Physics with WASA-at-COSY

DOE Office of Scientific and Technical Information (OSTI.GOV)

Schadmand, Susan

2010-12-28

The WASA detector facility is an internal experiment at the COoler SYnchrotron COSY in Juelich, Germany. The COSY accelerator provides proton and deuteron beams with momenta up to 3.7 GeV/c giving access to hadron physics including the strange quark sector. The WASA-at-COSY physics program focuses on light meson decays where rare decays are used to scrutinize symmetries and symmetry breaking. The structure of hadrons is probed with transition form factors and hadron spectroscopy while hadron dynamics is studied via reaction dynamics and few body reactions. Goals and status are reported with special emphasis on the meson Dalitz decays.

Short-term effects of hydrated lime and quicklime on the decay of human remains using pig cadavers as human body analogues: Laboratory experiments.

PubMed

Schotsmans, Eline M J; Denton, John; Fletcher, Jonathan N; Janaway, Robert C; Wilson, Andrew S

2014-05-01

Contradictions and misconceptions regarding the effect of lime on the decay of human remains have demonstrated the need for more research into the effect of different types of lime on cadaver decomposition. This study follows previous research by the authors who have investigated the effect of lime on the decomposition of human remains in burial environments. A further three pig carcasses (Sus scrofa), used as human body analogues, were observed and monitored for 78 days without lime, with hydrated lime (Ca(OH)2) and with quicklime (CaO) in the taphonomy laboratory at the University of Bradford. The results showed that in the early stages of decay, the unlimed and hydrated lime cadavers follow a similar pattern of changes. In contrast, the application of quicklime instigated an initial acceleration of decay. Microbial investigation demonstrated that the presence of lime does not eliminate all aerobic bacteria. The experiment also suggested that lime functions as a sink, buffering the carbon dioxide evolution. This study complements the field observations. It has implications for the investigation of time since death of limed remains. Knowledge of the effects of lime on decomposition processes is of interest to forensic pathologists, archaeologists, humanitarian organisations and those concerned with disposal of animal carcasses or human remains in mass disasters. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

The Search for a Non-Superallowed Branch in the β decay of ^38mK

NASA Astrophysics Data System (ADS)

Leach, Kyle; Bandyopadhyay, D.; Finlay, P.; Garrett, P. E.; Grinyer, G. F.; Phillips, A. A.; Schumaker, M. A.; Svensson, C. E.; Wong, J.; Ball, G. C.; Bassiachvilli, E.; Ettenauer, S.; Hackman, G.; Morton, A. C.; Mythili, S.; Newman, O.; Pearson, C. J.; Pearson, M. R.; Savajols, H.; Leslie, J. R.; Melconian, D.; Austin, R. A. E.; Barton, C.

2007-10-01

The study presented is part of an experimental program exploring the properties of superallowed Fermi β decays conducted at the Isotope Separator and Accelerator (ISAC) facility at TRIUMF in Vancouver, B.C. Canada. Using the 8π γ-ray spectrometer and the Scintillating Electron Positron Tagging Array (SCEPTAR), it was possible to set a new upper limit on an unobserved non-analogue branch in the decay of ^38mK. This branch is expected to be extremely weak, and the removal of contaminant isobaric decays and background radiation in the spectra was thus exceedingly important during the analysis. Our work has reduced the previous upper limit by approximately a factor of two and is approaching the theoretically predicted branching ratio.

Efficient production by sperm-mediated gene transfer of human decay accelerating factor (hDAF) transgenic pigs for xenotransplantation

PubMed Central

Lavitrano, Marialuisa; Bacci, Maria Laura; Forni, Monica; Lazzereschi, Davide; Di Stefano, Carla; Fioretti, Daniela; Giancotti, Paola; Marfé, Gabriella; Pucci, Loredana; Renzi, Luigina; Wang, Hongjun; Stoppacciaro, Antonella; Stassi, Giorgio; Sargiacomo, Massimo; Sinibaldi, Paola; Turchi, Valeria; Giovannoni, Roberto; Della Casa, Giacinto; Seren, Eraldo; Rossi, Giancarlo

2002-01-01

A large number of hDAF transgenic pigs to be used for xenotransplantation research were generated by using sperm-mediated gene transfer (SMGT). The efficiency of transgenesis obtained with SMGT was much greater than with any other method. In the experiments reported, up to 80% of pigs had the transgene integrated into the genome. Most of the pigs carrying the hDAF gene transcribed it in a stable manner (64%). The great majority of pigs that transcribed the gene expressed the protein (83%). The hDAF gene was transmitted to progeny. Expression was stable and found in caveolae as it is in human cells. The expressed gene was functional based on in vitro experiments performed on peripheral blood mononuclear cells. These results show that our SMGT approach to transgenesis provides an efficient procedure for studies involving large animal models. PMID:12393815

Response of the human vestibulo-ocular reflex system to constant angular acceleration. I. Theoretical study.

PubMed

Boumans, L J; Rodenburg, M; Maas, A J

1983-01-01

The response of the human vestibulo-ocular reflex system to a constant angular acceleration is calculated using a second order model with an adaptation term. After first reaching a maximum the peracceleratory response declines. When the stimulus duration is long the decay is mainly governed by the adaptation time constant Ta, which enables to reliably estimate this time constant. In the postacceleratory period of constant velocity there is a reversal in response. The magnitude and the time course of the per- and postacceleratory response are calculated for various values of the cupular time constant T1, the adaptation time constant Ta, and the stimulus duration, thus enabling their influence to be assessed.

Elongation factor Ts directly facilitates the formation and disassembly of the Escherichia coli elongation factor Tu·GTP·aminoacyl-tRNA ternary complex.

PubMed

Burnett, Benjamin J; Altman, Roger B; Ferrao, Ryan; Alejo, Jose L; Kaur, Navdep; Kanji, Joshua; Blanchard, Scott C

2013-05-10

Aminoacyl-tRNA (aa-tRNA) enters the ribosome in a ternary complex with the G-protein elongation factor Tu (EF-Tu) and GTP. EF-Tu·GTP·aa-tRNA ternary complex formation and decay rates are accelerated in the presence of the nucleotide exchange factor elongation factor Ts (EF-Ts). EF-Ts directly facilitates the formation and disassociation of ternary complex. This system demonstrates a novel function of EF-Ts. Aminoacyl-tRNA enters the translating ribosome in a ternary complex with elongation factor Tu (EF-Tu) and GTP. Here, we describe bulk steady state and pre-steady state fluorescence methods that enabled us to quantitatively explore the kinetic features of Escherichia coli ternary complex formation and decay. The data obtained suggest that both processes are controlled by a nucleotide-dependent, rate-determining conformational change in EF-Tu. Unexpectedly, we found that this conformational change is accelerated by elongation factor Ts (EF-Ts), the guanosine nucleotide exchange factor for EF-Tu. Notably, EF-Ts attenuates the affinity of EF-Tu for GTP and destabilizes ternary complex in the presence of non-hydrolyzable GTP analogs. These results suggest that EF-Ts serves an unanticipated role in the cell of actively regulating the abundance and stability of ternary complex in a manner that contributes to rapid and faithful protein synthesis.

Insights into the Effects of Complement Factor H on the Assembly and Decay of the Alternative Pathway C3 Proconvertase and C3 Convertase*

PubMed Central

Bettoni, Serena; Bresin, Elena; Remuzzi, Giuseppe; Noris, Marina; Donadelli, Roberta

2016-01-01

The activated fragment of C3 (C3b) and factor B form the C3 proconvertase (C3bB), which is cleaved by factor D to C3 convertase (C3bBb). Older studies (Conrad, D. H., Carlo, J. R., and Ruddy, S. (1978) J. Exp. Med. 147, 1792–1805; Pangburn, M. K., and Müller-Eberhard, H. J. (1978) Proc. Natl. Acad. Sci. U.S.A. 75, 2416–2420; Kazatchkine, M. D., Fearon, D. T., and Austen, K. F. (1979) J. Immunol. 122, 75–81) indicated that the complement alternative pathway regulator factor H (FH) competes with factor B for C3b binding; however, the capability of FH to prevent C3bB assembly has not been formally investigated. Moreover, in the few published studies FH did not favor C3bB dissociation. Whether FH may affect C3bBb formation from C3bB is unknown. We set up user-friendly assays based on combined microplate/Western blotting techniques that specifically detect either C3bB or C3bBb, with the aim of investigating the effect of FH on C3bB assembly and decay and C3bBb formation and decay. We document that FH does not affect C3bB assembly, indicating that FH does not efficiently compete with factor B for C3b binding. We also found that FH does not dissociate C3bB. FH showed a strong C3bBb decay-accelerating activity, as reported previously, and also exerted an apparent inhibitory effect on C3bBb formation. The latter effect was not fully attributable to a rapid FH-mediated dissociation of C3bBb complexes, because blocking decay with properdin and C3 nephritic factor did not restore C3bBb formation. FH almost completely prevented release of the smaller cleavage subunit of FB (Ba), without modifying the amount of C3bB complexes, suggesting that FH inhibits the conversion of C3bB to C3bBb. Thus, the inhibitory effect of FH on C3bBb formation is likely the sum of inhibition of C3bB conversion to C3bBb and of C3bBb decay acceleration. Further studies are required to confirm these findings in physiological cell-based settings. PMID:26903516

Protective Effects of Decay-Accelerating Factor on Blast-Induced Neurotrauma in Rats

DTIC Science & Technology

2013-08-16

gelatin -Veronal buffer (pH 7.3). After centrifugation, absorbance of the supernatant was determined at 405 nm, and the serum concentration inducing 50...Houston, TX 78234, USA. 2Department of Trauma and Resuscitation Medicine, Naval Medical Research Center, 503 Robert Grant Avenue, Silver Spring, MD

Lattice Gauge Theories Within and Beyond the Standard Model

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gelzer, Zechariah John

The Standard Model of particle physics has been very successful in describing fundamental interactions up to the highest energies currently probed in particle accelerator experiments. However, the Standard Model is incomplete and currently exhibits tension with experimental data for interactions involvingmore » $B$~mesons. Consequently, $B$-meson physics is of great interest to both experimentalists and theorists. Experimentalists worldwide are studying the decay and mixing processes of $B$~mesons in particle accelerators. Theorists are working to understand the data by employing lattice gauge theories within and beyond the Standard Model. This work addresses the theoretical effort and is divided into two main parts. In the first part, I present a lattice-QCD calculation of form factors for exclusive semileptonic decays of $B$~mesons that are mediated by both charged currents ($$B \\to \\pi \\ell \

Porcine Knock-in Fibroblasts Expressing hDAF on α-1,3-Galactosyltransferase (GGTA1) Gene Locus.

PubMed

Kim, Ji Woo; Kim, Hye-Min; Lee, Sang Mi; Kang, Man-Jong

2012-10-01

The Galactose-α1,3-galactose (α1,3Gal) epitope is responsible for hyperacute rejection in pig-to-human xenotransplantation. Human decay-accelerating factor (hDAF) is a cell surface regulatory protein that serves as a complement inhibitor to protect self cells from complement attack. The generation of α1,3-galactosyltransferase (GGTA1) knock-out pigs expressing DAF is a necessary step for their use as organ donors for humans. In this study, we established GGTA1 knock-out cell lines expressing DAF from pig ear fibroblasts for somatic cell nuclear transfer. hDAF expression was detected in hDAF knock-in heterozygous cells, but not in normal pig cells. Expression of the GGTA1 gene was lower in the knock-in heterozygous cell line compared to the normal pig cell. Knock-in heterozygous cells afforded more effective protection against cytotoxicity with human serum than with GGTA1 knock-out heterozygous and control cells. These cell lines may be used in the production of GGTA1 knock-out and DAF expression pigs for xenotransplantation.

Incorporation of Prior Knowledge of Signal Behavior Into the Reconstruction to Accelerate the Acquisition of Diffusion MRI Data.

PubMed

Abascal, Juan F P J; Desco, Manuel; Parra-Robles, Juan

2018-02-01

Diffusion MRI data are generally acquired using hyperpolarized gases during patient breath-hold, which yields a compromise between achievable image resolution, lung coverage, and number of -values. In this paper, we propose a novel method that accelerates the acquisition of diffusion MRI data by undersampling in both the spatial and -value dimensions and incorporating knowledge about signal decay into the reconstruction (SIDER). SIDER is compared with total variation (TV) reconstruction by assessing its effect on both the recovery of ventilation images and the estimated mean alveolar dimensions (MADs). Both methods are assessed by retrospectively undersampling diffusion data sets ( =8) of healthy volunteers and patients with Chronic Obstructive Pulmonary Disease (COPD) for acceleration factors between x2 and x10. TV led to large errors and artifacts for acceleration factors equal to or larger than x5. SIDER improved TV, with a lower solution error and MAD histograms closer to those obtained from fully sampled data for acceleration factors up to x10. SIDER preserved image quality at all acceleration factors, although images were slightly smoothed and some details were lost at x10. In conclusion, we developed and validated a novel compressed sensing method for lung MRI imaging and achieved high acceleration factors, which can be used to increase the amount of data acquired during breath-hold. This methodology is expected to improve the accuracy of estimated lung microstructure dimensions and provide more options in the study of lung diseases with MRI.

Neutron Detector Signal Processing to Calculate the Effective Neutron Multiplication Factor of Subcritical Assemblies

DOE Office of Scientific and Technical Information (OSTI.GOV)

Talamo, Alberto; Gohar, Yousry

2016-06-01

This report describes different methodologies to calculate the effective neutron multiplication factor of subcritical assemblies by processing the neutron detector signals using MATLAB scripts. The subcritical assembly can be driven either by a spontaneous fission neutron source (e.g. californium) or by a neutron source generated from the interactions of accelerated particles with target materials. In the latter case, when the particle accelerator operates in a pulsed mode, the signals are typically stored into two files. One file contains the time when neutron reactions occur and the other contains the times when the neutron pulses start. In both files, the timemore » is given by an integer representing the number of time bins since the start of the counting. These signal files are used to construct the neutron count distribution from a single neutron pulse. The built-in functions of MATLAB are used to calculate the effective neutron multiplication factor through the application of the prompt decay fitting or the area method to the neutron count distribution. If the subcritical assembly is driven by a spontaneous fission neutron source, then the effective multiplication factor can be evaluated either using the prompt neutron decay constant obtained from Rossi or Feynman distributions or the Modified Source Multiplication (MSM) method.« less

Decay-accelerating Factor Limits Hemorrhage-instigated Tissue Injury and Improves Resuscitation Clinical Parameters

DTIC Science & Technology

2012-10-29

thicknesswithacryostat andfixed incoldmethanol for 20min. The fixed sections were permeabilized with 0.2% Triton X-100 in PBS for 10min, then blockedwith 2% bovine ...J Inflamm 1998;48:13. [31] Garratty G. Blood group antigens as tumor markers, parasitic /bacterial/viral receptors, and their association with

Acceleration from short-duration blast

NASA Astrophysics Data System (ADS)

Ritzel, D. V.; Van Albert, S.; Sajja, V.; Long, J.

2018-01-01

The blast-induced motion of spheres has been studied experimentally where the shock wave is rapidly decaying during the period that quasi-steady acceleration would be developed in the case of a step-function shock wave as considered in most shock-tube studies. The motion of sphere models ranging from 39 to 251 mm in diameter and having a range of densities was assessed using the "free-flight" method in a simulator specially designed to replicate the decaying shock wave profile of spherical blast including negative phase and positive entropy gradient. A standardized blast-wave simulation of 125 kPa and 6-ms positive-phase duration was applied for all experiments. In all cases, there are three phases to the motion: a relatively low "kickoff" velocity from the shock diffraction, acceleration or deceleration during the positive duration, then deceleration through the negative phase and subsequent quiescent air. The unexpected deceleration of larger spheres after their kickoff velocity during the decaying yet high-speed flow of the blast wave seems associated with the persistence of a ring vortex on the downstream side of the sphere. The flow is entirely unsteady with initial forces dominated by the shock diffraction; therefore, the early motion of spheres under such conditions is not governed by quasi-steady drag as in classical aerodynamics. The work will help establish scaling rules for model studies of blast-induced motion relevant to improvised explosive devices, and preliminary results are shown for motion imparted to a human skull surrogate.

Therapeutic inhibition of the complement system. Y2K update.

PubMed

Asghar, S S; Pasch, M C

2000-09-01

Activation of complement is an essential part of the mechanism of pathogenesis of a large number of human diseases; its inhibition by pharmacological means is likely to suppress disease processes in complement mediated diseases. From this point of view low molecular weight synthetic inhibitors of complement are being developed and high molecular weight natural inhibitors of human origin present in plasma or embedded in cell membrane are being purified or produced in their recombinant forms. This review is concerned with high molecular weight inhibitors, some of which are already in clinical use but may be efficacious in many other diseases in which they have not yet been tried. C1-esterase inhibitor (C1-INH) concentrate prepared from human plasma is being successfully used for the treatment of hereditary angioneurotic edema. Recently, C1-INH has been found to be consumed in severe inflammation and has been shown to exert beneficial effects in several inflammatory conditions such as human sepsis, post-operative myocardial dysfunction due to reperfusion injury, severe capillary leakage syndrome after bone marrow transplantation, reperfusion injury after lung transplantation, burn, and cytotoxicity caused by IL-2 therapy in cancer. Factor I has been used for the treatment of factor I deficiency. Recombinant soluble forms of membrane cofactor protein (MCP), and decay accelerating factor (DAF) have not yet been tried in humans but have been shown to be effective in immune complex mediate inflammation in animals. Organs of pigs transgenic for one or more of human membrane regulators of complement namely membrane cofactor protein (MCP), decay accelerating factor (DAF) or CD59, are being produced for transplantation into humans. They have been shown to be resistant to hyperacute rejection in non-human primates; acute vascular rejection is still a problem in their clinical use. It is hoped that these observations together with future developments will make xeno-transplantation in clinical practice a reality. Several recombinant variants of complement receptor 1 (CR1) have been produced. The most effective of these appears to be sCR1-SLe x, sCR1 part of which inhibits complement and carbohydrate Sle x moiety inhibits selectin mediated interactions of neutrophils and lymphocytes with endothelium. Although clinical trials of sCR1 in humans is eagerly awaited, several of the recombinant versions of sCR1 have been shown to suppress ischemia/reperfusion injury, thermal trauma, and immune complex mediated inflammation. They have also been shown to be effective in experimental models of systemic sclerosis, arthritis, myasthenia gravis, Guillain Barré syndrome and glomerulonephritis. Intravenous immunoglobulin, three of the most prominent properties of which are neutralization of autoantibody activity, suppression of autoantibody production and inhibition of complement activity, is being used in several diseases. These include autoimmune thrombocyopenic purpura, Kawasaki disease and several neurological diseases such as myasthenia gravis and Guillain Barre syndrome. In many uncontrolled small scale studies intravenous immunoglobulin has been shown to be effective in many immunological including dermatological diseases; controlled clinical trials in a large number of patients with these diseases is needed to establish the efficacy. It is hoped that in future therapeutic inhibition of complement will be one of the major approaches to combat many human diseases.

Selective expression of a splice variant of decay-accelerating factor in c-erbB-2-positive mammary carcinoma cells showing increased transendothelial invasiveness

DOE Office of Scientific and Technical Information (OSTI.GOV)

Brandt, Burkhard; Mikesch, Jan-Hendrik; Simon, Ronald

2005-04-01

By differential-display-PCR a subclone of the SK-BR-3 cell line with high in vitro transendothelial invasiveness was identified to express increased levels of a new alternative splice variant of decay-accelerating factor (DAF). DAF seems to play an important role in some malignant tumours since on the one hand the expression of complement inhibitors on the surface of tumour cells prevents the accumulation of complement factors and in consequence cell lysis. On the other hand, DAF has been identified as a ligand for the CD97 surface receptor which induces cell migration. Immunofluorescence procedures, Western blot analyses, and cDNA clone sequencing were employedmore » to confirm the expression of DAF restricted to invasive tumour cells. Using a radioactive RNA-in situ hybridisation on freshly frozen tissue microarrays and RT-PCR on native tumour tissue, the expression of alternative spliced DAF mRNA was demonstrated in invasive breast cancer. Due to the fact that it could thereby not be detected in normal mammary tissues, it has to be confirmed in larger studies that the DAF splice variant might be a specific tumour marker for invasive breast cancer.« less

Evidence of soluble microbial products accelerating chloramine decay in nitrifying bulk water samples.

PubMed

Bal Krishna, K C; Sathasivan, Arumugam; Chandra Sarker, Dipok

2012-09-01

The discovery of a microbially derived soluble product that accelerates chloramine decay is described. Nitrifying bacteria are believed to be wholly responsible for rapid chloramine loss in drinking water systems. However, a recent investigation showed that an unidentified soluble agent significantly accelerated chloramine decay. The agent was suspected to be either natural organic matter (NOM) or soluble microbial products (SMPs). A laboratory scale reactor was fed chloraminated reverse osmosis (RO) treated water to eliminate the interference from NOM. Once nitrification had set in, experiments were conducted on the reactor and feed waters to determine the identity of the component. The study showed the presence of SMPs released by microbes in severely nitrified waters. Further experiments proved that the SMPs significantly accelerated chloramine decay, probably through catalytic reaction. Moreover, application of common protein denaturing techniques stopped the reaction implying that the compound responsible was likely to be a protein. This significant finding will pave the way for better control of chloramine in the distribution systems. Copyright © 2012 Elsevier Ltd. All rights reserved.

Low micronutrient intake may accelerate the degenerative diseases of aging through allocation of scarce micronutrients by triage

PubMed Central

Ames, Bruce N.

2006-01-01

Inadequate dietary intakes of vitamins and minerals are widespread, most likely due to excessive consumption of energy-rich, micronutrient-poor, refined food. Inadequate intakes may result in chronic metabolic disruption, including mitochondrial decay. Deficiencies in many micronutrients cause DNA damage, such as chromosome breaks, in cultured human cells or in vivo. Some of these deficiencies also cause mitochondrial decay with oxidant leakage and cellular aging and are associated with late onset diseases such as cancer. I propose DNA damage and late onset disease are consequences of a triage allocation response to micronutrient scarcity. Episodic shortages of micronutrients were common during evolution. Natural selection favors short-term survival at the expense of long-term health. I hypothesize that short-term survival was achieved by allocating scarce micronutrients by triage, in part through an adjustment of the binding affinity of proteins for required micronutrients. If this hypothesis is correct, micronutrient deficiencies that trigger the triage response would accelerate cancer, aging, and neural decay but would leave critical metabolic functions, such as ATP production, intact. Evidence that micronutrient malnutrition increases late onset diseases, such as cancer, is discussed. A multivitamin-mineral supplement is one low-cost way to ensure intake of the Recommended Dietary Allowance of micronutrients throughout life. PMID:17101959

Mapping of binding epitopes of a human decay-accelerating factor monoclonal antibody capable of enhancing rituximab-mediated complement-dependent cytotoxicity.

PubMed

Guo, Bo; Ma, Zheng-wei; Li, Hua; Xu, Gui-lian; Zheng, Ping; Zhu, Bo; Wu, Yu-Zhang; Zou, Qiang

2008-08-01

Complement-dependent cytotoxicity (CDC) is thought to be one of the most important mechanisms of action of therapeutic monoclonal antibodies (mAbs). The decay-accelerating factor (DAF) overexpressed in certain tumors limits the CDC effect of the therapeutic anticancer antibodies. The use of DAF blocking antibodies targeted specifically at cancer cells in combination with immunotherapeutic mAbs of cancer may improve the therapeutic effect in cancer patients. In this study, the lysis of Raji cells mediated by CDC was determined after blocking DAF function by anti-DAF polyclonal antibody and 3 mAbs (DG3, DG9, DA11) prepared in our laboratory, respectively, in the presence of the anti-CD20 chimeric mAb rituximab. The binding domains of the three anti-DAF mAbs were identified using yeast surface display technique, and the mimic epitopes of mAb DG3 were screened from a random phage-display nonapeptide library. The results showed that blocking DAF function by anti-DAF polyclonal antibody enhanced complement-mediated killing of Raji cells. Among the 3 mAbs against DAF, only DG3 was found to be able to remarkably enhance the CDC effect of the therapeutic mAb rituximab. DG3 bound to the third short consensus repeat (SCR) of DAF. Binding of DG3 to immobilized DAF was inhibited by mimic epitope peptides screened from the peptide library. Our results suggest that a higher level of DAF expressed by certain tumor cells is significant to abolish the CDC effect of therapeutic anticancer antibodies, and mAbs binding to SCR3 can enhance the complement-mediated killing of Raji cells. It is of significance to identify the DAF epitopes required in inhibiting CDC not only for better understanding of the relationship between the structure and function of DAF, but also for designing and developing anti-DAF mAbs capable of enhancing CDC.

Partial characterization of the cross-reacting determinant, a carbohydrate epitope shared by decay accelerating factor and the variant surface glycoprotein of the African Trypanosoma brucei.

PubMed

Shak, S; Davitz, M A; Wolinsky, M L; Nussenzweig, V; Turner, M J; Gurnett, A

1988-03-15

The variant surface glycoprotein (VSG) of the African trypanosome is anchored in the cell membrane by a complex glycan attached to phosphatidylinositol. The carboxyl terminal portion of VSG contains a cryptic carbohydrate epitope, the cross-reacting determinant (CRD), that is revealed only after removal of the diacylglycerol by phosphatidylinositol-specific phospholipase C (PIPLC) or VSG lipase. Recently, we have shown that after hydrolysis by PIPLC, decay-accelerating factor (DAF)--a mammalian phosphatidylinositol-anchored protein--also contains the CRD epitope. Using a two site immunoradiometric assay in which the capturing antibody is a monoclonal antibody to DAF and the revealing antibody is anti-CRD, we now show that sugar phosphates significantly inhibited the binding of anti-CRD antibody to DAF released by PIPLC. DL-myo-inositol 1,2-cyclic phosphate was the most potent inhibitor of binding (IC50 less than 10(-8) M). Other sugar phosphates, such as alpha-D-glucose-1-phosphate, which also possess adjacent hydroxyl and phosphate moieties in cis also inhibited binding at low concentrations (IC50 = 10(-5) to 10(-4) M). In contrast, sugar phosphates which do not possess adjacent hydroxyl and phosphate moieties in cis and simple sugars weakly inhibited binding (IC50 greater than 10(-3) M). These results suggest that myo-inositol 1,2-cyclic phosphate contributes significantly to the epitope recognized by the anti-CRD antibody and is consistent with analysis of the carboxyl terminus of VSG, which also suggested the presence of the cyclic inositol phosphate. In light of the recent findings that human serum contains a glycan-phosphatidyl-inositol-specific phospholipase D, which converts DAF from a hydrophobic to a hydrophilic form lacking the CRD, the observation that the phosphate is crucial for expression of the epitope may be relevant in understanding the origin of CRD-negative DAF in urine and plasma.

Homo sapiens-Specific Binding Site Variants within Brain Exclusive Enhancers Are Subject to Accelerated Divergence across Human Population.

PubMed

Zehra, Rabail; Abbasi, Amir Ali

2018-03-01

Empirical assessments of human accelerated noncoding DNA frgaments have delineated presence of many cis-regulatory elements. Enhancers make up an important category of such accelerated cis-regulatory elements that efficiently control the spatiotemporal expression of many developmental genes. Establishing plausible reasons for accelerated enhancer sequence divergence in Homo sapiens has been termed significant in various previously published studies. This acceleration by including closely related primates and archaic human data has the potential to open up evolutionary avenues for deducing present-day brain structure. This study relied on empirically confirmed brain exclusive enhancers to avoid any misjudgments about their regulatory status and categorized among them a subset of enhancers with an exceptionally accelerated rate of lineage specific divergence in humans. In this assorted set, 13 distinct transcription factor binding sites were located that possessed unique existence in humans. Three of 13 such sites belonging to transcription factors SOX2, RUNX1/3, and FOS/JUND possessed single nucleotide variants that made them unique to H. sapiens upon comparisons with Neandertal and Denisovan orthologous sequences. These variants modifying the binding sites in modern human lineage were further substantiated as single nucleotide polymorphisms via exploiting 1000 Genomes Project Phase3 data. Long range haplotype based tests laid out evidence of positive selection to be governing in African population on two of the modern human motif modifying alleles with strongest results for SOX2 binding site. In sum, our study acknowledges acceleration in noncoding regulatory landscape of the genome and highlights functional parts within it to have undergone accelerated divergence in present-day human population.

Biotic Interactions and Sunlight Affect Persistence of Fecal Indicator Bacteria and Microbial Source Tracking Genetic Markers in the Upper Mississippi River

PubMed Central

McMinn, Brian R.; Shanks, Orin C.; Sivaganesan, Mano; Fout, G. Shay; Ashbolt, Nicholas J.

2014-01-01

The sanitary quality of recreational waters that may be impacted by sewage is assessed by enumerating fecal indicator bacteria (FIB) (Escherichia coli and enterococci); these organisms are found in the gastrointestinal tracts of humans and many other animals, and hence their presence provides no information about the pollution source. Microbial source tracking (MST) methods can discriminate between different pollution sources, providing critical information to water quality managers, but relatively little is known about factors influencing the decay of FIB and MST genetic markers following release into aquatic environments. An in situ mesocosm was deployed at a temperate recreational beach in the Mississippi River to evaluate the effects of ambient sunlight and biotic interactions (predation, competition, and viral lysis) on the decay of culture-based FIB, as well as molecularly based FIB (Entero1a and GenBac3) and human-associated MST genetic markers (HF183 and HumM2) measured by quantitative real-time PCR (qPCR). In general, culturable FIB decayed the fastest, while molecularly based FIB and human-associated genetic markers decayed more slowly. There was a strong correlation between the decay of molecularly based FIB and that of human-associated genetic markers (r2, 0.96 to 0.98; P < 0.0001) but not between culturable FIB and any qPCR measurement. Overall, exposure to ambient sunlight may be an important factor in the early-stage decay dynamics but generally was not after continued exposure (i.e., after 120 h), when biotic interactions tended to be the only/major influential determinant of persistence. PMID:24747902

Li+, Na+ and K+ co-doping effects on scintillation properties of Ce:Gd3Ga3Al2O12 single crystals

NASA Astrophysics Data System (ADS)

Yoshino, Masao; Kamada, Kei; Kochurikhin, Vladimir V.; Ivanov, Mikhail; Nikl, Martin; Okumura, Satoshi; Yamamoto, Seiichi; Yeom, Jung Yeol; Shoji, Yasuhiro; Kurosawa, Shunsuke; Yokota, Yuui; Ohashi, Yuji; Yoshikawa, Akira

2018-06-01

Ce0.5%: Ce:Gd3Ga3Al2O12(GGAG) single crystals co-doped with 500at.ppm Li+, Na+ and K+ were grown by using the micro-pulling down method. The smooth Ce4+ charge transfer absorption below 350 nm and decay time acceleration were observed in Li co-doped sample. Na+ and K+ co-doping did not show a large effect on the acceleration of decay time compared with Li co-doping. Ce0.5%:GGAG single crystals co-doped with 500 at.ppm Li+ were also grown by the Czochralski method. Optical, scintillation properties and timing performance were evaluated to investigate the effect of univalent alkali metal ions co-doping on Ce:GGAG scintillators. The scintillation decay curves were accelerated by Li co-doping: the decay time was significantly accelerated to 54.8 ns (47%) for the faster component and 158 ns (53%) for the slower component. The light output was 94% of the non co-doped Ce:GGAG standard. The coincidence time resolution was improved to 258 ps by Li co-doping.

Revisiting alpha decay-based near-light-speed particle propulsion.

PubMed

Zhang, Wenwu; Liu, Zhen; Yang, Yang; Du, Shiyu

2016-08-01

Interplanet and interstellar travels require long-term propulsion of spacecrafts, whereas the conventional schemes of propulsion are limited by the velocity of the ejected mass. In this study, alpha particles released by nuclear decay are considered as a potential solution for long-time acceleration. The principle of near-light-speed particle propulsion (NcPP) was elucidated and the stopping and range of ions in matter (SRIM) was used to predict theoretical accelerations. The results show that NcPP by means of alpha decay is feasible for long-term spacecraft propulsion and posture adjustment in space. A practical NcPP sail can achieve a speed >150km/s and reach the brink of the solar system faster than a mass equivalent solar sail. Finally, to significantly improve the NcPP sail, the hypothesis of stimulated acceleration of nuclear decay (SAND) was proposed, which may shorten the travel time to Mars to within 20 days. Copyright © 2016 Elsevier Ltd. All rights reserved.

On high b diffusion imaging in the human brain: ruminations and experimental insights.

PubMed

Mulkern, Robert V; Haker, Steven J; Maier, Stephan E

2009-10-01

Interest in the manner in which brain tissue signal decays with b factor in diffusion imaging schemes has grown in recent years following the observation that the decay curves depart from purely monoexponential decay behavior. Regardless of the model or fitting function proposed for characterizing sufficiently sampled decay curves (vide infra), the departure from monoexponentiality spells increased tissue characterization potential. The degree to which this potential can be harnessed to improve specificity, sensitivity and spatial localization of diseases in brain, and other tissues, largely remains to be explored. Furthermore, the degree to which currently popular diffusion tensor imaging methods, including visually impressive white matter fiber "tractography" results, have almost completely ignored the nonmonoexponential nature of the basic signal decay with b factor is worthy of communal introspection. Here we limit our attention to a review of the basic experimental features associated with brain water signal diffusion decay curves as measured over extended b-factor ranges, the simple few parameter fitting functions that have been proposed to characterize these decays and the more involved models, e.g.,"ruminations," which have been proposed to account for the nonmonoexponentiality to date.

On high b diffusion imaging in the human brain: ruminations and experimental insights✩

PubMed Central

Mulkern, Robert V.; Haker, Steven J.; Maier, Stephan E.

2010-01-01

Interest in the manner in which brain tissue signal decays with b factor in diffusion imaging schemes has grown in recent years following the observation that the decay curves depart from purely monoexponential decay behavior. Regardless of the model or fitting function proposed for characterizing sufficiently sampled decay curves (vide infra), the departure from monoexponentiality spells increased tissue characterization potential. The degree to which this potential can be harnessed to improve specificity, sensitivity and spatial localization of diseases in brain, and other tissues, largely remains to be explored. Furthermore, the degree to which currently popular diffusion tensor imaging methods, including visually impressive white matter fiber “tractography” results, have almost completely ignored the nonmonoexponential nature of the basic signal decay with b factor is worthy of communal introspection. Here we limit our attention to a review of the basic experimental features associated with brain water signal diffusion decay curves as measured over extended b-factor ranges, the simple few parameter fitting functions that have been proposed to characterize these decays and the more involved models, e.g.,“ruminations,” which have been proposed to account for the nonmonoexponentiality to date. PMID:19520535

Accelerated Fractional Ventilation Imaging with Hyperpolarized Gas MRI

PubMed Central

Emami, Kiarash; Xu, Yinan; Hamedani, Hooman; Profka, Harrilla; Kadlecek, Stephen; Xin, Yi; Ishii, Masaru; Rizi, Rahim R.

2013-01-01

PURPOSE To investigate the utility of accelerated imaging to enhance multi-breath fractional ventilation (r) measurement accuracy using HP gas MRI. Undersampling shortens the breath-hold time, thereby reducing the O2-induced signal decay and allows subjects to maintain a more physiologically relevant breathing pattern. Additionally it may improve r estimation accuracy by reducing RF destruction of HP gas. METHODS Image acceleration was achieved by using an 8-channel phased array coil. Undersampled image acquisition was simulated in a series of ventilation images and images were reconstructed for various matrix sizes (48–128) using GRAPPA. Parallel accelerated r imaging was also performed on five mechanically ventilated pigs. RESULTS Optimal acceleration factor was fairly invariable (2.0–2.2×) over the range of simulated resolutions. Estimation accuracy progressively improved with higher resolutions (39–51% error reduction). In vivo r values were not significantly different between the two methods: 0.27±0.09, 0.35±0.06, 0.40±0.04 (standard) versus 0.23±0.05, 0.34±0.03, 0.37±0.02 (accelerated); for anterior, medial and posterior slices, respectively, whereas the corresponding vertical r gradients were significant (P < 0.001): 0.021±0.007 (standard) versus 0.019±0.005 (accelerated) [cm−1]. CONCLUSION Quadruple phased array coil simulations resulted in an optimal acceleration factor of ~2× independent of imaging resolution. Results advocate undersampled image acceleration to improve accuracy of fractional ventilation measurement with HP gas MRI. PMID:23400938

Accelerated detection of brown-rot decay : comparison of soil block test, chemical analysis, mechanical properties, and immunodetection

Treesearch

C. A. Clausen; S. N. Kartal

2003-01-01

Early detection of wood decay is critical because decay fungi can cause rapid structural failure. The objective of this study was to compare the sensitivity of different methods purported to detect brown-rot decay in the early stages of development. The immunodiagnostic wood decay (IWD)test, soil block test/cake pan test, mechanical property tests, and chemical...

Homologous species restriction of the complement-mediated killing of nucleated cells.

PubMed Central

Yamamoto, H; Blaas, P; Nicholson-Weller, A; Hänsch, G M

1990-01-01

The homologous restriction of complement (C) lysis is attributed to membrane proteins: decay-accelerating factor (DAF), C8 binding protein (C8bp) and P18/CD59. Since these proteins are also expressed on peripheral blood cells, species restriction was tested for in the complement-mediated killing of antibody-coated human leucocytes by human or rabbit complement. Killing was more efficient when rabbit complement was used. Preincubation of cells with an antibody to DAF abolished the difference. When C1-7 sites were first attached to the cells and either rabbit or human C8, C9 were added, the killing of monocytes and lymphocytes was equally efficient; only in polymorphonuclear neutrophils was a higher efficiency of rabbit C8, C9 seen. Thus, in contrast to haemolysis, restriction occurred predominantly at the C3 level and the action of the terminal complement components was not inhibited. Since C8bp isolated from peripheral blood cells showed essentially similar characteristics as the erythrocyte-derived C8bp, the failure of C8bp to inhibit the action of the terminal components on nucleated cells might reflect differences of the complement membrane interactions between erythrocytes or nucleated cells, respectively. Images Figure 5 PMID:1697561

Altered calcium handling and increased contraction force in human embryonic stem cell derived cardiomyocytes following short term dexamethasone exposure

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kosmidis, Georgios; Bellin, Milena; Ribeiro, Marcelo C.

One limitation in using human pluripotent stem cell derived cardiomyocytes (hPSC-CMs) for disease modeling and cardiac safety pharmacology is their immature functional phenotype compared with adult cardiomyocytes. Here, we report that treatment of human embryonic stem cell derived cardiomyocytes (hESC-CMs) with dexamethasone, a synthetic glucocorticoid, activated glucocorticoid signaling which in turn improved their calcium handling properties and contractility. L-type calcium current and action potential properties were not affected by dexamethasone but significantly faster calcium decay, increased forces of contraction and sarcomeric lengths, were observed in hESC-CMs after dexamethasone exposure. Activating the glucocorticoid pathway can thus contribute to mediating hPSC-CMs maturation.more » - Highlights: • Dexamethasone accelerates Ca{sup 2+} transient decay in hESC-CMs. • Dexamethasone enhances SERCA and NCX function in hESC-CMs. • Dexamethasone increases force of contraction and sarcomere length in hESC-CMs. • Dexamethasone does not alter I{sub Ca,L} and action potential characteristics in hESC-CMs.« less

Neutron-decay Protons from Solar Flares as Seed Particles for CME-shock Acceleration in the Inner Heliosphere

DOE Office of Scientific and Technical Information (OSTI.GOV)

Murphy, Ronald J.; Ko, Yuan-Kuen, E-mail: ronald.murphy@nrl.navy.mil, E-mail: yuan-kuen.ko@nrl.navy.mil

The protons in large solar energetic particle events are accelerated in the inner heliosphere by fast shocks produced by coronal mass ejections. Unless there are other sources, the protons these shocks act upon would be those of the solar wind (SW). The efficiency of the acceleration depends on the kinetic energy of the protons. For a 2000 km s{sup −1} shock, the most effective proton energies would be 30–100 keV; i.e., within the suprathermal tail component of the SW. We investigate one possible additional source of such protons: those resulting from the decay of solar-flare-produced neutrons that escape from themore » Sun into the low corona. The neutrons are produced by interactions of flare-accelerated ions with the solar atmosphere. We discuss the production of low-energy neutrons in flares and their decay on a interplanetary magnetic field line near the Sun. We find that even when the flaring conditions are optimal, the 30–100 keV neutron-decay proton density produced by even a very large solar flare would be only about 10% of that of the 30–100 keV SW suprathermal tail. We discuss the implication of a seed-particle source of more frequent, small flares.« less

Histone mRNA degradation in vivo: the first detectable step occurs at or near the 3' terminus.

PubMed Central

Ross, J; Peltz, S W; Kobs, G; Brewer, G

1986-01-01

The first detectable step in the degradation of human H4 histone mRNA occurs at the 3' terminus in a cell-free mRNA decay system (J. Ross and G. Kobs, J. Mol. Biol. 188:579-593, 1986). Most or all of the remainder of the mRNA is then degraded in a 3'-to-5' direction. The experiments described here were designed to determine whether a similar degradation pathway is followed in whole cells. Two sets of short-lived histone mRNA decay products were detected in logarithmically growing erythroleukemia (K562) cells. These products, designated the -5 and -12 RNAs, were generated by the loss of approximately 4 to 6 and 11 to 13 nucleotides, respectively, from the 3' terminus of histone mRNA. The same decay products were observed after a brief incubation in vitro. They were in low abundance or absent from cells that were not degrading histone mRNA. In contrast, they were readily detectable in cells that degraded the mRNA at an accelerated rate, i.e., in cells cultured with a DNA synthesis inhibitor, either cytosine arabinoside or hydroxyurea. During the initial stages of the decay process, as the 3' terminus of the mRNA was being degraded, the 5'-terminal region remained intact. These results indicate that the first detectable step in human H4 histone mRNA decay occurs at the 3' terminus and that degradation proceeds 3' to 5', both in cells and in cell-free reactions. Images PMID:3467177

Histone mRNA degradation in vivo: the first detectable step occurs at or near the 3' terminus.

PubMed

Ross, J; Peltz, S W; Kobs, G; Brewer, G

1986-12-01

The first detectable step in the degradation of human H4 histone mRNA occurs at the 3' terminus in a cell-free mRNA decay system (J. Ross and G. Kobs, J. Mol. Biol. 188:579-593, 1986). Most or all of the remainder of the mRNA is then degraded in a 3'-to-5' direction. The experiments described here were designed to determine whether a similar degradation pathway is followed in whole cells. Two sets of short-lived histone mRNA decay products were detected in logarithmically growing erythroleukemia (K562) cells. These products, designated the -5 and -12 RNAs, were generated by the loss of approximately 4 to 6 and 11 to 13 nucleotides, respectively, from the 3' terminus of histone mRNA. The same decay products were observed after a brief incubation in vitro. They were in low abundance or absent from cells that were not degrading histone mRNA. In contrast, they were readily detectable in cells that degraded the mRNA at an accelerated rate, i.e., in cells cultured with a DNA synthesis inhibitor, either cytosine arabinoside or hydroxyurea. During the initial stages of the decay process, as the 3' terminus of the mRNA was being degraded, the 5'-terminal region remained intact. These results indicate that the first detectable step in human H4 histone mRNA decay occurs at the 3' terminus and that degradation proceeds 3' to 5', both in cells and in cell-free reactions.

Algorithm for Search and Recovery of the Vertex of Decay in the Hypernuclear Experiment NIS-GIBS at Dubna Nuclotron

DOE Office of Scientific and Technical Information (OSTI.GOV)

Korotkova, Anna M.; Lukstins, Juris

2010-01-05

Search of the decay vertex is an important part of the hypernuclear experiment, carried out of the Dubna nuclotron accelerator. The decay vertex is reconstructed from data from two sets of proportional chambers. The distribution of the vertex of decay of the hypernucleus allows to measure the lifetime of the hypernuclei. Algorithm for searches and automatically calculates the decay vertex has been written.

Wave-function-renormalization effects in resonantly enhanced tunneling

NASA Astrophysics Data System (ADS)

Lörch, N.; Pepe, F. V.; Lignier, H.; Ciampini, D.; Mannella, R.; Morsch, O.; Arimondo, E.; Facchi, P.; Florio, G.; Pascazio, S.; Wimberger, S.

2012-05-01

We study the time evolution of ultracold atoms in an accelerated optical lattice. For a Bose-Einstein condensate with a narrow quasimomentum distribution in a shallow optical lattice the decay of the survival probability in the ground band has a steplike structure. In this regime we establish a connection between the wave-function-renormalization parameter Z introduced by P. Facchi, H. Nakazato, and S. Pascazio [Phys. Rev. Lett.PRLTAO0031-900710.1103/PhysRevLett.86.2699 86, 2699 (2001)] to characterize nonexponential decay and the phenomenon of resonantly enhanced tunneling, where the decay rate is peaked for particular values of the lattice depth and the accelerating force.

Early detection and progression of decay in L-joints and lap-joints in a moderate decay hazard zone

Treesearch

Carol A. Clausen; Terry L. Highley; Daniel L. Lindner

2006-01-01

Accelerated test methods are needed to evaluate the initiation and progression of decay in wood exposed aboveground. The relationship between test conditions and initiation of decay, however, is poorly understood. Southern pine and maple L-joints and lap-joints were exposed aboveground in a configuration that encouraged water entrapment at the Valley View Experimental...

REVIEWS OF TOPICAL PROBLEMS: Ultrahigh-energy neutrinos from astrophysical sources and superheavy particle decays

NASA Astrophysics Data System (ADS)

Ryabov, Vladimir A.

2006-09-01

Problems in the fields of neutrino astronomy and ultrahigh-energy astrophysics are reviewed. Neutrino fluxes produced in various astrophysical sources (bottom-up acceleration scenarios) and resulting from the decay of superheavy particles (top-down scenarios) are considered. Neutrino oscillation processes and the absorption and regeneration of neutrinos inside the earth are analyzed and some other factors affecting the intensity and flavor composition of astrophysical neutrino fluxes are discussed. Details of ultrahigh-energy neutrino interactions are discussed within the Standard Model, as well as using nonstandard scenarios predicting an anomalous increase in the inelastic neutrino-nucleon cross section. Ultrahigh-energy neutrino detection techniques currently in use in new-generation neutrino telescopes and cosmic ray detectors are also discussed.

Implications of the pion-decay gamma emission and neutron observations with CORONAS-F/SONG

NASA Astrophysics Data System (ADS)

Kurt, V.; Yushkov, B.; Kudela, K.

2013-05-01

We analyzed the high-energy gamma and neutron emissions observed by the SONG instrument onboard the CORONAS-F satellite during August 25, 2001, October 28, 2003, November 4, 2003, and January 20, 2005 solar flares. These flares produced neutrons and/or protons recorded near Earth. The SONG response was consistent with detection of the pion-decay gamma emission and neutrons in these events. We compared time profiles of various electromagnetic emissions and showed that the maximum of the pion-decay-emission coincided in time best of all with the soft X-ray derivative, dISXR/dt, maximum. We evaluated the energy of accelerated ions and compared it with the energy deposited by accelerated electrons. The ion energy becomes comparable or even higher than the electron energy from a certain step of flare development. So the time profile of dISXR/dt is a superposition of energy deposited by both fractions of accelerated particles. This result allowed us to use a time profile of dISXR/dt as a real proxy of time behavior of the energy release at least during major flare analysis. In particular the time interval when the dISXR/dt value exceeds 0.9 of its maximum can be used as a unified reference point for the calculations of time delay between the high-energy proton acceleration and GLE onset. Analysis of the total set of pion-decay emission observations shows that such temporal closeness of pion-decay emission maximum and the soft X-ray derivative maximum is typical but not obligatory.

Spectral narrowing and spin echo for localized carriers with heavy-tailed L evy distribution of hopping times

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yue, Z.; Mkhitaryan, Vagharsh; Raikh, M. E.

2016-02-02

We study analytically the free induction decay and the spin echo decay originating from the localized carriers moving between the sites which host random magnetic fields. Due to disorder in the site positions and energies, the on-site residence times, , are widely spread according to the L evy distribution. The power-law tail ∝ τ -1-∝ in the distribution of does not affect the conventional spectral narrowing for α > 2, but leads to a dramatic acceleration of the free induction decay in the domain 2 > α > 1. The next abrupt acceleration of the decay takes place as becomesmore » smaller than 1. In the latter domain the decay does not follow a simple-exponent law. To capture the behavior of the average spin in this domain, we solve the evolution equation for the average spin using the approach different from the conventional approach based on the Laplace transform. Unlike the free induction decay, the tail in the distribution of the residence times leads to the slow decay of the spin echo. The echo is dominated by realizations of the carrier motion for which the number of sites, visited by the carrier, is minimal.« less

On the Numerical Analysis of Decay Rate Enhancement in Metallic Environment

NASA Astrophysics Data System (ADS)

Mehedinteanu, S.

2007-10-01

Motivated on the very recent experiments to determine the acceleration of the alpha decay of meta-stable radionuclides in metallic environment some work has been done to strengthten the importance in the process of electrons screening in metals. Thus, by combining the Gamow decay theory with electrostatic screening in Debye-Hückel approximation (jellium model) a formula for ``the shift'' in screening energy which enters in the decay enhancement factor expression that copes well with these experiments has been derived. It was established that to simulate the poly-atoms system containing decaying isotopes in QM&MD codes calculations, and to include ``the screening energy shift'' of protons, decay alpha, beta+ particles due to all surrounding interacting effects, it is sufficiently only to substitute the code ruly pseudo-potential input for hydrogen-like atoms (including alpha) by a screened Coulomb potential as from the well-known Gamow alpha decay theory. For demonstration is used the QM&MD code package which usually performs density-functional theory (DFT) total-energy calculations for materials ranging from insulators to transition metals. This package employs first-principles pseudo-potentials and a plane-wave basis-set, and it was used to do a special calculus for some metal environments (Pd) where protons-deuterons are implanted or when it is alloyed with a radionuclide-like isotopes (174Hf72), the results compare well with the existing experiments on the decay enhancement. These works give further arguments for a cheap solution to remove the transuranic waste (involving all alpha-decay) of used-up rods of fission reactors in a time period of a few years.

Determining Light Decay Curves in a Plastic Scintillator using Cosmic Ray Muons

NASA Astrophysics Data System (ADS)

Wakwella, Praveen; Mandanas, Sarah; Wilson, John; Visca, Hannah; Padalino, Stephen; Sangster, T. Craig; Regan, Sean P.

2017-10-01

Plastic scintillators are used in ICF research to measure neutron energies via their time of flight (nToF). The energy resolution and sensitivity of an nToF system is directly correlated with the scintillation decay time of the plastic. To decrease the decay time, some scintillators are quenched with oxygen. Consequently, they become less efficient at producing light. As time passes, oxygen defuses out of the scintillator this in turn increases light production and the decay time. Mono-energetic calibration neutrons produced at accelerator facilities can be used to monitor the decreased oxygen content, however this is a time consuming process and requires that the scintillators be removed from the ICF facilities on a regular basis. Here, a possible method for cross calibrating accelerator neutrons with cosmic ray muons is presented. This method characterizes the scintillator with accelerator-generated neutrons and then cross calibrates them with cosmic ray muons. Once the scintillators are redeployed at the ICF facility the oxygen level can be regularly monitored using muons in situ. Funded in part by the United States Department of Energy through a Grant from the Laboratory for Laser Energetics.

The changes of the forests dendroproduction in the Carpathian basin - case study: Quercus petraea

NASA Astrophysics Data System (ADS)

Berki, Imre; Gulyás, Krisztina; Veperdi, Gábor

2017-04-01

There are a lot of publications about the accelerated forest growth in West-and North- Europe due to global climate change, elevated atmospheric carbon-dioxide and nitrogen input. However, in Central-Europe the increasing tendency of extremely dry periods caused mass mortality of forest formed tree species, and triggered slower or indefinite growth trends. In this study our scientific questions were the followings: • Which are the characteristic mechanism in the south-east part of Central -Europe: forest decay, accelerated growth or both? • What are the expected impacts of climate change on sessile oak production? • Are there any differences between a humid and an arid landscapes tree height growth? Method for measuring the changes of growth in humid landscapes: Top height of the stands is a good indicator of the site condition with high stand density. So this indicator can be used to measure the changes of growth in humid stands, where the drought periods caused not considerable tree decay. We have been measured a young and old sessile oak stands next to each other along a humid-arid climatic transect in Hungary. The old stands representing the "pre-climate change" conditions, when the annual temperature means, and the frequency of droughts were lower. The young stands have been lived their whole lifetime in changed atmospheric condition. Compared the top height of the young and old stand to the yield tables we can establish a soft accelerated growth in the last decades in the humid landscapes. Method for measuring the changes of growth in dry landscapes: Top height of thinned forests due to tree decay do not indicate the changed atmospheric condition. Although the volume of the survived trees has been increased (compared to yield tables) due to accelerated diameter growth, the production of the thinned Quercus petraea forests have been decreased. Keywords: tree height growth, nitrogen input, humid-arid climatic transect Acknowledgements: Research is supported by the ÚNKP-16-3-3 New National Excellence Program of the Ministry of Human Capacities and the "Agroclimate.2" (VKSZ_12-1-2013-0034) EU-national joint funded projects.

Unruh effect for mixing neutrinos

NASA Astrophysics Data System (ADS)

Cozzella, Gabriel; Fulling, Stephen A.; Landulfo, André G. S.; Matsas, George E. A.; Vanzella, Daniel A. T.

2018-05-01

Recently, the inverse β -decay rate calculated with respect to uniformly accelerated observers (experiencing the Unruh thermal bath) was revisited. Concerns have been raised regarding the compatibility of inertial and accelerated observers' results when neutrino mixing is taken into account. Here, we show that these concerns are unfounded by discussing the properties of the Unruh thermal bath with mixing neutrinos and explicitly calculating the decay rates according to both sets of observers, confirming thus that they are in agreement. The Unruh effect is perfectly valid for mixing neutrinos.

An absence of neutrinos associated with cosmic-ray acceleration in γ-ray bursts

NASA Astrophysics Data System (ADS)

Abbasi, R.; Abdou, Y.; Abu-Zayyad, T.; Ackermann, M.; Adams, J.; Aguilar, J. A.; Ahlers, M.; Altmann, D.; Andeen, K.; Auffenberg, J.; Bai, X.; Baker, M.; Barwick, S. W.; Bay, R.; Bazo Alba, J. L.; Beattie, K.; Beatty, J. J.; Bechet, S.; Becker, J. K.; Becker, K.-H.; Bell, M.; Benabderrahmane, M. L.; Benzvi, S.; Berdermann, J.; Berghaus, P.; Berley, D.; Bernardini, E.; Bertrand, D.; Besson, D. Z.; Bindig, D.; Bissok, M.; Blaufuss, E.; Blumenthal, J.; Boersma, D. J.; Bohm, C.; Bose, D.; Böser, S.; Botner, O.; Brayeur, L.; Brown, A. M.; Buitink, S.; Caballero-Mora, K. S.; Carson, M.; Casier, M.; Chirkin, D.; Christy, B.; Clevermann, F.; Cohen, S.; Colnard, C.; Cowen, D. F.; Cruz Silva, A. H.; D'Agostino, M. V.; Danninger, M.; Daughhetee, J.; Davis, J. C.; de Clercq, C.; Degner, T.; Descamps, F.; Desiati, P.; de Vries-Uiterweerd, G.; Deyoung, T.; Díaz-Vélez, J. C.; Dierckxsens, M.; Dreyer, J.; Dumm, J. P.; Dunkman, M.; Eisch, J.; Ellsworth, R. W.; Engdegård, O.; Euler, S.; Evenson, P. A.; Fadiran, O.; Fazely, A. R.; Fedynitch, A.; Feintzeig, J.; Feusels, T.; Filimonov, K.; Finley, C.; Fischer-Wasels, T.; Flis, S.; Franckowiak, A.; Franke, R.; Gaisser, T. K.; Gallagher, J.; Gerhardt, L.; Gladstone, L.; Glüsenkamp, T.; Goldschmidt, A.; Goodman, J. A.; Góra, D.; Grant, D.; Griesel, T.; Groß, A.; Grullon, S.; Gurtner, M.; Ha, C.; Haj Ismail, A.; Hallgren, A.; Halzen, F.; Han, K.; Hanson, K.; Heereman, D.; Heinen, D.; Helbing, K.; Hellauer, R.; Hickford, S.; Hill, G. C.; Hoffman, K. D.; Hoffmann, B.; Homeier, A.; Hoshina, K.; Huelsnitz, W.; Hülβ, J.-P.; Hulth, P. O.; Hultqvist, K.; Hussain, S.; Ishihara, A.; Jacobi, E.; Jacobsen, J.; Japaridze, G. S.; Johansson, H.; Kappes, A.; Karg, T.; Karle, A.; Kiryluk, J.; Kislat, F.; Klein, S. R.; Köhne, J.-H.; Kohnen, G.; Kolanoski, H.; Köpke, L.; Kopper, S.; Koskinen, D. J.; Kowalski, M.; Kowarik, T.; Krasberg, M.; Kroll, G.; Kunnen, J.; Kurahashi, N.; Kuwabara, T.; Labare, M.; Laihem, K.; Landsman, H.; Larson, M. J.; Lauer, R.; Lünemann, J.; Madsen, J.; Marotta, A.; Maruyama, R.; Mase, K.; Matis, H. S.; Meagher, K.; Merck, M.; Mészáros, P.; Meures, T.; Miarecki, S.; Middell, E.; Milke, N.; Miller, J.; Montaruli, T.; Morse, R.; Movit, S. M.; Nahnhauer, R.; Nam, J. W.; Naumann, U.; Nowicki, S. C.; Nygren, D. R.; Odrowski, S.; Olivas, A.; Olivo, M.; O'Murchadha, A.; Panknin, S.; Paul, L.; Pérez de Los Heros, C.; Piegsa, A.; Pieloth, D.; Posselt, J.; Price, P. B.; Przybylski, G. T.; Rawlins, K.; Redl, P.; Resconi, E.; Rhode, W.; Ribordy, M.; Richman, M.; Riedel, B.; Rizzo, A.; Rodrigues, J. P.; Rothmaier, F.; Rott, C.; Ruhe, T.; Rutledge, D.; Ruzybayev, B.; Ryckbosch, D.; Sander, H.-G.; Santander, M.; Sarkar, S.; Schatto, K.; Schmidt, T.; Schöneberg, S.; Schönwald, A.; Schukraft, A.; Schulte, L.; Schultes, A.; Schulz, O.; Schunck, M.; Seckel, D.; Semburg, B.; Seo, S. H.; Sestayo, Y.; Seunarine, S.; Silvestri, A.; Smith, M. W. E.; Spiczak, G. M.; Spiering, C.; Stamatikos, M.; Stanev, T.; Stezelberger, T.; Stokstad, R. G.; Stößl, A.; Strahler, E. A.; Ström, R.; Stüer, M.; Sullivan, G. W.; Taavola, H.; Taboada, I.; Tamburro, A.; Ter-Antonyan, S.; Tilav, S.; Toale, P. A.; Toscano, S.; Tosi, D.; van Eijndhoven, N.; van Overloop, A.; van Santen, J.; Vehring, M.; Voge, M.; Walck, C.; Waldenmaier, T.; Wallraff, M.; Walter, M.; Wasserman, R.; Weaver, Ch.; Wendt, C.; Westerhoff, S.; Whitehorn, N.; Wiebe, K.; Wiebusch, C. H.; Williams, D. R.; Wischnewski, R.; Wissing, H.; Wolf, M.; Wood, T. R.; Woschnagg, K.; Xu, C.; Xu, D. L.; Xu, X. W.; Yanez, J. P.; Yodh, G.; Yoshida, S.; Zarzhitsky, P.; Zoll, M.; IceCube Collaboration

2012-04-01

Very energetic astrophysical events are required to accelerate cosmic rays to above 1018electronvolts. GRBs (γ-ray bursts) have been proposed as possible candidate sources. In the GRB `fireball' model, cosmic-ray acceleration should be accompanied by neutrinos produced in the decay of charged pions created in interactions between the high-energy cosmic-ray protons and γ-rays. Previous searches for such neutrinos found none, but the constraints were weak because the sensitivity was at best approximately equal to the predicted flux. Here we report an upper limit on the flux of energetic neutrinos associated with GRBs that is at least a factor of 3.7 below the predictions. This implies either that GRBs are not the only sources of cosmic rays with energies exceeding 1018electronvolts or that the efficiency of neutrino production is much lower than has been predicted.

FERMILAB ACCELERATOR R&D PROGRAM TOWARDS INTENSITY FRONTIER ACCELERATORS : STATUS AND PROGRESS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shiltsev, Vladimir

2016-11-15

The 2014 P5 report indicated the accelerator-based neutrino and rare decay physics research as a centrepiece of the US domestic HEP program at Fermilab. Operation, upgrade and development of the accelerators for the near- term and longer-term particle physics program at the Intensity Frontier face formidable challenges. Here we discuss key elements of the accelerator physics and technology R&D program toward future multi-MW proton accelerators and present its status and progress. INTENSITY FRONTIER ACCELERATORS

Suppressed Charmed B Decay

DOE Office of Scientific and Technical Information (OSTI.GOV)

Snoek, Hella Leonie

2009-06-02

This thesis describes the measurement of the branching fractions of the suppressed charmed B 0 → D *- a 0 + decays and the non-resonant B 0 → D *- ηπ + decays in approximately 230 million Υ(4S) → Bmore » $$\\bar{B}$$ events. The data have been collected with the BABAR detector at the PEP-II B factory at the Stanford Linear Accelerator Center in California. Theoretical predictions of the branching fraction of the B 0 → D *- a{sub 0} + decays show large QCD model dependent uncertainties. Non-factorizing terms, in the naive factorization model, that can be calculated by QCD factorizing models have a large impact on the branching fraction of these decay modes. The predictions of the branching fractions are of the order of 10 -6. The measurement of the branching fraction gives more insight into the theoretical models. In general a better understanding of QCD models will be necessary to conduct weak interaction physics at the next level. The presence of CP violation in electroweak interactions allows the differentiation between matter and antimatter in the laws of physics. In the Standard Model, CP violation is incorporated in the CKM matrix that describes the weak interaction between quarks. Relations amongst the CKM matrix elements are used to present the two relevant parameters as the apex of a triangle (Unitarity Triangle) in a complex plane. The over-constraining of the CKM triangle by experimental measurements is an important test of the Standard Model. At this moment no stringent direct measurements of the CKM angle γ, one of the interior angles of the Unitarity Triangle, are available. The measurement of the angle γ can be performed using the decays of neutral B mesons. The B 0 → D *- a 0 + decay is sensitive to the angle γ and, in comparison to the current decays that are being employed, could significantly enhance the measurement of this angle. However, the low expected branching fraction for the B 0 → D *- a 0 + decay channels could severely impact the measurement. A prerequisite of the measurement of the CKM angle is the observation of the B 0 → D *- a 0 + decay on which this thesis reports. The BABAR experiment consists of the BABAR detector and the PEP-II e +e - collider. The design of the experiment has been optimized for the study of CP violation in the decays of neutral B mesons but is also highly suitable for the search for rare B decays such as the B0 → D *- a 0 + decay. The PEP-II collider operates at the Υ(4S) resonance and is a clean source of B$$\\bar{B}$$ meson pairs.« less

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shiltsev, Vladimir

The 2014 P5 report indicated the accelerator-based neutrino and rare decay physics research as a centerpiece of the US domestic HEP program. Operation, upgrade and development of the accelerators for the near-term and longer-term particle physics program at the Intensity Frontier face formidable challenges. Here we discuss key elements of the accelerator physics and technology R&D program toward future multi-MW proton accelerators.

The impact of sea-level rise on organic matter decay rates in Chesapeake Bay brackish tidal marshes

USGS Publications Warehouse

Kirwanm, M.L.; Langley, J.A.; Guntenspergen, Gleen R.; Megonigal, J.P.

2013-01-01

The balance between organic matter production and decay determines how fast coastal wetlands accumulate soil organic matter. Despite the importance of soil organic matter accumulation rates in influencing marsh elevation and resistance to sea-level rise, relatively little is known about how decomposition rates will respond to sea-level rise. Here, we estimate the sensitivity of decomposition to flooding by measuring rates of decay in 87 bags filled with milled sedge peat, including soil organic matter, roots and rhizomes. Experiments were located in field-based mesocosms along 3 mesohaline tributaries of the Chesapeake Bay. Mesocosm elevations were manipulated to influence the duration of tidal inundation. Although we found no significant influence of inundation on decay rate when bags from all study sites were analyzed together, decay rates at two of the sites increased with greater flooding. These findings suggest that flooding may enhance organic matter decay rates even in water-logged soils, but that the overall influence of flooding is minor. Our experiments suggest that sea-level rise will not accelerate rates of peat accumulation by slowing the rate of soil organic matter decay. Consequently, marshes will require enhanced organic matter productivity or mineral sediment deposition to survive accelerating sea-level rise.

The impact of sea-level rise on organic matter decay rates in Chesapeake Bay brackish tidal marshes

NASA Astrophysics Data System (ADS)

Kirwan, M. L.; Langley, J. A.; Guntenspergen, G. R.; Megonigal, J. P.

2013-03-01

The balance between organic matter production and decay determines how fast coastal wetlands accumulate soil organic matter. Despite the importance of soil organic matter accumulation rates in influencing marsh elevation and resistance to sea-level rise, relatively little is known about how decomposition rates will respond to sea-level rise. Here, we estimate the sensitivity of decomposition to flooding by measuring rates of decay in 87 bags filled with milled sedge peat, including soil organic matter, roots and rhizomes. Experiments were located in field-based mesocosms along 3 mesohaline tributaries of the Chesapeake Bay. Mesocosm elevations were manipulated to influence the duration of tidal inundation. Although we found no significant influence of inundation on decay rate when bags from all study sites were analyzed together, decay rates at two of the sites increased with greater flooding. These findings suggest that flooding may enhance organic matter decay rates even in water-logged soils, but that the overall influence of flooding is minor. Our experiments suggest that sea-level rise will not accelerate rates of peat accumulation by slowing the rate of soil organic matter decay. Consequently, marshes will require enhanced organic matter productivity or mineral sediment deposition to survive accelerating sea-level rise.

The impact of sea-level rise on organic matter decay rates in Chesapeake Bay brackish tidal marshes

NASA Astrophysics Data System (ADS)

Kirwan, M. L.; Langley, J. A.; Guntenspergen, G. R.; Megonigal, J. P.

2012-10-01

The balance between organic matter production and decay determines how fast coastal wetlands accumulate soil organic matter. Despite the importance of soil organic matter accumulation rates in influencing marsh elevation and resistance to sea-level rise, relatively little is known about how decomposition rates will respond to sea-level rise. Here, we estimate the sensitivity of decomposition to flooding by measuring rates of decay in 87 bags filled with milled sedge peat, including soil organic matter, roots and rhizomes. Experiments were located in field-based mesocosms along 3 mesohaline tributaries of the Chesapeake Bay. Mesocosm elevations were manipulated to influence the duration of tidal inundation. Although we found no significant influence of inundation on decay rate when bags from all study sites were analyzed together, decay rates at two of the sites increased with greater flooding. These findings suggest that flooding may enhance organic matter decay rates even in water-logged soils, but that the overall influence of flooding is minor. Our experiments suggest that sea-level rise will not accelerate rates of peat accumulation by slowing the rate of soil organic matter decay. Consequently, marshes will require enhanced organic matter productivity or mineral sediment deposition to survive accelerating sea-level rise.

Compressed sensing for high-resolution nonlipid suppressed 1 H FID MRSI of the human brain at 9.4T.

PubMed

Nassirpour, Sahar; Chang, Paul; Avdievitch, Nikolai; Henning, Anke

2018-04-29

The aim of this study was to apply compressed sensing to accelerate the acquisition of high resolution metabolite maps of the human brain using a nonlipid suppressed ultra-short TR and TE 1 H FID MRSI sequence at 9.4T. X-t sparse compressed sensing reconstruction was optimized for nonlipid suppressed 1 H FID MRSI data. Coil-by-coil x-t sparse reconstruction was compared with SENSE x-t sparse and low rank reconstruction. The effect of matrix size and spatial resolution on the achievable acceleration factor was studied. Finally, in vivo metabolite maps with different acceleration factors of 2, 4, 5, and 10 were acquired and compared. Coil-by-coil x-t sparse compressed sensing reconstruction was not able to reliably recover the nonlipid suppressed data, rather a combination of parallel and sparse reconstruction was necessary (SENSE x-t sparse). For acceleration factors of up to 5, both the low-rank and the compressed sensing methods were able to reconstruct the data comparably well (root mean squared errors [RMSEs] ≤ 10.5% for Cre). However, the reconstruction time of the low rank algorithm was drastically longer than compressed sensing. Using the optimized compressed sensing reconstruction, acceleration factors of 4 or 5 could be reached for the MRSI data with a matrix size of 64 × 64. For lower spatial resolutions, an acceleration factor of up to R∼4 was successfully achieved. By tailoring the reconstruction scheme to the nonlipid suppressed data through parameter optimization and performance evaluation, we present high resolution (97 µL voxel size) accelerated in vivo metabolite maps of the human brain acquired at 9.4T within scan times of 3 to 3.75 min. © 2018 International Society for Magnetic Resonance in Medicine.

Extrinsic and Intrinsic Brain Network Connectivity Maintains Cognition across the Lifespan Despite Accelerated Decay of Regional Brain Activation.

PubMed

Tsvetanov, Kamen A; Henson, Richard N A; Tyler, Lorraine K; Razi, Adeel; Geerligs, Linda; Ham, Timothy E; Rowe, James B

2016-03-16

The maintenance of wellbeing across the lifespan depends on the preservation of cognitive function. We propose that successful cognitive aging is determined by interactions both within and between large-scale functional brain networks. Such connectivity can be estimated from task-free functional magnetic resonance imaging (fMRI), also known as resting-state fMRI (rs-fMRI). However, common correlational methods are confounded by age-related changes in the neurovascular signaling. To estimate network interactions at the neuronal rather than vascular level, we used generative models that specified both the neural interactions and a flexible neurovascular forward model. The networks' parameters were optimized to explain the spectral dynamics of rs-fMRI data in 602 healthy human adults from population-based cohorts who were approximately uniformly distributed between 18 and 88 years (www.cam-can.com). We assessed directed connectivity within and between three key large-scale networks: the salience network, dorsal attention network, and default mode network. We found that age influences connectivity both within and between these networks, over and above the effects on neurovascular coupling. Canonical correlation analysis revealed that the relationship between network connectivity and cognitive function was age-dependent: cognitive performance relied on neural dynamics more strongly in older adults. These effects were driven partly by reduced stability of neural activity within all networks, as expressed by an accelerated decay of neural information. Our findings suggest that the balance of excitatory connectivity between networks, and the stability of intrinsic neural representations within networks, changes with age. The cognitive function of older adults becomes increasingly dependent on these factors. Maintaining cognitive function is critical to successful aging. To study the neural basis of cognitive function across the lifespan, we studied a large population-based cohort (n = 602, 18-88 years), separating neural connectivity from vascular components of fMRI signals. Cognitive ability was influenced by the strength of connection within and between functional brain networks, and this positive relationship increased with age. In older adults, there was more rapid decay of intrinsic neuronal activity in multiple regions of the brain networks, which related to cognitive performance. Our data demonstrate increased reliance on network flexibility to maintain cognitive function, in the presence of more rapid decay of neural activity. These insights will facilitate the development of new strategies to maintain cognitive ability. Copyright © 2016 Tsvetanov et al.

Extrinsic and Intrinsic Brain Network Connectivity Maintains Cognition across the Lifespan Despite Accelerated Decay of Regional Brain Activation

PubMed Central

Henson, Richard N.A.; Tyler, Lorraine K.; Razi, Adeel; Geerligs, Linda; Ham, Timothy E.; Rowe, James B.

2016-01-01

The maintenance of wellbeing across the lifespan depends on the preservation of cognitive function. We propose that successful cognitive aging is determined by interactions both within and between large-scale functional brain networks. Such connectivity can be estimated from task-free functional magnetic resonance imaging (fMRI), also known as resting-state fMRI (rs-fMRI). However, common correlational methods are confounded by age-related changes in the neurovascular signaling. To estimate network interactions at the neuronal rather than vascular level, we used generative models that specified both the neural interactions and a flexible neurovascular forward model. The networks' parameters were optimized to explain the spectral dynamics of rs-fMRI data in 602 healthy human adults from population-based cohorts who were approximately uniformly distributed between 18 and 88 years (www.cam-can.com). We assessed directed connectivity within and between three key large-scale networks: the salience network, dorsal attention network, and default mode network. We found that age influences connectivity both within and between these networks, over and above the effects on neurovascular coupling. Canonical correlation analysis revealed that the relationship between network connectivity and cognitive function was age-dependent: cognitive performance relied on neural dynamics more strongly in older adults. These effects were driven partly by reduced stability of neural activity within all networks, as expressed by an accelerated decay of neural information. Our findings suggest that the balance of excitatory connectivity between networks, and the stability of intrinsic neural representations within networks, changes with age. The cognitive function of older adults becomes increasingly dependent on these factors. SIGNIFICANCE STATEMENT Maintaining cognitive function is critical to successful aging. To study the neural basis of cognitive function across the lifespan, we studied a large population-based cohort (n = 602, 18–88 years), separating neural connectivity from vascular components of fMRI signals. Cognitive ability was influenced by the strength of connection within and between functional brain networks, and this positive relationship increased with age. In older adults, there was more rapid decay of intrinsic neuronal activity in multiple regions of the brain networks, which related to cognitive performance. Our data demonstrate increased reliance on network flexibility to maintain cognitive function, in the presence of more rapid decay of neural activity. These insights will facilitate the development of new strategies to maintain cognitive ability. PMID:26985024

Is Deuterium Nuclear Fusion Catalyzed by Antineutrinos?

NASA Astrophysics Data System (ADS)

Shomer, Isaac

2010-02-01

The hypothesis of Fischbach and Jenkins that neutrinos emitted from the sun accelerate radioactive decay is noted. It is thought that neutrinos accelerate beta decay by reacting with neutron-rich nuclides to form a beta particle and a daughter product, with no antineutrino emitted. Conversely, it is proposed that antineutrinos can react with proton-rich nuclides to cause positron decay, with no neutrino emitted. It is also proposed that the nuclear fusion of the hydrogen bomb is triggered not only by the energy of the igniting fission bomb, but by the antineutrinos created by the rapid beta decay of the daughter products in the fission process. The contemplated mechanism for antineutrino initiated fusion is the following: 1. The antineutrinos from the fission daughter products cause positron decay of deuterium by the process outlined above. 2. In a later fusion step, these positrons subsequently react with neutrons in deuterium to create antineutrinos. Electrons are unavailable to annihilate positrons in the plasma of the hydrogen bomb. 3. These antineutrinos thereafter react with more deuterium to form positrons, thereby propagating a chain reaction. )

Soil attributes and microclimate are important drivers of initial deadwood decay in sub-alpine Norway spruce forests.

PubMed

Fravolini, Giulia; Egli, Markus; Derungs, Curdin; Cherubini, Paolo; Ascher-Jenull, Judith; Gómez-Brandón, María; Bardelli, Tommaso; Tognetti, Roberto; Lombardi, Fabio; Marchetti, Marco

2016-11-01

Deadwood is known to significantly contribute to global terrestrial carbon stocks and carbon cycling, but its decay dynamics are still not thoroughly understood. Although the chemistry of deadwood has been studied as a function of decay stage in temperate to subalpine environments, it has generally not been related to time. We therefore studied the decay (mass of deadwood, cellulose and lignin) of equal-sized blocks of Picea abies wood in soil-mesocosms over two years in the Italian Alps. The 8 sites selected were along an altitudinal sequence, reflecting different climate zones. In addition, the effect of exposure (north- and south-facing slopes) was taken into account. The decay dynamics of the mass of deadwood, cellulose and lignin were related to soil parameters (pH, soil texture, moisture, temperature) and climatic data. The decay rate constants of Picea abies deadwood were low (on average between 0.039 and 0.040y(-1)) and of lignin close to zero (or not detectable), while cellulose reacted much faster with average decay rate constants between 0.110 and 0.117y(-1). Our field experiments showed that local scale factors, such as soil parameters and topographic properties, influenced the decay process: higher soil moisture and clay content along with a lower pH seemed to accelerate wood decay. Interestingly, air temperature negatively correlated with decay rates or positively with the amount of wood components on south-facing sites. It exerted its influence rather on moisture availability, i.e. the lower the temperature the higher the moisture availability. Topographic features were also relevant with generally slower decay processes on south-facing sites than on north-facing sites owing to the drier conditions, the higher pH and the lower weathering state of the soils (less clay minerals). This study highlights the importance of a multifactorial consideration of edaphic parameters to unravel the complex dynamics of initial wood decay. Copyright © 2016 Elsevier B.V. All rights reserved.

Superallowed Fermi β decay studies at TRIUMF-ISAC

NASA Astrophysics Data System (ADS)

Svensson, C. E.; Dunlop, R.; Finlay, P.; Ball, G. C.; Ettenauer, S.; Leslie, J. R.; Towner, I. S.; Andreoiu, C.; Austin, R. A. E.; Bandyopadhyay, D.; Chagnon-Lessard, S.; Chester, A.; Cross, D. S.; Demand, G.; Djongolov, M.; Garnsworthy, A. B.; Garrett, P. E.; Green, K. L.; Glister, J.; Grinyer, G. F.; Hackman, G.; Hadinia, B.; Leach, K. G.; Pearson, C. J.; Phillips, A. A.; Rand, E. T.; Starosta, K.; Sumithrarachchi, C. S.; Tardiff, E. R.; Triambak, S.; Williams, S. J.; Wong, J.; Yates, S. W.; Zganjar, E. F.

2013-10-01

A program of high-precision superallowed Fermi β decay studies is being carried out at the Isotope Separator and Accelerator (ISAC) radioactive ion beam facility at TRIUMF. Recent high-precision branching ratio measurements for the superallowed decays of 74Rb and 26Alm, as well as a half-life measurement for 26Alm that is the most precise half-life measurement for any superallowed emitter to date, are reported. These results provide demanding tests of the theoretical isospin symmetry breaking corrections in superallowed Fermi β decays.

Visualizing spatial population structure with estimated effective migration surfaces

PubMed Central

Petkova, Desislava; Novembre, John; Stephens, Matthew

2015-01-01

Genetic data often exhibit patterns broadly consistent with “isolation by distance” – a phenomenon where genetic similarity decays with geographic distance. In a heterogeneous habitat this may occur more quickly in some regions than others: for example, barriers to gene flow can accelerate differentiation between neighboring groups. We use the concept of “effective migration” to model the relationship between genetics and geography: in this paradigm, effective migration is low in regions where genetic similarity decays quickly. We present a method to visualize variation in effective migration across the habitat from geographically indexed genetic data. Our approach uses a population genetic model to relate effective migration rates to expected genetic dissimilarities. We illustrate its potential and limitations using simulations and data from elephant, human and A. thaliana populations. The resulting visualizations highlight important spatial features of population structure that are difficult to discern using existing methods for summarizing genetic variation. PMID:26642242

Role of neutrino mixing in accelerated proton decay

NASA Astrophysics Data System (ADS)

Blasone, M.; Lambiase, G.; Luciano, G. G.; Petruzziello, L.

2018-05-01

The decay of accelerated protons has been analyzed both in the laboratory frame (where the proton is accelerated) and in the comoving frame (where the proton is at rest and interacts with the Fulling-Davies-Unruh thermal bath of electrons and neutrinos). The equality between the two rates has been exhibited as an evidence of the necessity of Fulling-Davies-Unruh effect for the consistency of quantum field theory formalism. Recently, it has been argued that neutrino mixing can spoil such a result, potentially opening new scenarios in neutrino physics. In the present paper, we analyze in detail this problem, and we find that, assuming flavor neutrinos to be fundamental and working within a certain approximation, the agreement can be restored.

Neutrino flux from cosmic ray accelerators in the Cygnus spiral arm of the Galaxy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Anchordoqui, Luis; Halzen, Francis; O'Murchadha, Aongus

2007-09-15

Intriguing evidence has been accumulating for the production of cosmic rays in the Cygnus region of the galactic plane. We here show that the IceCube experiment can produce incontrovertible evidence for cosmic ray acceleration by observing the neutrinos from the decay of charged pions accompanying the TeV photon flux observed in the HEGRA, Whipple, Tibet, and Milagro experiments. Our assumption is that the TeV photons observed are the decay products of neutral pions produced by cosmic ray accelerators in the nearby spiral arm of the galaxy. Because of the proximity of the sources, IceCube will obtain evidence at the 5{sigma}more » level in 15 years of observation.« less

Site-Dependent Fluorescence Decay of Malachite Green Doped in Onion Cell

NASA Astrophysics Data System (ADS)

Nakatsuka, Hiroki; Sekine, Masaya; Suzuki, Yuji; Hattori, Toshiaki

1999-03-01

Time-resolved fluorescence measurements of malachite green dye moleculesdoped in onion cells were carried out.The fluorescence decay time was dependent on the individual cell and on theposition of the dye in a cell, which reflect the microscopic dynamics of each boundsite.Upon cooling, the decay time increased and this increase was accelerated ataround the freezing point of the onion cell.

Dynamics of Mesoscale Magnetic Field in Diffusive Shock Acceleration

NASA Astrophysics Data System (ADS)

Diamond, P. H.; Malkov, M. A.

2007-01-01

We present a theory for the generation of mesoscale (krg<<1, where rg is the cosmic-ray gyroradius) magnetic fields during diffusive shock acceleration. The decay or modulational instability of resonantly excited Alfvén waves scattering off ambient density perturbations in the shock environment naturally generates larger scale fields. For a broad spectrum of perturbations, the physical mechanism of energy transfer is random refraction, represented by the diffusion of Alfvén wave packets in k-space. The scattering field can be produced directly by the decay instability or by the Drury instability, a hydrodynamic instability driven by the cosmic-ray pressure gradient. This process is of interest to acceleration since it generates waves of longer wavelength, and so enables the confinement and acceleration of higher energy particles. This process also limits the intensity of resonantly generated turbulent magnetic fields on rg scales.

Geographically Modified PageRank Algorithms: Identifying the Spatial Concentration of Human Movement in a Geospatial Network.

PubMed

Chin, Wei-Chien-Benny; Wen, Tzai-Hung

2015-01-01

A network approach, which simplifies geographic settings as a form of nodes and links, emphasizes the connectivity and relationships of spatial features. Topological networks of spatial features are used to explore geographical connectivity and structures. The PageRank algorithm, a network metric, is often used to help identify important locations where people or automobiles concentrate in the geographical literature. However, geographic considerations, including proximity and location attractiveness, are ignored in most network metrics. The objective of the present study is to propose two geographically modified PageRank algorithms-Distance-Decay PageRank (DDPR) and Geographical PageRank (GPR)-that incorporate geographic considerations into PageRank algorithms to identify the spatial concentration of human movement in a geospatial network. Our findings indicate that in both intercity and within-city settings the proposed algorithms more effectively capture the spatial locations where people reside than traditional commonly-used network metrics. In comparing location attractiveness and distance decay, we conclude that the concentration of human movement is largely determined by the distance decay. This implies that geographic proximity remains a key factor in human mobility.

Man-systems evaluation of moving base vehicle simulation motion cues. [human acceleration perception involving visual feedback

NASA Technical Reports Server (NTRS)

Kirkpatrick, M.; Brye, R. G.

1974-01-01

A motion cue investigation program is reported that deals with human factor aspects of high fidelity vehicle simulation. General data on non-visual motion thresholds and specific threshold values are established for use as washout parameters in vehicle simulation. A general purpose similator is used to test the contradictory cue hypothesis that acceleration sensitivity is reduced during a vehicle control task involving visual feedback. The simulator provides varying acceleration levels. The method of forced choice is based on the theory of signal detect ability.

Mass spectrometric identification of proteins that interact through specific domains of the poly(A) binding protein

PubMed Central

Zhang, Chongxu; Nielsen, Maria E. O.; Chiang, Yueh-Chin; Kierkegaard, Morten; Wang, Xin; Lee, Darren J.; Andersen, Jens S.; Yao, Gang

2013-01-01

Poly(A) binding protein (PAB1) is involved in a number of RNA metabolic functions in eukaryotic cells and correspondingly is suggested to associate with a number of proteins. We have used mass spectrometric analysis to identify 55 non-ribosomal proteins that specifically interact with PAB1 from Saccharomyces cerevisiae. Because many of these factors may associate only indirectly with PAB1 by being components of the PAB1-mRNP structure, we additionally conducted mass spectrometric analyses on seven metabolically defined PAB1 deletion derivatives to delimit the interactions between these proteins and PAB1. These latter analyses identified 13 proteins whose associations with PAB1 were reduced by deleting one or another of PAB1’s defined domains. Included in this list of 13 proteins were the translation initiation factors eIF4G1 and eIF4G2, translation termination factor eRF3, and PBP2, all of whose previously known direct interactions with specific PAB1 domains were either confirmed, delimited, or extended. The remaining nine proteins that interacted through a specific PAB1 domain were CBF5, SLF1, UPF1, CBC1, SSD1, NOP77, yGR250c, NAB6, and GBP2. In further study, UPF1, involved in nonsense-mediated decay, was confirmed to interact with PAB1 through the RRM1 domain. We additionally established that while the RRM1 domain of PAB1 was required for UPF1-induced acceleration of deadenylation during nonsense-mediated decay, it was not required for the more critical step of acceleration of mRNA decapping. These results begin to identify the proteins most likely to interact with PAB1 and the domains of PAB1 through which these contacts are made. PMID:22836166

Mass spectrometric identification of proteins that interact through specific domains of the poly(A) binding protein.

PubMed

Richardson, Roy; Denis, Clyde L; Zhang, Chongxu; Nielsen, Maria E O; Chiang, Yueh-Chin; Kierkegaard, Morten; Wang, Xin; Lee, Darren J; Andersen, Jens S; Yao, Gang

2012-09-01

Poly(A) binding protein (PAB1) is involved in a number of RNA metabolic functions in eukaryotic cells and correspondingly is suggested to associate with a number of proteins. We have used mass spectrometric analysis to identify 55 non-ribosomal proteins that specifically interact with PAB1 from Saccharomyces cerevisiae. Because many of these factors may associate only indirectly with PAB1 by being components of the PAB1-mRNP structure, we additionally conducted mass spectrometric analyses on seven metabolically defined PAB1 deletion derivatives to delimit the interactions between these proteins and PAB1. These latter analyses identified 13 proteins whose associations with PAB1 were reduced by deleting one or another of PAB1's defined domains. Included in this list of 13 proteins were the translation initiation factors eIF4G1 and eIF4G2, translation termination factor eRF3, and PBP2, all of whose previously known direct interactions with specific PAB1 domains were either confirmed, delimited, or extended. The remaining nine proteins that interacted through a specific PAB1 domain were CBF5, SLF1, UPF1, CBC1, SSD1, NOP77, yGR250c, NAB6, and GBP2. In further study, UPF1, involved in nonsense-mediated decay, was confirmed to interact with PAB1 through the RRM1 domain. We additionally established that while the RRM1 domain of PAB1 was required for UPF1-induced acceleration of deadenylation during nonsense-mediated decay, it was not required for the more critical step of acceleration of mRNA decapping. These results begin to identify the proteins most likely to interact with PAB1 and the domains of PAB1 through which these contacts are made.

Evaluation of five microbial and four mitochondrial DNA markers for tracking human and pig fecal pollution in freshwater

PubMed Central

He, Xiwei; Liu, Peng; Zheng, Guolu; Chen, Huimei; Shi, Wei; Cui, Yibin; Ren, Hongqiang; Zhang, Xu-Xiang

2016-01-01

This study systematically evaluated five microbial and four mitochondrial DNA (mtDNA) markers, including sensitivities and specificities under PCR method, and fecal concentrations and decay rates in water under qPCR method. The microbial DNA markers were the three human-associated (BacH, HF183 and B.adolescentis) and two pig-associated (Pig-2-Bac and L.amylovorus), while the mtDNA ones were two human- (H-ND6 and H-ND5) and two pig-associated (P-CytB and P-ND5). All the mtDNA markers showed higher sensitivity (100%) than the microbial ones (84.0–88.8%) except Pig-2-Bac (100%). Specificities of the human mtDNA markers (99.1 and 98.1%) were higher than those of the human-associated microbial ones (57.0–88.8%). But this pattern was not observed in the pig-associated markers where Pig-2-Bac had 100% specificity. The reliability of H-ND6 and H-ND5 was further evidenced to identify locations of the most polluted within the Taihu Lake watershed of China. In general, the microbial DNA markers demonstrated a higher fecal concentration than the mtDNA ones; increasing temperature and sunlight exposure accelerated significantly the decay of all the DNA markers. Results of this study suggest that DNA markers H-ND6, H-ND5, and Pig-2-Bac may be among the best for fecal source tracking in water. PMID:27734941

Evaluation of five microbial and four mitochondrial DNA markers for tracking human and pig fecal pollution in freshwater

NASA Astrophysics Data System (ADS)

He, Xiwei; Liu, Peng; Zheng, Guolu; Chen, Huimei; Shi, Wei; Cui, Yibin; Ren, Hongqiang; Zhang, Xu-Xiang

2016-10-01

This study systematically evaluated five microbial and four mitochondrial DNA (mtDNA) markers, including sensitivities and specificities under PCR method, and fecal concentrations and decay rates in water under qPCR method. The microbial DNA markers were the three human-associated (BacH, HF183 and B.adolescentis) and two pig-associated (Pig-2-Bac and L.amylovorus), while the mtDNA ones were two human- (H-ND6 and H-ND5) and two pig-associated (P-CytB and P-ND5). All the mtDNA markers showed higher sensitivity (100%) than the microbial ones (84.0-88.8%) except Pig-2-Bac (100%). Specificities of the human mtDNA markers (99.1 and 98.1%) were higher than those of the human-associated microbial ones (57.0-88.8%). But this pattern was not observed in the pig-associated markers where Pig-2-Bac had 100% specificity. The reliability of H-ND6 and H-ND5 was further evidenced to identify locations of the most polluted within the Taihu Lake watershed of China. In general, the microbial DNA markers demonstrated a higher fecal concentration than the mtDNA ones; increasing temperature and sunlight exposure accelerated significantly the decay of all the DNA markers. Results of this study suggest that DNA markers H-ND6, H-ND5, and Pig-2-Bac may be among the best for fecal source tracking in water.

Human Cytomegalovirus Secretome Contains Factors That Induce Angiogenesis and Wound Healing

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dumortier, Jerome; Streblow, Daniel N.; Moses, Ashlee V.

2008-07-01

Human cytomegalovirus (HCMV) is implicated in the acceleration of a number of vascular diseases including transplant vascular sclerosis (TVS), the lesion associated with chronic rejection (CR) of solid organ transplants. Although the virus persists in the allograft throughout the course of disease, few cells are directly infected by CMV. This observation is in contrast to the global effects that CMV has on the acceleration of TVS/CR, suggesting that CMV infection indirectly promotes the vascular disease process. Recent transcriptome analysis of CMV-infected heart allografts indicates that the virus induces cytokines and growth factors associated with angiogenesis (AG) and wound healing (WH),more » suggesting that CMV may accelerate TVS/CR through the induction and secretion of AG/WH factors from infected cells. We analyzed virus-free supernatants from HCMV-infected cells (HCMV secretomes) for growth factors, by mass spectrometry and immunoassays, and found that the HCMV secretome contains over 1,000 cellular proteins, many of which are involved in AG/WH. Importantly, functional assays demonstrated that CMV but not herpes simplex virus secretomes not only induce AG/WH but also promote neovessel stabilization and endothelial cell survival for 2 weeks. These findings suggest that CMV acceleration of TVS occurs through virus-induced growth factors and cytokines in the CMV secretome.« less

Search for CP Violation in Hyperon Decay: $$\\Xi^- / \\bar{\\Xi}^+$$ and $$\\Lambda / \\bar{\\Lambda}$$ (in French)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Leros, Nicolas

2001-06-01

The HyperCP(EB71) experiment, performed at the Fermi National Accelerator Laboratory in the United States, provides a primary search for direct OP violation in the decays ofmore » $$\\Xi^-/\\bar{\\Xi}^+$$ and $$\\Lambda/ \\bar{\\Lambda}$$ hyperons....« less

Radioisotope Dating with Accelerators.

ERIC Educational Resources Information Center

Muller, Richard A.

1979-01-01

Explains a new method of detecting radioactive isotopes by counting their accelerated ions rather than the atoms that decay during the counting period. This method increases the sensitivity by several orders of magnitude, and allows one to find the ages of much older and smaller samples. (GA)

Electron capture decay in Jovian planets

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zito, R.R.; Schiferl, D.

1987-12-01

Following the commonly acknowledged fact that the decay of K-40 substantially contributes to the heating of planetary interiors, an examination is made of the possibility that interior heat in the Jovian planets and stars, where interior pressures may exceed 45 Mbar, may be generated by the pressure-accelerated electron capture decay of a variety of isotopes. The isotopes considered encompass K-40, V-50, Te-123, La-138, Al-26, and Cl-36. 19 references.

Hydrocortisone accelerates the decay of iconic memory traces: on the modulation of executive and stimulus-driven constituents of sensory information maintenance.

PubMed

Miller, Robert; Weckesser, Lisa J; Smolka, Michael N; Kirschbaum, Clemens; Plessow, Franziska

2015-03-01

A substantial amount of research documents the impact of glucocorticoids on higher-order cognitive functioning. By contrast, surprisingly little is known about the susceptibility of basic sensory processes to glucocorticoid exposure given that the glucocorticoid receptor density in the human visual cortex exceeds those observed in prefrontal and most hippocampal brain regions. As executive tasks also rely on these sensory processes, the present study investigates the impact of glucocorticoid exposure on different performance parameters characterizing the maintenance and transfer of sensory information from iconic memory (IM; the sensory buffer of the visual system) to working memory (WM). Using a crossover factorial design, we administered one out of three doses of hydrocortisone (0.06, 0.12, or 0.24mg/kg bodyweight) and a placebo to 18 healthy young men. Thereafter participants performed a partial report task, which was used to assess their individual ability to process sensory information. Blood samples were concurrently drawn to determine free and total cortisol concentrations. The compiled pharmacokinetic and psychophysical data demonstrates that free cortisol specifically accelerated the decay of sensory information (r=0.46) without significantly affecting the selective information transfer from IM to WM or the capacity limit of WM. Specifically, nonparametric regression revealed a sigmoid dose-response relationship between free cortisol levels during the testing period and the IM decay rates. Our findings highlight that glucocorticoid exposure may not only impact on the recruitment of top-down control for an active maintenance of sensory information, but alter their passive (stimulus-driven) maintenance thereby changing the availability of information prior to subsequent executive processing. Copyright © 2014 Elsevier Ltd. All rights reserved.

Spectroscopic Factors from the Single Neutron Pickup ^64Zn(d,t)

NASA Astrophysics Data System (ADS)

Leach, Kyle; Garrett, P. E.; Demand, G. A.; Finlay, P.; Green, K. L.; Phillips, A. A.; Rand, E. T.; Sumithrarachchi, C. S.; Svensson, C. E.; Triambak, S.; Wong, J.; Towner, I. S.; Ball, G. C.; Faestermann, T.; Krücken, R.; Hertenberger, R.; Wirth, H.-F.

2010-11-01

A great deal of attention has recently been paid towards high-precision superallowed β-decay Ft values. With the availability of extremely high-precision (<0.1%) experimental data, precision on the individual Ft values are now dominated by the ˜1% theoretical corrections. This limitation is most evident in heavier superallowed nuclei (e.g. ^62Ga) where the isospin-symmetry-breaking (ISB) correction calculations become more difficult due to the truncated model space. Experimental spectroscopic factors for these nuclei are important for the identification of the relevant orbitals that should be included in the model space of the calculations. Motivated by this need, the single-nucleon transfer reaction ^64Zn(d,t)^63Zn was conducted at the Maier-Leibnitz-Laboratory (MLL) of TUM/LMU in Munich, Germany, using a 22 MeV polarized deuteron beam from the tandem Van de Graaff accelerator and the TUM/LMU Q3D magnetic spectrograph, with angular distributions from 10^o to 60^o. Results from this experiment will be presented and implications for calculations of ISB corrections in the superallowed ° decay of ^62Ga will be discussed.

Rhynchophylline from Uncaria rhynchophylla functionally turns delayed rectifiers into A-Type K+ channels.

PubMed

Chou, Chun-Hsiao; Gong, Chi-Li; Chao, Chia-Chia; Lin, Chia-Huei; Kwan, Chiu-Yin; Hsieh, Ching-Liang; Leung, Yuk-Man

2009-05-22

Rhynchophylline (1), a neuroprotective agent isolated from the traditional Chinese medicinal herb Uncaria rhynchophylla, was shown to affect voltage-gated K(+) (Kv) channel slow inactivation in mouse neuroblastoma N2A cells. Extracellular 1 (30 microM) accelerated the slow decay of Kv currents and shifted the steady-state inactivation curve to the left. Intracellular dialysis of 1 did not accelerate the slow current decay, suggesting that this compound acts extracellularly. In addition, the percent blockage of Kv currents by this substance was independent of the degree of depolarization and the intracellular K(+) concentration. Therefore, 1 did not appear to directly block the outer channel pore, with the results obtained suggesting that it drastically accelerated Kv channel slow inactivation. Interestingly, 1 also shifted the activation curve to the left. This alkaloid also strongly accelerated slow inactivation and caused a left shift of the activation curve of Kv1.2 channels heterologously expressed in HEK293 cells. Thus, this compound functionally turned delayed rectifiers into A-type K(+) channels.

Recent Advances in Catalyst Accelerated Stress Tests for Polymer Electrolyte Membrane Fuel Cells

DOE PAGES

Stariha, Sarah; Macauley, Natalia; Sneed, Brian T.; ...

2018-03-15

The U.S. Department of Energy (DOE) set the 2020 durability target for polymer electrolyte membrane fuel cell transportation applications at 5000 hours. Since it is impractical to test every fuel cell for this length of time, there is ever increasing interest in developing accelerated stress tests (ASTs) that can accurately simulate the material component degradation in the membrane electrode assembly (MEA) observed under automotive operating conditions, but over a much shorter time frame. In this study, a square-wave catalyst AST was examined that shows a 5X time acceleration factor over the triangle-wave catalyst AST and a 25X time acceleration factormore » over the modified wet drive-cycle catalyst durability protocol, significantly decreasing the testing time. These acceleration factors were correlated to the platinum (Pt) particle size increase and associated decrease in electrochemical surface area (ECSA). This square-wave AST has been adopted by the DOE as a standard protocol to evaluate catalyst durability. We also compare three catalyst-durability protocols using state-of-the-art platinum-cobalt catalysts supported on high surface area carbon (SOA Pt-Co/HSAC) in the cathode catalyst layer. The results for each of the three tests showed both catalyst particle size increase and transition metal leaching. Moreover the acceleration factors for the alloy catalysts were smaller due to Co leaching being the predominant mechanism of voltage decay in ~5 nm PtCo/C catalysts. Finally, an extremely harsh carbon corrosion AST was run using the same SOA Pt-Co/HSAC catalyst. This showed minimal change in particle size and a low percentage Co loss from the cathode catalyst particles, despite a significant loss in catalyst layer thickness and cell performance. The carbon corrosion rates during these various ASTs were directly measured by monitoring the CO 2 emission from the cathode, further confirming the ability of the square-wave AST to evaluate the electro-catalyst independently of the support.« less

Recent Advances in Catalyst Accelerated Stress Tests for Polymer Electrolyte Membrane Fuel Cells

DOE Office of Scientific and Technical Information (OSTI.GOV)

Stariha, Sarah; Macauley, Natalia; Sneed, Brian T.

The U.S. Department of Energy (DOE) set the 2020 durability target for polymer electrolyte membrane fuel cell transportation applications at 5000 hours. Since it is impractical to test every fuel cell for this length of time, there is ever increasing interest in developing accelerated stress tests (ASTs) that can accurately simulate the material component degradation in the membrane electrode assembly (MEA) observed under automotive operating conditions, but over a much shorter time frame. In this study, a square-wave catalyst AST was examined that shows a 5X time acceleration factor over the triangle-wave catalyst AST and a 25X time acceleration factormore » over the modified wet drive-cycle catalyst durability protocol, significantly decreasing the testing time. These acceleration factors were correlated to the platinum (Pt) particle size increase and associated decrease in electrochemical surface area (ECSA). This square-wave AST has been adopted by the DOE as a standard protocol to evaluate catalyst durability. We also compare three catalyst-durability protocols using state-of-the-art platinum-cobalt catalysts supported on high surface area carbon (SOA Pt-Co/HSAC) in the cathode catalyst layer. The results for each of the three tests showed both catalyst particle size increase and transition metal leaching. Moreover the acceleration factors for the alloy catalysts were smaller due to Co leaching being the predominant mechanism of voltage decay in ~5 nm PtCo/C catalysts. Finally, an extremely harsh carbon corrosion AST was run using the same SOA Pt-Co/HSAC catalyst. This showed minimal change in particle size and a low percentage Co loss from the cathode catalyst particles, despite a significant loss in catalyst layer thickness and cell performance. The carbon corrosion rates during these various ASTs were directly measured by monitoring the CO 2 emission from the cathode, further confirming the ability of the square-wave AST to evaluate the electro-catalyst independently of the support.« less

CCR4-NOT deadenylates mRNA associated with RNA-induced silencing complexes in human cells.

PubMed

Piao, Xianghua; Zhang, Xue; Wu, Ligang; Belasco, Joel G

2010-03-01

MicroRNAs (miRNAs) repress gene expression posttranscriptionally by inhibiting translation and by expediting deadenylation so as to trigger rapid mRNA decay. Their regulatory influence is mediated by the protein components of the RNA-induced silencing complex (RISC), which deliver miRNAs and siRNAs to their mRNA targets. Here, we present evidence that CCR4-NOT is the deadenylase that removes poly(A) from messages destabilized by miRNAs in human cells. Overproducing a mutationally inactivated form of either of the catalytic subunits of this deadenylase (CCR4 or CAF1/POP2) significantly impedes the deadenylation and decay of mRNA targeted by a partially complementary miRNA. The same deadenylase initiates the degradation of "off-target" mRNAs that are bound by an imperfectly complementary siRNA introduced by transfection. The greater inhibitory effect of inactive CAF1 or POP2 (versus inactive CCR4) suggests a predominant role for this catalytic subunit of CCR4-NOT in miRNA- or small interfering RNA (siRNA)-mediated deadenylation. These effects of mi/siRNAs and CCR4-NOT can be fully reproduced by directly tethering RISC to mRNA without the guidance of a small RNA, indicating that the ability of RISC to accelerate deadenylation is independent of RNA base pairing. Despite its importance for mi/siRNA-mediated deadenylation, CCR4-NOT appears not to associate significantly with RISC, as judged by the failure of CAF1 and POP2 to coimmunoprecipitate detectably with either the Ago or TNRC6 subunit of RISC, a finding at odds with deadenylase recruitment as the mechanism by which RISC accelerates poly(A) removal.

Carcinogenic Parasite Secretes Growth Factor That Accelerates Wound Healing and Potentially Promotes Neoplasia

PubMed Central

Smout, Michael J.; Sotillo, Javier; Laha, Thewarach; Papatpremsiri, Atiroch; Rinaldi, Gabriel; Pimenta, Rafael N.; Chan, Lai Yue; Johnson, Michael S.; Turnbull, Lynne; Whitchurch, Cynthia B.; Giacomin, Paul R.; Moran, Corey S.; Golledge, Jonathan; Daly, Norelle; Sripa, Banchob; Mulvenna, Jason P.

2015-01-01

Abstract Infection with the human liver fluke Opisthorchis viverrini induces cancer of the bile ducts, cholangiocarcinoma (CCA). Injury from feeding activities of this parasite within the human biliary tree causes extensive lesions, wounds that undergo protracted cycles of healing, and re-injury over years of chronic infection. We show that O. viverrini secreted proteins accelerated wound resolution in human cholangiocytes, an outcome that was compromised following silencing of expression of the fluke-derived gene encoding the granulin-like growth factor, Ov-GRN-1. Recombinant Ov-GRN-1 induced angiogenesis and accelerated mouse wound healing. Ov-GRN-1 was internalized by human cholangiocytes and induced gene and protein expression changes associated with wound healing and cancer pathways. Given the notable but seemingly paradoxical properties of liver fluke granulin in promoting not only wound healing but also a carcinogenic microenvironment, Ov-GRN-1 likely holds marked potential as a therapeutic wound-healing agent and as a vaccine against an infection-induced cancer of major public health significance in the developing world. PMID:26485648

Geographically Modified PageRank Algorithms: Identifying the Spatial Concentration of Human Movement in a Geospatial Network

PubMed Central

2015-01-01

A network approach, which simplifies geographic settings as a form of nodes and links, emphasizes the connectivity and relationships of spatial features. Topological networks of spatial features are used to explore geographical connectivity and structures. The PageRank algorithm, a network metric, is often used to help identify important locations where people or automobiles concentrate in the geographical literature. However, geographic considerations, including proximity and location attractiveness, are ignored in most network metrics. The objective of the present study is to propose two geographically modified PageRank algorithms—Distance-Decay PageRank (DDPR) and Geographical PageRank (GPR)—that incorporate geographic considerations into PageRank algorithms to identify the spatial concentration of human movement in a geospatial network. Our findings indicate that in both intercity and within-city settings the proposed algorithms more effectively capture the spatial locations where people reside than traditional commonly-used network metrics. In comparing location attractiveness and distance decay, we conclude that the concentration of human movement is largely determined by the distance decay. This implies that geographic proximity remains a key factor in human mobility. PMID:26437000

Expressed Glycosylphosphatidylinositol-Anchored Horseradish Peroxidase Identifies Co-Clustering Molecules in Individual Lipid Raft Domains

PubMed Central

Miyagawa-Yamaguchi, Arisa; Kotani, Norihiro; Honke, Koichi

2014-01-01

Lipid rafts that are enriched in glycosylphosphatidylinositol (GPI)-anchored proteins serve as a platform for important biological events. To elucidate the molecular mechanisms of these events, identification of co-clustering molecules in individual raft domains is required. Here we describe an approach to this issue using the recently developed method termed enzyme-mediated activation of radical source (EMARS), by which molecules in the vicinity within 300 nm from horseradish peroxidase (HRP) set on the probed molecule are labeled. GPI-anchored HRP fusion proteins (HRP-GPIs), in which the GPI attachment signals derived from human decay accelerating factor and Thy-1 were separately connected to the C-terminus of HRP, were expressed in HeLa S3 cells, and the EMARS reaction was catalyzed by these expressed HRP-GPIs under a living condition. As a result, these different HRP-GPIs had differences in glycosylation and localization and formed distinct clusters. This novel approach distinguished molecular clusters associated with individual GPI-anchored proteins, suggesting that it can identify co-clustering molecules in individual raft domains. PMID:24671047

Difference in Ulex europaeus agglutinin I-binding activity of decay-accelerating factor detected in the stools of patients with colorectal cancer and ulcerative colitis.

PubMed

Okazaki, Hiroaki; Mizuno, Motowo; Nasu, Junichirou; Makidono, Chiho; Hiraoka, Sakiko; Yamamoto, Kazuhide; Okada, Hiroyuki; Fujita, Teizo; Tsuji, Takao; Shiratori, Yasushi

2004-03-01

Expression of decay-accelerating factor (DAF, CD55), a complement-regulatory glycoprotein, is enhanced in colorectal-cancer (CC) cells and colonic epithelium in ulcerative colitis (UC), and stools from these patients contain increased amounts of DAF. Carbohydrate chains of glycoproteins are often altered during malignant transformation or inflammation. In this study, we investigated whether DAF molecules in patients with CC and those with UC differ with respect to oligosaccharide side chains. We analyzed DAF in stools and homogenates of colonic-tissue specimens obtained from patients with CC or UC using solid-phase enzyme-linked assay and Western blotting for reactivity with the lectins Ulex europaeus agglutinin I (UEA-I), wheat-germ agglutinin, peanut agglutinin, and concanavalin A. UEA-I bound to DAF in stools from patients with UC but not in that from the stools of CC patients, as demonstrated on the solid-phase enzyme-linked assay (P <.05, Mann-Whitney U test) and Western blotting. Binding of UEA-I was specifically inhibited by the addition of fucose. The difference in UEA-I reactivity with DAF was observed also in colonic-tissue homogenates from patients with UC and those with CC. DAF expressed in the mucosa and excreted into the stools of UC patients is different from that expressed in CC with regard to UEA-I reactivity. Future studies should be directed toward determining whether a qualitatively unique isoform of DAF is present, of which sugar chains are specific to CC in UC patients.

32-channel 3 Tesla receive-only phased-array head coil with soccer-ball element geometry.

PubMed

Wiggins, G C; Triantafyllou, C; Potthast, A; Reykowski, A; Nittka, M; Wald, L L

2006-07-01

A 32-channel 3T receive-only phased-array head coil was developed for human brain imaging. The helmet-shaped array was designed to closely fit the head with individual overlapping circular elements arranged in patterns of hexagonal and pentagonal symmetry similar to that of a soccer ball. The signal-to-noise ratio (SNR) and noise amplification (g-factor) in accelerated imaging applications were quantitatively evaluated in phantom and human images and compared with commercially available head coils. The 32-channel coil showed SNR gains of up to 3.5-fold in the cortex and 1.4-fold in the corpus callosum compared to a (larger) commercial eight-channel head coil. The experimentally measured g-factor performance of the helmet array showed significant improvement compared to the eight-channel array (peak g-factor 59% and 26% of the eight-channel values for four- and fivefold acceleration). The performance of the arrays is demonstrated in high-resolution and highly accelerated brain images. Copyright (c) 2006 Wiley-Liss, Inc.

Immunogenicity of HILDA/LIF either in a soluble or in a membrane anchored form expressed in vivo by recombinant vaccinia viruses.

PubMed

Taupin, J L; Acres, B; Dott, K; Schmitt, D; Kieny, M P; Gualde, N; Moreau, J F

1993-09-01

Insertion of various cDNAs in the genome of the vaccinia virus (VV) enables the in vivo and in vitro study of the functional role and/or the immunogenicity of the virally encoded recombinant proteins. We have prepared a recombinant VV expressing the cDNA of the human cytokine HILDA/LIF (human interleukin for DA cells/leukaemia inhibitory factor), and used this virus to immunize mice against this protein, which is very homologous to its murine counterpart (approximately 80% homology). We also constructed and expressed by the same system a chimeric gene encoding the HILDA/LIF protein fused to the 37 COOH-terminal amino-acids of the human decay accelerating factor (DAF). This sequence proved to be sufficient for the targeting of the fusion protein to the cell membrane, where it is linked to the phosphatidylinositols. Both recombinant VVs induced cytokine-specific antibodies in mice as analysed with an ELISA where the recombinant HILDA/LIF was plastic-coated and a cytofluorometric assay where the LIF-DAF molecule was present at the cell surface of stably transfected P815. In the latter case HILDA/LIF remained biologically active suggesting that it was expressed in its native form. The LIF-DAF fusion protein was found to exhibit a better capacity to elicit an antibody response against the native form of the cytokine as detected in cytofluorometric assays. Whatever the recombinant virus used to immunize the mice, the MoAbs obtained were positive either in the ELISA or in the cytofluorometric assays but one, which suggested that the plastic coating induced a conformational change of HILDA/LIF.

Assessment of biodeterioration for the screening of new wood preservatives : calculation of stiffness loss in rapid decay testing

Treesearch

Simon R. Przewloka; Douglas M. Crawford; Douglas R. Rammer; Donald L. Buckner; Bessie M. Woodward; Gan Li; Darrel D. Nicholas

2008-01-01

Demand for the development of environmentally benign wood preservatives has increased significantly. To reduce the evaluation time of prospective candidates, reliable accelerated decay methodologies are necessary for laboratory screening of potential preservatives. Ongoing research at Mississippi State University has focused upon utilizing custom built equipment to...

Neutrino Physics with Accelerator Driven Subcritical Reactors

NASA Astrophysics Data System (ADS)

Ciuffoli, Emilio

2017-09-01

Accelerator Driven Subcritical System (ADS) reactors are being developed around the world, to produce energy and, at the same time, to provide an efficient way to dispose of and to recycle nuclear waste. Used nuclear fuel, by itself, cannot sustain a chain reaction; however in ADS reactors the additional neutrons which are required will be supplied by a high-intensity accelerator. This accelerator will produce, as a by-product, a large quantity of {\\bar{ν }}μ via muon Decay At Rest (µDAR). Using liquid scintillators, it will be possible to to measure the CP-violating phase δCP and to look for experimental signs of the presence of sterile neutrinos in the appearance channel, testing the LSND and MiniBooNE anomalies. Even in the first stage of the project, when the beam energy will be lower, it will be possible to produce {\\bar{ν }}e via Isotope Decay At Rest (IsoDAR), which can be used to provide competitive bounds on sterile neutrinos in the disappearance channel. I will consider several experimental setups in which the antineutrinos are created using accelerators that will be constructed as part of the China-ADS program.

Application of accelerator sources for pulsed neutron logging of oil and gas wells

NASA Astrophysics Data System (ADS)

Randall, R. R.

1985-05-01

Dresser Atlas introduced the first commercial pulsed neutron oil well log in the early 1960s. This log had the capability of differentiating oil from salt water in a completed well. In the late 1970s the first continuous carbon/oxygen (C/O) log capable of differentiating oil from fresh water was introduced. The sources used in these commercial logs are radial geometry deuterium-tritium reaction devices with Cockcroft-Walton voltage multipliers providing the accelerator voltage. The commercial logging tools using these accelerators are comprised of scintillators detectors, power supplies, line drivers and receivers, and various timing and communications electronics. They are used to measure either the time decay or energy spectra of neutron-induced gamma events. The time decay information is useful in determining the neutron capture cross section, and the energy spectra is used to characterize inelastic neutron events.

Exploring the Role of Overlying Fields and Flare Ribbons in CME Speeds

NASA Astrophysics Data System (ADS)

Deng, M.; Welsch, B. T.

2013-12-01

The standard model of eruptive, two-ribbon flares involves reconnection of overlying magnetic fields beneath a rising ejection. Numerous observers have reported evidence linking this reconnection, indicated by photospheric flux swept out by flare ribbons, to coronal mass ejection (CME) acceleration. This acceleration might be caused by reconnected fields that wrap around the ejection producing an increased outward "hoop force." Other observations have linked stronger overlying fields, measured by the power-law index of the fitted decay rate of field strengths overlying eruption sites, to slower CME speeds. This might be caused by greater downward magnetic tension in stronger overlying fields. So overlying fields might both help and hinder the acceleration of CMEs: reconnection that converts overlying fields into flux winding about the ejection might help, but unreconnected overlying fields might hurt. Here, we investigate the roles of both ribbon fluxes and the decay rates of overlying fields in a set of eruptive events.

Accelerated decay rates drive soil organic matter persistence and storage in temperate forests via greater mineral stabilization of microbial residues.

NASA Astrophysics Data System (ADS)

Phillips, R.; Craig, M.; Turner, B. L.; Liang, C.

2017-12-01

Climate predicts soil organic matter (SOM) stocks at the global scale, yet controls on SOM stocks at finer spatial scales are still debated. A current hypothesis predicts that carbon (C) and nitrogen (N) storage in soils should be greater when decomposition is slow owing to microbial competition for nutrients or the recalcitrance of organic substrates (hereafter the `slow decay' hypothesis). An alternative hypothesis predicts that soil C and N storage should be greater in soils with rapid decomposition, owing to the accelerated production of microbial residues and their stabilization on soil minerals (hereafter the `stabilization hypothesis'). To test these alternative hypotheses, we quantified soil C and N to 1-m depth in temperate forests across the Eastern and Midwestern US that varied in their biotic, climatic, and edaphic properties. At each site, we sampled (1) soils dominated by arbuscular mycorrhizal (AM) tree species, which typically have fast decay rates and accelerated N cycling, (2) soils dominated by ectomycorrhizal (ECM) tree species, which generally have slow decay rates and slow N cycling, and (3) soils supporting both AM and ECM trees. To the extent that trees and theor associated microbes reflect and reinforce soil conditions, support for the slow decay hypothesis would be greater SOM storage in ECM soils, whereas support for the stabilization hypothesis would be greater SOM storage in AM soils. We found support for both hypotheses, as slow decomposition in ECM soils increased C and N storage in topsoil, whereas fast decomposition in AM soils increased C and N storage in subsoil. However, at all sites we found 57% greater total C and N storage in the entire profile in AM- soils (P < 0.0001), supporting the stabilization hypothesis. Amino sugar biomarkers (an indicator of microbial necromass) and particle size fractionation revealed that the greater SOM storage in AM soils was driven by an accumulation of microbial residues on clay minerals and metal oxides. Taken together, our results indicate that tree species influence soil C and N storage owing to how differences in decay rates affect mineral stabilization of organic matter. Further, our findings indicate that slow decay promotes soil C and N stocks at the soil surface, whereas fast decay promotes greater soil C and N stocks at depth.

Recent advances in biomedical applications of accelerator mass spectrometry.

PubMed

Hah, Sang Soo; Henderson, Paul T; Turteltaub, Kenneth W

2009-06-17

The use of radioisotopes has a long history in biomedical science, and the technique of accelerator mass spectrometry (AMS), an extremely sensitive nuclear physics technique for detection of very low-abundant, stable and long-lived isotopes, has now revolutionized high-sensitivity isotope detection in biomedical research, because it allows the direct determination of the amount of isotope in a sample rather than measuring its decay, and thus the quantitative analysis of the fate of the radiolabeled probes under the given conditions. Since AMS was first used in the early 90's for the analysis of biological samples containing enriched 14C for toxicology and cancer research, the biomedical applications of AMS to date range from in vitro to in vivo studies, including the studies of 1) toxicant and drug metabolism, 2) neuroscience, 3) pharmacokinetics, and 4) nutrition and metabolism of endogenous molecules such as vitamins. In addition, a new drug development concept that relies on the ultrasensitivity of AMS, known as human microdosing, is being used to obtain early human metabolism information of candidate drugs. These various aspects of AMS are reviewed and a perspective on future applications of AMS to biomedical research is provided.

Recent advances in biomedical applications of accelerator mass spectrometry

PubMed Central

Hah, Sang Soo

2009-01-01

The use of radioisotopes has a long history in biomedical science, and the technique of accelerator mass spectrometry (AMS), an extremely sensitive nuclear physics technique for detection of very low-abundant, stable and long-lived isotopes, has now revolutionized high-sensitivity isotope detection in biomedical research, because it allows the direct determination of the amount of isotope in a sample rather than measuring its decay, and thus the quantitative analysis of the fate of the radiolabeled probes under the given conditions. Since AMS was first used in the early 90's for the analysis of biological samples containing enriched 14C for toxicology and cancer research, the biomedical applications of AMS to date range from in vitro to in vivo studies, including the studies of 1) toxicant and drug metabolism, 2) neuroscience, 3) pharmacokinetics, and 4) nutrition and metabolism of endogenous molecules such as vitamins. In addition, a new drug development concept that relies on the ultrasensitivity of AMS, known as human microdosing, is being used to obtain early human metabolism information of candidate drugs. These various aspects of AMS are reviewed and a perspective on future applications of AMS to biomedical research is provided. PMID:19534792

Polyanion-Induced Self Association of Complement Factor H1

PubMed Central

Pangburn, Michael K.; Rawal, Nenoo; Cortes, Claudio; Alam, M. Nurul; Ferreira, Viviana P.; Atkinson, Mark A. L.

2008-01-01

Factor H is the primary soluble regulator of activation of the alternative pathway of complement. It prevents activation of complement on host cells and tissues upon association with C3b and surface polyanions such as sialic acids, heparin and other glycosaminoglycans. Here we show that interaction with polyanions causes self-association forming tetramers of the 155,000 Da glycosylated protein. Monomeric human factor H is an extended flexible protein that exhibits an apparent size of 330,000 Da, relative to globular standards, during gel filtration chromatography in the absence of polyanions. In the presence of dextran sulfate (5,000 Da) or heparin an intermediate species of apparent m.w. 700,000 and a limit species of m.w. 1,400,000 were observed by gel filtration. Sedimentation equilibrium analysis by analytical ultracentrifugation indicated a monomer Mr of 163,000 in the absence of polyanions and a Mr of 607,000, corresponding to a tetramer, in the presence of less than a 2-fold molar excess of dextran sulfate. Increasing concentrations of dextran sulfate increased binding of factor H to zymosan-C3b 4.5-fold. This was accompanied by an increase in both the decay accelerating and cofactor activity of factor H on these cells. An expressed fragment encompassing the C-terminal polyanion binding site (complement control protein domains 18–20) also exhibited polyanion-induced self association, suggesting that the C-terminal ends of factor H mediate self-association. The results suggest that recognition of polyanionic markers on host cells and tissues by factor H, and the resulting regulation of complement activation, may involve formation of dimers and tetramers of factor H. PMID:19124749

Disentangling the drivers of coarse woody debris behavior and carbon gas emissions during fire

NASA Astrophysics Data System (ADS)

Zhao, Weiwei; van der Werf, Guido R.; van Logtestijn, Richard S. P.; van Hal, Jurgen R.; Cornelissen, Johannes H. C.

2016-04-01

The turnover of coarse woody debris, a key terrestrial carbon pool, plays fundamental roles in global carbon cycling. Biological decomposition and fire are two main fates for dead wood turnover. Compared to slow decomposition, fire rapidly transfers organic carbon from the earth surface to the atmosphere. Both a-biotic environmental factors and biotic wood properties determine coarse wood combustion and thereby its carbon gas emissions during fire. Moisture is a key inhibitory environmental factor for fire. The properties of dead wood strongly affect how it burns either directly or indirectly through interacting with moisture. Coarse wood properties vary between plant species and between various decay stages. Moreover, if we put a piece of dead wood in the context of a forest fuel bed, the soil and wood contact might also greatly affect their fire behavior. Using controlled laboratory burns, we disentangled the effects of all these driving factors: tree species (one gymnosperms needle-leaf species, three angiosperms broad-leaf species), wood decay stages (freshly dead, middle decayed, very strongly decayed), moisture content (air-dried, 30% moisture content in mass), and soil-wood contact (on versus 3cm above the ground surface) on dead wood flammability and carbon gas efflux (CO2 and CO released in grams) during fire. Wood density was measured for all coarse wood samples used in our experiment. We found that compared to other drivers, wood decay stages have predominant positive effects on coarse wood combustion (for wood mass burned, R2=0.72 when air-dried and R2=0.52 at 30% moisture content) and associated carbon gas emissions (for CO2andCO (g) released, R2=0.55 when air-dried and R2=0.42 at 30% moisture content) during fire. Thus, wood decay accelerates wood combustion and its CO2 and CO emissions during fire, which can be mainly attributed to the decreasing wood density (for wood mass burned, R2=0.91 when air-dried and R2=0.63 at 30% moisture content) as wood becomes more decomposed. Our results provide quantitative experimental evidence for how several key abiotic and biotic factors, especially moisture content and the key underlying trait wood density, as well as their interactions, together drive coarse wood carbon turnover through fire. Our experimental data on coarse wood behavior and gas efflux during fire will help to improve the predictive power of global vegetation climate models on dead wood turnover and its feedback to climate.

A human factors approach to snowsport safety: Novel research on pediatric participants' behaviors and head injury risk.

PubMed

Dickson, Tracey J; Trathen, Stephen; Waddington, Gordon; Terwiel, F Anne; Baltis, Daniel

2016-03-01

This study applied a human factors approach to snowsport resort systems to contribute to the understanding of the incidence and severity of pediatric snowsport head accelerations. Previous research indicates low magnitude head accelerations are common among snowsport participants. This study adds to the knowledge of snowsport safety by measuring aspects of participants' snowsport behavior and linking this with head acceleration data. School-aged students (n = 107) wore telemetry-fitted helmets and Global Positioning System (GPS) devices during snowsport activity. Data was collected over 159 sessions (total hours 701). Head accelerations recorded by the telemetry units were compared with GPS-generated data. This study found speeds attained normally exceed the testing rating for which helmets are designed; lower rates of head accelerations compared to earlier studies and that when head accelerations did occur they were generally below the threshold for concussions. Pediatric snowsport head accelerations are rare and are generally of low magnitude. Those most at risk of a head acceleration >40 g were male snowboarders. Given the recorded speeds in first time participants, increased targeting of novice snowsport participants to encourage education about the use of protective equipment, including helmets, is warranted. Post event recall was not a good indicator of having experienced a head impact. Consideration should be given to raising the standard design speed testing for snowsport helmet protective devices to reflect actual snowsport behaviors. Copyright © 2015 Elsevier Ltd and The Ergonomics Society. All rights reserved.

Concepts in the development of new accelerated test methods for wood decay

Treesearch

Darrel D. Nicholas; Douglas Crawford

2003-01-01

Efforts to develop new environmentally friendly wood preservatives are seriously handicapped by the extended time period required to carry out the evaluation needed to establish confidence in the long term performance of new preservative systems. Studies in our laboratory have shown that using strength loss as a measure of the extent of wood decay makes it possible to...

When a tree falls: Controls on wood decay predict standing dead tree fall and new risks in changing forests

Treesearch

Brad Oberle; Kiona Ogle; Amy E. Zanne; Christopher W. Woodall

2018-01-01

When standing dead trees (snags) fall, they have major impacts on forest ecosystems. Snag fall can redistribute wildlife habitat and impact public safety, while governing important carbon (C) cycle consequences of tree mortality because ground contact accelerates C emissions during deadwood decay. Managing the consequences of altered snag dynamics in changing forests...

Neutrino masses, neutrino oscillations, and cosmological implications

NASA Technical Reports Server (NTRS)

Stecker, F. W.

1982-01-01

Theoretical concepts and motivations for considering neutrinos having finite masses are discussed and the experimental situation on searches for neutrino masses and oscillations is summarized. The solar neutrino problem, reactor, deep mine and accelerator data, tri decay experiments and double beta-decay data are considered and cosmological implications and astrophysical data relating to neutrino masses are reviewed. The neutrino oscillation solution to the solar neutrino problem, the missing mass problem in galaxy halos and galaxy cluster galaxy formation and clustering, and radiative neutrino decay and the cosmic ultraviolet background radiation are examined.

t anti-t production cross section measurement using soft electron tagging in p anti-p collisions at √s = 1.96-TeV

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chou, John Paul

2008-09-01

We measure the production cross section of tmore » $$\\bar{t}$$ events in p$$\\bar{p}$$ collisions at √s = 1.96 TeV. The data was collected by the CDF experiment in Run 2 of the Tevatron accelerator at the Fermi National Accelerator Laboratory between 2002 and 2007. 1.7 fb -1 of data was recorded during this time period. We reconstruct t$$\\bar{t}$$ events in the lepton+jets channel, whereby one W boson - resulting from the decay of the top quark pairs - decays leptonically and the other hadronically. The dominant background to this process is the production of W bosons in association with multiple jets. To distinguish t$$\\bar{t}$$ from background, we identify soft electrons from the semileptonic decay of heavy flavor jets produced in t$$\\bar{t}$$ events. We measure a cross section of σ $$\\bar{p}$$ = 7.8 ± 2.4(stat) ± 1.6(syst) ± 0.5(lumi).« less

Experimental studies for determining human discomfort response to vertical sinusoidal vibration

NASA Technical Reports Server (NTRS)

Dempsey, T. K.; Leatherwood, J. D.

1975-01-01

A study was conducted to investigate several problems related to methodology and design of experiments to obtain human comfort response to vertical sinusoidal vibration. Specifically, the studies were directed to the determination of (1) the adequacy of frequency averaging of vibration data to obtain discomfort predictors, (2) the effect of practice on subject ratings, (3) the effect of the demographic factors of age, sex, and weight, and (4) the relative importance of seat and floor vibrations in the determination of measurement and criteria specification location. Results indicate that accurate prediction of discomfort requires knowledge of both the acceleration level and frequency content of the vibration stimuli. More importantly, the prediction of discomfort was shown to be equally good based upon either floor accelerations or seat accelerations. Furthermore, it was demonstrated that the discomfort levels in different seats resulting from similar vibratory imputs were equal. Therefore, it was recommended that criteria specifications and acceleration measurements be made at the floor location. The results also indicated that practice did not systematically influence discomfort responses nor did the demographic factors of age, weight, and sex contribute to the discomfort response variation.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Stariha, Sarah; Macauley, Natalia; Sneed, Brian T.

The U.S. Department of Energy (DOE) set the 2020 durability target for polymer electrolyte membrane fuel cell transportation applications at 5000 hours. Since it is impractical to test every fuel cell for this length of time, there is ever increasing interest in developing accelerated stress tests (ASTs) that can accurately simulate the material component degradation in the membrane electrode assembly (MEA) observed under automotive operating conditions, but over a much shorter time frame. In this study, a square-wave catalyst AST was examined that shows a 5X time acceleration factor over the triangle-wave catalyst AST and a 25X time acceleration factormore » over the modified wet drive-cycle catalyst durability protocol, significantly decreasing the testing time. These acceleration factors were correlated to the platinum (Pt) particle size increase and associated decrease in electrochemical surface area (ECSA). This square-wave AST has been adopted by the DOE as a standard protocol to evaluate catalyst durability. We also compare three catalyst-durability protocols using state-of-the-art platinum-cobalt catalysts supported on high surface area carbon (SOA Pt-Co/HSAC) in the cathode catalyst layer. The results for each of the three tests showed both catalyst particle size increase and transition metal leaching. Moreover the acceleration factors for the alloy catalysts were smaller due to Co leaching being the predominant mechanism of voltage decay in ~5 nm PtCo/C catalysts. Finally, an extremely harsh carbon corrosion AST was run using the same SOA Pt-Co/HSAC catalyst. This showed minimal change in particle size and a low percentage Co loss from the cathode catalyst particles, despite a significant loss in catalyst layer thickness and cell performance. The carbon corrosion rates during these various ASTs were directly measured by monitoring the CO 2 emission from the cathode, further confirming the ability of the square-wave AST to evaluate the electro-catalyst independently of the support.« less

Spectroscopic Factors from the Single Neutron Pickup Reaction ^64Zn(d,t)

NASA Astrophysics Data System (ADS)

Leach, Kyle; Garrett, P. E.; Ball, G. C.; Bangay, J. C.; Bianco, L.; Demand, G. A.; Faestermann, T.; Finlay, P.; Green, K. L.; Hertenberger, R.; Krücken, R.; Phillips, A. A.; Rand, E. T.; Sumithrarachchi, C. S.; Svensson, C. E.; Triambak, S.; Wirth, H.-F.; Wong, J.

2009-10-01

A great deal of attention has recently been paid towards high-precision superallowed β-decay Ft values. With the availability of extremely high-precision (<0.1%) experimental data, precision on the individual Ft values are now dominated by the ˜1% theoretical corrections^[1]. This limitation is most evident in heavier superallowed nuclei (e.g. ^62Ga) where the isospin-symmetry-breaking (ISB) correction calculations become more difficult due to the truncated model space. Experimental spectroscopic factors for these nuclei are important for the identification of the relevant orbitals that should be included in the model space of the calculations. Motivated by this need, the single-nucleon transfer reaction ^64Zn(d,t)^63Zn was conducted at the Maier-Leibnitz-Laboratory (MLL) of TUM/LMU in Munich, Germany, using a 22 MeV polarized deuteron beam from the tandem Van de Graaff accelerator and the TUM/LMU Q3D magnetic spectrograph, with angular distributions from 10^o to 60^o. Results from this experiment will be presented and implications for calculations of ISB corrections in the superallowed &+circ; decay of ^62Ga will be discussed.^[1] I.S. Towner and J.C. Hardy, Phys. Rev. C 77, 025501 (2008).

VEGF preconditioning leads to stem cell remodeling and attenuates age-related decay of adult hippocampal neurogenesis

PubMed Central

Licht, Tamar; Rothe, Gadiel; Kreisel, Tirzah; Wolf, Brachi; Benny, Ofra; Rooney, Alasdair G.; ffrench-Constant, Charles; Enikolopov, Grigori; Keshet, Eli

2016-01-01

Several factors are known to enhance adult hippocampal neurogenesis but a factor capable of inducing a long-lasting neurogenic enhancement that attenuates age-related neurogenic decay has not been described. Here, we studied hippocampal neurogenesis following conditional VEGF induction in the adult brain and showed that a short episode of VEGF exposure withdrawn shortly after the generation of durable new vessels (but not under conditions where newly made vessels failed to persist) is sufficient for neurogenesis to proceed at a markedly elevated level for many months later. Continual neurogenic increase over several months was not accompanied by accelerated exhaustion of the neuronal stem cell (NSC) reserve, thereby allowing neurogenesis to proceed at a markedly elevated rate also in old mice. Neurogenic enhancement by VEGF preconditioning was, in part, attributed to rescue of age-related NSC quiescence. Remarkably, VEGF caused extensive NSC remodelling manifested in transition of the enigmatic NSC terminal arbor onto long cytoplasmic processes engaging with and spreading over even remote blood vessels, a configuration reminiscent of early postnatal “juvenile” NSCs. Together, these findings suggest that VEGF preconditioning might be harnessed for long-term neurogenic enhancement despite continued exposure to an “aged” systemic milieu. PMID:27849577

Guidelines for Safe Human Exposure to Impact Acceleration. Update A

DTIC Science & Technology

1989-09-01

and +Y directions were mostly medically insignificant [4]. (4) One subject had pain radiating to his left arm after a +Y expost -re. This condition was... factor . The "Eiband curves" [7] for human wholebody tolerance to impact ac- celeration exposures are based on work with humans and chimpanzees...problems such as severe strains precede head injury, and therefore neck injury is the limiting factor in defining maximum impact exposures. Forces and

Comparison of effectiveness of wood decay fungi maintained by annual subculture on agar and stored in sterile water for 18 years.

PubMed

Richter, Dana L; Kangas, Laura C; Smith, Jill K; Laks, Peter E

2010-03-01

Fourteen isolates of basidiomycete decay fungi (12 species) were maintained for 18 years on agar slants transferred annually and also stored as mycelium-agar cores under cold sterile water without subculture. Isolates stored by each method were evaluated for decay effectiveness using a standard laboratory accelerated soil-block decay test. Effectiveness was measured by mean percent mass loss of wood blocks. There was no significant difference (p < or = 0.05) in decay effectiveness between storage methods for 12 of the fungus isolates tested. For the 2 fungi that showed a significant difference in the amount of decay with respect to storage method, 1 fungus (Fomitopsis lilacinogilva) produced more decay by the strain maintained as an agar slant, while the other fungus (Trametes versicolor) produced more decay by the strain stored in sterile water. Results suggested that storage under sterile water is an easy and effective method to store isolates of decay fungi for long periods, but as with any microbial storage method, careful monitoring of isolates upon revival is necessary.

Decay heat uncertainty quantification of MYRRHA

NASA Astrophysics Data System (ADS)

Fiorito, Luca; Buss, Oliver; Hoefer, Axel; Stankovskiy, Alexey; Eynde, Gert Van den

2017-09-01

MYRRHA is a lead-bismuth cooled MOX-fueled accelerator driven system (ADS) currently in the design phase at SCK·CEN in Belgium. The correct evaluation of the decay heat and of its uncertainty level is very important for the safety demonstration of the reactor. In the first part of this work we assessed the decay heat released by the MYRRHA core using the ALEPH-2 burnup code. The second part of the study focused on the nuclear data uncertainty and covariance propagation to the MYRRHA decay heat. Radioactive decay data, independent fission yield and cross section uncertainties/covariances were propagated using two nuclear data sampling codes, namely NUDUNA and SANDY. According to the results, 238U cross sections and fission yield data are the largest contributors to the MYRRHA decay heat uncertainty. The calculated uncertainty values are deemed acceptable from the safety point of view as they are well within the available regulatory limits.

Ultra-High Precision Half-Life Measurement for the Superallowed &+circ; Emitter ^26Al^m

NASA Astrophysics Data System (ADS)

Finlay, P.; Demand, G.; Garrett, P. E.; Leach, K. G.; Phillips, A. A.; Sumithrarachchi, C. S.; Svensson, C. E.; Triambak, S.; Grinyer, G. F.; Leslie, J. R.; Andreoiu, C.; Cross, D.; Austin, R. A. E.; Ball, G. C.; Bandyopadhyay, D.; Djongolov, M.; Ettenauer, S.; Hackman, G.; Pearson, C. J.; Williams, S. J.

2009-10-01

The calculated nuclear structure dependent correction for ^26Al^m (δC-δNS= 0.305(27)% [1]) is smaller by nearly a factor of two than the other twelve precision superallowed cases, making it an ideal case to pursue a reduction in the experimental errors contributing to the Ft value. An ultra-high precision half-life measurement for the superallowed &+circ; emitter ^26Al^m has been made at the Isotope Separator and Accelerator (ISAC) facility at TRIUMF in Vancouver, Canada. A beam of ˜10^5 ^26Al^m/s was delivered in October 2007 and its decay was observed using a 4π continuous gas flow proportional counter as part of an ongoing experimental program in superallowed Fermi β decay studies. With a statistical precision of ˜0.008%, the present work represents the single most precise measurement of any superallowed half-life to date. [4pt] [1] I.S. Towner and J.C. Hardy, Phys. Rev. C 79, 055502 (2009).

Absence of Gal epitope prolongs survival of swine lungs in an ex vivo model of hyperacute rejection

PubMed Central

Nguyen, Bao-Ngoc H.; Azimzadeh, Agnes M.; Schroeder, Carsten; Buddensick, Thomas; Zhang, Tianshu; Laaris, Amal; Cochrane, Megan; Schuurman, Henk-Jan; Sachs, David H.; Allan, James S.; Pierson, Richard N.

2012-01-01

Background Galactosyl transferase gene knock-out (GalTKO) swine offer a unique tool to evaluate the role of the Gal antigen in xenogenic lung hyperacute rejection. Methods We perfused GalTKO miniature swine lungs with human blood. Results were compared with those from previous studies using wild-type and human decay-accelerating factor-transgenic (hDAF+/+) pig lungs. Results GalTKO lungs survived 132 ± 52 min compared to 10 ± 9 min for wild-type lungs (P = 0.001) and 45 ± 60 min for hDAF+/+ lungs (P = 0.18). GalTKO lungs displayed stable physiologic flow and pulmonary vascular resistance (PVR) until shortly before graft demise, similar to autologous perfusion, and unlike wild-type or hDAF+/+ lungs. Early (15 and 60 min) complement (C3a) and platelet activation and intrapulmonary platelet deposition were significantly diminished in GalTKO lungs relative to wild-type or hDAF+/+ lungs. However, GalTKO lungs adsorbed cytotoxic anti-non-Gal antibody and elaborated high levels of thrombin; their demise was associated with increased PVR, capillary congestion, intravascular thrombi and strong CD41 deposition not seen at earlier time points. Conclusions In summary, GalTKO lungs are substantially protected from injury but, in addition to anti-non-Gal antibody and complement, platelet adhesion and non-physiologic intravascular coagulation contribute to Gal-independent lung injury mechanisms. PMID:21496117

Implications of Secondary Aftershocks for Failure Processes

NASA Astrophysics Data System (ADS)

Gross, S. J.

2001-12-01

When a seismic sequence with more than one mainshock or an unusually large aftershock occurs, there is a compound aftershock sequence. The secondary aftershocks need not have exactly the same decay as the primary sequence, with the differences having implications for the failure process. When the stress step from the secondary mainshock is positive but not large enough to cause immediate failure of all the remaining primary aftershocks, failure processes which involve accelerating slip will produce secondary aftershocks that decay more rapidly than primary aftershocks. This is because the primary aftershocks are an accelerated version of the background seismicity, and secondary aftershocks are an accelerated version of the primary aftershocks. Real stress perturbations may be negative, and heterogeneities in mainshock stress fields mean that the real world situation is quite complicated. I will first describe and verify my picture of secondary aftershock decay with reference to a simple numerical model of slipping faults which obeys rate and state dependent friction and lacks stress heterogeneity. With such a model, it is possible to generate secondary aftershock sequences with perturbed decay patterns, quantify those patterns, and develop an analysis technique capable of correcting for the effect in real data. The secondary aftershocks are defined in terms of frequency linearized time s(T), which is equal to the number of primary aftershocks expected by a time T, $ s ≡ ∫ t=0T n(t) dt, where the start time t=0 is the time of the primary aftershock, and the primary aftershock decay function n(t) is extrapolated forward to the times of the secondary aftershocks. In the absence of secondary sequences the function s(T)$ re-scales the time so that approximately one event occurs per new time unit; the aftershock sequence is gone. If this rescaling is applied in the presence of a secondary sequence, the secondary sequence is shaped like a primary aftershock sequence, and can be fit by the same modeling techniques applied to simple sequences. The later part of the presentation will concern the decay of Hector Mine aftershocks as influenced by the Landers aftershocks. Although attempts to predict the abundance of Hector aftershocks based on stress overlap analysis are not very successful, the analysis does do a good job fitting the decay of secondary sequences.

Physical Forces between Humans and How Humans Attract and Repel Each Other Based on Their Social Interactions in an Online World

PubMed Central

Thurner, Stefan; Fuchs, Benedikt

2015-01-01

Physical interactions between particles are the result of the exchange of gauge bosons. Human interactions are mediated by the exchange of messages, goods, money, promises, hostilities, etc. While in the physical world interactions and their associated forces have immediate dynamical consequences (Newton’s laws) the situation is not clear for human interactions. Here we quantify the relative acceleration between humans who interact through the exchange of messages, goods and hostilities in a massive multiplayer online game. For this game we have complete information about all interactions (exchange events) between about 430,000 players, and about their trajectories (movements) in the metric space of the game universe at any point in time. We use this information to derive “interaction potentials" for communication, trade and attacks and show that they are harmonic in nature. Individuals who exchange messages and trade goods generally attract each other and start to separate immediately after exchange events end. The form of the interaction potential for attacks mirrors the usual “hit-and-run" tactics of aggressive players. By measuring interaction intensities as a function of distance, velocity and acceleration, we show that “forces" between players are directly related to the number of exchange events. We find an approximate power-law decay of the likelihood for interactions as a function of distance, which is in accordance with previous real world empirical work. We show that the obtained potentials can be understood with a simple model assuming an exchange-driven force in combination with a distance-dependent exchange rate. PMID:26196505

Physical Forces between Humans and How Humans Attract and Repel Each Other Based on Their Social Interactions in an Online World.

PubMed

Thurner, Stefan; Fuchs, Benedikt

2015-01-01

Physical interactions between particles are the result of the exchange of gauge bosons. Human interactions are mediated by the exchange of messages, goods, money, promises, hostilities, etc. While in the physical world interactions and their associated forces have immediate dynamical consequences (Newton's laws) the situation is not clear for human interactions. Here we quantify the relative acceleration between humans who interact through the exchange of messages, goods and hostilities in a massive multiplayer online game. For this game we have complete information about all interactions (exchange events) between about 430,000 players, and about their trajectories (movements) in the metric space of the game universe at any point in time. We use this information to derive "interaction potentials" for communication, trade and attacks and show that they are harmonic in nature. Individuals who exchange messages and trade goods generally attract each other and start to separate immediately after exchange events end. The form of the interaction potential for attacks mirrors the usual "hit-and-run" tactics of aggressive players. By measuring interaction intensities as a function of distance, velocity and acceleration, we show that "forces" between players are directly related to the number of exchange events. We find an approximate power-law decay of the likelihood for interactions as a function of distance, which is in accordance with previous real world empirical work. We show that the obtained potentials can be understood with a simple model assuming an exchange-driven force in combination with a distance-dependent exchange rate.

Lipid suppression via double inversion recovery with symmetric frequency sweep for robust 2D‐GRAPPA‐accelerated MRSI of the brain at 7 T

PubMed Central

Hangel, Gilbert; Strasser, Bernhard; Považan, Michal; Gruber, Stephan; Chmelík, Marek; Gajdošík, Martin; Trattnig, Siegfried

2015-01-01

This work presents a new approach for high‐resolution MRSI of the brain at 7 T in clinically feasible measurement times. Two major problems of MRSI are the long scan times for large matrix sizes and the possible spectral contamination by the transcranial lipid signal. We propose a combination of free induction decay (FID)‐MRSI with a short acquisition delay and acceleration via in‐plane two‐dimensional generalised autocalibrating partially parallel acquisition (2D‐GRAPPA) with adiabatic double inversion recovery (IR)‐based lipid suppression to allow robust high‐resolution MRSI. We performed Bloch simulations to evaluate the magnetisation pathways of lipids and metabolites, and compared the results with phantom measurements. Acceleration factors in the range 2–25 were tested in a phantom. Five volunteers were scanned to verify the value of our MRSI method in vivo. GRAPPA artefacts that cause fold‐in of transcranial lipids were suppressed via double IR, with a non‐selective symmetric frequency sweep. The use of long, low‐power inversion pulses (100 ms) reduced specific absorption rate requirements. The symmetric frequency sweep over both pulses provided good lipid suppression (>90%), in addition to a reduced loss in metabolite signal‐to‐noise ratio (SNR), compared with conventional IR suppression (52–70%). The metabolic mapping over the whole brain slice was not limited to a rectangular region of interest. 2D‐GRAPPA provided acceleration up to a factor of nine for in vivo FID‐MRSI without a substantial increase in g‐factors (<1.1). A 64 × 64 matrix can be acquired with a common repetition time of ~1.3 s in only 8 min without lipid artefacts caused by acceleration. Overall, we present a fast and robust MRSI method, using combined double IR fat suppression and 2D‐GRAPPA acceleration, which may be used in (pre)clinical studies of the brain at 7 T. © 2015 The Authors. NMR in Biomedicine published by John Wiley & Sons Ltd. PMID:26370781

Lipid suppression via double inversion recovery with symmetric frequency sweep for robust 2D-GRAPPA-accelerated MRSI of the brain at 7 T.

PubMed

Hangel, Gilbert; Strasser, Bernhard; Považan, Michal; Gruber, Stephan; Chmelík, Marek; Gajdošík, Martin; Trattnig, Siegfried; Bogner, Wolfgang

2015-11-01

This work presents a new approach for high-resolution MRSI of the brain at 7 T in clinically feasible measurement times. Two major problems of MRSI are the long scan times for large matrix sizes and the possible spectral contamination by the transcranial lipid signal. We propose a combination of free induction decay (FID)-MRSI with a short acquisition delay and acceleration via in-plane two-dimensional generalised autocalibrating partially parallel acquisition (2D-GRAPPA) with adiabatic double inversion recovery (IR)-based lipid suppression to allow robust high-resolution MRSI. We performed Bloch simulations to evaluate the magnetisation pathways of lipids and metabolites, and compared the results with phantom measurements. Acceleration factors in the range 2-25 were tested in a phantom. Five volunteers were scanned to verify the value of our MRSI method in vivo. GRAPPA artefacts that cause fold-in of transcranial lipids were suppressed via double IR, with a non-selective symmetric frequency sweep. The use of long, low-power inversion pulses (100 ms) reduced specific absorption rate requirements. The symmetric frequency sweep over both pulses provided good lipid suppression (>90%), in addition to a reduced loss in metabolite signal-to-noise ratio (SNR), compared with conventional IR suppression (52-70%). The metabolic mapping over the whole brain slice was not limited to a rectangular region of interest. 2D-GRAPPA provided acceleration up to a factor of nine for in vivo FID-MRSI without a substantial increase in g-factors (<1.1). A 64 × 64 matrix can be acquired with a common repetition time of ~1.3 s in only 8 min without lipid artefacts caused by acceleration. Overall, we present a fast and robust MRSI method, using combined double IR fat suppression and 2D-GRAPPA acceleration, which may be used in (pre)clinical studies of the brain at 7 T. © 2015 The Authors. NMR in Biomedicine published by John Wiley & Sons Ltd.

Science 101: How Do People Design Safe Amusement Park Rides?

ERIC Educational Resources Information Center

Robertson, Bill

2015-01-01

To address the question of how people design safe amusement park rides, Bill Robertson focuses on the factors designers must consider so that human bodies don't experience too large an acceleration (any change in speed and/or direction) or "g-force" (the acceleration an object undergoes while freely falling, with no air resistance, under…

DOE Office of Scientific and Technical Information (OSTI.GOV)

Li, Wentao; Liu, Jiansheng, E-mail: michaeljs-liu@siom.ac.cn; Wang, Wentao

An electron beam with the maximum energy extending up to 1.8 GeV, much higher than the dephasing limit, is experimentally obtained in the laser wakefield acceleration with the plasma density of 3.5 × 10{sup 18} cm{sup −3}. With particle in cell simulations and theoretical analysis, we find that the laser intensity evolution plays a major role in the enhancement of the electron energy gain. While the bubble length decreases due to the intensity-decay of the laser pulse, the phase of the electron beam in the wakefield can be locked, which contributes to the overcoming of the dephasing. Moreover, the laser intensity evolution is describedmore » for the phase-lock acceleration of electrons in the uniform plasma, confirmed with our own simulation. Since the decaying of the intensity is unavoidable in the long distance propagation due to the pump depletion, the energy gain of the high energy laser wakefield accelerator can be greatly enhanced if the current process is exploited.« less

Elongation Factor Ts Directly Facilitates the Formation and Disassembly of the Escherichia coli Elongation Factor Tu·GTP·Aminoacyl-tRNA Ternary Complex*

PubMed Central

Burnett, Benjamin J.; Altman, Roger B.; Ferrao, Ryan; Alejo, Jose L.; Kaur, Navdep; Kanji, Joshua; Blanchard, Scott C.

2013-01-01

Aminoacyl-tRNA enters the translating ribosome in a ternary complex with elongation factor Tu (EF-Tu) and GTP. Here, we describe bulk steady state and pre-steady state fluorescence methods that enabled us to quantitatively explore the kinetic features of Escherichia coli ternary complex formation and decay. The data obtained suggest that both processes are controlled by a nucleotide-dependent, rate-determining conformational change in EF-Tu. Unexpectedly, we found that this conformational change is accelerated by elongation factor Ts (EF-Ts), the guanosine nucleotide exchange factor for EF-Tu. Notably, EF-Ts attenuates the affinity of EF-Tu for GTP and destabilizes ternary complex in the presence of non-hydrolyzable GTP analogs. These results suggest that EF-Ts serves an unanticipated role in the cell of actively regulating the abundance and stability of ternary complex in a manner that contributes to rapid and faithful protein synthesis. PMID:23539628

THE LU ISOTOPIC COMPOSITION OF ACHONDRITES: CLOSING THE CASE FOR ACCELERATED DECAY OF {sup 176}LU

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wimpenny, Josh; Yin, Qing-zhu; Amelin, Yuri, E-mail: jbwimpenny@ucdavis.edu

Studies of Lu–Hf isotope systematics in meteorites have produced apparent “ages” that are older than Pb–Pb ages and older than the estimated age of our solar system. One proposed explanation for this discrepancy is that irradiation by cosmic rays caused excitation of {sup 176}Lu to its short-lived isomer that then underwent rapid decay to {sup 176}Hf. This explanation can account for apparent excesses in {sup 176}Hf that correlate with Lu/Hf ratio. Mass balance requires that samples with measurable excess in {sup 176}Hf should also have measurable deficiencies in {sup 176}Lu on the order of 1‰–3‰. To unambiguously test the acceleratedmore » decay hypothesis, we have measured the {sup 176}Lu/{sup 175}Lu ratio in terrestrial materials and achondrites to search for evidence of depletion in {sup 176}Lu. To a precision of 0.1‰ terrestrial standards, cumulate and basaltic eucrites and angrites all have the same {sup 176}Lu/{sup 175}Lu ratio. Barring a subsequent mass-dependent fractionation event, these results suggest that the apparent excesses in {sup 176}Hf are not caused by accelerated decay of {sup 176}Lu, and so another hypothesis is required to explain apparently old Lu–Hf ages.« less

Flexural-gravity Wave Attenuation in a Thick Ice Shelf

NASA Astrophysics Data System (ADS)

Stephen, R. A.; Bromirski, P. D.; Gerstoft, P.; Chen, Z.; Wiens, D.; Aster, R. C.; Nyblade, A.

2016-12-01

A thirty-four station broadband seismic array was deployed on the Ross Ice Shelf, Antarctica from November 2014 to November 2017. Analyses indicate that phase speeds of infra-gravity wave and tsunami excitation in the 0.003 to 0.02 Hz band are 70 m/s, corresponding to the low frequency limit of flexural-gravity waves. Median spectral amplitudes in this band decay exponentially with distance from the shelf edge in a manner consistent with intrinsic attenuation. Seismic Q is typically 7-9, with an RMS amplitude decay of 0.04-0.05dB/km and an e-folding distance of 175-220 km. Amplitudes do not appear to drop crossing crevasse fields. Vertical and horizontal acceleration levels at stations on the floating ice shelf are 50 dB higher than those on grounded ice. Horizontal accelerations are about 15 dB higher than vertical accelerations. Median spectral levels at 0.003 Hz are within 6 dB for stations from 2 to 430 km from the shelf edge. In contrast, the levels drop by 90 dB at 0.02 Hz. Ocean gravity wave excitation has been proposed as a mechanism that can weaken ice shelves and potentially trigger disintegration events. These measurements indicate that the propensity for shelf weakening and disintegration decays exponentially with distance from the ice front for gravity waves in the 0.003 to 0.02Hz band.

Precision Branching Ratio Measurement for the Superallowed β+ Emitter Ga62 and Isospin-Symmetry-Breaking Corrections in A≥62 Nuclei

NASA Astrophysics Data System (ADS)

Hyland, B.; Svensson, C. E.; Ball, G. C.; Leslie, J. R.; Achtzehn, T.; Albers, D.; Andreoiu, C.; Bricault, P.; Churchman, R.; Cross, D.; Dombsky, M.; Finlay, P.; Garrett, P. E.; Geppert, C.; Grinyer, G. F.; Hackman, G.; Hanemaayer, V.; Lassen, J.; Lavoie, J. P.; Melconian, D.; Morton, A. C.; Pearson, C. J.; Pearson, M. R.; Phillips, A. A.; Schumaker, M. A.; Smith, M. B.; Towner, I. S.; Valiente-Dobón, J. J.; Wendt, K.; Zganjar, E. F.

2006-09-01

A high-precision branching ratio measurement for the superallowed β+ decay of Ga62 was performed at the Isotope Separator and Accelerator radioactive ion beam facility. Nineteen γ rays emitted following β+ decay of Ga62 were identified, establishing the dominant superallowed branching ratio to be (99.861±0.011)%. Combined with recent half-life and Q-value measurements, this branching ratio yields a superallowed ft value of 3075.6±1.4s for Ga62 decay. These results demonstrate the feasibility of high-precision superallowed branching ratio measurements in the A≥62 mass region and provide the first stringent tests of the large isospin-symmetry-breaking effects predicted for these decays.

Radiative decays of the Σ0(1385) and Λ(1520) hyperons

NASA Astrophysics Data System (ADS)

Taylor, S.; Mutchler, G. S.; Adams, G.; Ambrozewicz, P.; Anciant, E.; Anghinolfi, M.; Asavapibhop, B.; Asryan, G.; Audit, G.; Avakian, H.; Bagdasaryan, H.; Ball, J. P.; Barrow, S.; Batourine, V.; Battaglieri, M.; Beard, K.; Bektasoglu, M.; Bellis, M.; Benmouna, N.; Berman, B. L.; Bianchi, N.; Biselli, A. S.; Boiarinov, S.; Bonner, B. E.; Bouchigny, S.; Bradford, R.; Branford, D.; Briscoe, W. J.; Brooks, W. K.; Bültmann, S.; Burkert, V. D.; Butuceanu, C.; Calarco, J. R.; Carman, D. S.; Carnahan, B.; Chen, S.; Cole, P. L.; Cords, D.; Corvisiero, P.; Crabb, D.; Crannell, H.; Cummings, J. P.; Sanctis, E. De; Devita, R.; Degtyarenko, P. V.; Denizli, H.; Dennis, L.; Deur, A.; Dharmawardane, K. V.; Djalali, C.; Dodge, G. E.; Doughty, D.; Dragovitsch, P.; Dugger, M.; Dytman, S.; Dzyubak, O. P.; Egiyan, H.; Egiyan, K. S.; Elouadrhiri, L.; Empl, A.; Eugenio, P.; Fatemi, R.; Feldman, G.; Fersch, R. G.; Feuerbach, R. J.; Forest, T. A.; Funsten, H.; Garçon, M.; Gavalian, G.; Gilfoyle, G. P.; Giovanetti, K. L.; Golovatch, E.; Gordon, C. I.; Gothe, R. W.; Griffioen, K. A.; Guidal, M.; Guillo, M.; Guler, N.; Guo, L.; Gyurjyan, V.; Hadjidakis, C.; Hakobyan, R. S.; Hardie, J.; Heddle, D.; Hersman, F. W.; Hicks, K.; Hleiqawi, I.; Holtrop, M.; Hu, J.; Huertas, M.; Hyde-Wright, C. E.; Ilieva, Y.; Ireland, D. G.; Ito, M. M.; Jenkins, D.; Joo, K.; Juengst, H. G.; Kellie, J. D.; Khandaker, M.; Kim, K. Y.; Kim, K.; Kim, W.; Klein, A.; Klein, F. J.; Klimenko, A. V.; Klusman, M.; Kossov, M.; Koubarovski, V.; Kramer, L. H.; Kuhn, S. E.; Kuhn, J.; Lachniet, J.; Laget, J. M.; Langheinrich, J.; Lawrence, D.; Lee, T.; Li, Ji; Lima, A. C.; Livingston, K.; Lukashin, K.; Manak, J. J.; Marchand, C.; McAleer, S.; McNabb, J. W.; Mecking, B. A.; Melone, J. J.; Mestayer, M. D.; Meyer, C. A.; Mikhailov, K.; Mirazita, M.; Miskimen, R.; Mokeev, V.; Morand, L.; Morrow, S. A.; Muccifora, V.; Mueller, J.; Napolitano, J.; Nasseripour, R.; Niccolai, S.; Niculescu, G.; Niculescu, I.; Niczyporuk, B. B.; Niyazov, R. A.; Nozar, M.; O'Rielly, G. V.; Osipenko, M.; Ostrovidov, A. I.; Park, K.; Pasyuk, E.; Philips, S. A.; Pivnyuk, N.; Pocanic, D.; Pogorelko, O.; Polli, E.; Pozdniakov, S.; Preedom, B. M.; Price, J. W.; Prok, Y.; Protopopescu, D.; Qin, L. M.; Raue, B. S.; Riccardi, G.; Ricco, G.; Ripani, M.; Ritchie, B. G.; Ronchetti, F.; Rosner, G.; Rossi, P.; Rowntree, D.; Rubin, P. D.; Sabatié, F.; Salgado, C.; Santoro, J. P.; Sapunenko, V.; Schumacher, R. A.; Serov, V. S.; Shafi, A.; Sharabian, Y. G.; Shaw, J.; Simionatto, S.; Skabelin, A. V.; Smith, E. S.; Smith, L. C.; Sober, D. I.; Spraker, M.; Stavinsky, A.; Stepanyan, S.; Stepanyan, S. S.; Stokes, B. E.; Stoler, P.; Strakovsky, I. I.; Strauch, S.; Suleiman, R.; Taiuti, M.; Tedeschi, D. J.; Thoma, U.; Thompson, R.; Tkabladze, A.; Todor, L.; Tur, C.; Ungaro, M.; Vineyard, M. F.; Vlassov, A. V.; Wang, K.; Weinstein, L. B.; Weller, H.; Weygand, D. P.; Whisnant, C. S.; Williams, M.; Wolin, E.; Wood, M. H.; Yegneswaran, A.; Yun, J.; Zana, L.

2005-05-01

The electromagnetic decays of the Σ0(1385) and Λ(1520) hyperons were studied in photon-induced reactions γp→K+Λ(1116)γ in the Large Acceptance Spectrometer detector at the Thomas Jefferson National Accelerator Facility. We report the first observation of the radiative decay of the Σ0(1385) and a measurement of the Λ(1520) radiative decay width. For the Σ0(1385)→Λ(1116)γ transition, we measured a partial width of 479±120(stat)+81-100(sys)keV, larger than all of the existing model predictions. For the Λ(1520)→Λ(1116)γ transition, we obtained a partial width of 167±43(stat)+26-12(sys)keV.

β-γ and isomeric decay spectroscopy of 168Dy

NASA Astrophysics Data System (ADS)

Zhang, G. X.; Watanabe, H.; Kondev, F. G.; Lane, G. J.; Regan, P. H.; Söderström, P.-A.; Walker, P. M.; Kanaoka, H.; Korkulu, Z.; Lee, P. S.; Liu, J. J.; Nishimura, S.; Wu, J.; Yagi, A.; Ahn, D. S.; Alharbi, T.; Baba, H.; Browne, F.; Bruce, A. M.; Carroll, R. J.; Chae, K. Y.; Dombradi, Zs.; Doornenbal, P.; Estrade, A.; Fukuda, N.; Griffin, C.; Ideguchi, E.; Inabe, N.; Isobe, T.; Kanaya, S.; Kojouharov, I.; Kubo, T.; Kubono, S.; Kurz, N.; Kuti, I.; Lalkovski, S.; Lee, C. S.; Lee, E. J.; Lorusso, G.; Lotay, G.; Moon, C.-B.; Nishizuka, I.; Nita, C. R.; Odahara, A.; Patel, Z.; Phong, V. H.; Podolyák, Zs.; Roberts, O. J.; Sakurai, H.; Schaffner, H.; Shand, C. M.; Shimizu, Y.; Sumikama, T.; Suzuki, H.; Takeda, H.; Terashima, S.; Vajta, Zs.; Valiente-Dóbon, J. J.; Xu, Z. Y.

2018-05-01

This contribution will report on the experimental work on the level structure of 168Dy. The experimental data have been taken as part of the EURICA decay spectroscopy campaign at RIBF, RIKEN in November 2014. In the experiment, a 238U primary beam is accelerated up to 345 MeV/u with an average intensity of 12 pnA. The nuclei of interest are produced by in-flight fission of 238U impinging on Be target with a thickness of 5 mm. The excited states of 168Dy have been populated through the decay from a newly identified isomeric state and via the β decay from 168Tb. In this contribution, scientific motivations, experimental procedure and some preliminary results for this study are presented.

Experimental evidence for beta-decay as a source of chirality by enantiomer analysis

NASA Technical Reports Server (NTRS)

Bonner, W. A.

1984-01-01

Earlier experiments testing the Vester-Ulbricht beta-decay hypothesis for the origin of molecular chirality are reviewed, followed by descriptions of experiments involving attempted asymmetric radiolysis of DL-amino acids using quantitative gas chromotography as a probe for optical activity. The radiation sources included Sr-90-Y-90, C-14, and P-32 Bremsstrahlen, longitudinally polarized electrons from a linear accelerator and longitudinally polarized protons from a cyclotron. With the possible exception of the linear accelerator irradiations, these experiments failed to produce g.c.-detectable enantiomeric excesses, even at 50-70 percent gross radiolysis. Thus no unambiguous support for the Vester-Ulbricht hypothesis is found in any of the attempted asymmetric radiolyses performed to date. Radioracemization, a possible reason for these failures, is discussed.

Properties of transparent (Gd,Lu)3(Al,Ga)5O12:Ce ceramic with Mg, Ca and Ce co-dopants

NASA Astrophysics Data System (ADS)

Wang, Yimin; Baldoni, Gary; Brecher, Charles; Rhodes, William H.; Shirwadkar, Urmila; Glodo, Jarek; Shah, Ishaan; Ji, Chuncheng

2015-08-01

Cerium activated mixed lutetium/gadolinium- and aluminum/gallium-based garnets have great potential as host scintillators for medical imaging applications. (Gd,Lu)3(Al,Ga)5O12:Ce and denoted as GLuGAG feature high effective atomic number and good light yield, which make it particularly attractive for Positron Emission Tomography (PET) and other γ-ray detection applications. For PET application, rapid decay and good timing resolution are extremely important. Most Ce-doped mixed garnet materials such as GLuGAG:Ce, have their main decay component at around 80 ns. However, it has been reported that the decays of some single crystal scintillators (e.g., LSO and GGAG) can be effectively accelerated by codoping with selected additives such as Ca, Mg and B. In this study, transparent polycrystalline (Gd,Lu)3(Al,Ga)5O12:Ce ceramics codoped with Ca or Mg or additional Ce, were fabricated by the sinter-HIP approach. It was found the transmission of the ceramics are closely related to the microstructure of the ceramics. As the co-dopant levels increase, 2nd phase occurs in the ceramic and thus transparency of the ceramic decreases. Ca and Mg co-doping in GLuGAG:Ce ceramic effectively accelerate decays of GLuGAG:Ce ceramics at a cost of light output. However, additional Ce doping in the GLuGAG:Ce has no benefit on improving decay time but, on the other hand, reduces transmission, light output. The mechanism under the different scintillation behaviors with Mg, Ca and Ce dopants are discussed. The results suggest that decay time of GLuGAG:Ce ceramics can be effectively tailored by co-doping GLuGAG:Ce ceramic with Mg and Ca for applications with optimal timing resolution.

3D Compressed Sensing for Highly Accelerated Hyperpolarized 13C MRSI With In Vivo Applications to Transgenic Mouse Models of Cancer

PubMed Central

Hu, Simon; Lustig, Michael; Balakrishnan, Asha; Larson, Peder E. Z.; Bok, Robert; Kurhanewicz, John; Nelson, Sarah J.; Goga, Andrei; Pauly, John M.; Vigneron, Daniel B.

2010-01-01

High polarization of nuclear spins in liquid state through hyperpolarized technology utilizing dynamic nuclear polarization has enabled the direct monitoring of 13C metabolites in vivo at a high signal-to-noise ratio. Acquisition time limitations due to T1 decay of the hyperpolarized signal require accelerated imaging methods, such as compressed sensing, for optimal speed and spatial coverage. In this paper, the design and testing of a new echo-planar 13C three-dimensional magnetic resonance spectroscopic imaging (MRSI) compressed sensing sequence is presented. The sequence provides up to a factor of 7.53 in acceleration with minimal reconstruction artifacts. The key to the design is employing x and y gradient blips during a fly-back readout to pseudorandomly undersample kf-kx-ky space. The design was validated in simulations and phantom experiments where the limits of undersampling and the effects of noise on the compressed sensing nonlinear reconstruction were tested. Finally, this new pulse sequence was applied in vivo in preclinical studies involving transgenic prostate cancer and transgenic liver cancer murine models to obtain much higher spatial and temporal resolution than possible with conventional echo-planar spectroscopic imaging methods. PMID:20017160

Signatures of particle acceleration at SN 1987A

NASA Technical Reports Server (NTRS)

Gaisser, T. K.; Stanev, Todor; Harding, Alice K.

1989-01-01

At least eight experiments are currently monitoring SN 1987A for photons or neutrinos with energies in the TeV range or higher. Observation of such signals would indicate that the supernova is the site of acceleration of charged particles to even higher energies. The way that the acceleration might occur is discussed, and the prospects for detection of such signals in light of current limits on power in the supernova from sources other than the nickel-cobalt-iron decay chain are evaluated. It is pointed out that signals of particle acceleration may show up in continuum MeV gamma rays as well as in the 100 MeV range.

Simultaneous analysis of neutrinoless double beta decay and LHC pp-cross sections: limits on the left-right mixing angle

NASA Astrophysics Data System (ADS)

Civitarese, O.; Suhonen, J.; Zuber, K.

2015-09-01

The extension of the Standard Model of electroweak interactions, to accommodate massive neutrinos and/or right-handed currents, is one of the fundamental questions to answer in the cross-field of particle and nuclear physics. The consequences of such extensions would reflect upon nuclear decays, like the very exotic nuclear double-beta-decay, as well as upon high-energy proton-proton reactions of the type performed at the LHC accelerator. In this talk we shall address this question by looking at the results reported by the ATLAS and CMS collaborations, where the excitation and decay of a heavy-mass boson may be mediated by a heavy-mass neutrino in proton-proton reactions leading to two jets and two leptons, and by extracting limits on the left-right mixing, from the latest measurements of nuclear-double-beta decays reported by the GERDA and EXO collaborations.

Observation of CP violation in neutral B meson going to positive kaon-antipion and neutral B meson going to pion-antipion decays with the BABAR detector

NASA Astrophysics Data System (ADS)

Li, Xuanzhong

This dissertation describes the measurement of asymmetries in neutral B meson decays to two-body final states of charged pions and kaons. The results are obtained from a data sample of 383 million Upsilon(4 S) → BB¯ decays collected between 1999 and 2006 with the BABAR detector at the PEP-II asymmetric-energy B factory located at the Stanford Linear Accelerator Center, California. The maximum likelihood fit that incorporates kinematical, event-shape, and particle identification information is used to measure the CP asymmetries in B0 → pi +pi- and K+/- pi∓ decays. The direct CP-violating asymmetry between decays to K-pi + is AKpi = -0.107 +/- 0.018+0.007-0.004 . The time-dependent CP-violating parameters in B0 → pi+pi- decays are Spipi = -0.60 +/- 0.11 +/- 0.03, Cpipi = -0.21 +/- 0.09 +/- 0.02. For all the measurements above, the first error is statistical and the second is systematic.

Complement in Lupus Nephritis: New Perspectives.

PubMed

Bao, Lihua; Cunningham, Patrick N; Quigg, Richard J

2015-09-01

Systemic lupus erythematosus (SLE) is an autoimmune disorder caused by loss of tolerance to self-antigens, the production of autoantibodies and deposition of complement-fixing immune complexes (ICs) in injured tissues. SLE is characterized by a wide range of clinical manifestations and targeted organs, with lupus nephritis being one of the most serious complications. The complement system consists of three pathways and is tightly controlled by a set of regulatory proteins to prevent injudicious complement activation on host tissue. The involvement of the complement system in the pathogenesis of SLE is well accepted; yet, its exact role is still not clear. Complement plays dual roles in the pathogenesis of SLE. On the one hand, the complement system appears to have protective features in that hereditary homozygous deficiencies of classical pathway components, such as C1q and C4, are associated with an increased risk for SLE. On the other hand, IC-mediated activation of complement in affected tissues is clearly evident in both experimental and human SLE along with pathological features that are logical consequences of complement activation. Studies in genetically altered mice have shown that lack of complement inhibitors, such as complement factor H (CFH) or decay-accelerating factor (DAF) accelerates the development of experimental lupus nephritis, while treatment with recombinant protein inhibitors, such as Crry-Ig, CR2-Crry, CR2-DAF and CR2-CFH, ameliorates the disease development. Complement-targeted drugs, including soluble complement receptor 1 (TP10), C1 esterase inhibitor and a monoclonal anti-C5 antibody (eculizumab), have been shown to inhibit complement safely, and are now being investigated in a variety of clinical conditions. SLE is an autoimmune disorder which targets multiple systems. Complement is centrally involved and plays dual roles in the pathogenesis of SLE. Studies from experimental lupus models and clinical trials support the use of complement-targeted therapy in the treatment of SLE.

Simple method for quantifying microbiologically assisted chloramine decay in drinking water.

PubMed

Sathasivan, Arumugam; Fisher, Ian; Kastl, George

2005-07-15

In a chloraminated drinking water distribution system, monochloramine decays due to chemical and microbiological reactions. For modeling and operational control purposes, it is necessary to know the relative contribution of each type of reaction, but there was no method to quantify these contributions separately. A simple method was developed to do so. It compares monochloramine decay rates of processed (0.2 microm filtered or microbiologically inhibited by adding 100 microg of silver/L as silver nitrate) and unprocessed samples under controlled temperature conditions. The term microbial decay factor (Fm) was defined and derived from this method, to characterize the relative contribution of microbiologically assisted monochloramine decay to the total monochloramine decay observed in bulk water. Fm is the ratio between microbiologically assisted monochloramine decay and chemical decay of a given water sample measured at 20 degrees C. One possible use of the method is illustrated, where a service reservoir's bulk and inlet waters were sampled twice and analyzed for both the traditional indicators and the microbial decay factor. The microbial decay factor values alone indicated that more microbiologically assisted monochloramine decay was occurring in one bulk water than the other. In contrast, traditional nitrification indicators failed to show any difference. Further analysis showed that the microbial decay factor is more sensitive and that it alone can provide an early warning.

The Effects of Water Matrix on Decay of Human Fecal Molecular Markers and Campylobacter spp.

EPA Science Inventory

Although molecular source tracking for human fecal contamination is used on a wide range of sample types, little is known about comparative decay of proposed molecular markers under different conditions, or correlation with pathogen decay. Our purpose was to measure correlations ...

A new convergence analysis and perturbation resilience of some accelerated proximal forward-backward algorithms with errors

NASA Astrophysics Data System (ADS)

Reem, Daniel; De Pierro, Alvaro

2017-04-01

Many problems in science and engineering involve, as part of their solution process, the consideration of a separable function which is the sum of two convex functions, one of them possibly non-smooth. Recently a few works have discussed inexact versions of several accelerated proximal methods aiming at solving this minimization problem. This paper shows that inexact versions of a method of Beck and Teboulle (fast iterative shrinkable tresholding algorithm) preserve, in a Hilbert space setting, the same (non-asymptotic) rate of convergence under some assumptions on the decay rate of the error terms The notion of inexactness discussed here seems to be rather simple, but, interestingly, when comparing to related works, closely related decay rates of the errors terms yield closely related convergence rates. The derivation sheds some light on the somewhat mysterious origin of some parameters which appear in various accelerated methods. A consequence of the analysis is that the accelerated method is perturbation resilient, making it suitable, in principle, for the superiorization methodology. By taking this into account, we re-examine the superiorization methodology and significantly extend its scope. This work was supported by FAPESP 2013/19504-9. The second author was supported also by CNPq grant 306030/2014-4.

Knockdown of Myo-Inositol Transporter SMIT1 Normalizes Cholinergic and Glutamatergic Function in an Immortalized Cell Line Established from the Cerebral Cortex of a Trisomy 16 Fetal Mouse, an Animal Model of Human Trisomy 21 (Down Syndrome).

PubMed

Cárdenas, Ana María; Fernández-Olivares, Paola; Díaz-Franulic, Ignacio; González-Jamett, Arlek M; Shimahara, Takeshi; Segura-Aguilar, Juan; Caviedes, Raúl; Caviedes, Pablo

2017-11-01

The Na + /myo-inositol cotransporter (SMIT1) is overexpressed in human Down syndrome (DS) and in trisomy 16 fetal mice (Ts16), an animal model of the human condition. SMIT1 overexpression determines increased levels of intracellular myo-inositol, a precursor of phophoinositide synthesis. SMIT1 is overexpressed in CTb cells, an immortalized cell line established from the cerebral cortex of a Ts16 mouse fetus. CTb cells exhibit impaired cytosolic Ca 2+ signals in response to glutamatergic and cholinergic stimuli (increased amplitude and delayed time-dependent kinetics in the decay post-stimulation), compared to our CNh cell line, derived from the cerebral cortex of a euploid animal. Considering the role of myo-inositol in intracellular signaling, we normalized SMIT1 expression in CTb cells using specific mRNA antisenses. Forty-eight hours post-transfection, SMIT1 levels in CTb cells reached values comparable to those of CNh cells. At this time, decay kinetics of Ca 2+ signals induced by either glutamate, nicotine, or muscarine were accelerated in transfected CTb cells, to values similar to those of CNh cells. The amplitude of glutamate-induced cytosolic Ca 2+ signals in CTb cells was also normalized. The results suggest that SMIT1 overexpression contributes to abnormal cholinergic and glutamatergic Ca 2+ signals in the trisomic condition, and knockdown of DS-related genes in our Ts16-derived cell line could constitute a relevant tool to study DS-related neuronal dysfunction.

Compartmentalized human immunodeficiency virus type 1 originates from long-lived cells in some subjects with HIV-1-associated dementia.

PubMed

Schnell, Gretja; Spudich, Serena; Harrington, Patrick; Price, Richard W; Swanstrom, Ronald

2009-04-01

Human immunodeficiency virus type 1 (HIV-1) invades the central nervous system (CNS) shortly after systemic infection and can result in the subsequent development of HIV-1-associated dementia (HAD) in a subset of infected individuals. Genetically compartmentalized virus in the CNS is associated with HAD, suggesting autonomous viral replication as a factor in the disease process. We examined the source of compartmentalized HIV-1 in the CNS of subjects with HIV-1-associated neurological disease and in asymptomatic subjects who were initiating antiretroviral therapy. The heteroduplex tracking assay (HTA), targeting the variable regions of env, was used to determine which HIV-1 genetic variants in the cerebrospinal fluid (CSF) were compartmentalized and which variants were shared with the blood plasma. We then measured the viral decay kinetics of individual variants after the initiation of antiretroviral therapy. Compartmentalized HIV-1 variants in the CSF of asymptomatic subjects decayed rapidly after the initiation of antiretroviral therapy, with a mean half-life of 1.57 days. Rapid viral decay was also measured for CSF-compartmentalized variants in four HAD subjects (t(1/2) mean = 2.27 days). However, slow viral decay was measured for CSF-compartmentalized variants from an additional four subjects with neurological disease (t(1/2) range = 9.85 days to no initial decay). The slow decay detected for CSF-compartmentalized variants was not associated with poor CNS drug penetration, drug resistant virus in the CSF, or the presence of X4 virus genotypes. We found that the slow decay measured for CSF-compartmentalized variants in subjects with neurological disease was correlated with low peripheral CD4 cell count and reduced CSF pleocytosis. We propose a model in which infiltrating macrophages replace CD4(+) T cells as the primary source of productive viral replication in the CNS to maintain high viral loads in the CSF in a substantial subset of subjects with HAD.

Compartmentalized Human Immunodeficiency Virus Type 1 Originates from Long-Lived Cells in Some Subjects with HIV-1–Associated Dementia

PubMed Central

Schnell, Gretja; Spudich, Serena; Harrington, Patrick; Price, Richard W.; Swanstrom, Ronald

2009-01-01

Human immunodeficiency virus type 1 (HIV-1) invades the central nervous system (CNS) shortly after systemic infection and can result in the subsequent development of HIV-1–associated dementia (HAD) in a subset of infected individuals. Genetically compartmentalized virus in the CNS is associated with HAD, suggesting autonomous viral replication as a factor in the disease process. We examined the source of compartmentalized HIV-1 in the CNS of subjects with HIV-1–associated neurological disease and in asymptomatic subjects who were initiating antiretroviral therapy. The heteroduplex tracking assay (HTA), targeting the variable regions of env, was used to determine which HIV-1 genetic variants in the cerebrospinal fluid (CSF) were compartmentalized and which variants were shared with the blood plasma. We then measured the viral decay kinetics of individual variants after the initiation of antiretroviral therapy. Compartmentalized HIV-1 variants in the CSF of asymptomatic subjects decayed rapidly after the initiation of antiretroviral therapy, with a mean half-life of 1.57 days. Rapid viral decay was also measured for CSF-compartmentalized variants in four HAD subjects (t1/2 mean = 2.27 days). However, slow viral decay was measured for CSF-compartmentalized variants from an additional four subjects with neurological disease (t1/2 range = 9.85 days to no initial decay). The slow decay detected for CSF-compartmentalized variants was not associated with poor CNS drug penetration, drug resistant virus in the CSF, or the presence of X4 virus genotypes. We found that the slow decay measured for CSF-compartmentalized variants in subjects with neurological disease was correlated with low peripheral CD4 cell count and reduced CSF pleocytosis. We propose a model in which infiltrating macrophages replace CD4+ T cells as the primary source of productive viral replication in the CNS to maintain high viral loads in the CSF in a substantial subset of subjects with HAD. PMID:19390619

Development of a Quasi-monoenergetic 6 MeV Gamma Facility at NASA Goddard Space Flight Center

NASA Technical Reports Server (NTRS)

Nowicki, Suzanne F.; Hunter, Stanley D.; Parsons, Ann M.

2012-01-01

The 6 MeV Gamma Facility has been developed at NASA Goddard Space Flight Center (GSFC) to allow in-house characterization and testing of a wide range of gamma-ray instruments such as pixelated CdZnTe detectors for planetary science and Compton and pair-production imaging telescopes for astrophysics. The 6 MeV Gamma Facility utilizes a circulating flow of water irradiated by 14 MeV neutrons to produce gamma rays via neutron capture on oxygen (O-16(n,p)N-16 yields O-16* yields O-16 + gamma). The facility provides a low cost, in-house source of 2.742, 6.129 and 7.117 MeV gamma rays, near the lower energy range of most accelerators and well above the 2.614 MeV line from the Th-228 decay chain, the highest energy gamma ray available from a natural radionuclide. The 7.13 s half-life of the N-16 decay allows the water to be irradiated on one side of a large granite block and pumped to the opposite side to decay. Separating the irradiation and decay regions allows for shielding material, the granite block, to be placed between them, thus reducing the low-energy gamma-ray continuum. Comparison between high purity germanium (HPGe) spectra from the facility and a manufactured source, Pu-238/C-13, shows that the low-energy continuum from the facility is reduced by a factor approx. 30 and the gamma-ray rate is approx.100 times higher at 6.129 MeV.

Magnetization transfer studies of the fast and slow tissue water diffusion components in the human brain.

PubMed

Mulkern, Robert V; Vajapeyam, Sridhar; Haker, Steven J; Maier, Stephan E

2005-05-01

Magnetization transfer (MT) properties of the fast and slow diffusion components recently observed in the human brain were assessed experimentally. One set of experiments, performed at 1.5 T in healthy volunteers, was designed to determine whether the amplitudes of fast and slow diffusion components, differentiated on the basis of biexponential fits to signal decays over a wide range of b-factors, demonstrated a different or similar magnetization transfer ratio (MTR). Another set of experiments, performed at 3 T in healthy volunteers, was designed to determine whether MTRs differed when measured from high signal-to-noise images acquired with b-factor weightings of 350 vs 3500 s/mm2. The 3 T studies included measurements of MTR as a function of off-resonance frequency for the MT pulse at both low and high b-factors. The primary conclusion drawn from all the studies is that there appears to be no significant difference between the magnetization transfer properties of the fast and slow tissue water diffusion components. The conclusions do not lend support to a direct interpretation of the 'components' of the biexponential diffusion decay in terms of the 'compartments' associated with intra- and extracellular water. Copyright 2004 John Wiley & Sons, Ltd.

Secondary Neutron Production from Space Radiation Interactions: Advances in Model and Experimental Data Base Development

NASA Technical Reports Server (NTRS)

Heilbronn, Lawrence H.; Townsend, Lawrence W.; Braley, G. Scott; Iwata, Yoshiyuki; Iwase, Hiroshi; Nakamura, Takashi; Ronningen, Reginald M.; Cucinotta, Francis A.

2003-01-01

For humans engaged in long-duration missions in deep space or near-Earth orbit, the risk from exposure to galactic and solar cosmic rays is an important factor in the design of spacecraft, spacesuits, and planetary bases. As cosmic rays are transported through shielding materials and human tissue components, a secondary radiation field is produced. Neutrons are an important component of that secondary field, especially in thickly-shielded environments. Calculations predict that 50% of the dose-equivalent in a lunar or Martian base comes from neutrons, and a recent workshop held at the Johnson Space Center concluded that as much as 30% of the dose in the International Space Station may come from secondary neutrons. Accelerator facilities provide a means for measuring the effectiveness of various materials in their ability to limit neutron production, using beams and energies that are present in cosmic radiation. The nearly limitless range of beams, energies, and target materials that are present in space, however, means that accelerator-based experiments will not provide a complete database of cross sections and thick-target yields that are necessary to plan and design long-duration missions. As such, accurate nuclear models of neutron production are needed, as well as data sets that can be used to compare with, and verify, the predictions from such models. Improvements in a model of secondary neutron production from heavy-ion interactions are presented here, along with the results from recent accelerator-based measurements of neutron-production cross sections. An analytical knockout-ablation model capable of predicting neutron production from high-energy hadron-hadron interactions (both nucleon-nucleus and nucleus-nucleus collisions) has been previously developed. In the knockout stage, the collision between two nuclei result in the emission of one or more nucleons from the projectile and/or target. The resulting projectile and target remnants, referred to as prefragments, then decay by the emission of nucleons, composites, and gamma rays. Recent improvements to the model have incorporated coalescence effects, which effectively tie up single nucleons in the formation of composites during final-state interactions. Comparison of the improved model s predictions with neutron production data near 0 deg in the CA-40+ H reaction at 357 and 565 MeV/nucleon show marked improvement.

Joint Spatial-Spectral Reconstruction and k-t Spirals for Accelerated 2D Spatial/1D Spectral Imaging of 13C Dynamics

PubMed Central

Gordon, Jeremy W.; Niles, David J.; Fain, Sean B.; Johnson, Kevin M.

2014-01-01

Purpose To develop a novel imaging technique to reduce the number of excitations and required scan time for hyperpolarized 13C imaging. Methods A least-squares based optimization and reconstruction is developed to simultaneously solve for both spatial and spectral encoding. By jointly solving both domains, spectral imaging can potentially be performed with a spatially oversampled single echo spiral acquisition. Digital simulations, phantom experiments, and initial in vivo hyperpolarized [1-13C]pyruvate experiments were performed to assess the performance of the algorithm as compared to a multi-echo approach. Results Simulations and phantom data indicate that accurate single echo imaging is possible when coupled with oversampling factors greater than six (corresponding to a worst case of pyruvate to metabolite ratio < 9%), even in situations of substantial T2* decay and B0 heterogeneity. With lower oversampling rates, two echoes are required for similar accuracy. These results were confirmed with in vivo data experiments, showing accurate single echo spectral imaging with an oversampling factor of 7 and two echo imaging with an oversampling factor of 4. Conclusion The proposed k-t approach increases data acquisition efficiency by reducing the number of echoes required to generate spectroscopic images, thereby allowing accelerated acquisition speed, preserved polarization, and/or improved temporal or spatial resolution. Magn Reson Med PMID:23716402

Polarization in Vector-Vector Decay of B Mesons at CDF

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hans, Randal Milton

1996-01-01

The factorization assumption in bound state decays (splitting four-quark operators into the product of two two-quark operators) has proved to be a useful tool in B and D meson decays. The longitudinal polarization fraction,more » $,L/,,$ in the decays $$B_d \\to J/\\psi K^{*0}$$ and $$B_s \\to J/\\psi \\phi$$ can be calculated using various phenomenological models within the factorization assumption and, when compared to experimental measurements, provides a test of the factorization procedure when extended to color suppressed B decays....« less

Pion-decay radiation and two-phase acceleration in the June 3, 1982 solar flare

NASA Technical Reports Server (NTRS)

Ramaty, R.; Dermer, C. D.; Murphy, R. J.

1986-01-01

The June 3, 1982 flare is unique in the wealth of observed neutron, gamma-ray and energetic-particle emission that it produced. Using calculations of high-energy emissions to fit the various time-dependent gamma-ray fluxes, a self-consistent interaction model for the June 3 flare is constructed in which the observed fluxes are produced by two distinct particle populations with different acceleration and interaction time histories as well as different but time-independent energy spectra. The two populations are associated with first- and second-phase particle acceleration, respectively.

a High-Precision Branching-Ratio Measurement for the Superallowed β+ Emitter 74Rb

NASA Astrophysics Data System (ADS)

Dunlop, R.; Chagnon-Lessard, S.; Finlay, P.; Garrett, P. E.; Hadinia, B.; Leach, K. G.; Svensson, C. E.; Wong, J.; Ball, G.; Garnsworthy, A. B.; Glister, J.; Hackman, G.; Tardiff, E. R.; Triambak, S.; Williams, S. J.; Leslie, J. R.; Andreoiu, C.; Chester, A.; Cross, D.; Starosta, K.; Yates, S. W.; Zganjar, E. F.

2013-03-01

Precision measurements of superallowed Fermi beta decay allow for tests of the Cabibbo-Kobayashi-Maskawa matrix (CKM) unitarity, the conserved vector current hypothesis, and the magnitude of isospin-symmetry-breaking effects in nuclei. A high-precision measurement of the branching ratio for the β+ decay of 74Rb has been performed at the Isotope Separator and ACcelerator (ISAC) facility at TRIUMF. The 8π spectrometer, an array of 20 close-packed HPGe detectors, was used to detect gamma rays emitted following the decay of 74Rb. PACES, an array of 5 Si(Li) detectors, was used to detect emitted conversion electrons, while SCEPTAR, an array of plastic scintillators, was used to detect emitted beta particles. A total of 51γ rays have been identified following the decay of 21 excited states in the daughter nucleus 74Kr.

Black-hole production at LHC: Special features, problems, and expectations

DOE Office of Scientific and Technical Information (OSTI.GOV)

Savina, M. V., E-mail: savina@cern.ch

2011-03-15

A brief survey of the present-day status of the problem of multidimensional-black-hole production at accelerators according to models featuring large extra dimensions is given. The respective production cross section and the Hawking temperature and decay rate are estimated versus model parameters. Possible flaws and assumptions whose accurate inclusion can reduce significantly the probability of blackhole production at accelerators in relation to earlier optimistic estimates are also discussed.

Applications of High Intensity Proton Accelerators

NASA Astrophysics Data System (ADS)

Raja, Rajendran; Mishra, Shekhar

2010-06-01

Superconducting radiofrequency linac development at Fermilab / S. D. Holmes -- Rare muon decay experiments / Y. Kuno -- Rare kaon decays / D. Bryman -- Muon collider / R. B. Palmer -- Neutrino factories / S. Geer -- ADS and its potential / J.-P. Revol -- ADS history in the USA / R. L. Sheffield and E. J. Pitcher -- Accelerator driven transmutation of waste: high power accelerator for the European ADS demonstrator / J. L. Biarrotte and T. Junquera -- Myrrha, technology development for the realisation of ADS in EU: current status & prospects for realisation / R. Fernandez ... [et al.] -- High intensity proton beam production with cyclotrons / J. Grillenberger and M. Seidel -- FFAG for high intensity proton accelerator / Y. Mori -- Kaon yields for 2 to 8 GeV proton beams / K. K. Gudima, N. V. Mokhov and S. I. Striganov -- Pion yield studies for proton driver beams of 2-8 GeV kinetic energy for stopped muon and low-energy muon decay experiments / S. I. Striganov -- J-Parc accelerator status and future plans / H. Kobayashi -- Simulation and verification of DPA in materials / N. V. Mokhov, I. L. Rakhno and S. I. Striganov -- Performance and operational experience of the CNGS facility / E. Gschwendtner -- Particle physics enabled with super-conducting RF technology - summary of working group 1 / D. Jaffe and R. Tschirhart -- Proton beam requirements for a neutrino factory and muon collider / M. S. Zisman -- Proton bunching options / R. B. Palmer -- CW SRF H linac as a proton driver for muon colliders and neutrino factories / M. Popovic, C. M. Ankenbrandt and R. P. Johnson -- Rapid cycling synchrotron option for Project X / W. Chou -- Linac-based proton driver for a neutrino factory / R. Garoby ... [et al.] -- Pion production for neutrino factories and muon colliders / N. V. Mokhov ... [et al.] -- Proton bunch compression strategies / V. Lebedev -- Accelerator test facility for muon collider and neutrino factory R&D / V. Shiltsev -- The superconducting RF linac for muon collider and neutrino factory - summary of working group 2 / J. Galambos, R. Garoby and S. Geer -- Prospects for a very high power CW SRF linac / R. A. Rimmer -- Indian accelerator program for ADS applications / V. C. Sahni and P. Singh -- Ion accelerator activities at VECC (particularly, operating at low temperature) / R. K. Bhandari -- Chinese efforts in high intensity proton accelerators / S. Fu, J. Wang and S. Fang -- ADSR activity in the UK / R. J. Barlow -- ADS development in Japan / K. Kikuchi -- Project-X, SRF, and very large power stations / C. M. Ankenbrandt, R. P. Johnson and M. Popovic -- Power production and ADS / R. Raja -- Experimental neutron source facility based on accelerator driven system / Y. Gohar -- Transmutation mission / W. S. Yang -- Safety performance and issues / J. E. Cahalan -- Spallation target design for accelerator-driven systems / Y. Gohar -- Design considerations for accelerator transmutation of waste system / W. S. Yang -- Japan ADS program / T. Sasa -- Overview of members states' and IAEA activities in the field of Accelerator Driven Systems (ADS) / A. Stanculescu -- Linac for ADS applications - accelerator technologies / R. W. Garnett and R. L. Sheffield -- SRF linacs and accelerator driven sub-critical systems - summary working groups 3 & 4 / J. Delayen -- Production of Actinium-225 via high energy proton induced spallation of Thorium-232 / J. Harvey ... [et al.] -- Search for the electric dipole moment of Radium-225 / R. J. Holt, Z.-T. Lu and R. Mueller -- SRF linac and material science and medicine - summary of working group 5 / J. Nolen, E. Pitcher and H. Kirk.

Erasing the face after-effect.

PubMed

Kiani, Ghazaleh; Davies-Thompson, Jodie; Barton, Jason J S

2014-10-24

Perceptual after-effects decay over time at a rate that depends on several factors, such as the duration of adaptation and the duration of the test stimuli. Whether this decay is accelerated by exposure to other faces after adaptation is not known. Our goal was to determine if the appearance of other faces during a delay period after adaptation affected the face identity after-effect. In the first experiment we investigated whether, in the perception of ambiguous stimuli created by morphing between two faces, the repulsive after-effects from adaptation to one face were reduced by brief presentation of the second face in a delay period. We found no effect; however, this may have been confounded by a small attractive after-effect from the interference face. In the second experiment, the interference stimuli were faces unrelated to those used as adaptation stimuli, and we examined after-effects at three different delay periods. This showed a decline in after-effects as the time since adaptation increased, and an enhancement of this decline by the presentation of intervening faces. An exponential model estimated that the intervening faces caused an 85% reduction in the time constant of the after-effect decay. In conclusion, we confirm that face after-effects decline rapidly after adaptation and that exposure to other faces hastens the re-setting of the system. Crown Copyright © 2014. Published by Elsevier B.V. All rights reserved.

Accurate Attitude Estimation Using ARS under Conditions of Vehicle Movement Based on Disturbance Acceleration Adaptive Estimation and Correction

PubMed Central

Xing, Li; Hang, Yijun; Xiong, Zhi; Liu, Jianye; Wan, Zhong

2016-01-01

This paper describes a disturbance acceleration adaptive estimate and correction approach for an attitude reference system (ARS) so as to improve the attitude estimate precision under vehicle movement conditions. The proposed approach depends on a Kalman filter, where the attitude error, the gyroscope zero offset error and the disturbance acceleration error are estimated. By switching the filter decay coefficient of the disturbance acceleration model in different acceleration modes, the disturbance acceleration is adaptively estimated and corrected, and then the attitude estimate precision is improved. The filter was tested in three different disturbance acceleration modes (non-acceleration, vibration-acceleration and sustained-acceleration mode, respectively) by digital simulation. Moreover, the proposed approach was tested in a kinematic vehicle experiment as well. Using the designed simulations and kinematic vehicle experiments, it has been shown that the disturbance acceleration of each mode can be accurately estimated and corrected. Moreover, compared with the complementary filter, the experimental results have explicitly demonstrated the proposed approach further improves the attitude estimate precision under vehicle movement conditions. PMID:27754469

Accurate Attitude Estimation Using ARS under Conditions of Vehicle Movement Based on Disturbance Acceleration Adaptive Estimation and Correction.

PubMed

Xing, Li; Hang, Yijun; Xiong, Zhi; Liu, Jianye; Wan, Zhong

2016-10-16

This paper describes a disturbance acceleration adaptive estimate and correction approach for an attitude reference system (ARS) so as to improve the attitude estimate precision under vehicle movement conditions. The proposed approach depends on a Kalman filter, where the attitude error, the gyroscope zero offset error and the disturbance acceleration error are estimated. By switching the filter decay coefficient of the disturbance acceleration model in different acceleration modes, the disturbance acceleration is adaptively estimated and corrected, and then the attitude estimate precision is improved. The filter was tested in three different disturbance acceleration modes (non-acceleration, vibration-acceleration and sustained-acceleration mode, respectively) by digital simulation. Moreover, the proposed approach was tested in a kinematic vehicle experiment as well. Using the designed simulations and kinematic vehicle experiments, it has been shown that the disturbance acceleration of each mode can be accurately estimated and corrected. Moreover, compared with the complementary filter, the experimental results have explicitly demonstrated the proposed approach further improves the attitude estimate precision under vehicle movement conditions.

Relativistic neutrons in active galactic nuclei

NASA Technical Reports Server (NTRS)

Sikora, Marek; Begelman, Mitchell C.; Rudak, Bronislaw

1989-01-01

The acceleration of protons to relativistic energies in active galactic nuclei leads to the creation of relativistic neutrons which escape from the central engine. The neutrons decay at distances of up to 1-100 pc, depositing their energies and momenta in situ. Energy deposition by decaying neutrons may inhibit spherical accretion and drive a wind, which could be responsible for the velocity fields in emission-line regions and the outflow of broad absorption line systems. Enhanced pressure in the neutron decay region may also help to confine emission line clouds. A fraction of the relativistic proton energy is radiated in gamma-rays with energies which may be as large as about 100,000 GeV.

Alkali earth co-doping effects on luminescence and scintillation properties of Ce doped Gd3Al2Ga3O12 scintillator

NASA Astrophysics Data System (ADS)

Kamada, Kei; Nikl, Martin; Kurosawa, Shunsuke; Beitlerova, Alena; Nagura, Aya; Shoji, Yasuhiro; Pejchal, Jan; Ohashi, Yuji; Yokota, Yuui; Yoshikawa, Akira

2015-03-01

The Mg and Ca co-doped Ce:Gd3Al2Ga3O12 single crystals were prepared by micro pulling down method with a wide concentration range 0-1000 ppm of the codopants. Absorption and luminescence spectra were measured together with several other scintillation characteristics, namely the scintillation decay and light yield to reveal the effect of Mg and Ca co-doping. The scintillation decays were accelerated by both Mg and Ca codopants. Comparing to Ca co-doping, the Mg co-doped samples showed much faster decay and comparatively smaller light output decrease with increasing Mg dopant concentration.

Xylan-regulated delivery of human keratinocyte growth factor-2 to the inflamed colon by the human anaerobic commensal bacterium Bacteroides ovatus.

PubMed

Hamady, Zaed Z R; Scott, Nigel; Farrar, Mark D; Lodge, J Peter A; Holland, Keith T; Whitehead, Terence; Carding, Simon R

2010-04-01

Human growth factors are potential therapeutic agents for various inflammatory disorders affecting the gastrointestinal tract. However, they are unstable when administered orally and systemic administration requires high doses increasing the risk of unwanted side effects. Live microorganism-based delivery systems can overcome these problems although they suffer from the inability to control heterologous protein production and there are concerns regarding biosafety and environmental contamination. To overcome these limitations we have developed a new live bacteria drug-delivery system using the human commensal gut bacterium Bacteroides ovatus engineered to secrete human growth factors in response to dietary xylan. The anaerobic nature of B ovatus provides an inherent biosafety feature. B ovatus strains expressing human keratinocyte growth factor-2, which plays a central role in intestinal epithelial homeostasis and repair (BO-KGF), were generated by homologous recombination and evaluated using the dextran sodium sulfate (DSS)-induced model of intestinal epithelial injury and colitis. In response to xylan BO-KGF produced biologically active KGF both in vitro and in vivo. In DSS treated mice administration of xylan and BO-KGF had a significant therapeutic effect in reducing weight loss, improving stool consistency, reducing rectal bleeding, accelerating healing of damaged epithelium, reducing inflammation and neutrophil infiltration, reducing expression of pro-inflammatory cytokines, and accelerating production of goblet cells. BO-KGF and xylan treatment also had a marked prophylactic effect limiting the development of inflammation and disruption of the epithelial barrier. This novel, diet-regulated, live bacterial drug delivery system may be applicable to treating various bowel disorders.

Persistence of dead-cell bacterial DNA in ex vivo root canals and influence of nucleases on DNA decay in vitro.

PubMed

Brundin, Malin; Figdor, David; Roth, Chrissie; Davies, John K; Sundqvist, Göran; Sjögren, Ulf

2010-12-01

The fate of DNA from bacteria that do not survive in the root canal is uncertain, yet DNA longevity may confound recovery of authentic etiologic participants in the disease process. This study assessed the recovery of PCR-detectable DNA in ex vivo human root canals and some environmental factors on the decay of microbial DNA. Heat-killed Enterococcus faecalis cells were inoculated into instrumented human root canals ex vivo, and samples were taken at intervals over 2 years and analyzed by polymerase chain reaction. In an in vitro assay, heat-killed E. faecalis cells and extracted E. faecalis DNA were inoculated into various media, DNase, and culture of a DNase-producing species, Prevotella intermedia. Recovery of DNA was assessed by gel electrophoresis. In ex vivo human teeth, amplifiable DNA was recovered after 1 and 2 years (in 14/15 and 21/25 teeth, respectively). In vitro experiments showed that extracted DNA incubated in different media (water, 10%-50% sera, and DNase) progressively decomposed to levels below the detection limit. In corresponding assays, cell-bound DNA was more resistant to decay. Amplifiable DNA is preserved after cell death, but the critical determinant is the form of DNA. Free DNA undergoes spontaneous and enzymatic decomposition, whereas cell-bound E. faecalis DNA persists for long periods. Copyright © 2010 Mosby, Inc. All rights reserved.

Extended hybrid-space SENSE for EPI: Off-resonance and eddy current corrected joint interleaved blip-up/down reconstruction.

PubMed

Zahneisen, Benjamin; Aksoy, Murat; Maclaren, Julian; Wuerslin, Christian; Bammer, Roland

2017-06-01

Geometric distortions along the phase encode direction caused by off-resonant spins are still a major issue in EPI based functional and diffusion imaging. If the off-resonance map is known it is possible to correct for distortions. Most correction methods operate as a post-processing step on the reconstructed magnitude images. Here, we present an algebraic reconstruction method (hybrid-space SENSE) that incorporates a physics based model of off-resonances, phase inconsistencies between k-space segments, and T2*-decay during the acquisition. The method can be used to perform a joint reconstruction of interleaved acquisitions with normal (blip-up) and inverted (blip-down) phase encode direction which results in reduced g-factor penalty. A joint blip-up/down simultaneous multi slice (SMS) reconstruction for SMS-factor 4 in combination with twofold in-plane acceleration leads to a factor of two decrease in maximum g-factor penalty while providing off-resonance and eddy-current corrected images. We provide an algebraic framework for reconstructing diffusion weighted EPI data that in addition to the general applicability of hybrid-space SENSE to 2D-EPI, SMS-EPI and 3D-EPI with arbitrary k-space coverage along z, allows for a modeling of arbitrary spatio-temporal effects during the acquisition period like off-resonances, phase inconsistencies and T2*-decay. The most immediate benefit is a reduction in g-factor penalty if an interleaved blip-up/down acquisition strategy is chosen which facilitates eddy current estimation and ensures no loss in k-space encoding in regions with strong off-resonance gradients. Copyright © 2017 Elsevier Inc. All rights reserved.

On the reduced lifetime of nitrous oxide due to climate change induced acceleration of the Brewer-Dobson circulation as simulated by the MPI Earth System Model

NASA Astrophysics Data System (ADS)

Kracher, D.; Manzini, E.; Reick, C. H.; Schultz, M. G.; Stein, O.

2014-12-01

Greenhouse gas induced climate change will modify the physical conditions of the atmosphere. One of the projected changes is an acceleration of the Brewer-Dobson circulation in the stratosphere, as it has been shown in many model studies. This change in the stratospheric circulation consequently bears an effect on the transport and distribution of atmospheric components such as N2O. Since N2O is involved in ozone destruction, a modified distribution of N2O can be of importance for ozone chemistry. N2O is inert in the troposphere and decays only in the stratosphere. Thus, changes in the exchange between troposphere and stratosphere can also affect the stratospheric sink of N2O, and consequently its atmospheric lifetime. N2O is a potent greenhouse gas with a global warming potential of currently approximately 300 CO2-equivalents in a 100-year perspective. A faster decay in atmospheric N2O mixing ratios, i.e. a decreased atmospheric lifetime of N2O, will also reduce its global warming potential. In order to assess the impact of climate change on atmospheric circulation and implied effects on the distribution and lifetime of atmospheric N2O, we apply the Max Planck Institute Earth System Model, MPI-ESM. MPI-ESM consists of the atmospheric general circulation model ECHAM, the land surface model JSBACH, and MPIOM/HAMOCC representing ocean circulation and ocean biogeochemistry. Prognostic atmospheric N2O concentrations in MPI-ESM are determined by land N2O emissions, ocean-atmosphere N2O exchange and atmospheric tracer transport. As stratospheric chemistry is not explicitly represented in MPI-ESM, stratospheric decay rates of N2O are prescribed from a MACC MOZART simulation. Increasing surface temperatures and CO2 concentrations in the stratosphere impact atmospheric circulation differently. Thus, we conduct a series of transient runs with the atmospheric model of MPI-ESM to isolate different factors governing a shift in atmospheric circulation. From those transient simulations we diagnose decreasing tropospheric N2O concentrations, increased transport of N2O from the troposphere to the stratosphere, and increasing stratospheric decay of N2O leading to a reduction in atmospheric lifetime of N2O, in dependency to climate change evolution.

Temperature limits trail following behaviour through pheromone decay in ants

NASA Astrophysics Data System (ADS)

van Oudenhove, Louise; Billoir, Elise; Boulay, Raphaël; Bernstein, Carlos; Cerdá, Xim

2011-12-01

In Mediterranean habitats, temperature affects both ant foraging behaviour and community structure. Many studies have shown that dominant species often forage at lower temperature than subordinates. Yet, the factors that constrain dominant species foraging activity in hot environments are still elusive. We used the dominant ant Tapinoma nigerrimum as a model species to test the hypothesis that high temperatures hinder trail following behaviour by accelerating pheromone degradation. First, field observations showed that high temperatures (> 30°C) reduce the foraging activity of T. nigerrimum independently of the daily and seasonal rhythms of this species. Second, we isolated the effect of high temperatures on pheromone trail efficacy from its effect on worker physiology. A marked substrate was heated during 10 min (five temperature treatments from 25°C to 60°C), cooled down to 25°C, and offered in a test choice to workers. At hot temperature treatments (>40°C), workers did not discriminate the previously marked substrate. High temperatures appeared therefore to accelerate pheromone degradation. Third, we assessed the pheromone decay dynamics by a mechanistic model fitted with Bayesian inference. The model predicted ant choice through the evolution of pheromone concentration on trails as a function of both temperature and time since pheromone deposition. Overall, our results highlighted that the effect of high temperatures on recruitment intensity was partly due to pheromone evaporation. In the Mediterranean ant communities, this might affect dominant species relying on chemical recruitment, more than subordinate ant species, less dependent on chemical communication and less sensitive to high temperatures.

An autonomous structural health monitoring system for Waiau interchange.

DOT National Transportation Integrated Search

2013-03-01

Bridge infrastructure is a critical element of the transportation system which makes maintaining its safety and : performance vital to a healthy society. However, the civil infrastructure systems in the United States are decaying : at an accelerated ...

The Particle Adventure | Accelerators and Particle Detectors

Science.gov Websites

Electromagnetism Residual EM force What about the nucleus? Strong Color charge Quark confinement Quarks emit gluons Decaying to two photons Shortcomings of the first data Is this particle really the Higgs Boson? Does it

An unattended device for high-voltage sampling and passive measurement of thoron decay products.

PubMed

Gierl, Stefanie; Meisenberg, Oliver; Haninger, Thomas; Wielunski, Marek; Tschiersch, Jochen

2014-02-01

An integrating measurement device for the concentration of airborne thoron decay products was designed and calibrated. It is suitable for unattended use over up to several months also in inhabited dwellings. The device consists of a hemispheric capacitor with a wire mesh as the outer electrode on ground potential and the sampling substrates as the inner electrode on +7.0 kV. Negatively charged and neutral thoron decay products are accelerated to and deposited on the sampling substrates. As sampling substrates, CR39 solid-state nuclear track detectors are used in order to record the alpha decay of the sampled decay products. Nuclide discrimination is achieved by covering the detectors with aluminum foil of different thickness, which are penetrated only by alpha particles with sufficient energy. Devices of this type were calibrated against working level monitors in a thoron experimental house. The sensitivity was measured as 9.2 tracks per Bq/m(3) × d of thoron decay products. The devices were used over 8 weeks in several houses built of earthen material in southern Germany, where equilibrium equivalent concentrations of 1.4-9.9 Bq/m(3) of thoron decay products were measured.

HTLV-1 Tax plugs and freezes UPF1 helicase leading to nonsense-mediated mRNA decay inhibition.

PubMed

Fiorini, Francesca; Robin, Jean-Philippe; Kanaan, Joanne; Borowiak, Malgorzata; Croquette, Vincent; Le Hir, Hervé; Jalinot, Pierre; Mocquet, Vincent

2018-01-30

Up-Frameshift Suppressor 1 Homolog (UPF1) is a key factor for nonsense-mediated mRNA decay (NMD), a cellular process that can actively degrade mRNAs. Here, we study NMD inhibition during infection by human T-cell lymphotropic virus type I (HTLV-1) and characterise the influence of the retroviral Tax factor on UPF1 activity. Tax interacts with the central helicase core domain of UPF1 and might plug the RNA channel of UPF1, reducing its affinity for nucleic acids. Furthermore, using a single-molecule approach, we show that the sequential interaction of Tax with a RNA-bound UPF1 freezes UPF1: this latter is less sensitive to the presence of ATP and shows translocation defects, highlighting the importance of this feature for NMD. These mechanistic insights reveal how HTLV-1 hijacks the central component of NMD to ensure expression of its own genome.

Anisotropic Magnetohydrodynamic Turbulence Driven by Parametric Decay Instability: The Onset of Phase Mixing and Alfvén Wave Turbulence

NASA Astrophysics Data System (ADS)

Shoda, Munehito; Yokoyama, Takaaki

2018-06-01

We conduct a 3D magnetohydrodynamic (MHD) simulation of the parametric decay instability of Alfvén waves and resultant compressible MHD turbulence, which is likely to develop in the solar wind acceleration region. Because of the presence of the mean magnetic field, the nonlinear stage is characterized by filament-like structuring and anisotropic cascading. By calculating the timescales of phase mixing and the evolution of Alfvén wave turbulence, we have found that the early nonlinear stage is dominated by phase mixing, while the later phase is dominated by imbalanced Alfvén wave turbulence. Our results indicate that the regions in the solar atmosphere with large density fluctuation, such as the coronal bottom and wind acceleration region, are heated by phase-mixed Alfvén waves, while the other regions are heated by Alfvén wave turbulence.

Cosmology and accelerator tests of strongly interacting dark matter

DOE PAGES

Berlin, Asher; Blinov, Nikita; Gori, Stefania; ...

2018-03-23

A natural possibility for dark matter is that it is composed of the stable pions of a QCD-like hidden sector. Existing literature largely assumes that pion self-interactions alone control the early universe cosmology. We point out that processes involving vector mesons typically dominate the physics of dark matter freeze-out and significantly widen the viable mass range for these models. The vector mesons also give rise to striking signals at accelerators. For example, in most of the cosmologically favored parameter space, the vector mesons are naturally long-lived and produce standard model particles in their decays. Electron and proton beam fixed-target experimentsmore » such as HPS, SeaQuest, and LDMX can exploit these signals to explore much of the viable parameter space. As a result, we also comment on dark matter decay inherent in a large class of previously considered models and explain how to ensure dark matter stability.« less

Cosmology and accelerator tests of strongly interacting dark matter

NASA Astrophysics Data System (ADS)

Berlin, Asher; Blinov, Nikita; Gori, Stefania; Schuster, Philip; Toro, Natalia

2018-03-01

A natural possibility for dark matter is that it is composed of the stable pions of a QCD-like hidden sector. Existing literature largely assumes that pion self-interactions alone control the early universe cosmology. We point out that processes involving vector mesons typically dominate the physics of dark matter freeze-out and significantly widen the viable mass range for these models. The vector mesons also give rise to striking signals at accelerators. For example, in most of the cosmologically favored parameter space, the vector mesons are naturally long-lived and produce standard model particles in their decays. Electron and proton beam fixed-target experiments such as HPS, SeaQuest, and LDMX can exploit these signals to explore much of the viable parameter space. We also comment on dark matter decay inherent in a large class of previously considered models and explain how to ensure dark matter stability.

Cosmology and accelerator tests of strongly interacting dark matter

DOE Office of Scientific and Technical Information (OSTI.GOV)

Berlin, Asher; Blinov, Nikita; Gori, Stefania

A natural possibility for dark matter is that it is composed of the stable pions of a QCD-like hidden sector. Existing literature largely assumes that pion self-interactions alone control the early universe cosmology. We point out that processes involving vector mesons typically dominate the physics of dark matter freeze-out and significantly widen the viable mass range for these models. The vector mesons also give rise to striking signals at accelerators. For example, in most of the cosmologically favored parameter space, the vector mesons are naturally long-lived and produce standard model particles in their decays. Electron and proton beam fixed-target experimentsmore » such as HPS, SeaQuest, and LDMX can exploit these signals to explore much of the viable parameter space. As a result, we also comment on dark matter decay inherent in a large class of previously considered models and explain how to ensure dark matter stability.« less

Spallation processes and nuclear interaction products of cosmic rays.

PubMed

Silberberg, R; Tsao, C H

1990-08-01

Most cosmic-ray nuclei heavier than helium have suffered nuclear collisions in the interstellar gas, with transformation of nuclear composition. The isotopic and elemental composition at the sources has to be inferred from the observed composition near the Earth. The source composition permits tests of current ideas on sites of origin, nucleosynthesis in stars, evolution of stars, the mixing and composition of the interstellar medium and injection processes prior to acceleration. The effects of nuclear spallation, production of radioactive nuclides and the time dependence of their decay provide valuable information on the acceleration and propagation of cosmic rays, their nuclear transformations, and their confinement time in the Galaxy. The formation of spallation products that only decay by electron capture and are relatively long-lived permits an investigation of the nature and density fluctuations (like clouds) of the interstellar medium. Since nuclear collisions yield positrons, antiprotons, gamma rays and neutrinos, we shall discuss these topics briefly.

Generation of anomalously energetic suprathermal electrons by an electron beam interacting with a nonuniform plasma

NASA Astrophysics Data System (ADS)

Sydorenko, Dmytro

2015-11-01

Electrons emitted by electrodes surrounding or immersed in the plasma are accelerated by the sheath electric field and become electron beams penetrating the plasma. In plasma applications where controlling the electron velocity distribution function (EVDF) is crucial, these beams are an important factor capable of modifying the EVDF and affecting the discharge properties. Recently, it was reported that an EVDF measured in a dc-rf discharge with 800 V dc voltage has not only a peak of 800 eV electrons emitted from the dc-biased electrode, but also a peak of suprathermal electrons with energy up to several hundred eV. Initial explanation of the suprathermal peak suggested that the fast long plasma waves excited by the beam decay parametrically into ion acoustic waves and short plasma waves with much lower phase velocity which accelerate bulk electrons to suprathermal energies. Particle-in-cell simulation of a dc beam-plasma system, however, reveals that the short waves appear not due to the parametric instability, but due to the plasma nonuniformity. Moreover, the acceleration may occur in two stages. Plasma waves excited by the beam in the middle of the system propagate towards the anode and enter the density gradient area where their wavelength and phase speed rapidly decrease. Acceleration of thermal electrons by these waves is the first stage. Some of the accelerated electrons reflect from the anode sheath, travel through the plasma, reflect near the cathode, and enter the accelerating area again but with the energy higher than before. The acceleration that occurs now is the second stage. The energy of a particle after the second acceleration exceeds the initial thermal energy by an order of magnitude. This two-stage mechanism plays a role in explaining previous observations of energetic suprathermal electrons in similar discharges. The study is performed in collaboration with I. D. Kaganovich (PPPL), P. L. G. Ventzek and L. Chen (Tokyo Electron America).

The impact of the postharvest environment on the viability and virulence of decay fungi.

PubMed

Liu, Jia; Sui, Yuan; Wisniewski, Michael; Xie, Zhigang; Liu, Yiqing; You, Yuming; Zhang, Xiaojing; Sun, Zhiqiang; Li, Wenhua; Li, Yan; Wang, Qi

2018-07-03

Postharvest decay of fruits, vegetables, and grains by fungal pathogens causes significant economic losses. Infected produce presents a potential health risk since some decay fungi produce mycotoxins that are hazardous to human health. Infections are the result of the interplay between host resistance and pathogen virulence. Both of these processes, however, are significantly impacted by environmental factors, such as temperature, UV, oxidative stress, and water activity. In the present review, the impact of various physical postharvest treatments (e.g., heat and UV) on the viability and virulence of postharvest pathogens is reviewed and discussed. Oxidative injury, protein impairment, and cell wall degradation have all been proposed as the mechanisms by which these abiotic stresses reduce fungal viability and pathogenicity. The response of decay fungi to pH and the ability of pathogens to modulate the pH of the host environment also affect pathogenicity. The effects of the manipulation of the postharvest environment by ethylene, natural edible coatings, and controlled atmosphere storage on fungal viability are also discussed. Lastly, avenues of future research are proposed.

Nonlinear dynamics of beam-plasma instability in a finite magnetic field

NASA Astrophysics Data System (ADS)

Bogdankevich, I. L.; Goncharov, P. Yu.; Gusein-zade, N. G.; Ignatov, A. M.

2017-06-01

The nonlinear dynamics of beam-plasma instability in a finite magnetic field is investigated numerically. In particular, it is shown that decay instability can develop. Special attention is paid to the influence of the beam-plasma coupling factor on the spectral characteristics of a plasma relativistic microwave accelerator (PRMA) at different values of the magnetic field. It is shown that two qualitatively different physical regimes take place at two values of the external magnetic field: B 0 = 4.5 kG (Ω ω B p ) and 20 kG (Ω B ≫ ωp). For B 0 = 4.5 kG, close to the actual experimental value, there exists an optimal value of the gap length between the relativistic electron beam and the plasma (and, accordingly, an optimal value of the coupling factor) at which the PRMA output power increases appreciably, while the noise level decreases.

Construction of a 1 MeV Electron Accelerator for High Precision Beta Decay Studies

NASA Astrophysics Data System (ADS)

Longfellow, Brenden

2014-09-01

Beta decay energy calibration for detectors is typically established using conversion sources. However, the calibration points from conversion sources are not evenly distributed over the beta energy spectrum and the foil backing of the conversion sources produces perturbations in the calibration spectrum. To improve this, an external, tunable electron beam coupled by a magnetic field can be used to calibrate the detector. The 1 MeV electron accelerator in development at Triangle Universities Nuclear Laboratory (TUNL) utilizes a pelletron charging system. The electron gun shoots 104 electrons per second with an energy range of 50 keV to 1 MeV and is pulsed at a 10 kHz rate with a few ns width. The magnetic field in the spectrometer is 1 T and guiding fields of 0.01 to 0.05 T for the electron gun are used to produce a range of pitch angles. This accelerator can be used to calibrate detectors evenly over its energy range and determine the detector response over a range of pitch angles. Beta decay energy calibration for detectors is typically established using conversion sources. However, the calibration points from conversion sources are not evenly distributed over the beta energy spectrum and the foil backing of the conversion sources produces perturbations in the calibration spectrum. To improve this, an external, tunable electron beam coupled by a magnetic field can be used to calibrate the detector. The 1 MeV electron accelerator in development at Triangle Universities Nuclear Laboratory (TUNL) utilizes a pelletron charging system. The electron gun shoots 104 electrons per second with an energy range of 50 keV to 1 MeV and is pulsed at a 10 kHz rate with a few ns width. The magnetic field in the spectrometer is 1 T and guiding fields of 0.01 to 0.05 T for the electron gun are used to produce a range of pitch angles. This accelerator can be used to calibrate detectors evenly over its energy range and determine the detector response over a range of pitch angles. TUNL REU Program.

Recent results from the Mainz Microtron MAMI and an outlook for the future

NASA Astrophysics Data System (ADS)

Denig, Achim

2016-05-01

We present recent results from the Mainz Microtron MAMI, which is a high intensity electron accelerator with (polarized) beam energies up to 1.6 GeV. Currently, two major experiments are operated at MAMI. The A1 spectrometer setup is ideally suited for high-resolution electron scattering experiments, which recently led to highly competitive results on electromagnetic form factors and dark photon searches. The second experiment is the Crystal Ball/TAPS calorimeter setup (A2 collaboration), which is operated at the tagged photon beam line. At A2, the baryon spectrum in the low-energy region is investigated in photo-production experiments. A polarized target for longitudinal and transversal beam polarization in combination with the polarized beam does not only allow for experiments in this field, but also opens the avenue for investigations of the polarizabilities of the nucleons, for which new results are presented in this paper. In addition, the high rate of pseudoscalar mesons produced via photo-production allows for measurements of meson decays as motivated by precision tests of chiral perturbation theory or precision tests of the Standard Model. We also outline the physics opportunities at the accelerator MESA (Mainz Energy-Recovering Superconducting Accelerator), which is currently under construction in Mainz.

Administration of Interleukin-6 Stimulates Multilineage Hematopoiesis and Accelerates Recovery from Radiation-Induced Hematopoietic Depression

DTIC Science & Technology

1991-02-01

Htirano T, Kishimoto T, Nakahata T. Asano S: In vitro hernatopoietic growth factors. J1 Natl Cancer Inst 81: t370. 1989 expansion of the murine...a.i phas S. %’ink A. Billiau A. VanSnick 1: Identification of the nutohlbyrcmiatntrekn.Cllmuolt12. human Zh-kd protein, interferon beta ,, as a B... beta . B-cell %timulatory factor type 2 shares identity T. Takaku F. Akivama Y: In vivo effects of recombinant human with rnsanc~tc-derived

Basic fibroblast growth factor accelerates matrix degradation via a neuro-endocrine pathway in human adult articular chondrocytes.

PubMed

Im, Hee-Jeong; Li, Xin; Muddasani, Prasuna; Kim, Gun-Hee; Davis, Francesca; Rangan, Jayanthi; Forsyth, Christopher B; Ellman, Michael; Thonar, Eugene J M A

2008-05-01

Pain-related neuropeptides released from synovial fibroblasts, such as substance P, have been implicated in joint destruction. Substance P-induced inflammatory processes are mediated via signaling through a G-protein-coupled receptor, that is, neurokinin-1 tachykinin receptor (NK(1)-R). We determined the pathophysiological link between substance P and its receptor in human adult articular cartilage homeostasis. We further examined if catabolic growth factors such as basic fibroblast growth factor (bFGF or FGF-2) or IL-1beta accelerate matrix degradation via a neural pathway upregulation of substance P and NK(1)-R. We show here that substance P stimulates the production of cartilage-degrading enzymes, such as matrix metalloproteinase-13 (MMP-13), and suppresses proteoglycan deposition in human adult articular chondrocytes via NK(1)-R. Furthermore, we have demonstrated that substance P negates proteoglycan stimulation promoted by bone morphogenetic protein-7, suggesting the dual role of substance P as both a pro-catabolic and anti-anabolic mediator of cartilage homeostasis. We report that bFGF-mediated stimulation of substance P and its receptor NK(1)-R is, in part, through an IL-1beta-dependent pathway. (c) 2007 Wiley-Liss, Inc.

Basic Fibroblast Growth Factor Accelerates Matrix Degradation Via a Neuro-Endocrine Pathway in Human Adult Articular Chondrocytes

PubMed Central

IM, HEE-JEONG; LI, XIN; MUDDASANI, PRASUNA; KIM, GUN-HEE; DAVIS, FRANCESCA; RANGAN, JAYANTHI; FORSYTH, CHRISTOPHER B.; ELLMAN, MICHAEL; THONAR, EUGENE JMA

2010-01-01

Pain-related neuropeptides released from synovial fibroblasts, such as substance P, have been implicated in joint destruction. Substance P-induced inflammatory processes are mediated via signaling through a G-protein-coupled receptor, that is, neurokinin-1 tachykinin receptor (NK1-R). We determined the pathophysiological link between substance P and its receptor in human adult articular cartilage homeostasis. We further examined if catabolic growth factors such as basic fibroblast growth factor (bFGF or FGF-2) or IL-1β accelerate matrix degradation via a neural pathway upregulation of substance P and NK1-R. We show here that substance P stimulates the production of cartilage-degrading enzymes, such as matrix metalloproteinase-13 (MMP-13), and suppresses proteoglycan deposition in human adult articular chondrocytes via NK1-R. Furthermore, we have demonstrated that substance P negates proteoglycan stimulation promoted by bone morphogenetic protein-7, suggesting the dual role of substance P as both a pro-catabolic and anti-anabolic mediator of cartilage homeostasis. We report that bFGF-mediated stimulation of substance P and its receptor NK1-R is, in part, through an IL-1β-dependent pathway. PMID:17960584

Modeling human vestibular responses during eccentric rotation and off vertical axis rotation

NASA Technical Reports Server (NTRS)

Merfeld, D. M.; Paloski, W. H. (Principal Investigator)

1995-01-01

A mathematical model has been developed to help explain human multi-sensory interactions. The most important constituent of the model is the hypothesis that the nervous system incorporates knowledge of sensory dynamics into an "internal model" of these dynamics. This internal model allows the nervous system to integrate the sensory information from many different sensors into a coherent estimate of self-motion. The essence of the model is unchanged from a previously published model of monkey eye movement responses; only a few variables have been adjusted to yield the prediction of human responses. During eccentric rotation, the model predicts that the axis of eye rotation shifts slightly toward alignment with gravito-inertial force. The model also predicts that the time course of the perception of tilt following the acceleration phase of eccentric rotation is much slower than that during deceleration. During off vertical axis rotation (OVAR) the model predicts a small horizontal bias along with small horizontal, vertical, and torsional oscillations. Following OVAR stimulation, when stopped right- or left-side down, a small vertical component is predicted that decays with the horizontal post-rotatory response. All of the predictions are consistent with measurements of human responses.

Frankenswine, or bringing home the bacon

PubMed Central

2008-01-01

Xenotransplantation—specifically from pig into human—could resolve the critical shortage of organs, tissues and cells for clinical transplantation. Genetic engineering techniques in pigs are relatively well-developed and to date have largely been aimed at producing pigs that either (1) express high levels of one or more human complement-regulatory protein(s), such as decay-accelerating factor or membrane cofactor protein, or (2) have deletion of the gene responsible for the expression of the oligosaccharide, Galα1,3Gal (Gal), the major target for human anti-pig antibodies, or (3) have both manipulations. Currently the transplantation of pig organs in adequately-immunosuppressed baboons results in graft function for periods of 2–6 months (auxiliary hearts) and 2–3 months (life-supporting kidneys). Pig islets have maintained normoglycemia in diabetic monkeys for >6 months. The remaining immunologic barriers to successful xenotransplantation are discussed, and brief reviews made of (1) the potential risk of the transmission of an infectious microorganism from pig to patient and possibly to the public at large, (2) the potential physiologic incompatibilities between a pig organ and its human counterpart, (3) the major ethical considerations of clinical xenotransplantation, and (4) the possible alternatives that compete with xenotransplantation in the field of organ or cell replacement, such as mechanical devices, tissue engineering, stem cell biology and organogenesis. Finally, the proximity of clinical trials is discussed. Islet xenotransplantation is already at the stage where clinical trials are actively being considered, but the transplantation of pig organs will probably require further genetic modifications to be made to the organ-source pigs to protect their tissues from the coagulation/anticoagulation dysfunction that plays a significant role in pig graft failure after transplantation in primates. PMID:19279708

Human Rhinovirus 87 and Enterovirus 68 Represent a Unique Serotype with Rhinovirus and Enterovirus Features

PubMed Central

Blomqvist, Soile; Savolainen, Carita; Råman, Laura; Roivainen, Merja; Hovi, Tapani

2002-01-01

It has recently been reported that all but one of the 102 known serotypes of the genus Rhinovirus segregate into two genetic clusters (C. Savolainen, S. Blomqvist, M. N. Mulders, and T. Hovi, J. Gen. Virol. 83:333-340, 2002). The only exception is human rhinovirus 87 (HRV87). Here we demonstrate that HRV87 is genetically and antigenically highly similar to enterovirus 68 (EV68) and is related to EV70, the other member of human enterovirus group D. The partial nucleotide sequences of the 5′ untranslated region, capsid regions VP4/VP2 and VP1, and the 3D RNA polymerase gene of the HRV87 prototype strain F02-3607 Corn showed 97.3, 97.8, 95.2, and 95.9% identity to the corresponding regions of EV68 prototype strain Fermon. The amino acid identities were 100 and 98.1% for the products of the two capsid regions and 97.9% for 3D RNA polymerase. Antigenic cross-reaction between HRV87 and EV68 was indicated by microneutralization with monotypic antisera. Phylogenetic analysis showed definite clustering of HRV87 and EV68 with EV70 for all sequences examined. Both HRV87 and EV68 were shown to be acid sensitive by two different assays, while EV70 was acid resistant, which is typical of enteroviruses. The cytopathic effect induced by HRV87 or EV68 was inhibited by monoclonal antibodies to the decay-accelerating factor known to be the receptor of EV70. We conclude that HRV87 and EV68 are strains of the same picornavirus serotype presenting features of both rhinoviruses and enteroviruses. PMID:12409401

Xerostomia: causes and treatment.

PubMed

Wick, Jeanette Y

2007-12-01

When reduced salivary flow causes perpetual dry and sticky mucosa or sticky, stringy saliva, it becomes xerostomia-not a disease, but a symptom. Up to 30% of various populations self-report dry mouth (xerostomia) or have proven low salivary flow rates. Saliva is necessary for digestion and dental health, and it may have yet-unidentified immunological roles in humans. Xerostomia can lead to digestive problems, weight loss, and accelerated dental decay. Medications-several hundred of them-can cause or exacerbate xerostomia. Cancer, autoimmune diseases, and bone marrow transplants are associated with xerostomia. Including a dentist on the treatment team is essential for residents with dry mouth. As xerostomia progresses, they should shift focus primarily to prevention, maintenance, oral comfort, and emergency treatment. In all stages, they should keep treatment noninvasive if possible.

The human cardiovascular system during space flight

NASA Astrophysics Data System (ADS)

Grigoriev, A. I.; Kotovskaya, A. R.; Fomina, G. A.

2011-05-01

Purpose of the work is to analyze and to summarize the data of investigations into human hemodynamics performed over 20 years aboard orbital stations Salyut-7 and Mir with participation of 26 cosmonauts on space flights (SF) from 8 to 438 days in duration. The ultrasonic techniques and occlusive plethysmography demonstrated dynamics of changes in the cardiovascular system during SF of various durations. The parameters of general hemodynamics, the pumping function of the heart and arterial circulation in the brain remained stable in all the space flights; however, there were alterations in peripheral circulation associated with blood redistribution and hypovolemie in microgravity. The anti-gravity distribution of the vascular tone decayed gradually as unneeded. The most considerable changes were observed in leg vessels, equally in arteries (decrease in resistance) and veins (increase in maximum capacity). The lower body negative pressure test (LBNP) revealed deterioration of the gravity-dependent reactions that changed for the worse as SF duration extended. The cardiovascular deconditioning showed itself as loss of descent acceleration tolerance and orthostatic instability in the postflight period.

Detection of G-Induced Loss of Consciousness (G-LOC) prognosis through EMG monitoring on gastrocnemius muscle in flight.

PubMed

Booyong Choi; Yongkyun Lee; Taehwan Cho; Hyojin Koo; Dongsoo Kim

2015-08-01

G-Induced Loss of Consciousness (G-LOC) is mainly caused by the sudden acceleration in the direction of +Gz axis from the fighter pilots, and is considered as an emergent situation of which fighter pilots are constantly aware. In order to resist against G-LOC, fighter pilots are subject to run Anti-G straining maneuver (AGSM), which includes L-1 respiration maneuvering and muscular contraction of the whole body. The purpose of this study is to create a G-LOC warning alarm prior to G-LOC by monitoring the Electromyogram (EMG) of the gastrocnemius muscle on the calf, which goes under constant muscular contraction during the AGSM process. EMG data was retrieved from pilots and pilot trainees of the Korean Air Force, during when subjects were under high G-trainings on a human centrifugal simulator. Out of the EMG features, integrated absolute value (IAV), reflecting muscle contraction, and waveform length (WL), reflecting muscle contraction and fatigue, have shown a rapid decay during the alarm phase, 3 seconds before G-LOC, compared to that of a normal phase withstanding G-force. Such results showed consistency amongst pilots and pilot trainees who were under G-LOC. Based on these findings, this study developed an algorithm which can detect G-LOC prognosis during flight, and at the same time, generate warning signals. The probability of G-LOC occurrence is detected through monitoring the decay trend and degree of the IVA and WL value of when the pilot initiates AGSM during sudden acceleration above 6G. Conclusively, this G-LOC prognosis detecting and warning system is a customized, real-time countermeasure which enhanced the accuracy of detecting G-LOC.

Assessing the Effectiveness of Risk Communication for Maintenance Workers Who Deal With Induced Radioactivity Management of Medical Linear Accelerators.

PubMed

Watanabe, Hiroshi; Maehara, Yoshiaki; Fujibuchi, Toshioh; Koizumi, Mitsue; Yamaguchi, Ichiro; Kida, Tetsuo; Ooyama, Masaya; Horitsugi, Genki; Hiraki, Hitoshi; Tsukamoto, Atsuko; Itami, Jyun

2015-08-01

In Japan, an amended law that mandates levels of unintended induced radioactivity has been in effect since 1 April 2012. According to the new regulation, if the concentration of induced radioactivity in affected parts is above the clearance level, the parts must be regarded as radioactive even if they weigh less than 1 kg. This regulation reform raises several new issues concerning medical linear accelerators, including how to determine the decay period for induced radioactivity before maintenance can be performed and how to identify what parts should be considered radioactive waste. The authors performed several risk communication (RC) activities aimed at improving the understanding of maintenance workers at medical accelerator manufacturers and establishing good guidelines by involving stakeholders. For this purpose, a working group was established and conducted RC activities, such as holding opinion exchange meetings between medical staff and maintenance workers and creating a booklet to answer questions from maintenance workers. To evaluate these activities, three questionnaire surveys were conducted between 2011 and 2014. According to the results of this study, the ratio of maintenance workers who accepted "The decay period is within one week" was approximately 60% at the third survey and significantly increased (P < 0.0001) during the survey period. Approximately 25% of the maintenance workers felt that not enough information was provided about the decay period, and approximately 63% thought that the information provided on the health effects of radiation was sufficient. These results suggest that the present RC was successful.

Gamma rays from pulsar wind shock acceleration

NASA Technical Reports Server (NTRS)

Harding, Alice K.

1990-01-01

A shock forming in the wind of relativistic electron-positron pairs from a pulsar, as a result of confinement by surrounding material, could convert part of the pulsar spin-down luminosity to high energy particles through first order Fermi acceleration. High energy protons could be produced by this mechanism both in supernova remnants and in binary systems containing pulsars. The pion-decay gamma-rays resulting from interaction of accelerated protons with surrounding target material in such sources might be observable above 70 MeV with EGRET (Energetic Gamma-Ray Experimental Telescope) and above 100 GeV with ground-based detectors. Acceleration of protons and expected gamma-ray fluxes from SN1987A, Cyg X-3 type sources and binary pulsars are discussed.

New insights into the interplay between the translation machinery and nonsense-mediated mRNA decay factors.

PubMed

Raimondeau, Etienne; Bufton, Joshua C; Schaffitzel, Christiane

2018-06-19

Faulty mRNAs with a premature stop codon (PTC) are recognized and degraded by nonsense-mediated mRNA decay (NMD). Recognition of a nonsense mRNA depends on translation and on the presence of NMD-enhancing or the absence of NMD-inhibiting factors in the 3'-untranslated region. Our review summarizes our current understanding of the molecular function of the conserved NMD factors UPF3B and UPF1, and of the anti-NMD factor Poly(A)-binding protein, and their interactions with ribosomes translating PTC-containing mRNAs. Our recent discovery that UPF3B interferes with human translation termination and enhances ribosome dissociation in vitro , whereas UPF1 is inactive in these assays, suggests a re-interpretation of previous experiments and modification of prevalent NMD models. Moreover, we discuss recent work suggesting new functions of the key NMD factor UPF1 in ribosome recycling, inhibition of translation re-initiation and nascent chain ubiquitylation. These new findings suggest that the interplay of UPF proteins with the translation machinery is more intricate than previously appreciated, and that this interplay quality-controls the efficiency of termination, ribosome recycling and translation re-initiation. © 2018 The Author(s).

ICE1 promotes the link between splicing and nonsense-mediated mRNA decay

PubMed Central

Baird, Thomas D; Cheng, Ken Chih-Chien; Chen, Yu-Chi; Buehler, Eugen; Martin, Scott E; Inglese, James

2018-01-01

The nonsense-mediated mRNA decay (NMD) pathway detects aberrant transcripts containing premature termination codons (PTCs) and regulates expression of 5–10% of non-aberrant human mRNAs. To date, most proteins involved in NMD have been identified by genetic screens in model organisms; however, the increased complexity of gene expression regulation in human cells suggests that additional proteins may participate in the human NMD pathway. To identify proteins required for NMD, we performed a genome-wide RNAi screen against >21,000 genes. Canonical members of the NMD pathway were highly enriched as top hits in the siRNA screen, along with numerous candidate NMD factors, including the conserved ICE1/KIAA0947 protein. RNAseq studies reveal that depletion of ICE1 globally enhances accumulation and stability of NMD-target mRNAs. Further, our data suggest that ICE1 uses a putative MIF4G domain to interact with exon junction complex (EJC) proteins and promotes the association of the NMD protein UPF3B with the EJC. PMID:29528287

Extracting information from 0νββ decay and LHC pp-cross sections: Limits on the left-right mixing angle and right-handed boson mass

NASA Astrophysics Data System (ADS)

Civitarese, O.; Suhonen, J.; Zuber, K.

2015-10-01

The existence of massive neutrinos forces the extension of the Standard Model of electroweak interactions, to accommodate them and/or right-handed currents. This is one of the fundamental questions in todays's physics. The consequences of it would reflect upon several decay processes, like the very exotic nuclear double-beta-decay. By the other hand, high-energy proton-proton reactions of the type performed at the LHC accelerator can provide information about the existence of a right-handed generation of the W and Z-bosons. Here we shall address the possibility of performing a joint analysis of the results reported by the ATLAS and CMS collaborations (σ(pp- > 2l + jets)) and the latest measurements of nuclear-double-beta decays reported by the GERDA and EXO collaborations.

Quantum-state-selective decay spectroscopy of 213Ra

NASA Astrophysics Data System (ADS)

Lorenz, Ch.; Sarmiento, L. G.; Rudolph, D.; Ward, D. E.; Block, M.; Heßberger, F. P.; Ackermann, D.; Andersson, L.-L.; Cortés, M. L.; Droese, C.; Dworschak, M.; Eibach, M.; Forsberg, U.; Golubev, P.; Hoischen, R.; Kojouharov, I.; Khuyagbaatar, J.; Nesterenko, D.; Ragnarsson, I.; Schaffner, H.; Schweikhard, L.; Stolze, S.; Wenzl, J.

2017-09-01

An experimental scheme combining the mass resolving power of a Penning trap with contemporary decay spectroscopy has been established at GSI Darmstadt. The Universal Linear Accelerator (UNILAC) at GSI Darmstadt provided a 48Ca beam impinging on a thin 170Er target foil. Subsequent to velocity filtering of reaction products in the Separator for Heavy Ion reaction Products (SHIP), the nuclear ground state of the 5 n evaporation channel 213Ra was mass-selected in SHIPTRAP, and the 213Ra ions were finally transferred into an array of silicon strip detectors surrounded by large composite germanium detectors. Based on comprehensive geant4 simulations and supported by theoretical calculations, the spectroscopic results call for a revision of the decay path of 213Ra, thereby exemplifying the potential of a combination of a mass-selective Penning trap device with a dedicated nuclear decay station and contemporary geant4 simulations.

Extracting information from 0νββ decay and LHC pp-cross sections: Limits on the left-right mixing angle and right-handed boson mass

DOE Office of Scientific and Technical Information (OSTI.GOV)

Civitarese, O., E-mail: osvaldo.civitarese@fisica.unlp.edu.ar; Suhonen, J.; Zuber, K.

2015-10-28

The existence of massive neutrinos forces the extension of the Standard Model of electroweak interactions, to accommodate them and/or right-handed currents. This is one of the fundamental questions in todays’s physics. The consequences of it would reflect upon several decay processes, like the very exotic nuclear double-beta-decay. By the other hand, high-energy proton-proton reactions of the type performed at the LHC accelerator can provide information about the existence of a right-handed generation of the W and Z-bosons. Here we shall address the possibility of performing a joint analysis of the results reported by the ATLAS and CMS collaborations (σ(pp− >more » 2l + jets)) and the latest measurements of nuclear-double-beta decays reported by the GERDA and EXO collaborations.« less

Temperature sensitivity of organic-matter decay in tidal marshes

USGS Publications Warehouse

Kirwan, Matthew L.; Guntenspergen, Glenn R.; Langley, J.A.

2014-01-01

Approximately half of marine carbon sequestration takes place in coastal wetlands, including tidal marshes, where organic matter contributes to soil elevation and ecosystem persistence in the face of sea-level rise. The long-term viability of marshes and their carbon pools depends, in part, on how the balance between productivity and decay responds to climate change. Here, we report the sensitivity of labile soil organic-matter decay in tidal marshes to seasonal and latitudinal variations in temperature measured over a 3-year period. We find a moderate increase in decay rate at warmer temperatures (3-6% per °C, Q10 = 1.3-1.5). Despite the profound differences between microbial metabolism in wetlands and uplands, our results indicate a strong conservation of temperature sensitivity. Moreover, simple comparisons with organic-matter production suggest that elevated atmospheric CO2 and warmer temperatures will accelerate carbon accumulation in marsh soils, and potentially enhance their ability to survive sea-level rise.

Human vitamin B12 absorption measurement by accelerator mass spectrometry using specifically labeled 14C-cobalamin

PubMed Central

Carkeet, Colleen; Dueker, Stephen R.; Lango, Jozsef; Buchholz, Bruce A.; Miller, Joshua W.; Green, Ralph; Hammock, Bruce D.; Roth, John R.; Anderson, Peter J.

2006-01-01

There is a need for an improved test of human ability to assimilate dietary vitamin B12. Assaying and understanding absorption and uptake of B12 is important because defects can lead to hematological and neurological complications. Accelerator mass spectrometry is uniquely suited for assessing absorption and kinetics of carbon-14 (14C)-labeled substances after oral ingestion because it is more sensitive than decay counting and can measure levels of 14C in microliter volumes of biological samples with negligible exposure of subjects to radioactivity. The test we describe employs amounts of B12 in the range of normal dietary intake. The B12 used was quantitatively labeled with 14C at one particular atom of the dimethylbenzimidazole (DMB) moiety by exploiting idiosyncrasies of Salmonella metabolism. To grow aerobically on ethanolamine, Salmonella enterica must be provided with either preformed B12 or two of its precursors, cobinamide and DMB. When provided with 14C-DMB specifically labeled in the C2 position, cells produced 14C-B12 of high specific activity (2.1 GBq/mmol, 58 mCi/mmol) (1 Ci = 37 GBq) and no detectable dilution of label from endogenous DMB synthesis. In a human kinetic study, a physiological dose (1.5 μg, 2.2 kBq/59 nCi) of purified 14C-B12 was administered and showed plasma appearance and clearance curves consistent with the predicted behavior of the pure vitamin. This method opens new avenues for study of B12 assimilation. PMID:16585531

Sequence Divergence in the 3′ Untranslated Regions of Human ζ- and α-Globin mRNAs Mediates a Difference in Their Stabilities and Contributes to Efficient α-to-ζ Gene Developmental Switching

PubMed Central

Russell, J. Eric; Morales, Julia; Makeyev, Aleksandr V.; Liebhaber, Stephen A.

1998-01-01

The developmental stage-specific expression of human globin proteins is characterized by a switch from the coexpression of ζ- and α-globin in the embryonic yolk sac to exclusive expression of α-globin during fetal and adult life. Recent studies with transgenic mice demonstrate that in addition to transcriptional control elements, full developmental silencing of the human ζ-globin gene requires elements encoded within the transcribed region. In the current work, we establish that these latter elements operate posttranscriptionally by reducing the relative stability of ζ-globin mRNA. Using a transgenic mouse model system, we demonstrate that human ζ-globin mRNA is unstable in adult erythroid cells relative to the highly stable human α-globin mRNA. A critical determinant of the difference between α- and ζ-globin mRNA stability is mapped by in vivo expression studies to their respective 3′ untranslated regions (3′UTRs). In vitro messenger ribonucleoprotein (mRNP) assembly assays demonstrate that the α- and ζ-globin 3′UTRs assemble a previously described mRNP stability-determining complex, the α-complex, with distinctly different affinities. The diminished efficiency of α-complex assembly on the ζ 3′UTR results from a single C→G nucleotide substitution in a crucial polypyrimidine tract contained by both the human α- and ζ-globin mRNA 3′UTRs. A potential pathway for accelerated ζ-globin mRNA decay is suggested by the observation that its 3′UTR encodes a shortened poly(A) tail. Based upon these data, we propose a model for ζ-globin gene silencing in fetal and adult erythroid cells in which posttranscriptional controls play a central role by providing for accelerated clearance of ζ-globin transcripts. PMID:9528789

Effect of Aerobic Loading on Static Balance in Young Athletes

ERIC Educational Resources Information Center

Akyüz, Öznur

2017-01-01

The fact that balances can also be a factor in performance distinction between athletes in athletic skills, and is considered to provide positive acceleration for physical development in which motor skills are exhibited. Human's skill to ensure balance can be defined as a determinant factor in development of other motor skills. From this point of…

Semiempirical studies of atomic structure. Progress report, 1 July 1991--1 October 1993

DOE Office of Scientific and Technical Information (OSTI.GOV)

Curtis, L.J.

1993-10-01

Atomic structure/properties of highly ionized many-electron systems are studied using sensitive semiempirical data systematization, experiment, and theory. Measurements are made using fast ion beams, combined with data from laser- and tokamak-produced plasmas, astrophysical sources, and light sources. Results during this 3-y period are discussed under the following headings: Invited review article (decay rates in systems of negative ions to very heavy one-electron ions), fast ion beam lifetime measurements (Pt sequence, neutral carbon, Na sequence), multiplexed decay curve measurements, multiplexed decay curve measurements (lifetimes of alkali-like resonance transitions, spin-forbidden intercombination lines), lifetimes in Ne sequence, lifetimes for H and He sequences,more » data-based semiempirical formulations, calculations, and accelerator studies.« less

Radiative processes of uniformly accelerated entangled atoms

NASA Astrophysics Data System (ADS)

Menezes, G.; Svaiter, N. F.

2016-05-01

We study radiative processes of uniformly accelerated entangled atoms, interacting with an electromagnetic field prepared in the Minkowski vacuum state. We discuss the structure of the rate of variation of the atomic energy for two atoms traveling in different hyperbolic world lines. We identify the contributions of vacuum fluctuations and radiation reaction to the generation of entanglement as well as to the decay of entangled states. Our results resemble the situation in which two inertial atoms are coupled individually to two spatially separated cavities at different temperatures. In addition, for equal accelerations we obtain that one of the maximally entangled antisymmetric Bell state is a decoherence-free state.

Human fibrocyte-derived exosomes accelerate wound healing in genetically diabetic mice

DOE Office of Scientific and Technical Information (OSTI.GOV)

Geiger, Adolf, E-mail: ageiger@dreirosen-pharma.com; Walker, Audrey, E-mail: awalker@dreirosen-pharma.com; Nissen, Erwin, E-mail: enissen@dreirosen-pharma.com

Diabetic ulcers represent a substantial societal and healthcare burden worldwide and scarcely respond to current treatment strategies. This study was addressed to evaluate the therapeutic potential of exosomes secreted by human circulating fibrocytes, a population of mesenchymal progenitors involved in normal wound healing via paracrine signaling. The exosomes released from cells sequentially stimulated with platelet-derived growth factor-BB and transforming growth factor-β1, in the presence of fibroblast growth factor 2, did not show potential immunogenicity. These exosomes exhibited in-vitro proangiogenic properties, activated diabetic dermal fibroblasts, induced the migration and proliferation of diabetic keratinocytes, and accelerated wound closure in diabetic mice in vivo.more » Important components of the exosomal cargo were heat shock protein-90α, total and activated signal transducer and activator of transcription 3, proangiogenic (miR-126, miR-130a, miR-132) and anti-inflammatory (miR124a, miR-125b) microRNAs, and a microRNA regulating collagen deposition (miR-21). This proof-of-concept study demonstrates the feasibility of the use of fibrocytes-derived exosomes for the treatment of diabetic ulcers. - Highlights: • Fibrocytes have shown potent wound healing properties in vitro and in vivo. • Their clinical use is precluded by low numbers and antigen-presenting function. • We isolated exosomes with no immunogenicity potential from human fibrocytes. • Their cargo included microRNAs and proteins that are known healing promoters. • They accelerated wound closure in diabetic mice in a dose-dependent manner.« less

On the dependency of the decay of ground motion peak values with distance for small and large earthquakes

NASA Astrophysics Data System (ADS)

Dujardin, Alain; Courboulex, Françoise; Causse, Matthieu; Traversa, Paola; Monfret, Tony

2013-04-01

Ground motion decay with distance presents a clear magnitude dependence, PGA values of small events decreasing faster than those of larger events. This observation is now widely accepted and often taken into account in recent ground motion prediction equations (Anderson 2005, Akkar & Bommer 2010). The aim of this study is to investigate the origin of this dependence, which has not been clearly identified yet. Two main hypotheses are considered. On one hand the difference of ground motion decay is related to an attenuation effect, on the other hand the difference is related to an effect of extended fault (Anderson 2000). To study the role of attenuation, we realized synthetic tests using the stochastic simulation program SMSIM from Boore (2005). We build a set of simulations from several magnitudes and epicentral distances, and observe that the decay in PGA values is strongly dependent on the spectral shape of the Fourier spectra, which in turn strongly depends on the attenuation factor (Q(f) or kappa). We found that, for a point source approximation and an infinite value of Q (no attenuation) there is no difference between small and large events and that this difference increases when Q decreases. Theses results show that the influence of attenuation on spectral shape is different for earthquakes of different magnitude. In fact the influence of attenuation, which is more important at higher frequency, is larger for small earthquakes, whose Fourier acceleration spectrum has predominantly higher frequencies. We then study the effect of extended source using complete waveform simulations in a 1D model. We find that when the duration of the source time function increases, there is a larger probability to obtain large PGA values at equivalent distances. This effect could also play an important role in the PGA decay with magnitude and distance. Finally we compare these results with real datasets from the Japanese accelerometric network KIK-net.

Application of Chemical Kinetics to Deterioration of Foods.

ERIC Educational Resources Information Center

Labuza, T. P.

1984-01-01

Possible modes of food deterioration (such as microbial decay, nonenzymatic browning, senescence, lipid oxidation) are reviewed. A basic mathematical approach to the kinetics of food deterioration, kinetic approach to accelerating shelf-life deterioration, and shelf-life predictions are discussed. (JN)

High-precision half-life and branching-ratio measurements for superallowed Fermi β+ emitters at TRIUMF - ISAC

NASA Astrophysics Data System (ADS)

Laffoley, A. T.; Dunlop, R.; Finlay, P.; Grinyer, G. F.; Andreoiu, C.; Austin, R. A. E.; Ball, G. C.; Bandyopadhyay, D.; Blank, B.; Bouzomita, H.; Chagnon-Lessard, S.; Chester, A.; Cross, D. S.; Demand, G.; Diaz Varela, A.; Djongolov, M.; Ettenauer, S.; Garnsworthy, A. B.; Garrett, P. E.; Giovinazzo, J.; Glister, J.; Green, K. L.; Hackman, G.; Hadinia, B.; Jamieson, D. S.; Ketelhut, S.; Leach, K. G.; Leslie, J. R.; Pearson, C. J.; Phillips, A. A.; Rand, E. T.; Starosta, K.; Sumithrarachchi, C. S.; Svensson, C. E.; Tardiff, E. R.; Thomas, J. C.; Towner, I. S.; Triambak, S.; Unsworth, C.; Williams, S. J.; Wong, J.; Yates, S. W.; Zganjar, E. F.

2014-03-01

A program of high-precision half-life and branching-ratio measurements for superallowed Fermi β emitters is being carried out at TRIUMF's Isotope Separator and Accelerator (ISAC) radioactive ion beam facility. Recent half-life measurements for the superallowed decays of 14O, 18Ne, and 26Alm, as well as branching-ratio measurements for 26Alm and 74Rb are reported. These results provide demanding tests of the Standard Model and the theoretical isospin symmetry breaking (ISB) corrections in superallowed Fermi β decays.

Tests of a Fast Plastic Scintillator for High-Precision Half-Life Measurements

NASA Astrophysics Data System (ADS)

Laffoley, A. T.; Dunlop, R.; Finlay, P.; Leach, K. G.; Michetti-Wilson, J.; Rand, E. T.; Svensson, C. E.; Grinyer, G. F.; Thomas, J. C.; Ball, G.; Garnsworthy, A. B.; Hackman, G.; Orce, J. N.; Triambak, S.; Williams, S. J.; Andreoiu, C.; Cross, D.

2013-03-01

A fast plastic scintillator detector is evaluated for possible use in an ongoing program of high-precision half-life measurements of short lived β emitters. Using data taken at TRI-UMF's Isotope Separator and Accelerator Facility with a radioactive 26Na beam, a detailed investigation of potential systematic effects with this new detector setup is being performed. The technique will then be applied to other β-decay half-life measurements including the superallowed Fermi β emitters 10C, 14O, and T = 1/2 decay of 15O.

Diagnostic Development for E-Beam Excited Air Channels. Microwave Cavity Reflection Interferometer for Single-Pulse Transient Conductivity Measurements

DTIC Science & Technology

1987-04-01

for two applications important to the development of charged particle beam propagation studies. The first application is to measure the decay of...at Los Alamos4 and the Medea accelerator at McDonnell- Douglas Research Laboratory.5 The second application is to measure the conductivity generated...for the first time. For slightly higher rep-rate accelerators such as Medea or PHERMEX, it will improve the accuracy of the results by eliminating pulse

Reliability of vibration energy harvesters of metal-based PZT thin films

NASA Astrophysics Data System (ADS)

Tsujiura, Y.; Suwa, E.; Kurokawa, F.; Hida, H.; Kanno, I.

2014-11-01

This paper describes the reliability of piezoelectric vibration energy harvesters (PVEHs) of Pb(Zr,Ti)O3 (PZT) thin films on metal foil cantilevers. The PZT thin films were directly deposited onto the Pt-coated stainless-steel (SS430) cantilevers by rf-magnetron sputtering, and we observed their aging behavior of power generation characteristics under the resonance vibration condition for three days. During the aging measurement, there was neither fatigue failure nor degradation of dielectric properties in our PVEHs (length: 13 mm, width: 5.0 mm, thickness: 104 μm) even under a large excitation acceleration of 25 m/s2. However, we observed clear degradation of the generated electric voltage depending on excitation acceleration. The decay rate of the output voltage was 5% from the start of the measurement at 25 m/s2. The transverse piezoelectric coefficient (e31,f) also degraded with almost the same decay rate as that of the output voltage; this indicates that the degradation of output voltage was mainly caused by that of piezoelectric properties. From the decay curves, the output powers are estimated to degrade 7% at 15 m/s2 and 36% at 25 m/s2 if we continue to excite the PVEHs for 30 years.

Aerobic Fitness is Associated With Hippocampal Volume in Elderly Humans

PubMed Central

Erickson, Kirk I.; Prakash, Ruchika S.; Voss, Michelle W.; Chaddock, Laura; Hu, Liang; Morris, Katherine S.; White, Siobhan M.; Wójcicki, Thomas R.; McAuley, Edward; Kramer, Arthur F.

2010-01-01

Deterioration of the hippocampus occurs in elderly individuals with and without dementia, yet individual variation exists in the degree and rate of hippocampal decay. Determining the factors that influence individual variation in the magnitude and rate of hippocampal decay may help promote lifestyle changes that prevent such deterioration from taking place. Aerobic fitness and exercise are effective at preventing cortical decay and cognitive impairment in older adults and epidemiological studies suggest that physical activity can reduce the risk for developing dementia. However, the relationship between aerobic fitness and hippocampal volume in elderly humans is unknown. In this study, we investigated whether individuals with higher levels of aerobic fitness displayed greater volume of the hippocampus and better spatial memory performance than individuals with lower fitness levels. Furthermore, in exploratory analyses, we assessed whether hippocampal volume mediated the relationship between fitness and spatial memory. Using a region-of-interest analysis on magnetic resonance images in 165 nondemented older adults, we found a triple association such that higher fitness levels were associated with larger left and right hippocampi after controlling for age, sex, and years of education, and larger hippocampi and higher fitness levels were correlated with better spatial memory performance. Furthermore, we demonstrated that hippocampal volume partially mediated the relationship between higher fitness levels and enhanced spatial memory. Our results clearly indicate that higher levels of aerobic fitness are associated with increased hippocampal volume in older humans, which translates to better memory function. PMID:19123237

Recombinant Factor VIIa Reduces Rebleed Hemorrhage Volume in a Swine Aortotomy Model: A Randomized Double-Blinded Study

DTIC Science & Technology

2008-06-01

Bpops,[ a dose of 90 Hg kgj1 will produce serum concentrations of factor VII high enough to reduce hemorrhage by accelerating thrombin production and...interaction is species-specific, and human FVII seems to have only between 5% and 50% activity when exposed to porcine tissue factor (15). The results...Copyright @ 200 by the Shock Society. Unauthorized reproduction of this article is prohibited.8 RECOMBINANT FACTOR VIIA REDUCES REBLEED HEMORRHAGE

Matter Under Extreme Conditions

DTIC Science & Technology

2006-03-01

decay of topological defects, or dark matter particles; however, also the acceleration of protons to high energy, and their subsequent interaction to...dominating now and why does it have a comparable contribution to the energy density as the dark matter ? I will try and introduce the observational

Large Scale Underground Detectors in Europe

NASA Astrophysics Data System (ADS)

Katsanevas, S. K.

2006-07-01

The physics potential and the complementarity of the large scale underground European detectors: Water Cherenkov (MEMPHYS), Liquid Argon TPC (GLACIER) and Liquid Scintillator (LENA) is presented with emphasis on the major physics opportunities, namely proton decay, supernova detection and neutrino parameter determination using accelerator beams.

First-order particle acceleration in magnetically driven flows

DOE PAGES

Beresnyak, Andrey; Li, Hui

2016-03-02

In this study, we demonstrate that particles are regularly accelerated while experiencing curvature drift in flows driven by magnetic tension. Some examples of such flows include spontaneous turbulent reconnection and decaying magnetohydrodynamic turbulence, where a magnetic field relaxes to a lower-energy configuration and transfers part of its energy to kinetic motions of the fluid. We show that this energy transfer, which normally causes turbulent cascade and heating of the fluid, also results in a first-order acceleration of non-thermal particles. Since it is generic, this acceleration mechanism is likely to play a role in the production of non-thermal particle distribution inmore » magnetically dominant environments such as the solar chromosphere, pulsar magnetospheres, jets from supermassive black holes, and γ-ray bursts.« less

Integrated capabilities in heavy vehicles : human factors research needs

DOT National Transportation Integrated Search

2003-10-09

The Full Road Closure method uses facility closure and total traffic diversion, which may be for one direction or bi-directional traffic flow, to accelerate construction and reduce the negative impacts of work zones. With good planning, interagency c...

Converging social classes through humanized urban edges

NASA Astrophysics Data System (ADS)

Abuan, M. V.; Galingan, Z. D.

2017-10-01

Urban open spaces are created to be used by people. It is a place of convergence and social activity. However, these places have transformed into places of divergence. When spaces become dehumanized, it separates social classes. As a result, underused spaces contribute to urban decay. Particularly an urban edge, the JP Rizal Makati Waterfront Area is the center of this paper. The JP Rizal Makati Waterfront Area is a waterfront development situated along the banks of one of Metro Manila’s major water thoroughfare --- Pasig River. The park and its physical form, urban design and landscape tend to deteriorate over time --- creating a further division of social convergence. Social hostility, crime, negligent maintenance and poor urban design are contributing factors to this sprawling decay in what used to be spaces of bringing people together. Amidst attempts to beautify and renew this portion of Makati City’s edge, the urban area still remains misspent.This paper attempts to re-humanize the waterfront development. It uses the responsive environment design principles to be able to achieve this goal.

Decaying and growing eigenmodes in open quantum systems: Biorthogonality and the Petermann factor

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lee, Soo-Young

2009-10-15

We study the biorthogonality between decaying and growing eigenmodes in one-dimensional potential barrier problems. It is shown that Petermann factors K{sub n} of the eigenmodes, a measure of nonorthogonality, are involved in decaying mechanism of an initially confined particle. We also show that the decay tail of the growing modes at an exceptional point (EP), where K{sub n} become infinite, is not exponential, but {approx}t{sup 2}e{sup -{gamma}{sub EP}t}, {gamma}{sub EP} the decay rate of the decaying mode at EP. In addition, the geometrical phase near an EP is illustrated by the evolution of wave function.

Impact accelerations

NASA Technical Reports Server (NTRS)

Vongierke, H. E.; Brinkley, J. W.

1975-01-01

The degree to which impact acceleration is an important factor in space flight environments depends primarily upon the technology of capsule landing deceleration and the weight permissible for the associated hardware: parachutes or deceleration rockets, inflatable air bags, or other impact attenuation systems. The problem most specific to space medicine is the potential change of impact tolerance due to reduced bone mass and muscle strength caused by prolonged weightlessness and physical inactivity. Impact hazards, tolerance limits, and human impact tolerance related to space missions are described.

The Role of Triplet Exciton Diffusion in Light-Upconverting Polymer Glasses.

PubMed

Raišys, Steponas; Kazlauskas, Karolis; Juršėnas, Saulius; Simon, Yoan C

2016-06-22

Light upconversion (UC) via triplet-triplet annihilation (TTA) by using noncoherent photoexcitation at subsolar irradiance power densities is extremely attractive, particularly for enhanced solar energy harvesting. Unfortunately, practical TTA-UC application is hampered by low UC efficiency of upconverting polymer glasses, which is commonly attributed to poor exciton diffusion of the triplet excitons across emitter molecules. The present study addresses this issue by systematically evaluating triplet exciton diffusion coefficients and diffusion lengths (LD) in a UC model system based on platinum-octaethylporphyrin-sensitized poly(methyl methacrylate)/diphenylanthracene (emitter) films as a function of emitter concentration (15-40 wt %). For this evaluation time-resolved photoluminescence bulk-quenching technique followed by Stern-Volmer-type quenching analysis of experimental data was employed. The key finding is that although increasing emitter concentration in the disordered PMMA/DPA/PtOEP films improves triplet exciton diffusion, and thus LD, this does not result in enhanced UC quantum yield. Conversely, improved LD accompanied by the accelerated decay of UC intensity on millisecond time scale degrades TTA-UC performance at high emitter loadings (>25 wt %) and suggests that diffusion-enhanced nonradiative decay of triplet excitons is the major limiting factor.

Branching ratio measurements of B meson decays to J/psi meson eta meson kaon and charged B meson decays to neutral D meson charged kaon with neutral D meson decays to positive pion negative pion neutral pion

NASA Astrophysics Data System (ADS)

Zeng, Qinglin

Results are presented for the decays of B → J/psietaK and B+/- → DK+/-, respectively, with experimental data collected with BABAR detector at PEP-II, located at Stanford Linear Accelerator Center (SLAC). With 90 x 106 BB¯ events at the Upsilon(4S) resonance, we obtained branching fractions of B (B+/- → J/psietaK +/-) = [10.8 +/- 2.3(stat) +/- 2.4(syst)] x 10-5 and B (B0 → J/psieta K0S ) = [8.4 +/- 2.6(stat) +/- 2.7( syst)] x 10-5; and we set an upper limit of B [B+/- → X(3872) K+/- → J/psietaK +/-] < 7.7 x 10-6 at 90% confidence level. The branching fraction of decay chain B (B+/- → DK +/- → pi+pi-pi 0K+/-) = [5.5 +/- 1.0( stat) +/- 0.7(syst)] x 10-6 with 229 x 106 BB¯ events at Upsilon(4S) resonance, here D represents the neutral D meson. The decay rate asymmetry is A = 0.02 +/- 0.16(stat) +/- 0.03(syst) for this full decay chain. This decay can be used to extract the unitarity angle gamma, a weak CP violation phase, through the interference of decay production of D0 and D¯ 0 to pi+pi-pi 0.

CORONAS-F observation of gamma-ray emission from the solar flare on 2003 October 29

NASA Astrophysics Data System (ADS)

Kurt, Victoria G.; Yushkov, Boris Yu.; Galkin, Vladimir I.; Kudela, Karel; Kashapova, Larisa K.

2017-10-01

Appreciable hard X-ray (HXR) and gamma-ray emissions in the 0.04-150 MeV energy range associated with the 2003 October 29 solar flare (X10/3B) were observed at 20:38-20:58 UT by the SONG instrument onboard the CORONAS-F mission. To restore flare gamma-ray spectra we fitted the SONG energy loss spectra with a three-component model of the incident spectrum: (1) a power law in energy, assumed to be due to electron bremsstrahlung; (2) a broad continuum produced by prompt nuclear de-excitation gamma-lines; and (3) a broad gamma-line generated from pion-decay. We also restored spectra from the RHESSI data, compared them with the SONG spectra and found a reasonable agreement between these spectra in the 0.1-10 MeV energy range. The pion-decay emission was observed from 20:44:20 UT and had its maximum at 20:48-20:51 UT. The power-law spectral index of accelerated protons estimated from the ratio between intensities of different components of gamma rays changed with time. The hardest spectrum with a power-law index S = -3.5 - 3.6 was observed at 20:48-20:51 UT. Time histories of the pion-decay emission and proton spectrum were compared with changes of the locations of flare energy release as shown by RHESSI hard X-ray images and remote and remote Hα brightenings. An apparent temporal correlation between processes of particle acceleration and restructuring of flare magnetic field was found. In particular, the protons were accelerated to subrelativistic energies after radical change of the character of footpoint motion from a converging motion to a separation motion.

mRNA–mRNA duplexes that auto-elicit Staufen1-mediated mRNA decay

PubMed Central

Gong, Chenguang; Tang, Yalan; Maquat, Lynne E.

2013-01-01

We report a new mechanism by which human mRNAs crosstalk: an Alu element in the 3'-untranslated region (3' UTR) of one mRNA can base-pair with a partially complementary Alu element in the 3' UTR of a different mRNA thereby creating a Staufen1 (STAU1)-binding site (SBS). STAU1 binding to a 3' UTR SBS was previously shown to trigger STAU1-mediated mRNA decay (SMD) by directly recruiting the ATP-dependent RNA helicase UPF1, which is also a key factor in the mechanistically related nonsense-mediated mRNA decay (NMD) pathway. In the case of a 3' UTR SBS created via mRNA–mRNA base-pairing, we show that SMD targets both mRNAs in the duplex provided that both mRNAs are translated. If only one mRNA is translated, then it alone is targeted for SMD. We demonstrate the importance of mRNA–mRNA-triggered SMD to the processes of cell migration and invasion. PMID:24056942

Charmless B_{(s)}→ VV decays in factorization-assisted topological-amplitude approach

NASA Astrophysics Data System (ADS)

Wang, Chao; Zhang, Qi-An; Li, Ying; Lü, Cai-Dian

2017-05-01

Within the factorization-assisted topological-amplitude approach, we studied the 33 charmless B_{(s)} → VV decays, where V stands for a light vector meson. According to the flavor flows, the amplitude of each process can be decomposed into eight different topologies. In contrast to the conventional flavor diagrammatic approach, we further factorize each topological amplitude into decay constant, form factors and unknown universal parameters. By χ ^2 fitting 46 experimental observables, we extracted 10 theoretical parameters with χ ^2 per degree of freedom around 2. Using the fitted parameters, we calculated the branching fractions, polarization fractions, CP asymmetries and relative phases between polarization amplitudes of each decay mode. The decay channels dominated by tree diagram have large branching fractions and large longitudinal polarization fraction. The branching fractions and longitudinal polarization fractions of color-suppressed decays become smaller. Current experimental data of large transverse polarization fractions in the penguin dominant decay channels can be explained by only one transverse amplitude of penguin annihilation diagram. Our predictions of the not yet measured channels can be tested in the ongoing LHCb experiment and the Belle-II experiment in the future.

Physics at the SPS.

PubMed

Gatignon, L

2018-05-01

The CERN Super Proton Synchrotron (SPS) has delivered a variety of beams to a vigorous fixed target physics program since 1978. In this paper, we restrict ourselves to the description of a few illustrative examples in the ongoing physics program at the SPS. We will outline the physics aims of the COmmon Muon Proton Apparatus for Structure and Spectroscopy (COMPASS), north area 64 (NA64), north area 62 (NA62), north area 61 (NA61), and advanced proton driven plasma wakefield acceleration experiment (AWAKE). COMPASS studies the structure of the proton and more specifically of its spin. NA64 searches for the dark photon A', which is the messenger for interactions between normal and dark matter. The NA62 experiment aims at a 10% precision measurement of the very rare decay K + → π + νν. As this decay mode can be calculated very precisely in the Standard Model, it offers a very good opportunity to look for new physics beyond the Standard Model. The NA61/SHINE experiment studies the phase transition to Quark Gluon Plasma, a state in which the quarks and gluons that form the proton and the neutron are de-confined. Finally, AWAKE investigates proton-driven wake field acceleration: a promising technique to accelerate electrons with very high accelerating gradients. The Physics Beyond Colliders study at CERN is paving the way for a significant and diversified continuation of this already rich and compelling physics program that is complementary to the one at the big colliders like the Large Hadron Collider.

Effects of haloperidol on Kv4.3 potassium channels.

PubMed

Lee, Hong Joon; Sung, Ki-Wug; Hahn, Sang June

2014-10-05

Haloperidol is commonly used in clinical practice to treat acute and chronic psychosis, but it also has been associated with adverse cardiovascular events. We investigated the effects of haloperidol on Kv4.3 currents stably expressed in CHO cells using a whole-cell patch-clamp technique. Haloperidol did not significantly inhibit the peak amplitude of Kv4.3, but accelerated the decay rate of inactivation of Kv4.3 in a concentration-dependent manner. Thus, the effects of haloperidol on Kv4.3 were estimated from the integral of the Kv4.3 currents during the depolarization pulse. The Kv4.3 was decreased by haloperidol in a concentration-dependent manner with an IC50 value of 3.6 μM. Haloperidol accelerated the decay rate of Kv4.3 inactivation and activation kinetics in a concentration-dependent manner, thereby decreasing the time-to-peak. Haloperidol shifted the voltage dependence of the steady-state activation and inactivation of Kv4.3 in a hyperpolarizing direction. Haloperidol also caused an acceleration of the closed-state inactivation of Kv4.3. Haloperidol produced a use-dependent block of Kv4.3, which was accompanied by a slowing of recovery from the inactivation of Kv4.3. These results suggest that haloperidol blocks Kv4.3 by both interacting with the open state of Kv4.3 channels during depolarization and accelerating the closed-state inactivation at subthreshold membrane potentials. Copyright © 2014 Elsevier B.V. All rights reserved.

Physics at the SPS

NASA Astrophysics Data System (ADS)

Gatignon, L.

2018-05-01

The CERN Super Proton Synchrotron (SPS) has delivered a variety of beams to a vigorous fixed target physics program since 1978. In this paper, we restrict ourselves to the description of a few illustrative examples in the ongoing physics program at the SPS. We will outline the physics aims of the COmmon Muon Proton Apparatus for Structure and Spectroscopy (COMPASS), north area 64 (NA64), north area 62 (NA62), north area 61 (NA61), and advanced proton driven plasma wakefield acceleration experiment (AWAKE). COMPASS studies the structure of the proton and more specifically of its spin. NA64 searches for the dark photon A', which is the messenger for interactions between normal and dark matter. The NA62 experiment aims at a 10% precision measurement of the very rare decay K+ → π+νν. As this decay mode can be calculated very precisely in the Standard Model, it offers a very good opportunity to look for new physics beyond the Standard Model. The NA61/SHINE experiment studies the phase transition to Quark Gluon Plasma, a state in which the quarks and gluons that form the proton and the neutron are de-confined. Finally, AWAKE investigates proton-driven wake field acceleration: a promising technique to accelerate electrons with very high accelerating gradients. The Physics Beyond Colliders study at CERN is paving the way for a significant and diversified continuation of this already rich and compelling physics program that is complementary to the one at the big colliders like the Large Hadron Collider.

Characterization of the radiation environment at the UNLV accelerator facility during operation of the Varian M6 linac

NASA Astrophysics Data System (ADS)

Hodges, M.; Barzilov, A.; Chen, Y.; Lowe, D.

2016-10-01

The bremsstrahlung photon flux from the UNLV particle accelerator (Varian M6 model) was determined using MCNP5 code for 3 MeV and 6 MeV incident electrons. Human biological equivalent dose rates due to accelerator operation were evaluated using the photon flux with the flux-to-dose conversion factors. Dose rates were computed for the accelerator facility for M6 linac use under different operating conditions. The results showed that the use of collimators and linac internal shielding significantly reduced the dose rates throughout the facility. It was shown that the walls of the facility, in addition to the earthen berm enveloping the building, provide equivalent shielding to reduce dose rates outside to below the 2 mrem/h limit.

ϕ-meson photoproduction on hydrogen in the neutral decay mode

NASA Astrophysics Data System (ADS)

Seraydaryan, H.; Amaryan, M. J.; Gavalian, G.; Baghdasaryan, H.; Weinstein, L.; Adhikari, K. P.; Adikaram, D.; Aghasyan, M.; Anderson, M. D.; Pereira, S. Anefalos; Avakian, H.; Ball, J.; Baltzell, N. A.; Battaglieri, M.; Batourine, V.; Bedlinskiy, I.; Bennett, R. P.; Biselli, A. S.; Bono, J.; Boiarinov, S.; Briscoe, W. J.; Brooks, W. K.; Bültmann, S.; Burkert, V. D.; Carman, D. S.; Celentano, A.; Chandavar, S.; Collins, P.; Contalbrigo, M.; Cortes, O.; Crede, V.; D'Angelo, A.; Dashyan, N.; De Vita, R.; De Sanctis, E.; Deur, A.; Djalali, C.; Doughty, D.; Dugger, M.; Dupre, R.; Fassi, L. El; Eugenio, P.; Fedotov, G.; Fegan, S.; Fersch, R.; Fleming, J. A.; Gevorgyan, N.; Giovanetti, K. L.; Girod, F. X.; Goetz, J. T.; Gohn, W.; Golovatch, E.; Gothe, R. W.; Griffioen, K. A.; Guidal, M.; Guler, N.; Guo, L.; Hafidi, K.; Hakobyan, H.; Hanretty, C.; Harrison, N.; Heddle, D.; Hicks, K.; Ho, D.; Holtrop, M.; Hyde, C. E.; Ilieva, Y.; Ireland, D. G.; Ishkhanov, B. S.; Isupov, E. L.; Jo, H. S.; Joo, K.; Keller, D.; Khandaker, M.; Kim, A.; Kim, W.; Klein, F. J.; Koirala, S.; Kubarovsky, A.; Kubarovsky, V.; Kuhn, S. E.; Kuleshov, S. V.; Lewis, S.; Livingston, K.; Lu, H. Y.; MacGregor, I. J. D.; Martinez, D.; Mayer, M.; McKinnon, B.; Mineeva, T.; Mirazita, M.; Mokeev, V.; Montgomery, R. A.; Moutarde, H.; Munevar, E.; Camacho, C. Munoz; Nadel-Turonski, P.; Nasseripour, R.; Niccolai, S.; Niculescu, I.; Osipenko, M.; Ostrovidov, A. I.; Pappalardo, L. L.; Paremuzyan, R.; Park, K.; Park, S.; Pasyuk, E.; Phelps, E.; Phillips, J. J.; Pisano, S.; Pogorelko, O.; Pozdniakov, S.; Price, J. W.; Protopopescu, D.; Puckett, A. J. R.; Rimal, D.; Ripani, M.; Ritchie, B. G.; Rizzo, A.; Rosner, G.; Rossi, P.; Sabatié, F.; Saini, M. S.; Salgado, C.; Schott, D.; Schumacher, R. A.; Seder, E.; Sharabian, Y. G.; Smith, G. D.; Sober, D. I.; Sokhan, D.; Stepanyan, S.; Stoler, P.; Strakovsky, I. I.; Strauch, S.; Tang, W.; Taylor, C. E.; Tian, Ye; Tkachenko, S.; Ungaro, M.; Vineyard, M. F.; Voskanyan, H.; Voutier, E.; Walford, N. K.; Watts, D. P.; Weinstein, L. B.; Wood, M. H.; Zachariou, N.; Zana, L.; Zhang, J.; Zhao, Z. W.; CLAS Collaboration

2014-05-01

We report the first measurement of the photoproduction cross section of the ϕ meson in its neutral decay mode in the reaction γp →pϕ(KSKL). The experiment was performed with a tagged photon beam of energy 1.6≤Eγ≤3.6 GeV incident on a liquid hydrogen target of the CLAS spectrometer at the Thomas Jefferson National Accelerator Facility. The pϕ final state is identified via reconstruction of KS in the invariant mass of two oppositely charged pions and by requiring the missing particle in the reaction γp →pKSX to be KL. The presented results significantly enlarge the existing data on ϕ photoproduction. These data, combined with the data from the charged decay mode, will help to constrain different mechanisms of ϕ photoproduction.

High precision measurements of 26Naβ- decay

NASA Astrophysics Data System (ADS)

Grinyer, G. F.; Svensson, C. E.; Andreoiu, C.; Andreyev, A. N.; Austin, R. A.; Ball, G. C.; Chakrawarthy, R. S.; Finlay, P.; Garrett, P. E.; Hackman, G.; Hardy, J. C.; Hyland, B.; Iacob, V. E.; Koopmans, K. A.; Kulp, W. D.; Leslie, J. R.; MacDonald, J. A.; Morton, A. C.; Ormand, W. E.; Osborne, C. J.; Pearson, C. J.; Phillips, A. A.; Sarazin, F.; Schumaker, M. A.; Scraggs, H. C.; Schwarzenberg, J.; Smith, M. B.; Valiente-Dobón, J. J.; Waddington, J. C.; Wood, J. L.; Zganjar, E. F.

2005-04-01

High-precision measurements of the half-life and β-branching ratios for the β- decay of 26Na to 26Mg have been measured in β-counting and γ-decay experiments, respectively. A 4π proportional counter and fast tape transport system were employed for the half-life measurement, whereas the γ rays emitted by the daughter nucleus 26Mg were detected with the 8π γ-ray spectrometer, both located at TRIUMF's isotope separator and accelerator radioactive beam facility. The half-life of 26Na was determined to be T1/2=1.07128±0.00013±0.00021s, where the first error is statistical and the second systematic. The logft values derived from these experiments are compared with theoretical values from a full sd-shell model calculation.

Measurement of the muon charge asymmetry in pp decaying to W + X decaying to mu nu + X events using the D0 detector

NASA Astrophysics Data System (ADS)

Hoang, Trang Thi Kieu

This dissertation describes a measurement of the muon charge asymmetry from W → munu decay using 7.3 fb-1 of data collected from April 2002 to July 2010 using the D0 detector at Fermi National Accelerator Laboratory. The measurement for muons with pseudorapidity |eta| < 2 probes the charge asymmetry for momentum fraction x from 0.005 to 0.3. The charge asymmetry is compared with the theory predictions generated from RESBOS with CTEQ6.6 parton distribution functions, and from POWHEG with CT10 and MSTW2008 PDFs. The results show good agreement with the electron charge asymmetry measurement from D0. So far, our measurement is the most precise lepton charge asymmetry measurement done at the Tevatron.

Science Based Stockpile Stewardship

DTIC Science & Technology

1994-11-01

camera, and to do tomography from the data. This is a standard medical imaging procedure (SPECT: Single-photon emission com- puted tomography ). We do...interest remain the obser- vations of extremely rare branching ratios of the decays of muons and pions. 4. Accelerator-based Power Sources (APS). The

Modern Elementary Particle Physics

NASA Astrophysics Data System (ADS)

Kane, Gordon

2017-02-01

1. Introduction; 2. Relativistic notation, Lagrangians, and interactions; 3. Gauge invariance; 4. Non-abelian gauge theories; 5. Dirac notation for spin; 6. The Standard Model Lagrangian; 7. The electroweak theory and quantum chromodynamics; 8. Masses and the Higgs mechanism; 9. Cross sections, decay widths, and lifetimes: W and Z decays; 10. Production and properties of W± and Zᴼ; 11. Measurement of electroweak and QCD parameters: the muon lifetime; 12. Accelerators - present and future; 13. Experiments and detectors; 14. Low energy and non-accelerator experiments; 15. Observation of the Higgs boson at the CERN LHC: is it the Higgs boson?; 16. Colliders and tests of the Standard Model: particles are pointlike; 17. Quarks and gluons, confinement and jets; 18. Hadrons, heavy quarks, and strong isospin invariance; 19. Coupling strengths depend on momentum transfer and on virtual particles; 20. Quark (and lepton) mixing angles; 21. CP violation; 22. Overview of physics beyond the Standard Model; 23. Grand unification; 24. Neutrino masses; 25. Dark matter; 26. Supersymmetry.

Recent Developments in Young-Earth Creationist Geology

NASA Astrophysics Data System (ADS)

Heaton, Timothy H.

2009-10-01

Young-earth creationism has undergone a shift in emphasis toward building of historical models that incorporate Biblical and scientific evidence and the acceptance of scientific conclusions that were formerly rejected. The RATE Group admitted that massive amounts of radioactive decay occurred during earth history but proposed a period of accelerated decay during Noah’s Flood to fit the resulting history into a young-earth timeframe. Finding a mechanism for the acceleration and dealing with the excessive heat and radiation it would generate posed major problems for the project. Catastrophic plate tectonics was proposed to explain continental movements in a short timeframe and serve as a trigger for Noah’s Flood, but other creationists rejected the idea citing hopeless chronological problems. Creationists have also sought to explain the order of the fossil record and the Ice Age in a young-earth timeframe. An examination of these efforts demonstrates the anti-scientific nature of using the Bible as a non-negotiable framework for earth history.

Neural processing of gravito-inertial cues in humans. II. Influence of the semicircular canals during eccentric rotation.

PubMed

Merfeld, D M; Zupan, L H; Gifford, C A

2001-04-01

All linear accelerometers, including the otolith organs, respond equivalently to gravity and linear acceleration. To investigate how the nervous system resolves this ambiguity, we measured perceived roll tilt and reflexive eye movements in humans in the dark using two different centrifugation motion paradigms (fixed radius and variable radius) combined with two different subject orientations (facing-motion and back-to-motion). In the fixed radius trials, the radius at which the subject was seated was held constant while the rotation speed was changed to yield changes in the centrifugal force. In variable radius trials, the rotation speed was held constant while the radius was varied to yield a centrifugal force that nearly duplicated that measured during the fixed radius condition. The total gravito-inertial force (GIF) measured by the otolith organs was nearly identical in the two paradigms; the primary difference was the presence (fixed radius) or absence (variable radius) of yaw rotational cues. We found that the yaw rotational cues had a large statistically significant effect on the time course of perceived tilt, demonstrating that yaw rotational cues contribute substantially to the neural processing of roll tilt. We also found that the orientation of the subject relative to the centripetal acceleration had a dramatic influence on the eye movements measured during fixed radius centrifugation. Specifically, the horizontal vestibuloocular reflex (VOR) measured in our human subjects was always greater when the subject faced the direction of motion than when the subjects had their backs toward the motion during fixed radius rotation. This difference was consistent with the presence of a horizontal translational VOR response induced by the centripetal acceleration. Most importantly, by comparing the perceptual tilt responses to the eye movement responses, we found that the translational VOR component decayed as the subjective tilt indication aligned with the tilt of the GIF. This was true for both the fixed radius and variable radius conditions even though the time course of the responses was significantly different for these two conditions. These findings are consistent with the hypothesis that the nervous system resolves the ambiguous measurements of GIF into neural estimates of gravity and linear acceleration. More generally, these findings are consistent with the hypothesis that the nervous system uses internal models to process and interpret sensory motor cues.

Refining Binary Pulsar B1913+16's Gravitational Wave Test via a VLBI Parallax Measurement

NASA Astrophysics Data System (ADS)

Weisberg, Joel; Deller, Adam; Chatterjee, Shami; Nice, David

2018-01-01

The orbital decay of binary pulsar B1913+16 provided the first evidence of gravitational waves as predicted by General Relativity, and ruled out numerous previously viable alternative gravitational theories (e.g., Taylor & Weisberg, APJ, 253, 908, 1982). The gravitational wave emission and resulting orbital decay manifest themselves as an orbital period derivative. Subsequent observations (e.g., Weisberg and Huang 2016, APJ, 829, 55) have greatly refined the precision of the orbital period derivative measurement. The accuracy of the experiment is currently limited by our knowledge of the relative galactic accelerations of the binary and solar system barycenters, which make another contribution to the observed orbital period derivative. The magnitude of these accelerations depend on various galactic constants and on the pulsar distance.As our knowledge of the Galaxy and its motions has improved, the pulsar's distance has become the largest remaining source of uncertainty in the experiment.Therefore, we conducted a series of astrometric measurements of PSR B1913+16 with the Very Long Baseline Array. We report the pulsar parallax and distance derived from these measurements, and use them to correct our observed orbital period derivative for the above galactic acceleration term, thereby providing a more accurate test of gravitational radiation emission from the system.

Temporal relationship between high-energy proton acceleration and magnetic field changes during solar flares

NASA Astrophysics Data System (ADS)

Kurt, Victoria; Yushkov, Boris

Understanding of the association of the magnetic field evolution in the corona and the temporal evolution of electromagnetic emissions produced by the accelerated particles during a solar flare can provide information about the nature of the energy-release process and its location. Recent high-spatial-resolution observations in HXR, UV and radio emissions allow one to study in detail a structure of two-ribbon flare site. According to these observations, the flare process can be divided into two different intervals with different temporal evolution of morphological structure: loop contraction during impulsive phase and subsequent loop expansion. On the other hand, the appearance of high-energy protons (with energy >300 MeV - an energy threshold of the pion production) in the solar atmosphere can be revealed from an emerging pion-decay component of high-energy gamma-ray emission. The present work is based on comparison of measurements of high-energy gamma-rays performed with the SONG detector onboard the CORONAS-F mission and reported observations of magnetic field evolution, such as HXR foot points (FP) separation and flare shear temporal behavior, or motion of UV/radio loops. We reliably identified the pion-decay component of gamma-ray emission in the course of five events attended with suitable spatial observations, namely, 2001 August 25, 2002 August 24, 2003 October 28, 2003 October 29, and 2005 January 20, and determined its onset time. We found that in these events the pion-decay emission occurred when the distance between conjugated foot-points of flare loops ceased to decrease and began to increase, i.e. changed from shrinkage to expansion. This result leads to the conclusion that the most efficient proton acceleration up to >300 MeV coincided in time with the radical reconfiguration of the magnetic field in the flare site. Earlier we found that the pion-decay emission onset in the 2003 October 28 flare was close to the time of maximum change rate of the magnetic flux calculated by Miklenic et al. (2009).

The application of artificial intelligent techniques to accelerator operations at McMaster University

NASA Astrophysics Data System (ADS)

Poehlman, W. F. S.; Garland, Wm. J.; Stark, J. W.

1993-06-01

In an era of downsizing and a limited pool of skilled accelerator personnel from which to draw replacements for an aging workforce, the impetus to integrate intelligent computer automation into the accelerator operator's repertoire is strong. However, successful deployment of an "Operator's Companion" is not trivial. Both graphical and human factors need to be recognized as critical areas that require extra care when formulating the Companion. They include interactive graphical user's interface that mimics, for the operator, familiar accelerator controls; knowledge of acquisition phases during development must acknowledge the expert's mental model of machine operation; and automated operations must be seen as improvements to the operator's environment rather than threats of ultimate replacement. Experiences with the PACES Accelerator Operator Companion developed at two sites over the past three years are related and graphical examples are given. The scale of the work involves multi-computer control of various start-up/shutdown and tuning procedures for Model FN and KN Van de Graaff accelerators. The response from licensing agencies has been encouraging.

Nonsense-mediated mRNA decay: inter-individual variability and human disease

PubMed Central

Nguyen, Lam Son; Wilkinson, Miles; Gecz, Jozef

2013-01-01

Nonsense-Mediated mRNA Decay (NMD) is a regulatory pathway that functions to degrade transcripts containing premature termination codons (PTCs) and to maintain normal transcriptome homeostasis. Nonsense and frameshift mutations that generate PTCs cause approximately one-third of all known human genetic diseases and thus NMD has a potentially important role in human disease. In genetic disorders in which the affected genes carry PTC-generating mutations, NMD acts as a double-edge sword. While it can benefit the patient by degrading PTC-containing mRNAs that encode detrimental, dominant-negative truncated proteins, it can also make the disease worse when a PTC-containing mRNA is degraded that encodes a mutant but still functional protein. There is evidence that the magnitude of NMD varies between individuals, which, in turn, has been shown to correlate with both clinical presentations and the patients’ responses to drugs that promote read-through of PTCs. In this review, we examine the evidence supporting the existence of inter-individual variability in NMD efficiency and discuss the genetic factors that underlie this variability. We propose that inter-individual variability in NMD efficiency is a common phenomenon in human populations and that an individual’s NMD efficiency should be taken into consideration when testing, developing, and making therapeutic decisions for diseases caused by genes harboring PTCs. PMID:24239855

Differential Decay of Bacterial and Viral Fecal Indicators in Common Human Pollution Sources

EPA Science Inventory

Understanding the decomposition of different human fecal pollution sources is necessary for proper implementation of many water quality management practices, as well as predicting associated public health risks. Here, the decay of select cultivated and molecular indicators of fe...

Study of QCD-dynamics in η and η' production and decays

NASA Astrophysics Data System (ADS)

Beck, Reinhard; Wiedner, Ulrich

2017-01-01

One aim of this project lies in studying QCD dynamics using photoproduction of η and η' mesons with the CBELSA/TAPS experiment at the accelerator facility ELSA. Hadronic decay modes of η and η' are analyzed that allow the study of symmetry breaking effects in QCD. Furthermore, excited η-states produced with a photon beam are studied within the scope of this project. Of special interest is hereby the nature of the η(1405). The high data samples for η- and η'-photoproduction off the proton allow in addition the determination of polarization observables.

Top quarks at the Tevatron: Measurements of the top quark production and decay with the D0 experiment

DOE Office of Scientific and Technical Information (OSTI.GOV)

Strandberg, Jonas

2006-01-01

This thesis presents two measurements of the to pquark using 230 pb -1 of data recorded with the D0 detector at the Tevatron accelerator. The first measurement determines the top pair production cross section at √s = 1.96 TeV in proton-antiproton collisions. In the standard model of particle physics the top quark decays almost exclusively into a W boson and a b quark. Candidate events are selected by requiring that at least one jet in the event is tagged with the secondary vertex algorithm.

Photon Tagger Timing Calibration for the Rad Phi Experiment

NASA Astrophysics Data System (ADS)

Russell, Mammei; Smith, Elton

2000-10-01

Vector mesons provide a rich laboratory for the study of fundamental physics and radiative decays probe the very nature of the internal structure of these mesons, which possess the same quantum numbers of photons. Experiment E94-016, which collected data this past summer in Hall B of the Thomas Jefferson National Accelerator Facility (JLab), has measured the the branching ratios for rare radiative decays of the phi meson, i.e. φarrow f_0(975)γ arrow π^0π^0γ, φ arrow a_0(980)γ arrow π0 η γ, and φ arrow η'γ. A lead glass calorimeter, in concert with several detectors, measured these decays. A tagged beam of bremsstrahlung photons was directed upon a solid Beryllium target. A three-level trigger was then employed to preferentially select radiative decays of the φ meson. We calibrated timing of each detector by referencing individual detectors to one another. Tight timing will enhance signal relative to background.

Human Vitamin B12 Absorption and Metabolism are Measured by Accelerator Mass Spectrometry Using Specifically Labeled 14C-Cobalamin

DOE Office of Scientific and Technical Information (OSTI.GOV)

Carkeet, C; Dueker, S R; Lango, J

2006-01-26

There is need for an improved test of human ability to assimilate dietary vitamin B{sub 12}. Assaying and understanding absorption and uptake of B{sub 12} is important because defects can lead to hematological and neurological complications. Accelerator mass spectrometry (AMS) is uniquely suited for assessing absorption and kinetics of {sup 14}C-labeled substances after oral ingestion because it is more sensitive than decay counting and can measure levels of carbon-14 ({sup 14}C) in microliter volumes of biological samples, with negligible exposure of subjects to radioactivity. The test we describe employs amounts of B{sub 12} in the range of normal dietary intake.more » The B{sub 12} used was quantitatively labeled with {sup 14}C at one particular atom of the DMB moiety by exploiting idiosyncrasies of Salmonellametabolism. In order to grow aerobically on ethanolamine, S. entericamust be provided with either pre-formed B{sub 12} or two of its precursors: cobinamide and dimethylbenzimidazole (DMB). When provided with {sup 14}C-DMB specifically labeled in the C2 position, cells produced {sup 14}C-B{sub 12} of high specific activity (2.1 GBq/mmol, 58 mCi/mmol) and no detectable dilution of label from endogenous DMB synthesis. In a human kinetic study, a physiological dose (1.5 mg, 2.2 KBq/59 nCi) of purified {sup 14}C-B{sub 12} was administered and showed plasma appearance and clearance curves consistent with the predicted behavior of the pure vitamin. This method opens new avenues for study of B{sub 12} assimilation.« less

Ambient particulate matter accelerates coagulation via an IL-6-dependent pathway

EPA Science Inventory

The mechanisms by which exposure to particulate matter increases the risk of cardiovascular events are not known. Recent human and animal data suggest that particulate matter may induce alterations in hemostatic factors. In this study we determined the mechanisms by which particu...

Neutral Orbital Altitude Density Effects on the International Space Station

NASA Technical Reports Server (NTRS)

Smith, O.E.; Adelfang, S. I.; Smith, R. E.

1997-01-01

One of the design requirements of the International Space Station (ISS) is that each year accelerations of one micro-g cannot be exceeded at the ISS internal payload location for 6 periods of not less than 30 consecutive days. Although there are other causes, this study deals only with the accelerations caused by atmospheric drag. The critical ambient neutral density, computed using the Marshall Engineering Thermosphere Model, required to produce accelerations of one micro-g on the ISS, is estimated using an atmospheric drag acceleration equation. Results show that the design requirements may be difficult to meet during periods of extremely high solar activity; the planned reboost and altitude strategies for the ISS may have to be revised to allow for the uncertainty in the prediction of neutral atmospheric density within the 100-day period established for orbital decay before reboost.

The Human T-Lymphotropic Virus Type 1 Tax Protein Inhibits Nonsense-Mediated mRNA Decay by Interacting with INT6/EIF3E and UPF1

PubMed Central

Mocquet, Vincent; Neusiedler, Julia; Rende, Francesca; Cluet, David; Robin, Jean-Philippe; Terme, Jean-Michel; Duc Dodon, Madeleine; Wittmann, Jürgen; Morris, Christelle; Le Hir, Hervé; Ciminale, Vincenzo

2012-01-01

In this report, we analyzed whether the degradation of mRNAs by the nonsense-mediated mRNA decay (NMD) pathway was affected in human T-lymphotropic virus type 1 (HTLV-1)-infected cells. This pathway was indeed strongly inhibited in C91PL, HUT102, and MT2 cells, and such an effect was also observed by the sole expression of the Tax protein in Jurkat and HeLa cells. In line with this activity, Tax binds INT6/EIF3E (here called INT6), which is a subunit of the translation initiation factor eukaryotic initiation factor 3 (eIF3) required for efficient NMD, as well as the NMD core factor upstream frameshift protein 1 (UPF1). It was also observed that Tax expression alters the morphology of processing bodies (P-bodies), the cytoplasmic structures which concentrate RNA degradation factors. The presence of UPF1 in these subcellular compartments was increased by Tax, whereas that of INT6 was decreased. In line with these effects, the level of the phosphorylated form of UPF1 was increased in the presence of Tax. Analysis of several mutants of the viral protein showed that the interaction with INT6 is necessary for NMD inhibition. The alteration of mRNA stability was observed to affect viral transcripts, such as that coding for the HTLV-1 basic leucine zipper factor (HBZ), and also several cellular mRNAs sensitive to the NMD pathway. Our data indicate that the effect of Tax on viral and cellular gene expression is not restricted to transcriptional control but can also involve posttranscriptional regulation. PMID:22553336

Time arrow is influenced by the dark energy.

PubMed

Allahverdyan, A E; Gurzadyan, V G

2016-05-01

The arrow of time and the accelerated expansion are two fundamental empirical facts of the universe. We advance the viewpoint that the dark energy (positive cosmological constant) accelerating the expansion of the universe also supports the time asymmetry. It is related to the decay of metastable states under generic perturbations, as we show on example of a microcanonical ensemble. These states will not be metastable without dark energy. The latter also ensures a hyperbolic motion leading to dynamic entropy production with the rate determined by the cosmological constant.

Xylitol chewing gum and dental caries.

PubMed

Tanzer, J M

1995-02-01

There is an extensive peer-reviewed literature on xylitol chewing gum as it pertains to effects on tooth decay in human subjects, on human dental plaque reduction, on inhibition of dental plaque acid production, on inhibition of the growth and metabolism of the mutans group of streptococci which are the prime causative agents of tooth decay, on reduction of tooth decay in experimental animals, and on xylitol's reported contribution to the remineralisation of teeth. The literature not only supports the conclusion that xylitol is non-cariogenic but it is now strongly suggestive that xylitol is caries inhibitory, that is, anti-cariogenic in human subjects, and it supplies reasonable mechanistic explanation(s).

Precision Light Flavor Physics from Lattice QCD

NASA Astrophysics Data System (ADS)

Murphy, David

In this thesis we present three distinct contributions to the study of light flavor physics using the techniques of lattice QCD. These results are arranged into four self-contained papers. The first two papers concern global fits of the quark mass, lattice spacing, and finite volume dependence of the pseudoscalar meson masses and decay constants, computed in a series of lattice QCD simulations, to partially quenched SU(2) and SU(3) chiral perturbation theory (chiPT). These fits determine a subset of the low energy constants of chiral perturbation theory -- in some cases with increased precision, and in other cases for the first time -- which, once determined, can be used to compute other observables and amplitudes in chiPT. We also use our formalism to self-consistently probe the behavior of the (asymptotic) chiral expansion as a function of the quark masses by repeating the fits with different subsets of the data. The third paper concerns the first lattice QCD calculation of the semileptonic K0 → pi-l +nul ( Kl3) form factor at vanishing momentum transfer, f+Kpi(0), with physical mass domain wall quarks. The value of this form factor can be combined with a Standard Model analysis of the experimentally measured K0 → pi -l+nu l decay rate to extract a precise value of the Cabibbo-Kobayashi-Maskawa (CKM) matrix element Vus, and to test unitarity of the CKM matrix. We also discuss lattice calculations of the pion and kaon decay constants, which can be used to extract Vud through an analogous Standard Model analysis of experimental constraints on leptonic pion and kaon decays. The final paper explores the recently proposed exact one flavor algorithm (EOFA). This algorithm has been shown to drastically reduce the memory footprint required to simulate single quark flavors on the lattice relative to the widely used rational hybrid Monte Carlo (RHMC) algorithm, while also offering modest O(20%) speed-ups. We independently derive the exact one flavor action, explore its equivalence to the RHMC action, and demonstrate that additional preconditioning techniques can be used to significantly accelerate EOFA simulations. We apply EOFA to the ongoing RBC/UKQCD calculation of the Delta I = 1/2 K → pipi decay amplitude, and demonstrate that, in this context, gauge field configurations can be generated a factor of 4.2 times faster using an EOFA-based simulation rather than the previous RHMC-based simulations. We expect that EOFA will help to significantly reduce the statistical error in the first-principles determination of the Standard Model CP-violation parameters epsilon and epsilon' offered by the K → pipi calculation.

Gating current studies reveal both intra- and extracellular cation modulation of K+ channel deactivation

PubMed Central

Wang, Zhuren; Zhang, Xue; Fedida, David

1999-01-01

The presence of permeant ions can modulate the rate of gating charge return in wild-type human heart K+ (hKv1.5) channels. Here we employ gating current measurements in a non-conducting mutant, W472F, of the hKv1.5 channel to investigate how different cations can modulate charge return and whether the actions can be specifically localized at the internal as well as the external mouth of the channel pore. Intracellular cations were effective at accelerating charge return in the sequence Cs+ > Rb+ > K+ > Na+ > NMG+. Extracellular cations accelerated charge return with the selectivity sequence Cs+ > Rb+ > Na+ = NMG+. Intracellular and extracellular cation actions were of relatively low affinity. The Kd for preventing slowing of the time constant of the off-gating current decay (τoff) was 20.2 mM for intracellular Cs+ (Csi+) and 358 mM for extracellular Cs+ (Cso+). Both intracellular and extracellular cations can regulate the rate of charge return during deactivation of hKv1.5, but intracellular cations are more effective. We suggest that ion crystal radius is an important determinant of this action, with larger ions preventing slowing more effectively. Important parallels exist with cation-dependent modulation of slow inactivation of ionic currents in this channel. However, further experiments are required to understand the exact relationship between acceleration of charge return and the slowing of inactivation of ionic currents by cations. PMID:10050001

Pyroclast acceleration and energy partitioning in fake explosive eruptions

NASA Astrophysics Data System (ADS)

Gaudin, Damien; Taddeucci, Jacopo; Scheu, Bettina; Valentine, Greg; Capponi, Antonio; Kueppers, Ulrich; Graettiger, Allison; Sonder, Ingo

2014-05-01

Explosive eruptions are characterized by the fast release of energy, with gas expansion playing a lead role. An excess of pressure may be generated either by the exsolution and accumulation of volatiles (e.g., vulcanian and strombolian explosions) or by in situ vaporization of water (e.g., phreato-magmatic explosions). The release of pressurized gas ejects magma and country rock pyroclasts at velocities that can reach several hundred of meters per second. The amount and velocity of pyroclasts is determined not only by the total released energy, but also by the system-specific dynamics of the energy transfer from gas to pyroclasts. In this context, analogue experiments are crucial, since the amount of available energy is determined. Here, we analyze three different experiments, designed to reproduce different aspects of explosive volcanism, focusing on the acceleration phase of the pyroclasts, in order to compare how the potential energy is transferred to the pyroclasts in different systems. In the first, shock-tube-type experiment, salt crystals resting in a pressurized Plexiglas cylinder are accelerated when a diaphragm set is suddenly opened, releasing the gas. In the second experiment, a pressurized air bubble is released in a water-filled Plexiglas pipe; diaphragm opening causes sudden expansion and bursting of the bubble and ejection of water droplets. In the last experiment, specifically focusing on phreatomagmatic eruptions, buried explosive charges accelerate the overlying loose material. All experiments were monitored by multiple high speed cameras and a variety of sensors. Despite the largely differing settings and processes, particle ejection velocity above the vent from the three experiments share a non-linear decay over time. Fitting this decay allows to estimate a characteristic depth that is related to the specific acceleration processes. Given that the initial available energy is experimentally controlled a priori, the information on the acceleration processes (and related kinetic energy) can be used to brings new constraints on the energy partition and general pyroclasts ejection mechanisms during eruptions.

Power spectrum analyses of nuclear decay rates

NASA Astrophysics Data System (ADS)

Javorsek, D.; Sturrock, P. A.; Lasenby, R. N.; Lasenby, A. N.; Buncher, J. B.; Fischbach, E.; Gruenwald, J. T.; Hoft, A. W.; Horan, T. J.; Jenkins, J. H.; Kerford, J. L.; Lee, R. H.; Longman, A.; Mattes, J. J.; Morreale, B. L.; Morris, D. B.; Mudry, R. N.; Newport, J. R.; O'Keefe, D.; Petrelli, M. A.; Silver, M. A.; Stewart, C. A.; Terry, B.

2010-10-01

We provide the results from a spectral analysis of nuclear decay data displaying annually varying periodic fluctuations. The analyzed data were obtained from three distinct data sets: 32Si and 36Cl decays reported by an experiment performed at the Brookhaven National Laboratory (BNL), 56Mn decay reported by the Children's Nutrition Research Center (CNRC), but also performed at BNL, and 226Ra decay reported by an experiment performed at the Physikalisch-Technische Bundesanstalt (PTB) in Germany. All three data sets exhibit the same primary frequency mode consisting of an annual period. Additional spectral comparisons of the data to local ambient temperature, atmospheric pressure, relative humidity, Earth-Sun distance, and their reciprocals were performed. No common phases were found between the factors investigated and those exhibited by the nuclear decay data. This suggests that either a combination of factors was responsible, or that, if it was a single factor, its effects on the decay rate experiments are not a direct synchronous modulation. We conclude that the annual periodicity in these data sets is a real effect, but that further study involving additional carefully controlled experiments will be needed to establish its origin.

Experimental tests of factorization in charmless nonleptonic two-body B decays

NASA Astrophysics Data System (ADS)

Ali, A.; Kramer, G.; Lü, Cai-Dian

1998-11-01

Using a theoretical framework based on the next-to-leading-order QCD-improved effective Hamiltonian and a factorization ansatz for the hadronic matrix elements of the four-quark operators, we reassess branching fractions in two-body nonleptonic decays B-->PP,PV,VV, involving the lowest-lying light pseudoscalar (P) and vector (V) mesons in the standard model. We work out the parametric dependence of the decay rates, making use of the currently available information on the weak mixing matrix elements, form factors, decay constants, and quark masses. Using the sensitivity of the decay rates on the effective number of colors, Nc, as a criterion of theoretical predictivity, we classify all the current-current (tree) and penguin transitions in five different classes. The recently measured charmless two-body B-->PP decays (B+-->K+η', B0-->K0η', B0-->K+π-, B+-->π+K0, and charge conjugates) are dominated by the Nc-stable QCD penguin transitions (class-IV transitions) and their estimates are consistent with the data. The measured charmless B-->PV (B+-->ωK+, B+-->ωh+) and B-->VV transition (B-->φK*), on the other hand, belong to the penguin (class-V) and tree (class-III) transitions. The class-V penguin transitions are Nc sensitive and/or involve large cancellations among competing amplitudes, making their decay rates in general more difficult to predict. Some of these transitions may also receive significant contributions from annihilation and/or final state interactions. We propose a number of tests of the factorization framework in terms of the ratios of branching ratios for some selected B-->h1h2 decays involving light hadrons h1 and h2, which depend only moderately on the form factors. We also propose a set of measurements to determine the effective coefficients of the current-current and QCD penguin operators. The potential impact of B-->h1h2 decays on the CKM phenomenology is emphasized by analyzing a number of decay rates in the factorization framework.

Photoproduction and Radiative Decay of η' Meson in CLAS at Jlab

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mbianda Njencheu, Georgie

In this work the η' meson photoproduction cross sections as well as the distribution of the di-pion invariant mass, m(π+π-), in the radiative decay mode n' -> π+π-γ have been measured using the CLAS detector at the Thomas Jefferson National Accelerator Facility using tagged incident photons in the center-of-mass energy range 1.96 GeV - 2.72 GeV. The measurements are performed on a liquid hydrogen target in the reaction γ π -> π η'(η'-> π+π-γ). The analysis is based on the highest statistics collected in this decay channel in comparison to other experiments reported so far. The n' photoproduction cross sectionsmore » measured with radiative decay are in a good agreement with results of previous publication from the same data set in CLAS obtained through η' -> π+π-γ decay mode. Two free parameters, α and Β, are extracted from a model-independent fit to the m(π+π-) distribution and their values are found to agree well with recent theoretical expectations. The results of both parameters confirm the existence of the box anomaly, ρ-ω mixing and effects of the a2(1320) tensor meson in the radiative decay of η'.« less

Why Does Attention to Web Articles Fall With Time?

PubMed

Simkin, Mikhail V; Roychowdhury, Vwani P

2015-09-01

We analyze access statistics of 150 blog entries and news articles for periods of up to 3 years. Access rate falls as an inverse power of time passed since publication. The power law holds for periods of up to 1,000 days. The exponents are different for different blogs and are distributed between 0.6 and 3.2. We argue that the decay of attention to a web article is caused by the link to it first dropping down the list of links on the website's front page and then disappearing from the front page and its subsequent movement further into background. The other proposed explanations that use a decaying with time novelty factor, or some intricate theory of human dynamics, cannot explain all of the experimental observations.

Photoproduction of ω mesons off protons and neutrons

NASA Astrophysics Data System (ADS)

Dietz, F.; Metag, V.; Anisovich, A. V.; Bacelar, J. C. S.; Bantes, B.; Bartholomy, O.; Bayadilov, D. E.; Beck, R.; Belogazov, Y. A.; Castelijns, R.; Crede, V.; Dutz, H.; Elsner, D.; Ewald, R.; Frommberger, F.; Funke, C.; Gothe, R.; Gregor, R.; Gridnev, A. B.; Gutz, E.; Hillert, W.; Höffgren, S.; Hoffmeister, P.; Horn, I.; Jaegle, I.; Junkersfeld, J.; Kalinowsky, H.; Kammer, S.; Kleber, V.; Klein, Frank; Klein, Friedrich; Klempt, E.; Konrad, M.; Kotulla, M.; Krusche, B.; Lang, M.; Löhner, H.; Lopatin, I. V.; Lugert, S.; Menze, D.; Mertens, T.; Messchendorp, J. G.; Nikonov, V. A.; Nanova, M.; Novinski, D. V.; Novotny, R.; Ostrick, M.; Pant, L. M.; van Pee, H.; Pfeiffer, M.; Rostomyan, T.; Roy, A.; Schadmand, S.; Schmidt, C.; Schmieden, H.; Schoch, B.; Shende, S. V.; Shklyar, V.; Süle, A.; Sumachev, V. V.; Szczepanek, T.; Thoma, U.; Trnka, D.; Varma, R.; Walter, D.; Wendel, C.; Wilson, A.

2015-01-01

ω photoproduction off hydrogen and deuterium has been studied with the tagged photon beam of the ELSA accelerator in Bonn for photon energies up to 2.0 GeV. The ω meson has been identified via the ω → π0 γ → γγγ decay mode, using the combined setup of the Crystal Barrel/TAPS detector systems. Both inclusive and exclusive analyses have been carried out. Differential and total cross-sections have been derived for ω mesons produced off free protons and off protons and neutrons bound in deuterium. The cross-section for the production off the bound neutron is found to be a factor of ≈ 1.3 larger than the one off the bound proton in the incident beam energy region 1.2 GeV < E γ < 1.6 GeV. For higher incident beam energies this factor goes down to ≈ 1.1 at 2.0 GeV. The cross-sections of this work have been used as normalization for transparency ratio measurements.

SHORT ACCELERATION TIMES FROM SUPERDIFFUSIVE SHOCK ACCELERATION IN THE HELIOSPHERE

DOE Office of Scientific and Technical Information (OSTI.GOV)

Perri, S.; Zimbardo, G., E-mail: silvia.perri@fis.unical.it

2015-12-10

The analysis of time profiles of particles accelerated at interplanetary shocks allows particle transport properties to be inferred. The frequently observed power-law decay upstream, indeed, implies a superdiffusive particle transport when the level of magnetic field variance does not change as the time interval from the shock front increases. In this context, a superdiffusive shock acceleration (SSA) theory has been developed, allowing us to make predictions of the acceleration times. In this work we estimate for a number of interplanetary shocks, including the solar wind termination shock, the acceleration times for energetic protons in the framework of SSA and wemore » compare the results with the acceleration times predicted by standard diffusive shock acceleration. The acceleration times due to SSA are found to be much shorter than in the classical model, and also shorter than the interplanetary shock lifetimes. This decrease of the acceleration times is due to the scale-free nature of the particle displacements in the framework of superdiffusion. Indeed, very long displacements are possible, increasing the probability for particles far from the front of the shock to return, and short displacements have a high probability of occurrence, increasing the chances for particles close to the front to cross the shock many times.« less

Measurement of |V(cb)| and the form-factor slope in B --> Dl- nu(l) decays in events tagged by a fully reconstructed B meson.

PubMed

Aubert, B; Karyotakis, Y; Lees, J P; Poireau, V; Prencipe, E; Prudent, X; Tisserand, V; Garra Tico, J; Grauges, E; Martinelli, M; Palano, A; Pappagallo, M; Eigen, G; Stugu, B; Sun, L; Battaglia, M; Brown, D N; Kerth, L T; Kolomensky, Yu G; Lynch, G; Osipenkov, I L; Tackmann, K; Tanabe, T; Hawkes, C M; Soni, N; Watson, A T; Koch, H; Schroeder, T; Asgeirsson, D J; Fulsom, B G; Hearty, C; Mattison, T S; McKenna, J A; Barrett, M; Khan, A; Randle-Conde, A; Blinov, V E; Bukin, A D; Buzykaev, A R; Druzhinin, V P; Golubev, V B; Onuchin, A P; Serednyakov, S I; Skovpen, Yu I; Solodov, E P; Todyshev, K Yu; Bondioli, M; Curry, S; Eschrich, I; Kirkby, D; Lankford, A J; Lund, P; Mandelkern, M; Martin, E C; Stoker, D P; Atmacan, H; Gary, J W; Liu, F; Long, O; Vitug, G M; Yasin, Z; Zhang, L; Sharma, V; Campagnari, C; Hong, T M; Kovalskyi, D; Mazur, M A; Richman, J D; Beck, T W; Eisner, A M; Heusch, C A; Kroseberg, J; Lockman, W S; Martinez, A J; Schalk, T; Schumm, B A; Seiden, A; Wang, L; Winstrom, L O; Cheng, C H; Doll, D A; Echenard, B; Fang, F; Hitlin, D G; Narsky, I; Piatenko, T; Porter, F C; Andreassen, R; Mancinelli, G; Meadows, B T; Mishra, K; Sokoloff, M D; Bloom, P C; Ford, W T; Gaz, A; Hirschauer, J F; Nagel, M; Nauenberg, U; Smith, J G; Wagner, S R; Ayad, R; Toki, W H; Wilson, R J; Feltresi, E; Hauke, A; Jasper, H; Karbach, T M; Merkel, J; Petzold, A; Spaan, B; Wacker, K; Kobel, M J; Nogowski, R; Schubert, K R; Schwierz, R; Volk, A; Bernard, D; Latour, E; Verderi, M; Clark, P J; Playfer, S; Watson, J E; Andreotti, M; Bettoni, D; Bozzi, C; Calabrese, R; Cecchi, A; Cibinetto, G; Fioravanti, E; Franchini, P; Luppi, E; Munerato, M; Negrini, M; Petrella, A; Piemontese, L; Santoro, V; Baldini-Ferroli, R; Calcaterra, A; de Sangro, R; Finocchiaro, G; Pacetti, S; Patteri, P; Peruzzi, I M; Piccolo, M; Rama, M; Zallo, A; Contri, R; Guido, E; Lo Vetere, M; Monge, M R; Passaggio, S; Patrignani, C; Robutti, E; Tosi, S; Chaisanguanthum, K S; Morii, M; Adametz, A; Marks, J; Schenk, S; Uwer, U; Bernlochner, F U; Klose, V; Lacker, H M; Bard, D J; Dauncey, P D; Tibbetts, M; Behera, P K; Charles, M J; Mallik, U; Cochran, J; Crawley, H B; Dong, L; Eyges, V; Meyer, W T; Prell, S; Rosenberg, E I; Rubin, A E; Gao, Y Y; Gritsan, A V; Guo, Z J; Arnaud, N; Béquilleux, J; D'Orazio, A; Davier, M; Derkach, D; da Costa, J Firmino; Grosdidier, G; Le Diberder, F; Lepeltier, V; Lutz, A M; Malaescu, B; Pruvot, S; Roudeau, P; Schune, M H; Serrano, J; Sordini, V; Stocchi, A; Wormser, G; Lange, D J; Wright, D M; Bingham, I; Burke, J P; Chavez, C A; Fry, J R; Gabathuler, E; Gamet, R; Hutchcroft, D E; Payne, D J; Touramanis, C; Bevan, A J; Clarke, C K; Di Lodovico, F; Sacco, R; Sigamani, M; Cowan, G; Paramesvaran, S; Wren, A C; Brown, D N; Davis, C L; Denig, A G; Fritsch, M; Gradl, W; Hafner, A; Alwyn, K E; Bailey, D; Barlow, R J; Jackson, G; Lafferty, G D; West, T J; Yi, J I; Anderson, J; Chen, C; Jawahery, A; Roberts, D A; Simi, G; Tuggle, J M; Dallapiccola, C; Salvati, E; Saremi, S; Cowan, R; Dujmic, D; Fisher, P H; Henderson, S W; Sciolla, G; Spitznagel, M; Yamamoto, R K; Zhao, M; Patel, P M; Robertson, S H; Schram, M; Lazzaro, A; Lombardo, V; Palombo, F; Stracka, S; Bauer, J M; Cremaldi, L; Godang, R; Kroeger, R; Sonnek, P; Summers, D J; Zhao, H W; Simard, M; Taras, P; Nicholson, H; De Nardo, G; Lista, L; Monorchio, D; Onorato, G; Sciacca, C; Raven, G; Snoek, H L; Jessop, C P; Knoepfel, K J; LoSecco, J M; Wang, W F; Corwin, L A; Honscheid, K; Kagan, H; Kass, R; Morris, J P; Rahimi, A M; Regensburger, J J; Sekula, S J; Wong, Q K; Blount, N L; Brau, J; Frey, R; Igonkina, O; Kolb, J A; Lu, M; Rahmat, R; Sinev, N B; Strom, D; Strube, J; Torrence, E; Castelli, G; Gagliardi, N; Margoni, M; Morandin, M; Posocco, M; Rotondo, M; Simonetto, F; Stroili, R; Voci, C; Sanchez, P del Amo; Ben-Haim, E; Bonneaud, G R; Briand, H; Chauveau, J; Hamon, O; Leruste, Ph; Marchiori, G; Ocariz, J; Perez, A; Prendki, J; Sitt, S; Gladney, L; Biasini, M; Manoni, E; Angelini, C; Batignani, G; Bettarini, S; Calderini, G; Carpinelli, M; Cervelli, A; Forti, F; Giorgi, M A; Lusiani, A; Morganti, M; Neri, N; Paoloni, E; Rizzo, G; Walsh, J J; Pegna, D Lopes; Lu, C; Olsen, J; Smith, A J S; Telnov, A V; Anulli, F; Baracchini, E; Cavoto, G; Faccini, R; Ferrarotto, F; Ferroni, F; Gaspero, M; Jackson, P D; Gioi, L Li; Mazzoni, M A; Morganti, S; Piredda, G; Renga, F; Voena, C; Ebert, M; Hartmann, T; Schröder, H; Waldi, R; Adye, T; Franek, B; Olaiya, E O; Wilson, F F; Emery, S; Esteve, L; de Monchenault, G Hamel; Kozanecki, W; Vasseur, G; Yèche, Ch; Zito, M; Allen, M T; Aston, D; Bartoldus, R; Benitez, J F; Cenci, R; Coleman, J P; Convery, M R; Dingfelder, J C; Dorfan, J; Dubois-Felsmann, G P; Dunwoodie, W; Field, R C; Sevilla, M Franco; Gabareen, A M; Graham, M T; Grenier, P; Hast, C; Innes, W R; Kaminski, J; Kelsey, M H; Kim, H; Kim, P; Kocian, M L; Leith, D W G S; Li, S; Lindquist, B; Luitz, S; Luth, V; Lynch, H L; MacFarlane, D B; Marsiske, H; Messner, R; Muller, D R; Neal, H; Nelson, S; O'Grady, C P; Ofte, I; Perl, M; Ratcliff, B N; Roodman, A; Salnikov, A A; Schindler, R H; Schwiening, J; Snyder, A; Su, D; Sullivan, M K; Suzuki, K; Swain, S K; Thompson, J M; Va'vra, J; Wagner, A P; Weaver, M; West, C A; Wisniewski, W J; Wittgen, M; Wright, D H; Wulsin, H W; Yarritu, A K; Young, C C; Ziegler, V; Chen, X R; Liu, H; Park, W; Purohit, M V; White, R M; Wilson, J R; Burchat, P R; Edwards, A J; Miyashita, T S; Ahmed, S; Alam, M S; Ernst, J A; Pan, B; Saeed, M A; Zain, S B; Soffer, A; Spanier, S M; Wogsland, B J; Eckmann, R; Ritchie, J L; Ruland, A M; Schilling, C J; Schwitters, R F; Wray, B C; Drummond, B W; Izen, J M; Lou, X C; Bianchi, F; Gamba, D; Pelliccioni, M; Bomben, M; Bosisio, L; Cartaro, C; Della Ricca, G; Lanceri, L; Vitale, L; Azzolini, V; Lopez-March, N; Martinez-Vidal, F; Milanes, D A; Oyanguren, A; Albert, J; Banerjee, Sw; Bhuyan, B; Choi, H H F; Hamano, K; King, G J; Kowalewski, R; Lewczuk, M J; Nugent, I M; Roney, J M; Sobie, R J; Gershon, T J; Harrison, P F; Ilic, J; Latham, T E; Mohanty, G B; Puccio, E M T; Band, H R; Chen, X; Dasu, S; Flood, K T; Pan, Y; Prepost, R; Vuosalo, C O; Wu, S L

2010-01-08

We present a measurement of the Cabibbo-Kobayashi-Maskawa matrix element |V(cb)| and the form-factor slope rho2 in B --> Dl- nu(l) decays based on 460x10(6) BB events recorded at the Upsilon(4S) resonance with the BABAR detector. B --> Dl- nu(l) decays are selected in events in which a hadronic decay of the second B meson is fully reconstructed. We measure B(B- --> D0 l- nu(l))/B(B- --> Xl- nu(l)) = (0.255+/-0.009+/-0.009) and B(B0 --> D+ l- nu(l))/B(B0 --> Xl- nu(l)) = (0.230+/-0.011+/-0.011), along with the differential decay distribution in B --> Dl- nu(l) decays. We then determine G(1)|V(cb)| = (42.3+/-1.9+/-1.4)x10(-3) and rho2 = 1.20+/-0.09+/-0.04, where G(1) is the hadronic form factor at the point of zero recoil.

Hydrodynamic growth and decay of planar shock waves

DOE Office of Scientific and Technical Information (OSTI.GOV)

Piriz, A. R., E-mail: roberto.piriz@uclm.es; Sun, Y. B.; Tahir, N. A.

2016-03-15

A model for the hydrodynamic attenuation (growth and decay) of planar shocks is presented. The model is based on the approximate integration of the fluid conservation equations, and it does not require the heuristic assumptions used in some previous works. A key issue of the model is that the boundary condition on the piston surface is given by the retarded pressure, which takes into account the transit time of the sound waves between the piston and any position at the bulk of the shocked fluid. The model yields the shock pressure evolution for any given pressure pulse on the piston,more » as well as the evolution of the trajectories, velocities, and accelerations on the shock and piston surfaces. An asymptotic analytical solution is also found for the decay of the shock wave.« less

Factors and processes causing accelerated decomposition in human cadavers - An overview.

PubMed

Zhou, Chong; Byard, Roger W

2011-01-01

Artefactually enhanced putrefactive and autolytic changes may be misinterpreted as indicating a prolonged postmortem interval and throw doubt on the veracity of witness statements. Review of files from Forensic Science SA and the literature revealed a number of external and internal factors that may be responsible for accelerating these processes. Exogenous factors included exposure to elevated environmental temperatures, both outdoors and indoors, exacerbated by increased humidity or fires. Situations indoor involved exposure to central heating, hot water, saunas and electric blankets. Deaths within motor vehicles were also characterized by enhanced decomposition. Failure to quickly or adequately refrigerate bodies may also lead to early decomposition. Endogenous factors included fever, infections, illicit and prescription drugs, obesity and insulin-dependent diabetes mellitus. When these factors or conditions are identified at autopsy less significance should, therefore, be attached to changes of decomposition as markers of time since death. Copyright © 2010 Elsevier Ltd and Faculty of Forensic and Legal Medicine. All rights reserved.

Analysis of Environmental Stress Factors Using an Artificial Growth System and Plant Fitness Optimization

PubMed Central

Lee, Meonghun; Yoe, Hyun

2015-01-01

The environment promotes evolution. Evolutionary processes represent environmental adaptations over long time scales; evolution of crop genomes is not inducible within the relatively short time span of a human generation. Extreme environmental conditions can accelerate evolution, but such conditions are often stress inducing and disruptive. Artificial growth systems can be used to induce and select genomic variation by changing external environmental conditions, thus, accelerating evolution. By using cloud computing and big-data analysis, we analyzed environmental stress factors for Pleurotus ostreatus by assessing, evaluating, and predicting information of the growth environment. Through the indexing of environmental stress, the growth environment can be precisely controlled and developed into a technology for improving crop quality and production. PMID:25874206

Biological basis of neuroprotection and neurotherapeutic effects of Whole Body Periodic Acceleration (pGz).

PubMed

Adams, Jose A; Uryash, Arkady; Bassuk, Jorge; Sackner, Marvin A; Kurlansky, Paul

2014-06-01

Exercise is a well known neuroprotective and neurotherapeutic strategy in animal models and humans with brain injury and cognitive dysfunction. In part, exercise induced beneficial effects relate to endothelial derived nitric oxide (eNO) production and induction of the neurotrophins; Brain Derived Neurotrophic Factor (BDNF) and Glial Derived Neurotrophic Factor (GDNF). Whole Body Periodic Acceleration (WBPA (pGz), is the motion of the supine body headward to footward in a sinusoidal fashion, at frequencies of 100-160 cycles/min, inducing pulsatile shear stress to the vascular endothelium. WBPA (pGz) increases eNO in the cardiovascular system in animal models and humans. We hypothesized that WBPA (pGz) has neuroprotective and neurotherapeutic effects due to enhancement of biological pathways that include eNOS, BDNF and GDNF. We discuss protein expression analysis of these in brain of rodents. Animal and observational human data affirm a neuroprotective and neurotherapeutic role for WBPA (pGz). These findings suggest that WBPA (pGz) in addition to its well known beneficial cardiovascular effects can be a simple non-invasive neuroprotective and neurotherapeutic strategy with far reaching health benefits. Copyright © 2014 Elsevier Ltd. All rights reserved.

Growth factors, nutrient signaling, and cardiovascular aging.

PubMed

Fontana, Luigi; Vinciguerra, Manlio; Longo, Valter D

2012-04-13

Growth factors regulated by specific macronutrients have been shown to promote aging and accelerate mortality in the majority of the organisms studied. In particular, the enzymes activated by growth hormone, insulin, and insulin-like growth factor-1 in mammals and their orthologs in simple model organisms represent perhaps the best-understood proteins involved in the aging process. Dietary restriction, which reduces the level of insulin-like growth factor-1 and of other growth factors, has been associated with protection from diabetes, cancer, and cardiovascular diseases, and deficiencies in growth hormone signaling and insulin-like growth factor-1 are strongly associated with protection from cancer and diabetes in both mice and humans; however, their role in cardiac function and cardiovascular diseases is controversial. Here, we review the link between growth factors, cardiac function, and heart disease with focus on the cardioprotective and sensitizing effect of growth factors in both model organisms and humans.

Charmless two-body B decays: A global analysis with QCD factorization

NASA Astrophysics Data System (ADS)

Du, Dongsheng; Sun, Junfeng; Yang, Deshan; Zhu, Guohuai

2003-01-01

In this paper, we perform a global analysis of B→PP and PV decays with the QCD factorization approach. It is encouraging to observe that the predictions of QCD factorization are in good agreement with experiment. The best fit γ is around 79 °. The penguin-diagram to tree-diagram ratio |Pππ/Tππ| of π+π- decays is preferred to be larger than 0.3. We also show the confidence levels for some interesting channels: B0→π0π0, K+K-, and B+→ωπ+, ωK+. For B→πK* decays, they are expected to have smaller branching ratios with more precise measurements.

Recent results of measurements of evaporation residue excitation functions for 19F+194,196,198Pt and 16,18O+198Pt systems with HYRA spectrometer at IUAC

NASA Astrophysics Data System (ADS)

Behera, B. R.

2015-01-01

In this talk results of the evaporation residue (ER) cross sections for the 19F+194,196,198Pt (forming compound nuclei 213,215,217Fr) and 16,18O+198Pt (forming compound nuclei 214,216Rn) systems measured at Hybrid Recoil mass Analyzer (HYRA) spectrometer installed at the Pelletron+LINAC accelerator facility of the Inter University Accelerator Center (IUAC), New Delhi are reported. The survival probabilities of 215Fr and 217Fr with neutron numbers N = 126 are found to be lower than the survival probabilities of 215Fr and 217Fr with neutron numbers N = 128 and 130 respectively. Statistical model analysis of the ER cross sections show that an excitation energy dependent scaling factor of the finite-range rotating liquid drop model fission barrier is necessary to fit the experimental data. For the case of 214,216Rn, the experimental ER cross sections are compared with the predictions from the statistical model calculations of compound nuclear decay where Kramer's fission width is used. The strength of nuclear dissipation is treated as a free parameter in the calculations to fit the experimental data.

Demographic, socioeconomic, and behavioral factors affecting patterns of tooth decay in the permanent dentition: Principal components and factor analyses

PubMed Central

Shaffer, John R.; Polk, Deborah E.; Feingold, Eleanor; Wang, Xiaojing; Cuenco, Karen T.; Weeks, Daniel E.; DeSensi, Rebecca S.; Weyant, Robert J.; Crout, Richard; McNeil, Daniel W.; Marazita, Mary L.

2012-01-01

Objectives Dental caries of the permanent dentition is a multi-factorial disease resulting from the complex interplay of endogenous and environmental risk factors. The disease is not easily quantified due to the innumerable possible combinations of carious lesions across individual tooth surfaces of the permanent dentition. Global measures of decay, such as the DMFS index (which was developed for surveillance applications), may not be optimal for studying the epidemiology of dental caries because they ignore the distinct patterns of decay across the dentition. We hypothesize that specific risk factors may manifest their effects on specific tooth surfaces leading to patterns of decay that can be identified and studied. In this study we utilized two statistical methods of extracting patterns of decay from surface-level caries data in order to create novel phenotypes with which to study the risk factors affecting dental caries. Methods Intra-oral dental examinations were performed on 1,068 participants aged 18 to 75 years to assess dental caries. The 128 tooth surfaces of the permanent dentition were scored as carious or not and used as input for principal components analysis (PCA) and factor analysis (FA), two methods of identifying underlying patterns without a priori knowledge of the patterns. Demographic (age, sex, birth year, race/ethnicity, and educational attainment), anthropometric (height, body mass index, waist circumference), endogenous (saliva flow), and environmental (tooth brushing frequency, home water source, and home water fluoride) risk factors were tested for association with the caries patterns identified by PCA and FA, as well as DMFS, for comparison. The ten strongest patterns (i.e., those that explain the most variation in the data set) extracted by PCA and FA were considered. Results The three strongest patterns identified by PCA reflected (i) global extent of decay (i.e., comparable to DMFS index), (ii) pit and fissure surface caries, and (iii) smooth surface caries, respectively. The two strongest patterns identified by FA corresponded to (i) pit and fissure surface caries and (ii) maxillary incisor caries. Age and birth year were significantly associated with several patterns of decay, including global decay/DMFS index. Sex, race, educational attainment, and tooth brushing were each associated with specific patterns of decay, but not with global decay/DMFS index. Conclusions Taken together, these results support the notion that caries experience is separable into patterns attributable to distinct risk factors. This study demonstrates the utility of such novel caries patterns as new outcomes for exploring the complex, multifactorial nature of dental caries. PMID:23106439

Demographic, socioeconomic, and behavioral factors affecting patterns of tooth decay in the permanent dentition: principal components and factor analyses.

PubMed

Shaffer, John R; Polk, Deborah E; Feingold, Eleanor; Wang, Xiaojing; Cuenco, Karen T; Weeks, Daniel E; DeSensi, Rebecca S; Weyant, Robert J; Crout, Richard; McNeil, Daniel W; Marazita, Mary L

2013-08-01

Dental caries of the permanent dentition is a multifactorial disease resulting from the complex interplay of endogenous and environmental risk factors. The disease is not easily quantitated due to the innumerable possible combinations of carious lesions across individual tooth surfaces of the permanent dentition. Global measures of decay, such as the DMFS index (which was developed for surveillance applications), may not be optimal for studying the epidemiology of dental caries because they ignore the distinct patterns of decay across the dentition. We hypothesize that specific risk factors may manifest their effects on specific tooth surfaces leading to patterns of decay that can be identified and studied. In this study, we utilized two statistical methods of extracting patterns of decay from surface-level caries data to create novel phenotypes with which to study the risk factors affecting dental caries. Intra-oral dental examinations were performed on 1068 participants aged 18-75 years to assess dental caries. The 128 tooth surfaces of the permanent dentition were scored as carious or not and used as input for principal components analysis (PCA) and factor analysis (FA), two methods of identifying underlying patterns without a priori knowledge of the patterns. Demographic (age, sex, birth year, race/ethnicity, and educational attainment), anthropometric (height, body mass index, waist circumference), endogenous (saliva flow), and environmental (tooth brushing frequency, home water source, and home water fluoride) risk factors were tested for association with the caries patterns identified by PCA and FA, as well as DMFS, for comparison. The ten strongest patterns (i.e. those that explain the most variation in the data set) extracted by PCA and FA were considered. The three strongest patterns identified by PCA reflected (i) global extent of decay (i.e. comparable to DMFS index), (ii) pit and fissure surface caries and (iii) smooth surface caries, respectively. The two strongest patterns identified by FA corresponded to (i) pit and fissure surface caries and (ii) maxillary incisor caries. Age and birth year were significantly associated with several patterns of decay, including global decay/DMFS index. Sex, race, educational attainment, and tooth brushing were each associated with specific patterns of decay, but not with global decay/DMFS index. Taken together, these results support the notion that caries experience is separable into patterns attributable to distinct risk factors. This study demonstrates the utility of such novel caries patterns as new outcomes for exploring the complex, multifactorial nature of dental caries. © 2012 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Placenta Growth Factor in Diabetic Wound Healing

PubMed Central

Cianfarani, Francesca; Zambruno, Giovanna; Brogelli, Laura; Sera, Francesco; Lacal, Pedro Miguel; Pesce, Maurizio; Capogrossi, Maurizio C.; Failla, Cristina Maria; Napolitano, Monica; Odorisio, Teresa

2006-01-01

Reduced microcirculation and diminished expression of growth factors contribute to wound healing impairment in diabetes. Placenta growth factor (PlGF), an angiogenic mediator promoting pathophysiological neovascularization, is expressed during cutaneous wound healing and improves wound closure by enhancing angiogenesis. By using streptozotocin-induced diabetic mice, we here demonstrate that PlGF induction is strongly reduced in diabetic wounds. Diabetic transgenic mice overexpressing PlGF in the skin displayed accelerated wound closure compared with diabetic wild-type littermates. Moreover, diabetic wound treatment with an adenovirus vector expressing the human PlGF gene (AdCMV.PlGF) significantly accelerated the healing process compared with wounds treated with a control vector. The analysis of treated wounds showed that PlGF gene transfer improved granulation tissue formation, maturation, and vascularization, as well as monocytes/macrophages local recruitment. Platelet-derived growth factor, fibroblast growth factor-2, and vascular endothelial growth factor mRNA levels were increased in AdCMV.PlGF-treated wounds, possibly enhancing PlGF-mediated effects. Finally, PlGF treatment stimulated cultured dermal fibroblast migration, pointing to a direct role of PlGF in accelerating granulation tissue maturation. In conclusion, our data indicate that reduced PlGF expression contributes to impaired wound healing in diabetes and that PlGF gene transfer to diabetic wounds exerts therapeutic activity by promoting different aspects of the repair process. PMID:17003476

Particle acceleration and magnetic field generation in SNR shocks

NASA Astrophysics Data System (ADS)

Suslov, M.; Diamond, P. H.; Malkov, M. A.

2006-04-01

We discuss the diffusive acceleration mechanism in SNR shocks in terms of its potential to accelerate CRs to 10^18 eV, as observations imply. One possibility, currently discussed in the literature, is to resonantly generate a turbulent magnetic field via accelerated particles in excess of the background field. We analyze some problems of this scenario and suggest a different mechanism, which is based on the generation of Alfven waves at the gyroradius scale at the background field level, with a subsequent transfer to longer scales via interaction with strong acoustic turbulence in the shock precursor. The acoustic turbulence in turn, may be generated by Drury instability or by parametric instability of the Alfven (A) waves. The essential idea is an A->A+S decay instability process, where one of the interacting scatterers (i.e. the sound, or S-waves) are driven by the Drury instability process. This rapidly generates longer wavelength Alfven waves, which in turn resonate with high energy CRs thus binding them to the shock and enabling their further acceleration.

Rare Λb→Λ l+l- and Λb→Λ γ decays in the relativistic quark model

NASA Astrophysics Data System (ADS)

Faustov, R. N.; Galkin, V. O.

2017-09-01

Rare Λb→Λ l+l- and Λb→Λ γ decays are investigated in the relativistic quark model based on the quark-diquark picture of baryons. The decay form factors are calculated accounting for all relativistic effects, including relativistic transformations of baryon wave functions from rest to a moving reference frame and the contribution of the intermediate negative-energy states. The momentum-transfer-squared dependence of the form factors is explicitly determined in the whole accessible kinematical range. The calculated decay branching fractions, various forward-backward asymmetries for the rare decay Λb→Λ μ+μ-, are found to be consistent with recent detailed measurements by the LHCb Collaboration. Predictions for the Λb→Λ τ+τ- decay observables are given.

An improved multilevel Monte Carlo method for estimating probability distribution functions in stochastic oil reservoir simulations

DOE PAGES

Lu, Dan; Zhang, Guannan; Webster, Clayton G.; ...

2016-12-30

In this paper, we develop an improved multilevel Monte Carlo (MLMC) method for estimating cumulative distribution functions (CDFs) of a quantity of interest, coming from numerical approximation of large-scale stochastic subsurface simulations. Compared with Monte Carlo (MC) methods, that require a significantly large number of high-fidelity model executions to achieve a prescribed accuracy when computing statistical expectations, MLMC methods were originally proposed to significantly reduce the computational cost with the use of multifidelity approximations. The improved performance of the MLMC methods depends strongly on the decay of the variance of the integrand as the level increases. However, the main challengemore » in estimating CDFs is that the integrand is a discontinuous indicator function whose variance decays slowly. To address this difficult task, we approximate the integrand using a smoothing function that accelerates the decay of the variance. In addition, we design a novel a posteriori optimization strategy to calibrate the smoothing function, so as to balance the computational gain and the approximation error. The combined proposed techniques are integrated into a very general and practical algorithm that can be applied to a wide range of subsurface problems for high-dimensional uncertainty quantification, such as a fine-grid oil reservoir model considered in this effort. The numerical results reveal that with the use of the calibrated smoothing function, the improved MLMC technique significantly reduces the computational complexity compared to the standard MC approach. Finally, we discuss several factors that affect the performance of the MLMC method and provide guidance for effective and efficient usage in practice.« less

Much Ado About (Almost!) Nothing: The Experimental Study of Neutrino Masses and Mixing

NASA Astrophysics Data System (ADS)

Messier, Mark

2009-11-01

Neutrinos have been described by their discoverer Frederick Reines as ``the most tiny quantity of reality ever imagined by a human being.'' Yet these particles which verge on nothingness have had an enormous influence on the past and future evolution of the universe and are the subject of an increasingly active program of experimental physics. In this talk I will review some of the basic properties of neutrinos and summarize the recent results on neutrino masses and mixing from studies of neutrinos produced in the Sun, cosmic rays, reactors, and accelerators including searches for zero neutrino double beta decay. Looking ahead, I will outline the future course of experiments in the U.S., Asia, and Europe which will address the questions of the fundamental character of the neutrino, the hierarchy of their masses, and their matter anti-matter symmetries.

Comparison Between Human and Porcine Thromboelastograph Parameters in Response to Ex-Vivo Changes to Platelets, Plasma, and Red Blood Cells

DTIC Science & Technology

2013-01-01

diluted with lactated Ringer’s solution. We demonstrated that the major factor affecting the MA and angle was the platelet count. In fact, reducing...with an accelerant, either kaolin or tissue factor or both as in the case of ‘rapid’ TEG. The TEG tracing represents the cell-based theory of...There are claims in the trauma literature that the pro- longation of the R-time reflects clotting factor deficiency or dilution, prolongation of K

Collective acceleration of ions in picosecond pinched electron beams

NASA Astrophysics Data System (ADS)

Baryshnikov, V. I.; Paperny, V. L.; Shipayev, I. V.

2017-10-01

Сharacteristics of intense electron-ion beams emitted by a high-voltage (280 kV) electron accelerator with a pulse duration of 200 ps and current 5 kA are studied. The capture phenomena and the subsequent collective acceleration of multi charged ions of the cathode material by the electric field of the electron beam are observed. It is shown that the electron-ion beam diameter does not exceed 30 µm therein in the case of lighter ions, and the decay of the pinched beam occurs at a shorter distance from the cathode. It is established that the ions of the cathode material Tin+ captured by the electron beam are accelerated up to an energy of  ⩽10 MeV, and the ion fluence reaches 1017 ion cm-2 in the pulse. These ions are effectively embedded into the lattice sites of the irradiated substrate (sapphire crystal), forming the luminescent areas of the micron scale.

The decay of wood in landfills in contrasting climates in Australia

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ximenes, Fabiano, E-mail: fabiano.ximenes@dpi.nsw.gov.au; Björdal, Charlotte; Cowie, Annette

Highlights: • We examine decay in wood from landfills in contrasting environments in Australia. • Analysis is based on changes in chemical composition and microscopy. • Climate did not influence levels of decay observed. • Microscopy of retrieved samples revealed most of the decay was aerobic in nature. • Current default factors for wood decay in landfills overestimate methane emissions. - Abstract: Wood products in landfill are commonly assumed to decay within several decades, returning the carbon contained therein to the atmosphere, with about half the carbon released as methane. However, the rate and extent of decay is not wellmore » known, as very few studies have examined the decay of wood products in landfills. This study reports on the findings from landfill excavations conducted in the Australian cities of Sydney and Cairns located in temperate and tropical environments, respectively. The objective of this study was to determine whether burial of the wood in warmer, more tropical conditions in Cairns would result in greater levels of decay than occurs in the temperate environment of Sydney. Wood samples recovered after 16–44 years in landfill were examined through physical, chemical and microscopic analyses, and compared with control samples to determine the carbon loss. There was typically little or no decay in the wood samples analysed from the landfill in Sydney. Although there was significant decay in rainforest wood species excavated from Cairns, decay levels for wood types that were common to both Cairns and Sydney landfills were similar. The current Intergovernmental Panel on Climate Change (IPCC, 2006) default decay factor for organic materials in landfills is 50%. In contrast, the carbon loss determined for Pinus radiata recovered from Sydney and Cairns landfills was 7.9% and 4.4%, respectively, and 0% for Agathis sp. This suggests that climate did not influence decay, and that the more extensive levels of decay observed for some wood samples from Cairns indicates that those wood types were more susceptible to biodegradation. Microscopic analyses revealed that most decay patterns observed in samples analysed from Sydney were consistent with aerobic fungal decay. Only a minor portion of the microbial decay was due to erosion bacteria active in anaerobic/near anaerobic environments. The findings of this study strongly suggest that models that adopt current accepted default factors for the decay of wood in landfills greatly overestimate methane emissions.« less

Distribution of N2O in the atmosphere under global warming - a simulation study with the MPI Earth System Model

NASA Astrophysics Data System (ADS)

Kracher, Daniela; Manzini, Elisa; Reick, Christian H.; Schultz, Martin; Stein, Olaf

2014-05-01

Climate change is driven by an increasing release of anthropogenic greenhouse gases (GHGs) such as carbon dioxide and nitrous oxide (N2O). Besides fossil fuel burning, also land use change and land management are anthropogenic sources of GHGs. Especially inputs of reactive nitrogen via fertilizer and deposition lead to enhanced emissions of N2O. One effect of a drastic future increase in surface temperature is a modification of atmospheric circulation, e.g. an accelerated Brewer Dobson circulation affecting the exchange between troposphere and stratosphere. N2O is inert in the troposphere and decayed only in the stratosphere. Thus, changes in atmospheric circulation, especially changes in the exchange between troposphere and stratosphere, will affect the atmospheric transport, decay, and distribution of N2O. In our study we assess the impact of global warming on atmospheric circulation and implied effects on the distribution and lifetime of atmospheric N2O. As terrestrial N2O emissions are highly determined by inputs of reactive nitrogen - the location of which being determined by human choice - we examine in particular the importance of latitudinal source regions of N2O for its global distribution. For this purpose we apply the Max Planck Institute Earth System Model, MPI-ESM. MPI-ESM consists of the atmospheric general circulation model ECHAM, the land surface model JSBACH, and MPIOM/HAMOCC representing ocean circulation and ocean biogeochemistry. Prognostic atmospheric N2O concentrations in MPI-ESM are determined by land N2O emissions, ocean N2O exchange and atmospheric tracer transport. As stratospheric chemistry is not explicitly represented in MPI-ESM, stratospheric decay rates of N2O are prescribed from a MACC MOZART simulation.

Comparative genome analysis of Streptococcus infantarius subsp. infantarius CJ18, an African fermented camel milk isolate with adaptations to dairy environment.

PubMed

Jans, Christoph; Follador, Rainer; Hochstrasser, Mira; Lacroix, Christophe; Meile, Leo; Stevens, Marc J A

2013-03-22

Streptococcus infantarius subsp. infantarius (Sii) belongs to the Streptococcus bovis/Streptococcus equinus complex associated with several human and animal infections. Sii is a predominant bacterium in spontaneously fermented milk products in Africa. The genome sequence of Sii strain CJ18 was compared with that of other Streptococcus species to identify dairy adaptations including genome decay such as in Streptococcus thermophilus, traits for its competitiveness in spontaneous milk fermentation and to assess potential health risks for consumers. The genome of Sii CJ18 harbors several unique regions in comparison to Sii ATCC BAA-102T, among others an enlarged exo- and capsular polysaccharide operon; Streptococcus thermophilus-associated genes; a region containing metabolic and hypothetical genes mostly unique to CJ18 and the dairy isolate Streptococcus gallolyticus subsp. macedonicus; and a second oligopeptide transport operon. Dairy adaptations in CJ18 are reflected by a high percentage of pseudogenes (4.9%) representing genome decay which includes the inactivation of the lactose phosphotransferase system (lacIIABC) by multiple transposases integration. The presence of lacS and lacZ genes is the major dairy adaptation affecting lactose metabolism pathways also due to the disruption of lacIIABC.We constructed mutant strains of lacS, lacZ and lacIIABC and analyzed the resulting strains of CJ18 to confirm the redirection of lactose metabolism via LacS and LacZ.Natural competence genes are conserved in both Sii strains, but CJ18 contains a lower number of CRISPR spacers which indicates a reduced defense capability against alien DNA. No classical streptococcal virulence factors were detected in both Sii strains apart from those involved in adhesion which should be considered niche factors. Sii-specific virulence factors are not described. Several Sii-specific regions encoding uncharacterized proteins provide new leads for virulence analyses and investigation of the unclear association of dairy and clinical Sii with human diseases. The genome of the African dairy isolate Sii CJ18 clearly differs from the human isolate ATCC BAA-102T. CJ18 possesses a high natural competence predisposition likely explaining the enlarged genome. Metabolic adaptations to the dairy environment are evident and especially lactose uptake corresponds to S. thermophilus. Genome decay is not as advanced as in S. thermophilus (10-19%) possibly due to a shorter history in dairy fermentations.

Comparative genome analysis of Streptococcus infantarius subsp. infantarius CJ18, an African fermented camel milk isolate with adaptations to dairy environment

PubMed Central

2013-01-01

Background Streptococcus infantarius subsp. infantarius (Sii) belongs to the Streptococcus bovis/Streptococcus equinus complex associated with several human and animal infections. Sii is a predominant bacterium in spontaneously fermented milk products in Africa. The genome sequence of Sii strain CJ18 was compared with that of other Streptococcus species to identify dairy adaptations including genome decay such as in Streptococcus thermophilus, traits for its competitiveness in spontaneous milk fermentation and to assess potential health risks for consumers. Results The genome of Sii CJ18 harbors several unique regions in comparison to Sii ATCC BAA-102T, among others an enlarged exo- and capsular polysaccharide operon; Streptococcus thermophilus-associated genes; a region containing metabolic and hypothetical genes mostly unique to CJ18 and the dairy isolate Streptococcus gallolyticus subsp. macedonicus; and a second oligopeptide transport operon. Dairy adaptations in CJ18 are reflected by a high percentage of pseudogenes (4.9%) representing genome decay which includes the inactivation of the lactose phosphotransferase system (lacIIABC) by multiple transposases integration. The presence of lacS and lacZ genes is the major dairy adaptation affecting lactose metabolism pathways also due to the disruption of lacIIABC. We constructed mutant strains of lacS, lacZ and lacIIABC and analyzed the resulting strains of CJ18 to confirm the redirection of lactose metabolism via LacS and LacZ. Natural competence genes are conserved in both Sii strains, but CJ18 contains a lower number of CRISPR spacers which indicates a reduced defense capability against alien DNA. No classical streptococcal virulence factors were detected in both Sii strains apart from those involved in adhesion which should be considered niche factors. Sii-specific virulence factors are not described. Several Sii-specific regions encoding uncharacterized proteins provide new leads for virulence analyses and investigation of the unclear association of dairy and clinical Sii with human diseases. Conclusions The genome of the African dairy isolate Sii CJ18 clearly differs from the human isolate ATCC BAA-102T. CJ18 possesses a high natural competence predisposition likely explaining the enlarged genome. Metabolic adaptations to the dairy environment are evident and especially lactose uptake corresponds to S. thermophilus. Genome decay is not as advanced as in S. thermophilus (10-19%) possibly due to a shorter history in dairy fermentations. PMID:23521820

High-resolution γ-ray spectroscopy: a versatile tool for nuclear β-decay studies at TRIUMF-ISAC

NASA Astrophysics Data System (ADS)

Ball, G. C.; Achtzehn, T.; Albers, D.; Khalili, J. S. Al; Andreoiu, C.; Andreyev, A.; Ashley, S. F.; Austin, R. A. E.; Becker, J. A.; Bricault, P.; Chan, S.; Chakrawarthy, R. S.; Churchman, R.; Coombes, H.; Cunningham, E. S.; Daoud, J.; Dombsky, M.; Drake, T. E.; Eshpeter, B.; Finlay, P.; Garrett, P. E.; Geppert, C.; Grinyer, G. F.; Hackman, G.; Hanemaayer, V.; Hyland, B.; Jones, G. A.; Koopmans, K. A.; Kulp, W. D.; Lassen, J.; Lavoie, J. P.; Leslie, J. R.; Litvinov, Y.; Macdonald, J. A.; Mattoon, C.; Melconian, D.; Morton, A. C.; Osborne, C. J.; Pearson, C. J.; Pearson, M.; Phillips, A. A.; Ressler, J. J.; Sarazin, F.; Schumaker, M. A.; Schwarzenberg, J.; Scraggs, H. C.; Smith, M. B.; Svensson, C. E.; Valiente-Dobon, J. J.; Waddington, J. C.; Walker, P. M.; Wendt, K.; Williams, S. J.; Wood, J. L.; Zganjar, E. F.

2005-10-01

High-resolution γ-ray spectroscopy is essential to fully exploit the unique, high-quality beams available at the next generation of radioactive ion beam facilities such as the TRIUMF isotope separator and accelerator (ISAC). The 8π spectrometer, which consists of 20 Compton-suppressed HPGe detectors, has recently been reconfigured for a vigorous research programme in weak interaction and nuclear structure physics. With the addition of a variety of ancillary detectors it has become the world's most powerful device dedicated to β-decay studies. This paper provides a brief overview of the apparatus and highlights from recent experiments.

Co-doping effects on luminescence and scintillation properties of Ce doped (Lu,Gd)3(Ga,Al)5O12 scintillator

NASA Astrophysics Data System (ADS)

Yamaguchi, Hiroaki; Kamada, Kei; Kurosawa, Shunsuke; Pejchal, Jan; Shoji, Yasuhiro; Yokota, Yuui; Ohashi, Yuji; Yoshikawa, Akira

2016-11-01

Mg co-doping effects on scintillation properties of Ce:Lu1Gd2(Ga,Al)5O12 (LGGAG) were investigated. Mg 200 ppm co-doped Ce:LGGAG single crystals were prepared by micro pulling down method. Absorption and luminescence spectra were measured together with several other scintillation characteristics, namely the scintillation decay and light yield to reveal the effect of Mg co-doping. Ce4+ charge transfer absorption was observed below 300 nm in Mg,Ce:LGGAG which is in good agreement with previous reports. The scintillation decay times were accelerated by Mg co-doping.

The impact of the postharvest environment on the viability and virulence of decay fungi

USDA-ARS?s Scientific Manuscript database

Postharvest decay of fruits, vegetables, and grains by fungal pathogens causes significant economic losses. Infected produce presents a potential health risk since some decay fungi produce mycotoxins that are hazardous to human health. Infections are the result of the interplay between host resist...

Probing SEP Acceleration Processes With Near-relativistic Electrons

NASA Astrophysics Data System (ADS)

Haggerty, Dennis K.; Roelof, Edmond C.

2009-11-01

Processes in the solar corona are prodigious accelerators of near-relativistic electrons. Only a small fraction of these electrons escape the low corona, yet they are by far the most abundant species observed in Solar Energetic Particle events. These beam-like energetic electron events are sometimes time-associated with coronal mass ejections from the western solar hemisphere. However, a significant number of events are observed without any apparent association with a transient event. The relationship between solar energetic particle events, coronal mass ejections, and near-relativistic electron events are better ordered when we classify the intensity time profiles during the duration of the beam-like anisotropies into three broad categories: 1) Spikes (rapid and equal rise and decay) 2) Pulses (rapid rise, slower decay) and 3) Ramps (rapid rise followed by a plateau). We report on the results of a study that is based on our catalog (covering nearly the complete Solar Cycle 23) of 216 near-relativistic electron events and their association with: solar electromagnetic emissions, shocks driven by coronal mass ejections, models of the coronal magnetic fields and energetic protons. We conclude that electron events with time-intensity profiles of Spikes and Pulses are associated with explosive events in the low corona while events with time-intensity profiles of Ramps are associated with the injection/acceleration process of the CME driven shock.

The logarithmic and power law behaviors of the accelerating, turbulent thermal boundary layer

NASA Astrophysics Data System (ADS)

Castillo, Luciano; Hussain, Fazle

2017-02-01

Direct numerical simulation of spatially evolving thermal turbulent boundary layers with strong favorable pressure gradient (FPG) shows that the thermal fluctuation intensity, θ' + and the Reynolds shear stress, u'v'¯+ exhibit a logarithmic behavior spanning the meso-layer (e.g., 50 ≤y+≤170 ). However, the mean thermal profile is not logarithmic even in the zero pressure gradient (ZPG) region; instead, it follows a power law. The maxima of u' 2 ¯+ and v'θ'¯+ change little with the strength of acceleration, while v'+, w'+, and u'v'¯+ continue to decay in the flow direction. Furthermore, θ'+ and u'θ'¯+ surprisingly experience changes from constants in ZPG to sharp rises in the FPG region. Such behavior appears to be due to squashing of the streaks which decreases the streak flank angle below the critical value for "transient growth" generation of streamwise vortices, shutting down production [W. Schoppa and F. Hussain, "Coherent structure generation near-wall turbulence," J. Fluid Mech. 453, 57-108 (2002)]. The streamwise vortices near the wall, although shrink because of stretching, simultaneously, also become weaker as the structures are progressively pushed farther down to the more viscous region near the wall. While the vortical structures decay rapidly in accelerating flows, the thermal field does not—nullifying the myth that both the thermal and velocity fields are similar.

Radiation Protection. Measurement of radioactivity in the environment - Air- radon 222. A proposed ISO standard.

NASA Astrophysics Data System (ADS)

Gillmore, G.; Woods, M.

2009-04-01

Radon isotopes (222, 220, 219) are radioactive gases produced by the disintegration of radium isotopes 226, 224 and 223, which are decay products of uranium238, thorium232 and uranium235 respectively. All are found in the earth's crust. Solid elements, also radioactive, are produced by radon disintegration. Radon is classed as a rare gas in the periodic table of elements, along with helium, argon, neon, krypton and xenon. When disintegrating, radon emits alpha particles and generates solid decay products, which are also radioactive (polonium, bismuth, lead etc.). The potential danger of radon lies in its solid decay products rather than the gas itself. Whether or not they are attached aerosols, radon decay products can be inhaled and deposited in the bronchopulmonary tree to varying depths according to their size. Radon today is considered to be the main source of human exposure to natural radiation. At the international level, radon accounts for 52% of global average exposure to natural radiation. Isotope 222 (48%) is far more significant than isotope 220 (4%), whilst isotope 219 is considered as negligible. Exposure to radon varies considerably from one region to another, depending on factors such as weather conditions, and underlying geology. Activity concentration can therefore vary by a factor of 10 or even a 100 from one period of time to the next and from one area to another. There are many ways of measuring the radon 222 activity concentration and the potential alpha energy concentration of its short-lived decay products. Measuring techniques fall into three categories: - spot measurement methods; continuous measurement; integrated measurement. The proposed ISO (International Organisation for Standardisation) document suggests guidelines for measuring radon222 activity concentration and the potential alpha energy concentration of its short-lived decay products in a free (environment) and confined (buildings) atmosphere. The target date for availability of this work item is 2011. The ISO document here highlighted is a working draft. ISO is a worldwide federation of national standards bodies. Keywords: radon; international standards; measurement techniques.

Beam trapping in high-current cyclic accelerators with strong-focusing fields. Memorandum report, January-December 1984

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sprangle, P.; Kapetanakos, C.A.

1985-03-06

In cyclic induction accelerators, the energy of the particles increases slowly in synchronism with the vertical (betatron) magnetic field. As a consequence of the slow acceleration, the charged particles must be confined by the weak-focusing magnetic field over long periods of time, and thus field errors, instabilities, and radiation losses can impose limitations on the acceleration process. These limitations can be substantially relaxed if the acceleration were to occur rapidly, say over a few microseconds. An appropriate name for such an accelerator is REBA-TRON (Rapid Electron Beam Accelerator). This paper considers a possible mechanism which could trap a high currentmore » electron beam in the strong focusing magnetic fields of the rebatron. We investigate a possible mechanism for trapping an intense relativistic electron beam confined by strong focusing fields. In our model the electron beam is assumed to be injected into torsatron fields off axis, near the chamber walls. The finite resistivity of the walls results in a drag force on the beam centroid which may cause the beam to spiral inward towards the axis of the chamber. We have analyzed this mechanism and obtained decay rates for the inward spiraling beam motion.« less

Interaction of recombinant human epidermal growth factor with phospholipid vesicles. A steady-state and time-resolved fluorescence study of the bis-tryptophan sequence (Trp49-Trp50).

PubMed

Li De La Sierra, I M; Vincent, M; Padron, G; Gallay, J

1992-01-01

The interaction of recombinant human epidermal growth factor with small unilamellar phospholipid vesicles was studied by steady-state and time-resolved fluorescence of the bis-tryptophan sequence (Trp49-Trp50). Steady-state anisotropy measurements demonstrate that strong binding occurred with small unilamellar vesicles made up of acidic phospholipids at acidic pH only (pH < or = 4.7). An apparent stoichiometry for 1,2-dimyristoyl-sn-phosphoglycerol of about 12 phospholipid molecules per molecule of human epidermal growth factor was estimated. The binding appears to be more efficient at temperatures above the gel to liquid-crystalline phase transition. The conformation and the environment of the Trp-Trp sequence are not greatly modified after binding, as judged from the invariance of the excited state lifetime distribution and from that of the fast processes affecting the anisotropy decay. This suggests that the Trp-Trp sequence is not embedded within the bilayer, in contrast to the situation in surfactant micelles (Mayo et al. 1987; Kohda and Inigaki 1992).

Gamma-Ray Spectroscopy at TRIUMF-ISAC: the New Frontier of Radioactive Ion Beam Research

NASA Astrophysics Data System (ADS)

Ball, G. C.; Andreoiu, C.; Austin, R. A. E.; Bandyopadhyay, D.; Becker, J. A.; Bricault, P.; Brown, N.; Chan, S.; Churchman, R.; Colosimo, S.; Coombes, H.; Cross, D.; Demand, G.; Drake, T. E.; Dombsky, M.; Ettenauer, S.; Finlay, P.; Furse, D.; Garnsworthy, A.; Garrett, P. E.; Green, K. L.; Grinyer, G. F.; Hyland, B.; Hackman, G.; Kanungo, R.; Kulp, W. D.; Lassen, J.; Leach, K. G.; Leslie, J. R.; Mattoon, C.; Melconian, D.; Morton, A. C.; Pearson, C. J.; Phillips, A. A.; Rand, E.; Sarazin, F.; Svensson, C. E.; Sumithrarachchi, S.; Schumaker, M. A.; Triambak, S.; Waddington, J. C.; Walker, P. M.; Williams, S. J.; Wood, J. L.; Wong, J.; Zganjar, E. F.

2009-03-01

High-resolution gamma-ray spectroscopy is essential to fully exploit the unique scientific opportunities at the next generation radioactive ion beam facilities such as the TRIUMF Isotope Separator and Accelerator (ISAC). At ISAC the 8π spectrometer and its associated auxiliary detectors is optimize for β-decay studies while TIGRESS an array of segmented clover HPGe detectors has been designed for studies with accelerated beams. This paper gives a brief overview of these facilities and also presents recent examples of the diverse experimental program carried out at the 8π spectrometer.

Observations of radiation damage and recovery in ammonia targets

NASA Astrophysics Data System (ADS)

McKee, P. M.

2004-06-01

The Polarized Target Group at the University of Virginia has conducted experiments at both the Stanford Linear Accelerator Center (SLAC) and the Thomas Jefferson National Accelerator Facility (JLab) in which a high-intensity (100 nA) electron beam was focused on a polarized target of solid ammonia and/ or solid, deuterated ammonia. Analysis of the target polarization data have revealed several unique characteristics of ammonia. Topics discussed include the rate of polarization decay with accumulated charge, methods of recovering polarization through target annealing and damage-induced shifts in the optimum microwave frequency used to drive the polarization.

Optimization of radiation shielding material aiming at compactness, lightweight, and low activation for a vehicle-mounted accelerator-driven D-T neutron source.

PubMed

Cai, Yao; Hu, Huasi; Lu, Shuangying; Jia, Qinggang

2018-05-01

To minimize the size and weight of a vehicle-mounted accelerator-driven D-T neutron source and protect workers from unnecessary irradiation after the equipment shutdown, a method to optimize radiation shielding material aiming at compactness, lightweight, and low activation for the fast neutrons was developed. The method employed genetic algorithm, combining MCNP and ORIGEN codes. A series of composite shielding material samples were obtained by the method step by step. The volume and weight needed to build a shield (assumed as a coaxial tapered cylinder) were adopted to compare the performance of the materials visually and conveniently. The results showed that the optimized materials have excellent performance in comparison with the conventional materials. The "MCNP6-ACT" method and the "rigorous two steps" (R2S) method were used to verify the activation grade of the shield irradiated by D-T neutrons. The types of radionuclide, the energy spectrum of corresponding decay gamma source, and the variation in decay gamma dose rate were also computed. Copyright © 2018 Elsevier Ltd. All rights reserved.

Issues in Acceleration of A Muon Beam for a Neutrino Factory

DOE Office of Scientific and Technical Information (OSTI.GOV)

J. Delayen; D. Douglas; L. Harwood

2001-06-01

We have developed a concept for acceleration of a large phase-space, pulsed muon beam from 190 MeV to 50 GeV as part of a collaborative study of the feasibility of a neutrino factory based on in-flight decay of muons. The muon beam's initial energy spread was {approximately}20% and each bunch has the physical size of a soccer ball. Production of the muons will be quite expensive, so prevention of loss due to scraping or decay is critical. The former drives the system to large apertures and the latter calls for high real-estate-average gradients. The solution to be presented utilizes amore » 3 GeV linac to capture the beam, a 4-pass recirculating linac to get the beam to 10 GeV, and then a 5-pass linac to get the beam to 50 GeV. Throughout the system, longitudinal dynamics issues far outweighed transverse dynamics issues. This paper focuses on the issues surrounding the choice of superconducting rf structures over copper structures.« less

Research in Lattice Gauge Theory and in the Phenomenology of Neutrinos and Dark Matter

DOE Office of Scientific and Technical Information (OSTI.GOV)

Meurice, Yannick L; Reno, Mary Hall

Research in theoretical elementary particle physics was performed by the PI Yannick Meurice and co-PI Mary Hall Reno. New techniques designed for precision calculations of strong interaction physics were developed using the tensor renormalization group method. Large-scale Monte Carlo simulations with dynamical quarks were performed for candidate models for Higgs compositeness. Ab-initio lattice gauge theory calculations of semileptonic decays of B-mesons observed in collider experiments and relevant to test the validity of the standard model were performed with the Fermilab/MILC collaboration. The phenomenology of strong interaction physics was applied to new predictions for physics processes in accelerator physics experiments andmore » to cosmic ray production and interactions. A research focus has been on heavy quark production and their decays to neutrinos. The heavy quark contributions to atmospheric neutrino and muon fluxes have been evaluated, as have the neutrino fluxes from accelerator beams incident on heavy targets. Results are applicable to current and future particle physics experiments and to astrophysical neutrino detectors such as the IceCube Neutrino Observatory.« less

Neurotrophin-3 accelerates wound healing in diabetic mice by promoting a paracrine response in mesenchymal stem cells.

PubMed

Shen, Lei; Zeng, Wen; Wu, Yang-Xiao; Hou, Chun-Li; Chen, Wen; Yang, Ming-Can; Li, Li; Zhang, Ya-Fang; Zhu, Chu-Hong

2013-01-01

Angiogenesis is a major obstacle for wound healing in patients with diabetic foot wounds. Mesenchymal stem cells (MSCs) have an important function in wound repair, and neurotrophin-3 (NT-3) can promote nerve regeneration and angiogenesis. We investigated the effect of NT-3 on accelerating wound healing in the diabetic foot by improving human bone marrow MSC (hMSC) activation. In vitro, NT-3 significantly promoted VEGF, NGF, and BDNF secretion in hMSCs. NT-3 improved activation of the hMSC conditioned medium, promoted human umbilical vein endothelial cell (HUVEC) proliferation and migration, and significantly improved the closure rate of HUVEC scratches. In addition, we produced nanofiber mesh biological tissue materials through the electrospinning technique using polylactic acid, mixed silk, and collagen. The hMSCs stimulated by NT-3 were implanted into the material. Compared with the control group, the NT-3-stimulated hMSCs in the biological tissue material significantly promoted angiogenesis in the feet of diabetic C57BL/6J mice and accelerated diabetic foot wound healing. These results suggest that NT-3 significantly promotes hMSC secretion of VEGF, NGF, and other vasoactive factors and that it accelerates wound healing by inducing angiogenesis through improved activation of vascular endothelial cells. The hMSCs stimulated by NT-3 can produce materials that accelerate wound healing in the diabetic foot and other ischemic ulcers.

High Energy Phenomenology - Proceedings of the Workshop

NASA Astrophysics Data System (ADS)

Pérez, Miguel A.; Huerta, Rodrigo

1992-06-01

The Table of Contents for the full book PDF is as follows: * Preface * Radiative Corrections in the Electroweak Standard Model * Introduction * The Electroweak Standard Model and its Renormalization * Basic Properties of the Standard Model * Renormalization of the Standard Model * Calculation of Radiative Corrections * One-Loop Integrals * Corrected Matrix Elements and Cross Sections * Photonic Corrections * Physical Applications and Results * Parameter Relations in Higher Orders * Decay Widths * Z Physics * W-Pair Production * Higgs Production in e+e- Annihilation * Conclusion * Appendix: Feynman Rules * References * Hadron Collider Physics * Introduction * e+ e- Annihilation * The Standard Model * The Drell-Yan Process in Hadronic Collisions * The Structure Functions * Hadronic Z Production * Hadronic W Production * The Transverse Mass * Quark Decays of W's * Weak Interactions * Neutrino Scattering * Weak Neutral Currents * The Standard Model * Symmetries and Lagrangians * Spontaneous Symmetry Breaking * The Standard Model Again * Experimental Situation * Appendix * References * Lectures on Heavy Quark Effective Theory * Introduction * Motivation * Physical Intuition * The Heavy Quark Effective Theory * The Effective Lagrangian and its Feynman Rules * What is an Effective Theory? * The Effective Theory Beyond Tree Level * External Currents * Leading-Logs or No Leading-Logs; A digression * Sample Calculations * Symmetries * Flavor-SU(N) * Spin-SU(2) * Spectrum * Strong Transitions * Covariant Representation of States * Meson Decay Constants * Preliminaries * Formal Derivation: Green Functions * Quick and Dirty Derivation: States in the HQET * Vector Meson Decay Constant * Corrections * Form Factors in overline {B} rightarrow Deν and overline {B} rightarrow D ^ast {e}ν * Preliminaries * Form Factors in the HQET * Form Factors in order αs * 1/MQ * The Correcting Lagrangian * The Corrected Currents * Corrections of order mc/mb * Corrections of order overline {Λ} /m_c and overline {Λ} /m_c * Conclusions and More * Inclusive Semileptonic Decay Rates * overline {B} rightarrow Π {e} overline {ν} and overline {B} rightarrow Π {e} overline {ν} * Rare overline {B} decays * e^+ e^- rightarrow {B} overline {B} * λb → λcDs vs λb → λc D*s * Factorization * A Last Word (or Two) * References * An Overview of Nonleptonic Decays of B, D, K Mesons and CP-Noninvariance * Generic Ways to Study Nonleptonic Decays and CP-Noninvariance * The Quark-Diagram Scheme * Invariants of the CKM and the Universal Decay-Amplitude CP-Noninvariance Factor Xcp * Implications of Measuring Partial-Decay-Rate Asymmetries in B± Decays and in Neutral B Decays such as B0, overline {B}^{0} rightarrow K_sJ/{Ψ} * Nonleptonic Decays of D Mesons: From the CKM Non- and Singly-Suppressed Decays to the Predictions of Doubly-Suppressed Decays * Charm Meson D Decays into Vector and Pseudoscalar Bosons, D → VP * Charm Meson Decays into Pseudoscalar-Pseudoscalar Mesons, D → PP * Charm Meson Decays into Vector-Vector Mesons, D → VV * Nonleptonic Decays of B Mesons * The CKM Non-Suppressed Decays * Interesting Features in the Rare B Meson Decays * CP-Noninvariance in K Meson Decays * Implications of Measurement of Re( ɛ'/ɛ) * Other Important Searches for Decay-Amplitude CP Noninvariance in Strange Particles * Some Generic Properties of Decay-Amplitude CP-Noninvariance * References * Top Quark Physics * Introduction * The Top Quark Exists * Upper Limit on Mt * Other Constraints on Mt * Production of Top * Hadron Colliders * SM Top Decays * Detecting SM Tops-Signatures * Model-Independent Lower Limit on Mt * Determining the Charge of a New Heavy Quark * When the Top Quark is Detected * Top Decays - A Window to New Physics? * - Decay to Supersymmetric Partners * - Decay to Charged Higgs Bosons * - Flavor-Changing Neutral Current Decays * - Other possibilities * New Information Once Top is Observed * Studying the Top Decays Couplings * The Top Quark at N LC * Measuring Mt - How Well? * Sharper Predictions for Many Observables * Measuring Vts, Vtd, Vtb and Γ(t → bW) * Top Polarization Predictions - A New Observable * Testing QCD Polarization Predictions * Correlation of Top Spin Direction with Final b, l+ Directions and Top Mass Measurements * Measuring P_{pm} ^ t * General Top Couplings * One Loop Corrections to Top Decay * Decay Helicity Amplitudes * New Sources of CP Violation at the Weak Scale? * The Effect of Top Loops on Higgs Masses * Is t → Wb a Background for Studying TeV WW Interactions? * Predictions for Mt * Final Remarks * References * High Precision Radiative Corrections in the Semileptonic Decays of Hyperons * On the Decay W± → P±γ * The Decay H0 → γγ and Physics Beyond the Standard Model * Neutrino Masses and Double Beta Decay * Neutrino Oscillations in a Medium: Analytic Calculation of Nonadiabatic Transitions * Gauge-Invariant Perturbation Theory Near a Gauge Resonance * Lower Dimensional Divergences in Gauge Theories * Strange Stars: Which is the Ground State of QCD at Finite Baryon Number? * Experimental Signatures of the SU(5)c Color Model * Generalized Supersymmetric Quantum Mechanics * Chern-Simons Theories in 2 + 1 Dimensions * List of participants

Neutrino Mass Bounds from 0{nu}{beta}{beta} Decays and Large Scale Structures

DOE Office of Scientific and Technical Information (OSTI.GOV)

Keum, Y.-Y.; Department of Physics, National Taiwan University, Taipei, Taiwan 10672; Ichiki, K.

2008-05-21

We investigate the way how the total mass sum of neutrinos can be constrained from the neutrinoless double beta decay and cosmological probes with cosmic microwave background (WMAP 3-year results), large scale structures including 2dFGRS and SDSS data sets. First we discuss, in brief, on the current status of neutrino mass bounds from neutrino beta decays and cosmic constrain within the flat {lambda}CMD model. In addition, we explore the interacting neutrino dark-energy model, where the evolution of neutrino masses is determined by quintessence scalar filed, which is responsable for cosmic acceleration today. Assuming the flatness of the universe, the constraintmore » we can derive from the current observation is {sigma}m{sub {nu}}<0.87 eV at the 95% confidence level, which is consistent with {sigma}m{sub {nu}}<0.68 eV in the flat {lambda}CDM model.« less

Effect of solenoidal magnetic field on drifting laser plasma

NASA Astrophysics Data System (ADS)

Takahashi, Kazumasa; Okamura, Masahiro; Sekine, Megumi; Cushing, Eric; Jandovitz, Peter

2013-04-01

An ion source for accelerators requires to provide a stable waveform with a certain pulse length appropriate to the application. The pulse length of laser ion source is easy to control because it is expected to be proportional to plasma drifting distance. However, current density decay is proportional to the cube of the drifting distance, so large current loss will occur under unconfined drift. We investigated the stability and current decay of a Nd:YAG laser generated copper plasma confined by a solenoidal field using a Faraday cup to measure the current waveform. It was found that the plasma was unstable at certain magnetic field strengths, so a baffle was introduced to limit the plasma diameter at injection and improve the stability. Magnetic field, solenoid length, and plasma diameter were varied in order to find the conditions that minimize current decay and maximize stability.

Eliminating Voltage Decay of Lithium-Rich Li 1.14Mn 0.54Ni 0.14Co 0.14O 2 Cathodes by Controlling the Electrochemical Process

DOE PAGES

Wei, Z.; Zhu, Y.; Zhang, W.; ...

2015-03-27

Lithium-rich material owns a particularly high capacity owing to the activation of electrochemical inactive Li 2MnO 3 phase. But at the same time, MnO 2 phase formed after Li 2MnO 3 activation confronts a severe problem of converting to spinel phase, and resulting in voltage decay. To our knowledge, this phenomenon is inherent property of layered manganese oxide materials and can hardly be overcome. Based on this, unlike previous reports, herein we design a method for the first time to accelerate the phase transformation by tuning the charge upper-limit voltage at a high value, so the phase transformation process canmore » be finished in a few cycles. Then material structure remains stable while cycling at a low upper-limit voltage. By this novel method voltage decay is eliminated significantly.« less

Spanwise Spacing Effects on the Initial Structure and Decay of Axial Vortices

NASA Technical Reports Server (NTRS)

Wendt, B. J.; Reichert, B. A.

1996-01-01

The initial structure and axial decay of an array of streamwise vortices embedded in a turbulent pipe boundary layer is experimentally investigated. The vortices are shed in counter-rotating fashion from an array of equally-spaced symmetric airfoil vortex generators. Vortex structure is quantified in terms of crossplane circulation and peak streamwise vorticity. Flow conditions are subsonic and incompressible. The focus of this study is on the effect of the initial spacing between the parent vortex generators. Arrays with vortex generators spaced at 15 and 30 degrees apart are considered. When the spacing between vortex generators is decreased the circulation and peak vorticity of the shed vortices increases. Analysis indicates this strengthening results from regions of fluid acceleration in the vicinity of the vortex generator array. Decreased spacing between the constituent vortices also produces increased rates of circulation and peak vorticity decay.

Ground-motion prediction from tremor

USGS Publications Warehouse

Baltay, Annemarie S.; Beroza, Gregory C.

2013-01-01

The widespread occurrence of tremor, coupled with its frequency content and location, provides an exceptional opportunity to test and improve strong ground-motion attenuation relations for subduction zones. We characterize the amplitude of thousands of individual 5 min tremor events in Cascadia during three episodic tremor and slip events to constrain the distance decay of peak ground acceleration (PGA) and peak ground velocity (PGV). We determine the anelastic attenuation parameter for ground-motion prediction equations (GMPEs) to a distance of 150 km, which is sufficient to place important constraints on ground-motion decay. Tremor PGA and PGV show a distance decay that is similar to subduction-zone-specific GMPEs developed from both data and simulations; however, the massive amount of data present in the tremor observations should allow us to refine distance-amplitude attenuation relationships for use in hazard maps, and to search for regional variations and intrasubduction zone differences in ground-motion attenuation.

Effects of Biosynthetic Human Epidermal Growth Factor on Wound Healing

DTIC Science & Technology

1986-10-27

regenerated or been replaced with autograft skin. The limiting factor in covering major third degree burns is the availability of autogenous skin grafts . Although...tho patient’s own skin. Since the only permant solution currently available is autografting, an agent that would accelerate healing of skin graft donor...biodegradation. Additional valuable information will be obtained when the limited clinical trial using EGF in Silvadene to treat skin graft donor sites begins

Growth factors, nutrient signaling, and cardiovascular aging

PubMed Central

Fontana, Luigi; Vinciguerra, Manlio; Longo, Valter D.

2012-01-01

Growth factors regulated by specific macronutrients have been shown to promote aging and accelerate mortality in the great majority of the organisms studied. In particular, the enzymes activated by growth hormone (GH), insulin and insulin-like growth factor 1 (IGF-I) in mammals and their orthologs in simple model organisms represent perhaps the best-understood proteins involved in the aging process. Dietary restriction (DR), which reduces the level of IGF-I and of other growth factors, has been associated with protection from diabetes, cancer, and cardiovascular diseases and deficiencies in GH signaling and IGF-I are strongly associated with protection from cancer and diabetes in both mice and humans, but their role in cardiac function and cardiovascular diseases is controversial. Here we review the link between growth factors, cardiac function and heart disease with focus on the cardioprotective and sensitizing effect of growth factors in both model organisms and humans. PMID:22499903

DOE Office of Scientific and Technical Information (OSTI.GOV)

Roat, C

A measurement of {Beta}({Lambda}{sub c}{sup +} {yields} pK{sup -} {pi}{sup +}) is presented based on data collected with the BaBar detector at the Stanford Linear Accelerator Center. Branching fraction measurements represent a large portion of what is known about short-lived particles, the strong force that binds them, and the weak force that causes them to decay. While the majority of branching fraction measurements are done as ratios between two decay modes, it is the absolute measurements of a few particular decay modes that set the scale for these relative measurements. The {Lambda}{sub c}{sup +} particle is one of the fourmore » weakly decaying hadrons into which more than 90% of the known heavy quark hadrons will eventually decay. Thus, an absolute measurement of the branching fraction for {Lambda}{sub c}{sup +} {yields} pK{sup -}{pi}{sup +} is important for many studies of the heavy quark sector, from spectroscopy to B meson decays. The number of produced {Lambda}{sub c}{sup +}'s is inferred from the number of events reconstructed with an antiproton and an accompanying D meson. The final result of {Beta}({Lambda}{sub c}{sup +} {yields} pK{sup -} {pi}{sup +}) = [6.12 {+-} 0.31(stat.) {+-} 0.42(syst.)]% represents more than a two-fold improvement in precision over the world average. The dominant source of systematic uncertainty is the irreducible background of {Xi}{sub c} baryons.« less

Search for the rare decay B→Kνν¯

NASA Astrophysics Data System (ADS)

Del Amo Sanchez, P.; Lees, J. P.; Poireau, V.; Prencipe, E.; Tisserand, V.; Garra Tico, J.; Grauges, E.; Martinelli, M.; Palano, A.; Pappagallo, M.; Eigen, G.; Stugu, B.; Sun, L.; Battaglia, M.; Brown, D. N.; Hooberman, B.; Kerth, L. T.; Kolomensky, Yu. G.; Lynch, G.; Osipenkov, I. L.; Tanabe, T.; Hawkes, C. M.; Watson, A. T.; Koch, H.; Schroeder, T.; Asgeirsson, D. J.; Hearty, C.; Mattison, T. S.; McKenna, J. A.; Khan, A.; Randle-Conde, A.; Blinov, V. E.; Buzykaev, A. R.; Druzhinin, V. P.; Golubev, V. B.; Onuchin, A. P.; Serednyakov, S. I.; Skovpen, Yu. I.; Solodov, E. P.; Todyshev, K. Yu.; Yushkov, A. N.; Bondioli, M.; Curry, S.; Kirkby, D.; Lankford, A. J.; Mandelkern, M.; Martin, E. C.; Stoker, D. P.; Atmacan, H.; Gary, J. W.; Liu, F.; Long, O.; Vitug, G. M.; Campagnari, C.; Hong, T. M.; Kovalskyi, D.; Richman, J. D.; Eisner, A. M.; Heusch, C. A.; Kroseberg, J.; Lockman, W. S.; Martinez, A. J.; Schalk, T.; Schumm, B. A.; Seiden, A.; Winstrom, L. O.; Cheng, C. H.; Doll, D. A.; Echenard, B.; Hitlin, D. G.; Ongmongkolkul, P.; Porter, F. C.; Rakitin, A. Y.; Andreassen, R.; Dubrovin, M. S.; Mancinelli, G.; Meadows, B. T.; Sokoloff, M. D.; Bloom, P. C.; Ford, W. T.; Gaz, A.; Nagel, M.; Nauenberg, U.; Smith, J. G.; Wagner, S. R.; Ayad, R.; Toki, W. H.; Jasper, H.; Karbach, T. M.; Merkel, J.; Petzold, A.; Spaan, B.; Wacker, K.; Kobel, M. J.; Schubert, K. R.; Schwierz, R.; Bernard, D.; Verderi, M.; Clark, P. J.; Playfer, S.; Watson, J. E.; Andreotti, M.; Bettoni, D.; Bozzi, C.; Calabrese, R.; Cecchi, A.; Cibinetto, G.; Fioravanti, E.; Franchini, P.; Luppi, E.; Munerato, M.; Negrini, M.; Petrella, A.; Piemontese, L.; Baldini-Ferroli, R.; Calcaterra, A.; de Sangro, R.; Finocchiaro, G.; Nicolaci, M.; Pacetti, S.; Patteri, P.; Peruzzi, I. M.; Piccolo, M.; Rama, M.; Zallo, A.; Contri, R.; Guido, E.; Lo Vetere, M.; Monge, M. R.; Passaggio, S.; Patrignani, C.; Robutti, E.; Tosi, S.; Bhuyan, B.; Prasad, V.; Lee, C. L.; Morii, M.; Adametz, A.; Marks, J.; Uwer, U.; Bernlochner, F. U.; Ebert, M.; Lacker, H. M.; Lueck, T.; Volk, A.; Dauncey, P. D.; Tibbetts, M.; Behera, P. K.; Mallik, U.; Chen, C.; Cochran, J.; Crawley, H. B.; Dong, L.; Meyer, W. T.; Prell, S.; Rosenberg, E. I.; Rubin, A. E.; Gao, Y. Y.; Gritsan, A. V.; Guo, Z. J.; Arnaud, N.; Davier, M.; Derkach, D.; Firmino da Costa, J.; Grosdidier, G.; Le Diberder, F.; Lutz, A. M.; Malaescu, B.; Perez, A.; Roudeau, P.; Schune, M. H.; Serrano, J.; Sordini, V.; Stocchi, A.; Wang, L.; Wormser, G.; Lange, D. J.; Wright, D. M.; Bingham, I.; Chavez, C. A.; Coleman, J. P.; Fry, J. R.; Gabathuler, E.; Gamet, R.; Hutchcroft, D. E.; Payne, D. J.; Touramanis, C.; Bevan, A. J.; di Lodovico, F.; Sacco, R.; Sigamani, M.; Cowan, G.; Paramesvaran, S.; Wren, A. C.; Brown, D. N.; Davis, C. L.; Denig, A. G.; Fritsch, M.; Gradl, W.; Hafner, A.; Alwyn, K. E.; Bailey, D.; Barlow, R. J.; Jackson, G.; Lafferty, G. D.; West, T. J.; Anderson, J.; Cenci, R.; Jawahery, A.; Roberts, D. A.; Simi, G.; Tuggle, J. M.; Dallapiccola, C.; Salvati, E.; Cowan, R.; Dujmic, D.; Fisher, P. H.; Sciolla, G.; Zhao, M.; Lindemann, D.; Patel, P. M.; Robertson, S. H.; Schram, M.; Biassoni, P.; Lazzaro, A.; Lombardo, V.; Palombo, F.; Stracka, S.; Cremaldi, L.; Godang, R.; Kroeger, R.; Sonnek, P.; Summers, D. J.; Nguyen, X.; Simard, M.; Taras, P.; de Nardo, G.; Monorchio, D.; Onorato, G.; Sciacca, C.; Raven, G.; Snoek, H. L.; Jessop, C. P.; Knoepfel, K. J.; Losecco, J. M.; Wang, W. F.; Corwin, L. A.; Honscheid, K.; Kass, R.; Morris, J. P.; Blount, N. L.; Brau, J.; Frey, R.; Igonkina, O.; Kolb, J. A.; Rahmat, R.; Sinev, N. B.; Strom, D.; Strube, J.; Torrence, E.; Castelli, G.; Feltresi, E.; Gagliardi, N.; Margoni, M.; Morandin, M.; Posocco, M.; Rotondo, M.; Simonetto, F.; Stroili, R.; Ben-Haim, E.; Bonneaud, G. R.; Briand, H.; Calderini, G.; Chauveau, J.; Hamon, O.; Leruste, Ph.; Marchiori, G.; Ocariz, J.; Prendki, J.; Sitt, S.; Biasini, M.; Manoni, E.; Rossi, A.; Angelini, C.; Batignani, G.; Bettarini, S.; Carpinelli, M.; Casarosa, G.; Cervelli, A.; Forti, F.; Giorgi, M. A.; Lusiani, A.; Neri, N.; Paoloni, E.; Rizzo, G.; Walsh, J. J.; Lopes Pegna, D.; Lu, C.; Olsen, J.; Smith, A. J. S.; Telnov, A. V.; Anulli, F.; Baracchini, E.; Cavoto, G.; Faccini, R.; Ferrarotto, F.; Ferroni, F.; Gaspero, M.; Li Gioi, L.; Mazzoni, M. A.; Piredda, G.; Renga, F.; Hartmann, T.; Leddig, T.; Schröder, H.; Waldi, R.; Adye, T.; Franek, B.; Olaiya, E. O.; Wilson, F. F.; Emery, S.; Hamel de Monchenault, G.; Vasseur, G.; Yèche, Ch.; Zito, M.; Allen, M. T.; Aston, D.; Bard, D. J.; Bartoldus, R.; Benitez, J. F.; Cartaro, C.; Convery, M. R.; Dorfan, J.; Dubois-Felsmann, G. P.; Dunwoodie, W.; Field, R. C.; Franco Sevilla, M.; Fulsom, B. G.; Gabareen, A. M.; Graham, M. T.; Grenier, P.; Hast, C.; Innes, W. R.; Kelsey, M. H.; Kim, H.; Kim, P.; Kocian, M. L.; Leith, D. W. G. S.; Li, S.; Lindquist, B.; Luitz, S.; Luth, V.; Lynch, H. L.; Macfarlane, D. B.; Marsiske, H.; Muller, D. R.; Neal, H.; Nelson, S.; O'Grady, C. P.; Ofte, I.; Perl, M.; Pulliam, T.; Ratcliff, B. N.; Roodman, A.; Salnikov, A. A.; Santoro, V.; Schindler, R. H.; Schwiening, J.; Snyder, A.; Su, D.; Sullivan, M. K.; Sun, S.; Suzuki, K.; Thompson, J. M.; Va'Vra, J.; Wagner, A. P.; Weaver, M.; West, C. A.; Wisniewski, W. J.; Wittgen, M.; Wright, D. H.; Wulsin, H. W.; Yarritu, A. K.; Young, C. C.; Ziegler, V.; Chen, X. R.; Park, W.; Purohit, M. V.; White, R. M.; Wilson, J. R.; Sekula, S. J.; Bellis, M.; Burchat, P. R.; Edwards, A. J.; Miyashita, T. S.; Ahmed, S.; Alam, M. S.; Ernst, J. A.; Pan, B.; Saeed, M. A.; Zain, S. B.; Guttman, N.; Soffer, A.; Lund, P.; Spanier, S. M.; Eckmann, R.; Ritchie, J. L.; Ruland, A. M.; Schilling, C. J.; Schwitters, R. F.; Wray, B. C.; Izen, J. M.; Lou, X. C.; Bianchi, F.; Gamba, D.; Pelliccioni, M.; Bomben, M.; Lanceri, L.; Vitale, L.; Lopez-March, N.; Martinez-Vidal, F.; Milanes, D. A.; Oyanguren, A.; Albert, J.; Banerjee, Sw.; Choi, H. H. F.; Hamano, K.; King, G. J.; Kowalewski, R.; Lewczuk, M. J.; Nugent, I. M.; Roney, J. M.; Sobie, R. J.; Gershon, T. J.; Harrison, P. F.; Latham, T. E.; Puccio, E. M. T.; Band, H. R.; Dasu, S.; Flood, K. T.; Pan, Y.; Prepost, R.; Vuosalo, C. O.; Wu, S. L.

2010-12-01

We present a search for the rare decays B+→K+νν¯ and B0→K0νν¯ using 459×106 BB¯ pairs collected with the BABAR detector at the SLAC National Accelerator Laboratory. Flavor-changing neutral-current decays such as these are forbidden at tree level but can occur through one-loop diagrams in the standard model (SM), with possible contributions from new physics at the same order. The presence of two neutrinos in the final state makes identification of signal events challenging, so reconstruction in the semileptonic decay channels B→D(*)lν of the B meson recoiling from the signal B is used to suppress backgrounds. We set an upper limit at the 90% confidence level (CL) of 1.3×10-5 on the total branching fraction for B+→K+νν¯, and 5.6×10-5 for B0→K0νν¯. We additionally report 90% CL upper limits on partial branching fractions in two ranges of dineutrino mass squared for B+→K+νν¯.

ω→π0γ* and ϕ→π0γ* transition form factors in dispersion theory

NASA Astrophysics Data System (ADS)

Schneider, Sebastian P.; Kubis, Bastian; Niecknig, Franz

2012-09-01

We calculate the ω→π0γ* and ϕ→π0γ* electromagnetic transition form factors based on dispersion theory, relying solely on a previous dispersive analysis of the corresponding three-pion decays and the pion vector form factor. We compare our findings to recent measurements of the ω→π0μ+μ- decay spectrum by the NA60 collaboration, and strongly encourage experimental investigation of the Okubo-Zweig-Iizuka forbidden ϕ→π0ℓ+ℓ- decays in order to understand the strong deviations from vector-meson dominance found in these transition form factors.

Some properties of human neuronal alpha 7 nicotinic acetylcholine receptors fused to the green fluorescent protein.

PubMed

Palma, Eleonora; Mileo, Anna M; Martinez-Torres, Ataulfo; Eusebi, Fabrizio; Miledi, Ricardo

2002-03-19

The functional properties and cellular localization of the human neuronal alpha7 nicotinic acetylcholine (AcCho) receptor (alpha7 AcChoR) and its L248T mutated (mut) form were investigated by expressing them alone or as gene fusions with the enhanced version of the green fluorescent protein (GFP). Xenopus oocytes injected with wild-type (wt), mutalpha7, or the chimeric subunit cDNAs expressed receptors that gated membrane currents when exposed to AcCho. As already known, AcCho currents generated by wtalpha7 receptors decay much faster than those elicited by the mutalpha7 receptors. Unexpectedly, the fusion of GFP to the wt and mutated alpha7 receptors led to opposite results: the AcCho-current decay of the wt receptors became slower, whereas that of the mutated receptors was accelerated. Furthermore, repetitive applications of AcCho led to a considerable "run-down" of the AcCho currents generated by mutalpha7-GFP receptors, whereas those of the wtalpha7-GFP receptors remained stable or increased in amplitude. The AcCho-current run-down of mutalpha7-GFP oocytes was accompanied by a marked decrease of alpha-bungarotoxin binding activity. Fluorescence, caused by the chimeric receptors expressed, was seen over the whole oocyte surface but was more intense and abundant in the animal hemisphere, whereas it was much weaker in the vegetal hemisphere. We conclude that fusion of GFP to wtalpha7 and mutalpha7 receptors provides powerful tools to study the distribution and function of alpha7 receptors. We also conclude that fused genes do not necessarily recapitulate all of the properties of the original receptors. This fact must be borne close in mind whenever reporter genes are attached to proteins.

Three-dimensional transient flow of spin-up in a filled cylinder with oblique gravity force

NASA Technical Reports Server (NTRS)

Hung, R. J.; Pan, H. L.

1995-01-01

Three-dimensional transient flow profiles of spin-up in a fully liquid filled cylinder from rest with gravity acceleration at various direction are numerically simulated and studied. Particular interests are concentrated on the development of temporary reverse flow zones and Ekman layer right after the impulsive start of spin-up from rest, and decay before the flow reaching to the solid rotation. Relationship of these flow developments and differences in the Reynolds numbers of the flow and its size selection of grid points concerning the numerical instabilities of flow computations are also discussed. In addition to the gravitational acceleration along the axial direction of the cylindrical container, a series of complicated flow profiles accompanied by three-dimensional transient flows with oblique gravitational acceleration has been studies.

Cannibalism versus funerary defleshing and disarticulation after a period of decay: comparisons of bone modifications from four prehistoric sites.

PubMed

Bello, Silvia M; Wallduck, Rosalind; Dimitrijević, Vesna; Živaljević, Ivana; Stringer, Chris B

2016-12-01

Humanly induced modifications on human and non-human bones from four archaeological sites of known funerary rituals (one interpreted as cannibalism and three interpreted as funerary defleshing and disarticulation after a period of decay) were analyzed to ascertain whether macromorphological and micromorphological characteristics of cut marks can be used to distinguish cannibalistic from secondary burial practices. Four collections were analyzed: the Magdalenian assemblage from Gough's Cave (UK) and the Mesolithic-Neolithic bone samples from Lepenski Vir, Padina and Vlasac (Serbia). A total of 647 cut marks (345 on human and 302 on non-human remains) were imaged and measured using an optical surface measurement system, the Alicona InfiniteFocus, housed at the Natural History Museum (London, UK). The frequency of cut marks at Gough's Cave exceeds 65%, while it is below 1% in the Serbian sites, and no human tooth marks and only one case of percussion damage have been observed on the three Serbian collections. The distribution of cut marks on human bones is comparable in the four assemblages. Cannibalized human remains, however, present a uniform cut mark distribution, which can be associated with disarticulation of persistent and labile articulations, and the scalping and filleting of muscles. For secondary burials where modification occurred after a period of decay, disarticulation marks are less common and the disarticulation of labile joints is rare. The micromorphometric analyses of cut marks on human and non-human remains suggest that cut marks produced when cleaning partially decayed bodies are significantly different from cut marks produced during butchery of fresh bodies. A distinction between cannibalism and secondary treatment of human bodies can be made based on frequency, distribution and micromorphometric characteristics of cut marks. © 2016 Wiley Periodicals, Inc.

Reducing cognitive skill decay and diagnostic error: theory-based practices for continuing education in health care.

PubMed

Weaver, Sallie J; Newman-Toker, David E; Rosen, Michael A

2012-01-01

Missed, delayed, or wrong diagnoses can have a severe impact on patients, providers, and the entire health care system. One mechanism implicated in such diagnostic errors is the deterioration of cognitive diagnostic skills that are used rarely or not at all over a prolonged period of time. Existing evidence regarding maintenance of effective cognitive reasoning skills in the clinical education, organizational training, and human factors literatures suggest that continuing education plays a critical role in mitigating and managing diagnostic skill decay. Recent models also underscore the role of system level factors (eg, cognitive decision support tools, just-in-time training opportunities) in supporting clinical reasoning process. The purpose of this manuscript is to offer a multidisciplinary review of cognitive models of clinical decision making skills in order to provide a list of best practices for supporting continuous improvement and maintenance of cognitive diagnostic processes through continuing education. Copyright © 2012 The Alliance for Continuing Education in the Health Professions, the Society for Academic Continuing Medical Education, and the Council on CME, Association for Hospital Medical Education.

Crystal Structure of Swine Vesicular Disease Virus and Implications for Host Adaptation

PubMed Central

Fry, Elizabeth E.; Knowles, Nick J.; Newman, John W. I.; Wilsden, Ginette; Rao, Zihe; King, Andrew M. Q.; Stuart, David I.

2003-01-01

Swine vesicular disease virus (SVDV) is an Enterovirus of the family Picornaviridae that causes symptoms indistinguishable from those of foot-and-mouth disease virus. Phylogenetic studies suggest that it is a recently evolved genetic sublineage of the important human pathogen coxsackievirus B5 (CBV5), and in agreement with this, it has been shown to utilize the coxsackie and adenovirus receptor (CAR) for cell entry. The 3.0-Å crystal structure of strain UK/27/72 SVDV (highly virulent) reveals the expected similarity in core structure to those of other picornaviruses, showing most similarity to the closest available structure to CBV5, that of coxsackievirus B3 (CBV3). Features that help to cement together and rigidify the protein subunits are extended in this virus, perhaps explaining its extreme tolerance of environmental factors. Using the large number of capsid sequences available for both SVDV and CBV5, we have mapped the amino acid substitutions that may have occurred during the supposed adaptation of SVDV to a new host onto the structure of SVDV and a model of the SVDV/CAR complex generated by reference to the cryo-electron microscopy-visualized complex of CBV3 and CAR. The changes fall into three clusters as follows: one lines the fivefold pore, a second maps to the CAR-binding site and partially overlaps the site for decay accelerating factor (DAF) to bind to echovirus 7 (ECHO7), and the third lies close to the fivefold axis, where the low-density lipoprotein receptor binds to the minor group of rhinoviruses. Later changes in SVDV (post-1971) map to the first two clusters and may, by optimizing recognition of a pig CAR and/or DAF homologue, have improved the adaptation of the virus to pigs. PMID:12692248

Human choice among five alternatives when reinforcers decay.

PubMed

Rothstein, Jacob B; Jensen, Greg; Neuringer, Allen

2008-06-01

Human participants played a computer game in which choices among five alternatives were concurrently reinforced according to dependent random-ratio schedules. "Dependent" indicates that choices to any of the wedges activated the random-number generators governing reinforcers on all five alternatives. Two conditions were compared. In the hold condition, once scheduled, a reinforcer - worth a constant five points - remained available until it was collected. In the decay condition, point values decreased with intervening responses, i.e., rapid collection was differentially reinforced. Slopes of matching functions were higher in the decay than hold condition. However inter-subject variability was high in both conditions.

QCD in heavy quark production and decay

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wiss, J.

1997-06-01

The author discusses how QCD is used to understand the physics of heavy quark production and decay dynamics. His discussion of production dynamics primarily concentrates on charm photoproduction data which are compared to perturbative QCD calculations which incorporate fragmentation effects. He begins his discussion of heavy quark decay by reviewing data on charm and beauty lifetimes. Present data on fully leptonic and semileptonic charm decay are then reviewed. Measurements of the hadronic weak current form factors are compared to the nonperturbative QCD-based predictions of Lattice Gauge Theories. He next discusses polarization phenomena present in charmed baryon decay. Heavy Quark Effectivemore » Theory predicts that the daughter baryon will recoil from the charmed parent with nearly 100% left-handed polarization, which is in excellent agreement with present data. He concludes by discussing nonleptonic charm decay which is traditionally analyzed in a factorization framework applicable to two-body and quasi-two-body nonleptonic decays. This discussion emphasizes the important role of final state interactions in influencing both the observed decay width of various two-body final states as well as modifying the interference between interfering resonance channels which contribute to specific multibody decays. 50 refs., 77 figs.« less

Fluorosilicone and silicone o-ring aging study.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bernstein, Robert; Gillen, Kenneth T.

2007-10-01

Fluorosilicone o-ring aging studies were performed. These studies examined the compressive force loss of fluorosilicone o-rings at accelerated (elevated) temperatures and were then used to make predictions about force loss at room temperature. The results were non-Arrhenius with evidence for a lowering in Arrhenius activation energies as the aging temperature was reduced. The compression set of these fluorosilicone o-rings was found to have a reasonably linear correlation with the force loss. The aging predictions based on using the observed curvature of the Arrhenius aging plots were validated by field aged o-rings that yielded degradation values reasonably close to the predictions.more » Compression set studies of silicone o-rings from a previous study resulted in good correlation to the force loss predictions for the fluorosilicone o-rings from this study. This resulted in a preliminary conclusion that an approximately linear correlation exists between compression set and force decay values for typical fluorosilicone and silicone materials, and that the two materials age at similar rates at low temperatures. Interestingly, because of the observed curvature of the Arrhenius plots available from longer-term, lower temperature accelerated exposures, both materials had faster force decay curves (and correspondingly faster buildup of compression set) at room temperature than anticipated from typical high-temperature exposures. A brief study on heavily filled conducting silicone o-rings resulted in data that deviated from the linear relationship, implying that a degree of caution must be exercised about any general statement relating force decay and compression set.« less

Turbo-SMT: Accelerating Coupled Sparse Matrix-Tensor Factorizations by 200×

PubMed Central

Papalexakis, Evangelos E.; Faloutsos, Christos; Mitchell, Tom M.; Talukdar, Partha Pratim; Sidiropoulos, Nicholas D.; Murphy, Brian

2015-01-01

How can we correlate the neural activity in the human brain as it responds to typed words, with properties of these terms (like ‘edible’, ‘fits in hand’)? In short, we want to find latent variables, that jointly explain both the brain activity, as well as the behavioral responses. This is one of many settings of the Coupled Matrix-Tensor Factorization (CMTF) problem. Can we accelerate any CMTF solver, so that it runs within a few minutes instead of tens of hours to a day, while maintaining good accuracy? We introduce TURBO-SMT, a meta-method capable of doing exactly that: it boosts the performance of any CMTF algorithm, by up to 200×, along with an up to 65 fold increase in sparsity, with comparable accuracy to the baseline. We apply TURBO-SMT to BRAINQ, a dataset consisting of a (nouns, brain voxels, human subjects) tensor and a (nouns, properties) matrix, with coupling along the nouns dimension. TURBO-SMT is able to find meaningful latent variables, as well as to predict brain activity with competitive accuracy. PMID:26473087

Orthopositronium decay form factors and two-photon correlations

DOE Office of Scientific and Technical Information (OSTI.GOV)

Adkins, Gregory S.; Droz, Daniel R.; Rastawicki, Dominik

2010-04-15

We give results for the orthopositronium decay form factors through one-loop order. We use the form factors to calculate momentum correlations of the final-state photons and , including one-loop corrections, for ensembles of initial orthopositronium atoms having arbitrary polarization.

Astronaut Risk Levels During Crew Module (CM) Land Landing

NASA Technical Reports Server (NTRS)

Lawrence, Charles; Carney, Kelly S.; Littell, Justin

2007-01-01

The NASA Engineering Safety Center (NESC) is investigating the merits of water and land landings for the crew exploration vehicle (CEV). The merits of these two options are being studied in terms of cost and risk to the astronauts, vehicle, support personnel, and general public. The objective of the present work is to determine the astronaut dynamic response index (DRI), which measures injury risks. Risks are determined for a range of vertical and horizontal landing velocities. A structural model of the crew module (CM) is developed and computational simulations are performed using a transient dynamic simulation analysis code (LS-DYNA) to determine acceleration profiles. Landing acceleration profiles are input in a human factors model that determines astronaut risk levels. Details of the modeling approach, the resulting accelerations, and astronaut risk levels are provided.

High-precision branching ratio measurement for the superallowed β+ emitter Ga62

NASA Astrophysics Data System (ADS)

Finlay, P.; Ball, G. C.; Leslie, J. R.; Svensson, C. E.; Towner, I. S.; Austin, R. A. E.; Bandyopadhyay, D.; Chaffey, A.; Chakrawarthy, R. S.; Garrett, P. E.; Grinyer, G. F.; Hackman, G.; Hyland, B.; Kanungo, R.; Leach, K. G.; Mattoon, C. M.; Morton, A. C.; Pearson, C. J.; Phillips, A. A.; Ressler, J. J.; Sarazin, F.; Savajols, H.; Schumaker, M. A.; Wong, J.

2008-08-01

A high-precision branching ratio measurement for the superallowed β+ decay of Ga62 was performed at the Isotope Separator and Accelerator (ISAC) radioactive ion beam facility. The 8π spectrometer, an array of 20 high-purity germanium detectors, was employed to detect the γ rays emitted following Gamow-Teller and nonanalog Fermi β+ decays of Ga62, and the SCEPTAR plastic scintillator array was used to detect the emitted β particles. Thirty γ rays were identified following Ga62 decay, establishing the superallowed branching ratio to be 99.858(8)%. Combined with the world-average half-life and a recent high-precision Q-value measurement for Ga62, this branching ratio yields an ft value of 3074.3±1.1 s, making Ga62 among the most precisely determined superallowed ft values. Comparison between the superallowed ft value determined in this work and the world-average corrected F tmacr value allows the large nuclear-structure-dependent correction for Ga62 decay to be experimentally determined from the CVC hypothesis to better than 7% of its own value, the most precise experimental determination for any superallowed emitter. These results provide a benchmark for the refinement of the theoretical description of isospin-symmetry breaking in A⩾62 superallowed decays.

Evidence for B{sup 0}{yields}{rho}{sup 0}{rho}{sup 0} Decays and Implications for the Cabibbo-Kobayashi-Maskawa Angle {alpha}

DOE Office of Scientific and Technical Information (OSTI.GOV)

Aubert, B.; Bona, M.; Boutigny, D.

2007-03-16

We search for the decays B{sup 0}{yields}{rho}{sup 0}{rho}{sup 0}, B{sup 0}{yields}{rho}{sup 0}f{sub 0}(980), and B{sup 0}{yields}f{sub 0}(980)f{sub 0}(980) in a sample of about 384x10{sup 6} {upsilon}(4S){yields}BB decays collected with the BABAR detector at the PEP-II asymmetric-energy e{sup +}e{sup -} collider at Stanford Linear Accelerator Center. We find evidence for B{sup 0}{yields}{rho}{sup 0}{rho}{sup 0} with 3.5{sigma} significance and measure the branching fraction B=(1.07{+-}0.33{+-}0.19)x10{sup -6} and longitudinal polarization fraction f{sub L}=0.87{+-}0.13{+-}0.04, where the first uncertainty is statistical, and the second is systematic. The uncertainty on the Cabibbo-Kobayashi-Maskawa quark-mixing matrix unitarity angle {alpha} due to penguin contributions in B{yields}{rho}{rho} decays is 18 deg.more » at the 1{sigma} level. We also set upper limits on the B{sup 0}{yields}{rho}{sup 0}f{sub 0}(980) and B{sup 0}{yields}f{sub 0}(980)f{sub 0}(980) decay rates.« less

On the Radio-emitting Particles of the Crab Nebula: Stochastic Acceleration Model

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tanaka, Shuta J.; Asano, Katsuaki, E-mail: sjtanaka@center.konan-u.ac.jp

The broadband emission of pulsar wind nebulae (PWNe) is well described by non-thermal emissions from accelerated electrons and positrons. However, the standard shock acceleration model of PWNe does not account for the hard spectrum in radio wavelengths. The origin of the radio-emitting particles is also important to determine the pair production efficiency in the pulsar magnetosphere. Here, we propose a possible resolution for the particle energy distribution in PWNe; the radio-emitting particles are not accelerated at the pulsar wind termination shock but are stochastically accelerated by turbulence inside PWNe. We upgrade our past one-zone spectral evolution model to include themore » energy diffusion, i.e., the stochastic acceleration, and apply the model to the Crab Nebula. A fairly simple form of the energy diffusion coefficient is assumed for this demonstrative study. For a particle injection to the stochastic acceleration process, we consider the continuous injection from the supernova ejecta or the impulsive injection associated with supernova explosion. The observed broadband spectrum and the decay of the radio flux are reproduced by tuning the amount of the particle injected to the stochastic acceleration process. The acceleration timescale and the duration of the acceleration are required to be a few decades and a few hundred years, respectively. Our results imply that some unveiled mechanisms, such as back reaction to the turbulence, are required to make the energies of stochastically and shock-accelerated particles comparable.« less

Immunostimulation effect of jellyfish collagen.

PubMed

Sugahara, Takuya; Ueno, Masashi; Goto, Yoko; Shiraishi, Ryusuke; Doi, Mikiharu; Akiyama, Koichi; Yamauchi, Satoshi

2006-09-01

Certain edible large jellyfishes belonging to the order Rhizostomeae are consumed in large quantities in China and Japan. The exumbrella part of the edible jellyfish Stomolophus nomurai was cut and soaked in dilute hydrochloric acid solution (pH 3.0) for 12 h, and heated at 121 degrees C for 20 min. The immunostimulation effects of the jellyfish extract were examined. The jellyfish extract enhanced IgM production of human hybridoma HB4C5 cells 34-fold. IgM and IgG production of human peripheral blood lymphocytes (PBL) were also accelerated, 2.8- and 1.4-fold respectively. Moreover, production of interferon (IFN)-gamma and tumor necrosis factor (TNF)-alpha by human PBL was stimulated 100- and 17-fold respectively. Collagenase treatment inactivated the immunostimulation activity of the jellyfish extract. In addition, purified collagen from bovine Achilles' tendon accelerated IgM production of hybridoma cells. These facts mean that collagen has an immunostimulation effect, and that the active substance in jellyfish extract is collagen.

Shapes of cometary isophotes with Maxwellian distribution of initial velocities for neutral molecules

NASA Astrophysics Data System (ADS)

Žáček, P.; Wolf, M.

2017-10-01

This paper contains necessary modification of Bessel's equations for the axial cometary syndyne. This correction provides the accurate values of molecular acceleration in a cometary tail and precise values of decay constants for radiating molecules and their lifetimes. In consequence the hypothesis of the predissociation of molecules seems to be useless.

Principal Component Analysis of Microbial Community Data from an Accelerated Decay Cellar Test

Treesearch

Grant T. Kirker; Patricia K. Lebow

2014-01-01

Analysis of microbial communities is a valuable tool for characterization and identification of microbes in a myriad of environments. We are currently using the molecular method terminal restriction fragment length polymorphism (T-RFLP) analysis to characterize changes in bacterial and fungal communities on treated and untreated wood in soil. T-RFLP uses fluorescently...

Performance of two solid fumigants in covered bridges

Treesearch

Matthew J. Konkler; Mark A. Newbill; Stan Lebow; Jeffrey J. Morrell

2017-01-01

The potential for two solid wood fumigants, dazomet and methylisothiocyanate (MITC), to move through wood at levels sufficient to arrest decay in covered bridges was assessed. Dazomet alone failed to decompose to MITC and move into the wood at effective levels, probably because too little moisture was available for breakdown. Adding a copper accelerant improved dazomet...

The photochemical reaction cycle and photoinduced proton transfer of sensory rhodopsin II (Phoborhodopsin) from Halobacterium salinarum.

PubMed

Tamogami, Jun; Kikukawa, Takashi; Ikeda, Yoichi; Takemura, Ayaka; Demura, Makoto; Kamo, Naoki

2010-04-07

Sensory rhodopsin II (HsSRII, also called phoborhodopsin) is a negative phototaxis receptor of Halobacterium salinarum, a bacterium that avoids blue-green light. In this study, we expressed the protein in Escherichia coli cells, and reconstituted the purified protein with phosphatidylcholine. The reconstituted HsSRII was stable. We examined the photocycle by flash-photolysis spectroscopy in the time range of milliseconds to seconds, and measured proton uptake/release using a transparent indium-tin oxide electrode. The pKa of the counterion of the Schiff base, Asp(73), was 3.0. Below pH 3, the depleted band was observed on flash illumination, but the positive band in the difference spectra was not found. Above pH 3, the basic photocycle was HsSRII (490) --> M (350) --> O (520) --> Y (490) --> HsSRII, where the numbers in parentheses are the maximum wavelengths. The decay rate of O-intermediate and Y-intermediate were pH-independent, whereas the M-intermediate decay was pH-dependent. For 3 < pH < 4.5, the M-decay was one phase, and the rate decreased with an increase in pH. For 4.5 < pH < 6.5, the decay was one phase with pH-independent rates, and azide markedly accelerated the M-decay. These findings suggest the existence of a protonated amino acid residue (X-H) that may serve as a proton relay to reprotonate the Schiff base. Above pH 6.5, the M-decay showed two phases. The fast M-decay was pH-independent and originated from the molecule having a protonated X-H, and the slow M-decay originated from the molecule having a deprotonated X, in which the proton came directly from the outside. The analysis yielded a value of 7.5 for the pKa of X-H. The proton uptake and release occurred during M-decay and O-decay, respectively. Copyright (c) 2010 Biophysical Society. Published by Elsevier Inc. All rights reserved.

When a tree falls: Controls on wood decay predict standing dead tree fall and new risks in changing forests.

PubMed

Oberle, Brad; Ogle, Kiona; Zanne, Amy E; Woodall, Christopher W

2018-01-01

When standing dead trees (snags) fall, they have major impacts on forest ecosystems. Snag fall can redistribute wildlife habitat and impact public safety, while governing important carbon (C) cycle consequences of tree mortality because ground contact accelerates C emissions during deadwood decay. Managing the consequences of altered snag dynamics in changing forests requires predicting when snags fall as wood decay erodes mechanical resistance to breaking forces. Previous studies have pointed to common predictors, such as stem size, degree of decay and species identity, but few have assessed the relative strength of underlying mechanisms driving snag fall across biomes. Here, we analyze nearly 100,000 repeated snag observations from boreal to subtropical forests across the eastern United States to show that wood decay controls snag fall in ways that could generate previously unrecognized forest-climate feedback. Warmer locations where wood decays quickly had much faster rates of snag fall. The effect of temperature on snag fall was so strong that in a simple forest C model, anticipated warming by mid-century reduced snag C by 22%. Furthermore, species-level differences in wood decay resistance (durability) accurately predicted the timing of snag fall. Differences in half-life for standing dead trees were similar to expected differences in the service lifetimes of wooden structures built from their timber. Strong effects of temperature and wood durability imply future forests where dying trees fall and decay faster than at present, reducing terrestrial C storage and snag-dependent wildlife habitat. These results can improve the representation of forest C cycling and assist forest managers by helping predict when a dead tree may fall.

When a tree falls: Controls on wood decay predict standing dead tree fall and new risks in changing forests

PubMed Central

Ogle, Kiona; Zanne, Amy E.; Woodall, Christopher W.

2018-01-01

When standing dead trees (snags) fall, they have major impacts on forest ecosystems. Snag fall can redistribute wildlife habitat and impact public safety, while governing important carbon (C) cycle consequences of tree mortality because ground contact accelerates C emissions during deadwood decay. Managing the consequences of altered snag dynamics in changing forests requires predicting when snags fall as wood decay erodes mechanical resistance to breaking forces. Previous studies have pointed to common predictors, such as stem size, degree of decay and species identity, but few have assessed the relative strength of underlying mechanisms driving snag fall across biomes. Here, we analyze nearly 100,000 repeated snag observations from boreal to subtropical forests across the eastern United States to show that wood decay controls snag fall in ways that could generate previously unrecognized forest-climate feedback. Warmer locations where wood decays quickly had much faster rates of snag fall. The effect of temperature on snag fall was so strong that in a simple forest C model, anticipated warming by mid-century reduced snag C by 22%. Furthermore, species-level differences in wood decay resistance (durability) accurately predicted the timing of snag fall. Differences in half-life for standing dead trees were similar to expected differences in the service lifetimes of wooden structures built from their timber. Strong effects of temperature and wood durability imply future forests where dying trees fall and decay faster than at present, reducing terrestrial C storage and snag-dependent wildlife habitat. These results can improve the representation of forest C cycling and assist forest managers by helping predict when a dead tree may fall. PMID:29742158

A dispersive treatment of decays

NASA Astrophysics Data System (ADS)

Stoffer, Peter; Colangelo, Gilberto; Passemar, Emilie

2017-01-01

decays have several features of interest: they allow an accurate measurement of ππ-scattering lengths; the decay is the best source for the determination of some low-energy constants of chiral perturbation theory (χPT) one form factor of the decay is connected to the chiral anomaly. We present the results of our dispersive analysis of decays, which provides a resummation of ππ- and Kπ-rescattering effects. The free parameters of the dispersion relation are fitted to the data of the high-statistics experiments E865 and NA48/2. By matching to χPT at NLO and NNLO, we determine the low-energy constants and . In contrast to a pure chiral treatment, the dispersion relation describes the observed curvature of one of the form factors, which we understand as an effect of rescattering beyond NNLO.

High current H{sub 2}{sup +} cyclotrons for neutrino physics: The IsoDAR and DAE{delta}ALUS projects

DOE Office of Scientific and Technical Information (OSTI.GOV)

Alonso, Jose R.; Collaboration: DAE delta ALUS Collaboration

2013-04-19

Using H{sub 2}{sup +} ions is expected to mitigate the two major impediments to accelerating very high currents in cyclotrons, due to lower space charge at injection, and stripping extraction. Planning for peak currents of 10 particle milliamps at 800 MeV/amu, these cyclotrons can generate adequate neutrino fluxes for Decay-At-Rest (DAR) studies of neutrino oscillation and CP violation. The Injector Cyclotron, at 60 MeV/amu can also provide adequate fluxes of electron antineutrinos from {sup 8}Li decay for sterile neutrino searches in existing liquid scintillator detectors at Kam LAND or SNO+. This paper outlines programs for designing and building these machines.

Study of the Rare Decay K L → π 0γγ at KTeV

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang, Jianbo

2007-01-01

The authors study on the rare decay K L → π 0γγ, measure a V, and branching ratio by analyzing 96, 97 and 99 data. The measurements were taken by KTeV at Fermi National Accelerator Laboratory. After all cuts, they have 1982 K L → π 0γγ candidate. The background level is estimated as 30%. K L → π 0γγ branching ratio is measured as (1.29 ± 0.03(stat) ± 0.04(sys)) x 10 -6. By using D'Ambrosio's theory to fit a V, a V = -(-0.31 ± 0.05(stat) ± 0.07(sys)).

Comprehensive identification and analysis of human accelerated regulatory DNA

PubMed Central

Gittelman, Rachel M.; Hun, Enna; Ay, Ferhat; Madeoy, Jennifer; Pennacchio, Len; Noble, William S.; Hawkins, R. David; Akey, Joshua M.

2015-01-01

It has long been hypothesized that changes in gene regulation have played an important role in human evolution, but regulatory DNA has been much more difficult to study compared with protein-coding regions. Recent large-scale studies have created genome-scale catalogs of DNase I hypersensitive sites (DHSs), which demark potentially functional regulatory DNA. To better define regulatory DNA that has been subject to human-specific adaptive evolution, we performed comprehensive evolutionary and population genetics analyses on over 18 million DHSs discovered in 130 cell types. We identified 524 DHSs that are conserved in nonhuman primates but accelerated in the human lineage (haDHS), and estimate that 70% of substitutions in haDHSs are attributable to positive selection. Through extensive computational and experimental analyses, we demonstrate that haDHSs are often active in brain or neuronal cell types; play an important role in regulating the expression of developmentally important genes, including many transcription factors such as SOX6, POU3F2, and HOX genes; and identify striking examples of adaptive regulatory evolution that may have contributed to human-specific phenotypes. More generally, our results reveal new insights into conserved and adaptive regulatory DNA in humans and refine the set of genomic substrates that distinguish humans from their closest living primate relatives. PMID:26104583

A New Mechanism of Magnetic Field Generation in Supernova Shock Waves and its Implication for Cosmic Ray Acceleration

NASA Astrophysics Data System (ADS)

Diamond, Patrick

2005-10-01

SNR shocks are the most probable source of galactic cosmic rays. We discuss the diffusive acceleration mechanism in terms of its potential to accelerate CRs to 10^18 eV, as observations imply. One possibility, currently discussed in the literature, is to resonantly generate a turbulent magnetic field via accelerated particles in excess of the background field. We indicate some difficulties of this scenario and suggest a different possibility, which is based on the generation of Alfven waves at the gyroradius scale at the background field level, with a subsequent transfer to longer scales via interaction with strong acoustic turbulence in the shock precursor. The acoustic turbulence in turn, may be generated by Drury instability or by parametric instability of the Alfven (A) waves. The essential idea is an A-->A+S decay instability process, where one of the interacting scatterers (i.e. the sound, or S-waves) are driven by the Drury instability process. This rapidly generates longer wavelength Alfven waves, which in turn resonate with high energy CRs thus binding them to the shock and enabling their further acceleration.

Electrical Engineering in Los Alamos Neutron Science Center Accelerator

DOE Office of Scientific and Technical Information (OSTI.GOV)

Silva, Michael James

The field of electrical engineering plays a significant role in particle accelerator design and operations. Los Alamos National Laboratories LANSCE facility utilizes the electrical energy concepts of power distribution, plasma generation, radio frequency energy, electrostatic acceleration, signals and diagnostics. The culmination of these fields produces a machine of incredible potential with uses such as isotope production, neutron spallation, neutron imaging and particle analysis. The key isotope produced in LANSCE isotope production facility is Strontium-82 which is utilized for medical uses such as cancer treatment and positron emission tomography also known as PET scans. Neutron spallation is one of the verymore » few methods used to produce neutrons for scientific research the other methods are natural decay of transuranic elements from nuclear reactors. Accelerator produce neutrons by accelerating charged particles into neutron dense elements such as tungsten imparting a neutral particle with kinetic energy, this has the benefit of producing a large number of neutrons as well as minimizing the waste generated. Utilizing the accelerator scientist can gain an understanding of how various particles behave and interact with matter to better understand the natural laws of physics and the universe around us.« less

Restoration of Tidal Flow to Impounded Salt Marsh Exerts Mixed Effect on Leaf Litter Decomposition

NASA Astrophysics Data System (ADS)

Henry, B. A.; Schade, J. D.; Foreman, K.

2015-12-01

Salt marsh impoundments (e.g. roads, levees) disconnect marshes from ocean tides, which impairs ecosystem services and often promotes invasive species. Numerous restoration projects now focus on removing impoundments. Leaf litter decomposition is a central process in salt marsh carbon and nutrient cycles, and this study investigated the extent to which marsh restoration alters litter decomposition rates. We considered three environmental factors that can potentially change during restoration: salinity, tidal regime, and dominant plant species. A one-month field experiment (Cape Cod, MA) measured decay of litter bags in impounded, restored, and natural marshes under ambient conditions. A two-week lab experiment measured litter decay in controlled incubations under experimental treatments for salinity (1ppt and 30 ppt), tidal regime (inundated and 12 hr wet-dry cycles), and plant species (native Spartina alterniflora and invasive Phragmites australis). S. alterniflora decomposed faster in situ than P. australis (14±1.0% mass loss versus 0.74±0.69%). Corroborating this difference in decomposition, S. alterniflora supported greater microbial respiration during lab incubation, measured as CO2 flux from leaf litter and biological oxygen demand of water containing leached organic matter (OM). However, nutrient analysis of plant tissue and leached OM show P. australis released more nitrogen than S. alterniflora. Low salinity treatments in both lab and field experiments decayed more rapidly than high salinity treatments, suggesting that salinity inhibited microbial activity. Manipulation of inundation regime did not affect decomposition. These findings suggest the reintroduction of tidal flow to an impounded salt marsh can have mixed effects; recolonization by the native cordgrass could supply labile OM to sediment and slow carbon sequestration, while an increase in salinity might inhibit decomposition and accelerate sequestration.

Does increasing pressure always accelerate the condensed material decay initiated through bimolecular reactions? A case of the thermal decomposition of TKX-50 at high pressures.

PubMed

Lu, Zhipeng; Zeng, Qun; Xue, Xianggui; Zhang, Zengming; Nie, Fude; Zhang, Chaoyang

2017-08-30

Performances and behaviors under high temperature-high pressure conditions are fundamentals for many materials. We study in the present work the pressure effect on the thermal decomposition of a new energetic ionic salt (EIS), TKX-50, by confining samples in a diamond anvil cell, using Raman spectroscopy measurements and ab initio simulations. As a result, we find a quadratic increase in decomposition temperature (T d ) of TKX-50 with increasing pressure (P) (T d = 6.28P 2 + 12.94P + 493.33, T d and P in K and GPa, respectively, and R 2 = 0.995) and the decomposition under various pressures initiated by an intermolecular H-transfer reaction (a bimolecular reaction). Surprisingly, this finding is contrary to a general observation about the pressure effect on the decomposition of common energetic materials (EMs) composed of neutral molecules: increasing pressure will impede the decomposition if it starts from a bimolecular reaction. Our results also demonstrate that increasing pressure impedes the H-transfer via the enhanced long-range electrostatic repulsion of H +δ H +δ of neighboring NH 3 OH + , with blue shifts of the intermolecular H-bonds. And the subsequent decomposition of the H-transferred intermediates is also suppressed, because the decomposition proceeds from a bimolecular reaction to a unimolecular one, which is generally prevented by compression. These two factors are the basic root for which the decomposition retarded with increasing pressure of TKX-50. Therefore, our finding breaks through the previously proposed concept that, for the condensed materials, increasing pressure will accelerate the thermal decomposition initiated by bimolecular reactions, and reveals a distinct mechanism of the pressure effect on thermal decomposition. That is to say, increasing pressure does not always promote the condensed material decay initiated through bimolecular reactions. Moreover, such a mechanism may be feasible to other EISs due to the similar intermolecular interactions.

Stochastic shock response spectrum decomposition method based on probabilistic definitions of temporal peak acceleration, spectral energy, and phase lag distributions of mechanical impact pyrotechnic shock test data

NASA Astrophysics Data System (ADS)

Hwang, James Ho-Jin; Duran, Adam

2016-08-01

Most of the times pyrotechnic shock design and test requirements for space systems are provided in Shock Response Spectrum (SRS) without the input time history. Since the SRS does not describe the input or the environment, a decomposition method is used to obtain the source time history. The main objective of this paper is to develop a decomposition method producing input time histories that can satisfy the SRS requirement based on the pyrotechnic shock test data measured from a mechanical impact test apparatus. At the heart of this decomposition method is the statistical representation of the pyrotechnic shock test data measured from the MIT Lincoln Laboratory (LL) designed Universal Pyrotechnic Shock Simulator (UPSS). Each pyrotechnic shock test data measured at the interface of a test unit has been analyzed to produce the temporal peak acceleration, Root Mean Square (RMS) acceleration, and the phase lag at each band center frequency. Maximum SRS of each filtered time history has been calculated to produce a relationship between the input and the response. Two new definitions are proposed as a result. The Peak Ratio (PR) is defined as the ratio between the maximum SRS and the temporal peak acceleration at each band center frequency. The ratio between the maximum SRS and the RMS acceleration is defined as the Energy Ratio (ER) at each band center frequency. Phase lag is estimated based on the time delay between the temporal peak acceleration at each band center frequency and the peak acceleration at the lowest band center frequency. This stochastic process has been applied to more than one hundred pyrotechnic shock test data to produce probabilistic definitions of the PR, ER, and the phase lag. The SRS is decomposed at each band center frequency using damped sinusoids with the PR and the decays obtained by matching the ER of the damped sinusoids to the ER of the test data. The final step in this stochastic SRS decomposition process is the Monte Carlo (MC) simulation. The MC simulation identifies combinations of the PR and decays that can meet the SRS requirement at each band center frequency. Decomposed input time histories are produced by summing the converged damped sinusoids with the MC simulation of the phase lag distribution.

Geographic Analysis and Monitoring Program

USGS Publications Warehouse

Campbell, Jon C.

2007-01-01

The surface of the Earth is changing rapidly, at local, regional, national, and global scales, with significant repercussions for people, the economy, and the environment. Some changes have natural causes, such as wildland fires or hurricanes, while other changes on the land, such as resource extraction, agricultural practices, and urban growth, are human-induced processes. There are other types of changes that are a combination of natural and human-induced factors; landslides and floods, for example, are fundamentally natural processes that are often intensified or accelerated by human land use practices. Whatever their cause, land-surface changes can have profound environmental and economic impacts.

Measurement of direct f0(980) photoproduction on the proton.

PubMed

Battaglieri, M; De Vita, R; Szczepaniak, A P; Adhikari, K P; Aghasyan, M; Amaryan, M J; Ambrozewicz, P; Anghinolfi, M; Asryan, G; Avakian, H; Bagdasaryan, H; Baillie, N; Ball, J P; Baltzell, N A; Batourine, V; Bedlinskiy, I; Bellis, M; Benmouna, N; Berman, B L; Bibrzycki, L; Biselli, A S; Bookwalter, C; Bouchigny, S; Boiarinov, S; Bradford, R; Branford, D; Briscoe, W J; Brooks, W K; Bültmann, S; Burkert, V D; Calarco, J R; Careccia, S L; Carman, D S; Casey, L; Chen, S; Cheng, L; Clinton, E; Cole, P L; Collins, P; Crabb, D; Crannell, H; Crede, V; Cummings, J P; Dale, D; Daniel, A; Dashyan, N; De Masi, R; De Sanctis, E; Degtyarenko, P V; Deur, A; Dhamija, S; Dharmawardane, K V; Dickson, R; Djalali, C; Dodge, G E; Donnelly, J; Doughty, D; Dugger, M; Dzyubak, O P; Egiyan, H; Egiyan, K S; El Fassi, L; Elouadrhiri, L; Eugenio, P; Fedotov, G; Fersch, R; Forest, T A; Fradi, A; Gabrielyan, M Y; Gan, L; Garçon, M; Gasparian, A; Gavalian, G; Gevorgyan, N; Gilfoyle, G P; Giovanetti, K L; Girod, F X; Glamazdin, O; Goett, J; Goetz, J T; Gohn, W; Golovatch, E; Gordon, C I O; Gothe, R W; Graham, L; Griffioen, K A; Guidal, M; Guler, N; Guo, L; Gyurjyan, V; Hadjidakis, C; Hafidi, K; Hakobyan, H; Hakobyan, R S; Hanretty, C; Hardie, J; Hassall, N; Heddle, D; Hersman, F W; Hicks, K; Hleiqawi, I; Holtrop, M; Hyde, C E; Ilieva, Y; Ireland, D G; Ishkhanov, B S; Isupov, E L; Ito, M M; Jenkins, D; Jo, H S; Johnstone, J R; Joo, K; Juengst, H G; Kageya, T; Kalantarians, N; Keller, D; Kellie, J D; Khandaker, M; Khetarpal, P; Kim, W; Klein, A; Klein, F J; Klimenko, A V; Konczykowski, P; Kossov, M; Krahn, Z; Kramer, L H; Kubarovsky, V; Kuhn, J; Kuhn, S E; Kuleshov, S V; Kuznetsov, V; Lachniet, J; Laget, J M; Langheinrich, J; Lawrence, D; Lee, T; Lesniak, L; Li, Ji; Livingston, K; Lowry, M; Lu, H Y; Maccormick, M; Malace, S; Markov, N; Mattione, P; McCracken, M E; McKinnon, B; Mecking, B A; Melone, J J; Mestayer, M D; Meyer, C A; Mibe, T; Mikhailov, K; Mineeva, T; Minehart, R; Mirazita, M; Miskimen, R; Mochalov, V; Mokeev, V; Moreno, B; Moriya, K; Morrow, S A; Moteabbed, M; Munevar, E; Mutchler, G S; Nadel-Turonski, P; Nakagawa, I; Nasseripour, R; Niccolai, S; Niculescu, G; Niculescu, I; Niczyporuk, B B; Niroula, M R; Niyazov, R A; Nozar, M; Osipenko, M; Ostrovidov, A I; Park, K; Park, S; Pasyuk, E; Paris, M; Paterson, C; Pereira, S Anefalos; Pierce, J; Pivnyuk, N; Pocanic, D; Pogorelko, O; Pozdniakov, S; Price, J W; Prok, Y; Protopopescu, D; Raue, B A; Riccardi, G; Ricco, G; Ripani, M; Ritchie, B G; Rosner, G; Rossi, P; Sabatié, F; Saini, M S; Salamanca, J; Salgado, C; Sandorfi, A; Santoro, J P; Sapunenko, V; Schott, D; Schumacher, R A; Serov, V S; Sharabian, Y G; Sharov, D; Shvedunov, N V; Smith, E S; Smith, L C; Sober, D I; Sokhan, D; Starostin, A; Stavinsky, A; Stepanyan, S; Stepanyan, S S; Stokes, B E; Stoler, P; Stopani, K A; Strakovsky, I I; Strauch, S; Taiuti, M; Tedeschi, D J; Teymurazyan, A; Tkabladze, A; Tkachenko, S; Todor, L; Tur, C; Ungaro, M; Vineyard, M F; Vlassov, A V; Watts, D P; Wei, X; Weinstein, L B; Weygand, D P; Williams, M; Wolin, E; Wood, M H; Yegneswaran, A; Yurov, M; Zana, L; Zhang, J; Zhao, B; Zhao, Z W

2009-03-13

We report on the results of the first measurement of exclusive f_{0}(980) meson photoproduction on protons for E_{gamma}=3.0-3.8 GeV and -t=0.4-1.0 GeV2. Data were collected with the CLAS detector at the Thomas Jefferson National Accelerator Facility. The resonance was detected via its decay in the pi;{+}pi;{-} channel by performing a partial wave analysis of the reaction gammap-->ppi;{+}pi;{-}. Clear evidence of the f_{0}(980) meson was found in the interference between P and S waves at M_{pi;{+}pi;{-}} approximately 1 GeV. The S-wave differential cross section integrated in the mass range of the f_{0}(980) was found to be a factor of about 50 smaller than the cross section for the rho meson. This is the first time the f_{0}(980) meson has been measured in a photoproduction experiment.

Measurement of Direct f0(980) Photoproduction on the Proton

NASA Astrophysics Data System (ADS)

Battaglieri, M.; de Vita, R.; Szczepaniak, A. P.; Adhikari, K. P.; Aghasyan, M.; Amaryan, M. J.; Ambrozewicz, P.; Anghinolfi, M.; Asryan, G.; Avakian, H.; Bagdasaryan, H.; Baillie, N.; Ball, J. P.; Baltzell, N. A.; Batourine, V.; Bedlinskiy, I.; Bellis, M.; Benmouna, N.; Berman, B. L.; Bibrzycki, L.; Biselli, A. S.; Bookwalter, C.; Bouchigny, S.; Boiarinov, S.; Bradford, R.; Branford, D.; Briscoe, W. J.; Brooks, W. K.; Bültmann, S.; Burkert, V. D.; Calarco, J. R.; Careccia, S. L.; Carman, D. S.; Casey, L.; Chen, S.; Cheng, L.; Clinton, E.; Cole, P. L.; Collins, P.; Crabb, D.; Crannell, H.; Crede, V.; Cummings, J. P.; Dale, D.; Daniel, A.; Dashyan, N.; de Masi, R.; de Sanctis, E.; Degtyarenko, P. V.; Deur, A.; Dhamija, S.; Dharmawardane, K. V.; Dickson, R.; Djalali, C.; Dodge, G. E.; Donnelly, J.; Doughty, D.; Dugger, M.; Dzyubak, O. P.; Egiyan, H.; Egiyan, K. S.; El Fassi, L.; Elouadrhiri, L.; Eugenio, P.; Fedotov, G.; Fersch, R.; Forest, T. A.; Fradi, A.; Gabrielyan, M. Y.; Gan, L.; Garçon, M.; Gasparian, A.; Gavalian, G.; Gevorgyan, N.; Gilfoyle, G. P.; Giovanetti, K. L.; Girod, F. X.; Glamazdin, O.; Goett, J.; Goetz, J. T.; Gohn, W.; Golovatch, E.; Gordon, C. I. O.; Gothe, R. W.; Graham, L.; Griffioen, K. A.; Guidal, M.; Guler, N.; Guo, L.; Gyurjyan, V.; Hadjidakis, C.; Hafidi, K.; Hakobyan, H.; Hakobyan, R. S.; Hanretty, C.; Hardie, J.; Hassall, N.; Heddle, D.; Hersman, F. W.; Hicks, K.; Hleiqawi, I.; Holtrop, M.; Hyde, C. E.; Ilieva, Y.; Ireland, D. G.; Ishkhanov, B. S.; Isupov, E. L.; Ito, M. M.; Jenkins, D.; Jo, H. S.; Johnstone, J. R.; Joo, K.; Juengst, H. G.; Kageya, T.; Kalantarians, N.; Keller, D.; Kellie, J. D.; Khandaker, M.; Khetarpal, P.; Kim, W.; Klein, A.; Klein, F. J.; Klimenko, A. V.; Konczykowski, P.; Kossov, M.; Krahn, Z.; Kramer, L. H.; Kubarovsky, V.; Kuhn, J.; Kuhn, S. E.; Kuleshov, S. V.; Kuznetsov, V.; Lachniet, J.; Laget, J. M.; Langheinrich, J.; Lawrence, D.; Lee, T.; Lesniak, L.; Li, Ji; Livingston, K.; Lowry, M.; Lu, H. Y.; MacCormick, M.; Malace, S.; Markov, N.; Mattione, P.; McCracken, M. E.; McKinnon, B.; Mecking, B. A.; Melone, J. J.; Mestayer, M. D.; Meyer, C. A.; Mibe, T.; Mikhailov, K.; Mineeva, T.; Minehart, R.; Mirazita, M.; Miskimen, R.; Mochalov, V.; Mokeev, V.; Moreno, B.; Moriya, K.; Morrow, S. A.; Moteabbed, M.; Munevar, E.; Mutchler, G. S.; Nadel-Turonski, P.; Nakagawa, I.; Nasseripour, R.; Niccolai, S.; Niculescu, G.; Niculescu, I.; Niczyporuk, B. B.; Niroula, M. R.; Niyazov, R. A.; Nozar, M.; Osipenko, M.; Ostrovidov, A. I.; Park, K.; Park, S.; Pasyuk, E.; Paris, M.; Paterson, C.; Pereira, S. Anefalos; Pierce, J.; Pivnyuk, N.; Pocanic, D.; Pogorelko, O.; Pozdniakov, S.; Price, J. W.; Prok, Y.; Protopopescu, D.; Raue, B. A.; Riccardi, G.; Ricco, G.; Ripani, M.; Ritchie, B. G.; Rosner, G.; Rossi, P.; Sabatié, F.; Saini, M. S.; Salamanca, J.; Salgado, C.; Sandorfi, A.; Santoro, J. P.; Sapunenko, V.; Schott, D.; Schumacher, R. A.; Serov, V. S.; Sharabian, Y. G.; Sharov, D.; Shvedunov, N. V.; Smith, E. S.; Smith, L. C.; Sober, D. I.; Sokhan, D.; Starostin, A.; Stavinsky, A.; Stepanyan, S.; Stepanyan, S. S.; Stokes, B. E.; Stoler, P.; Stopani, K. A.; Strakovsky, I. I.; Strauch, S.; Taiuti, M.; Tedeschi, D. J.; Teymurazyan, A.; Tkabladze, A.; Tkachenko, S.; Todor, L.; Tur, C.; Ungaro, M.; Vineyard, M. F.; Vlassov, A. V.; Watts, D. P.; Wei, X.; Weinstein, L. B.; Weygand, D. P.; Williams, M.; Wolin, E.; Wood, M. H.; Yegneswaran, A.; Yurov, M.; Zana, L.; Zhang, J.; Zhao, B.; Zhao, Z. W.

2009-03-01

We report on the results of the first measurement of exclusive f0(980) meson photoproduction on protons for Eγ=3.0-3.8GeV and -t=0.4-1.0GeV2. Data were collected with the CLAS detector at the Thomas Jefferson National Accelerator Facility. The resonance was detected via its decay in the π+π- channel by performing a partial wave analysis of the reaction γp→pπ+π-. Clear evidence of the f0(980) meson was found in the interference between P and S waves at Mπ+π-˜1GeV. The S-wave differential cross section integrated in the mass range of the f0(980) was found to be a factor of about 50 smaller than the cross section for the ρ meson. This is the first time the f0(980) meson has been measured in a photoproduction experiment.

Analysis of the signal for attachment of a glycophospholipid membrane anchor

PubMed Central

1989-01-01

The COOH terminus of decay accelerating factor (DAF) contains a signal that directs attachment of a glycophospholipid (GPI) membrane anchor. To define this signal we deleted portions of the DAF COOH terminus and expressed the mutant cDNAs it CV1 origin-deficient SV-40 cells. Our results show that the COOH-terminal hydrophobic domain (17 residues) is absolutely required for GPI anchor attachment. However, when fused to the COOH terminus of a secreted protein this hydrophobic domain is insufficient to direct attachment of a GPI anchor. Additional specific information located within the adjacent 20 residues appears to be necessary. We speculate that by analogy with signal sequences for membrane translocation, GPI anchor attachment requires both a COOH- terminal hydrophobic domain (the GPI signal) as well as a suitable cleavage/attachment site located NH2 terminal to the signal. PMID:2466848

The End Point Tagger physics program at A2@MAMI

NASA Astrophysics Data System (ADS)

Steffen, Oliver

2017-04-01

The A2-Collaboration uses a beam of real photons from the tagged photon facility at the electron accelerator MAMI in Mainz, Germany, to study photo-produced mesons. A new tagging device allows access to the higher photon beam energy range of 1.4 to 1.6 GeV. A large dataset containing more than 6 million η' and roughly 29 million ω decays has been obtained. Analyses are ongoing, including a study of the cusp effect and Dalitz plot in η' → ηπ0π0, giving insight to the ππ scattering length and the structure of the ηππ system, as well as the measurement of the electromagnetic transition form factor in η' → e+e-γ, a cross section measurement of γp → 3π0, and branching ratio analyses of η' → ωγ and ω → ηγ.

Identification of hot spots in the variola virus complement inhibitor (SPICE) for human complement regulation.

PubMed

Yadav, Viveka Nand; Pyaram, Kalyani; Mullick, Jayati; Sahu, Arvind

2008-04-01

Variola virus, the causative agent of smallpox, encodes a soluble complement regulator named SPICE. Previously, SPICE has been shown to be much more potent in inactivating human complement than the vaccinia virus complement control protein (VCP), although they differ only in 11 amino acid residues. In the present study, we have expressed SPICE, VCP, and mutants of VCP by substituting each or more of the 11 non-variant VCP residues with the corresponding residue of SPICE to identify hot spots that impart functional advantage to SPICE over VCP. Our data indicate that (i) SPICE is approximately 90-fold more potent than VCP in inactivating human C3b, and the residues Y98, Y103, K108 and K120 are predominantly responsible for its enhanced activity; (ii) SPICE is 5.4-fold more potent in inactivating human C4b, and residues Y98, Y103, K108, K120 and L193 mainly dictate this increase; (iii) the classical pathway decay-accelerating activity of activity is only twofold higher than that of VCP, and the 11 mutations in SPICE do not significantly affect this activity; (iv) SPICE possesses significantly greater binding ability to human C3b compared to VCP, although its binding to human C4b is lower than that of VCP; (v) residue N144 is largely responsible for the increased binding of SPICE to human C3b; and (vi) the human specificity of SPICE is dictated primarily by residues Y98, Y103, K108, and K120 since these are enough to formulate VCP as potent as SPICE. Together, these results suggest that principally 4 of the 11 residues that differ between SPICE and VCP partake in its enhanced function against human complement.

Identification of Hot Spots in the Variola Virus Complement Inhibitor (SPICE) for Human Complement Regulation▿

PubMed Central

Yadav, Viveka Nand; Pyaram, Kalyani; Mullick, Jayati; Sahu, Arvind

2008-01-01

Variola virus, the causative agent of smallpox, encodes a soluble complement regulator named SPICE. Previously, SPICE has been shown to be much more potent in inactivating human complement than the vaccinia virus complement control protein (VCP), although they differ only in 11 amino acid residues. In the present study, we have expressed SPICE, VCP, and mutants of VCP by substituting each or more of the 11 non-variant VCP residues with the corresponding residue of SPICE to identify hot spots that impart functional advantage to SPICE over VCP. Our data indicate that (i) SPICE is ∼90-fold more potent than VCP in inactivating human C3b, and the residues Y98, Y103, K108 and K120 are predominantly responsible for its enhanced activity; (ii) SPICE is 5.4-fold more potent in inactivating human C4b, and residues Y98, Y103, K108, K120 and L193 mainly dictate this increase; (iii) the classical pathway decay-accelerating activity of activity is only twofold higher than that of VCP, and the 11 mutations in SPICE do not significantly affect this activity; (iv) SPICE possesses significantly greater binding ability to human C3b compared to VCP, although its binding to human C4b is lower than that of VCP; (v) residue N144 is largely responsible for the increased binding of SPICE to human C3b; and (vi) the human specificity of SPICE is dictated primarily by residues Y98, Y103, K108, and K120 since these are enough to formulate VCP as potent as SPICE. Together, these results suggest that principally 4 of the 11 residues that differ between SPICE and VCP partake in its enhanced function against human complement. PMID:18216095

Elementary Particle Physics and High Energy Phenomena: Final Report for FY2010-13

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cumalat, John P.; de Alwis, Senarath P.; DeGrand, Thomas A.

2013-06-27

The work under this grant consists of experimental, theoretical, and phenomenological research on the fundamental properties of high energy subnuclear particles. The work is conducted at the University of Colorado, the European Organization for Nuclear Research (CERN), the Japan Proton Accelerator Research Complex (J-PARC), Fermi National Accelerator Laboratory (FNAL), SLAC National Accelerator Laboratory (SLAC), Los Alamos National Laboratory (LANL), and other facilities, employing neutrino-beam experiments, test beams of various particles, and proton-proton collider experiments. It emphasizes mass generation and symmetry-breaking, neutrino oscillations, bottom particle production and decay, detector development, supergravity, supersymmetry, superstrings, quantum chromodynamics, nonequilibrium statistical mechanics, cosmology, phase transitions,more » lattice gauge theory, and anomaly-free theories. The goals are to improve our understanding of the basic building blocks of matter and their interactions. Data from the Large Hadron Collider at CERN have revealed new interactions responsible for particle mass, and perhaps will lead to a more unified picture of the forces among elementary material constituents. To this end our research includes searches for manifestations of theories such as supersymmetry and new gauge bosons, as well as the production and decay of heavy-flavored quarks. Our current work at J-PARC, and future work at new facilities currently under conceptual design, investigate the specifics of how the neutrinos change flavor. The research is integrated with the training of students at all university levels, benefiting both the manpower and intellectual base for future technologies.« less

Improved description of the 2 ν β β -decay and a possibility to determine the effective axial-vector coupling constant

NASA Astrophysics Data System (ADS)

Šimkovic, Fedor; Dvornický, Rastislav; Štefánik, Dušan; Faessler, Amand

2018-03-01

An improved formalism of the two-neutrino double-beta decay (2 ν β β -decay) rate is presented, which takes into account the dependence of energy denominators on lepton energies via the Taylor expansion. Until now, only the leading term in this expansion has been considered. The revised 2 ν β β -decay rate and differential characteristics depend on additional phase-space factors weighted by the ratios of 2 ν β β -decay nuclear matrix elements with different powers of the energy denominator. For nuclei of experimental interest all phase-space factors are calculated by using exact Dirac wave functions with finite nuclear size and electron screening. For isotopes with measured 2 ν β β -decay half-life the involved nuclear matrix elements are determined within the quasiparticle random-phase approximation with partial isospin restoration. The importance of correction terms to the 2 ν β β -decay rate due to Taylor expansion is established and the modification of shape of single and summed electron energy distributions is discussed. It is found that the improved calculation of the 2 ν β β -decay predicts slightly suppressed 2 ν β β -decay background to the neutrinoless double-beta decay signal. Furthermore, an approach to determine the value of effective weak-coupling constant in nuclear medium gAeff is proposed.

Direct evidence of an elongation factor-Tu/Ts·GTP·Aminoacyl-tRNA quaternary complex.

PubMed

Burnett, Benjamin J; Altman, Roger B; Ferguson, Angelica; Wasserman, Michael R; Zhou, Zhou; Blanchard, Scott C

2014-08-22

During protein synthesis, elongation factor-Tu (EF-Tu) bound to GTP chaperones the entry of aminoacyl-tRNA (aa-tRNA) into actively translating ribosomes. In so doing, EF-Tu increases the rate and fidelity of the translation mechanism. Recent evidence suggests that EF-Ts, the guanosine nucleotide exchange factor for EF-Tu, directly accelerates both the formation and dissociation of the EF-Tu-GTP-Phe-tRNA(Phe) ternary complex (Burnett, B. J., Altman, R. B., Ferrao, R., Alejo, J. L., Kaur, N., Kanji, J., and Blanchard, S. C. (2013) J. Biol. Chem. 288, 13917-13928). A central feature of this model is the existence of a quaternary complex of EF-Tu/Ts·GTP·aa-tRNA(aa). Here, through comparative investigations of phenylalanyl, methionyl, and arginyl ternary complexes, and the development of a strategy to monitor their formation and decay using fluorescence resonance energy transfer, we reveal the generality of this newly described EF-Ts function and the first direct evidence of the transient quaternary complex species. These findings suggest that EF-Ts may regulate ternary complex abundance in the cell through mechanisms that are distinct from its guanosine nucleotide exchange factor functions. © 2014 by The American Society for Biochemistry and Molecular Biology, Inc.

Optical force and torque on a dielectric Rayleigh particle by a circular Airy vortex beam

NASA Astrophysics Data System (ADS)

Chen, Musheng; Huang, Sujuan; Shao, Wei; Liu, Xianpeng

2018-03-01

Optical force and torque exerted on the Rayleigh particles by tightly focused circularly polarized circular Airy vortex beams (CAVB) in the far field are studied in this paper. The relation between parameters of circularly polarized CAVB and the trapping properties is numerically analyzed based on Rayleigh models and the Debye diffraction theory. The results show that both the high refractive index and low refractive index particles can be fully stably trapped in three dimensions by circularly polarized CAVB. The parameters of circularly polarized CAVB greatly affect the optical force. The longitudinal and transverse gradient force increase with the increase of decay factor and scaling factor, and decrease with the increase of the radius of the first primary ring and topological charges. The positions of the longitudinal stable equilibrium move toward the high numerical aperture lens when the scaling factor and the radius of the primary ring increase. The trapping range is broadened with the decrease of scaling factor. The optical orbital torque (OOT) of circularly polarized CAVB has circular symmetry and remains positive or negative. With the increase of topological charges, the peak value of OOT first increases and then decreases after reaches a maximum. These results are useful for optical trapping, optical levitation and particle acceleration.

Electromagnetic Transition Form Factor of the η meson with WASA-at-COSY

NASA Astrophysics Data System (ADS)

Goswami, A.

2016-11-01

In this work we present a study of the Dalitz decay η → γe+e-. The aim of this work is to measure the transition form factor of the η meson. The transition form factor of the η meson describes the electromagnetic structure of the meson. The study of the Dalitz decay helps to calculate the transition form factor of the η meson. When a particle is point-like it's decay rate can be calculated within QED. However, the complex structure of the meson modifies its decay rate. The transition form factor is determined by comparing the lepton-antilepton invariant mass distribution with QED. For this study data on proton-proton reaction at a beam energy of 1.4 GeV has been collected with WASA-at-COSY detector at Forschungszentrum Juelich, Germany. In the higher invariant mass region recent theoretical calculations slightly deviate from the fit to the data. We expect better results in the higher invariant mass region than previous measurements. The preliminary results of the analysis will be presented.

Obesity- and aging-induced excess of central transforming growth factor-β potentiates diabetic development via an RNA stress response

PubMed Central

Yan, Jingqi; Zhang, Hai; Yin, Ye; Li, Juxue; Tang, Yizhe; Purkayastha, Sudarshana; Li, Lianxi; Cai, Dongsheng

2014-01-01

The brain, in particular the hypothalamus, plays a role in regulating glucose homeostasis; however, it remains unclear if the brain is causally involved in diabetic development. Here, we identified that hypothalamic TGF-β is excessive under conditions of not only obesity but aging, which are two general etiological factors of diabetes. Pharmacological and genetic approaches consistently revealed that brain TGF-β excess caused hyperglycemia and glucose intolerance in a body weight-independent manner. Cell-specific genetic models demonstrated that astrocytes are responsible for brain TGF-β excess, and POMC neurons are crucial for the pro-diabetic effect of TGF-β excess. Mechanistically, TGF-β excess induced hypothalamic RNA stress response to accelerate IκBα mRNA decay, leading to an atypical, mRNA metabolism-driven hypothalamic NF-κB activation which links obesity as well as aging to hypothalamic inflammation. In conclusion, brain TGF-β excess and induction of RNA stress response and hypothalamic inflammation are important for the pro-diabetic effects of obesity or aging. PMID:25086906

Virulence and biodegradation potential of dynamic microbial communities associated with decaying Cladophora in Great Lakes

USGS Publications Warehouse

Chun, Chan Lan; Peller, Julie R.; Shively, Dawn; Byappanahalli, Muruleedhara N.; Whitman, Richard L.; Staley, Christopher; Zhang, Qian; Ishii, Satoshi; Sadowsky, Michael J.

2017-01-01

Cladophora mats that accumulate and decompose along shorelines of the Great Lakes create potential threats to the health of humans and wildlife. The decaying algae create a low oxygen and redox potential environment favoring growth and persistence of anaerobic microbial populations, including Clostridium botulinum, the causal agent of botulism in humans, birds, and other wildlife. In addition to the diverse population of microbes, a dynamic chemical environment is generated, which involves production of numerous organic and inorganic substances, many of which are believed to be toxic to the sand and aquatic biotic communities. In this study, we used 16S-rDNA-based-amplicon sequencing and microfluidic-based quantitative PCR approaches to characterize the bacterial community structure and the abundances of human pathogens associated with Cladophora at different stages (up to 90 days) of algal decay in laboratory microcosms. Oxygen levels were largely depleted after a few hours of incubation. As Cladophora decayed, the algal microbial biodiversity decreased within 24 h, and the mat transitioned from an aerobic to anaerobic environment. There were increasing abundances of enteric and pathogenic bacteria during decomposition of Cladophora, including Acinetobacter, Enterobacter, Kluyvera, Cedecea, and others. In contrast, there were no or very few sequences (< 0.07%) assigned to such groups in fresh Cladophora samples. Principal coordinate analysis indicated that the bacterial community structure was dynamic and changed significantly with decay time. Knowledge of microbial communities and chemical composition of decaying algal mats is critical to our further understanding of the role that Cladophora plays in a beach ecosystem's structure and function, including the algal role in trophic interactions. Based on these findings, public and environmental health concerns should be considered when decaying Cladophora mats accumulate Great Lakes shorelines.

Virulence and biodegradation potential of dynamic microbial communities associated with decaying Cladophora in Great Lakes.

PubMed

Chun, Chan Lan; Peller, Julie R; Shively, Dawn; Byappanahalli, Muruleedhara N; Whitman, Richard L; Staley, Christopher; Zhang, Qian; Ishii, Satoshi; Sadowsky, Michael J

2017-01-01

Cladophora mats that accumulate and decompose along shorelines of the Great Lakes create potential threats to the health of humans and wildlife. The decaying algae create a low oxygen and redox potential environment favoring growth and persistence of anaerobic microbial populations, including Clostridium botulinum, the causal agent of botulism in humans, birds, and other wildlife. In addition to the diverse population of microbes, a dynamic chemical environment is generated, which involves production of numerous organic and inorganic substances, many of which are believed to be toxic to the sand and aquatic biotic communities. In this study, we used 16S-rDNA-based-amplicon sequencing and microfluidic-based quantitative PCR approaches to characterize the bacterial community structure and the abundances of human pathogens associated with Cladophora at different stages (up to 90days) of algal decay in laboratory microcosms. Oxygen levels were largely depleted after a few hours of incubation. As Cladophora decayed, the algal microbial biodiversity decreased within 24h, and the mat transitioned from an aerobic to anaerobic environment. There were increasing abundances of enteric and pathogenic bacteria during decomposition of Cladophora, including Acinetobacter, Enterobacter, Kluyvera, Cedecea, and others. In contrast, there were no or very few sequences (<0.07%) assigned to such groups in fresh Cladophora samples. Principal coordinate analysis indicated that the bacterial community structure was dynamic and changed significantly with decay time. Knowledge of microbial communities and chemical composition of decaying algal mats is critical to our further understanding of the role that Cladophora plays in a beach ecosystem's structure and function, including the algal role in trophic interactions. Based on these findings, public and environmental health concerns should be considered when decaying Cladophora mats accumulate Great Lakes shorelines. Copyright © 2016 Elsevier B.V. All rights reserved.

[Litter decomposition and its main affecting factors in tidal marshes of Minjiang River Estuary, East China].

PubMed

Zhang, Lin-Hai; Zeng, Cong-Sheng; Zhang, Wen-Juan; Wang, Tian-E; Tong, Chuan

2012-09-01

By using litterbag method, this paper studied the decomposition of the leaf- and flower litters of two emergent macrophytes, native species Phragmites australis and invasive species Spartina alterniflora, and related affecting factors in the Minjiang River estuary of East China. In the decomposition process of the litters, the decay of standing litter (0-90 days) was an important period, and the loss rate of the flower- and leaf litters dry mass of P. australis and S. alterniflora was 15.0 +/- 3.5% and 13.3 +/- 1.1%, and 31.9 +/- 1.1% and 20.8 +/- 1.4%, respectively. During lodging decay period (91-210 days), the loss rate of the flower- and leaf litters dry mass of P. australis and S. alterniflora was 69.5 +/- 0.6% and 71.5 +/- 2.5%, and 76.8 +/- 1.9% and 67.5 +/- 2.1%, respectively. In standing decay period, the decomposition rate of the two plants litters was positively correlated with the litters C/N but negatively correlated to the litters N/P, and the litters P was an important factor limiting the litters decay. In lodging decay period, the effects of the litters C/N, C/P, and N/P decreased, while the environment factors (climate, soil moisture, soil acidity and salinity, and sediment properties) acted more important roles. The differences in the factors affecting the decay of the litters in different decomposition periods were mainly related to the micro-environment and tidal process for the two plant communities.

Coupled effects of chemotaxis and growth on traveling bacterial waves.

PubMed

Yan, Zhifeng; Bouwer, Edward J; Hilpert, Markus

2014-08-01

Traveling bacterial waves are capable of improving contaminant remediation in the subsurface. It is fairly well understood how bacterial chemotaxis and growth separately affect the formation and propagation of such waves. However, their interaction is not well understood. We therefore perform a modeling study to investigate the coupled effects of chemotaxis and growth on bacterial migration, and examine their effects on contaminant remediation. We study the waves by using different initial electron acceptor concentrations for different bacteria and substrate systems. Three types of traveling waves can occur: a chemotactic wave due to the biased movement of chemotactic bacteria resulting from metabolism-generated substrate concentration gradients; a growth/decay/motility wave due to a dynamic equilibrium between bacterial growth, decay and random motility; and an integrated wave due to the interaction between bacterial chemotaxis and growth. Chemotaxis hardly enhances the bacterial propagation if it is too weak to form a chemotactic wave or its wave speed is less than half of the growth/decay/motility wave speed. However, chemotaxis significantly accelerates bacterial propagation once its wave speed exceeds the growth/decay/motility wave speed. When convection occurs, it speeds up the growth/decay/motility wave but slows down or even eliminates the chemotactic wave due to the dispersion. Bacterial survival proves particularly important for bacterial propagation. Therefore we develop a conceptual model to estimate the speed of growth/decay/motility waves. Copyright © 2014 Elsevier B.V. All rights reserved.

Factors affecting perception thresholds of vertical whole-body vibration in recumbent subjects: Gender and age of subjects, and vibration duration

NASA Astrophysics Data System (ADS)

Matsumoto, Y.; Maeda, S.; Iwane, Y.; Iwata, Y.

2011-04-01

Some factors that may affect human perception thresholds of the vertical whole-body vibrations were investigated in two laboratory experiments with recumbent subjects. In the first experiment, the effects of gender and age of subjects on perception were investigated with three groups of 12 subjects, i.e., young males, young females and old males. For continuous sinusoidal vibrations at 2, 4, 8, 16, 31.5 and 63 Hz, there were no significant differences in the perception thresholds between male and female subjects, while the thresholds of young subjects tended to be significantly lower than the thresholds of old subjects. In the second experiment, the effect of vibration duration was investigated by using sinusoidal vibrations, at the same frequencies as above, modulated by the Hanning windows with different lengths (i.e., 0.5, 1.0, 2.0 and 4.0 s) for 12 subjects. It was found that the peak acceleration at the threshold tended to decrease with increasing duration of vibration. The perception thresholds were also evaluated by the running root-mean-square (rms) acceleration and the fourth power acceleration method defined in the current standards. The differences in the threshold of the transient vibrations for different durations were less with the fourth power acceleration method. Additionally, the effect of the integration time on the threshold was investigated for the running rms acceleration and the fourth power acceleration. It was found that the integration time that yielded less differences in the threshold of vibrations for different durations depended on the frequency of vibration.

Glucocorticoid receptor interacts with PNRC2 in a ligand-dependent manner to recruit UPF1 for rapid mRNA degradation.

PubMed

Cho, Hana; Park, Ok Hyun; Park, Joori; Ryu, Incheol; Kim, Jeonghan; Ko, Jesang; Kim, Yoon Ki

2015-03-31

Glucocorticoid receptor (GR), which was originally known to function as a nuclear receptor, plays a role in rapid mRNA degradation by acting as an RNA-binding protein. The mechanism by which this process occurs remains unknown. Here, we demonstrate that GR, preloaded onto the 5'UTR of a target mRNA, recruits UPF1 through proline-rich nuclear receptor coregulatory protein 2 (PNRC2) in a ligand-dependent manner, so as to elicit rapid mRNA degradation. We call this process GR-mediated mRNA decay (GMD). Although GMD, nonsense-mediated mRNA decay (NMD), and staufen-mediated mRNA decay (SMD) share upstream frameshift 1 (UPF1) and PNRC2, we find that GMD is mechanistically distinct from NMD and SMD. We also identify de novo cellular GMD substrates using microarray analysis. Intriguingly, GMD functions in the chemotaxis of human monocytes by targeting chemokine (C-C motif) ligand 2 (CCL2) mRNA. Thus, our data provide molecular evidence of a posttranscriptional role of the well-studied nuclear hormone receptor, GR, which is traditionally considered a transcription factor.

CHLORINE DECAY AND BIOFILM STUDIES IN A PILOT SCALE DRINKING WATER DISTRIBUTION DEAD END PIPE SYSTEM

EPA Science Inventory

Chlorine decay experiments using a pilot-scale water distribution dead end pipe system were conducted to define relationships between chlorine decay and environmental factors. These included flow rate, biomass concentration and biofilm density, and initial chlorine concentrations...

DOE Office of Scientific and Technical Information (OSTI.GOV)

Klein, Steven Karl; Determan, John C.

Dynamic System Simulation (DSS) models of fissile solution systems have been developed and verified against a variety of historical configurations. DSS techniques have been applied specifically to subcritical accelerator-driven systems using fissile solution fuels of uranium. Initial DSS models were developed in DESIRE, a specialized simulation scripting language. In order to tailor the DSS models to specifically meet needs of system designers they were converted to a Visual Studio implementation, and one of these subsequently to National Instrument’s LabVIEW for human factors engineering and operator training. Specific operational characteristics of subcritical accelerator-driven systems have been examined using a DSS modelmore » tailored to this particular class using fissile fuel.« less

A Geomorphologically Driven Conditional Assessment for the Study of Urban Stone Decay

NASA Astrophysics Data System (ADS)

Johnston, Brian; McKinley, Jennifer; Warke, Patricia; Ruffell, Alastair

2017-04-01

Much of humanity's legacy is within the built environment and therefore in the stones that have been used for its construction. This means that targeted building conservation strategies are vital when considering the maintenance of this heritage. Conditional assessments play a major part in these efforts by classifying blocks based upon their visual state of decay. However, as these tools were developed with the purpose of informing decision making by professionals in the construction and conservation industries, limitations exist when considering them as part of studies with a geomorphological focus. Links between the decay of stonework and spatially variable control factors, such as material properties, microclimatic conditions and pollutant distribution, have been well documented in past studies, with observations of decay on wall sections supporting this concept. For example, the distribution of weathering features can indicate that certain blocks are more susceptible than others to decay. Additionally, adjoining blocks can exhibit similar processes, suggestive of interaction between the blocks, indicating a linkage between individual block scale decay and processes acting at a wider wall scale. These observations have led to comparisons between the weathering of rock outcrops and building façades, with mortar joints playing the role of fractures or bedding. This comparison has highlighted the necessity to not simply consider decay in terms of architecture or engineering, but also in terms of the geomorphological processes taking place. The patterns of decay created at a wall scale, whilst being visually chaotic, can provide clues to the controlling factors acting upon this system, if they are subjected to informed scrutiny. Despite such discussions, the focus of surveys towards remediation have created limitations when applying the results of these surveys towards the understanding of processes acting between blocks at a wall scale. This work aims to take into consideration these limitations by undertaking two conditional assessments, using differing techniques, of wall sections at Fitzroy Presbyterian Church in Belfast. These assessments will be undertaken using a classification system focusing upon percentage of surface alteration. Initially, an assessment was carried out focussing on classifying each block individually. This was then followed by observations in a regular grid of 10x10cm squares across the wall sections. Results suggest that decay features develop beyond the extents of a single stone when situated within a larger built structure, with mortar and blocks providing both interconnectivity and barriers that influence the spread of decay. The results suggest the presence of three wall scale processes; urban microclimatic influencing capillary rise of ground water, architectural features creating a barrier and the passage of moisture through deteriorating mortar. Probe permeametry, GPR and 3D modelling of the wall sections were used to provide support for these findings. For the conservationist, application of a gridded observation approach is time consuming and of little use when deciding upon the remediation of individual blocks. However, in geomorphologically focused studies it facilitates a greater understanding of processes that extend beyond a single block, particularly when considering sites where the development of decay appears to be spatially complex.

Free Radicals Accelerate the Decay of Long-Term Potentiation in Field CA1 of Guinea-Pig Hippocampus

DTIC Science & Technology

1991-01-01

Andersen P. Sundberg S II . Sveen 0. Swann J W and Wigstrom II ( 1980 ) Possible mechanisms for long-lasting potentiation of synaptic transmission in...concentratin of gunea ptg heart Cardiotux Res. 23. 767-773 15 Hyslop P. A,* Hinshawv D B , Schrnufttatter 1,. . Sklar L A, Spragg R G soid Cochrane C G3

Comprehensive overview of FPL field testing conducted in the tropics (1945-2005)

Treesearch

Grant T. Kirker; Stan L. Lebow; Mark E. Mankowski

2016-01-01

Tropical exposure often represents a more severe environment for treated wood and wood based products. Accelerated tropical decay rates are typically attributed to higher mean rainfall and temperatures. The Forest Products Laboratory (FPL) in Madison, WI has been conducting tropical field tests in a variety of locations since the early 1940’s. This paper summarizes FPL...

Boosting the Light: X-ray Physics in Confinement

ScienceCinema

Rhisberger, Ralf [HASYLAB/ DESY

2017-12-09

Remarkable effects are observed if light is confined to dimensions comparable to the wavelength of the light. The lifetime of atomic resonances excited by the radiation is strongly reduced in photonic traps, such as cavities or waveguides. Moreover, one observes an anomalous boost of the intensity scattered from the resonant atoms. These phenomena results from the strong enhancement of the photonic density of states in such geometries. Many of these effects are currently being explored in the regime of vsible light due to their relevance for optical information processing. It is thus appealing to study these phenomena also for much shorter wavelengths. This talk illuminates recent experiments where synchrotron x-rays were trapped in planar waveguides to resonantly excite atomos ([57]Fe nuclei_ embedded in them. In fact, one observes that the radiative decay of these excited atoms is strongly accelerated. The temporal acceleration of the decay goes along with a strong boost of the radiation coherently scattered from the confined atmos. This can be exploited to obtain a high signal-to-noise ratio from tiny quantities of material, leading to manifold applications in the investigation of nanostructured materials. One application is the use of ultrathin probe layers to image the internal structure of magnetic layer systems.

A possible origin of gamma rays from the Fermi Bubbles

NASA Astrophysics Data System (ADS)

Thoudam, Satyendra

2014-11-01

One of the most exciting discoveries of recent years is a pair of gigantic gamma-ray emission regions, the so-called Fermi bubbles, above and below the Galactic center. The bubbles, discovered by the Fermi space telescope, extend up to ∼50° in Galactic latitude and are ∼40° wide in Galactic longitude. The gamma-ray emission is also found to correlate with radio, microwave and X-rays emission. The origin of the bubbles and the associated non-thermal emissions are still not clearly understood. Possible explanations for the non-thermal emission include cosmic-ray injection from the Galactic center by high speed Galactic winds/jets, acceleration by multiple shocks or plasma turbulence present inside the bubbles, and acceleration by strong shock waves associated with the expansion of the bubbles. In this paper, I will discuss the possibility that the gamma-ray emission is produced by the injection of Galactic cosmic-rays mainly protons during their diffusive propagation through the Galaxy. The protons interact with the bubble plasma producing π°-decay gamma rays, while at the same time, radio and microwave synchrotron emissions are produced by the secondary electrons/positrons resulting from the π± decays.

Possibilities For The LAGUNA Projects At The Fréjus Site

NASA Astrophysics Data System (ADS)

Mosca, Luigi

2010-11-01

The present laboratory (LSM) at the Fréjus site and the project of a first extension of it, mainly aimed at the next generation of dark matter and double beta decay experiments, are briefly reviewed. Then the main characteristics of the LAGUNA cooperation and Design Study network are summarized. Seven underground sites in Europe are considered in LAGUNA and are under study as candidates for the installation of Megaton scale detectors using three different techniques: a liquid Argon TPC (GLACIER), a liquid scintillator detector (LENA) and a Water Cerenkov (MEMPHYS), all mainly aimed at investigation of proton decay and properties of neutrinos from SuperNovae and other astrophysical sources as well as from accelerators (Super-beams and/or Beta-beams from CERN). One of the seven sites is located at Fréjus, near the present LSM laboratory, and the results of its feasibility study are presented and discussed. Then the physics potential of a MEMPHYS detector installed in this site are emphasized both for non-accelerator and for neutrino beam based configurations. The MEMPHYNO prototype with its R&D programme is presented. Finally a possible schedule is sketched.

Hadronic model for the non-thermal radiation from the binary system AR Scorpii

NASA Astrophysics Data System (ADS)

Bednarek, W.

2018-05-01

AR Scorpii is a close binary system containing a rotation powered white dwarf and a low-mass M type companion star. This system shows non-thermal emission extending up to the X-ray energy range. We consider hybrid (lepto-hadronic) and pure hadronic models for the high energy non-thermal processes in this binary system. Relativistic electrons and hadrons are assumed to be accelerated in a strongly magnetised, turbulent region formed in collision of a rotating white dwarf magnetosphere and a magnetosphere/dense atmosphere of the M-dwarf star. We propose that the non-thermal X-ray emission is produced either by the primary electrons or the secondary e± pairs from decay of charged pions created in collisions of hadrons with the companion star atmosphere. We show that the accompanying γ-ray emission from decay of neutral pions, which are produced by these same protons, is expected to be on the detectability level of the present and/or the future satellite and Cherenkov telescopes. The γ-ray observations of the binary system AR Sco should allow us to constrain the efficiency of hadron and electron acceleration and also the details of the radiation processes.

Precise measurement of energy of the first excited state of 115Sn (Eexc ≃ 497.3 keV)

NASA Astrophysics Data System (ADS)

Zheltonozhsky, V. A.; Savrasov, A. M.; Strilchuk, N. V.; Tretyak, V. I.

2018-01-01

Single beta decay of 115In to the first excited level of 115Sn (E\\text{exc}≃ 497.3 \\text{keV} ) is known as β-decay with the lowest Qβ value. To determine the Qβ precisely, one has to measure very accurately the E\\text{exc} value. A sample of tin enriched in 115Sn to 50.7% was irradiated by a proton beam at the U-120 accelerator of INR, Kyiv. The 115Sb radioactive isotope, created in the 115Sn(p,n)115Sb reaction, decays with T1/2 = 32 \\text{min} to 115Sn populating the 497 keV level with ≃ 96{%} probability. The total statistics of ˜105 counts collected in the 497 keV peak in a series of measurements, the exact description of the peak shape and the precisely known calibration points around the 497 keV peak allowed to obtain the value E\\text{exc}= 497.342(3) \\text{keV} , which is the most precise to-date. This leads to the following Qβ\\ast value for the decay 115In → 115Sn*: Qβ\\ast= 147 +/- 10 \\text{eV} .

Quasi-two-body decays B → Kρ → Kππ in perturbative QCD approach

NASA Astrophysics Data System (ADS)

Wang, Wen-Fei; Li, Hsiang-nan

2016-12-01

We analyze the quasi-two-body decays B → Kρ → Kππ in the perturbative QCD (PQCD) approach, in which final-state interactions between the pions in the resonant regions associated with the P-wave states ρ (770) and ρ‧ (1450) are factorized into two-pion distribution amplitudes. Adopting experimental inputs for the time-like pion form factors involved in two-pion distribution amplitudes, we calculate branching ratios and direct CP asymmetries of the B → Kρ (770) , Kρ‧ (1450) → Kππ modes. It is shown that agreement of theoretical results with data can be achieved, through which Gegenbauer moments of the P-wave two-pion distribution amplitudes are determined. The consistency between the three-body and two-body analyses of the B → Kρ (770) → Kππ decays supports the PQCD factorization framework for exclusive hadronic B meson decays.

Measurement of CP observables in B{sup {+-}{yields}D}{sub CP}K{sup {+-}}decays and constraints on the CKM angle {gamma}

DOE Office of Scientific and Technical Information (OSTI.GOV)

Amo Sanchez, P. del; Lees, J. P.; Poireau, V.

Using the entire sample of 467x10{sup 6} {Upsilon}(4S){yields}BB decays collected with the BABAR detector at the PEP-II asymmetric-energy B factory at the SLAC National Accelerator Laboratory, we perform an analysis of B{sup {+-}}{yields}DK{sup {+-}}decays, using decay modes in which the neutral D meson decays to either CP-eigenstates or non-CP-eigenstates. We measure the partial decay rate charge asymmetries for CP-even and CP-odd D final states to be A{sub CP+}=0.25{+-}0.06{+-}0.02 and A{sub CP-}=-0.09{+-}0.07{+-}0.02, respectively, where the first error is the statistical and the second is the systematic uncertainty. The parameter A{sub CP+} is different from zero with a significance of 3.6 standardmore » deviations, constituting evidence for direct CP violation. We also measure the ratios of the charged-averaged B partial decay rates in CP and non-CP decays, R{sub CP+}=1.18{+-}0.09{+-}0.05 and R{sub CP-}=1.07{+-}0.08{+-}0.04. We infer frequentist confidence intervals for the angle {gamma} of the unitarity triangle, for the strong phase difference {delta}{sub B}, and for the amplitude ratio r{sub B}, which are related to the B{sup -}{yields}DK{sup -} decay amplitude by r{sub B}e{sup i({delta}{sub B}-{gamma})}=A(B{sup -}{yields}D{sup 0}K{sup -})/A(B{sup -}{yields}D{sup 0}K{sup -}). Including statistical and systematic uncertainties, we obtain 0.24

96-Channel receive-only head coil for 3 Tesla: design optimization and evaluation.

PubMed

Wiggins, Graham C; Polimeni, Jonathan R; Potthast, Andreas; Schmitt, Melanie; Alagappan, Vijay; Wald, Lawrence L

2009-09-01

The benefits and challenges of highly parallel array coils for head imaging were investigated through the development of a 3T receive-only phased-array head coil with 96 receive elements constructed on a close-fitting helmet-shaped former. We evaluated several designs for the coil elements and matching circuitry, with particular attention to sources of signal-to-noise ratio (SNR) loss, including various sources of coil loading and coupling between the array elements. The SNR and noise amplification (g-factor) in accelerated imaging were quantitatively evaluated in phantom and human imaging and compared to a 32-channel array built on an identical helmet-shaped former and to a larger commercial 12-channel head coil. The 96-channel coil provided substantial SNR gains in the distal cortex compared to the 12- and 32-channel coils. The central SNR for the 96-channel coil was similar to the 32-channel coil for optimum SNR combination and 20% lower for root-sum-of-squares combination. There was a significant reduction in the maximum g-factor for 96 channels compared to 32; for example, the 96-channel maximum g-factor was 65% of the 32-channel value for acceleration rate 4. The performance of the array is demonstrated in highly accelerated brain images.

A Measurement of the Lifetime of the Λ b Baryon with the CDF Detector at the Tevatron Run II

DOE Office of Scientific and Technical Information (OSTI.GOV)

Unverhau, Tatjana Alberta Hanna

2004-12-01

In March 2001 the Tevatron accelerator entered its Run II phase, providing colliding proton and anti-proton beams with an unprecedented center-of-mass energy of 1.96 TeV. The Tevatron is currently the only accelerator to produce Λ b baryons, which provides a unique opportunity to measure the properties of these particles. This thesis presents a measurement of the mean lifetime of the Λ b baryon in the semileptonic channel Λmore » $$0\\atop{b}$$ → Λ$$+\\atop{c}$$ μ - $$\\bar{v}$$ μ. In total 186 pb -1 of data were used for this analysis, collected with the CDF detector between February 2002 and September 2003. To select the long-lived events from b-decays, the secondary vertex trigger was utilized. This significant addition to the trigger for Run II allows, for the first time, the selection of events with tracks displaced from the primary interaction vertex at the second trigger level. After the application of selection cuts this trigger sample contains approximately 991 Λ b candidates. To extract the mean lifetime of Λ b baryons from this sample, they transverse decay length of the candidates is fitted with an unbinned maximum likelihood fit under the consideration of the missing neutrino momentum and the bias introduced by the secondary vertex trigger. The mean lifetime of the Λ b is measured to be τ = 1.29 ± 0.11(stat.) ± 0.07(syst.) ps equivalent to a mean decay length of cτ = 387 ± 33(stat.) ± 21 (syst.) μm.« less

An Evolutionary Genomic Approach to Identify Genes Involved in Human Birth Timing

PubMed Central

Orabona, Guilherme; Morgan, Thomas; Haataja, Ritva; Hallman, Mikko; Puttonen, Hilkka; Menon, Ramkumar; Kuczynski, Edward; Norwitz, Errol; Snegovskikh, Victoria; Palotie, Aarno; Fellman, Vineta; DeFranco, Emily A.; Chaudhari, Bimal P.; McGregor, Tracy L.; McElroy, Jude J.; Oetjens, Matthew T.; Teramo, Kari; Borecki, Ingrid; Fay, Justin; Muglia, Louis

2011-01-01

Coordination of fetal maturation with birth timing is essential for mammalian reproduction. In humans, preterm birth is a disorder of profound global health significance. The signals initiating parturition in humans have remained elusive, due to divergence in physiological mechanisms between humans and model organisms typically studied. Because of relatively large human head size and narrow birth canal cross-sectional area compared to other primates, we hypothesized that genes involved in parturition would display accelerated evolution along the human and/or higher primate phylogenetic lineages to decrease the length of gestation and promote delivery of a smaller fetus that transits the birth canal more readily. Further, we tested whether current variation in such accelerated genes contributes to preterm birth risk. Evidence from allometric scaling of gestational age suggests human gestation has been shortened relative to other primates. Consistent with our hypothesis, many genes involved in reproduction show human acceleration in their coding or adjacent noncoding regions. We screened >8,400 SNPs in 150 human accelerated genes in 165 Finnish preterm and 163 control mothers for association with preterm birth. In this cohort, the most significant association was in FSHR, and 8 of the 10 most significant SNPs were in this gene. Further evidence for association of a linkage disequilibrium block of SNPs in FSHR, rs11686474, rs11680730, rs12473870, and rs1247381 was found in African Americans. By considering human acceleration, we identified a novel gene that may be associated with preterm birth, FSHR. We anticipate other human accelerated genes will similarly be associated with preterm birth risk and elucidate essential pathways for human parturition. PMID:21533219

Many human accelerated regions are developmental enhancers

PubMed Central

Capra, John A.; Erwin, Genevieve D.; McKinsey, Gabriel; Rubenstein, John L. R.; Pollard, Katherine S.

2013-01-01

The genetic changes underlying the dramatic differences in form and function between humans and other primates are largely unknown, although it is clear that gene regulatory changes play an important role. To identify regulatory sequences with potentially human-specific functions, we and others used comparative genomics to find non-coding regions conserved across mammals that have acquired many sequence changes in humans since divergence from chimpanzees. These regions are good candidates for performing human-specific regulatory functions. Here, we analysed the DNA sequence, evolutionary history, histone modifications, chromatin state and transcription factor (TF) binding sites of a combined set of 2649 non-coding human accelerated regions (ncHARs) and predicted that at least 30% of them function as developmental enhancers. We prioritized the predicted ncHAR enhancers using analysis of TF binding site gain and loss, along with the functional annotations and expression patterns of nearby genes. We then tested both the human and chimpanzee sequence for 29 ncHARs in transgenic mice, and found 24 novel developmental enhancers active in both species, 17 of which had very consistent patterns of activity in specific embryonic tissues. Of these ncHAR enhancers, five drove expression patterns suggestive of different activity for the human and chimpanzee sequence at embryonic day 11.5. The changes to human non-coding DNA in these ncHAR enhancers may modify the complex patterns of gene expression necessary for proper development in a human-specific manner and are thus promising candidates for understanding the genetic basis of human-specific biology. PMID:24218637

Quasi-two-body decays Bc → D(s)[ρ(770),ρ(1450),ρ(1700)→]ππ in the perturbative QCD factorization approach

NASA Astrophysics Data System (ADS)

Ma, Ai-Jun; Li, Ya; Xiao, Zhen-Jun

2018-01-01

In this paper, we studied the quasi-two-body Bc →D(s) [ ρ (770) , ρ (1450) , ρ (1700) → ] ππ decays by employing the perturbative QCD (PQCD) factorization approach. The two-pion distribution amplitudes Φππ are applied to include the final-state interactions between the pion pair, while the time-like form factors Fπ (w2) associated with the P-wave resonant states ρ (770), ρ (1450) and ρ (1700) are extracted from the experimental data of the e+e- annihilation. We found that: (a) the PQCD predictions for the branching ratios of the quasi-two-body Bc →D(s) [ ρ (770) , ρ (1450) , ρ (1700) → ] ππ decays are in the order of 10-9 to 10-5 and the direct CP violations around (10 - 40)% in magnitude; (b) the two sets of the large hierarchy R 1 a , 1 b , 1 c and R 2 a , 2 b , 2 c for the ratios of the branching ratios of the considered decays are defined and can be understood in the PQCD factorization approach, while the self-consistency between the quasi-two-body and two-body framework for Bc →D(s) [ ρ (770) → ] ππ and Bc →D(s) ρ (770) decays are confirmed by our numerical results; (c) taking currently known B (ρ (1450) → ππ) and B (ρ (1700) → ππ) as input, we extracted the theoretical predictions for B (Bc → Dρ (1450)) and B (Bc → Dρ (1700)) from the PQCD predictions for the decay rates of the quasi-two-body decays Bc → D [ ρ (1450) , ρ (1700) → ] ππ. All the PQCD predictions will be tested in the future experiments.

Relativistic corrections to the form factors of Bc into P-wave orbitally excited charmonium

NASA Astrophysics Data System (ADS)

Zhu, Ruilin

2018-06-01

We investigated the form factors of the Bc meson into P-wave orbitally excited charmonium using the nonrelativistic QCD effective theory. Through the analytic computation, the next-to-leading order relativistic corrections to the form factors were obtained, and the asymptotic expressions were studied in the infinite bottom quark mass limit. Employing the general form factors, we discussed the exclusive decays of the Bc meson into P-wave orbitally excited charmonium and a light meson. We found that the relativistic corrections lead to a large correction for the form factors, which makes the branching ratios of the decay channels B (Bc ± →χcJ (hc) +π± (K±)) larger. These results are useful for the phenomenological analysis of the Bc meson decays into P-wave charmonium, which shall be tested in the LHCb experiments.

Meson Production and Decays with WASA at COSY

DOE Office of Scientific and Technical Information (OSTI.GOV)

Schadmand, Susan

2011-10-21

The WASA-at-COSY physics program focuses on light meson decays where rare decays are used to scrutinize symmetries and symmetry breaking. The structure of hadrons is probed with transition form factors and hadron spectroscopy while hadron dynamics is studied via reaction dynamics and few body reactions.

High-precision half-life determination for the superallowed β+ emitter Ga62

NASA Astrophysics Data System (ADS)

Grinyer, G. F.; Finlay, P.; Svensson, C. E.; Ball, G. C.; Leslie, J. R.; Austin, R. A. E.; Bandyopadhyay, D.; Chaffey, A.; Chakrawarthy, R. S.; Garrett, P. E.; Hackman, G.; Hyland, B.; Kanungo, R.; Leach, K. G.; Mattoon, C. M.; Morton, A. C.; Pearson, C. J.; Phillips, A. A.; Ressler, J. J.; Sarazin, F.; Savajols, H.; Schumaker, M. A.; Wong, J.

2008-01-01

The half-life of the superallowed β+ emitter Ga62 has been measured at TRIUMF's Isotope Separator and Accelerator facility using a fast-tape-transport system and 4π continuous-flow gas proportional counter to detect the positrons from the decay of Ga62 to the daughter Zn62. The result, T1/2=116.100±0.025 ms, represents the most precise measurement to date (0.022%) for any superallowed β-decay half-life. When combined with six previous measurements of the Ga62 half-life, a new world average of T1/2=116.121±0.021 ms is obtained. This new half-life measurement results in a 20% improvement in the precision of the Ga62 superallowed ft value while reducing its mean by 0.9σ to ft=3074.3(12) s. The impact of this half-life measurement on precision tests of the CVC hypothesis and isospin symmetry breaking corrections for A⩾62 superallowed decays is discussed.

Decay Pattern of Pygmy States Observed in Neutron-Rich Ne26

NASA Astrophysics Data System (ADS)

Gibelin, J.; Beaumel, D.; Motobayashi, T.; Blumenfeld, Y.; Aoi, N.; Baba, H.; Elekes, Z.; Fortier, S.; Frascaria, N.; Fukuda, N.; Gomi, T.; Ishikawa, K.; Kondo, Y.; Kubo, T.; Lima, V.; Nakamura, T.; Saito, A.; Satou, Y.; Scarpaci, J.-A.; Takeshita, E.; Takeuchi, S.; Teranishi, T.; Togano, Y.; Vinodkumar, A. M.; Yanagisawa, Y.; Yoshida, K.

2008-11-01

Coulomb excitation of the exotic neutron-rich nucleus Ne26 on a Pb208 target was measured at 58MeV/u in order to search for low-lying E1 strength above the neutron emission threshold. This radioactive beam experiment was carried out at the RIKEN Accelerator Research Facility. Using the invariant mass method in the Ne25+n channel, we observe a sizable amount of E1 strength between 6 and 10 MeV excitation energy. By performing a multipole decomposition of the differential cross section, a reduced dipole transition probability of B(E1)=0.49±0.16e2fm2 is deduced, corresponding to 4.9±1.6% of the Thomas-Reiche-Kuhn sum rule. For the first time, the decay pattern of low-lying strength in a neutron-rich nucleus is measured. The extracted decay pattern is not consistent with several mean-field theory descriptions of the pygmy states.

Social-emotional characteristics of gifted accelerated and non-accelerated students in the Netherlands.

PubMed

Hoogeveen, Lianne; van Hell, Janet G; Verhoeven, Ludo

2012-12-01

In the studies of acceleration conducted so far a multidimensional perspective has largely been neglected. No attempt has been made to relate social-emotional characteristics of accelerated versus non-accelerated students in perspective of environmental factors. In this study, social-emotional characteristics of accelerated gifted students in the Netherlands were examined in relation to personal and environmental factors. Self-concept and social contacts of accelerated (n = 148) and non-accelerated (n = 55) gifted students, aged 4 to 27 (M = 11.22, SD = 4.27) were measured. Self-concept and social contacts of accelerated and non-accelerated gifted students were measured using a questionnaire and a diary, and parents of these students evaluated their behavioural characteristics. Gender and birth order were studied as personal factors and grade, classroom, teachers' gender, teaching experience, and the quality of parent-school contact as environmental factors. The results showed minimal differences in the social-emotional characteristics of accelerated and non-accelerated gifted students. The few differences we found favoured the accelerated students. We also found that multiple grade skipping does not have negative effects on social-emotional characteristics, and that long-term effects of acceleration tend to be positive. As regards the possible modulation of personal and environmental factors, we merely found an impact of such factors in the non-accelerated group. The results of this study strongly suggest that social-emotional characteristics of accelerated gifted students and non-accelerated gifted students are largely similar. These results thus do not support worries expressed by teachers about the acceleration of gifted students. Our findings parallel the outcomes of earlier studies in the United States and Germany in that we observed that acceleration does not harm gifted students, not even in the case of multiple grade skipping. On the contrary, there is a suggestion in the data that accelerated students are more socially competent than non-accelerated students. The findings in this study can reassure those parents and teachers who worry about the social-emotional consequences of acceleration in school: If a student is gifted, acceleration seems to be a sound and, in many cases, appropriate measure in gifted education. ©2011 The British Psychological Society.

Effects of temperature on type approval testing of ballast water treatment systems.

PubMed

Drillet, Guillaume; Schmoker, Claire; Trottet, Aurore; Mahjoub, Mohamed-Sofiane; Duchemin, Matthieu; Andersen, Martin

2013-04-01

To limit the risk associated with invasion of habitats by exogenous species, the International Convention for the Control and Management of the Ships' Ballast Water and Sediments was adopted in February 2004 and may soon enter into force. The International Maritime Organization (IMO) has produced guidelines to assess the efficacy and reliability of Ballast Water Treatment Systems (BWTS), but no guidance on how to take temperature into account during test cycles has been provided yet. Temperature is one of the main factors influencing the distribution and ecology of organisms along latitudes. Its increase results in higher grazing, growth, and reproduction rates of zooplankton. Under dark conditions, phytoplankton loss is also increased due to faster natural decay as well as enhanced top down control from zooplankton. Increased temperatures also improve the efficacy of chemical treatment, whereas the decay rates of disinfectants and their byproducts are potentially accelerated. The IMO guidelines for the type approval of BWTS should be amended to include recommendations on how to take temperature into account. Failing to ensure comparability and reliability between tests may pose a threat to the environment and may create problems for those attempting to apply BWTS. We propose to use a fixed Q10 value and a temperature of reference to adjust the retention time in ballast water tanks during testing. Copyright © 2013 SETAC.

Measurement of the Hadronic Charm Production Cross-Section in a High Resolution Streamer Chamber Experiment

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tzeng, Liang

1984-05-01

Hadronic production of charmed particles in association with muons from semileptonic decay or. these short lived particles has been observed in a high resolution streamer cham her experiment performed at Fermi National Accelerator Laboratory in 1982. The incident beam was a collimated high energy neutron beam with an average energy or 280 Gev. The streamer cham her was triggered on the detection or the prom pt muon from the charm decay. Two toroids were installed at the downstream end or the muon spectrometer for analyzing the muon momentum. In the operation of the streamer chamber, we achieved a streamer size or 50 μm and a run track width or 120 μm in space. The streamer chamber optical system had a demagnification factor of about 1.5 from space to film. The minimum separation between two measurable tracks was about 150 μm on the film. With a special miss-distance analysis or the streamer chamber pictures. 17.32 ± 4.73 charm signal events were obtained. Using the assumption ofmore » $$A^{2/3}$$ dependenre for the production cross section and several different $$D-\\bar{D}$$ production models, the nucleonnucleon charm production cross section, averaged over the neutron spectrum, is estimated to be between 13 to 20 μb (with the average value equal to 17.69 ± 6.80 μb).« less

Measurements of 67Ga production cross section induced by protons on natZn in the low energy range from 1.678 to 2.444 MeV

NASA Astrophysics Data System (ADS)

Wachter, J. A.; Miranda, P. A.; Morales, J. R.; Cancino, S. A.; Correa, R.

2015-02-01

The experimental production cross section for the reaction natZn(p,x)67Ga has been measured in the energy range from 1.678 to 2.444 MeV. The methodology used in this work is based on characteristic X-ray emitted after irradiation by the daughter nuclei that decays by electron capture (EC) and the use of a complementary PIXE experiment. By doing so, expressions needed to determine cross section values are simplified since experimental factors such as geometric setup and an detector efficiency are avoided. 67Ga is a radionuclide particularly suited for this method since it decays by electron capture in 100% and the subsequent characteristic X-ray emission is easily detected. Natural zinc targets were fabricated by PVD technique and afterwards their thicknesses were determined by Rutherford Backscattering Spectrometry. Cross sections measurements were carried out by using the Van de Graaff accelerator located at Faculty of Sciences, University of Chile. It was found that our data for the natZn(p,x)67Ga reaction are, in general, in good agreement when compared to existing experimental data and to those calculated ALICE/ASH nuclear code. On the other hand, values predicted by Talys-1.6 are showing systematically lower magnitudes than our measured data.

Accelerated T1ρ acquisition for knee cartilage quantification using compressed sensing and data-driven parallel imaging: A feasibility study.

PubMed

Pandit, Prachi; Rivoire, Julien; King, Kevin; Li, Xiaojuan

2016-03-01

Quantitative T1ρ imaging is beneficial for early detection for osteoarthritis but has seen limited clinical use due to long scan times. In this study, we evaluated the feasibility of accelerated T1ρ mapping for knee cartilage quantification using a combination of compressed sensing (CS) and data-driven parallel imaging (ARC-Autocalibrating Reconstruction for Cartesian sampling). A sequential combination of ARC and CS, both during data acquisition and reconstruction, was used to accelerate the acquisition of T1ρ maps. Phantom, ex vivo (porcine knee), and in vivo (human knee) imaging was performed on a GE 3T MR750 scanner. T1ρ quantification after CS-accelerated acquisition was compared with non CS-accelerated acquisition for various cartilage compartments. Accelerating image acquisition using CS did not introduce major deviations in quantification. The coefficient of variation for the root mean squared error increased with increasing acceleration, but for in vivo measurements, it stayed under 5% for a net acceleration factor up to 2, where the acquisition was 25% faster than the reference (only ARC). To the best of our knowledge, this is the first implementation of CS for in vivo T1ρ quantification. These early results show that this technique holds great promise in making quantitative imaging techniques more accessible for clinical applications. © 2015 Wiley Periodicals, Inc.

Electron and ion acceleration in relativistic shocks with applications to GRB afterglows

NASA Astrophysics Data System (ADS)

Warren, Donald C.; Ellison, Donald C.; Bykov, Andrei M.; Lee, Shiu-Hang

2015-09-01

We have modelled the simultaneous first-order Fermi shock acceleration of protons, electrons, and helium nuclei by relativistic shocks. By parametrizing the particle diffusion, our steady-state Monte Carlo simulation allows us to follow particles from particle injection at non-relativistic thermal energies to above PeV energies, including the non-linear smoothing of the shock structure due to cosmic ray (CR) backpressure. We observe the mass-to-charge (A/Z) enhancement effect believed to occur in efficient Fermi acceleration in non-relativistic shocks and we parametrize the transfer of ion energy to electrons seen in particle-in-cell (PIC) simulations. For a given set of environmental and model parameters, the Monte Carlo simulation determines the absolute normalization of the particle distributions and the resulting synchrotron, inverse Compton, and pion-decay emission in a largely self-consistent manner. The simulation is flexible and can be readily used with a wide range of parameters typical of γ-ray burst (GRB) afterglows. We describe some preliminary results for photon emission from shocks of different Lorentz factors and outline how the Monte Carlo simulation can be generalized and coupled to hydrodynamic simulations of GRB blast waves. We assume Bohm diffusion for simplicity but emphasize that the non-linear effects we describe stem mainly from an extended shock precursor where higher energy particles diffuse further upstream. Quantitative differences will occur with different diffusion models, particularly for the maximum CR energy and photon emission, but these non-linear effects should be qualitatively similar as long as the scattering mean-free path is an increasing function of momentum.

Heritable patterns of tooth decay in the permanent dentition: principal components and factor analyses.

PubMed

Shaffer, John R; Feingold, Eleanor; Wang, Xiaojing; Tcuenco, Karen T; Weeks, Daniel E; DeSensi, Rebecca S; Polk, Deborah E; Wendell, Steve; Weyant, Robert J; Crout, Richard; McNeil, Daniel W; Marazita, Mary L

2012-03-09

Dental caries is the result of a complex interplay among environmental, behavioral, and genetic factors, with distinct patterns of decay likely due to specific etiologies. Therefore, global measures of decay, such as the DMFS index, may not be optimal for identifying risk factors that manifest as specific decay patterns, especially if the risk factors such as genetic susceptibility loci have small individual effects. We used two methods to extract patterns of decay from surface-level caries data in order to generate novel phenotypes with which to explore the genetic regulation of caries. The 128 tooth surfaces of the permanent dentition were scored as carious or not by intra-oral examination for 1,068 participants aged 18 to 75 years from 664 biological families. Principal components analysis (PCA) and factor analysis (FA), two methods of identifying underlying patterns without a priori surface classifications, were applied to our data. The three strongest caries patterns identified by PCA recaptured variation represented by DMFS index (correlation, r = 0.97), pit and fissure surface caries (r = 0.95), and smooth surface caries (r = 0.89). However, together, these three patterns explained only 37% of the variability in the data, indicating that a priori caries measures are insufficient for fully quantifying caries variation. In comparison, the first pattern identified by FA was strongly correlated with pit and fissure surface caries (r = 0.81), but other identified patterns, including a second pattern representing caries of the maxillary incisors, were not representative of any previously defined caries indices. Some patterns identified by PCA and FA were heritable (h(2) = 30-65%, p = 0.043-0.006), whereas other patterns were not, indicating both genetic and non-genetic etiologies of individual decay patterns. This study demonstrates the use of decay patterns as novel phenotypes to assist in understanding the multifactorial nature of dental caries.

Detection of Adriamycin–DNA adducts by accelerator mass spectrometry at clinically relevant Adriamycin concentrations

PubMed Central

Coldwell, Kate E.; Cutts, Suzanne M.; Ognibene, Ted J.; Henderson, Paul T.; Phillips, Don R.

2008-01-01

Limited sensitivity of existing assays has prevented investigation of whether Adriamycin–DNA adducts are involved in the anti-tumour potential of Adriamycin. Previous detection has achieved a sensitivity of a few Adriamycin–DNA adducts/104 bp DNA, but has required the use of supra-clinical drug concentrations. This work sought to measure Adriamycin–DNA adducts at sub-micromolar doses using accelerator mass spectrometry (AMS), a technique with origins in geochemistry for radiocarbon dating. We have used conditions previously validated (by less sensitive decay counting) to extract [14C]Adriamycin–DNA adducts from cells and adapted the methodology to AMS detection. Here we show the first direct evidence of Adriamycin–DNA adducts at clinically-relevant Adriamycin concentrations. [14C]Adriamycin treatment (25 nM) resulted in 4.4 ± 1.0 adducts/107 bp (∼1300 adducts/cell) in MCF-7 breast cancer cells, representing the best sensitivity and precision reported to date for the covalent binding of Adriamycin to DNA. The exceedingly sensitive nature of AMS has enabled over three orders of magnitude increased sensitivity of Adriamycin–DNA adduct detection and revealed adduct formation within an hour of drug treatment. This method has been shown to be highly reproducible for the measurement of Adriamycin–DNA adducts in tumour cells in culture and can now be applied to the detection of these adducts in human tissues. PMID:18632763

Measurement of the Branching Ratio of the charmless decay B s → φφ at CDFII

DOE Office of Scientific and Technical Information (OSTI.GOV)

Di Ruzza, Benedetto

2008-01-01

We present a study of the charmless B s → φφ decay performed with the CDFII detector at the Fermilab Tevatron Collider. Charmless B0 decays currently can be studied only at the Tevatron and represent a field still to be fully explored that offers additional ways to test our present theoretical understanding. The B s → φφ belongs to a particular class of these decays: the B s meson decays into a pair of vector particle and the fi al state is self- conjugate. It can be used to measure the B s decay width difference (ΓΔs), to improve ourmore » understanding about the Cabibbo Kobayashi Maskawa matrix, and to perform tests of decay polarization predictions. The B s → φφ decay proceeds through a b → sss transition and in the Standard Model the dominant process is the b → s “penguin” diagram. The same penguin amplitude is involved in several processes which have shown several discrepancies with the Standard Model predictions, raising considerable attention on the theoretical side and new physics interpretations have been considered to explain the experimental data. To shed light on this experimental and theoretical rather complex scenario, new and more precise measurements are clearly needed in as many interesting channels as possible. The study of B s → φφ channel is an important player in this experimental effort. The B s → φφ decay has been observed for the first time by CDF in 2005 [1] in a data sample of 180 pb -1; eight events have been seen and a first measurement of the Branching Ratio (BR) has been performed. In this thesis we present an update of this measurement with an integrated luminosity of 2.9fb -1. An improvement of a factor 5 compared to the previous Branching Ratio measurement is achieved. In Chap.2 a short introduction on the Standard Model with special emphasis on the electroweak sector is presented. In Chap.3 the Fermilab accelerator complex and the CDFII detector is described. The trigger strategy to select events relevant to B physics is explained in some detail. In Chap.4 we present the data sample used for this analysis and some informations concerning the offline reconstruction program. In Chap.5 the Monte Carlo program and its validation procedure are explained. In Chap.6 the strategy of the Branching Ratio measurement and the optimization procedure used to define the analysis selection criteria both for the B s → φφ and the B s → J/ψφ decays are presented. In Chap.7 all the steps needed to perform the measurement of the BR are reported. Signal yields of the B s → φφ and the B s → J/ψφ decays are presented. The trigger and selection efficiencies and the muon efficiency are evaluated. The ratio of the BR(B s → φφ) to the BR(B s → J/ψφ) is measured and is used to compute the Branching Ratio of B s → φφ. The systematic errors on the BR are estimated. In Chap.8 we present the summary of our results.« less

Enterovirus strain and type-specific differences in growth kinetics and virus-induced cell destruction in human pancreatic duct epithelial HPDE cells.

PubMed

Smura, Teemu; Natri, Olli; Ylipaasto, Petri; Hellman, Marika; Al-Hello, Haider; Piemonti, Lorenzo; Roivainen, Merja

2015-12-02

Enterovirus infections have been suspected to be involved in the development of type 1 diabetes. However, the pathogenetic mechanism of enterovirus-induced type 1 diabetes is not known. Pancreatic ductal cells are closely associated with pancreatic islets. Therefore, enterovirus infections in ductal cells may also affect beta-cells and be involved in the induction of type 1 diabetes. The aim of this study was to assess the ability of different enterovirus strains to infect, replicate and produce cytopathic effect in human pancreatic ductal cells. Furthermore, the viral factors that affect these capabilities were studied. The pancreatic ductal cells were highly susceptible to enterovirus infections. Both viral growth and cytolysis were detected for several enterovirus serotypes. However, the viral growth and capability to induce cytopathic effect (cpe) did not correlate completely. Some of the virus strains replicated in ductal cells without apparent cpe. Furthermore, there were strain-specific differences in the growth kinetics and the ability to cause cpe within some serotypes. Viral adaptation experiments were carried out to study the potential genetic determinants behind these phenotypic differences. The blind-passage of non-lytic CV-B6-Schmitt strain in HPDE-cells resulted in lytic phenotype and increased progeny production. This was associated with the substitution of a single amino acid (K257E) in the virus capsid protein VP1 and the viral ability to use decay accelerating factor (DAF) as a receptor. This study demonstrates considerable plasticity in the cell tropism, receptor usage and cytolytic properties of enteroviruses and underlines the strong effect of single or few amino acid substitutions in cell tropism and lytic capabilities of a given enterovirus. Since ductal cells are anatomically close to pancreatic islets, the capability of enteroviruses to infect and destroy pancreatic ductal cells may also implicate in respect to enterovirus induced type 1 diabetes. In addition, the capability for rapid adaptation to different cell types suggests that, on occasion, enterovirus strains with different pathogenetic properties may arise from less pathogenic ancestors. Copyright © 2015 Elsevier B.V. All rights reserved.

A study of w boson decay charge asymmetry using hadronic tau decays in proton - anti-proton collisions at √s = 1.8 TeV

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kuns, Edward William

This dissertation presents a measurement of the tau charge asymmetry in events where the taus are produced by W decays. This charge asymmetry appears as different rapidity distributions for positive and negative taus. Two competing effects generate tau charge asymmetry. The production mechanism for the W gauge boson generates a charge asymmetry which is a function of the ratio of parton distribution functions, d(x)=u(x), measured at x ~ M W/√s. This is the dominant effect for tau charge asymmetry at small rapidity. At higher rapidity, however, the competing charge asymmetry from parity violation in W decay to taus becomes dominant. This tau asymmetry measurement is consistent with the Standard Model with a x 2 per degree of freedom equal to 2.5 for 4 degrees of freedom when the asymmetry measurement is folded about y = 0, taking advantage of the CP symmetry of the underlying physics, and 8.9 for 8 degrees of freedom when it is not. This measurement introduces some methods and variables of interest to future analyses using hadronic decay modes of taus. This work was done using the CDF detector inmore » $$\\bar{p}$$p collisions at √s = 1.8 TeV at Fermilab's Tevatron accelerator.« less

Food allergy trends at the crossing among socio-economics, history and geography.

PubMed

Fiocchi, Alessandro; Dahdah, Lamia; Fierro, Vincenzo; Artesani, Maria C; Valluzzi, Rocco

2018-06-01

The epidemiology of food allergy did inspire theories on the reasons for the recent surge of the disease. We offer here a reasoned review on the relationships between the trajectories of human development and the trend of the food allergy epidemics. The exponential trend of the frequency of food allergy paralleled the explosive acceleration of the human development over the last few decades. Dietary factors have been indicated as responsible for these trends and targeted for potential preventive strategies. Other socio-economic factors have been related to this evolution: solar exposure, climate changes, structure of societies, reproductive choices and societal inequalities. The epidemiologic associations of food allergy suggest different causal theories. Future prevention strategies may be predicated not only on dietary interventions, but on wider programmes aimed to restore a human ecology promoting food tolerance.

The trigger system for K0→2 π0 decays of the NA48 experiment at CERN

NASA Astrophysics Data System (ADS)

Mikulec, I.

1998-02-01

A fully pipelined 40 MHz "dead-time-free" trigger system for neutral K0 decays for the NA48 experiment at CERN is described. The NA48 experiment studies CP-violation using the high intensity beam of the CERN SPS accelerator. The trigger system sums, digitises, filters and processes signals from 13 340 channels of the liquid krypton electro-magnetic calorimeter. In 1996 the calorimeter and part of the trigger electronics were installed and tested. In 1997 the system was completed and prepared to be used in the first NA48 physics data taking period. Cagliari, Cambridge, CERN, Dubna, Edinburgh, Ferrara, Firenze, Mainz, Orsay, Perugia, Pisa, Saclay, Siegen, Torino, Warszawa, Wien Collaboration.

Decoherence control mechanisms of a charged magneto-oscillator in contact with different environments

NASA Astrophysics Data System (ADS)

Rajesh, Asam; Bandyopadhyay, Malay; Jayannavar, Arun M.

2017-12-01

In this work, we consider two different techniques based on reservoir engineering process and quantum Zeno control method to analyze the decoherence control mechanism of a charged magneto-oscillator in contact with different type of environment. Our analysis reveals that both the control mechanisms are very much sensitive on the details of different environmental spectrum (J (ω)), and also on different system and reservoir parameters, e.g., external magnetic field (rc), confinement length (r0), temperature (T), cut-off frequency of reservoir spectrum (ωcut), and measurement interval (τ). We also demonstrate the manipulation scheme of the continuous passage from decay suppression to decay acceleration by tuning the above mentioned system or reservoir parameters, e.g., rc, r0, T and τ.

Proton-induced accelerated decay of the fungicide, vinclozolin, on TiO2 surface under solar irradiation: Experimental and DFT study.

PubMed

Osipov, Ivan; Gorbachev, Mikhail Y; Gorinchoy, Natalia N

2018-04-03

The photochemical degradation of vinclozolin by addition of titanium dioxide on silica support has been examined both experimental and quantum-chemically. Solar irradiation of vinclozolin on silica with and without addition of titanium dioxide for 6 h resulted in 21% and 97.8% vinclozolin residues, respectively. In both these cases, phototransformation leads to the formation of (3,5-dichlorophenyl isocyanate) and (3,5-dichloroaniline). The presence of the intermediary product resulted from opening of the 2,4-oxazolidine-dione ring is also confirmed by GS-MS and LC-MS chromatography. The proton-induced mechanism of vinclozolin decay at the above experimental conditions is clarified on the base of DFT calculations.

Second-Order Chlorine Decay and Trihalomethanes Formation in a Pilot-Scale Water Distribution Systems

EPA Science Inventory

It is well known that model-building of chlorine decay in real water distribution systems is difficult because chlorine decay is influenced by many factors (e.g., bulk water demand, pipe-wall demand, piping material, flow velocity, and residence time). In this paper, experiments ...

Calculated and TLD-based absorbed dose estimates for I-131-labeled 3F8 monoclonal antibody in a human neuroblastoma xenograft nude mouse model.

PubMed

Ugur, O; Scott, A M; Kostakoglu, L; Hui, T E; Masterson, M E; Febo, R; Sgouros, G; Rosa, E; Mehta, B M; Fisher, D R

1995-01-01

Preclinical evaluation of the therapeutic potential of radiolabeled antibodies is commonly performed in a xenografted nude mouse model. To assess therapeutic efficacy it is important to estimate the absorbed dose to the tumor and normal tissues of the nude mouse. The current study was designed to accurately measure radiation does to human neuroblastoma xenografts and normal organs in nude mice treated with I-131-labeled 3F8 monoclonal antibody (MoAb) against disialoganglioside GD2 antigen. Absorbed dose estimates were obtained using two different approaches: (1) measurement with teflon-imbedded CaSO4:Dy mini-thermoluminescent dosimeters (TLDs) and (2) calculations using mouse S-factors. The calculated total dose to tumor one week after i.v. injection of the 50 microCi I-131-3F8 MoAb was 604 cGy. The corresponding decay corrected and not corrected TLD measurements were 109 +/- 9 and 48.7 +/- 3.4 cGy respectively. The calculated to TLD-derived dose ratios for tumor ranged from 6.1 at 24 h to 5.5 at 1 week. The light output fading rate was found to depend upon the tissue type within which the TLDs were implanted. The decay rate in tumor, muscle, subcutaneous tissue and in vitro, were 9.5, 5.0, 3.7 and 0.67% per day, respectively. We have demonstrated that the type of tissue in which the TLD was implanted strongly influenced the in vivo decay of light output. Even with decay correction, a significant discrepancy was observed between MIRD-based calculated and CaSO4:Dy mini-TLD measured absorbed doses. Batch dependence, pH of the tumor or other variables associated with TLDs which are not as yet well known may account for this discrepancy.

The role of hesperetin on osteogenesis of human mesenchymal stem cells and its function in bone regeneration.

PubMed

Xue, Deting; Chen, Erman; Zhang, Wei; Gao, Xiang; Wang, Shengdong; Zheng, Qiang; Pan, Zhijun; Li, Hang; Liu, Ling

2017-03-28

Hesperetin has been suggested to be involved in bone strength. We aimed to investigate the effects of hesperetin on the osteogenic differentiation of human mesenchymal stem cells and its related mechanisms. We showed that hesperetin promoted osteogenic differentiation of human mesenchymal stem cells in vitro. It potentially exerts its effects via the ERK and Smad signaling pathways. Using a rat osteotomy model, we showed that human mesenchymal stem cells combined with a hesperetin/gelatin sponge scaffold resulted in accelerated fracture healing in vivo. Due to the low cost of hesperetin, it could be used as a growth factor for bone tissue engineering or surgical fracture treatment.

Preoperative predictors of returning to work following primary total knee arthroplasty.

PubMed

Styron, Joseph F; Barsoum, Wael K; Smyth, Kathleen A; Singer, Mendel E

2011-01-05

There is little in the literature to guide clinicians in advising patients regarding their return to work following a primary total knee arthroplasty. In this study, we aimed to identify which factors are important in estimating a patient's time to return to work following primary total knee arthroplasty, how long patients can anticipate being off from work, and the types of jobs to which patients are able to return following primary total knee arthroplasty. A prospective cohort study was performed in which patients scheduled for a primary total knee arthroplasty completed a validated questionnaire preoperatively and at four to six weeks, three months, and six months postoperatively. The questionnaire assessed the patient's occupational physical demands, ability to perform job responsibilities, physical status, and motivation to return to work as well as factors that may impact his or her recovery and other workplace characteristics. Two survival analysis models were constructed to evaluate the time to return to work either at least part-time or full-time. Acceleration factors were calculated to indicate the relative percentage of time until the patient returned to work. The median time to return to work was 8.9 weeks. Patients who reported a sense of urgency about returning to work were found to return in half the time taken by other employees (acceleration factor = 0.468; p < 0.001). Other preoperative factors associated with a faster return to work included being female (acceleration factor = 0.783), self-employment (acceleration factor = 0.792), higher mental health scores (acceleration factor = 0.891), higher physical function scores (acceleration factor = 0.809), higher Functional Comorbidity Index scores (acceleration factor = 0.914), and a handicap accessible workplace (acceleration factor = 0.736). A slower return to work was associated with having less pain preoperatively (acceleration factor = 1.132), having a more physically demanding job (acceleration factor = 1.116), and receiving Workers' Compensation (acceleration factor = 4.360). Although the physical demands of a patient's job have a moderate influence on the patient's ability to return to work following a primary total knee arthroplasty, the patient's characteristics, particularly motivation, play a more important role.

High-energy phosphate metabolism during incremental calf exercise in humans measured by 31 phosphorus magnetic resonance spectroscopy (31P MRS).

PubMed

Schocke, Michael F H; Esterhammer, Regina; Kammerlander, Christian; Rass, Anton; Kremser, Christian; Fraedrich, Gustav; Jaschke, Werner R; Greiner, Andreas

2004-01-01

Several previous 31 phosphorus magnetic resonance spectroscopy ((31)P MRS) studies performing incremental or progressive muscle exercises have observed that a decrease in pH is accompanied with an acceleration in phosphocreatine (PCr) hydrolysis. The purpose of this study was to investigate the relationship between PCr breakdown and pH during isotonic, exhaustive, incremental plantar flexion exercises. We included eight healthy, male volunteers into this study. Using a 1.5 Tesla MR scanner and a self-built exercise bench, we performed serial free induction decay (FID) (31)P MRS measurements with a time resolution of 1 min at rest, isotonic calf muscle exercise, and recovery. The exercise protocol consisted of 5-min intervals with 4.5, 6, 7.5, and 9 W workload followed by 9-min recovery. Changes in PCr and inorganic phosphate (Pi) were determined as percent changes in comparison to the baseline. In addition, pH values were calculated. This study obtained significant decreases in PCr corresponding to the gradual increases in workload. In each workload level that was succeeded by all volunteers, PCr hydrolysis passed into a steady state. After an early biphasic response, we detected a significant decrease in pH from the first to the second minute of the 6-W workload level followed by a further continuous decrease in pH up to the second minute of the recovery phase. The decrease in pH was not accompanied by acceleration in PCr hydrolysis. In conclusion, this study shows that PCr hydrolysis during incremental plantar flexion exercises passes into a steady state at different workload levels. The observed decrease in pH does not result in acceleration of PCr hydrolysis.

Testing QCD factorization with phase determinations in B →K π , K ρ , and K*π decays

NASA Astrophysics Data System (ADS)

Pham, T. N.

2016-06-01

The success of QCD factorization (QCDF) in predicting branching ratios for charmless B decays to light pseudoscalar and vector mesons and the small C P asymmetries measured at BABAR, Belle, and LHCb show that the phase in these decays, as predicted by QCDF, are not large. For a precise test of QCDF, one needs to extract from the measured decay rates the phase of the decay amplitude which appears in the interference terms between the tree and penguin contribution. Since the tree amplitude is known at the leading order in ΛQCD/mb and is consistent with the measured tree-dominated decay rates, the QCDF value for the tree amplitude can be used with the measured decay rates to obtain the phases in B →K π , K ρ , and K*π decay rates. This is similar to the extraction of the final-state interaction phases in the interference term between p p ¯→J /Ψ →e+e- and p p ¯→e+e- and in J /Ψ →0-0- done previously. In this paper, we present a determination of the phase between the I =3 /2 tree and I =1 /2 penguin amplitudes in B →K π , K ρ , and K*π decays using the measured decay rates and the QCDF I =3 /2 tree amplitude obtained from the I =2 B+→π+π0,ρ0π+,ρ+π0 tree-dominated decays and compare the result with the phase given by QCDF. It is remarkable that the phase extracted from experiments differs only slightly from the QCDF values. This shows that there is no large final-state interaction strong phase in B →K π , K ρ , and K*π decays.

Nitric Oxide Increases the Decay of Matrix Metalloproteinase 9 mRNA by Inhibiting the Expression of mRNA-Stabilizing Factor HuR

PubMed Central

Akool, El-Sayed; Kleinert, Hartmut; Hamada, Farid M. A.; Abdelwahab, Mohamed H.; Förstermann, Ulrich; Pfeilschifter, Josef; Eberhardt, Wolfgang

2003-01-01

Dysregulation of extracellular matrix turnover is an important feature of many inflammatory processes. Rat renal mesangial cells express high levels of matrix metalloproteinase 9 (MMP-9) in response to inflammatory cytokines such as interleukin-1 beta. We demonstrate that NO does strongly destabilize MMP-9 mRNA, since different luciferase reporter gene constructs containing the MMP-9 3′ untranslated region (UTR) displayed significant reduced luciferase activity in response to the presence of NO. Moreover, by use of an in vitro degradation assay we found that the cytoplasmic fractions of NO-treated cells contained a higher capacity to degrade MMP-9 transcripts than those obtained from control cells. An RNA electrophoretic mobility shift assay demonstrated that three of four putative AU-rich elements present in the 3′ UTR of MMP-9 were constitutively occupied by the mRNA-stabilizing factor HuR and that the RNA binding was strongly attenuated by the presence of NO. The addition of recombinant glutathione transferase-HuR prevented the rapid decay of MMP-9 mRNA, whereas the addition of a neutralizing anti-HuR antibody caused an acceleration of MMP-9 mRNA degradation. Furthermore, the expression of HuR mRNA and protein was significantly reduced by exogenously and endogenously produced NO. These inhibitory effects were mimicked by the cGMP analog 8-bromo-cGMP and reversed by LY-83583, an inhibitor of soluble guanylyl cyclase. These results demonstrate that NO acts in a cGMP-dependent mechanism to inhibit the expression level of HuR, thereby reducing the stability of MMP-9 mRNA. PMID:12832476

Decay {B to K^ast(to Kπ)ℓ+ ℓ-} in Covariant Quark Model

NASA Astrophysics Data System (ADS)

Dubnička, S.; Dubničková, A. Z.; Habyl, N.; Ivanov, M. A.; Liptaj, A.; Nurbakova, G. S.

2016-03-01

Our article is devoted to the study of the rare {B to K^ast ℓ^+ℓ^-} decay where {ℓ=e,μ,τ}. We compute the relevant form factors in the framework of the covariant quark model with infrared confinement in the full kinematical momentum transfer region. The calculated form factors are used to evaluate branching fractions and polarization observables in the cascade decay {B to K^ast(to Kπ)ℓ^+ℓ^-}. We compare the obtained results with available experimental data and the results from other theoretical approaches.

Near-Unity Internal Quantum Efficiency of Luminescent Silicon Nanocrystals with Ligand Passivation.

PubMed

Sangghaleh, Fatemeh; Sychugov, Ilya; Yang, Zhenyu; Veinot, Jonathan G C; Linnros, Jan

2015-07-28

Spectrally resolved photoluminescence (PL) decays were measured for samples of colloidal, ligand-passivated silicon nanocrystals. These samples have PL emission energies with peak positions in the range ∼1.4-1.8 eV and quantum yields of ∼30-70%. Their ensemble PL decays are characterized by a stretched-exponential decay with a dispersion factor of ∼0.8, which changes to an almost monoexponential character at fixed detection energies. The dispersion factors and decay rates for various detection energies were extracted from spectrally resolved curves using a mathematical approach that excluded the effect of homogeneous line width broadening. Since nonradiative recombination would introduce a random lifetime variation, leading to a stretched-exponential decay for an ensemble, we conclude that the observed monoexponential decay in size-selected ensembles signifies negligible nonradiative transitions of a similar strength to the radiative one. This conjecture is further supported as extracted decay rates agree with radiative rates reported in the literature, suggesting 100% internal quantum efficiency over a broad range of emission wavelengths. The apparent differences in the quantum yields can then be explained by a varying fraction of "dark" or blinking nanocrystals.

In vivo assessment of magnesium status in human body using accelerator-based neutron activation measurement of hands: a pilot study.

PubMed

Aslam; Pejović-Milić, A; McNeill, F E; Byun, S H; Prestwich, W V; Chettle, D R

2008-02-01

Magnesium (Mg) is an element essential for many enzymatic reactions in the human body. Various human and animal studies suggest that changes in Mg status are linked to diseases such as cardiac arrhythmia, coronary heart disease, hypertension, premenstrual syndrome, and diabetes mellitus. Thus, knowledge of Mg levels in the human body is needed. A direct measurement of human blood serum, which contains only 0.3% of the total body Mg, is generally used to infer information about the status of Mg in the body. However, in many clinical situations, Mg stored in large levels, for example in bones, muscles, and soft tissues, needs to be monitored either to evaluate the efficacy of a treatment or to study the progression of diseases associated with the deficiency of total body Mg. This work presents a feasibility study of a noninvasive, in vivo neutron activation analysis (IVNAA) technique using the 26Mg (n, gamma) 27Mg reaction to measure Mg levels in human hands. The technique employs the McMaster University high beam current Tandetron accelerator hand irradiation facility and an array of eight NaI (T1) detectors arranged in a 4 pi geometry for delayed counting of the 0.844 and 1.014 MeV gamma rays emitted when 27Mg decays in the irradiated hand. Mg determination in humans using IVNAA of hands has been demonstrated to be feasible, with effective doses as low as one-quarter of those delivered in chest x rays. The overall experimental uncertainty in the measurements is estimated to be approximately 5% (1 sigma). The results are found to be in the range of the in vitro measurements reported for other cortical bones collected from different sites of the human skeleton, which confirms that this technique mainly provides a measure of the amount of Mg in hand bones. The average concentration of Mg determined in human hands is 10.96 +/- 1.25 (+/- 1 SD) mg Mg/g Ca. The coefficient of variation (11%) observed in this study is comparable with or lower than several studies using in vitro measurements reported in the literature and therefore allows for a quantitative intersubject comparison, even if to a limited extent. The features of the developed technique such as its simplicity, rapidity, accuracy, robustness, noninvasive nature, and very effective use of radiation doses, present the technique as a viable diagnostic tool available for trial in a clinical environment.

Anatomy of Bs → PV decays and effects of next-to-leading order contributions in the perturbative QCD factorization approach

NASA Astrophysics Data System (ADS)

Yan, Da-Cheng; Yang, Ping; Liu, Xin; Xiao, Zhen-Jun

2018-06-01

In this paper, we will make systematic calculations for the branching ratios and the CP-violating asymmetries of the twenty one Bbars0 → PV decays by employing the perturbative QCD (PQCD) factorization approach. Besides the full leading-order (LO) contributions, all currently known next-to-leading order (NLO) contributions are taken into account. We found numerically that: (a) the NLO contributions can provide ∼ 40% enhancement to the LO PQCD predictions for B (Bbars0 →K0K bar * 0) and B (Bbars0 →K±K*∓), or a ∼ 37% reduction to B (Bbars0 →π-K*+); and we confirmed that the inclusion of the known NLO contributions can improve significantly the agreement between the theory and those currently available experimental measurements; (b) the total effects on the PQCD predictions for the relevant Bs0 → P transition form factors after the inclusion of the NLO twist-2 and twist-3 contributions is generally small in magnitude: less than 10% enhancement respect to the leading order result; (c) for the "tree" dominated decay Bbars0 →K+ρ- and the "color-suppressed-tree" decay Bbars0 →π0K*0, the big difference between the PQCD predictions for their branching ratios are induced by different topological structure and by interference effects among the decay amplitude AT,C and AP: constructive for the first decay but destructive for the second one; and (d) for Bbars0 → V (η ,η‧) decays, the complex pattern of the PQCD predictions for their branching ratios can be understood by rather different topological structures and the interference effects between the decay amplitude A (Vηq) and A (Vηs) due to the η-η‧ mixing.

Mixing zone and drinking water intake dilution factor and wastewater generation distributions to enable probabilistic assessment of down-the-drain consumer product chemicals in the U.S.

PubMed

Kapo, Katherine E; McDonough, Kathleen; Federle, Thomas; Dyer, Scott; Vamshi, Raghu

2015-06-15

Environmental exposure and associated ecological risk related to down-the-drain chemicals discharged by municipal wastewater treatment plants (WWTPs) are strongly influenced by in-stream dilution of receiving waters which varies by geography, flow conditions and upstream wastewater inputs. The iSTREEM® model (American Cleaning Institute, Washington D.C.) was utilized to determine probabilistic distributions for no decay and decay-based dilution factors in mean annual and low (7Q10) flow conditions. The dilution factors derived in this study are "combined" dilution factors which account for both hydrologic dilution and cumulative upstream effluent contributions that will differ depending on the rate of in-stream decay due to biodegradation, volatilization, sorption, etc. for the chemical being evaluated. The median dilution factors estimated in this study (based on various in-stream decay rates from zero decay to a 1h half-life) for WWTP mixing zones dominated by domestic wastewater flow ranged from 132 to 609 at mean flow and 5 to 25 at low flow, while median dilution factors at drinking water intakes (mean flow) ranged from 146 to 2×10(7) depending on the in-stream decay rate. WWTPs within the iSTREEM® model were used to generate a distribution of per capita wastewater generated in the U.S. The dilution factor and per capita wastewater generation distributions developed by this work can be used to conduct probabilistic exposure assessments for down-the-drain chemicals in influent wastewater, wastewater treatment plant mixing zones and at drinking water intakes in the conterminous U.S. In addition, evaluation of types and abundance of U.S. wastewater treatment processes provided insight into treatment trends and the flow volume treated by each type of process. Moreover, removal efficiencies of chemicals can differ by treatment type. Hence, the availability of distributions for per capita wastewater production, treatment type, and dilution factors at a national level provides a series of practical and powerful tools for building probabilistic exposure models. Copyright © 2015 Elsevier B.V. All rights reserved.

Topical applications of resonance internal conversion in laser produced plasma

NASA Astrophysics Data System (ADS)

Karpeshin, F. F.

2007-04-01

Physical aspects of resonance effects arising in plasma due to interactions of nuclei with the electrons are considered. Among them are resonance conversion (TEEN) and the reverse process of NEET. These processes are of great importance for pumping the excited nuclear states (isomers) and for accelerating their decay. Experiment is discussed on studying the unique 3.5-eV 229m Th nuclide.

Prediction of the thermal imaging minimum resolvable (circle) temperature difference with neural network application.

PubMed

Fang, Yi-Chin; Wu, Bo-Wen

2008-12-01

Thermal imaging is an important technology in both national defense and the private sector. An advantage of thermal imaging is its ability to be deployed while fully engaged in duties, not limited by weather or the brightness of indoor or outdoor conditions. However, in an outdoor environment, many factors, including atmospheric decay, target shape, great distance, fog, temperature out of range and diffraction limits can lead to bad image formation, which directly affects the accuracy of object recognition. The visual characteristics of the human eye mean that it has a much better capacity for picture recognition under normal conditions than artificial intelligence does. However, conditions of interference significantly reduce this capacity for picture recognition for instance, fatigue impairs human eyesight. Hence, psychological and physiological factors can affect the result when the human eye is adopted to measure MRTD (minimum resolvable temperature difference) and MRCTD (minimum resolvable circle temperature difference). This study explores thermal imaging recognition, and presents a method for effectively choosing the characteristic values and processing the images fully. Neural network technology is successfully applied to recognize thermal imaging and predict MRTD and MRCTD (Appendix A), exceeding thermal imaging recognition under fatigue and the limits of the human eye.

Catalysis of copper corrosion products on chlorine decay and HAA formation in simulated distribution systems.

PubMed

Zhang, Hong; Andrews, Susan A

2012-05-15

This study investigated the effect of copper corrosion products, including Cu(II), Cu(2)O, CuO and Cu(2)(OH)(2)CO(3), on chlorine degradation, HAA formation, and HAA speciation under controlled experimental conditions. Chlorine decay and HAA formation were significantly enhanced in the presence of copper with the extent of copper catalysis being affected by the solution pH and the concentration of copper corrosion products. Accelerated chlorine decay and increased HAA formation were observed at pH 8.6 in the presence of 1.0 mg/L Cu(II) compared with that observed at pH 6.6 and pH 7.6. Further investigation of chlorine decay in the presence of both Suwannee River NOM and Cu(II) indicated that an increased reactivity of NOM with dissolved and/or solid surface-associated Cu(II), rather than chlorine auto-decomposition, was a primary reason for the observed rapid chlorine decay. Copper corrosion solids [Cu(2)O, CuO, Cu(2)(OH)(2)CO(3)] exhibited catalytic effects on both chlorine decay and HAA formation. Contrary to the results observed when in the absence of copper corrosion products, DCAA formation was consistently predominant over other HAA species in the presence of copper corrosion products, especially at neutral and high pH. This study improves the understanding for water utilities and households regarding chlorine residuals and HAA concentrations in distribution systems, in particular once the water reaches domestic plumbing where copper is widely used. Copyright © 2012 Elsevier Ltd. All rights reserved.

An effective method to accurately calculate the phase space factors for β - β - decay

DOE Office of Scientific and Technical Information (OSTI.GOV)

Neacsu, Andrei; Horoi, Mihai

2016-01-01

Accurate calculations of the electron phase space factors are necessary for reliable predictions of double-beta decay rates and for the analysis of the associated electron angular and energy distributions. Here, we present an effective method to calculate these phase space factors that takes into account the distorted Coulomb field of the daughter nucleus, yet it allows one to easily calculate the phase space factors with good accuracy relative to the most exact methods available in the recent literature.

Wood decay and the cleanup crew

Treesearch

Kevin T. Smith; Jessie A. Glaeser

2017-01-01

Arborists are encouraged to recognize the wood-decay process as an important factor in tree health and public safety. Technical experts who develop training materials to recognize wood-decay processes in living trees are frequently forest pathologists. Much of the history of forest pathology was to support production of sound, high-quality timber. That heritage is...

The Use of Recombinant Human Platelet-Derived Growth Factor for Maxillary Sinus Augmentation.

PubMed

Kubota, Atsushi; Sarmiento, Hector; Alqahtani, Mohammed Saad; Llobell, Arturo; Fiorellini, Joseph P

The maxillary sinus augmentation procedure has become a predictable treatment to regenerate bone for implant placement. The purpose of this study was to evaluate the effect of recombinant human platelet-derived growth factor BB (rhPDGF-BB) combined with a deproteinized cancellous bovine bone graft for sinus augmentation. The lateral window approach was used for maxillary sinuses with minimal residual bone. After a healing period of 4 months, dental implants were placed and then restored following a 2-month osseointegration period. The result demonstrated increased bone height and ISQ values and a 100% survival rate. This study indicates that the addition of rhPDGF-BB to deproteinized cancellous bovine bone accelerated the healing period in maxillary sinuses with minimal native bone.

Where do those remains come from?

PubMed

Nociarová, Dominika; Adserias, M Jose; Malgosa, Assumpció; Galtés, Ignasi

2014-12-01

Part of the study of skeletal remains or corpses in advance decay located in the field involves determining their origin. They may be the result of criminal activity, accident, unearthed because of erosion, or they may also have originated from a cemetery. The discovery site, condition of the remains, and the associated artifacts, are factors that could be helpful for the forensic anthropologist to identify the origin of the remains. In order to contribute to this recognition, an analysis was made of the exhumations of 168 unclaimed human remains from the cemetery of Terrassa (Catalonia, Spain). This investigation presents a description of artifacts and conditions of remains that could indicate that the human remains may have originated from a cemetery. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

Theory of optimal balance predicts and explains the amplitude and decay time of synaptic inhibition

PubMed Central

Kim, Jaekyung K.; Fiorillo, Christopher D.

2017-01-01

Synaptic inhibition counterbalances excitation, but it is not known what constitutes optimal inhibition. We previously proposed that perfect balance is achieved when the peak of an excitatory postsynaptic potential (EPSP) is exactly at spike threshold, so that the slightest variation in excitation determines whether a spike is generated. Using simulations, we show that the optimal inhibitory postsynaptic conductance (IPSG) increases in amplitude and decay rate as synaptic excitation increases from 1 to 800 Hz. As further proposed by theory, we show that optimal IPSG parameters can be learned through anti-Hebbian rules. Finally, we compare our theoretical optima to published experimental data from 21 types of neurons, in which rates of synaptic excitation and IPSG decay times vary by factors of about 100 (5–600 Hz) and 50 (1–50 ms), respectively. From an infinite range of possible decay times, theory predicted experimental decay times within less than a factor of 2. Across a distinct set of 15 types of neuron recorded in vivo, theory predicted the amplitude of synaptic inhibition within a factor of 1.7. Thus, the theory can explain biophysical quantities from first principles. PMID:28281523

Theory of optimal balance predicts and explains the amplitude and decay time of synaptic inhibition

NASA Astrophysics Data System (ADS)

Kim, Jaekyung K.; Fiorillo, Christopher D.

2017-03-01

Synaptic inhibition counterbalances excitation, but it is not known what constitutes optimal inhibition. We previously proposed that perfect balance is achieved when the peak of an excitatory postsynaptic potential (EPSP) is exactly at spike threshold, so that the slightest variation in excitation determines whether a spike is generated. Using simulations, we show that the optimal inhibitory postsynaptic conductance (IPSG) increases in amplitude and decay rate as synaptic excitation increases from 1 to 800 Hz. As further proposed by theory, we show that optimal IPSG parameters can be learned through anti-Hebbian rules. Finally, we compare our theoretical optima to published experimental data from 21 types of neurons, in which rates of synaptic excitation and IPSG decay times vary by factors of about 100 (5-600 Hz) and 50 (1-50 ms), respectively. From an infinite range of possible decay times, theory predicted experimental decay times within less than a factor of 2. Across a distinct set of 15 types of neuron recorded in vivo, theory predicted the amplitude of synaptic inhibition within a factor of 1.7. Thus, the theory can explain biophysical quantities from first principles.

Cell wall-degrading enzymes of Didymella bryoniae in relation to fungal growth and virulence in cantaloupe fruit

PubMed Central

Zhang, J.; Bruton, B. D.; Biles, C. L.

2014-01-01

Didymella bryoniae is an important pathogen of cucurbits worldwide. Virulence factors of D. bryoniae were investigated in regard to fungal growth and the production of cell wall-degrading enzymes, polygalacturonase (PG), pectate lyase (PL), pectin lyase (PNL), β-galactosidase (β-Gal) and cellulase (Cx). Virulence levels of five D. bryoniae isolates were determined by the severity of inoculated cantaloupe fruit decay. The highly virulent isolates had more mycelial growth than the moderately virulent isolates in different media. PG activities produced by the highly virulent isolates in shake cultures and in decayed fruit were greater than those of the moderately virulent isolates. PNL, but not PL, in decayed fruit was higher with the highly virulent isolates compared to the moderately virulent ones. The highly virulent isolates showed higher Cx activity than the moderately virulent ones in decayed fruit and in fruit tissue shake culture. β-Gal activities of the highly virulent isolates in pectin shake culture and in decayed fruit were greater than those of the two moderately virulent isolates although fruit also produced β-Gal. Protein analysis showed two fungal β-Gal isozymes in decayed fruit compared to those of healthy fruit. Correlation analysis indicated that the activities of PG, PNL, β-Gal and Cx in cultures and in decayed fruit positively correlated with fungal growth and fruit decay severity. The results of this study suggest that PG, PNL, β-Gal, and Cx appear to be virulence factors of D. bryoniae in cantaloupe decay with PG and β-Gal as the most predominant fruit decay enzymes. PMID:25364138

Establishing the Biodynamics Data Resource (BDR): Human Volunteer Impact Acceleration Research Data in the BDR

DTIC Science & Technology

2009-10-01

accelerations (+Z) were applied to HRVs in the supine position to mimic the acceleration of an ejection seat , while runs simulating aircraft crashes were...Naval Biodynamics Laboratory, 1985). The vertical testing provided a more authentic ejection seat simulation than was achievable using axial...impact acceleration exposures with hundreds of human research volunteers. The resulting volumes of kinematic and physiological data serve as a

Genome-Wide Identification of Regulatory Sequences Undergoing Accelerated Evolution in the Human Genome

PubMed Central

Dong, Xinran; Wang, Xiao; Zhang, Feng; Tian, Weidong

2016-01-01

Accelerated evolution of regulatory sequence can alter the expression pattern of target genes, and cause phenotypic changes. In this study, we used DNase I hypersensitive sites (DHSs) to annotate putative regulatory sequences in the human genome, and conducted a genome-wide analysis of the effects of accelerated evolution on regulatory sequences. Working under the assumption that local ancient repeat elements of DHSs are under neutral evolution, we discovered that ∼0.44% of DHSs are under accelerated evolution (ace-DHSs). We found that ace-DHSs tend to be more active than background DHSs, and are strongly associated with epigenetic marks of active transcription. The target genes of ace-DHSs are significantly enriched in neuron-related functions, and their expression levels are positively selected in the human brain. Thus, these lines of evidences strongly suggest that accelerated evolution on regulatory sequences plays important role in the evolution of human-specific phenotypes. PMID:27401230

Analysis of four-body decay of D meson

NASA Astrophysics Data System (ADS)

Estabar, T.; Mehraban, H.

2017-01-01

The aim of this work is to provide a phenomenological analysis of the contribution of D0 meson to f0(980)π+π-(f 0(980) → π+π-), K+K-K¯∗(982)0(K¯∗(982)0 → π+K-) and ϕ(π+π-) S-wave(ϕ → K+K-) quasi-three-body decays. Such that the analysis of mentioned four-body decays is summarized into three-body decay and several channels are observed. Based on the factorization approach, hadronic three-body decays receive both resonant and nonresonant contributions. We compute both contributions of three-body decays. As, there are tree, penguin, emission, and emission annihilation diagrams for these decay modes. Our theoretical model for D0 → ϕ(ππ) S-wave decay is based on the QCD factorization to quasi-two body followed by S-wave. This model for this decay following experimental information which demonstrated two pion interaction in the S-wave is introduced by the scalar resonance. The theoretical values are (1.82 ± 0.24) × 10-4, (4.46 ± 0.41) × 10-5 and (1.1 ± 0.18) × 10-4, while the experimental results of them are (1.8 ± 0.5) × 10-4, (4.4 ± 1.7) × 10-5 and (2.5 ± 0.33) × 10-4, respectively. Comparing computation analysis values with experimental values show that our results are in agreement with them.

D → Klv semileptonic decay using lattice QCD with HISQ at physical pion masses

NASA Astrophysics Data System (ADS)

Chakraborty, Bipasha; Davies, Christine; Koponen, Jonna; Lepage, G. Peter

2018-03-01

he quark flavor sector of the Standard Model is a fertile ground to look for new physics effects through a unitarity test of the Cabbibo-Kobayashi-Maskawa (CKM) matrix. We present a lattice QCD calculation of the scalar and the vector form factors (over a large q2 region including q2 = 0) associated with the D→ Klv semi-leptonic decay. This calculation will then allow us to determine the central CKM matrix element, Vcs in the Standard Model, by comparing the lattice QCD results for the form factors and the experimental decay rate. This form factor calculation has been performed on the Nf = 2 + 1 + 1 MILC HISQ ensembles with the physical light quark masses.

Anthropometry: Basic Studies ad Applications. Volume 1. 1964-1975

DTIC Science & Technology

1977-09-01

Human factors engineering. Cadavers, Moments of inertia, Mass, Aerospace medicine, Tables(Data), Responses IDENTIFIERS: DOT/5A, NTlSDOTHTS PB-241...muscles; head/neck response to low-level acceleration, voluntary isometric muscle force in the lateral direction; and three-dimensional range of motion...Prices: PC$7.50/MFS2.25 \\ 77 22 Whole Body Response Research Program Michigan Univ., Ann Arbor. Dept* of Biomechanics.*General Motors

Accelerating cocaine metabolism as an approach to the treatment of cocaine abuse and toxicity

PubMed Central

Schindler, Charles W; Goldberg, Steven R

2012-01-01

One pharmacokinetic approach to the treatment of cocaine abuse and toxicity involves the development of compounds that can be safely administered to humans and that accelerate the metabolism of cocaine to inactive components. Catalytic antibodies have been developed and shown to accelerate cocaine metabolism, but their catalytic efficiency for cocaine is relatively low. Mutations of human butyrylcholinesterase and a bacterial cocaine esterase found in the soil of coca plants have also been developed. These compounds accelerate cocaine metabolism and antagonize the behavioral and toxic effects of cocaine in animal models. Of these two approaches, the human butyrylcholinesterase mutants show the most immediate promise as they would not be expected to evoke an immune response in humans. PMID:22300096

Accelerator-based neutrino oscillation experiments

DOE Office of Scientific and Technical Information (OSTI.GOV)

Harris, Deborah A.; /Fermilab

2007-12-01

Neutrino oscillations were first discovered by experiments looking at neutrinos coming from extra-terrestrial sources, namely the sun and the atmosphere, but we will be depending on earth-based sources to take many of the next steps in this field. This article describes what has been learned so far from accelerator-based neutrino oscillation experiments, and then describe very generally what the next accelerator-based steps are. In section 2 the article discusses how one uses an accelerator to make a neutrino beam, in particular, one made from decays in flight of charged pions. There are several different neutrino detection methods currently in use,more » or under development. In section 3 these are presented, with a description of the general concept, an example of such a detector, and then a brief discussion of the outstanding issues associated with this detection technique. Finally, section 4 describes how the measurements of oscillation probabilities are made. This includes a description of the near detector technique and how it can be used to make the most precise measurements of neutrino oscillations.« less

Impulsive And Long Duration High-Energy Gamma-Ray Emission From The Very Bright 2012 March 7 Solar Flares

DOE PAGES

Ajello, M.

2014-06-10

The Fermi Large Area Telescope (LAT) observed two bright X-class solar ares on 2012 March 7, and detected gamma-rays up to 4 GeV. We detected gamma-rays both during the impulsive and temporally-extended emission phases, with emission above 100 MeV lasting for approximately 20 hours. Accurate localization of the gamma-ray production site(s) coincide with the solar active region from which X-ray emissions associated with these ares originated. Our analysis of the > 100 MeV gamma-ray emission shows a relatively rapid monotonic decrease in flux during the first hour of the impulsive phase, and a much slower, almost monotonic decrease in fluxmore » for the next 20 hours. The spectra can be adequately described by a power law with a high energy exponential cutoff, or as resulting from the decay of neutral pions produced by accelerated protons and ions with an isotropic power-law energy distribution. The required proton spectrum has a number index 3, with minor variations during the impulsive phase, while during the temporally extended phase the spectrum softens monotonically, starting with index 4. The > 30 MeV proton flux and spectra observed near the Earth by the GOES satellites also show a monotonic flux decrease and spectral softening during the extended phase, but with a harder spectrum, with index 3. Based on the Fermi-LAT and GOES observations of the flux and spectral evolution of these bright ares, we explore the relative merits of prompt and continuous acceleration scenarios, hadronic and leptonic emission processes, and acceleration at the solar corona by the fast Coronal Mass Ejections (CME) as explanations for the observations. We conclude that the most likely scenario is continuous acceleration of protons in the solar corona which penetrate the lower solar atmosphere and produce pions that decay into gamma-rays.« less

Impulsive And Long Duration High-Energy Gamma-Ray Emission From The Very Bright 2012 March 7 Solar Flares

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ajello, M.

The Fermi Large Area Telescope (LAT) observed two bright X-class solar ares on 2012 March 7, and detected gamma-rays up to 4 GeV. We detected gamma-rays both during the impulsive and temporally-extended emission phases, with emission above 100 MeV lasting for approximately 20 hours. Accurate localization of the gamma-ray production site(s) coincide with the solar active region from which X-ray emissions associated with these ares originated. Our analysis of the > 100 MeV gamma-ray emission shows a relatively rapid monotonic decrease in flux during the first hour of the impulsive phase, and a much slower, almost monotonic decrease in fluxmore » for the next 20 hours. The spectra can be adequately described by a power law with a high energy exponential cutoff, or as resulting from the decay of neutral pions produced by accelerated protons and ions with an isotropic power-law energy distribution. The required proton spectrum has a number index 3, with minor variations during the impulsive phase, while during the temporally extended phase the spectrum softens monotonically, starting with index 4. The > 30 MeV proton flux and spectra observed near the Earth by the GOES satellites also show a monotonic flux decrease and spectral softening during the extended phase, but with a harder spectrum, with index 3. Based on the Fermi-LAT and GOES observations of the flux and spectral evolution of these bright ares, we explore the relative merits of prompt and continuous acceleration scenarios, hadronic and leptonic emission processes, and acceleration at the solar corona by the fast Coronal Mass Ejections (CME) as explanations for the observations. We conclude that the most likely scenario is continuous acceleration of protons in the solar corona which penetrate the lower solar atmosphere and produce pions that decay into gamma-rays.« less

SOLAR INTERACTING PROTONS VERSUS INTERPLANETARY PROTONS IN THE CORE PLUS HALO MODEL OF DIFFUSIVE SHOCK ACCELERATION AND STOCHASTIC RE-ACCELERATION

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kocharov, L.; Laitinen, T.; Vainio, R.

2015-06-10

With the first observations of solar γ-rays from the decay of pions, the relationship of protons producing ground level enhancements (GLEs) on the Earth to those of similar energies producing the γ-rays on the Sun has been debated. These two populations may be either independent and simply coincident in large flares, or they may be, in fact, the same population stemming from a single accelerating agent and jointly distributed at the Sun and also in space. Assuming the latter, we model a scenario in which particles are accelerated near the Sun in a shock wave with a fraction transported backmore » to the solar surface to radiate, while the remainder is detected at Earth in the form of a GLE. Interplanetary ions versus ions interacting at the Sun are studied for a spherical shock wave propagating in a radial magnetic field through a highly turbulent radial ray (the acceleration core) and surrounding weakly turbulent sector in which the accelerated particles can propagate toward or away from the Sun. The model presented here accounts for both the first-order Fermi acceleration at the shock front and the second-order, stochastic re-acceleration by the turbulence enhanced behind the shock. We find that the re-acceleration is important in generating the γ-radiation and we also find that up to 10% of the particle population can find its way to the Sun as compared to particles escaping to the interplanetary space.« less

Cumulative role of rare and common putative functional genetic variants at NPAS3 in schizophrenia susceptibility.

PubMed

González-Peñas, Javier; Arrojo, Manuel; Paz, Eduardo; Brenlla, Julio; Páramo, Mario; Costas, Javier

2015-10-01

Schizophrenia may be considered a human-specific disorder arisen as a maladaptive by-product of human-specific brain evolution. Therefore, genetic variants involved in susceptibility to schizophrenia may be identified among those genes related to acquisition of human-specific traits. NPAS3, a transcription factor involved in central nervous system development and neurogenesis, seems to be implicated in the evolution of human brain, as it is the human gene with most human-specific accelerated elements (HAEs), i.e., .mammalian conserved regulatory sequences with accelerated evolution in the lineage leading to humans after human-chimpanzee split. We hypothesize that any nucleotide variant at the NPAS3 HAEs may lead to altered susceptibility to schizophrenia. Twenty-one variants at these HAEs detected by the 1000 genomes Project, as well as five additional variants taken from psychiatric genome-wide association studies, were genotyped in 538 schizophrenic patients and 539 controls from Galicia. Analyses at the haplotype level or based on the cumulative role of the variants assuming different susceptibility models did not find any significant association in spite of enough power under several plausible scenarios regarding direction of effect and the specific role of rare and common variants. These results suggest that, contrary to our hypothesis, the special evolution of the NPAS3 HAEs in Homo relaxed the strong constraint on sequence that characterized these regions during mammalian evolution, allowing some sequence changes without any effect on schizophrenia risk. © 2015 Wiley Periodicals, Inc.

Association of hormonal responses and performance of student pilots during acceleration training on the human centrifuge

NASA Astrophysics Data System (ADS)

Wirth, D.; Rohleder, N.; Welsch, H.

2005-08-01

Prediction of student pilots' +Gz tolerance by stress hormone levels would be a useful tool in aviation medicine. The aim of the present study was to analyze the relationship between neuroendocrine parameters with performance during acceleration training on the human centrifuge (HC).We investigated 21 student pilots during self-controlled acceleration training on the HC. Adrenocorticotropic hormone (ACTH), cortisol, epinephrine, and norepinephrine were measured after individual training sessions and at rest. Performance was defined by several characteristics including maximum tolerated acceleration. ACTH and cortisol, were significantly higher 20 minutes after acceleration training compared to the resting condition. Subjects tolerated a maximal acceleration of +6.69 Gz. HPA hormone levels and responses were associated with maximum tolerated acceleration +Gz. These findings support the expectation that acceleration- induced increases in stress hormones may enable the organism to tolerate a higher acceleration and could therefore be used as predictors for acceleration tolerance.

Differential Decay of Human Faecal Bacteroides in Marine and Freshwater

EPA Science Inventory

Gene sequences from Bacteroides and relatives are being considered for the enumeration of aquatic fecal contamination and estimation of public health risk. To interpret these data, it is necessary to understand the decay of molecular and cultivated indicators and pathogens in en...

Empirical evidence for acceleration-dependent amplification factors

USGS Publications Warehouse

Borcherdt, R.D.

2002-01-01

Site-specific amplification factors, Fa and Fv, used in current U.S. building codes decrease with increasing base acceleration level as implied by the Loma Prieta earthquake at 0.1g and extrapolated using numerical models and laboratory results. The Northridge earthquake recordings of 17 January 1994 and subsequent geotechnical data permit empirical estimates of amplification at base acceleration levels up to 0.5g. Distance measures and normalization procedures used to infer amplification ratios from soil-rock pairs in predetermined azimuth-distance bins significantly influence the dependence of amplification estimates on base acceleration. Factors inferred using a hypocentral distance norm do not show a statistically significant dependence on base acceleration. Factors inferred using norms implied by the attenuation functions of Abrahamson and Silva show a statistically significant decrease with increasing base acceleration. The decrease is statistically more significant for stiff clay and sandy soil (site class D) sites than for stiffer sites underlain by gravely soils and soft rock (site class C). The decrease in amplification with increasing base acceleration is more pronounced for the short-period amplification factor, Fa, than for the midperiod factor, Fv.

A Human Factors Evaluation of a Methodology for Pressurized Crew Module Acceptability for Zero-Gravity Ingress of Spacecraft

NASA Technical Reports Server (NTRS)

Sanchez, Merri J.

2000-01-01

This project aimed to develop a methodology for evaluating performance and acceptability characteristics of the pressurized crew module volume suitability for zero-gravity (g) ingress of a spacecraft and to evaluate the operational acceptability of the NASA crew return vehicle (CRV) for zero-g ingress of astronaut crew, volume for crew tasks, and general crew module and seat layout. No standard or methodology has been established for evaluating volume acceptability in human spaceflight vehicles. Volume affects astronauts'ability to ingress and egress the vehicle, and to maneuver in and perform critical operational tasks inside the vehicle. Much research has been conducted on aircraft ingress, egress, and rescue in order to establish military and civil aircraft standards. However, due to the extremely limited number of human-rated spacecraft, this topic has been un-addressed. The NASA CRV was used for this study. The prototype vehicle can return a 7-member crew from the International Space Station in an emergency. The vehicle's internal arrangement must be designed to facilitate rapid zero-g ingress, zero-g maneuverability, ease of one-g egress and rescue, and ease of operational tasks in multiple acceleration environments. A full-scale crew module mockup was built and outfitted with representative adjustable seats, crew equipment, and a volumetrically equivalent hatch. Human factors testing was conducted in three acceleration environments using ground-based facilities and the KC-135 aircraft. Performance and acceptability measurements were collected. Data analysis was conducted using analysis of variance and nonparametric techniques.

Experimental observations on the decay of environmental DNA from bighead and silver carps

USGS Publications Warehouse

Lance, Richard F.; Klymus, Katy E.; Richter, Cathy; Guan, Xin; Farrington, Heather L.; Carr, Matthew R.; Thompson, Nathan; Chapman, Duane C.; Baerwaldt, Kelly L.

2017-01-01

Interest in the field of environmental DNA (eDNA) is growing rapidly and eDNA surveys are becoming an important consideration for aquatic resource managers dealing with invasive species. However, in order for eDNA monitoring to mature as a research and management tool, there are several critical knowledge gaps that must be filled. One such gap is the fate of eDNA materials in the aquatic environment. Understanding the environmental factors that influence the decay of eDNA and how these factors impact detection probabilities over time and space could have significant implications for eDNA survey design and data interpretation. Here we experimentally explore decay of eDNA associated with bighead carp (Hypophthalmichthys nobilis) biological waste collected from an aquaculture filtration system and with sperm collected from captive silver carp (H. molitrix), and how decay may be influenced by differing levels of water turbulence, temperature, microbial load, and pH. We found that the decay patterns of eDNA associated with both H. nobilis biological waste and H. molitrix milt significantly fit monophasic exponential decay curves. Secondly, we observed that the highest temperature we tested resulted in a decay half-life as much as 5.5× more rapid than the lowest temperature we tested. When we suppressed microbial loads in eDNA samples, we observed that overall losses of eDNA were reduced by about 2.5×. When we amended eDNA samples with pond water the half-life of eDNA was reduced by about 2.25×, despite relatively little apparent increase in the overall microbial load. This pattern indicated that species constituency of the microbial community, in addition to microbial load, might play a critical role in eDNA degradation. A shift in pH from 6.5 to 8.0 in the samples resulted in a 1.6× reduction in eDNA halflife. Water turbulence in our study had no apparent effect on eDNA decay. When we combined different temperature, pH, and microbial load treatments to create a rapid decay condition and a slow decay condition, and tracked eDNA decay over 91 days, we observed a 5.0× greater loss of eDNA by Day 5 under rapid decay conditions than under slow decay conditions. At the end of the trials, the differences in eDNA loss between the rapid decay and baseline and slow decay conditions were 0.1× and 3.3×, respectively. Our results strongly demonstrate the potential for environmental factors to influence eDNA fate and, thus, the interpretation of eDNA survey results.

Radiation protection considerations along a radioactive ion beam transport line

NASA Astrophysics Data System (ADS)

Sarchiapone, Lucia; Zafiropoulos, Demetre

2016-09-01

The goal of the SPES project is to produce accelerated radioactive ion beams for Physics studies at “Laboratori Nazionali di Legnaro” (INFN, Italy). This accelerator complex is scheduled to be built by 2016 for an effective operation in 2017. Radioactive species are produced in a uranium carbide target, by the interaction of 200 μA of protons at 40 MeV. All of the ionized species in the 1+ state come out of the target (ISOL method), and pass through a Wien filter for a first selection and an HMRS (high mass resolution spectrometer). Then they are transported by an electrostatic beam line toward a charge state breeder (where the 1+ to n+ multi-ionization takes place) before selection and reacceleration at the already existing superconducting linac. The work concerning dose evaluations, activation calculation, and radiation protection constraints related to the transport of the radioactive ion beam (RIB) from the target to the mass separator will be described in this paper. The FLUKA code has been used as tool for those calculations needing Monte Carlo simulations, in particular for the evaluation of the dose rate due to the presence of the radioactive beam in the selection/interaction points. The time evolution of a radionuclide inventory can be computed online with FLUKA for arbitrary irradiation profiles and decay times. The activity evolution is analytically evaluated through the implementation of the Bateman equations. Furthermore, the generation and transport of decay radiation (limited to gamma, beta- and beta+ emissions) is possible, referring to a dedicated database of decay emissions using mostly information obtained from NNDC, sometimes supplemented with other data and checked for consistency. When the use of Monte Carlo simulations was not feasible, the Bateman equations, or possible simplifications, have been used directly.

Photoproduction of $$ \\pi^{0}$$-pairs off protons and off neutrons

DOE PAGES

Dieterle, M.; Oberle, M.; Ahrens, J.; ...

2015-11-04

Total cross sections, angular distributions, and invariant-mass distributions have been measured for the photoproduction of π 0π 0 pairs off free protons and off nucleons bound in the deuteron. The experiments were performed at the MAMI accelerator facility in Mainz using the Glasgow photon tagging spectrometer and the Crystal Ball/TAPS detector. The accelerator delivered electron beams of 1508 and 1557MeV, which produced bremsstrahlung in thin radiator foils. The tagged photon beam covered energies up to 1400MeV. The data from the free proton target are in good agreement with previous measurements and were only used to test the analysis procedures. Themore » results for differential cross sections (angular distributions and invariant-mass distributions) for free and quasi-free protons are almost identical in shape, but differ in absolute magnitude up to 15%. Thus, moderate final-state interaction effects are present. The data for quasi-free neutrons are similar to the proton data in the second resonance region (final-state invariant masses up to ≈1550 MeV), where both reactions are dominated by the N(1520)3/2 –→Δ(1232)3/2 +π decay. At higher energies, angular and invariant-mass distributions are different. A simple analysis of the shapes of the invariant-mass distributions in the third resonance region is consistent with strong contributions of an N*→Nσ decay for the proton, while the reaction is dominated by a sequential decay via a Δπ intermediate state for the neutron. Here, the data are compared to predictions from the Two-Pion-MAID model and the Bonn-Gatchina coupled-channel analysis.« less

Multilineage hematopoietic recovery by a single injection of pegylated recombinant human megakaryocyte growth and development factor in myelosuppressed mice.

PubMed

Shibuya, K; Akahori, H; Takahashi, K; Tahara, E; Kato, T; Miyazaki, H

1998-01-01

Previous studies have shown that daily multiple administration of pegylated recombinant human megakaryocyte growth and development factor (PEG-rHuMGDF) markedly stimulates thrombopoiesis and effectively ameliorates thrombocytopenia, and in most cases anemia and neutropenia, in myelosuppressed animals. In this study, we evaluated the effects of a single intravenous injection of PEG-rHuMGDF on hematopoietic recovery after sublethal total-body irradiation in mice. A single injection of PEG-rHuMGDF (1 to 640 microg/kg) 1 hour after irradiation accelerated platelet, red blood cell (RBC), and white blood cell (WBC) recovery in a dose-dependent fashion. In the bone marrow of vehicle-treated mice, megakaryocytic, erythroid, and myeloid progenitors, as well as day 12 colony-forming unit-spleen (CFU-S), were dramatically decreased much earlier than the nadirs of peripheral blood cells, whereas megakaryocytes were modestly decreased. Treatment with PEG-rHuMGDF (80 microg/kg, an optimal dose) 1 hour after irradiation resulted in more rapid recovery of these four hematopoietic progenitors and also significantly facilitated megakaryocyte recovery. In addition, the same PEG-rHuMGDF administration schedule expanded bone marrow cells capable of rescuing lethally irradiated recipient mice. As the interval between irradiation and PEG-rHuMGDF treatment was longer, its effects on hematopoietic recovery were attenuated. In contrast to the effects of PEG-rHuMGDF, a single injection of recombinant human granulocyte colony-stimulating factor (rhG-CSF) 1 hour after irradiation exclusively accelerated WBC recovery, but only to a similar extent as PEG-rHuMGDF (80 microg/kg) treatment even when rhG-CSF doses were escalated to 1,000 microg/kg. This appeared related to different pharmacokinetics of these two factors after a single injection in irradiated mice. The concentrations of PEG-rHuMGDF after injection persisted in the plasma for a longer time compared with rhG-CSF. These results indicate that a single injection of PEG-rHuMGDF at an early time after irradiation is able to effectively improve thrombocytopenia, anemia, and leukopenia with concomitant accelerated recovery of both primitive and committed hematopoietic progenitors in irradiated mice. Our data also show that compared with the rhG-CSF shown to exert multilineage effects on hematopoiesis, PEG-rHuMGDF has more wide-ranging effects on peripheral blood cell recovery.

An RNA decay factor wears a new coat: UPF3B modulates translation termination

PubMed Central

Gao, Zhaofeng; Wilkinson, Miles

2017-01-01

Nonsense-mediated RNA decay (NMD) is a highly conserved and selective RNA turnover pathway that has been subject to intense scrutiny. NMD identifies and degrades subsets of normal RNAs, as well as abnormal mRNAs containing premature termination codons. A core factor in this pathway—UPF3B—is an adaptor protein that serves as an NMD amplifier and an NMD branch-specific factor. UPF3B is encoded by an X-linked gene that when mutated causes intellectual disability and is associated with neurodevelopmental disorders, including schizophrenia and autism. Neu-Yilik et al. now report a new function for UPF3B: it modulates translation termination. Using a fully reconstituted in vitro translation system, they find that UPF3B has two roles in translation termination. First, UPF3B delays translation termination under conditions that mimic premature translation termination. This could drive more efficient RNA decay by allowing more time for the formation of RNA decay-stimulating complexes. Second, UPF3B promotes the dissociation of post-termination ribosomal complexes that lack nascent peptide. This implies that UPF3B could promote ribosome recycling. Importantly, the authors found that UPF3B directly interacts with both RNA and the factors that recognize stop codons—eukaryotic release factors (eRFs)—suggesting that UPF3B serves as a direct regulator of translation termination. In contrast, a NMD factor previously thought to have a central regulatory role in translation termination—the RNA helicase UPF1—was found to indirectly interact with eRFs and appears to act exclusively in post-translation termination events, such as RNA decay, at least in vitro. The finding that an RNA decay-promoting factor, UFP3B, modulates translation termination has many implications. For example, the ability of UPF3B to influence the development and function of the central nervous system may be not only through its ability to degrade specific RNAs but also through its impact on translation termination and subsequent events, such as ribosome recycling. PMID:29333258

Two- and Three-Body Charmless B Decays at BaBar

DOE Office of Scientific and Technical Information (OSTI.GOV)

Stracka, Simone; /Milan U. /INFN, Milan

2012-04-05

We report recent measurements of rare charmless B decays performed by BaBar. The results are based on the final BaBar dataset of 424 fb{sup -1} collected at the PEP-II B-factory based at the SLAC National Accelerator Laboratory. The study of rare B decays is a key ingredient to meet two of the main goals of the B-factories: assessing the validity of the Cabibbo-Kobayashi-Maskawa (CKM) picture of CP-violation by precisely measuring the elements of the Unitarity Triangle (UT), and searching for hints of New Physics (NP), or otherwise constraining NP scenarios, in processes which are suppressed in the Standard Model (SM).more » In loop processes, in particular, NP at some higher energy scale may manifest itself in the low energy effective theory as new couplings, such as those introduced by new very massive virtual particles in the loop. In NP searches hadronic uncertainties can play a major role, expecially for branching fraction measurements. Many theoretical uncertainties cancel in ratios of amplitudes, and most NP probes are therefore of this kind. In the following sections we report recent measurements, performed by the BaBar Collaboration, that are relevant to NP searches in charmless hadronic B decays.« less

Recent results from the NA48 experiment at CERN

NASA Astrophysics Data System (ADS)

Shkarovskiy, Sergey; NA48/2 Collaboration

2017-12-01

The NA48/2 experiment presents a final result of the charged kaon semileptonic decays form factors measurement based on 4.28 million Ke3+/- and 2.91 million K{μ3}+/- selected decays collected in 2004. The result is competetive with other measurements in K{μ3}+/- mode and has a smallest uncertainty for Ke3+/- , that leads to the most precise combined Kl3+/- result and allows to reduce the form factor uncertainty of |VUS |. The NA48/2 experiment at CERN collected a very large sample of charged kaon decays into multiple final states. From this data sample we have reconstructed about 1663 events of the very rare decay K ± → μ ± νe + e - over almost negligible background in the region with m(e + e -) above 140 MeV, which is of great interest in Chiral Perturbation Theory. We present the mee spectrum and a model-independent measurement of the decay rate for this region.

Properties of charmonia in a hot equilibrated medium

DOE Office of Scientific and Technical Information (OSTI.GOV)

Giannuzzi, Floriana; Mannarelli, Massimo

2009-09-01

We investigate the properties of charmonia in a thermal medium, showing that with increasing temperature the decay widths of these mesons behave in a nontrivial way. Our analysis is based on a potential model with interaction potential extracted from thermal lattice QCD calculations of the free-energy of a static quark-antiquark pair. We find that in the crossover region some decay widths are extremely enhanced. In particular, at temperatures T{approx}T{sub c} the decay widths of the J/{psi} that depend on the value of the wave function at the origin are enhanced with respect to the values in vacuum by about amore » factor 2. In the same temperature range the decay width of the process {chi}{sub cJ}{yields}J/{psi}+{gamma} is enhanced by approximately a factor 6 with respect to the value in vacuum. At higher temperatures the charmonia states dissociate and the widths of both decay processes become vanishing small.« less

A dispersive treatment of K ι4 decays

DOE PAGES

Stoffer, Peter; Colangelo, Gilberto; Passemar, Emilie

2017-01-01

K ι4 decays have several features of interest: they allow an accurate measurement of ππ-scattering lengths; the decay is the best source for the determination of some low-energy constants of chiral perturbation theory (χPT); one form factor of the decay is connected to the chiral anomaly. Here, we present the results of our dispersive analysis of K ι4 decays, which provides a resummation of ππ- and Kπ-rescattering effects. The free parameters of the dispersion relation are fitted to the data of the high-statistics experiments E865 and NA48/2. By matching to χPT at NLO and NNLO, we determine the low-energy constantsmore » and L r 1, L r 2, and L r 3. In contrast to a pure chiral treatment, the dispersion relation describes the observed curvature of one of the K ι4 form factors, which we understand as an effect of rescattering beyond NNLO.« less

Hearings Before the Select Committee on Nutrition and Human Needs of the United States Senate, Ninety-Third Congress, First Session. Nutrition Education--1973. Part 6--Phosphate Research and Dental Decay. Hearings Held Washington, D.C., April 16, 1973.

ERIC Educational Resources Information Center

Congress of the U.S., Washington, DC. Senate Select Committee on Nutrition and Human Needs.

These hearings before the Select Committee on Nutrition and Human Needs of the United States Senate include testimony on the subject of research into the use of phosphates to prevent dental decay. The purpose of the hearing was to explore certain dental health questions raised during the committee's recent hearings on the Television Advertising of…

Quasi-Periodic Pulsations During the Impulsive and Decay Phases of an X-Class Flare

NASA Technical Reports Server (NTRS)

Hays, L. A.; Gallagher, P. T.; Dennis, B. R.; Ireland, J.; Inglis, A. R.; Ryan, D. F.

2016-01-01

Quasi-periodic pulsations (QPPs) are often observed in X-ray emission from solar flares. To date, it is unclear what their physical origins are. Here, we present a multi-instrument investigation of the nature of QPP during the impulsive and decay phases of the X1.0 flare of 2013 October 28. We focus on the character of the fine structure pulsations evident in the soft X-ray (SXR) time derivatives and compare this variability with structure across multiple wavelengths including hard X-ray and microwave emission. We find that during the impulsive phase of the flare, high correlations between pulsations in the thermal and non-thermal emissions are seen. A characteristic timescale of 20 s is observed in all channels and a second timescale of 55 s is observed in the non-thermal emissions. SXR pulsations are seen to persist into the decay phase of this flare, up to 20 minutes after the non-thermal emission has ceased. We find that these decay phase thermal pulsations have very small amplitude and show an increase in characteristic timescale from 40 s up to 70 s. We interpret the bursty nature of the co-existing multi-wavelength QPPs during the impulsive phase in terms of episodic particle acceleration and plasma heating. The persistent thermal decay phase QPPs are most likely connected with compressive magnetohydrodynamic processes in the post-flare loops such as the fast sausage mode or the vertical kink mode.

Measurements of the ^89Y(n,n')^89Y^m reaction cross section using the ASP D-T fusion source

NASA Astrophysics Data System (ADS)

Simons, Andrew; Gardner, Matthew; Williams, Ben; Rubery, Michael

2012-10-01

A programme of measurements of the ^89Y(n,n')^89Y^m reaction cross section has commenced at AWE using the ASP accelerator to impinge deuterons onto tritiated titanium layers mounted on copper discs producing fluxes of approximately 10^11 neutrons per second. The neutrons are generated for up to half an hour and are used to excite Yttrium into its first isomeric state at 909.1 keV which then decays with a half life of 15.7 seconds. Two other high purity foils (of ^27Al and ^63,65Cu) are used as a reference to establish consistency between the isotopes energetic and temporal decay signatures. These foils mainly serve to check the reported total neutron fluence, produced by the accelerator, incident on the targets. The activation foils are extracted from the irradiation position by a pneumatic transfer system in ˜ 7 seconds and are transferred to the counting station in 5 to 30 seconds. Data are taken with a BEGe detector and recorded with both a Canberra Genie analogue system and a Xia Pixie-4 digital system. The results from the first campaigns are presented with a discussion of improvements and future plans.

The NUMEN project @ LNS: Status and perspectives

NASA Astrophysics Data System (ADS)

Cappuzzello, F.; Agodi, C.; Acosta, L.; Auerbach, N.; Bellone, J.; Bijker, R.; Bonanno, D.; Bongiovanni, D.; Borello-Lewin, T.; Boztosun, I.; Branchina, V.; Bussa, M. P.; Calabrese, S.; Calabretta, L.; Calanna, A.; Carbone, D.; Cavallaro, M.; Calvo, D.; Lomelí, E. R. Chávez; Coban, A.; Colonna, M.; D'Agostino, G.; Degeronimo, G.; Delaunay, F.; Deshmukh, N.; de Faria, P. N.; Ferraresi, C.; Ferreira, J. L.; Fisichella, M.; Foti, A.; Finocchiaro, P.; Gallo, G.; Garcia, U.; Giraudo, G.; Greco, V.; Hacisalihoglu, A.; Kotila, J.; Iazzi, F.; Introzzi, R.; Lanzalone, G.; Lavagno, A.; Via, F. La; Lay, J. A.; Lenske, H.; Linares, R.; Litrico, G.; Longhitano, F.; Presti, D. Lo; Lubian, J.; Medina, N.; Mendes, D. R.; Muoio, A.; Oliveira, J. R. B.; Pakou, A.; Pandola, L.; Petrascu, H.; Pinna, F.; Reito, S.; Rifuggiato, D.; Rodrigues, M. R. D.; Russo, A. D.; Russo, G.; Santagati, G.; Santopinto, E.; Sgouros, O.; Solakcı, S. O.; Souliotis, G.; Soukeras, V.; Spatafora, A.; Torresi, D.; Tudisco, S.; Vsevolodovna, R. I. M.; Wheadon, R. J.; Yildirin, A.; Zagatto, V.

2017-10-01

The NUMEN project aims at accessing experimentally driven information on Nuclear Matrix Elements (NME) involved in the half-life of the neutrinoless double beta decay (0νββ), by high-accuracy measurements of the cross sections of Heavy Ion (HI) induced Double Charge Exchange (DCE) reactions. Particular attention is given to the (18O,18Ne) and (20Ne,20O) reactions as tools for β+β+ and β-β-decays, respectively. First evidence about the possibility to get quantitative information about NME from experiments is found for both kind of reactions. In the experiments, performed at INFN - Laboratory Nazionali del Sud (LNS) in Catania, the beams are accelerated by the Superconducting Cyclotron (CS) and the reaction products are detected the MAGNEX magnetic spectrometer. The measured cross sections are challengingly low, limiting the present exploration to few selected isotopes of interest in the context of typically low-yield experimental runs. A major upgrade of the LNS facility is foreseen in order to increase the experimental yield of at least two orders of magnitude, thus making feasible a systematic study of all the cases of interest. Frontiers technologies are going to be developed, to this purpose, for the accelerator and the detection systems. In parallel, advanced theoretical models will be developed in order to extract the nuclear structure information from the measured cross sections.

Tissue characterization by time-resolved fluorescence spectroscopy of endogenous and exogenous fluorochromes: apparatus design and preliminary results

NASA Astrophysics Data System (ADS)

Glanzmann, Thomas M.; Ballini, Jean-Pierre; Jichlinski, Patrice; van den Bergh, Hubert; Wagnieres, Georges A.

1996-12-01

The biomedical use of an optical fiber-based spectro- temporal fluorometer that can endoscopically record the fluorescence decay of an entire spectrum without scanning is presented. The detector consists of a streak camera coupled to a spectrograph. A mode-locked argon ion pumped dye laser or a nitrogen laser-pumped dye laser are used as pulsed excitation light sources. We measured the fluorescence decays of endogenous fluorophores and of ALA-induced- protoporphyrin IX(PPIX) in an excised human bladder with a carcinoma in situ (CIS). Each autofluorescence decay can be decomposed in at least three exponential components for all tissue samples investigated if the excitation is at 425 nm. The decays of the autofluorescence of all normal sites of the human bladder are similar and they differ significantly from the decays measured on the CIS and the necrotic tissue. The fluorescence of the ALA-induced PPIX in the bladder is monoexponential with a lifetime of 15 (plus or minus 1) ns and this fluorescence lifetime does not change significantly between the normal urothelium and the CIS. A photoproduct of ALA-PPIX with a fluorescence maximum at 670 nm and a lifetime of 8 (plus or minus 1) ns was observed. The measurement of the decay of the autofluorescence allowed to correctly identify a normal tissue site that was classified as abnormal by the measurement of the ALA-PPIX fluorescence intensity.

Accelerated ageing and renal dysfunction links lower socioeconomic status and dietary phosphate intake.

PubMed

McClelland, Ruth; Christensen, Kelly; Mohammed, Suhaib; McGuinness, Dagmara; Cooney, Josephine; Bakshi, Andisheh; Demou, Evangelia; MacDonald, Ewan; Caslake, Muriel; Stenvinkel, Peter; Shiels, Paul G

2016-05-01

We have sought to explore the impact of dietary Pi intake on human age related health in the pSoBid cohort (n=666) to explain the disparity between health and deprivation status in this cohort. As hyperphosphataemia is a driver of accelerated ageing in rodent models of progeria we tested whether variation in Pi levels in man associate with measures of biological ageing and health. We observed significant relationships between serum Pi levels and markers of biological age (telomere length (p=0.040) and DNA methylation content (p=0.028), gender and chronological age (p=0.032). When analyses were adjusted for socio-economic status and nutritional factors, associations were observed between accelerated biological ageing (telomere length, genomic methylation content) and dietary derived Pi levels among the most deprived males, directly related to the frequency of red meat consumption. Accelerated ageing is associated with high serum Pi levels and frequency of red meat consumption. Our data provide evidence for a mechanistic link between high intake of Pi and age-related morbidities tied to socio-economic status.

Cleaning techniques for intense ion beam sources

DOE Office of Scientific and Technical Information (OSTI.GOV)

Menge, P.R.; Cuneo, M.E.; Bailey, J.E.

Generation of high power lithium ion beams on the SABRE (1TW) and PBFA-X (20 TW) accelerators have been limited by the parallel acceleration of contaminant ions. during the beam pulse lithium is replaced by protons and carbon ions. This replacement is accompanied by rapid impedance decay of the diode. The contaminant hydrogen and carbon is believed to originate from impurity molecules on the surface and in the bulk of the lithium ion source and its substrate material. Cleaning techniques designed to remove hydrocarbons from the ion source have been employed with some success in test stand experiments and on SABRE.more » The test stand experiments have shown that a lithium fluoride (LiF) ion source film can accrue dozens of hydrocarbon monolayers on its surface while sitting in vacuum. Application of 13.5 MHz RF discharge cleaning with 90% Ar/10% O{sub 2} can significantly reduce the surface hydrocarbon layers on the LiF film. On SABRE, combinations of RF discharge cleaning, anode heating, layering gold between the source film (LiF) and its substrate, and cryogenic cathode cooling produced an increase by a factor of 1.5--2 in the quantity of high energy lithium in the ion beam. A corresponding decrease in protons and carbon ions was also observed. Cleaning experiments on PBFA-X are underway. New designs of contamination resistant films and Li ion sources are currently being investigated.« less

Dietary phosphorus burden increases cariogenesis independent of vitamin D uptake.

PubMed

Goodson, J Max; Shi, Ping; Mumena, Chrispinus H; Haq, Afrozul; Razzaque, Mohammed S

2017-03-01

An association between excessive sugar consumption and dental decay, particularly in children, has been well-established. In this study we have analyzed whether consumption of phosphorus, an important ingredient of sugary drinks, has any association with the evolvement of dental decay. Food consumption, gingival redness and dental decay were evaluated in a total of 8,317 children with the mean age of 9.99+0.68 years with a strong gender bias (p<0.0005); boys being more affected than girls. Our results showed a significant association (p=0.044) between dental decay and calorie-adjusted sugar intake. Presence of gingival inflammation also correlated (p=0.008) with the formation of dental decay. In addition, decayed teeth were positively associated with increased salivary levels of adiponectin (p=0.0002) and matrix degrading MMP-9 (p=0.015), while negatively associated with salivary levels of the vascular endothelial growth factor (VEGF; p=0.008). More importantly, we found a statistically significant correlation (p=0.0008) between calorie-adjusted dietary phosphorus intake and occurrence of dental decay. Our analyzed results also showed a significantly high percentage of dental decay in children who consumed a diet, low in sugar but high in phosphorus (6.58%, n=661), compared to those who consumed a low sugar and low phosphorus containing diet (5.02%, n=413). Finally, we did not find any significant association between vitamin D uptake and the genesis of dental decay. From these results, we concluded that both high sugar and high phosphate consumption can influence evolvement of dental decay, and that, a healthier diet could be achieved by reducing consumption of dental cariogenic dietary factors, sugar and phosphate. Copyright © 2016 Elsevier Ltd. All rights reserved.

A dynamic evolution model of human opinion as affected by advertising

NASA Astrophysics Data System (ADS)

Luo, Gui-Xun; Liu, Yun; Zeng, Qing-An; Diao, Su-Meng; Xiong, Fei

2014-11-01

We propose a new model to investigate the dynamics of human opinion as affected by advertising, based on the main idea of the CODA model and taking into account two practical factors: one is that the marginal influence of an additional friend will decrease with an increasing number of friends; the other is the decline of memory over time. Simulations show several significant conclusions for both advertising agencies and the general public. A small difference of advertising’s influence on individuals or advertising coverage will result in significantly different advertising effectiveness within a certain interval of value. Compared to the value of advertising’s influence on individuals, the advertising coverage plays a more important role due to the exponential decay of memory. Meanwhile, some of the obtained results are in accordance with people’s daily cognition about advertising. The real key factor in determining the success of advertising is the intensity of exchanging opinions, and people’s external actions always follow their internal opinions. Negative opinions also play an important role.

Some properties of human neuronal α7 nicotinic acetylcholine receptors fused to the green fluorescent protein

PubMed Central

Palma, Eleonora; Mileo, Anna M.; Martínez-Torres, Ataúlfo; Eusebi, Fabrizio; Miledi, Ricardo

2002-01-01

The functional properties and cellular localization of the human neuronal α7 nicotinic acetylcholine (AcCho) receptor (α7 AcChoR) and its L248T mutated (mut) form were investigated by expressing them alone or as gene fusions with the enhanced version of the green fluorescent protein (GFP). Xenopus oocytes injected with wild-type (wt), mutα7, or the chimeric subunit cDNAs expressed receptors that gated membrane currents when exposed to AcCho. As already known, AcCho currents generated by wtα7 receptors decay much faster than those elicited by the mutα7 receptors. Unexpectedly, the fusion of GFP to the wt and mutated α7 receptors led to opposite results: the AcCho-current decay of the wt receptors became slower, whereas that of the mutated receptors was accelerated. Furthermore, repetitive applications of AcCho led to a considerable “run-down” of the AcCho currents generated by mutα7-GFP receptors, whereas those of the wtα7-GFP receptors remained stable or increased in amplitude. The AcCho-current run-down of mutα7-GFP oocytes was accompanied by a marked decrease of α-bungarotoxin binding activity. Fluorescence, caused by the chimeric receptors expressed, was seen over the whole oocyte surface but was more intense and abundant in the animal hemisphere, whereas it was much weaker in the vegetal hemisphere. We conclude that fusion of GFP to wtα7 and mutα7 receptors provides powerful tools to study the distribution and function of α7 receptors. We also conclude that fused genes do not necessarily recapitulate all of the properties of the original receptors. This fact must be borne close in mind whenever reporter genes are attached to proteins. PMID:11891308

Memory Interference as a Determinant of Language Comprehension

PubMed Central

Van Dyke, Julie A.; Johns, Clinton L.

2012-01-01

The parameters of the human memory system constrain the operation of language comprehension processes. In the memory literature, both decay and interference have been proposed as causes of forgetting; however, while there is a long history of research establishing the nature of interference effects in memory, the effects of decay are much more poorly supported. Nevertheless, research investigating the limitations of the human sentence processing mechanism typically focus on decay-based explanations, emphasizing the role of capacity, while the role of interference has received comparatively little attention. This paper reviews both accounts of difficulty in language comprehension by drawing direct connections to research in the memory domain. Capacity-based accounts are found to be untenable, diverging substantially from what is known about the operation of the human memory system. In contrast, recent research investigating comprehension difficulty using a retrieval-interference paradigm is shown to be wholly consistent with both behavioral and neuropsychological memory phenomena. The implications of adopting a retrieval-interference approach to investigating individual variation in language comprehension are discussed. PMID:22773927

Response repetition biases in human perceptual decisions are explained by activity decay in competitive attractor models

PubMed Central

Bonaiuto, James J; de Berker, Archy; Bestmann, Sven

2016-01-01

Animals and humans have a tendency to repeat recent choices, a phenomenon known as choice hysteresis. The mechanism for this choice bias remains unclear. Using an established, biophysically informed model of a competitive attractor network for decision making, we found that decaying tail activity from the previous trial caused choice hysteresis, especially during difficult trials, and accurately predicted human perceptual choices. In the model, choice variability could be directionally altered through amplification or dampening of post-trial activity decay through simulated depolarizing or hyperpolarizing network stimulation. An analogous intervention using transcranial direct current stimulation (tDCS) over left dorsolateral prefrontal cortex (dlPFC) yielded a close match between model predictions and experimental results: net soma depolarizing currents increased choice hysteresis, while hyperpolarizing currents suppressed it. Residual activity in competitive attractor networks within dlPFC may thus give rise to biases in perceptual choices, which can be directionally controlled through non-invasive brain stimulation. DOI: http://dx.doi.org/10.7554/eLife.20047.001 PMID:28005007

Measurement of |V{sub cb}| using {bar B}{sup 0} {yields} D*{sup +}{ell}{sup -}{bar {nu}}{sub {ell}} Decays

DOE Office of Scientific and Technical Information (OSTI.GOV)

Della Ricca, Giuseppe

A preliminary measurement of |V{sub cb}| and the branching fraction {Beta}({bar B}{sup 0} {yields} D*{sup +}{ell}{sup -}{bar {nu}}{sub {ell}}) has been performed based on a sample of about 55,700 {bar B}{sup 0} {yields} D*{sup +}{ell}{sup -}{bar {nu}}{sub {ell}} decays recorded with the BABAR detector. The decays are identified in the D*{sup +} {yields} D{sup 0}{pi}{sup +} final state, with the D{sup 0} reconstructed in three different decay modes. The differential decay rate is measured as a function of the relativistic boost of the D*{sup +} in the {bar B}{sup 0} rest frame. The value of the differential decay rate atmore » ''zero recoil'', namely the point at which the D*{sup +} is at rest in the {bar B}{sup 0} frame, is predicted in Heavy Quark Effective Theory as a kinematic factor times F(1)|V{sub cb}|, where F is the unique form factor governing the decay. We extrapolate the measured differential decay rate to the zero recoil point and obtain F(1)|V{sub cb}| = (34.03 {+-} 0.24 {+-} 1.31) x 10{sup -3}. Using a theoretical calculation for F(1) we extract |V{sub cb}| = (37.27 {+-} 0.26(stat.) {+-} 1.43(syst.){sub -1.2}{sup +1.5}(theo.)) x 10{sup -3}. From the integrated decay rate we obtain {Beta}({bar B}{sup 0} {yields} D*{sup +}{ell}{sup -}{bar {nu}}{sub {ell}}) = (4.68 {+-} 0.03 {+-} 0.29)%.« less

Quasi Three-Body Decay of D Meson

NASA Astrophysics Data System (ADS)

Estabar, T.; Mehraban, H.

2018-04-01

The aim of this work is to provide a phenomenological analysis of the contribution of D 0 meson to {\\bar{K}}* {(892)}0{π }+{π }-({\\bar{K}}* {(892)}0\\to {π }+{K}-), K ‑ π + ω (ω → π + π ‑ π 0) and K ‑ π + ø (ø(1020) → K+ K ‑) quasi-three-body decays. The analysis of mentioned multi-body decays is such as to factorize into the three-body decay and several channels observed. Hadronic three-body decays receive both resonant and non-resonant contribution. Based on the factorization method, there are tree and emission annihilation diagrams for these decay modes. In the case of D 0 to vector pseudoscalar states appeared in factored terms, the matrix elements of the vector and axial vector currents between the D 0 and PV mesons can be computed by using D *+ pole. Considering the non-resonant and resonant amplitude in our computation, the theoretical values of the branching ratio are (9.78±0.46)×10‑3, (2.74±0.17)×10‑2, and (3.53±0.23)×10‑5, while the experimental results of them are (9.9±2.3)×10‑3, (2.7±0.5)×10‑2, and (4±1.7)×10‑5 respectively. Comparing computational analysis values with experimental values show that our results are in approximately agreement with them.

Cross sections for the γp→K*0Σ+ reaction at Eγ=1.7 3.0 GeV

NASA Astrophysics Data System (ADS)

Hleiqawi, I.; Hicks, K.; Carman, D. S.; Mibe, T.; Niculescu, G.; Tkabladze, A.; Amarian, M.; Ambrozewicz, P.; Anghinolfi, M.; Asryan, G.; Avakian, H.; Bagdasaryan, H.; Baillie, N.; Ball, J. P.; Baltzell, N. A.; Batourine, V.; Battaglieri, M.; Beard, K.; Bedlinskiy, I.; Bellis, M.; Benmouna, N.; Berman, B. L.; Biselli, A. S.; Bouchigny, S.; Boiarinov, S.; Bradford, R.; Branford, D.; Briscoe, W. J.; Brooks, W. K.; Bültmann, S.; Burkert, V. D.; Butuceanu, C.; Calarco, J. R.; Careccia, S. L.; Carnahan, B.; Chen, S.; Cole, P. L.; Collins, P.; Coltharp, P.; Crabb, D.; Crannell, H.; Crede, V.; Cummings, J. P.; Masi, R. De; Vita, R. De; Sanctis, E. De; Degtyarenko, P. V.; Dennis, L.; Deur, A.; Djalali, C.; Dickson, R.; Dodge, G. E.; Donnelly, J.; Doughty, D.; Dugger, M.; Dytman, S.; Dzyubak, O. P.; Egiyan, H.; Egiyan, K. S.; Elouadrhiri, L.; Eugenio, P.; Fedotov, G.; Feldman, G.; Fersch, R.; Feuerbach, R.; Garçon, M.; Gavalian, G.; Gilfoyle, G. P.; Giovanetti, K. L.; Girod, F. X.; Goetz, J. T.; Gonenc, A.; Gothe, R. W.; Griffioen, K. A.; Guidal, M.; Guler, N.; Guo, L.; Gyurjyan, V.; Hakobyan, R. S.; Hardie, J.; Heddle, D.; Hersman, F. W.; Holtrop, M.; Hyde-Wright, C. E.; Ilieva, Y.; Ireland, D. G.; Ishkhanov, B. S.; Ito, M. M.; Jenkins, D.; Jo, H. S.; Joo, K.; Juengst, H. G.; Kalantarians, N.; Kellie, J. D.; Khandaker, M.; Kim, K.; Kim, W.; Klein, A.; Klein, F. J.; Klimenko, A. V.; Kossov, M.; Krahn, Z.; Kramer, L. H.; Kubarovsky, V.; Kuhn, J.; Kuhn, S. E.; Kuleshov, S. V.; Lachniet, J.; Laget, J. M.; Langheinrich, J.; Lawrence, D.; Li, J.; Livingston, K.; Lu, H. Y.; Lukashin, K.; MacCormick, M.; McAleer, S.; McKinnon, B.; McNabb, J.; Mecking, B. A.; Mestayer, M. D.; Meyer, C. A.; Mikhailov, K.; Minehart, R.; Mirazita, M.; Miskimen, R.; Mokeev, V.; Moriya, K.; Morrow, S. A.; Moteabbed, M.; Mutchler, G. S.; Munevar, E.; Nadel-Turonski, P.; Nasseripour, R.; Niccolai, S.; Niculescu, I.; Niczyporuk, B. B.; Niroula, M. R.; Niyazov, R. A.; Nozar, M.; Osipenko, M.; Ostrovidov, A. I.; Park, K.; Pasyuk, E.; Paterson, C.; Pierce, J.; Pivnyuk, N.; Pogorelko, O.; Pozdniakov, S.; Preedom, B.; Price, J. W.; Prok, Y.; Protopopescu, D.; Raue, B. A.; Riccardi, G.; Ricco, G.; Ripani, M.; Ritchie, B. G.; Ronchetti, F.; Rosner, G.; Rossi, P.; Sabatié, F.; Salgado, C.; Santoro, J. P.; Sapunenko, V.; Schumacher, R. A.; Serov, V. S.; Sharabian, Y. G.; Smith, E. S.; Smith, L. C.; Sober, D. I.; Stavinsky, A.; Stepanyan, S. S.; Stepanyan, S.; Stokes, B. E.; Stoler, P.; Strakovsky, I. I.; Strauch, S.; Taiuti, M.; Taylor, S.; Tedeschi, D. J.; Thoma, U.; Thompson, R.; Todor, L.; Tkachenko, S.; Tur, C.; Ungaro, M.; Vineyard, M. F.; Vlassov, A. V.; Wang, K.; Weinstein, L. B.; Weygand, D. P.; Whisnant, S.; Williams, M.; Wolin, E.; Wood, M. H.; Yegneswaran, A.; Zana, L.; Zhang, J.; Zhao, B.; Zhao, Z.

2007-04-01

Differential cross sections for the reaction γp→K*0Σ+ are presented in the photon energy range of 1.7 to 3.0 GeV. The K*0 was detected by its decay products, K+π-, in the Continuous Electron Beam Accelerator Facility's large acceptance spectrometer (CLAS) detector at the Thomas Jefferson National Accelerator Facility. These data are the first K*0 photoproduction cross sections ever published over a broad range of angles. Comparison with a theoretical model based on the vector and tensor K*-quark couplings shows good agreement with the data, except at forward angles, suggesting that the role of scalar κ meson exchange should be investigated.

Signatures of particle acceleration at SN1987a

NASA Technical Reports Server (NTRS)

Gaisser, T. K.; Stanev, Todor; Harding, Alice

1988-01-01

Young SNRs may be bright sources of energetic photons and neutrinos generated by the collisions of particles accelerated within the remnant. Due to the large opacity of the shell at these early times, a photon signal may be suppressed; at later times, due to adiabatic losses of the magnetically-trapped particles in the expanding envelope, both neutron and neutrino signals will begin to decrease. There is therefore a window during which the secondary photon signal will be at its maximum. It is presently noted that if the observed decline of the optical light curve of SN1987a is due to Ni-56, Co-56 decay, this may place upper limits on such other sources of light as a central pulsar.

Decays of bottom mesons emitting tensor mesons in the final state using the Isgur-Scora-Grinstein-Wise II model

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sharma, Neelesh; Verma, R. C.; Dhir, Rohit

2011-01-01

In this paper, we investigate phenomenologically two-body weak decays of the bottom mesons emitting pseudoscalar/vector meson and a tensor meson. Form factors are obtained using the improved Isgur-Scora-Grinstein-Wise II model. Consequently, branching ratios for the Cabibbo-Kobayashi-Maskawa-favored and Cabibbo-Kobayashi-Maskawa-suppressed decays are calculated.

Controlling moisture content of wood samples using a modified soil-pan decay method

Treesearch

Jerrold E. Winandy; Simon F. Curling; Patricia K. Lebow

2005-01-01

In wood, the threshold level below which decay cannot occur varies with species or type of wood product and other factors such as temperature, humidity, and propensity of exposure or service-use to allow rain-induced wetting and subsequent drying. The ability to control wood moisture content (MC) during laboratory decay testing could allow research on the moisture...

Transport, biodegradation and isotopic fractionation of chlorinated ethenes: modeling and parameter estimation methods

NASA Astrophysics Data System (ADS)

Béranger, Sandra C.; Sleep, Brent E.; Lollar, Barbara Sherwood; Monteagudo, Fernando Perez

2005-01-01

An analytical, one-dimensional, multi-species, reactive transport model for simulating the concentrations and isotopic signatures of tetrachloroethylene (PCE) and its daughter products was developed. The simulation model was coupled to a genetic algorithm (GA) combined with a gradient-based (GB) method to estimate the first order decay coefficients and enrichment factors. In testing with synthetic data, the hybrid GA-GB method reduced the computational requirements for parameter estimation by a factor as great as 300. The isotopic signature profiles were observed to be more sensitive than the concentration profiles to estimates of both the first order decay constants and enrichment factors. Including isotopic data for parameter estimation significantly increased the GA convergence rate and slightly improved the accuracy of estimation of first order decay constants.

Decay constants and radiative decays of heavy mesons in light-front quark model

DOE Office of Scientific and Technical Information (OSTI.GOV)

Choi, Ho-Meoyng

2007-04-01

We investigate the magnetic dipole decays V{yields}P{gamma} of various heavy-flavored mesons such as (D,D*,D{sub s},D{sub s}*,{eta}{sub c},J/{psi}) and (B,B*,B{sub s},B{sub s}*,{eta}{sub b},{upsilon}) using the light-front quark model constrained by the variational principle for the QCD-motivated effective Hamiltonian. The momentum dependent form factors F{sub VP}(q{sup 2}) for V{yields}P{gamma}* decays are obtained in the q{sup +}=0 frame and then analytically continued to the timelike region by changing q{sub perpendicular} to iq{sub perpendicular} in the form factors. The coupling constant g{sub VP{gamma}} for real photon case is then obtained in the limit as q{sup 2}{yields}0, i.e. g{sub VP{gamma}}=F{sub VP}(q{sup 2}=0). The weak decaymore » constants of heavy pseudoscalar and vector mesons are also calculated. Our numerical results for the decay constants and radiative decay widths for the heavy-flavored mesons are overall in good agreement with the available experimental data as well as other theoretical model calculations.« less

Human Sex Determination at the Edge of Ambiguity: INHERITED XY SEX REVERSAL DUE TO ENHANCED UBIQUITINATION AND PROTEASOMAL DEGRADATION OF A MASTER TRANSCRIPTION FACTOR.

PubMed

Racca, Joseph D; Chen, Yen-Shan; Yang, Yanwu; Phillips, Nelson B; Weiss, Michael A

2016-10-14

A general problem is posed by analysis of transcriptional thresholds governing cell fate decisions in metazoan development. A model is provided by testis determination in therian mammals. Its key step, Sertoli cell differentiation in the embryonic gonadal ridge, is initiated by SRY, a Y-encoded architectural transcription factor. Mutations in human SRY cause gonadal dysgenesis leading to XY female development (Swyer syndrome). Here, we have characterized an inherited mutation compatible with either male or female somatic phenotypes as observed in an XY father and XY daughter, respectively. The mutation (a crevice-forming substitution at a conserved back surface of the SRY high mobility group box) markedly destabilizes the domain but preserves specific DNA affinity and induced DNA bend angle. On transient transfection of diverse human and rodent cell lines, the variant SRY exhibited accelerated proteasomal degradation (relative to wild type) associated with increased ubiquitination; in vitro susceptibility to ubiquitin-independent ("default") cleavage by the 20S core proteasome was unchanged. The variant's gene regulatory activity (as assessed in a cellular model of the rat embryonic XY gonadal ridge) was reduced by 2-fold relative to wild-type SRY at similar levels of mRNA expression. Chemical proteasome inhibition restored native-like SRY expression and transcriptional activity in association with restored occupancy of a sex-specific enhancer element in principal downstream gene Sox9, demonstrating that the variant SRY exhibits essentially native activity on a per molecule basis. Our findings define a novel mechanism of impaired organogenesis, accelerated ubiquitin-directed proteasomal degradation of a master transcription factor leading to a developmental decision poised at the edge of ambiguity. © 2016 by The American Society for Biochemistry and Molecular Biology, Inc.

Hypoxia-inducible factor-1 (HIF-1) promotes its degradation by induction of HIF-α-prolyl-4-hydroxylases

PubMed Central

2004-01-01

An important regulator involved in oxygen-dependent gene expression is the transcription factor HIF (hypoxia-inducible factor), which is composed of an oxygen-sensitive α-subunit (HIF-1α or HIF-2α) and a constitutively expressed β-subunit. In normoxia, HIF-1α is destabilized by post-translational hydroxylation of Pro-564 and Pro-402 by a family of oxygen-sensitive dioxygenases. The three HIF-modifying human enzymes have been termed prolyl hydroxylase domain containing proteins (PHD1, PHD2 and PHD3). Prolyl hydroxylation leads to pVHL (von-Hippel-Lindau protein)-dependent ubiquitination and rapid proteasomal degradation of HIF-1α. In the present study, we report that human PHD2 and PHD3 are induced by hypoxia in primary and transformed cell lines. In the human osteosarcoma cell line, U2OS, selective suppression of HIF-1α expression by RNA interference resulted in a complete loss of hypoxic induction of PHD2 and PHD3. Induction of PHD2 by hypoxia was lost in pVHL-deficient RCC4 cells. These results suggest that hypoxic induction of PHD2 and PHD3 is critically dependent on HIF-α. Using a VHL capture assay, we demonstrate that HIF-α prolyl-4-hydroxylase capacity of cytoplasmic and nuclear protein extracts was enhanced by prolonged exposure to hypoxia. Degradation of HIF-1α after reoxygenation was accelerated, which demonstrates functional relevance of the present results. We propose a direct, negative regulatory mechanism, which limits accumulation of HIF-1α in hypoxia and leads to accelerated degradation on reoxygenation after long-term hypoxia. PMID:15104534

Early Induction of NRF2 Antioxidant Pathway by RHBDF2 Mediates Rapid Cutaneous Wound Healing

PubMed Central

Hosur, Vishnu; Burzenski, Lisa M.; Stearns, Timothy M.; Farley, Michelle L.; Sundberg, John P.; Wiles, Michael V.; Shultz, Leonard D.

2017-01-01

Rhomboid family protein RHBDF2, an upstream regulator of the epidermal growth factor (EGF) receptor signaling, has been implicated in cutaneous wound healing. However, the underlying molecular mechanisms are still emerging. In humans, a gain-of-function mutation in the RHBDF2 gene accelerates cutaneous wound healing in an EGFR-dependent manner. Likewise, a gain-of-function mutation in the mouse Rhbdf2 gene (Rhbdf2cub/cub) shows a regenerative phenotype (rapid ear-hole closure) resulting from constitutive activation of the EGFR pathway. Because the RHBDF2-regulated EGFR pathway is relevant to cutaneous wound healing in humans, we used Rhbdf2cub/cub mice to investigate the biological networks and pathways leading to accelerated ear-hole closure, with the goal of identifying therapeutic targets potentially effective in promoting wound healing in humans. Comparative transcriptome analysis of ear pinna tissue from Rhbdf2cub/cub and Rhbdf2+/+ mice at 0h, 15 min, 2h, and 24h post-wounding revealed an early induction of the nuclear factor E2-related factor 2 (NRF2)-mediated anti-oxidative pathway (0h and 15 min), followed by the integrin-receptor aggregation pathway (2h) as early-stage events immediately and shortly after wounding in Rhbdf2cub/cub mice. Additionally, we observed genes enriched for the Fc fragment of the IgG receptor IIIa (FCGR3A)-mediated phagocytosis pathway 24h post-wounding. Although cutaneous wound repair in healthy individuals is generally non-problematic, it can be severely impaired due to aging, diabetes, and chronic inflammation. This study suggests that activation of the NRF2-antioxidant pathway by rhomboid protein RHBDF2 might be beneficial in treating chronic non-healing wounds. PMID:28268192

Early induction of NRF2 antioxidant pathway by RHBDF2 mediates rapid cutaneous wound healing.

PubMed

Hosur, Vishnu; Burzenski, Lisa M; Stearns, Timothy M; Farley, Michelle L; Sundberg, John P; Wiles, Michael V; Shultz, Leonard D

2017-04-01

Rhomboid family protein RHBDF2, an upstream regulator of the epidermal growth factor (EGF) receptor signaling, has been implicated in cutaneous wound healing. However, the underlying molecular mechanisms are still emerging. In humans, a gain-of-function mutation in the RHBDF2 gene accelerates cutaneous wound healing in an EGFR-dependent manner. Likewise, a gain-of-function mutation in the mouse Rhbdf2 gene (Rhbdf2 cub/cub ) shows a regenerative phenotype (rapid ear-hole closure) resulting from constitutive activation of the EGFR pathway. Because the RHBDF2-regulated EGFR pathway is relevant to cutaneous wound healing in humans, we used Rhbdf2 cub/cub mice to investigate the biological networks and pathways leading to accelerated ear-hole closure, with the goal of identifying therapeutic targets potentially effective in promoting wound healing in humans. Comparative transcriptome analysis of ear pinna tissue from Rhbdf2 cub/cub and Rhbdf2 +/+ mice at 0h, 15min, 2h, and 24h post-wounding revealed an early induction of the nuclear factor E2-related factor 2 (NRF2)-mediated anti-oxidative pathway (0h and 15min), followed by the integrin-receptor aggregation pathway (2h) as early-stage events immediately and shortly after wounding in Rhbdf2 cub/cub mice. Additionally, we observed genes enriched for the Fc fragment of the IgG receptor IIIa (FCGR3A)-mediated phagocytosis pathway 24h post-wounding. Although cutaneous wound repair in healthy individuals is generally non-problematic, it can be severely impaired due to aging, diabetes, and chronic inflammation. This study suggests that activation of the NRF2-antioxidant pathway by rhomboid protein RHBDF2 might be beneficial in treating chronic non-healing wounds. Copyright © 2017 Elsevier Inc. All rights reserved.

A precision measurement of the W boson decaying to muon-neutrino charge asymmetry at a center of mass energy of 1.96 TeV using the D0 detector

NASA Astrophysics Data System (ADS)

Sengupta, Sinjini

This dissertation describes a measurement of the muon charge asymmetry from W boson decays. The charge asymmetry provides useful information about the momentum distribution of u and d quarks inside the proton. The charge asymmetry was measured using ≈ 230 pb-1 of data collected between 2002 and 2004 using the DO detector at the Tevatron collider at Fermi National Accelerator Laboratory. In the Tevatron, protons and antiprotons collide with a center of mass energy of 1.96 TeV. The signal consists of one high transverse momentum muon and missing transverse energy while the background which comes from other events also producing a high transverse momentum muon. As the charge asymmetry depends on the number of positive and negative muons from the W boson decay in each bin of pseudorapidity, the background are removed. The resultant distribution is compared with predictions from NLO calculations using the CTEQ6.1M and the MRST02 PDFs. This is the first approved result for the W charge asymmetry from DO.

Long-lived neutral-kaon flux measurement for the KOTO experiment

DOE PAGES

Masuda, T.; Ahn, J. K.; Banno, S.; ...

2016-01-24

The KOTO(K 0 at Tokai) experiment aims to observe the CP-violating rare decay K L → π 0νν¯ over bar by using a long-lived neutral-kaon beam produced by the 30 GeV proton beam at the Japan Proton Accelerator Research Complex. The K L flux is an essential parameter for the measurement of the branching fraction. Three K L neutral decay modes, K L → 3 π 0, K L → 2 π 0, and K L → 2γ, were used to measure the K L flux in the beam line in the 2013 KOTO engineering run. A Monte Carlo simulationmore » was used to estimate the detector acceptance for these decays. Agreement was found between the simulation model and the experimental data, and the remaining systematic uncertainty was estimated at the 1.4% level. Here, the K L flux was measured as (4.183 ± 0.017 stat. ± 0.059 sys.) x 10 7 K L per 2 x 10 14 protons on a 66-mm-long Au target.« less

DOE-high energy physics contract with the University of Hawaii. Final report, December 1, 1980-June 30, 1984

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

1986-06-02

Experimental research covered includes involvement in SLAC and Fermilab accelerator experiments and construction of the ''Muon String'' of the DUMAND project. Activities also included planning of future experiments at the SLC and Tevatron. Experiments addressed the search for the free quark, gluon radiation, reduced upper limits for the mass of neutrinos. The theoretical program includes exact calculation of flavor changing processes within the standard model, constraints on the weak coupling of heavy quarks, neutrino oscillation, the role of DEMONS in superconductivity, extended electroweak models, gauge models, the origin of electron/muon asymmetry in the beam dump, SU(5) and departures in unification.more » QCD and vector dominance predictions were reconciled in the electromagnetic decays of neutral pions and eta mesons, and it was proposed that the electron plus jet events seen by UAl along with their W events are to interpreted as the production and decay of top. The possibility of observable particle-antiparticle rate differences in hyperon decays as a test of CP-invariance was proposed. (LEW)« less

Direct Evidence of Exciton-Exciton Annihilation in Single-Crystalline Organic Metal Halide Nanotube Assemblies.

PubMed

Ma, Ying-Zhong; Lin, Haoran; Du, Mao-Hua; Doughty, Benjamin; Ma, Biwu

2018-05-03

Excitons in low-dimensional organic-inorganic metal halide hybrid structures are commonly thought to undergo rapid self-trapping following creation due to strong quantum confinement and exciton-phonon interaction. Here we report an experimental study probing the dynamics of these self-trapped excitons in the single-crystalline bulk assemblies of 1D organic metal halide nanotubes, (C 6 H 13 N 4 ) 3 Pb 2 Br 7 . Through time-resolved photoluminescence (PL) measurements at different excitation intensities, we observed a marked variation in the PL decay behavior that is manifested by an accelerated decay rate with increasing excitation fluence. Our results offer direct evidence of the occurrence of an exciton-exciton annihilation process, a nonlinear relaxation phenomenon that takes place only when some of the self-trapped excitons become mobile and can approach either each other or those trapped excitons. We further identify a fast and dominant PL decay component with a lifetime of ∼2 ns with a nearly invariant relative area for all acquired PL kinetics, suggesting that this rapid relaxation process is intrinsic.

Direct Evidence of Exciton–Exciton Annihilation in Single-Crystalline Organic Metal Halide Nanotube Assemblies

DOE PAGES

Ma, Ying -Zhong; Lin, Haoran; Du, Mao -Hua; ...

2018-04-11

Excitons in low-dimensional organic–inorganic metal halide hybrid structures are commonly thought to undergo rapid self-trapping following creation due to strong quantum confinement and exciton–phonon interaction. Here we report an experimental study probing the dynamics of these self-trapped excitons in the single-crystalline bulk assemblies of 1D organic metal halide nanotubes, (C 6H 13N 4) 3Pb 2Br 7. Through time-resolved photoluminescence (PL) measurements at different excitation intensities, we observed a marked variation in the PL decay behavior that is manifested by an accelerated decay rate with increasing excitation fluence. Our results offer direct evidence of the occurrence of an exciton–exciton annihilation process,more » a nonlinear relaxation phenomenon that takes place only when some of the self-trapped excitons become mobile and can approach either each other or those trapped excitons. As a result, we further identify a fast and dominant PL decay component with a lifetime of ~2 ns with a nearly invariant relative area for all acquired PL kinetics, suggesting that this rapid relaxation process is intrinsic.« less

Measurement of Branching Fractions for Two-Body Charmless B Decays to Charged Pions and Kaons at BaBar

DOE Office of Scientific and Technical Information (OSTI.GOV)

Barrera, Barbara

The authors present preliminary results of a search for charmless two-body B decays to charged pions and kaons using data collected by the BaBar detector at the Stanford Linear Accelerator Center's PEP-II Storage ring. In a sample of 8.8 million produced B anti-B pairs the authors measure the branching fractions beta(B{sup 0} --> pi{sup +}pi{sup {minus}}) = (9.3{sub {minus}2.3{minus}1.4}{sup +2.6+1.2}) x 10{sup {minus}6} and beta(B{sup 0} --> K{sup +}pi{sup {minus}}) = (12.5{sub {minus}2.6{minus}1.7}{sup +3.0+1.3}) x 10{sup {minus}6}, where the first uncertainty is statistical and the second is systematic. For the decay B{sup 0} --> K{sup +}K{sup {minus}} they find nomore » significant signal and set an upper limit of beta(B{sup 0} --> K{sup +}K{sup {minus}}) < 6.6 x 10{sup {minus}6} at the 90% confidence level.« less

Direct Evidence of Exciton–Exciton Annihilation in Single-Crystalline Organic Metal Halide Nanotube Assemblies

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ma, Ying -Zhong; Lin, Haoran; Du, Mao -Hua

Excitons in low-dimensional organic–inorganic metal halide hybrid structures are commonly thought to undergo rapid self-trapping following creation due to strong quantum confinement and exciton–phonon interaction. Here we report an experimental study probing the dynamics of these self-trapped excitons in the single-crystalline bulk assemblies of 1D organic metal halide nanotubes, (C 6H 13N 4) 3Pb 2Br 7. Through time-resolved photoluminescence (PL) measurements at different excitation intensities, we observed a marked variation in the PL decay behavior that is manifested by an accelerated decay rate with increasing excitation fluence. Our results offer direct evidence of the occurrence of an exciton–exciton annihilation process,more » a nonlinear relaxation phenomenon that takes place only when some of the self-trapped excitons become mobile and can approach either each other or those trapped excitons. As a result, we further identify a fast and dominant PL decay component with a lifetime of ~2 ns with a nearly invariant relative area for all acquired PL kinetics, suggesting that this rapid relaxation process is intrinsic.« less

Accelerators of Osteogenesis by Recombinant Human Bone Morphogenetic Protein-2

PubMed Central

Okubo, Yasunori; Kusumoto, Kenji; Bessho, Kazuhisa

2007-01-01

Bone morphogenetic protein (BMP) appears to be one of the most promising cytokine and for clinical use in reconstructive surgery for bony defects and augmentation. To evaluate the effect of basic fibroblast growth factor (bFGF), FK506, elcatonin, and hyperbaric oxygenation (HBO) on osteoinduction by recombinant human bone morphogenetic protein-2 (rhBMP-2), 2 or 5 μg of rhBMP-2 was implanted into intramuscular sites of rats. At 21 days after implantation, the osteoinductive activity in the treatment group and control group was compared radiographically, biochemically, and histologically. The amount of new bone in the treatment group was significantly greater than that in the control group. The alkaline phosphatase activity and calcium content in the treatment group were significantly higher than those in the control group. These results suggest that bFGF, FK506, elcatonin, and HBO accelerated the activity and rate of osteoinduction by rhBMP2. These results may be useful when BMP is applied clinically in near future. PMID:21901062

Nonleptonic decays of B →(f1(1285 ),f1(1420 ))V in the perturbative QCD approach

NASA Astrophysics Data System (ADS)

Liu, Xin; Xiao, Zhen-Jun; Zou, Zhi-Tian

2016-12-01

We investigate the branching ratios, the polarization fractions, the direct C P -violating asymmetries, and the relative phases in 20 nonleptonic decay modes of B →f1V within the framework of the perturbative QCD approach at leading order with f1 including two 3P1-axial-vector states f1(1285 ) and f1(1420 ) . Here, B denotes B+, B0, and Bs0 mesons and V stands for the lightest vector mesons ρ , K*, ω , and ϕ , respectively. The Bs0→f1V decays are studied theoretically for the first time in the literature. Together with the angle ϕf1≈(24-2.7+3.2)∘ extracted from the measurement through Bd /s→J /ψ f1(1285 ) modes for the f1(1285 )-f1(1420 ) mixing system, it is of great interest to find phenomenologically some modes such as the tree-dominated B+→f1ρ+ and the penguin-dominated B+,0→f1K*+,0 , Bs0→f1ϕ with large branching ratios around O (10-6) or even O (10-5), which are expected to be measurable at the LHCb and/or the Belle-II experiments in the near future. The good agreement (sharp contrast) of branching ratios and decay pattern for B+→f1ρ+ , B+,0→f1(1285 )K*+,0[B+,0→f1(1420 )K*+,0] decays between QCD factorization and perturbative QCD factorization predictions can help us to distinguish these two rather different factorization approaches via precision measurements, which would also be helpful for us in exploring the annihilation decay mechanism through its important roles for the considered B →f1V decays.

Transforming Growth Factor-β1 Accelerates Resorption of a Calcium Carbonate Biomaterial in Periodontal Defects.

PubMed

Koo, Ki-Tae; Susin, Cristiano; Wikesjö, Ulf M E; Choi, Seong-Ho; Kim, Chong-Kwan

2007-04-01

In a previous study, recombinant human transforming growth factor-beta1 (rhTGF-β 1 ) in a calcium carbonate carrier was implanted into critical-size, supraalveolar periodontal defects under conditions for guided tissue regeneration (GTR) to study whether rhTGF-β 1 would enhance or accelerate periodontal regeneration. The results showed minimal benefits of rhTGF-β 1 , and a clear account for this could not be offered. One potential cause may be that the rhTGF-β 1 formulation was biologically inactive. Several growth or differentiation factors have been suggested to accelerate degradation of biomaterials used as carriers. The objective of this study was to evaluate possible activity of rhTGF-β 1 on biodegradation of the calcium carbonate carrier. rhTGF-β 1 in a putty-formulated particulate calcium carbonate carrier was implanted into critical-size, supraalveolar periodontal defects under conditions for GTR in five beagle dogs. Contralateral defects received the calcium carbonate carrier combined with GTR without rhTGF-β 1 (control). The animals were euthanized at week 4 post-surgery and block biopsies of the defect sites were collected for histologic and histometric analysis. Radiographs were obtained at defect creation and weeks 2 and 4 after defect creation. No statistically significant differences were observed in new bone formation (bone height and area) among the treatments. However, total residual carrier was significantly reduced in sites receiving rhTGF-β 1 compared to control (P = 0.04). Similarly, carrier density was considerably reduced in sites receiving rhTGF-β 1 compared to control; the difference was borderline statistically significant (P = 0.06). Within the limitations of the study, it may be concluded that rhTGF-β 1 accelerates biodegradation of a particulate calcium carbonate biomaterial, indicating a biologic activity of the rhTGF-β 1 formulation apparently not encompassing enhanced or accelerated periodontal regeneration. © 2007 American Academy of Periodontology.

Transforming growth factor-beta1 accelerates resorption of a calcium carbonate biomaterial in periodontal defects.

PubMed

Koo, Ki-Tae; Susin, Cristiano; Wikesjö, Ulf M E; Choi, Seong-Ho; Kim, Chong-Kwan

2007-04-01

In a previous study, recombinant human transforming growth factor-beta1 (rhTGF-beta(1)) in a calcium carbonate carrier was implanted into critical-size, supraalveolar periodontal defects under conditions for guided tissue regeneration (GTR) to study whether rhTGF-beta(1) would enhance or accelerate periodontal regeneration. The results showed minimal benefits of rhTGF-beta(1), and a clear account for this could not be offered. One potential cause may be that the rhTGF-beta(1) formulation was biologically inactive. Several growth or differentiation factors have been suggested to accelerate degradation of biomaterials used as carriers. The objective of this study was to evaluate possible activity of rhTGF-beta(1) on biodegradation of the calcium carbonate carrier. rhTGF-beta(1) in a putty-formulated particulate calcium carbonate carrier was implanted into critical-size, supraalveolar periodontal defects under conditions for GTR in five beagle dogs. Contralateral defects received the calcium carbonate carrier combined with GTR without rhTGF-beta(1) (control). The animals were euthanized at week 4 post-surgery and block biopsies of the defect sites were collected for histologic and histometric analysis. Radiographs were obtained at defect creation and weeks 2 and 4 after defect creation. No statistically significant differences were observed in new bone formation (bone height and area) among the treatments. However, total residual carrier was significantly reduced in sites receiving rhTGF-beta(1) compared to control (P = 0.04). Similarly, carrier density was considerably reduced in sites receiving rhTGF-beta(1) compared to control; the difference was borderline statistically significant (P = 0.06). Within the limitations of the study, it may be concluded that rhTGF-beta(1) accelerates biodegradation of a particulate calcium carbonate biomaterial, indicating a biologic activity of the rhTGF-beta(1) formulation apparently not encompassing enhanced or accelerated periodontal regeneration.

Estimation of decay rates for fecal indicator bacteria and bacterial pathogens in agricultural field-applied manure

EPA Science Inventory

Field-applied manure is an important source of pathogenic exposure in surface water bodies for humans and ecological receptors. We analyzed the persistence and decay of fecal indicator bacteria and bacterial pathogens from three sources (cattle, poultry, swine) for agricultural f...

A Specialized Multi-Transmit Head Coil for High Resolution fMRI of the Human Visual Cortex at 7T.

PubMed

Sengupta, Shubharthi; Roebroeck, Alard; Kemper, Valentin G; Poser, Benedikt A; Zimmermann, Jan; Goebel, Rainer; Adriany, Gregor

2016-01-01

To design, construct and validate radiofrequency (RF) transmit and receive phased array coils for high-resolution visual cortex imaging at 7 Tesla. A 4 channel transmit and 16 channel receive array was constructed on a conformal polycarbonate former. Transmit field efficiency and homogeneity were simulated and validated, along with the Specific Absorption Rate, using [Formula: see text] mapping techniques and electromagnetic simulations. Receiver signal-to-noise ratio (SNR), temporal SNR (tSNR) across EPI time series, g-factors for accelerated imaging and noise correlations were evaluated and compared with a commercial 32 channel whole head coil. The performance of the coil was further evaluated with human subjects through functional MRI (fMRI) studies at standard and submillimeter resolutions of upto 0.8mm isotropic. The transmit and receive sections were characterized using bench tests and showed good interelement decoupling, preamplifier decoupling and sample loading. SNR for the 16 channel coil was ∼ 1.5 times that of the commercial coil in the human occipital lobe, and showed better g-factor values for accelerated imaging. fMRI tests conducted showed better response to Blood Oxygen Level Dependent (BOLD) activation, at resolutions of 1.2mm and 0.8mm isotropic. The 4 channel phased array transmit coil provides homogeneous excitation across the visual cortex, which, in combination with the dual row 16 channel receive array, makes for a valuable research tool for high resolution anatomical and functional imaging of the visual cortex at 7T.

A drug-induced accelerated senescence (DIAS) is a possibility to study aging in time lapse.

PubMed

Alili, Lirija; Diekmann, Johanna; Giesen, Melanie; Holtkötter, Olaf; Brenneisen, Peter

2014-06-01

Currently, the oxidative stress (or free radical) theory of aging is the most popular explanation of how aging occurs at the molecular level. Accordingly, a stress-induced senescence-like phenotype of human dermal fibroblasts can be induced in vitro by the exposure of human diploid fibroblasts to subcytotoxic concentrations of hydrogen peroxide. However, several biomarkers of replicative senescence e.g. cell cycle arrest and enlarged morphology are abrogated 14 days after treatment, indicating that reactive oxygen species (ROS) rather acts as a trigger for short-term senescence (1-3 days) than being responsible for the maintenance of the senescence-like phenotype. Further, DNA-damaging factors are discussed resulting in a permanent senescent cell type. To induce long-term premature senescence and to understand the molecular alterations occurring during the aging process, we analyzed mitomycin C (MMC) as an alkylating DNA-damaging agent and ROS producer. Human dermal fibroblasts (HDF), used as model for skin aging, were exposed to non-cytotoxic concentrations of MMC and analyzed for potential markers of cellular aging, for example enlarged morphology, activity of senescence-associated-ß-galactosidase, cell cycle arrest, increased ROS production and MMP1-activity, which are well-documented for HDF in replicative senescence. Our data show that mitomycin C treatment results in a drug-induced accelerated senescence (DIAS) with long-term expression of senescence markers, demonstrating that a combination of different susceptibility factors, here ROS and DNA alkylation, are necessary to induce a permanent senescent cell type.

Mouse ENU Mutagenesis to Understand Immunity to Infection: Methods, Selected Examples, and Perspectives

PubMed Central

Caignard, Grégory; Eva, Megan M.; van Bruggen, Rebekah; Eveleigh, Robert; Bourque, Guillaume; Malo, Danielle; Gros, Philippe; Vidal, Silvia M.

2014-01-01

Infectious diseases are responsible for over 25% of deaths globally, but many more individuals are exposed to deadly pathogens. The outcome of infection results from a set of diverse factors including pathogen virulence factors, the environment, and the genetic make-up of the host. The completion of the human reference genome sequence in 2004 along with technological advances have tremendously accelerated and renovated the tools to study the genetic etiology of infectious diseases in humans and its best characterized mammalian model, the mouse. Advancements in mouse genomic resources have accelerated genome-wide functional approaches, such as gene-driven and phenotype-driven mutagenesis, bringing to the fore the use of mouse models that reproduce accurately many aspects of the pathogenesis of human infectious diseases. Treatment with the mutagen N-ethyl-N-nitrosourea (ENU) has become the most popular phenotype-driven approach. Our team and others have employed mouse ENU mutagenesis to identify host genes that directly impact susceptibility to pathogens of global significance. In this review, we first describe the strategies and tools used in mouse genetics to understand immunity to infection with special emphasis on chemical mutagenesis of the mouse germ-line together with current strategies to efficiently identify functional mutations using next generation sequencing. Then, we highlight illustrative examples of genes, proteins, and cellular signatures that have been revealed by ENU screens and have been shown to be involved in susceptibility or resistance to infectious diseases caused by parasites, bacteria, and viruses. PMID:25268389

Fluid Physics in a Fluctuating Acceleration Environment

NASA Technical Reports Server (NTRS)

Drolet, Francois; Vinals, Jorge

1999-01-01

Our program of research aims at developing a stochastic description of the residual acceleration field onboard spacecraft (g-jitter) to describe in quantitative detail its effect on fluid motion. Our main premise is that such a statistical description is necessary in those cases in which the characteristic time scales of the process under investigation are long compared with the correlation time of g-jitter. Although a clear separation between time scales makes this approach feasible, there remain several difficulties of practical nature: (i), g-jitter time series are not statistically stationary but rather show definite dependences on factors such as active or rest crew periods; (ii), it is very difficult to extract reliably the low frequency range of the power spectrum of the acceleration field. This range controls the magnitude of diffusive processes; and (iii), models used to date are Gaussian, but there is evidence that large amplitude disturbances occur much more frequently than a Gaussian distribution would predict. The lack of stationarity does not constitute a severe limitation in practice, since the intensity of the stochastic components changes very slowly during space missions (perhaps over times of the order of hours). A separate analysis of large amplitude disturbances has not been undertaken yet, but it does not seem difficult a priori to devise models that may describe this range better than a Gaussian distribution. The effect of low frequency components, on the other hand, is more difficult to ascertain, partly due to the difficulty associated with measuring them, and partly because they may be indistinguishable from slowly changing averages. This latter effect is further complicated by the lack of statistical stationarity of the time series. Recent work has focused on the effect of stochastic modulation on the onset of oscillatory instabilities as an example of resonant interaction between the driving acceleration and normal modes of the system, and on cavity flow as an example of how an oscillatory response under periodic driving becomes diffusive if the forcing is random instead. This paper describes three different topics that illustrate behavior that is peculiar to a stochastic acceleration field. In the first case, we show that g-jitter can induce effective attractive or repulsive forces between a pair of spherical particles that are suspended in an incompressible fluid of different density provided that the momentum diffusion length is larger than the interparticle separation (as in the case in most colloidal suspensions). Second, a stochastic modulation of the control parameter in the vicinity of a pitchfork or supercritical bifurcation is known not to affect the location of the threshold. We show, however, that resonance between the modulation and linearly stable modes close to onset can lead to a shift in threshold. Finally, we discuss the classical problem of vorticity diffusion away from a plane boundary that is being vibrated along its own plane. Periodic motion with zero average vorticity production results in an exponential decay of the vorticity away from the boundary. Random vibration, on the other hand, results in power law decay away from the boundary even if vorticity production averages to zero.

Scaling effects in a non-linear electromagnetic energy harvester for wearable sensors

NASA Astrophysics Data System (ADS)

Geisler, M.; Boisseau, S.; Perez, M.; Ait-Ali, I.; Perraud, S.

2016-11-01

In the field of inertial energy harvesters targeting human mechanical energy, the ergonomics of the solutions impose to find the best compromise between dimensions reduction and electrical performance. In this paper, we study the properties of a non-linear electromagnetic generator at different scales, by performing simulations based on an experimentally validated model and real human acceleration recordings. The results display that the output power of the structure is roughly proportional to its scaling factor raised to the power of five, which indicates that this system is more relevant at lengths over a few centimetres.

Genome-Wide Identification of Regulatory Sequences Undergoing Accelerated Evolution in the Human Genome.

PubMed

Dong, Xinran; Wang, Xiao; Zhang, Feng; Tian, Weidong

2016-10-01

Accelerated evolution of regulatory sequence can alter the expression pattern of target genes, and cause phenotypic changes. In this study, we used DNase I hypersensitive sites (DHSs) to annotate putative regulatory sequences in the human genome, and conducted a genome-wide analysis of the effects of accelerated evolution on regulatory sequences. Working under the assumption that local ancient repeat elements of DHSs are under neutral evolution, we discovered that ∼0.44% of DHSs are under accelerated evolution (ace-DHSs). We found that ace-DHSs tend to be more active than background DHSs, and are strongly associated with epigenetic marks of active transcription. The target genes of ace-DHSs are significantly enriched in neuron-related functions, and their expression levels are positively selected in the human brain. Thus, these lines of evidences strongly suggest that accelerated evolution on regulatory sequences plays important role in the evolution of human-specific phenotypes. © The Author 2016. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution.

Measurement of the top quark pair production cross-section in dimuon final states in proton-antiproton collisions at 1.96 TeV

DOE Office of Scientific and Technical Information (OSTI.GOV)

Konrath, Jens Peter

2008-10-24

Particle physics deals with the fundamental building blocks of matter and their interactions. The vast number of subatomic particles can be reduced to twelve fundamental fermions, which interact by the exchange of spin-1 particles as described in the Standard Model (SM) of particle physics. The SM provides the best description of the subatomic world to date, despite the fact it does not include gravitation. Following the relation Λ = h/p, where h is Planck's constant, for the examination of physics at subatomic scales with size Λ probes with high momenta p are necessary. These high energies are accessible through particlemore » colliders. Here, particles are accelerated and brought to collision at interaction points at which detectors are installed to record these particle collisions. Until the anticipated start-up of the Large Hadron Collider at CERN, the Tevatron collider at Fermilab near Chicago is the highest energy collider operating in the world, colliding protons and anti-protons at a center-of-mass energy of √s = 1.96 TeV. Its two interaction points are covered by the multi purpose particle detectors D0 and CDF. During the first data-taking period, known as Run I, the Tevatron operated at a center-of-mass energy of 1.8 TeV. This run period lasted from 1992 to 1996. During this period, the long-predicted top quark was discovered. From 1996 and 2001, the accelerator was upgraded to deliver higher instantaneous luminosities at its current center-of-mass energy. At the same time, the experiments were upgraded to take full advantage of the upgraded accelerator complex. The Tevatron is currently the only accelerator in the world with a sufficient energy to produce top quarks. Studying top quark production, decay and properties is an important part of the D0 and CDF physics programs. Because of its large mass, the top quark is a unique probe of the Standard Model, and an interesting environment to search for new physics. In this thesis, a measurement of the production cross-section of top quark pairs decaying to two muons is presented. In addition, a Monte Carlo study of the top quark spin correlation measurement was carried out. This thesis is laid out as follows: chapter two gives a short overview over the Standard Model of particle physics and the theoretical aspects of unpolarized and polarized top quark production and decay, chapter three describes the accelerator complex and the D0 experiment whose data is used in this analysis. The Reconstruction of events recorded with the D0 detector is explained in chapter four and the data and Monte Carlo samples used are presented in chapter five. Finally, the cross-section measurement is described in chapter six and the Monte Carlo study of top quark spin correlations in chapter seven.« less

Reactivity of organism in prolonged space flights

NASA Technical Reports Server (NTRS)

Vasilyev, P. V.

1980-01-01

An analysis of published data are presented as well as the results of experiments which show that the state of weightlessness and hypodynamia result in a reduced orthostatic and vestibular resistance, increased sensitivity to infections, decreased endurance of accelerations and physical exercises, and altered reactivity of the organism to drugs. Various consequences of weightlessness on the human body, especially weightlessness combined with other factors linked to long space flights are also considered.

Inhibition of the proliferation and acceleration of migration of vascular endothelial cells by increased cysteine-rich motor neuron 1

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nakashima, Yukiko; Morimoto, Mayuka; Toda, Ken-ichi

2015-07-03

Cysteine-rich motor neuron 1 (CRIM1) is upregulated only in extracellular matrix gels by angiogenic factors such as vascular endothelial growth factor (VEGF). It then plays a critical role in the tube formation of endothelial cells. In the present study, we investigated the effects of increased CRIM1 on other endothelial functions such as proliferation and migration. Knock down of CRIM1 had no effect on VEGF-induced proliferation or migration of human umbilical vein endothelial cells (HUVECs), indicating that basal CRIM1 is not involved in the proliferation or migration of endothelial cells. Stable CRIM1-overexpressing endothelial F-2 cells, termed CR1 and CR2, were constructed,more » because it was difficult to prepare monolayer HUVECs that expressed high levels of CRIM1. Proliferation was reduced and migration was accelerated in both CR1 and CR2 cells, compared with normal F-2 cells. Furthermore, the transient overexpression of CRIM1 resulted in decreased proliferation and increased migration of bovine aortic endothelial cells. In contrast, neither proliferation nor migration of COS-7 cells were changed by the overexpression of CRIM1. These results demonstrate that increased CRIM1 reduces the proliferation and accelerates the migration of endothelial cells. These CRIM1 effects might contribute to tube formation of endothelial cells. CRIM1 induced by angiogenic factors may serve as a regulator in endothelial cells to switch from proliferating cells to morphological differentiation. - Highlights: • CRIM1 was upregulated only in tubular endothelial cells, but not in monolayers. • Increased CRIM1 reduced the proliferation of endothelial cells. • Increased CRIM1 accelerated the migration of endothelial cells. • Increased CRIM1 had no effect on the proliferation or migration of COS-7 cells.« less

Vibrotactile masking experiments reveal accelerated somatosensory processing in congenitally blind braille readers.

PubMed

Bhattacharjee, Arindam; Ye, Amanda J; Lisak, Joy A; Vargas, Maria G; Goldreich, Daniel

2010-10-27

Braille reading is a demanding task that requires the identification of rapidly varying tactile patterns. During proficient reading, neighboring characters impact the fingertip at ∼100 ms intervals, and adjacent raised dots within a character at 50 ms intervals. Because the brain requires time to interpret afferent sensorineural activity, among other reasons, tactile stimuli separated by such short temporal intervals pose a challenge to perception. How, then, do proficient Braille readers successfully interpret inputs arising from their fingertips at such rapid rates? We hypothesized that somatosensory perceptual consolidation occurs more rapidly in proficient Braille readers. If so, Braille readers should outperform sighted participants on masking tasks, which demand rapid perceptual processing, but would not necessarily outperform the sighted on tests of simple vibrotactile sensitivity. To investigate, we conducted two-interval forced-choice vibrotactile detection, amplitude discrimination, and masking tasks on the index fingertips of 89 sighted and 57 profoundly blind humans. Sighted and blind participants had similar unmasked detection (25 ms target tap) and amplitude discrimination (compared with 100 μm reference tap) thresholds, but congenitally blind Braille readers, the fastest readers among the blind participants, exhibited significantly less masking than the sighted (masker, 50 Hz, 50 μm; target-masker delays, ±50 and ±100 ms). Indeed, Braille reading speed correlated significantly and specifically with masking task performance, and in particular with the backward masking decay time constant. We conclude that vibrotactile sensitivity is unchanged but that perceptual processing is accelerated in congenitally blind Braille readers.

Vibrotactile masking experiments reveal accelerated somatosensory processing in congenitally blind Braille readers

PubMed Central

Bhattacharjee, Arindam; Ye, Amanda J.; Lisak, Joy A.; Vargas, Maria G.; Goldreich, Daniel

2010-01-01

Braille reading is a demanding task that requires the identification of rapidly varying tactile patterns. During proficient reading, neighboring characters impact the fingertip at about 100-ms intervals, and adjacent raised dots within a character at 50-ms intervals. Because the brain requires time to interpret afferent sensorineural activity, among other reasons, tactile stimuli separated by such short temporal intervals pose a challenge to perception. How, then, do proficient Braille readers successfully interpret inputs arising from their fingertips at such rapid rates? We hypothesized that somatosensory perceptual consolidation occurs more rapidly in proficient Braille readers. If so, Braille readers should outperform sighted participants on masking tasks, which demand rapid perceptual processing, but would not necessarily outperform the sighted on tests of simple vibrotactile sensitivity. To investigate, we conducted two-interval forced-choice vibrotactile detection, amplitude discrimination, and masking tasks on the index fingertips of 89 sighted and 57 profoundly blind humans. Sighted and blind participants had similar unmasked detection (25-ms target tap) and amplitude discrimination (compared to 100-micron reference tap) thresholds, but congenitally blind Braille readers, the fastest readers among the blind participants, exhibited significantly less masking than the sighted (masker: 50-Hz, 50-micron; target-masker delays ±50 and ±100 ms). Indeed, Braille reading speed correlated significantly and specifically with masking task performance, and in particular with the backward masking decay time constant. We conclude that vibrotactile sensitivity is unchanged, but that perceptual processing is accelerated in congenitally blind Braille readers. PMID:20980584

Collisionless Shocks and Particle Acceleration.

NASA Astrophysics Data System (ADS)

Malkov, M.

2016-12-01

Collisionless shocks emerged in the 50s and 60s of the last century as an important branch of plasma physics and have remained ever since. New applications pose new challenges to our understanding of collisionless shock mechanisms. Particle acceleration in astrophysical settings, primarily studied concerning the putative origin of cosmic rays (CR) in supernova remnant (SNR) shocks, stands out with the collisionless shock mechanism being the key. Among recent laboratory applications, a laser-based tabletop proton accelerator is an affordable compact alternative to big synchrotron accelerators. The much-anticipated proof of cosmic ray (CR) acceleration in supernova remnants is hindered by our limited understanding of collisionless shock mechanisms. Over the last decade, dramatically improved observations were puzzling the theorists with unexpected discoveries. The difference between the helium/carbon and proton CR rigidity (momentum to charge ratio) spectra, seemingly inconsistent with the acceleration and propagation theories, and the perplexing positron excess in the 10-300 GeV range are just two recent examples. The latter is now also actively discussed in the particle physics and CR communities as a possible signature of decay or annihilation of hypothetical dark matter particles. By considering an initial (injection) phase of a diffusive shock acceleration mechanism, including particle reflection off the shock front - where an elemental similarity of particle dynamics does not apply - I will discuss recent suggestions of how to address the new data from the collisionless shock perspective. The backreaction of accelerated particles on the shock structure, its environment, and visibility across the electromagnetic spectrum from radio to gamma rays is another key aspect of collisionless shock that will be discussed.

Ultra-High Precision Half-Life Measurement for the Superallowed &+circ; Emitter ^26Al^m

NASA Astrophysics Data System (ADS)

Finlay, P.; Demand, G.; Garrett, P. E.; Leach, K. G.; Phillips, A. A.; Sumithrarachchi, C. S.; Svensson, C. E.; Triambak, S.; Ball, G. C.; Bandyopadhyay, D.; Djongolov, M.; Ettenauer, S.; Hackman, G.; Pearson, C. J.; Williams, S. J.; Andreoiu, C.; Cross, D.; Austin, R. A. E.; Grinyer, G. F.; Leslie, J. R.

2008-10-01

The calculated nuclear structure dependent correction for ^26Al^m (δC-δNS= 0.305(27)% [1]) is smaller by nearly a factor of two than the other twelve precision superallowed cases, making it an ideal case to pursue a reduction in the experimental errors contributing to the Ft value. An ultra-high precision half-life measurement for the superallowed &+circ; emitter ^26Al^m has been made using a 4π continuous gas flow proportional counter as part of an ongoing experimental program in superallowed Fermi β decay studies at the Isotope Separator and Accelerator (ISAC) facility at TRIUMF in Vancouver, Canada, which delivered a beam of ˜10^5 ^26Al^m/s in October 2007. With a statistical precision of ˜0.008%, the present work represents the single most precise measurement of any superallowed half-life to date. [1] I.S. Towner and J.C. Hardy, Phys. Rev. C 77, 025501 (2008).

Search for high-energy neutrinos from bright GRBs with ANTARES

NASA Astrophysics Data System (ADS)

Albert, A.; André, M.; Anghinolfi, M.; Anton, G.; Ardid, M.; Aubert, J.-J.; Avgitas, T.; Baret, B.; Barrios-Martí, J.; Basa, S.; Bertin, V.; Biagi, S.; Bormuth, R.; Bourret, S.; Bouwhuis, M. C.; Bruijn, R.; Brunner, J.; Busto, J.; Capone, A.; Caramete, L.; Carr, J.; Celli, S.; Chiarusi, T.; Circella, M.; Coelho, J. A. B.; Coleiro, A.; Coniglione, R.; Costantini, H.; Coyle, P.; Creusot, A.; Deschamps, A.; De Bonis, G.; Distefano, C.; di Palma, I.; Donzaud, C.; Dornic, D.; Drouhin, D.; Eberl, T.; El Bojaddaini, I.; Elsässer, D.; Enzenhöfer, A.; Felis, I.; Fusco, L. A.; Galatà, S.; Gay, P.; Geißelsöder, S.; Geyer, K.; Giordano, V.; Gleixner, A.; Glotin, H.; Gregoire, T.; Gracia-Ruiz, R.; Graf, K.; Hallmann, S.; van Haren, H.; Heijboer, A. J.; Hello, Y.; Hernández-Rey, J. J.; Hößl, J.; Hofestädt, J.; Hugon, C.; Illuminati, G.; James, C. W.; de Jong, M.; Jongen, M.; Kadler, M.; Kalekin, O.; Katz, U.; Kießling, D.; Kouchner, A.; Kreter, M.; Kreykenbohm, I.; Kulikovskiy, V.; Lachaud, C.; Lahmann, R.; Lefèvre, D.; Leonora, E.; Lotze, M.; Loucatos, S.; Marcelin, M.; Margiotta, A.; Marinelli, A.; Martínez-Mora, J. A.; Mathieu, A.; Mele, R.; Melis, K.; Michael, T.; Migliozzi, P.; Moussa, A.; Mueller, C.; Nezri, E.; Păvălaş, G. E.; Pellegrino, C.; Perrina, C.; Piattelli, P.; Popa, V.; Pradier, T.; Quinn, L.; Racca, C.; Riccobene, G.; Roensch, K.; Sánchez-Losa, A.; Saldaña, M.; Salvadori, I.; Samtleben, D. F. E.; Sanguineti, M.; Sapienza, P.; Schnabel, J.; Schüssler, F.; Seitz, T.; Sieger, C.; Spurio, M.; Stolarczyk, Th.; Taiuti, M.; Tayalati, Y.; Trovato, A.; Tselengidou, M.; Turpin, D.; Tönnis, C.; Vallage, B.; Vallée, C.; Van Elewyck, V.; Vivolo, D.; Vizzocca, A.; Wagner, S.; Wilms, J.; Zornoza, J. D.; Zúñiga, J.

2017-07-01

Gamma-ray bursts are thought to be sites of hadronic acceleration, thus neutrinos are expected from the decay of charged particles, produced in pγ interactions. The methods and results of a search for muon neutrinos in the data of the ANTARES neutrino telescope from four bright GRBs (GRB 080916C, GRB 110918A, GRB 130427A and GRB 130505A) observed between 2008 and 2013 are presented. Two scenarios of the fireball model have been investigated: the internal shock scenario, leading to the production of neutrinos with energies mainly above 100 TeV, and the photospheric scenario, characterized by a low-energy component in neutrino spectra due to the assumption of neutrino production closer to the central engine. Since no neutrino events have been detected in temporal and spatial coincidence with these bursts, upper limits at 90 per cent confidence level on the expected neutrino fluxes are derived. The non-detection allows for directly constraining the bulk Lorentz factor of the jet Γ and the baryon loading fp.

Analysis of the interaction between respiratory syncytial virus and lipid-rafts in Hep2 cells during infection

DOE Office of Scientific and Technical Information (OSTI.GOV)

Brown, Gaie; Jeffree, Chris E.; McDonald, Terence

2004-10-01

The assembly of respiratory syncytial virus (RSV) in lipid-rafts was examined in Hep2 cells. Confocal and electron microscopy showed that during RSV assembly, the cellular distribution of the complement regulatory proteins, decay accelerating factor (CD55) and CD59, changes and high levels of these cellular proteins are incorporated into mature virus filaments. The detergent-solubility properties of CD55, CD59, and the RSV fusion (F) protein were found to be consistent with each protein being located predominantly within lipid-raft structures. The levels of these proteins in cell-released virus were examined by immunoelectronmicroscopy and found to account for between 5% and 15% of themore » virus attachment (G) glycoprotein levels. Collectively, our findings suggest that an intimate association exists between RSV and lipid-raft membranes and that significant levels of these host-derived raft proteins, such as those regulating complement activation, are subsequently incorporated into the envelope of mature virus particles.« less

Workshop on Pion-Kaon Interactions (PKI2018) Mini-Proceedings

DOE Office of Scientific and Technical Information (OSTI.GOV)

Amaryan, M; Pal, Bilas

This volume is a short summary of talks given at the PKI2018 Workshop organized to discuss current status and future prospects of pi -K interactions. The precise data on pi K interaction will have a strong impact on strange meson spectroscopy and form factors that are important ingredients in the Dalitz plot analysis of a decays of heavy mesons as well as precision measurement of Vus matrix element and therefore on a test of unitarity in the first raw of the CKM matrix. The workshop has combined the efforts of experimentalists, Lattice QCD, and phenomenology communities. Experimental data relevant tomore » the topic of the workshop were presented from the broad range of different collaborations like CLAS, GlueX, COMPASS, BaBar, BELLE, BESIII, VEPP-2000, and LHCb. One of the main goals of this workshop was to outline a need for a new high intensity and high precision secondary KL beam facility at JLab produced with the 12 GeV electron beam of CEBAF accelerator.« less

Biexponential characterization of prostate tissue water diffusion decay curves over an extended b-factor range.

PubMed

Mulkern, Robert V; Barnes, Agnieszka Szot; Haker, Steven J; Hung, Yin P; Rybicki, Frank J; Maier, Stephan E; Tempany, Clare M C

2006-06-01

Detailed measurements of water diffusion within the prostate over an extended b-factor range were performed to assess whether the standard assumption of monoexponential signal decay is appropriate in this organ. From nine men undergoing prostate MR staging examinations at 1.5 T, a single 10-mm-thick axial slice was scanned with a line scan diffusion imaging sequence in which 14 equally spaced b factors from 5 to 3,500 s/mm(2) were sampled along three orthogonal diffusion sensitization directions in 6 min. Due to the combination of long scan time and limited volume coverage associated with the multi-b-factor, multidirectional sampling, the slice was chosen online from the available T2-weighted axial images with the specific goal of enabling the sampling of presumed noncancerous regions of interest (ROIs) within the central gland (CG) and peripheral zone (PZ). Histology from prescan biopsy (n=9) and postsurgical resection (n=4) was subsequently employed to help confirm that the ROIs sampled were noncancerous. The CG ROIs were characterized from the T2-weighted images as primarily mixtures of glandular and stromal benign prostatic hyperplasia, which is prevalent in this population. The water signal decays with b factor from all ROIs were clearly non-monoexponential and better served with bi- vs. monoexponential fits, as tested using chi(2)-based F test analyses. Fits to biexponential decay functions yielded intersubject fast diffusion component fractions in the order of 0.73+/-0.08 for both CG and PZ ROIs, fast diffusion coefficients of 2.68+/-0.39 and 2.52+/-0.38 microm(2)/ms and slow diffusion coefficients of 0.44+/-0.16 and 0.23+/-0.16 um(2)/ms for CG and PZ ROIs, respectively. The difference between the slow diffusion coefficients within CG and PZ was statistically significant as assessed with a Mann-Whitney nonparametric test (P<.05). We conclude that a monoexponential model for water diffusion decay in prostate tissue is inadequate when a large range of b factors is sampled and that biexponential analyses are better suited for characterizing prostate diffusion decay curves.

Accelerated Evolution and Functional Divergence of the Dim Light Visual Pigment Accompanies Cichlid Colonization of Central America.

PubMed

Hauser, Frances E; Ilves, Katriina L; Schott, Ryan K; Castiglione, Gianni M; López-Fernández, Hernán; Chang, Belinda S W

2017-10-01

Cichlids encompass one of the most diverse groups of fishes in South and Central America, and show extensive variation in life history, morphology, and colouration. While studies of visual system evolution in cichlids have focussed largely on the African rift lake species flocks, Neotropical cichlids offer a unique opportunity to investigate visual system evolution at broader temporal and geographic scales. South American cichlid colonization of Central America has likely promoted accelerated rates of morphological evolution in Central American lineages as they encountered reduced competition, renewed ecological opportunity, and novel aquatic habitats. To investigate whether such transitions have influenced molecular evolution of vision in Central American cichlids, we sequenced the dim-light rhodopsin gene in 101 Neotropical cichlid species, spanning the diversity of the clade. We find strong evidence for increased rates of evolution in Central American cichlid rhodopsin relative to South American lineages, and identify several sites under positive selection in rhodopsin that likely contribute to adaptation to different photic environments. We expressed a Neotropical cichlid rhodopsin protein invitro for the first time, and found that while its spectral tuning properties were characteristic of typical vertebrate rhodopsin pigments, the rate of decay of its active signalling form was much slower, consistent with dim light adaptation in other vertebrate rhodopsins. Using site-directed mutagenesis combined with spectroscopic assays, we found that a key amino acid substitution present in some Central American cichlids accelerates the rate of decay of active rhodopsin, which may mediate adaptation to clear water habitats. © The Author 2017. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Heart rate slopes during 6-min walk test in pulmonary arterial hypertension, other lung diseases, and healthy controls.

PubMed

Tonelli, Adriano R; Wang, Xiao-Feng; Alkukhun, Laith; Zhang, Qi; Dweik, Raed A; Minai, Omar A

2014-06-01

Six-minute walk test (6MWT) continues to be a useful tool to determine the functional capacity in patients with vascular and other lung diseases; nevertheless, it has a limited ability to predict prognosis in this context. We tested whether the heart rate (HR) acceleration and decay slopes during the 6-m walk test are different in patients with pulmonary arterial hypertension (PAH), other lung diseases, and healthy controls. In addition, we assessed whether the HR slopes are associated with clinical worsening. Using a portable, signal-morphology-based, impedance cardiograph (PhysioFlow Enduro, Paris, France) with real-time wireless monitoring via a Bluetooth USB adapter we determined beat-by-beat HR. We included 50 subjects in this pilot study, 20 with PAH (all on PAH-specific treatment), 17 with other lung diseases (obstructive [n = 12, 71%] or restrictive lung diseases [5, 29%]), and 13 healthy controls. The beat-by-beat HR curves were significantly different among all three groups of subjects either during the activity or recovery of the 6MWT. HR curves were less steep in PAH than the other two groups (P < 0.001). HR acceleration rates were slower in patients with PAH or other lung diseases with progression of their disease (P < 0.001). In conclusion, the acceleration and decay slopes during 6MWT are different among patients with PAH, other lung diseases, and healthy controls. The HR slopes during 6MWT were steeper in patients without clinical worsening. © 2014 The Authors. Physiological Reports published by Wiley Periodicals, Inc. on behalf of the American Physiological Society and The Physiological Society.

Underground neutrino detectors for particle and astroparticle Science: The Giant Liquid Argon Charge Imaging ExpeRiment (GLACIER)

NASA Astrophysics Data System (ADS)

Rubbia, André

2009-06-01

The current focus of the CERN program is the Large Hadron Collider (LHC), however, CERN is engaged in long baseline neutrino physics with the CNGS project and supports T2K as recognized CERN RE13, and for good reasons: a number of observed phenomena in high-energy physics and cosmology lack their resolution within the Standard Model of particle physics; these puzzles include the origin of neutrino masses, CP-violation in the leptonic sector, and baryon asymmetry of the Universe. They will only partially be addressed at LHC. A positive measurement of sin2 2θ13 > 0.01 would certainly give a tremendous boost to neutrino physics by opening the possibility to study CP violation in the lepton sector and the determination of the neutrino mass hierarchy with upgraded conventional super-beams. These experiments (so called 'Phase II') require, in addition to an upgraded beam power, next generation very massive neutrino detectors with excellent energy resolution and high detection efficiency in a wide neutrino energy range, to cover 1st and 2nd oscillation maxima, and excellent particle identification and p0 background suppression. Two generations of large water Cherenkov detectors at Kamioka (Kamiokande and Super-Kamiokande) have been extremely successful. And there are good reasons to consider a third generation water Cherenkov detector with an order of magnitude larger mass than Super-Kamiokande for both non-accelerator (proton decay, supernovae,...) and accelerator-based physics. On the other hand, a very massive underground liquid Argon detector of about 100 kton could represent a credible alternative for the precision measurements of 'Phase II' and aim at significantly new results in neutrino astroparticle and non-accelerator-based particle physics (e.g. proton decay).

Study of B c  → J/ψV and {B}_{c}^{* } \\rightarrow {\\eta }_{c}V decays within the QCD factorization

NASA Astrophysics Data System (ADS)

Chang, Qin; Chen, Li-Li; Xu, Shuai

2018-07-01

In this paper, we study the non-leptonic B c → J/ψV and {B}c* \\to {η }cV (V=ρ ,{K}* ) weak decays in the framework of QCD factorization. In the evaluation, the form factors are calculated using the Bauer–Stech–Wirbel model and the light-front quark model, respectively. Besides the longitudinal amplitude, the power-suppressed transverse contributions are also evaluated at next-to-leading order. The predictions for the observables of B c → J/ψV and {B}c* \\to {η }cV decays are presented. We find that the NLO QCD contribution presents about 8% correction to the branching ratios, and the longitudinal polarization fractions of these decays are at the level of (80 ∼ 90)%. In addition, we suggest direct measurements on some useful ratios, {R}{K* /ρ }(λ =0) and {\\widetilde{R}}{K* /ρ }(λ =0), which are very suitable to test the consistence between theoretical prediction and data because their theoretical uncertainties can be well controlled.

Gene Editing and Human Pluripotent Stem Cells: Tools for Advancing Diabetes Disease Modeling and Beta-Cell Development.

PubMed

Millette, Katelyn; Georgia, Senta

2017-10-05

This review will focus on the multiple approaches to gene editing and address the potential use of genetically modified human pluripotent stem cell-derived beta cells (SC-β) as a tool to study human beta-cell development and model their function in diabetes. We will explore how new variations of CRISPR/Cas9 gene editing may accelerate our understanding of beta-cell developmental biology, elucidate novel mechanisms that establish and regulate beta-cell function, and assist in pioneering new therapeutic modalities for treating diabetes. Improvements in CRISPR/Cas9 target specificity and homology-directed recombination continue to advance its use in engineering stem cells to model and potentially treat disease. We will review how CRISPR/Cas9 gene editing is informing our understanding of beta-cell development and expanding the therapeutic possibilities for treating diabetes and other diseases. Here we focus on the emerging use of gene editing technology, specifically CRISPR/Cas9, as a means of manipulating human gene expression to gain novel insights into the roles of key factors in beta-cell development and function. Taken together, the combined use of SC-β cells and CRISPR/Cas9 gene editing will shed new light on human beta-cell development and function and accelerate our progress towards developing new therapies for patients with diabetes.

[Tooth decay and associated factors among adolescents in the north of the State of Minas Gerais, Brazil: a hierarchical analysis].

PubMed

Silveira, Marise Fagundes; Freire, Rafael Silveira; Nepomuceno, Marcela Oliveira; Martins, Andréa Maria Eleutério de Barros Lima; Marcopito, Luiz Francisco

2015-11-01

This is a cross-sectional population-based study (n = 763) conducted in the north of the State of Minas Gerais, which aimed to investigate the prevalence of tooth decay among adolescents and to identify the potential determinants of same. Probability sampling by conglomerates in multiple stages was used. Trained and calibrated professionals performed the data collection by means of intraoral examination and interviews in the previously selected households. In the analysis of the determinant factor for the presence of tooth decay, hierarchical binary logistic regression models were used. The prevalence of tooth decay, decayed, missing and filled teeth were 71.3%, 36.5%, 55.6% and 16%, respectively. The following averages were observed: DMFT (3.4 teeth), number of decayed (0.8 teeth), restored (2.4 teeth) and missing (0.2 teeth). The incidence of tooth decay was higher among adolescents who stated they were black/indigenous/brown (OR = 1.76), lived in crowded households (OR = 2.4), did not regularly visit or had never been to a dentist (OR = 1.9), used public or philanthropic services (OR = 1,8), had smoking habits (OR = 4.1), consumed alcohol (OR = 1.8), perceived their oral health negatively (OR = 5.9 and OR = 1.9) and had toothac in the last six months (OR = 2.0).

The decay width of stringy hadrons

NASA Astrophysics Data System (ADS)

Sonnenschein, Jacob; Weissman, Dorin

2018-02-01

In this paper we further develop a string model of hadrons by computing their strong decay widths and comparing them to experiment. The main decay mechanism is that of a string splitting into two strings. The corresponding total decay width behaves as Γ = π/2 ATL where T and L are the tension and length of the string and A is a dimensionless universal constant. We show that this result holds for a bosonic string not only in the critical dimension. The partial width of a given decay mode is given by Γi / Γ =Φi exp ⁡ (- 2 πCmsep2 / T) where Φi is a phase space factor, msep is the mass of the "quark" and "antiquark" created at the splitting point, and C is a dimensionless coefficient close to unity. Based on the spectra of hadrons we observe that their (modified) Regge trajectories are characterized by a negative intercept. This implies a repulsive Casimir force that gives the string a "zero point length". We fit the theoretical decay width to experimental data for mesons on the trajectories of ρ, ω, π, η, K*, ϕ, D, and Ds*, and of the baryons N, Δ, Λ, and Σ. We examine both the linearity in L and the exponential suppression factor. The linearity was found to agree with the data well for mesons but less for baryons. The extracted coefficient for mesons A = 0.095 ± 0.015 is indeed quite universal. The exponential suppression was applied to both strong and radiative decays. We discuss the relation with string fragmentation and jet formation. We extract the quark-diquark structure of baryons from their decays. A stringy mechanism for Zweig suppressed decays of quarkonia is proposed and is shown to reproduce the decay width of ϒ states. The dependence of the width on spin and flavor symmetry is discussed. We further apply this model to the decays of glueballs and exotic hadrons.

Stabilization of diastolic calcium signal via calcium pump regulation of complex local calcium releases and transient decay in a computational model of cardiac pacemaker cell with individual release channels

PubMed Central

Maltsev, Alexander V.; Maltsev, Victor A.; Stern, Michael D.

2017-01-01

Intracellular Local Ca releases (LCRs) from sarcoplasmic reticulum (SR) regulate cardiac pacemaker cell function by activation of electrogenic Na/Ca exchanger (NCX) during diastole. Prior studies demonstrated the existence of powerful compensatory mechanisms of LCR regulation via a complex local cross-talk of Ca pump, release and NCX. One major obstacle to study these mechanisms is that LCR exhibit complex Ca release propagation patterns (including merges and separations) that have not been characterized. Here we developed new terminology, classification, and computer algorithms for automatic detection of numerically simulated LCRs and examined LCR regulation by SR Ca pumping rate (Pup) that provides a major contribution to fight-or-flight response. In our simulations the faster SR Ca pumping accelerates action potential-induced Ca transient decay and quickly clears Ca under the cell membrane in diastole, preventing premature releases. Then the SR generates an earlier, more synchronized, and stronger diastolic LCR signal activating an earlier and larger inward NCX current. LCRs at higher Pup exhibit larger amplitudes and faster propagation with more collisions to each other. The LCRs overlap with Ca transient decay, causing an elevation of the average diastolic [Ca] nadir to ~200 nM (at Pup = 24 mM/s). Background Ca (in locations lacking LCRs) quickly decays to resting Ca levels (<100 nM) at high Pup, but remained elevated during slower decay at low Pup. Release propagation is facilitated at higher Pup by a larger LCR amplitude, whereas at low Pup by higher background Ca. While at low Pup LCRs show smaller amplitudes, their larger durations and sizes combined with longer transient decay stabilize integrals of diastolic Ca and NCX current signals. Thus, the local interplay of SR Ca pump and release channels regulates LCRs and Ca transient decay to insure fail-safe pacemaker cell operation within a wide range of rates. PMID:28792496