WorldWideScience

Sample records for reversible quiescence state

  1. High Runx1 Levels Promote a Reversible, More-Differentiated Cell State in Hair-Follicle Stem Cells during Quiescence

    Directory of Open Access Journals (Sweden)

    Song Eun Lee

    2014-02-01

    Full Text Available Quiescent hair follicle (HF bulge stem cells (SCs differentiate to early progenitor (EP hair germ (HG cells, which divide to produce transit-amplifying matrix cells. EPs can revert to SCs upon injury, but whether this dedifferentiation occurs in normal HF homeostasis (hair cycle and the mechanisms regulating both differentiation and dedifferentiation are unclear. Here, we use lineage tracing, gain of function, transcriptional profiling, and functional assays to examine the role of observed endogenous Runx1 level changes in the hair cycle. We find that forced Runx1 expression induces hair degeneration (catagen and simultaneously promotes changes in the quiescent bulge SC transcriptome toward a cell state resembling the EP HG fate. This cell-state transition is functionally reversible. We propose that SC differentiation and dedifferentiation are likely to occur during normal HF degeneration and niche restructuring in response to changes in endogenous Runx1 levels associated with SC location with respect to the niche.

  2. Reversible Age-Related Phenotypes Induced during Larval Quiescence in C. elegans.

    Science.gov (United States)

    Roux, Antoine E; Langhans, Kelley; Huynh, Walter; Kenyon, Cynthia

    2016-06-14

    Cells can enter quiescent states in which cell cycling and growth are suspended. We find that during a long developmental arrest (quiescence) induced by starvation, newly hatched C. elegans acquire features associated with impaired proteostasis and aging: mitochondrial fission, ROS production, protein aggregation, decreased proteotoxic-stress resistance, and at the organismal level, decline of mobility and high mortality. All signs of aging but one, the presence of protein aggregates, were reversed upon return to development induced by feeding. The endoplasmic reticulum receptor IRE-1 is completely required for recovery, and the downstream transcription factor XBP-1, as well as a protein kinase, KGB-1, are partially required. Interestingly, kgb-1(-) mutants that do recover fail to reverse aging-like mitochondrial phenotypes and have a short adult lifespan. Our study describes the first pathway that reverses phenotypes of aging at the exit of prolonged quiescence.

  3. Distinct Mechanisms Underlie Quiescence during Two Caenorhabditis elegans Sleep-Like States.

    Science.gov (United States)

    Trojanowski, Nicholas F; Nelson, Matthew D; Flavell, Steven W; Fang-Yen, Christopher; Raizen, David M

    2015-10-28

    Electrophysiological recordings have enabled identification of physiologically distinct yet behaviorally similar states of mammalian sleep. In contrast, sleep in nonmammals has generally been identified behaviorally and therefore regarded as a physiologically uniform state characterized by quiescence of feeding and locomotion, reduced responsiveness, and rapid reversibility. The nematode Caenorhabditis elegans displays sleep-like quiescent behavior under two conditions: developmentally timed quiescence (DTQ) occurs during larval transitions, and stress-induced quiescence (SIQ) occurs in response to exposure to cellular stressors. Behaviorally, DTQ and SIQ appear identical. Here, we use optogenetic manipulations of neuronal and muscular activity, pharmacology, and genetic perturbations to uncover circuit and molecular mechanisms of DTQ and SIQ. We find that locomotion quiescence induced by DTQ- and SIQ-associated neuropeptides occurs via their action on the nervous system, although their neuronal target(s) and/or molecular mechanisms likely differ. Feeding quiescence during DTQ results from a loss of pharyngeal muscle excitability, whereas feeding quiescence during SIQ results from a loss of excitability in the nervous system. Together these results indicate that, as in mammals, quiescence is subserved by different mechanisms during distinct sleep-like states in C. elegans.

  4. Distinct Mechanisms Underlie Quiescence during Two Caenorhabditis elegans Sleep-Like States

    OpenAIRE

    Trojanowski, Nicholas F.; Nelson, Matthew D.; Flavell, Steven W.; Fang-Yen, Christopher; Raizen, David M.

    2015-01-01

    Electrophysiological recordings have enabled identification of physiologically distinct yet behaviorally similar states of mammalian sleep. In contrast, sleep in nonmammals has generally been identified behaviorally and therefore regarded as a physiologically uniform state characterized by quiescence of feeding and locomotion, reduced responsiveness, and rapid reversibility. The nematode Caenorhabditis elegans displays sleep-like quiescent behavior under two conditions: developmentally timed ...

  5. Concise Review: Quiescence in Adult Stem Cells

    DEFF Research Database (Denmark)

    Rumman, M; Dhawan, J; Kassem, Moustapha

    2015-01-01

    Adult stem cells (ASCs) are tissue resident stem cells responsible for tissue homeostasis and regeneration following injury. In uninjured tissues, ASCs exist in a nonproliferating, reversibly cell cycle-arrested state known as quiescence or G0. A key function of the quiescent state is to preserve...... stemness in ASCs by preventing precocious differentiation, and thus maintaining a pool of undifferentiated ASCs. Recent evidences suggest that quiescence is an actively maintained state and that excessive or defective quiescence may lead to compromised tissue regeneration or tumorigenesis. The aim...

  6. Concise Review: Quiescence in Adult Stem Cells: Biological Significance and Relevance to Tissue Regeneration.

    Science.gov (United States)

    Rumman, Mohammad; Dhawan, Jyotsna; Kassem, Moustapha

    2015-10-01

    Adult stem cells (ASCs) are tissue resident stem cells responsible for tissue homeostasis and regeneration following injury. In uninjured tissues, ASCs exist in a nonproliferating, reversibly cell cycle-arrested state known as quiescence or G0. A key function of the quiescent state is to preserve stemness in ASCs by preventing precocious differentiation, and thus maintaining a pool of undifferentiated ASCs. Recent evidences suggest that quiescence is an actively maintained state and that excessive or defective quiescence may lead to compromised tissue regeneration or tumorigenesis. The aim of this review is to provide an update regarding the biological mechanisms of ASC quiescence and their role in tissue regeneration.

  7. Cellular quiescence in mammary stem cells and breast tumor stem cells: got testable hypotheses?

    Science.gov (United States)

    Harmes, David C; DiRenzo, James

    2009-03-01

    Cellular quiescence is a state of reversible cell cycle arrest and has more recently been shown to be a blockade to differentiation and to correlate with resistance to cancer chemotherapeutics and other xenobiotics; features that are common to adult stem cells and possibly tumor stem cells. The biphasic kinetics of mammary regeneration, coupled to its cyclic endocrine control suggest that mammary stem cells most likely divide during a narrow window of the regenerative cycle and return to a state of quiescence. This would enable them to retain their proliferative capacity, resist differentiation signals and preserve their prolonged life span. There is accumulating evidence that mammary stem cells and other adult stem cells utilize quiescence for this purpose, however the degree to which tumor stem cells do so is largely unknown. The retained proliferative capacity of mammary stem cells likely enables them to accumulate and harbor mutations that lead to breast cancer initiation. However it is currently unclear if these causative lesions lead to defective or deranged quiescence in mammary stem cells. Evidence of such effects could potentially lead to the development of diagnostic systems that monitor mammary stem cell quiescence or activation. Such systems may be useful for the evaluation of patients who are at significant risk of breast cancer. Additionally quiescence has been postulated to contribute to therapeutic resistance and tumor recurrence. This review aims to evaluate what is known about the mechanisms governing cellular quiescence and the role of tumor stem cell quiescence in breast cancer recurrence.

  8. Proliferation/quiescence: the controversial "aller-retour"

    Directory of Open Access Journals (Sweden)

    Sagot Isabelle

    2011-05-01

    Full Text Available Abstract The vast majority of cells, from prokaryotes up to vertebrate organisms, spend most of their time in quiescence, a state defined as a temporary and reversible absence of proliferation. Establishing the quiescent state while maintaining the capacity to re-enter the proliferation cycle are critical for cell survival and must be tightly orchestrated to avoid pathological proliferation. Hence, studying the biology of quiescent cells is an exciting research field. Taking advantage of technical progress in genomic, transcriptomic and metabolomic, the nature of transitions between proliferation and quiescence have been recently re-visited in budding yeast. Together with new findings in cell biology, these studies resuscitate an old demon in the field: the controversial existence of a "quiescence program".

  9. The microRNA miR-235 couples blast-cell quiescence to the nutritional state.

    Science.gov (United States)

    Kasuga, Hidefumi; Fukuyama, Masamitsu; Kitazawa, Aya; Kontani, Kenji; Katada, Toshiaki

    2013-05-23

    The coordination of stem- and blast-cell behaviours, such as self-renewal, differentiation and quiescence, with physiological changes underlies growth, regeneration and tissue homeostasis. Germline stem and somatic blast cells in newly hatched Caenorhabditis elegans larvae can suspend postembryonic development, which consists of diverse cellular events such as migration, proliferation and differentiation, until the nutritional state becomes favourable (termed L1 diapause). Although previous studies showed that the insulin/insulin-like growth factor (IGF) signalling (IIS) pathway regulates this developmental quiescence, the detailed mechanism by which the IIS pathway enables these multipotent cells to respond to nutrient availability is unknown. Here we show in C. elegans that the microRNA (miRNA) miR-235, a sole orthologue of mammalian miR-92 from the oncogenic miR-17-92 cluster, acts in the hypodermis and glial cells to arrest postembryonic developmental events in both neuroblasts and mesoblasts. Expression of mir-235 persists during L1 diapause, and decreases upon feeding in a manner dependent on the IIS pathway. Upregulation of one of the miR-235 targets, nhr-91, which encodes an orthologue of mammalian germ cell nuclear factor, is responsible for defects caused by loss of the miRNA. Our findings establish a novel role of a miR-92 orthologue in coupling blast-cell behaviours to the nutritional state.

  10. ASI regulates satiety quiescence in C. elegans.

    Science.gov (United States)

    Gallagher, Thomas; Kim, Jeongho; Oldenbroek, Marieke; Kerr, Rex; You, Young-Jai

    2013-06-05

    In Caenorhabditis elegans, satiety quiescence mimics behavioral aspects of satiety and postprandial sleep in mammals. On the basis of calcium-imaging, genetics, and behavioral studies, here we report that a pair of amphid neurons, ASI, is activated by nutrition and regulates worms' behavioral states specifically promoting satiety quiescence; ASI inhibits the switch from quiescence to dwelling (a browsing state) and accelerates the switch from dwelling to quiescence. The canonical TGFβ pathway, whose ligand is released from ASI, regulates satiety quiescence. The mutants of a ligand, a receptor and SMADs in the TGFβ pathway all eat more and show less quiescence than wild-type. The TGFβ receptor in downstream neurons RIM and RIC is sufficient for worms to exhibit satiety quiescence, suggesting neuronal connection from ASI to RIM and RIC is essential for feeding regulation through the TGFβ pathway. ASI also regulates satiety quiescence partly through cGMP signaling; restoring cGMP signaling in ASI rescues the satiety quiescence defect of cGMP signaling mutants. From these results, we propose that TGFβ and cGMP pathways in ASI connect nutritional status to promotion of satiety quiescence, a sleep-like behavioral state.

  11. A gene-trap strategy identifies quiescence-induced genes in synchronized myoblasts

    Indian Academy of Sciences (India)

    Ramkumar Sambasivan; Grace K Pavlath; Jyotsna Dhawan

    2008-03-01

    Cellular quiescence is characterized not only by reduced mitotic and metabolic activity but also by altered gene expression. Growing evidence suggests that quiescence is not merely a basal state but is regulated by active mechanisms. To understand the molecular programme that governs reversible cell cycle exit, we focused on quiescence-related gene expression in a culture model of myogenic cell arrest and activation. Here we report the identification of quiescence-induced genes using a gene-trap strategy. Using a retroviral vector, we generated a library of gene traps in C2C12 myoblasts that were screened for arrest-induced insertions by live cell sorting (FACS-gal). Several independent genetrap lines revealed arrest-dependent induction of gal activity, confirming the efficacy of the FACS screen. The locus of integration was identified in 15 lines. In three lines, insertion occurred in genes previously implicated in the control of quiescence, i.e. EMSY – a BRCA2-interacting protein, p8/com1– a p300HAT-binding protein and MLL5 – a SET domain protein. Our results demonstrate that expression of chromatin modulatory genes is induced in G0, providing support to the notion that this reversibly arrested state is actively regulated.

  12. Sperm quiescence in cauda epididymis: a mini-review

    Institute of Scientific and Technical Information of China (English)

    Ramtej Jayram Verma

    2001-01-01

    The concentration of sodium chloride is of prime importance in the initiation and reversal of sperm quiescence in the cauda epididymis. Other factors such as inorganic and organic constituents of the luminal fluid are of secondary importance and might assist in inducing sperm quiescence.

  13. Black Hole Binaries in Quiescence

    CERN Document Server

    Bailyn, Charles D

    2016-01-01

    I discuss some of what is known and unknown about the behavior of black hole binary systems in the quiescent accretion state. Quiescence is important for several reasons: 1) the dominance of the companion star in the optical and IR wavelengths allows the binary parameters to be robustly determined - as an example, we argue that the longer proposed distance to the X-ray source GRO J1655-40 is correct; 2) quiescence represents the limiting case of an extremely low accretion rate, in which both accretion and jets can be observed; 3) understanding the evolution and duration of the quiescent state is a key factor in determining the overall demographics of X-rary binaries, which has taken on a new importance in the era of gravitational wave astronomy.

  14. Predicting trend reversals using market instantaneous state

    Science.gov (United States)

    Bury, Thomas

    2014-06-01

    Collective behaviors taking place in financial markets reveal strongly correlated states especially during a crisis period. A natural hypothesis is that trend reversals are also driven by mutual influences between the different stock exchanges. Using a maximum entropy approach, we find coordinated behavior during trend reversals dominated by the pairwise component. In particular, these events are predicted with high significant accuracy by the ensemble's instantaneous state.

  15. Global Promoter Targeting of a Conserved Lysine Deacetylase for Transcriptional Shutoff during Quiescence Entry.

    Science.gov (United States)

    McKnight, Jeffrey N; Boerma, Joseph W; Breeden, Linda L; Tsukiyama, Toshio

    2015-09-01

    Quiescence is a conserved cell-cycle state characterized by cell-cycle arrest, increased stress resistance, enhanced longevity, and decreased transcriptional, translational, and metabolic output. Although quiescence plays essential roles in cell survival and normal differentiation, the molecular mechanisms leading to this state are not well understood. Here, we determined changes in the transcriptome and chromatin structure of S. cerevisiae upon quiescence entry. Our analyses revealed transcriptional shutoff that is far more robust than previously believed and an unprecedented global chromatin transition, which are tightly correlated. These changes require Rpd3 lysine deacetylase targeting to at least half of gene promoters via quiescence-specific transcription factors including Xbp1 and Stb3. Deletion of RPD3 prevents cells from establishing transcriptional quiescence, leading to defects in quiescence entry and shortening of chronological lifespan. Our results define a molecular mechanism for global reprogramming of transcriptome and chromatin structure for quiescence driven by a highly conserved chromatin regulator.

  16. Cell-cycle quiescence maintains Caenorhabditis elegans germline stem cells independent of GLP-1/Notch.

    Science.gov (United States)

    Seidel, Hannah S; Kimble, Judith

    2015-11-09

    Many types of adult stem cells exist in a state of cell-cycle quiescence, yet it has remained unclear whether quiescence plays a role in maintaining the stem cell fate. Here we establish the adult germline of Caenorhabditis elegans as a model for facultative stem cell quiescence. We find that mitotically dividing germ cells--including germline stem cells--become quiescent in the absence of food. This quiescence is characterized by a slowing of S phase, a block to M-phase entry, and the ability to re-enter M phase rapidly in response to re-feeding. Further, we demonstrate that cell-cycle quiescence alters the genetic requirements for stem cell maintenance: The signaling pathway required for stem cell maintenance under fed conditions--GLP-1/Notch signaling--becomes dispensable under conditions of quiescence. Thus, cell-cycle quiescence can itself maintain stem cells, independent of the signaling pathway otherwise essential for such maintenance.

  17. Distinct transcriptional networks in quiescent myoblasts: a role for Wnt signaling in reversible vs. irreversible arrest.

    Science.gov (United States)

    Subramaniam, Sindhu; Sreenivas, Prethish; Cheedipudi, Sirisha; Reddy, Vatrapu Rami; Shashidhara, Lingadahalli Subrahmanya; Chilukoti, Ravi Kumar; Mylavarapu, Madhavi; Dhawan, Jyotsna

    2014-01-01

    Most cells in adult mammals are non-dividing: differentiated cells exit the cell cycle permanently, but stem cells exist in a state of reversible arrest called quiescence. In damaged skeletal muscle, quiescent satellite stem cells re-enter the cell cycle, proliferate and subsequently execute divergent programs to regenerate both post-mitotic myofibers and quiescent stem cells. The molecular basis for these alternative programs of arrest is poorly understood. In this study, we used an established myogenic culture model (C2C12 myoblasts) to generate cells in alternative states of arrest and investigate their global transcriptional profiles. Using cDNA microarrays, we compared G0 myoblasts with post-mitotic myotubes. Our findings define the transcriptional program of quiescent myoblasts in culture and establish that distinct gene expression profiles, especially of tumour suppressor genes and inhibitors of differentiation characterize reversible arrest, distinguishing this state from irreversibly arrested myotubes. We also reveal the existence of a tissue-specific quiescence program by comparing G0 C2C12 myoblasts to isogenic G0 fibroblasts (10T1/2). Intriguingly, in myoblasts but not fibroblasts, quiescence is associated with a signature of Wnt pathway genes. We provide evidence that different levels of signaling via the canonical Wnt pathway characterize distinct cellular states (proliferation vs. quiescence vs. differentiation). Moderate induction of Wnt signaling in quiescence is associated with critical properties such as clonogenic self-renewal. Exogenous Wnt treatment subverts the quiescence program and negatively affects clonogenicity. Finally, we identify two new quiescence-induced regulators of canonical Wnt signaling, Rgs2 and Dkk3, whose induction in G0 is required for clonogenic self-renewal. These results support the concept that active signal-mediated regulation of quiescence contributes to stem cell properties, and have implications for pathological

  18. Adenovirus infection reverses the antiviral state induced by human interferon.

    Science.gov (United States)

    Feduchi, E; Carrasco, L

    1987-04-06

    HeLa cells treated with human lymphoblastoid interferon do not synthesize poliovirus proteins. The antiviral state against poliovirus is reversed if cells are previously infected with adenovirus type 5. A late gene product seems to be involved in this reversion, since no effect is observed at early stages of infection or in the presence of aphidicolin.

  19. Epidermal growth factor signaling induces behavioral quiescence in Caenorhabditis elegans.

    Science.gov (United States)

    Van Buskirk, Cheryl; Sternberg, Paul W

    2007-10-01

    The epidermal growth factor receptor (EGFR)/ErbB receptor tyrosine kinases regulate several aspects of development, including the development of the mammalian nervous system. ErbB signaling also has physiological effects on neuronal function, with influences on synaptic plasticity and daily cycles of activity. However, little is known about the effectors of EGFR activation in neurons. Here we show that EGF signaling has a nondevelopmental effect on behavior in Caenorhabditis elegans. Ectopic expression of the EGF-like ligand LIN-3 at any stage induces a reversible cessation of feeding and locomotion. These effects are mediated by neuronal EGFR (also called LET-23) and phospholipase C-gamma (PLC-gamma), diacylglycerol-binding proteins, and regulators of synaptic vesicle release. Activation of EGFR within a single neuron, ALA, is sufficient to induce a quiescent state. This pathway modulates the cessation of pharyngeal pumping and locomotion that normally occurs during the lethargus period that precedes larval molting. Our results reveal an evolutionarily conserved role for EGF signaling in the regulation of behavioral quiescence.

  20. The dual effects of root-cap exudates on nematodes: from quiescence in plant-parasitic nematodes to frenzy in entomopathogenic nematodes.

    Science.gov (United States)

    Hiltpold, Ivan; Jaffuel, Geoffrey; Turlings, Ted C J

    2015-02-01

    To defend themselves against herbivores and pathogens, plants produce numerous secondary metabolites, either constitutively or de novo in response to attacks. An intriguing constitutive example is the exudate produced by certain root-cap cells that can induce a state of reversible quiescence in plant-parasitic nematodes, thereby providing protection against these antagonists. The effect of such root exudates on beneficial entomopathogenic nematodes (EPNs) remains unclear, but could potentially impair their use in pest management programmes. We therefore tested how the exudates secreted by green pea (Pisum sativum) root caps affect four commercial EPN species. The exudates induced reversible quiescence in all EPN species tested. Quiescence levels varied with the green pea cultivars tested. Notably, after storage in root exudate, EPN performance traits were maintained over time, whereas performances of EPNs stored in water rapidly declined. In sharp contrast to high concentrations, lower concentrations of the exudate resulted in a significant increase in EPN activity and infectiousness, but still reduced the activity of two plant-parasitic nematode species. Our study suggests a finely tuned dual bioactivity of the exudate from green pea root caps. Appropriately formulated, it can favour long-term storage of EPNs and boost their infectiousness, while it may also be used to protect plants from plant-parasitic nematodes.

  1. Discrimination of mixed quantum states. Reversible maps and unambiguous strategies

    Energy Technology Data Exchange (ETDEWEB)

    Kleinmann, Matthias

    2008-06-30

    commutators and allows an explicit construction of the (2 x 2)-dimensional blocks. As an important application of unambiguous state discrimination, unambiguous state comparison, i.e., the question whether two states are identical or not, is generalized and optimal measurements for this problem are constructed. If for a certain family of states, a physical device maps the input state to an output state, such that a second device can be built that yields back the original input state, such a map is called reversible on this family. With respect to state discrimination, such reversible maps are particularly interesting, if the output states are pure. A complete characterization of all families that allow such a reversible and purifying map is provided. If the states are mapped to pure states, but the map itself is not reversible, upper and lower bounds are analyzed for the ''deviation from perfect faithfulness'', a quantity which measures the deviation from a reversible mapping. (orig.)

  2. Megakaryocytes regulate hematopoietic stem cell quiescence via Cxcl4 secretion

    Science.gov (United States)

    Bruns, Ingmar; Lucas, Daniel; Pinho, Sandra; Ahmed, Jalal; Lambert, Michele P.; Kunisaki, Yuya; Scheiermann, Christoph; Schiff, Lauren; Poncz, Mortimer; Bergman, Aviv; Frenette, Paul S.

    2014-01-01

    In the bone marrow (BM), hematopoietic stem cells (HSCs) lodge in specialized microenvironments that tightly control their proliferative state to adapt to the varying needs for replenishment of blood cells while also preventing exhaustion1. All putative niche cells suggested thus far have a non-hematopoietic origin2-8. Thus, it remains unclear how feedback from mature cells is conveyed to HSCs to adjust proliferation. Here we show that megakaryocytes (Mk) can directly regulate HSC pool size. Three-dimensional whole-mount imaging revealed that endogenous HSCs are frequently located adjacent to Mk in a non-random fashion. Selective in vivo depletion of Mk resulted in specific loss of HSC quiescence and led to a marked expansion of functional HSCs. Gene expression analyses revealed that Mk were the source of chemokine C-X-C motif ligand 4 (Cxcl4, also named platelet factor 4, Pf4) in the BM and Cxcl4 injection reduced HSC numbers via increased quiescence. By contrast, Cxcl4−/− mice exhibited increased HSC numbers and proliferation. Combined use of whole-mount imaging and computational modelling was highly suggestive of a megakaryocytic niche capable of influencing independently HSC maintenance by regulating quiescence. Thus, these results indicate that a terminally differentiated HSC progeny contributes to niche activity by directly regulating HSC behavior. PMID:25326802

  3. Wetting reversal at gelation transition freezes thermodynamically unstable states.

    Science.gov (United States)

    Hirayama, Shinya; Sano, Masahito

    2013-07-23

    The contact angle of a drop of gelling solution on a flat, solid surface was monitored as the hot solution was allowed to cool. When a solvent with a high cohesive energy and a wettable solid surface was used, a wetting solution turned into a dewetting solid at the gelation transition. The density profiles in gel as probed by confocal Raman microscopy reveal that the adsorption of both gelator and solvent shifts at the transition and the solvent is severely depleted from the interfacial region. Thus, the wetting reversal is accompanied by the interfacial desolvation. As a result of the adsorption shift during the gelation process in progress, a locally concentrated region of the gelator is frozen in space far away from the surface. This is a thermodynamically unstable state but can be realized reproducibly. The profile analysis also shows that the effect of the surface extends out to a few hundred micrometers, 2 orders of magnitude larger than the bulk correlation length.

  4. Quiescence: early evolutionary origins and universality do not imply uniformity.

    Science.gov (United States)

    O'Farrell, Patrick H

    2011-12-27

    Cell cycle investigations have focused on relentless exponential proliferation of cells, an unsustainable situation in nature. Proliferation of cells, whether microbial or metazoan, is interrupted by periods of quiescence. The vast majority of cells in an adult metazoan lie quiescent. As disruptions in this quiescence are at the foundation of cancer, it will be important for the field to turn its attention to the mechanisms regulating quiescence. While often presented as a single topic, there are multiple forms of quiescence each with complex inputs, some of which are tied to conceptually challenging aspects of metazoan regulation such as size control. In an effort to expose the enormity of the challenge, I describe the differing biological purposes of quiescence, and the coupling of quiescence in metazoans to growth and to the structuring of tissues during development. I emphasize studies in the organism rather than in tissue culture, because these expose the diversity of regulation. While quiescence is likely to be a primitive biological process, it appears that in adapting quiescence to its many distinct biological settings, evolution has diversified it. Consideration of quiescence in different models gives us an overview of this diversity.

  5. Assessing the likelihood and magnitude of volcanic explosions based on seismic quiescence

    Science.gov (United States)

    Roman, Diana C.; Rodgers, Mel; Geirsson, Halldor; LaFemina, Peter C.; Tenorio, Virginia

    2016-09-01

    Volcanic eruptions are generally forecast based on strong increases in monitoring parameters such as seismicity or gas emissions above a relatively low background level (e.g., Voight, 1988; Sparks, 2003). Because of this, forecasting individual explosions during an ongoing eruption, or at persistently restless volcanoes, is difficult as seismicity, gas emissions, and other indicators of unrest are already in a heightened state. Therefore, identification of short-term precursors to individual explosions at volcanoes already in heightened states of unrest, and an understanding of explosion trigger mechanisms, is important for the reduction of volcanic risk worldwide. Seismic and visual observations at Telica Volcano, Nicaragua, demonstrate that a) episodes of seismic quiescence reliably preceded explosions during an eruption in May 2011 and b) the duration of precursory quiescence and the energy released in the ensuing explosion were strongly correlated. Precursory seismic quiescence is interpreted as the result of sealing of shallow gas pathways, leading to pressure accumulation and eventual catastrophic failure of the system, culminating in an explosion. Longer periods of sealing and pressurization lead to greater energy release in the ensuing explosion. Near-real-time observations of seismic quiescence at restless or erupting volcanoes can thus be useful for both timely eruption warnings and for forecasting the energy of impending explosions.

  6. Diapause and quiescence in Lutzomyia diabolica (Diptera:Psychodidae).

    Science.gov (United States)

    Lawyer, P; Young, D

    1991-12-01

    Gravid, laboratory-reared Lutzomyia diabolica from Garner State Park, Texas, oviposited from May to December in an outdoor colony cage at Gainesville, Florida. Egg batches contained 100% fast-developing (nondiapause) eggs, a mixture of fast-developing and slow-developing (diapause) eggs, or 100% slow-developing eggs, depending on the time of year laid. The percent diapause eggs per batch increased from 0% in early October to 100% by December. These observations suggest that Lu. diabolica is a long-day species, depositing diapause eggs in response to shorter day length. Temperature may also modify the degree of diapause response by altering the calendar position of the critical day length. Termination of the winter diapause is probably temperature dependent. Quiescence was observed in 3rd and 4th stage larvae in both indoor and outdoor cultures and was usually associated with adverse conditions such as excessive moisture, extreme temperatures, or poor diet.

  7. The Saccharomyces cerevisiae protein Stm1p facilitates ribosome preservation during quiescence

    Energy Technology Data Exchange (ETDEWEB)

    Van Dyke, Natalya; Chanchorn, Ekkawit [Department of Chemistry and Physics, Western Carolina University, 111 Memorial Drive, Cullowhee, NC 28723 (United States); Van Dyke, Michael W., E-mail: mvandyke@email.wcu.edu [Department of Chemistry and Physics, Western Carolina University, 111 Memorial Drive, Cullowhee, NC 28723 (United States)

    2013-01-11

    Highlights: Black-Right-Pointing-Pointer Stm1p confers increased resistance to the macrolide starvation-mimic rapamycin. Black-Right-Pointing-Pointer Stm1p maintains 80S ribosome integrity during stationary phase-induced quiescence. Black-Right-Pointing-Pointer Stm1p facilitates polysome formation following quiescence exit. Black-Right-Pointing-Pointer Stm1p facilitates protein synthesis following quiescence exit. Black-Right-Pointing-Pointer Stm1p is a ribosome preservation factor under conditions of nutrient deprivation. -- Abstract: Once cells exhaust nutrients from their environment, they enter an alternative resting state known as quiescence, whereby proliferation ceases and essential nutrients are obtained through internal stores and through the catabolism of existing macromolecules and organelles. One example of this is ribophagy, the degradation of ribosomes through the process of autophagy. However, some ribosomes need to be preserved for an anticipated recovery from nutrient deprivation. We found that the ribosome-associated protein Stm1p greatly increases the quantity of 80S ribosomes present in quiescent yeast cells and that these ribosomes facilitate increased protein synthesis rates once nutrients are restored. These findings suggest that Stm1p can act as a ribosome preservation factor under conditions of nutrient deprivation and restoration.

  8. Arteriolar niches maintain haematopoietic stem cell quiescence

    Science.gov (United States)

    Kunisaki, Yuya; Bruns, Ingmar; Scheiermann, Christoph; Ahmed, Jalal; Pinho, Sandra; Zhang, Dachuan; Mizoguchi, Toshihide; Wei, Qiaozhi; Lucas, Daniel; Ito, Keisuke; Mar, Jessica C.; Bergman, Aviv; Frenette, Paul S.

    2013-01-01

    Cell cycle quiescence is a critical feature contributing to haematopoietic stem cell (HSC) maintenance. Although various candidate stromal cells have been identified as potential HSC niches, the spatial localization of quiescent HSCs in the bone marrow (BM) remains unclear. Here, using a novel approach that combines whole-mount confocal immunofluorescence imaging techniques and computational modelling to analyse significant tridimensional associations among vascular structures, stromal cells and HSCs, we show that quiescent HSCs associate specifically with small arterioles that are preferentially found in endosteal BM. These arterioles are ensheathed exclusively by rare NG2+ pericytes, distinct from sinusoid-associated LepR+ cells. Pharmacological or genetic activation of HSC cell cycle alters the distribution of HSCs from NG2+ peri-arteriolar niches to LepR+ peri-sinusoidal niches. Conditional depletion of NG2+ cells induces HSC cycling and reduces functional long-term repopulating HSCs in BM. These results thus indicate that arteriolar niches are indispensable to maintain HSC quiescence. PMID:24107994

  9. Arteriolar niches maintain haematopoietic stem cell quiescence.

    Science.gov (United States)

    Kunisaki, Yuya; Bruns, Ingmar; Scheiermann, Christoph; Ahmed, Jalal; Pinho, Sandra; Zhang, Dachuan; Mizoguchi, Toshihide; Wei, Qiaozhi; Lucas, Daniel; Ito, Keisuke; Mar, Jessica C; Bergman, Aviv; Frenette, Paul S

    2013-10-31

    Cell cycle quiescence is a critical feature contributing to haematopoietic stem cell (HSC) maintenance. Although various candidate stromal cells have been identified as potential HSC niches, the spatial localization of quiescent HSCs in the bone marrow remains unclear. Here, using a novel approach that combines whole-mount confocal immunofluorescence imaging techniques and computational modelling to analyse significant three-dimensional associations in the mouse bone marrow among vascular structures, stromal cells and HSCs, we show that quiescent HSCs associate specifically with small arterioles that are preferentially found in endosteal bone marrow. These arterioles are ensheathed exclusively by rare NG2 (also known as CSPG4)(+) pericytes, distinct from sinusoid-associated leptin receptor (LEPR)(+) cells. Pharmacological or genetic activation of the HSC cell cycle alters the distribution of HSCs from NG2(+) periarteriolar niches to LEPR(+) perisinusoidal niches. Conditional depletion of NG2(+) cells induces HSC cycling and reduces functional long-term repopulating HSCs in the bone marrow. These results thus indicate that arteriolar niches are indispensable for maintaining HSC quiescence.

  10. Local reversibility and entanglement structure of many-body ground states

    CERN Document Server

    Kuwahara, Tomotaka; Amico, Luigi; Vedral, Vlatko

    2015-01-01

    The low-temperature physics of quantum many-body systems is largely governed by the structure of their ground states. Minimizing the energy of local interactions, ground states often reflect strong properties of locality such as the area law for entanglement entropy and the exponential decay of correlations between spatially separated observables. In this letter we present a novel characterization of locality in quantum states, which we call `local reversibility'. It characterizes the type of operations that are needed to reverse the action of a general disturbance on the state. We prove that unique ground states of gapped local Hamiltonian are locally reversible. This way, we identify new fundamental features of many-body ground states, which cannot be derived from the aforementioned properties. We use local reversibility to distinguish between states enjoying microscopic and macroscopic quantum phenomena. To demonstrate the potential of our approach, we prove specific properties of ground states, which are ...

  11. Do Quiescence and Wasp Venom-Induced Lethargy Share Common Neuronal Mechanisms in Cockroaches?

    Science.gov (United States)

    Emanuel, Stav; Libersat, Frederic

    2017-01-01

    The escape behavior of a cockroach may not occur when it is either in a quiescent state or after being stung by the jewel wasp (Ampulex compressa). In the present paper, we show that quiescence is an innate lethargic state during which the cockroach is less responsive to external stimuli. The neuronal mechanism of such a state is poorly understood. In contrast to quiescence, the venom-induced lethargic state is not an innate state in cockroaches. The Jewel Wasp disables the escape behavior of cockroaches by injecting its venom directly in the head ganglia, inside a neuropile called the central complex a 'higher center' known to regulate motor behaviors. In this paper we show that the coxal slow motoneuron ongoing activity, known to be involved in posture, is reduced in quiescent animals, as compared to awake animals, and it is further reduced in stung animals. Moreover, the regular tonic firing of the slow motoneuron present in both awake and quiescent cockroaches is lost in stung cockroaches. Injection of procaine to prevent neuronal activity into the central complex to mimic the wasp venom injection produces a similar effect on the activity of the slow motoneuron. In conclusion, we speculate that the neuronal modulation during the quiescence and venom-induced lethargic states may occur in the central complex and that both states could share a common neuronal mechanism.

  12. The X-ray Spectral Evolution of Galactic Black Hole X-ray Binaries Toward Quiescence

    CERN Document Server

    Plotkin, Richard M; Jonker, Peter G

    2013-01-01

    Most transient black hole X-ray binaries (BHXBs) spend the bulk of their time in a quiescent state, where they accrete matter from their companion star at highly sub-Eddington luminosities (we define quiescence here as a normalized Eddington ratio l_x = L_{0.5-10 keV}}/L_{Edd} < 1e-5). Here, we present Chandra X-ray imaging spectroscopy for three BHXB systems (H 1743-322, MAXI J1659-152, and XTE J1752-223) as they fade into quiescence following an outburst. Multiple X-ray observations were taken within one month of each other, allowing us to track each individual system's X-ray spectral evolution during its decay. We compare these three systems to other BHXB systems. We confirm that quiescent BHXBs have softer X-ray spectra than low-hard state BHXBs, and that quiescent BHXB spectral properties show no dependence on the binary system's orbital parameters. However, the observed anti-correlation between X-ray photon index and l_x in the low-hard state does not continue once a BHXB enters quiescence. Instead, ...

  13. Reverse brain drain in South Korea: state-led model.

    Science.gov (United States)

    Yoon, B L

    1992-01-01

    Korea's reverse brain drain (RBD) has been an organized government effort, rather than a spontaneous social phenomenon, in that various policies and the political support of President Park, Chung-Hee were instrumental in laying the groundwork for its success. Particular features of Korea's RBD policies are the creation of a conducive domestic environment (i.e., government-sponsored strategic R & D institution-building, legal, and administrative reforms), and importantly, the empowerment of returnees (via, i.e., exceptionally good maternal benefits, guarantees of research autonomy). President Park played the cardinal role in empowering repatriates at the expense of his own civil bureaucracy, and his capacity for such patronage derived from Korea's bureaucratic-authoritarian political system. Returning scientists and engineers directly benefitted from this political system as well as Park's personal guardianship. For Park, empowerment of returning "brains" was necessary to accomplish his national industrialization plan, thereby enhancing his political legitimacy in domestic politics. An alliance with the R & D cadre was functionally necessary to successfully consolidate strong presidential power, and politically nonthreatening due to the particular form of "pact of domination" in Korea's power structure. RBD in Korea will continue in the near future given Korea's drive for high technology, and the remarkable expansion of local industrial and educational sectors. Korea's future RBD, however, needs to pay closer attention to the following 4 problems: research autonomy; equality issues; skill-based repatriation of technicians and engineers rather than Ph.Ds; and subsidies to small and medium industry for RBD.

  14. Msa1 and Msa2 Modulate G1-Specific Transcription to Promote G1 Arrest and the Transition to Quiescence in Budding Yeast.

    Directory of Open Access Journals (Sweden)

    Shawna Miles

    2016-06-01

    Full Text Available Yeast that naturally exhaust their glucose source can enter a quiescent state that is characterized by reduced cell size, and high cell density, stress tolerance and longevity. The transition to quiescence involves highly asymmetric cell divisions, dramatic reprogramming of transcription and global changes in chromatin structure and chromosome topology. Cells enter quiescence from G1 and we find that there is a positive correlation between the length of G1 and the yield of quiescent cells. The Swi4 and Swi6 transcription factors, which form the SBF transcription complex and promote the G1 to S transition in cycling cells, are also critical for the transition to quiescence. Swi6 forms a second complex with Mbp1 (MBF, which is not required for quiescence. These are the functional analogues of the E2F complexes of higher eukaryotes. Loss of the RB analogue, Whi5, and the related protein Srl3/Whi7, delays G1 arrest, but it also delays recovery from quiescence. Two MBF- and SBF-Associated proteins have been identified that have little effect on SBF or MBF activity in cycling cells. We show that these two related proteins, Msa1 and Msa2, are specifically required for the transition to quiescence. Like the E2F complexes that are quiescence-specific, Msa1 and Msa2 are required to repress the transcription of many SBF target genes, including SWI4, the CLN2 cyclin and histones, specifically after glucose is exhausted from the media. They also activate transcription of many MBF target genes. msa1msa2 cells fail to G1 arrest and rapidly lose viability upon glucose exhaustion. msa1msa2 mutants that survive this transition are very large, but they attain the same thermo-tolerance and longevity of wild type quiescent cells. This indicates that Msa1 and Msa2 are required for successful transition to quiescence, but not for the maintenance of that state.

  15. Planar Homotropenylium Cation : A Transition State with Reversed Aromaticity

    NARCIS (Netherlands)

    Gibson, Christopher M.; Havenith, Remco W. A.; Fowler, Patrick W.; Jenneskens, Leonardus W.

    2015-01-01

    In contrast to the equilibrium structure of the homoaromatic C-s homotropenylium cation, C8H9+ (1), which supports a pinched diatropic ring current, the C(2)v transition state (2) for inversion of the methylene bridge of 1 is antiaromatic and supports a two-lobe paratropic pi current, as detected by

  16. Reversal of Flux Closure States in Cobalt Nanoparticle Rings With Coaxial Magnetic Pulses

    DEFF Research Database (Denmark)

    Kasama, T; Dunin-Borkowski, Rafal E.; Scheinfein, MR

    2008-01-01

    Bistable flux closure (FC) states in Co nanoparticle rings can be switched reversibly by applying a coaxial magnetic field (H-z). The FC switching phenomena can be reproduced by micromagnetics simulations, which also reveal novel magnetic states at intermediate applied field strengths....

  17. A Radio-loud Magnetar in X-ray Quiescence

    CERN Document Server

    Levin, Lina; Bates, Samuel; Bhat, N D Ramesh; Burgay, Marta; Burke-Spolaor, Sarah; D'Amico, Nichi; Johnston, Simon; Keith, Michael; Kramer, Michael; Milia, Sabrina; Possenti, Andrea; Rea, Nanda; Stappers, Ben; van Straten, Willem

    2010-01-01

    As part of a survey for radio pulsars with the Parkes 64-m telescope we have discovered PSR J1622-4950, a pulsar with a 4.3-s rotation period. Follow-up observations show that the pulsar has the highest inferred surface magnetic field of the known radio pulsars (B ~ 3e14 G), exhibits significant timing noise and appears to have an inverted spectrum. Unlike the vast majority of the known pulsar population, PSR J1622-4950 appears to switch off for many hundreds of days and even in its on-state exhibits extreme variability in its flux density. Furthermore, the integrated pulse profile changes shape with epoch. All of these properties are remarkably similar to the only two magnetars previously known to emit radio pulsations. The position of PSR J1622-4950 is coincident with an X-ray source that, unlike the other radio pulsating magnetars, was found to be in quiescence. We conclude that our newly discovered pulsar is a magnetar - the first to be discovered via its radio emission.

  18. Uropathogenic Escherichia coli Metabolite-Dependent Quiescence and Persistence May Explain Antibiotic Tolerance during Urinary Tract Infection.

    Science.gov (United States)

    Leatham-Jensen, Mary P; Mokszycki, Matthew E; Rowley, David C; Deering, Robert; Camberg, Jodi L; Sokurenko, Evgeni V; Tchesnokova, Veronika L; Frimodt-Møller, Jakob; Krogfelt, Karen A; Leth Nielsen, Karen; Frimodt-Møller, Niels; Sun, Gongqin; Cohen, Paul S

    2016-01-01

    In the present study, it is shown that although Escherichia coli CFT073, a human uropathogenic (UPEC) strain, grows in liquid glucose M9 minimal medium, it fails to grow on glucose M9 minimal medium agar plates seeded with ≤10(6) CFU. The cells on glucose plates appear to be in a "quiescent" state that can be prevented by various combinations of lysine, methionine, and tyrosine. Moreover, the quiescent state is characteristic of ~80% of E. coli phylogenetic group B2 multilocus sequence type 73 strains, as well as 22.5% of randomly selected UPEC strains isolated from community-acquired urinary tract infections in Denmark. In addition, E. coli CFT073 quiescence is not limited to glucose but occurs on agar plates containing a number of other sugars and acetate as sole carbon sources. It is also shown that a number of E. coli CFT073 mini-Tn5 metabolic mutants (gnd, gdhA, pykF, sdhA, and zwf) are nonquiescent on glucose M9 minimal agar plates and that quiescence requires a complete oxidative tricarboxylic acid (TCA) cycle. In addition, evidence is presented that, although E. coli CFT073 quiescence and persistence in the presence of ampicillin are alike in that both require a complete oxidative TCA cycle and each can be prevented by amino acids, E. coli CFT073 quiescence occurs in the presence or absence of a functional rpoS gene, whereas maximal persistence requires a nonfunctional rpoS. Our results suggest that interventions targeting specific central metabolic pathways may mitigate UPEC infections by interfering with quiescence and persistence. IMPORTANCE Recurrent urinary tract infections (UTIs) affect 10 to 40% of women. In up to 77% of those cases, the recurrent infections are caused by the same uropathogenic E. coli (UPEC) strain that caused the initial infection. Upon infection of urothelial transitional cells in the bladder, UPEC appear to enter a nongrowing quiescent intracellular state that is thought to serve as a reservoir responsible for recurrent

  19. Uropathogenic Escherichia coli Metabolite-Dependent Quiescence and Persistence May Explain Antibiotic Tolerance during Urinary Tract Infection

    Science.gov (United States)

    Leatham-Jensen, Mary P.; Mokszycki, Matthew E.; Rowley, David C.; Deering, Robert; Camberg, Jodi L.; Sokurenko, Evgeni V.; Tchesnokova, Veronika L.; Frimodt-Møller, Jakob; Leth Nielsen, Karen; Sun, Gongqin

    2016-01-01

    ABSTRACT In the present study, it is shown that although Escherichia coli CFT073, a human uropathogenic (UPEC) strain, grows in liquid glucose M9 minimal medium, it fails to grow on glucose M9 minimal medium agar plates seeded with ≤106 CFU. The cells on glucose plates appear to be in a “quiescent” state that can be prevented by various combinations of lysine, methionine, and tyrosine. Moreover, the quiescent state is characteristic of ~80% of E. coli phylogenetic group B2 multilocus sequence type 73 strains, as well as 22.5% of randomly selected UPEC strains isolated from community-acquired urinary tract infections in Denmark. In addition, E. coli CFT073 quiescence is not limited to glucose but occurs on agar plates containing a number of other sugars and acetate as sole carbon sources. It is also shown that a number of E. coli CFT073 mini-Tn5 metabolic mutants (gnd, gdhA, pykF, sdhA, and zwf) are nonquiescent on glucose M9 minimal agar plates and that quiescence requires a complete oxidative tricarboxylic acid (TCA) cycle. In addition, evidence is presented that, although E. coli CFT073 quiescence and persistence in the presence of ampicillin are alike in that both require a complete oxidative TCA cycle and each can be prevented by amino acids, E. coli CFT073 quiescence occurs in the presence or absence of a functional rpoS gene, whereas maximal persistence requires a nonfunctional rpoS. Our results suggest that interventions targeting specific central metabolic pathways may mitigate UPEC infections by interfering with quiescence and persistence. IMPORTANCE Recurrent urinary tract infections (UTIs) affect 10 to 40% of women. In up to 77% of those cases, the recurrent infections are caused by the same uropathogenic E. coli (UPEC) strain that caused the initial infection. Upon infection of urothelial transitional cells in the bladder, UPEC appear to enter a nongrowing quiescent intracellular state that is thought to serve as a reservoir responsible

  20. Identified Serotonin-Releasing Neurons Induce Behavioral Quiescence and Suppress Mating in Drosophila.

    Science.gov (United States)

    Pooryasin, Atefeh; Fiala, André

    2015-09-16

    Animals show different levels of activity that are reflected in sensory responsiveness and endogenously generated behaviors. Biogenic amines have been determined to be causal factors for these states of arousal. It is well established that, in Drosophila, dopamine and octopamine promote increased arousal. However, little is known about factors that regulate arousal negatively and induce states of quiescence. Moreover, it remains unclear whether global, diffuse modulatory systems comprehensively affecting brain activity determine general states of arousal. Alternatively, individual aminergic neurons might selectively modulate the animals' activity in a distinct behavioral context. Here, we show that artificially activating large populations of serotonin-releasing neurons induces behavioral quiescence and inhibits feeding and mating. We systematically narrowed down a role of serotonin in inhibiting endogenously generated locomotor activity to neurons located in the posterior medial protocerebrum. We identified neurons of this cell cluster that suppress mating, but not feeding behavior. These results suggest that serotonin does not uniformly act as global, negative modulator of general arousal. Rather, distinct serotoninergic neurons can act as inhibitory modulators of specific behaviors. An animal's responsiveness to external stimuli and its various types of endogenously generated, motivated behavior are highly dynamic and change between states of high activity and states of low activity. It remains unclear whether these states are mediated by unitary modulatory systems globally affecting brain activity, or whether distinct neurons modulate specific neuronal circuits underlying particular types of behavior. Using the model organism Drosophila melanogaster, we find that activating large proportions of serotonin-releasing neurons induces behavioral quiescence. Moreover, distinct serotonin-releasing neurons that we genetically isolated and identified negatively affect

  1. Magnetization reversal assisted by half antivortex states in nanostructured circular cobalt disks

    Energy Technology Data Exchange (ETDEWEB)

    Lara, A.; Aliev, F. G., E-mail: farkhad.aliev@uam.es [Dpto. Física de la Materia Condensada, Instituto Nicolas Cabrera (INC) and Condensed Matter Physics Institute (IFIMAC), Universidad Autónoma de Madrid, Madrid (Spain); Dobrovolskiy, O. V. [Physikalisches Institut, Goethe University, Frankfurt am Main (Germany); Physics Department, V. Karazin National University, Kharkiv (Ukraine); Prieto, J. L. [Instituto de Sistemas Optoelectrónicos y Microtecnología (ISOM), Universidad Politecnica de Madrid (Spain); Huth, M. [Physikalisches Institut, Goethe University, Frankfurt am Main (Germany)

    2014-11-03

    The half antivortex, a fundamental topological structure which determines magnetization reversal of submicron magnetic devices with domain walls, has been suggested also to play a crucial role in spin torque induced vortex core reversal in circular disks. Here, we report on magnetization reversal in circular disks with nanoholes through consecutive metastable states with half antivortices. In-plane anisotropic magnetoresistance and broadband susceptibility measurements accompanied by micromagnetic simulations reveal that cobalt (Co) disks with two and three linearly arranged nanoholes directed at 45° and 135° with respect to the external magnetic field show reproducible step-like changes in the anisotropic magnetoresistance and magnetic permeability due to transitions between different intermediate states mediated by vortices and half antivortices confined to the dot nanoholes and edges, respectively. Our findings are relevant for the development of multi-hole based spintronic and magnetic memory devices.

  2. Methylene blue promotes quiescence of rat neural progenitor cells.

    Science.gov (United States)

    Xie, Luokun; Choudhury, Gourav R; Wang, Jixian; Park, Yong; Liu, Ran; Yuan, Fang; Zhang, Chun-Li; Yorio, Thomas; Jin, Kunlin; Yang, Shao-Hua

    2014-01-01

    Neural stem cell-based treatment holds a new therapeutic opportunity for neurodegenerative disorders. Here, we investigated the effect of methylene blue on proliferation and differentiation of rat neural progenitor cells (NPCs) both in vitro and in vivo. We found that methylene blue inhibited proliferation and promoted quiescence of NPCs in vitro without affecting committed neuronal differentiation. Consistently, intracerebroventricular infusion of methylene blue significantly inhibited NPC proliferation at the subventricular zone (SVZ). Methylene blue inhibited mTOR signaling along with down-regulation of cyclins in NPCs in vitro and in vivo. In summary, our study indicates that methylene blue may delay NPC senescence through enhancing NPCs quiescence.

  3. Highly Potent Extracts from Pea (Pisum sativum) and Maize (Zea mays) Roots Can Be Used to Induce Quiescence in Entomopathogenic Nematodes.

    Science.gov (United States)

    Jaffuel, Geoffrey; Hiltpold, Ivan; Turlings, Ted C J

    2015-09-01

    Root exudates can play an important role in plant-nematode interactions. Recent studies have shown that the root cap exudates obtained from several plant species trigger a state of dormancy or quiescence in various genera of nematodes. This phenomenon is not only of fundamental ecological interest, but also has application potential if the plant-produced compound(s) could be used to control harmful nematodes or help to prolong the shelf-life of beneficial entomopathogenic nematodes (EPNs). The identification of the compound(s) involved in quiescence induction has proven to be a major challenge and requires large amounts of active material. Here, we present a high-throughput method to obtain bioactive root extracts from flash-frozen root caps of green pea and maize. The root cap extract obtained via this method was considerably more potent in inducing quiescence than exudate obtained by a previously used method, and consistently induced quiescence in the EPN Heterorhabditis megidis, even after a 30-fold dilution. Extracts obtained from the rest of the root were equally effective in inducing quiescence. Infective juveniles (IJs) of H. megidis exposed to these extracts readily recovered from their quiescent state as soon as they were placed in moist soil, and they were at least as infectious as the IJs that had been stored in water. Excessive exposure of IJs to air interfered with the triggering of quiescence. The implications of these results and the next steps towards identification of the quiescence-inducing compound(s) are discussed from the perspective of applying EPN against soil-dwelling insect pests.

  4. The Black Hole Binary V4641 Sagitarii: Activity in Quiescence & Improved Mass Determinations

    CERN Document Server

    MacDonald, Rachel K D; Buxton, Michelle; Cantrell, Andrew G; Chatterjee, Ritaban; Kennedy-Shaffer, Ross; Orosz, Jerome A; Markwardt, Craig B; Swank, Jean H

    2014-01-01

    We examine ~10 years of photometric data and find that the black hole X-ray binary V4641 Sgr has two optical states, passive and active, during X-ray quiescence. The passive state is dominated by ellipsoidal variations and is stable in the shape and variability of the light curve. The active state is brighter and more variable. Emission during the active state varies over the course of the orbital period and is redder than the companion star. These optical/infrared states last for weeks or months. V4641 Sgr spends approximately 85% of X-ray quiescence in the passive state and 15% in the active. We analyze passive colors and spectroscopy of V4641 Sgr and show that they are consistent with a reddened B9III star (with E(B-V) = 0.37 +/- 0.19) with little or no contribution from the accretion disk. We use X-ray observations with an updated ephemeris to place an upper limit on the duration of an X-ray eclipse of <8.3 deg in phase (~1.6 hours). High resolution spectroscopy yields a greatly improved measurement of...

  5. Situational State Balances and Participation Motivation in Youth Sport: A Reversal Theory Perspective

    Science.gov (United States)

    Sit, Cindy H. P.; Lindner, Koenraad J.

    2006-01-01

    Background: Reversal theory (Apter, 1982, 1989, ) is one of the motivational frameworks which attempts to examine human subjective experiences and behaviours. There are four dyads of metamotivational states (telic-paratelic, conformist-negativistic, autic-alloic, and mastery-sympathy) and individuals may prefer to be in one rather than the other…

  6. Simulations of a quasi-Taylor state geomagnetic field including polarity reversals on the Earth Simulator.

    Science.gov (United States)

    Takahashi, Futoshi; Matsushima, Masaki; Honkura, Yoshimori

    2005-07-15

    High-resolution, low-viscosity geodynamo simulations have been carried out on the Earth Simulator, one of the fastest supercomputers, in a dynamic regime similar to that of Earth's core, that is, in a quasi-Taylor state. Our dynamo models exhibit features of the geodynamo not only in spatial and temporal characteristics but also in dynamics. Polarity reversals occurred when magnetic flux patches at high latitudes moved poleward and disappeared; patches with reversed field at low and mid-latitudes then moved poleward.

  7. Polar Kerr effect studies of time reversal symmetry breaking states in heavy fermion superconductors

    Science.gov (United States)

    Schemm, E. R.; Levenson-Falk, E. M.; Kapitulnik, A.

    2017-04-01

    The connection between chiral superconductivity and topological order has emerged as an active direction in research as more instances of both have been identified in condensed matter systems. With the notable exception of 3He-B, all of the known or suspected chiral - that is to say time-reversal symmetry-breaking (TRSB) - superfluids arise in heavy fermion superconductors, although the vast majority of heavy fermion superconductors preserve time-reversal symmetry. Here we review recent experimental efforts to identify TRSB states in heavy fermion systems via measurement of polar Kerr effect, which is a direct consequence of TRSB.

  8. Experimental Test of the State Estimation-Reversal Tradeoff Relation in General Quantum Measurements

    Directory of Open Access Journals (Sweden)

    Geng Chen

    2014-06-01

    Full Text Available When a measurement has limited strength, only partial information, regarding the initial state, is extracted, and, correspondingly, there is a probability to reverse its effect on the system and retrieve the original state. Recently, a clear and direct quantitative description of this complementary relationship, in terms of a tradeoff relation, was developed by Y. K. Cheong and S. W. Lee. [Phys. Rev. Lett. 109, 150402 (2012]. Here, this tradeoff relation is experimentally verified using polarization-encoded single photons from a quantum dot. Measurement operators representing a complete range, from not affecting the system to a projection to a single polarization state, are realized. In addition, for each measurement operator, an optimal reversal operator is also implemented. The upper bound of the tradeoff relation is mapped to experimental parameters representing the measurement strength. Our results complement the theoretical work and provide a hands-on characterization of general quantum measurements.

  9. Quantitative Mapping of Precursory Seismic Quiescence Before Large Aftershocks

    Science.gov (United States)

    Neukomm, S.; Wiemer, S.; Giardini, D.

    2002-12-01

    A relative decrease of aftershock activity before the occurrence of large aftershocks to M6+ mainshocks is one of only few earthquake precursors accepted for the IASPEI preliminary list of significant earthquake precursors. If one considers earthquake rate to be dependent on stressing rate, aftershocks sequences offer in fact an ideal environment to detect precursory quiescence before large earthquakes: The numerous aftershocks allow a much higher spatial and temporal resolution of transients in seismicity than possible with the average background rate of micro-earthquakes. Past studies of precursory quiescence before larger aftershocks, however, have largely been based on bulk value. The aim of this study is to map the temporal and spatial variability of activity rate within several rich aftershock sequences, and, possibly, exploit the results for improving real time probabilistic aftershock hazard assessment. We introduce a new algorithm based on fitting the modified Omori law to the aftershock sequences. At arbitrarily chosen grid points, the Omori parameters of the sub-samples containing all aftershock within 5 or 10 km of the node are estimated at time t. We calculate the number of aftershocks N +/- dN in the time interval t + dt using the relevant four Omori parameters (p, c and k) parameters and their corresponding standard deviations estimated using a bootstrap analysis. The difference between the forecasted and the observed number of aftershocks, normalized by the standard deviation of the forecast, is our estimator of rate change. The algorithm is tested on synthetic aftershock sequences containing artificial quiescences in order to calibrate the free parameters for optimal detection of precursory quiescence. We then perform our spatial and temporal mapping for several prominent Californian and Japanese aftershock sequences (Landers, Hector Mine, Northridge, Loma Prieta, Kobe, Western Tottori and Hokkaido). Preliminary results suggest that we cannot

  10. Protein S Regulates Neural Stem Cell Quiescence and Neurogenesis.

    Science.gov (United States)

    Zelentsova, Katya; Talmi, Ziv; Abboud-Jarrous, Ghada; Sapir, Tamar; Capucha, Tal; Nassar, Maria; Burstyn-Cohen, Tal

    2017-03-01

    Neurons are continuously produced in brains of adult mammalian organisms throughout life-a process tightly regulated to ensure a balanced homeostasis. In the adult brain, quiescent Neural Stem Cells (NSCs) residing in distinct niches engage in proliferation, to self-renew and to give rise to differentiated neurons and astrocytes. The mechanisms governing the intricate regulation of NSC quiescence and neuronal differentiation are not completely understood. Here, we report the expression of Protein S (PROS1) in adult NSCs, and show that genetic ablation of Pros1 in neural progenitors increased hippocampal NSC proliferation by 47%. We show that PROS1 regulates the balance of NSC quiescence and proliferation, also affecting daughter cell fate. We identified the PROS1-dependent downregulation of Notch1 signaling to correlate with NSC exit from quiescence. Notch1 and Hes5 mRNA levels were rescued by reintroducing Pros1 into NCS or by supplementation with purified PROS1, suggesting the regulation of Notch pathway by PROS1. Although Pros1-ablated NSCs show multilineage differentiation, we observed a 36% decrease in neurogenesis, coupled with a similar increase in astrogenesis, suggesting PROS1 is instructive for neurogenesis, and plays a role in fate determination, also seen in aged mice. Rescue experiments indicate PROS1 is secreted by NSCs and functions by a NSC-endogenous mechanism. Our study identifies a duple role for PROS1 in stem-cell quiescence and as a pro-neurogenic factor, and highlights a unique segregation of increased stem cell proliferation from enhanced neuronal differentiation, providing important insight into the regulation and control of NSC quiescence and differentiation. Stem Cells 2017;35:679-693.

  11. Quiescence of human muscle stem cells is favored by culture on natural biopolymeric films.

    Science.gov (United States)

    Monge, Claire; DiStasio, Nicholas; Rossi, Thomas; Sébastien, Muriel; Sakai, Hiroshi; Kalman, Benoit; Boudou, Thomas; Tajbakhsh, Shahragim; Marty, Isabelle; Bigot, Anne; Mouly, Vincent; Picart, Catherine

    2017-05-02

    Satellite cells are quiescent resident muscle stem cells that present an important potential to regenerate damaged tissue. However, this potential is diminished once they are removed from their niche environment in vivo, prohibiting the long-term study and genetic investigation of these cells. This study therefore aimed to provide a novel biomaterial platform for the in-vitro culture of human satellite cells that maintains their stem-like quiescent state, an important step for cell therapeutic studies. Human muscle satellite cells were isolated from two donors and cultured on soft biopolymeric films of controlled stiffness. Cell adhesive phenotype, maintenance of satellite cell quiescence and capacity for gene manipulation were investigated using FACS, western blotting, fluorescence microscopy and electron microscopy. About 85% of satellite cells cultured in vitro on soft biopolymer films for 3 days maintained expression of the quiescence marker Pax7, as compared with 60% on stiffer films and 50% on tissue culture plastic. The soft biopolymeric films allowed satellite cell culture for up to 6 days without renewing the media. These cells retained their stem-like properties, as evidenced by the expression of stem cell markers and reduced expression of differentiated markers. In addition, 95% of cells grown on these soft biopolymeric films were in the G0/G1 stage of the cell cycle, as opposed to those grown on plastic that became activated and began to proliferate and differentiate. Our study identifies a new biomaterial made of a biopolymer thin film for the maintenance of the quiescence state of muscle satellite cells. These cells could be activated at any point simply by replating them onto a plastic culture dish. Furthermore, these cells could be genetically manipulated by viral transduction, showing that this biomaterial may be further used for therapeutic strategies.

  12. Sumoylation is tumor-suppressive and confers proliferative quiescence to hematopoietic progenitors in Drosophila melanogaster larvae

    Directory of Open Access Journals (Sweden)

    Marta E. Kalamarz

    2011-12-01

    How cell-intrinsic regulation of the cell cycle and the extrinsic influence of the niche converge to provide proliferative quiescence, safeguard tissue integrity, and provide avenues to stop stem cells from giving rise to tumors is a major challenge in gene therapy and tissue engineering. We explore this question in sumoylation-deficient mutants of Drosophila. In wild type third instar larval lymph glands, a group of hematopoietic stem/progenitor cells acquires quiescence; a multicellular niche supports their undifferentiated state. However, how proliferative quiescence is instilled in this population is not understood. We show that Ubc9 protein is nuclear in this population. Loss of the SUMO-activating E1 enzyme, Aos1/Uba2, the conjugating E2 enzyme, Ubc9, or the E3 SUMO ligase, PIAS, results in a failure of progenitors to quiesce; progenitors become hyperplastic, misdifferentiate, and develop into microtumors that eventually detach from the dorsal vessel. Significantly, dysplasia and lethality of Ubc9 mutants are rescued when Ubc9wt is provided specifically in the progenitor populations, but not when it is provided in the niche or in the differentiated cortex. While normal progenitors express high levels of the Drosophila cyclin-dependent kinase inhibitor p21 homolog, Dacapo, the corresponding overgrown mutant population exhibits a marked reduction in Dacapo. Forced expression of either Dacapo or human p21 in progenitors shrinks this population. The selective expression of either protein in mutant progenitor cells, but not in other hematopoietic populations, limits overgrowth, blocks tumorogenesis, and restores organ integrity. We discuss an essential and complex role for sumoylation in preserving the hematopoietic progenitor states for stress response and in the context of normal development of the fly.

  13. Pairing state with a time-reversal symmetry breaking in FeAs-based superconductors.

    Science.gov (United States)

    Lee, Wei-Cheng; Zhang, Shou-Cheng; Wu, Congjun

    2009-05-29

    We investigate the competition between the extended s+/--wave and dx2-y2-wave pairing order parameters in the iron-based superconductors. Because of the frustrating pairing interactions among the electron and the hole Fermi pockets, a time-reversal symmetry breaking s+id pairing state could be favored. We analyze this pairing state within the Ginzburg-Landau theory and explore the experimental consequences. In such a state, spatial inhomogeneity induces a supercurrent near a nonmagnetic impurity and the corners of a square sample. The resonance mode between the s+/-- and dx2-y2-wave order parameters can be detected through the B1g Raman spectroscopy.

  14. The reversibility of sea ice loss in a state-of-the-art climate model

    OpenAIRE

    Armour, K. C.; Eisenman, I; Blanchard-Wrigglesworth, E.; McCusker, K. E.; Bitz, C.M.

    2011-01-01

    Rapid Arctic sea ice retreat has fueled speculation about the possibility of threshold (or ‘tipping point’) behavior and irreversible loss of the sea ice cover. We test sea ice reversibility within a state-of-the-art atmosphere–ocean global climate model by increasing atmospheric carbon dioxide until the Arctic Ocean becomes ice-free throughout the year and subsequently decreasing it until the initial ice cover returns. Evidence for irreversibility in the form of hysteresis outside the envelo...

  15. Reversible photo-chem-electrotriggered three-state luminescence switching based on core-shell nanostructures

    Science.gov (United States)

    Zhai, Yanling; Zhu, Zhijun; Zhu, Chengzhou; Zhu, Jinbo; Ren, Jiangtao; Wang, Erkang; Dong, Shaojun

    2013-05-01

    Reversible three-state fluorescence switches triggered by light, electricity and chemical inputs based on ``sponges'' of Pyronin Y-doped silica nanoparticles (PYDS) and polyoxometalate K14[Na(H2O)P5W30O110] (Na-POMs) core-shell nanostructures were realized. Under one or two signal inputs, the system exhibited distinct three-state interconvertible automaton, achieving reversible ``on'' and ``off'' luminescence switches via the related luminescence quenching effect. The features of the system correspond to the equivalent circuitry of an IMPLICATION logic gate performing the Boolean operation by using potential and chemical as inputs. Such a multi-chromic device with novel structure possesses several advantages, such as relative low operation voltage, large reproducibility and reversibility, apparent fluorescence contrast, and long-time stability, which make it a suitable candidate for nonvolatile memory devices. In addition, the current protocol for the hybrid film fabrication can be easily extended from the polyoxometalate and organic dyes to other novel nanostructures matched multifunctional stimulus-responsive species and fluorescence materials in the future.Reversible three-state fluorescence switches triggered by light, electricity and chemical inputs based on ``sponges'' of Pyronin Y-doped silica nanoparticles (PYDS) and polyoxometalate K14[Na(H2O)P5W30O110] (Na-POMs) core-shell nanostructures were realized. Under one or two signal inputs, the system exhibited distinct three-state interconvertible automaton, achieving reversible ``on'' and ``off'' luminescence switches via the related luminescence quenching effect. The features of the system correspond to the equivalent circuitry of an IMPLICATION logic gate performing the Boolean operation by using potential and chemical as inputs. Such a multi-chromic device with novel structure possesses several advantages, such as relative low operation voltage, large reproducibility and reversibility, apparent fluorescence

  16. Polar Kerr effect studies of time reversal symmetry breaking states in heavy fermion superconductors

    Energy Technology Data Exchange (ETDEWEB)

    Schemm, E.R., E-mail: eschemm@alumni.stanford.edu [Geballe Laboratory for Advanced Materials, Stanford University, Stanford, CA 94305 (United States); Levenson-Falk, E.M. [Geballe Laboratory for Advanced Materials, Stanford University, Stanford, CA 94305 (United States); Department of Physics, Stanford University, Stanford, CA 94305 (United States); Kapitulnik, A. [Geballe Laboratory for Advanced Materials, Stanford University, Stanford, CA 94305 (United States); Department of Physics, Stanford University, Stanford, CA 94305 (United States); Department of Applied Physics, Stanford University, Stanford, CA 94305 (United States); Stanford Institute of Energy and Materials Science, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA 94025 (United States)

    2017-04-15

    Highlights: • Polar Kerr effect (PKE) probes broken time-reversal symmetry (TRS) in superconductors. • Absence of PKE below Tc in CeCoIn{sub 5} is consistent with dx2-y2 order parameter symmetry. • PKE in the B phase of the multiphase superconductor UPt3 agrees with an E2u model. • Data on URu2Si2 show broken TRS and additional structure in the superconducting state. - Abstract: The connection between chiral superconductivity and topological order has emerged as an active direction in research as more instances of both have been identified in condensed matter systems. With the notable exception of {sup 3}He-B, all of the known or suspected chiral – that is to say time-reversal symmetry-breaking (TRSB) – superfluids arise in heavy fermion superconductors, although the vast majority of heavy fermion superconductors preserve time-reversal symmetry. Here we review recent experimental efforts to identify TRSB states in heavy fermion systems via measurement of polar Kerr effect, which is a direct consequence of TRSB.

  17. Uropathogenic Escherichia coli metabolite-dependent quiescence and persistence may explain antibiotic tolerance during urinary tract infection

    DEFF Research Database (Denmark)

    Leatham-Jensen, Mary P.; Mokszycki, Matthew E.; Rowley, David C.

    2016-01-01

    infections by interfering with quiescence and persistence. IMPORTANCE Recurrent urinary tract infections (UTIs) affect 10 to 40% of women. In up to 77% of those cases, the recurrent infections are caused by the same uropathogenic E. coli (UPEC) strain that caused the initial infection. Upon infection...... that can be prevented by various combinations of lysine, methionine, and tyrosine. Moreover, the quiescent state is characteristic of ~80% of E. coli phylogenetic group B2 multilocus sequence type 73 strains, as well as 22.5% of randomly selected UPEC strains isolated from community-acquired urinary tract...... infections in Denmark. In addition, E. coli CFT073 quiescence is not limited to glucose but occurs on agar plates containing a number of other sugars and acetate as sole carbon sources. It is also shown that a number of E. coli CFT073 mini-Tn5 metabolic mutants (gnd, gdhA, pykF, sdhA, and zwf...

  18. Uropathogenic Escherichia coli metabolite-dependent quiescence and persistence may explain antibiotic tolerance during urinary tract infection

    DEFF Research Database (Denmark)

    Leatham-Jensen, Mary P.; Mokszycki, Matthew E.; Rowley, David C.

    2016-01-01

    infections by interfering with quiescence and persistence. IMPORTANCE Recurrent urinary tract infections (UTIs) affect 10 to 40% of women. In up to 77% of those cases, the recurrent infections are caused by the same uropathogenic E. coli (UPEC) strain that caused the initial infection. Upon infection...... that can be prevented by various combinations of lysine, methionine, and tyrosine. Moreover, the quiescent state is characteristic of ~80% of E. coli phylogenetic group B2 multilocus sequence type 73 strains, as well as 22.5% of randomly selected UPEC strains isolated from community-acquired urinary tract...... infections in Denmark. In addition, E. coli CFT073 quiescence is not limited to glucose but occurs on agar plates containing a number of other sugars and acetate as sole carbon sources. It is also shown that a number of E. coli CFT073 mini-Tn5 metabolic mutants (gnd, gdhA, pykF, sdhA, and zwf...

  19. Observations of IGR J00291+5934 in quiescence

    CERN Document Server

    Jonker, P G; Steeghs, D

    2008-01-01

    We report on optical and X-ray observations of the accretion powered ms pulsar IGR J00291+5934 in quiescence. Time resolved I-band photometry has been obtained with the 4.2 m William Herschel Telescope, while a 3 ks Chandra observation provided contemporaneous X-ray coverage. We found an unabsorbed 0.5-10 keV X-ray flux of 1x10^-13 erg cm-2 s-1 which implies that the source was in quiescence at the time of the optical observations. Nevertheless, the optical I-band light curve of IGR J00291+5934 shows evidence for strong flaring. After removal of the strongest flares, we find evidence for an orbital modulation in the phase folded I-band light curve. The overall modulation can be described by effects resulting from the presence of a superhump. Comparing our lightcurve with that reported recently we find evidence for a change in the quiescent base level. Similar changes have now been reported for 4 soft X-ray transients implying that they may be a common feature of such systems in quiescence. Furthermore, the ma...

  20. Constructing quantum dissipations and their reversible states from classical interacting spin systems

    Energy Technology Data Exchange (ETDEWEB)

    Goderis, D.; Maes, C. (Liege Univ. (BE))

    1991-01-01

    The relation between certain quantum systems and classical stochastic processes - e.g. in the method of functional integration - is formulated on the level of the dynamics for both quantum and classical dissipative time evolutions. An essentially unique quantum dissipation is constructed from a classical interacting spin system, preserving the notion of detailed balance. Translation invariant and reversible infinite volume quantum dynamics are found in this way and the Hamiltonian is recovered from the action of the generator in the GNS-representation of the corresponding groundstate for which a Feynmann-Kac formula holds. Local reversibility of quantum dissipations is shown to give rise to an almost classical characterization of the corresponding quantum states.

  1. The Black Hole Binary V4641 Sagitarii: Activity in Quiescence and Improved Mass Determinations

    Science.gov (United States)

    MacDonald, Rachel K. D.; Bailyn, Charles D.; Buxton, Michelle; Cantrell, Andrew G.; Chatterjee, Ritaban; Kennedy-Shaffer, Ross; Orosz, Jerome A.; Markwardt, Craig B.; Swank, Jean H.

    2014-03-01

    We examine ~10 yr of photometric data and find that the black hole X-ray binary V4641 Sgr has two optical states, passive and active, during X-ray quiescence. The passive state is dominated by ellipsoidal variations and is stable in the shape and variability of the light curve. The active state is brighter and more variable. Emission during the active state varies over the course of the orbital period and is redder than the companion star. These optical/infrared states last for weeks or months. V4641 Sgr spends approximately 85% of X-ray quiescence in the passive state and 15% in the active. We analyze passive colors and spectroscopy of V4641 Sgr and show that they are consistent with a reddened B9III star (with E(B - V) = 0.37 ± 0.19) with little or no contribution from the accretion disk. We use X-ray observations with an updated ephemeris to place an upper limit on the duration of an X-ray eclipse of measurement of the rotational velocity of the companion star of V rotsin i = 100.9 ± 0.8 km s-1. We fit ellipsoidal models to the passive state data and find an inclination angle of i = 72.3 ± 4.°1, a mass ratio of Q = 2.2 ± 0.2, and component masses for the system of M BH = 6.4 ± 0.6 M ⊙ and M 2 = 2.9 ± 0.4 M ⊙. Using these values we calculate an updated distance to V4641 Sgr of 6.2 ± 0.7 kpc.

  2. Regulation of the quiescence-induced genes: quiescin Q6, decorin, and ribosomal protein S29.

    Science.gov (United States)

    Coppock, D; Kopman, C; Gudas, J; Cina-Poppe, D A

    2000-03-16

    The transition from growth to quiescence is deeply deranged in cancer cells. Expression of the quiescence-induced genes, quiescin Q6, decorin, and S29, was examined in important physiological states and in several cell types. Senescent fibroblasts expressed neither Q6 nor decorin mRNAs. The quiescins were induced in serum-deprived cultures. Trypsinized cells, which rapidly reattached to the culture dish, expressed Q6, S29, and decorin mRNAs at reduced levels, compared to those that remained in suspension. Expression of Q6 and S29 mRNAs in endothelial cells was low in growth phase and high in quiescent cells. Q6 and S29 mRNAs were found in a large variety of human tissues. The quiescin Q6 protein was detected in WI38 cell extracts and in conditioned medium from quiescent cells. A complex regulation of the quiescins by growth and attachment status in specific cell types may be of importance in pathological growth regulation and the development of cancer.

  3. Phenotypic evolutionary models in stem cell biology: replacement, quiescence, and variability.

    Directory of Open Access Journals (Sweden)

    Marc Mangel

    Full Text Available Phenotypic evolutionary models have been used with great success in many areas of biology, but thus far have not been applied to the study of stem cells except for investigations of cancer. We develop a framework that allows such modeling techniques to be applied to stem cells more generally. The fundamental modeling structure is the stochastic kinetics of stem cells in their niche and of transit amplifying and fully differentiated cells elsewhere in the organism, with positive and negative feedback. This formulation allows graded signals to be turned into all or nothing responses, and shows the importance of looking beyond the niche for understanding how stem cells behave. Using the deterministic version of this framework, we show how competition between different stem cell lines can be analyzed, and under what circumstances stem cells in a niche will be replaced by other stem cells with different phenotypic characteristics. Using the stochastic version of our framework and state dependent life history theory, we show that the optimal behavior of a focal stem cell will involve long periods of quiescence and that a population of identical stem cells will show great variability in the times at which activity occurs; we compare our results with classic ones on quiescence and variability in the hematopoietic system.

  4. FOXO3 Promotes Quiescence in Adult Muscle Stem Cells during the Process of Self-Renewal

    Directory of Open Access Journals (Sweden)

    Suchitra D. Gopinath

    2014-04-01

    Full Text Available Skeletal muscle stem cells, or “satellite cells” (SCs, are required for the regeneration of damaged muscle tissue. Although SCs self-renew during regeneration, the mechanisms that govern SC re-entry into quiescence remain elusive. We show that FOXO3, a member of the forkhead family of transcription factors, is expressed in quiescent SCs (QSCs. Conditional deletion of Foxo3 in QSCs impairs self-renewal and increases the propensity of SCs to adopt a differentiated fate. Transcriptional analysis of SCs lacking FOXO3 revealed a downregulation of Notch signaling, a key regulator of SC quiescence. Conversely, overexpression of Notch intracellular domain (NICD rescued the self-renewal deficit of FOXO3-deficient SCs. We show that FOXO3 regulates NOTCH1 and NOTCH3 receptor expression and that decreasing expression of NOTCH1 and NOTCH3 receptors phenocopies the effect of FOXO3 deficiency in SCs. We demonstrate that FOXO3, perhaps by activating Notch signaling, promotes the quiescent state during SC self-renewal in adult muscle regeneration.

  5. Stress tolerance during diapause and quiescence of the brine shrimp, Artemia.

    Science.gov (United States)

    MacRae, Thomas H

    2016-01-01

    Oviparously developing embryos of the brine shrimp, Artemia, arrest at gastrulation and are released from females as cysts before entering diapause, a state of dormancy and stress tolerance. Diapause is terminated by an external signal, and growth resumes if conditions are permissible. However, if circumstances are unfavorable, cysts enter quiescence, a dormant stage that continues as long as adverse conditions persist. Artemia embryos in diapause and quiescence are remarkably resistant to environmental and physiological stressors, withstanding desiccation, cold, heat, oxidation, ultraviolet radiation, and years of anoxia at ambient temperature when fully hydrated. Cysts have adapted to stress in several ways; they are surrounded by a rigid cell wall impermeable to most chemical compounds and which functions as a shield against ultraviolet radiation. Artemia cysts contain large amounts of trehalose, a non-reducing sugar thought to preserve membranes and proteins during desiccation by replacing water molecules and/or contributing to vitrification. Late embryogenesis abundant proteins similar to those in seeds and other anhydrobiotic organisms are found in cysts, and they safeguard cell organelles and proteins during desiccation. Artemia cysts contain abundant amounts of p26, a small heat shock protein, and artemin, a ferritin homologue, both ATP-independent molecular chaperones important in stress tolerance. The evidence provided in this review supports the conclusion that it is the interplay of these protective elements that make Artemia one of the most stress tolerant of all metazoan organisms.

  6. Time Reversibility, Correlation Decay and the Steady State Fluctuation Relation for Dissipation

    Directory of Open Access Journals (Sweden)

    Denis J. Evans

    2013-04-01

    Full Text Available Steady state fluctuation relations for nonequilibrium systems are under intense investigation because of their important practical implications in nanotechnology and biology. However the precise conditions under which they hold need clarification. Using the dissipation function, which is related to the entropy production of linear irreversible thermodynamics, we show time reversibility, ergodic consistency and a recently introduced form of correlation decay, called T-mixing, are sufficient conditions for steady state fluctuation relations to hold. Our results are not restricted to a particular model and show that the steady state fluctuation relation for the dissipation function holds near or far from equilibrium subject to these conditions. The dissipation function thus plays a comparable role in nonequilibrium systems to thermodynamic potentials in equilibrium systems.

  7. All-optical four-state magnetization reversal in (Ga,Mn)As ferromagnetic semiconductors

    CERN Document Server

    Kapetanakis, M D; Piermarocchi, C; Wang, J; Perakis, I E

    2011-01-01

    Using density matrix equations of motion and a tight-binding band calculation, we predict all-optical switching between four metastable magnetic states of (III,Mn)As ferromagnets. This switching is initiated non-thermally within 100fs, during nonlinear coherent photoexcitation. For a single optical pulse, magnetization reversal is completed after $\\sim$100 ps and controlled by the coherent femtosecond photoexcitation. Our predicted switching comes from magnetic nonlinearities triggered by a femtosecond magnetization tilt that is sensitive to un--adiabatic light--induced spin interactions.

  8. Detection of a large Be circumstellar disk during X-ray quiescence of XTE J1946+274

    CERN Document Server

    Arabaci, M Ozbey; Gutierrez-Soto, J; Zurita, C; Nespoli, E; Suso, J; Kiaeerad, F; Garcia-Rojas, J; Kiziloglu, U

    2014-01-01

    We present a multiwavelength study of the Be/X-ray binary system XTE J1946+274 with the main goal of better characterizing its behavior during X-ray quiescence. We aim to shed light on the mechanism which triggers the X-ray activity for this source. XTE J1946+274 was observed by Chandra-ACIS during quiescence in 2013 March 12. In addition, this source has been monitored from the ground-based astronomical observatories of El Teide (Tenerife, Spain), Roque de los Muchachos (La Palma, Spain) and Sierra Nevada (Granada, Spain) since 2011 September, and from the TUBITAK National Observatory (Antalya, Turkey) since 2005 April. We have performed spectral and photometric temporal analyses in order to investigate the quiescent state and transient behavior of this binary system. In 2006, a long mass ejection event took place from the Be star, lasting for about seven years. We also found that a large Be circumstellar disk was present during quiescence, although major X-ray activity was not observed. We made an attempt t...

  9. The conserved HDAC Rpd3 drives transcriptional quiescence in S. cerevisiae

    Directory of Open Access Journals (Sweden)

    Jeffrey N. McKnight

    2015-12-01

    Full Text Available Quiescence is a ubiquitous cell cycle stage conserved from microbes through humans and is essential to normal cellular function and response to changing environmental conditions. We recently reported a massive repressive event associated with quiescence in Saccharomyces cerevisiae, where Rpd3 establishes repressive chromatin structure that drives transcriptional shutoff [6]. Here, we describe in detail the experimental procedures, data collection, and data analysis related to our characterization of transcriptional quiescence in budding yeast (GEO: GSE67151. Our results provide a bona fide molecular event driven by widespread changes in chromatin structure through action of Rpd3 that distinguishes quiescence as a unique cell cycle stage in S. cerevisiae.

  10. Consecutive reversible ionization-recombination reactions and ionic charge state distribution of Au plasma

    Institute of Scientific and Technical Information of China (English)

    ZHU Zhiyan; ZHU Zhenghe; TANG Changhuan; TANG Yongjian; GAO Tao

    2005-01-01

    The present work proposes kinetics of ionization-recombination to study the charge state distribution of Au plasma. The first step is to calculate the average lifetime, energy level structure, degeneracy and partition function of Au48+―Au52+ by relativistic quantum mechanics, and next to compute the equilibrium constant and the second-order recombination rate constant by statistical thermodynamics. Based on these data, the differential equations of consecutive reversible ionization-recombination reactions are solved from which the charge state distribution and its average charge are derived. Finally, the influence of electron temperature and density on average charge is given in this paper. It is called the first-principle theory, for no experimental data are needed.

  11. Modulation of a solid-state reversible fluorescent photoswitching based on a controllable photochromic pyrazolones

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Hu; Guo, Jixi [Key Laboratory of Material and Technology for Clean Energy, Ministry of Education, Key Laboratory of Advanced Functional Materials, Autonomous Region, Institute of Applied Chemistry, Xinjiang University, Urumqi 830046, Xinjiang (China); Jia, Dianzeng, E-mail: jdz@xju.edu.cn [Key Laboratory of Material and Technology for Clean Energy, Ministry of Education, Key Laboratory of Advanced Functional Materials, Autonomous Region, Institute of Applied Chemistry, Xinjiang University, Urumqi 830046, Xinjiang (China); Guo, Mingxi; Le, Fuhe; Liu, Lang; Wu, Dongling [Key Laboratory of Material and Technology for Clean Energy, Ministry of Education, Key Laboratory of Advanced Functional Materials, Autonomous Region, Institute of Applied Chemistry, Xinjiang University, Urumqi 830046, Xinjiang (China); Li, Feng [State Laboratory of Surface and Interface Science and Technology, School of Materials and Chemical Engineering, Zhengzhou University of Light Industry, Zhengzhou 450002, Henan (China); University of Texas, M. D. Anderson Cancer Center, Houston, TX 77002 (United States)

    2014-08-15

    A novel solid-state reversible fluorescence photoswitching system (FPS) based on photochromism of photochromic pyrazolones has been developed by employing phosphor Sr{sub 2}P{sub 2}O{sub 7} co-doped with europium ion and chlorine ion (Sr{sub 2}P{sub 2}O{sub 7}–EC) and 1,3-diphenyl-4-(3-chlorobenzal)-5-hydroxypyrazole-4-phenylsemicarbazone (1a) as the fluorescence dye and the photochromic compound, respectively. With carefully selected components, the absorption band of the keto-form photochromic pyrazolones well overlaps with the emission peak of Sr{sub 2}P{sub 2}O{sub 7}–EC. The fluorescence emission intensity of Sr{sub 2}P{sub 2}O{sub 7}–EC is efficiently modulated by the photoisomerization of 1a with controlling the exposure time in the solid state. The fluorescence photoswitching system displayed high fluorescence quenching efficiency and remarkable fatigue resistance. It can be repeated 7 cycles without observable the changes of emission intensity. A fluorescence quenching efficiency can be achieved with a reversible colour change from white to yellow. - Graphical abstract: A novel fluorescence photoswitching system based on doping inorganic fluorescence dye into photochromic pyrazolones was constructed successfully. Its fluorescence emission could be efficiently modulated by the photoisomerization of pyrazolones. - Highlights: • A solid-state fluorescence photoswitching material was prepared. • Photoswitching is due to energy transfer between pyrazolone and fluorescence dye. • It exhibits excellent fluorescence contrast and fatigue resistance in the solid state.

  12. Pseudo-time-reversal symmetry and topological edge states in two-dimensional acoustic crystals.

    Science.gov (United States)

    Mei, Jun; Chen, Zeguo; Wu, Ying

    2016-09-02

    We propose a simple two-dimensional acoustic crystal to realize topologically protected edge states for acoustic waves. The acoustic crystal is composed of a triangular array of core-shell cylinders embedded in a water host. By utilizing the point group symmetry of two doubly degenerate eigenstates at the Γ point, we can construct pseudo-time-reversal symmetry as well as pseudo-spin states in this classical system. We develop an effective Hamiltonian for the associated dispersion bands around the Brillouin zone center, and find the inherent link between the band inversion and the topological phase transition. With numerical simulations, we unambiguously demonstrate the unidirectional propagation of acoustic edge states along the interface between a topologically nontrivial acoustic crystal and a trivial one, and the robustness of the edge states against defects with sharp bends. Our work provides a new design paradigm for manipulating and transporting acoustic waves in a topologically protected manner. Technological applications and devices based on our design are expected in various frequency ranges of interest, spanning from infrasound to ultrasound.

  13. Hubble COS Spectroscopy of the Dwarf Nova CW Mon: The White Dwarf in Quiescence?

    Science.gov (United States)

    Hause, Connor; Sion, Edward M.; Godon, Patrick; Gänsicke, Boris T.; Szkody, Paula; de Martino, Domitilla; Pala, Anna

    2017-08-01

    We present a synthetic spectral analysis of the HST COS spectrum of the U Geminorum-type dwarf nova CW Mon, taken during quiescence as part of our COS survey of accreting white dwarfs (WDs) in Cataclysmic Variables. We use a synthetic photosphere and optically thick accretion disk spectra to model the COS spectrum as well as archival IUE spectra obtained decades ago, when the system was in an even deeper quiescent state. Assuming a reddening of E(B-V) = 0.06, an inclination of 60° (CW Mon has eclipses of the accretion disk), and a WD mass of 0.8 {M}⊙ , our results indicate the presence of a 22-27,000 K WD and a low mass accretion rate \\dot{M}≲ {10}-10 {M}⊙ {{yr}}-1, for a derived distance of ˜200 to ˜300 pc. Based on observations made with the NASA-Hubble Space Telescope.

  14. Signalling couples hair follicle stem cell quiescence with reduced histone H3 K4/K9/K27me3 for proper tissue homeostasis.

    Science.gov (United States)

    Lee, Jayhun; Kang, Sangjo; Lilja, Karin C; Colletier, Keegan J; Scheitz, Cornelia Johanna Franziska; Zhang, Ying V; Tumbar, Tudorita

    2016-04-15

    Mechanisms of plasticity to acquire different cell fates are critical for adult stem cell (SC) potential, yet are poorly understood. Reduced global histone methylation is an epigenetic state known to mediate plasticity in cultured embryonic SCs and T-cell progenitors. Here we find histone H3 K4/K9/K27me3 levels actively reduced in adult mouse skin and hair follicle stem cells (HFSCs) during G0 quiescence. The level of marks over specific gene promoters did not correlate to mRNA level changes in quiescent HFSCs. Skin hypomethylation during quiescence was necessary for subsequent progression of hair homeostasis (cycle). Inhibiting BMP signal, a known HFSC anti-proliferative factor, elevated HFSC methylation in vivo during quiescence prior to proliferation onset. Furthermore, removal of proliferation factors and addition of BMP4 reduced histone methylases and increased demethylases mRNAs in cultured skin epithelial cells. We conclude that signalling couples hair follicle stem cell quiescence with reduced H3 K4/K9/K27me3 levels for proper tissue homeostasis.

  15. SOAR observations of the high-viscosity accretion disc of the dwarf nova V4140 Sagitarii in quiescence and in outburst

    CERN Document Server

    Baptista, Raymundo; Oliveira, Alexandre S

    2016-01-01

    We report the analysis of 22 B-band light curves of the dwarf nova V4140 Sgr obtained with SOI/SOAR during two nights along the decline of a superoutburst in 2006 Sep 12-24 and in quiescence over 50 days following the superoutburst. Three-dimensional eclipse mapping of the outburst light curves indicates that the accretion disc is elliptical (eccentricity e=0.13) and that superhump maximum occurs when the mass donor star is aligned with the bulge of the elliptical disc. The accretion disc is geometrically thin both in outburst and in quiescence; it fills the primary Roche lobe in outburst and shrinks to about half this size in quiescence. The stability of the eclipse shape, width and depth along quiescence and the derived disc surface brightness distribution indicate that the quiescent accretion disc is in a high-viscosity, steady-state. Flickering mapping of the quiescent data reveal that the low-frequency flickering arises from an azimuthally-extended stream-disc impact region at disc rim and from the inner...

  16. A transcriptional program mediating entry into cellular quiescence.

    Directory of Open Access Journals (Sweden)

    Helen Liu

    2007-06-01

    Full Text Available The balance of quiescence and cell division is critical for tissue homeostasis and organismal health. Serum stimulation of fibroblasts is well studied as a classic model of entry into the cell division cycle, but the induction of cellular quiescence, such as by serum deprivation (SD, is much less understood. Here we show that SS and SD activate distinct early transcriptional responses genome-wide that converge on a late symmetric transcriptional program. Several serum deprivation early response genes (SDERGs, including the putative tumor suppressor genes SALL2 and MXI1, are required for cessation of DNA synthesis in response to SD and induction of additional SD genes. SDERGs are coordinately repressed in many types of human cancers compared to their normal counterparts, and repression of SDERGs predicts increased risk of cancer progression and death in human breast cancers. These results identify a gene expression program uniquely responsive to loss of growth factor signaling; members of SDERGs may constitute novel growth inhibitors that prevent cancer.

  17. Reversible adenylylation of glutamine synthetase is dynamically counterbalanced during steady-state growth of Escherichia coli.

    Science.gov (United States)

    Okano, Hiroyuki; Hwa, Terence; Lenz, Peter; Yan, Dalai

    2010-12-03

    Glutamine synthetase (GS) is the central enzyme for nitrogen assimilation in Escherichia coli and is subject to reversible adenylylation (inactivation) by a bifunctional GS adenylyltransferase/adenylyl-removing enzyme (ATase). In vitro, both of the opposing activities of ATase are regulated by small effectors, most notably glutamine and 2-oxoglutarate. In vivo, adenylyltransferase (AT) activity is critical for growth adaptation when cells are shifted from nitrogen-limiting to nitrogen-excess conditions and a rapid decrease of GS activity by adenylylation is needed. Here, we show that the adenylyl-removing (AR) activity of ATase is required to counterbalance its AT activity during steady-state growth under both nitrogen-excess and nitrogen-limiting conditions. This conclusion was established by studying AR(-)/AT(+) mutants, which surprisingly displayed steady-state growth defects in nitrogen-excess conditions due to excessive GS adenylylation. Moreover, GS was abnormally adenylylated in the AR(-) mutants even under nitrogen-limiting conditions, whereas there was little GS adenylylation in wild-type strains. Despite the importance of AR activity, we establish that AT activity is significantly regulated in vivo, mainly by the cellular glutamine concentration. There is good general agreement between quantitative estimates of AT regulation in vivo and results derived from previous in vitro studies except at very low AT activities. We propose additional mechanisms for the low AT activities in vivo. The results suggest that dynamic counterbalance by reversible covalent modification may be a general strategy for controlling the activity of enzymes such as GS, whose physiological output allows adaptation to environmental fluctuations.

  18. Fluorescence via Reverse Intersystem Crossing from Higher Triplet States in a Bisanthracene Derivative

    CERN Document Server

    Sato, Tohru; Haruta, Naoki; Pu, Yong-Jin

    2016-01-01

    To elucidate the high external quantum efficiency observed for organic light-emitting diodes using a bisanthracene derivative, BD1, as the emitting molecule, off-diagonal vibronic coupling constants (VCCs) between the excited states of BD1, which govern non-radiative transition rates, were calculated employing time-dependent density functional theory. The VCCs were analysed based on the concept of vibronic coupling density. The VCC calculations suggest a fluorescence via higher triplets (FvHT) mechanism, which entails the conversion of a T$_4$ exciton generated during electrical excitation into an S$_2$ exciton via reverse intersystem crossing (RISC); moreover, the S$_2$ exciton relaxes to a fluorescent S$_1$ exciton because of large vibronic coupling between S$_2$ and S$_1$. This mechanism is valid as long as the relaxation of triplet states higher than T$_1$ to lower states is suppressed. The symmetry-controlled thermally activated delayed fluorescence (SC-TADF) and inverted singlet and triplet (iST) struct...

  19. Anomalous electric birefringence behavior of sonicated DNA fragments as observed in reversing-pulse transients and steady-state sign reversal: a multicomponent approach.

    Science.gov (United States)

    Yamaoka, Kiwamu

    2007-04-15

    Anomalous electric birefringence signals of a sonicated and column-fractionated medium-size calf thymus DNA sample (bp=570) in Na(+) solutions were measured at 7 degrees C. The reversing-pulse electric birefringence (RPEB) signal pattern was theoretically calculated in the low electric field region for two axially symmetric models coexisting in equilibrium in solution. The RPEB theory is based on the electric dipole moment due to ion-fluctuation along the longitudinal direction and the electric polarizability anisotropy (Deltaalpha'), together with various electric and optical parameters assigned to the models. An analytical method was developed for the steady-state birefringence of the two-component system in a wide range of electric fields. The NaDNA samples exhibit complex RPEB patterns mixed with negative- and positive-going profiles. An experimental RPEB signal of NaDNA at an absorbance (A(260)) of 8 was fitted to theoretical curve at weak electric fields. The anomalous RPEB signal was attributed to the component 2, which shows a dip in the buildup and another in the reverse processes with a positive sign and a larger relaxation time. For the component 1, a normal DNA profile with negative sign is associated with a narrow dip in the reverse and a faster relaxation time in the decay signal. The field-strength dependence of observed steady-state birefringence delta(infinity) could be fitted for NaDNA at A(260)=8 by the SUSID orientation function with saturated ionic and electronic moments. An apparent positive maximum and the sign reversal in delta(infinity) at weak electric fields is an interplay between the positive component 2 with positive optical factor Deltag and negative Deltaalpha' and the negative component 1 with negative Deltag and positive Deltaalpha'. Possible conformation of two DNA components involved in solution was estimated.

  20. Aedes aegypti pharate 1st instar quiescence affects larval fitness and metal tolerance.

    Science.gov (United States)

    Perez, Mario H; Noriega, Fernando G

    2012-06-01

    The eggs of the mosquito Aedes aegypti possess the ability to undergo an extended quiescence hosting a fully developed 1st instar larvae within the chorion. As a result of this life history trait pharate larvae can withstand months of quiescence inside the egg where they depend on stored maternal reserves. A. aegypti mosquitoes are frequently associated with urban habitats that may contain significant metal pollution. Therefore, the duration of quiescence and extent of nutritional depletion may affect the physiology and survival of larvae that hatch in a suboptimal habitat. The aim of this study was to determine the effect of an extended quiescence on larval nutrient reserves and the subsequent effects of metal exposure on larval fitness, survival and development. We hypothesized that an extended quiescence would reduce nutritional reserves and alter the molecular response to metal exposure thereby reducing larval survival and altering larval development. As a molecular marker for metal stress responses, we evaluated transcriptional changes in the metallothionein gene (AaMtn) in response to quiescence and metal exposure. Extended 1st instar quiescence resulted in a significant decrease in lipid reserves and negatively affected larval fitness and development. AaMtn transcription and metal tolerance were compromised in first instars emerged from eggs that had undergone an extended quiescence. These findings suggest that newly emerged mosquito larvae that had survived a relatively long pharate 1st instar quiescence (as might occur during a dry season) are more vulnerable to environmental stress. Pharate 1st instar quiescence could have implications for vector control strategies. Newly emerged mosquito larvae at the end of the dry season or start of the wet season are physiologically compromised, and therefore potentially more susceptible to vector control strategies than mosquito larvae hatched subsequently throughout the wet season. Published by Elsevier Ltd.

  1. Quiescence does not affect p53 and stress response by irradiation in human lung fibroblasts

    Energy Technology Data Exchange (ETDEWEB)

    Dai, Jiawen [Molecular Radiobiology Laboratory, Division of Cellular and Molecular Research (Singapore); Itahana, Koji, E-mail: koji.itahana@duke-nus.edu.sg [Cancer and Stem Cell Biology Program, Duke-NUS Graduate Medical School (Singapore); Baskar, Rajamanickam, E-mail: r.baskar@nccs.com.sg [Molecular Radiobiology Laboratory, Division of Cellular and Molecular Research (Singapore); Department of Radiation Oncology, National Cancer Centre (Singapore)

    2015-02-27

    Cells in many organs exist in both proliferating and quiescent states. Proliferating cells are more radio-sensitive, DNA damage pathways including p53 pathway are activated to undergo either G{sub 1}/S or G{sub 2}/M arrest to avoid entering S and M phase with DNA damage. On the other hand, quiescent cells are already arrested in G{sub 0}, therefore there may be fundamental difference of irradiation response between proliferating and quiescent cells, and this difference may affect their radiosensitivity. To understand these differences, proliferating and quiescent human normal lung fibroblasts were exposed to 0.10–1 Gy of γ-radiation. The response of key proteins involved in the cell cycle, cell death, and metabolism as well as histone H2AX phosphorylation were examined. Interestingly, p53 and p53 phosphorylation (Ser-15), as well as the cyclin-dependent kinase inhibitors p21 and p27, were induced similarly in both proliferating and quiescent cells after irradiation. Furthermore, the p53 protein half-life, and expression of cyclin A, cyclin E, proliferating cell nuclear antigen (PCNA), Bax, or cytochrome c expression as well as histone H2AX phosphorylation were comparable after irradiation in both phases of cells. The effect of radioprotection by a glycogen synthase kinase 3β inhibitor on p53 pathway was also similar between proliferating and quiescent cells. Our results showed that quiescence does not affect irradiation response of key proteins involved in stress and DNA damage at least in normal fibroblasts, providing a better understanding of the radiation response in quiescent cells, which is crucial for tissue repair and regeneration. - Highlights: • p53 response by irradiation was similar between proliferating and quiescent cells. • Quiescent cells showed similar profiles of cell cycle proteins after irradiation. • Radioprotection of GSK-3β inhibitor caused similar effects between these cells. • Quiescence did not affect p53 response despite its

  2. The cellular prion protein: a player in immunological quiescence

    Directory of Open Access Journals (Sweden)

    Maren Kolltveit Bakkebø

    2015-09-01

    Full Text Available Despite intensive studies since the 1990s, the physiological role of the cellular prion protein (PrPC remains elusive. Here, we present a novel concept suggesting that PrPC contributes to immunological quiescence in addition to cell protection. PrPC is highly expressed in diverse organs that by multiple means are particularly protected from inflammation, such as the brain, eye, placenta, pregnant uterus and testes, while at the same time it is expressed in most cells of the lymphoreticular system. In this paradigm, PrPC serves two principal roles: to modulate the inflammatory potential of immune cells and to protect vulnerable parenchymal cells against noxious insults generated through inflammation. Here we review studies of PrPC physiology in view of this concept.

  3. Evaluation of a seismic quiescence pattern in southeastern sicily

    Science.gov (United States)

    Mulargia, F.; Broccio, F.; Achilli, V.; Baldi, P.

    1985-07-01

    Southeastern Sicily experienced a very peculiar seismic activity in historic times, with a long series of ruinous earthquakes. A last large event, with magnitude probably in excess of 7.5, occurred on Jan., 11, 1693, totally destroying the city of Catania and killing 60,000 people. Only a few moderate events were reported since then, and a seismic gap issue has been proposed on this basis. A close scrutiny of the available data further shows that all significant seismic activity ceased after year 1850, suggesting one of the largest quiescence patterns ever encountered. This is examined together with the complex tectonic setting of the region, characterized by a wrenching mechanism with most significant seismicity located in its northern graben structure. An attempt to ascertain the imminence and the size of a future earthquake through commonly accepted empirical relations based on size and duration of the quiescence pattern did not provide any feasible result. A precision levelling survey which we recently completed yielded a relative subsidence of ~ 3 mm/yr, consistent with an aseismic slip on the northern graben structure at a rate of ~ 15 mm/yr. Comparing these results with sedimentological and tidal data suggests that the area is undergoing an accelerated deformation process; this issue is further supported by Rikitake's ultimate strain statistics. If the imminence of a damaging ( M = 5.4) event is strongly favoured by Weibull statistics applied to the time series of occurrence of large events, the accumulated strain does not appear sufficient for a large earthquake ( M ⪸ 7.0). Within the limits of reliability of present semi-empirical approaches we conclude that the available evidence is consistent with the occurrence of a moderate-to-large ( M ≅ 6.0) event in the near future. Several questions regarding the application of simple models to real (and complex) tectonic settings remain nevertheless unanswered.

  4. Reverse Mortgage Participation in the United States: Evidence from a National Study

    Directory of Open Access Journals (Sweden)

    Swarn Chatterjee

    2016-03-01

    Full Text Available This paper uses the most recent wave of a nationally representative dataset to examine the factors associated with elderly homeowners’ decision to obtain reverse mortgage loans. The findings of this study suggest that very few homeowners participated in the reverse mortgage market, and homeowners younger than 67 were less likely to have reverse mortgage loans. However, homeowners who were risk averse, and homeowners in the two highest quartiles of net worth were more likely to have reverse mortgage loans. Further analyses reveal that among the reverse mortgage participants, homeowners with long-term care insurance coverage were less likely to have reverse mortgage loans. Implications for financial economists, financial planners, policy-makers, and scholars of retirement economics are included.

  5. Loss-tolerant state engineering for quantum-enhanced metrology via the reverse Hong-Ou-Mandel effect.

    Science.gov (United States)

    Ulanov, Alexander E; Fedorov, Ilya A; Sychev, Demid; Grangier, Philippe; Lvovsky, A I

    2016-06-21

    Highly entangled quantum states, shared by remote parties, are vital for quantum communications and metrology. Particularly promising are the N00N states-entangled N-photon wavepackets delocalized between two different locations-which outperform coherent states in measurement sensitivity. However, these states are notoriously vulnerable to losses, making them difficult to both share them between remote locations and recombine in order to exploit interference effects. Here we address this challenge by utilizing the reverse Hong-Ou-Mandel effect to prepare a high-fidelity two-photon N00N state shared between two parties connected by a lossy optical medium. We measure the prepared state by two-mode homodyne tomography, thereby demonstrating that the enhanced phase sensitivity can be exploited without recombining the two parts of the N00N state. Finally, we demonstrate the application of our method to remotely prepare superpositions of coherent states, known as Schrödinger's cat states.

  6. Loss-tolerant state engineering for quantum-enhanced metrology via the reverse Hong-Ou-Mandel effect

    Science.gov (United States)

    Ulanov, Alexander E.; Fedorov, Ilya A.; Sychev, Demid; Grangier, Philippe; Lvovsky, A. I.

    2016-06-01

    Highly entangled quantum states, shared by remote parties, are vital for quantum communications and metrology. Particularly promising are the N00N states--entangled N-photon wavepackets delocalized between two different locations--which outperform coherent states in measurement sensitivity. However, these states are notoriously vulnerable to losses, making them difficult to both share them between remote locations and recombine in order to exploit interference effects. Here we address this challenge by utilizing the reverse Hong-Ou-Mandel effect to prepare a high-fidelity two-photon N00N state shared between two parties connected by a lossy optical medium. We measure the prepared state by two-mode homodyne tomography, thereby demonstrating that the enhanced phase sensitivity can be exploited without recombining the two parts of the N00N state. Finally, we demonstrate the application of our method to remotely prepare superpositions of coherent states, known as Schrödinger's cat states.

  7. Reverse cholesterol transport: its contribution to cholesterol catabolism in normal and disease states.

    Science.gov (United States)

    Loh, K C; Tan, M H

    1996-10-01

    To review the reverse cholesterol transport (RCT) model and its contribution to cholesterol catabolism in normal and disease states. Pertinent articles were identified through a MEDLINE search of the English language literature from 1983 to 1995, followed by a manual search of the bibliographies of pertinent articles. Review articles, laboratory and clinical studies and case reports. The physiology of the RCT pathway as well as alterations observed in individuals with diseases or lifestyle changes were reviewed. Data were derived mainly from laboratory studies and clinical observations. The RCT model is proposed to explain the removal of excess cholesterol from extrahepatic tissues and its delivery to liver for catabolism. This involves several regulated steps mediated by the plasma apolipoproteins and two key enzymes, lecithin:cholesterol acyltransferase (LCAT) and cholesteryl ester transfer protein (CETP). In essence free cholesterol in peripheral tissues is taken up by nascent high density lipoprotein (HDL) particles, converted to cholesteryl esters (by LCAT), and then transferred to apo B-containing lipoproteins (by CETP) for hepatic removal. Altered cholesterol catabolism may occur in individuals with disorders of a genetic or acquired nature as well as lifestyle changes, as a result of alterations in one of several of the putative steps or enzymes involved in RCT. The proposed antiatherogenic role of RCT remains to be validated as a review of the possible alterations noted in various disorders showed conflicting results in atherogenic propensity.

  8. Mean-field studies of time reversal breaking states in super-heavy nuclei with the Gogny force

    Energy Technology Data Exchange (ETDEWEB)

    Robledo, L. M., E-mail: luis.robledo@uam.es [Departamento Física Teórica, Facultad de Ciencias, Universidad Autónoma de Madrid, E-28049 Madrid (Spain)

    2015-10-15

    Recent progress on the description of time reversal breaking (odd mass and multi-quasiparticle excitation) states in super-heavy nuclei within a mean field framework and using several flavors of the Gogny interaction is reported. The study includes ground and excited states in selected odd mass isotopes of nobelium and mendelevium as well as high K isomeric states in {sup 254}No. These are two and four-quasiparticle excitations that are treated in the same self-consistent HFB plus blocking framework as the odd mass states.

  9. Loss-tolerant state engineering for quantum-enhanced metrology via the reverse Hong–Ou–Mandel effect

    Science.gov (United States)

    Ulanov, Alexander E.; Fedorov, Ilya A.; Sychev, Demid; Grangier, Philippe; Lvovsky, A. I.

    2016-01-01

    Highly entangled quantum states, shared by remote parties, are vital for quantum communications and metrology. Particularly promising are the N00N states—entangled N-photon wavepackets delocalized between two different locations—which outperform coherent states in measurement sensitivity. However, these states are notoriously vulnerable to losses, making them difficult to both share them between remote locations and recombine in order to exploit interference effects. Here we address this challenge by utilizing the reverse Hong–Ou–Mandel effect to prepare a high-fidelity two-photon N00N state shared between two parties connected by a lossy optical medium. We measure the prepared state by two-mode homodyne tomography, thereby demonstrating that the enhanced phase sensitivity can be exploited without recombining the two parts of the N00N state. Finally, we demonstrate the application of our method to remotely prepare superpositions of coherent states, known as Schrödinger's cat states. PMID:27324115

  10. A sustained depressive state promotes a guanfacine reversible susceptibility to alcohol seeking in rats.

    Science.gov (United States)

    Riga, Danai; Schmitz, Leanne J M; van der Harst, Johanneke E; van Mourik, Yvar; Hoogendijk, Witte J G; Smit, August B; De Vries, Taco J; Spijker, Sabine

    2014-04-01

    High rates of comorbidity between alcohol use disorder (AUD) and major depressive disorder (MDD) are reported. Preclinical models examining effects of primary depression on secondary AUD are currently absent, preventing adequate testing of drug treatment. Here, we combined social defeat-induced persistent stress (SDPS) and operant alcohol self-administration (SA) paradigms to assess causality between these two neuropsychiatric disorders. We then exploited guanfacine, an FDA-approved adrenergic agent reported to reduce drug craving in humans, against SDPS-induced modulation of operant alcohol SA. Wistar rats were socially defeated and isolated for a period of ≥9 weeks, during which depression-like symptomatology (cognitive and social behavioral symptoms) was assessed. Subsequently, animals were subjected to a 5-month operant alcohol SA paradigm, examining acquisition, motivation, extinction, and cue-induced reinstatement of alcohol seeking. The effects of guanfacine on motivation and relapse were measured at >6 months following defeat. SDPS rats exhibited significant disruption of social and cognitive behavior, including short-term spatial and long-term social memory, several months following defeat. Notably, SDPS increased motivation to obtain alcohol, and cue-induced relapse vulnerability. Guanfacine reversed the SDPS-induced effects on motivation and relapse. Together, our model mimics core symptomatology of a sustained depressive-like state and a subsequent vulnerability to alcohol abuse. We show that SDPS is strongly associated with an enhanced motivation for alcohol intake and relapse. Finally, we show that the clinically employed drug guanfacine has potential as a novel treatment option in comorbid patients, as it effectively reduced the enhanced sensitivity to alcohol and alcohol-associated stimuli.

  11. Vouchers in Fragile States: Reducing Barriers to Long-Acting Reversible Contraception in Yemen and Pakistan.

    Science.gov (United States)

    Boddam-Whetham, Luke; Gul, Xaher; Al-Kobati, Eman; Gorter, Anna C

    2016-08-11

    In conflict-affected states, vouchers have reduced barriers to reproductive health services and have enabled health programs to use targeted subsidies to increase uptake of specific health services. Vouchers can also be used to channel funds to public- and private-service providers and improve service quality. The Yamaan Foundation for Health and Social Development in Yemen and the Marie Stopes Society (MSS) in Pakistan-both working with Options Consultancy Services-have developed voucher programs that subsidize voluntary access to long-acting reversible contraceptives (LARCs) and permanent methods (PMs) of family planning in their respective fragile countries. The programs focus on LARCs and PMs because these methods are particularly difficult for poor women to access due to their cost and to provider biases against offering them. Using estimates of expected voluntary uptake of LARCs and PMs for 2014 based on contraceptive prevalence rates, and comparing these with uptake of LARCs and PMs through the voucher programs, we show the substantial increase in service utilization that vouchers can enable by contributing to an expanded method choice. In the governorate of Lahj, Yemen, vouchers for family planning led to an estimated 38% increase in 2014 over the expected use of LARCs and PMs (720 vs. 521 expected). We applied the same approach in 13 districts of Punjab, Khyber Pakhtunkhwa (KPK), and Sindh provinces in Pakistan. Our calculations suggest that vouchers enabled 10 times more women than expected to choose LARCs and PMs in 2014 in those areas of Pakistan (73,639 vs. 6,455 expected). Voucher programs can promote and maintain access to family planning services where existing health systems are hampered. Vouchers are a flexible financing approach that enable expansion of contraceptive choice and the inclusion of the private sector in service delivery to the poor. They can keep financial resources flowing where the public sector is prevented from offering services

  12. The Magnetization Reversal Processes Of Bulk (Nd, Y-(Fe, Co-B Alloy In The As-Quenched State

    Directory of Open Access Journals (Sweden)

    Dośpiał M.

    2015-09-01

    Full Text Available The magnetization reversal processes of bulk Fe64Co5Nd6Y6B19 alloy in the as-quenched state have been investigated. From the analysis of the initial magnetization curve and differential susceptibility versus an internal magnetic field it was deduced, that the main mechanism of magnetization reversal process is the pinning of domain walls at the grain’s boundaries of the Nd2Fe14B phase. Basing on the dependence of the reversible magnetization component as a function of magnetic field it was found that reversible rotation of a magnetic moment vector and motion of domain walls in multi-domain grains result in high initial values of the reversible component. The presence of at least two maxima on differential susceptibility of irreversible magnetization component in function of magnetic field imply existence of few pinning sites of domain walls in Fe64Co5Nd6Y6B19 alloy. The dominant interactions between particles have been determined on the basis of the Wohlfarth dependence. Such a behavior of Wohlfarth’s plot implies that the dominant interaction between grains becomes short range exchange interactions.

  13. A Photometry Campaign for IR Geminorum in Quiescence

    Institute of Scientific and Technical Information of China (English)

    Hai Fu; Zong-Yun Li; Kam-Ching Leung; Zhou-Sheng Zhang; Zi-Li Li; C. Martin Gaskell

    2004-01-01

    We report a V band photometry of the SU UMa star IR Gem at quiescence in January 2002. The observations were made with two telescopes spaced ~ 160° apart in longitude. Several photometric modulations have been found. One gives a period of 98.50(13) min, exactly equal to the orbital period determined spectroscopically. Two others occasionally strengthen and seem to be positive and negative superhumps with periods of 103.6(4) and 95.4(4) min, 5.2% longer and 3.1% shorter than the orbital period, respectively. A signal at ~ 0.6 c/d in the power spectrum is roughly consistent with the expected period of nodal precession of the disk. There is a puzzling peak at 0.21(3) c/d corresponding to the ~ 4.3 d sine wave seen in the raw light curve. We suspect it to be a beat frequency between the frequencies of apsidal and nodal precessions of the disk. Quasi-periodic cycles with amplitudes 0.15-0.6 mag can be seen in the light curve. The mechanism underlying this modulation is not clear.

  14. Search for Blue Compact Dwarf Galaxies During Quiescence

    CERN Document Server

    Almeida, J Sanchez; Amorin, R; Aguerri, J A; Sanchez-Janssen, R; Tenorio-Tagle, G

    2008-01-01

    Blue Compact Dwarf (BCD) galaxies are metal poor systems going through a major starburst that cannot last for long. We have identified galaxies which may be BCDs during quiescence (QBCD), i.e., before the characteristic starburst sets in or when it has faded away. These QBCD galaxies are assumed to be like the BCD host galaxies. The SDSS/DR6 database provides ~21500 QBCD candidates. We also select from SDSS/DR6 a complete sample of BCD galaxies to serve as reference. The properties of these two galaxy sets have been computed and compared. The QBCD candidates are thirty times more abundant than the BCDs, with their luminosity functions being very similar except for the scaling factor, and the expected luminosity dimming associated with the end of the starburst. QBCDs are redder than BCDs, and they have larger HII region based oxygen abundance. QBCDs also have lower surface brightness. The BCD candidates turn out to be the QBCD candidates with the largest specific star formation rate (actually, with the largest...

  15. Characteristics of women in the United States who use long-acting reversible contraceptive methods.

    Science.gov (United States)

    Kavanaugh, Megan L; Jerman, Jenna; Hubacher, David; Kost, Kathryn; Finer, Lawrence B

    2011-06-01

    To examine characteristics of U.S. women that are associated with use of long-acting reversible contraception and changes in these characteristics between 2002 and 2006-2008. We analyzed data from two nationally representative samples of women aged 15-44 in the National Survey of Family Growth, including 7,643 women in 2002 and 7,356 women in 2006-2008. We conducted simple and multinomial logistic regression analyses to identify demographic and reproductive health characteristics associated with use of long-acting reversible contraception. Long-acting reversible contraception (intrauterine devices and subdermal implants) use among U.S. women using contraception increased from 2.4% in 2002 to 5.6% in 2006-2008. The largest increases in long-acting reversible contraception use during this time occurred among the youngest and oldest age groups, non-Hispanic white and non-Hispanic African American women, foreign-born women, and those in the highest income group. High prevalence of long-acting reversible contraception use in 2006-2008 was seen among women who had given birth once or twice (10%), foreign-born women (8.8%), and Hispanic women (8.4%). After adjusting for key demographic and reproductive health characteristics, in comparison with users of other contraceptive methods and with those not using contraception who were at risk for unintended pregnancy, foreign-born women and women who experienced coitarche before age 18 were approximately twice as likely to be using long-acting reversible contraception as women without those characteristics. A more diverse population of women used long-acting reversible contraception in 2006-2008 compared with 2002. However, there is likely more potential for increased uptake, especially among populations historically not considered to be candidates for these methods.

  16. Origin of X-ray Emission from Transient Black Hole Candidates in Quiescence

    CERN Document Server

    Pszota, Gabor; Yuan, Feng; Cui, Wei

    2008-01-01

    We report results from a systematic study of X-ray emission from black hole transients in quiescence. In this state mass accretion is thought to follow the geometry of an outer optically thick, geometrically thin disc and an inner optically thin, geometrically thick radiatively inefficient accretion flow (RIAF). The inner flow is likely also coupled to the jets near the black hole that are often seen in such systems. The goal of the study is to see whether the X-ray emission in the quiescent state is mainly powered by the accretion flow or the jets. Using data from deep XMM-Newton observations of selected black hole transients, we have found that the quiescent X-ray spectra are, to a high precision, of power-law shape in the cases of GRO J1655-40 and V404 Cyg. Such spectra deviate significantly from the expected X-ray spectrum of the RIAF at very low accretion rates. On the other hand, they can naturally be explained by emission from the jets, if the emitting electrons follow a power-law spectral distribution...

  17. Multi-wavelength observations of IGR J17544-2619 from quiescence to outburst

    CERN Document Server

    Bozzo, E; Pradhan, P; Tomsick, J; Romano, P; Ferrigno, C; Chaty, S; Oskinova, L; Manousakis, A; Walter, R; Falanga, M; Campana, S; Stella, L; Ramolla, M; Chini, R

    2016-01-01

    In this paper we report on a long multi-wavelength observational campaign of the supergiant fast X-ray transient prototype IGR J17544-2619. A 150 ks-long observation was carried out simultaneously with XMM-Newton and NuSTAR, catching the source in an initial faint X-ray state and then undergoing a bright X-ray outburst lasting about 7 ks. We studied the spectral variability during outburst and quiescence by using a thermal and bulk Comptonization model that is typically adopted to describe the X-ray spectral energy distribution of young pulsars in high mass X-ray binaries. Although the statistics of the collected X-ray data were relatively high we could neither confirm the presence of a cyclotron line in the broad-band spectrum of the source (0.5-40 keV), nor detect any of the previously reported tentative detection of the source spin period. The monitoring carried out with Swift/XRT during the same orbit of the system observed by XMM-Newton and NuSTAR revealed that the source remained in a low emission state...

  18. Artificial Intelligence in Reverse Supply Chain Management: The State of the Art

    CERN Document Server

    Xing, Bo; Battle, Kimberly; Marwala, Tshildzi; Nelwamondo, Fulufhelo V

    2010-01-01

    Product take-back legislation forces manufacturers to bear the costs of collection and disposal of products that have reached the end of their useful lives. In order to reduce these costs, manufacturers can consider reuse, remanufacturing and/or recycling of components as an alternative to disposal. The implementation of such alternatives usually requires an appropriate reverse supply chain management. With the concepts of reverse supply chain are gaining popularity in practice, the use of artificial intelligence approaches in these areas is also becoming popular. As a result, the purpose of this paper is to give an overview of the recent publications concerning the application of artificial intelligence techniques to reverse supply chain with emphasis on certain types of product returns.

  19. From quiescence to proliferation : Cdk oscillations drive the mammalian cell cycle

    Directory of Open Access Journals (Sweden)

    Claude eGérard

    2012-11-01

    Full Text Available We recently proposed a detailed model describing the dynamics of the network of cyclin-dependent kinases (Cdks driving the mammalian cell cycle [Gérard, C. and Goldbeter, A. (2009. Temporal self-organization of the cyclin/Cdk network driving the mammalian cell cycle. Proc. Natl. Acad. Sci. USA 106, 21643-21648]. The model contains four modules, each centered around one cyclin/Cdk complex. Cyclin D/Cdk4-6 and cyclin E/Cdk2 promote progression in G1 and elicit the G1/S transition, respectively; cyclin A/Cdk2 ensures progression in S and the transition S/G2, while the activity of cyclin B/Cdk1 brings about the G2/M transition. This model shows that in the presence of sufficient amounts of growth factor the Cdk network is capable of temporal self-organization in the form of sustained oscillations, which correspond to the ordered, sequential activation of the various cyclin/Cdk complexes that control the successive phases of the cell cycle. The results suggest that the switch from cellular quiescence to cell proliferation corresponds to the transition from a stable steady state to sustained oscillations in the Cdk network. The transition depends on a finely tuned balance between factors that promote or hinder progression in the cell cycle. We show that the transition from quiescence to proliferation can occur in multiple ways that alter this balance. By resorting to bifurcation diagrams, we analyze the mechanism of oscillations in the Cdk network. Finally, we show that the complexity of the detailed model can be greatly reduced, without losing its key dynamical properties, by considering a skeleton model for the Cdk network. Using such a skeleton model for the mammalian cell cycle we show that positive feedback loops enhance the amplitude and the robustness of Cdk oscillations with respect to molecular noise. We compare the relative merits of the detailed and skeleton versions of the model for the Cdk network driving the mammalian cell cycle.

  20. Porphyrins in Reverse Micelles:the Side-chain Length and the Triplet-state Lifetime

    Institute of Scientific and Technical Information of China (English)

    Jun Hua YU; Yu Xiang WENG; Xue Song WANG; Lei ZHANG; Bao Wen ZHANG; Yi CAO

    2003-01-01

    Using bis(2-ethylhexyl) sodium sulfosuccinate (AOT) as surfactant, two amphiphilic porphyrin terminated with imidazole were studied in AOT/iso-octane/water reverse micelles, intending to mimic the relationship between microenvironments in organism and the amphiphilic properties of porphyrins for photodynamic therapy drugs.

  1. Discordant results from reverse sequence syphilis screening--five laboratories, United States, 2006-2010.

    Science.gov (United States)

    2011-02-11

    CDC recommends syphilis serologic screening with a nontreponemal test, such as the rapid plasma reagin (RPR) or Venereal Disease Research Laboratory (VDRL) test, to identify persons with possible untreated infection; this screening is followed by confirmation using one of several treponemal tests. Recently, the availability of automatable treponemal enzyme and chemiluminescence immunoassays (EIA/CIA) has led some laboratories to adopt a reverse sequence of screening in which a treponemal EIA/CIA is performed first, followed by testing of reactive sera with a nontreponemal test. To better understand the performance of reverse sequence screening for syphilis, CDC analyzed data from five laboratories that used reverse sequence screening during 2006-2010. This report describes the results of that analysis, which indicated that among sera reactive on initial screening with a treponemal EIA/CIA, 56.7% had a nonreactive RPR test. Among these discordant sera, 31.6% also were nonreactive by treponemal testing using Treponema pallidum particle agglutination (TP-PA) or fluorescent treponemal antibody absorbed (FTA-ABS) tests. Among discordant sera, the rate of nonreactive confirmatory treponemal tests was 2.9 times higher in a population with low prevalence of syphilis, suggesting that the low-prevalence population had a higher percentage of false-positive test results. Although CDC continues to recommend the traditional algorithm with reactive nontreponemal tests confirmed by treponemal testing, in this report CDC offers additional recommendations if reverse sequence syphilis screening is used.

  2. SOAR observations of the high-viscosity accretion disc of the dwarf nova V4140 Sagitarii in quiescence and in outburst

    Science.gov (United States)

    Baptista, Raymundo; Borges, Bernardo W.; Oliveira, Alexandre S.

    2016-12-01

    We report the analysis of 22 B-band light curves of the dwarf nova V4140 Sgr obtained with SOAR Optical Imager (SOI)/SOAR during two nights along the decline of a superoutburst in 2006 September 12-24 and in quiescence over 50 d following the superoutburst. 3D eclipse mapping of the outburst light curves indicates that the accretion disc is elliptical (eccentricity e = 0.13) and that superhump maximum occurs when the mass donor star is aligned with the bulge of the elliptical disc. The accretion disc is geometrically thin both in outburst and in quiescence; it fills the primary Roche lobe in the outburst and shrinks to about half this size in quiescence. The stability of the eclipse shape, width and depth along quiescence and the derived disc surface brightness distribution indicate that the quiescent accretion disc is in a high-viscosity, steady-state. Flickering mapping of the quiescent data reveals that the low-frequency flickering arises from an azimuthally extended stream-disc impact region at disc rim and from the innermost disc region, whereas the high-frequency flickering originates in the accretion disc. Assuming the disc-related flickering to be caused by fluctuations in the energy dissipation rate induced by magnetohydrodynamic turbulence (Geertsema & Achterberg), we find that the quiescent disc viscosity parameter is large, α ≃ 0.2-0.4, at all radii. The high-viscosity quiescent disc and the inferred low disc temperatures in superoutburst are inconsistent with expectations of the disc-instability model, and lead to the conclusion that the outbursts of V4140 Sgr are powered by mass transfer bursts from its donor star.

  3. Autophagy is required for G₁/G₀ quiescence in response to nitrogen starvation in Saccharomyces cerevisiae.

    Science.gov (United States)

    An, Zhenyi; Tassa, Amina; Thomas, Collin; Zhong, Rui; Xiao, Guanghua; Fotedar, Rati; Tu, Benjamin P; Klionsky, Daniel J; Levine, Beth

    2014-10-01

    In response to starvation, cells undergo increased levels of autophagy and cell cycle arrest but the role of autophagy in starvation-induced cell cycle arrest is not fully understood. Here we show that autophagy genes regulate cell cycle arrest in the budding yeast Saccharomyces cerevisiae during nitrogen starvation. While exponentially growing wild-type yeasts preferentially arrest in G₁/G₀ in response to starvation, yeasts carrying null mutations in autophagy genes show a significantly higher percentage of cells in G₂/M. In these autophagy-deficient yeast strains, starvation elicits physiological properties associated with quiescence, such as Snf1 activation, glycogen and trehalose accumulation as well as heat-shock resistance. However, while nutrient-starved wild-type yeasts finish the G₂/M transition and arrest in G₁/G 0₀ autophagy-deficient yeasts arrest in telophase. Our results suggest that autophagy is crucial for mitotic exit during starvation and appropriate entry into a G₁/G₀ quiescent state.

  4. Reversible Diffusion-Limited Reactions: "Chemical Equilibrium" State and the Law of Mass Action Revisited

    OpenAIRE

    Voituriez, R.; Moreau, M.; Oshanin, G.

    2004-01-01

    The validity of two fundamental concepts of classical chemical kinetics - the notion of "Chemical Equilibrium" and the "Law of Mass Action" - are re-examined for reversible \\textit{diffusion-limited} reactions (DLR), as exemplified here by association/dissociation $A+A \\rightleftharpoons B$ reactions. We consider a general model of long-ranged reactions, such that any pair of $A$ particles, separated by distance $\\mu$, may react with probability $\\omega_+(\\mu)$, and any $B$ may dissociate wit...

  5. New AIE-active pyrimidine-based boronfluoride complexes with high solid-state emission and reversible mechanochromism luminescence behavior.

    Science.gov (United States)

    Qi, Fen; Lin, Jianjian; Wang, Xiaoqing; Cui, Peng; Yan, Hui; Gong, Shuwen; Ma, Chunlin; Liu, Zhipeng; Huang, Wei

    2016-04-25

    A new family of pyrimidine-based BF2 complexes () with aggregation-induced emission (AIE) and mechanochromic luminescence properties were developed. These compounds exhibit intense fluorescence in their aggregation/solid-state resulting from their large Stokes shift and AIE. X-ray crystallographic analysis shows that the weak intermolecular interactions by fixing the molecular conformations of are responsible for the intense fluorescence in solid-state. In addition to their pronounced AIE behaviour, also exhibits a reversible chromic response to grinding, and a distinct red-shift of emission is observed. The high solid-state luminescence and grinding-stimuli response properties of these compounds make them potential candidates for smart materials.

  6. Reversal of spin polarization in Fe/GaAs (001) driven by resonant surface states: First-principles calculations

    OpenAIRE

    Chantis, Athanasios N; Belashchenko, Kirill D.; Smith, Darryl L.; Tsymbal, Evgeny Y.; van Schilfgaarde, Mark; Albers, Robert C

    2007-01-01

    A minority-spin resonant state at the Fe/GaAs(001) interface is predicted to reverse the spin polarization with voltage bias of electrons transmitted across this interface. Using a Green's function approach within the local spin density approximation we calculate spin-dependent current in a Fe/GaAs/Cu tunnel junction as a function of applied bias voltage. We find a change in sign of the spin polarization of tunneling electrons with bias voltage due to the interface minority-spin resonance. Th...

  7. [Signaling molecules and pathways involved in maintaining the quiescence of primordial follicles].

    Science.gov (United States)

    Hu, Liao-Liao; Xiang, Cheng; Zheng, Li-Ping

    2015-02-25

    Reproductive lifespan in female mammals is related to the size of primordial follicles pool, which relies on the balance between activated and quiescent primordial follicles. Therefore, the molecular mechanisms of recruiting and maintaining quiescence of primordial follicles have become hot research topics recently. Multiple studies have shown that genetic mutations, local ovarian autocrine and paracrine factors, proto-oncogene and tumor-suppressor genes are involved in the maintenance of balance between quiescent and activated primordial follicles. In the present review, we summarize recent research progress of the important signaling molecules and pathways that maintain the quiescence of primordial follicles.

  8. Curious Variables Experiment (CURVE). CCD Photometry of QW Serpentis in Superoutburst and Quiescence

    CERN Document Server

    Olech, A; Zloczewski, K; Mularczyk, K; Wisniewski, M

    2003-01-01

    We report extensive photometry of the dwarf nova QW Ser throughout its 2003 February superoutburst till quiescence. During the superoutburst the star displayed clear superhumps with a mean period of Psh = 0.07703(4) days. In the quiescence we observed a double humped wave characterized by a period of P=0.07457(2) days. As both periods obey the Stolz-Schoembs relation with a period excess equal to 3.30+/-0.06% the latter period is interpreted as the orbital period of the binary system.

  9. High energy X-ray emission from recurrent novae in quiescence: T CrB

    CERN Document Server

    Luna, Gerardo J M; Mukai, Koji

    2007-01-01

    We present Suzaku X-ray observations of the recurrent nova T CrB in quiescence. T CrB is the first recurrent nova to be detected in the hard-X-ray band (E ~ 40.0 keV) during quiescence. The X-ray spectrum is consistent with cooling-flow emission emanating from an optically thin region in the boundary layer of an accretion disk around the white dwarf. The detection of strong stochastic flux variations in the light curve supports the interpretation of the hard X-ray emission as emanating from a boundary layer.

  10. XMM-Newton observations of the low-mass X-ray binary EXO 0748-676 in quiescence

    NARCIS (Netherlands)

    Trigo, M. Diaz; Boirin, L.; Costantini, E.; Mendez, M.; Parmar, A.

    2011-01-01

    The neutron star low-mass X-ray binary EXO 0748-676 started a transition from outburst to quiescence in August 2008, after more than 24 years of continuous accretion. The return of the source to quiescence has been monitored extensively by several X-ray observatories. Here, we report on four XMM-New

  11. State of the reverse osmosis membrane of sea water corso plant desalination (Algiers)

    Science.gov (United States)

    Abdessemed, D.; Hamouni, S.; Nezzal, G.

    2009-11-01

    Seawater reverse osmosis (SWRO) desalination is being increasingly emphasized as a strategy for conservation of limited resources of freshwater. Although desalination has been developed for the last few decades, the SWRO operation is still affected by membrane fouling. The membrane fouling of SWRO has a significant impact on operation of desalination plants. We follow the evolution of the permeate conductivity during three months of the sea water Corso (Algiers) plant desalination. The purpose of this work is to conduct an autopsy of fouled membranes in seawater using the scanning electron microscopy (SEM) coupled by an analysis EDX. This membrane shows a change of the surface morphology, which justifies the abrupt increase in the conductivity of the permeate in May 2006. In order to identify the nature of the fouling deposit, we analysed this deposit by Xrays diffraction (XRD).

  12. Perfect quantum state engineering by the combination of the counterdiabatic driving and the reverse-engineering technique

    Science.gov (United States)

    Wu, Qi-Cheng; Huang, Bi-Hua; Chen, Ye-Hong; Shi, Zhi-Cheng; Song, Jie; Xia, Yan

    2017-10-01

    We propose a method to design shortcuts to adiabaticity for implementing perfect quantum state engineering by the combination of the counterdiabatic driving and the reverse engineering technique. Based on the method, we can design simple schemes to realize the intended dynamics. For the sake of clearness, we apply this method to several examples including two-level, three-level and four-level system. We show that fast quantum state engineering can be realized by utilizing simply-designed auxiliary Hamiltonian. Furthermore, a suitable choice of the control parameters can eliminate the additional couplings in the introduced auxiliary Hamiltonian. Numerical simulation reveals that the constructed scheme is reliable and robust against various dissipation effects and the fluctuations of control parameters in current technology.

  13. Reversible control of kinesin activity and microtubule gliding speeds by switching the doping states of a conducting polymer support

    Energy Technology Data Exchange (ETDEWEB)

    Martin, Brett D [US Naval Research Laboratory, Code 6930, Washington, DC 20375 (United States); Velea, Luminita M [US Naval Research Laboratory, Code 6930, Washington, DC 20375 (United States); Soto, Carissa M [US Naval Research Laboratory, Code 6930, Washington, DC 20375 (United States); Whitaker, Craig M [US Naval Academy, Department of Chemistry, Annapolis, MD 21402 (United States); Gaber, Bruce P [US Naval Research Laboratory, Code 6930, Washington, DC 20375 (United States); Ratna, Banahalli [US Naval Research Laboratory, Code 6930, Washington, DC 20375 (United States)

    2007-02-07

    We describe a method for reversibly controlling the ATPase activity of streptavidin-linked kinesin by changing the doping states of a conducting polymer support. When the polymer (poly(CH{sub 2}OH-EDOT)) was electrochemically switched from its dedoped (semiconducting) state to its doped (conducting) state, the ATPase activity of the adsorbed kinesin complex decreased by 35% with a concomitant decrease in the gliding speeds of kinesin-driven microtubules. When the polymer was switched back to its original dedoped state, nearly identical increases were observed in the kinesin ATPase activity and microtubule speeds. Use of a fluorescent ATP substrate analogue showed that the total amount of kinesin adsorbed on the poly(CH{sub 2}OH-EDOT) surface remained constant as the doping state of the polymer was switched. The microtubules exhibited nearly identical speed differences on the doped and dedoped surfaces for both chemical and electrochemical doping methods. Michaelis-Menten modelling suggests that the doped surface acts as an 'uncompetitive inhibitor' of kinesin. This work represents an investigation into the phenomenon of an electrically switchable surface exerting a moderating effect on the activity of an adsorbed protein that does not contain a bound, electroactive metal ion.

  14. Reversible Luminescence Modulation upon an Electric Field on a Full Solid-State Device Based on Lanthanide Dimers.

    Science.gov (United States)

    Yi, Xiaohui; Shang, Jie; Pan, Liang; Tan, Hongwei; Chen, Bin; Liu, Gang; Huang, Gang; Bernot, Kevin; Guillou, Olivier; Li, Run-Wei

    2016-06-22

    Switching luminescence of lanthanide-based molecules through an external electric field is considered as a promising approach toward novel functional molecule-based devices. Classic routes use casted films and liquid electrolyte as media for redox reactions. Such protocol, even if efficient, is relatively hard to turn into an effective solid-state device. In this work, we explicitly synthesize lanthanide-based dimers whose luminescent behavior is affected by the presence of Cu(2+) ions. Excellent evaporability of the dimers and utilization of Cu(2+)-based solid-state electrolyte makes it possible to reproduce solution behavior at the solid state. Reversible modulation of Cu(2+) ions transport can be achieved by an electric field in a solid-state device, where lanthanide-related luminescence is driven by an electric field. These findings provide a proof-of-concept alternative approach for electrically driven modulation of solid-state luminescence and show promising potential for information storage media in the future.

  15. State of the art and review on the treatment technologies of water reverse osmosis concentrates.

    Science.gov (United States)

    Pérez-González, A; Urtiaga, A M; Ibáñez, R; Ortiz, I

    2012-02-01

    The growing demand for fresh water is partially satisfied by desalination plants that increasingly use membrane technologies and among them reverse osmosis to produce purified water. Operating with water recoveries from 35% to 85% RO plants generate huge volumes of concentrates containing all the retained compounds that are commonly discharged to water bodies and constitute a potentially serious threat to marine ecosystems; therefore there is an urgent need for environmentally friendly management options of RO brines. This paper gives an overview on the potential treatments to overcome the environmental problems associated to the direct discharge of RO concentrates. The treatment options have been classified according to the source of RO concentrates and the maturity of the technologies. For the sake of clarity three different sources of RO concentrates are differentiated i) desalination plants, ii) tertiary processes in WWTP, and iii) mining industries. Starting with traditional treatments such as evaporation and crystallization other technologies that have emerged in last years to reduce the volume of the concentrate before disposal and with the objective of achieving zero liquid discharge and recovery of valuable compounds from these effluents are also reviewed. Most of these emerging technologies have been developed at laboratory or pilot plant scale (see Table 1). With regard to RO concentrates from WWTP, the manuscript addresses recent studies that are mainly focused on reducing the organic pollutant load through the application of innovative advanced oxidation technologies. Finally, works that report the treatment of RO concentrates from industrial sources are analyzed as well.

  16. Majorana bound states in two-channel time-reversal-symmetric nanowire systems.

    Science.gov (United States)

    Gaidamauskas, Erikas; Paaske, Jens; Flensberg, Karsten

    2014-03-28

    We consider time-reversal-symmetric two-channel semiconducting quantum wires proximity coupled to a conventional s-wave superconductor. We analyze the requirements for a nontrivial topological phase and find that the necessary conditions are (1) the determinant of the pairing matrix in channel space must be negative, (2) inversion symmetry must be broken, and (3) the two channels must have different spin-orbit couplings. The first condition can be implemented in semiconducting nanowire systems where interactions suppress intra-channel pairing, while the inversion symmetry can be broken by tuning the chemical potentials of the channels. For the case of collinear spin-orbit directions, we find a general expression for the topological invariant by block diagonalization into two blocks with chiral symmetry only. By projection to the low-energy sector, we solve for the zero modes explicitly and study the details of the gap closing, which in the general case happens at finite momenta.

  17. The upregulation of pro-inflammatory cytokines in the rabbit uterus under the lipopolysaccaride-induced reversible immunoresponse state.

    Science.gov (United States)

    Liu, S J; Shi, Y; Liu, C; Zhang, M; Zuo, Z C; Zeng, C J; Zhou, G B; Xian, H; Song, T Z

    2017-01-01

    The reproductive organs are more likely to develop gram-negative bacterial infection than other internal organs because of direct access to the body surface. The objective of this study was (1) to provide a suitable intravenous injection dose of lipopolysaccharides (LPS) instead of gram-negative bacterial infection in order to induce a reversible immunoresponse state and (2) to examine the expression levels of pro-inflammatory cytokines in the uterus of rabbits while in an immunoresponse state. Two series of experiments were performed to accomplish these objectives. In the first series, 20 healthy New Zealand White female rabbits were divided into 5 homogeneous groups (n=4), and intravenously injected with 0, 0.5, 1, 2, or 4mg/kg body weight (BW) of LPS derived from Escherichia coli dissolved in 2ml of sterile saline (LPS carrier). The control group received only saline. The concentrations of IL-1β, IL-6, and TNF-α in serum and the white blood cell count changed with time after LPS stimulation, and certain doses of LPS led to the death of some rabbits. The results suggested that a dose of 0.5mg/kg of LPS induced a reversible immunoresponse state. In the second series, 4 rabbits were not injected (0h), 16 rabbits were injected with 0.5mg/kg LPS, and 16 rabbits in the control group were injected with 2ml of sterile saline. Tissues of the uterine horn, uterine body, and cervix from the 36 rabbits were collected at 0, 1.5, 3, 6, and 12h (n=4) postinjection for examination of the expression levels of IL-1β, IL-6, and TNF-α by quantitative real-time PCR (qRT-PCR). The results suggested that 0.5mg/kg of LPS upregulated the expression levels of IL-1β, IL-6 and TNF-α in the uterine body and uterine horn, and IL-6 in the cervix. In conclusion, the expression levels of IL-1β, IL-6 and TNF-α were upregulated in the uterus of rabbits under the reversible immunoresponse state induced by 0.5mg/kg of LPS-injection.

  18. The neutron star soft X-ray transient 1H 1905+000 in quiescence

    NARCIS (Netherlands)

    Jonker, P.G.; Bassa, C.G.; Nelemans, G.; Juett, A.M.; Brown, E.F.; Chakrabarty, D.

    2006-01-01

    In this paper, we report on our analysis of a ~25ks. Chandra X-ray observation of the neutron star soft X-ray transient (SXT) 1H 1905+000 in quiescence. Furthermore, we discuss our findings of the analysis of optical photometric observations which we obtained using the Magellan telescope and photome

  19. X-ray and optical studies of SAX J1808.4-3658 in quiescence

    NARCIS (Netherlands)

    C.O. Heinke; C.J. Deloye; P.G. Jonker; R. Wijnands; R.E. Taam

    2008-01-01

    We have observed the accreting millisecond X-ray pulsar SAX J1808.4-3658 (1808) in quiescence during two 50 ksec XMM-Newton observations, and acquired near-simultaneous photometry with Gemini South. We find 1808's X-ray spectrum to be hard, describable with an absorbed power-law of photon index 1.7-

  20. The return to quiescence of Aql X-1 following the 2010 outburst

    NARCIS (Netherlands)

    Campana, S.; Brivio, F.; Degenaar, N.; Mereghetti, S.; Wijnands, R.; D'Avanzo, P.; Israel, G.L.; Stella, L.

    2014-01-01

    Aql X-1 is the most prolific low-mass X-ray binary transient hosting a neutron star. In this paper we focus on the return to quiescence following the 2010 outburst of the source. This decay was monitored thanks to 11 pointed observations taken with XMM-Newton, Chandra and Swift. The decay from

  1. Pericytes in the myovascular niche promote post-natal myofiber growth and satellite cell quiescence.

    Science.gov (United States)

    Kostallari, Enis; Baba-Amer, Yasmine; Alonso-Martin, Sonia; Ngoh, Pamela; Relaix, Frederic; Lafuste, Peggy; Gherardi, Romain K

    2015-04-01

    The satellite cells, which serve as adult muscle stem cells, are both located beneath myofiber basement membranes and closely associated with capillary endothelial cells. We observed that 90% of capillaries were associated with pericytes in adult mouse and human muscle. During post-natal growth, newly formed vessels with their neuroglial 2 proteoglycan (NG2)-positive pericytes became progressively associated with the post-natal muscle stem cells, as myofibers increased in size and satellite cells entered into quiescence. In vitro, human muscle-derived pericytes promoted myogenic cell differentiation through insulin-like growth factor 1 (IGF1) and myogenic cell quiescence through angiopoietin 1 (ANGPT1). Diphtheria toxin-induced ablation of muscle pericytes in growing mice led both to myofiber hypotrophy and to impaired establishment of stem cells quiescence. Similar effects were observed following conditional in vivo deletion of pericyte Igf1 and Angpt1 genes, respectively. Our data therefore demonstrate that, by promoting post-natal myogenesis and stem cell quiescence, pericytes play a key role in the microvascular niche of satellite cells. © 2015. Published by The Company of Biologists Ltd.

  2. Searching for High-energy, Horizon-scale Emissions from Galactic Black Hole Transients during Quiescence

    Science.gov (United States)

    Lin, L. C.-C.; Pu, Hung-Yi; Hirotani, Kouichi; Kong, Albert K. H.; Matsushita, Satoki; Chang, Hsiang-Kuang; Inoue, Makoto; Tam, Pak-Hin T.

    2017-08-01

    We search for the gamma-ray counterparts of stellar-mass black holes using the long-term Fermi archive to investigate the electrostatic acceleration of electrons and positrons in the vicinity of the event horizon. We achieve this by applying the pulsar outer-gap model to their magnetospheres. When a black hole transient (BHT) is in a low-hard or quiescent state, the radiatively inefficient accretion flow cannot emit enough MeV photons that are required to sustain the force-free magnetosphere in the polar funnel via two-photon collisions. In this charge-starved gap region, an electric field arises along the magnetic field lines to accelerate electrons and positrons into ultra-relativistic energies. These relativistic leptons emit copious Gamma-rays via the curvature and inverse-Compton (IC) processes. It is found that these gamma-ray emissions exhibit a flaring activity when the plasma accretion rate typically stays between 0.01% and 0.005% of the Eddington value for rapidly rotating, stellar-mass black holes. By analyzing the detection limit determined from archival Fermi/Large Area Telescope data, we find that the 7-year averaged duty cycle of such flaring activities should be less than 5% and 10% for XTE J1118+480 and 1A 0620-00, respectively, and that the detection limit is comparable to the theoretical prediction for V404 Cyg. It is predicted that the gap emission can be discriminated from the jet emission if we investigate the high-energy spectral behavior or observe nearby BHTs during deep quiescence simultaneously in infrared wavelength and very-high energies.

  3. Pseudo-time-reversal symmetry and topological edge states in two-dimensional acoustic crystals

    KAUST Repository

    Mei, Jun

    2016-09-02

    We propose a simple two-dimensional acoustic crystal to realize topologically protected edge states for acoustic waves. The acoustic crystal is composed of a triangular array of core-shell cylinders embedded in a water host. By utilizing the point group symmetry of two doubly degenerate eigenstates at the Î

  4. High Reversibility of Soft Electrode Materials in All-solid-state Batteries

    Directory of Open Access Journals (Sweden)

    Atsushi eSakuda

    2016-05-01

    Full Text Available All-solid-state batteries using inorganic solid electrolytes (SEs are considered to be ideal batteries for electric vehicles (EVs and plug-in hybrid electric vehicles (PHEVs because they are potentially safer than conventional lithium-ion batteries (LIBs. In addition, all-solid-state batteries are expected to have long battery lives owing to the inhibition of chemical side reactions because only lithium ions move through the typically used inorganic SEs. The development of high-energy (more than 300 Wh kg-1 secondary batteries has been eagerly anticipated for years. The application of high-capacity electrode active materials is essential for fabricating such batteries. Recently, we proposed metal polysulfides as new electrode materials. These materials show higher conductivity and density than sulfur, which is advantageous for fabricating batteries with relatively higher energy density. Lithium niobium sulfides, such as Li3NbS4, have relatively high density, conductivity, and rate capability among metal polysulfide materials, and batteries with these materials have capacities high enough to potentially exceed the gravimetric energy density of conventional LIBs.Favorable solid-solid contact between the electrode and electrolyte particles is a key factor for fabricating high performance all-solid-state batteries. Conventional oxide-based positive electrode materials tend to be given rise to cracks during fabrication and/or charge-discharge processes. Here we report all-solid-state cells using lithium niobium sulfide as a positive electrode material, where favorable solid-solid contact was established by using lithium sulfide electrode materials because of their high processability. Cracks were barely observed in the electrode particles in the all-solid-state cells before or after charging and discharging with a high capacity of approx. 400 mAh g-1, suggesting that the lithium niobium sulfide electrode charged and discharged without experiencing

  5. Transgenic expression of BRCA1 disturbs hematopoietic stem and progenitor cells quiescence and function

    Energy Technology Data Exchange (ETDEWEB)

    Bai, Lin; Shi, Guiying; Zhang, Xu; Dong, Wei; Zhang, Lianfeng, E-mail: zhanglf@cnilas.org

    2013-10-15

    The balance between quiescence and proliferation of HSCs is an important regulator of hematopoiesis. Loss of quiescence frequently results in HSCs exhaustion, which underscores the importance of tight regulation of proliferation in these cells. Studies have indicated that cyclin-dependent kinases are involved in the regulation of quiescence in HSCs. BRCA1 plays an important role in the repair of DNA double-stranded breaks, cell cycle, apoptosis and transcription. BRCA1 is expressed in the bone marrow. However, the function of BRCA1 in HSCs is unknown. In our study, we generated BRCA1 transgenic mice to investigate the effects of BRCA1 on the mechanisms of quiescence and differentiation in HSCs. The results demonstrate that over-expression of BRCA1 in the bone marrow impairs the development of B lymphocytes. Furthermore, BRCA1 induced an increase in the number of LSKs, LT-HSCs, ST-HSCs and MPPs. A competitive transplantation assay found that BRCA1 transgenic mice failed to reconstitute hematopoiesis. Moreover, BRCA1 regulates the expression of p21{sup waf1}/cip1 and p57{sup kip2}, which results in a loss of quiescence in LSKs. Together, over-expression of BRCA1 in bone marrow disrupted the quiescent of LSKs, induced excessive accumulation of LSKs, and disrupted differentiation of the HSCs, which acts through the down-regulated of p21{sup waf1}/cip1 and p57{sup kip2}. - Highlights: • Over-expression of BRCA1 results in impaired B lymphocyte development. • BRCA1 transgenic mice disrupted the quiescent of LSKs, induced excessive accumulation of LSKs. • BRCA1 impairs the function of HSCs through the down-regulated of p21{sup waf1/cip1} and p57{sup kip2}.

  6. Simplification of reversible Markov chains by removal of states with low equilibrium occupancy.

    Science.gov (United States)

    Ullah, Ghanim; Bruno, William J; Pearson, John E

    2012-10-21

    We present a practical method for simplifying Markov chains on a potentially large state space when detailed balance holds. A simple and transparent technique is introduced to remove states with low equilibrium occupancy. The resulting system has fewer parameters. The resulting effective rates between the remaining nodes give dynamics identical to the original system's except on very fast timescales. This procedure amounts to using separation of timescales to neglect small capacitance nodes in a network of resistors and capacitors. We illustrate the technique by simplifying various reaction networks, including transforming an acyclic four-node network to a three-node cyclic network. For a reaction step in which a ligand binds, the law of mass action implies a forward rate proportional to ligand concentration. The effective rates in the simplified network are found to be rational functions of ligand concentration.

  7. Theoretical and Methodological Foundations of Reverse Inclusion: The Experience of Moscow State University of Humanities and Economics

    Directory of Open Access Journals (Sweden)

    Bairamov V.D.,

    2017-08-01

    Full Text Available The article substantiates the model of “reverse inclusion” in the interconnection of sociostructural, sociocultural and spatial aspects. In addition to these aspects, the paper describes the socio-legal and socio-pedagogical foundations of the model. Along with the key category of inclusion the following categories are revealed: “disability”, “disabled person”, “social barrier”, “inclusive social strategy”, and “inclusive strategy in education”. “Reverse inclusion” is opposed to the dominant model of direct inclusion. Due to the fact that the article is of a theoretical and methodological nature, factual data play an illustrative role. The empirical base is represented by secondary data, as well as by some references to the authors’ research of 2016 conducted by the staff of the research laboratory of the Moscow State University of Humanities and Economics for purposes of vocational guidance; in this research a series of 27 in-depth interviews were carried out with students with musculoskeletal disorders studying at MSUHE.

  8. Enhancing the quantum state transfer between two atoms in separate cavities via weak measurement and its reversal

    Science.gov (United States)

    Li, Yan-Ling; Huang, Jinsong; Xu, Zhonghui; Xiao, Xing

    2017-10-01

    Taking the advantage of weak measurement and quantum measurement reversal, we propose a scheme to enhance the fidelity of transferring quantum state from one atom trapped in cavity to another distant one trapped in another cavity which is coupled by an optical fiber. It is turned out that the fidelity can be greatly improved even when the system is under serious dissipation. Moreover, the scheme works in both the strong-coupling and weak-coupling regimes. It is also robust to the ratio of the coupling constant between the atoms and the cavity modes to the coupling constant between the fiber and cavity modes. The underlying mechanism can be attributed to the probabilistic nature of weak measurements.

  9. Excited state intramolecular charge transfer reaction in non-aqueous reverse micelles: Effects of solvent confinement and electrolyte concentration

    Indian Academy of Sciences (India)

    Tuhin Pradhan; Harun Al Rasid Gazi; Biswajit Guchhait; Ranjit Biswas

    2012-03-01

    Steady state and time resolved fluorescence emission spectroscopy have been employed to investigate the effects of solvent confinement and electrolyte concentration on excited state intramolecular charge transfer (ICT) reaction in 4-(1-pyrrolidinyl) benzonitrile (P5C), 4-(1-piperidinyl) benzonitrile (P6C), and 4-(1-morpholenyl) benzonitrile (M6C) in AOT/n-heptane/acetonitrile and AOT/n-heptane/methanol reverse micelles. Dramatic confinement effects have been revealed via a huge reduction (factor ranging between 100 and 20) over bulk values of both equilibrium and reaction rate constants. A strong dependence on the size of the confinement () of these quantities has also been observed. dependent average static dielectric constant, viscosity and solvation time-scale have been determined. Estimated dielectric constants for confined methanol and acetonitrile show a decrease from the respective bulk values by a factor of 3-5 and viscosities increased by a factor of 2 at the highest considered. Addition of electrolyte at = 5 for acetonitrile is found to produce a linear increase of confined solvent viscosity but leads to a non-monotonic electrolyte concentration dependence of average solvation time. Reaction rate constant is found to decrease linearly with electrolyte concentration for P5C and P6C but non-monotonically for M6C, the highest decrease for all the molecules being ∼ 20% over the value in the absence of added electrolyte in the solvent pool. The observed huge reduction in reaction rate constant is attributed to the effects of decreased solution polarity, enhanced viscosity and slowed-down solvent reorganization of the solvent under confinement in these non-aqueous reverse micelles.

  10. Observation of Quantum Spin Hall States in InAs/GaSb Bilayers under Broken Time-Reversal Symmetry

    Science.gov (United States)

    Du, Lingjie; Knez, Ivan; Sullivan, Gerard; Du, Rui-Rui

    2014-03-01

    Topological insulators (TIs) are a novel class of materials with nontrivial surface or edge states. Time-reversal symmetry (TRS) protected TIs are characterized by the Z2 topological invariant. The fate of the Z2 TIs under broken TRS is a fundamental question in understanding the physics of topological matter but remains largely unanswered. Here we show, a two-dimensional TI is realized in an inverted electron-hole bilayer engineered from InAs/GaSb semiconductors which retains robust helical liquid (HL) edge states under a strong magnetic field. Wide conductance plateaus of 2e2/h value are observed; they persist to 10T applied in-plane field before transitioning to a trivial semimetal. In a perpendicular field up to 35T, broken TRS leads to a spatial separation of the movers in Kramers pair and consequently the intra-pair backscattering phase space vanishes, i.e., the conductance increases from 2e2/h in strong fields manifesting chiral edge transport. We propose a phenomenological phases diagram, where inside the topological gap the HL transfers into a ``canned helical state'' driven by perpendicular fields. Our findings suggest that once established, the HL is remarkably resilient and only undergoes adiabatic deformation under TRS breaking. The work at Rice was supported by DOE, NSF, and Welch Foundation.

  11. Application of Implementation Science Methodology to Immediate Postpartum Long-Acting Reversible Contraception Policy Roll-Out Across States.

    Science.gov (United States)

    Rankin, Kristin M; Kroelinger, Charlan D; DeSisto, Carla L; Pliska, Ellen; Akbarali, Sanaa; Mackie, Christine N; Goodman, David A

    2016-11-01

    Purpose Providing long-acting reversible contraception (LARC) in the immediate postpartum period is an evidence-based strategy for expanding women's access to highly effective contraception and for reducing unintended and rapid repeat pregnancy. The purpose of this article is to demonstrate the application of implementation science methodology to study the complexities of rolling-out policies that promote immediate postpartum LARC use across states. Description The Immediate Postpartum LARC Learning Community, sponsored by the Association of State and Territorial Health Officials (ASTHO), is made up of multi-disciplinary, multi-agency teams from 13 early-adopting states with Medicaid reimbursement policies promoting immediate postpartum LARC. Partners include federal agencies and maternal and child health organizations. The Learning Community discussed barriers, opportunities, strategies, and promising practices at an in-person meeting. Implementation science theory and methods, including the Consolidated Framework for Implementation Research (CFIR), and a recent compilation of implementation strategies, provide useful tools for studying the complexities of implementing immediate postpartum LARC policies in birthing facilities across early adopting states. Assessment To demonstrate the utility of this framework for guiding the expansion of immediate postpartum LARC policies, illustrative examples of barriers and strategies discussed during the in-person ASTHO Learning Community meeting are organized by the five CFIR domains-intervention characteristics, outer setting, inner setting, characteristics of the individuals involved, and process. Conclusion States considering adopting policies can learn from ASTHO's Immediate Postpartum LARC Learning Community. Applying implementation science principles may lead to more effective statewide scale-up of immediate postpartum LARC and other evidence-based strategies to improve women and children's health.

  12. Solid-state non-volatile electronically programmable reversible variable resistance device

    Science.gov (United States)

    Ramesham, Rajeshuni (Inventor); Thakoor, Sarita (Inventor); Daud, Taher (Inventor); Thakoor, Aniklumar P. (Inventor)

    1989-01-01

    A solid-state variable resistance device (10) whose resistance can be repeatedly altered by a control signal over a wide range, and which will remain stable after the signal is removed, is formed on an insulated layer (14), supported on a substrate (12) and comprises a set of electrodes (16a, 16b) connected by a layer (18) of material, which changes from an insulator to a conductor upon the injection of ions, covered by a layer (22) of material with insulating properties which permit the passage of ions, overlaid by an ion donor material (20). The ion donor material is overlaid by an insulating layer (24) upon which is deposited a control gate (26) located above the contacts. In a preferred embodiment, the variable resistance material comprises WO.sub.3, the ion donor layer comprises Cr.sub.2 O.sub.3, and the layers sandwiching the ion donor layer comprise silicon monoxide. When a voltage is applied to the gate, the resistance between the electrode contacts changes, decreasing with positive voltage and increasing with negative voltage.

  13. Reovirus type 3 synthesizes proteins in interferon-treated HeLa cells without reversing the antiviral state.

    Science.gov (United States)

    Feduchi, E; Esteban, M; Carrasco, L

    1988-06-01

    Treatment of HeLa cells with human lymphoblastoid interferon (IFN-alpha) does not inhibit reovirus type 3 protein synthesis during virus infection. In contrast, reovirus translation is blocked by treatment of L cells with mouse IFN-alpha. The (2'-5')A synthetase activity is induced in HeLa cells by IFN-alpha treatment and is activated after reovirus infection, since cell lysates from these cells synthesize in vitro (2'-5')A oligonucleotides. The IFN-induced protein kinase activity is also triggered in those lysates upon dsRNA addition. Thus, contrary to DNA-containing viruses, such as vaccinia virus or adenovirus, reovirus infection does not destroy or reverse the IFN-induced antiviral state. In support of this conclusion, superinfection with poliovirus or vesicular stomatitis virus of reovirus-infected HeLa cells treated with IFN leads only to a blockade of translation of the former viruses. These results provide a remarkable example where in the same cells doubly infected with two different viruses, the antiviral state induced by IFN-alpha is manifested by selectively inhibiting translation of one kind of virus (poliovirus or vesicular stomatitis virus) without affecting the translation of reovirus type 3. In addition, these results indicate that the resistance of reovirus translation to inhibition by IFN is different from the mechanism of resistance induced by DNA-containing viruses.

  14. Analysis of a Wave-Powered, Reverse-Osmosis System and Its Economic Availability in the United States: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Yu, Yi-Hsiang [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Jenne, Dale S [National Renewable Energy Laboratory (NREL), Golden, CO (United States)

    2017-08-09

    A wave energy converter (WEC) system has the potential to convert the wave energy resource directly into the high-pressure flow that is needed by the desalination system to permeate saltwater through the reverse-osmosis membrane to generate clean water. In this study, a wave-to-water numerical model was developed to investigate the potential use of a wave-powered desalination system (WPDS) for water production in the United States. The model was developed by coupling a time-domain radiation-and-diffraction-method-based numerical tool (WEC-Sim) for predicting the hydrodynamic performance of WECs with a solution-diffusion model that was used to simulate the reverse-osmosis process. To evaluate the feasibility of the WPDS, the wave-to-water numerical model was applied to simulate a desalination system that used an oscillating surge WEC device to pump seawater through the system. The annual water production was estimated based on the wave resource at a reference site on the coast of northern California to investigate the potential cost of water in that area, where the cost of water and electricity is high compared to other regions. In the scenario evaluated, for a 100-unit utility-scale electricity-producing array, the estimated levelized cost of energy for these WECs is about 3-6 times the U.S.'s current, unsubsidized electricity rates. However, with clean water as an end product and by directly producing pressurized water with WECs, rather than electricity as an intermediary, it is presently only 12 percent greater than typical water cost in California. This study suggests that a WEC array that produces water may be a viable, near-term solution to the nation's water supply, and the niche application of the WPDS may also provide developers with new opportunities to further develop technologies that benefit both the electric and drinking water markets.

  15. Quantitative mapping of precursory seismic quiescence before the 1989, M 7.1off-Sanriku earthquake, Japan

    Directory of Open Access Journals (Sweden)

    N. Umino

    1999-06-01

    Full Text Available The first main shock of the off-Sanriku earthquake sequence (02/11/89, M 7.1; 18/07/92, M 6.9; 28/12/94, M 7.5 was preceded by a precursory seismic quiescence lasting 2.5 ± 1 year and up to this main shock. The detailed properties of this quiescence were mapped as a function of time and space by a gridding technique using the ZMAP computer code, and the statistical significance was estimated by generating a synthetic catalog based on the microearthquake catalog of Tohoku University, which was the data set used. The statistically most significant expression of this precursory quiescence has a probability of 0.1% to have occurred at random and was located in the eastern part of the 1989 aftershock area, at a point to which the 1994 aftershocks extended also. If we define the dimensions of the quiescence anomaly by a vertical cylinder with the depth of the entire seismogenic layer, centered at the point of most significant quiescence and showing a rate decrease of 75%, then we find its radius is 25 ± 9 km. If we allow other shapes, such as the simplified aftershock volume of 1989, or other simple geometric figures, to define the rate decrease we find dimensions of 80 by 80 km. The characteristics of the quiescence anomaly do not depend strongly on the choice of free parameters within the following ranges: 100 ? number of events ? 400, 2.0 ? Mmin £ 3.0, 1 ? time window ? 3 years. With our method, a thorough analysis of the period before the 1994 main shock is not possible because of the interference of the extended aftershock sequence of 1989. Nevertheless, we identified a quiescence of nearly zero earthquakes located near the center of the 1994 aftershock area that lasted for one year up to that main shock. However, this quiescence period ranked only 46th in significance, behind other quiescences of equal duration and similar dimensions distributed in time and space through the data set. Because of the ubiquitous existence of periods of near

  16. Quiescence correlates strongly with directly-measured black hole mass in central galaxies

    CERN Document Server

    Terrazas, Bryan A; Henriques, Bruno M B; White, Simon D M; Cattaneo, Andrea; Woo, Joanna

    2016-01-01

    Roughly half of all stars reside in galaxies without significant ongoing star formation. However, galaxy formation models indicate that it is energetically challenging to suppress the cooling of gas and the formation of stars in galaxies that lie at the centers of their dark matter halos. In this Letter, we show that the dependence of quiescence on black hole and stellar mass is a powerful discriminant between differing models for the mechanisms that suppress star formation. Using observations of 91 star-forming and quiescent central galaxies with directly-measured black hole masses, we find that quiescent galaxies host more massive black holes than star-forming galaxies with similar stellar masses. This observational result is in qualitative agreement with models that assume that effective, more-or-less continuous AGN feedback suppresses star formation, strongly suggesting the importance of the black hole in producing quiescence in central galaxies.

  17. Quiescence Correlates Strongly with Directly Measured Black Hole Mass in Central Galaxies

    Science.gov (United States)

    Terrazas, Bryan A.; Bell, Eric F.; Henriques, Bruno M. B.; White, Simon D. M.; Cattaneo, Andrea; Woo, Joanna

    2016-10-01

    Roughly half of all stars reside in galaxies without significant ongoing star formation. However, galaxy formation models indicate that it is energetically challenging to suppress the cooling of gas and the formation of stars in galaxies that lie at the centers of their dark matter halos. In this Letter, we show that the dependence of quiescence on black hole and stellar mass is a powerful discriminant between differing models for the mechanisms that suppress star formation. Using observations of 91 star-forming and quiescent central galaxies with directly measured black hole masses, we find that quiescent galaxies host more massive black holes than star-forming galaxies with similar stellar masses. This observational result is in qualitative agreement with models that assume that effective, more-or-less continuous active galactic nucleus feedback suppresses star formation, strongly suggesting the importance of the black hole in producing quiescence in central galaxies.

  18. Seismic quiescence and b-value decrease before large events in forest-fire model

    CERN Document Server

    Mitsudo, Tetsuya; Kato, Naoyuki

    2015-01-01

    Forest fire models may be interpreted as a simple model for earthquake occurrence by translating trees and fire into stressed segments of a fault and their rupture, respectively. Here we adopt a twodimensional forest-fire model in continuous time, and focus on the temporal changes of seismicity and the b-value. We find the b-value change and seismic quiescence prior to large earthquakes by stacking many sequences towards large earthquakes. As the magnitude-frequency relation in this model is directly related to the cluster-size distribution, decrease of the b-value can be explained in terms of the change in the cluster-size distribution. Decrease of the b-value means that small clusters of stressed sites aggregate into a larger cluster. Seismic quiescence may be attributed to the decrease of stressed sites that do not belong to percolated clusters.

  19. The neutron star transient SAX J1810.8-2609 going back to quiescence

    NARCIS (Netherlands)

    Linares, M.; Degenaar, N.D.; Wijnands, R.

    2007-01-01

    We observed the neutron star transient SAX J1810.8-2609 with Swift-XRT on November 3rd and 5th, in order to follow its way to quiescence. The source was not detected during the individual ~1.6 ksec and ~1.9 ksec observations. We place 95% upper limits on its 0.5-10 keV unabsorbed fl

  20. Hypusine formation in eukaryotic initiation factor 4D is not reversed when rates or specificity of protein synthesis is altered.

    Science.gov (United States)

    Gordon, E D; Mora, R; Meredith, S C; Lindquist, S L

    1987-12-05

    In mammalian cells, a single major cellular protein (eukaryotic initiation factor 4D) is post-translationally modified by the conversion of a lysine residue into the unusual amino acid hypusine. This modification was reported to occur during mitogen-stimulated growth of lymphocytes but not during quiescence, suggesting that alternative forms of eukaryotic initiation factor 4D might play a role in the regulation of cell growth perhaps through the control of protein synthesis itself (Cooper, H. L., Park, M. H., and Folk, J. E. (1982) Cell 29, 791-797). We took advantage of the drastic changes in translational specificity which occur in heat-shocked cells of Drosophila melanogaster, and of the wide variations in translation rates which occur in response to alterations of growth media in the fungus Saccharomyces cerevisiae, to investigate the relationship between the intracellular level and state of modification of the hypusine-containing protein and the rate and specificity of translation. We also studied whether the hypusine residue in this protein might be subject to further modification or reversion to lysine. Under all conditions examined, the protein was remarkably long-lived. Furthermore, the hypusine persists in this protein as hypusine, without further modification or reversion to lysine. Thus, we observe no correlation between the state of cellular translation and the persistence or reversal of this protein's modification. In addition, the data imply that neither are the state of such key cellular processes as DNA replication, RNA transcription, or carbohydrate metabolism so correlated.

  1. A long-lasting quiescence phase of the eruptive variable V1118 Ori

    CERN Document Server

    Lorenzetti, D; Giannini, T; Harutyunyan, A; Arkharov, A A; Larionov, V M; Cusano, F; Di Paola, A; Causi, G Li; Nisini, B; Speziali, R; Vitali, F

    2015-01-01

    V1118 Ori is an eruptive variable belonging to the EXor class of Pre-Main Sequence stars whose episodic outbursts are attributed to disk accretion events. Since 2006, V1118 Ori is in the longest quiescence stage ever observed between two subsequent outbursts of its recent history. We present near-infrared photometry of V1118 Ori carried out during the last eight years, along with a complete spectroscopic coverage from 0.35 to 2.5 um. A longterm sampling of V1118 Ori in quiescence has never been done, hence we can benefit from the current circumstance to determine the lowest values (i.e. the zeroes) of the parameters to be used as a reference for evaluating the physical changes typical of more active phases. A quiescence mass accretion rate between 1--3 $\\times$ 10$^{-9}$ M$_{\\sun}$ yr$^{-1}$ can be derived and the difference with previous determinations is discussed. From line emission and IR colors analysis a visual extinction of 1-2 mag is consistently derived, confirming that V1118 Ori (at least in quiesce...

  2. XMM-Newton observations of 1A 0535+262 in quiescence.

    Directory of Open Access Journals (Sweden)

    Doroshenko V.

    2014-01-01

    Full Text Available Accretion onto magnetized neutron stars is expected to be centrifugally inhibited at low accretion rates. Several sources including 1A 0535+262, however, are known to pulsate in quiescence at luminosities below the theoretical limit predicted for the onset of the centrifugal barrier. Here we present the results of an analysis of a ~ 50 ks long XMM-Newton observation of 1A 0535+262 in quiescence. At the time of the observation, the neutron star was close to the apastron, and the source had remained quiet for two orbital cycles. In spite of this, we detected a pulsed X-ray flux of ~ 3×10−11erg cm−2 s−1. Several observed properties, including the power spectrum, remained similar to those observed in the outbursts. Particularly, we have found that the frequency of the break detected in the quiescent noise power spectrum follows the same correlation with flux observed when the source is in outburst. We argue that, along with other arguments previously reported in the literature, our results suggest that the accretion in quiescence also proceeds from an accretion disk around the neutron star.

  3. Distinct histone methylation and transcription profiles are established during the development of cellular quiescence in yeast.

    Science.gov (United States)

    Young, Conor P; Hillyer, Cory; Hokamp, Karsten; Fitzpatrick, Darren J; Konstantinov, Nikifor K; Welty, Jacqueline S; Ness, Scott A; Werner-Washburne, Margaret; Fleming, Alastair B; Osley, Mary Ann

    2017-01-26

    Quiescent cells have a low level of gene activity compared to growing cells. Using a yeast model for cellular quiescence, we defined the genome-wide profiles of three species of histone methylation associated with active transcription between growing and quiescent cells, and correlated these profiles with the presence of RNA polymerase II and transcripts. Quiescent cells retained histone methylations normally associated with transcriptionally active chromatin and had many transcripts in common with growing cells. Quiescent cells also contained significant levels of RNA polymerase II, but only low levels of the canonical initiating and elongating forms of the polymerase. The RNA polymerase II associated with genes in quiescent cells displayed a distinct occupancy profile compared to its pattern of occupancy across genes in actively growing cells. Although transcription is generally repressed in quiescent cells, analysis of individual genes identified a period of active transcription during the development of quiescence. The data suggest that the transcript profile and histone methylation marks in quiescent cells were established both in growing cells and during the development of quiescence and then retained in these cells. Together, this might ensure that quiescent cells can rapidly adapt to a changing environment to resume growth.

  4. THE X-RAY PROPERTIES OF THE BLACK HOLE TRANSIENT MAXI J1659-152 IN QUIESCENCE

    Energy Technology Data Exchange (ETDEWEB)

    Homan, Jeroen [Kavli Institute for Astrophysics and Space Research, Massachusetts Institute of Technology, 70 Vassar Street, Cambridge, MA 02139 (United States); Fridriksson, Joel K.; Altamirano, Diego [Astronomical Institute ' ' Anton Pannekoek' ' , University of Amsterdam, Postbus 94249, 1090 GE Amsterdam (Netherlands); Jonker, Peter G. [SRON, Netherlands Institute for Space Research, Sorbonnelaan 2, 3584 CA Utrecht (Netherlands); Russell, David M. [Instituto de Astrofisica de Canarias (IAC), E-38200 La Laguna, Tenerife (Spain); Gallo, Elena [Department of Astronomy, University of Michigan, 500 Church Street, Ann Arbor, MI 48109 (United States); Kuulkers, Erik [European Space Astronomy Centre (ESA/ESAC), Science Operations Department, E-28691 Villanueva de la Canada (Madrid) (Spain); Rea, Nanda, E-mail: jeroen@space.mit.edu [Institute of Space Sciences (CSIC-IEEC), Campus UAB, Faculty of Science, Torre C5-parell, E-08193 Barcelona (Spain)

    2013-09-20

    We present new Chandra X-ray observations of the transient black hole X-ray binary MAXI J1659-152 in quiescence. These observations were made more than one year after the end of the source's 2010-2011 outburst. We detect the source at a 0.5-10 keV flux of 2.8(8) Multiplication-Sign 10{sup -15} erg s{sup -1} cm{sup -2}, which corresponds to a luminosity of {approx}1.2 Multiplication-Sign 10{sup 31} (d/6 kpc){sup 2} erg s{sup -1}. This level, while being the lowest at which the source has been detected, is within factors of {approx}2 of the levels seen at the end of the initial decay of the outburst and soon after a major reflare of the source. The quiescent luminosity of MAXI J1659-152, which is the shortest-orbital-period black hole X-ray binary ({approx}2.4 hr), is lower than that of neutron-star X-ray binaries with similar periods. However, it is higher than the quiescent luminosities found for black hole X-ray binaries with orbital periods {approx}2-4 times longer. This could imply that a minimum quiescent luminosity may exist for black hole X-ray binaries, around orbital periods of {approx}5-10 hr, as predicted by binary-evolution models for the mass transfer rate. Compared to the hard state, we see a clear softening of the power-law spectrum in quiescence, from an index of 1.55(4) to an index of 2.5(4). We constrain the luminosity range in which this softening starts to (0.18-6.2) Multiplication-Sign 10{sup -5} (d/6 kpc){sup 2} (M/8 M{sub Sun }) L{sub Edd}, which is consistent with the ranges inferred for other sources.

  5. On the Optical -- X-ray correlation from outburst to quiescence in Low Mass X-ray Binaries: the representative cases of V404 Cyg and Cen X-4

    CERN Document Server

    Bernardini, F; Koljonen, K I I; Stella, L; Hynes, R I; Corbel, S

    2016-01-01

    Low mass X-ray binaries (LMXBs) show evidence of a global correlation of debated origin between X-ray and optical luminosity. We study for the first time this correlation in two transient LMXBs, the black hole V404 Cyg and the neutron star Cen X-4, over 6 orders of magnitude in X-ray luminosity, from outburst to quiescence. After subtracting the contribution from the companion star, the Cen X-4 data can be described by a single power law correlation of the form $L_{opt}\\propto\\,L_{X}^{0.44}$, consistent with disk reprocessing. We find a similar correlation slope for V404 Cyg in quiescence (0.46) and a steeper one (0.56) in the outburst hard state of 1989. However, V404 Cyg is about $160-280$ times optically brighter, at a given $3-9$ keV X-ray luminosity, compared to Cen X-4. This ratio is a factor of 10 smaller in quiescence, where the normalization of the V404 Cyg correlation also changes. We show that once the bolometric X-ray emission is considered and the known main differences between V404 Cyg and Cen X...

  6. VLT spectroscopy of XTE J2123-058 during quiescence

    CERN Document Server

    Casares, J; Shahbaz, T; Zurita, C; Charles, P A

    2001-01-01

    We present VLT low resolution spectroscopy of the neutron star X-ray transient XTE J2123-058 during its quiescent state. Our data reveal the presence of a K7V companion which contributes 77 % to the total flux at 6300 A and orbits the neutron star at K_2 = 287 +/- 12 km/s. Contrary to other soft X-ray transients (SXTs), the Halpha emission is almost exactly in antiphase with the velocity curve of the optical companion. Using the light-center technique we obtain K_1 = 140 +/- 27 km/s and hence q=K_1/K_2=M_2/M_1= 0.49 +/- 0.10. This, combined with a previous determination of the inclination angle (i=73 +/- 4) yields M_1 = 1.55 +/- 0.31 Msun and M_2 = 0.76 +/- 0.22 Msun. M_2 agrees well with the observed spectral type. Doppler tomography of the Halpha emission shows a non-symmetric accretion disc distribution mimicking that seen in SW Sex stars. Although we find a large systemic velocity of -110 +/- 8 km/s this value is consistent with the galactic rotation velocity at the position of J2123-058, and hence a halo...

  7. Recovery of the X-Ray Transient QX Nor (=X1608-52) in Outburst and Quiescence

    CERN Document Server

    Wachter, S

    1997-01-01

    We present optical and near-IR observations of QX Nor, the counterpart to the recurrent soft X-ray transient X1608-52, after its reappearance following the X-ray outburst in February 1996. The object has been seen only once before, during an X-ray outburst in 1977. Data from 3-5 months after the outburst show the counterpart at a mean magnitude of R=20.2 and variable on timescales of days. A comparison with identical observations in 1995 implies that the object has brightened by at least 1.8 mag in R following the X-ray outburst. We also detected QX Nor in the IR in both quiescence and outburst. A faint source is visible in the J but not the R band in May 1995. These first observations in the quiescent state yield magnitudes and colors consistent with optical emission from a low mass companion in the binary system, as is true in other soft X-ray transients.

  8. Impaired coenzyme A synthesis in fission yeast causes defective mitosis, quiescence-exit failure, histone hypoacetylation and fragile DNA.

    Science.gov (United States)

    Nakamura, Takahiro; Pluskal, Tomáš; Nakaseko, Yukinobu; Yanagida, Mitsuhiro

    2012-09-01

    Biosynthesis of coenzyme A (CoA) requires a five-step process using pantothenate and cysteine in the fission yeast Schizosaccharomyces pombe. CoA contains a thiol (SH) group, which reacts with carboxylic acid to form thioesters, giving rise to acyl-activated CoAs such as acetyl-CoA. Acetyl-CoA is essential for energy metabolism and protein acetylation, and, in higher eukaryotes, for the production of neurotransmitters. We isolated a novel S. pombe temperature-sensitive strain ppc1-537 mutated in the catalytic region of phosphopantothenoylcysteine synthetase (designated Ppc1), which is essential for CoA synthesis. The mutant becomes auxotrophic to pantothenate at permissive temperature, displaying greatly decreased levels of CoA, acetyl-CoA and histone acetylation. Moreover, ppc1-537 mutant cells failed to restore proliferation from quiescence. Ppc1 is thus the product of a super-housekeeping gene. The ppc1-537 mutant showed combined synthetic lethal defects with five of six histone deacetylase mutants, whereas sir2 deletion exceptionally rescued the ppc1-537 phenotype. In synchronous cultures, ppc1-537 cells can proceed to the S phase, but lose viability during mitosis failing in sister centromere/kinetochore segregation and nuclear division. Additionally, double-strand break repair is defective in the ppc1-537 mutant, producing fragile broken DNA, probably owing to diminished histone acetylation. The CoA-supported metabolism thus controls the state of chromosome DNA.

  9. A Chandra observation of the accretion-driven millisecond X-ray pulsar XTE J0929-314 in quiescence

    CERN Document Server

    Wijnands, R; Heinke, C O; Miller, J M; Lewin, W H G; Wijnands, Rudy; Homan, Jeroen; Heinke, Craig O.; Miller, Jon M.; Lewin, Walter H. G.

    2004-01-01

    We observed the accretion-driven millisecond X-ray pulsar XTE J0929-314 in its quiescent state using Chandra. XTE J0929-314 is the second such source to be observed in quiescence, after SAX J1808.4-3658. We detected 22 source photons (in the energy range 0.3-8 keV) in ~24.4 ksec, resulting in a background-corrected count rate of 9+/-2 x 10^{-4} counts s^{-1}. This small number of photons detected did not allow for a detailed spectral analysis of the quiescent spectrum, but we can demonstrate that the spectrum is harder than simple thermal emission which is usually presumed to arise from a cooling neutron star that has been heated during the outbursts. Assuming a power-law model for the X-ray spectrum, we obtain a power-law index of 2.2+/-0.6 and an unabsorbed X-ray flux of 6.5^{+2.8}_{-2.1} x 10^{-15} ergs s^{-1} cm^{-2} (for the energy range 0.5-10 keV), resulting in a 0.5-10 keV X-ray luminosity of 8+/-3 x 10^{31} (d/10 kpc)^2 ergs s^{-1}, with d the distance toward the source in kpc. No thermal component c...

  10. A Chandra observation of the neutron star X-ray transient and eclipsing binary MXB 1659-29 in quiescence

    CERN Document Server

    Wijnands, R; Miller, J M; Homan, J; Wachter, S; Lewin, W H G; Wijnands, Rudy; Nowak, Mike; Miller, Jon M.; Homan, Jeroen; Wachter, Stefanie; Lewin, Walter H. G.

    2003-01-01

    After almost 2.5 years of actively accreting, the neutron star X-ray transient and eclipsing binary MXB 1659-29 returned to quiescence in 2001 September. We report on a Chandra observation of this source taken a little over a month after this transition. The source was detected at an unabsorbed 0.5-10 keV flux of only (2.7 - 3.6) x 10^{-13} erg cm^-2 s^-1, which implies a 0.5-10 keV X-ray luminosity of approximately (3.2 - 4.3) x 10^{33} (d/10 kpc)^2 erg s^-1, with d is the distance to the source in kpc. Its spectrum had a thermal shape and could be well fitted by either a blackbody with a temperature kT of ~0.3 keV or with a neutron star atmosphere model with a kT of ~0.1 keV. The luminosity and spectral shape of MXB 1659-29 are very similar to those observed of the other neutron star X-ray transients when they are in their quiescent state. The source was variable during our observation, exhibiting a complete eclipse of the inner part of the system by the companion star. Dipping behavior was observed before ...

  11. Magnetic fluctuation behavior during the transition between quasi-single helicity and multi helicity states in the reversed-field pinch plasma

    Science.gov (United States)

    Yambe, Kiyoyuki; Sakakita, Hajime; Hirano, Yoichi; Koguchi, Haruhisa

    2016-11-01

    We measured the variation of magnetic and electrostatic fluctuations observed during the transition between the quasi-single helicity (QSH) and multi helicity (MH) states in the edge region of the Toroidal Pinch Experiment-Reversed eXperiment reversed-field pinch plasma [Yagi et al., Fusion Eng. Des. 45, 421 (1999)]. The high-frequency magnetic fluctuations largely decrease at the start of the QSH state. During the QSH state, the toroidal and radial magnetic fluctuations slightly increase again between 12 and 18 kHz but the decrease in the poloidal magnetic fluctuation is maintained. The confinement of fast electrons may be improved in the period of the QSH state although the radial magnetic fluctuation increases between 12 and 18 kHz. It is suggested that the improved confinement of fast electrons may be obtained by the decrease in the fast radial magnetic fluctuation having the frequency higher than 20 kHz in the period of the QSH state. Contrarily, the transition from QSH to MH states occurs with the increase in the slow toroidal magnetic fluctuation having the frequency lower than 10 kHz. The QSH state may bring a good confinement of fast electrons by the reduced high-frequency magnetic fluctuation compared with the MH state.

  12. Reverse Logistics

    OpenAIRE

    Kulikova, Olga

    2016-01-01

    This thesis was focused on the analysis of the concept of reverse logistics and actual reverse processes which are implemented in mining industry and finding solutions for the optimization of reverse logistics in this sphere. The objective of this paper was the assessment of the development of reverse logistics in mining industry on the example of potash production. The theoretical part was based on reverse logistics and mining waste related literature and provided foundations for further...

  13. Viscous evolution of accretion discs in the quiescence of dwarf novae

    Science.gov (United States)

    Mineshige, Shin; Wood, Janet H.

    1989-01-01

    Viscous evolution of accretion disks in the quiescence of dwarf novae is investigated semi-analytically. There are two key factors: the inward flow of the initial mass in the disk and the diffusion of the material added into the disk. The results are compared with the brightness temperature distributions obtained by the eclipse mapping of Z Cha and OY Car. The functional form of the viscosity parameter a, its values, the types of outbursts, and the application to soft X-ray transients are discussed.

  14. Viscous evolution of accretion discs in the quiescence of dwarf novae

    Energy Technology Data Exchange (ETDEWEB)

    Mineshige, Shin (Texas Univ., Austin, TX (USA). Dept. of Astronomy); Wood, J.H. (Texas Univ., Austin, TX (USA). Dept. of Astronomy Cambridge Univ. (UK). Inst. of Astronomy)

    1989-11-15

    Viscous evolution of accretion discs in the quiescence of dwarf novae is investigated semi-analytically. There are two key factors: the inward flow of the initial mass in the disc and the diffusion of the material added into the disc. The results are compared with the brightness temperature distributions obtained by the eclipse mapping of Z Cha and OY Car. The functional form of the viscosity parameter, its values, the types of outbursts, and the application to soft X-ray transients are discussed. (author).

  15. RS Ophiuchi in Quiescence: Why is it X-ray Faint?

    CERN Document Server

    Mukai, Koji

    2008-01-01

    The short interval between successive outbursts of RS Oph strongly suggests that it has a high mass white dwarf accreting at a high rate. This, in turn, suggests the possibility of prominent X-ray emission from RS Oph in quiescence. However, archival quiescent X-ray observations of RS Oph show it to be a modest soft X-ray source but not a strong 2-10 keV X-ray source. In this aspect, RS Oph differs markedly from T CrB. We speculate on the possible mechanisms that could significantly suppress the 2-10 keV X-ray emission in RS Oph.

  16. Runx1 and p21 synergistically limit the extent of hair follicle stem cell quiescence in vivo.

    Science.gov (United States)

    Lee, Jayhun; Hoi, Charlene S L; Lilja, Karin C; White, Brian S; Lee, Song Eun; Shalloway, David; Tumbar, Tudorita

    2013-03-19

    Mechanisms of tissue stem cell (SC) quiescence control are important for normal homeostasis and for preventing cancer. Cyclin-dependent kinase inhibitors (CDKis) are known inhibitors of cell cycle progression. We document CDKis expression in vivo during hair follicle stem cell (HFSC) homeostasis and find p21 (cyclin-dependent kinase inhibitor 1a, Cdkn1a), p57, and p15 up-regulated at quiescence onset. p21 appears important for HFSC timely onset of quiescence. Conversely, we find that Runx1 (runt related transcription factor 1), which is known for promoting HFSC proliferation, represses p21, p27, p57, and p15 transcription in HFSC in vivo. Intriguingly, in cell culture, tumors, and normal homeostasis, Runx1 and p21 interplay modulates proliferation in opposing directions under the different conditions. Unexpectedly, Runx1 and p21 synergistically limit the extent of HFSC quiescence in vivo, which antagonizes the role of p21 as a cell cycle inhibitor. Importantly, we find in cultured keratinocytes that Runx1 and p21 bind to the p15 promoter and synergistically repress p15 mRNA transcription, thereby restraining cell cycle arrest. This documents a surprising ability of a CDKi (p21) to act as a direct transcriptional repressor of another CDKi (p15). We unveil a robust in vivo mechanism that enforces quiescence of HFSCs, and a context-dependent role of a CDKi (p21) to limit quiescence of SCs, potentially by directly down-regulating mRNA levels of (an)other CDKi(s).

  17. Neutron star crustal cooling in KS 1731-260 14.5 years into quiescence

    CERN Document Server

    Merritt, Rachael L; Brown, Edward F; Page, Dany; Cumming, Andrew; Degenaar, Nathalie; Deibel, Alex; Homan, Jeroen; Miller, Jon M; Wijnands, Rudy

    2016-01-01

    Crustal cooling of accretion-heated neutron stars provides insight into the stellar interior of neutron stars. The neutron star X-ray transient, KS 1731-260, was in outburst for 12.5 years before returning to quiescence in 2001. We have monitored the cooling of this source since then through Chandra and XMM-Newton observations. Here, we present a 150 ks Chandra observation of KS 1731-260 taken in August 2015, about 14.5 years into quiescence, and 6 years after the previous observation. We find that the neutron star surface temperature is consistent with the previous observation, suggesting that crustal cooling has likely stopped and the crust has reached thermal equilibrium with the core. Using a theoretical crust thermal evolution code, we fit the observed cooling curves and constrain the core temperature (T$_c = 9.35\\pm0.25\\times10^7$ K), composition (Q$_{imp} = 4.4^{+2.2}_{-0.5}$) and level of extra shallow heating required (Q$_{sh} = 1.36\\pm0.18$ MeV/nucleon). We find that the presence of a low thermal co...

  18. NR2F1 controls tumor cell dormancy via SOX9 and RARβ driven quiescence programs

    Science.gov (United States)

    Sosa, Maria Soledad; Parikh, Falguni; Maia, Alexandre Gaspar; Estrada, Yeriel; Bosch, Almudena; Bragado, Paloma; Ekpin, Esther; George, Ajish; Zheng, Yang; Lam, Hung-Ming; Morrissey, Colm; Chung, Chi-Yeh; Farias, Eduardo F.; Bernstein, Emily; Aguirre-Ghiso, Julio A.

    2014-01-01

    Metastases can originate from disseminated tumor cells (DTCs), which may be dormant for years before reactivation. Here we find that the orphan nuclear receptor NR2F1 is epigenetically upregulated in experimental HNSCC dormancy models and in DTCs from prostate cancer patients carrying dormant disease for 7–18 years. NR2F1-dependent dormancy is recapitulated by a co-treatment with the DNA demethylating agent 5-Aza-C and retinoic acid across various cancer types. NR2F1-induced quiescence is dependent on SOX9, RARβ and CDK inhibitors. Intriguingly, NR2F1 induces global chromatin repression and the pluripotency gene NANOG, which contributes to dormancy of DTCs in the bone marrow. When NR2F1 is blocked in vivo, growth arrest or survival of dormant DTCs is interrupted in different organs. We conclude that NR2F1 is a critical node in dormancy induction and maintenance by integrating epigenetic programs of quiescence and survival in DTCs. PMID:25636082

  19. Optical/infrared observations of the X-ray burster KS1731-260 in quiescence

    CERN Document Server

    Zurita, C; Bandyopadhyay, R M; Cackett, E M; Groot, P J; Orosz, J A; Torres, M A P; Wijnands, R

    2010-01-01

    We performed an optical/infrared study of the counterpart of the low-mass X-ray binary KS1731-260 to test its identification and obtain information about the donor. Optical and infrared images of the counterpart of KS1731-260 were taken in two different epochs (2001 and 2007) after the source returned to quiescence in X-rays. We compared those observations with obtained when KS 1731-260 was still active. We confirm the identification of KS1731-260 with the previously proposed counterpart and improve its position to RA=17:34:13.46 and DEC=-26:05:18.60. The H-band magnitude of this candidate showed a decline of ~1.7 mags from outburst to quiescence. In 2007 April we obtained R=22.8+-0.1 and I=20.9+-0.1 for KS1731-260. Similar optical brightness was measured in June 2001 and July 2007. The intrinsic optical color R-I is consistent with spectral types from F to G for the secondary although there is a large excess over that from the secondary at the infrared wavelengths. This may be due to emission from the cooler...

  20. Laparoscopic Reversal of Hartmann’s Procedure: State of the Art 20 Years after the First Reported Case

    Directory of Open Access Journals (Sweden)

    Adriana Toro

    2014-01-01

    Full Text Available Introduction. Aim of the present work is to review the literature to point out the role of laparoscopic reversal of Hartmann procedure. Material and Methods. Number of patients, age, sex, etiology, Hinchey classification, interval between procedure and reversal, position of the first trocars, mean operative time (min, number and causes of conversion, length of stay, mortality, complications, and quality of life were considered. Results. 238 males (52.4% and 216 females (47.6% between 38 and 67 years were analyzed. The etiology was diverticulitis in 292 patients (72.1%, carcinoma in 43 patients (10.6%, and other in 70 patients (17.3%. Only 7 articles (22.6% reported Hinchey classification. The interval between initial procedure and reversal was between 50 and 330 days. The initial trocar was open positioned in 182 patients (43.2% through umbilical incision, in 177 patients (41.9% in right upper quadrant, and in 63 patients (14.9% in colostomy site. The operative time was between 69 and 285 minutes. A total of 83 patients (12.1% were converted and the causes were reported in 67.4%. The length of stay was between 3 and 12 days. 5 patients (0.7% died. The complications concern 112 cases (16.4%. Conclusion. The laparoscopic Hartmann’s reversal is safer and achieves faster positive results.

  1. High Resolution Polar Kerr Effect Measurements of Sr2RuO4: Evidence for Broken Time Reversal Symmetry in the Superconducting State

    Energy Technology Data Exchange (ETDEWEB)

    Xia, Jing

    2010-04-05

    Polar Kerr effect in the spin-triplet superconductor Sr{sub 2}RuO{sub 4} was measured with high precision using a Sagnac interferometer with a zero-area Sagnac loop. We observed non-zero Kerr rotations as big as 65 nanorad appearing below T{sub c} in large domains. Our results imply a broken time reversal symmetry state in the superconducting state of Sr{sub 2}RuO{sub 4}, similar to {sup 3}He-A.

  2. The 2015 Decay of the Black Hole X-Ray Binary V404 Cygni: Robust Disk-jet Coupling and a Sharp Transition into Quiescence

    Science.gov (United States)

    Plotkin, R. M.; Miller-Jones, J. C. A.; Gallo, E.; Jonker, P. G.; Homan, J.; Tomsick, J. A.; Kaaret, P.; Russell, D. M.; Heinz, S.; Hodges-Kluck, E. J.; Markoff, S.; Sivakoff, G. R.; Altamirano, D.; Neilsen, J.

    2017-01-01

    We present simultaneous X-ray and radio observations of the black hole X-ray binary V404 Cygni at the end of its 2015 outburst. From 2015 July 11–August 5, we monitored V404 Cygni with Chandra, Swift, and NuSTAR in the X-ray, and with the Karl G. Jansky Very Large Array and the Very Long Baseline Array in the radio, spanning a range of luminosities that were poorly covered during its previous outburst in 1989 (our 2015 campaign covers 2× {10}33≲ {L}{{X}}≲ {10}34 {erg} {{{s}}}-1). During our 2015 campaign, the X-ray spectrum evolved rapidly from a hard photon index of {{Γ }}≈ 1.6 (at {L}{{X}}≈ {10}34 {erg} {{{s}}}-1) to a softer {{Γ }}≈ 2 (at {L}{{X}}≈ 3× {10}33 {erg} {{{s}}}-1). We argue that V404 Cygni reaching {{Γ }}≈ 2 marks the beginning of the quiescent spectral state, which occurs at a factor of ≈3–4 higher X-ray luminosity than the average pre-outburst luminosity of ≈ 8× {10}32 {erg} {{{s}}}-1. V404 Cygni falls along the same radio/X-ray luminosity correlation that it followed during its previous outburst in 1989, implying a robust disk-jet coupling. We exclude the possibility that a synchrotron-cooled jet dominates the X-ray emission in quiescence, leaving synchrotron self-Compton from either a hot accretion flow or from a radiatively cooled jet as the most likely sources of X-ray radiation, and/or particle acceleration along the jet becoming less efficient in quiescence. Finally, we present the first indications of correlated radio and X-ray variability on minute timescales in quiescence, tentatively measuring the radio emission to lag the X-ray by 15+/- 4 minute, suggestive of X-ray variations propagating down a jet with a length of <3.0 au.

  3. From quiescence to unrest: 20 years of satellite geodetic measurements at Santorini volcano, Greece

    Science.gov (United States)

    Parks, Michelle M.; Moore, James D. P.; Papanikolaou, Xanthos; Biggs, Juliet; Mather, Tamsin A.; Pyle, David M.; Raptakis, Costas; Paradissis, Demitris; Hooper, Andrew; Parsons, Barry; Nomikou, Paraskevi

    2015-02-01

    Periods of unrest at caldera-forming volcanic systems characterized by increased rates of seismicity and deformation are well documented. Some can be linked to eventual eruptive activity, while others are followed by a return to quiescence. Here we use a 20 year record of interferometric synthetic aperture radar (InSAR) and GPS measurements from Santorini volcano to further our understanding of geodetic signals at a caldera-forming volcano during the periods of both quiescence and unrest, with measurements spanning a phase of quiescence and slow subsidence (1993-2010), followed by a phase of unrest (January 2011 to April 2012) with caldera-wide inflation and seismicity. Mean InSAR velocity maps from 1993-2010 indicate an average subsidence rate of 6 mm/yr over the southern half of the intracaldera island Nea Kameni. This subsidence can be accounted for by a combination of thermal contraction of the 1866-1870 lava flows and load-induced relaxation of the substrate. For the period of unrest, we use a joint inversion technique to convert InSAR measurements from three separate satellite tracks and GPS observations from 10 continuous sites into a time series of subsurface volume change. The optimal location of the inflating source is consistent with previous studies, situated north of Nea Kameni at a depth of 4 km. However, the time series reveals two distinct pressure pulses. The first pulse corresponds to a volume change (ΔV) within the shallow magma chamber of (11.56 ± 0.14) × 106 m3, and the second pulse has a ΔV of (9.73 ± 0.10) × 106 m3. The relationship between the timing of these pulses and microseismicity observations suggests that these pulses may be driven by two separate batches of magma supplied to a shallow reservoir. We find no evidence suggesting a change in source location between the two pulses. The decline in the rates of volume change at the end of both pulses and the observed lag of the deformation signal behind cumulative seismicity, suggest

  4. Seismic quiescence precursors to two M7 earthquakes on Sakhalin Island, measured by two methods

    Science.gov (United States)

    Wyss, Max; Sobolev, Gennady; Clippard, James D.

    2004-08-01

    Two large earthquakes occurred during the last decade on Sakhalin Island, the M w 7.6 Neftegorskoe earthquake of 27 May 1995 and the M w 6.8 Uglegorskoe earthquake of 4 August 2000, in the north and south of the island, respectively. Only about five seismograph stations record earthquakes along the 1000 km, mostly strike-slip plate boundary that transects the island from north to south. In spite of that, it was possible to investigate seismicity patterns of the last two to three decades quantitatively. We found that in, and surrounding, their source volumes, both of these main shocks were preceded by periods of pronounced seismic quiescence, which lasted 2.5 ± 0.5 years. The distances to which the production of earthquakes was reduced reached several hundred kilometers. The probability that these periods of anomalously low seismicity occurred by chance is estimated to be about 1% to 2%. These conclusions were reached independently by the application of two methods, which are based on different approaches. The RTL-algorithm measures the level of seismic activity in moving time windows by counting the number of earthquakes, weighted by their size, and inversely weighted by their distance, in time and space from the point of observation. The Z-mapping approach measures the difference of the seismicity rate, within moving time windows, to the background rate by the standard deviate Z. This generates an array of comparisons that cover all of the available time and space, and that can be searched for all anomalous departures from the normal seismicity rate. The RTL-analysis was based on the original catalog with K-classes measuring the earthquake sizes; the Z-mapping was based on the catalog with Ktransformed into magnitudes. The RTL-analysis started with data from 1980, the Z-mapping technique used the data from 1974 on. In both methods, cylindrical volumes, centered at the respective epicenters, were sampled. The Z-mapping technique additionally investigated the

  5. O-GlcNAc is required for the survival of primed pluripotent stem cells and their reversion to the naïve state.

    Science.gov (United States)

    Miura, Taichi; Nishihara, Shoko

    2016-10-27

    "Naïve" mouse embryonic stem cells (ESCs) are derived from pre-implantation embryos and possess pluripotency, the ability to differentiate into any cell type of the body. "Primed" mouse epiblast stem cells (EpiSCs) are also pluripotent but are derived from post-implantation embryos. ESC-derived EpiSCs (ESD-EpiSCs) are "primed" pluripotent stem cells and can revert to naïve reverted ESCs (rESCs). O-linked β-N-acetylglucosaminylation (O-GlcNAcylation) is a posttranslational modification in the cytoplasm and nucleus. O-GlcNAc is transferred to serine and threonine residues of proteins by O-GlcNAc transferase (Ogt) and removed from them by O-GlcNAcase (Oga). In naïve ESCs, O-GlcNAc contributes to maintain the undifferentiated state. In the transition from naïve state to primed state, Ogt maintains cell survival, whereas Oga has no function. However, the function of O-GlcNAc in primed ESD-EpiSCs and during the reversion from the primed state to naïve rESCs remains unclear. Here, we show that Ogt is required for the survival of primed ESD-EpiSCs. The expression of cytosolic Oga was significantly increased during induction from naïve ESCs to primed ESD-EpiSCs. Furthermore, both Ogt and Oga were required for the reversion from primed ESD-EpiSCs to naïve rESCs. These findings indicate that O-GlcNAcylation plays an important role in the survival of primed ESD-EpiSCs and in their reversion to naïve rESCs.

  6. FRPR-4 Is a G-Protein Coupled Neuropeptide Receptor That Regulates Behavioral Quiescence and Posture in Caenorhabditis elegans.

    Directory of Open Access Journals (Sweden)

    Matthew D Nelson

    Full Text Available Neuropeptides signal through G-protein coupled receptors (GPCRs to regulate a broad array of animal behaviors and physiological processes. The Caenorhabditis elegans genome encodes approximately 100 predicted neuropeptide receptor GPCRs, but in vivo roles for only a few have been identified. We describe here a role for the GPCR FRPR-4 in the regulation of behavioral quiescence and locomotive posture. FRPR-4 is activated in cell culture by several neuropeptides with an amidated isoleucine-arginine-phenylalanine (IRF motif or an amidated valine-arginine-phenylalanine (VRF motif at their carboxy termini, including those encoded by the gene flp-13. Loss of frpr-4 function results in a minor feeding quiescence defect after heat-induced cellular stress. Overexpression of frpr-4 induces quiescence of locomotion and feeding as well as an exaggerated body bend posture. The exaggerated body bend posture requires the gene flp-13. While frpr-4 is expressed broadly, selective overexpression of frpr-4 in the proprioceptive DVA neurons results in exaggerated body bends that require flp-13 in the ALA neuron. Our results suggest that FLP-13 and other neuropeptides signal through FRPR-4 and other receptors to regulate locomotion posture and behavioral quiescence.

  7. Regulation of Mammary Stem Cell Quiescence via Post-Translational Modification of DeltaNp63alpha

    Science.gov (United States)

    2014-02-01

    were collected by centrifugation and lysed by sonication in the presence of a cocktail of protease inhibitors. Lysates were cleared by centrifugation...Cherukuri P, Li H, Yuan Z, et al. (2008) Reciprocal intraepithelial interactions between TP63 and hedgehog signaling regulate quiescence and activation of

  8. Retinoic acid-induced pancreatic stellate cell quiescence reduces paracrine Wnt-beta-catenin signaling to slow tumor progression

    NARCIS (Netherlands)

    Froeling, F.E.; Feig, C.; Chelala, C.; Dobson, R.; Mein, C.E.; Tuveson, D.A.; Clevers, H.; Hart, I.R.; Kocher, H.M.

    2011-01-01

    BACKGROUND & AIMS: Patients with pancreatic ductal adenocarcinoma are deficient in vitamin A, resulting in activation of pancreatic stellate cells (PSCs). We investigated whether restoration of retinol to PSCs restores their quiescence and affects adjacent cancer cells. METHODS: PSCs and cancer cell

  9. Characterizing X-Ray and Radio Emission in the Black Hole X-Ray Binary V404 Cygni During Quiescence

    DEFF Research Database (Denmark)

    Rana, Vikram; Loh, Alan; Corbel, Stephane

    2016-01-01

    We present results from multi-wavelength simultaneous X-ray and radio observations of the black hole X-ray binary V404 Cyg in quiescence. Our coverage with NuSTAR provides the very first opportunity to study the X-ray spectrum of V404 Cyg at energies above 10 keV. The unabsorbed broadband (0.3–30...

  10. Further X-ray observations of EXO 0748-676 in quiescence: evidence for a cooling neutron star crust

    NARCIS (Netherlands)

    N. Degenaar; M.T. Wolff; P.S. Ray; K.S. Wood; J. Homan; W.H.G. Lewin; P.G. Jonker; E.M. Cackett; J.M. Miller; E.F. Brown; R. Wijnands

    2011-01-01

    In late 2008, the quasi-persistent neutron star X-ray transient and eclipsing binary EXO 0748−676 started a transition from outburst to quiescence, after it actively accreted for more than 24 yr. In a previous work, we discussed Chandra and Swift observations obtained during the first 5 months of th

  11. Characterizing X-Ray and Radio Emission in the Black Hole X-Ray Binary V404 Cygni During Quiescence

    DEFF Research Database (Denmark)

    Rana, Vikram; Loh, Alan; Corbel, Stephane

    2016-01-01

    We present results from multi-wavelength simultaneous X-ray and radio observations of the black hole X-ray binary V404 Cyg in quiescence. Our coverage with NuSTAR provides the very first opportunity to study the X-ray spectrum of V404 Cyg at energies above 10 keV. The unabsorbed broadband (0...

  12. Chandra and Swift observations of the quasi-persistent neutron star transient EXO 0748−676 back to quiescence

    NARCIS (Netherlands)

    N. Degenaar; R. Wijnands; M.T. Wolff; P.S. Ray; K.S. Wood; J. Homan; W.H.G. Lewin; P.G. Jonker; E.M. Cackett; J.M. Miller; E.F. Brown

    2009-01-01

    The quasi-persistent neutron star X-ray transient and eclipsing binary EXO 0748-676 recently started the transition to quiescence following an accretion outburst that lasted more than 24 years. We report on two Chandra and 12 Swift observations performed within five months after the end of the outbu

  13. Endogenous transforming growth factor-beta promotes quiescence of primary microglia in vitro

    DEFF Research Database (Denmark)

    Spittau, Björn; Wullkopf, Lena; Zhou, Xiaolai

    2013-01-01

    of TGFβ1 results in increased microgliosis and neurodegeneration in mice which indicates that TGFβ1 is an important regulator of microglial functions in vivo. Here, we addressed the role of endogenous TGFβ signaling for microglia in vitro. We clearly demonstrate active TGFβ signaling in primary microglia...... in TGFβ1 processing, its extracellular storage as well as activation of latent TGFβ. Finally, we demonstrate that pharmacological inhibition of microglial TGFβ signaling resulted in upregulation of the proinflammatory markers IL6 and iNOS and downregulation of the alternative activation markers Arg1...... and Ym1 in vitro. Together, these data clearly show that endogenous TGFβ1 and autocrine TGFβ signaling is important for microglial quiescence in vitro and further suggest the upregulation of TGFβ1 in neurodegenerative diseases as a mechanism to regulate microglia functions and silence neuroinflammation....

  14. Timing of transcriptional quiescence during gametogenesis is controlled by global histone H3K4 demethylation.

    Science.gov (United States)

    Xu, Mengshu; Soloveychik, Maria; Ranger, Mathieu; Schertzberg, Michael; Shah, Zarna; Raisner, Ryan; Venkatasubrahmanyan, Shivkumar; Tsui, Kyle; Gebbia, Marinella; Hughes, Tim; van Bakel, Harm; Nislow, Corey; Madhani, Hiten D; Meneghini, Marc D

    2012-11-13

    Gametes are among the most highly specialized cells produced during development. Although gametogenesis culminates in transcriptional quiescence in plants and animals, regulatory mechanisms controlling this are unknown. Here, we confirm that gamete differentiation in the single-celled yeast Saccharomyces cerevisiae is accompanied by global transcriptional shutoff following the completion of meiosis. We show that Jhd2, a highly conserved JARID1-family histone H3K4 demethylase, activates protein-coding gene transcription in opposition to this programmed transcriptional shutoff, sustaining the period of productive transcription during spore differentiation. Moreover, using genome-wide nucleosome, H3K4me, and transcript mapping experiments, we demonstrate that JHD2 globally represses intergenic noncoding transcription during this period. The widespread transcriptional defects of JHD2 mutants are associated with precocious differentiation and the production of stress-sensitive spores, demonstrating that Jhd2 regulation of the global postmeiotic transcriptional program is critical for the production of healthy meiotic progeny.

  15. Azobenzene-derived tris-β-diketonate lanthanide complexes: reversible trans-to-cis photoisomerization in solution and solid state.

    Science.gov (United States)

    Lin, Li-Rong; Wang, Xuan; Wei, Gao-Ning; Tang, Hui-Hui; Zhang, Hui; Ma, Li-Hua

    2016-10-14

    Novel azobenzene-derived β-diketonates (4,4,5,5,6,6,6-heptafluoro-1-azobenzene-1,3-hexanedione (LA), 4,4,5,5,6,6,6-heptafluoro-1-(4-dimethylamino)azobenzene-1,3-hexanedione (LB)) were designed and their complexes with lanthanide cations (La(3+), Eu(3+), Gd(3+), Yb(3+)) were prepared and characterized by (1)H NMR, FT-IR, and elemental analysis. Three of the complexes were crystallized successfully and identified by X-ray diffraction. It was significant to find that LA showed remarkably reversible trans-to-cis isomerization properties, however, LB, bearing an electron donor compared with LA, slowed down the isomerization to an extent. The presence of Ln(iii) enhanced the reversible trans-to-cis isomerization properties of both LA and LB a little upon photoirradiation in organic solvents, and amazingly increased the fatigue resistance. In addition, the complexes doped in polymethyl methacrylate (PMMA) films produced a similar phenomenon as well as when in solution. Theoretical calculations based on time dependent density functional theory (TD-DFT) were performed for geometry optimization and to determine the excitation energies of LA and LB to gain further insight into the electronic structure of the complexes, and the data were consistent with the experimental results. The excellent reversible photoisomerization properties of the newly designed Ln(iii) complexes can offer important advantages that will help with the further study of these materials to reach their full potential in applications such as molecular switching devices.

  16. A pressure-driven model for the quasi periodical oscillations of the Single Helical States in Reversed Field Pinch plasmas

    Science.gov (United States)

    Paccagnella, Roberto

    2013-10-01

    In this work a model that could explain the experimentally observed quasi periodical oscillations in electron temperature and perturbed magnetic field in a Reversed Field Pinch is discussed. An ohmically heated plasma in which an interplay between thermal conduction and heat transport, on one side, and the magneto-hydro-dynamical stability, on the other side, is studied. It is shown that, by making some simple and physically reasonable assumptions, a set of equations can be obtained showing a variety of periodical or quasi periodical oscillations for the relevant dynamical variables.

  17. Long-Term Seismic Quiescences and Great Earthquakes in and Around the Japan Subduction Zone Between 1975 and 2012

    Science.gov (United States)

    Katsumata, Kei

    2016-10-01

    An earthquake catalog created by the International Seismological Center (ISC) was analyzed, including 3898 earthquakes located in and around Japan between January 1964 and June 2012 shallower than 60 km with the body wave magnitude of 5.0 or larger. Clustered events such as earthquake swarms and aftershocks were removed from the ISC catalog by using a stochastic declustering method based on Epidemic-Type Aftershock Sequence (ETAS) model. A detailed analysis of the earthquake catalog using a simple scanning technique (ZMAP) shows that the long-term seismic quiescences lasting more than 9 years were recognized ten times along the subduction zone in and around Japan. The three seismic quiescences among them were followed by three great earthquakes: the 1994 Hokkaido-toho-oki earthquake (M w 8.3), the 2003 Tokachi-oki earthquake (M w 8.3), and the 2011 Tohoku earthquake (M w 9.0). The remaining seven seismic quiescences were followed by no earthquake with the seismic moment M 0 ≥ 3.0 × 1021 Nm (M w 8.25), which are candidates of the false alarm. The 2006 Kurile Islands earthquake (M w 8.3) was not preceded by the significant seismic quiescence, which is a case of the surprise occurrence. As a result, when limited to earthquakes with the seismic moment of M 0 ≥ 3.0 × 1021 Nm, four earthquakes occurred between 1976 and 2012 in and around Japan, and three of them were preceded by the long-term seismic quiescence lasting more than 9 years.

  18. Long-Term Seismic Quiescences and Great Earthquakes in and Around the Japan Subduction Zone Between 1975 and 2012

    Science.gov (United States)

    Katsumata, Kei

    2017-06-01

    An earthquake catalog created by the International Seismological Center (ISC) was analyzed, including 3898 earthquakes located in and around Japan between January 1964 and June 2012 shallower than 60 km with the body wave magnitude of 5.0 or larger. Clustered events such as earthquake swarms and aftershocks were removed from the ISC catalog by using a stochastic declustering method based on Epidemic-Type Aftershock Sequence (ETAS) model. A detailed analysis of the earthquake catalog using a simple scanning technique (ZMAP) shows that the long-term seismic quiescences lasting more than 9 years were recognized ten times along the subduction zone in and around Japan. The three seismic quiescences among them were followed by three great earthquakes: the 1994 Hokkaido-toho-oki earthquake ( M w 8.3), the 2003 Tokachi-oki earthquake ( M w 8.3), and the 2011 Tohoku earthquake ( M w 9.0). The remaining seven seismic quiescences were followed by no earthquake with the seismic moment M 0 ≥ 3.0 × 1021 Nm ( M w 8.25), which are candidates of the false alarm. The 2006 Kurile Islands earthquake ( M w 8.3) was not preceded by the significant seismic quiescence, which is a case of the surprise occurrence. As a result, when limited to earthquakes with the seismic moment of M 0 ≥ 3.0 × 1021 Nm, four earthquakes occurred between 1976 and 2012 in and around Japan, and three of them were preceded by the long-term seismic quiescence lasting more than 9 years.

  19. The Historical X-ray Transient KY TrA in quiescence

    Science.gov (United States)

    Zurita, C.; Corral-Santana, J. M.; Casares, J.

    2015-12-01

    We present deep optical images of the historical X-ray Transient KY TrA in quiescence from which we confirm the identification of the counterpart reported by Murdin et al. and derive an improved position of α = 15:28:16.97 and δ = -61:52:57.8. In 2007 June we obtained I, R and V images, where the counterpart seems to be double indicating the presence of an interloper at ˜1.4 arcsec NW. After separating the contribution of KY TrA we calculate I = 21.47 ± 0.09, R = 22.3 ± 0.1 and V = 23.6 ± 0.1. Similar brightness in the I-band was measured in 2004 May and 2010 June. Variability was analysed from series of images taken in 2004, spanning 0.6 h, and in two blocks of 6 h during 2007. We find that the target is not variable in any data set above the error levels ˜0.07 mags. The presence of the interloper might explain the non-detection of the classic ellipsoidal modulation; our data indicates that it contributes around half of the total flux, which would make a variation donor star of K2 = 630 ± 74 km s-1. Based on the outburst amplitude and colours of the optical counterpart in quiescence we derive a crude estimate of the orbital period of 8 h and an upper limit of 15 h which would lead to mass function estimates of ≈9 M⊙ and <16 M⊙, respectively.

  20. Focal neuronal loss, reversible subcortical focal T2 hypointensity in seizures with a nonketotic hyperglycemic hyperosmolar state

    Energy Technology Data Exchange (ETDEWEB)

    Raghavendra, S.; Ashalatha, R.; Thomas, Sanjeev V. [Sree Chitra Tirunal Institute for Medical Sciences and Technology, Department of Neurology, Trivandrum, Kerala (India); Kesavadas, C. [Sree Chitra Tirunal Institute for Medical Sciences and Technology, Department of Imaging Sciences and Interventional Radiology, Trivandrum (India)

    2007-04-15

    Neuroimaging in seizures associated with nonketotic hyperglycemia (NKH) is considered normal. We report magnetic resonance imaging (MRI) abnormalities in four patients with NKH and seizures. We prospectively evaluated clinical and radiological abnormalities in four patients with NKH during the period March 2004 to December 2005. All patients presented with seizures, either simple or complex partial seizures or epilepsia partialis continua. Two of them had transient hemianopia. MRI showed subcortical T2 hypointensity in the occipital white matter and in or around the central sulcus (two patients each), T2 hyperintensity of the overlying cortex (two patients), focal overlying cortical enhancement (three patients) and bilateral striatal hyperintensity (one patient). Diffusion-weighted imaging (DWI) performed in three patients showed restricted diffusion. The ictal semiology and electroencephalographic (EEG) findings correlated with the MRI abnormalities. On clinical recovery, the subcortical T2 hypointensity and striatal hyperintensity reversed in all patients. The initial cortical change evolved to FLAIR hyperintensity suggestive of focal cortical gliosis. The radiological differential diagnosis considered initially included encephalitis, malignancy and hemorrhagic infarct rendering a diagnostic dilemma. We identified subcortical T2 hypointensity rather than hyperintensity as a characteristic feature of seizures associated with NKH. Only very few similar reports exist in literature. Reversible bilateral striatal T2 hyperintensity in NKH has not been reported to the best of our knowledge. (orig.)

  1. Aspects of Majorana Bound States in One-Dimensional Systems with and without Time-Reversal Symmetry

    DEFF Research Database (Denmark)

    Wölms, Konrad Udo Hannes

    bound states in the measurement still has to be understood better. And example would be the frequently performed tunnel probe measurement on Majorana bound states [26, 40, 41]. A second reason why Majorana bound states are interesting is their potential application to a certain quantum computation...... scheme. This scheme, called topological quantum computation, relies on the braiding of so-called non-abelian anyons in order to perform computations [18]. Majorana bound states are the simplest example of such non-abelian anyons. No other non-abelian anyons have been realized experimentally yet, which...... puts further focus on the study of Majorana bound states. Additionally to probing Majorana bound states, their use in topological quantum computation also requires them to be manipulated. This also poses an interesting problem for both experimentalists and theorists [25, 27]. We can summarize...

  2. Reverse logistics

    NARCIS (Netherlands)

    M.P. de Brito (Marisa); S.D.P. Flapper; R. Dekker (Rommert)

    2002-01-01

    textabstractThis paper gives an overview of scientific literature that describes and discusses cases of reverse logistics activities in practice. Over sixty case studies are considered. Based on these studies we are able to indicate critical factors for the practice of reverse logistics. In addi

  3. Aspects of Majorana Bound States in One-Dimensional Systems with and without Time-Reversal Symmetry

    DEFF Research Database (Denmark)

    Wölms, Konrad Udo Hannes

    In recent years there has been a lot of interest in topological phases of matter. Unlike conventional phases of matter, topological phases are not distinguished by symmetries, but by so-called topological invariants which have more subtle physical implications. It comes therefore as no surprise......-dimensions without any symmetries. Even though the bulk of a quantum Hall system is insulating, it exhibits gapless edge modes. It is therefore dierent from other insulating two-dimensional materials. It was soon realized after the discovery of the quantum Hall eect, that there is a quantized invariant (topological...... of the topological phases that received a lot of attention in recent years, is the one-dimensional topological superconducting phase, without time-reversal symmetry [5]. Similar to the quantum Hall eect, this phase exhibits edge excitations, which are zerodimensional for one-dimensional systems. For this particular...

  4. Adaptive Pairing Reversible Watermarking.

    Science.gov (United States)

    Dragoi, Ioan-Catalin; Coltuc, Dinu

    2016-05-01

    This letter revisits the pairwise reversible watermarking scheme of Ou et al., 2013. An adaptive pixel pairing that considers only pixels with similar prediction errors is introduced. This adaptive approach provides an increased number of pixel pairs where both pixels are embedded and decreases the number of shifted pixels. The adaptive pairwise reversible watermarking outperforms the state-of-the-art low embedding bit-rate schemes proposed so far.

  5. A reversible early oxidized redox state that precedes macromolecular ROS damage in aging non-transgenic and 3xTg-AD mouse neurons

    Science.gov (United States)

    Ghosh, D.; LeVault, K.; Barnett, A.; Brewer, G.J.

    2012-01-01

    The brain depends on redox electrons from NADH to produce ATP and oxyradicals (ROS). Since ROS damage and mitochondrial dysregulation are prominent in aging and Alzheimer’s disease (AD) and their relationship to redox state is unclear, we wanted to know whether an oxidative redox shift precedes these markers and leads to macromolecular damage in a mouse model of AD. We used the 3xTg-AD mouse model that displays cognitive deficits beginning at 4 months. Hippocampal/cortical neurons were isolated across the age-span and cultured in common nutrients to control for possible hormonal and vascular differences. We found an increase of NAD(P)H levels and redox state in non-transgenic neurons until middle age, followed by a decline in old age. The 3xTg-AD neurons maintained much lower resting NAD(P)H and redox state after 4 months, but the NADH regenerating capacity continuously declined with age beginning at 2 months. These redox characteristics were partially reversible with nicotinamide, a biosynthetic precursor of NAD+. Nicotinamide also protected against glutamate excitotoxicity. Compared to non-transgenic neurons, 3xTg-AD neurons possessed more mitochondria/neuron and lower glutathione levels which preceeded age-related increases in ROS levels. These glutathione deficits were again reversible with nicotinamide in 3xTg-AD neurons. Surprisingly, low macromolecular ROS damage was only elevated after 4 months in the 3xTg-AD neurons if anti-oxidants were removed. The present data suggest that a more oxidized redox state and a lower antioxidant glutathione defense can be dissociated from neuronal ROS damage, changes that precede the onset of cognitive deficits in the 3xTg-AD model. PMID:22539844

  6. Reversibility of cellular aging by reprogramming through an embryonic-like state : a new paradigm for human cell rejuvenation

    Directory of Open Access Journals (Sweden)

    Jean-Marc Lemaitre

    2014-01-01

    Full Text Available Direct reprogramming of somatic cells into induced pluripotent stem cells (iPSCs provides a unique opportunity to derive patient-specific stem cells with potential application in autologous tissue replacement therapies and without the ethical concerns of Embryonic Stem Cells (hESC. However, this strategy still suffers from several hurdles that need to be overcome before clinical applications. Among them, cellular senescence, which contributes to aging and restricted longevity, has been described as a barrier to the derivation of iPSCs. This suggests that aging might be an important limitation for therapeutic purposes for elderly individuals. Senescence is characterized by an irreversible cell cycle arrest in response to various forms of stress, including activation of oncogenes, shortened telomeres, DNA damage, oxidative stress, and mitochondrial dysfunction. To overcome this barrier, we developed an optimized 6-factor-based reprogramming protocol that is able to cause efficient reversing of cellular senescence and reprogramming into iPSCs. We demonstrated that iPSCs derived from senescent and centenarian fibroblasts have reset telomere size, gene expression profiles, oxidative stress, and mitochondrial metabolism, and are indistinguishable from hESC. Finally, we demonstrate that re-differentiation led to rejuvenated cells with a reset cellular physiology, defining a new paradigm for human cell rejuvenation. We discuss the molecular mechanisms involved in cell reprogramming of senescent cells. 

  7. Reverse energy partitioning—An efficient algorithm for computing the density of states, partition functions, and free energy of solids

    Science.gov (United States)

    Do, Hainam; Wheatley, Richard J.

    2016-08-01

    A robust and model free Monte Carlo simulation method is proposed to address the challenge in computing the classical density of states and partition function of solids. Starting from the minimum configurational energy, the algorithm partitions the entire energy range in the increasing energy direction ("upward") into subdivisions whose integrated density of states is known. When combined with the density of states computed from the "downward" energy partitioning approach [H. Do, J. D. Hirst, and R. J. Wheatley, J. Chem. Phys. 135, 174105 (2011)], the equilibrium thermodynamic properties can be evaluated at any temperature and in any phase. The method is illustrated in the context of the Lennard-Jones system and can readily be extended to other molecular systems and clusters for which the structures are known.

  8. Patchiness in wind erosion-deposition patterns in response to a recent state change reversal in the Chihuahuan Desert

    Science.gov (United States)

    Shifts from shrub-dominated states to grasslands are believed to be irreversible as a result of positive feedbacks between woody plants and soil properties. In the Chihuahuan Desert, mesquite (Prosopis glandulosa) expansion into black grama (Bouteloua eriopoda) grasslands is maintained by wind redis...

  9. Secular changes in the quiescence of WZ Sge: the development of a cavity in the inner disk

    CERN Document Server

    Kuulkers, E; Honeycutt, R K; Skidmore, W; Waagen, E O; Wynn, G A

    2010-01-01

    We find a dimming during optical quiescence of the cataclysmic variable WZ Sge by about half a magnitude in between superoutbursts. We connect the dimming with the development of a cavity in the inner part of the accretion disk. We suggest that when the cavity is big enough, accretion of material is governed by the magnetic field of the white dwarf and pulsations from the weakly magnetic white dwarf appear. The time scale of forming the cavity is about a decade and it persists throughout the whole quiescent phase. Such a cavity can be well accommodated by the proposed magnetic propeller model for WZ Sge, where during quiescence mass is being expelled by the magnetic white dwarf from the inner regions of the accretion disk to larger radii.

  10. X-ray Free Electron Laser Determination of Crystal Structures of Dark and Light States of a Reversibly Photoswitching Fluorescent Protein at Room Temperature

    Directory of Open Access Journals (Sweden)

    Christopher D. M. Hutchison

    2017-09-01

    Full Text Available The photochromic fluorescent protein Skylan-NS (Nonlinear Structured illumination variant mEos3.1H62L is a reversibly photoswitchable fluorescent protein which has an unilluminated/ground state with an anionic and cis chromophore conformation and high fluorescence quantum yield. Photo-conversion with illumination at 515 nm generates a meta-stable intermediate with neutral trans-chromophore structure that has a 4 h lifetime. We present X-ray crystal structures of the cis (on state at 1.9 Angstrom resolution and the trans (off state at a limiting resolution of 1.55 Angstrom from serial femtosecond crystallography experiments conducted at SPring-8 Angstrom Compact Free Electron Laser (SACLA at 7.0 keV and 10.5 keV, and at Linac Coherent Light Source (LCLS at 9.5 keV. We present a comparison of the data reduction and structure determination statistics for the two facilities which differ in flux, beam characteristics and detector technologies. Furthermore, a comparison of droplet on demand, grease injection and Gas Dynamic Virtual Nozzle (GDVN injection shows no significant differences in limiting resolution. The photoconversion of the on- to the off-state includes both internal and surface exposed protein structural changes, occurring in regions that lack crystal contacts in the orthorhombic crystal form.

  11. THE SIGN REVERSAL AND SCALING RELATIONS OF HALL ANOMALY IN THE MIXED STATE TYPE-II SUPERCONDUCTORS

    Institute of Scientific and Technical Information of China (English)

    WEI YEU CHEN; MING JU CHOU; HUANG ZHONG BING

    2000-01-01

    We present a new model for the anomalous Hall effect in the mixed state of type-II superconductors. In this model we consider the thermally activated motion of the many body correlating vortex lattice system. The sign change of the Hall resistivity is the result of the competition between the motion of effective antivortices and the motion of the pinned vortex lattice together with the interstitial vortices. Within this model many essential experimental results for the complicated Hall effect can be explained.

  12. Optical spectroscopy of EX Lupi during quiescence and outburst: Infall, wind, and dynamics in the accretion flow

    CERN Document Server

    Sicilia-Aguilar, Aurora; Setiawan, Johny; Ábrahám, Péter; Dullemond, Cornelis; Eiroa, Carlos; Goto, Miwa; Henning, Thomas; Júhasz, Attila

    2012-01-01

    We explore the accretion mechanisms in EX Lupi, prototype of EXor variables, during its quiescence and outburst phases. We analyse high-resolution optical spectra taken before, during, and after its 2008 outburst. In quiescence and outburst, the star presents many permitted emission lines, including typical CTTS lines and numerous neutral and ionized metallic lines. During the outburst, the number of emission lines increases to over a thousand, with narrow plus broad component structure (NC+BC). The BC profile is highly variable on short timescales (24-72h). An active chromosphere can explain the metallic lines in quiescence and the outburst NC. The dynamics of the BC line profiles suggest an origin in a hot, dense, non-axisymmetric, and non-uniform accretion column that suffers velocity variations along the line-of-sight on timescales of days. Assuming Keplerian rotation, the emitting region would be located at ~0.1-0.2 AU, consistent with the inner disk rim, but the velocity profiles of the lines reveal a c...

  13. Hedgehog Controls Quiescence and Activation of Neural Stem Cells in the Adult Ventricular-Subventricular Zone

    Directory of Open Access Journals (Sweden)

    Mathieu Daynac

    2016-10-01

    Full Text Available Identifying the mechanisms controlling quiescence and activation of neural stem cells (NSCs is crucial for understanding brain repair. Here, we demonstrate that Hedgehog (Hh signaling actively regulates different pools of quiescent and proliferative NSCs in the adult ventricular-subventricular zone (V-SVZ, one of the main brain neurogenic niches. Specific deletion of the Hh receptor Patched in NSCs during adulthood upregulated Hh signaling in quiescent NSCs, progressively leading to a large accumulation of these cells in the V-SVZ. The pool of non-neurogenic astrocytes was not modified, whereas the activated NSC pool increased after a short period, before progressively becoming exhausted. We also showed that Sonic Hedgehog regulates proliferation of activated NSCs in vivo and shortens both their G1 and S-G2/M phases in culture. These data demonstrate that Hh orchestrates the balance between quiescent and activated NSCs, with important implications for understanding adult neurogenesis under normal homeostatic conditions or during injury.

  14. Electromagnetic spin down of a transient accreting millisecond pulsar during quiescence

    CERN Document Server

    Melatos, Andrew

    2015-01-01

    The measured spin-down rates in quiescence of the transient accreting millisecond pulsars IGR J00291+5934, XTE J1751-305, SAX J1808.4-3658, and Swift J1756.9-2508 have been used to estimate the magnetic moments of these objects assuming standard magnetic dipole braking. It is shown that this approach leads to an overestimate, if the amount of residual accretion is enough to distort the magnetosphere away from a force-free configuration, through magnetospheric mass loading or crushing, so that the lever arm of the braking torque migrates inside the light cylinder. We derive an alternative spin-down formula and calculate the residual accretion rates where the formula is applicable. As a demonstration, we apply the alternative spin-down formula to produce updated magnetic moment estimates for the four objects above. We note that, based on current uncertain observations of quiescent accretion rates, magnetospheric mass loading and crushing are neither firmly indicated nor ruled out in these four objects. Because ...

  15. The role of magnetic field for quiescence-outburst models in CVs

    CERN Document Server

    De Bianchi, S; Gaudenzi, S

    2014-01-01

    In this paper we present the elementary assumptions of our research on the role of the magnetic field in modelling the quiescence-outbursts cycle in Cataclysmic Variables (CVs). The behaviour of the magnetic field is crucial not only to integrate the disk instability model (Osaki 1974), but also to determine the cause and effect nexus among parameters affecting the behavior of complex systems. On the ground of our interpretation of the results emerging from the literature, we suggest that in models describing DNe outbursts, such as the disk instability model, the secondary instability model (Bath 1973) and the thermonuclear runaway model (Mitrofanov 1978), the role of the magnetic field is at least twofold. On the one hand, it activates a specific dynamic pathway for the accreting matter by channelling it. On the other hand, it could be indirectly responsible for switching a particular outburst modality. In order to represent these two roles of the magnetic field, we need to integrate the disk instability mod...

  16. Angiography of the corpus cavernosum penis in the pony stallion during erection and quiescence.

    Science.gov (United States)

    Bartels, J E; Beckett, S D; Brown, B G

    1984-07-01

    Serial arteriography was used to determine the vascular pattern and blood flow in the penis of the pony stallion. Ponies were anesthetized with pentobarbital sodium, and catheters were surgically introduced into the internal pudendal and obturator arteries. The vascular anatomy was visualized by angiography via image-intensified fluoroscopy and was recorded on 70-mm film at 3 frames/s or by direct radiography. Blood flow into the corpus cavernosum penis (CCP) was limited during quiescence because the blood was immediately shunted into the venous system. After vasodilation with mild stimulation from an electroejaculator, there was increased filling of the CCP and corpus spongiosum penis. Contrast medium injected into the internal pudendal artery entered the bulb of the penis during peak erection, but medium injected into the obturator artery could not enter the crus penis during peak erection. The contrast medium stopped in the obturator artery at the edge of the ischiocavernous muscles due to the occlusion of the deep arteries of the penis by contraction of these muscles. When contrast medium was injected directly into the CCP near the glans to outline the body of the penis, there was no evidence of venous outlets along the body.

  17. The First X-ray Measurement Of SAX J1750.8-2900 In Quiescence

    Science.gov (United States)

    Lowell, Alexander W.; Tomsick, J.; Bodaghee, A.; Boggs, S.; Heinke, C.; Kaaret, P.; Chaty, S.; Rodriguez, J.; Walter, R.

    2011-09-01

    We have performed the first sensitive X-ray observation of the low-mass X-ray binary (LMXB) SAX J1750.8-2900 in quiescence with XMM-Newton. Both a classical black body model and a non-magnetized, pure hydrogen neutron star (NS) atmosphere model were fit to the 0.3-12.0 keV spectrum. In addition, a power law component was added to the model in order to search for evidence of harder emission not accounted for by the thermal component. Assuming a previously measured upper limit on the distance to SAX J1750.8-2900 of 6.3 +/- 0.7 kpc, we find that the upper limit for the luminosity of this source is 8.1 (+1.9) (-1.8) E33 erg/s for the NS atmosphere model, and 2.3 (+0.9) (-0.5) E33 erg/s for the black body model. We conclude that the power law contribution to the total luminosity is low, and we discuss implications for the origin of the power-law that is present in some systems. Although many quiescent NS transients show evidence for enhanced cooling, the quiescent luminosity for SAX J1750.8-2900 may be high enough that the standard cooling scenario may be sufficient.

  18. Quenching vs. Quiescence: forming realistic massive ellipticals with a simple starvation model

    Science.gov (United States)

    Gutcke, Thales A.; Macciò, Andrea V.; Dutton, Aaron A.; Stinson, Greg S.

    2017-01-01

    The decrease in star formation (SF) and the morphological change necessary to produce the z = 0 elliptical galaxy population are commonly ascribed to a sudden quenching event, which is able to rid the central galaxy of its cold gas reservoir in a short time. Following this event, the galaxy is able to prevent further SF and stay quiescent via a maintenance mode. We test whether such a quenching event is truly necessary using a simple model of quiescence. In this model, hot gas (all gas above a temperature threshold) in a ˜1012 M⊙ halo mass galaxy at redshift z ˜ 3 is prevented from cooling. The cool gas continues to form stars at a decreasing rate and the galaxy stellar mass, morphology, velocity dispersion and position on the color magnitude diagram (CMD) proceed to evolve. By z = 0, the halo mass has grown to 1013 M⊙ and the galaxy has attained characteristics typical of an observed z = 0 elliptical galaxy. Our model is run in the framework of a cosmological, smooth particle hydrodynamic code which includes SF, early stellar feedback, supernova feedback, metal cooling and metal diffusion. Additionally, we post-process our simulations with a radiative transfer code to create a mock CMD. In contrast to previous assumptions that a pure "fade away" model evolves too slowly to account for the sparsity of galaxies in the "green valley", we demonstrate crossing times of ≲ 1 Gyr. We conclude that no sudden quenching event is necessary to produce such rapid colour transitions.

  19. VLT spectroscopy of the Black Hole Candidate Swift J1357.2-0933 in Quiescence

    CERN Document Server

    Torres, M A P; Miller-Jones, J C A; Steeghs, D; Repetto, S; Wu, Jianfeng

    2015-01-01

    We present time-resolved optical spectroscopy of the counterpart to the high-inclination black hole low-mass X-ray binary Swift J1357.2-0933 in quiescence. Absorption features from the mass donor star were not detected. Instead the spectra display prominent broad double-peaked Halpha emission and weaker HeI emission lines. From the Halpha peak-to-peak separation we constrain the radial velocity semi-amplitude of the donor star to > 789 km/s. Further analysis through radial velocity and equivalent width measurements indicates that the Halpha line is free of variability due to S-wave components or disc eclipses. From our data and previous observations during outburst, we conclude that long-term radial velocity changes ascribed to a precessing disc were of low amplitude or not present. This implies that the centroid position of the line should closely represent the systemic radial velocity. Using the derived systemic velocity of -150 km/s and the best available limits on the source distance, we infer that the bl...

  20. The Historical X-ray Transient KY TrA in quiescence

    CERN Document Server

    Zurita, C; Casares, J

    2015-01-01

    We present deep optical images of the historical X-ray Transient KY TrA in quiescence from which we confirm the identification of the counterpart reported by Murdin (1977) and derive an improved position of alpha=15:28:16.97 and delta=-61:52:57.8. In 2007 June we obtained I, R and V images, where the counterpart seems to be double indicating the presence of an interloper at ~1.4 arcsec NW. After separating the contribution of KY TrA we calculate I=21.47+-0.09, R=22.3+-0.1 and V=23.6+-0.1. Similar brightness in the I band was measured in May 2004 and June 2010. Variability was analyzed from series of images taken in 2004, spanning 0.6 h, and in two blocks of 6 h during 2007. We find that the target is not variable in any dataset above the error levels ~0.07 mags. The presence of the interloper might explain the non-detection of the classic ellipsoidal modulation; our data indicates that it contributes around half of the total flux, which would make a variation <0.15 mags not detectable. A single spectrum ob...

  1. Proton and hydride affinities in excited states: magnitude reversals in proton and hydride affinities between the lowest singlet and triplet states of annulenyl and benzannulenyl anions and cations

    DEFF Research Database (Denmark)

    Rosenberg, Martin; Ottosson, Henrik; Kilså, Kristine

    2010-01-01

    Aromaticity has importance for proton and hydride affinities in the singlet ground state (S(0)) of annulenyl anions and cations so that, e.g., cyclopentadiene is an acidic hydrocarbon. For the lowest pipi* excited triplet state (T(1)), Baird's rule concludes that annulenes with 4n pi-electrons ar......Aromaticity has importance for proton and hydride affinities in the singlet ground state (S(0)) of annulenyl anions and cations so that, e.g., cyclopentadiene is an acidic hydrocarbon. For the lowest pipi* excited triplet state (T(1)), Baird's rule concludes that annulenes with 4n pi......-electrons are aromatic and those with 4n+2 pi-electrons are antiaromatic, opposite to Huckel's rule for aromaticity in S(0). Our hypothesis is now that the relative magnitudes of proton and hydride affinities of annulenyl anions and cations reverts systematically as one goes from S(0) to T(1) as a result of the opposite...... electron counting rules for aromaticity in the two states. Using quantum chemical calculations at the G3(MP2)//(U)B3LYP/6-311+G(d,p) level we have examined the validity of this hypothesis for eight proton and eight hydride addition reactions of anions and cations, respectively, of annulenyl...

  2. Characterization of cardiac quiescence from retrospective cardiac computed tomography using a correlation-based phase-to-phase deviation measure

    Energy Technology Data Exchange (ETDEWEB)

    Wick, Carson A.; McClellan, James H. [School of Electrical and Computer Engineering, Georgia Institute of Technology, 777 Atlantic Drive Northwest, Atlanta, Georgia 30332 (United States); Arepalli, Chesnal D. [Department of Radiology, University of British Columbia, 3350-950 West 10th Avenue, Vancouver, British Columbia V5Z 4E3 (Canada); Auffermann, William F.; Henry, Travis S. [Department of Radiology and Imaging Sciences, Emory University, Division of Cardiothoracic Imaging, 1364 Clifton Road Northeast, Suite 309, Atlanta, Georgia 30322 (United States); Khosa, Faisal [Department of Radiology and Imaging Sciences, Emory University, Division of Emergency Radiology, 550 Peachtree Street Northeast, Atlanta, Georgia 30308 (United States); Coy, Adam M. [School of Medicine, Emory University, 100 Woodruff Circle, Atlanta, Georgia 30322 (United States); Tridandapani, Srini, E-mail: stridan@emory.edu [Department of Radiology and Imaging Sciences, Emory University, Winship Cancer Institute, 1701 Uppergate Drive Northeast, Suite 5018, Atlanta, Georgia 30322 and School of Electrical and Computer Engineering, Georgia Institute of Technology, 777 Atlantic Drive Northwest, Atlanta, Georgia 30332 (United States)

    2015-02-15

    Purpose: Accurate knowledge of cardiac quiescence is crucial to the performance of many cardiac imaging modalities, including computed tomography coronary angiography (CTCA). To accurately quantify quiescence, a method for detecting the quiescent periods of the heart from retrospective cardiac computed tomography (CT) using a correlation-based, phase-to-phase deviation measure was developed. Methods: Retrospective cardiac CT data were obtained from 20 patients (11 male, 9 female, 33–74 yr) and the left main, left anterior descending, left circumflex, right coronary artery (RCA), and interventricular septum (IVS) were segmented for each phase using a semiautomated technique. Cardiac motion of individual coronary vessels as well as the IVS was calculated using phase-to-phase deviation. As an easily identifiable feature, the IVS was analyzed to assess how well it predicts vessel quiescence. Finally, the diagnostic quality of the reconstructed volumes from the quiescent phases determined using the deviation measure from the vessels in aggregate and the IVS was compared to that from quiescent phases calculated by the CT scanner. Three board-certified radiologists, fellowship-trained in cardiothoracic imaging, graded the diagnostic quality of the reconstructions using a Likert response format: 1 = excellent, 2 = good, 3 = adequate, 4 = nondiagnostic. Results: Systolic and diastolic quiescent periods were identified for each subject from the vessel motion calculated using the phase-to-phase deviation measure. The motion of the IVS was found to be similar to the aggregate vessel (AGG) motion. The diagnostic quality of the coronary vessels for the quiescent phases calculated from the aggregate vessel (P{sub AGG}) and IVS (P{sub IV} {sub S}) deviation signal using the proposed methods was comparable to the quiescent phases calculated by the CT scanner (P{sub CT}). The one exception was the RCA, which improved for P{sub AGG} for 18 of the 20 subjects when compared to P

  3. Survival or revival: long-term preservation induces a reversible viable but non-culturable state in methane-oxidizing bacteria.

    Directory of Open Access Journals (Sweden)

    Sven Hoefman

    Full Text Available Knowledge on long-term preservation of micro-organisms is limited and research in the field is scarce despite its importance for microbial biodiversity and biotechnological innovation. Preservation of fastidious organisms such as methane-oxidizing bacteria (MOB has proven difficult. Most MOB do not survive lyophilization and only some can be cryopreserved successfully for short periods. A large-scale study was designed for a diverse set of MOB applying fifteen cryopreservation or lyophilization conditions. After three, six and twelve months of preservation, the viability (via live-dead flow cytometry and culturability (via most-probable number analysis and plating of the cells were assessed. All strains could be cryopreserved without a significant loss in culturability using 1% trehalose in 10-fold diluted TSB (TT as preservation medium and 5% DMSO as cryoprotectant. Several other cryopreservation and lyophilization conditions, all of which involved the use of TT medium, also allowed successful preservation but showed a considerable loss in culturability. We demonstrate here that most of these non-culturables survived preservation according to viability assessment indicating that preservation induces a viable but non-culturable (VBNC state in a significant fraction of cells. Since this state is reversible, these findings have major implications shifting the emphasis from survival to revival of cells in a preservation protocol. We showed that MOB cells could be significantly resuscitated from the VBNC state using the TT preservation medium.

  4. Expression of hsp70 and ferritin in embryos of the copepod Acartia tonsa (Dana) during transition between subitaneous and quiescent state

    DEFF Research Database (Denmark)

    Nilsson, Birgitte; Jepsen, Per Meyer; Rewitz, Kim Furbo

    2014-01-01

    Subitaneous eggs of the neritic calanoid copepod Acartia tonsa (Dana) are capable of entering a resting state called quiescence to overcome adverse environmental conditions. Although physiological changes associated with this transition have been described, the molecular mechanisms are thus far...

  5. Reversible Computing

    Science.gov (United States)

    1980-02-01

    will have been introduced. 9. Reversible celular autemata We shall assume the reader to have some familiarity with the concept of cel- lular...10003 Mr. Kin B. Thcmpson 1 copy Technical Director Information Systems Divisia.i Naval Research Laboratory (OP-91T) Technical Information Division

  6. Michaelis-Menten Kinetics in Transient State: Proposal for Reversible Inhibition Model and its Application on Enzymatic Hydrolysis of Disaccharides

    Directory of Open Access Journals (Sweden)

    André Rosa Martins

    2014-11-01

    Full Text Available The enzymatic processes according Michaelis-Menten kinetics have been studied from various approaches to describe the inhibition state. Proposals for inhibition were compared from a generic process, where kinetic constants have received unitary values, and the numeric value of the concentration of substrate was ten (10 times higher than the numerical value of the concentration of enzyme. For each inhibition model proposed, numerical solutions were obtained from nonlinear system of ordinary differential equations, generating results presents by graphs showing the variation of the enzyme and enzyme complexes, also the variation of substrate and product of the reaction. Also, was designed a model with performance, indicating similar behavior to that seen in the Michaelis-Menten kinetics, where complex of reaction is rapidly formed and throughout the process, tends to decay to zero. Thus, in this new proposed model, the effect of inhibition starts at zero and, throughout the process, tends to the nominal value of the initial enzyme concentration. Such responses have proved to be valid for different values of enzyme concentration and process time, showing robustness. The proposed model was applied to the hydrolysis of disaccharides, providing a setting with conservation of mass of the model at the end of the process regarding the responses of the carbohydrate concentration.

  7. Reversible Communicating Processes

    Directory of Open Access Journals (Sweden)

    Geoffrey Brown

    2016-02-01

    Full Text Available Reversible distributed programs have the ability to abort unproductive computation paths and backtrack, while unwinding communication that occurred in the aborted paths. While it is natural to assume that reversibility implies full state recovery (as with traditional roll-back recovery protocols, an interesting alternative is to separate backtracking from local state recovery. For example, such a model could be used to create complex transactions out of nested compensable transactions where a programmer-supplied compensation defines the work required to "unwind" a transaction. Reversible distributed computing has received considerable theoretical attention, but little reduction to practice; the few published implementations of languages supporting reversibility depend upon a high degree of central control. The objective of this paper is to demonstrate that a practical reversible distributed language can be efficiently implemented in a fully distributed manner. We discuss such a language, supporting CSP-style synchronous communication, embedded in Scala. While this language provided the motivation for the work described in this paper, our focus is upon the distributed implementation. In particular, we demonstrate that a "high-level" semantic model can be implemented using a simple point-to-point protocol.

  8. Reversal magnetization dependence with the Cr and Fe oxidation states in YFe1-xCrxO3 (0≤x≤1) perovskites

    Science.gov (United States)

    Fabian, F. A.; Pedra, P. P.; Moura, K. O.; Duque, J. G. S.; Meneses, C. T.

    2016-06-01

    In this work, we have carried out a detailed study of the magnetic and structural properties of YFe1-xCrxO3 (0≤x≤1) samples with orthorhombic structure obtained by co-precipitation method. Analysis of X-ray diffraction data using Rietveld refinement show that all samples present an orthorhombic crystal system with space group Pnma. Besides, we have observed a reduction of unit cell volume with increasing of the Cr concentration. SEM images show the formation of grains of micrometer order. X-ray Absorption near edge spectroscopy (XANES) measurements show a shift of absorption edge which can be indicate there is (i) different oxidation states to Fe and Cr ions and/or (ii) a changing in the point symmetry of Fe and Cr ions to the compounds. The magnetization measurements indicate a continuous decreasing of the magnetic transition temperature as function of chromium doping. The reversal magnetization effect was observed to concentrations around x=0.5. Besides, the deviation of the Curie-Weiss law and a weak ferromagnetic behavior observed at room temperature in the M vs H curves can be attributed to the strong magnetic interactions between the transition metals with different oxidation states.

  9. The reversal of fortunes: trends in county mortality and cross-county mortality disparities in the United States.

    Directory of Open Access Journals (Sweden)

    Majid Ezzati

    2008-04-01

    Full Text Available Counties are the smallest unit for which mortality data are routinely available, allowing consistent and comparable long-term analysis of trends in health disparities. Average life expectancy has steadily increased in the United States but there is limited information on long-term mortality trends in the US counties This study aimed to investigate trends in county mortality and cross-county mortality disparities, including the contributions of specific diseases to county level mortality trends.We used mortality statistics (from the National Center for Health Statistics [NCHS] and population (from the US Census to estimate sex-specific life expectancy for US counties for every year between 1961 and 1999. Data for analyses in subsequent years were not provided to us by the NCHS. We calculated different metrics of cross-county mortality disparity, and also grouped counties on the basis of whether their mortality changed favorably or unfavorably relative to the national average. We estimated the probability of death from specific diseases for counties with above- or below-average mortality performance. We simulated the effect of cross-county migration on each county's life expectancy using a time-based simulation model. Between 1961 and 1999, the standard deviation (SD of life expectancy across US counties was at its lowest in 1983, at 1.9 and 1.4 y for men and women, respectively. Cross-county life expectancy SD increased to 2.3 and 1.7 y in 1999. Between 1961 and 1983 no counties had a statistically significant increase in mortality; the major cause of mortality decline for both sexes was reduction in cardiovascular mortality. From 1983 to 1999, life expectancy declined significantly in 11 counties for men (by 1.3 y and in 180 counties for women (by 1.3 y; another 48 (men and 783 (women counties had nonsignificant life expectancy decline. Life expectancy decline in both sexes was caused by increased mortality from lung cancer, chronic obstructive

  10. Phosphorylation of eIF2α Is a Translational Control Mechanism Regulating Muscle Stem Cell Quiescence and Self-Renewal.

    Science.gov (United States)

    Zismanov, Victoria; Chichkov, Victor; Colangelo, Veronica; Jamet, Solène; Wang, Shuo; Syme, Alasdair; Koromilas, Antonis E; Crist, Colin

    2016-01-01

    Regeneration of adult tissues depends on somatic stem cells that remain quiescent yet are primed to enter a differentiation program. The molecular pathways that prevent activation of these cells are not well understood. Using mouse skeletal muscle stem cells as a model, we show that a general repression of translation, mediated by the phosphorylation of translation initiation factor eIF2α at serine 51 (P-eIF2α), is required to maintain the quiescent state. Skeletal muscle stem cells unable to phosphorylate eIF2α exit quiescence, activate the myogenic program, and differentiate, but do not self-renew. P-eIF2α ensures in part the robust translational silencing of accumulating mRNAs that is needed to prevent the activation of muscle stem cells. Additionally, P-eIF2α-dependent translation of mRNAs regulated by upstream open reading frames (uORFs) contributes to the molecular signature of stemness. Pharmacological inhibition of eIF2α dephosphorylation enhances skeletal muscle stem cell self-renewal and regenerative capacity.

  11. Ancient Magnetic Reversals: Clues to the Geodynamo.

    Science.gov (United States)

    Hoffman, Kenneth A.

    1988-01-01

    Discusses the question posed by some that the earth's magnetic field may reverse. States that rocks magnetized by ancient fields may offer clues to the underlying reversal mechanism in the earth's core. (TW)

  12. Regulation of human ornithine decarboxylase expression following prolonged quiescence: role for the c-Myc/Max protein complex.

    Science.gov (United States)

    Peña, A; Wu, S; Hickok, N J; Soprano, D R; Soprano, K J

    1995-02-01

    WI-38 cells can remain quiescent for long periods of time and still be induced to reenter the cell cycle by the addition of fresh serum. However, the longer these cells remain growth arrested, the more time they require to enter S phase. This prolongation of the prereplicative phase has been localized to a point early in G1, after the induction of "immediate early" G1 genes such as c-fos and c-jun but before maximal expression of "early" G1 genes such as ornithine decarboxylase (ODC). Understanding the molecular basis for ODC mRNA induction can therefore provide information about the molecular events which regulate the progression of cells out of long-term quiescence into G1 and subsequently into DNA synthesis. Studies utilizing electrophoretic mobility shift assays (EMSA) of nuclear extracts from short- and long-term quiescent WI-38 cells identified a region of the human ODC promoter at -491 bp to -474 bp which exhibited a protein binding pattern that correlated with the temporal pattern of ODC mRNA expression. The presence of a CACGTG element within this fragment, studies with antibodies against c-Myc and Max, the use of purified recombinant c-Myc protein in the mobility shift assay, and antisense studies suggest that these proteins can specifically bind this portion of the human ODC promoter in a manner consistent with growth-associated modulation of the expression of ODC and other early G1 genes following prolonged quiescence. These studies suggest a role for the c-Myc/Max protein complex in regulating events involved in the progression of cells out of long-term quiescence into G1 and subsequently into S.

  13. XMM-Newton observations of the black hole X-ray transient XTE J1650-500 in quiescence

    CERN Document Server

    Homan, J; Kong, A; Miller, J M; Rossi, S; Belloni, T; Lewin, W H G; Homan, Jeroen; Wijnands, Rudy; Kong, Albert; Miller, Jon M.; Rossi, Sabrina; Belloni, Tomaso; Lewin, Walter H.G.

    2006-01-01

    We report the result of an XMM-Newton observation of the black-hole X-ray transient XTE J1650-500 in quiescence. The source was not detected and we set upper limits on the 0.5-10 keV luminosity of 0.9e31-1.0e31 erg/s (for a newly derived distance of 2.6 kpc). These limits are in line with the quiescent luminosities of black-hole X-ray binaries with similar orbital periods (~7-8 hr)

  14. Intrabasin paleoearthquake and quiescence correlation of the late Holocene Dead Sea

    Science.gov (United States)

    Kagan, Elisa; Stein, Mordechai; Agnon, Amotz; Neumann, Frank

    2011-04-01

    A comprehensive multisite paleoseismic archive of the late Holocene Dead Sea basin (past 2500 years) is established by constructing two age-depth chronological models of two sedimentary sections exposed at the retreating shores of the modern Dead Sea. Two new paleoseismic study sites studied are the Ein Feshkha Nature Reserve outcrop located at the northern part of the basin and close to an active underwater transverse fault and the east Ze'elim Gully outcrop at the southern part of the basin. Age-depth regression models are calculated for these sections based on atmospheric radiocarbon ages of short-lived organic debris calibrated with a Bayesian model. The uncertainties on individual model ages are smaller than 100 years. The new chronological records are compared to a laminae-counting study of the Ein Gedi core (Migowski et al., 2004) located at the central Dead Sea basin. The Ein Feshkha outcrop yielded the largest number of seismites in the studied time interval (n = 52), while lower numbers of seismites are recovered from the Ze'elim outcrop and Ein Gedi core (n = 15 and 36, respectively). The seismites show no strong dependence on the limnological-sedimentological conditions in the particular sampling sites (they coappear in both shallow and deep water environments and in different sedimentary facies). During time intervals when the chronologies are comparable it appears that the number of seismites is significantly larger in the northern part of the basin (Ein Gedi and Ein Feshkha). Seismic quiescence intervals are apparent at all three sites from 2nd-4th century A.D. and at 500-150 B.C. at Ze'elim and Ein Gedi. Several synchronous seismites appear in all sections (termed here the intrabasin seismites (IBS)). Among them: 1927, 1293, 1202/1212, 749, 551, 419, and 33 A.D. and 31 and mid-2nd century B.C. The recurrence time of the IBS from the 2nd century B.C. to the 14th century A.D. is ˜200 years, compared with ˜100 years for all earthquakes. On a diagram

  15. Evidence for Time-Reversal Symmetry Breaking of the Superconducting State near Twin-Boundary Interfaces in FeSe Revealed by Scanning Tunneling Spectroscopy

    Science.gov (United States)

    Watashige, T.; Tsutsumi, Y.; Hanaguri, T.; Kohsaka, Y.; Kasahara, S.; Furusaki, A.; Sigrist, M.; Meingast, C.; Wolf, T.; Löhneysen, H. v.; Shibauchi, T.; Matsuda, Y.

    2015-07-01

    Junctions and interfaces consisting of unconventional superconductors provide an excellent experimental playground to study exotic phenomena related to the phase of the order parameter. Not only does the complex structure of unconventional order parameters have an impact on the Josephson effects, but it also may profoundly alter the quasiparticle excitation spectrum near a junction. Here, by using spectroscopic-imaging scanning tunneling microscopy, we visualize the spatial evolution of the LDOS near twin boundaries (TBs) of the nodal superconductor FeSe. The π /2 rotation of the crystallographic orientation across the TB twists the structure of the unconventional order parameter, which may, in principle, bring about a zero-energy LDOS peak at the TB. The LDOS at the TB observed in our study, in contrast, does not exhibit any signature of a zero-energy peak, and an apparent gap amplitude remains finite all the way across the TB. The low-energy quasiparticle excitations associated with the gap nodes are affected by the TB over a distance more than an order of magnitude larger than the coherence length ξa b. The modification of the low-energy states is even more prominent in the region between two neighboring TBs separated by a distance ≈7 ξa b . In this region, the spectral weight near the Fermi level (≈±0.2 meV ) due to the nodal quasiparticle spectrum is almost completely removed. These behaviors suggest that the TB induces a fully gapped state, invoking a possible twist of the order parameter structure, which breaks time-reversal symmetry.

  16. Reversible logic gate using adiabatic superconducting devices

    Science.gov (United States)

    Takeuchi, N.; Yamanashi, Y.; Yoshikawa, N.

    2014-09-01

    Reversible computing has been studied since Rolf Landauer advanced the argument that has come to be known as Landauer's principle. This principle states that there is no minimum energy dissipation for logic operations in reversible computing, because it is not accompanied by reductions in information entropy. However, until now, no practical reversible logic gates have been demonstrated. One of the problems is that reversible logic gates must be built by using extremely energy-efficient logic devices. Another difficulty is that reversible logic gates must be both logically and physically reversible. Here we propose the first practical reversible logic gate using adiabatic superconducting devices and experimentally demonstrate the logical and physical reversibility of the gate. Additionally, we estimate the energy dissipation of the gate, and discuss the minimum energy dissipation required for reversible logic operations. It is expected that the results of this study will enable reversible computing to move from the theoretical stage into practical usage.

  17. Quiescence of adult oligodendrocyte precursor cells requires thyroid hormone and hypoxia to activate Runx1.

    Science.gov (United States)

    Tokumoto, Yasuhito; Tamaki, Shinpei; Kabe, Yasuaki; Takubo, Keiyo; Suematsu, Makoto

    2017-04-21

    The adult mammalian central nervous system (CNS) contains a population of slowly dividing oligodendrocyte precursor cells (OPCs), i.e., adult OPCs, which supply new oligodendrocytes throughout the life of animal. While adult OPCs develop from rapidly dividing perinatal OPCs, the mechanisms underlying their quiescence remain unknown. Here, we show that perinatal rodent OPCs cultured with thyroid hormone (TH) under hypoxia become quiescent and acquire adult OPCs-like characteristics. The cyclin-dependent kinase inhibitor p15/INK4b plays crucial roles in the TH-dependent cell cycle deceleration in OPCs under hypoxia. Klf9 is a direct target of TH-dependent signaling. Under hypoxic conditions, hypoxia-inducible factors mediates runt-related transcription factor 1 activity to induce G1 arrest in OPCs through enhancing TH-dependent p15/INK4b expression. As adult OPCs display phenotypes of adult somatic stem cells in the CNS, the current results shed light on environmental requirements for the quiescence of adult somatic stem cells during their development from actively proliferating stem/progenitor cells.

  18. Onset of Quiescence Following p53 Mediated Down-Regulation of H2AX in Normal Cells

    Science.gov (United States)

    Inase, Aki; Shinohe, Keitaro; Yoshioka, Yoshiko; Shikanai, Mima; Ichijima, Yosuke; Unno, Junya; Mizutani, Shuki; Tsuchiya, Naoto; Hippo, Yoshitaka; Nakagama, Hitoshi; Masutani, Mitsuko; Teraoka, Hirobumi; Yoshioka, Ken-ichi

    2011-01-01

    Normal cells, both in vivo and in vitro, become quiescent after serial cell proliferation. During this process, cells can develop immortality with genomic instability, although the mechanisms by which this is regulated are unclear. Here, we show that a growth-arrested cellular status is produced by the down-regulation of histone H2AX in normal cells. Normal mouse embryonic fibroblast cells preserve an H2AX diminished quiescent status through p53 regulation and stable-diploidy maintenance. However, such quiescence is abrogated under continuous growth stimulation, inducing DNA replication stress. Because DNA replication stress-associated lesions are cryptogenic and capable of mediating chromosome-bridge formation and cytokinesis failure, this results in tetraploidization. Arf/p53 module-mutation is induced during tetraploidization with the resulting H2AX recovery and immortality acquisition. Thus, although cellular homeostasis is preserved under quiescence with stable diploidy, tetraploidization induced under growth stimulation disrupts the homeostasis and triggers immortality acquisition. PMID:21858116

  19. Onset of quiescence following p53 mediated down-regulation of H2AX in normal cells.

    Directory of Open Access Journals (Sweden)

    Yuko Atsumi

    Full Text Available Normal cells, both in vivo and in vitro, become quiescent after serial cell proliferation. During this process, cells can develop immortality with genomic instability, although the mechanisms by which this is regulated are unclear. Here, we show that a growth-arrested cellular status is produced by the down-regulation of histone H2AX in normal cells. Normal mouse embryonic fibroblast cells preserve an H2AX diminished quiescent status through p53 regulation and stable-diploidy maintenance. However, such quiescence is abrogated under continuous growth stimulation, inducing DNA replication stress. Because DNA replication stress-associated lesions are cryptogenic and capable of mediating chromosome-bridge formation and cytokinesis failure, this results in tetraploidization. Arf/p53 module-mutation is induced during tetraploidization with the resulting H2AX recovery and immortality acquisition. Thus, although cellular homeostasis is preserved under quiescence with stable diploidy, tetraploidization induced under growth stimulation disrupts the homeostasis and triggers immortality acquisition.

  20. The X-ray Spectra of Black Hole X-ray Novae in Quiescence as Measured by Chandra

    CERN Document Server

    Kong, A K H; García, M R; Murray, S S; Barret, D

    2002-01-01

    We present Chandra observations of black hole X-ray novae V404 Cyg, A0620-00, GRO J1655-40 and XTE J1550-564 in quiescence. Their quiescent spectra can be well fitted by a power-law model with slope $\\alpha \\sim 2$. While a coronal (Raymond-Smith) model is also a statistically acceptable representation of the spectra, the best fit temperatures of these models is $\\sim 5$ times higher than that seen in active stellar coronae. These four spectra of quiescent X-ray novae are all consistent with that expected for accretion via an advection-dominated accretion flow (ADAF) and inconsistent with that expected from a stellar corona. This evidence for continued accretion in quiescence further strengthens the case for the existence of event horizons in black holes. Both A0620-00 and GRO J1655-40 were fainter than in previous observations, while V404 Cyg was more luminous and varied by a factor of 2 in a few ksec. A reanalysis of the X-ray data for XTE J1550-564 shows that (like V404 Cyg and A0620-00) its luminosity exc...

  1. Transcriptional repression of Bmp2 by p21(Waf1/Cip1) links quiescence to neural stem cell maintenance.

    Science.gov (United States)

    Porlan, Eva; Morante-Redolat, José Manuel; Marqués-Torrejón, María Ángeles; Andreu-Agulló, Celia; Carneiro, Carmen; Gómez-Ibarlucea, Esther; Soto, Atenea; Vidal, Anxo; Ferrón, Sacri R; Fariñas, Isabel

    2013-11-01

    Relative quiescence and self renewal are defining features of adult stem cells, but their potential coordination remains unclear. Subependymal neural stem cells (NSCs) lacking cyclin-dependent kinase (CDK) inhibitor (CKI) 1a (p21) exhibit rapid expansion that is followed by their permanent loss later in life. Here we demonstrate that transcription of the gene encoding bone morphogenetic protein 2 (Bmp2) in NSCs is under the direct negative control of p21 through actions that are independent of CDK. Loss of p21 in NSCs results in increased levels of secreted BMP2, which induce premature terminal differentiation of multipotent NSCs into mature non-neurogenic astrocytes in an autocrine and/or paracrine manner. We also show that the cell-nonautonomous p21-null phenotype is modulated by the Noggin-rich environment of the subependymal niche. The dual function that we describe here provides a physiological example of combined cell-autonomous and cell-nonautonomous functions of p21 with implications in self renewal, linking the relative quiescence of adult stem cells to their longevity and potentiality.

  2. Chandra and Swift observations of the quasi-persistent neutron star transient EXO 0748-676 in quiescence

    CERN Document Server

    Degenaar, N; Wolff, M T; Ray, P S; Wood, K S; Homan, J; Lewin, W H G; Jonker, P G; Cackett, E M; Miller, J M; Brown, E F

    2008-01-01

    The quasi-persistent neutron star X-ray transient and eclipsing binary EXO 0748-676 recently returned to quiescence following an accretion outburst that lasted more than 24 years. We report on 2 Chandra and 5 Swift observations performed approximately one to two months after the transition from outburst to quiescence. The Chandra observations detect the source at a bolometric thermal luminosity of ~9.8E33 (d/7.4 kpc) erg/s. The spectrum is composed of a soft, thermal component that fits to a neutron star atmosphere model with kT^inf~0.11 keV, combined with a hard powerlaw tail that contributes ~20% of the total 0.5-10 keV quiescent flux. Several Swift observations were obtained 1-2 weeks before the Chandra observations and another series was taken approximately 2 weeks thereafter. The combined Chandra/Swift data set reveals a relatively hot and luminous quiescent system with a temperature of kT^inf~0.11-0.13 keV and a bolometric thermal luminosity that slightly decreased from ~1.6E34 to ~8.3E33 (d/7.4 kpc) er...

  3. Reversible Statistics

    DEFF Research Database (Denmark)

    Tryggestad, Kjell

    2004-01-01

    The study aims is to describe how the inclusion and exclusion of materials and calculative devices construct the boundaries and distinctions between statistical facts and artifacts in economics. My methodological approach is inspired by John Graunt's (1667) Political arithmetic and more recent work...... within constructivism and the field of Science and Technology Studies (STS). The result of this approach is here termed reversible statistics, reconstructing the findings of a statistical study within economics in three different ways. It is argued that all three accounts are quite normal, albeit...... in different ways. The presence and absence of diverse materials, both natural and political, is what distinguishes them from each other. Arguments are presented for a more symmetric relation between the scientific statistical text and the reader. I will argue that a more symmetric relation can be achieved...

  4. Cotopaxi volcano's unrest and eruptive activity in 2015: mild awakening after 73 years of quiescence

    Science.gov (United States)

    Hidalgo, Silvana; Bernard, Benjamin; Battaglia, Jean; Gaunt, Elizabeth; Barrington, Charlotte; Andrade, Daniel; Ramón, Patricio; Arellano, Santiago; Yepes, Hugo; Proaño, Antonio; Almeida, Stefanie; Sierra, Daniel; Dinger, Florian; Kelly, Peter; Parra, René; Bobrowski, Nicole; Galle, Bo; Almeida, Marco; Mothes, Patricia; Alvarado, Alexandra

    2016-04-01

    Cotopaxi volcano (5,897 m) is located 50 km south of Quito, the capital of Ecuador. The most dangerous hazards of this volcano are the devastating lahars that can be generated by the melting of its ice cap during pyroclastic flow-forming eruptions. The first seismic station was installed in 1976. Cotopaxi has been monitored by the Instituto Geofísico (Escuela Politécnica Nacional) since 1983. Presently the monitoring network is comprised of 11 broadband and 5 short period seismometers, 4 scanning DOAS, 1 infrared and 5 visible cameras, 7 DGPS, 5 tiltmeters, 11 AFM (lahar detectors) and a network of ashmeters. Due to the recent unrest, the monitoring of the volcano has been complemented by campaign airborne Multi-GAS and thermal IR measurements and ground-based mobile DOAS and stationary solar FTIR. After 73 years of quiescence, the first sign of unrest was a progressive increase in the amplitude of transient seismic events in April 2015. Since May 20, an increase in SO2 emissions from ˜500 t/d to ˜3 kt/day was detected followed by the appearance of seismic tremor on June 4. Both SO2 emissions of up to 5 kt/day and seismic tremor were observed until August 14 when a swarm of volcano-tectonic earthquakes preceded the first phreatic explosions. These explosions produced ash and gas columns reaching up to 9 km above the crater. The ash fall produced by the opening phase covered over 500 km2 with a submillimetric deposit corresponding to a mass of 1.65E+8 kg (VEI 1). During this period of explosions, SO2 emission rates up to 24 kt/day were observed, the highest thus far. The ash was dominantly hydrothermally altered and oxidized lithic fragments, hydrothermal minerals (alunite, gypsum), free crystals of plagioclase and pyroxenes, and little juvenile material. Unrest continued after August 14, with three episodes of ash emission. However, the intensity of ash fallout, average seismic amplitude, and SO2 emissions during each successive episode progressively decreased

  5. Reversible hysteresis loop tuning

    Science.gov (United States)

    Berger, A.; Binek, Ch.; Margulies, D. T.; Moser, A.; Fullerton, E. E.

    2006-02-01

    We utilize antiferromagnetically coupled bilayer structures to magnetically tune hysteresis loop properties. Key element of this approach is the non-overlapping switching field distribution of the two magnetic layers that make up the system: a hard magnetic CoPtCrB layer (HL) and a soft magnetic CoCr layer (SL). Both layers are coupled antiferromagnetically through an only 0.6-nm-thick Ru interlayer. The non-overlapping switching field distribution allows the measurement of magnetization reversal in the SL at low fields while keeping the magnetization state of the HL unperturbed. Applying an appropriate high field or high field sequence changes the magnetic state of the HL, which then influences the SL magnetization reversal due to the interlayer coupling. In this way, the position and shape of the SL hysteresis loop can be changed or tuned in a fully reversible and highly effective manner. Here, we study specifically how the SL hysteresis loop characteristics change as we move the HL through an entire high field hysteresis loop sequence.

  6. The black hole candidate XTE J1752-223 towards and in quiescence: optical and simultaneous X-ray-radio observations

    NARCIS (Netherlands)

    Ratti, E.M.; Jonker, P.G.; Miller-Jones, J.C.A.; Torres, M.A.P.; Homan, J.; Markoff, S.; Tomsick, J.; Kaaret, P.; Wijnands, R.; Gallo, E.; Özel, F.; Steeghs, D.T.H.; Fender, R.P.

    2012-01-01

    We present optical, X-ray and radio observations of the black hole transient (BHT) XTE J1752−223 towards and in quiescence. Optical photometry shows that the quiescent magnitude of XTE J1752−223 is fainter than 24.4 mag in the i′ band. A comparison with measurements of the source during its 2009-201

  7. WI-38 cell long-term quiescence model system: a valuable tool to study molecular events that regulate growth.

    Science.gov (United States)

    Soprano, K J

    1994-04-01

    A number of cell culture model systems have been used to study the regulation of cell cycle progression at the molecular level. In this paper we describe the WI-38 cell long-term quiescence model system. By modulating the length of time that WI-38 cells are density arrested, it is possible to proportionately alter the length of the prereplicative or G-1 phase which the cell traverses after growth factor stimulation in preparation for entry into DNA synthesis. Through studies aimed at understanding the cause and molecular nature of the prolongation of the prereplicative phase, we have determined that gene expression plays an important role in establishing growth factor "competence" and that once the cell becomes "competent" there is a defined order to the molecular events that follow during the remainder of G-1. More specifically, we have determined that the prolongation represents a delay in the ability of long term quiescent cells to become fully "competent" to respond to growth factors which regulate progression through G-1 into S. This prolongation appears to occur as a result of changes during long term quiescence in the ability of immediate early G-1 specific genes (such as c-myc) to activate the expression of early G-1 specific genes (such as ornithine decarboxylase). While ODC is the first and thus far only growth associated gene identified as a target of c-myc (and the Myc/Max protein complex), it is likely that further studies in this model system will reveal other early G-1 growth regulatory genes. We anticipate that future follow-up studies in this model system will provide additional valuable information about the function of growth-regulatory genes in controlling growth factor responsiveness and cell cycle progression.

  8. US-Japan workshop on field-reversed configurations with steady-state high-temperature fusion plasmas and the 11th US-Japan workshop on compact toroids

    Energy Technology Data Exchange (ETDEWEB)

    Barnes, D.C.; Fernandez, J.C.; Rej, D.J. (comps.)

    1990-05-01

    The US-Japan Workshop on Field-Reversed Configurations with Steady-State High-Temperature Fusion Plasma and the 11th US-Japan Workshop on Compact Toroids were held at Los Alamos National Laboratory, Los Alamos, New Mexico on November 7--9, 1989. These proceedings contain the papers presented at the workshops as submitted by the authors. These papers have been indexed separately.

  9. US-Japan Workshop on Field-Reversed Configurations with Steady-State High-Temperature Fusion Plasmas and the 11th US-Japan Workshop on Compact Toroids

    Science.gov (United States)

    Barnes, D. C.; Fernandez, J. C.; Rej, D. J.

    1990-05-01

    The U.S.-Japan Workshop on Field-Reversed Configurations with Steady-State High-Temperature Fusion Plasma and the 11th U.S.-Japan Workshop on Compact Toroids were held at Los Alamos National Laboratory, Los Alamos, New Mexico on November 7 to 9, 1989. These proceedings contain the papers presented at the workshops as submitted by the authors. These papers have been indexed separately.

  10. Managing Reverse Logistics or Reversing Logistics Management?

    OpenAIRE

    Brito, Marisa

    2004-01-01

    textabstractIn the past, supply chains were busy fine-tuning the logistics from raw material to the end customer. Today an increasing flow of products is going back in the chain. Thus, companies have to manage reverse logistics as well.This thesis contributes to a better understanding of reverse logistics. The thesis brings insights on reverse logistics decision-making and it lays down theoretical principles for reverse logistics as a research field.In particular it puts together a framework ...

  11. Predicting Quiescence: The Dependence of Specific Star Formation Rate on Galaxy Size and Central Density at 0.5

    CERN Document Server

    Whitaker, Katherine E; van Dokkum, Pieter G; Franx, Marijn; van der Wel, Arjen; Brammer, Gabriel; Forster-Schreiber, Natascha M; Giavalisco, Mauro; Labbe, Ivo; Momcheva, Ivelina G; Nelson, Erica J; Skelton, Rosalind

    2016-01-01

    In this paper, we investigate the relationship between star formation and structure, using a mass-complete sample of 27,893 galaxies at 0.50.5 dex from z~2 to z~0.7. Neither a compact galaxy size nor a high n are sufficient to assess the likelihood of quiescence for the average galaxy; rather, it is the combination of these two parameters together with stellar mass that results in a unique quenching threshold in central density or velocity.

  12. Dispersive Tidal Plume Modeling of Brine Discharge from Reverse Osmosis (RO) Desalination System, Coral Bay, St. John, USVI using Finite Segment Steady-state Response Matrix (SSRM)

    Science.gov (United States)

    Yoon, J.; Shahvari, A.

    2011-12-01

    This characterization and modeling study of dispersive tidal plume of brine discharge from reverse osmosis (RO) desalination system is a part of the Environmental Assessment (EA) for a new reverse osmosis system in the Coral Bay, St. John, USVI (US Virgin Island). Main foci are on developing the tidal longitudinal (perpendicular to the shoreline) and lateral (parallel to the shoreline) dispersion coefficients and subsequently characterize dispersion and mixing characterization of the negatively buoyant brine discharge plume from the proposed reverse osmosis plant to evaluate the level of salinity variations in the nearshore mixing plume in regard to existing coral reef ecosystem. An in situ dye study was conducted by a marine biologist for this purpose to estimate brine discharge plume dispersion coefficients under oscillatory tidal transport and fate flux for current and proposed plant configuration. Additional tidal and surface runoff hydrologic data, bathymetric data and brine discharge characteristics in the vicinity of the brine discharge location are reflected in this study. With estimated dispersion coefficients, eighteen brine discharge scenarios were evaluated to model anticipated dispersive characteristics under varying operational conditions and ambient tidal current conditions for average measured salinity of 33.27 PSU in loco as well as a standard 35 PSU for typical nearshore water salinity variations. Modeling results indicated that the dispersive tidal plume of design brine discharge from reverse osmosis (RO) desalination system at a discharge of 150,000 gpd would raise salinity no higher than 0.0123 PSU in receiving nearshore estuarine water (Maximum concentration at the segment 3 = 33.2822 PSU at Δt = 12 hrs and 24 hrs in diurnal tidal cycle under when the brine discharge with Base+25% concentration, 81.25 PSU at brine discharge rate of 0.0066 m3/sec, and with a minimum direct overland flow efflux at 0.003 m3/sec - this is a "worst-case" operating

  13. PTPN13 and β-Catenin Regulate the Quiescence of Hematopoietic Stem Cells and Their Interaction with the Bone Marrow Niche

    Directory of Open Access Journals (Sweden)

    Guillermo López-Ruano

    2015-10-01

    Full Text Available The regulation of hematopoietic stem cells (HSCs depends on the integration of the multiple signals received from the bone marrow niche. We show the relevance of the protein tyrosine phosphatase PTPN13 and β-catenin as intracellular signaling molecules to control HSCs adhesiveness, cell cycling, and quiescence. Lethally irradiated mice transplanted with Lin– bone marrow cells in which PTPN13 or β-catenin had been silenced showed a significant increase of long-term (LT and short-term (ST HSCs. A decrease in cycling cells was also found, together with an increase in quiescence. The decreased expression of PTPN13 or β-catenin was linked to the upregulation of several genes coding for integrins and several cadherins, explaining the higher cell adhesiveness. Our data are consistent with the notion that the levels of PTPN13 and β-catenin must be strictly regulated by extracellular signaling to regulate HSC attachment to the niche and the balance between proliferation and quiescence.

  14. Diapause and post-diapause quiescence demonstrated in overwintering Harmonia axyeidis (Coleoptera: Coccinellidae) in northwestern Europe

    NARCIS (Netherlands)

    Raak-van den Berg, C.L.; Jong, de P.W.; Hemerik, L.; Lenteren, van J.C.

    2013-01-01

    The Asian ladybird Harmonia axyridis (Pallas) (Coleoptera: Coccinellidae) is regarded as an invasive species in many parts of the world. In a previous study we hypothesised that H. axyridis enters diapause at the end of October and then shifts to a quiescent state in December in northwestern Europe.

  15. Diapause and post-diapause quiescence demonstrated in overwintering Harmonia axyeidis (Coleoptera: Coccinellidae) in northwestern Europe

    NARCIS (Netherlands)

    Raak-van den Berg, C.L.; Jong, de P.W.; Hemerik, L.; Lenteren, van J.C.

    2013-01-01

    The Asian ladybird Harmonia axyridis (Pallas) (Coleoptera: Coccinellidae) is regarded as an invasive species in many parts of the world. In a previous study we hypothesised that H. axyridis enters diapause at the end of October and then shifts to a quiescent state in December in northwestern Europe.

  16. Phase-resolved spectroscopy of the helium dwarf nova `SN 2003aw' in quiescence

    NARCIS (Netherlands)

    Roelofs, G.H.A.; Groot, P.J.; Marsh, T.R.; Steeghs, D.; Nelemans, G.

    2006-01-01

    High time resolution spectroscopic observations of the ultracompact helium dwarf nova `SN2003aw' in its quiescent state at V~ 20.5 reveal its orbital period at 2027.8 +/- 0.5 s or 33.80 min. Together with the photometric `superhump' period of 2041.5 +/- 0.5 s, this implies a mass ratio q~ 0.036. We

  17. A virulent Wolbachia infection decreases the viability of the dengue vector Aedes aegypti during periods of embryonic quiescence.

    Directory of Open Access Journals (Sweden)

    Conor J McMeniman

    Full Text Available A new approach for dengue control has been proposed that relies on life-shortening strains of the obligate intracellular bacterium Wolbachia pipientis to modify mosquito population age structure and reduce pathogen transmission. Previously we reported the stable transinfection of the major dengue vector Aedes aegypti with a life-shortening Wolbachia strain (wMelPop-CLA from the vinegar fly Drosophila melanogaster. Here, we report a further characterization of the phenotypic effects of this virulent Wolbachia infection on several life-history traits of Ae. aegypti. Minor costs of wMelPop-CLA infection for pre-imaginal survivorship, development and adult size were found. However, we discovered that the wMelPop-CLA infection dramatically decreased the viability of desiccated Ae. aegypti eggs over time. Similarly, the reproductive fitness of wMelPop-CLA infected Ae. aegypti females declined with age. These results reveal a general pattern associated with wMelPop-CLA induced pathogenesis in this mosquito species, where host fitness costs increase during aging of both immature and adult life-history stages. In addition to influencing the invasion dynamics of this particular Wolbachia strain, we suggest that the negative impact of wMelPop-CLA on embryonic quiescence may have applied utility as a tool to reduce mosquito population size in regions with pronounced dry seasons or in regions that experience cool winters.

  18. The X-ray properties of the black hole transient MAXI J1659-152 in quiescence

    CERN Document Server

    Homan, Jeroen; Jonker, Peter G; Russell, David M; Gallo, Elena; Kuulkers, Erik; Rea, Nanda; Altamirano, Diego

    2013-01-01

    We present new Chandra X-ray observations of the transient black hole X-ray binary MAXI J1659-152 in quiescence. These observations were made more than one year after the end of the source's 2010-2011 outburst. We detect the source at a 0.5-10 keV flux of 2.8(8)e-15 erg/cm^2/s, which corresponds to a luminosity of ~1.2e31 (d/ 6 kpc)^2 erg/s. This level, while being the lowest at which the source has been detected, is within factors of ~2 of the levels seen at the end of the initial decay of the outburst and soon after a major reflare of the source. The quiescent luminosity of MAXI J1659-152, which is the shortest-orbital-period black hole X-ray binary (~2.4 hr), is lower than that of neutron-star X-ray binaries with similar periods. However, it is higher than the quiescent luminosities found for black hole X-ray binaries with orbital periods ~2-4 times longer. This could imply that a minimum quiescent luminosity may exist for black hole X-ray binaries, around orbital periods of ~5-10 hr, as predicted by binar...

  19. Characterizing X-ray and Radio emission in the Black Hole X-Ray Binary V404 Cygni during Quiescence

    CERN Document Server

    Rana, Vikram; Corbel, Stephane; Tomsick, John A; Chakrabarty, Deepto; Walton, Dominic J; Barret, Didier; Boggs, Steven E; Christensen, Finn E; Craig, William; Fuerst, Felix; Gandhi, Poshak; Grefenstette, Brian W; Hailey, Charles; Harrison, Fiona A; Madsen, Kristin K; Rahoui, Farid; Stern, Daniel; Tendulkar, Shriharsh; Zhang, William W

    2015-01-01

    We present results from multi-wavelength simultaneous X-ray and radio observations of the black hole X-ray binary V404 Cyg in quiescence. Our coverage with NuSTAR provides the very first opportunity to study the X-ray spectrum of V404 Cyg at energies above 10 keV. The unabsorbed broad-band (0.3-30 keV) quiescent luminosity of the source is 8.9$\\times$10$^{32}$ erg s$^{-1}$ for a distance of 2.4 kpc. The source shows clear variability on short time scales in radio, soft X-ray and hard X-ray bands in the form of multiple flares. The broad-band X-ray spectra obtained from XMM-Newton and NuSTAR can be characterized with a power-law model having photon index {\\Gamma}=2.13$\\pm$0.07 (90% confidence errors); however, residuals at high energies indicate spectral curvature significant at a 3{\\sigma} confidence level with e-folding energy of the cutoff to be 19$^{+19}_{-7}$ keV. Such curvature can be explained using synchrotron emission from the base of a jet outflow. Radio observations using the JVLA reveal that the sp...

  20. The accretion dynamics of EX Lupi in quiescence:The star, the spot, and the accretion column

    CERN Document Server

    Sicilia-Aguilar, A; Roccatagliata, V; Cameron, A C; Kospal, A; Henning, Th; Abraham, P; Sipos, N

    2015-01-01

    EX Lupi is a young star, prototype of EXor variables. Its spectrum is very rich in emission lines, including many metallic lines. It has been also proposed to have a close companion. We use the metallic emission lines to study the accretion structures and to test the companion hypothesis. We analyse 54 spectra taken in 5 years of quiescence time. We study the line profile variability and the radial velocity of the metallic emission lines. We use the velocity signatures of different species with various excitation conditions and their time dependency to track the dynamics associated to accretion. We observe periodic velocity variations in the line components consistent with rotational modulation. The modulation is stronger for lines with higher excitation potentials. We propose that the narrow line components are produced in the post-shock region, while the broad components originate in the more extended, pre-shock material. All the emission lines suffer velocity modulation due to the rotation of the star. The...

  1. Further X-ray observations of EXO 0748-676 in quiescence: evidence for a cooling neutron star crust

    Science.gov (United States)

    Degenaar, N.; Wolff, M. T.; Ray, P. S.; Wood, K. S.; Homan, J.; Lewin, W. H. G.; Jonker, P. G.; Cackett, E. M.; Miller, J. M.; Brown, E. F.; Wijnands, R.

    2011-04-01

    In late 2008, the quasi-persistent neutron star X-ray transient and eclipsing binary EXO 0748-676 started a transition from outburst to quiescence, after it actively accreted for more than 24 yr. In a previous work, we discussed Chandra and Swift observations obtained during the first 5 months of this transition. Here, we report on further X-ray observations of EXO 0748-676, extending the quiescent monitoring to 1.6 yr. Chandra and XMM-Newton data reveal quiescent X-ray spectra composed of a soft, thermal component that is well fitted by a neutron star atmosphere model. An additional hard power-law tail is detected that changes non-monotonically over time, contributing between 4 and 20 per cent to the total unabsorbed 0.5-10 keV flux. The combined set of Chandra, XMM-Newton and Swift data reveals that the thermal bolometric luminosity fades from ˜ 1 × 1034 to 6 × 1033 (D/7.4 kpc)2 erg s -1, whereas the inferred neutron star effective temperature decreases from ˜124 to 109 eV. We interpret the observed decay as cooling of the neutron star crust and show that the fractional quiescent temperature change of EXO 0748-676 is markedly smaller than observed for three other neutron star X-ray binaries that underwent prolonged accretion outbursts.

  2. A virulent Wolbachia infection decreases the viability of the dengue vector Aedes aegypti during periods of embryonic quiescence.

    Science.gov (United States)

    McMeniman, Conor J; O'Neill, Scott L

    2010-07-13

    A new approach for dengue control has been proposed that relies on life-shortening strains of the obligate intracellular bacterium Wolbachia pipientis to modify mosquito population age structure and reduce pathogen transmission. Previously we reported the stable transinfection of the major dengue vector Aedes aegypti with a life-shortening Wolbachia strain (wMelPop-CLA) from the vinegar fly Drosophila melanogaster. Here, we report a further characterization of the phenotypic effects of this virulent Wolbachia infection on several life-history traits of Ae. aegypti. Minor costs of wMelPop-CLA infection for pre-imaginal survivorship, development and adult size were found. However, we discovered that the wMelPop-CLA infection dramatically decreased the viability of desiccated Ae. aegypti eggs over time. Similarly, the reproductive fitness of wMelPop-CLA infected Ae. aegypti females declined with age. These results reveal a general pattern associated with wMelPop-CLA induced pathogenesis in this mosquito species, where host fitness costs increase during aging of both immature and adult life-history stages. In addition to influencing the invasion dynamics of this particular Wolbachia strain, we suggest that the negative impact of wMelPop-CLA on embryonic quiescence may have applied utility as a tool to reduce mosquito population size in regions with pronounced dry seasons or in regions that experience cool winters.

  3. Evidence for 830 years of seismic quiescence from palaeoseismology, archaeoseismology and historical seismicity along the Dead Sea fault in Syria

    Science.gov (United States)

    Meghraoui, Mustapha; Gomez, Francisco; Sbeinati, Reda; Van der Woerd, Jerome; Mouty, Michel; Darkal, Abdul Nasser; Radwan, Youssef; Layyous, Ihsan; Al Najjar, Haithem; Darawcheh, Ryad; Hijazi, Fouad; Al-Ghazzi, Riad; Barazangi, Muawia

    2003-05-01

    The long historical record of earthquakes, the physical effects on ancient building structures and the palaeoseismology provide a unique opportunity for an interdisciplinary tectonic analysis along a major plate boundary and a realistic evaluation of the seismic hazard assessment in the Middle East. We demonstrate with micro-topographic surveys and trenching that the Dead Sea fault (DSF) offsets left-laterally by 13.6±0.2 m a repeatedly fractured ancient Roman aqueduct (older than AD 70 and younger than AD 30). Carbon-14 dating of faulted young alluvial deposits documents the occurrence of three large earthquakes in the past 2000 years between AD 100 and 750, between AD 700 and 1030 and between AD 990 and 1210. Our study provides the timing of late Holocene earthquakes and constrains the 6.9±0.1 mm/yr slip rate of the Dead Sea transform fault in northwestern Syria along the Missyaf segment. The antepenultimate and most recent faulting events may be correlated with the AD 115 and AD 1170 large earthquakes for which we estimate Mw=7.3-7.5. The ˜830 yr of seismic quiescence along the Missyaf fault segment implies that a large earthquake is overdue and may result in a major catastrophe to the population centres of Syria and Lebanon.

  4. alpha2beta1 integrin controls association of Rac with the membrane and triggers quiescence of endothelial cells.

    Science.gov (United States)

    Cailleteau, Laurence; Estrach, Soline; Thyss, Raphael; Boyer, Laurent; Doye, Anne; Domange, Barbara; Johnsson, Nils; Rubinstein, Eric; Boucheix, Claude; Ebrahimian, Teni; Silvestre, Jean-Sebastien; Lemichez, Emmanuel; Meneguzzi, Guerrino; Mettouchi, Amel

    2010-07-15

    Integrin receptors and their extracellular matrix ligands provide cues to cell proliferation, survival, differentiation and migration. Here, we show that alpha2beta1 integrin, when ligated to the basement membrane component laminin-1, triggers a proliferation arrest in primary endothelial cells. Indeed, in the presence of strong growth signals supplied by growth factors and fibronectin, alpha2beta1 engagement alters assembly of mature focal adhesions by alpha5beta1 and leads to impairment of downstream signaling and cell-cycle arrest in the G1 phase. Although the capacity of alpha5beta1 to signal for GTP loading of Rac is preserved, the joint engagement of alpha2beta1 interferes with membrane anchorage of Rac. Adapting the 'split-ubiquitin' sensor to screen for membrane-proximal alpha2 integrin partners, we identified the CD9 tetraspanin and further establish its requirement for destabilization of focal adhesions, control of Rac subcellular localization and growth arrest induced by alpha2beta1 integrin. Altogether, our data establish that alpha2beta1 integrin controls endothelial cell commitment towards quiescence by triggering a CD9-dependent dominant signaling.

  5. The quasi-persistent neutron star soft X-ray transient 1M 1716-315 in quiescence

    CERN Document Server

    Jonker, P G; Wachter, S

    2007-01-01

    We report on our analysis of a 20 ksec Chandra X-ray observation of the quasi-persistent neutron star soft X-ray transient (SXT) 1M1716-315 in quiescence. Only one source was detected in the HEAO-I error region. Its luminosity is 1.6E32-1.3E33 erg s-1. In this the range is dominated by the uncertainty in the source distance. The source spectrum is well described by an absorbed soft spectrum, e.g. a neutron star atmosphere or black body model. No optical or near-infrared counterpart is present at the location of the X-ray source, down to a magnitude limit of I> 23.5 and K_s> 19.5. The positional evidence, the soft X-ray spectrum together with the optical and near-infrared non-detections provide strong evidence that this source is the quiescent neutron star SXT. The source is 10-100 times too bright in X-rays in order to be explained by stellar coronal X-ray emission. Together with the interstellar extinction measured in outburst and estimates for the source distance, the reported optical and near-infrared limi...

  6. Increased radial glia quiescence, decreased reactivation upon injury and unaltered neuroblast behavior underlie decreased neurogenesis in the aging zebrafish telencephalon.

    Science.gov (United States)

    Edelmann, Kathrin; Glashauser, Lena; Sprungala, Susanne; Hesl, Birgit; Fritschle, Maike; Ninkovic, Jovica; Godinho, Leanne; Chapouton, Prisca

    2013-09-01

    The zebrafish has recently become a source of new data on the mechanisms of neural stem cell (NSC) maintenance and ongoing neurogenesis in adult brains. In this vertebrate, neurogenesis occurs at high levels in all ventricular regions of the brain, and brain injuries recover successfully, owing to the recruitment of radial glia, which function as NSCs. This new vertebrate model of adult neurogenesis is thus advancing our knowledge of the molecular cues in use for the activation of NSCs and fate of their progeny. Because the regenerative potential of somatic stem cells generally weakens with increasing age, it is important to assess the extent to which zebrafish NSC potential decreases or remains unaltered with age. We found that neurogenesis in the ventricular zone, in the olfactory bulb, and in a newly identified parenchymal zone of the telencephalon indeed declines as the fish ages and that oligodendrogenesis also declines. In the ventricular zone, the radial glial cell population remains largely unaltered morphologically but enters less frequently into the cell cycle and hence produces fewer neuroblasts. The neuroblasts themselves do not change their behavior with age and produce the same number of postmitotic neurons. Thus, decreased neurogenesis in the physiologically aging zebrafish brain is correlated with an increasing quiescence of radial glia. After injuries, radial glia in aged brains are reactivated, and the percentage of cell cycle entry is increased in the radial glia population. However, this reaction is far less pronounced than in younger animals, pointing to irreversible changes in aging zebrafish radial glia.

  7. Further X-ray observations of EXO 0748-676 in quiescence: evidence for a cooling neutron star crust

    CERN Document Server

    Degenaar, N; Ray, P S; Wood, K S; Homan, J; Lewin, W H G; Jonker, P G; Cackett, E M; Miller, J M; Brown, E F; Wijnands, R

    2010-01-01

    In late 2008, the quasi-persistent neutron star X-ray transient and eclipsing binary EXO 0748-676 started a transition from outburst to quiescence, after it had been actively accreting for more than 24 years. In a previous work, we discussed Chandra and Swift observations obtained during the first five months after this transition. Here, we report on further X-ray observations of EXO 0748-676, extending the quiescent monitoring to 1.6 years. Chandra and XMM-Newton data reveal quiescent X-ray spectra composed of a soft, thermal component that is well-fitted by a neutron star atmosphere model. An additional hard powerlaw tail is detected that changes non-monotonically over time, contributing between 4 and 20 percent to the total unabsorbed 0.5-10 keV flux. The combined set of Chandra, XMM-Newton and Swift data reveals that the thermal bolometric luminosity fades from ~1E34 to 6E33 (d/7.4 kpc)^2 erg/s, whereas the inferred neutron star effective temperature decreases from ~124 to 109 eV. We interpret the observe...

  8. The mass, radius, distance and cooling of the neutron star in EXO 0748-676 in quiescence with XMM-Newton

    Science.gov (United States)

    Cheng, Zheng; Mendez, Mariano; Costantini, Elisa; Diaz Trigo, Maria

    2016-07-01

    We present the spectral analysis of four XMM-Newton observations of the neutron-star low-mass X-ray binary EXO 0748-676 in quiescence, taken between 2009 and 2013. We fit the spectra with an absorbed neutron-star atmosphere model, without the need for a high-energy (power-law) component, with a 95 per cent confidence upper limit of 1 per cent to the contribution of the power law to the total flux of the source in the 0.2-10.0 keV band. We find a significant emission line at around 0.5 keV in the spectra of the three CCD cameras on board XMM-Newton of all four observations; the line, which we tentatively identify as Lyα emission from NVII, is moderately broad, σ ≈ 0.17 keV, and contributes ˜10-14 per cent of the total flux in the 0.2-10 keV band. The temperature of the neutron star in EXO 0748-676 has decreased significantly compared to the previous XMM-Newton observation, with the cooling curve being consistent with either an exponential decay plus a constant, a power law or a broken power-law. We fitted the spectra with a neutron-star atmosphere model that takes into account the observed peak flux of photospheric radius expansion (PRE) bursts to constrain the neutron-star mass, radius and distance self-consistently. Using this model we carried out MCMC simulations assuming a uniform prior for the inclination angle of the system (which accounts for anisotropy in the emission at the peak of the bursts) and for the hydrogen fraction of the fuel during the PRE bursts. We find that M _{ns} = 1.87 ^{+0.69}_{-0.32} M⊙, R_{ns} = 8.5^{+3.2}_{-1.3} km and D = 5.4^{+2.4}_{-1.2} kpc (99% confidence level), which is inconsistent with quark-bearing equations of state for this neutron star.

  9. Reverse polarization in conjugated heterocycle polythiophene

    Institute of Scientific and Technical Information of China (English)

    王鹿霞; 刘德胜; 张大成; 解士杰; 韩圣浩; 梅良模

    2005-01-01

    Reverse polarization in polythiophene under an applied electric field has been studied in the framework of the tightbinding model. It is found that the applied electronic field has a great influence on the excited states of polythiophene.The effect of the heteroatoms on the polarization has been calculated and analysed carefully. It is indicated that a reverse polarization of biexcitons in polythiophene will be observed more easily. The heteroatoms increase this reversed polarization strength apparently.

  10. Reverse polarization in conjugated heterocycle polythiophene

    Science.gov (United States)

    Wang, Lu-Xia; Liu, De-Sheng; Zhang, Da-Cheng; Xie, Shi-Jie; Han, Sheng-Hao; Mei, Liang-Mo

    2005-01-01

    Reverse polarization in polythiophene under an applied electric field has been studied in the framework of the tight-binding model. It is found that the applied electronic field has a great influence on the excited states of polythiophene. The effect of the heteroatoms on the polarization has been calculated and analysed carefully. It is indicated that a reverse polarization of biexcitons in polythiophene will be observed more easily. The heteroatoms increase this reversed polarization strength apparently.

  11. Managing Reverse Logistics or Reversing Logistics Management?

    NARCIS (Netherlands)

    M.P. de Brito (Marisa)

    2004-01-01

    textabstractIn the past, supply chains were busy fine-tuning the logistics from raw material to the end customer. Today an increasing flow of products is going back in the chain. Thus, companies have to manage reverse logistics as well.This thesis contributes to a better understanding of reverse

  12. Managing Reverse Logistics or Reversing Logistics Management?

    NARCIS (Netherlands)

    M.P. de Brito (Marisa)

    2004-01-01

    textabstractIn the past, supply chains were busy fine-tuning the logistics from raw material to the end customer. Today an increasing flow of products is going back in the chain. Thus, companies have to manage reverse logistics as well.This thesis contributes to a better understanding of reverse log

  13. MDM2 turnover and expression of ATRX determine the choice between quiescence and senescence in response to CDK4 inhibition.

    Science.gov (United States)

    Kovatcheva, Marta; Liu, David D; Dickson, Mark A; Klein, Mary E; O'Connor, Rachael; Wilder, Fatima O; Socci, Nicholas D; Tap, William D; Schwartz, Gary K; Singer, Samuel; Crago, Aimee M; Koff, Andrew

    2015-04-10

    CDK4 inhibitors (CDK4i) earned Breakthrough Therapy Designation from the FDA last year and are entering phase III clinical trials in several cancers. However, not all tumors respond favorably to these drugs. CDK4 activity is critical for progression through G1 phase and into the mitotic cell cycle. Inhibiting this kinase induces Rb-positive cells to exit the cell cycle into either a quiescent or senescent state. In this report, using well-differentiated and dedifferentiated liposarcoma (WD/DDLS) cell lines, we show that the proteolytic turnover of MDM2 is required for CDK4i-induced senescence. Failure to reduce MDM2 does not prevent CDK4i-induced withdrawal from the cell cycle but the cells remain in a reversible quiescent state. Reducing MDM2 in these cells drives them into the more stable senescent state. CDK4i-induced senescence associated with loss of MDM2 is also observed in some breast cancer, lung cancer and glioma cell lines indicating that this is not limited to WD/DDLS cells in which MDM2 is overexpressed or in cells that contain wild type p53. MDM2 turnover depends on its E3 ligase activity and expression of ATRX. Interestingly, in seven patients the changes in MDM2 expression were correlated with outcome. These insights identify MDM2 and ATRX as new regulators controlling geroconversion, the process by which quiescent cells become senescent, and this insight may be exploited to improve the activity of CDK4i in cancer therapy.

  14. Reversible Thermoset Adhesives

    Science.gov (United States)

    Mac Murray, Benjamin C. (Inventor); Tong, Tat H. (Inventor); Hreha, Richard D. (Inventor)

    2016-01-01

    Embodiments of a reversible thermoset adhesive formed by incorporating thermally-reversible cross-linking units and a method for making the reversible thermoset adhesive are provided. One approach to formulating reversible thermoset adhesives includes incorporating dienes, such as furans, and dienophiles, such as maleimides, into a polymer network as reversible covalent cross-links using Diels Alder cross-link formation between the diene and dienophile. The chemical components may be selected based on their compatibility with adhesive chemistry as well as their ability to undergo controlled, reversible cross-linking chemistry.

  15. Reverse logistics - a framework

    OpenAIRE

    Brito, Marisa; Dekker, Rommert

    2002-01-01

    textabstractIn this paper we define and compare Reverse Logistics definitions. We start by giving an understanding framework of Reverse Logistics: the why-what-how. By this means, we put in context the driving forces for Reverse Logistics, a typology of return reasons, a classification of products, processes and actors. In addition we provide a decision framework for Reverse Logistics and we present it according to long, medium and short term decisions, i.e. strategic-tactic-operational decis...

  16. Reverse cholesterol transport revisited

    Institute of Scientific and Technical Information of China (English)

    Astrid; E; van; der; Velde

    2010-01-01

    Reverse cholesterol transport was originally described as the high-density lipoprotein-mediated cholesterol flux from the periphery via the hepatobiliary tract to the intestinal lumen, leading to fecal excretion. Since the introduction of reverse cholesterol transport in the 1970s, this pathway has been intensively investigated. In this topic highlight, the classical reverse cholesterol transport concepts are discussed and the subject reverse cholesterol transport is revisited.

  17. The milliarcsecond-scale jet of PKS 0735+178 during quiescence

    CERN Document Server

    Agudo, I; Gabuzda, D C; Gómez, J L; Jorstad, S G; Marscher, A P

    2006-01-01

    We present polarimetric 5 GHz to 43 GHz VLBI observations of the BL Lacertae object PKS 0735+178, spanning March 1996 to May 2000. Comparison with previous and later observations suggests that the overall kinematic and structural properties of the jet are greatly influenced by its activity. Time intervals of enhanced activity, as reported before 1993 and after 2000 by other studies, are followed by highly superluminal motion along a rectilinear jet. In contrast the less active state in which we performed our observations, shows subluminal or slow superluminal jet features propagating through a twisted jet with two sharp bends of about 90 deg. within the innermost three-milliarcsecond jet structure. Proper motion estimates from the data presented here allow us to constrain the jet viewing angle to values < 9 deg., and the bulk Lorentz factor to be between 2 and 4.

  18. Reverse logistics - a framework

    NARCIS (Netherlands)

    M.P. de Brito (Marisa); R. Dekker (Rommert)

    2002-01-01

    textabstractIn this paper we define and compare Reverse Logistics definitions. We start by giving an understanding framework of Reverse Logistics: the why-what-how. By this means, we put in context the driving forces for Reverse Logistics, a typology of return reasons, a classification of product

  19. Are all reversible computations tidy?

    CERN Document Server

    Maroney, O J E

    2004-01-01

    It has long been known that to minimise the heat emitted by a deterministic computer during it's operation it is necessary to make the computation act in a logically reversible manner\\cite{Lan61}. Such logically reversible operations require a number of auxiliary bits to be stored, maintaining a history of the computation, and which allows the initial state to be reconstructed by running the computation in reverse. These auxiliary bits are wasteful of resources and may require a dissipation of energy for them to be reused. A simple procedure due to Bennett\\cite{Ben73} allows these auxiliary bits to be "tidied", without dissipating energy, on a classical computer. All reversible classical computations can be made tidy in this way. However, this procedure depends upon a classical operation ("cloning") that cannot be generalised to quantum computers\\cite{WZ82}. Quantum computations must be logically reversible, and therefore produce auxiliary qbits during their operation. We show that there are classes of quantu...

  20. A Nuclear Role for miR-9 and Argonaute Proteins in Balancing Quiescent and Activated Neural Stem Cell States

    Directory of Open Access Journals (Sweden)

    Shauna Katz

    2016-10-01

    Full Text Available Throughout life, adult neural stem cells (NSCs produce new neurons and glia that contribute to crucial brain functions. Quiescence is an essential protective feature of adult NSCs; however, the establishment and maintenance of this state remain poorly understood. We demonstrate that in the adult zebrafish pallium, the brain-enriched miR-9 is expressed exclusively in a subset of quiescent NSCs, highlighting a heterogeneity within these cells, and is necessary to maintain NSC quiescence. Strikingly, miR-9, along with Argonaute proteins (Agos, is localized to the nucleus of quiescent NSCs, and manipulating their nuclear/cytoplasmic ratio impacts quiescence. Mechanistically, miR-9 permits efficient Notch signaling to promote quiescence, and we identify the RISC protein TNRC6 as a mediator of miR-9/Agos nuclear localization in vivo. We propose a conserved non-canonical role for nuclear miR-9/Agos in controlling the balance between NSC quiescence and activation, a key step in maintaining adult germinal pools.

  1. The decrease in histone methyltransferase EZH2 in response to fluid shear stress alters endothelial gene expression and promotes quiescence.

    Science.gov (United States)

    Maleszewska, Monika; Vanchin, Byambasuren; Harmsen, Martin C; Krenning, Guido

    2016-01-01

    High uniform fluid shear stress (FSS) is atheroprotective and preserves the endothelial phenotype and function through activation of downstream mediators such as MAPK7 (Erk5). Endothelial cells respond to FSS thanks to mechanotransduction. However, how the resulting signaling is integrated and resolved at the epigenetic level remains elusive. We hypothesized that Polycomb methyltransferase EZH2 is involved in the effects of FSS in human endothelial cells. We showed that FSS decreases the expression of the Polycomb methyltransferase EZH2. Despite simultaneous activation of MAPK7, MAPK7 pathway does not directly influence the transcription of EZH2. Interestingly though, the knockdown of EZH2 activates the protective MAPK7 signaling in endothelial cells, even in the absence of FSS. To understand the influence of the FSS-decreased expression of EZH2 on endothelial transcriptome, we performed RNA-seq and differential gene expression analysis. We identified candidate groups of genes dependent on both EZH2 and FSS. Among those, Gene Ontology overrepresentation analysis revealed highly significant enrichment of the cell cycle-related genes, suggesting changes in proliferation. Indeed, the depletion of EZH2 strongly inhibited endothelial proliferation, indicating cell cycle arrest. The concomitant decrease in CCNA expression suggests the transition of endothelial cells into a quiescent phenotype. Further bioinformatical analysis suggested TXNIP as a possible mediator between EZH2 and cell cycle-related gene network. Our data show that EZH2 is a FSS-responsive gene. Decreased EZH2 levels enhance the activation of the atheroprotective MAPK7 signaling. Decrease in EZH2 under FSS mediates the decrease in the expression of the network of cell cycle-related genes, which allows the cells to enter quiescence. EZH2 is therefore important for the protective effects of FSS in endothelium.

  2. Reversed phase liquid chromatography hyphenated to continuous flow-extractive desorption electrospray ionization-mass spectrometry for analysis and charge state manipulation of undigested proteins.

    Science.gov (United States)

    Li, Li; Yang, Samuel H; Vidova, Veronika; Rice, Elisa M; Wijeratne, Aruna B; Havlíček, Vladimír; Schug, Kevin A

    2015-01-01

    The application of continuous flow-extractive desorption electrospray ionization (CF-EDESI), an ambient ionization source demonstrated previously for use with intact protein analysis, is expanded here for the coupling of reversed phase protein separations to mass spectrometry. This configuration allows the introduction of charging additives to enhance detection without affecting the chromatographic separation mechanism. Two demonstrations of the advantages of CF-EDESI are presented in this work. First, a proof-of- principle is presented to demonstrate the applicability of hyphenation of liquid chromatography (LC) to CF- EDESI. LC-CF-EDESI-MS has good sensitivity compared to LC-electrospray ionization (ESI)-mass spectrometry. Second, the supercharging mechanism investigated in CF-EDESI provides an insight into a highly debated supercharging process in ESI. The results indicate that the mechanism of protein charging seen in HPLC-CF-EDESI is different from supercharging phenomena in conventional ESI. The surface tension mechanism and binding mechanism may both contribute to protein supercharging in ESI.

  3. Vital signs: trends in use of long-acting reversible contraception among teens aged 15-19 years seeking contraceptive services—United States, 2005-2013.

    Science.gov (United States)

    Romero, Lisa; Pazol, Karen; Warner, Lee; Gavin, Lorrie; Moskosky, Susan; Besera, Ghenet; Loyola Briceno, Ana Carolina; Jatlaoui, Tara; Barfield, Wanda

    2015-04-10

    Nationally, the use of long-acting reversible contraception (LARC), specifically intrauterine devices (IUDs) and implants, by teens remains low, despite their effectiveness, safety, and ease of use. To examine patterns in use of LARC among females aged 15-19 years seeking contraceptive services, CDC and the U.S. Department of Health and Human Services' Office of Population Affairs analyzed 2005-2013 data from the Title X National Family Planning Program. Title X serves approximately 1 million teens each year and provides family planning and related preventive health services for low-income persons. Use of LARC among teens seeking contraceptive services at Title X service sites increased from 0.4% in 2005 to 7.1% in 2013 (p-value for trend contraceptive services in 2013, 17,349 (2.8%) used IUDs, and 26,347 (4.3%) used implants. Use of LARC was higher among teens aged 18-19 years (7.6%) versus 15-17 years (6.5%) (pcontraception at Title X service sites have increased use of these methods. Health centers that provide quality contraceptive services can facilitate use of LARC among teens seeking contraception. Strategies to address provider barriers to offering LARC include: 1) educating providers that LARC is safe for teens; 2) training providers on LARC insertion and a client-centered counseling approach that includes discussing the most effective contraceptive methods first; and 3) providing contraception at reduced or no cost to the client.

  4. HST Observations of IP Pegasi in Quiescence The Pre-Eclipse Spectrum

    CERN Document Server

    Hoard, D W; Eracleous, M; Horne, K; Misselt, K A; Shafter, A W; Szkody, P; Wood, J H; Baptista, Raymundo; Eracleous, Michael; Horne, Keith; Shafter, Allen W.; Szkody, Paula; Wood, Janet H.

    1997-01-01

    We present time-resolved HST UV spectroscopy and ground-based optical photometry of the dwarf nova IP Peg in a quiescent state. The observations were obtained prior to an eclipse, when the bright spot caused by the impact of the accretion stream with the edge of the disk dominates the light output. The optical light curve is strongly correlated with the UV spectrophotometric flux curve. An emission-like feature near 1820 A in the UV spectrum is likely to be a manifestation of the ``Fe II curtain.'' Composite spectra constructed from the peaks and troughs of flickers in the light curve show substantial differences. The spectrum of the flickers is not adequately modelled by a simple blackbody, suggesting that a more sophisticated model is appropriate. We perform a cross-correlation analysis of the variability in spectrophotometric flux curves of the UV continuum and prominent UV emission lines (C II 1335, Si IV 1400, C IV 1550). The continuum and lines are not correlated, suggesting that they are produced separ...

  5. Phase-resolved spectroscopy of the helium dwarf nova 'SN 2003aw' in quiescence

    CERN Document Server

    Roelofs, G; Marsh, T; Steeghs, D; Nelemans, G

    2006-01-01

    High time resolution spectroscopic observations of the ultra-compact helium dwarf nova 'SN 2003aw' in its quiescent state at V=20.5 reveal its orbital period at 2027.8 +/- 0.5 seconds or 33.80 minutes. Together with the photometric 'superhump' period of 2041.5 +/- 0.5 seconds, this implies a mass ratio q of 0.036. We compare both the average and time-resolved spectra of 'SN 2003aw' and SDSS J124058.03-015919.2. Both show a DB white dwarf spectrum plus an optically thin, helium-dominated accretion disc. 'SN 2003aw' distinguishes itself from the SDSS source by its strong calcium H & K emission lines, suggesting higher abundances of heavy metals than the SDSS source. The silicon and iron emission lines observed in the SDSS source are about twice as strong in 'SN 2003aw'. The peculiar 'double bright spot' accretion disc feature seen in the SDSS source is also present in time-resolved spectra of 'SN 2003aw', albeit much weaker.

  6. X-ray and UV observations of the dwarf nova VW Hyi in quiescence

    CERN Document Server

    Pandel, D; Howell, S B; Pandel, Dirk; Cordova, France A.; Howell, Steve B.

    2003-01-01

    We present an analysis of X-ray and ultra-violet data of the dwarf nova VW Hyi that were obtained with XMM-Newton during the quiescent state. The X-ray spectrum indicates the presence of an optically thin plasma in the boundary layer that cools as it settles onto the white dwarf. The plasma has a continuous temperature distribution that is well described by a power-law or a cooling flow model with a maximum temperature of 6-8 keV. We estimate from the X-ray spectrum a boundary layer luminosity of 8*10^30 erg/s, which is only 20 per cent of the disk luminosity. The rate of accretion onto the white dwarf is 5*10^-12 solar masses per year, about half of the rate in the disk. From the high-resolution X-ray spectra, we estimate that the X-ray emitting part of the boundary layer is rotating with a velocity of 540 km/s, which is close the rotation velocity of the white dwarf but significantly smaller than the Keplerian velocity. We detect a 60-s quasi-periodic oscillation of the X-ray flux that is likely due to the ...

  7. X-ray/optical observations of A0535+26/HDE 245770 in quiescence

    CERN Document Server

    Orlandini, M; Campana, S; Del Sordo, S; De Martino, D; Frontera, F; Guarnieri, A; Israel, G; Masetti, N; Palazzi, E; Piccioni, A; Santangelo, A; Stella, L

    2004-01-01

    We present the result of three BeppoSAX observations of the X-ray binary pulsar A0535+26 in its quiescent state. The source is quite well detected up to 200 keV (6 sigma detection in the stronger observation). No Iron line is detected in the MECS data (3 sigma upper limit on its equivalent width of 150 eV). There is evidence of a soft excess below 2 keV. Pulsation is detected in all energy bands up to 10 keV, with a pulsed fraction of ~ 0.5, not varying with energy. There is a marginal detection (4 sigma) of a cyclotron resonance feature (CRF) at 118 +/- 20 keV in the PDS spectrum. During the BeppoSAX observations HDE 245770, the optical counterpart to A0535+26, was monitored spectroscopically and photometrically. These observations show that the Halpha and Hbeta lines previously observed in absorption returned in emission, indicating that the Be disk formed again. The presence of pulsation and a CRF is a clear indication that accretion onto the polar caps is occurring, and that the propeller mechanism is lea...

  8. The ETS-5 transcription factor regulates activity states in Caenorhabditis elegans by controlling satiety

    Science.gov (United States)

    Juozaityte, Vaida; Pladevall-Morera, David; Podolska, Agnieszka; Nørgaard, Steffen; Pocock, Roger

    2017-01-01

    Animal behavior is shaped through interplay among genes, the environment, and previous experience. As in mammals, satiety signals induce quiescence in Caenorhabditis elegans. Here we report that the C. elegans transcription factor ETS-5, an ortholog of mammalian FEV/Pet1, controls satiety-induced quiescence. Nutritional status has a major influence on C. elegans behavior. When foraging, food availability controls behavioral state switching between active (roaming) and sedentary (dwelling) states; however, when provided with high-quality food, C. elegans become sated and enter quiescence. We show that ETS-5 acts to promote roaming and inhibit quiescence by setting the internal “satiety quotient” through fat regulation. Acting from the ASG and BAG sensory neurons, we show that ETS-5 functions in a complex network with serotonergic and neuropeptide signaling pathways to control food-regulated behavioral state switching. Taken together, our results identify a neuronal mechanism for controlling intestinal fat stores and organismal behavioral states in C. elegans, and establish a paradigm for the elucidation of obesity-relevant mechanisms. PMID:28193866

  9. Constraining the neutron star equation of state using XMM-Newton

    NARCIS (Netherlands)

    Jonker, P.G.; Kaastra, J.S.; Méndez, M.; in 't Zand, J.J.M.

    2008-01-01

    We have identified three possible ways in which future XMM-Newton observations can provide significant constraints on the equation of state of neutron stars. First, using a long observation of the neutron star X-ray transient Cen X-4 in quiescence one can use the RGS spectrum to constrain the inters

  10. Reversible Projective Measurement in Quantum Ensembles

    CERN Document Server

    Khitrin, Anatoly; Lee, Jae-Seung

    2010-01-01

    We present experimental NMR demonstration of a scheme of reversible projective measurement, which allows extracting information on outcomes and probabilities of a projective measurement in a non-destructive way, with a minimal net effect on the quantum state of an ensemble. The scheme uses reversible dynamics and weak measurement of the intermediate state. The experimental system is an ensemble of 133Cs (S = 7/2) nuclei in a liquid-crystalline matrix.

  11. Defective quiescence entry promotes the fermentation performance of bottom-fermenting brewer's yeast.

    Science.gov (United States)

    Oomuro, Mayu; Kato, Taku; Zhou, Yan; Watanabe, Daisuke; Motoyama, Yasuo; Yamagishi, Hiromi; Akao, Takeshi; Aizawa, Masayuki

    2016-11-01

    One of the key processes in making beer is fermentation. In the fermentation process, brewer's yeast plays an essential role in both the production of ethanol and the flavor profile of beer. Therefore, the mechanism of ethanol fermentation by of brewer's yeast is attracting much attention. The high ethanol productivity of sake yeast has provided a good basis from which to investigate the factors that regulate the fermentation rates of brewer's yeast. Recent studies found that the elevated fermentation rate of sake Saccharomyces cerevisiae species is closely related to a defective transition from vegetative growth to the quiescent (G0) state. In the present study, to clarify the relationship between the fermentation rate of brewer's yeast and entry into G0, we constructed two types of mutant of the bottom-fermenting brewer's yeast Saccharomyces pastorianus Weihenstephan 34/70: a RIM15 gene disruptant that was defective in entry into G0; and a CLN3ΔPEST mutant, in which the G1 cyclin Cln3p accumulated at high levels. Both strains exhibited higher fermentation rates under high-maltose medium or high-gravity wort conditions (20° Plato) as compared with the wild-type strain. Furthermore, G1 arrest and/or G0 entry were defective in both the RIM15 disruptant and the CLN3ΔPEST mutant as compared with the wild-type strain. Taken together, these results indicate that regulation of the G0/G1 transition might govern the fermentation rate of bottom-fermenting brewer's yeast in high-gravity wort. Copyright © 2016 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

  12. Current induced magnetic flux response in frustrated three-band superconductors as a bulk probe of broken time reversal symmetry (BTRS) ground states

    Energy Technology Data Exchange (ETDEWEB)

    Yerin, Yuriy; Omelyanchouk, Alexander [Verkin Inst. for Low Temperature Physics and Engineering. 61103 Kharkiv (Ukraine); Drechsler, Stefan-Ludwig; Brink, Jeroen van den; Efremov, Dmitriy [Inst. for Theorretical Solid State Physics at the Leibniz Inst. for Solid State an Materials Research, IFW-Dresden, D-01171 Dresden (Germany)

    2016-07-01

    Within the Ginzburg-Landau formalism we provide a classification of all possible ground states (GS) of a three-band superconductor (3BSC) where either frustrated states with BTRS or a single non-BTRS GS with unconventional/conventional s-wave symmetry, respectively, exist. The necessary condition for a BTRS GS in general cannot be reduced to a ''-''sign of the product of all interband couplings (IBC) valid in the case of 3 equivalent bands with repulsive equal IBC, only. It corresponds to a maximal IBC frustration. We show that with increasing diversity of the parameter space this frustration is reduced and the regions of possible BTRS GS start to shrink. We track possible evolutions of a BTRS GS of a 3BSC based doubly-connected system in an external magnetic field. Depending on its parameters, a magnetic flux can induce various current density leaps, connected with adiabatic or non-adiabatic transitions from BTRS to non-BTRS states and vice versa. The current induced magnetic flux response of samples with a doubly-connected geometry e.g. as a thin tube provides a suitable experimental tool for the detection of BTRS GS.

  13. Combination of {sup 15}N reverse labeling and afterglow spectroscopy for assigning membrane protein spectra by magic-angle-spinning solid-state NMR: application to the multidrug resistance protein EmrE

    Energy Technology Data Exchange (ETDEWEB)

    Banigan, James R.; Gayen, Anindita; Traaseth, Nathaniel J., E-mail: traaseth@nyu.edu [New York University, Department of Chemistry (United States)

    2013-04-15

    Magic-angle-spinning (MAS) solid-state NMR spectroscopy has emerged as a viable method to characterize membrane protein structure and dynamics. Nevertheless, the spectral resolution for uniformly labeled samples is often compromised by redundancy of the primary sequence and the presence of helical secondary structure that results in substantial resonance overlap. The ability to simplify the spectrum in order to obtain unambiguous site-specific assignments is a major bottleneck for structure determination. To address this problem, we used a combination of {sup 15}N reverse labeling, afterglow spectroscopic techniques, and frequency-selective dephasing experiments that dramatically improved the ability to resolve peaks in crowded spectra. This was demonstrated using the polytopic membrane protein EmrE, an efflux pump involved in multidrug resistance. Residues preceding the {sup 15}N reverse labeled amino acid were imaged using a 3D NCOCX afterglow experiment and those following were recorded using a frequency-selective dephasing experiment. Our approach reduced the spectral congestion and provided a sensitive way to obtain chemical shift assignments for a membrane protein where no high-resolution structure is available. This MAS methodology is widely applicable to the study of other polytopic membrane proteins in functional lipid bilayer environments.

  14. Reversible cortical blindness: posterior reversible encephalopathy syndrome.

    Science.gov (United States)

    Bandyopadhyay, Sabyasachi; Mondal, Kanchan Kumar; Das, Somnath; Gupta, Anindya; Biswas, Jaya; Bhattacharyya, Subir Kumar; Biswas, Gautam

    2010-11-01

    Cortical blindness is defined as visual failure with preserved pupillary reflexes in structurally intact eyes due to bilateral lesions affecting occipital cortex. Bilateral oedema and infarction of the posterior and middle cerebral arterial territory, trauma, glioma and meningioma of the occipital cortex are the main causes of cortical blindness. Posterior reversible encephalopathy syndrome (PRES) refers to the reversible subtype of cortical blindness and is usually associated with hypertension, diabetes, immunosuppression, puerperium with or without eclampsia. Here, 3 cases of PRES with complete or partial visual recovery following treatment in 6-month follow-up are reported.

  15. Introduction to reversible computing

    CERN Document Server

    Perumalla, Kalyan S

    2013-01-01

    Few books comprehensively cover the software and programming aspects of reversible computing. Filling this gap, Introduction to Reversible Computing offers an expanded view of the field that includes the traditional energy-motivated hardware viewpoint as well as the emerging application-motivated software approach. Collecting scattered knowledge into one coherent account, the book provides a compendium of both classical and recently developed results on reversible computing. It explores up-and-coming theories, techniques, and tools for the application of rever

  16. Reversible Logic Circuit Synthesis

    CERN Document Server

    Shende, V V; Markov, I L; Prasad, A K; Hayes, John P.; Markov, Igor L.; Prasad, Aditya K.; Shende, Vivek V.

    2002-01-01

    Reversible, or information-lossless, circuits have applications in digital signal processing, communication, computer graphics and cryptography. They are also a fundamental requirement for quantum computation. We investigate the synthesis of reversible circuits that employ a minimum number of gates and contain no redundant input-output line-pairs (temporary storage channels). We propose new constructions for reversible circuits composed of NOT, Controlled-NOT, and TOFFOLI gates (the CNT gate library) based on permutation theory. A new algorithm is given to synthesize optimal reversible circuits using an arbitrary gate library. We also describe much faster heuristic algorithms. We also pursue applications of the proposed techniques to the synthesis of quantum circuits.

  17. Reverse Core Engine with Thrust Reverser

    Science.gov (United States)

    Suciu, Gabriel L. (Inventor); Chandler, Jesse M. (Inventor)

    2017-01-01

    An engine system has a gas generator, a bi-fi wall surrounding at least a portion of the gas generator, a casing surrounding a fan, and the casing having first and second thrust reverser doors which in a deployed position abut each other and the bi-fi wall.

  18. Time Reversal Violation

    Energy Technology Data Exchange (ETDEWEB)

    Quinn, H; /SLAC

    2009-01-27

    This talk briefly reviews three types of time-asymmetry in physics, which I classify as universal, macroscopic and microscopic. Most of the talk is focused on the latter, namely the violation of T-reversal invariance in particle physics theories. In sum tests of microscopic T-invariance, or observations of its violation, are limited by the fact that, while we can measure many processes, only in very few cases can we construct a matched pair of process and inverse process and observe it with sufficient sensitivity to make a test. In both the cases discussed here we can achieve an observable T violation making use of flavor tagging, and in the second case also using the quantum properties of an antisymmetric coherent state of two B mesons to construct a CP-tag. Both these tagging properties depend only on very general properties of the flavor and/or CP quantum numbers and so provide model independent tests for T-invariance violations. The microscopic laws of physics are very close to T-symmetric. There are small effects that give CP- and T-violating processes in three-generation-probing weak decays. Where a T-violating observable can be constructed we see the relationships between T-violation and CP-violation expected in a CPT conserving theory. These microscopic effects are unrelated to the 'arrow of time' that is defined by increasing entropy, or in the time direction defined by the expansion of our Universe.

  19. Directed destabilization of lysozyme in protic ionic liquids reveals a compact, low energy, soluble, reversibly-unfolding (pre-fibril) state

    CERN Document Server

    Byrne, Nolene; Angell, C Austen

    2007-01-01

    Recent demonstrations of extraordinary stabilization of proteins in mobile protic [1] and aprotic [2] ionic liquid solutions at ambient temperatures have raised hopes of new biopreservation and drug transportation technologies. Here we examine the relation of folded protein stability to the state of the transferred proton [1], as determined by the N-H proton chemical shift, d(N-H). We identify a range of d(N-H) in which the unfolded lysozyme refolds 97%. Exceeding the stability range in the acid direction leads to the sudden formation and stabilization of a small, soluble, amyloid form of lysozyme which has its own stability range and which can again unfold/refold many times before an irreversible process, fibrillization, occurs. The tightly bound amyloid form of the lysozyme molecule, identified by circular dichroism spectra and dynamic light scattering, must be of very low energy since the unfolding process absorbs almost three times the enthalpy of normal lysozyme unfolding. alpha-lactalbumin shows similar...

  20. The puzzling case of the accreting millisecond X-ray pulsar IGR J00291+5934: flaring optical emission during quiescence

    Science.gov (United States)

    Baglio, M. C.; Campana, S.; D'Avanzo, P.; Papitto, A.; Burderi, L.; Di Salvo, T.; Muñoz-Darias, T.; Rea, N.; Torres, D. F.

    2017-04-01

    We present an optical (gri) study during quiescence of the accreting millisecond X-ray pulsar IGR J00291+5934 performed with the 10.4 m Gran Telescopio Canarias (GTC) in August 2014. Although the source was in quiescence at the time of our observations, it showed a strong optical flaring activity, more pronounced in bluer filters (i.e. the g-band). After subtracting the flares, we tentatively recovered a sinusoidal modulation at the system orbital period in all bands, even when a significant phase shift with respect to an irradiated star, typical of accreting millisecond X-ray pulsars, was detected. We conclude that the observed flaring could be a manifestation of the presence of an accretion disc in the system. The observed light curve variability could be explained by the presence of a superhump, which might be another proof of the formation of an accretion disc. In particular, the disc at the time of our observations was probably preparing the new outburst of the source, which occurred a few months later, in 2015. Based on observations made with the Gran Telescopio Canarias (GTC), installed in the Spanish Observatorio del Roque de los Muchachos of the Instituto de Astrofísica de Canarias, in the island of La Palma.

  1. Daily, multiwavelength Swift monitoring of the neutron star low-mass X-ray binary Cen X-4: evidence for accretion and reprocessing during quiescence

    CERN Document Server

    Bernardini, F; Brown, E F; Degenaar, C D'Angelo N; Miller, J M; Reynolds, M; Wijnands, R

    2013-01-01

    The physics of accretion during quiescence in low mass X-ray binaries (LMXBs) is poorly understood, yet there are signs that accretion must be happening. Several LMXBs show variability during quiescence, particularly striking is the case of the nearby neutron star Cen X-4. With the goal of unveiling the real nature of its quiescent variability we conducted the first long-term, multiwavelength simultaneous monitoring of Cen X-4, thanks to 60 observations performed by Swift on a daily basis. During those observations, Cen X-4 is highly variable in all energy bands on timescales from days to months, with the strongest quiescent short-term variability detected in the X-ray band, a factor of 22 drop in only 4 days. The X-ray and the UV and optical emission are correlated on timescales down to less than 110 s. The shape of the correlation is a power law with index 0.2-0.6. The X-ray spectrum is well fitted by a hydrogen NS atmosphere (kT=59-80 eV) and a power law (spectral index 1.4-2.0). The spectral shape remains...

  2. The black hole candidate XTE J1752-223 towards and in quiescence: optical and simultaneous X-ray - radio observations

    CERN Document Server

    Ratti, E M; Miller-Jones, J C A; Torres, M A P; Homan, J; Markoff, S; Tomsick, J A; Kaaret, P; Wijnands, R; Gallo, E; Ozel, F; Steeghs, D T H; Fender, R P

    2012-01-01

    We present optical, X-ray and radio observations of the black hole transient (BHT) XTE J1752-223 towards and in quiescence. Optical photometry shows that the quiescent magnitude of XTE J1752-223 is fainter than 24.4 magnitudes in the i'-band. A comparison with measurements of the source during its 2009-2010 outburst shows that the outburst amplitude is more than 8 magnitudes in the i'-band. Known X-ray properties of the source combined with the faintness of the quiescence optical counterpart and the large outburst optical amplitude point towards a short orbital period system (Porb<~6.8 h) with an M type (or later) mass donor, at a distance of 3.5<~d<~8 kpc. Simultaneous X-ray and radio data were collected with Chandra and the EVLA, allowing constraints to be placed on the quiescent X-ray and radio flux of XTE J1752-223. Furthermore, using data covering the final stage of the outburst decay, we investigated the low luminosity end of the X-ray - radio correlation for this source and compared it with ot...

  3. A Chandra observation of the long-duration X-ray transient KS 1731-260 in quiescence too cold a neutron star?

    CERN Document Server

    Wijnands, R; Markwardt, C B; Lewin, W H G; Van der Klis, M; Wijnands, Rudy; Miller, Jon M.; Markwardt, Craig; Lewin, Walter H. G.; Klis, Michiel van der

    2001-01-01

    After more than a decade of actively accreting at about a tenth of the Eddington critical mass accretion rate, the neutron-star X-ray transient KS 1731-260 returned to quiescence in early 2001. We present a Chandra/ACIS-S observation taken several months after this transition. We detected the source at an unabsorbed flux of ~2 x 10^{-13} erg/s/cm^2 (0.5-10 keV). For a distance of 7 kpc, this results in a 0.5-10 keV luminosity of ~1 x 10^{33} erg/s and a bolometric luminosity approximately twice that. The quiescent luminosity of KS 1731-260 is very similar to that of the other quiescent neutron star systems. However, if this quiescent X-ray luminosity is due to the cooling of the neutron star, this low luminosity may indicate that the source spends several hundreds of years in quiescence in between outbursts for the neutron star to cool. If true, then it might be the first such X-ray transient to be identified and a class of several hundred similar systems might be present in the Galaxy. Alternatively, enhance...

  4. Quantum reverse hypercontractivity

    Energy Technology Data Exchange (ETDEWEB)

    Cubitt, Toby [Department of Computer Science, University College London, London, United Kingdom and Centre for Quantum Information and Foundations, DAMTP, University of Cambridge, Cambridge (United Kingdom); Kastoryano, Michael [NBIA, Niels Bohr Institute, University of Copenhagen, 2100 Copenhagen (Denmark); Montanaro, Ashley [School of Mathematics, University of Bristol, Bristol (United Kingdom); Temme, Kristan [Institute for Quantum Information and Matter, California Institute of Technology, Pasadena, California 91125 (United States)

    2015-10-15

    We develop reverse versions of hypercontractive inequalities for quantum channels. By generalizing classical techniques, we prove a reverse hypercontractive inequality for tensor products of qubit depolarizing channels. We apply this to obtain a rapid mixing result for depolarizing noise applied to large subspaces and to prove bounds on a quantum generalization of non-interactive correlation distillation.

  5. Clocked Thrust Reversers

    Science.gov (United States)

    Suciu, Gabriel L. (Inventor); Chandler, Jesse M. (Inventor)

    2017-01-01

    An aircraft includes a fuselage including a propulsion system supported within an aft portion. A thrust reverser is mounted proximate to the propulsion system for directing thrust in a direction to slow the aircraft. The thrust reverser directs thrust at an angle relative to a vertical plane to reduce interference on control surfaces and reduce generation of underbody lift.

  6. Atrioventricular Pacemaker Lead Reversal

    Directory of Open Access Journals (Sweden)

    Mehmet K Aktas, MD

    2007-01-01

    Full Text Available During cardiac surgery temporary epicardial atrial and ventricular leads are placed in case cardiac pacing is required postoperatively. We present the first reported series of patients with reversal of atrioventricular electrodes in the temporary pacemaker without any consequent deleterious hemodynamic effect. We review the electrocardiographic findings and discuss the findings that lead to the discovery of atrioventricular lead reversal.

  7. Reversible cerebral vasoconstriction syndrome

    Directory of Open Access Journals (Sweden)

    Saini Monica

    2009-01-01

    Full Text Available Reversible cerebral vasoconstriction syndromes (RCVS are a group of disorders that have in common an acute presentation with headache, reversible vasoconstriction of cerebral arteries, with or without neurological signs and symptoms. In contrast to primary central nervous system vasculitis, they have a relatively benign course. We describe here a patient who was diagnosed with RCVS.

  8. Reversible Simulations of Elastic Collisions

    CERN Document Server

    Perumalla, Kalyan S

    2013-01-01

    Consider a system of N identical hard spherical particles moving in a d-dimensional box and undergoing elastic, possibly multi-particle, collisions. We develop a new algorithm that recovers the pre-collision state from the post-collision state of the system, across a series of consecutive collisions, with essentially no memory overhead. The challenge in achieving reversibility for an n-particle collision (where, n << N) arises from the presence of nd-d-1 degrees of freedom during each collision, and from the complex geometrical constraints placed on the colliding particles. To reverse the collisions in a traditional simulation setting, all of the particular realizations of these degrees of freedom during the forward simulation must be saved. This limitation is addressed here by first performing a pseudo-randomization of angles, ensuring determinism in the reverse path for any values of n and d. To address the more difficult problem of geometrical and dynamic constraints, a new approach is developed whic...

  9. Towards Reversible Sessions

    Directory of Open Access Journals (Sweden)

    Francesco Tiezzi

    2014-06-01

    Full Text Available In this work, we incorporate reversibility into structured communication-based programming, to allow parties of a session to automatically undo, in a rollback fashion, the effect of previously executed interactions. This permits taking different computation paths along the same session, as well as reverting the whole session and starting a new one. Our aim is to define a theoretical basis for examining the interplay in concurrent systems between reversible computation and session-based interaction. We thus enrich a session-based variant of pi-calculus with memory devices, dedicated to keep track of the computation history of sessions in order to reverse it. We discuss our initial investigation concerning the definition of a session type discipline for the proposed reversible calculus, and its practical advantages for static verification of safe composition in communication-centric distributed software performing reversible computations.

  10. [Posterior reversible encephalopathy syndrome].

    Science.gov (United States)

    Petrović, Branko; Kostić, Vladimir; Sternić, Nadezda; Kolar, Jovo; Tasić, Nebojsa

    2003-01-01

    with lowering of blood pressure, better mental state and better vision. There was no sign of left hemiparesis on the 7th day. On the 9th day there were no symptoms or sign of disease. Control brain CT (15th day) was normal. ETHIOPATHOGENESIS: Most common causes of PRES are hypertensive encephalopathy [6-8], pre-eclampsia/eclampsia [9-12] cyclosporin A administration [13-22] and uremic encephalopathy [23]. There are several theories about the mechanism for PRES in hypertensive encephalopathy (reversible vasospasm and hyperperfusion) and administration of cyclosporin A (neurotoxic effect). Most common symptoms are headache, nausea, vomiting, confusion, behavioural changes, changes of conciousness (from somnolencia to stupor), vision disturbances (blurred vision, haemianopsia, cortical blindness) and epileptic manifestations (mostly focal attacks with secondary generalisation). Mental functions are characterised with decreased activity and reactivity, confusion, loss of concentration and mild type of amnesia. Lethargy is often initial sign, sometimes accompanied with phases of agitation. Stupor and coma rarely occurred. In patients with hypertensive encephalopathy and eclampsia high blod pressure is registered. Neurological examination revealed vision changes and damages of mental function as well as increased reflex activity. Today, brain MRI and CT are considered the most important diagnostic method for the diagnosis and follow-up of patients with PRES [6]. Brain MRI better detects smaller focal parenhim abnormalities than brain CT. The most often neuroradiological finding is relatively symmetrical oedema of white cerebral tissue in parieto-occipital regions of both cerebral hemispheres. Gray cerebral tissue is sometimes involved, usually in mild form of disease. Diagnosis of this "cortical" form of PRES is possible by MR FLAIR (Fluid-Attenuated Inversion Recovery) technique [5]. Therapeutic strategy depends on the cause of PRES and clinical picture. Most important are

  11. Chemical reactions in reverse micelle systems

    Science.gov (United States)

    Matson, Dean W.; Fulton, John L.; Smith, Richard D.; Consani, Keith A.

    1993-08-24

    This invention is directed to conducting chemical reactions in reverse micelle or microemulsion systems comprising a substantially discontinuous phase including a polar fluid, typically an aqueous fluid, and a microemulsion promoter, typically a surfactant, for facilitating the formation of reverse micelles in the system. The system further includes a substantially continuous phase including a non-polar or low-polarity fluid material which is a gas under standard temperature and pressure and has a critical density, and which is generally a water-insoluble fluid in a near critical or supercritical state. Thus, the microemulsion system is maintained at a pressure and temperature such that the density of the non-polar or low-polarity fluid exceeds the critical density thereof. The method of carrying out chemical reactions generally comprises forming a first reverse micelle system including an aqueous fluid including reverse micelles in a water-insoluble fluid in the supercritical state. Then, a first reactant is introduced into the first reverse micelle system, and a chemical reaction is carried out with the first reactant to form a reaction product. In general, the first reactant can be incorporated into, and the product formed in, the reverse micelles. A second reactant can also be incorporated in the first reverse micelle system which is capable of reacting with the first reactant to form a product.

  12. Szilard engine reversibility as quantum gate function

    Science.gov (United States)

    Mihelic, F. Matthew

    2012-06-01

    A quantum gate is a logically and thermodynamically reversible situation that effects a unitary transformation of qubits of superimposed information, and essentially constitutes a situation for a reversible quantum decision. A quantum decision is a symmetry break, and the effect of the function of a Szilard engine is a symmetry break. A quantum gate is a situation in which a reversible quantum decision can be made, and so if a logically and thermodynamically reversible Szilard engine can be theoretically constructed then it would function as a quantum gate. While the traditionally theorized Szilard engine is not thermodynamically reversible, if one of the bounding walls of a Szilard engine were to be constructed out of the physical information by which it functions in such a manner as to make that information available to both sides of the wall simultaneously, then such a Szilard engine would be both logically and thermodynamically reversible, and thus capable of function as a quantum gate. A theoretical model of the special case of a reversible Szilard engine functioning as a quantum gate is presented and discussed, and since a quantum decision is made when the shutter of a Szilard engine closes, the coherence of linked reversible Szilard engines should be considered as a state during which all of the shutters of linked Szilard engines are open simultaneously.

  13. SLE local martingales, reversibility and duality

    Energy Technology Data Exchange (ETDEWEB)

    Kytoelae, Kalle; Kemppainen, Antti [Department of Mathematics and Statistics, PO Box 68, FIN-00014 University of Helsinki (Finland)

    2006-11-17

    We study Schramm-Loewner evolutions (SLEs) reversibility and duality using the Virasoro structure of the space of local martingales. For both problems we formulate a setup where the questions boil down to comparing two processes at a stopping time. We state algebraic results showing that local martingales for the processes have enough in common. When one has in addition integrability, the method gives reversibility and duality for any polynomial expected value. (letter to the editor)

  14. An algebra of reversible computation

    OpenAIRE

    2016-01-01

    We design an axiomatization for reversible computation called reversible ACP (RACP). It has four extendible modules, basic reversible processes algebra (BRPA), algebra of reversible communicating processes (ARCP), recursion and abstraction. Just like process algebra ACP in classical computing, RACP can be treated as an axiomatization foundation for reversible computation.

  15. An Algebra of Reversible Computation

    OpenAIRE

    Yong WANG

    2014-01-01

    We design an axiomatization for reversible computation called reversible ACP (RACP). It has four extendible modules, basic reversible processes algebra (BRPA), algebra of reversible communicating processes (ARCP), recursion and abstraction. Just like process algebra ACP in classical computing, RACP can be treated as an axiomatization foundation for reversible computation.

  16. An algebra of reversible computation.

    Science.gov (United States)

    Wang, Yong

    2016-01-01

    We design an axiomatization for reversible computation called reversible ACP (RACP). It has four extendible modules: basic reversible processes algebra, algebra of reversible communicating processes, recursion and abstraction. Just like process algebra ACP in classical computing, RACP can be treated as an axiomatization foundation for reversible computation.

  17. Reversible Data Hiding Techniques

    Directory of Open Access Journals (Sweden)

    Dhananjay Yadav

    2012-03-01

    Full Text Available Reversible data hiding is a technique that is used to hide data inside an image. The data is hidden in such a way that the exact or original data is not visible. The hidden data can be retrieved as and when required. There are several methods that are used in reversible data hiding techniques like Watermarking, Lossless embedding and encryption. In this paper we present a review of reversible watermarking techniques and show different methods that are used to get reversible data hiding technique with higher embedding capacity and invisible objects. Watermark need not be hidden. Watermarking can be applied to 1. Images, 2. Text, 3. Audio/video, 4. Software.

  18. Reversible flowchart languages and the structured reversible program theorem

    DEFF Research Database (Denmark)

    Yokoyama, Tetsuo; Axelsen, Holger Bock; Glück, Robert

    2008-01-01

    Many irreversible computation models have reversible counterparts, but these are poorly understood at present. We introduce reversible flowcharts with an assertion operator and show that any reversible flowchart can be simulated by a structured reversible flowchart using only three control flow o...... justification for low-level machine code for reversible microprocessors as well as high-level block-structured reversible languages. We give examples for both such languages and illustrate them with a lossless encoder for permutations given by Dijkstra....

  19. Reversible logic synthesis methodologies with application to quantum computing

    CERN Document Server

    Taha, Saleem Mohammed Ridha

    2016-01-01

    This book opens the door to a new interesting and ambitious world of reversible and quantum computing research. It presents the state of the art required to travel around that world safely. Top world universities, companies and government institutions  are in a race of developing new methodologies, algorithms and circuits on reversible logic, quantum logic, reversible and quantum computing and nano-technologies. In this book, twelve reversible logic synthesis methodologies are presented for the first time in a single literature with some new proposals. Also, the sequential reversible logic circuitries are discussed for the first time in a book. Reversible logic plays an important role in quantum computing. Any progress in the domain of reversible logic can be directly applied to quantum logic. One of the goals of this book is to show the application of reversible logic in quantum computing. A new implementation of wavelet and multiwavelet transforms using quantum computing is performed for this purpose. Rese...

  20. On thermodynamic and microscopic reversibility

    Energy Technology Data Exchange (ETDEWEB)

    Crooks, Gavin E.

    2011-07-12

    The word 'reversible' has two (apparently) distinct applications in statistical thermodynamics. A thermodynamically reversible process indicates an experimental protocol for which the entropy change is zero, whereas the principle of microscopic reversibility asserts that the probability of any trajectory of a system through phase space equals that of the time reversed trajectory. However, these two terms are actually synonymous: a thermodynamically reversible process is microscopically reversible, and vice versa.

  1. Age-Associated Methylation Suppresses SPRY1, Leading to a Failure of Re-quiescence and Loss of the Reserve Stem Cell Pool in Elderly Muscle

    Directory of Open Access Journals (Sweden)

    Anne Bigot

    2015-11-01

    Full Text Available The molecular mechanisms by which aging affects stem cell number and function are poorly understood. Murine data have implicated cellular senescence in the loss of muscle stem cells with aging. Here, using human cells and by carrying out experiments within a strictly pre-senescent division count, we demonstrate an impaired capacity for stem cell self-renewal in elderly muscle. We link aging to an increased methylation of the SPRY1 gene, a known regulator of muscle stem cell quiescence. Replenishment of the reserve cell pool was modulated experimentally by demethylation or siRNA knockdown of SPRY1. We propose that suppression of SPRY1 by age-associated methylation in humans inhibits the replenishment of the muscle stem cell pool, contributing to a decreased regenerative response in old age. We further show that aging does not affect muscle stem cell senescence in humans.

  2. Age-Associated Methylation Suppresses SPRY1, Leading to a Failure of Re-quiescence and Loss of the Reserve Stem Cell Pool in Elderly Muscle.

    Science.gov (United States)

    Bigot, Anne; Duddy, William J; Ouandaogo, Zamalou G; Negroni, Elisa; Mariot, Virginie; Ghimbovschi, Svetlana; Harmon, Brennan; Wielgosik, Aurore; Loiseau, Camille; Devaney, Joe; Dumonceaux, Julie; Butler-Browne, Gillian; Mouly, Vincent; Duguez, Stéphanie

    2015-11-10

    The molecular mechanisms by which aging affects stem cell number and function are poorly understood. Murine data have implicated cellular senescence in the loss of muscle stem cells with aging. Here, using human cells and by carrying out experiments within a strictly pre-senescent division count, we demonstrate an impaired capacity for stem cell self-renewal in elderly muscle. We link aging to an increased methylation of the SPRY1 gene, a known regulator of muscle stem cell quiescence. Replenishment of the reserve cell pool was modulated experimentally by demethylation or siRNA knockdown of SPRY1. We propose that suppression of SPRY1 by age-associated methylation in humans inhibits the replenishment of the muscle stem cell pool, contributing to a decreased regenerative response in old age. We further show that aging does not affect muscle stem cell senescence in humans.

  3. Cellular Barcoding Links B-1a B Cell Potential to a Fetal Hematopoietic Stem Cell State at the Single-Cell Level

    DEFF Research Database (Denmark)

    Kristiansen, Trine A; Jaensson Gyllenbäck, Elin; Zriwil, Alya

    2016-01-01

    Hematopoietic stem cells (HSCs) undergo a functional switch in neonatal mice hallmarked by a decrease in self-renewing divisions and entry into quiescence. Here, we investigated whether the developmental attenuation of B-1a cell output is a consequence of a shift in stem cell state during ontogeny...

  4. Loss of T cell and B cell quiescence precedes the onset of microbial flora-dependent wasting disease and intestinal inflammation in Gimap5-deficient mice.

    Science.gov (United States)

    Barnes, Michael J; Aksoylar, Halil; Krebs, Philippe; Bourdeau, Tristan; Arnold, Carrie N; Xia, Yu; Khovananth, Kevin; Engel, Isaac; Sovath, Sosathya; Lampe, Kristin; Laws, Eleana; Saunders, Amy; Butcher, Geoffrey W; Kronenberg, Mitchell; Steinbrecher, Kris; Hildeman, David; Grimes, H Leighton; Beutler, Bruce; Hoebe, Kasper

    2010-04-01

    Homeostatic control of the immune system involves mechanisms that ensure the self-tolerance, survival and quiescence of hematopoietic-derived cells. In this study, we demonstrate that the GTPase of immunity associated protein (Gimap)5 regulates these processes in lymphocytes and hematopoietic progenitor cells. As a consequence of a recessive N-ethyl-N-nitrosourea-induced germline mutation in the P-loop of Gimap5, lymphopenia, hepatic extramedullary hematopoiesis, weight loss, and intestinal inflammation occur in homozygous mutant mice. Irradiated fetal liver chimeric mice reconstituted with Gimap5-deficient cells lose weight and become lymphopenic, demonstrating a hematopoietic cell-intrinsic function for Gimap5. Although Gimap5-deficient CD4(+) T cells and B cells appear to undergo normal development, they fail to proliferate upon Ag-receptor stimulation although NF-kappaB, MAP kinase and Akt activation occur normally. In addition, in Gimap5-deficient mice, CD4(+) T cells adopt a CD44(high)CD62L(low)CD69(low) phenotype and show reduced IL-7ralpha expression, and T-dependent and T-independent B cell responses are abrogated. Thus, Gimap5-deficiency affects a noncanonical signaling pathway required for Ag-receptor-induced proliferation and lymphocyte quiescence. Antibiotic-treatment or the adoptive transfer of Rag-sufficient splenocytes ameliorates intestinal inflammation and weight loss, suggesting that immune responses triggered by microbial flora causes the morbidity in Gimap5-deficient mice. These data establish Gimap5 as a key regulator of hematopoietic integrity and lymphocyte homeostasis.

  5. The black hole candidate XTE J1752-223 towards and in quiescence: optical and simultaneous X-ray-radio observations

    Science.gov (United States)

    Ratti, E. M.; Jonker, P. G.; Miller-Jones, J. C. A.; Torres, M. A. P.; Homan, J.; Markoff, S.; Tomsick, J. A.; Kaaret, P.; Wijnands, R.; Gallo, E.; Özel, F.; Steeghs, D. T. H.; Fender, R. P.

    2012-07-01

    We present optical, X-ray and radio observations of the black hole transient (BHT) XTE J1752-223 towards and in quiescence. Optical photometry shows that the quiescent magnitude of XTE J1752-223 is fainter than 24.4 mag in the i' band. A comparison with measurements of the source during its 2009-2010 outburst shows that the outburst amplitude is more than 8 mag in the i' band. Known X-ray properties of the source combined with the faintness of the quiescence optical counterpart and the large outburst optical amplitude point towards a short orbital-period system (Porb≲ 6.8 h) with an M type (or later) mass donor, at a distance of 3.5 ≲d≲ 8 kpc. Simultaneous X-ray and radio data were collected with Chandra and the Expanded Very Large Array (EVLA), allowing constraints to be placed on the quiescent X-ray and radio flux of XTE J1752-223. Furthermore, using data covering the final stage of the outburst decay, we investigated the low-luminosity end of the X-ray-radio correlation for this source and compared it with other BHTs. We found that XTE J1752-223 adds to the number of outliers with respect to the 'standard' X-ray-radio luminosity relation. Furthermore, XTE J1752-223 is the second source, after the BHT H1743-322, that shows a transition from the region of the outliers towards the 'standard' correlation at low luminosity. Finally, we report on a faint, variable X-ray source we discovered with Chandra at an angular distance of ˜2.9 arcsec to XTE J1752-223 and at a position angle consistent with that of the radio jets previously observed from the BHT. We discuss the possibility that we detected X-ray emission associated with a jet from XTE J1752-223.

  6. A Case for Dynamic Reverse-code Generation

    DEFF Research Database (Denmark)

    Lee, Jooyong

    2007-01-01

    Backtracking (i.e. reverse execution) helps the user of a debugger to naturally think backwards along the execution path of a program, and thinking backwards makes it easy to locate the origin of a bug. So far backtracking has been implemented mostly by state saving or by checkpointing....... These implementations, however, inherently do not scale. As has often been said, the ultimate solution for backtracking is to use reverse code: executing the reverse code restores the previous states of a program. In our earlier work, we presented a method to generate reverse code on the fly while running a debugger...

  7. Radiation controlling reversible window

    Energy Technology Data Exchange (ETDEWEB)

    Gell, H.A. Jr.

    1980-01-01

    A coated glass glazing system is presented including a transparent glass substrate having one surface coated with a radiation absorptive film which is overcoated with a radiation reflective film by a technique which renders the radiation reflective film radiation absorptive at the surface contracting the radiating absorptive film. The coated glass system is used as glazing for storm windows which are adapted to be reversible so that the radiation reflective surface may be exposed to the outside of the dwelling during the warm seasons to prevent excessive solar radiation from entering a dwelling and reversed during cold seasons to absorb solar radiation and utilize it to aid in keeping the dwelling interior warm.

  8. Conditional reversibility in nonequilibrium stochastic systems

    Science.gov (United States)

    Bonança, Marcus V. S.; Jarzynski, Christopher

    2016-02-01

    For discrete-state stochastic systems obeying Markovian dynamics, we establish the counterpart of the conditional reversibility theorem obtained by Gallavotti for deterministic systems [Ann. de l'Institut Henri Poincaré (A) 70, 429 (1999)]. Our result states that stochastic trajectories conditioned on opposite values of entropy production are related by time reversal, in the long-time limit. In other words, the probability of observing a particular sequence of events, given a long trajectory with a specified entropy production rate σ , is the same as the probability of observing the time-reversed sequence of events, given a trajectory conditioned on the opposite entropy production, -σ , where both trajectories are sampled from the same underlying Markov process. To obtain our result, we use an equivalence between conditioned ("microcanonical") and biased ("canonical") ensembles of nonequilibrium trajectories. We provide an example to illustrate our findings.

  9. Sequential Polarity-Reversing Circuit

    Science.gov (United States)

    Labaw, Clayton C.

    1994-01-01

    Proposed circuit reverses polarity of electric power supplied to bidirectional dc motor, reversible electro-mechanical actuator, or other device operating in direction depending on polarity. Circuit reverses polarity each time power turned on, without need for additional polarity-reversing or direction signals and circuitry to process them.

  10. Time reversal communication system

    Science.gov (United States)

    Candy, James V.; Meyer, Alan W.

    2008-12-02

    A system of transmitting a signal through a channel medium comprises digitizing the signal, time-reversing the digitized signal, and transmitting the signal through the channel medium. The channel medium may be air, earth, water, tissue, metal, and/or non-metal.

  11. Engineering Encounters: Reverse Engineering

    Science.gov (United States)

    McGowan, Veronica Cassone; Ventura, Marcia; Bell, Philip

    2017-01-01

    This column presents ideas and techniques to enhance your science teaching. This month's issue shares information on how students' everyday experiences can support science learning through engineering design. In this article, the authors outline a reverse-engineering model of instruction and describe one example of how it looked in our fifth-grade…

  12. Reverse Coherent Information

    Science.gov (United States)

    García-Patrón, Raúl; Pirandola, Stefano; Lloyd, Seth; Shapiro, Jeffrey H.

    2009-05-01

    In this Letter we define a family of entanglement distribution protocols assisted by feedback classical communication that gives an operational interpretation to reverse coherent information, i.e., the symmetric counterpart of the well-known coherent information. This leads to the definition of a new entanglement distribution capacity that exceeds the unassisted capacity for some interesting channels.

  13. Reversed extension flow

    DEFF Research Database (Denmark)

    Nielsen, Jens Kromann; Rasmussen, Henrik K.

    2008-01-01

    Afilament stretching rheometer (FSR) was used for measuring the start-up of uni-axial elongational flow followed by reversed bi-axial flow, both with a constant elongational rate. A narrow molecular mass distribution linear polystyrene with a molecular weight of 145 kg / mole wis subjected to the...

  14. REVERSE SUPPLY CHAIN

    Directory of Open Access Journals (Sweden)

    Tomasz DOMAGAŁA

    2013-10-01

    Full Text Available The paper focuses on the presentation of the reverse supply chain, of which the role in the modern business grows along with the increasing number of environmental regulations and possibilities of reducing an operating cost. The paper also describes main problems in developing the profitable chain and possibilities to take an action in order to overcome them.

  15. On reverse hypercontractivity

    CERN Document Server

    Mossel, Elchanan; Sen, Arnab

    2011-01-01

    We study the notion of reverse hypercontractivity. We show that reverse hypercontractive inequalities are implied by standard hypercontractive inequalities as well as by the modified log-Sobolev inequality. Our proof is based on a new comparison lemma for Dirichlet forms and an extension of the Strook-Varapolos inequality. A consequence of our analysis is that {\\em all} simple operators $L=Id-\\E$ as well as their tensors satisfy uniform reverse hypercontractive inequalities. That is, for all $qreverse hypercontractive inequalities established here imply new mixing and isoperimetric results for short random walks in product spaces, for certain card-shufflings, for Glauber dynamics in high-temperat...

  16. Reversing Discrimination: A Perspective

    Science.gov (United States)

    Pati, Gopal; Reilly, Charles W.

    1977-01-01

    Examines the debate over affirmative action and reverse discrimination, and discusses how and why the present dilemma has developed. Suggests that organizations can best address the problem through an honest, in-depth analysis of their organizational structure and management practices. (JG)

  17. The interface states and series resistance effects on the forward and reverse bias I-V, C-V and G/{omega}-V characteristics of Al-TiW-Pd{sub 2}Si/n-Si Schottky barrier diodes

    Energy Technology Data Exchange (ETDEWEB)

    Uslu, H.; Altindal, S.; Aydemir, U. [Department of Physics, Gazi University, 06500 Ankara (Turkey); Doekme, I., E-mail: ilbilgedokme@gazi.edu.t [Science Education Department, Gazi Education Faculty, Gazi University, 06500 Ankara (Turkey); Afandiyeva, I.M. [Baku State University, Baku (Azerbaijan)

    2010-07-30

    Illumination intensity effects on the electrical characteristics of Al-TiW-Pd{sub 2}Si/n-Si Schottky structures have been investigated in this study for the first time. The electrical parameters such as ideality factor (n), zero-bias-barrier height ({Phi}{sub B0}), series resistance (R{sub s}), depletion layer width (W{sub D}) and dopping concentration (N{sub D}) of Al-TiW-Pd{sub 2}Si/n-Si Schottky barrier diodes (SBDs) have been investigated by using the forward and reverse bias current-voltage (I-V), capacitance-voltage (C-V) and conductance-voltage (G/{omega}-V) measurements in dark and under illumination conditions at room temperature. The values of C and G/{omega} increase with increasing illumination intensity due to the illumination induced electron-hole pairs in the depletion region. The density of interface states (N{sub ss}) distribution profiles as a function of (E{sub c} - E{sub ss}) was extracted from the forward I-V measurements by taking into account the bias dependence of the effective barrier heights ({Phi}{sub e}) for device in dark and under various illumination intensities. The high values of N{sub ss} were responsible for the nonideal behavior of I-V, C-V and G/{omega} characteristics. The values of R{sub s} obtained from Cheung and Nicollian methods decrease with increasing illumination intensity. The high values of n and R{sub s} have been attributed to the particular distribution of N{sub ss}, surface preparation, inhomogeneity of interfacial layer and barrier height at metal/semiconductor (M/S) interface. As a result, the characteristics of SBD are affected not only in N{sub ss} but also in R{sub s}, and these two parameters strongly influence the electrical parameters.

  18. A Gaussian Model for Simulated Geomagnetic Field Reversals

    CERN Document Server

    Wicht, Johannes

    2015-01-01

    Field reversals are the most spectacular changes in the geomagnetic field but remain little understood. Paleomagnetic data primarily constrain the reversal rate and provide few additional clues. Reversals and excursions are characterized by a low in dipole moment that can last for some 10kyr. Some paleomagnetic records also suggest that the field decreases much slower before an reversals than it recovers afterwards and that the recovery phase may show an overshoot in field intensity. Here we study the dipole moment variations in several extremely long dynamo simulation to statistically explored the reversal and excursion properties. The numerical reversals are characterized by a switch from a high axial dipole moment state to a low axial dipole moment state. When analysing the respective transitions we find that decay and growth have very similar time scales and that there is no overshoot. Other properties are generally similar to paleomagnetic findings. The dipole moment has to decrease to about 30% of its m...

  19. Reversible Logic Elements with Memory and Their Universality

    Directory of Open Access Journals (Sweden)

    Kenichi Morita

    2013-09-01

    Full Text Available Reversible computing is a paradigm of computation that reflects physical reversibility, one of the fundamental microscopic laws of Nature. In this survey, we discuss topics on reversible logic elements with memory (RLEM, which can be used to build reversible computing systems, and their universality. An RLEM is called universal, if any reversible sequential machine (RSM can be realized as a circuit composed only of it. Since a finite-state control and a tape cell of a reversible Turing machine (RTM are formalized as RSMs, any RTM can be constructed from a universal RLEM. Here, we investigate 2-state RLEMs, and show that infinitely many kinds of non-degenerate RLEMs are all universal besides only four exceptions. Non-universality of these exceptional RLEMs is also argued.

  20. Red fluorescent protein with reversibly photoswitchable absorbance for photochromic FRET

    NARCIS (Netherlands)

    Subach, F.V.; Zhang, L.; Gadella, T.W.J.; Gurskaya, N.G.; Lukyanov, K.A.; Verkhusha, V.V.

    2010-01-01

    We have developed the first red fluorescent protein, named rsTagRFP, which possesses reversibly photoswitchable absorbance spectra. Illumination with blue and yellow light switches rsTagRFP into a red fluorescent state (ON state) or nonfluorescent state (OFF state), respectively. The ON and OFF stat

  1. Reversible quantum cellular automata

    CERN Document Server

    Schumacher, B

    2004-01-01

    We define quantum cellular automata as infinite quantum lattice systems with discrete time dynamics, such that the time step commutes with lattice translations and has strictly finite propagation speed. In contrast to earlier definitions this allows us to give an explicit characterization of all local rules generating such automata. The same local rules also generate the global time step for automata with periodic boundary conditions. Our main structure theorem asserts that any quantum cellular automaton is structurally reversible, i.e., that it can be obtained by applying two blockwise unitary operations in a generalized Margolus partitioning scheme. This implies that, in contrast to the classical case, the inverse of a nearest neighbor quantum cellular automaton is again a nearest neighbor automaton. We present several construction methods for quantum cellular automata, based on unitaries commuting with their translates, on the quantization of (arbitrary) reversible classical cellular automata, on quantum c...

  2. Partial Reversible Gates(PRG) for Reversible BCD Arithmetic

    CERN Document Server

    Thapliyal, Himanshu; Bajpai, Rajnish; Sharma, Kamal K

    2007-01-01

    IEEE 754r is the ongoing revision to the IEEE 754 floating point standard and a major enhancement to the standard is the addition of decimal format. Furthermore, in the recent years reversible logic has emerged as a promising computing paradigm having its applications in low power CMOS, quantum computing, nanotechnology, and optical computing. The major goal in reversible logic is to minimize the number of reversible gates and garbage outputs. Thus, this paper proposes the novel concept of partial reversible gates that will satisfy the reversibility criteria for specific cases in BCD arithmetic. The partial reversible gate is proposed to minimize the number of reversible gates and garbage outputs, while designing the reversible BCD arithmetic circuits.

  3. Reversible multi-head finite automata characterize reversible logarithmic space

    DEFF Research Database (Denmark)

    Axelsen, Holger Bock

    2012-01-01

    Deterministic and non-deterministic multi-head finite automata are known to characterize the deterministic and non- deterministic logarithmic space complexity classes, respectively. Recently, Morita introduced reversible multi-head finite automata (RMFAs), and posed the question of whether RMFAs...... characterize reversible logarithmic space as well. Here, we resolve the question affirmatively, by exhibiting a clean RMFA simulation of logarithmic space reversible Turing machines. Indirectly, this also proves that reversible and deterministic multi-head finite automata recognize the same languages....

  4. [Reverse Chaddock sign].

    Science.gov (United States)

    Tashiro, Kunio

    2011-08-01

    It is widely accepted that the Babinski reflex is the most well-known and important pathological reflex in clinical neurology. Among many other pathological reflexes that elicit an upgoing great toe, such as Chaddock, Oppenheim, Gordon, Schaefer, and Stransky, only the Chaddock reflex is said to be as sensitive as the Babinski reflex. The optimal receptive fields of the Babinski and Chaddock reflexes are the lateral plantar surface and the external inframalleolar area of the dorsum, respectively. It has been said that the Babinski reflex, obtained by stroking the sole, is by far the best and most reliable method of eliciting an upgoing great toe. However, the Chaddock reflex, the external malleolar sign, is also considered sensitive and reliable according to the literature and everyday neurological practice. The major problems in eliciting the Babinski reflex by stroking the lateral part of the sole are false positive or negative responses due to foot withdrawal, tonic foot response, or some equivocal movements. On the other hand, according to my clinical experience, the external inframalleolar area, which is the receptive field of the Chaddock reflex, is definitely suitable for eliciting the upgoing great toe. In fact, the newly proposed method to stimulate the dorsum of the foot from the medial to the lateral side, which I term the "reversed Chaddock method," is equally sensitive to demonstrate pyramidal tract involvement. With the "reversed Chaddock method", the receptive field of the Chaddock reflex may be postulated to be in the territory of the sural nerve, which could be supported by the better response obtained on stimulation of the postero-lateral calf than the anterior shin. With regard to the receptive fields of the Babinski and Chaddock reflexes, the first sacral dermatome (S1) is also considered a reflexogenous zone, but since the dermatome shows marked overlapping, the zones vary among individuals. As upgoing toe responses are consistently observed in

  5. Thermodynamically reversible processes in statistical physics

    Science.gov (United States)

    Norton, John D.

    2017-02-01

    Equilibrium states are used as limit states to define thermodynamically reversible processes. When these processes are understood in terms of statistical physics, these limit states can change with time due to thermal fluctuations. For macroscopic systems, the changes are insignificant on ordinary time scales and what little change there is can be suppressed by macroscopically negligible, entropy-creating dissipation. For systems of molecular sizes, the changes are large on short time scales. They can only sometimes be suppressed with significant entropy-creating dissipation, and this entropy creation is unavoidable if any process is to proceed to completion. As a result, at molecular scales, thermodynamically reversible processes are impossible in principle. Unlike the macroscopic case, they cannot be realized even approximately when we account for all sources of dissipation, and argumentation invoking them on molecular scales can lead to spurious conclusions.

  6. The thermodynamics of reversible thermoelectric nanomaterials

    Science.gov (United States)

    Humphrey, Tammy; Linke, Heiner

    2005-03-01

    Irreversible effects in thermoelectric materials limit their efficiency and economy for applications in power generation and refrigeration. While electron transport is unavoidably irreversible in bulk materials, here we derive conditions under which reversible diffusive electron transport can be achieved in nanostructured thermoelectric materials via the same physical mechanism utilized in the three-level amplifier (thermally pumped laser) and idealized thermophotovoltaic and thermionic devices. From a broader physical perspective, the most interesting aspect of this work is that it suggests that all of the above-mentioned solid-state devices may be unified as a single `type' of heat engine which achieves reversibility when heat transfer via particle exchange between reservoirs is isentropic (but non-isothermal), in contrast to heat engines such as Carnot, Otto or Brayton cycles, which achieve reversibility when heat transfer between the working gas and heat reservoirs is isothermal.

  7. What happens when the geomagnetic field reverses?

    CERN Document Server

    Lemaire, Joseph F

    2012-01-01

    During geomagnetic field reversals the radiation belt high-energy proton populations become depleted. Their energy spectra become softer, with the trapped particles of highest energies being lost first, and eventually recovering after a field reversal. The radiation belts rebuild in a dynamical way with the energy spectra flattening on the average during the course of many millennia, but without ever reaching complete steady state equilibrium between successive geomagnetic storm events determined by southward turnings of the IMF orientation. Considering that the entry of galactic cosmic rays and the solar energetic particles with energies above a given threshold are strongly controlled by the intensity of the northward component of the interplanetary magnetic field, we speculate that at earlier epochs when the geomagnetic dipole was reversed, the entry of these energetic particles into the geomagnetic field was facilitated when the interplanetary magnetic field was directed northward. Unlike in other compleme...

  8. Reverse Engineering of RFID devices

    OpenAIRE

    Bokslag, Wouter

    2015-01-01

    This paper discusses the relevance and potential impact of both RFID and reverse engineering of RFID technology, followed by a discussion of common protocols and internals of RFID technology. The focus of the paper is on providing an overview of the different approaches to reverse engineering RFID technology and possible countermeasures that could limit the potential of such reverse engineering attempts.

  9. Two years of INTEGRAL monitoring of the soft gamma-ray repeater SGR 1806-20: from quiescence to frenzy

    DEFF Research Database (Denmark)

    Gotz, D.; Mereghetti, S.; Molkov, S.;

    2006-01-01

    SGR 1806-20 has been observed for more than 2 years with the INTEGRAL satellite. In this period the source went from a quiescent state into a very active one culminating in a giant flare on December 27, 2004. Here we report on the properties of all the short bursts detected with INTEGRAL before t...

  10. Lineage tracing in the adult mouse corneal epithelium supports the limbal epithelial stem cell hypothesis with intermittent periods of stem cell quiescence

    Directory of Open Access Journals (Sweden)

    Natalie J. Dorà

    2015-11-01

    Full Text Available The limbal epithelial stem cell (LESC hypothesis proposes that LESCs in the corneal limbus maintain the corneal epithelium both during normal homeostasis and wound repair. The alternative corneal epithelial stem cell (CESC hypothesis proposes that LESCs are only involved in wound repair and CESCs in the corneal epithelium itself maintain the corneal epithelium during normal homeostasis. We used tamoxifen-inducible, CreER-loxP lineage tracing to distinguish between these hypotheses. Clones of labelled cells were induced in adult CAGG-CreER;R26R-LacZ reporter mice and their distributions analysed after different chase periods. Short-lived clones, derived from labelled transient amplifying cells, were shed during the chase period and long-lived clones, derived from stem cells, expanded. At 6 weeks, labelled clones appeared at the periphery, extended centripetally as radial stripes and a few reached the centre by 14 weeks. Stripe numbers depended on the age of tamoxifen treatment. Stripes varied in length, some were discontinuous, few reached the centre and almost half had one end at the limbus. Similar stripes extended across the cornea in CAGG-CreER;R26R-mT/mG reporter mice. The distributions of labelled clones are inconsistent with the CESC hypothesis and support the LESC hypothesis if LESCs cycle between phases of activity and quiescence, each lasting several weeks.

  11. Melanoma dormancy in a mouse model is linked to GILZ/FOXO3A-dependent quiescence of disseminated stem-like cells.

    Science.gov (United States)

    Touil, Yasmine; Segard, Pascaline; Ostyn, Pauline; Begard, Severine; Aspord, Caroline; El Machhour, Raja; Masselot, Bernadette; Vandomme, Jerome; Flamenco, Pilar; Idziorek, Thierry; Figeac, Martin; Formstecher, Pierre; Quesnel, Bruno; Polakowska, Renata

    2016-07-28

    Metastatic cancer relapses following the reactivation of dormant, disseminated tumour cells; however, the cells and factors involved in this reactivation are just beginning to be identified. Using an immunotherapy-based syngeneic model of melanoma dormancy and GFP-labelled dormant cell-derived cell lines, we determined that vaccination against melanoma prevented tumour growth but did not prevent tumour cell dissemination or eliminate all tumour cells. The persistent disseminated melanoma tumour cells were quiescent and asymptomatic for one year. The quiescence/activation of these cells in vitro and the dormancy of melanoma in vivo appeared to be regulated by glucocorticoid-induced leucine zipper (GILZ)-mediated immunosuppression. GILZ expression was low in dormant cell-derived cultures, and re-expression of GILZ inactivated FOXO3A and its downstream target, p21CIP1. The ability of dormancy-competent cells to re-enter the cell cycle increased after a second round of cellular dormancy in vivo in association with shortened tumour dormancy period and faster and more aggressive melanoma relapse. Our data indicate that future cancer treatments should be adjusted according to the stage of disease progression.

  12. Ex Lupi from Quiescence to Outburst: Exploring the LTE Approach in Modelling Blended H2O and OH Mid-Infrared Emission

    CERN Document Server

    Banzatti, A; Bruderer, S; Geers, V; Pascucci, I; Lahuis, F; Juhasz, A; Henning, T; Abraham, P

    2011-01-01

    We present a comparison of archival Spitzer spectra of the strongly variable T Tauri EX Lupi, observed before and during its 2008 outburst. We analyze the mid-infrared emission from gas-phase molecules thought to originate in a circumstellar disk. In quiescence the emission shows a forest of H2O lines, highly excited OH lines, and the Q branches of the organics C2H2, HCN, and CO2, similar to the emission observed toward several T Tauri systems. The outburst emission shows instead remarkable changes: H2O and OH line fluxes increase, new OH, H2, and HI transitions are detected, and organics are no longer seen. We adopt a simple model of a single-temperature slab of gas in local thermal equilibrium, a common approach for molecular analyses of Spitzer spectra, and derive the excitation temperature, column density, and emitting area of H2O and OH. We show how model results strongly depend on the selection of emission lines fitted, and that spectrally-resolved observations are essential for a correct interpretation...

  13. Fruit Exocarp Phenols in Relation to Quiescence and Development of Monilinia fructicola Infections in Prunus spp.: A Role for Cellular Redox?

    Science.gov (United States)

    Lee, Miin-Huey; Bostock, Richard M

    2007-03-01

    ABSTRACT Monilinia fructicola causes brown rot of Prunus species and usually remains quiescent on immature fruit but reactivates when fruit are mature. The dihydroxycinnamates caffeic acid and its quinate ester, chlorogenic acid, abundant in the exocarp of peach fruit, had no effect on fungal growth but markedly inhibited the production of the cell wall degrading enzymes polygalacturonase and cutinase in M. fructicola cultures. This inhibition was related to changes in the electrochemical redox potentials of the cultures, as measured with a redox electrode. Fungal culture filtrates had lower electrochemical redox potentials when the growth medium contained caffeic acid than in caffeic acid-free medium. Levels of total intracellular glutathione, the reduced form of which serves as a major cellular antioxidant, increased significantly in M. fructicola cells in response to external caffeic acid. The presence of caffeic acid, chlorogenic acid, or reduced glutathione in conidial suspensions of M. fructicola did not inhibit germination on flower petals and fruit, but inhibited appressorium formation from germinated conidia and subsequent brown rot lesion development. These results suggest that intracellular antioxidant levels in the pathogen can be influenced by phenols present in host tissue and that changes in the redox environment may influence gene expression and differentiation of structures associated with infection by the pathogen. The possible relationship of host phenols to quiescence and subsequent development of M. fructicola infections is discussed.

  14. A Clean Sightline to Quiescence: Multiwavelength Observations of the High Galactic Latitude Black Hole X-ray Binary Swift J1357.2-0933

    CERN Document Server

    Plotkin, Richard M; Jonker, Peter G; Miller-Jones, James C A; Homan, Jeroen; Munoz-Darias, Teo; Markoff, Sera; Padilla, Montserrat Armas; Fender, Rob; Rushton, Anthony P; Russell, David M; Torres, Manuel A P

    2015-01-01

    We present coordinated multiwavelength observations of the high Galactic latitude (b=+50 deg) black hole X-ray binary (XRB) J1357.2-0933 in quiescence. Our broadband spectrum includes strictly simultaneous radio and X-ray observations, and near-infrared, optical, and ultraviolet data taken 1-2 days later. We detect Swift J1357.2-0933 at all wavebands except for the radio (f_5GHz < 3.9 uJy/beam). Given current constraints on the distance (2.3-6.3 kpc), its 0.5-10 keV X-ray flux corresponds to an Eddington ratio Lx/Ledd = 4e-9 -- 3e-8 (assuming a black hole mass of 10 Msun). The broadband spectrum is dominated by synchrotron radiation from a relativistic population of outflowing thermal electrons, which we argue to be a common signature of short-period quiescent BHXBs. Furthermore, we identify the frequency where the synchrotron radiation transitions from optically thick-to-thin (approximately 2-5e14 Hz, which is the most robust determination of a 'jet break' for a quiescent BHXB to date. Our interpretation ...

  15. Ninety million years of orogenesis, 250 million years of quiescence and further orogenesis with no change in PT: Significance for the role of deformation in porphyroblast growth

    Indian Academy of Sciences (India)

    A A Shah; T H Bell

    2012-12-01

    In situ dating of monazite grains preserved as inclusions within foliations defining FIAs (foliation inflection/intersection axes preserved within porphyroblasts) contained within garnet, staurolite, andalusite and cordierite porphyroblasts provides a chronology of ages that matches the FIA succession for the Big Thompson region of the northern Colorado Rocky Mountains. FIA sets 1, 2 and 3 trending NE–SW, E–W and SE–NW were formed at 1760.5 ± 9.7, 1719.7 ± 6.4 and 1674 ± 11± Ma, respectively. For three samples where garnet first grew during just one of each of these FIAs, the intersection of Ca, Mg, and Fe isopleths in their cores indicate that these rocks never got above 4 kbars throughout the Colorado Orogeny. Furthermore, they remained around approximately the same depth for ∼250 million years to the onset of the younger Berthoud Orogeny at 1415 ± 16 Ma when the pressure decreased slightly as porphyroblasts formed with inclusion trails preserving FIA set 4 trending NNE–SSW. No porphyroblast growth occurred during the intervening ∼250 million years of quiescence, even though the PT did not change over this period. This confirms microstructural evidence gathered over the past 25 years that crenulation deformation at the scale of a porphyroblast is required for reactions to re-initiate and enable further growth.

  16. Reverse Engineering Malicious Applications

    Directory of Open Access Journals (Sweden)

    Ioan Cristian Iacob

    2015-06-01

    Full Text Available Detecting new and unknown malware is a major challenge in today’s software. Security profession. A lot of approaches for the detection of malware using data mining techniques have already been proposed. Majority of the works used static features of malware. However, static detection methods fall short of detecting present day complex malware. Although some researchers proposed dynamic detection methods, the methods did not use all the malware features. In this work, an approach for the detection of new and unknown malware was proposed and implemented. Each sample was reverse engineered for analyzing its effect on the operating environment and to extract the static and behavioral features. 

  17. Measurement of Reversed Extension Flow using the Filament Stretch Rheometer

    DEFF Research Database (Denmark)

    Rasmussen, Henrik K.; Skov, Anne Ladegaard; Nielsen, Jens Kromann;

    2008-01-01

    The measurement of material functions with reversed extension flow is demonstrated using the Filament Stretching Rheometer (FSR). This includes startup of uniaxial elongational flow (potentially until steady state) followed by biaxial squeezing, and large amplitude oscillatory elongation (LAOE). ...

  18. A gaussian model for simulated geomagnetic field reversals

    Science.gov (United States)

    Wicht, Johannes; Meduri, Domenico G.

    2016-10-01

    Field reversals are the most spectacular events in the geomagnetic history but remain little understood. Here we explore the dipole behaviour in particularly long numerical dynamo simulations to reveal statistically significant conditions required for reversals and excursions to happen. We find that changes in the axial dipole moment behaviour are crucial while the equatorial dipole moment plays a negligible role. For small Rayleigh numbers, the axial dipole always remains strong and stable and obeys a clearly Gaussian probability distribution. Only when the Rayleigh number is increased sufficiently the axial dipole can reverse and its distribution becomes decisively non-Gaussian. Increased likelihoods around zero indicate a pronounced lingering in a new low dipole moment state. Reversals and excursions can only happen when axial dipole fluctuations are large enough to drive the system from the high dipole moment state assumed during stable polarity epochs into the low dipole moment state. Since it is just a matter of chance which polarity is amplified during dipole recovery, reversals and grand excursions, i.e. excursions during which the dipole assumes reverse polarity, are equally likely. While the overall reversal behaviour seems Earth-like, a closer comparison to palaeomagnetic findings suggests that the simulated events last too long and that grand excursions are too rare. For a particularly large Ekman number we find a second but less Earth-like type of reversals where the total field decays and recovers after a certain time.

  19. Reversibly Bistable Flexible Electronics

    KAUST Repository

    Alfaraj, Nasir

    2015-05-01

    Introducing the notion of transformational silicon electronics has paved the way for integrating various applications with silicon-based, modern, high-performance electronic circuits that are mechanically flexible and optically semitransparent. While maintaining large-scale production and prototyping rapidity, this flexible and translucent scheme demonstrates the potential to transform conventionally stiff electronic devices into thin and foldable ones without compromising long-term performance and reliability. In this work, we report on the fabrication and characterization of reversibly bistable flexible electronic switches that utilize flexible n-channel metal-oxide-semiconductor field-effect transistors. The transistors are fabricated initially on rigid (100) silicon substrates before they are peeled off. They can be used to control flexible batches of light-emitting diodes, demonstrating both the relative ease of scaling at minimum cost and maximum reliability and the feasibility of integration. The peeled-off silicon fabric is about 25 µm thick. The fabricated devices are transferred to a reversibly bistable flexible platform through which, for example, a flexible smartphone can be wrapped around a user’s wrist and can also be set back to its original mechanical position. Buckling and cyclic bending of such host platforms brings a completely new dimension to the development of flexible electronics, especially rollable displays.

  20. Fundamentals of reversible flowchart languages

    DEFF Research Database (Denmark)

    Yokoyama, Tetsuo; Axelsen, Holger Bock; Glück, Robert

    2016-01-01

    . Although reversible flowcharts are superficially similar to classical flowcharts, there are crucial differences: atomic steps are limited to locally invertible operations, and join points require an explicit orthogonalizing conditional expression. Despite these constraints, we show that reversible......Abstract This paper presents the fundamentals of reversible flowcharts. They are intended to naturally represent the structure and control flow of reversible (imperative) programming languages in a simple computation model, in the same way classical flowcharts do for conventional languages......, structured reversible flowcharts are as expressive as unstructured ones, as shown by a reversible version of the classic Structured Program Theorem. We illustrate how reversible flowcharts can be concretized with two example programming languages, complete with syntax and semantics: a low-level unstructured...

  1. Reversible posterior leukoencephalopathy syndrome

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Eun Ja; Yu, Won Jong; Ahn, Kook Jin; Jung, So Lyung; Lee, Yeon Soo; Kim, Ji Chang; Kang, Si Won [The Catholic Univ. of Korea, Taejon (Korea, Republic of); Song, Chang Joon [Chungnam National Univ. School of Medicine, Cheonju (Korea, Republic of); Song, Soon-Young; Koo, Ja Hong [Kwandong Univ. College of Medicine, Myungji Hospital, Seoul (Korea, Republic of); Kim, Man Deuk [College of Medicine Pochon CHA Univ., Seoul (Korea, Republic of)

    2001-10-01

    To review reversible posterior leukoencephalopathy syndrome. We reviewed 22 patients (M:F=3:19; age, 17-46 years) with the characteristic clinical and imaging features of reversible posterior leukoencephalopathy syndrome. All underwent brain MRI, and in three cases both CT and MRI were performed. In one, MRA was obtained, and in eleven, follow-up MR images were obtained. We evaluated the causes of this syndrome, its clinical manifestations, and MR findings including the locations of lesions, the presence or absence of contrast enhancement, and the changes seen at follow-up MRI. Of the 22 patients, 13 had eclampsia (six during pregnancy and seven during puerperium). Four were receiving immunosuppressive therapy (three, cyclosporine ; one, FK 506). Four suffered renal failure and one had complicated migraine. The clinical manifestations included headache (n=12), visual disturbance (n=13), seizure (n=15), focal neurologic sign (n=3), and altered mental status (n=2). Fifteen patients had hypertension and the others normotension. MRI revealed that lesions were bilateral (n=20) or unilateral (n=2). In all patients the lesion was found in the cortical and subcortical areas of the parieto-occipital lobes ; other locations were the basal ganglia (n=9), posterior temporal lobe (n=8), frontal lobe (n=5), cerebellum (n=5), pons (n=2), and thalamus (n=1). All lesions were of high signal intensity on T2-weighted images, and of iso to low intensity on T1-weighted images. One was combined with acute hematoma in the left basal ganglia. In eight of 11 patients who underwent postcontrast T1-weighted MRI, there was no definite enhancement ; in one, enhancement was mild, and in tow, patchy. CT studies showed low attenuation, and MRA revealed mild vasospasm. The symptoms of all patients improved. Follow-up MRI in nine of 11 patients depicted complete resolution of the lesions ; in two, small infarctions remained but the extent of the lesions had decreased. Reversible posterior

  2. Simultaneous Constraints on the Mass and Radius of Aql X-1 from Quiescence and X-Ray Burst Observations

    Science.gov (United States)

    Li, Zhaosheng; Falanga, Maurizio; Chen, Li; Qu, Jinlu; Xu, Renxin

    2017-08-01

    The measurement of neutron star mass and radius is one of the most direct ways to distinguish between various dense matter equations of state. The mass and radius of accreting neutron stars hosted in low-mass X-ray binaries can be constrained by several methods, including photospheric radius expansion from type I X-ray bursts and from quiescent spectra. In this paper, we apply for the first time these two methods simultaneously to constrain the mass and radius of Aql X-1. The quiescent spectra from Chandra and XMM-Newton, and photospheric radius expansion bursts from RXTE are used. The determination of the mass and radius of Aql X-1 is also used to verify the consistency between the two methods and to narrow down the uncertainties of the neutron star mass and radius. It is found that the distance to Aql X-1 should be in the range of 4.0-5.75 kpc, based on the overlapping confidence regions between photospheric radius expansion burst and quiescent spectra methods. In addition, we show that the mass and radius determined for the compact star in Aql X-1 are compatible with strange star equations of state and conventional neutron star models.

  3. Reverse photoacoustic standoff spectroscopy

    Science.gov (United States)

    Van Neste, Charles W [Kingston, TN; Senesac, Lawrence R [Knoxville, TN; Thundat, Thomas G [Knoxville, TN

    2011-04-12

    A system and method are disclosed for generating a reversed photoacoustic spectrum at a greater distance. A source may emit a beam to a target and a detector measures signals generated as a result of the beam being emitted on the target. By emitting a chopped/pulsed light beam to the target, it may be possible to determine the target's optical absorbance by monitoring the intensity of light collected at the detector at different wavelengths. As the wavelength of light is changed, the target may absorb or reject each optical frequency. Rejection may increase the intensity at the sensing element and absorption may decrease the intensity. Accordingly, an identifying spectrum of the target may be made with the intensity variation of the detector as a function of illuminating wavelength.

  4. Is Computation Reversible?

    CERN Document Server

    Parker, M C; Parker, Michael C.; Walker, Stuart D.

    2004-01-01

    Recent investigations into the physical nature of information and fundamental limits to information transmission have revealed questions such as the possibility of superluminal data transfer or not; and whether reversible computation (information processing) is feasible. In some respects these uncertainties stem from the determination of whether information is inherent in points of non-analyticity (discontinuities) or smoother functions. The close relationship between information and entropy is also well known, e.g. Brillouin's concept of negentropy (negative entropy) as a measure for information. Since the leading edge of a step-discontinuity propagates in any dispersive medium at the speed of light in vacuum as a precursor to the main body of the dispersed pulse, we propose in this paper to treat information as being intrinsic to points of non-analyticity (discontinuities). This allows us to construct a theory addressing these dilemmas in a fashion consistent with causality, and the fundamental laws of ther...

  5. Reverse Osmosis Optimization

    Energy Technology Data Exchange (ETDEWEB)

    None

    2013-08-01

    This technology evaluation was prepared by Pacific Northwest National Laboratory on behalf of the U.S. Department of Energy’s Federal Energy Management Program (FEMP). The technology evaluation assesses techniques for optimizing reverse osmosis (RO) systems to increase RO system performance and water efficiency. This evaluation provides a general description of RO systems, the influence of RO systems on water use, and key areas where RO systems can be optimized to reduce water and energy consumption. The evaluation is intended to help facility managers at Federal sites understand the basic concepts of the RO process and system optimization options, enabling them to make informed decisions during the system design process for either new projects or recommissioning of existing equipment. This evaluation is focused on commercial-sized RO systems generally treating more than 80 gallons per hour.

  6. Reverse Osmosis Optimization

    Energy Technology Data Exchange (ETDEWEB)

    McMordie Stoughton, Kate; Duan, Xiaoli; Wendel, Emily M.

    2013-08-26

    This technology evaluation was prepared by Pacific Northwest National Laboratory on behalf of the U.S. Department of Energy’s Federal Energy Management Program (FEMP). ¬The technology evaluation assesses techniques for optimizing reverse osmosis (RO) systems to increase RO system performance and water efficiency. This evaluation provides a general description of RO systems, the influence of RO systems on water use, and key areas where RO systems can be optimized to reduce water and energy consumption. The evaluation is intended to help facility managers at Federal sites understand the basic concepts of the RO process and system optimization options, enabling them to make informed decisions during the system design process for either new projects or recommissioning of existing equipment. This evaluation is focused on commercial-sized RO systems generally treating more than 80 gallons per hour.¬

  7. Multiple stimulus reversible hydrogels

    Science.gov (United States)

    Gutowska, Anna; Krzyminski, Karol J.

    2003-12-09

    A polymeric solution capable of gelling upon exposure to a critical minimum value of a plurality of environmental stimuli is disclosed. The polymeric solution may be an aqueous solution utilized in vivo and capable of having the gelation reversed if at least one of the stimuli fall below, or outside the range of, the critical minimum value. The aqueous polymeric solution can be used either in industrial or pharmaceutical environments. In the medical environment, the aqueous polymeric solution is provided with either a chemical or radioisotopic therapeutic agent for delivery to a specific body part. The primary advantage of the process is that exposure to one environmental stimuli alone will not cause gelation, thereby enabling the therapeutic agent to be conducted through the body for relatively long distances without gelation occurring.

  8. Transport Physics in Reversed Shear Plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Levinton, F.M.; Batha, S.H. [Fusion Physics and Technology, Inc., Torrance, CA (United States); Beer, M.A.; Bell, M.G.; Budny, R.V.; Efthimion, P.C.; Mazzucato, E.; Nazikian, R.; Park, H.K.; Ramsey, A.T.; Schmidt, G.L.; Scott, S.D.; Synakowski, E.J.; Taylor, G.; Von Goeler, S.; Zarnstorff, M.C. [Princeton University, NJ (United States). Plasma Physics Laboratory; Bush, C.E. [Oak Ridge National Lab., TN (United States)

    1997-12-31

    Reversed magnetic shear is considered a good candidate for improving the tokamak concept because it has the potential to stabilize MHD instabilities and reduce particle and energy transport. With reduced transport the high pressure gradient would generate a strong off-axis bootstrap current and could sustain a hollow current density profile. Such a combination of favorable conditions could lead to an attractive steady-state tokamak configuration. Indeed, a new tokamak confinement regime with reversed magnetic shear has been observed on the Tokamak Fusion Test Reactor (TFTR) where the particle, momentum, and ion thermal diffusivities drop precipitously, by over an order of magnitude. The particle diffusivity drops to the neoclassical level and the ion thermal diffusivity drops to much less than the neoclassical value in the region with reversed shear. This enhanced reversed shear (ERS) confinement mode is characterized by an abrupt transition with a large rate of rise of the density in the reversed shear region during neutral beam injection, resulting in nearly a factor of three increase in the central density to 1.2 X 10(exp 20) cube m. At the same time the density fluctuation level in the reversed shear region dramatically decreases. The ion and electron temperatures, which are about 20 keV and 7 keV respectively, change little during the ERS mode. The transport and transition into and out of the ERS mode have been studied on TFTR with plasma currents in the range 0.9-2.2 MA, with a toroidal magnetic field of 2.7-4.6 T, and the radius of the q(r) minimum, q{sub min}, has been varied from r/a = 0.35 to 0.55. Toroidal field and co/counter neutral beam injection toroidal rotation variations have been used to elucidate the underlying physics of the transition mechanism and power threshold of the ERS mode.

  9. A Reversible Processor Architecture and its Reversible Logic Design

    DEFF Research Database (Denmark)

    Thomsen, Michael Kirkedal; Axelsen, Holger Bock; Glück, Robert

    2012-01-01

    We describe the design of a purely reversible computing architecture, Bob, and its instruction set, BobISA. The special features of the design include a simple, yet expressive, locally-invertible instruction set, and fully reversible control logic and address calculation. We have designed...... an architecture with an ISA that is expressive enough to serve as the target for a compiler from a high-level structured reversible programming language. All-in-all, this paper demonstrates that the design of a complete reversible computing architecture is possible and can serve as the core of a programmable...

  10. Sub1 and Maf1, two effectors of RNA polymerase III, are involved in the yeast quiescence cycle.

    Directory of Open Access Journals (Sweden)

    Joël Acker

    Full Text Available Sub1 and Maf1 exert an opposite effect on RNA polymerase III transcription interfering with different steps of the transcription cycle. In this study, we present evidence that Sub1 and Maf1 also exhibit an opposite role on yeast chronological life span. First, cells lacking Sub1 need more time than wild type to exit from resting and this lag in re-proliferation is correlated with a delay in transcriptional reactivation. Second, our data show that the capacity of the cells to properly establish a quiescent state is impaired in the absence of Sub1 resulting in a premature death that is dependent on the Ras/PKA and Tor1/Sch9 signalling pathways. On the other hand, we show that maf1Δ cells are long-lived mutant suggesting a connection between Pol III transcription and yeast longevity.

  11. Dimensioning of reverse osmosis installation driven by photovoltaic panels: an experience of Coite - Pedreiras, Ceara State, Brazil; Dimensionamento de uma instalacao de osmose reversa acionada por paineis fotovoltaicos: a experiencia de Coite - Pedreiras

    Energy Technology Data Exchange (ETDEWEB)

    Carvalho, Paulo Cesar Marques de; Oliveira, Ricardo Gildo Vieira de [Ceara Univ., Fortaleza, CE (Brazil). Dept. de Engenharia Eletrica. Grupo de Processamento de Energia e Controle]. E-mail: carvalho@dee.ufc.br; ricardogildo@bol.com.br; Freire, Cristiano Augusto da Silva [ARCE, Agencia Reguladora de Servicos Publicos Delegados do Estado do Ceara, Fortaleza, CE (Brazil)]. E-mail: cristiano@arce.ce.gov.br

    2002-07-01

    The paper evaluates the dimensioning of a photovoltaic generator used for supplying electric power to a battery bank coupled to a reverse osmosis installation. The evaluation is focused on site data collected and stored by a data acquisition system. The dimensioning evaluation nis performed considering that not all the solar energy entering in panes is converted to electric power due to the using of charge control between the generator and the battery bank.

  12. 颠倒睡眠状态调制心率变异性信号的功率谱和基本尺度熵分析%Analysis on p ower sp ectrum and base-scale entropy for heart rate variability signals mo dulated by reversed sleep state

    Institute of Scientific and Technical Information of China (English)

    刘大钊; 王俊; 李锦; 李瑜; 徐文敏; 赵筱

    2014-01-01

    心率变异性(HRV)信号能够提供心脏活动状态的重要信息。通过建立颠倒睡眠模型,联合功率谱和基本尺度熵方法分析颠倒睡眠状态下24 h的HRV信号,研究颠倒睡眠对自主神经相互作用以及HRV信号混沌强度的调制。结果表明,颠倒睡眠导致自主神经在昼夜间的活动节律发生颠倒,基本尺度熵在昼夜的变化趋势也随之发生逆转,因此HRV信号的混沌强度与自主神经的相互作用密切相关,进一步研究两者之间的关系发现: HRV信号的混沌强度与交感神经的调制强度正相关,与迷走神经的调制强度负相关。%Heart rate variability(HRV) signals can provide the important information about the active state of heart. To set up a reversed sleep model, then, we analyze the 24-hours HRV signals modulated by the reversed sleep state using the power spectrum and base-scale entropy method, and study the effect of the interaction of autonomic nerve system and the chaotic intensity of HRV signals in the case of reversed sleep. Results show that because of the reversed sleep state, the activity rhythm of autonomic nerve is contrary to that in normal state. The variational trend of base-scale entropy is corresponding to that reversed in day and night. This means that the chaotic intensity of HRV signals is closely related to the reaction of autonomic nerve system. In further researches, it is found that the chaotic intensity of HRV signals is in positive correlation with the modulation intensity of sympathetic nerve, but in negative correlation with the modulation intensity of vagus.

  13. The middle-long term prediction of the February 3, 1996 Lijiang earthquake (M S=7) by the ``criterion of activity in quiescence''

    Science.gov (United States)

    Zeng-Jian, Guo; Bao-Yan, Qin

    2000-07-01

    Earthquake activities in history are characterized by active and quiet periods. In the quiet period, the place where earthquake M S≥6 occurred means more elastic energy store and speedy energy accumulation there. When an active period of big earthquake activity appeared in wide region, in the place where earthquake (M S≥6) occurred in the past quiet period, the big earthquake with magnitude of 7 or more often occur there. We call the above-mentioned judgement for predicting big earthquake the “criterion of activity in quiescence”. The criterion is relatively effective for predicting location of big earthquake. In general, error of predicting epicenter is no more than 100 km. According to the criterion, we made successfully a middle-term prediction on the 1996 Lijiang earthquake in Yunnan Province, the error of predicted location is about 50 km. Besides, the 1994 Taiwan strait earthquake (M S=7.3), the 1995 Yunnan-Myanmar boundary earthquake (M S=7.2) and the Mani earthquake (M S=7.9) in north Tibet are accordant with the retrospective predictions by the “criterion of activity in quiescence”. The windows of “activity in quiescence” identified statistically by us are 1940 1945, 1958 1961 and 1979 1986. Using the “criterion of activity in quiescence” to predict big earthquake in the mainland of China, the earthquake defined by “activity in quiescence” has magnitude of 6 or more; For the Himalayas seismic belt, the Pacific seismic belt and the north-west boundary seismic belt of Xinjiang, the earthquake defined by “activity in quiescence” has magnitude of 7, which is corresponding to earthquake with magnitude of much more than 7 in future. For the regions where there are not tectonically and historically a possibility of occurring big earthquake (M S=7), the criterion of activity in quiescence is not effective.

  14. Retinoblastoma protein (pRb), but not p107 or p130, is required for maintenance of enterocyte quiescence and differentiation in small intestine.

    Science.gov (United States)

    Guo, Jun; Longshore, Shannon; Nair, Rajalakshmi; Warner, Brad W

    2009-01-01

    The function of retinoblastoma protein (pRb) in the regulation of small intestine epithelial cell homeostasis has been challenged by several groups using various promoter-based Cre transgenic mouse lines. Interestingly, different pRb deletion systems yield dramatically disparate small intestinal phenotypes. These findings confound the function of pRb in this dynamic tissue. In this study, Villin-Cre transgenic mice were crossed with Rb (flox/flox) mice to conditionally delete pRb protein in small intestine enterocytes. We discovered a novel hyperplasia phenotype as well as ectopic cell cycle reentry within villus enterocytes in the small intestine. This phenotype was not seen in other pRb family member (p107 or p130) null mice. Using a newly developed crypt/villus isolation method, we uncovered that expression of pRb was undetectable, whereas proliferating cell nuclear antigen, p107, cyclin E, cyclin D3, Cdk2, and Cdc2 were dramatically increased in pRb-deficient villus cells. Cyclin A, cyclin D1, cyclin D2, and Cdk4/6 expression was not affected by absent pRb expression. pRb-deficient villus cells appeared capable of progressing to mitosis but with higher rates of apoptosis. However, the cycling villus enterocytes were not completely differentiated as gauged by significant reduction of intestinal fatty acid-binding protein expression. In summary, pRb, but not p107 or p130, is required for maintaining the postmitotic villus cell in quiescence, governing the expression of cell cycle regulatory proteins, and completing of absorptive enterocyte differentiation in the small intestine.

  15. ULTRACAM observations of the black hole X-ray transient XTE J1118+480 in quiescence

    CERN Document Server

    Shahbaz, T; Marsh, T R; Casares, J; Zurita, C; Charles, P A; Haswell, C A; Hynes, R I

    2005-01-01

    We present high time-resolution multicolour observations of the quiescent soft X-ray transient XTE J1118+480 obtained with ULTRACAM. Superimposed on the double-humped continuum g' and i'-band lightcurves are rapid flare events which typically last a few minutes. The power density spectrum of the lightcurves can be described by a broken power-law model with a break frequency at ~2 mHz or a power-law model plus a broad quasi-periodic oscillation (QPO) at ~2 mHz. In the context of the cellular-automaton we estimate the size of the quiescent advection-dominated flow (ADAF) region to be ~10^4 Schwarzschild radii, similar to that observed in other quiescent black hole X-ray transients, suggesting the same underlying physics. The similarites between the low/hard and quiescent state PDS suggest a similar origin for the optical and X-ray variability, most likely from regions at/near the ADAF.

  16. Apparent Reversal of Molecular Orbitals Reveals Entanglement

    Science.gov (United States)

    Yu, Ping; Kocić, Nemanja; Repp, Jascha; Siegert, Benjamin; Donarini, Andrea

    2017-08-01

    The frontier orbital sequence of individual dicyanovinyl-substituted oligothiophene molecules is studied by means of scanning tunneling microscopy. On NaCl /Cu (111 ) , the molecules are neutral, and the two lowest unoccupied molecular states are observed in the expected order of increasing energy. On NaCl /Cu (311 ) , where the molecules are negatively charged, the sequence of two observed molecular orbitals is reversed, such that the one with one more nodal plane appears lower in energy. These experimental results, in open contradiction with a single-particle interpretation, are explained by a many-body theory predicting a strongly entangled doubly charged ground state.

  17. 49 CFR 230.89 - Reverse gear.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Reverse gear. 230.89 Section 230.89 Transportation... Reversing Gear § 230.89 Reverse gear. (a) General provisions. Reverse gear, reverse levers, and quadrants... quadrant. Proper counterbalance shall be provided for the valve gear. (b) Air-operated power reverse...

  18. Aspiration Level and the Reversal of the Preference Reversal Phenomenon.

    Science.gov (United States)

    1986-09-01

    American Economic Review , 69, 623- 638...Grether, D. M., & Plott, C. R. (1982). Economic theory of choice and the preference reversal phenomenon: Reply. The American Economic Review , 72, 575. Har...34 - . • . ...... ., .. . -. -.,- ... , .. ... - ., . . . . .. . ... . . . . . . . *~~~7 T, W.. 1 d~ I t Y ~ VVW ~ Page 26 1 loomes, G., & Sugden, R. (1983). A rationale for preference reversal. The American Economic Review ,

  19. Design of Reversible Sequential Circuit Using Reversible Logic Synthesis

    Directory of Open Access Journals (Sweden)

    Md. Belayet Ali

    2011-12-01

    Full Text Available Reversible logic is one of the most vital issue at present time and it has different areas for its application,those are low power CMOS, quantum computing, nanotechnology, cryptography, optical computing, DNA computing, digital signal processing (DSP, quantum dot cellular auto meta, communication, computer graphics. It is not possible to realize quantum computing without implementation of reversible logic. The main purposes of designing reversible logic are to decrease quantum cost, depth of the circuits and the number of garbage outputs. In this paper, we have proposed a new reversible gate. And we have designed RS flip flop and D flip flop by using our proposed gate and Peres gate. The proposed designs are better than the existing proposed ones in terms of number of reversible gates and garbage outputs. So, this realization is more efficient and less costly than other realizations.

  20. Design of Reversible Sequential Circuit Using Reversible Logic Synthesis

    Directory of Open Access Journals (Sweden)

    Md. Mosharof Hossin

    2012-01-01

    Full Text Available Reversible logic is one of the most vital issue at present time and it has different areas for its application, those are low power CMOS, quantum computing, nanotechnology, cryptography, optical computing, DNA computing, digital signal processing (DSP, quantum dot cellular automata, communication, computer graphics. It is not possible to realize quantum computing without implementation of reversible logic. The main purposes of designing reversible logic are to decrease quantum cost, depth of the circuits and the number of garbage outputs. In this paper, we have proposed a new reversible gate. And we have designedRS flip flop and D flip flop by using our proposed gate and Peres gate. The proposed designs are better than the existing proposed ones in terms of number of reversible gates and garbage outputs. So, this realization is more efficient and less costly than other realizations.

  1. Reversible hypothyroidism and Whipple's disease

    Directory of Open Access Journals (Sweden)

    Tran Huy A

    2006-05-01

    Full Text Available Abstract Background The major cause of primary hypothyroidism is autoimmune mediated with progressive and permanent destruction of the thyroid gland resulting in life-long replacement therapy. Treatable and reversible hypothyroidism is unusual and here forth is such a case due to infection of the thyroid gland with Tropheryma whippleii, Whipple disease. Case presentation A 45 year-old female presented with symptoms and signs consistent with primary hypothyroidism, which was also confirmed biochemically. Her response to thyroxine replacement therapy was poor however, requiring a significantly elevated amount. Further investigation revealed the presence of Whipple's disease involving the gastrointestinal trace and possibly the thyroid gland. Her thyroxine requirement decreased drastically following appropriate antimicrobial therapy for Whipple's disease to the extent that it was ceased. Thyrotropin releasing hormone testing in the steady state suggested there was diminished thyroid reserve due to Whipple's disease. Conclusion This is the first ante-mortem case report studying the possible involvement of the thyroid gland by Whipple's disease. Despite the normalization of her thyroid function test biochemically after antibiotic therapy, there is diminished thyroid reserve thus requiring close and regular monitoring.

  2. Dynamics of a bacterial flagellum under reverse rotation

    CERN Document Server

    Adhyapak, Tapan Chandra

    2016-01-01

    To initiate tumbling of an E. coli, one of the helical flagella reverses its sense of rotation. It then transforms from its normal form first to the transient semicoiled state and subsequently to the curly-I state. The dynamics of polymorphism is effectively modeled by describing flagellar elasticity through an extended Kirchhoff free energy. However, the complete landscape of the free energy remains undetermined because the ground state energies of the polymorphic forms are not known. We investigate how variations in these ground state energies affect the dynamics of a reversely rotated flagellum of a swimming bacterium. We find that the flagellum exhibits a number of distinct dynamical states and comprehensively summarize them in a state diagram. As a result, we conclude that tuning the landscape of the extended Kirchhoff free energy alone cannot generate the intermediate full-length semicoiled state. However, our model suggests an ad hoc method to realize the sequence of polymorphic states as observed for ...

  3. Fluctuation patterns and conditional reversibility in nonequilibrium systems

    CERN Document Server

    Gallavotti, G

    1997-01-01

    Fluctuations of observables as functions of time, or "fluctuation patterns", are studied in a chaotic microscopically reversible system that has irreversibly reached a nonequilibrium stationary state. Supposing that during a certain, long enough, time interval the average entropy creation rate has a value $s$ and that during another time interval of the same length it has value $-s$ then we show that the relative probabilities of fluctuation patterns in the first time interval are the same as those of the reversed patterns in the second time interval. The system is ``conditionally reversible'' or irreversibility in a reversible system is "driven" by the entropy creation: while a very rare fluctuation happens to change the sign of the entropy creation rate it also happens that the time reversed fluctuations of all other observables acquire the same relative probability of the corresponding fluctuations in presence of normal entropy creation. A mathematical proof is sketched.

  4. Elastomers with Reversible Nanoporosity

    DEFF Research Database (Denmark)

    Szewczykowski, Piotr Przemyslaw; Andersen, K.; Schulte, Lars;

    2009-01-01

    An elastomer was created via cross-linking a diene block of a polyisoprene-polydimethylsiloxane (PI-PDMS) block copolymer in the ordered state of hexagonal morphology, followed by the quantitative removal of the PDMS component. The elastomer material collapsed following etching of the PDMS...

  5. Enzymatic reactions in reversed micelles

    NARCIS (Netherlands)

    Hilhorst, M.H.

    1984-01-01

    It has been recognised that enzymes in reversed micelles have potential for application in chemical synthesis. Before these expectations will be realised many problems must be overcome. This thesis deals with some of them.In Chapter 1 the present knowledge about reversed micelles and micellar enzymo

  6. Enzyme recovery using reversed micelles.

    NARCIS (Netherlands)

    Dekker, M.

    1990-01-01

    The objective of this study was to develop a liquid-liquid extraction process for the recovery of extracellular enzymes. The potentials of reaching this goal by using reversed micelles in an organic solvent have been investigated.Reversed micelles are aggregates of surfactant molecules containing an

  7. Model of reversible vesicular transport with exclusion

    Science.gov (United States)

    Bressloff, Paul C.; Karamched, Bhargav R.

    2016-08-01

    A major question in neurobiology concerns the mechanics behind the motor-driven transport and delivery of vesicles to synaptic targets along the axon of a neuron. Experimental evidence suggests that the distribution of vesicles along the axon is relatively uniform and that vesicular delivery to synapses is reversible. A recent modeling study has made explicit the crucial role that reversibility in vesicular delivery to synapses plays in achieving uniformity in vesicle distribution, so called synaptic democracy (Bressloff et al 2015 Phys. Rev. Lett. 114 168101). In this paper we generalize the previous model by accounting for exclusion effects (hard-core repulsion) that may occur between molecular motor-cargo complexes (particles) moving along the same microtubule track. The resulting model takes the form of an exclusion process with four internal states, which distinguish between motile and stationary particles, and whether or not a particle is carrying vesicles. By applying a mean field approximation and an adiabatic approximation we reduce the system of ODEs describing the evolution of occupation numbers of the sites on a 1D lattice to a system of hydrodynamic equations in the continuum limit. We find that reversibility in vesicular delivery allows for synaptic democracy even in the presence of exclusion effects, although exclusion does exacerbate nonuniform distributions of vesicles in an axon when compared with a model without exclusion. We also uncover the relationship between our model and other models of exclusion processes with internal states.

  8. Insulin-like growth factor 1 receptor and p38 mitogen-activated protein kinase signals inversely regulate signal transducer and activator of transcription 3 activity to control human dental pulp stem cell quiescence, propagation, and differentiation.

    Science.gov (United States)

    Vandomme, Jerome; Touil, Yasmine; Ostyn, Pauline; Olejnik, Cecile; Flamenco, Pilar; El Machhour, Raja; Segard, Pascaline; Masselot, Bernadette; Bailliez, Yves; Formstecher, Pierre; Polakowska, Renata

    2014-04-15

    Dental pulp stem cells (DPSCs) remain quiescent until activated in response to severe dental pulp damage. Once activated, they exit quiescence and enter regenerative odontogenesis, producing reparative dentin. The factors and signaling molecules that control the quiescence/activation and commitment to differentiation of human DPSCs are not known. In this study, we determined that the inhibition of insulin-like growth factor 1 receptor (IGF-1R) and p38 mitogen-activated protein kinase (p38 MAPK) signaling commonly activates DPSCs and promotes their exit from the G0 phase of the cell cycle as well as from the pyronin Y(low) stem cell compartment. The inhibition of these two pathways, however, inversely determines DPSC fate. In contrast to p38 MAPK inhibitors, IGF-1R inhibitors enhance dental pulp cell sphere-forming capacity and reduce the cells' colony-forming capacity without inducing cell death. The inverse cellular changes initiated by IGF-1R and p38 MAPK inhibitors were accompanied by inverse changes in the levels of active signal transducer and activator of transcription 3 (STAT3) factor, inactive glycogen synthase kinase 3, and matrix extracellular phosphoglycoprotein, a marker of early odontoblast differentiation. Our data suggest that there is cross talk between the IGF-1R and p38 MAPK signaling pathways in DPSCs and that the signals provided by these pathways converge at STAT3 and inversely regulate its activity to maintain quiescence or to promote self-renewal and differentiation of the cells. We propose a working model that explains the possible interactions between IGF-1R and p38 MAPK at the molecular level and describes the cellular consequences of these interactions. This model may inspire further fundamental study and stimulate research on the clinical applications of DPSC in cellular therapy and tissue regeneration.

  9. What do reversible programs compute?

    DEFF Research Database (Denmark)

    Axelsen, Holger Bock; Glück, Robert

    2011-01-01

    Reversible computing is the study of computation models that exhibit both forward and backward determinism. Understanding the fundamental properties of such models is not only relevant for reversible programming, but has also been found important in other fields, e.g., bidirectional model...... transformation, program transformations such as inversion, and general static prediction of program properties. Historically, work on reversible computing has focussed on reversible simulations of irreversible computations. Here, we take the viewpoint that the property of reversibility itself should...... are not strictly classically universal, but that they support another notion of universality; we call this RTM-universality. Thus, even though the RTMs are sub-universal in the classical sense, they are powerful enough as to include a self-interpreter. Lifting this to other computation models, we propose r...

  10. Optimization of reversible sequential circuits

    CERN Document Server

    Sayem, Abu Sadat Md

    2010-01-01

    In recent years reversible logic has been considered as an important issue for designing low power digital circuits. It has voluminous applications in the present rising nanotechnology such as DNA computing, Quantum Computing, low power VLSI and quantum dot automata. In this paper we have proposed optimized design of reversible sequential circuits in terms of number of gates, delay and hardware complexity. We have designed the latches with a new reversible gate and reduced the required number of gates, garbage outputs, and delay and hardware complexity. As the number of gates and garbage outputs increase the complexity of reversible circuits, this design will significantly enhance the performance. We have proposed reversible D-latch and JK latch which are better than the existing designs available in literature.

  11. Reversed polarity patches at the CMB and geomagnetic field reversal

    Institute of Scientific and Technical Information of China (English)

    XU; Wenyao(徐文耀); WEI; Zigang(魏自刚)

    2002-01-01

    The International Geomagnetic Reference Field models (IGRF) for 1900-2000 are used to calculate the geomagnetic field distribution in the Earth' interior from the ground surface to the core-mantle boundary (CMB) under the assumption of insulated mantle. Four reversed polarity patches, as one of the most important features of the CMB field, are revealed. Two patches with +Z polarity (downward) at the southern African and the southern American regions stand out against the background of -Z polarity (upward) in the southern hemisphere, and two patches of -Z polarity at the North Polar and the northern Pacific regions stand out against the +Z background in the northern hemisphere. During the 1900-2000 period the southern African (SAF) patch has quickly drifted westward at a speed of 0.2-0.3°/a; meanwhile its area has expanded 5 times, and the magnetic flux crossing the area has intensified 30 times. On the other hand, other three patches show little if any change during this 100-year period. Extending upward, each of the reversed polarity patches at the CMB forms a chimney-shaped "reversed polarity column" in the mantle with the bottom at the CMB. The height of the SAF column has grown rapidly from 200km in 1900 to 900km in 2000. If the column grows steadily at the same rate in the future, its top will reach to the ground surface in 600-700 years. And then a reversed polarity patch will be observed at the Earth's surface, which will be an indicator of the beginning of a magnetic field reversal. On the basis of this study, one can describe the process of a geomagnetic polarity reversal, the polarity reversal may be observed firstly in one or several local regions; then the areas of these regions expand, and at the same time, other new reversed polarity regions may appear. Thus several poles may exist during a polarity reversal.

  12. Photophysical properties of pyronin dyes in reverse micelles of AOT

    Energy Technology Data Exchange (ETDEWEB)

    Bayraktutan, Tuğba; Meral, Kadem; Onganer, Yavuz, E-mail: yonganer@atauni.edu.tr

    2014-01-15

    The photophysical properties of pyronin B (PyB) and pyronin Y (PyY) in reverse micelles formed with water/sodium bis (2-ethyl-1-hexyl) sulfosuccinate (AOT)/n-heptane were investigated by UV–vis absorption, steady-state and time-resolved fluorescence spectroscopy techniques. This study was carried out a wide range of reverse micelle sizes, with hydrodynamic radii ranging from 1.85 to 9.38 nm. Significant photophysical parameters as band shifts, fluorescence quantum yields and fluorescence lifetimes were determined to understand how photophysical and spectroscopic features of the dye compounds were affected by the variation of reverse micelle sizes. In this regard, control of reverse micelle size by changing W{sub 0}, the molar ratio of water to surfactant, allowed tuning the photophysical properties of the dyes in organic solvent via reverse micelle. Non-fluorescent H-aggregates of pyronin dyes were observed for the smaller reverse micelles whereas an increase in the reverse micelle size induced an increment in the amount of dye monomers instead of dye aggregates. Thus, the fluorescence intensities of the dyes were improved by increasing W{sub 0} due to the predomination of the fluorescent dye monomers. As a result, the fluorescence quantum yields also increased. The fluorescence lifetimes of the dyes in the reverse micelles were determined by the time-resolved fluorescence decay studies. Evaluation of the fluorescence lifetimes calculated for pyronin dyes in the reverse micelles showed that the size of reverse micelle affected the fluorescence lifetimes of pyronin dyes. -- Highlights: • The photophysical properties of pyronin dyes were examined by spectroscopic techniques. • Optical properties of the dyes were tuned by changing of W{sub 0} values. • The fluorescence lifetime and quantum yield values of the dyes in reverse micelles were discussed.

  13. Sheehan syndrome with reversible dilated cardiomyopathy.

    Science.gov (United States)

    Laway, Bashir A; Alai, Mohammad S; Gojwari, Tariq; Ganie, Mohd A; Zargar, Abdul Hamid

    2010-01-01

    Cardiac abnormalities in patients with Sheehan syndrome are uncommon. A case of Sheehan syndrome with dilated cardiomyopathy is presented in whom hormone replacement with levothyroxine and prednisolone resulted in complete recovery of cardiomyopathy. A 25-year-old woman presented with lactation failure, secondary amenorrhea, features of hypothyroidism and a hypocortisol state following severe postpartum hemorrhage after her last child birth. She also had smear positive pulmonary tuberculosis. After starting antitubercular treatment, she developed shock, suggestive of hypocortisol crisis. Hormonal investigations revealed evidence of panhypopitutarism and magnetic resonance imaging revealed partial empty sella. Meanwhile echocardiography revealed evidence of dilated cardiomyopathy (DCM). The patient was given replacement therapy in the form of glucocorticoids and levothyroxine in addition to antitubercular treatment. She improved and on follow-up over a period of 7 months, the DCM completely reversed. To our knowledge this is the first report of reversible DCM in a patient with Sheehan syndrome.

  14. Optimized reversible BCD adder using new reversible logic gates

    CERN Document Server

    Bhagyalakshmi, H R

    2010-01-01

    Reversible logic has received great attention in the recent years due to their ability to reduce the power dissipation which is the main requirement in low power digital design. It has wide applications advanced computing, low power CMOS design, Optical information processing, DNA computing, bio information, quantum computation and nanotechnology. This paper presents an optimized reversible BCD adder using a new reversible gate. A comparative result is presented which shows that the proposed design is more optimized in terms of number of gates, number of garbage outputs and quantum cost than the existing designs.

  15. Fingerprinting Reverse Proxies Using Timing Analysis of TCP Flows

    Science.gov (United States)

    2013-09-01

    masking where the content is truly hosted. Reverse proxies interact over the HyperText Transfer Protocol (HTTP), which is delivered via the Transmission...where the content is truly hosted. Reverse proxies interact over the HyperText Transfer Protocol (HTTP), which is delivered via the Transmission...FSM Finite State Machine HTML Hypertext Markup Language HTTP Hypertext Transfer Protocol HTTPS Hypertext Transfer Protocol Secure ICMP Internet Control

  16. NOVEL REVERSIBLE VARIABLE PRECISION MULTIPLIER USING REVERSIBLE LOGIC GATES

    National Research Council Canada - National Science Library

    M. Saravanan; K. Suresh Manic

    2014-01-01

    .... In this study a reversible logic gate based design of variable precision multiplier is proposed which have the greater efficiency in power consumption and speed since the partial products received...

  17. Supercritical fluid reverse micelle separation

    Science.gov (United States)

    Fulton, John L.; Smith, Richard D.

    1993-01-01

    A method of separating solute material from a polar fluid in a first polar fluid phase is provided. The method comprises combining a polar fluid, a second fluid that is a gas at standard temperature and pressure and has a critical density, and a surfactant. The solute material is dissolved in the polar fluid to define the first polar fluid phase. The combined polar and second fluids, surfactant, and solute material dissolved in the polar fluid is maintained under near critical or supercritical temperature and pressure conditions such that the density of the second fluid exceeds the critical density thereof. In this way, a reverse micelle system defining a reverse micelle solvent is formed which comprises a continuous phase in the second fluid and a plurality of reverse micelles dispersed in the continuous phase. The solute material is dissolved in the polar fluid and is in chemical equilibrium with the reverse micelles. The first polar fluid phase and the continuous phase are immiscible. The reverse micelles each comprise a dynamic aggregate of surfactant molecules surrounding a core of the polar fluid. The reverse micelle solvent has a polar fluid-to-surfactant molar ratio W, which can vary over a range having a maximum ratio W.sub.o that determines the maximum size of the reverse micelles. The maximum ratio W.sub.o of the reverse micelle solvent is then varied, and the solute material from the first polar fluid phase is transported into the reverse micelles in the continuous phase at an extraction efficiency determined by the critical or supercritical conditions.

  18. Supercritical fluid reverse micelle separation

    Science.gov (United States)

    Fulton, J.L.; Smith, R.D.

    1993-11-30

    A method of separating solute material from a polar fluid in a first polar fluid phase is provided. The method comprises combining a polar fluid, a second fluid that is a gas at standard temperature and pressure and has a critical density, and a surfactant. The solute material is dissolved in the polar fluid to define the first polar fluid phase. The combined polar and second fluids, surfactant, and solute material dissolved in the polar fluid is maintained under near critical or supercritical temperature and pressure conditions such that the density of the second fluid exceeds the critical density thereof. In this way, a reverse micelle system defining a reverse micelle solvent is formed which comprises a continuous phase in the second fluid and a plurality of reverse micelles dispersed in the continuous phase. The solute material is dissolved in the polar fluid and is in chemical equilibrium with the reverse micelles. The first polar fluid phase and the continuous phase are immiscible. The reverse micelles each comprise a dynamic aggregate of surfactant molecules surrounding a core of the polar fluid. The reverse micelle solvent has a polar fluid-to-surfactant molar ratio W, which can vary over a range having a maximum ratio W[sub o] that determines the maximum size of the reverse micelles. The maximum ratio W[sub o] of the reverse micelle solvent is then varied, and the solute material from the first polar fluid phase is transported into the reverse micelles in the continuous phase at an extraction efficiency determined by the critical or supercritical conditions. 27 figures.

  19. NOVEL REVERSIBLE VARIABLE PRECISION MULTIPLIER USING REVERSIBLE LOGIC GATES

    OpenAIRE

    M. Saravanan; K. Suresh Manic

    2014-01-01

    Multipliers play a vital role in digital systems especially in digital processors. There are many algorithms and designs were proposed in the earlier works, but still there is a need and a greater interest in designing a less complex, low power consuming, fastest multipliers. Reversible logic design became the promising technologies gaining greater interest due to less dissipation of heat and low power consumption. In this study a reversible logic gate based design of variable precision multi...

  20. Local anesthesia reversal.

    Science.gov (United States)

    Malamed, Stanley F

    2010-03-01

    PM (OraVerse) enables the dentist or dental hygienist (where permitted) to significantly decrease the duration of residual STA in patients where such numbness may prove to be potentially injurious (children, geriatric, and special needs patients), or a negative influence on their quality of life (speaking, eating, negative body image). (Note: As of August 3, 2009, dental hygienists are permitted to administer PM in the following states: Alaska, Arkansas, Hawaii, Idaho, Iowa, Louisiana, Montana, Nevada, New York, North Dakota, Oklahoma, Rhode Island, Tennessee, Utah, and Wisconsin.)

  1. 4-Vinylcyclohexene diepoxide reduces fertility in female Siberian hamsters when treated during their reproductively active and quiescent states.

    Science.gov (United States)

    Roosa, Kristen A; Mukai, Motoko; Place, Ned J

    2015-01-01

    The industrial compound 4-vinylcyclohexene diepoxide (VCD) destroys ovarian follicles and reduces fertility in rodents, but to date VCD has not been tested in species that experience seasonal anestrus. To determine if VCD destroys follicles when administered during reproductive quiescence, Siberian hamsters were treated with VCD (240mg/kg i.p. daily for 10 days) during short days, and outcomes were compared with reproductively active females that were maintained and treated in long days. Primordial follicle numbers were significantly reduced by VCD under both day lengths, and reproductive quiescence in short days did not appear to render the ovaries less susceptible to VCD-induced follicle depletion. Independent of day length and reproductive state, VCD-treated hamsters weaned substantially fewer offspring than controls. These results suggest that time of year may not be an important consideration for optimizing use of VCD in the field when the target pest species is a seasonally breeding rodent.

  2. Targeting Quiescence in Prostate Cancer

    Science.gov (United States)

    2016-10-01

    can be used to monitor and isolate cancer cells that are quiescent vs. actively proliferating. With these new tools we verified that prostate...Collagen Implants with labeled cancer cells 3wk Optimization in progress Subtask 2: Remove Collagen Implants 1 Subtask 3: Isolate tissues and...Subtask 4: Isolate tissues and perform flow cytometry to identify cell cycle distributions of metastatic populations* (Timepoints throughout 1-7 months

  3. A Typology of Reverse Innovation

    DEFF Research Database (Denmark)

    von Zedtwitz, Max; Corsi, Simone; Søberg, Peder Veng

    2015-01-01

    taking place in an emerging country. This analytical framework allows recasting of current research at the intersection between innovation and international business. Of the 10 reverse innovation flows, six are new and have not been covered in the literature to date. The study addresses questions......Reverse innovation commonly refers to an innovation initially launched in a developing country and later introduced to an advanced country. Adopting a linear innovation model with the four sequential phases of concept ideation, product development, primary target market introduction, and subsequent......, the paper then introduces a typology of global innovation with 16 different types of innovation flows between advanced and emerging countries, 10 of which are reverse innovation flows. The latter are further differentiated into weak and strong reverse innovation, depending on the number of innovation phases...

  4. Designing the Reverse Supply Chain

    DEFF Research Database (Denmark)

    Gobbi, Chiara

    2011-01-01

    for the reverse supply chain. Design/methodology/approach – In order to identify the relevance of the Fisher model, the model needs to be recast in terms of PRV, which, in this context, is considered the independent variable in the reverse logistics arena. Products defined as innovative in Fisher's taxonomy...... is associated with first-class recovery options (reconditioning and remarketing). When the recovery option is recycling, time is not relevant, the primary objective is cost reduction (efficiency), the chain is centralized, and actors and phases of the reverse chain are determined by the specificity...... of the recycling process. When the recovery option is reconditioning, time is primarily relevant, tradeoffs between costs and time efficiency are necessary, the chain presents a centralized structure, and the presence of other types of actors and phases influences the structure of the reverse supply chain...

  5. Towards a reversible functional language

    DEFF Research Database (Denmark)

    Yokoyama, Tetsuo; Axelsen, Holger Bock; Glück, Robert

    2012-01-01

    first-match policy for case expressions, we can write overlapping patterns in case branches, as is customary in ordinary functional languages, and also in leaf expressions, unlike existing inverse interpreter methods, which enables concise programs. In patterns, the use of a duplication......We identify concepts of reversibility for a functional language by means of a set of semantic rules with specific properties. These properties include injectivity along with local backward determinism, an important operational property for an efficient reversible language. We define a concise...... reversible first-order functional language in which access to the backward semantics is provided to the programmer by inverse function calls. Reversibility guarantees that in this language a backward run (inverse interpretation) is as fast as the corresponding forward run itself. By adopting a symmetric...

  6. An Overview of Reverse Logistics

    Institute of Scientific and Technical Information of China (English)

    WANG Jia-xiang; HE Xin

    2005-01-01

    Until recently, investment in logistics has focused mainly on the flows from companies to markets. Growing concerns for the environment and conserving resources have created new logistical approaches to more effectively manage the distribution function, and make better use of the resources available to an organization. One such approach is reverse logistics, which uses various methods to give scope for a back-load of finished products, components, waste, reusable packing, etc. from consumer to manufacturer. Back-loads allow manufacturers to reduce costs by using the distribution vehicle's return journey to create income or added value. This basic concept is now being developed to create novel solutions to the problems of reducing pollution, costs and vehicle movements, whilst maintaining high customer service levels. In this paper, the idea of reverse logistics is presented; motivations for it are analyzed, several successful practices are demonstrated and some important truths regarding successful reverse logistics are identified, trend of reverse logistics is provided.

  7. CONCEPTUAL ISSUES REGARDING REVERSE LOGISTICS

    National Research Council Canada - National Science Library

    Ioana Olariu

    2014-01-01

    ... of reverse logistics in companies. Many firms attracted by the value available in the flow, have proactively participated in handling returned products at the end of their usefulness or from other parts of the product life cycle...

  8. Seismic quiescence precursors to the last two damaging sequences in Central Italy (2009 Mw = 6.3 L'Aquila and 2016 Mw 6.5 Amatrice-Norcia)

    Science.gov (United States)

    Gentili, Stefania; Di Giovambattista, Rita; Peresan, Antonella

    2017-04-01

    The 2016 seismic sequence in central Italy fell in a seismic gap between northern and central Apennines, between the 1997-1998 Umbria-Marche and the 2009 L'Aquila earthquakes, which occurred around 50 km to the northwest and the southeast, respectively. We investigated seismicity patterns preceding the occurrence of the 2009 and 2016 earthquakes. We applied the Region Time Length (RTL) algorithm to study detailed property of the quiescence. The algorithm measures the level of seismic activity in moving time windows by counting the number of earthquakes, weighted by their size, and inversely weighted by their distance, in time and space from the point of observation. We used a declustered catalogue. Declustering is particularly difficult in the Apennines, due to the closeness in space and time of different clusters. For this reason, to detect earthquake clusters, we used a statistical method called "nearest-neighbours" based on nearest-neighbour distances of events in space-time-energy domain. The method allows decomposing the seismic catalogue into background seismicity and individual sequences of earthquake clusters. We found that both the L'Aquila and the Amatrice events were preceded by periods of seismic quiescence in the focal region. The analyzed cases are also compared to the results available in literature applying RTL and Z-mapping to previous Italian events, including the 1997-1998 Umbria-Marche earthquake.

  9. Laparoscopic reversal of Hartmann's procedure

    DEFF Research Database (Denmark)

    Svenningsen, Peter Olsen; Bulut, Orhan; Jess, Per

    2010-01-01

    A change in procedure from open to laparoscopic reversal of Hartmann's colostomy was implemented at our department between May 2005 and December 2008. The aim of the study was to investigate if this change was beneficial for the patients.......A change in procedure from open to laparoscopic reversal of Hartmann's colostomy was implemented at our department between May 2005 and December 2008. The aim of the study was to investigate if this change was beneficial for the patients....

  10. Reversible transdifferentiation of alveolar epithelial cells.

    Science.gov (United States)

    Danto, S I; Shannon, J M; Borok, Z; Zabski, S M; Crandall, E D

    1995-05-01

    Alveolar epithelial type II (AT2) cells have been thought to be the progenitors of terminally differentiated type I (AT1) cells in the adult animal in vivo. In this study, we used an AT1 cell-specific monoclonal antibody (mAb VIII B2) to investigate expression of the AT1 cell phenotype accompanying reversible changes in expression of the AT2 cell phenotype. AT2 cells were isolated and cultured either on attached collagen gels or on gels detached 1 or 4 days after plating and maintained thereafter as floating gels. Monolayers on both attached and floating gels were harvested on days 4 and 8 and analyzed by electron microscopy for changes in morphology and binding of mAb VIII B2. Results indicate that: (1) alveolar epithelial cells (AEC) on attached gels develop characteristics of the AT1 cell phenotype, (2) AEC on gels detached on day 1 maintain features of the AT2 cell phenotype (and do not react with mAb VIII B2), and (3) the expression of AT1 cell phenotypic traits seen by day 4 on attached gels is reversed after detachment. We conclude that commitment to the AT1 and AT2 cell lineages requires continuous regulatory input to maintain the differentiated states, and that transdifferentiation between AT2 and AT1 cells may be reversible.

  11. Reverse triiodothyronine in protein energy malnutrition

    Energy Technology Data Exchange (ETDEWEB)

    Hafiez, A.A.; Abdel-Salam, E.; Abbas, E.Z.; Halawa, F.A.; El-Hefnawy, N. (Cairo Univ. (Egypt))

    1984-08-01

    Serum levels of thyroxine (T/sub 4/), triiodothyronine (T/sub 3/), reverse triiodothyronine (rT/sub 3/) and thyrotropin (TSH) were determined in cases of kwashiorkor and marasmus. Decreased levels of T/sub 4/ and T/sub 3/, and increased levels of rT/sub 3/ with no change in TSH were obtained. Thus in infants suffering from protein energy malnutrition there is a state of thyroid dysfunction as well as a shift in the peripheral T/sub 4/ metabolism being converted to the inert rT/sub 3/ rather than to the physiologically active T/sub 3/.

  12. Reversible part of a quantum dynamical system

    OpenAIRE

    2016-01-01

    In this work a quantum dynamical system $(\\mathfrak M,\\Phi, \\varphi)$ is constituted by a von Neumann algebra $\\mathfrak M$, by a unital Schwartz map $\\Phi:\\mathfrak{M\\rightarrow M}$ and by a $\\Phi$-invariant normal faithful state $\\varphi$ on $\\mathfrak M$. The ergodic properties of a quantum dynamical system, depends on its reversible part $(\\mathfrak{D}_\\infty,\\Phi_\\infty, \\varphi_\\infty)$. It is constituted by a von Neumann sub-algebra $\\mathfrak{D}_\\infty$ of $\\mathfrak M$ by an automorp...

  13. Reverse mathematics and properties of finite character

    CERN Document Server

    Dzhafarov, Damir D

    2011-01-01

    We study the reverse mathematics of the principle stating that, for every property of finite character, every set of natural numbers has a maximal subset satisfying the property. In the context of set theory, this variant of Tukey's lemma is equivalent to the axiom of choice. We study its behavior in the context of second-order arithmetic, and give a full characterization of the strength of the principle in terms of the quantifier structure of the formula defining the property. We then study the interaction between properties of finite character and finitary closure operators, and the interaction between these properties and a class of nondeterministic closure operators which we introduce.

  14. Implications of Scheduled ITC Reversion for RPS Compliance: Preliminary Results

    Energy Technology Data Exchange (ETDEWEB)

    Lowder, Travis; Miller, John; O' Shaughnessy, Eric; Heeter, Jenny

    2015-09-14

    This poster presents DRAFT initial results of a forthcoming NREL analysis. The analysis investigates the impacts of the scheduled investment tax credit (ITC) reversion from 30 percent to 10 percent for certain solar photovoltaic projects. Specifically, it considers whether the reversion will result in increased use of alternative compliance payments (ACPs) in lieu of solar renewable energy credits (SRECs) for renewable portfolio standard (RPS) compliance. The analysis models the effect of a 10 percent ITC on power purchase agreement (PPA) prices for non-residential systems in the eight states with solar carve-outs and solar ACPs. Our preliminary results suggest that states will likely install sufficient capacity to meet long-term targets through SRECs rather than ACPs following the ITC reversion. However, the analysis shows that the ITC reversion could affect project economics such that capacity shortfalls in certain states could temporarily increase the use of ACPs. NREL anticipates publishing a full report of this analysis in fall 2015. credits (SRECs) for renewable portfolio standard (RPS) compliance. The analysis models the effect of a 10 percent ITC on power purchase agreement (PPA) prices for non-residential systems in the eight states with solar carve-outs and solar ACPs. Our preliminary results suggest that states will likely install sufficient capacity to meet long-term targets through SRECs rather than ACPs following the ITC reversion. However, the analysis shows that the ITC reversion could affect project economics such that capacity shortfalls in certain states could temporarily increase the use of ACPs. NREL anticipates publishing a full report of this analysis in fall 2015.

  15. Implications of Scheduled ITC Reversion for RPS Compliance: Preliminary Results

    Energy Technology Data Exchange (ETDEWEB)

    Lowder, Travis; Miller, John; O' Shaughnessy, Eric; Heeter, Jenny

    2015-09-14

    This poster presents DRAFT initial results of a forthcoming NREL analysis. The analysis investigates the impacts of the scheduled investment tax credit (ITC) reversion from 30 percent to 10 percent for certain solar photovoltaic projects. Specifically, it considers whether the reversion will result in increased use of alternative compliance payments (ACPs) in lieu of solar renewable energy credits (SRECs) for renewable portfolio standard (RPS) compliance. The analysis models the effect of a 10 percent ITC on power purchase agreement (PPA) prices for non-residential systems in the eight states with solar carve-outs and solar ACPs. Our preliminary results suggest that states will likely install sufficient capacity to meet long-term targets through SRECs rather than ACPs following the ITC reversion. However, the analysis shows that the ITC reversion could affect project economics such that capacity shortfalls in certain states could temporarily increase the use of ACPs. NREL anticipates publishing a full report of this analysis in fall 2015. credits (SRECs) for renewable portfolio standard (RPS) compliance. The analysis models the effect of a 10 percent ITC on power purchase agreement (PPA) prices for non-residential systems in the eight states with solar carve-outs and solar ACPs. Our preliminary results suggest that states will likely install sufficient capacity to meet long-term targets through SRECs rather than ACPs following the ITC reversion. However, the analysis shows that the ITC reversion could affect project economics such that capacity shortfalls in certain states could temporarily increase the use of ACPs. NREL anticipates publishing a full report of this analysis in fall 2015.

  16. Dual Biochemical Oscillators May Control Cellular Reversals in Myxococcus xanthus

    Science.gov (United States)

    Eckhert, Erik; Rangamani, Padmini; Davis, Annie E.; Oster, George; Berleman, James E.

    2014-01-01

    Myxococcus xanthus is a Gram-negative, soil-dwelling bacterium that glides on surfaces, reversing direction approximately once every 6 min. Motility in M. xanthus is governed by the Che-like Frz pathway and the Ras-like Mgl pathway, which together cause the cell to oscillate back and forth. Previously, Igoshin et al. (2004) suggested that the cellular oscillations are caused by cyclic changes in concentration of active Frz proteins that govern motility. In this study, we present a computational model that integrates both the Frz and Mgl pathways, and whose downstream components can be read as motor activity governing cellular reversals. This model faithfully reproduces wildtype and mutant behaviors by simulating individual protein knockouts. In addition, the model can be used to examine the impact of contact stimuli on cellular reversals. The basic model construction relies on the presence of two nested feedback circuits, which prompted us to reexamine the behavior of M. xanthus cells. We performed experiments to test the model, and this cell analysis challenges previous assumptions of 30 to 60 min reversal periods in frzCD, frzF, frzE, and frzZ mutants. We demonstrate that this average reversal period is an artifact of the method employed to record reversal data, and that in the absence of signal from the Frz pathway, Mgl components can occasionally reverse the cell near wildtype periodicity, but frz- cells are otherwise in a long nonoscillating state. PMID:25468349

  17. Reversibility and energy dissipation in adiabatic superconductor logic.

    Science.gov (United States)

    Takeuchi, Naoki; Yamanashi, Yuki; Yoshikawa, Nobuyuki

    2017-03-06

    Reversible computing is considered to be a key technology to achieve an extremely high energy efficiency in future computers. In this study, we investigated the relationship between reversibility and energy dissipation in adiabatic superconductor logic. We analyzed the evolution of phase differences of Josephson junctions in the reversible quantum-flux-parametron (RQFP) gate and confirmed that the phase differences can change time reversibly, which indicates that the RQFP gate is physically, as well as logically, reversible. We calculated energy dissipation required for the RQFP gate to perform a logic operation and numerically demonstrated that the energy dissipation can fall below the thermal limit, or the Landauer bound, by lowering operation frequencies. We also investigated the 1-bit-erasure gate as a logically irreversible gate and the quasi-RQFP gate as a physically irreversible gate. We calculated the energy dissipation of these irreversible gates and showed that the energy dissipation of these gate is dominated by non-adiabatic state changes, which are induced by unwanted interactions between gates due to logical or physical irreversibility. Our results show that, in reversible computing using adiabatic superconductor logic, logical and physical reversibility are required to achieve energy dissipation smaller than the Landauer bound without non-adiabatic processes caused by gate interactions.

  18. A spin reversal system for polarized epithermal neutrons

    Energy Technology Data Exchange (ETDEWEB)

    Bowman, J.D. [Los Alamos Nat. Lab., NM (United States); Penttilae, S.I. [Los Alamos Nat. Lab., NM (United States); Tippens, W.B. [University of Virginia, Charlottesville, VA 22903 (United States)

    1996-01-21

    The design and construction of a spin-reversal system for longitudinally polarized epithermal neutrons are presented. The design uses a static magnetic field parallel to the momentum of the neutron. The longitudinal field changes the direction at its midpoint. A transverse magnetic field is turned off to control the spin direction at the end of the spin flipper. The neutron spin is reversed with respect to both the neutron momentum and the static longitudinal field at the exit of the spin flipper. In the transverse field-on state the spin adiabatically follows the field direction and the spin direction is reversed. In the transverse field-off state the spin passes rapidly through the region where the solenoidal field reverses the sign and the spin direction is not reversed. With this design, the spins of an 8-cm-diameter beam of longitudinally polarized neutrons can be reversed with an efficiency greater than 88% over a range of neutron energies of more than four orders of magnitude. (orig.).

  19. A spin reversal system for polarized epithermal neutrons

    Science.gov (United States)

    Bowman, J. D.; Penttilä, S. I.; Tippens, W. B.

    1996-02-01

    The design and construction of a spin-reversal system for longitudinally polarized epithermal neutrons are presented. The design uses a static magnetic field parallel to the momentum of the neutron. The longitudinal field changes the direction at its midpoint. A transverse magnetic field is turned off to control the spin direction at the end of the spin flipper. The neutron spin is reversed with respect to both the neutron momentum and the static longitudinal field at the exit of the spin flipper. In the transverse field-on state the spin adiabatically follows the field direction and the spin direction is reversed. In the transverse field-off state the spin passes rapidly through the region where the solenoidal field reverses the sign and the spin direction is not reversed. With this design, the spins of an 8-cm-diameter beam of longitudinally polarized neutrons can be reversed with an efficiency greater than 88% over a range of neutron energies of more than four orders of magnitude.

  20. Angular-dependent magnetization reversal processes in artificial spin ice

    Science.gov (United States)

    Burn, D. M.; Chadha, M.; Branford, W. R.

    2015-12-01

    The angular dependence of the magnetization reversal in interconnected kagome artificial spin ice structures has been studied through experimental MOKE measurements and micromagnetic simulations. This reversal is mediated by the propagation of magnetic domain walls along the interconnecting bars, which either nucleate at the vertex or arrive following an interaction in a neighboring vertex. The physical differences in these processes show a distinct angular dependence allowing the different contributions to be identified. The configuration of the initial magnetization state, either locally or on a full sublattice of the system, controls the reversal characteristics of the array within a certain field window. This shows how the available magnetization reversal routes can be manipulated and the system can be trained.

  1. REVERSE LOGISTICS RETAIL LEVEL RETURN

    Directory of Open Access Journals (Sweden)

    Ivona Bajor

    2014-06-01

    Full Text Available Conducting scientific research regarding reverse logistics systems includes certain difficulties. Developed logistics systems are aimed at analysing reverse logistics issues and tend to continuously detect differences and oscillations in the flow of returned products and their characteristics. Developing logistics systems, as Croatian, find reverse logistics issues, regarding product returns, significantly complex and very often these issues are not observed as issues of priority. As distributive flow, reverse logistics systems fundaments should be also based on detailed analysis. Analysis in this flow presents amounts, reasons, process flows and quality of returned items. Because of complex product evaluation on individual level, reverse logistics procedures should be implemented as a methodology individually developed for every supply chain subject. This paper presents a research of retail level returns on the Croatian market, where the analysis implicated that the majority of products in return for this level is directed from final consumers and presents noncurrent inventories of distribution chain. The paper will present conducted research regarding characteristics of returns and routing these products from the retail level.

  2. Cylindrical air flow reversal barrier

    Energy Technology Data Exchange (ETDEWEB)

    Woznica, C.; Rodziewicz, M.

    1988-06-01

    Describes an innovative design introduced in the ZMP mine in Zory for quick reversal of ventilation air flow. Geologic mining conditions at the 705 m deep horizon, where the barrier was built, are described. According to the design used until now, a reversal system consisted of safety barriers, ventilation air locks, a ventilation bridge and stopping needed in case of a fire when air flow direction must be reversed. Nine air locks and an expensive concrete ventilation bridge were needed and the air locks had to be operated at 8 points of the region to effect reversal. The new design consists of a 2-storey cylindrical barrier which also fulfills the function of a ventilation bridge. It can be manually or remotely operated by a mechanical or pneumatic system. Tests showed that the new barrier permits immediate air flow reversal while retaining 60% of the original air, which is important in the case of fire and methane hazards. It permits improved seam panelling and splitting of pillars and brings an economy of about 40 million zlotys in construction cost. Design and operation of the barrier is illustrated and ventilation air circulation is explained. 7 figs.

  3. Low Cost Reversible Signed Comparator

    Directory of Open Access Journals (Sweden)

    Farah Sharmin

    2013-10-01

    Full Text Available Nowadays exponential advancement in reversible comp utation has lead to better fabrication and integration process. It has become very popular ove r the last few years since reversible logic circuit s dramatically reduce energy loss. It consumes less p ower by recovering bit loss from its unique input-o utput mapping. This paper presents two new gates called RC-I and RC-II to design an n-bit signed binary comparator where simulation results show that the p roposed circuit works correctly and gives significa ntly better performance than the existing counterparts. An algorithm has been presented in this paper for constructing an optimized reversible n-bit signed c omparator circuit. Moreover some lower bounds have been proposed on the quantum cost, the numbers of g ates used and the number of garbage outputs generated for designing a low cost reversible sign ed comparator. The comparative study shows that the proposed design exhibits superior performance consi dering all the efficiency parameters of reversible logic design which includes number of gates used, quantum cost, garbage output and constant inputs. This proposed design has certainly outperformed all the other existing approaches.

  4. Vasectomy reversal: a clinical update

    Directory of Open Access Journals (Sweden)

    Abhishek P Patel

    2016-01-01

    Full Text Available Vasectomy is a safe and effective method of contraception used by 42-60 million men worldwide. Approximately 3%-6% of men opt for a vasectomy reversal due to the death of a child or divorce and remarriage, change in financial situation, desire for more children within the same marriage, or to alleviate the dreaded postvasectomy pain syndrome. Unlike vasectomy, vasectomy reversal is a much more technically challenging procedure that is performed only by a minority of urologists and places a larger financial strain on the patient since it is usually not covered by insurance. Interest in this procedure has increased since the operating microscope became available in the 1970s, which consequently led to improved patency and pregnancy rates following the procedure. In this clinical update, we discuss patient evaluation, variables that may influence reversal success rates, factors to consider in choosing to perform vasovasostomy versus vasoepididymostomy, and the usefulness of vasectomy reversal to alleviate postvasectomy pain syndrome. We also review the use of robotics for vasectomy reversal and other novel techniques and instrumentation that have emerged in recent years to aid in the success of this surgery.

  5. Reversible phenotypic plasticity with continuous adaptation.

    Science.gov (United States)

    Pfab, Ferdinand; Gabriel, Wilfried; Utz, Margarete

    2016-01-01

    We introduce a novel model for continuous reversible phenotypic plasticity. The model includes a one-dimensional environmental gradient, and we describe performance of an organism as a function of the environmental state by a Gaussian tolerance curve. Organisms are assumed to adapt their tolerance curve after a change of the environmental state. We present a general framework for calculating the genotype fitness if such adaptations happen in a continuous manner and apply the model to a periodically changing environment. Significant differences of our model with previous models for plasticity are the continuity of adaptation, the presence of intermediate phenotypes, that the duration of transformations depends on their extent, fewer restrictions on the distribution of the environment, and a higher robustness with respect to assumptions about environmental fluctuations. Further, we show that continuous reversible plasticity is beneficial mainly when environmental changes occur slow enough so that fully developed phenotypes can be exhibited. Finally we discuss how the model framework can be generalized to a wide variety of biological scenarios from areas that include population dynamics, evolution of environmental tolerance and physiology.

  6. Laparoscopic reversal of Hartmann's procedure

    DEFF Research Database (Denmark)

    Svenningsen, Peter Olsen; Bulut, Orhan; Jess, Per

    2010-01-01

    INTRODUCTION: A change in procedure from open to laparoscopic reversal of Hartmann's colostomy was implemented at our department between May 2005 and December 2008. The aim of the study was to investigate if this change was beneficial for the patients. MATERIAL AND METHODS: The medical records...... of all patients who underwent reversal of a colostomy after a primary Hartmann's procedure during the period May 2005 to December 2008 were reviewed retrospectively in a case-control study. RESULTS: A total of 43 patients were included. Twenty-one had a laparoscopic and 22 an open procedure. The two...

  7. Reversible Switching of Cooperating Replicators

    Science.gov (United States)

    Urtel, Georg C.; Rind, Thomas; Braun, Dieter

    2017-02-01

    How can molecules with short lifetimes preserve their information over millions of years? For evolution to occur, information-carrying molecules have to replicate before they degrade. Our experiments reveal a robust, reversible cooperation mechanism in oligonucleotide replication. Two inherently slow replicating hairpin molecules can transfer their information to fast crossbreed replicators that outgrow the hairpins. The reverse is also possible. When one replication initiation site is missing, single hairpins reemerge from the crossbreed. With this mechanism, interacting replicators can switch between the hairpin and crossbreed mode, revealing a flexible adaptation to different boundary conditions.

  8. Marburg Virus Reverse Genetics Systems.

    Science.gov (United States)

    Schmidt, Kristina Maria; Mühlberger, Elke

    2016-06-22

    The highly pathogenic Marburg virus (MARV) is a member of the Filoviridae family and belongs to the group of nonsegmented negative-strand RNA viruses. Reverse genetics systems established for MARV have been used to study various aspects of the viral replication cycle, analyze host responses, image viral infection, and screen for antivirals. This article provides an overview of the currently established MARV reverse genetic systems based on minigenomes, infectious virus-like particles and full-length clones, and the research that has been conducted using these systems.

  9. Marburg Virus Reverse Genetics Systems

    Directory of Open Access Journals (Sweden)

    Kristina Maria Schmidt

    2016-06-01

    Full Text Available The highly pathogenic Marburg virus (MARV is a member of the Filoviridae family and belongs to the group of nonsegmented negative-strand RNA viruses. Reverse genetics systems established for MARV have been used to study various aspects of the viral replication cycle, analyze host responses, image viral infection, and screen for antivirals. This article provides an overview of the currently established MARV reverse genetic systems based on minigenomes, infectious virus-like particles and full-length clones, and the research that has been conducted using these systems.

  10. A Case for Dynamic Reverse-code Generation to Debug Non-deterministic Programs

    Directory of Open Access Journals (Sweden)

    Jooyong Yi

    2013-09-01

    Full Text Available Backtracking (i.e., reverse execution helps the user of a debugger to naturally think backwards along the execution path of a program, and thinking backwards makes it easy to locate the origin of a bug. So far backtracking has been implemented mostly by state saving or by checkpointing. These implementations, however, inherently do not scale. Meanwhile, a more recent backtracking method based on reverse-code generation seems promising because executing reverse code can restore the previous states of a program without state saving. In the literature, there can be found two methods that generate reverse code: (a static reverse-code generation that pre-generates reverse code through static analysis before starting a debugging session, and (b dynamic reverse-code generation that generates reverse code by applying dynamic analysis on the fly during a debugging session. In particular, we espoused the latter one in our previous work to accommodate non-determinism of a program caused by e.g., multi-threading. To demonstrate the usefulness of our dynamic reverse-code generation, this article presents a case study of various backtracking methods including ours. We compare the memory usage of various backtracking methods in a simple but nontrivial example, a bounded-buffer program. In the case of non-deterministic programs such as this bounded-buffer program, our dynamic reverse-code generation outperforms the existing backtracking methods in terms of memory efficiency.

  11. Nickel-hydrogen cell reversal characteristics

    Science.gov (United States)

    Lurie, Charles

    1994-01-01

    Nickel-hydrogen cell reversal characteristics are being studied as part of a TRW program directed towards development of a high current battery cell bypass switch. The following are discussed: cell bypass switch; nickel-hydrogen cell reversal characteristics; and nickel-hydrogen cell chemistry: discharge/reversal and overdischarge (reversal) with nickel and hydrogen precharge.

  12. Vasectomy reversal : a clinical update

    NARCIS (Netherlands)

    A.P. Patel (Abhishek); R.P. Smith (Ryan)

    2016-01-01

    textabstractVasectomy is a safe and effective method of contraception used by 42-60 million men worldwide. Approximately 3%-6% of men opt for a vasectomy reversal due to the death of a child or divorce and remarriage, change in financial situation, desire for more children within the same marriage,

  13. CAPSULE REPORT: REVERSE OSMOSIS PROCESS

    Science.gov (United States)

    A failure analysis has been completed for the reverse osmosis (RO) process. The focus was on process failures that result in releases of liquids and vapors to the environment. The report includes the following: 1) A description of RO and coverage of the principles behind the proc...

  14. CAPSULE REPORT: REVERSE OSMOSIS PROCESS

    Science.gov (United States)

    A failure analysis has been completed for the reverse osmosis (RO) process. The focus was on process failures that result in releases of liquids and vapors to the environment. The report includes the following: 1) A description of RO and coverage of the principles behind the proc...

  15. A Framework for Reverse Logistics

    NARCIS (Netherlands)

    M.P. de Brito (Marisa); R. Dekker (Rommert)

    2003-01-01

    textabstractReverse Logistics has been stretching out worldwide, involving all the layers of supply chains in various industry sectors. While some actors in the chain have been forced to take products back, others have pro-actively done so, attracted by the value in used products One way or the othe

  16. Time-reversible Hamiltonian systems

    NARCIS (Netherlands)

    Schaft, Arjan van der

    1982-01-01

    It is shown that transfer matrices satisfying G(-s) = G(s) = G^T(-s) have a minimal Hamiltonian realization with an energy which is the sum of potential and kinetic energy, yielding the time reversibility of the equations. Furthermore connections are made with an associated gradient system. The

  17. Reversible colour change in Arthropoda.

    Science.gov (United States)

    Umbers, Kate D L; Fabricant, Scott A; Gawryszewski, Felipe M; Seago, Ainsley E; Herberstein, Marie E

    2014-11-01

    The mechanisms and functions of reversible colour change in arthropods are highly diverse despite, or perhaps due to, the presence of an exoskeleton. Physiological colour changes, which have been recorded in 90 arthropod species, are rapid and are the result of changes in the positioning of microstructures or pigments, or in the refractive index of layers in the integument. By contrast, morphological colour changes, documented in 31 species, involve the anabolism or catabolism of components (e.g. pigments) directly related to the observable colour. In this review we highlight the diversity of mechanisms by which reversible colour change occurs and the evolutionary context and diversity of arthropod taxa in which it has been observed. Further, we discuss the functions of reversible colour change so far proposed, review the limited behavioural and ecological data, and argue that the field requires phylogenetically controlled approaches to understanding the evolution of reversible colour change. Finally, we encourage biologists to explore new model systems for colour change and to engage scientists from other disciplines; continued cross-disciplinary collaboration is the most promising approach to this nexus of biology, physics, and chemistry.

  18. Reverse Knowledge Transfer in MNEs

    DEFF Research Database (Denmark)

    Mudambi, Ram; Piscitello, Lucia; Rabbiosi, Larissa

    2014-01-01

    , and that the curvilinearity is greater for greenfield entries relative to acquisition entries. The U-shaped relationship between subsidiary innovativeness and reverse knowledge transfers, as well as the sensitivity of this result to entry mode are important new findings in the literature on the role of subsidiaries...

  19. CT小肠造影对克罗恩病活动期与静止期的诊断价值%The Diagnostic Value of CT Enterography in Activity and Quiescence for Crohn's disease

    Institute of Scientific and Technical Information of China (English)

    朱庆强; 王中秋; 陈文新; 朱文荣; 吴晶涛; 王守安

    2012-01-01

    Objective To discuss the diagnostic value of CT enterography in activity and quiescence for Crohn's dis-ease. Materials and Methods 39 cases of Crohn's disease confirmed by surgery and pathology were retrospectively ana-lyzed. Imaging findings of Activity and quiescence were observed. Results 39 patients with Crohn's disease, 28 cases were in activity, 11 patients in quiescence; Active imaging findings included intestinal wall layers, severe enhancement, ulcers, comb sign, swollen lymph nodes, intestinal fistula, phlegmon, and the number of occurred were 23/28 (81.4% ), 21/28 (75% ), 13/28 (46.4% ), 9 / 28 (32.1% ) 13/28 (46.4% ), 13/28 (46.4% ), 12 / 28 (42.8% ) respective-ly. Quiescent imaging findings included mural wall fibrosis, nonenhancement to mild enhancement, mural fat, inflammato-ry polyps, abscess, inflammatory mass, and the number of occurred were 7/11 (63. 6% ), 8 / 11 (72. 7% ) ,4 / 11 (36.4% ), 10/11 ( 90.9% ) , 10/11 (90.9% ), 7 / 11 (63.6% ) respectively. Conclusion The CT enteroclysis can usefully and objectively reflect the activity and quiescence of Crohn' s disease, which is helpful in guiding the clinical treat-ment.%目的 探讨CT小肠造影对克罗恩病(CD)活动期与静止期的诊断价值,以期对临床治疗有所帮助.资料与方法 回顾性分析经病理、手术证实的39例CD患者的CT小肠造影表现,重点观察病变活动期及静止期情况.结果 39例CD,病变活动期28例,慢性期11例,活动期指标:肠壁分层、重度强化、木梳征、淋巴结肿大、肠瘘、蜂窝织炎,发生例数分别为:23/28(81.4%)、21/28(75%)、9/28(32.1%)、13/28(46.4%)、13/28(46.4%)、12/28 (42.8%);慢性期指标:肠壁单层增厚、不强化~轻度强化、肠壁内脂肪、脓肿、炎性肿块,发生例数分别为:7/11(63.6%)、8/11(72.7%)、4/11 (36.4%)、10/11 (90.9%)、7/11(63.6%).结论 CT小肠造影可全面评价CD的活动性与静止性表现,对于指导CD的临床治疗具有重要价值.

  20. Reversal in China’s Mineral Risk Prospecting Investment Pattern

    Institute of Scientific and Technical Information of China (English)

    2013-01-01

    <正>The total size of China’s central and provincial level geological prospecting funds has reached 39.9 billion yuan,which effectively propelled social capital to make investment in mineral resources risk prospecting through cooperation,and reversed the previous pattern that China’s mining risk prospecting totally relied on investment by the state government.

  1. Elements of a reversible object-oriented language

    DEFF Research Database (Denmark)

    Schultz, Ulrik Pagh; Axelsen, Holger Bock

    2016-01-01

    This paper presents initial ideas for the design and implementation of a reversible object-oriented language based on extending Janus with object-oriented concepts such as classes that encapsulate behavior and state, inheritance, virtual dispatching, as well as constructors. We show that virtual ...

  2. Fluorescence dynamics of green fluorescent protein in AOT reversed micelles

    NARCIS (Netherlands)

    Uskova, M.A.; Borst, J.W.; Hink, M.A.; Hoek, van A.; Schots, A.; Klyachko, N.L.; Visser, A.J.W.G.

    2000-01-01

    We have used the enhanced green fluorescent protein (EGFP) to investigate the properties of surfactant-entrapped water pools in organic solvents (reversed micelles) with steady-state and time-resolved fluorescence methods. The surfactant used was sodium bis(2-ethylhexyl)sulfosuccinate (AOT) and the

  3. Some new approaches to the study of the Earth's magnetic field reversals

    Directory of Open Access Journals (Sweden)

    G. Consolini

    2003-06-01

    Full Text Available Paleomagnetic studies clearly show that the polarity of the magnetic fi eld has been subject to reversals. It is generally assumed that polarity intervals are exponentially distributed. Here, the geomagnetic polarity reversal record, for the past 166 Ma, is analysed and a new approach to the study of the reversals is presented. In detail, the occurrence of 1/f-noise in the Power Spectral Density (PSD, relative to geomagnetic fi eld reversals, the existence of a Zipf's law behaviour for the cumulative distribution of polarity intervals, and the occurrence of punctuated equilibrium, as shown by a sort of Devil's staircase for the reversal time series, are investigated. Our results give a preliminary picture of the dynamical state of the geomagnetic dynamo suggesting that the geodynamo works in a marginally stable out-of-equilibrium confi guration, and that polarity reversals are equivalent to a sort of phase transition between two metastable states.

  4. Reversible and Reproducible Giant Universal Electroresistance Effect

    Institute of Scientific and Technical Information of China (English)

    SYED Rizwan; ZHANG Sen; YU Tian; ZHAO Yong-Gang; ZHANG Shu-Feng; HAN Xiu-Feng

    2011-01-01

    After the prediction of the giant electroresistance effect, much work has been carried out to find this effect in practical devices. We demonstrate a novel way to obtain a large electroresistance (ER) effect in the multilayer system at room temperature. The current-in-plane (CIP) electric transport measurement is performed on the multilayer structure consisting of (011)-Pb(Mg1/3Nb2/3)O3-PbTiO3(PMN-PT)/Ta/Al-O/metal. It is found that the resistance of the top metallic layer shows a hysteretic behavior as a function electric field, which corresponds well with the substrate polarization versus electric Reid (P-E) loop. This reversible hysteretic R-E behavior is independent of the applied magnetic field as well as the magnetic structure of the top metallic layer and keeps its memory state. This novel memory effect is attributed to the polarization reversal induced electrostatic potential, which is felt throughout the multilayer stack and is enhanced by the dielectric Al-O layer producing unique hysteretic, reversible, and reproducible resistance switching behavior. This novel universal electroresistance effect will open a new gateway to the development of future multiferroic memory devices operating at room temperature.%After the prediction of the giant electroresistance effect,much work has been carried out to find this effect in practical devices.We demonstrate a novel way to obtain a large electroresistance (ER) effect in the multilayer system at room temperature.The current-in-plane (CIP) electric transport measurement is performed on the multilayer structure consisting of (011)-Pb(Mg1/3 Nb2/3) O3-PbTiO3 (PMN-PT)/Ta/Al-O/metal.It is found that the resistance of the top metallic layer shows a hysteretic behavior as a function electric field,which corresponds well with the substrate polarization versus electric field (P-E) loop.This reversible hysteretic R-E behavior is independent of the applied magnetic field as well as the magnetic structure of the top metallic

  5. Detection of precursory slips on a fault by the quiescence and activation of seismicity relative to the ETAS model and by the anomalous trend of the geodetic time series of distances between GPS stations around the fault

    Science.gov (United States)

    Ogata, Y.

    2006-12-01

    This paper is concerned with the detection of precursory slip on a rupturing fault, supported by both seismic and geodetic records. Basically, the detection relies on the principle that, assuming precursory slip on the rupturing fault, the seismic activity around the fault should be enhanced or reduced in the zones where increment of the Coulomb failure stress (CFS) is positive or negative, respectively. However, any occurring event also affects the stress changes in neighboring regions, which can trigger further aftershock clusters. Whereas such stress transfers are too difficult to be computed precisely, due to the unknown complex fault system, the ordinary short-term occurrence rate of earthquakes in a region is easily predicted using the ETAS model of triggering seismicity; and any anomalous seismic activity, such as quiescence and activation, can be quantified by identifying a significant deviation from the predicted rate. Such anomalies are revealed to have occurred during several years leading up to the 2004 Chuetsu Earthquake of M6.8, central Honshu, and also the 2005 Western Fukuoka-Ken-Oki Earthquake of M7.0, Kyushu, Japan. Quiescence and activation in the regions coincided with negative and positive increments of the CFS, respectively, and were probably transferred from possible aseismic slips on the focal fault plane. Such slips are further supported by transient crustal movement around the source preceding the rupture. Time series records of the baseline distances between the permanent GPS stations deviated from the predicted trends, with the deviations consistent with the coseismic horizontal displacements of the stations due to these earthquakes. References Ogata, Y. (2006) Report of the Coordinating Committee for Earthquake Prediction, 76 (to appear, in Japanese).

  6. Time reversal invariance in polarized neutron decay

    Energy Technology Data Exchange (ETDEWEB)

    Wasserman, E.G.

    1994-03-01

    An experiment to measure the time reversal invariance violating (T-violating) triple correlation (D) in the decay of free polarized neutrons has been developed. The detector design incorporates a detector geometry that provides a significant improvement in the sensitivity over that used in the most sensitive of previous experiments. A prototype detector was tested in measurements with a cold neutron beam. Data resulting from the tests are presented. A detailed calculation of systematic effects has been performed and new diagnostic techniques that allow these effects to be measured have been developed. As the result of this work, a new experiment is under way that will improve the sensitivity to D to 3 {times} 10{sup {minus}4} or better. With higher neutron flux a statistical sensitivity of the order 3 {times} 10{sup {minus}5} is ultimately expected. The decay of free polarized neutrons (n {yields} p + e + {bar v}{sub e}) is used to search for T-violation by measuring the triple correlation of the neutron spin polarization, and the electron and proton momenta ({sigma}{sub n} {center_dot} p{sub p} {times} p{sub e}). This correlation changes sign under reversal of the motion. Since final state effects in neutron decay are small, a nonzero coefficient, D, of this correlation indicates the violation of time reversal invariance. D is measured by comparing the numbers of coincidences in electron and proton detectors arranged symmetrically about a longitudinally polarized neutron beam. Particular care must be taken to eliminate residual asymmetries in the detectors or beam as these can lead to significant false effects. The Standard Model predicts negligible T-violating effects in neutron decay. Extensions to the Standard Model include new interactions some of which include CP-violating components. Some of these make first order contributions to D.

  7. Integral physicochemical properties of reverse micelles of sodium bis(2-ethylhexyl) sulfosuccinate (AOT)

    Science.gov (United States)

    Fedyaeva, O. A.; Shubenkova, E. G.; Poshelyuzhnaya, E. G.; Lutaeva, I. A.

    2016-08-01

    The effect the degree of hydration has on optical and electrophysical properties of water/AOT/ n-hexane system is studied. It is found that AOT reverse micelles form aggregates whose dimensions grow along with the degree of hydration and temperature. Aggregation enhances their electrical conductivity and shifts the UV spectrum of AOT reverse emulsions to the red region. Four states of water are found in the structure of AOT reverse micelles.

  8. Nondestructive characterization of RBSOA of high-power bipolar transistors. [Reverse-bias safe operating area

    Science.gov (United States)

    Jovanovic, M. M.; Lee, F. C.; Chen, D. Y.

    1986-01-01

    Reverse-bias safe operating area (RBSOA) of high-power Darlington transistors is characterized using a 120 A/1000 V nondestructive reverse-bias second breakdown tester designed and fabricated at Virginia Polytechnic Institute and State University. Elaborate RBSOA characteristics are generated with different forward/reverse base drives and collector current levels. The effects of elevated case temperature and second-base drive on RBSOA of four-terminal Darlington devices are also discussed.

  9. Magnetic stripes and skyrmions with helicity reversals.

    Science.gov (United States)

    Yu, Xiuzhen; Mostovoy, Maxim; Tokunaga, Yusuke; Zhang, Weizhu; Kimoto, Koji; Matsui, Yoshio; Kaneko, Yoshio; Nagaosa, Naoto; Tokura, Yoshinori

    2012-06-05

    It was recently realized that topological spin textures do not merely have mathematical beauty but can also give rise to unique functionalities of magnetic materials. An example is the skyrmion--a nano-sized bundle of noncoplanar spins--that by virtue of its nontrivial topology acts as a flux of magnetic field on spin-polarized electrons. Lorentz transmission electron microscopy recently emerged as a powerful tool for direct visualization of skyrmions in noncentrosymmetric helimagnets. Topologically, skyrmions are equivalent to magnetic bubbles (cylindrical domains) in ferromagnetic thin films, which were extensively explored in the 1970s for data storage applications. In this study we use Lorentz microscopy to image magnetic domain patterns in the prototypical magnetic oxide-M-type hexaferrite with a hint of scandium. Surprisingly, we find that the magnetic bubbles and stripes in the hexaferrite have a much more complex structure than the skyrmions and spirals in helimagnets, which we associate with the new degree of freedom--helicity (or vector spin chirality) describing the direction of spin rotation across the domain walls. We observe numerous random reversals of helicity in the stripe domain state. Random helicity of cylindrical domain walls coexists with the positional order of magnetic bubbles in a triangular lattice. Most unexpectedly, we observe regular helicity reversals inside skyrmions with an unusual multiple-ring structure.

  10. Multiple Memory Structure Bit Reversal Algorithm Based on Recursive Patterns of Bit Reversal Permutation

    Directory of Open Access Journals (Sweden)

    K. K. L. B. Adikaram

    2014-01-01

    Full Text Available With the increasing demand for online/inline data processing efficient Fourier analysis becomes more and more relevant. Due to the fact that the bit reversal process requires considerable processing time of the Fast Fourier Transform (FFT algorithm, it is vital to optimize the bit reversal algorithm (BRA. This paper is to introduce an efficient BRA with multiple memory structures. In 2009, Elster showed the relation between the first and the second halves of the bit reversal permutation (BRP and stated that it may cause serious impact on cache performance of the computer, if implemented. We found exceptions, especially when the said index mapping was implemented with multiple one-dimensional memory structures instead of multidimensional or one-dimensional memory structure. Also we found a new index mapping, even after the recursive splitting of BRP into equal sized slots. The four-array and the four-vector versions of BRA with new index mapping reported 34% and 16% improvement in performance in relation to similar versions of Linear BRA of Elster which uses single one-dimensional memory structure.

  11. A reversible nanoconfined chemical reaction.

    Science.gov (United States)

    Nielsen, Thomas K; Bösenberg, Ulrike; Gosalawit, Rapee; Dornheim, Martin; Cerenius, Yngve; Besenbacher, Flemming; Jensen, Torben R

    2010-07-27

    Hydrogen is recognized as a potential, extremely interesting energy carrier system, which can facilitate efficient utilization of unevenly distributed renewable energy. A major challenge in a future "hydrogen economy" is the development of a safe, compact, robust, and efficient means of hydrogen storage, in particular, for mobile applications. Here we report on a new concept for hydrogen storage using nanoconfined reversible chemical reactions. LiBH4 and MgH2 nanoparticles are embedded in a nanoporous carbon aerogel scaffold with pore size Dmax approximately 21 nm and react during release of hydrogen and form MgB2. The hydrogen desorption kinetics is significantly improved compared to bulk conditions, and the nanoconfined system has a high degree of reversibility and stability and possibly also improved thermodynamic properties. This new scheme of nanoconfined chemistry may have a wide range of interesting applications in the future, for example, within the merging area of chemical storage of renewable energy.

  12. Reverse osmosis water purification system

    Science.gov (United States)

    Ahlstrom, H. G.; Hames, P. S.; Menninger, F. J.

    1986-01-01

    A reverse osmosis water purification system, which uses a programmable controller (PC) as the control system, was designed and built to maintain the cleanliness and level of water for various systems of a 64-m antenna. The installation operates with other equipment of the antenna at the Goldstone Deep Space Communication Complex. The reverse osmosis system was designed to be fully automatic; with the PC, many complex sequential and timed logic networks were easily implemented and are modified. The PC monitors water levels, pressures, flows, control panel requests, and set points on analog meters; with this information various processes are initiated, monitored, modified, halted, or eliminated as required by the equipment being supplied pure water.

  13. Reversible Watermarking Using Statistical Information

    Directory of Open Access Journals (Sweden)

    Kurugollu Fatih

    2010-01-01

    Full Text Available In most reversible watermarking methods, a compressed location map is exploited in order to ensure reversibility. Besides, in some methods, a header containing critical information is appended to the payload for the extraction and recovery process. Such schemes have a highly fragile nature; that is, changing a single bit in watermarked data may prohibit recovery of the original host as well as the embedded watermark. In this paper, we propose a new scheme in which utilizing a compressed location map is completely removed. In addition, the amount of auxiliary data is decreased by employing the adjacent pixels information. Therefore, in addition to quality improvement, independent authentication of different regions of a watermarked image is possible.

  14. Molecular Simulation of Reverse Micelles

    Science.gov (United States)

    Chowdhary, Janamejaya; Ladanyi, Branka

    2009-03-01

    Reverse micelles (RM) are surfactant assemblies containing a nanosized water pool dissolved in a hydrophobic solvent. Understanding their properties is crucial for insight into the effect of confinement on aqueous structure, dynamics as well as physical processes associated with solutes in confinement. We perform molecular dynamics simulations for the RM formed by the surfactant Aerosol-OT (AOT) in isooctane (2,2,4-trimethyl pentane) in order to study the effect of reverse micelle size on the aqueous phase. The structure of the RM is quantified in terms of the radial and pair density distributions. Dynamics are studied in terms of the mean squared displacements and various orientational time correlation functions in different parts of the RM so as to understand the effect of proximity to the interface on aqueous dynamics. Shape fluctuations of the RM are also analyzed.

  15. Reversal agents in anaesthesia and critical care

    Directory of Open Access Journals (Sweden)

    Nibedita Pani

    2015-01-01

    Full Text Available Despite the advent of short and ultra-short acting drugs, an in-depth knowledge of the reversal agents used is a necessity for any anaesthesiologist. Reversal agents are defined as any drug used to reverse the effects of anaesthetics, narcotics or potentially toxic agents. The controversy on the routine reversal of neuromuscular blockade still exists. The advent of newer reversal agents like sugammadex have made the use of steroidal neuromuscular blockers like rocuronium feasible in rapid sequence induction situations. We made a review of the older reversal agents and those still under investigation for drugs that are regularly used in our anaesthesia practice.

  16. Reverse logistics and closed-loop supply chain

    DEFF Research Database (Denmark)

    Govindan, Kannan; Soleimani, Hamed; Kannan, Devika

    2015-01-01

    Based on environmental, legal, social, and economic factors, reverse logistics and closed-loop supply chain issues have attracted attention among both academia and practitioners. This attention is evident by the vast number of publications in scientific journals which have been published in recent...... years. Hence, a comprehensive literature review of recent and state-of-the-art papers is vital to draw a framework of the past, and to shed light on future directions. The aim of this paper is to review recently published papers in reverse logistic and closed-loop supply chain in scientific journals...

  17. Steering Multiple Reverse Current into Unidirectional Current in Deterministic Ratchets

    Institute of Scientific and Technical Information of China (English)

    韦笃取; 罗晓曙; 覃英华

    2011-01-01

    Recent investigations have shown that with varying the amplitude of the external force, the deterministic ratchets exhibit multiple current reversals, which are undesirable in certain circumstances. To control the multiple reverse current to unidirectional current, an adaptive control law is presented inspired from the relation between multiple reversaJs current and the chaos-periodic/quasiperiodic transition of the transport velocity. The designed controller can stabilize the transport velocity of ratchets to steady state and suppress any chaos-periodic/quasiperiodic transition, namely, the stable transport in ratchets is achieved, which makes the current sign unchanged.

  18. CONCEPTUAL ISSUES REGARDING REVERSE LOGISTICS

    Directory of Open Access Journals (Sweden)

    Ioana Olariu

    2014-01-01

    Full Text Available As the power of consumers is growing, the product return for customer service and customer retention has become a common practice in the competitive market, which propels the recent practice of reverse logistics in companies. Many firms attracted by the value available in the flow, have proactively participated in handling returned products at the end of their usefulness or from other parts of the product life cycle. Reverse logistics is the flow and management of products, packaging, components and information from the point of consumption to the point of origin. It is a collection of practices similar to those of supply chain management, but in the opposite direction, from downstream to upstream. It involves activities such as reuse, repair, remanufacture, refurbish, reclaim and recycle. For the conventional forward logistics systems, the flow starts upstream as raw materials, later as manufactured parts and components to be assembled and continues downstream to reach customers as final products to be disposed once they reach their economic or useful lives. In reverse logistics, the disposed products are pushed upstream to be repaired, remanufactured, refurbished, and disassembled into components to be reused or as raw material to be recycled for later use.

  19. Reversible Oxidative Addition at Carbon.

    Science.gov (United States)

    Eichhorn, Antonius F; Fuchs, Sonja; Flock, Marco; Marder, Todd B; Radius, Udo

    2017-04-07

    The reactivity of N-heterocyclic carbenes (NHCs) and cyclic alkyl amino carbenes (cAACs) with arylboronate esters is reported. The reaction with NHCs leads to the reversible formation of thermally stable Lewis acid/base adducts Ar-B(OR)2 ⋅NHC (Add1-Add6). Addition of cAAC(Me) to the catecholboronate esters 4-R-C6 H4 -Bcat (R=Me, OMe) also afforded the adducts 4-R-C6 H4 Bcat⋅cAAC(Me) (Add7, R=Me and Add8, R=OMe), which react further at room temperature to give the cAAC(Me) ring-expanded products RER1 and RER2. The boronate esters Ar-B(OR)2 of pinacol, neopentylglycol, and ethyleneglycol react with cAAC at RT via reversible B-C oxidative addition to the carbene carbon atom to afford cAAC(Me) (B{OR}2 )(Ar) (BCA1-BCA6). NMR studies of cAAC(Me) (Bneop)(4-Me-C6 H4 ) (BCA4) demonstrate the reversible nature of this oxidative addition process.

  20. Topological reversibility and causality in feed-forward networks

    Energy Technology Data Exchange (ETDEWEB)

    Corominas-Murtra, Bernat; RodrIguez-Caso, Carlos; Sole, Ricard [ICREA-Complex Systems Lab, Universitat Pompeu Fabra (Parc de Recerca Biomedica de Barcelona), Dr Aiguader 88, 08003 Barcelona (Spain); Goni, JoaquIn, E-mail: bernat.corominas@upf.ed [Functional Neuroimaging Laboratory, Department of Neurosciences, Center for Applied Medical Research, University of Navarra, Pamplona (Spain)

    2010-11-15

    Systems whose organization displays causal asymmetry constraints, from evolutionary trees to river basins or transport networks, can often be described in terms of directed paths on a discrete set of arbitrary units including states in state spaces, feed-forward neural nets, the evolutionary history of a given collection of events or the chart of computational states visited along a complex computation. Such a set of paths defines a feed-forward, acyclic network. A key problem associated with these systems involves characterizing their intrinsic degree of path reversibility: given an end node in the graph, what is the uncertainty of recovering the process backwards until the origin? Here, we propose a novel concept, topological reversibility, which is a measure of the complexity of the net that rigorously weights such uncertainty in path dependency, quantifying the minimum amount of information required to successfully reverse a causal path. Within the proposed framework, we also analytically characterize limit cases for both topologically reversible and maximally entropic structures. The relevance of these measures within the context of evolutionary dynamics is highlighted.

  1. Magnetization reversal in ultrashort magnetic field pulses

    CERN Document Server

    Bauer, M; Fassbender, J; Hillebrands, B

    2000-01-01

    We report the switching properties of a thin magnetic film subject to an ultrashort, laterally localized magnetic field pulse, obtained by numerical investigations. The magnetization distribution in the film is calculated on a grid assuming Stoner-like coherent rotation within the grid square size. Perpendicularly and in-plane magnetized films exhibit a magnetization reversal due to a 4 ps magnetic field pulse. Outside the central region the pulse duration is short compared to the precession period. In this area the evolution of the magnetization during the field pulse does not depend strongly on magnetic damping and/or pulse shape. However, the final magnetization distribution is affected by the magnetic damping. Although the pulse duration is short compared to the precession period, the time needed for the relaxation of the magnetization to the equilibrium state is rather large. The influence of the different magnetic anisotropy contributions and the magnetic damping parameter enters into the magnetization ...

  2. A reversible optical to microwave quantum interface

    CERN Document Server

    Barzanjeh, Sh; Milburn, G J; Tombesi, P; Vitali, D

    2011-01-01

    Quantum technology, like many mature classical technologies, will ultimately integrate distinct modules to achieve a function that transcends the capability of any one of them. We describe a reversible quantum interface between an optical and a microwave photon using a hybrid device based on the common interaction of microwave and optical fields with a nano-mechanical resonator in a superconducting circuit, which is one of the major challenges in the field. The scheme provides a path for generating a traveling microwave field strongly entangled with an optical mode, thus bridging the gap between quantum optical and solid state implementations of quantum information. This is an effective source of (bright) two-mode squeezing with an optical idler (signal) and a microwave signal (idler) and as such enables a continuous variable teleportation protocol.

  3. MicroPower - Towards Low-power Microprocessors with Reversible Computing

    DEFF Research Database (Denmark)

    Axelsen, Holger Bock; Glück, Robert; De Vos, Alexis

    2009-01-01

    Physics tells us that at the microscopic level the evolution of a (micro-) state is reversible, ie deterministic both forward and backward in time. In contrast, our best models of computation are usually not reversible at the microscopic level, and this carries over to actual implementations in c...

  4. Reversible electric-field control of magnetization at oxide interfaces

    Science.gov (United States)

    Cuellar, F. A.; Liu, Y. H.; Salafranca, J.; Nemes, N.; Iborra, E.; Sanchez-Santolino, G.; Varela, M.; Hernandez, M. Garcia; Freeland, J. W.; Zhernenkov, M.; Fitzsimmons, M. R.; Okamoto, S.; Pennycook, S. J.; Bibes, M.; Barthélémy, A.; Te Velthuis, S. G. E.; Sefrioui, Z.; Leon, C.; Santamaria, J.

    2014-06-01

    Electric-field control of magnetism has remained a major challenge which would greatly impact data storage technology. Although progress in this direction has been recently achieved, reversible magnetization switching by an electric field requires the assistance of a bias magnetic field. Here we take advantage of the novel electronic phenomena emerging at interfaces between correlated oxides and demonstrate reversible, voltage-driven magnetization switching without magnetic field. Sandwiching a non-superconducting cuprate between two manganese oxide layers, we find a novel form of magnetoelectric coupling arising from the orbital reconstruction at the interface between interfacial Mn spins and localized states in the CuO2 planes. This results in a ferromagnetic coupling between the manganite layers that can be controlled by a voltage. Consequently, magnetic tunnel junctions can be electrically toggled between two magnetization states, and the corresponding spin-dependent resistance states, in the absence of a magnetic field.

  5. Garbageless reversible implementation of integer linear transformations

    DEFF Research Database (Denmark)

    Burignat, Stéphane; Vermeirsch, Kenneth; De Vos, Alexis;

    2013-01-01

    Discrete linear transformations are important tools in information processing. Many such transforms are injective and therefore prime candidates for a physically reversible implementation into hardware. We present here reversible digital implementations of different integer transformations on fou...

  6. Reversible logic gate using adiabatic superconducting devices

    National Research Council Canada - National Science Library

    Takeuchi, N; Yamanashi, Y; Yoshikawa, N

    2014-01-01

    .... However, until now, no practical reversible logic gates have been demonstrated. One of the problems is that reversible logic gates must be built by using extremely energy-efficient logic devices...

  7. 14 CFR 33.97 - Thrust reversers.

    Science.gov (United States)

    2010-01-01

    ... Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: AIRCRAFT ENGINES Block Tests; Turbine Aircraft Engines § 33.97 Thrust reversers. (a) If the engine incorporates a reverser, the endurance calibration, operation, and vibration tests prescribed...

  8. SELECTED PROBLEMS OF REVERSE LOGISTICS IN POLAND

    OpenAIRE

    Agata Mesjasz-Lech

    2009-01-01

    This paper presents the essence of reverse logistics and directions of physical and information flows between logistic network partners. It also analyses effects of implementation of the principles of reverse logistics in Poland in the years 2004-2007

  9. Design of a High Performance Reversible Multiplier

    Directory of Open Access Journals (Sweden)

    Md.Belayet Ali

    2011-11-01

    Full Text Available Reversible logic circuits are increasingly used in power minimization having applications such as low power CMOS design, optical information processing, DNA computing, bioinformatics, quantum computing and nanotechnology. The problem of minimizing the number of garbage outputs is an important issue in reversible logic design. In this paper we propose a new 44 universal reversible logic gate. The proposed reversible gate can be used to synthesize any given Boolean functions. The proposed reversible gate also can be used as a full adder circuit. In this paper we have used Peres gate and the proposed Modified HNG (MHNG gate to construct the reversible fault tolerant multiplier circuit. We show that the proposed 44 reversible multiplier circuit has lower hardware complexity and it is much better and optimized in terms of number of reversible gates and number of garbage outputs with compared to the existing counterparts.

  10. Real-world experience with neuromuscular blockade reversal.

    Science.gov (United States)

    Groudine, Scott B; Minkowitz, Harold S; Valentine, Danny L

    2017-11-01

    Neuromuscular blocking agents are used in many surgical procedures and have enabled new surgical advances. The expanded landscape of neuromuscular blockade (NMB) reversal drugs allows for fast and complete NMB reversal and the reduction of postoperative complications from residual block. In the United States, neostigmine/glycopyrrolate and sugammadex are the primary agents for pharmacologic antagonism of neuromuscular blocking agents. Whereas neostigmine and an anticholinergic have been available for decades, sugammadex has only recently become available. We present real-world cases in a variety of surgical procedures and clinical settings in which the use of NMB reversal agents played a significant role in the patients’ clinical outcome. Online access: http://courses.elseviercme.com/nmb/711.

  11. Mitochondrial ROS Produced via Reverse Electron Transport Extend Animal Lifespan.

    Science.gov (United States)

    Scialò, Filippo; Sriram, Ashwin; Fernández-Ayala, Daniel; Gubina, Nina; Lõhmus, Madis; Nelson, Glyn; Logan, Angela; Cooper, Helen M; Navas, Plácido; Enríquez, Jose Antonio; Murphy, Michael P; Sanz, Alberto

    2016-04-12

    Increased production of reactive oxygen species (ROS) has long been considered a cause of aging. However, recent studies have implicated ROS as essential secondary messengers. Here we show that the site of ROS production significantly contributes to their apparent dual nature. We report that ROS increase with age as mitochondrial function deteriorates. However, we also demonstrate that increasing ROS production specifically through respiratory complex I reverse electron transport extends Drosophila lifespan. Reverse electron transport rescued pathogenesis induced by severe oxidative stress, highlighting the importance of the site of ROS production in signaling. Furthermore, preventing ubiquinone reduction, through knockdown of PINK1, shortens lifespan and accelerates aging; phenotypes that are rescued by increasing reverse electron transport. These results illustrate that the source of a ROS signal is vital in determining its effects on cellular physiology and establish that manipulation of ubiquinone redox state is a valid strategy to delay aging.

  12. Enhancing teleportation fidelity by means of weak measurements or reversal

    Energy Technology Data Exchange (ETDEWEB)

    Qiu, Liang, E-mail: lqiu@cumt.edu.cn [College of Sciences, China University of Mining and Technology, Xuzhou 221116 (China); Tang, Gang; Yang, Xianqing [College of Sciences, China University of Mining and Technology, Xuzhou 221116 (China); Wang, Anmin [Department of Modern Physics, University of Science and Technology of China, Hefei 230026 (China)

    2014-11-15

    The enhancement of teleportation fidelity by weak measurement or quantum measurement reversal is investigated. One qubit of a maximally entangled state undergoes the amplitude damping, and the subsequent application of weak measurement or quantum measurement reversal could improve the teleportation fidelity beyond the classical region. The improvement could not be attributed to the increasing of entanglement, quantum discord, classical correlation or total correlation. We declare that it should be owed to the probabilistic nature of the method. - Highlights: • The method’s probabilistic nature should be responsible for the improvement. • Quantum or classical correlation cannot explain the improvement. • The receiver cannot apply weak measurements. • The sender’s quantum measurement reversal is only useful for |Ψ{sup ±}〉.

  13. Design of High speed Low Power Reversible Vedic multiplier and Reversible Divider

    Directory of Open Access Journals (Sweden)

    Srikanth G Department of Electronics & Communication Engineerig, Indur Institute of Engineering & Technology, Siddipet, Medak, JNTUH University, Telangana, India.

    2014-09-01

    Full Text Available This paper bring out a 32X32 bit reversible Vedic multiplier using "Urdhva Tiryakabhayam" sutra meaning vertical and crosswise, is designed using reversible logic gates, which is the first of its kind. Also in this paper we propose a new reversible unsigned division circuit. This circuit is designed using reversible components like reversible parallel adder, reversible left-shift register, reversible multiplexer, reversible n-bit register with parallel load line. The reversible vedic multiplier and reversible divider modules have been written in Verilog HDL and then synthesized and simulated using Xilinx ISE 9.2i. This reversible vedic multiplier results shows less delay and less power consumption by comparing with array multiplier.

  14. Statistical Learning, Letter Reversals, and Reading

    Science.gov (United States)

    Treiman, Rebecca; Gordon, Jessica; Boada, Richard; Peterson, Robin L.; Pennington, Bruce F.

    2014-01-01

    Reversal errors play a prominent role in theories of reading disability. We examined reversal errors in the writing of letters by 5- to 6-year-old children. Of the 130 children, 92 had a history of difficulty in producing speech sounds, a risk factor for reading problems. Children were more likely to reverse letter forms that face left, such as…

  15. Garbage collection for reversible functional languages

    DEFF Research Database (Denmark)

    Mogensen, Torben Ægidius

    2015-01-01

    Reversible languages are programming languages where all programs can run both forwards and backwards. Reversible functional languages have been proposed that use symmetric pattern matching and data construction. To be reversible, these languages require linearity: Every variable must be used exa...

  16. A functional language for describing reversible logic

    DEFF Research Database (Denmark)

    Thomsen, Michael Kirkedal

    2012-01-01

    . Reversibility of descriptions is guaranteed with a type system based on linear types. The language is applied to three examples of reversible computations (ALU, linear cosine transformation, and binary adder). The paper also outlines a design flow that ensures garbage- free translation to reversible logic...

  17. THEORETICAL FRAMES FOR DESIGNING REVERSE LOGISTICS PROCESSES

    OpenAIRE

    Grabara, Janusz K.; Sebastian Kot

    2009-01-01

    Logistics processes of return flow became more and more important in present business practice. Because of better customer satisfaction, environmental and financial aspects many enterprises deal with reverse logistics performance. The paper is a literature review focused on the design principles of reverse logistics processes Keywords: reverse logistics, designing.

  18. Dynamic Reverse Code Generation for Backward Execution

    DEFF Research Database (Denmark)

    Lee, Jooyong

    2007-01-01

    . In this paper, we present a method to generate reverse code, so that backtracking can be performed by executing reverse code. The novelty of our work is that we generate reverse code on-the-fly, while running a debugger, which makes it possible to apply the method even to debugging multi-threaded programs....

  19. Cleaning Our World through Reverse Graffiti

    Science.gov (United States)

    Randazzo, Gabe; LaJevic, Lisa

    2013-01-01

    Over the last decade artists have begun to experiment with "reverse pollution" techniques, such as reverse graffiti, which focuses on cleaning environmental surfaces. Having recently been introduced to the works of Moose, the artist known for inventing the reverse graffiti technique, the authors decided to design a curriculum to increase…

  20. REVERSE ENGINEERING AND ITS REALISTIC APPLICATIONS

    OpenAIRE

    Nikita Bakshi; Shruti Gujral

    2014-01-01

    Reverse-engineering is used for many purposes like as a learning tool, as a way to make compatible products that are cheaper than what is currently on the market. This paper discusses what is software, its type, reverse engineering, applications of reverse engineering and their tools.

  1. REVERSE ENGINEERING AND ITS REALISTIC APPLICATIONS

    Directory of Open Access Journals (Sweden)

    Nikita Bakshi

    2014-06-01

    Full Text Available Reverse-engineering is used for many purposes like as a learning tool, as a way to make compatible products that are cheaper than what is currently on the market. This paper discusses what is software, its type, reverse engineering, applications of reverse engineering and their tools.

  2. Remote Whispering Applying Time Reversal

    Energy Technology Data Exchange (ETDEWEB)

    Anderson, Brian Eric [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2015-07-16

    The purpose of this project was to explore the use of time reversal technologies as a means for communication to a targeted individual or location. The idea is to have the privacy of whispering in one’s ear, but to do this remotely from loudspeakers not located near the target. Applications of this work include communicating with hostages and survivors in rescue operations, communicating imaging and operational conditions in deep drilling operations, monitoring storage of spent nuclear fuel in storage casks without wires, or clandestine activities requiring signaling between specific points. This technology provides a solution in any application where wires and radio communications are not possible or not desired. It also may be configured to self calibrate on a regular basis to adjust for changing conditions. These communications allow two people to converse with one another in real time, converse in an inaudible frequency range or medium (i.e. using ultrasonic frequencies and/or sending vibrations through a structure), or send information for a system to interpret (even allowing remote control of a system using sound). The time reversal process allows one to focus energy to a specific location in space and to send a clean transmission of a selected signal only to that location. In order for the time reversal process to work, a calibration signal must be obtained. This signal may be obtained experimentally using an impulsive sound, a known chirp signal, or other known signals. It may also be determined from a numerical model of a known environment in which the focusing is desired or from passive listening over time to ambient noise.

  3. Reverse Triangle Inequalities for Potentials

    OpenAIRE

    Pritsker, I. E.; Saff, E. B.

    2013-01-01

    We study the reverse triangle inequalities for suprema of logarithmic potentials on compact sets of the plane. This research is motivated by the inequalities for products of supremum norms of polynomials. We find sharp additive constants in the inequalities for potentials, and give applications of our results to the generalized polynomials. We also obtain sharp inequalities for products of norms of the weighted polynomials $w^nP_n, deg(P_n)\\le n,$ and for sums of suprema of potentials with ex...

  4. Presbycusis: reversible with anesthesia drugs?

    Science.gov (United States)

    Kocher, Carl A

    2009-02-01

    Age-related hearing impairment, or presbycusis, is a degenerative condition not currently treatable by medication. It is therefore significant that the author, as a patient, experienced a reversal of high-frequency hearing loss during a 2-day period following abdominal surgery with general anesthesia. This report documents the surgery and the subsequent restoration of hearing, which was bilateral and is estimated to have exceeded 50dB at 4kHz. A possible role is noted for anesthetic agents such as lidocaine, propofol, or fentanyl. This experience may hold a clue for research toward the development of medical treatments for presbycusis.

  5. How to play Reverse Hex

    DEFF Research Database (Denmark)

    Toft, Bjarne; Hayward, Ryan B.; Henderson, Philip

    2012-01-01

    We present new results on how to play Reverse Hex, also known as Rex, or Misère Hex, on n × n boards. We give new proofs – and strengthened versions – of Lagarias and Sleator’s theorem (for n × n boards, each player can prolong the game until the board is full, so the first/second player can always......, we find second-player winning replies. Finally, in response to comments by Martin Gardner, for each n ≤ 5, we give a simple winning strategy for the n × n board....

  6. Order from disorder in closed systems via time reversal violation

    CERN Document Server

    Goldman, T

    2012-01-01

    Definitions of entropy usually assume time-reversal (T) invariance of interactions, yet microscopically T is known to be violated. We present a detailed computational example of (uncharged) particle species separation (Maxwell demon) using an interaction that violates both parity (P) and T so that PT is preserved, consistent with the CPT invariance required in quantum field theory (C is charge conjugation). This illustrates how T-violating forces can produce more organized states from disorganized ones, contrary to expectations based on increase of entropy. We also outline several scenarios in which T-violating forces could lead to an organized state in the early Universe, starting from a still earlier disorganized state.

  7. A trivial observation on time reversal in random matrix theory

    Energy Technology Data Exchange (ETDEWEB)

    Kaplan, L [Department of Physics, Tulane University, New Orleans, LA (United States); Leyvraz, F [Instituto de Ciencias Fisicas, Universidad Nacional Autonoma de Mexico (Mexico); Pineda, C [Instituto de Ciencias Fisicas, Universidad Nacional Autonoma de Mexico (Mexico); Seligman, T H [Instituto de Ciencias Fisicas, Universidad Nacional Autonoma de Mexico (Mexico)

    2007-12-07

    It is commonly thought that a state-dependent quantity, after being averaged over a classical ensemble of random Hamiltonians, will always become independent of the state. We point out that this is in general incorrect: if the ensemble of Hamiltonians is time-reversal invariant, and the quantity involves the state in higher than bilinear order, then we show that the quantity is only a constant over the orbits of the invariance group on the Hilbert space. Examples include fidelity and decoherence in appropriate models. (fast track communication)

  8. Optimized reversible binary-coded decimal adders

    DEFF Research Database (Denmark)

    Thomsen, Michael Kirkedal; Glück, Robert

    2008-01-01

    their design. The optimized 1-decimal BCD full-adder, a 13 × 13 reversible logic circuit, is faster, and has lower circuit cost and less garbage bits. It can be used to build a fast reversible m-decimal BCD full-adder that has a delay of only m + 17 low-power reversible CMOS gates. For a 32-decimal (128-bit...... in reversible logic design by drastically reducing the number of garbage bits. Specialized designs benefit from support by reversible logic synthesis. All circuit components required for optimizing the original design could also be synthesized successfully by an implementation of an existing synthesis algorithm...

  9. Reversing invasion in bistable systems.

    Science.gov (United States)

    Alzahrani, Ebraheem O; Davidson, Fordyce A; Dodds, Niall

    2012-12-01

    In this paper, we discuss a class of bistable reaction-diffusion systems used to model the competitive interaction of two species. The interactions are assumed to be of classic "Lotka-Volterra" type and we will consider a particular problem with relevance to applications in population dynamics: essentially, we study under what conditions the interplay of relative motility (diffusion) and competitive strength can cause waves of invasion to be halted and reversed. By establishing rigorous results concerning related degenerate and near-degenerate systems, we build a picture of the dependence of the wave speed on system parameters. Our results lead us to conjecture that this class of competition model has three "zones of response". In the central zone, varying the motility can slow, halt and reverse invasion. However, in the two outer zones, the direction of invasion is independent of the relative motility and is entirely determined by the relative competitive strengths. Furthermore, we conjecture that for a large class of competition models of the type studied here, the wave speed is an increasing function of the relative motility.

  10. Reverse Genetic Approaches in Zebrafish

    Institute of Scientific and Technical Information of China (English)

    Peng Huang; Zuoyan Zhu; Shuo Lin; Bo Zhang

    2012-01-01

    Zebrafish (Danio rerio) is a well-established vertebrate animal model.A comprehensive collection of reverse genetics tools has been developed for studying gene function in this useful organism.Morpholino is the most widely used reagent to knock down target gene expression post-transcriptionally.For a long time,targeted genome modification has been heavily relied on large-scale traditional forward genetic screens,such as ENU (N-ethyl-N-nitrosourea) mutagenesis derived TILLING (Targeting Induced Local Lesions IN Genomes)strategy and pseudo-typed retrovirus mediated insertional mutagenesis.Recently,engineered endonucleases,including ZFNs (zinc finger nucleases) and TALENs (transcription activator-like effector nucleases),provide new and efficient strategies to directly generate sitespecific indel mutations by inducing double strand breaks in target genes.Here we summarize the major reverse genetic approaches for loss-of-function studies used and emerging in zebrafish,including strategies based on genome-wide mutagenesis and methods for sitespecific gene targeting.Future directions and expectations will also be discussed.

  11. An Area Efficient and High Speed Reversible Multiplier Using NS Gate

    Directory of Open Access Journals (Sweden)

    Venkateswarlu

    2017-01-01

    Full Text Available In digital computer system a major problem has been found that the Power dissipation which leads to bring some research on the methods to decrease this Area efficient, high speed. This is the main cause to give birth to reversible computing systems for digital computers and designs. Reversible computing is the path to future computing technologies, which all happen to use reversible logic. In addition, reversible computing will become mandatory because of the necessity to decrease power consumption. Reversible logic circuits have the same number of inputs and outputs, and have one-to-one mapping between vectors of inputs and outputs; thus the vector of input states can be always reconstructed from the vector of output states. Consequently, a computation is reversible, if it is always possible to uniquely recover the input, given the output. Each gate can be made reversible by adding some additional input and output wires if necessary. The main aim of this reversible computing is to lower the power dissipation, area efficient and high speed and some other advantages like security of data and prevention of errors etc... Reversible logic has so many applications low power CMOS, nanotechnology, DNA computing and quantum computing. There are two primary design implementations in this study which are the major spotlights. The first one is reversible design gate and the second one is multiplier design using reversible gates. In this manuscript we have implemented a 8 * 8 reversible design called “NSG(Non linear Sign Flip”. The total project is implemented in Xilinx 14.7 ISE with Spartan 3E family

  12. Online Testable Decoder using Reversible Logic

    Directory of Open Access Journals (Sweden)

    Hemalatha. K. N. Manjula B. B. Girija. S

    2012-02-01

    Full Text Available The project proposes to design and test 2 to 4 reversible Decoder circuit with arbitrary number of gates to an online testable reversible one and is independent of the type of reversible gate used. The constructed circuit can detect any single bit errors and to convert a decoder circuit that is designed by reversible gates to an online testable reversible decoder circuit. Conventional digital circuits dissipate a significant amount of energy because bits of information are erased during the logic operations. Thus if logic gates are designed such that the information bits are not destroyed, the power consumption can be reduced. The information bits are not lost in case of a reversible computation. Reversible logic can be used to implement any Boolean logic function.

  13. The Policy Context: Reversing a State of Neglect

    Science.gov (United States)

    Velleman, Richard

    2010-01-01

    This article briefly outlines the neglect of families within previous UK policy documents relating to drugs and alcohol, and discusses the significant progress that has been made in focusing on the family over the past decade. Although substance misuse causes major problems for many family members, this was not even recognized across the Western…

  14. Molecular programming of steady-state dendritic cells: impact on autoimmunity and tumor immune surveillance.

    Science.gov (United States)

    Johnson, Dylan J; Ohashi, Pamela S

    2013-05-01

    Dendritic cells are master regulators of immunity. Immature dendritic cells are essential for maintaining self-tolerance, while mature dendritic cells initiate a variety of specialized immune responses. Dendritic cell quiescence is often viewed as a default state that requires exogenous stimuli to induce maturation. However, recent studies have identified dendritic cell quiescence factors that actively program dendritic cells to an immature state. In the absence of these factors, dendritic cells spontaneously become immunogenic and can induce autoimmune responses. Herein we discuss two such factors, NF-κB1 and A20, that preserve dendritic cell immaturity through their regulation of NF-κB signaling. Loss of either of these factors increases dendritic cell immunogenicity, suggesting that they may be important targets for enhancing dendritic cell-based cancer immunotherapies. Alternatively, defects in molecules critical for maintaining steady-state DCs may provide novel biomarkers that identify patients who have enhanced natural antitumor immunity or that correlate with better responses to various immunotherapies.

  15. An Optimal Remanufacturing Centre Selection Algorithm for Reverse Logistics Alliance

    Directory of Open Access Journals (Sweden)

    Uzma Hameed

    2013-07-01

    Full Text Available Reverse logistics has been an emerging field both in academic as well as in applied research since last two decades because of increasing consumer awareness, legislative initiatives and profits associated with reuse of products or components. The costs associated with reverse logistics are usually high and these need to be minimized. The current study focuses on the formulation of alliance for cost reductions in reverse logistics. Remanufacturing, refurbishing, repair, cannibalization and reuse are the processes which add value to the reverse logistics system and are capable of converting it into a profitable venture. Used products contribute a cheaper source of components and spares required to remanufacture a product because of the less costs associated with the labor and material resources when compared with the manufacturing of new parts or products. When a defective part is removed from a product or assembly, it can be restored to its original state of functionality. Instead of purchasing a new, the same can be restored from repair/remanufacture centre just replacing defective part with a new part or spare. Furthermore, for manufacturers to reduce investments in reverse logistics, the formations of alliance and sharing of facilities for remanufacturing can lead to more profitability. In this study a focus has been made for the formation of remanufacturing alliance and an algorithm has been formulated for the selection of optimal remanufacturing center for the reverse logistics alliance. A case company has been selected from emerging Chinese electronic manufacturing industry. The case has been solved by using data set of the selected company with the help of formulated algorithm.

  16. Signatures of time reversal symmetry breaking in multiband superconductors

    Science.gov (United States)

    Maiti, Saurabh

    Multiband superconductors serve as natural host to several possible gound states that compete with each other. At the boundaries of such competing phases, the system usually compromises and settles for `mixed' phases that can show intriguing properties like co-existence of magnetism and superconductiivty or even co-existence of different superconducting phases. The latter is particularly interesting as it can lead to non-magnetic ground states that spontaneously break Time-Reversal symmetry. While the experimental verification of such states has proved to been challenging, the theoretical investigations have provided exciting new insights into the nature of the ground state and its excitations all of which have experimental consequences of some sort. These include extrinsic properties like spontaneous currents around impurity sites, and intrinsic properties in the form of collective excitations. These collective modes bear a unique signature and should provide clear evidence for time reversal symmetry broken state. While the results are general, in light of recent Raman scattering experiments, its direct relevance to extremely hole doped Ba(1-x)K(FeAs)2 will be presented where a strong competition of s-wave and d-wave ground state is expected.

  17. Monitoring Chandra observations of the quasi-persistent neutron-star X-ray transient MXB 1659-29 in quiescence: the cooling curve of the heated neutron-star crust

    CERN Document Server

    Wijnands, R; Miller, J M; Lewin, W H G; Wijnands, Rudy; Homan, Jeroen; Miller, Jon M.; Lewin, Walter H. G.

    2004-01-01

    We have observed the quasi-persistent neutron-star X-ray transient and eclipsing binary MXB 1659-29 in quiescence on three occasions with Chandra. The purpose of our observations was to monitor the quiescent behavior of the source after its last prolonged (~2.5 years) outburst which ended in September 2001. The X-ray spectra of the source are consistent with thermal radiation from the neutron-star surface. We found that the bolometric flux of the source decreased by a factor of 7-9 over the time-span of 1.5 years between our first and last Chandra observations. The effective temperature also decreased, but by a factor of 1.6-1.7. The decrease in time of the bolometric flux and effective temperature can be described using exponential decay functions, with e-folding times of ~0.7 and ~3 years, respectively. Our results are consistent with the hypothesis that we observed a cooling neutron-star crust which was heated considerably during the prolonged accretion event and which is still out of thermal equilibrium w...

  18. Aspect-ratio dependence of magnetization reversal in cylindrical ferromagnetic nanowires

    Science.gov (United States)

    Sultan, Musaab S.; Atkinson, Del

    2016-05-01

    The magnetization reversal behavior in isolated cylindrical and square cross-section Ni81Fe19 nanowires was systematically studied as a function of nanowire cross-section dimensions from 10 up to 200 nm using micromagnetic simulations. This approach provides access to the switching field, remanence ratio and most significantly the magnetization structures during reversal, which allows the evolution of magnetization processes to be studied with scaling of the cross-sectional dimensions. The dimensional trends in reversal behavior for both square and circular cross-section were comparable throughout the range of dimensions studied. The thinnest nanowires showed simple square switching and 100% remanence. With increasing diameter the switching field reduces and above 40 nm the reversal behavior shows an increasing rotational component prior to sharp switching of the magnetization. The magnitude of the reversible component increases with increasing dimensions up to 150 nm, above which the magnetization reversal process is more complicated and the hysteresis loops are no longer bistable. The micromagnetic structures evolve from simple uniform parallel single domain states in the thinnest wires through the formation of vortex-like end states in thicker wires to complex multidomain structures during the reversal of the thickest wires. In the later cases the reversal is not simple curling-like behavior, although the angular switching field dependence was comparable with curling.

  19. Principles of a reversible programming language

    DEFF Research Database (Denmark)

    Yokoyama, Tetsuo; Axelsen, Holger Bock; Glück, Robert

    2008-01-01

    The principles of reversible programming languages are explicated and illustrated with reference to the design of a high-level imperative language, Janus. The fundamental properties for such languages include backward as well as forward determinism and reversible updates of data. The unique design...... features of the language include explicit post-condition assertions, direct access to an inverse semantics and the possibility of clean (i.e., garbage-free) computation of injective functions. We suggest the clean simulation of reversible Turing machines as a criterion for computing strength of reversible...... languages, and demonstrate this for Janus. We show the practicality of the language by implementation of a reversible fast Fourier transform. Our results indicate that the reversible programming paradigm has fundamental properties that are relevant to many different areas of computer science....

  20. Securing Biometric Images using Reversible Watermarking

    CERN Document Server

    Thampi, Sabu M

    2011-01-01

    Biometric security is a fast growing area. Protecting biometric data is very important since it can be misused by attackers. In order to increase security of biometric data there are different methods in which watermarking is widely accepted. A more acceptable, new important development in this area is reversible watermarking in which the original image can be completely restored and the watermark can be retrieved. But reversible watermarking in biometrics is an understudied area. Reversible watermarking maintains high quality of biometric data. This paper proposes Rotational Replacement of LSB as a reversible watermarking scheme for biometric images. PSNR is the regular method used for quality measurement of biometric data. In this paper we also show that SSIM Index is a better alternate for effective quality assessment for reversible watermarked biometric data by comparing with the well known reversible watermarking scheme using Difference Expansion.

  1. Reverse-symmetry waveguides: Theory and fabrication

    DEFF Research Database (Denmark)

    Horvath, R.; Lindvold, Lars René; Larsen, N.B.

    2002-01-01

    We present an extensive theoretical analysis of reverse-symmetry waveguides with special focus on their potential application as sensor components in aqueous media and demonstrate a novel method for fabrication of such waveguides. The principle of reverse symmetry is based on making the refractiv...... has the advantage of deeper penetration of the evanescent electromagnetic field into the cover medium, theoretically permitting higher sensitivity to analytes compared to traditional waveguide designs. We present calculated sensitivities and probing depths of conventional and reverse...

  2. Magnetic field reversals and galactic dynamos

    OpenAIRE

    2012-01-01

    We argue that global magnetic field reversals similar to those observed in the Milky Way occur quite frequently in mean-field galactic dynamo models that have relatively strong, random, seed magnetic fields that are localized in discrete regions. The number of reversals decreases to zero with reduction of the seed strength, efficiency of the galactic dynamo and size of the spots of the seed field. A systematic observational search for magnetic field reversals in a representative sample of spi...

  3. Long-acting reversible contraceptives: intrauterine devices and the contraceptive implant.

    Science.gov (United States)

    Espey, Eve; Ogburn, Tony

    2011-03-01

    The provision of effective contraception is fundamental to the practice of women's health care. The most effective methods of reversible contraception are the so-called long-acting reversible contraceptives, intrauterine devices and implants. These methods have multiple advantages over other reversible methods. Most importantly, once in place, they do not require maintenance and their duration of action is long, ranging from 3 to 10 years. Despite the advantages of long-acting reversible contraceptive methods, they are infrequently used in the United States. Short-acting methods, specifically oral contraceptives and condoms, are by far the most commonly used reversible methods. A shift from the use of short-acting methods to long-acting reversible contraceptive methods could help reduce the high rate of unintended pregnancy in the United States. In this review of long-acting reversible contraceptive methods, we discuss the intrauterine devices and the contraceptive implant available in the United States, and we describe candidates for each method, noncontraceptive benefits, and management of complications.

  4. Reversibility of Sympathectomy for Primary Hyperhidrosis.

    Science.gov (United States)

    Hynes, Conor F; Marshall, M Blair

    2016-11-01

    Endoscopic thoracic sympathectomy (ETS) is an effective treatment of primary hyperhidrosis of the face, upper extremities, and axillae. The major limitation is the side effect of compensatory sweating severe enough that patients request reversal in up to 10% of cases. When ETS is performed by cutting the sympathetic chain, reversal requires nerve grafting. However, for ETS done with clips, reversal is a simple thoracoscopic outpatient procedure of removing the clips. Subsequent reversal of the sympathectomy, ie, nerve regeneration, is successful in many cases. However, follow-up is short. Factors contributing to success rates require further study. Copyright © 2016 Elsevier Inc. All rights reserved.

  5. Delay Reduction in Optimized Reversible Multiplier Circuit

    Directory of Open Access Journals (Sweden)

    Mohammad Assarian

    2012-01-01

    Full Text Available In this study a novel reversible multiplier is presented. Reversible logic can play a significant role in computer domain. This logic can be applied in quantum computing, optical computing processing, DNA computing, and nanotechnology. One condition for reversibility of a computable model is that the number of input equate with the output. Reversible multiplier circuits are the circuits used frequently in computer system. For this reason, optimization in one reversible multiplier circuit can reduce its volume of hardware on one hand and increases the speed in a reversible system on the other hand. One of the important parameters that optimize a reversible circuit is reduction of delays in performance of the circuit. This paper investigates the performance characteristics of the gates, the circuits and methods of optimizing the performance of reversible multiplier circuits. Results showed that reduction of the reversible circuit layers has lead to improved performance due to the reduction of the propagation delay between input and output period. All the designs are in the nanometric scales.

  6. Combining or Separating Forward and Reverse Logistics

    DEFF Research Database (Denmark)

    Herbert-Hansen, Zaza Nadja Lee; Larsen, Samuel; Nielsen, Anders

    2017-01-01

    Purpose – While forward logistics handles and manages the flow of goods downstream in the supply chain from suppliers to customers, reverse logistics (RL) manages the flow of returned goods upstream. A firm can combine reverse logistics with forward logistics, keep the flows separated, or choose......-research addresses intra-RL issues while the relationship between forward and reverse logistics is under-researched. This paper contributes to RL-theory by identifying the contextual factors that determine the most advantageous relationship between forward and reverse logistics, and proposes a novel decision making...

  7. THRUST REVERSER PERFORMANCE AND THE INGESTION PROBLEM,

    Science.gov (United States)

    THRUST REVERSAL, INGESTION ), (*JET TRANSPORT PLANE, THRUST), (*TURBOJET ENGINES, INGESTION ), JET TRANSPORT PLANES, PELLETS, ROCK (GEOLOGY), PARTICLES, DESIGN, MODEL, INSTALLATION, EFFECTIVENESS, COMMERICAL.

  8. Reverse Genetics Approaches for the Development of Influenza Vaccines

    Directory of Open Access Journals (Sweden)

    Aitor Nogales

    2016-12-01

    Full Text Available Influenza viruses cause annual seasonal epidemics and occasional pandemics of human respiratory disease. Influenza virus infections represent a serious public health and economic problem, which are most effectively prevented through vaccination. However, influenza viruses undergo continual antigenic variation, which requires either the annual reformulation of seasonal influenza vaccines or the rapid generation of vaccines against potential pandemic virus strains. The segmented nature of influenza virus allows for the reassortment between two or more viruses within a co-infected cell, and this characteristic has also been harnessed in the laboratory to generate reassortant viruses for their use as either inactivated or live-attenuated influenza vaccines. With the implementation of plasmid-based reverse genetics techniques, it is now possible to engineer recombinant influenza viruses entirely from full-length complementary DNA copies of the viral genome by transfection of susceptible cells. These reverse genetics systems have provided investigators with novel and powerful approaches to answer important questions about the biology of influenza viruses, including the function of viral proteins, their interaction with cellular host factors and the mechanisms of influenza virus transmission and pathogenesis. In addition, reverse genetics techniques have allowed the generation of recombinant influenza viruses, providing a powerful technology to develop both inactivated and live-attenuated influenza vaccines. In this review, we will summarize the current knowledge of state-of-the-art, plasmid-based, influenza reverse genetics approaches and their implementation to provide rapid, convenient, safe and more effective influenza inactivated or live-attenuated vaccines.

  9. Learning course adjustments during arm movements with reversed sensitivity derivatives

    Directory of Open Access Journals (Sweden)

    Tweed Douglas B

    2010-11-01

    Full Text Available Abstract Background To learn, a motor system needs to know its sensitivity derivatives, which quantify how its neural commands affect motor error. But are these derivatives themselves learned, or are they known solely innately? Here we test a recent theory that the brain's estimates of sensitivity derivatives are revisable based on sensory feedback. In its simplest form, the theory says that each control system has a single, adjustable estimate of its sensitivity derivatives which affects all aspects of its task, e.g. if you learn to reach to mirror-reversed targets then your revised estimate should reverse not only your initial aiming but also your online course adjustments when the target jumps in mid-movement. Methods Human subjects bent a joystick to move a cursor to a target on a computer screen, but the cursor's motion was reversed relative to the joystick's. The target jumped once during each movement. Subjects had up to 4000 trials to practice aiming and responding to target jumps. Results All subjects learned to reverse both initial aiming and course adjustments. Conclusions Our study confirms that sensitivity derivatives can be relearned. It is consistent with the idea of a single, all-purpose estimate of those derivatives; and it suggests that the estimate is a function of context, as one would expect given that the true sensitivity derivatives may vary with the state of the controlled system, the target, and the motor commands.

  10. Remagnetization of lava flows spanning the last geomagnetic reversal

    Science.gov (United States)

    Vella, Jérôme; Carlut, Julie; Valet, Jean-Pierre; Goff, Maxime Le; Soler, Vicente; Lopes, Fernando

    2017-08-01

    Large directional changes of remanent magnetization within lava flows that cooled during geomagnetic reversals have been reported in several studies. A geomagnetic scenario implies extremely rapid geomagnetic changes of several degrees per day, thus difficult to reconcile with the rate of the earth's core liquid motions. So far, no complete rock magnetic model provides a clear explanation. We revisited lava flows sandwiched between an underlying reverse and an overlying normal polarity flow marking the last reversal in three distinct volcanic sequences of the La Palma Island (Canary archipelago, Spain) that are characterized by a gradual evolution of the direction of their remanent magnetization from bottom to top. Cleaning efficiency of thermal demagnetization was not improved by very rapid heating and cooling rates as well as by continuous demagnetization using a Triaxe magnetometer. We did not observe partial self-reversals and minor changes in magnetic grain sizes are not related to the within-flow directional changes. Microscopic observations indicate poor exsolution, which suggests post-cooling thermochemical remagnetization processes. This scenario is strongly reinforced by laboratory experiments that show large resistance to thermal demagnetization when thermoremanence was acquired over a long time period. We speculate that in the present situation exsolution was reactivated during in field reheating and yielded formation of new magnetite, yet magnetic domain state rearrangements could also play a role. Initial reheating when the overlying flow took place, albeit moderate (less than 200-300 °C), was enough to produce overlying components with significantly higher unblocking temperatures.

  11. Reverse Genetics Approaches for the Development of Influenza Vaccines

    Science.gov (United States)

    Nogales, Aitor; Martínez-Sobrido, Luis

    2016-01-01

    Influenza viruses cause annual seasonal epidemics and occasional pandemics of human respiratory disease. Influenza virus infections represent a serious public health and economic problem, which are most effectively prevented through vaccination. However, influenza viruses undergo continual antigenic variation, which requires either the annual reformulation of seasonal influenza vaccines or the rapid generation of vaccines against potential pandemic virus strains. The segmented nature of influenza virus allows for the reassortment between two or more viruses within a co-infected cell, and this characteristic has also been harnessed in the laboratory to generate reassortant viruses for their use as either inactivated or live-attenuated influenza vaccines. With the implementation of plasmid-based reverse genetics techniques, it is now possible to engineer recombinant influenza viruses entirely from full-length complementary DNA copies of the viral genome by transfection of susceptible cells. These reverse genetics systems have provided investigators with novel and powerful approaches to answer important questions about the biology of influenza viruses, including the function of viral proteins, their interaction with cellular host factors and the mechanisms of influenza virus transmission and pathogenesis. In addition, reverse genetics techniques have allowed the generation of recombinant influenza viruses, providing a powerful technology to develop both inactivated and live-attenuated influenza vaccines. In this review, we will summarize the current knowledge of state-of-the-art, plasmid-based, influenza reverse genetics approaches and their implementation to provide rapid, convenient, safe and more effective influenza inactivated or live-attenuated vaccines. PMID:28025504

  12. Reverse genetics in ecological research.

    Directory of Open Access Journals (Sweden)

    Jens Schwachtje

    Full Text Available By precisely manipulating the expression of individual genetic elements thought to be important for ecological performance, reverse genetics has the potential to revolutionize plant ecology. However, untested concerns about possible side-effects of the transformation technique, caused by Agrobacterium infection and tissue culture, on plant performance have stymied research by requiring onerous sample sizes. We compare 5 independently transformed Nicotiana attenuata lines harboring empty vector control (EVC T-DNA lacking silencing information with isogenic wild types (WT, and measured a battery of ecologically relevant traits, known to be important in plant-herbivore interactions: phytohormones, secondary metabolites, growth and fitness parameters under stringent competitive conditions, and transcriptional regulation with microarrays. As a positive control, we included a line silenced in trypsin proteinase inhibitor gene (TPI expression, a potent anti-herbivore defense known to exact fitness costs in its expression, in the analysis. The experiment was conducted twice, with 10 and 20 biological replicates per genotype. For all parameters, we detected no difference between any EVC and WT lines, but could readily detect a fitness benefit of silencing TPI production. A statistical power analyses revealed that the minimum sample sizes required for detecting significant fitness differences between EVC and WT was 2-3 orders of magnitude larger than the 10 replicates required to detect a fitness effect of TPI silencing. We conclude that possible side-effects of transformation are far too low to obfuscate the study of ecologically relevant phenotypes.

  13. Reverse Engineering Adverse Outcome Pathways

    Energy Technology Data Exchange (ETDEWEB)

    Perkins, Edward; Chipman, J.K.; Edwards, Stephen; Habib, Tanwir; Falciani, Francesco; Taylor, Ronald C.; Van Aggelen, Graham; Vulpe, Chris; Antczak, Philipp; Loguinov, Alexandre

    2011-01-30

    The toxicological effects of many stressors are mediated through unknown, or poorly characterized, mechanisms of action. We describe the application of reverse engineering complex interaction networks from high dimensional omics data (gene, protein, metabolic, signaling) to characterize adverse outcome pathways (AOPs) for chemicals that disrupt the hypothalamus-pituitary-gonadal endocrine axis in fathead minnows. Gene expression changes in fathead minnow ovaries in response to 7 different chemicals, over different times, doses, and in vivo versus in vitro conditions were captured in a large data set of 868 arrays. We examined potential AOPs of the antiandrogen flutamide using two mutual information theory methods, ARACNE and CLR to infer gene regulatory networks and potential adverse outcome pathways. Representative networks from these studies were used to predict a network path from stressor to adverse outcome as a candidate AOP. The relationship of individual chemicals to an adverse outcome can be determined by following perturbations through the network in response to chemical treatment leading to the nodes associated with the adverse outcome. Identification of candidate pathways allows for formation of testable hypotheses about key biologic processes, biomarkers or alternative endpoints, which could be used to monitor an adverse outcome pathway. Finally, we identify the unique challenges facing the application of this approach in ecotoxicology, and attempt to provide a road map for the utilization of these tools. Key Words: mechanism of action, toxicology, microarray, network inference

  14. Solution to reverse refraction problem

    Science.gov (United States)

    Pavelyev, A. G.

    1985-04-01

    The reverse refraction problem (determination of radial profile of refractive index in planetary atmospheres, such as Earth, from radio probe measurements) is formulated as a bistatic radar problem for a spherically symmetric medium. The modified refractive index n(r)r (a-radius at which the refraction angle as function of relative distance is measured) is assumed to reach extreme values at the upper boundary r sub 1 or at observation level. Before the corresponding Fredholm equation of the first kind can be solved, it must be well-conditioned in the Tikhonov sense. This is done here by two quasi-optimum integral transformation variants with respect to the measurement function and subsequent simplified regularization. The first method is two successive Fourier cosine transformations followed by an Abel transformation, with the possibility of discrete Fourier transformations and numerical Abel transformation. The second method is twofold discrete Fourier transformation. Both yield solutions readily evaluated by simple algorithms. Regularization is effected by approximating functions satisfying the two fundamental conditions for convergence required of the measurement function.

  15. Micromagnetic study of magnetic domain structure and magnetization reversal in amorphous wires with circular anisotropy

    Energy Technology Data Exchange (ETDEWEB)

    Betancourt, I., E-mail: israelb@correo.unam.m [Departamento de Materiales Metalicos y Ceramicos, Instituto de Investigaciones en Materiales, Universidad Nacional Autonoma de Mexico, Mexico D.F. 04510 (Mexico); Hrkac, G. [Department of Engineering Materials, University of Sheffield, Mappin St., Sheffield S1 3JD (United Kingdom); Schrefl, T. [Department of Engineering Materials, University of Sheffield, Mappin St., Sheffield S1 3JD (United Kingdom); St. Poelten University of Applied Sciences (Austria)

    2011-05-15

    In this work we present a detailed numerical investigation on the magnetic domain formation and magnetization reversal mechanism in sub-millimeter amorphous wires with negative magnetostriction by means of micromagnetic calculations. The formation of circular magnetic domains surrounding a multidomain axially oriented central nucleus was observed for the micromagnetic model representing the amorphous wire. The magnetization reversal explained by micromagnetic computations for the M-H curve is described in terms of a combined nucleation-propagation-rotational mechanism after the saturated state. Results are interpreted in terms of the effective magnetic anisotropy. - Research highlights: > Magnetic domain formation in small amorphous wires is studied by micromagnetic calculations. > Magnetization reversal in small amorphous wires is studied by micromagnetic calculations. > Formation of circular domains around an axially oriented central core was observed. > Magnetization reversal is described in terms of nucleation-propagation-rotational mechanisms. > Magnetic domains and reversal mechanism are consistent with experimental reports.

  16. Time-reversal-breaking induced quantum spin Hall effect

    Science.gov (United States)

    Luo, Wei; Shao, D. X.; Deng, Ming-Xun; Deng, W. Y.; Sheng, L.

    2017-01-01

    We show that quantum spin Hall (QSH) effect does not occur in a square lattice model due to cancellation of the intrinsic spin-orbit coupling coming from different hopping paths. However, we show that QSH effect can be induced by the presence of staggered magnetic fluxes alternating directions square by square. When the resulting Peierls phase takes a special value , the system has a composite symmetry ΘΡ− with Θ the time-reversal operator and Ρ− transforming the Peierls phase from γ to γ − , which protects the gapless edge states. Once the phase deviates from , the edge states open a gap, as the composite symmetry is broken. We further investigate the effect of a Zeeman field on the QSH state, and find that the edge states remain gapless for . This indicates that the QSH effect is immune to the magnetic perturbation. PMID:28220858

  17. Fluctuations in 2D reversibly-damped turbulence

    CERN Document Server

    Rondoni, L; Rondoni, Lamberto; Segre, Enrico

    1998-01-01

    G. Gallavotti has recently proposed an equivalence principle, in hydrodynamics, which states that the properties of forced-damped fluids can be equally well represented by means of the Navier-Stokes equations and by means of special time reversible dynamical systems called GNS. In the GNS systems, the ordinary, irreversible, dissipation is replaced by a state-dependent dissipation which fixes one global quantity. The principle then states that the mean values of properly chosen observables should be the same for both representations of the fluid. In the same paper, the chaotic hypothesis of Gallavotti and Cohen is extended to hydrodynamics, leading to the conjecture that entropy fluctuations in the GNS system should verify a relation first observed in nonequilibrium molecular dynamics. We tested these ideas in the case of two-dimensional incompressible fluids. We examined the fluctuations of global quantities, such as the energy and the enstrophy, in the statistically stationary state of a) the Navier-Stokes ...

  18. Reversible temperature exchange upon thermal contact

    Science.gov (United States)

    Mishchenko, Eugene G.; Pshenichka, Paul F.

    2017-01-01

    According to a well-known principle of thermodynamics, the transfer of heat between two bodies is reversible when their temperatures are infinitesimally close. As we demonstrate, a little-known alternative exists: two bodies with temperatures different by an arbitrary amount can completely exchange their temperatures in a reversible way if split into infinitesimal parts that are brought into thermal contact sequentially.

  19. Magnetic reversals from planetary dynamo waves.

    Science.gov (United States)

    Sheyko, Andrey; Finlay, Christopher C; Jackson, Andrew

    2016-11-24

    A striking feature of many natural dynamos is their ability to undergo polarity reversals. The best documented example is Earth's magnetic field, which has reversed hundreds of times during its history. The origin of geomagnetic polarity reversals lies in a magnetohydrodynamic process that takes place in Earth's core, but the precise mechanism is debated. The majority of numerical geodynamo simulations that exhibit reversals operate in a regime in which the viscosity of the fluid remains important, and in which the dynamo mechanism primarily involves stretching and twisting of field lines by columnar convection. Here we present an example of another class of reversing-geodynamo model, which operates in a regime of comparatively low viscosity and high magnetic diffusivity. This class does not fit into the paradigm of reversal regimes that are dictated by the value of the local Rossby number (the ratio of advection to Coriolis force). Instead, stretching of the magnetic field by a strong shear in the east-west flow near the imaginary cylinder just touching the inner core and parallel to the axis of rotation is crucial to the reversal mechanism in our models, which involves a process akin to kinematic dynamo waves. Because our results are relevant in a regime of low viscosity and high magnetic diffusivity, and with geophysically appropriate boundary conditions, this form of dynamo wave may also be involved in geomagnetic reversals.

  20. Online Reverse Auctions for Procurement of Services

    NARCIS (Netherlands)

    U.L. Radkevitch (Uladzimir)

    2008-01-01

    textabstractOnline reverse auctions, in which a buyer seeks to select a supplier and suppliers compete for contracts by bidding online, revolutionized corporate procurement early this century. Shortly after they had been pioneered by General Electric, many companies rushed to adopt reverse auctions