotein (oxLDL) induces upregulation of ICAM-1 and increases adhesion of monocytic cells expressing Mac-1. Inhibition experiments show that monocytes use distinct ligands, i.e. ICAM-1 and heparan sulfate proteoglycans for adhesion to oxLDL-treated endothelium. An albumin-transferable oxLDL activity is inhibited by the antioxidant pyrrolidine dithiocarbamate (PDTC), while 8-epi-prostaglandin F2 alpha (8-epi-PGF2 alpha) or lysophosphatidylcholine had no effect, implicating yet unidentified radicals. Sequential adhesive! and signaling events lead to the firm adhesion of rolling PMN on activated and adherent platelets, which may occupy areas of endothelial denudation. Shear resistant arrest of PMN on thrombin-stimulated platelets in flow conditions requires distinct regions of Mac-1, involving its interactions with fibrinogen bound to platelet alpha llb beta 3, and with other platelet ligands. Both arrest and adhesion strengthening under flow are stimulated by platelet-activating factor and leukotriene B4, but not by the chemokine receptor CXCR2. We tested whether Mac-1-dependent monocyte adhesiveness is affected by inhibitors of hydroxy-methylglutaryl-Coenzyme A reductase (statins) which improve morbidity and survival of patients with coronary heart disease. As compared to controls, adhesion of isolated monocytes to endothelium ex vivo was increased in patients with hypercholesterolemia. Treatment with statins decreased total and low density lipoprotein (LDL) cholesterol plasma levels, surface expression of Mac-1, and resulted in a dramatic reduction of Mac,mediated monocyte adhesion to endothelium. The inhibition of monocyte adhesion was reversed by mevalonate but not LDL in vitro,indicating that isoprenoid precursors are crucial for adhesiveness of Mac-1. Such effects may crucially contribute to the clinical benefit of statins, independent of cholesterol-lowering, and may represent a paradigm for novel, anti-inflammatory mechanisms of action by this class of drugs
Mac Programming for Absolute Beginners
No full textWant to learn how to program on your Mac? Not sure where to begin? Best-selling author Wallace Wang will explain how to get started with Cocoa, Objective-C, and Xcode. Whether you are an experienced Windows coder moving to the Mac, or you are completely new to programming, you'll see how the basic design of a Mac OS X program works, how Objective-C differs from other languages you may have used, and how to use the Xcode development environment. Most importantly, you'll learn how to use elements of the Cocoa framework to create windows, store data, and respond to users in your own Mac programs
Aggregation with fragment retransmission for very high-speed WLANs
No full textAbstract—In upcoming very high-speed wireless LANs (WLANs), the physical (PHY) layer rate may reach 600 Mbps. To achieve high efficiency at the medium access control (MAC) layer, we identify fundamental properties that must be satisfied by any CSMA-/CA-based MAC layers and develop a novel scheme called aggregation with fragment retransmission (AFR) that exhibits these properties. In the AFR scheme, multiple packets are aggregated into and transmitted in a single large frame. If errors happen during the transmission, only the corrupted fragments of the large frame are retransmitted. An analytic model is developed to evaluate the throughput and delay performance of AFR over noisy channels and to compare AFR with similar schemes in the literature. Optimal frame and fragment sizes are calculated using this model. Transmission delays are minimized by using a zero-waiting mechanism where frames are transmitted immediately once the MAC wins a transmission opportunity. We prove that zero-waiting can achieve maximum throughput. As a complement to the theoretical analysis, we investigate the impact of AFR on the performance of realistic application traffic with diverse requirements by simulations. We have implemented the AFR scheme in the NS-2 simulator and present detailed results for TCP, VoIP, and HDTV traffic. The AFR scheme described was developed as part of the IEEE 802.11n working group work. The analysis presented here is general enough to be extended to proposed schemes in the upcoming 802.11n standard. Trends indicated in this paper should extend to any well-designed aggregation schemes
MAC protocol adaptation in cognitive radio networks
No full textThis thesis presents an adaptive MAC (AMAC) protocol for supporting MAC layer adaptation in cognitive radio networks. MAC protocol adaptation is motivated by the exibility of emerging software-de ned radios which make it feasible to dynamically adjust radio protocols and parameters in order to maintain communications quality. Dynamic changes to the MAC layer may be useful in tactical or vehicular networking scenarios, where radio node density, tra c volumes and service requirements can vary widely over time. A speci c control framework for the proposed AMAC algorithm is described based on the "CogNet" protocol stack which uses a Global Control Plane (GCP) to distribute control information between nearby radios. An AMAC prototype which switches between CSMA and TDMA is evaluated for various tra c scenarios using the NS-2 simulator. In addition, a proof-of-concept AMAC is implemented using GNUradio/USRP platforms on the ORBIT radio grid testbed. Detailed simulation and experimental results are given for both UDP and TCP tra c with di erent usage scenarios and application models. The results show that AMAC can provide improved performance relative to a conventional static system and can be implemented with reasonable control protocol overhead and latency.M.S.Includes bibliographical referencesby Kuo-Chun Huan
UW-MAC: An underwater sensor network MAC protocol
No full textAs over 70percent of the earth's surface is covered by water, it is desirable to deploy underwater sensor networks (UWSNs) to support oceanic research.UWSNs use acoustic waves and are characterized by long and variable propagation delays, intermittent connectivity, limited bandwidth and low bit rates. Energy savings have always been the primary concern in wireless sensor network protocols; however, there are applications where the latency and throughput are prioritized over energy efficiency and are so significant that the application would not be able to satisfy its requirements without them.Although existing dutycycle MAC protocols are power efficient, they introduce significant end-to-end delivery latency, provide poor throughput and are not suitable for the challenging environment of a UWSN. In this paper, we utilize CDMA as the underlying multiple access technique, due to its resilience to multi-path and Doppler's effects prevalent in underwater environments. We propose UW-MAC, a CDMA-based power-controlled medium access protocol that uses both transmitter-based and receiver-based CDMA inside a formed cluster, and uses a TDMA schedule to make the clusterheads communicate with the base station. Our MAC algorithm targets the latency and throughput needs in addition to its ability to increase the overall network lifetime. We discuss the design of UW-MAC, and provide a head-to-head comparison with other protocols through extensive simulations focusing on the performance in terms of latency, throughput, and energy consumption. Copyright © 2009 John Wiley and Sons, Ltd.BERTOSSI AA, 1995, IEEE ACM T NETWORK, V3, P441, DOI 10.1109-90.413218; De S, 2004, IEEE J SEL AREA COMM, V22, P1271, DOI 10.1109-JSAC.2004.829364; GRILO A, 2006, P PERF CONTR WIR SEN; Hu LM, 1993, IEEE ACM T NETWORK, V1, P668, DOI 10.1109-90.266055; JAYASHREE S, 2004, INT C MOB COMP PHIL, P360; Liu BH, 2004, GLOB TELECOMM CONF, P33; Liu CH, 2002, P AMER CONTR CONF, P3003; LU G, 2004, P WMAN SANT FE NM; Molins M., 2006, P IEEE OCEANS 06 AS; MUQATTASH A, 2003, 4 ACM INT S MOB AD H, P153; Peleato Borja, 2006, WUWNET 06, P113; Rhee I., 2005, P 3 INT C EMB NETW S, P90, DOI 10.1145-1098918.1098929; Rice J, 2005, P INT C UND AC MEAS; RODOPLU V, 2005, P IEEE OCEANS 05 C B; SOUSA ES, 1988, IEEE T COMMUN, V36, P272, DOI 10.1109-26.1453; van Dam T., 2003, INT C EMB NETW SENS, P171; VANHOESEL LFW, 2006, TRCTIT0647 U TWENT, P1381; WANG L, 2007, P INT C WIR COMM NET, P2440; Xie G., 2000, TRCS0002 NAV POSTGR; YANG Y, 2005, P 2 INT C BROADB NET, V1, P464; YE W, 2002, ENERGY EFFICIENT MAC, P1567; Ye Wei, 2006, P 4 ACM C EMB NETW S66
Measurement of the ratio of prompt χ c to J / ψ production in pp collisions at √s = 7 TeV
No full textThe prompt production of charmonium χ c and J / ψ states is studied in proton-proton collisions at a centre-of-mass energy of √s = 7 TeV at the Large Hadron Collider. The χ c and J / ψ mesons are identified through their decays χ c → J / ψ γ and J / ψ → μ + μ - using 36 pb - 1 of data collected by the LHCb detector in 2010. The ratio of the prompt production cross-sections for χ c and J / ψ, σ (χ c → J / ψ γ) / σ (J / ψ), is determined as a function of the J / ψ transverse momentum in the range 2 < p T J / ψ < 15 GeV / c. The results are in excellent agreement with next-to-leading order non-relativistic expectations and show a significant discrepancy compared with the colour singlet model prediction at leading order, especially in the low p T J / ψ region
Correction to: Ten weeks of branched-chain amino acid supplementation improves select performance and immunological variables in trained cyclists
No full textClick on the DOI link to access the article (may not be free).Correction:
The authors claim that their names were incorrectly listed on PubMed.
For the author R. Mac Thompson, the first name should be R. Mac and the last name should be Thompson. On SpringerLink the name is listed correctly, but on PubMed he is listed as Mac Thompson R.
For another author C. Brooks Mobley, the first name should be C. Brooks and the last name should be Mobley. On SpringerLink the name is listed correctly, but on PubMed he is listed as Brooks Mobley C.Reagent costs and participant compensation costs were paid through a contract awarded to M.D.R. through MusclePharm Corp. (Denver, CO). B.N. and R.D.A were supported in part by funding from NIH R01 EB016100
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