Science.gov

Sample records for gamma ray-induced reciprocal

  1. The identification of gamma ray induced EAS

    NASA Technical Reports Server (NTRS)

    Blake, P. R.; Nash, W. F.

    1985-01-01

    Some of the penetrating particles in gamma-induced EAS from Cygnus X-3 observed by a single layer of flash-bulbs under 880 g cm/2 concrete, may be punched through photons rather than muons. An analysis of the shielded flash-tube response detected from EAS is presented. The penetration of the electro-magnetic component through 20 cm of Pb is observed at core distances approx. 10 m.

  2. Gamma-ray induced displacement in D20 reactors

    SciTech Connect

    Baumann, N.P.

    1990-05-01

    Gamma-ray damage to tank walls is typically more severe in D{sub 2}O than in H{sub 2}O moderated lattices because of the much higher ratios of slow-to-fast neutron flux. To estimate this effect it was first necessary to develop energy dependent gamma-ray displacement cross sections for iron. These, along with coupled neutron-gamma-ray transport computations, provided a measure of displacement damage from this source in SRS reactor tank walls. Gamma-ray displacements originating from high energy gammas from neutron capture in and near the tank wall exceeded those from gamma rays created in the reactor core. The displacements from the combined gamma sources ranged from 13% to 16% of that due to iron atom recoil following neutron capture. 8 refs., 2 figs., 2 tabs.

  3. Process for gamma ray induced degradation of polychlorinated biphenyls

    DOEpatents

    Meikrantz, D.H.; Mincher, B.J.; Arbon, R.E.

    1998-08-25

    The invention is a process for the in-situ destruction of polychlorinated biphenyl (PCB) compounds in transformer oils and transformers. These compounds are broken down selectively by irradiation of the object or mixture using spent nuclear fuel or any isotopic source of high energy gamma radiation. For example, the level of applied dose required to decompose 400 ppm of polychlorinated biphenyl in transformer oil to less than 50 ppm is 500 kilograms. Destruction of polychlorinated biphenyls to levels of less than 50 ppm renders the transformer oil or transformer non-PCB contaminated under current regulations. Therefore, this process can be used to treat PCB contaminated oil and equipment to minimize or eliminate the generation of PCB hazardous waste. 5 figs.

  4. Process for gamma ray induced degradation of polychlorinated biphenyls

    DOEpatents

    Meikrantz, David H.; Mincher, Bruce J.; Arbon, Rodney E.

    1998-01-01

    The invention is a process for the in-situ destruction of polychlorinated biphenyl (PCB) compounds in transformer oils and transformers. These compounds are broken down selectively by irradiation of the object or mixture using spent nuclear fuel or any isotopic source of high energy gamma radiation. For example, the level of applied dose required to decompose 400 ppm of polychlorinated biphenyl in transformer oil to less than 50 ppm is 500 kilogray. Destruction of polychlorinated biphenyls to levels of less than 50 ppm renders the transformer oil or transformer non-PCB contaminated under current regulations. Therefore, this process can be used to treat PCB contaminated oil and equipment to minimize or eliminate the generation of PCB hazardous waste.

  5. Lymphocytes from wasted mice express enhanced spontaneous and {gamma}-ray-induced apoptosis

    SciTech Connect

    Woloschak, G.E. |; Chang-Liu, Chin-Mei; Chung, Jen; Libertin, C.R.

    1993-09-01

    Mice bearing the autosomal recessive mutation wasted (wst/wst) display a disease pattern including faulty repair of DNA damage in lymphocytes after radiation exposure, neurologic abnormalities, and immunodeficiency. Many of the features of this mouse model have suggested a premature or increased spontaneous frequency of apoptosis in thymocytes; past work has shown an inability to establish cultured T cell lines, an abnormally high death rate of stimulated T cells in culture, and an increased sensitivity of T cells to the killing effects of ionizing radiations in wst/wst mice relative to controls. The experiments reported here were designed to examine splenic and thymic lymphocytes from wasted and control mice for signs of early apoptosis. Our results revealed enhanced expression of Rp-8 mRNA (associated with apoptosis) in thymic lymphocytes and reduced expression in splenic lymphocytes of wst/wst mice relative to controls; expression of Rp-2 and Td-30 mRNA (induced during apoptosis) were not detectable in spleen or thymus. Higher spontaneous DNA fragmentation was observed in wasted mice than in controls; however, {gamma}-ray-induced DNA fragmentation peaked at a lower dose and occurred to a greater extent in wasted mice relative to controls. These results provide evidence for high spontaneous and {gamma}-ray-induced apoptosis in T cells of wasted mice as a mechanism underlying the observed lymphocyte and DNA repair abnormalities.

  6. Clonally Expanding Thymocytes Having Lineage Capability in Gamma-Ray-Induced Mouse Atrophic Thymus

    SciTech Connect

    Yamamoto, Takashi; Morita, Shin-ichi; Go, Rieka; Obata, Miki; Katsuragi, Yoshinori; Fujita, Yukari; Maeda, Yoshitaka; Yokoyama, Minesuke; Aoyagi, Yutaka; Ichikawa, Hitoshi; Mishima, Yukio; Kominami, Ryo

    2010-05-01

    Purpose: To characterize, in the setting of gamma-ray-induced atrophic thymus, probable prelymphoma cells showing clonal growth and changes in signaling, including DNA damage checkpoint. Methods and Materials: A total of 111 and 45 mouse atrophic thymuses at 40 and 80 days, respectively, after gamma-irradiation were analyzed with polymerase chain reaction for D-J rearrangements at the TCRbeta locus, flow cytometry for cell cycle, and Western blotting for the activation of DNA damage checkpoints. Results: Limited D-J rearrangement patterns distinct from normal thymus were detected at high frequencies (43 of 111 for 40-day thymus and 21 of 45 for 80-day thymus). Those clonally expanded thymocytes mostly consisted of CD4{sup +}CD8{sup +} double-positive cells, indicating the retention of lineage capability. They exhibited pausing at a late G1 phase of cell cycle progression but did not show the activation of DNA damage checkpoints such as gammaH2AX, Chk1/2, or p53. Of interest is that 17 of the 52 thymuses showing normal D-J rearrangement patterns at 40 days after irradiation showed allelic loss at the Bcl11b tumor suppressor locus, also indicating clonal expansion. Conclusion: The thymocytes of clonal growth detected resemble human chronic myeloid leukemia in possessing self-renewal and lineage capability, and therefore they can be a candidate of the lymphoma-initiating cells.

  7. The measurement of gamma ray induced heating in a mixed neutron and gamma ray environment

    SciTech Connect

    Chiu, H.K.

    1991-10-01

    The problem of measuring the gamma heating in a mixed DT neutron and gamma ray environment was explored. A new detector technique was developed to make this measurement. Gamma heating measurements were made in a low-Z assembly irradiated with 14-Mev neutrons and (n, n{prime}) gammas produced by a Texas Nuclear Model 9400 neutron generator. Heating measurements were made in the mid-line of the lattice using a proportional counter operating in the Continuously-varied Bias-voltage Acquisition mode. The neutron-induced signal was separated from the gamma-induced signal by exploiting the signal rise-time differences inherent to radiations of different linear energy transfer coefficient, which are observable in a proportional counter. The operating limits of this measurement technique were explored by varying the counter position in the low-Z lattice, hence changing the irradiation spectrum observed. The experiment was modelled numerically to help interpret the measured results. The transport of neutrons and gamma rays in the assembly was modelled using the one- dimensional radiation transport code ANISN/PC. The cross-section set used for these calculations was derived from the ENDF/B-V library using the code MC{sup 2}-2 for the case of DT neutrons slowing down in a low-Z material. The calculated neutron and gamma spectra in the slab and the relevant mass-stopping powers were used to construct weighting factors which relate the energy deposition in the counter fill-gas to that in the counter wall and in the surrounding material. The gamma energy deposition at various positions in the lattice is estimated by applying these weighting factors to the measured gamma energy deposition in the counter at those locations.

  8. Evaluation of the cosmic-ray induced background in coded aperture high energy gamma-ray telescopes

    NASA Technical Reports Server (NTRS)

    Owens, Alan; Barbier, Loius M.; Frye, Glenn M.; Jenkins, Thomas L.

    1991-01-01

    While the application of coded-aperture techniques to high-energy gamma-ray astronomy offers potential arc-second angular resolution, concerns were raised about the level of secondary radiation produced in a thick high-z mask. A series of Monte-Carlo calculations are conducted to evaluate and quantify the cosmic-ray induced neutral particle background produced in a coded-aperture mask. It is shown that this component may be neglected, being at least a factor of 50 lower in intensity than the cosmic diffuse gamma-rays.

  9. Fermi large area telescope observations of the cosmic-ray induced {gamma}-ray emission of the Earth's atmosphere

    SciTech Connect

    Abdo, A. A.; Ackermann, M.; Ajello, M.; Bechtol, K.; Berenji, B.; Bloom, E. D.; Borgland, A. W.; Bouvier, A.; Buehler, R.; Cameron, R. A.; Charles, E.; Chiang, J.; Claus, R.; Digel, S. W.; Couto e Silva, E. do; Drell, P. S.; Dubois, R.; Focke, W. B.; Funk, S.; Glanzman, T.

    2009-12-15

    We report on measurements of the cosmic-ray induced {gamma}-ray emission of Earth's atmosphere by the Large Area Telescope on board the Fermi Gamma-ray Space Telescope. The Large Area Telescope has observed the Earth during its commissioning phase and with a dedicated Earth limb following observation in September 2008. These measurements yielded {approx}6.4x10{sup 6} photons with energies >100 MeV and {approx}250 hours total live time for the highest quality data selection. This allows the study of the spatial and spectral distributions of these photons with unprecedented detail. The spectrum of the emission--often referred to as Earth albedo gamma-ray emission--has a power-law shape up to 500 GeV with spectral index {gamma}=2.79{+-}0.06.

  10. Cosmic-ray induced gamma-ray emission from the starburst galaxy NGC 253

    SciTech Connect

    Wang, Xilu; Fields, Brian D.

    2014-05-09

    Cosmic rays in galaxies interact with the interstellar medium and give us a direct view of nuclear and particle interactions in the cosmos. For example, cosmic-ray proton interactions with interstellar hydrogen produce gamma rays via PcrPism→π{sup 0}→γγ. For a 'normal' star-forming galaxy like the Milky Way, most cosmic rays escape the Galaxy before such collisions, but in starburst galaxies with dense gas and huge star formation rate, most cosmic rays do suffer these interactions [1,2]. We construct a 'thick-target' model for starburst galaxies, in which cosmic rays are accelerated by supernovae, and escape is neglected. This model gives an upper limit to the gamma-ray emission. Only two free parameters are involved in the model: cosmic-ray proton acceleration energy rate from supernova and the proton injection spectral index. The pionic gamma-radiation is calculated from 10 MeV to 10 TeV for the starburst galaxy NGC 253, and compared to Fermi and HESS data. Our model fits NGC 253 well, suggesting that cosmic rays in this starburst are in the thick target limit, and that this galaxy is a gamma-ray calorimeter.

  11. Thermal and Gamma-ray induced relaxation in As-S glasses: modeling and experiment

    SciTech Connect

    Lucas, Pierre; King, Ellyn A.; Erdmann, Robert G.; Riley, Brian J.; Sundaram, S. K.; McCloy, John S.

    2011-09-09

    Enthalpy relaxation is measured in a series of As-S glasses irradiated with gamma rays and these samples are compared with a set of identical control samples kept in the dark. It is shown that gamma irradiation lifts the kinetic barrier for relaxation at room temperature and speeds up the enthalpy release. The measured values of thermal relaxation in the dark agree closely with modeling results obtained by fitting differential scanning calorimetry curves with the TNM equations. The measured values of activation energy for enthalpy relaxation are also in close agreement with that predicted by the TNM model therefore lending credence to the fitting results. These measurements permit extraction of the effect of gamma irradiation on the glass structure for a series of As-S glasses with increasing structural coordination, and gamma irradiation is shown to reduce the structural relaxation time. It is also shown that lower coordination glasses exhibit greater radiation sensitivity but also greater thermal relaxation due to their lower Tg. On the other end, over-coordinated glasses show lower relaxation and almost no radiation sensitivity. This behavior is similar to the glass response under sub-bandgap light irradiation.

  12. Cosmic-ray induced gamma-ray emission from the starburst galaxy NGC 253

    NASA Astrophysics Data System (ADS)

    Wang, Xilu; Fields, Brian D.

    2014-05-01

    Cosmic rays in galaxies interact with the interstellar medium and give us a direct view of nuclear and particle interactions in the cosmos. For example, cosmic-ray proton interactions with interstellar hydrogen produce gamma rays via PcrPism→π0→γγ. For a "normal" star-forming galaxy like the Milky Way, most cosmic rays escape the Galaxy before such collisions, but in starburst galaxies with dense gas and huge star formation rate, most cosmic rays do suffer these interactions [1,2]. We construct a "thick-target" model for starburst galaxies, in which cosmic rays are accelerated by supernovae, and escape is neglected. This model gives an upper limit to the gamma-ray emission. Only two free parameters are involved in the model: cosmic-ray proton acceleration energy rate from supernova and the proton injection spectral index. The pionic gamma-radiation is calculated from 10 MeV to 10 TeV for the starburst galaxy NGC 253, and compared to Fermi and HESS data. Our model fits NGC 253 well, suggesting that cosmic rays in this starburst are in the thick target limit, and that this galaxy is a gamma-ray calorimeter.

  13. Search for Cosmic-Ray-Induced Gamma-Ray Emission in Galaxy Clusters

    NASA Technical Reports Server (NTRS)

    Ackermann, M.; Ajello, M.; Albert, A.; Allafort, A.; Atwood, W. B.; Baldini, L.; Ballet, J.; Barbiellini, G.; Bastieri, D.; Bechtol, K.; Bellazzini, R.; Bloom, E. D.; Bonamente, E.; Bottacini, E.; Brandt, T. J.; Bregeon, J.; Brigida, M.; Bruel, P.; Buehler, R.; Buson, S.; Caliandro, G. A.; Cameron, R. A.; Caraveo, P. A.; Cavazzuti, E.; Chaves, R. C. G.; Kuss, M.; Pesce-Rollins, M.; Sgro, C.; Spandre, G.; Tinivella, M.

    2014-01-01

    Current theories predict relativistic hadronic particle populations in clusters of galaxies in addition to the already observed relativistic leptons. In these scenarios hadronic interactions give rise to neutral pions which decay into gamma rays that are potentially observable with the Large Area Telescope (LAT) on board the Fermi space telescope. We present a joint likelihood analysis searching for spatially extended gamma-ray emission at the locations of 50 galaxy clusters in four years of Fermi-LAT data under the assumption of the universal cosmic-ray (CR) model proposed by Pinzke & Pfrommer. We find an excess at a significance of 2.7 delta, which upon closer inspection, however, is correlated to individual excess emission toward three galaxy clusters: A400, A1367, and A3112. We discuss these cases in detail and conservatively attribute the emission to unmodeled background systems (for example, radio galaxies within the clusters).Through the combined analysis of 50 clusters, we exclude hadronic injection efficiencies in simple hadronic models above 21% and establish limits on the CR to thermal pressure ratio within the virial radius, R(sub 200), to be below 1.25%-1.4% depending on the morphological classification. In addition, we derive new limits on the gamma-ray flux from individual clusters in our sample.

  14. Gamma-ray induced degradation of diazinon and atrazine in natural groundwaters.

    PubMed

    Mohamed, K A; Basfar, A A; Al-Shahrani, A A

    2009-07-30

    Degradation of diazinon and atrazine pesticides present in natural groundwaters was investigated on a laboratory scale upon gamma-irradiation from a (60)Co source. The effects of pesticide type, initial concentration, characteristics of natural groundwater, potential radical scavengers and absorbed dose on efficiency of pesticide degradation were investigated using GC-MS. gamma-Irradiation experiments were carried out for three concentrations (i.e. 0.329, 1.643 and 3.286 microM/diazinon and 0.464, 2.318 and 4.636 microM/atrazine) with irradiation doses over the range 0.5-5.6 kGy for diazinon and 0.2-21 kGy for atrazine. gamma-Radiolysis showed that diazinon was much easier to degrade by ionizing radiation compared to atrazine in all natural groundwater samples. This was observed at the three initial concentrations over the range irradiation doses. The irradiation doses required for degradation of 50 and 90% diazinon (distilled water) and atrazine (humic aqueous solution) at the three concentrations were not sufficient to degrade the same concentrations in different natural groundwater samples. Moreover, the presence of naturally occurring inorganic scavengers in solutions of diazinon and atrazine decreased significantly the efficiency of radiolytic degradation of pesticides, especially at higher concentrations.

  15. Assessment of gamma ray-induced DNA damage in Lasioderma serricorne using the comet assay

    NASA Astrophysics Data System (ADS)

    Kameya, Hiromi; Miyanoshita, Akihiro; Imamura, Taro; Todoriki, Setsuko

    2012-03-01

    We attempted a DNA comet assay under alkaline conditions to verify the irradiation treatment of pests. Lasioderma serricorne (Fabricius) were chosen as test insects and irradiated with gamma rays from a 60Co source at 1 kGy. We conducted the comet assay immediately after irradiation and over time for 7 day. Severe DNA fragmentation in L. serricorne cells was observed just after irradiation and the damage was repaired during the post-irradiation period in a time-dependent manner. The parameters of the comet image analysis were calculated, and the degree of DNA damage and repair were evaluated. Values for the Ratio (a percentage determined by fluorescence in the damaged area to overall luminance, including intact DNA and the damaged area of a comet image) of individual cells showed that no cells in the irradiated group were included in the Ratio<0.1 category, the lowest grade. This finding was observed consistently throughout the 7-day post-irradiation period. We suggest that the Ratio values of individual cells can be used as an index of irradiation history and conclude that the DNA comet assay under alkaline conditions, combined with comet image analysis, can be used to identify irradiation history.

  16. Gamma rays induce DNA damage and oxidative stress associated with impaired growth and reproduction in the copepod Tigriopus japonicus.

    PubMed

    Han, Jeonghoon; Won, Eun-Ji; Lee, Bo-Young; Hwang, Un-Ki; Kim, Il-Chan; Yim, Joung Han; Leung, Kenneth Mei Yee; Lee, Yong Sung; Lee, Jae-Seong

    2014-07-01

    Nuclear radioisotope accidents are potentially ecologically devastating due to their impact on marine organisms. To examine the effects of exposure of a marine organism to radioisotopes, we irradiated the intertidal copepod Tigriopus japonicus with several doses of gamma radiation and analyzed the effects on mortality, fecundity, and molting by assessing antioxidant enzyme activities and gene expression patterns. No mortality was observed at 96h, even in response to exposure to a high dose (800Gy) of radiation, but mortality rate was significantly increased 120h (5 days) after exposure to 600 or 800Gy gamma ray radiation. We observed a dose-dependent reduction in fecundity of ovigerous females; even the group irradiated with 50Gy showed a significant reduction in fecundity, suggesting that gamma rays are likely to have a population level effect. In addition, we observed growth retardation, particularly at the nauplius stage, in individuals after gamma irradiation. In fact, nauplii irradiated with more than 200Gy, though able to molt to copepodite stage 1, did not develop into adults. Upon gamma radiation, T. japonicus showed a dose-dependent increase in reactive oxygen species (ROS) levels, the activities of several antioxidant enzymes, and expression of double-stranded DNA break damage genes (e.g. DNA-PK, Ku70, Ku80). At a low level (sub-lethal dose) of gamma irradiation, we found dose-dependent upregulation of p53, implying cellular damage in T. japonicus in response to sub-lethal doses of gamma irradiation, suggesting that T. japonicus is not susceptible to sub-lethal doses of gamma irradiation. Additionally, antioxidant genes, phase II enzyme (e.g. GSTs), and cellular chaperone genes (e.g. Hsps) that are involved in cellular defense mechanisms also showed the same expression patterns for sublethal doses of gamma irradiation (50-200Gy). These findings indicate that sublethal doses of gamma radiation can induce oxidative stress-mediated DNA damage and increase

  17. Repeated doses of gamma rays induce resistance to N-methyl-N'-nitro-N-nitrosoguanidine in Chinese hamster cells

    SciTech Connect

    Osmak, M.

    1988-09-01

    Chinese hamster V79 cells were preirradiated repeatedly with gamma rays and then exposed to ultraviolet (uv) light or N-methyl-N'-nitro-N-nitrosoguanidine (MNNG). The cell killing and induction of mutation at the hypoxanthine-guanine phosphoribosyltransferase locus were examined following these treatments. Cells preirradiated with multiple fractions of gamma rays exhibit the same sensitivity to uv light as the control cells with respect to cell survival and mutation induction. Following treatment with MNNG, resistance to cell killing was observed along with a decreased frequency of mutations induced. These results indicate that the progeny of cells irradiated with multiple fractions of gamma rays could display subsequent changes in sensitivity to lethal and mutagenic effects of additional treatment with DNA-damaging agents.

  18. Effect of vitamin-antioxidant micronutrients on the frequency of spontaneous and in vitro gamma-ray-induced micronuclei in lymphocytes of donors: the age factor.

    PubMed

    Gaziev, A I; Sologub, G R; Fomenko, L A; Zaichkina, S I; Kosyakova, N I; Bradbury, R J

    1996-03-01

    The effect of prolonged consumption of a vitamin-antioxidant mixture (VAM) on the frequency of spontaneous and in vitro gamma-radiation-induced micronuclei (MN) in peripheral blood lymphocytes in donors of various ages was investigated. Three groups of donors were recruited: (i) 56-83 years old (35 subjects), (ii) 23-30 years old (13 subjects), and (iii) 63-82 years old (12 subjects). Blood was sampled every 4 months for one year in all donors of the three groups. After the first sampling of blood, the donors of groups (i) and (ii) took VAM containing the vitamins A, C, E, as well as beta-carotene, folic acid, and rutin daily for 4 months. After the second blood sampling, the intake of VAM was terminated. The third blood sample was taken 4 months after termination of VAM intake. A part of the blood was exposed to gamma-radiation and the frequency of spontaneous and induced MN in lymphocytes was assayed. The analyses showed that the frequency of spontaneous and in vitro gamma-ray-induced MN in aged donors was significantly higher than that in young donors. No seasonal variations in MN frequency were observed in human lymphocytes during one year. Aged donors showed a statistically significant decrease in spontaneous MN in lymphocytes after a 4 month period of consumption of VAM. The intake of VAM by both aged and young donors promoted a decrease in MN induced lymphocytes in vitro by gamma-radiation. The results of our observations enable the suggestion that consumption of VAM favours a decrease in the chromosome damage produced by endogenous and exogenous factors in human lymphocytes.

  19. Variation in sensitivity to. gamma. -ray-induced chromosomal aberrations during the mitotic cycle of the sea urchin egg

    SciTech Connect

    Ejima, Y.; Nakamura, I.; Shiroya, T.

    1982-11-01

    Sea urchin eggs were irradiated with /sup 137/Cs ..gamma.. rays at various stages of the mitotic cycle, and chromosomal aberrations at the first postirradiation mitosis and embryonic abnormalities at later developmental stages were examined. The radiosensitivity of the eggs to both endpoints varied in parallel with the mitotic stage at the time of irradiation, suggesting a possible relationship between chromosomal damage and embryonic abnormalities.

  20. Age-related increase in the rate of spontaneou and {gamma}-ray-induced hprt mutations in mouse spleen lymphocytes

    SciTech Connect

    Gazlev, A.I.; Podlutskii, A.Ya.; Bradbury, R.

    1994-11-01

    Endogenous and exogenous factors continually afflict DNA of cells of organisms. A certain amount of the damage is accumulated causing mutations, increasing the risk of malignacies, impairing cell functions, and upsetting the body`s homeostasis. The research reported here studies the rates of spontaneous hprt nmutationsand those induced you ggammairradiation in the splenocytes of mice at various ages. The rate of spontaneous and induced hprt gene mutations increases with aging. In gamma irradiated mice the rate of radiation-induced mutations depended on the absorbed dose and age, with the rate 2.3-3.0 fold higher in 104-110 week old mice than in younger pups. 15 refs., 1 tab.

  1. Gamma ray-induced synthesis of hyaluronic acid/chondroitin sulfate-based hydrogels for biomedical applications

    NASA Astrophysics Data System (ADS)

    Zhao, Linlin; Gwon, Hui-Jeong; Lim, Youn-Mook; Nho, Young-Chang; Kim, So Yeon

    2015-01-01

    Hyaluronic acid (HA)/chondroitin sulfate (CS)/poly(acrylic acid) (PAAc) hydrogel systems were synthesized by gamma-ray irradiation without the use of additional initiators or crosslinking agents to achieve a biocompatible hydrogel system for skin tissue engineering. HA and CS derivatives with polymerizable residues were synthesized. Then, the hydrogels composed of glycosaminoglycans, HA, CS, and a synthetic ionic polymer, PAAc, were prepared using gamma-ray irradiation through simultaneous free radical copolymerization and crosslinking. The physicochemical properties of the HA/CS/PAAc hydrogels having various compositions were investigated to evaluate their feasibility as artificial skin substitutes. The gel fractions of the HA/CS/PAAc hydrogels increased in absorbed doses up to 15 kGy, and they exhibited 91-93% gel fractions under 15 kGy radiation. All of the HA/CS/PAAc hydrogels exhibited relatively high water contents of over 90% and reached an equilibrium swelling state within 24 h. The enzymatic degradation kinetics of the HA/CS/PAAc hydrogels depended on both the concentration of the hyaluronidase solution and the ratio of HA/CS/PAAc. The in vitro drug release profiles of the HA/CS/PAAc hydrogels were significantly influenced by the interaction between the ionic groups in the hydrogels and the ionic drug molecules as well as the swelling of the hydrogels. From the cytotoxicity results of human keratinocyte (HaCaT) cells cultured with extracts of the HA/CS/PAAc hydrogels, all of the HA/CS/PAAc hydrogel samples tested showed relatively high cell viabilities of more than 82%, and did not induce any significant adverse effects on cell viability.

  2. Estrogens decrease {gamma}-ray-induced senescence and maintain cell cycle progression in breast cancer cells independently of p53

    SciTech Connect

    Toillon, Robert-Alain . E-mail: robert.toillon@univ-lille1.fr; Magne, Nicolas; Laios, Ioanna; Castadot, Pierre; Kinnaert, Eric; Van Houtte, Paul; Desmedt, Christine B.Sc.; Leclercq, Guy; Lacroix, Marc

    2007-03-15

    Purpose: Sequential administration of radiotherapy and endocrine therapy is considered to be a standard adjuvant treatment of breast cancer. Recent clinical reports suggest that radiotherapy could be more efficient in association with endocrine therapy. The aim of this study was to evaluate the estrogen effects on irradiated breast cancer cells (IR-cells). Methods and Materials: Using functional genomic analysis, we examined the effects of 17-{beta}-estradiol (E{sub 2}, a natural estrogen) on MCF-7 breast cancer cells. Results: Our results showed that E{sub 2} sustained the growth of IR-cells. Specifically, estrogens prevented cell cycle blockade induced by {gamma}-rays, and no modification of apoptotic rate was detected. In IR-cells we observed the induction of genes involved in premature senescence and cell cycle progression and investigated the effects of E{sub 2} on the p53/p21{sup waf1/cip1}/Rb pathways. We found that E{sub 2} did not affect p53 activation but it decreased cyclin E binding to p21{sup waf1/cip1} and sustained downstream Rb hyperphosphorylation by functional inactivation of p21{sup waf1/cip1}. We suggest that Rb inactivation could decrease senescence and allow cell cycle progression in IR-cells. Conclusion: These results may help to elucidate the molecular mechanism underlying the maintenance of breast cancer cell growth by E{sub 2} after irradiation-induced damage. They also offer clinicians a rational basis for the sequential administration of ionizing radiation and endocrine therapies.

  3. Gamma ray induced DNA damage in human and mouse leucocytes measured by SCGE-Pro: a software developed for automated image analysis and data processing for Comet assay.

    PubMed

    Chaubey, R C; Bhilwade, H N; Rajagopalan, R; Bannur, S V

    2001-02-20

    The studies reported in this communication had two major objectives: first to validate the in-house developed SCGE-Pro: a software developed for automated image analysis and data processing for Comet assay using human peripheral blood leucocytes exposed to radiation doses, viz. 2, 4 and 8 Gy, which are known to produce DNA/chromosome damage using alkaline Comet assay. The second objective was to investigate the effect of gamma radiation on DNA damage in mouse peripheral blood leucocytes using identical doses and experimental conditions, e.g. lyses, electrophoretic conditions and duration of electrophoresis which are known to affect tail moment (TM) and tail length (TL) of comets. Human and mouse whole blood samples were irradiated with different doses of gamma rays, e.g. 2, 4 and 8 Gy at a dose rate of 0.668Gy/min between 0 and 4 degrees C in air. After lyses, cells were electrophorased under alkaline conditions at pH 13, washed and stained with propidium iodide. Images of the cells were acquired and analyzed using in-house developed imaging software, SCGE-Pro, for Comet assay. For each comet, total fluorescence, tail fluorescence and tail length were measured. Increase in TM and TL was considered as the criteria of DNA damage. Analysis of data revealed heterogeneity in the response of leucocytes to gamma ray induced DNA damage both in human as well as in mouse. A wide variation in TM and TL was observed in control and irradiated groups of all the three donors. Data were analyzed for statistical significance using one-way ANOVA. Though a small variation in basal level of TM and TL was observed amongst human and mouse controls, the differences were not statistically significant. A dose-dependent increase in TM (P<0.001) and TL (P<0.001) was obtained at all the radiation doses (2-8 Gy) both in human and mouse leucocytes. However, there was a difference in the nature of dose response curves for human and mouse leucocytes. In human leucocytes, a linear increase in TM

  4. Plutonium gamma-ray measurements for mutual reciprocal inspections of dismantled nuclear weapons

    SciTech Connect

    Koenig, Z.M.; Carlson, J.B.; Clark, D.; Gosnell, T.B.

    1995-07-01

    The O`Leary-Mikhailov agreement of March 1994 stated that the U.S. and the Russian Federation would engage in mutual reciprocal inspections (MRI) of fissile materials removed from dismantled nuclear weapons. It was decided to begin with the plutonium (Pu) removed from dismantled weapons and held in storage containers. Later discussions between U.S. and Russian technical experts led to the conclusion that, to achieve the O`Leary-Mikhailov objectives, Pu MRI would need to determine that the material in the containers has properties consistent with a nuclear-weapon component. Such a property is a {sup 240}Pu/{sup 239}Pu ratio consistent with weapons-grade material. One of the candidate inspection techniques under consideration for Pu MRI is to use a narrow region (630-670 keV) of the plutonium gamma-ray spectrum, taken with a high-purity germanium detector, to determine that it is weapons-grade plutonium as well as to estimate the minimum mass necessary to produce the observed gamma-ray intensity. We developed software (the Pu600 code) for instrument control and analysis especially for this purpose. In November 1994, U.S. and Russian scientists met at the Lawrence Livermore National Laboratory for joint experiments to evaluate candidate Pu MRI inspection techniques. In one of these experiments, gamma-ray intensities were measured from three unclassified weapons-grade plutonium source standards and one reactor-grade standard (21% {sup 240}pu). Using our software, we determined the {sup 240}Pu/{sup 239}Pu ratio of these standards to accuracies within {+-}10%, which is adequate for Pu MRI. The minimum mass estimates varied, as expected, directly with the exposed surface area of the standards.

  5. The cAMP signaling system inhibits the repair of {gamma}-ray-induced DNA damage by promoting Epac1-mediated proteasomal degradation of XRCC1 protein in human lung cancer cells

    SciTech Connect

    Cho, Eun-Ah; Juhnn, Yong-Sung

    2012-06-01

    Highlights: Black-Right-Pointing-Pointer cAMP signaling system inhibits repair of {gamma}-ray-induced DNA damage. Black-Right-Pointing-Pointer cAMP signaling system inhibits DNA damage repair by decreasing XRCC1 expression. Black-Right-Pointing-Pointer cAMP signaling system decreases XRCC1 expression by promoting its proteasomal degradation. Black-Right-Pointing-Pointer The promotion of XRCC1 degradation by cAMP signaling system is mediated by Epac1. -- Abstract: Cyclic AMP is involved in the regulation of metabolism, gene expression, cellular growth and proliferation. Recently, the cAMP signaling system was found to modulate DNA-damaging agent-induced apoptosis by regulating the expression of Bcl-2 family proteins and inhibitors of apoptosis. Thus, we hypothesized that the cAMP signaling may modulate DNA repair activity, and we investigated the effects of the cAMP signaling system on {gamma}-ray-induced DNA damage repair in lung cancer cells. Transient expression of a constitutively active mutant of stimulatory G protein (G{alpha}sQL) or treatment with forskolin, an adenylyl cyclase activator, augmented radiation-induced DNA damage and inhibited repair of the damage in H1299 lung cancer cells. Expression of G{alpha}sQL or treatment with forskolin or isoproterenol inhibited the radiation-induced expression of the XRCC1 protein, and exogenous expression of XRCC1 abolished the DNA repair-inhibiting effect of forskolin. Forskolin treatment promoted the ubiquitin and proteasome-dependent degradation of the XRCC1 protein, resulting in a significant decrease in the half-life of the protein after {gamma}-ray irradiation. The effect of forskolin on XRCC1 expression was not inhibited by PKA inhibitor, but 8-pCPT-2 Prime -O-Me-cAMP, an Epac-selective cAMP analog, increased ubiquitination of XRCC1 protein and decreased XRCC1 expression. Knockdown of Epac1 abolished the effect of 8-pCPT-2 Prime -O-Me-cAMP and restored XRCC1 protein level following {gamma}-ray irradiation. From

  6. Genetic dissimilarity of putative gamma-ray-induced 'Preciosa-AAAB-Pome type' banana (Musa sp) mutants based on multivariate statistical analysis.

    PubMed

    Pestana, R K N; Amorim, E P; Ferreira, C F; Amorim, V B O; Oliveira, L S; Ledo, C A S; Silva, S O

    2011-10-25

    Bananas are among the most important fruit crops worldwide, being cultivated in more than 120 countries, mainly by small-scale producers. However, short-stature high-yielding bananas presenting good agronomic characteristics are hard to find. Consequently, wind continues to damage a great number of plantations each year, leading to lodging of plants and bunch loss. Development of new cultivars through conventional genetic breeding methods is hindered by female sterility and the low number of seeds. Mutation induction seems to have great potential for the development of new cultivars. We evaluated genetic dissimilarity among putative 'Preciosa' banana mutants generated by gamma-ray irradiation, using morphoagronomic characteristics and ISSR markers. The genetic distances between the putative 'Preciosa' mutants varied from 0.21 to 0.66, with a cophenetic correlation coefficient of 0.8064. We found good variability after irradiation of 'Preciosa' bananas; this procedure could be useful for banana breeding programs aimed at developing short-stature varieties with good agronomic characteristics.

  7. Electromagnetic Reciprocity.

    SciTech Connect

    Aldridge, David F.

    2014-11-01

    A reciprocity theorem is an explicit mathematical relationship between two different wavefields that can exist within the same space - time configuration. Reciprocity theorems provi de the theoretical underpinning for mod ern full waveform inversion solutions, and also suggest practical strategies for speed ing up large - scale numerical modeling of geophysical datasets . In the present work, several previously - developed electromagnetic r eciprocity theorems are generalized to accommodate a broader range of medi um, source , and receiver types. Reciprocity relations enabling the interchange of various types of point sources and point receivers within a three - dimensional electromagnetic model are derived. Two numerical modeling algorithms in current use are successfully tested for adherence to reciprocity. Finally, the reciprocity theorem forms the point of departure for a lengthy derivation of electromagnetic Frechet derivatives. These mathe matical objects quantify the sensitivity of geophysical electromagnetic data to variatio ns in medium parameters, and thus constitute indispensable tools for solution of the full waveform inverse problem. ACKNOWLEDGEMENTS Sandia National Labor atories is a multi - program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the US Department of Energy's National Nuclear Security Administration under contract DE - AC04 - 94AL85000. Signif icant portions of the work reported herein were conducted under a Cooperative Research and Development Agreement (CRADA) between Sandia National Laboratories (SNL) and CARBO Ceramics Incorporated. The author acknowledges Mr. Chad Cannan and Mr. Terry Pa lisch of CARBO Ceramics, and Ms. Amy Halloran, manager of SNL's Geophysics and Atmospheric Sciences Department, for their interest in and encouragement of this work. Special thanks are due to Dr . Lewis C. Bartel ( recently retired from Sandia National Labo ratories and now a

  8. Reciprocal translocations

    SciTech Connect

    1993-12-31

    Chapter 26, describes reciprocal translocations of chromosomes: their occurrence, breakpoints, and multiple rearrangements. In addition, phenotypes of balanced and unbalanced translocation carriers and fetal death are discussed. Examples of translocation families are given. Meiosis and genetic risk in translocation carriers is presented. Finally, sperm chromosomes in meiotic segregation analysis is mentioned. 39 refs., 3 figs., 1 tab.

  9. X-ray-induced water vaporization

    SciTech Connect

    Weon, B. M.; Lee, J. S.; Je, J. H.; Fezzaa, K.

    2011-09-15

    We present quantitative evidence for x-ray-induced water vaporization: water is vaporized at a rate of 5.5 pL/s with the 1-A-wavelength x-ray irradiation of {approx}0.1 photons per A{sup 2}; moreover, water vapor is reversibly condensed during pauses in irradiation. This result fundamentally suggests that photoionization induces vaporization. This phenomenon is attributed to surface-tension reduction by ionization and would be universally important in radiological and electrohydrodynamic situations.

  10. Manipulation of reciprocal salt bridges at the heterodimerization interface alters the dimerization properties of mouse RXR{alpha} and PPAR{gamma}1

    SciTech Connect

    Chan, Lap Shu; Wells, Richard A. . E-mail: rwells@sri.utoronto.ca

    2007-07-13

    Heterodimerization with RXR is essential for the high-affinity specific binding of multiple nuclear receptors to their cognate DNA sequences. NR dimerization is a two-step process, initiated in solution by interaction between amino acid residues with helices 9 and 10 of the ligand binding domains of RXR and its NR partners. Studies of the orphan nuclear receptor HNF4{alpha}, which forms homodimers exclusively, have indicated that two charged residues in this region, HNF4{alpha}{sub K300} and HNF4{alpha}{sub E327}, are key mediators of dimerization. We have analyzed the contribution of the homologous residues in RXR{alpha} (RXR{alpha}{sub E395}, RXR{alpha}{sub K422}) and PPAR{gamma} (PPAR{gamma}{sub E405}, PPAR{gamma}{sub K432}) to the formation of the RXR{alpha}-PPAR{gamma} heterodimer. Charge reversal mutants of RXR{alpha} (RXR{alpha}{sub E395K}, RXR{alpha}{sub K422E}) and PPAR{gamma} (PPAR{gamma}{sub E405K}, PPAR{gamma}{sub K432E}) show impaired ability to form heterodimers with wild-type PPAR{gamma} and RXR{alpha}, respectively. However, pairs of mutants with balanced charge changes, i.e., RXR{alpha}{sub E395K} with PPAR{gamma}{sub K432E} and RXR{alpha}{sub K422E} with PPAR{gamma}{sub E405K}, are able to form dimers. Ligand response is preserved in the PPAR{gamma} mutants, indicating the mutation does not result in major structural derangement of the protein. These results establish the importance of salt bridges between these residues in the heterodimerization of nuclear receptors, and offer a technical approach to generating functional NR mutants with directed heterodimerization specificity. Such mutants will be valuable tools in the genetic analysis of NR function.

  11. Fermi Large Area Telescope Observations of the Cosmic-Ray Induced

    SciTech Connect

    Abdo, A.

    2012-02-29

    We report on measurements of the cosmic-ray induced {gamma}-ray emission of Earth's atmosphere by the Large Area Telescope onboard the Fermi Gamma-ray Space Telescope. The LAT has observed the Earth during its commissioning phase and with a dedicated Earth-limb following observation in September 2008. These measurements yielded {approx} 6.4 x 10{sup 6} photons with energies > 100 MeV and {approx} 250 hours total livetime for the highest quality data selection. This allows the study of the spatial and spectral distributions of these photons with unprecedented detail. The spectrum of the emission - often referred to as Earth albedo gamma-ray emission - has a power-law shape up to 500 GeV with spectral index {Lambda} = 2.79 {+-} 0.06.

  12. X-ray induced photoacoustic tomography

    NASA Astrophysics Data System (ADS)

    Xiang, Liangzhong; Han, Bin; Carpenter, Colin; Pratx, Guillem; Kuang, Yu; Xing, Lei

    2013-03-01

    X-ray induced photoacoustic tomography, also called X-ray acoustic computer tomography (XACT) is investigated in this paper. Short pulsed (μs-range) X-ray beams from a medical linear accelerator were used to generate ultrasound. The ultrasound signals were collected with an ultrasound transducer (500 KHz central frequency) positioned around an object. The transducer, driven by a computer-controlled step motor to scan around the object, detected the resulting acoustic signals in the imaging plane at each scanning position. A pulse preamplifier, with a bandwidth of 20 KHz-2 MHz at -3 dB, and switchable gains of 40 and 60 dB, received the signals from the transducer and delivered the amplified signals to a secondary amplifier. The secondary amplifier had bandwidth of 20 KHz-30 MHz at -3 dB, and a gain range of 10-60 dB. Signals were recorded and averaged 128 times by an oscilloscope. A sampling rate of 100 MHz was used to record 2500 data points at each view angle. One set of data incorporated 200 positions as the receiver moved 360°. The x-ray generated acoustic image was then reconstructed with the filtered back projection algorithm. The twodimensional XACT images of the lead rod embedded in chicken breast tissue were found to be in good agreement with the shape of the object. This new modality may be useful for a number of applications, such as providing the location of a fiducial, or monitoring x-ray dose distribution during radiation therapy.

  13. β-reciprocal polynomials

    NASA Astrophysics Data System (ADS)

    Withers, Christopher S.; Nadarajah, Saralees

    2016-07-01

    A new class of polynomials pn(x) known as β-reciprocal polynomials is defined. Given a parameter ? that is not a root of -1, we show that the only β-reciprocal polynomials are pn(x) ≡ xn. When β is a root of -1, other polynomials are possible. For example, the Hermite polynomials are i-reciprocal, ?.

  14. Reciprocating pellet press

    DOEpatents

    Jones, Charles W.

    1981-04-07

    A machine for pressing loose powder into pellets using a series of reciprocating motions has an interchangeable punch and die as its only accurately machines parts. The machine reciprocates horizontally between powder receiving and pressing positions. It reciprocates vertically to press, strip and release a pellet.

  15. Reciprocity in directed networks

    NASA Astrophysics Data System (ADS)

    Yin, Mei; Zhu, Lingjiong

    2016-04-01

    Reciprocity is an important characteristic of directed networks and has been widely used in the modeling of World Wide Web, email, social, and other complex networks. In this paper, we take a statistical physics point of view and study the limiting entropy and free energy densities from the microcanonical ensemble, the canonical ensemble, and the grand canonical ensemble whose sufficient statistics are given by edge and reciprocal densities. The sparse case is also studied for the grand canonical ensemble. Extensions to more general reciprocal models including reciprocal triangle and star densities will likewise be discussed.

  16. Reciprocating Linear Electric Motor

    NASA Technical Reports Server (NTRS)

    Goldowsky, M. P.

    1984-01-01

    Features include structural simplicity and good force/displacement characteristics. Reciprocating motor has simple, rugged construction, relatively low reciprocating weight, improved power delivery, and improved force control. Wear reduced by use of magnetic bearings. Intended to provide drivers for long-lived Stirling-cycle cryogenic refrigerators, concept has less exotic applications, such as fuel pumps.

  17. The Structure of Reciprocity

    ERIC Educational Resources Information Center

    Molm, Linda D.

    2010-01-01

    Reciprocity is one of the defining features of social exchange and social life, yet exchange theorists have tended to take it for granted. Drawing on work from a decade-long theoretical research program, I argue that reciprocity is structured and variable across different forms of exchange, that these variations in the structure of reciprocity…

  18. Reciprocity and uncertainty.

    PubMed

    Bereby-Meyer, Yoella

    2012-02-01

    Guala points to a discrepancy between strong negative reciprocity observed in the lab and the way cooperation is sustained "in the wild." This commentary suggests that in lab experiments, strong negative reciprocity is limited when uncertainty exists regarding the players' actions and the intentions. Thus, costly punishment is indeed a limited mechanism for sustaining cooperation in an uncertain environment.

  19. The Value of Reciprocity

    ERIC Educational Resources Information Center

    Molm, Linda D.; Schaefer, David R.; Collett, Jessica L.

    2007-01-01

    The value of reciprocity in social exchange potentially comprises both instrumental value (the value of the actual benefits received from exchange) and communicative or symbolic value (the expressive and uncertainty reduction value conveyed by features of the act of reciprocity itself). While all forms of exchange provide instrumental value, we…

  20. Reciprocal NUT spacetimes

    NASA Astrophysics Data System (ADS)

    Momeni, Davood; Chattopadhyay, Surajit; Myrzakulov, Ratbay

    2015-05-01

    In this paper, we study the Ehlers' transformation (sometimes called gravitational duality rotation) for reciprocal static metrics. First, we introduce the concept of reciprocal metric. We prove a theorem which shows how we can construct a certain new static solution of Einstein field equations using a seed metric. Later, we investigate the family of stationary spacetimes of such reciprocal metrics. The key here is a theorem from Ehlers', which relates any static vacuum solution to a unique stationary metric. The stationary metric has a magnetic charge. The spacetime represents Newman-Unti-Tamburino (NUT) solutions. Since any stationary spacetime can be decomposed into a 1 + 3 time-space decomposition, Einstein field equations for any stationary spacetime can be written in the form of Maxwell's equations for gravitoelectromagnetic fields. Further, we show that this set of equations is invariant under reciprocal transformations. An additional point is that the NUT charge changes the sign. As an instructive example, by starting from the reciprocal Schwarzschild as a spherically symmetric solution and reciprocal Morgan-Morgan disk model as seed metrics we find their corresponding stationary spacetimes. Starting from any static seed metric, performing the reciprocal transformation and by applying an additional Ehlers' transformation we obtain a family of NUT spaces with negative NUT factor (reciprocal NUT factors).

  1. Reciprocity and uncertainty.

    PubMed

    Bereby-Meyer, Yoella

    2012-02-01

    Guala points to a discrepancy between strong negative reciprocity observed in the lab and the way cooperation is sustained "in the wild." This commentary suggests that in lab experiments, strong negative reciprocity is limited when uncertainty exists regarding the players' actions and the intentions. Thus, costly punishment is indeed a limited mechanism for sustaining cooperation in an uncertain environment. PMID:22289307

  2. Hidden patterns of reciprocity.

    PubMed

    Syi

    2014-03-21

    Reciprocity can help the evolution of cooperation. To model both types of reciprocity, we need the concept of strategy. In the case of direct reciprocity there are four second-order action rules (Simple Tit-for-tat, Contrite Tit-for-tat, Pavlov, and Grim Trigger), which are able to promote cooperation. In the case of indirect reciprocity the key component of cooperation is the assessment rule. There are, again, four elementary second-order assessment rules (Image Scoring, Simple Standing, Stern Judging, and Shunning). The eight concepts can be formalized in an ontologically thin way we need only an action predicate and a value function, two agent concepts, and the constant of goodness. The formalism helps us to discover that the action and assessment rules can be paired, and that they show the same patterns. The logic of these patterns can be interpreted with the concept of punishment that has an inherent paradoxical nature.

  3. Hidden patterns of reciprocity.

    PubMed

    Syi

    2014-03-21

    Reciprocity can help the evolution of cooperation. To model both types of reciprocity, we need the concept of strategy. In the case of direct reciprocity there are four second-order action rules (Simple Tit-for-tat, Contrite Tit-for-tat, Pavlov, and Grim Trigger), which are able to promote cooperation. In the case of indirect reciprocity the key component of cooperation is the assessment rule. There are, again, four elementary second-order assessment rules (Image Scoring, Simple Standing, Stern Judging, and Shunning). The eight concepts can be formalized in an ontologically thin way we need only an action predicate and a value function, two agent concepts, and the constant of goodness. The formalism helps us to discover that the action and assessment rules can be paired, and that they show the same patterns. The logic of these patterns can be interpreted with the concept of punishment that has an inherent paradoxical nature. PMID:24368125

  4. Reciprocating piston engine

    SciTech Connect

    Eickmann, K.

    1986-01-07

    This patent describes a reciprocating combustion engine consisting of a cylinder, a piston reciprocating in the cylinder, a top for closing one end of the cylinder, inlets and outlets extending to and from the cylinder for the intake of combustible gas and the expelling of burned exhaust gases. The engine also consists of a device for ignition of the combustible gas, a means of cooling the cylinder and top, a turbine of a turbocharger connected to the outlet, and a compressor of the turbocharger connected to the inlet.

  5. Fermi large area telescope observations of the cosmic-ray induced γ-ray emission of the Earth's atmosphere

    NASA Astrophysics Data System (ADS)

    Abdo, A. A.; Ackermann, M.; Ajello, M.; Atwood, W. B.; Baldini, L.; Ballet, J.; Barbiellini, G.; Bastieri, D.; Baughman, B. M.; Bechtol, K.; Bellazzini, R.; Berenji, B.; Bloom, E. D.; Bonamente, E.; Borgland, A. W.; Bouvier, A.; Bregeon, J.; Brez, A.; Brigida, M.; Bruel, P.; Buehler, R.; Burnett, T. H.; Buson, S.; Caliandro, G. A.; Cameron, R. A.; Caraveo, P. A.; Casandjian, J. M.; Cecchi, C.; Çelik, Ö.; Charles, E.; Chekhtman, A.; Chiang, J.; Ciprini, S.; Claus, R.; Cohen-Tanugi, J.; Conrad, J.; de Palma, F.; Digel, S. W.; Do Couto E Silva, E.; Drell, P. S.; Dubois, R.; Dumora, D.; Farnier, C.; Favuzzi, C.; Fegan, S. J.; Focke, W. B.; Fortin, P.; Frailis, M.; Fukazawa, Y.; Funk, S.; Fusco, P.; Gargano, F.; Gehrels, N.; Germani, S.; Giebels, B.; Giglietto, N.; Giordano, F.; Glanzman, T.; Godfrey, G.; Grenier, I. A.; Grondin, M.-H.; Grove, J. E.; Guillemot, L.; Guiriec, S.; Hays, E.; Horan, D.; Hughes, R. E.; Jóhannesson, G.; Johnson, A. S.; Johnson, T. J.; Johnson, W. N.; Kamae, T.; Katagiri, H.; Kataoka, J.; Kawai, N.; Kerr, M.; Knödlseder, J.; Kuss, M.; Lande, J.; Latronico, L.; Lemoine-Goumard, M.; Longo, F.; Loparco, F.; Lott, B.; Lovellette, M. N.; Lubrano, P.; Makeev, A.; Mazziotta, M. N.; McEnery, J. E.; Meurer, C.; Michelson, P. F.; Mitthumsiri, W.; Mizuno, T.; Monte, C.; Monzani, M. E.; Morselli, A.; Moskalenko, I. V.; Murgia, S.; Nolan, P. L.; Norris, J. P.; Nuss, E.; Ohsugi, T.; Okumura, A.; Omodei, N.; Orlando, E.; Ormes, J. F.; Paneque, D.; Panetta, J. H.; Parent, D.; Pelassa, V.; Pepe, M.; Pesce-Rollins, M.; Piron, F.; Porter, T. A.; Rainò, S.; Rando, R.; Razzano, M.; Reimer, A.; Reimer, O.; Reposeur, T.; Rochester, L. S.; Rodriguez, A. Y.; Roth, M.; Sadrozinski, H. F.-W.; Sander, A.; Saz Parkinson, P. M.; Sgrò, C.; Share, G. H.; Siskind, E. J.; Smith, D. A.; Smith, P. D.; Spandre, G.; Spinelli, P.; Strickman, M. S.; Suson, D. J.; Takahashi, H.; Tanaka, T.; Thayer, J. B.; Thayer, J. G.; Thompson, D. J.; Tibaldo, L.; Torres, D. F.; Tosti, G.; Tramacere, A.; Uchiyama, Y.; Usher, T. L.; Vasileiou, V.; Vilchez, N.; Vitale, V.; Waite, A. P.; Wang, P.; Winer, B. L.; Wood, K. S.; Ylinen, T.; Ziegler, M.

    2009-12-01

    We report on measurements of the cosmic-ray induced γ-ray emission of Earth’s atmosphere by the Large Area Telescope on board the Fermi Gamma-ray Space Telescope. The Large Area Telescope has observed the Earth during its commissioning phase and with a dedicated Earth limb following observation in September 2008. These measurements yielded ˜6.4×106 photons with energies >100MeV and ˜250 hours total live time for the highest quality data selection. This allows the study of the spatial and spectral distributions of these photons with unprecedented detail. The spectrum of the emission—often referred to as Earth albedo gamma-ray emission—has a power-law shape up to 500 GeV with spectral index Γ=2.79±0.06.

  6. Series of Reciprocal Triangular Numbers

    ERIC Educational Resources Information Center

    Bruckman, Paul; Dence, Joseph B.; Dence, Thomas P.; Young, Justin

    2013-01-01

    Reciprocal triangular numbers have appeared in series since the very first infinite series were summed. Here we attack a number of subseries of the reciprocal triangular numbers by methodically expressing them as integrals.

  7. Reciprocal Predicates in Japanese.

    ERIC Educational Resources Information Center

    Ishii, Yasuo

    A study of reciprocals in Japanese compares two kinds: (1) a verbal suffix "aw"; and (2) an NP argument "otagai." Although "otagai" appears to be taken care of by syntactic binding theory, it is proposed that there is no evidence for the existence of a syntactic position of the object NP in the case of "aw." The suffix can be characterized as…

  8. Reciprocity relations in aerodynamics

    NASA Technical Reports Server (NTRS)

    Heaslet, Max A; Spreiter, John R

    1953-01-01

    Reverse flow theorems in aerodynamics are shown to be based on the same general concepts involved in many reciprocity theorems in the physical sciences. Reciprocal theorems for both steady and unsteady motion are found as a logical consequence of this approach. No restrictions on wing plan form or flight Mach number are made beyond those required in linearized compressible-flow analysis. A number of examples are listed, including general integral theorems for lifting, rolling, and pitching wings and for wings in nonuniform downwash fields. Correspondence is also established between the buildup of circulation with time of a wing starting impulsively from rest and the buildup of lift of the same wing moving in the reverse direction into a sharp-edged gust.

  9. Contractor safety training reciprocity

    SciTech Connect

    Melancon, R.

    1996-08-01

    In June, 1995, the National Petroleum Refiners Association (NPRA) adhoc committee on Contractor Safety Training, turned over the task of developing reciprocity agreements with all Contractor Safety Training Councils to the Executive Directors of each of the Council`s. The Council representatives were to develop these agreements based on the NPRA adhoc committee training objectives that were developed jointly by representatives of the petroleum industry, chemical industry, contractors and the Council`s.

  10. CMOS RAM cosmic-ray-induced-error-rate analysis

    NASA Technical Reports Server (NTRS)

    Pickel, J. C.; Blandford, J. T., Jr.

    1981-01-01

    A significant number of spacecraft operational anomalies are believed to be associated with cosmic-ray-induced soft errors in the LSI memories. Test programs using a cyclotron to simulate cosmic rays have established conclusively that many common commercial memory types are vulnerable to heavy-ion upset. A description is given of the methodology and the results of a detailed analysis for predicting the bit-error rate in an assumed space environment for CMOS memory devices. Results are presented for three types of commercially available CMOS 1,024-bit RAMs. It was found that the HM6508 is susceptible to single-ion induced latchup from argon and krypton ions. The HS6508 and HS6508RH and the CDP1821 apparently are not susceptible to single-ion induced latchup.

  11. High Resolution X-ray-Induced Acoustic Tomography

    NASA Astrophysics Data System (ADS)

    Xiang, Liangzhong; Tang, Shanshan; Ahmad, Moiz; Xing, Lei

    2016-05-01

    Absorption based CT imaging has been an invaluable tool in medical diagnosis, biology, and materials science. However, CT requires a large set of projection data and high radiation dose to achieve superior image quality. In this letter, we report a new imaging modality, X-ray Induced Acoustic Tomography (XACT), which takes advantages of high sensitivity to X-ray absorption and high ultrasonic resolution in a single modality. A single projection X-ray exposure is sufficient to generate acoustic signals in 3D space because the X-ray generated acoustic waves are of a spherical nature and propagate in all directions from their point of generation. We demonstrate the successful reconstruction of gold fiducial markers with a spatial resolution of about 350 μm. XACT reveals a new imaging mechanism and provides uncharted opportunities for structural determination with X-ray.

  12. High Resolution X-ray-Induced Acoustic Tomography

    PubMed Central

    Xiang, Liangzhong; Tang, Shanshan; Ahmad, Moiz; Xing, Lei

    2016-01-01

    Absorption based CT imaging has been an invaluable tool in medical diagnosis, biology, and materials science. However, CT requires a large set of projection data and high radiation dose to achieve superior image quality. In this letter, we report a new imaging modality, X-ray Induced Acoustic Tomography (XACT), which takes advantages of high sensitivity to X-ray absorption and high ultrasonic resolution in a single modality. A single projection X-ray exposure is sufficient to generate acoustic signals in 3D space because the X-ray generated acoustic waves are of a spherical nature and propagate in all directions from their point of generation. We demonstrate the successful reconstruction of gold fiducial markers with a spatial resolution of about 350 μm. XACT reveals a new imaging mechanism and provides uncharted opportunities for structural determination with X-ray. PMID:27189746

  13. An ultrafast reciprocating probe

    NASA Astrophysics Data System (ADS)

    Liu, Wenbin; Tan, Yi; Wang, Wenhao; Gao, Zhe

    2016-11-01

    For tokamak plasma diagnostics, an ultrafast reciprocating probe system driven by magnetic field coils, achieving a maximum velocity of 21 m/s, is introduced. The probes are attached with a driving hoop made of carbon steel and accelerated by three acceleration coils in series, then decelerated by two deceleration coils and buffer springs and return slowly. The coils with a current of about 1 kA generate a magnetic field of about 1 T. This probe system has been tested on the SUNIST (Sino-UNIted Spherical Tokamak) spherical tokamak. Radial profiles of the floating potential and other plasma parameters measured by this probe system are given.

  14. High pressure reciprocating pump

    SciTech Connect

    Besic, D.

    1990-05-01

    This patent describes an improvement in a reciprocating pump having a plunger and a pumping chamber. It comprises: the plunger having a bore communicating with an intersection opening and wherein the plunger incudes a central axis; a suction valve and a discharge valve, each having an axis of actuation parallel to a central axis of the plunger; the suction valve comprising a cylindrical core having a central passageway, and the core is slidably received by a seating member and resiliently biased to the seating member.

  15. Reciprocating magnetic refrigerator

    NASA Technical Reports Server (NTRS)

    Johnson, D. L.

    1985-01-01

    A 4 to 15 K magnetic refrigerator to test as an alternative to the Joule-Thomson circuit as the low temperature stage of a 4 to 300 K closed-cycle refrigerator was developed. The reciprocating magnetic refrigerator consists of two matrices of gadolinium gallium garnet spheres located in tandem on a single piston which alternately moves each matrix into a 7 telsa magnetic field. A separate helium gas circuit is used as the heat exchange mechanism for the low and the high temperature extremes of the magnetic refrigerator. Details of the design and results of the initial refrigerator component tests are presented.

  16. Reciprocal relations in electroacoustics

    SciTech Connect

    Chassagne, C.; Bedeaux, D.

    2014-07-28

    In a colloidal suspension, one can generate sound waves by the application of an alternating electric field (Electrokinetic Sonic Amplitude, i.e., ESA). Another phenomenon is electrophoresis (Electrophoretic Mobility, i.e., EM) where a colloidal particle moves relative to the solvent in an electric field. Vice versa one can generate electric fields or electric currents by sound waves (Colloid Vibration Potential/Current, i.e., CVP/CVI). In 1988 and 1990, O’Brien [J. Fluid Mech. 190, 71–86 (1988) and O’Brien, J. Fluid Mech. 212, 81–93 (1990)] derived a reciprocal relation between the proportionality coefficients of the EM and CVI phenomena. In this paper, we will generalize his proof by constructing the relevant entropy production from which the linear force-flux relations follow. General relations are derived for electrolyte solutions, of which colloidal suspensions are a particular case. The relations between CVI, CVP, EM, and ESA are discussed. O’Brien's reciprocal relation then follows as an Onsager relation. The relation is valid for any applied electric field frequency, particle surface charge and particle concentration (even in the presence of particle-particle interactions) provided the system is isotropic.

  17. X-ray-induced changes in growth of Mozambique tilapia

    SciTech Connect

    Jana, B.B.; Basu, M.

    1995-01-01

    Early fry (30 d postfertilization) and 7-8-week-old Mozambique tilapias (Tilapia mossambica) were exposed to X rays in dosages of 50, 100, 200, 300, 400 or 500 roentgens and reared in outdoor culture tanks between May 1981 and October 1988. Fish of either sex that were irradiated as fry grew faster than controls at all test X-ray doses. Among fish irradiated at 7-8 weeks, males grew significantly faster, but females grew significantly slower, than controls at all test doses. X-ray-induced changes in growth were dose-dependent: growth rates of fry (both sexes) and of juvenile males rose relative to those of controls with increased radiation dose. The growth increase per unit of radiation dose was higher for fry than for older juveniles. The length-weight regression was steeper for irradiated males than for controls. The average weights of F{sub 1} offspring of irradiated fish were greatly reduced as compared with controls, which suggests the transfer of the detrimental effects of X rays from irradiated parents to their offspring. 39 refs., 3 figs., 3 tabs.

  18. Toward a Behavior of Reciprocity

    PubMed Central

    Gernsbacher, Morton Ann

    2014-01-01

    It is frequently believed that autism is characterized by a lack of social or emotional reciprocity. In this article, I question that assumption by demonstrating how many professionals—researchers and clinicians—and likewise many parents, have neglected the true meaning of reciprocity. Reciprocity is “a relation of mutual dependence or action or influence,” or “a mode of exchange in which transactions take place between individuals who are symmetrically placed.” Assumptions by clinicians and researchers suggest that they have forgotten that reciprocity needs to be mutual and symmetrical—that reciprocity is a two-way street. Research is reviewed to illustrate that when professionals, peers, and parents are taught to act reciprocally, autistic children become more responsive. In one randomized clinical trial of “reciprocity training” to parents, their autistic children's language developed rapidly and their social engagement increased markedly. Other demonstrations of how parents and professionals can increase their behavior of reciprocity are provided. PMID:25598865

  19. Muon content of gamma ray induced EAS from Cygnus X-3

    NASA Technical Reports Server (NTRS)

    Blake, P. R.; Nash, W. F.; Saich, M. R.; Stanley, G. B.

    1985-01-01

    During 1984 the Leeds group (Lambert et al, OG 2,1-6) have observed emission above 5 times 10 to the 14th power eV in July, September and October at phi approximately 0.6. These observations were made with an array which included the Nottingham 10 sq m muon detector. A search for muons in events at the phase peak and off source has yielded the following results: (1) for 42 on source events we find an average muon density of 0.63 muons m(-2) at a mean core distance Bar R = 32 m and mean primary energy approximately 25 times 10 to the 15th power eV; (2) for 21 off source events average muon density = 1.6 m(-2), Bar R = 32 m with mean primary energy approximately 2.0 x 10 to the 15th power eV; (3) for 11 of the 42 on source events, zero muons were recorded in the 10 sq ms. For these events Bar R = 41 m and mean primary energy approximately 1.5 x 10 to the 15th power eV; (4) for 8 of the 21 off source events, zero muons were recorded in the 10 sq ms. For these events Bar R = 37 m and mean primary energy approximately 1.5 times 10 to the 15th power eV. For all the events the mean zenith angle was approximately 16 deg. A more detailed comparison of on source and further off source events will be presented.

  20. Search for cosmic-ray-induced gamma-ray emission in galaxy clusters

    SciTech Connect

    Ackermann, M.; Buehler, R.; Ajello, M.; Albert, A.; Allafort, A.; Bechtol, K.; Bloom, E. D.; Bottacini, E.; Atwood, W. B.; Baldini, L.; Ballet, J.; Bastieri, D.; Buson, S.; Bellazzini, R.; Bregeon, J.; Bonamente, E.; Brandt, T. J.; Brigida, M.; Bruel, P. E-mail: zimmer@fysik.su.se E-mail: apinzke@fysik.su.se [Laboratoire Leprince-Ringuet, École polytechnique, CNRS Collaboration: Fermi-LAT Collaboration; and others

    2014-05-20

    Current theories predict relativistic hadronic particle populations in clusters of galaxies in addition to the already observed relativistic leptons. In these scenarios hadronic interactions give rise to neutral pions which decay into γ rays that are potentially observable with the Large Area Telescope (LAT) on board the Fermi space telescope. We present a joint likelihood analysis searching for spatially extended γ-ray emission at the locations of 50 galaxy clusters in four years of Fermi-LAT data under the assumption of the universal cosmic-ray (CR) model proposed by Pinzke and Pfrommer. We find an excess at a significance of 2.7σ, which upon closer inspection, however, is correlated to individual excess emission toward three galaxy clusters: A400, A1367, and A3112. We discuss these cases in detail and conservatively attribute the emission to unmodeled background systems (for example, radio galaxies within the clusters).Through the combined analysis of 50 clusters, we exclude hadronic injection efficiencies in simple hadronic models above 21% and establish limits on the CR to thermal pressure ratio within the virial radius, R {sub 200}, to be below 1.25%-1.4% depending on the morphological classification. In addition, we derive new limits on the γ-ray flux from individual clusters in our sample.

  1. Trust, Respect, and Reciprocity

    PubMed Central

    Phong, Tran Viet; Nhan, Le Nguyen Thanh; Dung, Nguyen Thanh; Ngan, Ta Thi Dieu; Kinh, Nguyen Van; Parker, Michael; Bull, Susan

    2015-01-01

    International science funders and publishers are driving a growing trend in data sharing. There is mounting pressure on researchers in low- and middle-income settings to conform to new sharing policies, despite minimal empirically grounded accounts of the ethical challenges of implementing the policies in these settings. This study used in-depth interviews and focus group discussions with 48 stakeholders in Vietnam to explore the experiences, attitudes, and expectations that inform ethical and effective approaches to sharing clinical research data. Distinct views on the role of trust, respect, and reciprocity were among those that emerged to inform culturally appropriate best practices. We conclude by discussing the challenges that authors of data-sharing policies should consider in this unique context. PMID:26297747

  2. Reciprocating linear motor

    NASA Technical Reports Server (NTRS)

    Goldowsky, Michael P. (Inventor)

    1987-01-01

    A reciprocating linear motor is formed with a pair of ring-shaped permanent magnets having opposite radial polarizations, held axially apart by a nonmagnetic yoke, which serves as an axially displaceable armature assembly. A pair of annularly wound coils having axial lengths which differ from the axial lengths of the permanent magnets are serially coupled together in mutual opposition and positioned with an outer cylindrical core in axial symmetry about the armature assembly. One embodiment includes a second pair of annularly wound coils serially coupled together in mutual opposition and an inner cylindrical core positioned in axial symmetry inside the armature radially opposite to the first pair of coils. Application of a potential difference across a serial connection of the two pairs of coils creates a current flow perpendicular to the magnetic field created by the armature magnets, thereby causing limited linear displacement of the magnets relative to the coils.

  3. Reciprocating wind engine

    SciTech Connect

    Van Mechelen, B.

    1980-12-09

    A reciprocating wind engine is described which utilizes plural, movably mounted sets of panels to form pistons. Cooperating first and second pistons may be spaced from each other on either side of a central crankshaft. As the wind strikes the surface of a first set of panels, the first piston is moved toward the crankshaft and the second piston is pulled toward the crankshaft from the opposite side. When both pistons are adjacent the crankshaft, the panels on the first or windward piston open to allow the wind to pass therethrough into contact with the panels of the second piston which are closed to present a uniform surface to the wind. The pistons are forced away from the crankshaft to complete one cycle of operation. The output from the crankshaft may be utilized to generate electricity, or for any other suitable purpose. Plural engine segments may be cooperatively joined together to form a bank of such units.

  4. Upstream reciprocity in heterogeneous networks.

    PubMed

    Iwagami, Akio; Masuda, Naoki

    2010-08-01

    Many mechanisms for the emergence and maintenance of altruistic behavior in social dilemma situations have been proposed. Indirect reciprocity is one such mechanism, where other-regarding actions of a player are eventually rewarded by other players with whom the original player has not interacted. The upstream reciprocity (also called generalized indirect reciprocity) is a type of indirect reciprocity and represents the concept that those helped by somebody will help other unspecified players. In spite of the evidence for the enhancement of helping behavior by upstream reciprocity in rats and humans, theoretical support for this mechanism is not strong. In the present study, we numerically investigate upstream reciprocity in heterogeneous contact networks, in which the players generally have different number of neighbors. We show that heterogeneous networks considerably enhance cooperation in a game of upstream reciprocity. In heterogeneous networks, the most generous strategy, by which a player helps a neighbor on being helped and in addition initiates helping behavior, first occupies hubs in a network and then disseminates to other players. The scenario to achieve enhanced altruism resembles that seen in the case of the Prisoner's Dilemma game in heterogeneous networks.

  5. Healthy reciprocity in sexual interaction.

    PubMed

    Heino, J; Ojanlatva, A

    2000-02-01

    The purpose of the article is to discuss reciprocity in sexual interaction within a couple relationship in which heterosexual orientation is assumed and satisfaction considered. Reciprocity is modelled as an exchange of services which at its best functions as an unwritten contract, a mutual understanding regarding fairness of returned services, and a desire to comply with this principle together with a loved one/lover. An equal treatment of and balanced attitudes towards one another are present together with a just distribution of benefits and concessions or compromises. Reciprocity involves a relative term although healthy reciprocity can be defined for discussion and assessed as a degree of mutual satisfaction. Sexual interaction issues, skills to obtain satisfaction, and sexual and emotional compatibility are important elements in reciprocity. Understandable communication is an essential contributor in the implementation of reciprocity. Conflict-making dialogue should generally be avoided and connotive meanings of words taken into account. Erotophilia-erotophobia dimensions influence both the learning about and attitudes towards sexuality and contribute to personal and professional abilities to assess sexual problems and to attend to them. Erotic touch is a minimum requirement of love making. Sexual orientation, sexual desire, and intimacy influence sexual compatibility. Equity and exchange models are discussed, and a reciprocity model is proposed.

  6. Pulsar and diffuse contributions to observed galactic gamma radiation

    NASA Technical Reports Server (NTRS)

    Harding, A. K.; Stecker, F. W.

    1981-01-01

    The first calculation of a gamma-ray production spectrum from pulsars in the Galaxy, along with a statistical analysis of data on 328 known radio pulsars, are presented. The implications of this point source contribution to the general interpretation of the observed galactic gamma-ray spectrum are indicated. The contributions from diffuse interstellar cosmic-ray induced production mechanisms are then re-examined, concluding that pulsars may be contributing significantly to the galactic gamma-ray emission.

  7. Direct reciprocity in spatial populations enhances R-reciprocity as well as ST-reciprocity.

    PubMed

    Miyaji, Kohei; Tanimoto, Jun; Wang, Zhen; Hagishima, Aya; Ikegaya, Naoki

    2013-01-01

    As is well-known, spatial reciprocity plays an important role in facilitating the emergence of cooperative traits, and the effect of direct reciprocity is also obvious for explaining the cooperation dynamics. However, how the combination of these two scenarios influences cooperation is still unclear. In the present work, we study the evolution of cooperation in 2 × 2 games via considering both spatial structured populations and direct reciprocity driven by the strategy with 1-memory length. Our results show that cooperation can be significantly facilitated on the whole parameter plane. For prisoner's dilemma game, cooperation dominates the system even at strong dilemma, where maximal social payoff is still realized. In this sense, R-reciprocity forms and it is robust to the extremely strong dilemma. Interestingly, when turning to chicken game, we find that ST-reciprocity is also guaranteed, through which social average payoff and cooperation is greatly enhanced. This reciprocity mechanism is supported by mean-field analysis and different interaction topologies. Thus, our study indicates that direct reciprocity in structured populations can be regarded as a more powerful factor for the sustainability of cooperation.

  8. Direct reciprocity in spatial populations enhances R-reciprocity as well as ST-reciprocity.

    PubMed

    Miyaji, Kohei; Tanimoto, Jun; Wang, Zhen; Hagishima, Aya; Ikegaya, Naoki

    2013-01-01

    As is well-known, spatial reciprocity plays an important role in facilitating the emergence of cooperative traits, and the effect of direct reciprocity is also obvious for explaining the cooperation dynamics. However, how the combination of these two scenarios influences cooperation is still unclear. In the present work, we study the evolution of cooperation in 2 × 2 games via considering both spatial structured populations and direct reciprocity driven by the strategy with 1-memory length. Our results show that cooperation can be significantly facilitated on the whole parameter plane. For prisoner's dilemma game, cooperation dominates the system even at strong dilemma, where maximal social payoff is still realized. In this sense, R-reciprocity forms and it is robust to the extremely strong dilemma. Interestingly, when turning to chicken game, we find that ST-reciprocity is also guaranteed, through which social average payoff and cooperation is greatly enhanced. This reciprocity mechanism is supported by mean-field analysis and different interaction topologies. Thus, our study indicates that direct reciprocity in structured populations can be regarded as a more powerful factor for the sustainability of cooperation. PMID:23951272

  9. Social evolution: reciprocity there is.

    PubMed

    Taborsky, Michael

    2013-06-01

    The theory of cooperation predicts that altruism can be established by reciprocity, yet empirical evidence from nature is contentious. Increasingly though, experimental results from social vertebrates challenge the nearly exclusive explanatory power of relatedness for the evolution of cooperation.

  10. Group formation through indirect reciprocity

    NASA Astrophysics Data System (ADS)

    Oishi, Koji; Shimada, Takashi; Ito, Nobuyasu

    2013-03-01

    The emergence of group structure of cooperative relations is studied in an agent-based model. It is proved that specific types of reciprocity norms lead individuals to split into two groups only inside of which they are cooperative. The condition for the evolutionary stability of the norms is also obtained. This result suggests reciprocity norms, which usually promote cooperation, can cause society's separation into multiple groups.

  11. Moral assessment in indirect reciprocity.

    PubMed

    Sigmund, Karl

    2012-04-21

    Indirect reciprocity is one of the mechanisms for cooperation, and seems to be of particular interest for the evolution of human societies. A large part is based on assessing reputations and acting accordingly. This paper gives a brief overview of different assessment rules for indirect reciprocity, and studies them by using evolutionary game dynamics. Even the simplest binary assessment rules lead to complex outcomes and require considerable cognitive abilities.

  12. Gamma-gamma colliders

    SciTech Connect

    Kim, K.J.; Sessler, A.

    1996-06-01

    Gamma-gamma colliders make intense beams of gamma rays and have them collide so as to make elementary particles. The authors show, in this article, that constructing a gamma-gamma collider as an add-on to an electron-positron linear collider is possible with present technology and that it does not require much additional cost. Furthermore, they show that the resulting capability is very interesting from a particle physics point of view. An overview of a linear collider, with a second interaction region devoted to {gamma}{gamma} collisions is shown.

  13. Direct reciprocity in structured populations.

    PubMed

    van Veelen, Matthijs; García, Julián; Rand, David G; Nowak, Martin A

    2012-06-19

    Reciprocity and repeated games have been at the center of attention when studying the evolution of human cooperation. Direct reciprocity is considered to be a powerful mechanism for the evolution of cooperation, and it is generally assumed that it can lead to high levels of cooperation. Here we explore an open-ended, infinite strategy space, where every strategy that can be encoded by a finite state automaton is a possible mutant. Surprisingly, we find that direct reciprocity alone does not lead to high levels of cooperation. Instead we observe perpetual oscillations between cooperation and defection, with defection being substantially more frequent than cooperation. The reason for this is that "indirect invasions" remove equilibrium strategies: every strategy has neutral mutants, which in turn can be invaded by other strategies. However, reciprocity is not the only way to promote cooperation. Another mechanism for the evolution of cooperation, which has received as much attention, is assortment because of population structure. Here we develop a theory that allows us to study the synergistic interaction between direct reciprocity and assortment. This framework is particularly well suited for understanding human interactions, which are typically repeated and occur in relatively fluid but not unstructured populations. We show that if repeated games are combined with only a small amount of assortment, then natural selection favors the behavior typically observed among humans: high levels of cooperation implemented using conditional strategies.

  14. Indirect Reciprocity; A Field Experiment

    PubMed Central

    van Apeldoorn, Jacobien; Schram, Arthur

    2016-01-01

    Indirect reciprocity involves cooperative acts towards strangers, either in response to their kindness to third parties (downstream) or after receiving kindness from others oneself (upstream). It is considered to be important for the evolution of cooperative behavior amongst humans. Though it has been widely studied theoretically, the empirical evidence of indirect reciprocity has thus far been limited and based solely on behavior in laboratory experiments. We provide evidence from an online environment where members can repeatedly ask and offer services to each other, free of charge. For the purpose of this study we created several new member profiles, which differ only in terms of their serving history. We then sent out a large number of service requests to different members from all over the world. We observe that a service request is more likely to be rewarded for those with a profile history of offering the service (to third parties) in the past. This provides clear evidence of (downstream) indirect reciprocity. We find no support for upstream indirect reciprocity (in this case, rewarding the service request after having previously received the service from third parties), however. Our evidence of downstream indirect reciprocity cannot be attributed to reputational effects concerning one’s trustworthiness as a service user. PMID:27043712

  15. Assortment and the evolution of generalized reciprocity.

    PubMed

    Rankin, Daniel J; Taborsky, Michael

    2009-07-01

    Reciprocity is often invoked to explain cooperation. Reciprocity is cognitively demanding, and both direct and indirect reciprocity require that individuals store information about the propensity of their partners to cooperate. By contrast, generalized reciprocity, wherein individuals help on the condition that they received help previously, only relies on whether an individual received help in a previous encounter. Such anonymous information makes generalized reciprocity hard to evolve in a well-mixed population, as the strategy will lose out to pure defectors. Here we analyze a model for the evolution of generalized reciprocity, incorporating assortment of encounters, to investigate the conditions under which it will evolve. We show that, in a well-mixed population, generalized reciprocity cannot evolve. However, incorporating assortment of encounters can favor the evolution of generalized reciprocity in which indiscriminate cooperation and defection are both unstable. We show that generalized reciprocity can evolve under both the prisoner's dilemma and the snowdrift game.

  16. Kinetic Modeling of the X-ray-induced Damage to a Metalloprotein

    PubMed Central

    Davis, Katherine M.; Kosheleva, Irina; Henning, Robert W.; Seidler, Gerald T.; Pushkar, Yulia

    2013-01-01

    It is well known that biological samples undergo x-ray-induced degradation. One of the fastest occurring x-ray-induced processes involves redox modifications (reduction or oxidation) of redox-active cofactors in proteins. Here we analyze room temperature data on the photoreduction of Mn ions in the oxygen evolving complex (OEC) of photosystem II, one of the most radiation damage sensitive proteins and a key constituent of natural photosynthesis in plants, green algae and cyanobacteria. Time-resolved x-ray emission spectroscopy with wavelength-dispersive detection was used to collect data on the progression of x-ray-induced damage. A kinetic model was developed to fit experimental results, and the rate constant for the reduction of OEC MnIII/IV ions by solvated electrons was determined. From this model, the possible kinetics of x-ray-induced damage at variety of experimental conditions, such as different rates of dose deposition as well as different excitation wavelengths, can be inferred. We observed a trend of increasing dosage threshold prior to the onset of x-ray-induced damage with increasing rates of damage deposition. This trend suggests that experimentation with higher rates of dose deposition is beneficial for measurements of biological samples sensitive to radiation damage, particularly at pink beam and x-ray FEL sources. PMID:23815809

  17. Monte-Carlo gamma response simulation of fast/thermal neutron interactions with soil elements

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Soil elemental analysis using characteristic gamma rays induced by neutrons is an effective method of in situ soil content determination. The nuclei of soil elements irradiated by neutrons issue characteristic gamma rays due to both inelastic neutron scattering (e.g., Si, C) and thermal neutron capt...

  18. Determination of the cosmic-ray-induced neutron flux and ambient dose equivalent at flight altitude

    NASA Astrophysics Data System (ADS)

    Pazianotto, M. T.; Cortés-Giraldo, M. A.; Federico, C. A.; Gonçalez, O. L.; Quesada, J. M.; Carlson, B. V.

    2015-07-01

    There is interest in modeling the atmosphere in the South Atlantic Magnetic Anomaly in order to obtain information about the cosmic-ray induced neutron spectrum and angular distribution as functions of altitude. In this work we use the Monte Carlo codes MCNPX and Geant4 to determine the cosmic-ray-induced neutron flux in the atmosphere produced by the cosmic ray protons incident on the top of the atmosphere and to estimate the ambient dose equivalent rate as function of altitude. The results present a reasonable conformity to other codes (QARM and EXPACS) based on other parameterizations.

  19. Indirect reciprocity with optional interactions.

    PubMed

    Ghang, Whan; Nowak, Martin A

    2015-01-21

    Indirect reciprocity is a mechanism for the evolution of cooperation that is relevant for prosocial behavior among humans. Indirect reciprocity means that my behavior towards you also depends on what you have done to others. Indirect reciprocity is associated with the evolution of social intelligence and human language. Most approaches to indirect reciprocity assume obligatory interactions, but here we explore optional interactions. In any one round a game between two players is offered. A cooperator accepts a game unless the reputation of the other player indicates a defector. For a game to take place, both players must accept. In a game between a cooperator and a defector, the reputation of the defector is revealed to all players with probability Q. After a sufficiently large number of rounds the identity of all defectors is known and cooperators are no longer exploited. The crucial condition for evolution of cooperation can be written as hQB>1, where h is the average number of rounds per person and B=(b/c)-1 specifies the benefit-to-cost ratio. We analyze both stochastic and deterministic evolutionary game dynamics. We study two extensions that deal with uncertainty: hesitation and malicious gossip.

  20. Do infants detect indirect reciprocity?

    PubMed

    Meristo, Marek; Surian, Luca

    2013-10-01

    In social interactions involving indirect reciprocity, agent A acts prosocially towards B and this prompts C to act prosocially towards A. This happens because A's actions enhanced its reputation in the eyes of third parties. Indirect reciprocity may have been of central importance in the evolution of morality as one of the major mechanisms leading to the selection of helping and fair attitudes. Here we show that 10-month-old infants expect third parties to act positively towards fair donors who have distributed attractive resources equally between two recipients, rather than toward unfair donors who made unequal distributions. Infants' responses were dependent on the reciprocator's perceptual exposure to previous relevant events: they expected the reciprocator to reward the fair donor only when it had seen the distributive actions performed by the donors. We propose that infants were able to generate evaluations of agents that were based on the fairness of their distributive actions and to generate expectations about the social preferences of informed third parties.

  1. Indirect reciprocity under incomplete observation.

    PubMed

    Nakamura, Mitsuhiro; Masuda, Naoki

    2011-07-01

    Indirect reciprocity, in which individuals help others with a good reputation but not those with a bad reputation, is a mechanism for cooperation in social dilemma situations when individuals do not repeatedly interact with the same partners. In a relatively large society where indirect reciprocity is relevant, individuals may not know each other's reputation even indirectly. Previous studies investigated the situations where individuals playing the game have to determine the action possibly without knowing others' reputations. Nevertheless, the possibility that observers of the game, who generate the reputation of the interacting players, assign reputations without complete information about them has been neglected. Because an individual acts as an interacting player and as an observer on different occasions if indirect reciprocity is endogenously sustained in a society, the incompleteness of information may affect either role. We examine the game of indirect reciprocity when the reputations of players are not necessarily known to observers and to interacting players. We find that the trustful discriminator, which cooperates with good and unknown players and defects against bad players, realizes cooperative societies under seven social norms. Among the seven social norms, three of the four suspicious norms under which cooperation (defection) to unknown players leads to a good (bad) reputation enable cooperation down to a relatively small observation probability. In contrast, the three trustful norms under which both cooperation and defection to unknown players lead to a good reputation are relatively efficient.

  2. Reciprocity theory of homogeneous reactions

    NASA Astrophysics Data System (ADS)

    Agbormbai, Adolf A.

    1990-03-01

    The reciprocity formalism is applied to the homogeneous gaseous reactions in which the structure of the participating molecules changes upon collision with one another, resulting in a change in the composition of the gas. The approach is applied to various classes of dissociation, recombination, rearrangement, ionizing, and photochemical reactions. It is shown that for the principle of reciprocity to be satisfied it is necessary that all chemical reactions exist in complementary pairs which consist of the forward and backward reactions. The backward reaction may be described by either the reverse or inverse process. The forward and backward processes must satisfy the same reciprocity equation. Because the number of dynamical variables is usually unbalanced on both sides of a chemical equation, it is necessary that this balance be established by including as many of the dynamical variables as needed before the reciprocity equation can be formulated. Statistical transformation models of the reactions are formulated. The models are classified under the titles free exchange, restricted exchange and simplified restricted exchange. The special equations for the forward and backward processes are obtained. The models are consistent with the H theorem and Le Chatelier's principle. The models are also formulated in the context of the direct simulation Monte Carlo method.

  3. Reciprocity and Humility in Wonderland

    ERIC Educational Resources Information Center

    Harry, Beth

    2011-01-01

    This article supports the perspective of Jan Valle regarding the importance of recognizing the subjectivity inherent in decisions about Learning Disabilities. The author argues that the perspectives of both parents and professionals are informed by subjective judgments that must be taken into account in decision making. A reciprocal approach to…

  4. An Inquiry into Relationship Suicides and Reciprocity

    ERIC Educational Resources Information Center

    Davis, Mark S.; Callanan, Valerie J.; Lester, David; Haines, Janet

    2009-01-01

    Few theories on suicide have been grounded in the norm of reciprocity. There is literature on suicide, however, describing motivations such as retaliation and retreat which can be interpreted as modes of adaptation to the norm of reciprocity. We propose a reciprocity-based theory to explain suicides associated with relationship problems. Employing…

  5. 47 CFR 51.221 - Reciprocal compensation.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 47 Telecommunication 3 2010-10-01 2010-10-01 false Reciprocal compensation. 51.221 Section 51.221... Obligations of All Local Exchange Carriers § 51.221 Reciprocal compensation. The rules governing reciprocal compensation are set forth in subpart H of this part....

  6. Capuchin Monkeys Judge Third-Party Reciprocity

    ERIC Educational Resources Information Center

    Anderson, James R.; Takimoto, Ayaka; Kuroshima, Hika; Fujita, Kazuo

    2013-01-01

    Increasing interest is being shown in how children develop an understanding of reciprocity in social exchanges and fairness in resource distribution, including social exchanges between third parties. Although there are descriptions of reciprocity on a one-to-one basis in other species, whether nonhumans detect reciprocity and violations of…

  7. Search for X-ray induced decay of the 31-yr isomer of 178Hf using synchrotron radiation

    SciTech Connect

    Ahmad, I; Banar, J C; Becker, J A; Bredeweg, T A; Cooper, J R; Gemmell, D S; Kraemer, A; Mashayekhi, A; McNabb, D P; Miller, G G; Moore, E F; Palmer, P; Pangault, L N; Rundberg, R S; Schiffer, J P; Shastri, S D; Wang, T F; Wilhelmy, J B

    2004-09-13

    Isomeric {sup 178}Hf (t{sub 1/2} = 31 yr, E{sub x} = 2.446 MeV, J{sup {pi}} = 16{sup +}) was bombarded by a white beam of x-rays from the Advanced Photon Source at Argonne National Laboratory. A search was made for x-ray induced decay of the isomer by detecting prompt and delayed {gamma} rays associated with the decay. No induced decay was observed. Upper limits for such a process for x-ray energies between 7-100 keV were set. The limits between 7 and 30 keV are below {approx} 3 x 10{sup -27} cm{sup 2}-keV for induced decay that bypasses the 4-s isomer and {approx} 5 x 10{sup -27} cm{sup 2}-keV for induced decay that is delayed through this isomer, orders of magnitude below values at which induced decay was reported previously. These limits are consistent with what is known about the properties of atomic nuclei.

  8. Pulsar and diffuse contributions to the observed galactic gamma radiation

    NASA Technical Reports Server (NTRS)

    Harding, A. K.; Stecker, F. W.

    1980-01-01

    With the acquisition of satellite data on the energy spectrum of galactic gamma-radiation, it is clear that such radiation has a multicomponent nature. A calculation of the pulsar gamma ray emission spectrum is used together with a statistical analysis of recent data on 328 known pulsars to make a new determination of the pulsar contribution to galactic gamma ray emission. The contributions from diffuse interstellar cosmic ray induced production mechanisms to the total emission are then reexamined. It is concluded that pulsars may account for a significant fraction of galactic gamma ray emission.

  9. DNA sequence analysis of X-ray induced Adh null mutations in Drosophila melanogaster

    SciTech Connect

    Mahmoud, J.; Fossett, N.G.; Arbour-Reily, P.; McDaniel, M.; Tucker, A.; Chang, S.H.; Lee, W.R. )

    1991-01-01

    The mutational spectrum for 28 X-ray induced mutations and 2 spontaneous mutations, previously determined by genetic and cytogenetic methods, consisted of 20 multilocus deficiencies (19 induced and 1 spontaneous) and 10 intragenic mutations (9 induced and 1 spontaneous). One of the X-ray induced intragenic mutations was lost, and another was determined to be a recombinant with the allele used in the recovery scheme. The DNA sequence of two X-ray induced intragenic mutations has been published. This paper reports the results of DNA sequence analysis of the remaining intragenic mutations and a summary of the X-ray induced mutational spectrum. The combination of DNA sequence analysis with genetic complementation analysis shows a continuous distribution in size of deletions rather than two different types of mutations consisting of deletions and point mutations'. Sequencing is shown to be essential for detecting intragenic deletions. Of particular importance for future studies is the observation that all of the intragenic deletions consist of a direct repeat adjacent to the breakpoint with one of the repeats deleted.

  10. Are there x-ray induced signature mutations in human cells?

    SciTech Connect

    Nelson, S.L.; Giver, C.R.; Grosovsky, A.J.

    1994-12-31

    Investigations of mutational spectra generally have two primary objectives: identification of mutagen specific hallmark mutations, and insight into mutagenic mechanisms. In order to address these two crucial issues we have examined the spectrum of 116 x-ray induced, and 78 spontaneous, HPRT{sup -} mutants derived from the human B lymphoblastoid cell line TK6. Multiplex PCR analysis demonstrated that the overall representation of large deletions was not significantly different in the 2 spectra, although highly significant differences were observed for specific deletion types. Total gene deletions represented 41/78 (.53) of x-ray induced, but only 7/43 (.16) of spontaneous, deletions (p < .0001). In contrast, 5{prime} terminal deletions were significantly more common among spontaneous (17/43, .40) than x-ray induced (13/78, .17) large deletions (p=.0079). Chromosomal scale investigation of x-ray induced and spontaneous hprt total deletion mutants was also performed using cytogenetic examination, and X-linked PCR probes. The types of point mutations induced by x-ray exposure were very diverse, including all classes of transitions and transversions, tandem base substitutions, frameshifts, and a deletion/insertion compound mutation. Compared to spontaneous data, radiation induced point mutations exhibited a significantly reduced number of transitions, and an increased representation of small deletions. Small deletions were uniformly surrounded by direct sequence repeats. The distribution of x-ray induced point mutations was characterized by a cluster of 8 mutants within a 30 base region of exon 8. Thirteen HPRT{sup -} point mutants exhibited aberrant splicing, 4 of which were attributable to coding sequence alterations within exons 4 and 8. These results suggest that it may be possible to identify hallmark mutations associated with x-ray exposure of human cells.

  11. Reciprocal food sharing in the vampire bat

    NASA Astrophysics Data System (ADS)

    Wilkinson, Gerald S.

    1984-03-01

    Behavioural reciprocity can be evolutionarily stable1-3. Initial increase in frequency depends, however, on reciprocal altruists interacting predominantly with other reciprocal altruists either by associating within kin groups or by having sufficient memory to recognize and not aid nonreciprocators. Theory thus suggests that reciprocity should evolve more easily among animals which live in kin groups. Data are available separating reciprocity from nepotism only for unrelated nonhuman animals4. Here, I show that food sharing by regurgitation of blood among wild vampire bats (Desmodus rotundus) depends equally and independently on degree of relatedness and an index of opportunity for recipro cation. That reciprocity operates within groups containing both kin and nonkin is supported further with data on the availability of blood-sharing occasions, estimates of the economics of shar ing blood, and experiments which show that unrelated bats will reciprocally exchange blood in captivity.

  12. Reciprocal uniparental disomy in yeast

    PubMed Central

    Andersen, Sabrina L.; Petes, Thomas D.

    2012-01-01

    In the diploid cells of most organisms, including humans, each chromosome is usually distinguishable from its partner homolog by multiple single-nucleotide polymorphisms. One common type of genetic alteration observed in tumor cells is uniparental disomy (UPD), in which a pair of homologous chromosomes are derived from a single parent, resulting in loss of heterozygosity for all single-nucleotide polymorphisms while maintaining diploidy. Somatic UPD events are usually explained as reflecting two consecutive nondisjunction events. Here we report a previously undescribed mode of chromosome segregation in Saccharomyces cerevisiae in which one cell division produces daughter cells with reciprocal UPD for the same pair of chromosomes without an aneuploid intermediate. One pair of sister chromatids is segregated into one daughter cell and the other pair is segregated into the other daughter cell, mimicking a meiotic chromosome segregation pattern. We term this process “reciprocal uniparental disomy.” PMID:22665764

  13. An Autonomously Reciprocating Transmembrane Nanoactuator.

    PubMed

    Watson, Matthew A; Cockroft, Scott L

    2016-01-22

    Biological molecular machines operate far from equilibrium by coupling chemical potential to repeated cycles of dissipative nanomechanical motion. This principle has been exploited in supramolecular systems that exhibit true machine behavior in solution and on surfaces. However, designed membrane-spanning assemblies developed to date have been limited to simple switches or stochastic shuttles, and true machine behavior has remained elusive. Herein, we present a transmembrane nanoactuator that turns over chemical fuel to drive autonomous reciprocating (back-and-forth) nanomechanical motion. Ratcheted reciprocating motion of a DNA/PEG copolymer threaded through a single α-hemolysin pore was induced by a combination of DNA strand displacement processes and enzyme-catalyzed reactions. Ion-current recordings revealed saw-tooth patterns, indicating that the assemblies operated in autonomous, asymmetric cycles of conformational change at rates of up to one cycle per minute. PMID:26661295

  14. Piston reciprocating compressed air engine

    SciTech Connect

    Cestero, L.G.

    1987-03-24

    A compressed air engine is described comprising: (a). a reservoir of compressed air, (b). two power cylinders each containing a reciprocating piston connected to a crankshaft and flywheel, (c). a transfer cylinder which communicates with each power cylinder and the reservoir, and contains a reciprocating piston connected to the crankshaft, (d). valve means controlled by rotation of the crankshaft for supplying compressed air from the reservoir to each power cylinder and for exhausting compressed air from each power cylinder to the transfer cylinder, (e). valve means controlled by rotation of the crankshaft for supplying from the transfer cylinder to the reservoir compressed air supplied to the transfer cylinder on the exhaust strokes of the pistons of the power cylinders, and (f). an externally powered fan for assisting the exhaust of compressed air from each power cylinder to the transfer cylinder and from there to the compressed air reservoir.

  15. Best compression: Reciprocating or rotary?

    SciTech Connect

    Cahill, C.

    1997-07-01

    A compressor is a device used to increase the pressure of a compressible fluid. The inlet pressure can vary from a deep vacuum to a high positive pressure. The discharge pressure can range from subatmospheric levels to tens of thousands of pounds per square inch. Compressors come in numerous forms, but for oilfield applications there are two primary types, reciprocating and rotary. Both reciprocating and rotary compressors are grouped in the intermittent mode of compression. Intermittent is cyclic in nature, in that a specific quantity of gas is ingested by the compressor, acted upon and discharged before the cycle is repeated. Reciprocating compression is the most common form of compression used for oilfield applications. Rotary screw compressors have a long history but are relative newcomers to oilfield applications. The rotary screw compressor-technically a helical rotor compressor-dates back to 1878. That was when the first rotary screw was manufactured for the purpose of compressing air. Today thousands of rotary screw compression packages are being used throughout the world to compress natural gas.

  16. Evolution of cooperation without reciprocity

    NASA Astrophysics Data System (ADS)

    Riolo, Rick L.; Cohen, Michael D.; Axelrod, Robert

    2001-11-01

    A long-standing problem in biological and social sciences is to understand the conditions required for the emergence and maintenance of cooperation in evolving populations. For many situations, kin selection is an adequate explanation, although kin-recognition may still be a problem. Explanations of cooperation between non-kin include continuing interactions that provide a shadow of the future (that is, the expectation of an ongoing relationship) that can sustain reciprocity, possibly supported by mechanisms to bias interactions such as embedding the agents in a two-dimensional space or other context-preserving networks. Another explanation, indirect reciprocity, applies when benevolence to one agent increases the chance of receiving help from others. Here we use computer simulations to show that cooperation can arise when agents donate to others who are sufficiently similar to themselves in some arbitrary characteristic. Such a characteristic, or `tag', can be a marking, display, or other observable trait. Tag-based donation can lead to the emergence of cooperation among agents who have only rudimentary ability to detect environmental signals and, unlike models of direct or indirect reciprocity, no memory of past encounters is required.

  17. Imperfect information facilitates the evolution of reciprocity.

    PubMed

    Kurokawa, Shun

    2016-06-01

    The existence of cooperation demands explanation since cooperation is costly to the actor. Reciprocity has long been regarded as a potential explanatory mechanism for the existence of cooperation. Reciprocity is a mechanism wherein a cooperator responds to an opponent's behavior by switching his/her own behavior. Hence, a possible problematic case relevant to the theory of reciprocity evolution arises when the mechanism is such that the information regarding an opponent's behavior is imperfect. Although it has been confirmed also by previous theoretical studies that imperfect information interferes with the evolution of reciprocity, this argument is based on the assumption that there are no mistakes in behavior. And, a previous study presumed that it might be expected that when such mistakes occur, reciprocity can more readily evolve in the case of imperfect information than in the case of perfect information. The reason why the previous study considers so is that in the former case, reciprocators can miss defections incurred by other reciprocators' mistakes due to imperfect information, allowing cooperation to persist when such reciprocators meet. However, contrary to this expectation, the previous study has shown that even when mistakes occur, imperfect information interferes with the evolution of reciprocity. Nevertheless, the previous study assumed that payoffs are linear (i.e., that the effect of behavior is additive and there are no synergetic effects). In this study, we revisited the same problem but removed the assumption that payoffs are linear. We used evolutionarily stable strategy analysis to compare the condition for reciprocity to evolve when mistakes occur and information is imperfect with the condition for reciprocity to evolve when mistakes occur and information is perfect. Our study revealed that when payoffs are not linear, imperfect information can facilitate the evolution of reciprocity when mistakes occur; while when payoffs are linear

  18. Cosmic ray-induced soft errors in static MOS memory cells

    NASA Technical Reports Server (NTRS)

    Sivo, L. L.; Peden, J. C.; Brettschneider, M.; Price, W.; Pentecost, P.

    1979-01-01

    Previous analytical models were extended to predict cosmic ray-induced soft error rates in static MOS memory devices. The effect is due to ionization and can be introduced by high energy, heavy ion components of the galactic environment. The results indicate that the sensitivity of memory cells is directly related to the density of the particular MOS technology which determines the node capacitance values. Hence, CMOS is less sensitive than e.g., PMOS. In addition, static MOS memory cells are less sensitive than dynamic ones due to differences in the mechanisms of storing bits. The flip-flop of a static cell is inherently stable against cosmic ray-induced bit flips. Predicted error rates on a CMOS RAM and a PMOS shift register are in general agreement with previous spacecraft flight data.

  19. Cosmic-ray-induced background intercomparison with actively shielded HPGe detectors at underground locations

    NASA Astrophysics Data System (ADS)

    Szücs, T.; Bemmerer, D.; Reinhardt, T. P.; Schmidt, K.; Takács, M. P.; Wagner, A.; Wagner, L.; Weinberger, D.; Zuber, K.

    2015-03-01

    The main background above 3MeV for in-beam nuclear astrophysics studies with -ray detectors is caused by cosmic-ray-induced secondaries. The two commonly used suppression methods, active and passive shielding, against this kind of background were formerly considered only as alternatives in nuclear astrophysics experiments. In this work the study of the effects of active shielding against cosmic-ray-induced events at a medium deep location is performed. Background spectra were recorded with two actively shielded HPGe detectors. The experiment was located at 148m below the surface of the Earth in the Reiche Zeche mine in Freiberg, Germany. The results are compared to data with the same detectors at the Earth's surface, and at depths of 45m and 1400m, respectively.

  20. Ultraintense X-Ray Induced Ionization, Dissociation, and Frustrated Absorption in Molecular Nitrogen

    SciTech Connect

    Hoener, M.; Fang, L.; Murphy, B.; Berrah, N.; Kornilov, O.; Gessner, O.; Pratt, S. T.; Kanter, E. P.; Guehr, M.; Bucksbaum, P. H.; Cryan, J.; Glownia, M.; McFarland, B.; Petrovic, V.; Blaga, C.; DiMauro, L.; Bostedt, C.; Bozek, J. D.; Coffee, R.; Messerschmidt, M.

    2010-06-25

    Sequential multiple photoionization of the prototypical molecule N{sub 2} is studied with femtosecond time resolution using the Linac Coherent Light Source (LCLS). A detailed picture of intense x-ray induced ionization and dissociation dynamics is revealed, including a molecular mechanism of frustrated absorption that suppresses the formation of high charge states at short pulse durations. The inverse scaling of the average target charge state with x-ray peak brightness has possible implications for single-pulse imaging applications.

  1. Ultraintense x-ray induced ionization, dissociation and frustrated absorption in molecular nitrogen.

    SciTech Connect

    Hoener, M.; Fang, L.; Kornilov, O.; Gessner, O.; Pratt, S. T.; Guhr, M.; Kanter, E. P.; Blaga, C.; Bostedt, C.; Bozek, J. D.; Bucksbaum, P. H.; Buth, C.; Chen, M.; Coffee, R.; Cryan, J.; DiMauro, L.; Glownia, M.; Hosler, E.; Kukk, E.; Leone, S. R.; McFarland, B.; Messerschmidt, M.; Murphy, B.; Petrovic, V.; Rolles, D.; Berrah, N.; Chemical Sciences and Engineering Division; Western Michigan Univ.; LBNL; Ohio State Univ.; Louisiana State Univ.; LLNL; Univ. of Turku; Univ. of California at Berkeley; Max Planck Advanced Study Group, CFEL; LCLS

    2010-06-23

    Sequential multiple photoionization of the prototypical molecule N2 is studied with femtosecond time resolution using the Linac Coherent Light Source (LCLS). A detailed picture of intense x-ray induced ionization and dissociation dynamics is revealed, including a molecular mechanism of frustrated absorption that suppresses the formation of high charge states at short pulse durations. The inverse scaling of the average target charge state with x-ray peak brightness has possible implications for single-pulse imaging applications.

  2. Directional excitation without breaking reciprocity

    NASA Astrophysics Data System (ADS)

    Ramezani, Hamidreza; Dubois, Marc; Wang, Yuan; Shen, Y. Ron; Zhang, Xiang

    2016-09-01

    We propose a mechanism for directional excitation without breaking reciprocity. This is achieved by embedding an impedance matched parity-time symmetric potential in a three-port system. The amplitude distribution within the gain and loss regions is strongly influenced by the direction of the incoming field. Consequently, the excitation of the third port is contingent on the direction of incidence while transmission in the main channel is immune. Our design improves the four-port directional coupler scheme, as there is no need to implement an anechoic termination to one of the ports.

  3. Towards a unified theory of reciprocity.

    PubMed

    Rosas, Alejandro

    2012-02-01

    In a unified theory of human reciprocity, the strong and weak forms are similar because neither is biologically altruistic and both require normative motivation to support cooperation. However, strong reciprocity is necessary to support cooperation in public goods games. It involves inflicting costs on defectors; and though the costs for punishers are recouped, recouping costs requires complex institutions that would not have emerged if weak reciprocity had been enough.

  4. Measurement of the energy dependence of X-ray-induced decomposition of potassium chlorate.

    PubMed

    Pravica, Michael; Bai, Ligang; Sneed, Daniel; Park, Changyong

    2013-03-21

    We report the first measurements of the X-ray induced decomposition of KClO3 as a function of energy in two experiments. KClO3 was pressurized to 3.5 GPa and irradiated with monochromatic synchrotron X-rays ranging in energy from 15 to 35 keV in 5 keV increments. A systematic increase in the decomposition rate as the energy was decreased was observed, which agrees with the 1/E(3) trend for the photoelectric process, except at the lowest energy studied. A second experiment was performed to access lower energies (10 and 12 keV) using a beryllium gasket; suggesting an apparent resonance near 15 keV or 0.83 Ǻ maximizing the chemical decomposition rate. A third experiment was performed using KIO3 to ascertain the anionic dependence of the decomposition rate, which was observed to be far slower than in KClO3, suggesting that the O-O distance is the critical factor in chemical reactions. These results will be important for more efficiently initiating chemical decomposition in materials using selected X-ray wavelengths that maximize decomposition to aid useful hard X-ray-induced chemistry and contribute understanding of the mechanism of X-ray-induced decomposition of the chlorates.

  5. Reciprocating motion of active deformable particles

    NASA Astrophysics Data System (ADS)

    Tarama, M.; Ohta, T.

    2016-05-01

    Reciprocating motion of an active deformable particle in a homogeneous medium is studied theoretically. For generality, we employ a simple model derived from symmetry considerations for the center-of-mass velocity and elliptical and triangular deformations in two dimensions. We carry out, for the first time, a systematic investigation of the reciprocating motion of a self-propelled particle. It is clarified that spontaneous breaking of the front-rear asymmetry is essential for the reciprocating motion. Moreover, two routes are found for the formation of the reciprocating motion. One is a bifurcation from a motionless stationary state. The other is destabilisation of an oscillatory rectilinear motion.

  6. Evolution of spite through indirect reciprocity.

    PubMed Central

    Johnstone, Rufus A.; Bshary, Redouan

    2004-01-01

    How can cooperation persist in the face of a temptation to 'cheat'? Several recent papers have suggested that the answer may lie in indirect reciprocity. Altruistic individuals may benefit by eliciting altruism from observers, rather than (as in direct reciprocity) from the recipient of the aid they provide. Here, we point out that indirect reciprocity need not always favour cooperation; by contrast, it may support spiteful behaviour, which is costly for the both actor and recipient. Existing theory suggests spite is unlikely to persist, but we demonstrate that it may do so when spiteful individuals are less likely to incur aggression from observers (a negative form of indirect reciprocity). PMID:15347514

  7. Indirect reciprocity with trinary reputations.

    PubMed

    Tanabe, Shoma; Suzuki, Hideyuki; Masuda, Naoki

    2013-01-21

    Indirect reciprocity is a reputation-based mechanism for cooperation in social dilemma situations when individuals do not repeatedly meet. The conditions under which cooperation based on indirect reciprocity occurs have been examined in great details. Most previous theoretical analysis assumed for mathematical tractability that an individual possesses a binary reputation value, i.e., good or bad, which depends on their past actions and other factors. However, in real situations, reputations of individuals may be multiple valued. Another puzzling discrepancy between the theory and experiments is the status of the so-called image scoring, in which cooperation and defection are judged to be good and bad, respectively, independent of other factors. Such an assessment rule is found in behavioral experiments, whereas it is known to be unstable in theory. In the present study, we fill both gaps by analyzing a trinary reputation model. By an exhaustive search, we identify all the cooperative and stable equilibria composed of a homogeneous population or a heterogeneous population containing two types of players. Some results derived for the trinary reputation model are direct extensions of those for the binary model. However, we find that the trinary model allows cooperation under image scoring under some mild conditions.

  8. Indirect reciprocity with trinary reputations.

    PubMed

    Tanabe, Shoma; Suzuki, Hideyuki; Masuda, Naoki

    2013-01-21

    Indirect reciprocity is a reputation-based mechanism for cooperation in social dilemma situations when individuals do not repeatedly meet. The conditions under which cooperation based on indirect reciprocity occurs have been examined in great details. Most previous theoretical analysis assumed for mathematical tractability that an individual possesses a binary reputation value, i.e., good or bad, which depends on their past actions and other factors. However, in real situations, reputations of individuals may be multiple valued. Another puzzling discrepancy between the theory and experiments is the status of the so-called image scoring, in which cooperation and defection are judged to be good and bad, respectively, independent of other factors. Such an assessment rule is found in behavioral experiments, whereas it is known to be unstable in theory. In the present study, we fill both gaps by analyzing a trinary reputation model. By an exhaustive search, we identify all the cooperative and stable equilibria composed of a homogeneous population or a heterogeneous population containing two types of players. Some results derived for the trinary reputation model are direct extensions of those for the binary model. However, we find that the trinary model allows cooperation under image scoring under some mild conditions. PMID:23123557

  9. The New York Schools Insurance Reciprocal.

    ERIC Educational Resources Information Center

    Lapetina, Alison J.

    1990-01-01

    Describes the New York Schools Insurance Reciprocal (NYSIR), which provides both property and liability coverage for school districts. A reciprocal is wholly owned by those insured. NYSIR insures 55 school district subscribers, providing a service that specifically accommodates school district needs and saves them money. (MLF)

  10. Reciprocal Tutoring: Design with Cognitive Load Sharing

    ERIC Educational Resources Information Center

    Chou, Chih-Yueh; Chan, Tak-Wai

    2016-01-01

    "Reciprocal tutoring," as reported in "Exploring the design of computer supports for reciprocal tutoring" (Chan and Chou 1997), has extended the meaning and scope of "intelligent tutoring" originally implemented in stand alone computers. This research is a follow-up to our studies on a "learning companion…

  11. The Effects of Reciprocal Teaching on Comprehension.

    ERIC Educational Resources Information Center

    Frances, Shannon M.; Eckart, Joyce A.

    An action research project investigated the effect of reciprocal teaching instruction and use on the comprehension of seventh-grade general English students. Reciprocal teaching is a form of dialogue structured around four skills--question generation, summarization, clarification, and prediction. These techniques are used in small group…

  12. Education, Gift and Reciprocity: A Preliminary Discussion

    ERIC Educational Resources Information Center

    Sabourin, Eric

    2013-01-01

    This paper analyzes the importance and role of the reciprocity relationship in education. It presents a review on the mobilization of the principle of reciprocity--in the anthropological but also sociological and economic senses--in educational processes, especially in adult education. The study is divided into three parts. The first part analyzes…

  13. An Introduction to the Onsager Reciprocal Relations

    ERIC Educational Resources Information Center

    Monroe, Charles W.; Newman, John

    2007-01-01

    The Onsager reciprocal relations are essential to multicomponent transport theory. A discussion of the principles that should be used to derive flux laws for coupled diffusion is presented here. Fluctuation theory is employed to determine the reciprocal relation for transport coefficients that characterize coupled mass and heat transfer in binary…

  14. Reflexive and Reciprocal Elements in Ixil.

    ERIC Educational Resources Information Center

    Ayres, Glenn

    1990-01-01

    Reflexives and reciprocals in Ixil, a Mayan language of Guatemala, appear to have features that distinguish them from reflexives surveyed in typological studies such as Faltz (1985) and Geniusiene (1987). Third person reflexives and reciprocals seem to have the form of a possessed noun optionally followed by a possessor NP. Moreover, reflexives…

  15. Principles of femtosecond X-ray/optical cross-correlation with X-ray induced transient optical reflectivity in solids

    SciTech Connect

    Eckert, S. E-mail: martin.beye@helmholtz-berlin.de; Beye, M. E-mail: martin.beye@helmholtz-berlin.de; Pietzsch, A.; Quevedo, W.; Hantschmann, M.; Ochmann, M.; Huse, N.; Ross, M.; Khalil, M.; Minitti, M. P.; Turner, J. J.; Moeller, S. P.; Schlotter, W. F.; Dakovski, G. L.; Föhlisch, A.

    2015-02-09

    The discovery of ultrafast X-ray induced optical reflectivity changes enabled the development of X-ray/optical cross correlation techniques at X-ray free electron lasers worldwide. We have now linked through experiment and theory the fundamental excitation and relaxation steps with the transient optical properties in finite solid samples. Therefore, we gain a thorough interpretation and an optimized detection scheme of X-ray induced changes to the refractive index and the X-ray/optical cross correlation response.

  16. X-ray Methods in High-Intensity Discharges and Metal-Halide Lamps: X-ray Induced Fluorescence

    SciTech Connect

    Curry, John J.; Lapatovich, Walter P.; Henins, Albert

    2011-12-09

    We describe the use of x-ray induced fluorescence to study metal-halide high-intensity discharge lamps and to measure equilibrium vapor pressures of metal-halide salts. The physical principles of metal-halide lamps, relevant aspects of x-ray-atom interactions, the experimental method using synchrotron radiation, and x-ray induced fluorescence measurements relevant to metal-halide lamps are covered.

  17. Multiplicative noise enhances spatial reciprocity

    NASA Astrophysics Data System (ADS)

    Yao, Yao; Chen, Shen-Shen

    2014-11-01

    Recent research has identified the heterogeneity as crucial for the evolution of cooperation in spatial population. However, the influence of heterogeneous noise is still lacking. Inspired by this interesting question, in this work, we try to incorporate heterogeneous noise into the evaluation of utility, where only a proportion of population possesses noise, whose range can also be tuned. We find that increasing heterogeneous noise monotonously promotes cooperation and even translates the full defection phase (of the homogeneous version) into the complete cooperation phase. Moreover, the promotion effect of this mechanism can be attributed to the leading role of cooperators who have the heterogeneous noise. These type of cooperators can attract more agents penetrating into the robust cooperator clusters, which is beyond the text of traditional spatial reciprocity. We hope that our work may shed light on the understanding of the cooperative behavior in the society.

  18. Direct nano-scale patterning of Ag films using hard X-ray induced oxidation.

    PubMed

    Kim, Jae Myung; Lee, Su Yong; Kang, Hyon Chol; Noh, Do Young

    2015-01-01

    The morphological change of silver nano-particles (AgNPs) exposed to an intense synchrotron X-ray beam was investigated for the purpose of direct nano-scale patterning of metal thin films. AgNPs irradiated by hard X-rays in oxygen ambient were oxidized and migrated out of the illuminated region. The observed X-ray induced oxidation was utilized to fabricate nano-scale metal line patterns using sectioned WSi2/Si multilayers as masks. Lines with a width as small as 21 nm were successfully fabricated on Ag films on silicon nitride. Au/Ag nano-lines were also fabricated using the proposed method.

  19. Influence of caffeine on X-ray-induced killing and mutation in V79 cells

    SciTech Connect

    Bhattacharjee, S.B.; Bhattacharyya, N.; Chatterjee, S.

    1987-02-01

    Effects produced by caffeine on X-irradiated Chinese hamster V79 cells depended on the growth conditions of the cells. For exponentially growing cells, nontoxic concentrations of caffeine decreased the shoulder width from the survival curve, but the slope remained unchanged. The yield of mutants under the same conditions also remained unaffected. In case of density-inhibited cells, delaying trypsinization for 24 h after X irradiation increased the survival and decreased the yield of mutants. The presence of caffeine during this incubation period inhibited such recovery and significantly increased the yield of X-ray-induced mutants.

  20. X-ray-induced shortwave infrared biomedical imaging using rare-earth nanoprobes.

    PubMed

    Naczynski, Dominik Jan; Sun, Conroy; Türkcan, Silvan; Jenkins, Cesare; Koh, Ai Leen; Ikeda, Debra; Pratx, Guillem; Xing, Lei

    2015-01-14

    Shortwave infrared (SWIR or NIR-II) light provides significant advantages for imaging biological structures due to reduced autofluorescence and photon scattering. Here, we report on the development of rare-earth nanoprobes that exhibit SWIR luminescence following X-ray irradiation. We demonstrate the ability of X-ray-induced SWIR luminescence (X-IR) to monitor biodistribution and map lymphatic drainage. Our results indicate X-IR imaging is a promising new modality for preclinical applications and has potential for dual-modality molecular disease imaging.

  1. Constraining X-ray-Induced Photoevaporation of Protoplanetary Disks Orbiting Low-Mass Stars

    NASA Astrophysics Data System (ADS)

    Punzi, Kristina M.; Kastner, Joel H.; Rodriguez, David; Principe, David A.; Vican, Laura

    2016-01-01

    Low-mass, pre-main sequence stars possess intense high-energy radiation fields as a result of their strong stellar magnetic activity. This stellar UV and X-ray radiation may have a profound impact on the lifetimes of protoplanetary disks. We aim to constrain the X-ray-induced photoevaporation rates of protoplanetary disks orbiting low-mass stars by analyzing serendipitous XMM-Newton and Chandra X-ray observations of candidate nearby (D < 100 pc), young (age < 100 Myr) M stars identified in the GALEX Nearby Young-Star Survey (GALNYSS).

  2. X-ray-Induced Shortwave Infrared Biomedical Imaging Using Rare-Earth Nanoprobes

    PubMed Central

    2015-01-01

    Shortwave infrared (SWIR or NIR-II) light provides significant advantages for imaging biological structures due to reduced autofluorescence and photon scattering. Here, we report on the development of rare-earth nanoprobes that exhibit SWIR luminescence following X-ray irradiation. We demonstrate the ability of X-ray-induced SWIR luminescence (X-IR) to monitor biodistribution and map lymphatic drainage. Our results indicate X-IR imaging is a promising new modality for preclinical applications and has potential for dual-modality molecular disease imaging. PMID:25485705

  3. X-ray Induced Effects on Photocurrents in Amorphous Se Films

    NASA Astrophysics Data System (ADS)

    Shimakawa, Koichi; Fukami, Kenji; Kishi, Hiroki; Belev, George; Kasap, Safa

    2007-03-01

    Amorphous selenium (a-Se) is one of the X-ray photoconductors that is available for use in recently developed direct conversion flat panel X-ray image detectors for medical imaging. To obtain a better understanding of trapping and recombination effects in a-Se, we have studied light and X-ray induced photocurrents in a-Se films. The residual photocurrent, after X-ray exposure, decreases in sandwich cells whereas it increases in coplanar cells. These effects are recovered over a time scale of hours. We show that the results can be interpreted by using valence alternation pair (VAP) type charged defects.

  4. Soft X-ray induced decomposition of phenylalanine and tyrosine: Acomparative study

    SciTech Connect

    Zubavichus, Y.; Zharnikov, M.; Shaporenko, A.; Fuchs, O.; Weinhart, L.; Heske, C.; Umbach, E.; Denlinger, J.D.; Grunze, M.

    2003-11-19

    The pristine state and soft X-ray induced decomposition of two aromatic amino acids, viz. phenylalanine and tyrosine, have been studied by means of XPS and NEXAFS. The spectroscopic data on the radiation decomposition have been supplemented by a mass-spectral analysis of desorbed species in the residual gas. Despite very similar chemical structures, the two amino acids show a drastically different behavior towards ionizing radiation: phenylalanine degrades very quickly whereas tyrosine shows a prominent stability against radiation damage. Reasons for this difference are discussed in relation to radical-mediated reactions responsible for the decomposition.

  5. Gamma ray induced thermoluminescence properties of Eu{sup 3+} doped SnO{sub 2} phosphor

    SciTech Connect

    Chowdhury, M.; Sharma, S.K.; Lochab, S.P.

    2015-10-15

    Highlights: • TL properties of SnO{sub 2}:Eu{sup 3+} were reported upon γ-ray irradiation. • Effect of doping, irradiation dose and heating rate on TL properties were studied in detail. • The kinetic parameters associated with TL were calculated for first time in SnO{sub 2}:Eu{sup 3+}. • Existence of second-order kinetics indicates the occurrence of retrapping phenomena. • Retrapping of electrons at deep traps occurred due to thermal energy stimulation. - Abstract: This paper reports the thermoluminescence properties of Eu{sup 3+} doped SnO{sub 2} phosphors synthesized by combustion method. The thermoluminescence (TL) studies were carried out after irradiating the sample by γ-rays in the dose range 100 Gy to 1 KGy. The glow curves of γ-irradiated phosphors were resolved into two peaks, one centred at 116 °C and other at 300 °C. Intensity of the glow peak increases linearly in the studied dose range of γ-rays. Kinetic parameters such as order of kinetics, trap depth and frequency factor associated with the glow peak were calculated by various glow curve methods.

  6. Reciprocity and Ethical Tuberculosis Treatment and Control.

    PubMed

    Silva, Diego S; Dawson, Angus; Upshur, Ross E G

    2016-03-01

    This paper explores the notion of reciprocity in the context of active pulmonary and laryngeal tuberculosis (TB) treatment and related control policies and practices. We seek to do three things: First, we sketch the background to contemporary global TB care and suggest that poverty is a key feature when considering the treatment of TB patients. We use two examples from TB care to explore the role of reciprocity: isolation and the use of novel TB drugs. Second, we explore alternative means of justifying the use of reciprocity through appeal to different moral and political theoretical traditions (i.e., virtue ethics, deontology, and consequentialism). We suggest that each theory can be used to provide reasons to take reciprocity seriously as an independent moral concept, despite any other differences. Third, we explore general meanings and uses of the concept of reciprocity, with the primary intention of demonstrating that it cannot be simply reduced to other more frequently invoked moral concepts such as beneficence or justice. We argue that reciprocity can function as a mid-level principle in public health, and generally, captures a core social obligation arising once an individual or group is burdened as a result of acting for the benefit of others (even if they derive a benefit themselves). We conclude that while more needs to be explored in relation to the theoretical justification and application of reciprocity, sufficient arguments can be made for it to be taken more seriously as a key principle within public health ethics and bioethics more generally. PMID:26797512

  7. Reciprocity and Ethical Tuberculosis Treatment and Control.

    PubMed

    Silva, Diego S; Dawson, Angus; Upshur, Ross E G

    2016-03-01

    This paper explores the notion of reciprocity in the context of active pulmonary and laryngeal tuberculosis (TB) treatment and related control policies and practices. We seek to do three things: First, we sketch the background to contemporary global TB care and suggest that poverty is a key feature when considering the treatment of TB patients. We use two examples from TB care to explore the role of reciprocity: isolation and the use of novel TB drugs. Second, we explore alternative means of justifying the use of reciprocity through appeal to different moral and political theoretical traditions (i.e., virtue ethics, deontology, and consequentialism). We suggest that each theory can be used to provide reasons to take reciprocity seriously as an independent moral concept, despite any other differences. Third, we explore general meanings and uses of the concept of reciprocity, with the primary intention of demonstrating that it cannot be simply reduced to other more frequently invoked moral concepts such as beneficence or justice. We argue that reciprocity can function as a mid-level principle in public health, and generally, captures a core social obligation arising once an individual or group is burdened as a result of acting for the benefit of others (even if they derive a benefit themselves). We conclude that while more needs to be explored in relation to the theoretical justification and application of reciprocity, sufficient arguments can be made for it to be taken more seriously as a key principle within public health ethics and bioethics more generally.

  8. Two distinct neural mechanisms underlying indirect reciprocity.

    PubMed

    Watanabe, Takamitsu; Takezawa, Masanori; Nakawake, Yo; Kunimatsu, Akira; Yamasue, Hidenori; Nakamura, Mitsuhiro; Miyashita, Yasushi; Masuda, Naoki

    2014-03-18

    Cooperation is a hallmark of human society. Humans often cooperate with strangers even if they will not meet each other again. This so-called indirect reciprocity enables large-scale cooperation among nonkin and can occur based on a reputation mechanism or as a succession of pay-it-forward behavior. Here, we provide the functional and anatomical neural evidence for two distinct mechanisms governing the two types of indirect reciprocity. Cooperation occurring as reputation-based reciprocity specifically recruited the precuneus, a region associated with self-centered cognition. During such cooperative behavior, the precuneus was functionally connected with the caudate, a region linking rewards to behavior. Furthermore, the precuneus of a cooperative subject had a strong resting-state functional connectivity (rsFC) with the caudate and a large gray matter volume. In contrast, pay-it-forward reciprocity recruited the anterior insula (AI), a brain region associated with affective empathy. The AI was functionally connected with the caudate during cooperation occurring as pay-it-forward reciprocity, and its gray matter volume and rsFC with the caudate predicted the tendency of such cooperation. The revealed difference is consistent with the existing results of evolutionary game theory: although reputation-based indirect reciprocity robustly evolves as a self-interested behavior in theory, pay-it-forward indirect reciprocity does not on its own. The present study provides neural mechanisms underlying indirect reciprocity and suggests that pay-it-forward reciprocity may not occur as myopic profit maximization but elicit emotional rewards.

  9. Two distinct neural mechanisms underlying indirect reciprocity

    PubMed Central

    Watanabe, Takamitsu; Takezawa, Masanori; Nakawake, Yo; Kunimatsu, Akira; Yamasue, Hidenori; Nakamura, Mitsuhiro; Miyashita, Yasushi; Masuda, Naoki

    2014-01-01

    Cooperation is a hallmark of human society. Humans often cooperate with strangers even if they will not meet each other again. This so-called indirect reciprocity enables large-scale cooperation among nonkin and can occur based on a reputation mechanism or as a succession of pay-it-forward behavior. Here, we provide the functional and anatomical neural evidence for two distinct mechanisms governing the two types of indirect reciprocity. Cooperation occurring as reputation-based reciprocity specifically recruited the precuneus, a region associated with self-centered cognition. During such cooperative behavior, the precuneus was functionally connected with the caudate, a region linking rewards to behavior. Furthermore, the precuneus of a cooperative subject had a strong resting-state functional connectivity (rsFC) with the caudate and a large gray matter volume. In contrast, pay-it-forward reciprocity recruited the anterior insula (AI), a brain region associated with affective empathy. The AI was functionally connected with the caudate during cooperation occurring as pay-it-forward reciprocity, and its gray matter volume and rsFC with the caudate predicted the tendency of such cooperation. The revealed difference is consistent with the existing results of evolutionary game theory: although reputation-based indirect reciprocity robustly evolves as a self-interested behavior in theory, pay-it-forward indirect reciprocity does not on its own. The present study provides neural mechanisms underlying indirect reciprocity and suggests that pay-it-forward reciprocity may not occur as myopic profit maximization but elicit emotional rewards. PMID:24591599

  10. ADVANCED RECIPROCATING COMPRESSION TECHNOLOGY (ARCT)

    SciTech Connect

    Danny M. Deffenbaugh; Klaus Brun; Ralph E. Harris; J. Pete Harrell; Robert J. Mckee; J. Jeffrey Moore; Steven J. Svedeman; Anthony J. Smalley; Eugene L. Broerman; Robert A Hart; Marybeth G. Nored; Ryan S. Gernentz; Shane P. Siebenaler

    2005-12-01

    The U.S. natural gas pipeline industry is facing the twin challenges of increased flexibility and capacity expansion. To meet these challenges, the industry requires improved choices in gas compression to address new construction and enhancement of the currently installed infrastructure. The current fleet of installed reciprocating compression is primarily slow-speed integral machines. Most new reciprocating compression is and will be large, high-speed separable units. The major challenges with the fleet of slow-speed integral machines are: limited flexibility and a large range in performance. In an attempt to increase flexibility, many operators are choosing to single-act cylinders, which are causing reduced reliability and integrity. While the best performing units in the fleet exhibit thermal efficiencies between 90% and 92%, the low performers are running down to 50% with the mean at about 80%. The major cause for this large disparity is due to installation losses in the pulsation control system. In the better performers, the losses are about evenly split between installation losses and valve losses. The major challenges for high-speed machines are: cylinder nozzle pulsations, mechanical vibrations due to cylinder stretch, short valve life, and low thermal performance. To shift nozzle pulsation to higher orders, nozzles are shortened, and to dampen the amplitudes, orifices are added. The shortened nozzles result in mechanical coupling with the cylinder, thereby, causing increased vibration due to the cylinder stretch mode. Valve life is even shorter than for slow speeds and can be on the order of a few months. The thermal efficiency is 10% to 15% lower than slow-speed equipment with the best performance in the 75% to 80% range. The goal of this advanced reciprocating compression program is to develop the technology for both high speed and low speed compression that will expand unit flexibility, increase thermal efficiency, and increase reliability and integrity

  11. Self-reciprocating radioisotope-powered cantilever

    NASA Astrophysics Data System (ADS)

    Li, Hui; Lal, Amit; Blanchard, James; Henderson, Douglass

    2002-07-01

    A reciprocating cantilever utilizing emitted charges from a millicurie radioisotope thin film is presented. The actuator realizes a direct collected-charge-to-motion conversion. The reciprocation is obtained by self-timed contact between the cantilever and the radioisotope source. A static model balancing the electrostatic and mechanical forces from an equivalent circuit leads to an analytical solution useful for device characterization. Measured reciprocating periods agree with predicted values from the analytical model. A scaling analysis shows that microscale arrays of such cantilevers provide an integrated sensor and actuator platform.

  12. Accurate analytical modelling of cosmic ray induced failure rates of power semiconductor devices

    NASA Astrophysics Data System (ADS)

    Bauer, Friedhelm D.

    2009-06-01

    A new, simple and efficient approach is presented to conduct estimations of the cosmic ray induced failure rate for high voltage silicon power devices early in the design phase. This allows combining common design issues such as device losses and safe operating area with the constraints imposed by the reliability to result in a better and overall more efficient design methodology. Starting from an experimental and theoretical background brought forth a few yeas ago [Kabza H et al. Cosmic radiation as a cause for power device failure and possible countermeasures. In: Proceedings of the sixth international symposium on power semiconductor devices and IC's, Davos, Switzerland; 1994. p. 9-12, Zeller HR. Cosmic ray induced breakdown in high voltage semiconductor devices, microscopic model and possible countermeasures. In: Proceedings of the sixth international symposium on power semiconductor devices and IC's, Davos, Switzerland; 1994. p. 339-40, and Matsuda H et al. Analysis of GTO failure mode during d.c. blocking. In: Proceedings of the sixth international symposium on power semiconductor devices and IC's, Davos, Switzerland; 1994. p. 221-5], an exact solution of the failure rate integral is derived and presented in a form which lends itself to be combined with the results available from commercial semiconductor simulation tools. Hence, failure rate integrals can be obtained with relative ease for realistic two- and even three-dimensional semiconductor geometries. Two case studies relating to IGBT cell design and planar junction termination layout demonstrate the purpose of the method.

  13. Reciprocating piston internal combustion engine

    SciTech Connect

    Hayashi, Y.

    1986-04-15

    A reciprocating piston internal combustion engine is described which consists of: a piston movably disposed within an engine cylinder, the piston having a top surface and a piston ring, the engine cylinder and the top surface of the piston defining a combustion chamber, the piston having first and second sections which are divided by a vertical plane containing an axis of a piston pin, the first section being formed with a major thrust surface and the second section being formed with a minor thrust surface; and means for thrusting the piston against a major thrust side wall of the cylinder before the piston reaches top dead center in the cylinder, the thrusting means comprising: means defining a space in the piston, the space communicating with the combustion chamber and being located in the piston second section; a movable member disposed within the space, the movable member being capable of being thrust in the direction of a minor thrust side wall of the cylinder by gas pressure within the combustion chamber and being arranged to thrust the piston ring against the minor thrust side wall when thrust by the gas pressure; and means for producing gas pressure within the combustion chamber such that the gas pressure enters the space at the compression stroke of the engine so that the movable member receives the gas pressure and is thrust toward the minor thrust side wall of the cylinder such that the piston is thrust against a major thrust side wall of the cylinder.

  14. Reciprocal engine with floating liner

    SciTech Connect

    Paul, M.A.; Paul, A.

    1989-06-27

    An internal combustion engine with a heat recovery system is described comprising: a cylinder with a cylinder wall; a piston with a piston head, the piston being reciprocally displaceable in the cylinder; a fuel injection means with fuel connected to the cylinder; and, an air intake passage and an exhaust passage connected to the cylinder, such that air is delivered to the cylinder, compressed by the piston, and fuel from the fuel injection means is delivered to the cylinder and combusted in a working chamber; wherein the heat recovery system includes an air-porous, heat-resistant tubular liner suspended in the cylinder and displaced from the wall of the cylinder, the piston having a deep groove with inner and outer walls in the head of the piston into which the liner is received when the piston is displaced compressing the air, the liner being spaced from the inner and outer walls of the groove such that three insulating zones are provided between combustion gases in the cylinder and the cylinder wall during displacement of the piston.

  15. An inquiry into relationship suicides and reciprocity.

    PubMed

    Davis, Mark S; Callanan, Valerie J; Lester, David; Haines, Janet

    2009-10-01

    Few theories on suicide have been grounded in the norm of reciprocity. There is literature on suicide, however, describing motivations such as retaliation and retreat which can be interpreted as modes of adaptation to the norm of reciprocity. We propose a reciprocity-based theory to explain suicides associated with relationship problems. Employing a content analysis of suicide notes, we tested the theory, finding evidence of exploitation, exploiter guilt, retaliation, and retreat as motives for committing relationship-based suicide. Reciprocity-based note writers were more likely to have used alcohol or drugs in the hours prior to committing suicide, and they were also more likely to have made their intentions known beforehand. Implications for future research as well as for suicide prevention are discussed.

  16. 78 FR 53792 - Draft Guidance for Reciprocity

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-08-30

    ... (Reciprocity).'' The document has been updated from the previous revision to include safety culture, security.... Brian J. McDermott, Director, Division of Materials Safety and State Agreements, Office of Federal...

  17. 30 CFR 57.13010 - Reciprocating-type air compressors.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Reciprocating-type air compressors. 57.13010... Air and Boilers § 57.13010 Reciprocating-type air compressors. (a) Reciprocating-type air compressors... than 25 percent. (b) However, this standard does not apply to reciprocating-type air compressors...

  18. 30 CFR 57.13010 - Reciprocating-type air compressors.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Reciprocating-type air compressors. 57.13010... Air and Boilers § 57.13010 Reciprocating-type air compressors. (a) Reciprocating-type air compressors... than 25 percent. (b) However, this standard does not apply to reciprocating-type air compressors...

  19. 30 CFR 57.13010 - Reciprocating-type air compressors.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Reciprocating-type air compressors. 57.13010... Air and Boilers § 57.13010 Reciprocating-type air compressors. (a) Reciprocating-type air compressors... than 25 percent. (b) However, this standard does not apply to reciprocating-type air compressors...

  20. 30 CFR 56.13010 - Reciprocating-type air compressors.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Reciprocating-type air compressors. 56.13010... and Boilers § 56.13010 Reciprocating-type air compressors. (a) Reciprocating-type air compressors... than 25 percent. (b) However, this standard does not apply to reciprocating-type air compressors...

  1. 30 CFR 57.13010 - Reciprocating-type air compressors.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Reciprocating-type air compressors. 57.13010... Air and Boilers § 57.13010 Reciprocating-type air compressors. (a) Reciprocating-type air compressors... than 25 percent. (b) However, this standard does not apply to reciprocating-type air compressors...

  2. 30 CFR 56.13010 - Reciprocating-type air compressors.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Reciprocating-type air compressors. 56.13010... and Boilers § 56.13010 Reciprocating-type air compressors. (a) Reciprocating-type air compressors... than 25 percent. (b) However, this standard does not apply to reciprocating-type air compressors...

  3. Effect of caffeine on the expression of a major X-ray induced protein in human tumor cells

    SciTech Connect

    Hughes, E.N.; Boothman, D.A. )

    1991-03-01

    We have examined the effect of caffeine on the concomitant processes of the repair of potentially lethal damage (PLD) and the synthesis of X-ray-induced proteins in the human malignant melanoma cell line, Ul-Mel. Caffeine administered at a dose of 5mM after X radiation not only inhibited PLD repair but also markedly reduced the level of XIP269, a major X-ray-induced protein whose expression has been shown to correlate with the capacity to repair PLD. The expression of the vast majority of other cellular proteins, including seven other X-ray-induced proteins, remained unchanged following caffeine treatment. A possible role for XIP269 in cell cycle delay following DNA damage by X irradiation is discussed.

  4. Note: Loading method of molecular fluorine using x-ray induced chemistry

    SciTech Connect

    Pravica, Michael Sneed, Daniel; White, Melanie; Wang, Yonggang

    2014-08-15

    We have successfully loaded molecular fluorine into a diamond anvil cell at high pressure using the synchrotron x-ray induced decomposition of perfluorohexane (C{sub 6}F{sub 14}). “White” x-ray radiation from the Advanced Photon Source was used to initiate the chemical decomposition of C{sub 6}F{sub 14}, which resulted in the in situ production of F{sub 2} as verified via Raman spectroscopy. Due to the toxic nature of fluorine, this method will offer significant advantages in the ability to easily load a relatively nontoxic and inert substance into a chamber (such as a diamond anvil cell) that, when sealed with other reactants and irradiate with hard x-rays (>7 keV), releases highly reactive and toxic fluorine into the sample/reaction chamber to enable novel chemical synthesis under isolated and/or extreme conditions.

  5. Measurement of equilibrium elemental vapor pressures using x-ray induced fluorescense.

    SciTech Connect

    Curry, J. J; Henins, A.; Estupinan, E. G.; Lapatovich, W. P.; Shastri, S. D.

    2011-04-29

    X-ray induced fluorescence is demonstrated as a novel and fast method for measuring vapor pressures at high temperatures and high pressures. As such, it is an excellent complement to the effusion method, which is limited to lower pressures. High-energy synchrotron radiation was used to measure the total densities of Dy in the equilibrium vapor over condensed DyI{sub 3} and Tm in the equilibrium vapor over condensed TmI{sub 3}. Corresponding vapor pressures were determined with measured vapor cell temperatures across a range of vapor pressures of nearly three orders of magnitude, from less than 10{sup 2} Pa to more than 10{sup 4} Pa. Individual data points were obtained in time periods ranging from 10 to 30 s each.

  6. PVDF measurement of soft x ray induced shock and filter debris impulse

    NASA Astrophysics Data System (ADS)

    Johnson, D. E.; Lee, L. M.; Hedemann, M. A.; Bauer, F.

    PVDF piezoelectric polymer shock stress sensors have been used to measure the shock and impulse generated by soft X-rays and by filter debris in the SATURN Plasma Radiation Source at Sandia National Laboratories, NM. SATURN was used to generate 30 to 40 kJ, 20-ns duration, line radiation at 2 to 3 keV. Fluence on samples was nominally 40, 200, and 400 kJ/m(sup 2) (1, 5, and 10 cal/cm(sup 2)). Measurements of X-ray induced material shock response exposing both aluminum and PMMA acrylic samples agree well with companion measurements made with single crystal X-cut quartz gauges. Time-of-flight, stress, and impulse produced by Kimfol (polycarbonate/aluminum) filter debris were also measured with the PVDF gauges.

  7. PVDF measurement of soft X-ray induced shock and filter debris impulse. [PVDF (polyvinylidene fluoride)

    SciTech Connect

    Johnson, D.E.; Lee, L.M. ); Hedemann, M.A. ); Bauer, F. )

    1993-01-01

    PVDF piezoelectric polymer shock stress sensors have been used to measure the shock and impulse generated by soft X-rays and by filter debris in the SATURN Plasma Radiation Source at Sandia National Laboratories, NM. SATURN was used to generate 30 to 40 kJ, 20-ns duration, line radiation at 2 to 3 keV. Fluence on samples was nominally 40, 200, and 400 kJ/m[sup 2] (1, 5, and 10 cal/cm[sup 2]). Measurements of X-ray induced material shock response exposing both aluminum and PMMA acrylic samples agree well with companion measurements made with single crystal X-cut quartz gauges. Time-of-flight, stress, and impulse produced by Kimfol (polycarbonate/aluminum) filter debris were also measured with the PVDF gauges.

  8. PVDF measurement of soft X-ray induced shock and filter debris impulse

    SciTech Connect

    Johnson, D.E.; Lee, L.M.; Hedemann, M.A.; Bauer, F.

    1993-07-01

    PVDF piezoelectric polymer shock stress sensors have been used to measure the shock and impulse generated by soft X-rays and by filter debris in the SATURN Plasma Radiation Source at Sandia National Laboratories, NM. SATURN was used to generate 30 to 40 kJ, 20-ns duration, line radiation at 2 to 3 keV. Fluence on samples was nominally 40, 200, and 400 kJ/m{sup 2} (1, 5, and 10 cal/cm{sup 2}). Measurements of X-ray induced material shock response exposing both aluminum and PMMA acrylic samples agree well with companion measurements made with single crystal X-cut quartz gauges. Time-of-flight, stress, and impulse produced by Kimfol (polycarbonate/aluminum) filter debris were also measured with the PVDF gauges.

  9. Advantages of passive detectors for the determination of the cosmic ray induced neutron environment.

    PubMed

    Hajek, M; Berger, T; Schöner, W; Vana, N

    2002-01-01

    Due to the pronounced energy dependence of the neutron quality factor, accurate assessment of the biologically relevant dose requires knowledge of the spectral neutron fluence rate. Bonner sphere spectrometers (BSSs) are the only instruments which provide a sufficient response over practically the whole energy range of the cosmic ray induced neutron component. Measurements in a 62 MeV proton beam at Paul Scherrer Institute, Switzerland, and in the CERN-EU high-energy reference field led to the assumption that conventional active devices for the detection of thermal neutrons inside the BSS, e.g. 6Lil(Eu) scintillators, also respond to charged particles when used in high-energy mixed radiation fields. The effects of these particles cannot be suppressed by amplitude discrimination and are subsequently misinterpreted as neutron radiation. In contrast, paired TLD-600 and TLD-700 thermoluminescence dosemeters allow the determination of a net thermal neutron signal.

  10. Cosmic-Ray-Induced Ship-Effect Neutron Measurements and Implications for Cargo Scanning at Borders

    SciTech Connect

    Kouzes, Richard T.; Ely, James H.; Seifert, Allen; Siciliano, Edward R.; Weier, Dennis R.; Windsor, Lindsay K.; Woodring, Mitchell L.; Borgardt, James D.; Buckley, Elise D.; Flumerfelt, Eric L.; Oliveri, Anna F.; Salvitti, Matthew

    2008-03-11

    Neutron measurements are used as part of the interdiction process for illicit nuclear materials at border crossings. Even though the natural neutron background is small, its variation can impact the sensitivity of detection systems. The natural background of neutrons that is observed in monitoring instruments arises almost entirely from cosmic ray induced cascades in the atmosphere and the surrounding environment. One significant source of variation in the observed neutron background is produced by the “ship effect” in large quantities of cargo that transit past detection instruments. This paper reports on results from measurements with typical monitoring equipment of ship effect neutrons in various materials. One new result is the “neutron shadow shielding” effect seen with some low neutron density materials.

  11. Induced Background in the Mars Observer Gamma-Ray Spectrometer

    NASA Technical Reports Server (NTRS)

    Boynton, William V.; Evans, Larry G.; Starr, Richard; Bruekner, Johnnes; Bailey, S. H.; Trombka, Jacob I.

    1997-01-01

    Gamma-Ray Spectrometers in space must necessarily work in an environment of a background of lines due to natural and cosmic-ray induced radioactivity and lines due to prompt emission following nuclear reactions caused by primary and secondary cosmic rays. The Gamma-Ray Spectrometer (GRS) on the Mar Observer mission has provided important data allowing one to estimate for future missions the extent of the background due to cosmic rays. These data will help in the design of instruments and in calculation of realistic background intensities that may effect the sensitivity of determining the intensity of lines of interest.

  12. Evolution of indirect reciprocity in groups of various sizes and comparison with direct reciprocity.

    PubMed

    Suzuki, Shinsuke; Akiyama, Eizo

    2007-04-01

    Recently many studies have investigated the evolution of indirect reciprocity through which cooperative action is returned by a third individual, e.g. individual A helped B and then receives help from C. Most studies on indirect reciprocity have presumed that only two individuals take part in a single interaction (group), e.g. A helps B and C helps A. In this paper, we investigate the evolution of indirect reciprocity when more than two individuals take part in a single group, and compare the result with direct reciprocity through which cooperative action is directly returned by the recipient. Our analyses show the following. In the population with discriminating cooperators and unconditional defectors, whether implementation error is included or not, (i) both strategies are evolutionarily stable and the evolution of indirect reciprocity becomes more difficult as group size increases, and (ii) the condition for the evolution of indirect reciprocity under standing reputation criterion where the third individuals distinguish between justified and unjustified defections is more relaxed than that under image scoring reputation criterion in which the third individuals do not distinguish with. Furthermore, in the population that also includes unconditional cooperators, (iii) in the presence of errors in implementation, the discriminating strategy is evolutionarily stable not only under standing but also under image scoring if group size is larger than two. Finally, (iv) in the absence of errors in implementation, the condition for the evolution of direct reciprocity is equivalent to that for the evolution of indirect reciprocity under standing, and, in the presence of errors, the condition for the evolution of direct reciprocity is very close to that for the evolution of indirect reciprocity under image scoring.

  13. Three-person game facilitates indirect reciprocity under image scoring.

    PubMed

    Suzuki, Shinsuke; Akiyama, Eizo

    2007-11-01

    Reputation building plays an important role in the evolution of reciprocal altruism when the same individuals do not interact repeatedly because, by referring to reputation, a reciprocator can know which partners are cooperative and can reciprocate with a cooperator. This reciprocity based on reputation is called indirect reciprocity. Previous studies of indirect reciprocity have focused only on two-person games in which only two individuals participate in a single interaction, and have claimed that indirectly reciprocal cooperation cannot be established under image scoring reputation criterion where the reputation of an individual who has cooperated (defected) becomes good (bad). In this study, we specifically examine three-person games, and reveal that indirectly reciprocal cooperation can be formed and maintained stably, even under image scoring, by a nucleus shield mechanism. In the nucleus shield, reciprocators are a shield that keeps out unconditional defectors, whereas unconditional cooperators are the backbone of cooperation that retains a good reputation among the population.

  14. Isochronal annealing study of X-ray induced defects in single- and double-walled carbon nanotubes

    SciTech Connect

    Murakami, Toshiya; Yamamoto, Yuki; Itoh, Chihiro; Kisoda, Kenji

    2013-09-21

    X-ray induced defects in single-walled (SWCNTs) and double-walled carbon nanotubes (DWCNTs) were characterized by Raman scattering spectroscopy. Frenkel defects, interstitial-vacancy pairs, were revealed to form in both SWCNTs and DWCNTs after X-ray irradiation because these defects were entirely healed by thermal annealing. In order to clarify the structure of the X-ray induced defect in SWCNT and DWCNT, isochronal-annealing experiments were performed on the irradiated samples and the activation energy for defect healing was estimated. The intensity of D band (defect induced band) on Raman spectra was used as a measure of the density of X-ray induced defects. The experimental results were in good agreement with the simulated values using second order reaction model, which indicated that the defect healing was determined by the migration energy of interstitials on the carbon layer. We also found that the activation energy for defect healing of SWCNT and DWCNT were around 0.5 eV and 0.32 eV, respectively. The X-ray induced defects in SWCNTs were more stable than those in DWCNTs. Compared these estimated activation energies to previous theoretical reports, we concluded that bridge and/or dumbbell interstitials are formed in both SWCNT and DWCNT by X-ray irradiation.

  15. Measuring and making decisions for social reciprocity.

    PubMed

    Solanas, Antonio; Leiva, David; Sierra, Vicenta; Salafranca, Lluís

    2009-08-01

    Social reciprocity may explain certain emerging psychological processes likely to be founded on dyadic relations. Although indexes and statistics have been proposed to measure and make statistical decisions regarding social reciprocity in groups, these tools were generally developed to identify association patterns rather than to quantify the discrepancies between what each individual addresses to his or her partners and what is received from those partners in return. Additionally, social researchers' interest extends beyond measuring groups at the global level because dyadic and individual measurements are also necessary for proper descriptions of social interactions. This study is concerned with a new statistic for measuring social reciprocity at the global level and with decomposing that statistic in order to identify which dyads and individuals account for a significant part of asymmetry in social interactions. In addition to a set of indexes, some exact analytical results are derived, and a way of making statistical decisions is proposed.

  16. Theory of reciprocating contact for viscoelastic solids

    NASA Astrophysics Data System (ADS)

    Putignano, Carmine; Carbone, Giuseppe; Dini, Daniele

    2016-04-01

    A theory of reciprocating contacts for linear viscoelastic materials is presented. Results are discussed for the case of a rigid sphere sinusoidally driven in sliding contact with a viscoelastic half-space. Depending on the size of the contact, the frequency and amplitude of the reciprocating motion, and on the relaxation time of the viscoelastic body, we establish that the contact behavior may range from the steady-state viscoelastic solution, in which traction forces always oppose the direction of the sliding rigid punch, to a more elaborate trend, which is due to the strong interaction between different regions of the path covered during the reciprocating motion. Practical implications span a number of applications, ranging from seismic engineering to biotechnology.

  17. Gauge invariance and reciprocity in quantum mechanics

    SciTech Connect

    Leung, P. T.; Young, K.

    2010-03-15

    Reciprocity in wave propagation usually refers to the symmetry of the Green's function under the interchange of the source and the observer coordinates, but this condition is not gauge invariant in quantum mechanics, a problem that is particularly significant in the presence of a vector potential. Several possible alternative criteria are given and analyzed with reference to different examples with nonzero magnetic fields and/or vector potentials, including the case of a multiply connected spatial domain. It is shown that the appropriate reciprocity criterion allows for specific phase factors separable into functions of the source and observer coordinates and that this condition is robust with respect to the addition of any scalar potential. In the Aharonov-Bohm effect, reciprocity beyond monoenergetic experiments holds only because of subsidiary conditions satisfied in actual experiments: the test charge is in units of e and the flux is produced by a condensate of particles with charge 2e.

  18. Reciprocating Feed System Development Status

    NASA Technical Reports Server (NTRS)

    Trewek, Mary (Technical Monitor); Blackmon, James B.; Eddleman, David E.

    2005-01-01

    The reciprocating feed system (RFS) is an alternative means of providing high pressure propellant flow at low cost and system mass, with high fail-operational reliability. The RFS functions by storing the liquid propellants in large, low-pressure tanks and then expelling each propellant through two or three small, high-pressure tanks. Each RFS tank is sequentially filled, pressurized, expelled, vented, and refilled so as to provide a constant, or variable, mass flow rate to the engine. This type of system is much lighter than a conventional pressure fed system in part due to the greatly reduced amount of inert tank weight. The delivered payload for an RFS is superior to that of conventional pressure fed systems for conditions of high total impulse and it is competitive with turbopump systems, up to approximately 2000 psi. An advanced version of the RFS uses autogenous pressurization and thrust augmentation to achieve higher performance. In this version, the pressurization gases are combusted in a small engine, thus making the pressurization system, in effect, part of the propulsion system. The RFS appears to be much less expensive than a turbopump system, due to reduced research and development cost and hardware cost, since it is basically composed of small high- pressure tanks, a pressurization system, and control valves. A major benefit is the high reliability fail-operational mode; in the event of a failure in one of the three tank-systems, it can operate on the two remaining tanks. Other benefits include variable pressure and flow rates, ease of engine restart in micro-gravity, and enhanced propellant acquisition and control under adverse acceleration conditions. We present a system mass analysis tool that accepts user inputs for various design and mission parameters and calculates such output values payload and vehicle weights for the conventional pressure fed system, the RFS, the Autogenous Pressurization Thrust Augmentation (APTA) RFS, and turbopump systems

  19. Evolution of cooperation by generalized reciprocity

    PubMed Central

    Pfeiffer, Thomas; Rutte, Claudia; Killingback, Timothy; Taborsky, Michael; Bonhoeffer, Sebastian

    2005-01-01

    The evolution of cooperation by direct reciprocity requires that individuals recognize their present partner and remember the outcome of their last encounter with that specific partner. Direct reciprocity thus requires advanced cognitive abilities. Here, we demonstrate that if individuals repeatedly interact within small groups with different partners in a two person Prisoner's Dilemma, cooperation can emerge and also be maintained in the absence of such cognitive capabilities. It is sufficient for an individual to base their decision of whether or not to cooperate on the outcome of their last encounter—even if it was with a different partner. PMID:16024372

  20. Feasibility analysis of reciprocating magnetic heat pumps

    NASA Technical Reports Server (NTRS)

    Larson, A. V.; Hartley, J. G.; Shelton, Sam V.; Smith, M. M.

    1989-01-01

    A reciprocating gadolinium core in a regeneration fluid column in the warm bore of a superconducting solenoidal magnet is considered for magnetic refrigeration in 3.517 MW (1000 ton) applications. A procedure is presented to minimize the amount of superconducting cable needed in the magnet design. Estimated system capital costs for an ideal magnetic refrigerator of this type become comparable to conventional chillers as the frequency of reciprocation approaches 10 Hertz. A 1-D finite difference analysis of a regenerator cycling at 0.027 Hertz is presented which exhibits some of the features seen in the experiments of G. V. Brown.

  1. Analysis of reciprocating compressor piston rod failures

    SciTech Connect

    Tripp, H.A.; Drosjack, M.J.

    1984-02-01

    This report presents the analysis of five piston rod failures which occurred on reciprocating compressors. Calculations are shown for rod stress which includes nominal rod loading sources as well as additional loads due to unusual pressure losses in the compressor valves, flexure of the rods due to misalignment, and manufacturing errors. The additional loads were incorporated on the basis of field measurements. The stress values are used with Baquin's equation to produce fatigue life curves for the rods. Based on the calculations, recommendations for modified rods were made. The calculation procedures are described in a manner which will permit their application to other reciprocating compressors.

  2. From Born Reciprocity to Reciprocal Relativity: A Paradigm for Space-Time Physics

    NASA Astrophysics Data System (ADS)

    Jarvis, Peter

    Born's principle of reciprocity -- the exchangeability of relativistic energy-momentum and time-position -- can be seen as a discrete element of a continuous group of symmetry transformations which transcend relativity. Invariance under the semi-direct product of the Weyl-Heisenberg group H(4) of canonical commutation relations with the non-compact unitary group U(3, 1) -- the so-called quaplectic group U(3, 1) ⋉ H(4) -- has been considered by Low as an extension of Born reciprocity to a fundamental symmetry principle of `reciprocal relativity' for the physics of non-inertial frames and high energy processes...

  3. Radio detection of cosmic ray induced air showers at the Pierre Auger Observatory

    NASA Astrophysics Data System (ADS)

    Fliescher, Stefan; Pierre Auger Collaboration

    2012-01-01

    AERA—the Auger Engineering Radio Array—is currently being set up at the southern site of the Pierre Auger Observatory. AERA will explore the potential of the radio-detection technique to cosmic ray induced air showers with respect to the next generation of large-scale surface detectors. As AERA is co-located with the low-energy enhancements of the Pierre Auger Observatory, the observation of air showers in coincidence with the Auger surface and fluorescence detector will allow to study the radio emission processes in detail and to calibrate the radio signal. Finally, the combined reconstruction of shower parameters with three independent techniques promises new insights into the nature of cosmic rays in the transition region from 1017 to 1019 eV.Besides the detection of coherent radiation in the MHz frequency range, the setups AMBER—Air-shower Microwave Bremsstrahlung Experimental Radiometer—and MIDAS—MIcrowave Detection of Air Showers—prepare to check the possibility to detect air showers due the emission of molecular bremsstrahlung in the GHz range at the Auger site.This article presents the status of the radio-detection setups and discusses their physics potential as well as experimental challenges. Special focus is laid on the first stage of AERA which is the startup to the construction of a 20 km2 radio array.

  4. The role of metal ions in X-ray-induced photochemistry.

    PubMed

    Stumpf, V; Gokhberg, K; Cederbaum, L S

    2016-03-01

    Metal centres in biomolecules are recognized as being particularly sensitive to radiation damage by X-ray photons. This results in such molecules being both susceptible to an effective X-ray-induced loss of function and problematic to study using X-ray diffraction methods, with reliable structures of the metal centres difficult to obtain. Despite the abundance of experimental evidence, the mechanistic details of radiation damage at metal centres are unclear. Here, using ab initio calculations, we show that the absorption of X-rays by microsolvated Mg(2+) results in a complicated chain of ultrafast electronic relaxation steps that comprise both intra- and intermolecular processes and last for a few hundred femtoseconds. At the end of this cascade the metal reverts to its original charge state, the immediate environment becomes multiply ionized and large concentrations of radicals and slow electrons build up in the metal's vicinity. We conclude that such cascades involving metal ions are essential to our understanding of radiation chemistry and radiation damage in biological environments.

  5. Study of single and combined mass-sensitive observables of cosmic ray induced extensive air showers

    NASA Astrophysics Data System (ADS)

    Rastegarzadeh, G.; Nemati, M.

    2016-03-01

    In this study, combinations of the global arrival time, (Δτ_{global}), pseudorapidity, and lateral density distribution (ρ_{μ}) of muons, which are three mass-sensitive observables of cosmic ray induced extensive air showers, have been used as new parameters to study the primary mass discrimination around the knee energies (100 TeV-10 PeV). This is a simulation-based study and the simulations have been performed for the KASCADE array at Karlsruhe and the Alborz-I array at Tehran to study the effect of the altitude on the quality of the primary mass discrimination. The merit factors of the single and combined three mass-sensitive observables have been calculated to compare the discrimination power of combined and single observables. We have used the CORSIKA 7.4 code to simulate the extensive air showers (EASs) sample sets. Considering all aspects of our study, it is found that the ratio of the global time to the lateral density distribution of the muons gives better results than other ratios; also in the case of single observables, the muon density gives better results compared with the other observables. Also it is shown that below 1 PeV primary energies, the ratio of the muon global time to the muon density (Δτ_{global}/ρ_{μ}) results in a better mass discrimination relative to the muon density only.

  6. Protective effect of ethanol on X-ray-induced mitotic recombination in drosophilia melanogaster

    SciTech Connect

    Palermo, A.M.; Rey, M.; Munoz, E.R.

    1994-12-31

    The effect of ethanol treatment on X-ray-induced mitotic recombination in D. melanogaster females was investigated by means of the white/white{sup +} w/w{sup +} spot test. White females inseminated by yellow males were allowed to oviposit for 8 hr on medium containing 5%, 7.5% and 10% (v/v) ethanol and submitted to 10 Gy of X-rays 52 hr after the beginning of the egg laying period (chronic treatments). For acute treatments 56 {+-}4-hr-old larvae grown in regular medium were held in petri dishes containing filter paper soaked with 50% (v/v) ethanol for 30 min before being irradiated with 10 Gy. The emerging heterozygous w/w{sup +} females were inspected for the presence of white spots (LS) in their eyes. Acute ethanol pretreatments lead to a significant reduction in the frequency of LS. This is suggested to be due to the scavenging by ethanol of free radicals originating during irradiation. If so, the contribution of the indirect action of radiation to mitotic recombination induced by X-rays must be significant. Chronic ethanol pretreatments also resulted in a decrease of LS, though impairment of larval development by ethanol may have partly contributed to the effect observed. At the concentrations tested, ethanol by itself did not modify the frequency of LS observed in the control. 29 refs., 4 tabs.

  7. Robustness of SuperJunction structures against cosmic ray induced breakdown

    NASA Astrophysics Data System (ADS)

    Antoniou, Marina; Udrea, Florin; Bauer, Friedhelm

    2010-04-01

    In this paper we present a new design approach which dramatically improves the robustness of power semiconductor device against cosmic rays induced breakdown. This failure mode occurs during continuous operation at a DC rail voltage, which in practice is well below the breakdown rating (typically half of the breakdown). This failure is more prominent for higher breakdown rated devices (above 2 kV) and represents one of the main causes of concern, especially if the power systems are operated at higher altitude. Using a mathematical model for the calculation of the cosmic ray breakdown failure rate proposed by Zeller [1], we show that by employing a SuperJunction structure in the drift region of a high voltage diode we can achieve a great improvement in the robustness of the device against cosmic ray radiation. Since the cosmic ray failure rate is strongly dependent on the electric field distribution, the two-dimensional nature of the SuperJunction electric field with lower peaks and more even distribution offers a huge advantage over the use of standard PiN devices. Finally, a physical two-dimensional electric field model for the SuperJunction structures is developed which is then imported into Zeller's model to compute the cosmic ray failure rate for different DC voltage rails.

  8. 47 CFR 51.703 - Reciprocal compensation obligation of LECs.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 47 Telecommunication 3 2010-10-01 2010-10-01 false Reciprocal compensation obligation of LECs. 51.703 Section 51.703 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) COMMON CARRIER SERVICES (CONTINUED) INTERCONNECTION Reciprocal Compensation for Transport and Termination...

  9. Development of Trust and Reciprocity in Adolescence

    ERIC Educational Resources Information Center

    van den Bos, Wouter; Westenberg, Michiel; van Dijk, Eric; Crone, Eveline A.

    2010-01-01

    We investigate the development of two types of prosocial behavior, trust and reciprocity, as defined using a game-theoretical task that allows investigation of real-time social interaction, among 4 age groups from 9 to 25 years. By manipulating the possible outcome alternatives, we could distinguish among important determinants of trust and…

  10. Cooperation under indirect reciprocity and imitative trust.

    PubMed

    Saavedra, Serguei; Smith, David; Reed-Tsochas, Felix

    2010-10-27

    Indirect reciprocity, a key concept in behavioral experiments and evolutionary game theory, provides a mechanism that allows reciprocal altruism to emerge in a population of self-regarding individuals even when repeated interactions between pairs of actors are unlikely. Recent empirical evidence show that humans typically follow complex assessment strategies involving both reciprocity and social imitation when making cooperative decisions. However, currently, we have no systematic understanding of how imitation, a mechanism that may also generate negative effects via a process of cumulative advantage, affects cooperation when repeated interactions are unlikely or information about a recipient's reputation is unavailable. Here we extend existing evolutionary models, which use an image score for reputation to track how individuals cooperate by contributing resources, by introducing a new imitative-trust score, which tracks whether actors have been the recipients of cooperation in the past. We show that imitative trust can co-exist with indirect reciprocity mechanisms up to a threshold and then cooperation reverses -revealing the elusive nature of cooperation. Moreover, we find that when information about a recipient's reputation is limited, trusting the action of third parties towards her (i.e. imitating) does favor a higher collective cooperation compared to random-trusting and share-alike mechanisms. We believe these results shed new light on the factors favoring social imitation as an adaptive mechanism in populations of cooperating social actors.

  11. Upstream reciprocity and the evolution of gratitude.

    PubMed

    Nowak, Martin A; Roch, Sébastien

    2007-03-01

    If someone is nice to you, you feel good and may be inclined to be nice to somebody else. This every day experience is borne out by experimental games: the recipients of an act of kindness are more likely to help in turn, even if the person who benefits from their generosity is somebody else. This behaviour, which has been called 'upstream reciprocity', appears to be a misdirected act of gratitude: you help somebody because somebody else has helped you. Does this make any sense from an evolutionary or a game theoretic perspective? In this paper, we show that upstream reciprocity alone does not lead to the evolution of cooperation, but it can evolve and increase the level of cooperation if it is linked to either direct or spatial reciprocity. We calculate the random walks of altruistic acts that are induced by upstream reciprocity. Our analysis shows that gratitude and other positive emotions, which increase the willingness to help others, can evolve in the competitive world of natural selection.

  12. Weak reciprocity alone cannot explain peer punishment.

    PubMed

    Casari, Marco

    2012-02-01

    The claims about (1) the lack of empirical support for a model of strong reciprocation and (2) the irrelevant empirical role of costly punishment to support cooperation in the field need qualifications. The interpretation of field evidence is not straightforward, and other-regarding preferences are also likely to play a role in the field.

  13. The Effects of Feedback as Interpersonal Reciprocities

    ERIC Educational Resources Information Center

    Levenstein, Joseph; And Others

    1977-01-01

    Tests the hypothesis that a response to a given feedback statement will be its reciprocal. In Phase 1, a pool of feedback statements was written and scaled along dimensions of power (dominance-submission) and affect (affection-hostility). In Phase 2, these statements were used as the basis for giving feedback and replying to it. (Author)

  14. 36 CFR 251.63 - Reciprocity.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 251.63 Parks, Forests, and Public Property FOREST SERVICE, DEPARTMENT OF AGRICULTURE LAND USES Special Uses § 251.63 Reciprocity. If it is determined that a right-of-way shall be needed by the United States... across Federal lands, the authorized officer may condition a special use authorization to require...

  15. 36 CFR 251.63 - Reciprocity.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 251.63 Parks, Forests, and Public Property FOREST SERVICE, DEPARTMENT OF AGRICULTURE LAND USES Special Uses § 251.63 Reciprocity. If it is determined that a right-of-way shall be needed by the United States... across Federal lands, the authorized officer may condition a special use authorization to require...

  16. 36 CFR 251.63 - Reciprocity.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 251.63 Parks, Forests, and Public Property FOREST SERVICE, DEPARTMENT OF AGRICULTURE LAND USES Special Uses § 251.63 Reciprocity. If it is determined that a right-of-way shall be needed by the United States... across Federal lands, the authorized officer may condition a special use authorization to require...

  17. 36 CFR 251.63 - Reciprocity.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 251.63 Parks, Forests, and Public Property FOREST SERVICE, DEPARTMENT OF AGRICULTURE LAND USES Special Uses § 251.63 Reciprocity. If it is determined that a right-of-way shall be needed by the United States... across Federal lands, the authorized officer may condition a special use authorization to require...

  18. 36 CFR 251.63 - Reciprocity.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 251.63 Parks, Forests, and Public Property FOREST SERVICE, DEPARTMENT OF AGRICULTURE LAND USES Special Uses § 251.63 Reciprocity. If it is determined that a right-of-way shall be needed by the United States... across Federal lands, the authorized officer may condition a special use authorization to require...

  19. 46 CFR 8.120 - Reciprocity.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... § 8.120 Reciprocity. (a) The Commandant may delegate authority to a classification society that has... in paragraph (a) of this section are satisfied, a classification society must provide to the Coast Guard an affidavit, from the government of the country that the classification society is...

  20. 46 CFR 8.120 - Reciprocity.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... § 8.120 Reciprocity. (a) The Commandant may delegate authority to a classification society that has... in paragraph (a) of this section are satisfied, a classification society must provide to the Coast Guard an affidavit, from the government of the country that the classification society is...

  1. Reciprocity in Preschool Peers' Social Interaction.

    ERIC Educational Resources Information Center

    Chiu, Jih-Perng Peter

    This study sought to describe the norms of reciprocity in social interaction from the viewpoint of immediate behavioral exchanges by examining the social interaction of preschool peers in a free-play situation. Seventeen 4-year-old children, eight girls and nine boys, were observed during free play activity periods after a picture sociometric test…

  2. 37 CFR 11.24 - Reciprocal discipline.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... case by clear and convincing evidence that the practitioner violated 37 CFR 10.23, as further identified under 37 CFR 10.23(c)(5), (or any successor regulation identifying such public censure, public... 37 Patents, Trademarks, and Copyrights 1 2010-07-01 2010-07-01 false Reciprocal discipline....

  3. 37 CFR 11.24 - Reciprocal discipline.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... case by clear and convincing evidence that the practitioner violated 37 CFR 10.23, as further identified under 37 CFR 10.23(c)(5), (or any successor regulation identifying such public censure, public... 37 Patents, Trademarks, and Copyrights 1 2012-07-01 2012-07-01 false Reciprocal discipline....

  4. 37 CFR 11.24 - Reciprocal discipline.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 37 Patents, Trademarks, and Copyrights 1 2014-07-01 2014-07-01 false Reciprocal discipline. 11.24... discipline. (a) Notification of OED Director. Within thirty days of being publicly censured, publicly... USPTO Director. The OED Director shall, in addition, without Committee on Discipline authorization,...

  5. 37 CFR 11.24 - Reciprocal discipline.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... case by clear and convincing evidence that the practitioner violated 37 CFR 10.23, as further identified under 37 CFR 10.23(c)(5), (or any successor regulation identifying such public censure, public... 37 Patents, Trademarks, and Copyrights 1 2011-07-01 2011-07-01 false Reciprocal discipline....

  6. 37 CFR 11.24 - Reciprocal discipline.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 37 Patents, Trademarks, and Copyrights 1 2013-07-01 2013-07-01 false Reciprocal discipline. 11.24... discipline. (a) Notification of OED Director. Within thirty days of being publicly censured, publicly... USPTO Director. The OED Director shall, in addition, without Committee on Discipline authorization,...

  7. Tuition Reciprocity in the United States

    ERIC Educational Resources Information Center

    Stewart, Gregory; Wright, Dianne Brown; Kennedy, Angelica

    2008-01-01

    Reciprocity agreements are contracts between two or more parties whereby students pay reduced tuition rates. The rate of reduction is determined by the parameters set forth in each individual state's agreement but may range from a modest reduction in fees to a waiver of full non-resident tuition. In addition to providing tuition relief,…

  8. Reciprocal Relationships between Attitude toward Mathematics and Achievement in Mathematics.

    ERIC Educational Resources Information Center

    Ma, Xin

    1997-01-01

    This study examined reciprocal relationships between attitude toward mathematics and mathematics achievement. High school seniors from the Dominican Republic completed mathematics achievement tests and a questionnaire on mathematics attitudes. Results indicated that reciprocal relationships existed, suggesting that the reciprocal nature between…

  9. 30 CFR 56.13010 - Reciprocating-type air compressors.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Reciprocating-type air compressors. 56.13010... NONMETAL MINE SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-SURFACE METAL AND NONMETAL MINES Compressed Air and Boilers § 56.13010 Reciprocating-type air compressors. (a) Reciprocating-type air...

  10. 30 CFR 56.13010 - Reciprocating-type air compressors.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Reciprocating-type air compressors. 56.13010... NONMETAL MINE SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-SURFACE METAL AND NONMETAL MINES Compressed Air and Boilers § 56.13010 Reciprocating-type air compressors. (a) Reciprocating-type air...

  11. 30 CFR 56.13010 - Reciprocating-type air compressors.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Reciprocating-type air compressors. 56.13010... NONMETAL MINE SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-SURFACE METAL AND NONMETAL MINES Compressed Air and Boilers § 56.13010 Reciprocating-type air compressors. (a) Reciprocating-type air...

  12. Familial Reciprocity and Subjective Well-Being in Ghana

    ERIC Educational Resources Information Center

    Tsai, Ming-Chang; Dzorgbo, Dan-Bright S.

    2012-01-01

    The authors investigated variations in reciprocity and the impact of reciprocity on well-being in a West African society. They hypothesized that household size and income diversity encourage reciprocity, which in turn enhances subjective well-being. In empirical testing of these hypotheses the authors used the data of the Core Welfare Indicators…

  13. 47 CFR 51.711 - Symmetrical reciprocal compensation.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 47 Telecommunication 3 2010-10-01 2010-10-01 false Symmetrical reciprocal compensation. 51.711... (CONTINUED) INTERCONNECTION Reciprocal Compensation for Transport and Termination of Telecommunications Traffic § 51.711 Symmetrical reciprocal compensation. (a) Rates for transport and termination...

  14. Short-Term Reciprocity in Late Parent-Child Relationships

    ERIC Educational Resources Information Center

    Leopold, Thomas; Raab, Marcel

    2011-01-01

    Long-term concepts of parent-child reciprocity assume that the amount of support given and received is only balanced in a generalized fashion over the life course. We argue that reciprocity in parent-child relationships also operates in the short term. Our analysis of short-term reciprocity focuses on concurrent exchange in its main upward and…

  15. Role of x-ray-induced transcripts in adaptive responses following x-rays

    SciTech Connect

    Boothman, D.A.

    1992-01-01

    Potentially lethal damage repair (PLDR) and sublethal damage repair, may be the same manifestations of a series of common enzymatic steps. PLDR, has two distinct phases based upon DNA lesion repair and survival recovery studies. The first phase of PLDR occurs very quickly (t{sub {1/2}}:2--20 mins) to increase the survival of X-irradiated cells by mending the vast array of DNA lesions created by ionizing radiation. The second slower phase of PLDR proceeds much later (i.e., >1--2 hrs) following X-irradiation, during which the remaining double-stranded DNA breaks are completely repaired. This second phase of repair closely corresponds to the restructuring of gross chromosomal damage, and can be partially blocked in some human cells by inhibiting protein synthesis. This slower phase of PLDR correlated with a rapid decline in X-ray-induced transformation of normal cells. The fast component of PLDR may be due to constitutively synthesized DNA ligases, topoisomerases, or polymerases, which act immediately to repair damaged, DNA. In contrast, the slow phase of PLDR in human cells may require the induction of specific genes and gene product's involved in the repair of potentially lethal or carcinogenic DNA lesions. Induced gene products (i.e., proteins) specifically synthesized in response to physiological doses of ionizing radiation in radioresistant human melanoma (U1-Mel) cells, and in a variety of other human normal and cancer-prone cells, were identified using two-dimensional gel electrophoresis. We identified and partially characterized ten proteins synthesized by U1-Mel cells. The synthesis of eight of these proteins were specifically induced by ionizing radiation and two proteins were repressed Neither heat shock, UV-irradiation, nor bifunctional alkylating agent treatments resulted in the induction of these proteins. The expression of one protein, XIP269, correlated very well with PLDR capacity.

  16. Genetics of x-ray induced double strand break repair in saccharomyces cerevisiae

    SciTech Connect

    Budd, M.E.

    1982-07-01

    The possible fates of x-ray-induced double-strand breaks in Saccharomyces cerevisiae were examined. One possible pathway which breaks can follow, the repair pathway, was studied by assaying strains with mutations in the RAD51, RAD54, and RAD57 loci for double-strand break repair. In order of increasing radiation sensitivity one finds: rad57-1(23/sup 0/)> rad51-1(30/sup 0/)> rad54-3(36/sup 0/). At 36/sup 0/, rad54-3 cells cannot repair double-strand breaks, while 23/sup 0/, they can. Strains with the rad57-1 mutation can rejoin broken chromosomes at both temperatures. However, the low survival at 36/sup 0/ shows that the assay is not distinguishing large DNA fragments which allow cell survival from those which cause cell death. A rad51-1 strain could also rejoin broken chromosomes, and was thus capable of incomplete repair. The data can be explained with the hypothesis that rad54-3 cells are blocked in an early step of repair, while rad51-1 and rad57-1 strains are blocked in a later step of repair. The fate of double-strand breaks when they are left unrepaired was investigated with the rad54-3 mutation. If breaks are prevented from entering the RAD54 repair pathway they become uncommitted lesions. These lesions are repaired slower than the original breaks. One possible fate for an uncommitted lesion is conversion into a fixed lesion, which is likely to be an unrepairable or misrepaired double-strand break. The presence of protein synthesis after irradiation increases the probability that a break will enter the repair pathway. Evidence shows that increased probability of repair results from enhanced synthesis of repair proteins shortly after radiation. (ERB)

  17. Proton and γ-ray Induced Radiation Effects on 1 Gbit LPDDR SDRAM Fabricated on Epitaxial Wafer for Space Applications

    NASA Astrophysics Data System (ADS)

    Park, Mi Young; Chae, Jang-Soo; Lee, Chol; Lee, Jungsu; Shin, Im Hyu; Kim, Ji Eun

    2016-09-01

    We present proton-induced single event effects (SEEs) and γ-ray-induced total ionizing dose (TID) data for 1 Gbit lowpower double data rate synchronous dynamic random access memory (LPDDR SDRAM) fabricated on a 5 μm epitaxial layer (54 nm complementary metal-oxide-semiconductor (CMOS) technology). We compare our radiation tolerance data for LPDDR SDRAM with those of general DDR SDRAM. The data confirms that our devices under test (DUTs) are potential candidates for space flight applications.

  18. X-ray induced dimerization of cinnamic acid: Time-resolved inelastic X-ray scattering study

    PubMed Central

    Inkinen, Juho; Niskanen, Johannes; Talka, Tuomas; Sahle, Christoph J.; Müller, Harald; Khriachtchev, Leonid; Hashemi, Javad; Akbari, Ali; Hakala, Mikko; Huotari, Simo

    2015-01-01

    A classic example of solid-state topochemical reactions is the ultraviolet-light induced photodimerization of α-trans-cinnamic acid (CA). Here, we report the first observation of an X-ray-induced dimerization of CA and monitor it in situ using nonresonant inelastic X-ray scattering spectroscopy (NRIXS). The time-evolution of the carbon core-electron excitation spectra shows the effects of two X-ray induced reactions: dimerization on a short time-scale and disintegration on a long time-scale. We used spectrum simulations of CA and its dimerization product, α-truxillic acid (TA), to gain insight into the dimerization effects. From the time-resolved spectra, we extracted component spectra and time-dependent weights corresponding to CA and TA. The results suggest that the X-ray induced dimerization proceeds homogeneously in contrast to the dimerization induced by ultraviolet light. We also utilized the ability of NRIXS for direct tomography with chemical-bond contrast to image the spatial progress of the reactions in the sample crystal. Our work paves the way for other time-resolved studies on chemical reactions using inelastic X-ray scattering. PMID:26568420

  19. X-ray induced dimerization of cinnamic acid: Time-resolved inelastic X-ray scattering study

    NASA Astrophysics Data System (ADS)

    Inkinen, Juho; Niskanen, Johannes; Talka, Tuomas; Sahle, Christoph J.; Müller, Harald; Khriachtchev, Leonid; Hashemi, Javad; Akbari, Ali; Hakala, Mikko; Huotari, Simo

    2015-11-01

    A classic example of solid-state topochemical reactions is the ultraviolet-light induced photodimerization of α-trans-cinnamic acid (CA). Here, we report the first observation of an X-ray-induced dimerization of CA and monitor it in situ using nonresonant inelastic X-ray scattering spectroscopy (NRIXS). The time-evolution of the carbon core-electron excitation spectra shows the effects of two X-ray induced reactions: dimerization on a short time-scale and disintegration on a long time-scale. We used spectrum simulations of CA and its dimerization product, α-truxillic acid (TA), to gain insight into the dimerization effects. From the time-resolved spectra, we extracted component spectra and time-dependent weights corresponding to CA and TA. The results suggest that the X-ray induced dimerization proceeds homogeneously in contrast to the dimerization induced by ultraviolet light. We also utilized the ability of NRIXS for direct tomography with chemical-bond contrast to image the spatial progress of the reactions in the sample crystal. Our work paves the way for other time-resolved studies on chemical reactions using inelastic X-ray scattering.

  20. Experimental realization of optomechanically induced non-reciprocity

    NASA Astrophysics Data System (ADS)

    Shen, Zhen; Zhang, Yan-Lei; Chen, Yuan; Zou, Chang-Ling; Xiao, Yun-Feng; Zou, Xu-Bo; Sun, Fang-Wen; Guo, Guang-Can; Dong, Chun-Hua

    2016-10-01

    Non-reciprocal devices, such as circulators and isolators, are indispensable components in classical and quantum information processing in integrated photonic circuits. Aside from these applications, the non-reciprocal phase shift is of fundamental interest for exploring exotic topological photonics, such as the realization of chiral edge states and topological protection. However, incorporating low-optical-loss magnetic materials into a photonic chip is technically challenging. In this study we experimentally demonstrate non-magnetic non-reciprocity using optomechanical interactions in a whispering gallery microresonator, as proposed in a previous work. Optomechanically induced non-reciprocal transparency and amplification are observed and a non-reciprocal phase shift of up to 40° is also demonstrated. The underlying mechanism of optomechanically induced non-reciprocity has great potential for all-optical controllable isolators and circulators, as well as non-reciprocal phase shifters in integrated photonic chips.

  1. Condition monitoring of reciprocating seal based on FBG sensors

    NASA Astrophysics Data System (ADS)

    Zhao, Xiuxu; Zhang, Shuanshuan; Wen, Pengfei; Zhen, Wenhan; Ke, Wei

    2016-07-01

    The failure of hydraulic reciprocating seals will seriously affect the normal operation of hydraulic reciprocating machinery, so the potential fault condition monitoring of reciprocating seals is very important. However, it is extremely difficult because of the limitation of reciprocating motion and the structure constraints of seal groove. In this study, an approach using fiber Bragg grating (FBG) sensors is presented. Experimental results show that the contact strain changes of a reciprocating seal can be detected by FBG sensors in the operation process of the hydraulic cylinders. The failure condition of the reciprocating seal can be identified by wavelet packet energy entropy, and the center frequency of power spectrum analysis. It can provide an effective solution for the fault prevention and health management of reciprocating hydraulic rod seals.

  2. Microelectromechanical reciprocating-tooth indexing apparatus

    SciTech Connect

    Allen, James J.

    1999-01-01

    An indexing apparatus is disclosed that can be used to rotate a gear or move a rack in a precise, controllable manner. The indexing apparatus, based on a reciprocating shuttle driven by one or more actuators, can be formed either as a micromachine, or as a millimachine. The reciprocating shuttle of the indexing apparatus can be driven by a thermal, electrostatic or electromagnetic actuator, with one or more wedge-shaped drive teeth of the shuttle being moveable to engage and slide against indexing teeth on the gear or rack, thereby moving the gear or rack. The indexing apparatus can be formed by either surface micromachining processes or LIGA processes, depending on the size of the apparatus that is to be formed.

  3. Reciprocity in Adolescent and Caregiver Violence

    PubMed Central

    Bartle-Haring, Suzanne; Slesnick, Natasha; Carmona, Jasmin

    2014-01-01

    Over a 2-year period, with assessments every six months, the reciprocity in violent behaviors (verbal and physical) was investigated in a sample of 161 adolescents, who met the criteria for substance or alcohol abuse or dependence, and their caregivers, who participated in a clinical trial for family treatment for adolescent substance abuse. Using observed variables in a structural equation model with panel data, there was very little stability in violent behaviors across time from the perspectives of both the adolescents and caregivers. Evidence for violence reciprocity between adolescent and caregiver was demonstrated toward the end of the study period. The results are discussed in the context of previous literature about adolescent-to-parent violence. PMID:25684856

  4. Reciprocal allopreening in the Brownheaded Nuthatch

    USGS Publications Warehouse

    Barbour, D.B.; DeGange, A.R.

    1982-01-01

    In his extensive reviews of allopreening, Harrison (1965, 1969) did not record this behavior for the Sittidae, nor did Kilham (1968, 1972, 1973) mention observing this behavior in either White-breasted (Sitta carolinensis) or Red-breasted (S. canadensis) nuthatches. Norris (1958: 187), however, mentioned the occurrence of allopreening in Brown-headed Nuthatches (S. pusilia), in passing. Here we relate our observations of reciprocal allopreening between two Brown-headed Nuthatches.

  5. Feasibility analysis of reciprocating magnetic heat pumps

    NASA Technical Reports Server (NTRS)

    Larson, A. V.; Hartley, J. G.; Shelton, S. V.; Smith, M. M.

    1986-01-01

    The conceptual design selected for detailed system analysis and optimization is the reciprocating gadolinium core in a regenerative fluid column within the bore of a superconducting magnet. The thermodynamic properties of gadolinium are given. A computerized literature search for relevant papers was conducted and is being analyzed. Contact was made with suppliers of superconducting magnets and accessories, magnetic materials, and various types of hardware. A description of the model for the thermal analysis of the core and regenerator fluids is included.

  6. Variable-Aperture Reciprocating Reed Valve

    NASA Technical Reports Server (NTRS)

    Lindner, Jeffrey L. (Inventor); Myers, W. Neill (Inventor); Kelley, Anthony R. (Inventor); Yang, Hong Q. (Inventor)

    2015-01-01

    A variable-aperture reciprocating reed valve includes a valve body defining a through hole region having a contoured-profile portion. A semi-rigid plate is affixed on one side thereof to the valve body to define a cantilever extending across the through hole region. At least one free edge of the cantilever opposes the contoured-profile portion of the through hole region in a non-contact relationship.

  7. Upstream reciprocity and the evolution of gratitude

    PubMed Central

    Nowak, Martin A; Roch, Sébastien

    2006-01-01

    If someone is nice to you, you feel good and may be inclined to be nice to somebody else. This every day experience is borne out by experimental games: the recipients of an act of kindness are more likely to help in turn, even if the person who benefits from their generosity is somebody else. This behaviour, which has been called ‘upstream reciprocity’, appears to be a misdirected act of gratitude: you help somebody because somebody else has helped you. Does this make any sense from an evolutionary or a game theoretic perspective? In this paper, we show that upstream reciprocity alone does not lead to the evolution of cooperation, but it can evolve and increase the level of cooperation if it is linked to either direct or spatial reciprocity. We calculate the random walks of altruistic acts that are induced by upstream reciprocity. Our analysis shows that gratitude and other positive emotions, which increase the willingness to help others, can evolve in the competitive world of natural selection. PMID:17254983

  8. Nutating spider crank reciprocating piston machine

    SciTech Connect

    Shaffer, J.E.

    1991-07-02

    This patent describes reciprocating piston apparatus. It comprises a housing; a shaft journalled on the housing for rotation about a shaft axis; a plurality of cylinders each having a central longitudinal axis and disposed parallel to the shaft axis and located on the housing at positions angularly-spaced circumferentially about the shaft; a plurality of double-acting pistons having piston axes and centers, each the piston having a transverse bore therein and being respectively mounted for reciprocation within corresponding ones of the cylinders, each the bore having a longitudinal central axis normal to the respective cylinder axis; a mutating spider having a central hub portion mounted on the shaft obliquely of the shaft axis, and having a plurality of branches extending radially outward from the hub portion and terminating at terminal ends; and means directly connecting the terminal ends centrally to corresponding ones of the bores for transferring motion between reciprocation of the pistons and rotation of the shaft, and for restraining the spider from rotating with the shaft.

  9. Grooming reciprocity in male Tibetan macaques.

    PubMed

    Xia, Dong-Po; Li, Jin-Hua; Garber, Paul A; Matheson, Megan D; Sun, Bing-Hua; Zhu, Yong

    2013-10-01

    In several primate species, adult males are reported to compete for access to reproductive partners as well as forming affiliative and cohesive social bonds based on the exchange of goods or services. We hypothesized that among a broad set of fitness-maximizing strategies, grooming can be used by individual adult males to enhance social relationships through reciprocity and/or through the interchange of grooming for a different but equivalent good or service. We used focal animal sampling and continuously recorded dyadic grooming and agonistic interactions to test a series of predictions regarding male social interactions in a free-ranging group of Tibetan macaques (Macaca thibetana) at Huangshan, China. During the non-mating season or between males of similar rank throughout the year, grooming effort given was matched by grooming effort received. However, lower ranking males groomed higher ranking males at a greater rate and/or for a longer duration during both the mating and non-mating periods. We found that higher ranking males directed less aggression towards males with whom they formed a frequent grooming partnership, indicating that grooming received was interchanged for increased social tolerance. These data suggest that individual male Tibetan macaques employ alternative social strategies associated with grooming reciprocity or interchange depending on dominance rank and rates of aggression, and highlight the importance of both biological markets and grooming reciprocity as behavioral mechanisms used by resident adult males to form and maintain affiliative social bonds.

  10. Compression ratio control in reciprocating piston engines

    SciTech Connect

    Doundoulakis, G.J.

    1989-08-29

    The patent describes compression ratio control for reciprocating piston engines. It comprises: a reciprocating engine crankcase; a plurality of compression/expansion cylinders rigidly attached to the crankcase; each of the cylinders including a curved surface and a cylinder head; a fuel mixture in-taken in the cylinders; a piston reciprocating along each cylinder's curved surface for providing compression/expansion to the fuel mixture; a crank mechanism including a crankshaft rotating about an axial line that is substantially equidistant from the heads, crankcheek lobes radially extending from the crankshaft, crankpins inside and in contact with crankpin bearings, axially extending between the crankcheek lobes, and crankshaft journal bearings for providing low frictional support to the crankshaft; a connecting rod for each of the cylinders connecting the piston with the crankpin; crankshaft positioning; a first transmission gear, a crankshaft gear for meshing with the transmission gear, and a slot cut on the crankcase; wherein the constraint in the displacement of the crankshaft in the horizontal sense is provided by the vertical edges of the slot, and wherein the vertical edges of the slot are preferably being curved with a radius of curvature substantially equal to the average pitch diameter of the crankshaft gear and thee first transmission gear for accurate meshing of the gears.

  11. Reciprocity theory of many-body interactions

    NASA Astrophysics Data System (ADS)

    Agbormbai, Adolf A.

    1990-01-01

    The reciprocity approach is applied to the problem of many body interactions in which an arbitrary number of molecules simultaneously collide with one another at the same impact point in physical space. First, the relevant features in the theory of binary collisions are reviewed, and then the problem of three bodies is considered. It is shown that this reduces to the motion of two particles in the center of mass frame, in contrast to the binary problem which reduces to the motion of a single particle in this frame of reference. It is shown how the three body analysis may be generalized to incorporate an arbitrary number of bodies. In particular, the N body problem is shown to reduce to the motion of N-1 bodies in the center of mass system each of which scatters in the manner described above as well as interchange energy with the others. For the inelastic encounters in which internal energy excitations occur, the problem is decomposed into an internal transational energy exchange superposed on the elastic scattering. The internal-external exchange is formulated statistically via the principle of reciprocity at equilibrium. Techniques are illustrated only for three body collisions, the aim being to formulate a reciprocity equation from which the statistical models of the exchange may be constructed.

  12. Recent gamma background measurements at high mountain altitude.

    PubMed

    Mishev, A L; Hristova, E

    2012-11-01

    Results from recent measurements of radiation gamma background at high mountain altitude, namely at Basic Environmental Observatory Moussala (42.11 N, 23.35 E, 2925 m a.s.l.) are reported. The measurements are fulfilled with several devices, namely IGS-421 gamma probe and MDU Liulin. A comparative analysis with previous measurements performed with SBN-90 SAPHYMO NaI(Tl) gamma probe is carried out. A temperature effect during winter period of SAPHYMO probe is observed. In addition the measurements are compared with CaSO(4):Dy TLD. The obtained results are widely discussed. A numerical model for galactic cosmic ray contribution to the dose rate in air is presented. The model is based on a full Monte Carlo simulation of cosmic ray induced cascade in the atmosphere. The simulation is carried out with CORSIKA 6.52 code using FLUKA 2006b and QGSJET II hadron interaction models. PMID:22659148

  13. Reciprocity or near-reciprocity of highly coupled enzymatic processes at the multidimensional inflection point.

    PubMed Central

    Caplan, S R

    1981-01-01

    It has recently been demonstrated that coupled enzymatic processes may possess, for a particular choice of the state variables, multidimensional inflection points in thermodynamic force-flow space. The conditions for reciprocity in the linear region near such a reference state, which may be far from equilibrium, are of considerable interest. It is shown by examining the associated Hill diagrams that all cycles in which a given pair of forces act contribute a corresponding pair of symmetrical terms to the Jacobian matrix characterizing perturbations about this stationary state. To the extent that these cycles dominate--i.e., to the extent that the system is highly coupled--reciprocity or near-reciprocity will be obeyed. This would be expected to be the case in most biological systems. PMID:6270670

  14. NADPH oxidase-mediated generation of reactive oxygen species: A new mechanism for X-ray-induced HeLa cell death

    SciTech Connect

    Liu Qing; He Xiaoqing; Liu Yongsheng; Du Bingbing; Wang Xiaoyan; Zhang Weisheng; Jia Pengfei; Dong Jingmei; Ma Jianxiu; Wang Xiaohu; Li Sha; Zhang Hong

    2008-12-19

    Oxidative damage is an important mechanism in X-ray-induced cell death. Radiolysis of water molecules is a source of reactive oxygen species (ROS) that contribute to X-ray-induced cell death. In this study, we showed by ROS detection and a cell survival assay that NADPH oxidase has a very important role in X-ray-induced cell death. Under X-ray irradiation, the upregulation of the expression of NADPH oxidase membrane subunit gp91{sup phox} was dose-dependent. Meanwhile, the cytoplasmic subunit p47{sup phox} was translocated to the cell membrane and localized with p22{sup phox} and gp91{sup phox} to form reactive NADPH oxidase. Our data suggest, for the first time, that NADPH oxidase-mediated generation of ROS is an important contributor to X-ray-induced cell death. This suggests a new target for combined gene transfer and radiotherapy.

  15. Reciprocity on the hardwood: passing patterns among professional basketball players.

    PubMed

    Willer, Robb; Sharkey, Amanda; Frey, Seth

    2012-01-01

    Past theory and research view reciprocal resource sharing as a fundamental building block of human societies. Most studies of reciprocity dynamics have focused on trading among individuals in laboratory settings. But if motivations to engage in these patterns of resource sharing are powerful, then we should observe forms of reciprocity even in highly structured group environments in which reciprocity does not clearly serve individual or group interests. To this end, we investigated whether patterns of reciprocity might emerge among teammates in professional basketball games. Using data from logs of National Basketball Association (NBA) games of the 2008-9 season, we estimated a series of conditional logistic regression models to test the impact of different factors on the probability that a given player would assist another player in scoring a basket. Our analysis found evidence for a direct reciprocity effect in which players who had "received" assists in the past tended to subsequently reciprocate their benefactors. Further, this tendency was time-dependent, with the probability of repayment highest soon after receiving an assist and declining as game time passed. We found no evidence for generalized reciprocity - a tendency to "pay forward" assists - and only very limited evidence for indirect reciprocity - a tendency to reward players who had sent others many assists. These findings highlight the power of reciprocity to shape human behavior, even in a setting characterized by extensive planning, division of labor, quick decision-making, and a focus on inter-group competition.

  16. Elemental mapping of planetary surfaces using gamma-ray spectroscopy

    SciTech Connect

    Reedy, R.C.

    1990-01-01

    The gamma rays escaping from a planet can be used to map the concentrations of various elements in its surface. In a planet, the high-energy particles in the galactic cosmic rays induce a cascade of particles that includes many neutrons. The {gamma} rays are made by the nuclear excitations induced by these cosmic-ray particles and their secondaries (especially capture or inelastic-scattering reactions induced by neutrons) and decay of the naturally-occurring radioelements. After a short history of planetary {gamma}-ray spectroscopy and its applications, the {gamma}-ray spectrometer planned for the Mars Observer mission is presented. The results of laboratory experiments that simulate the cosmic-ray bombardments of planetary surfaces or measure cross sections for the production of {gamma} rays and the status of the theoretical calculations for the processes that make and transport neutrons and {gamma} rays will be reviewed. The emphasis here is on studies of Mars and on new ideas, concepts, and problems that have arisen over the last decade, such as Doppler broadening and peaks from neutron scattering with germanium nuclei in a high-resolution {gamma}-ray spectrometer. 31 refs., 1 fig., 1 tab.

  17. Revisiting "The evolution of reciprocity in sizable groups": continuous reciprocity in the repeated n-person prisoner's dilemma.

    PubMed

    Takezawa, Masanori; Price, Michael E

    2010-05-21

    For many years in evolutionary science, the consensus view has been that while reciprocal altruism can evolve in dyadic interactions, it is unlikely to evolve in sizable groups. This view had been based on studies which have assumed cooperation to be discrete rather than continuous (i.e., individuals can either fully cooperate or else fully defect, but they cannot continuously vary their level of cooperation). In real world cooperation, however, cooperation is often continuous. In this paper, we re-examine the evolution of reciprocity in sizable groups by presenting a model of the n-person prisoner's dilemma that assumes continuous rather than discrete cooperation. This model shows that continuous reciprocity has a dramatically wider basin of attraction than discrete reciprocity, and that this basin's size increases with efficiency of cooperation (marginal per capita return). Further, we find that assortative interaction interacts synergistically with continuous reciprocity to a much greater extent than it does with discrete reciprocity. These results suggest that previous models may have underestimated reciprocity's adaptiveness in groups. However, we also find that the invasion of continuous reciprocators into a population of unconditional defectors becomes realistic only within a narrow parameter space in which the efficiency of cooperation is close to its maximum bound. Therefore our model suggests that continuous reciprocity can evolve in large groups more easily than discrete reciprocity only under unusual circumstances.

  18. Reputation for reciprocity engages the brain reward center

    PubMed Central

    Phan, K. Luan; Sripada, Chandra Sekhar; Angstadt, Mike; McCabe, Kevin

    2010-01-01

    Brain reward circuitry, including ventral striatum and orbitofrontal cortex, has been independently implicated in preferences for fair and cooperative outcomes as well as learning of reputations. Using functional MRI (fMRI) and a “trust game” task involving iterative exchanges with fictive partners who acquire different reputations for reciprocity, we measured brain responses in 36 healthy adults when positive actions (entrust investment to partners) yield positive returns (reciprocity) and how these brain responses are modulated by partner reputation for repayment. Here we show that positive reciprocity robustly engages the ventral striatum and orbitofrontal cortex. Moreover, this signal of reciprocity in the ventral striatum appears selectively in response to partners who have consistently returned the investment (e.g., a reputation for reciprocity) and is absent for partners who lack a reputation for reciprocity. These findings elucidate a fundamental brain mechanism, via reward-related neural substrates, by which human cooperative relationships are initiated and sustained. PMID:20615982

  19. Mortality salience increases personal relevance of the norm of reciprocity.

    PubMed

    Schindler, Simon; Reinhard, Marc-André; Stahlberg, Dagmar

    2012-10-01

    Research on terror management theory found evidence that people under mortality salience strive to live up to salient cultural norms and values, like egalitarianism, pacifism, or helpfulness. A basic, strongly internalized norm in most human societies is the norm of reciprocity: people should support those who supported them (i.e., positive reciprocity), and people should injure those who injured them (i.e., negative reciprocity), respectively. In an experiment (N = 98; 47 women, 51 men), mortality salience overall significantly increased personal relevance of the norm of reciprocity (M = 4.45, SD = 0.65) compared to a control condition (M = 4.19, SD = 0.59). Specifically, under mortality salience there was higher motivation to punish those who treated them unfavourably (negative norm of reciprocity). Unexpectedly, relevance of the norm of positive reciprocity remained unaffected by mortality salience. Implications and limitations are discussed.

  20. Accumulation of DSBs in {gamma}-H2AX domains fuel chromosomal aberrations

    SciTech Connect

    Scherthan, H. Hieber, L.; Braselmann, H.; Meineke, V.; Zitzelsberger, H.

    2008-07-11

    DNA double strand breaks (DSBs) pose a severe hazard to the genome as erroneous rejoining of DSBs can lead to mutation and cancer. Here, we have investigated the correlation between X irradiation-induced {gamma}-H2AX foci, theoretically induced DSBs, and the minimal number of mis-rejoined DNA breaks (MNB) in irradiated lymphocytes obtained from two healthy humans by painting of the whole chromosome complement by spectral karyotyping. There were less {gamma}-H2AX foci/dose than theoretically expected, while misrepair, as expressed by MNB/{gamma}-H2AX focus, was similar at 0.5 and 1 Gy but 3.6-fold up at 3 Gy. Hence, our results suggest that X-ray-induced {gamma}-H2AX foci in G0 lymphocyte nuclei contain more than one DSB and that the increasing number of DSBs per {gamma}-H2AX repair factory lead to an increased rate of misrepair.

  1. Gadolinium-doped water cerenkov-based neutron and high energy gamma-ray detector and radiation portal monitoring system

    DOEpatents

    Dazeley, Steven A; Svoboda, Robert C; Bernstein, Adam; Bowden, Nathaniel

    2013-02-12

    A water Cerenkov-based neutron and high energy gamma ray detector and radiation portal monitoring system using water doped with a Gadolinium (Gd)-based compound as the Cerenkov radiator. An optically opaque enclosure is provided surrounding a detection chamber filled with the Cerenkov radiator, and photomultipliers are optically connected to the detect Cerenkov radiation generated by the Cerenkov radiator from incident high energy gamma rays or gamma rays induced by neutron capture on the Gd of incident neutrons from a fission source. The PMT signals are then used to determine time correlations indicative of neutron multiplicity events characteristic of a fission source.

  2. Reciprocity theory of gas surface interactions

    NASA Astrophysics Data System (ADS)

    Agbormbai, Adolf A.

    1989-11-01

    Since the Direct Simulation Monte Carlo (DSMC) method has established itself as a standard technique for numerically computing rarefied gas flows, it follows that to develop the theory of rarefied gas dynamics a framework for its fundamental microscopic processes needs to be formulated, i.e., intermolecular collisions and gas surface interactions, which lead to rigorous statistical models that can be utilized in the code. In this report attention is focussed on the mechanism of gas surface interactions. A reciprocity theory for it, which leads to models that can be utilized in the DSMC code, is formulated.

  3. Neural correlate of human reciprocity in social interactions.

    PubMed

    Sakaiya, Shiro; Shiraito, Yuki; Kato, Junko; Ide, Hiroko; Okada, Kensuke; Takano, Kouji; Kansaku, Kenji

    2013-01-01

    Reciprocity plays a key role maintaining cooperation in society. However, little is known about the neural process that underpins human reciprocity during social interactions. Our neuroimaging study manipulated partner identity (computer, human) and strategy (random, tit-for-tat) in repeated prisoner's dilemma games and investigated the neural correlate of reciprocal interaction with humans. Reciprocal cooperation with humans but exploitation of computers by defection was associated with activation in the left amygdala. Amygdala activation was also positively and negatively correlated with a preference change for human partners following tit-for-tat and random strategies, respectively. The correlated activation represented the intensity of positive feeling toward reciprocal and negative feeling toward non-reciprocal partners, and so reflected reciprocity in social interaction. Reciprocity in social interaction, however, might plausibly be misinterpreted and so we also examined the neural coding of insight into the reciprocity of partners. Those with and without insight revealed differential brain activation across the reward-related circuitry (i.e., the right middle dorsolateral prefrontal cortex and dorsal caudate) and theory of mind (ToM) regions [i.e., ventromedial prefrontal cortex (VMPFC) and precuneus]. Among differential activations, activation in the precuneus, which accompanied deactivation of the VMPFC, was specific to those without insight into human partners who were engaged in a tit-for-tat strategy. This asymmetric (de)activation might involve specific contributions of ToM regions to the human search for reciprocity. Consequently, the intensity of emotion attached to human reciprocity was represented in the amygdala, whereas insight into the reciprocity of others was reflected in activation across the reward-related and ToM regions. This suggests the critical role of mentalizing, which was not equated with reward expectation during social interactions.

  4. Neural correlate of human reciprocity in social interactions

    PubMed Central

    Sakaiya, Shiro; Shiraito, Yuki; Kato, Junko; Ide, Hiroko; Okada, Kensuke; Takano, Kouji; Kansaku, Kenji

    2013-01-01

    Reciprocity plays a key role maintaining cooperation in society. However, little is known about the neural process that underpins human reciprocity during social interactions. Our neuroimaging study manipulated partner identity (computer, human) and strategy (random, tit-for-tat) in repeated prisoner's dilemma games and investigated the neural correlate of reciprocal interaction with humans. Reciprocal cooperation with humans but exploitation of computers by defection was associated with activation in the left amygdala. Amygdala activation was also positively and negatively correlated with a preference change for human partners following tit-for-tat and random strategies, respectively. The correlated activation represented the intensity of positive feeling toward reciprocal and negative feeling toward non-reciprocal partners, and so reflected reciprocity in social interaction. Reciprocity in social interaction, however, might plausibly be misinterpreted and so we also examined the neural coding of insight into the reciprocity of partners. Those with and without insight revealed differential brain activation across the reward-related circuitry (i.e., the right middle dorsolateral prefrontal cortex and dorsal caudate) and theory of mind (ToM) regions [i.e., ventromedial prefrontal cortex (VMPFC) and precuneus]. Among differential activations, activation in the precuneus, which accompanied deactivation of the VMPFC, was specific to those without insight into human partners who were engaged in a tit-for-tat strategy. This asymmetric (de)activation might involve specific contributions of ToM regions to the human search for reciprocity. Consequently, the intensity of emotion attached to human reciprocity was represented in the amygdala, whereas insight into the reciprocity of others was reflected in activation across the reward-related and ToM regions. This suggests the critical role of mentalizing, which was not equated with reward expectation during social interactions

  5. Alternative energy efficient membrane bioreactor using reciprocating submerged membrane.

    PubMed

    Ho, J; Smith, S; Roh, H K

    2014-01-01

    A novel membrane bioreactor (MBR) pilot system, using membrane reciprocation instead of air scouring, was operated at constant high flux and daily fluctuating flux to demonstrate its application under peak and diurnal flow conditions. Low and stable transmembrane pressure was achieved at 40 l/m(2)/h (LMH) by use of repetitive membrane reciprocation. The results reveal that the inertial forces acting on the membrane fibers effectively propel foulants from the membrane surface. Reciprocation of the hollow fiber membrane is beneficial for the constant removal of solids that may build up on the membrane surface and inside the membrane bundle. The membrane reciprocation in the reciprocating MBR pilot consumed less energy than coarse air scouring used in conventional MBR systems. Specific energy consumption for the membrane reciprocation was 0.072 kWh/m(3) permeate produced at 40 LMH flux, which is 75% less than for a conventional air scouring system as reported in literature without consideration of energy consumption for biological aeration (0.29 kWh/m(3)). The daily fluctuating flux test confirmed that the membrane reciprocation is effective to handle fluctuating flux up to 50 LMH. The pilot-scale reciprocating MBR system successfully demonstrated that fouling can be controlled via 0.43 Hz membrane reciprocation with 44 mm or higher amplitude.

  6. Institutionalize Reciprocity to Overcome the Public Goods Provision Problem.

    PubMed

    Ozono, Hiroki; Kamijo, Yoshio; Shimizu, Kazumi

    2016-01-01

    Cooperation is fundamental to human societies, and one of the important paths for its emergence and maintenance is reciprocity. In prisoner's dilemma (PD) experiments, reciprocal strategies are often effective at attaining and maintaining high cooperation. In many public goods (PG) games or n-person PD experiments, however, reciprocal strategies are not successful at engendering cooperation. In the present paper, we attribute this difficulty to a coordination problem against free riding among reciprocators: Because it is difficult for the reciprocators to coordinate their behaviors against free riders, this may lead to inequality among players, which will demotivate them from cooperating in future rounds. We propose a new mechanism, institutionalized reciprocity (IR), which refers to embedding the reciprocal strategy as an institution (i.e., institutionalizing the reciprocal strategy). We experimentally demonstrate that IR can prevent groups of reciprocators from falling into coordination failure and achieve high cooperation in PG games. In conclusion, we argue that a natural extension of the present study will be to investigate the possibility of IR to serve as a collective punishment system.

  7. 32 CFR 634.16 - Reciprocal state-military action.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... DMV(s) per reciprocal agreements. In the absence of electronic communication technology, the... licensing authorities. Upon receipt of written or other official law enforcement communication relative...

  8. 32 CFR 634.16 - Reciprocal state-military action.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... DMV(s) per reciprocal agreements. In the absence of electronic communication technology, the... licensing authorities. Upon receipt of written or other official law enforcement communication relative...

  9. 32 CFR 634.16 - Reciprocal state-military action.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... DMV(s) per reciprocal agreements. In the absence of electronic communication technology, the... licensing authorities. Upon receipt of written or other official law enforcement communication relative...

  10. 32 CFR 634.16 - Reciprocal state-military action.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... DMV(s) per reciprocal agreements. In the absence of electronic communication technology, the... licensing authorities. Upon receipt of written or other official law enforcement communication relative...

  11. Alternative energy efficient membrane bioreactor using reciprocating submerged membrane.

    PubMed

    Ho, J; Smith, S; Roh, H K

    2014-01-01

    A novel membrane bioreactor (MBR) pilot system, using membrane reciprocation instead of air scouring, was operated at constant high flux and daily fluctuating flux to demonstrate its application under peak and diurnal flow conditions. Low and stable transmembrane pressure was achieved at 40 l/m(2)/h (LMH) by use of repetitive membrane reciprocation. The results reveal that the inertial forces acting on the membrane fibers effectively propel foulants from the membrane surface. Reciprocation of the hollow fiber membrane is beneficial for the constant removal of solids that may build up on the membrane surface and inside the membrane bundle. The membrane reciprocation in the reciprocating MBR pilot consumed less energy than coarse air scouring used in conventional MBR systems. Specific energy consumption for the membrane reciprocation was 0.072 kWh/m(3) permeate produced at 40 LMH flux, which is 75% less than for a conventional air scouring system as reported in literature without consideration of energy consumption for biological aeration (0.29 kWh/m(3)). The daily fluctuating flux test confirmed that the membrane reciprocation is effective to handle fluctuating flux up to 50 LMH. The pilot-scale reciprocating MBR system successfully demonstrated that fouling can be controlled via 0.43 Hz membrane reciprocation with 44 mm or higher amplitude. PMID:25521136

  12. Institutionalize Reciprocity to Overcome the Public Goods Provision Problem.

    PubMed

    Ozono, Hiroki; Kamijo, Yoshio; Shimizu, Kazumi

    2016-01-01

    Cooperation is fundamental to human societies, and one of the important paths for its emergence and maintenance is reciprocity. In prisoner's dilemma (PD) experiments, reciprocal strategies are often effective at attaining and maintaining high cooperation. In many public goods (PG) games or n-person PD experiments, however, reciprocal strategies are not successful at engendering cooperation. In the present paper, we attribute this difficulty to a coordination problem against free riding among reciprocators: Because it is difficult for the reciprocators to coordinate their behaviors against free riders, this may lead to inequality among players, which will demotivate them from cooperating in future rounds. We propose a new mechanism, institutionalized reciprocity (IR), which refers to embedding the reciprocal strategy as an institution (i.e., institutionalizing the reciprocal strategy). We experimentally demonstrate that IR can prevent groups of reciprocators from falling into coordination failure and achieve high cooperation in PG games. In conclusion, we argue that a natural extension of the present study will be to investigate the possibility of IR to serve as a collective punishment system. PMID:27248493

  13. Institutionalize Reciprocity to Overcome the Public Goods Provision Problem

    PubMed Central

    2016-01-01

    Cooperation is fundamental to human societies, and one of the important paths for its emergence and maintenance is reciprocity. In prisoner’s dilemma (PD) experiments, reciprocal strategies are often effective at attaining and maintaining high cooperation. In many public goods (PG) games or n-person PD experiments, however, reciprocal strategies are not successful at engendering cooperation. In the present paper, we attribute this difficulty to a coordination problem against free riding among reciprocators: Because it is difficult for the reciprocators to coordinate their behaviors against free riders, this may lead to inequality among players, which will demotivate them from cooperating in future rounds. We propose a new mechanism, institutionalized reciprocity (IR), which refers to embedding the reciprocal strategy as an institution (i.e., institutionalizing the reciprocal strategy). We experimentally demonstrate that IR can prevent groups of reciprocators from falling into coordination failure and achieve high cooperation in PG games. In conclusion, we argue that a natural extension of the present study will be to investigate the possibility of IR to serve as a collective punishment system. PMID:27248493

  14. Reciprocating piston pump system with screw drive

    NASA Technical Reports Server (NTRS)

    Perkins, Gerald S. (Inventor); Moore, Nicholas R. (Inventor)

    1981-01-01

    A pump system of the reciprocating piston type is described, which facilitates direct motor drive and cylinder sealing. A threaded middle potion of the piston is engaged by a nut connected to rotate with the rotor of an electric motor, in a manner that minimizes loading on the rotor by the use of a coupling that transmits torque to the nut but permits it to shift axially and radially with respect to the rotor. The nut has a threaded hydrostatic bearing for engaging the threaded piston portion, with an oil-carrying groove in the nut being interrupted. A fluid emitting seal located at the entrance to each cylinder, can serve to center the piston within the cylinder, wash the piston, and to aid in sealing. The piston can have a long stroke to diameter ratio to minimize reciprocations and wear on valves at high pressures. The voltage applied to the motor can be reversed prior to the piston reaching the end of its stroke, to permit pressure on the piston to aid in reversing the motor.

  15. Lookup tables to compute high energy cosmic ray induced atmospheric ionization and changes in atmospheric chemistry

    SciTech Connect

    Atri, Dimitra; Melott, Adrian L.; Thomas, Brian C. E-mail: melott@ku.edu

    2010-05-01

    A variety of events such as gamma-ray bursts and supernovae may expose the Earth to an increased flux of high-energy cosmic rays, with potentially important effects on the biosphere. Existing atmospheric chemistry software does not have the capability of incorporating the effects of substantial cosmic ray flux above 10 GeV. An atmospheric code, the NASA-Goddard Space Flight Center two-dimensional (latitude, altitude) time-dependent atmospheric model (NGSFC), is used to study atmospheric chemistry changes. Using CORSIKA, we have created tables that can be used to compute high energy cosmic ray (10 GeV–1 PeV) induced atmospheric ionization and also, with the use of the NGSFC code, can be used to simulate the resulting atmospheric chemistry changes. We discuss the tables, their uses, weaknesses, and strengths.

  16. Surface modification by γ-ray-induced grafting of PDMAEMA/PEGMEMA onto PE films

    NASA Astrophysics Data System (ADS)

    Titaux, G. A.; Contreras-García, A.; Bucio, E.

    2009-07-01

    Radiation grafting of poly[2-(dimethylamino) ethyl methacrylate] (PDMAEMA) and poly(ethylene glycol) methyl ether methacrylate (PEGMEMA) onto polyethylene (PE) films was synthesized using gamma radiation from a 60Co source. PE was modified by the PDMAEMA and PEGMEMA by pre-irradiation and one-step method. Grafting as a function of the pre-irradiation dose between 50 and 200 kGy, dose rate of 9 kGy h -1, and monomer concentration 50% of PDMAEMA/PEGMEMA (1/1) in toluene. The characterization of the graft copolymer obtained was carried out by FTIR-ATR, TGA, and DSC. Stimuli-responsive behavior and critical pH point were studied by swelling in water, pH and thermo-responsive films of PE-g-(DMAEMA/PEGMEMA) presented a lower critical solution temperature (LCST) of 55 °C and critical pH point around 8.5.

  17. Gamma Knife

    MedlinePlus

    ... results are sent to the Gamma Knife®'s planning computer system. Together, physicians ( radiation oncologists and neurosurgeons) and medical physicists delineate targets and normal anatomical structures. They use a planning computer program to determine the exact spatial relationship between ...

  18. Gamma watermarking

    DOEpatents

    Ishikawa, Muriel Y.; Wood, Lowell L.; Lougheed, Ronald W.; Moody, Kenton J.; Wang, Tzu-Fang

    2004-05-25

    A covert, gamma-ray "signature" is used as a "watermark" for property identification. This new watermarking technology is based on a unique steganographic or "hidden writing" digital signature, implemented in tiny quantities of gamma-ray-emitting radioisotopic material combinations, generally covertly emplaced on or within an object. This digital signature may be readily recovered at distant future times, by placing a sensitive, high energy-resolution gamma-ray detecting instrument reasonably precisely over the location of the watermark, which location may be known only to the object's owner; however, the signature is concealed from all ordinary detection means because its exceedingly low level of activity is obscured by the natural radiation background (including the gamma radiation naturally emanating from the object itself, from cosmic radiation and material surroundings, from human bodies, etc.). The "watermark" is used in object-tagging for establishing object identity, history or ownership. It thus may serve as an aid to law enforcement officials in identifying stolen property and prosecuting theft thereof. Highly effective, potentially very low cost identification-on demand of items of most all types is thus made possible.

  19. Similarity and Reciprocity in the Friendships of Elementary School Children.

    ERIC Educational Resources Information Center

    Clark, M. L.; Drewry, Debra L.

    1985-01-01

    Investigated the effect of similarity and reciprocity on dyadic friendship choices in third- and sixth-grade students. Reciprocal (mutual) friendships were more similar in proximity, popularity, and self-concept than those in nonreciprocal (nonmutual) dyads. Results are discussed in relation to the interpersonal attraction theories. (Author/DST)

  20. 32 CFR 148.1 - Intergency reciprocal acceptance .

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... reciprocal acceptance of security policies and procedures for approving, accrediting, and maintaining the... AND CIVILIAN NATIONAL POLICY AND IMPLEMENTATION OF RECIPROCITY OF FACILITIES National Policy on... security systems, preserve vitality of the U.S. industrial base, and advance national security objectives....

  1. Structural Implications of Reciprocal Exchange: A Power-Dependence Approach

    ERIC Educational Resources Information Center

    Bonacich, Phillip; Bienenstock, Elisa Jayne

    2009-01-01

    This paper presents and tests a general model to predict emergent exchange patterns and power differences in reciprocal exchange networks when individual actors follow the norm of reciprocity. With an interesting qualification, the experimental results reported here support the power-dependence approach (Emerson 1972a, b): those who acquire the…

  2. 32 CFR 148.1 - Interagency reciprocal acceptance .

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... reciprocal acceptance of security policies and procedures for approving, accrediting, and maintaining the..., MILITARY AND CIVILIAN NATIONAL POLICY AND IMPLEMENTATION OF RECIPROCITY OF FACILITIES National Policy on... security systems, preserve vitality of the U.S. industrial base, and advance national security objectives....

  3. 32 CFR 148.1 - Interagency reciprocal acceptance .

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... reciprocal acceptance of security policies and procedures for approving, accrediting, and maintaining the..., MILITARY AND CIVILIAN NATIONAL POLICY AND IMPLEMENTATION OF RECIPROCITY OF FACILITIES National Policy on... security systems, preserve vitality of the U.S. industrial base, and advance national security objectives....

  4. 32 CFR 148.1 - Interagency reciprocal acceptance .

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... reciprocal acceptance of security policies and procedures for approving, accrediting, and maintaining the..., MILITARY AND CIVILIAN NATIONAL POLICY AND IMPLEMENTATION OF RECIPROCITY OF FACILITIES National Policy on... security systems, preserve vitality of the U.S. industrial base, and advance national security objectives....

  5. Symmetry-based reciprocity: evolutionary constraints on a proximate mechanism

    PubMed Central

    Campennì, Marco

    2016-01-01

    Background. While the evolution of reciprocal cooperation has attracted an enormous attention, the proximate mechanisms underlying the ability of animals to cooperate reciprocally are comparatively neglected. Symmetry-based reciprocity is a hypothetical proximate mechanism that has been suggested to be widespread among cognitively unsophisticated animals. Methods. We developed two agent-based models of symmetry-based reciprocity (one relying on an arbitrary tag and the other on interindividual proximity) and tested their ability both to reproduce significant emergent features of cooperation in group living animals and to promote the evolution of cooperation. Results. Populations formed by agents adopting symmetry-based reciprocity showed differentiated “social relationships” and a positive correlation between cooperation given and received: two common aspects of animal cooperation. However, when reproduction and selection across multiple generations were added to the models, agents adopting symmetry-based reciprocity were outcompeted by selfish agents that never cooperated. Discussion. In order to evolve, hypothetical proximate mechanisms must be able to stand competition from alternative strategies. While the results of our simulations require confirmation using analytical methods, we provisionally suggest symmetry-based reciprocity is to be abandoned as a possible proximate mechanism underlying the ability of animals to reciprocate cooperative interactions. PMID:26998412

  6. Symmetry-based reciprocity: evolutionary constraints on a proximate mechanism.

    PubMed

    Campennì, Marco; Schino, Gabriele

    2016-01-01

    Background. While the evolution of reciprocal cooperation has attracted an enormous attention, the proximate mechanisms underlying the ability of animals to cooperate reciprocally are comparatively neglected. Symmetry-based reciprocity is a hypothetical proximate mechanism that has been suggested to be widespread among cognitively unsophisticated animals. Methods. We developed two agent-based models of symmetry-based reciprocity (one relying on an arbitrary tag and the other on interindividual proximity) and tested their ability both to reproduce significant emergent features of cooperation in group living animals and to promote the evolution of cooperation. Results. Populations formed by agents adopting symmetry-based reciprocity showed differentiated "social relationships" and a positive correlation between cooperation given and received: two common aspects of animal cooperation. However, when reproduction and selection across multiple generations were added to the models, agents adopting symmetry-based reciprocity were outcompeted by selfish agents that never cooperated. Discussion. In order to evolve, hypothetical proximate mechanisms must be able to stand competition from alternative strategies. While the results of our simulations require confirmation using analytical methods, we provisionally suggest symmetry-based reciprocity is to be abandoned as a possible proximate mechanism underlying the ability of animals to reciprocate cooperative interactions.

  7. Strong reciprocity is not uncommon in the "wild".

    PubMed

    Runciman, W G

    2012-02-01

    Guala is right to draw attention to the difficulty of extrapolating from the experimental evidence for weak or strong reciprocity to what is observed in the "wild." However, there may be more strong reciprocity in real-world communities than he allows for, as strikingly illustrated in the example of the Mafia.

  8. Proximate and ultimate causes of punishment and strong reciprocity.

    PubMed

    Barclay, Pat

    2012-02-01

    While admirable, Guala's discussion of reciprocity suffers from a confusion between proximate causes (psychological mechanisms triggering behaviour) and ultimate causes (evolved function of those psychological mechanisms). Because much work on "strong reciprocity" commits this error, I clarify the difference between proximate and ultimate causes of cooperation and punishment. I also caution against hasty rejections of "wide readings" of experimental evidence.

  9. 2005 Reciprocity Agreements and Other Student Exchange Options

    ERIC Educational Resources Information Center

    Washington Higher Education Coordinating Board, 2005

    2005-01-01

    The Higher Education Coordinating Board (HECB) is required by state law to report to the governor and legislature every two years on the status of Washington's state-level reciprocity agreements with Idaho, Oregon, and British Columbia. Reciprocity agreements allow some Washington students to attend public colleges in other states and pay lower…

  10. Instructional Guidance in Reciprocal Peer Tutoring With Task Cards

    ERIC Educational Resources Information Center

    Iserbyt, Peter; Elen, Jan; Behets, Daniel

    2010-01-01

    This article addresses the issue of instructional guidance in reciprocal peer tutoring with task cards as learning tools. Eighty-six Kinesiology students (age 17-19 years) were randomized across four reciprocal peer tutoring settings, differing in quality and quantity of guidance, to learn Basic Life Support (BLS) with task cards. The separate and…

  11. An Analysis of Direct Reciprocal Borrowing among Quebec University Libraries

    ERIC Educational Resources Information Center

    Duy, Joanna C.; Lariviere, Vincent

    2013-01-01

    An analysis of Quebec academic libraries' direct reciprocal borrowing statistics from 2005 to 2010 reveals that the physical distance separating universities plays an important role in determining the amount of direct reciprocal borrowing activity conducted between institutions. Significant statistical correlations were also seen between the…

  12. Using Excel's Matrix Operations to Facilitate Reciprocal Cost Allocations

    ERIC Educational Resources Information Center

    Leese, Wallace R.; Kizirian, Tim

    2009-01-01

    The reciprocal method of service department cost allocation requires linear equations to be solved simultaneously. These computations are often so complex as to cause the abandonment of the reciprocal method in favor of the less sophisticated direct or step-down methods. Here is a short example demonstrating how Excel's sometimes unknown matrix…

  13. Lack of Acceptance of Reciprocity Norms in Preschool Children.

    ERIC Educational Resources Information Center

    Berndt, Thomas J.

    1979-01-01

    Two studies investigated preschool children's acceptance of the reciprocity norms that allow retaliation and that require returning favors. Children viewed cartoons that portrayed animal puppets involved in reciprocal or nonreciprocal aggressive and prosocial behavior. They were then asked to evaluate the actor in each cartoon as "good" or "bad"…

  14. Reciprocal Mentorship: An Effective Support for Online Instructors

    ERIC Educational Resources Information Center

    Gabriel, Martha A.; Kaufield, Kandra J.

    2008-01-01

    This article presents a reciprocal model of mentoring as an alternative approach to more traditional mentoring models. A mentor, experienced with online course delivery and pedagogy, worked with six online instructors over two academic terms within a reciprocal mentorship model. This model was designed to build a collaborative learning…

  15. 47 CFR 51.711 - Symmetrical reciprocal compensation.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 47 Telecommunication 3 2012-10-01 2012-10-01 false Symmetrical reciprocal compensation. 51.711 Section 51.711 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) COMMON CARRIER SERVICES... Traffic § 51.711 Symmetrical reciprocal compensation. (a) Rates for transport and termination of...

  16. Reciprocal Relationships between Math Self-Concept and Math Anxiety

    ERIC Educational Resources Information Center

    Ahmed, Wondimu; Minnaert, Alexander; Kuyper, Hans; van der Werf, Greetje

    2012-01-01

    The present study examined the reciprocal relationships between self-concept and anxiety in mathematics. A sample of 495 grade 7 students (51% girls) completed self-report measures assessing self-concept and anxiety three times in a school year. Structural equation modeling was used to test a cross-lagged panel model of reciprocal effects between…

  17. Symmetry-based reciprocity: evolutionary constraints on a proximate mechanism.

    PubMed

    Campennì, Marco; Schino, Gabriele

    2016-01-01

    Background. While the evolution of reciprocal cooperation has attracted an enormous attention, the proximate mechanisms underlying the ability of animals to cooperate reciprocally are comparatively neglected. Symmetry-based reciprocity is a hypothetical proximate mechanism that has been suggested to be widespread among cognitively unsophisticated animals. Methods. We developed two agent-based models of symmetry-based reciprocity (one relying on an arbitrary tag and the other on interindividual proximity) and tested their ability both to reproduce significant emergent features of cooperation in group living animals and to promote the evolution of cooperation. Results. Populations formed by agents adopting symmetry-based reciprocity showed differentiated "social relationships" and a positive correlation between cooperation given and received: two common aspects of animal cooperation. However, when reproduction and selection across multiple generations were added to the models, agents adopting symmetry-based reciprocity were outcompeted by selfish agents that never cooperated. Discussion. In order to evolve, hypothetical proximate mechanisms must be able to stand competition from alternative strategies. While the results of our simulations require confirmation using analytical methods, we provisionally suggest symmetry-based reciprocity is to be abandoned as a possible proximate mechanism underlying the ability of animals to reciprocate cooperative interactions. PMID:26998412

  18. Transient nature of cooperation by pay-it-forward reciprocity

    PubMed Central

    Horita, Yutaka; Takezawa, Masanori; Kinjo, Takuji; Nakawake, Yo; Masuda, Naoki

    2016-01-01

    Humans often forward kindness received from others to strangers, a phenomenon called the upstream or pay-it-forward indirect reciprocity. Some field observations and laboratory experiments found evidence of pay-it-forward reciprocity in which chains of cooperative acts persist in social dilemma situations. Theoretically, however, cooperation based on pay-it-forward reciprocity is not sustainable. We carried out laboratory experiments of a pay-it-forward indirect reciprocity game (i.e., chained gift-giving game) on a large scale in terms of group size and time. We found that cooperation consistent with pay-it-forward reciprocity occurred only in a first few decisions per participant and that cooperation originated from inherent pro-sociality of individuals. In contrast, the same groups of participants showed persisting chains of cooperation in a different indirect reciprocity game in which participants earned reputation by cooperating. Our experimental results suggest that pay-it-forward reciprocity is transient and disappears when a person makes decisions repeatedly, whereas the reputation-based reciprocity is stable in the same situation. PMID:26786178

  19. 76 FR 8661 - Airworthiness Directives; Lycoming Engines, Fuel Injected Reciprocating Engines

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-02-15

    ...-14-07, Amendment 39-15602 (73 FR 39574), for certain fuel injected reciprocating engines manufactured... Directives; Lycoming Engines, Fuel Injected Reciprocating Engines AGENCY: Federal Aviation Administration... airworthiness directive (AD) that applies to certain fuel injected reciprocating engines manufactured...

  20. Does food sharing in vampire bats demonstrate reciprocity?

    PubMed

    Carter, Gerald; Wilkinson, Gerald

    2013-11-01

    Claims of reciprocity (or reciprocal altruism) in animal societies often ignite controversy because authors disagree over definitions, naturalistic studies tend to demonstrate correlation not causation, and controlled experiments often involve artificial conditions. Food sharing among common vampire bats has been a classic textbook example of reciprocity, but this conclusion has been contested by alternative explanations. Here, we review factors that predict food sharing in vampire bats based on previously published and unpublished data, validate previous published results with more precise relatedness estimates, and describe current evidence for and against alternative explanations for its evolutionary stability. Although correlational evidence indicates a role for both direct and indirect fitness benefits, unequivocally demonstrating reciprocity in vampire bats still requires testing if and how bats respond to non-reciprocation.

  1. Does food sharing in vampire bats demonstrate reciprocity?

    PubMed

    Carter, Gerald; Wilkinson, Gerald

    2013-11-01

    Claims of reciprocity (or reciprocal altruism) in animal societies often ignite controversy because authors disagree over definitions, naturalistic studies tend to demonstrate correlation not causation, and controlled experiments often involve artificial conditions. Food sharing among common vampire bats has been a classic textbook example of reciprocity, but this conclusion has been contested by alternative explanations. Here, we review factors that predict food sharing in vampire bats based on previously published and unpublished data, validate previous published results with more precise relatedness estimates, and describe current evidence for and against alternative explanations for its evolutionary stability. Although correlational evidence indicates a role for both direct and indirect fitness benefits, unequivocally demonstrating reciprocity in vampire bats still requires testing if and how bats respond to non-reciprocation. PMID:24505498

  2. Ultimate and proximate mechanisms of reciprocal altruism in rats.

    PubMed

    Dolivo, Vassilissa; Rutte, Claudia; Taborsky, Michael

    2016-09-01

    The reciprocal exchange of goods and services among social partners is a conundrum in evolutionary biology because of its proneness to cheating, but also the behavioral and cognitive mechanisms involved in such mutual cooperation are hotly debated. Extreme viewpoints range from the assumption that, at the proximate level, observed cases of "direct reciprocity" can be merely explained by basic instrumental and Pavlovian association processes, to the other extreme implying that "cultural factors" must be involved, as is often attributed to reciprocal cooperation among humans. Here we argue that neither one nor the other extreme conception is likely to explain proximate mechanisms underlying reciprocal altruism in animals. In particular, we outline that Pavlovian association processes are not sufficient to explain the documented reciprocal cooperation among Norway rats, as has been recently argued. PMID:27495930

  3. Reciprocal and unidirectional scattering of parity-time symmetric structures

    PubMed Central

    Jin, L.; Zhang, X. Z.; Zhang, G.; Song, Z.

    2016-01-01

    Parity-time symmetry is of great interest. The reciprocal and unidirectional features are intriguing besides the symmetry phase transition. Recently, the reciprocal transmission, unidirectional reflectionless and invisibility are intensively studied. Here, we show the reciprocal reflection/transmission in -symmetric system is closely related to the type of symmetry, that is, the axial (reflection) symmetry leads to reciprocal reflection (transmission). The results are further elucidated by studying the scattering of rhombic ring form coupled resonators with enclosed synthetic magnetic flux. The nonreciprocal phase shift induced by the magnetic flux and gain/loss break the parity and time-reversal symmetry but keep the parity-time symmetry. The reciprocal reflection (transmission) and unidirectional transmission (reflection) are found in the axial (reflection) -symmetric ring centre. The explorations of symmetry and asymmetry from symmetry may shed light on novel one-way optical devices and application of -symmetric metamaterials. PMID:26876806

  4. Permanent junctional reciprocating tachycardia in a dog.

    PubMed

    Santilli, Roberto A; Santos, Luis F N; Perego, Manuela

    2013-09-01

    A 5-year-old male English Bulldog was presented with a 1-year history of paroxysmal supraventricular tachycardia (SVT) partially responsive to amiodarone. At admission the surface ECG showed sustained runs of a narrow QRS complex tachycardia, with a ventricular cycle length (R-R interval) of 260 ms, alternating with periods of sinus rhythm. Endocardial mapping identified the electrogenic mechanism of the SVT as a circus movement tachycardia with retrograde and decremental conduction along a concealed postero-septal atrioventricular pathway (AP) and anterograde conduction along the atrioventricular node. These characteristics were indicative of a permanent junctional reciprocating tachycardia (PJRT). Radiofrequency catheter ablation of the AP successfully terminated the PJRT, with no recurrence of tachycardia on Holter monitoring at 12 months follow-up.

  5. Linkage map construction involving a reciprocal translocation.

    PubMed

    Farré, A; Benito, I Lacasa; Cistué, L; de Jong, J H; Romagosa, I; Jansen, J

    2011-03-01

    This paper is concerned with a novel statistical-genetic approach for the construction of linkage maps in populations obtained from reciprocal translocation heterozygotes of barley (Hordeum vulgare L.). Using standard linkage analysis, translocations usually lead to 'pseudo-linkage': the mixing up of markers from the chromosomes involved in the translocation into a single linkage group. Close to the translocation breakpoints recombination is severely suppressed and, as a consequence, ordering markers in those regions is not feasible. The novel strategy presented in this paper is based on (1) disentangling the "pseudo-linkage" using principal coordinate analysis, (2) separating individuals into translocated types and normal types and (3) separating markers into those close to and those more distant from the translocation breakpoints. The methods make use of a consensus map of the species involved. The final product consists of integrated linkage maps of the distal parts of the chromosomes involved in the translocation.

  6. Fluid flow within reciprocating-engine cylinders

    NASA Astrophysics Data System (ADS)

    Awn, A. G.; Spalding, D. B.

    The present investigation has the objective to demonstrate a method of predicting the flow within reciprocating-engine cylinders. The application of this approach can help the engine designer to increase the combustion efficiency and to reduce pollution. The considered method employs finite-difference equations similar to those used by Watkins (1973) and Chong et. al. (1976). The equations are, however, solved by a somewhat different method, and, in addition, an interface-tracking procedure is employed. The numerical procedure is further extended to investigate the scavenging flows in two-stroke engines. One problem studied in the investigation is concerned with the prediction of the velocity field in an engine cylinder during the harmonic motion of a flat-topped piston. A second problem involves the study of the flow behavior during the scavenging cycle in two-stroke engine cyclinders.

  7. Non-reciprocal ultrafast laser writing

    NASA Astrophysics Data System (ADS)

    Yang, Weijia; Kazansky, Peter G.; Svirko, Yuri P.

    2008-02-01

    Photosensitivity is a material property that is relevant to many phenomena and applications, from photosynthesis and photography to optical data storage and ultrafast laser writing. It was commonly thought that, in a homogeneous medium, photosensitivity and the corresponding light-induced material modifications do not change on reversing the direction of light propagation. Here we demonstrate that when the direction of the femtosecond laser beam is reversed from the +z to -z direction, the structures written in LiNbO3 crystal when translating the beam along the +y and -y directions are mirrored. In a non-centrosymmetric medium, modification of the material can therefore differ for light propagating in opposite directions. This is the first evidence of a new optical phenomenon of non-reciprocal photosensitivity. We interpret this effect in terms of light pressure and associated heat flow, resulting in a temperature gradient in homogeneous media without inversion symmetry under uniform intense irradiation.

  8. Balancing mechanism for reciprocating piston engine

    SciTech Connect

    Murata, N.; Ogino, T.

    1987-04-14

    This patent describes a balancing mechanism for a reciprocating piston internal combustion engine which includes a cylinder, a piston reciprocatable in the cylinder, a crankcase, a crankshaft mounted in the crankshaft, a crankpin connected to the piston, and a pair of crank arms bridging the crankshaft and crankpin. The crank arms and crankpin rotate with the crankshaft during operation and form a rotating mass. The balancing mechanism comprises at least one rotating counterweight attached to and rotating with the crankshaft, and eccentric journal means on the crankshaft adjacent the crank arms, rotating with the crankshaft. The journal means has an axis spaced to the side of the crankshaft axis which is opposite from the crankpin. The rotating counterweight and the eccentric journal means counterbalancing the rotating mass.

  9. Dynamic reciprocity in the wound microenvironment.

    PubMed

    Schultz, Gregory S; Davidson, Jeffrey M; Kirsner, Robert S; Bornstein, Paul; Herman, Ira M

    2011-01-01

    Here, we define dynamic reciprocity (DR) as an ongoing, bidirectional interaction among cells and their surrounding microenvironment. In this review, we posit that DR is especially meaningful during wound healing as the DR-driven biochemical, biophysical, and cellular responses to injury play pivotal roles in regulating tissue regenerative responses. Such cell-extracellular matrix interactions not only guide and regulate cellular morphology, but also cellular differentiation, migration, proliferation, and survival during tissue development, including, e.g., embryogenesis, angiogenesis, as well as during pathologic processes including cancer, diabetes, hypertension, and chronic wound healing. Herein, we examine DR within the wound microenvironment while considering specific examples across acute and chronic wound healing. This review also considers how a number of hypotheses that attempt to explain chronic wound pathophysiology may be understood within the DR framework. The implications of applying the principles of DR to optimize wound care practice and future development of innovative wound healing therapeutics are also briefly considered.

  10. Sleep and exercise: a reciprocal issue?

    PubMed

    Chennaoui, Mounir; Arnal, Pierrick J; Sauvet, Fabien; Léger, Damien

    2015-04-01

    Sleep and exercise influence each other through complex, bilateral interactions that involve multiple physiological and psychological pathways. Physical activity is usually considered as beneficial in aiding sleep although this link may be subject to multiple moderating factors such as sex, age, fitness level, sleep quality and the characteristics of the exercise (intensity, duration, time of day, environment). It is therefore vital to improve knowledge in fundamental physiology in order to understand the benefits of exercise on the quantity and quality of sleep in healthy subjects and patients. Conversely, sleep disturbances could also impair a person's cognitive performance or their capacity for exercise and increase the risk of exercise-induced injuries either during extreme and/or prolonged exercise or during team sports. This review aims to describe the reciprocal fundamental physiological effects linking sleep and exercise in order to improve the pertinent use of exercise in sleep medicine and prevent sleep disorders in sportsmen.

  11. Thermal Powered Reciprocating-Force Motor

    NASA Technical Reports Server (NTRS)

    Tatum, III, Paul F. (Inventor); McDow Elliott, Amelia (Inventor)

    2015-01-01

    A thermal-powered reciprocating-force motor includes a shutter switchable between a first position that passes solar energy and a second position that blocks solar energy. A shape memory alloy (SMA) actuator is coupled to the shutter to control switching thereof between the shutter's first and second position. The actuator is positioned with respect to the shutter such that (1) solar energy impinges on the SMA when the shutter is in its first position so that the SMA experiences contraction in length until the shutter is switched to its second position, and (2) solar energy is impeded from impingement on the SMA when the shutter is in its second position so that the SMA experiences extension in length. Elastic members coupled to the actuator apply a force to the SMA that aids in its extension in length until the shutter is switched to its first position.

  12. Advanced Natural Gas Reciprocating Engine(s)

    SciTech Connect

    Kwok, Doris; Boucher, Cheryl

    2009-09-30

    Energy independence and fuel savings are hallmarks of the nation’s energy strategy. The advancement of natural gas reciprocating engine power generation technology is critical to the nation’s future. A new engine platform that meets the efficiency, emissions, fuel flexibility, cost and reliability/maintainability targets will enable American manufacturers to have highly competitive products that provide substantial environmental and economic benefits in the US and in international markets. Along with Cummins and Waukesha, Caterpillar participated in a multiyear cooperative agreement with the Department of Energy to create a 50% efficiency natural gas powered reciprocating engine system with a 95% reduction in NOx emissions by the year 2013. This platform developed under this agreement will be a significant contributor to the US energy strategy and will enable gas engine technology to remain a highly competitive choice, meeting customer cost of electricity targets, and regulatory environmental standard. Engine development under the Advanced Reciprocating Engine System (ARES) program was divided into phases, with the ultimate goal being approached in a series of incremental steps. This incremental approach would promote the commercialization of ARES technologies as soon as they emerged from development and would provide a technical and commercial foundation of later-developing technologies. Demonstrations of the Phase I and Phase II technology were completed in 2004 and 2008, respectively. Program tasks in Phase III included component and system development and testing from 2009-2012. Two advanced ignition technology evaluations were investigated under the ARES program: laser ignition and distributed ignition (DIGN). In collaboration with Colorado State University (CSU), a laser ignition system was developed to provide ignition at lean burn and high boost conditions. Much work has been performed in Caterpillar’s DIGN program under the ARES program. This work

  13. Clustering in large networks does not promote upstream reciprocity.

    PubMed

    Masuda, Naoki

    2011-01-01

    Upstream reciprocity (also called generalized reciprocity) is a putative mechanism for cooperation in social dilemma situations with which players help others when they are helped by somebody else. It is a type of indirect reciprocity. Although upstream reciprocity is often observed in experiments, most theories suggest that it is operative only when players form short cycles such as triangles, implying a small population size, or when it is combined with other mechanisms that promote cooperation on their own. An expectation is that real social networks, which are known to be full of triangles and other short cycles, may accommodate upstream reciprocity. In this study, I extend the upstream reciprocity game proposed for a directed cycle by Boyd and Richerson to the case of general networks. The model is not evolutionary and concerns the conditions under which the unanimity of cooperative players is a Nash equilibrium. I show that an abundance of triangles or other short cycles in a network does little to promote upstream reciprocity. Cooperation is less likely for a larger population size even if triangles are abundant in the network. In addition, in contrast to the results for evolutionary social dilemma games on networks, scale-free networks lead to less cooperation than networks with a homogeneous degree distribution.

  14. The evolution of generalized reciprocity on social interaction networks.

    PubMed

    van Doorn, Gerrit Sander; Taborsky, Michael

    2012-03-01

    Generalized reciprocity (help anyone, if helped by someone) is a minimal strategy capable of supporting cooperation between unrelated individuals. Its simplicity makes it an attractive model to explain the evolution of reciprocal altruism in animals that lack the information or cognitive skills needed for other types of reciprocity. Yet, generalized reciprocity is anonymous and thus defenseless against exploitation by defectors. Recognizing that animals hardly ever interact randomly, we investigate whether social network structure can mitigate this vulnerability. Our results show that heterogeneous interaction patterns strongly support the evolution of generalized reciprocity. The future probability of being rewarded for an altruistic act is inversely proportional to the average connectivity of the social network when cooperators are rare. Accordingly, sparse networks are conducive to the invasion of reciprocal altruism. Moreover, the evolutionary stability of cooperation is enhanced by a modular network structure. Communities of reciprocal altruists are protected against exploitation, because modularity increases the mean access time, that is, the average number of steps that it takes for a random walk on the network to reach a defector. Sparseness and community structure are characteristic properties of vertebrate social interaction patterns, as illustrated by network data from natural populations ranging from fish to primates.

  15. Near optimal graphene terahertz non-reciprocal isolator.

    PubMed

    Tamagnone, Michele; Moldovan, Clara; Poumirol, Jean-Marie; Kuzmenko, Alexey B; Ionescu, Adrian M; Mosig, Juan R; Perruisseau-Carrier, Julien

    2016-04-06

    Isolators, or optical diodes, are devices enabling unidirectional light propagation by using non-reciprocal optical materials, namely materials able to break Lorentz reciprocity. The realization of isolators at terahertz frequencies is a very important open challenge made difficult by the intrinsically lossy propagation of terahertz radiation in current non-reciprocal materials. Here we report the design, fabrication and measurement of a terahertz non-reciprocal isolator for circularly polarized waves based on magnetostatically biased monolayer graphene, operating in reflection. The device exploits the non-reciprocal optical conductivity of graphene and, in spite of its simple design, it exhibits almost 20 dB of isolation and only 7.5 dB of insertion loss at 2.9 THz. Operation with linearly polarized light can be achieved using quarter-wave plates as polarization converters. These results demonstrate the superiority of graphene with respect to currently used terahertz non-reciprocal materials and pave the way to a novel class of optimal non-reciprocal devices.

  16. Near optimal graphene terahertz non-reciprocal isolator

    PubMed Central

    Tamagnone, Michele; Moldovan, Clara; Poumirol, Jean-Marie; Kuzmenko, Alexey B.; Ionescu, Adrian M.; Mosig, Juan R.; Perruisseau-Carrier, Julien

    2016-01-01

    Isolators, or optical diodes, are devices enabling unidirectional light propagation by using non-reciprocal optical materials, namely materials able to break Lorentz reciprocity. The realization of isolators at terahertz frequencies is a very important open challenge made difficult by the intrinsically lossy propagation of terahertz radiation in current non-reciprocal materials. Here we report the design, fabrication and measurement of a terahertz non-reciprocal isolator for circularly polarized waves based on magnetostatically biased monolayer graphene, operating in reflection. The device exploits the non-reciprocal optical conductivity of graphene and, in spite of its simple design, it exhibits almost 20 dB of isolation and only 7.5 dB of insertion loss at 2.9 THz. Operation with linearly polarized light can be achieved using quarter-wave plates as polarization converters. These results demonstrate the superiority of graphene with respect to currently used terahertz non-reciprocal materials and pave the way to a novel class of optimal non-reciprocal devices. PMID:27048760

  17. Near optimal graphene terahertz non-reciprocal isolator.

    PubMed

    Tamagnone, Michele; Moldovan, Clara; Poumirol, Jean-Marie; Kuzmenko, Alexey B; Ionescu, Adrian M; Mosig, Juan R; Perruisseau-Carrier, Julien

    2016-01-01

    Isolators, or optical diodes, are devices enabling unidirectional light propagation by using non-reciprocal optical materials, namely materials able to break Lorentz reciprocity. The realization of isolators at terahertz frequencies is a very important open challenge made difficult by the intrinsically lossy propagation of terahertz radiation in current non-reciprocal materials. Here we report the design, fabrication and measurement of a terahertz non-reciprocal isolator for circularly polarized waves based on magnetostatically biased monolayer graphene, operating in reflection. The device exploits the non-reciprocal optical conductivity of graphene and, in spite of its simple design, it exhibits almost 20 dB of isolation and only 7.5 dB of insertion loss at 2.9 THz. Operation with linearly polarized light can be achieved using quarter-wave plates as polarization converters. These results demonstrate the superiority of graphene with respect to currently used terahertz non-reciprocal materials and pave the way to a novel class of optimal non-reciprocal devices. PMID:27048760

  18. X-Ray-Induced Damage to the Submandibular Salivary Glands in Mice: An Analysis of Strain-Specific Responses

    PubMed Central

    Kamiya, Mana; Kawase, Tomoyuki; Hayama, Kazuhide; Tsuchimochi, Makoto; Okuda, Kazuhiro; Yoshie, Hiromasa

    2015-01-01

    Abstract Radiation therapy for head and neck cancers often causes xerostomia (dry mouth) by acutely damaging the salivary glands through the induction of severe acute inflammation. By contrast, the mechanism underlying the X-ray-induced delayed salivary dysfunction is unknown and has attracted increasing attention. To identify and develop a mouse model that distinguishes the delayed from the acute effects, we examined three different mouse strains (C57BL/6, ICR, and ICR-nu/nu) that showed distinct T-cell activities to comparatively analyze their responses to X-ray irradiation. Three strains were irradiated with X-rays (25 Gy), and functional changes of the submandibular glands were examined by determining pilocarpine-induced saliva secretion. Structural changes were evaluated using histopathological and immunohistochemical examinations of CD3, cleaved poly (ADP-ribose) polymerase (PARP), and Bcl-xL. In C57BL/6 mice, the X-ray irradiation induced acute inflammation accompanied by severe inflammatory cell infiltration at 4 days postirradiation, causing substantial destruction and significant dysfunction at 2 weeks. Fibrotic repair was observed at 16 weeks. In ICR-nu/nu mice, the inflammation and organ destruction were much milder than in the other mice strains, but increased apoptotic cells and a significant reduction in salivary secretion were observed at 4 and 8 weeks and beyond, respectively. These results suggest that in C57BL/6 mice, X-ray-induced functional and structural damage to the salivary glands is caused mainly by acute inflammation. By contrast, although neither acute inflammation nor organ destruction was observed in ICR-nu/nu mice, apoptotic cell death preceded the dysfunction in salivary secretion in the later phase. These data suggest that the X-ray-irradiated ICR-nu/nu mouse may be a useful animal model for developing more specific therapeutic methods for the delayed dysfunction of salivary glands. PMID:26309806

  19. X-ray Inducible Luminescence and Singlet Oxygen Sensitization by an Octahedral Molybdenum Cluster Compound: A New Class of Nanoscintillators.

    PubMed

    Kirakci, Kaplan; Kubát, Pavel; Fejfarová, Karla; Martinčík, Jiří; Nikl, Martin; Lang, Kamil

    2016-01-19

    Newly synthesized octahedral molybdenum cluster compound (n-Bu4N)2[Mo6I8(OOC-1-adamantane)6] revealed uncharted features applicable for the development of X-ray inducible luminescent materials and sensitizers of singlet oxygen, O2((1)Δg). The compound exhibits a red-NIR luminescence in the solid state and in solution (e.g., quantum yield of 0.76 in tetrahydrofuran) upon excitation by UV-vis light. The luminescence originating from the excited triplet states is quenched by molecular oxygen to produce O2((1)Δg) with a high quantum yield. Irradiation of the compound by X-rays generated a radioluminescence with the same emission spectrum as that obtained by UV-vis excitation. It proves the formation of the same excited triplet states regardless of the excitation source. By virtue of the described behavior, the compound is suggested as an efficient sensitizer of O2((1)Δg) upon X-ray excitation. The luminescence and radioluminescence properties were maintained upon embedding the compound in polystyrene films. In addition, polystyrene induced an enhancement of the radioluminescence intensity via energy transfer from the scintillating polymeric matrix. Sulfonated polystyrene nanofibers were used for the preparation of nanoparticles which form stable dispersions in water, while keeping intact the luminescence properties of the embedded compound over a long time period. Due to their small size and high oxygen diffusivity, these nanoparticles are suitable carriers of sensitizers of O2((1)Δg). The presented results define a new class of nanoscintillators with promising properties for X-ray inducible photodynamic therapy.

  20. X-Ray-Induced Damage to the Submandibular Salivary Glands in Mice: An Analysis of Strain-Specific Responses.

    PubMed

    Kamiya, Mana; Kawase, Tomoyuki; Hayama, Kazuhide; Tsuchimochi, Makoto; Okuda, Kazuhiro; Yoshie, Hiromasa

    2015-01-01

    Radiation therapy for head and neck cancers often causes xerostomia (dry mouth) by acutely damaging the salivary glands through the induction of severe acute inflammation. By contrast, the mechanism underlying the X-ray-induced delayed salivary dysfunction is unknown and has attracted increasing attention. To identify and develop a mouse model that distinguishes the delayed from the acute effects, we examined three different mouse strains (C57BL/6, ICR, and ICR-nu/nu) that showed distinct T-cell activities to comparatively analyze their responses to X-ray irradiation. Three strains were irradiated with X-rays (25 Gy), and functional changes of the submandibular glands were examined by determining pilocarpine-induced saliva secretion. Structural changes were evaluated using histopathological and immunohistochemical examinations of CD3, cleaved poly (ADP-ribose) polymerase (PARP), and Bcl-xL. In C57BL/6 mice, the X-ray irradiation induced acute inflammation accompanied by severe inflammatory cell infiltration at 4 days postirradiation, causing substantial destruction and significant dysfunction at 2 weeks. Fibrotic repair was observed at 16 weeks. In ICR-nu/nu mice, the inflammation and organ destruction were much milder than in the other mice strains, but increased apoptotic cells and a significant reduction in salivary secretion were observed at 4 and 8 weeks and beyond, respectively. These results suggest that in C57BL/6 mice, X-ray-induced functional and structural damage to the salivary glands is caused mainly by acute inflammation. By contrast, although neither acute inflammation nor organ destruction was observed in ICR-nu/nu mice, apoptotic cell death preceded the dysfunction in salivary secretion in the later phase. These data suggest that the X-ray-irradiated ICR-nu/nu mouse may be a useful animal model for developing more specific therapeutic methods for the delayed dysfunction of salivary glands. PMID:26309806

  1. Reciprocal Paracrine Interactions Between Normal Human Epithelial and Mesenchymal Cells Protect Cellular DNA from Radiation-Induced Damage

    SciTech Connect

    Nakazawa, Yuka; Saenko, Vladimir Rogounovitch, Tatiana; Suzuki, Keiji; Mitsutake, Norisato; Matsuse, Michiko; Yamashita, Shunichi

    2008-06-01

    Purpose: To explore whether interactions between normal epithelial and mesenchymal cells can modulate the extent of radiation-induced DNA damage in one or both types of cells. Methods and Materials: Human primary thyrocytes (PT), diploid fibroblasts BJ, MRC-5, and WI-38, normal human mammary epithelial cells (HMEC), and endothelial human umbilical cord vein endothelial cells (HUV-EC-C), cultured either individually or in co-cultures or after conditioned medium transfer, were irradiated with 0.25 to 5 Gy of {gamma}-rays and assayed for the extent of DNA damage. Results: The number of {gamma}-H2AX foci in co-cultures of PT and BJ fibroblasts was approximately 25% lower than in individual cultures at 1 Gy in both types of cells. Reciprocal conditioned medium transfer to individual cultures before irradiation resulted in approximately a 35% reduction of the number {gamma}-H2AX foci at 1 Gy in both types of cells, demonstrating the role of paracrine soluble factors. The DNA-protected state of cells was achieved within 15 min after conditioned medium transfer; it was reproducible and reciprocal in several lines of epithelial cells and fibroblasts, fibroblasts, and endothelial cells but not in epithelial and endothelial cells. Unlike normal cells, human epithelial cancer cells failed to establish DNA-protected states in fibroblasts and vice versa. Conclusions: The results imply the existence of a network of reciprocal interactions between normal epithelial and some types of mesenchymal cells mediated by soluble factors that act in a paracrine manner to protect DNA from genotoxic stress.

  2. Reciprocity and gyrotropism in magnetic resonance transduction

    SciTech Connect

    Tropp, James

    2006-12-15

    We give formulas for transduction in magnetic resonance - i.e., the appearance of an emf due to Larmor precession of spins - based upon the modified Lorentz reciprocity principle for gyrotropic (also called 'nonreciprocal') media, i.e., in which a susceptibility tensor is carried to its transpose by reversal of an external static field [cf., R. F. Harrington and A. T. Villeneuve IRE Trans. Microwave Theory and Technique MTT6, 308 (1958)]. Prior applications of reciprocity to magnetic resonance, despite much success, have ignored the gyrotropism which necessarily arises due to nuclear and/or unpaired electronic spins. For detection with linearly polarized fields, oscillating at the Larmor frequency, the emf is written in terms of a volume integral containing a product of two factors which we define as the antenna patterns, i.e. (H{sub 1x}{+-}iH{sub 1y}), where, e.g., for a single transceive antenna, the H's are just the spatially dependent oscillatory magnetic field strengths, per the application of some reference current at the antenna terminals, with the negative sign obtaining for transmission, and the positive for reception. Similar expressions hold for separate transmit and receive antennas; expressions are also given for circular polarization of the fields. We then exhibit a receive-only array antenna of two elements for magnetic resonance imaging of protons, which, due an intensity artifact arising from stray reactive coupling of the elements, produces, despite its own bilateral symmetry, asymmetric proton NMR images of a symmetric cylindrical phantom containing aqueous saline solution [J. Tropp and T. Schirmer, J. Magn. Reson. 151, 146 (2001)]. Modification of this two-port antenna, to function in transmit-receive mode, allows us to demonstrate highly nonreciprocal behavior: that is, to record images (of cylindrical test phantoms containing aqueous saline solution) whose appearance dramatically changes, when the roles of transmission and reception are

  3. [Organ trade versus reciprocity model. An ethical evaluation].

    PubMed

    Illies, C; Weber, F

    2004-02-01

    We perform an ethical evaluation of two models that promise to solve the increasing shortage of organs for transplantations: firstly, the legalization of organ trade, and, secondly, the so called "Reciprocity Model". Thereby unrestricted respect for the individual human being serves as the ethical standard. We conclude that the Reciprocity Model is ethically much more acceptable that organ trade even if this trade were limited to Europe. In addition, the Reciprocity Model can easily be integrated into the current Eurotransplant system of organ allocation. PMID:14750056

  4. What controls network reciprocity in the Prisoner's Dilemma game?

    PubMed

    Yamauchi, Atsuo; Tanimoto, Jun; Hagishima, Aya

    2010-01-01

    The evolutionary Prisoner's Dilemma game in structured networks has been studied extensively to understand network reciprocity. However, in some cases results of these studies cannot be compared because not only the network structures but also the network parameters, rules for updating strategies, and update dynamics differ among them. In this study, we investigated the effect of experimental conditions by conducting a series of systematic factorial experiments. We found that those experimental assumptions are significantly important in network reciprocity, although we confirmed that network reciprocity can be basically explained by the average degree of the network (Nowak, 2006; Ohtsuki et al., 2006).

  5. Focal plane scanner with reciprocating spatial window

    NASA Technical Reports Server (NTRS)

    Mao, Chengye (Inventor)

    2000-01-01

    A focal plane scanner having a front objective lens, a spatial window for selectively passing a portion of the image therethrough, and a CCD array for receiving the passed portion of the image. All embodiments have a common feature whereby the spatial window and CCD array are mounted for simultaneous relative reciprocating movement with respect to the front objective lens, and the spatial window is mounted within the focal plane of the front objective. In a first embodiment, the spatial window is a slit and the CCD array is one-dimensional, and successive rows of the image in the focal plane of the front objective lens are passed to the CCD array by an image relay lens interposed between the slit and the CCD array. In a second embodiment, the spatial window is a slit, the CCD array is two-dimensional, and a prism-grating-prism optical spectrometer is interposed between the slit and the CCD array so as to cause the scanned row to be split into a plurality of spectral separations onto the CCD array. In a third embodiment, the CCD array is two-dimensional and the spatial window is a rectangular linear variable filter (LVF) window, so as to cause the scanned rows impinging on the LVF to be bandpass filtered into spectral components onto the CCD array through an image relay lens interposed between the LVF and the CCD array.

  6. Non-reciprocal Brillouin scattering induced transparency

    NASA Astrophysics Data System (ADS)

    Kim, Junhwan; Kuzyk, Mark C.; Han, Kewen; Wang, Hailin; Bahl, Gaurav

    2015-03-01

    Electromagnetically induced transparency provides a powerful mechanism for controlling light propagation in a dielectric medium, and for producing slow and fast light. Electromagnetically induced transparency traditionally arises from destructive interference induced by a non-radiative coherence in an atomic system. Stimulated Brillouin scattering of light from propagating hypersonic acoustic waves has also been used successfully for the generation of slow and fast light. However, Electromagnetically induced transparency-type processes based on stimulated Brillouin scattering were considered infeasible because of the short coherence lifetime of hypersonic phonons. Here, we report a new Brillouin scattering induced transparency phenomenon generated by acousto-optic interaction of light with long-lived propagating phonons in a silica resonator. We demonstrate that Brillouin scattering induced transparency is uniquely non-reciprocal owing to the propagating acoustic wave and accompanying momentum conservation requirement. We also show that Brillouin scattering induced transparency enables ultralow-power ultralow-footprint slow-light generation with delay-bandwidth product comparable to state-of-the-art stimulated Brillouin scattering systems.

  7. Stochastic evolutionary dynamics of direct reciprocity.

    PubMed

    Imhof, Lorens A; Nowak, Martin A

    2010-02-01

    Evolutionary game theory is the study of frequency-dependent selection. The success of an individual depends on the frequencies of strategies that are used in the population. We propose a new model for studying evolutionary dynamics in games with a continuous strategy space. The population size is finite. All members of the population use the same strategy. A mutant strategy is chosen from some distribution over the strategy space. The fixation probability of the mutant strategy in the resident population is calculated. The new mutant takes over the population with this probability. In this case, the mutant becomes the new resident. Otherwise, the existing resident remains. Then, another mutant is generated. These dynamics lead to a stationary distribution over the entire strategy space. Our new approach generalizes classical adaptive dynamics in three ways: (i) the population size is finite; (ii) mutants can be drawn non-locally and (iii) the dynamics are stochastic. We explore reactive strategies in the repeated Prisoner's Dilemma. We perform 'knock-out experiments' to study how various strategies affect the evolution of cooperation. We find that 'tit-for-tat' is a weak catalyst for the emergence of cooperation, while 'always cooperate' is a strong catalyst for the emergence of defection. Our analysis leads to a new understanding of the optimal level of forgiveness that is needed for the evolution of cooperation under direct reciprocity.

  8. Experimental Assessment of the Reciprocating Feed System

    NASA Technical Reports Server (NTRS)

    Eddleman, David E.; Blackmon, James B.; Morton, Christopher D.

    2006-01-01

    The primary goal of this project was to design, construct, and test a full scale, high pressure simulated propellant feed system test bed that could evaluate the ability of the Reciprocating Feed System (RFS) to provide essentially constant flow rates and pressures to a rocket engine. The two key issues addressed were the effects of the transition of the drain cycle from tank to tank and the benefits of other hardware such as accumulators to provide a constant pressure flow rate out of the RFS. The test bed provided 500 psi flow at rates of the order of those required for engines in the 20,000 lbf thrust class (e.g., 20 to 40 lb/sec). A control system was developed in conjunction with the test article and automated system operation was achieved. Pre-test planning and acceptance activities such as a documented procedure and hazard analysis were conducted and the operation of the test article was approved by, and conducted in coordination with, appropriate NASA Marshall Space Flight Center personnel under a Space Act Agreement. Tests demonstrated successful control of flow rates and pressures.

  9. Stereotactic radiosurgery - Gamma Knife

    MedlinePlus

    ... Gamma Knife; Gamma Knife radiosurgery; Non-invasive neurosugery; Epilepsy - Gamma Knife ... problems ( arteriovenous malformation , arteriovenous fistula ) Some types of epilepsy Trigeminal neuralgia (severe nerve pain of the face) ...

  10. Indirect reciprocity and the evolution of "moral signals"

    PubMed

    Smead, Rory

    2010-01-01

    Signals regarding the behavior of others are an essential element of human moral systems and there are important evolutionary connections between language and large-scale cooperation. In particular, social communication may be required for the reputation tracking needed to stabilize indirect reciprocity. Additionally, scholars have suggested that the benefits of indirect reciprocity may have been important for the evolution of language and that social signals may have coevolved with large-scale cooperation. This paper investigates the possibility of such a coevolution. Using the tools of evolutionary game theory, we present a model that incorporates primitive "moral signaling" into a simple setting of indirect reciprocity. This model reveals some potential difficulties for the evolution of "moral signals." We find that it is possible for "moral signals" to evolve alongside indirect reciprocity, but without some external pressure aiding the evolution of a signaling system, such a coevolution is unlikely.

  11. Mature care and reciprocity: two cases from acute psychiatry.

    PubMed

    Pettersen, Tove; Hem, Marit Helene

    2011-03-01

    In this article we elaborate on the concept of mature care, in which reciprocity is crucial. Emphasizing reciprocity challenges other comprehensions where care is understood as a one-sided activity, with either the carer or the cared for considered the main source of knowledge and sole motivation for caring. We aim to demonstrate the concept of mature care's advantages with regard to conceptualizing the practice of care, such as in nursing. First, we present and discuss the concept of mature care, then we apply the concept to two real life cases taken from the field of acute psychiatry. In the first example we demonstrate how mature care can grasp tacit reciprocal aspects in caring. In the other, we elucidate a difficulty related to the concept, namely the lack of reciprocity and interaction that affects some relationships.

  12. Drift stabilizer for reciprocating free-piston devices

    DOEpatents

    Ward, William C.; Corey, John A.; Swift, Gregory W.

    2003-05-20

    A free-piston device has a stabilized piston drift. A piston having a frequency of reciprocation over a stroke length and with first and second sides facing first and second variable volumes, respectively, for containing a working fluid defining an acoustic wavelength at the frequency of reciprocation. A bypass tube waveguide connects the first and second variable volumes at all times during reciprocation of the piston. The waveguide has a relatively low impedance for steady flow and a relatively high impedance for oscillating flow at the frequency of reciprocation of the piston, so that steady flow returns fluid leakage from about the piston between the first and second volumes while oscillating flow is not diverted through the waveguide. Thus, net leakage about the piston is returned during each stroke of the piston while oscillating leakage is not allowed and pressure buildup on either the first or second side of the piston is avoided to provide a stable piston location.

  13. Reciprocal Rights and Responsibilities in Parent-Child Relations

    ERIC Educational Resources Information Center

    Baumrind, Diana

    1978-01-01

    This article examines critically the case for protecting children's rights as against the case for protecting children's welfare. The principle of reciprocity in parent-child relations is rejected. (Author/AM)

  14. Research on networked manufacturing system for reciprocating pump industry

    NASA Astrophysics Data System (ADS)

    Wu, Yangdong; Qi, Guoning; Xie, Qingsheng; Lu, Yujun

    2005-12-01

    Networked manufacturing is a trend of reciprocating pump industry. According to the enterprises' requirement, the architecture of networked manufacturing system for reciprocating pump industry was proposed, which composed of infrastructure layer, system management layer, application service layer and user layer. Its main functions included product data management, ASP service, business management, and customer relationship management, its physics framework was a multi-tier internet-based model; the concept of ASP service integration was put forward and its process model was also established. As a result, a networked manufacturing system aimed at the characteristics of reciprocating pump industry was built. By implementing this system, reciprocating pump industry can obtain a new way to fully utilize their own resources and enhance the capabilities to respond to the global market quickly.

  15. 19. View northwest of Tropic Chamber reciprocal compressors (typical), in ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    19. View northwest of Tropic Chamber reciprocal compressors (typical), in machine area. - Natick Research & Development Laboratories, Climatic Chambers Building, U.S. Army Natick Research, Development & Engineering Center (NRDEC), Natick, Middlesex County, MA

  16. Network reciprocity by coexisting learning and teaching strategies

    NASA Astrophysics Data System (ADS)

    Tanimoto, Jun; Brede, Markus; Yamauchi, Atsuo

    2012-03-01

    We propose a network reciprocity model in which an agent probabilistically adopts learning or teaching strategies. In the learning adaptation mechanism, an agent may copy a neighbor's strategy through Fermi pairwise comparison. The teaching adaptation mechanism involves an agent imposing its strategy on a neighbor. Our simulations reveal that the reciprocity is significantly affected by the frequency with which learning and teaching agents coexist in a network and by the structure of the network itself.

  17. The role of the arachidonic acid cascade in the species-specific X-ray-induced inflammation of the rabbit eye

    SciTech Connect

    Bito, L.Z.; Klein, E.M.

    1982-05-01

    To identify the mediator(s) of the apparently species-specific X-ray-induced inflammation of the rabbit eye, inhibitors of the synthesis and/or release of known or putative mediators of ocular inflammation were administered prior to irradiation. The X-ray-induced ocular inflammation, particularly the rise in intraocular pressure, was found to be inhibited by intravenous pretreatment of rabbits with flurbiprofen, indomethacin, or imidazole (1, 10, and 100 mg/kg i.v., respectively), or by combined intravitreal and topical administration of flurbiprofen. Systemic, intravitreal, and/or topical pretreatment with prednisolone or disodium cromoglycate or the retrobulbar injection of ethyl alcohol or capsaicin failed to block the inflammatory response, whereas vitamin E apparently exerted some protective effect. These findings show that the X-ray-induced inflammation of the rabbit eye is mediated, at least in part, by prostaglandins (PGs) and/or related autacoids. In addition, these results suggest that the unique sensitivity of the rabbit eye to X-ray-induced inflammation is due either to the presence in this species of a unique or uniquely effective triggering mechanism for the release of PG precursors or to the greater sensitivity of this species to the ocular inflammatory effects of PGs. Thus the rabbit eye may provide a unique model for studying some aspects of arachidonic acid release or ocular PG effects, but extreme caution must be exercised in generalizing such findings to other species.

  18. Strong reciprocity, human cooperation, and the enforcement of social norms.

    PubMed

    Fehr, Ernst; Fischbacher, Urs; Gächter, Simon

    2002-03-01

    This paper provides strong evidence challenging the self-interest assumption that dominates the behavioral sciences and much evolutionary thinking. The evidence indicates that many people have a tendency to voluntarily cooperate, if treated fairly, and to punish noncooperators. We call this behavioral propensity "strong reciprocity" and show empirically that it can lead to almost universal cooperation in circumstances in which purely self-interested behavior would cause a complete breakdown of cooperation. In addition, we show that people are willing to punish those who behaved unfairly towards a third person or who defected in a Prisoner's Dilemma game with a third person. This suggests that strong reciprocity is a powerful device for the enforcement of social norms involving, for example, food sharing or collective action. Strong reciprocity cannot be rationalized as an adaptive trait by the leading evolutionary theories of human cooperation (in other words, kin selection, reciprocal altruism, indirect reciprocity, and costly signaling theory). However, multilevel selection theories of cultural evolution are consistent with strong reciprocity.

  19. Indirect reciprocity in three types of social dilemmas.

    PubMed

    Nakamura, Mitsuhiro; Ohtsuki, Hisashi

    2014-08-21

    Indirect reciprocity is a key mechanism for the evolution of human cooperation. Previous studies explored indirect reciprocity in the so-called donation game, a special class of Prisoner's Dilemma (PD) with unilateral decision making. A more general class of social dilemmas includes Snowdrift (SG), Stag Hunt (SH), and PD games, where two players perform actions simultaneously. In these simultaneous-move games, moral assessments need to be more complex; for example, how should we evaluate defection against an ill-reputed, but now cooperative, player? We examined indirect reciprocity in the three social dilemmas and identified twelve successful social norms for moral assessments. These successful norms have different principles in different dilemmas for suppressing cheaters. To suppress defectors, any defection against good players is prohibited in SG and PD, whereas defection against good players may be allowed in SH. To suppress unconditional cooperators, who help anyone and thereby indirectly contribute to jeopardizing indirect reciprocity, we found two mechanisms: indiscrimination between actions toward bad players (feasible in SG and PD) or punishment for cooperation with bad players (effective in any social dilemma). Moreover, we discovered that social norms that unfairly favor reciprocators enhance robustness of cooperation in SH, whereby reciprocators never lose their good reputation.

  20. Asymmetric reproductive isolation during simultaneous reciprocal mating in pulmonates

    PubMed Central

    Wiwegweaw, Amporn; Seki, Keiichi; Mori, Hiroshi; Asami, Takahiro

    2009-01-01

    The generality of asymmetric reproductive isolation between reciprocal crosses suggests that the evolution of isolation mechanisms often proceeds in reciprocal asymmetry. In hermaphroditic snails that copulate simultaneously and reciprocally, asymmetry in premating isolation may not be readily detectable because the failure of the symmetric performance of courtship would prevent copulation from occurring. On the other hand, through their prolonged copulation, snails discriminate among mates when exchanging spermatophores for their benefit and thus may exhibit asymmetric reproductive isolation during interspecific mating. However, no clear case of reciprocal asymmetry has been found in reproductive isolation between snail species. Here we show a discrete difference in hybridization success between simultaneous reciprocal copulations between two species of pulmonate snails. Premating isolation of Bradybaena pellucida (BP) and Bradybaena similaris (BS) is incomplete in captivity. In interspecific copulation, BP removes its penis without transferring a spermatophore, while BS sires hybrids by inseminating BP. Thus, ‘male’ BP or ‘female’ BS rejects the other individual, while female BP and male BS accept each other, so that the two sexes of either BP or BS oppose each other in mate discrimination. Our results are a clear example of asymmetry in reproductive isolation during simultaneous reciprocal mating between hermaphroditic animals. PMID:19141413

  1. Reciprocity on Demand : Sharing and Exchanging Food in Northwestern Namibia.

    PubMed

    Schnegg, Michael

    2015-09-01

    Two competing models concerning food transfers prominent in the anthropological literature conceptualize such transfers either as sharing or as exchange. Sharing is understood as situational transactions formed through demands and unconditional giving, whereas reciprocal exchange is understood in terms of networking and keeping score. I propose that the picture is more complicated than these classifications suggests. Drawing on data collected in Northwestern Namibia, I show that sharing and reciprocal exchange are dynamically interrelated in actual food transfers. As a local norm, people can demand food from anyone, and they are typically given food in response to a demand. However, in practice, food transfer networks emerge (N = 62) that are highly reciprocal and fit the exchange model much better. Although the sharing norm makes no restrictions on whom to ask, in practice people often turn to their neighbors. Interpersonal dynamics account for why some of those ties become strongly reciprocal and others do not. Under these circumstances, unconditional sharing, a norm that has been viewed as an alternative to exchange, can lead to reciprocity via reciprocity on demand.

  2. Bah humbug: Unexpected Christmas cards and the reciprocity norm.

    PubMed

    Meier, Brian P

    2016-01-01

    The reciprocity norm refers to the expectation that people will help those who helped them. A well-known study revealed that the norm is strong with Christmas cards, with 20% of people reciprocating a Christmas card received from a stranger. I attempted to conceptually replicate and extend this effect. In Study 1, 755 participants received a Christmas card supposedly from a more- versus less-similar stranger. The reciprocation rate was unexpectedly low (2%), which did not allow for a test of a similarity effect. Two potential reasons for this low rate were examined in Study 2 in which 494 participants reported their likelihood of reciprocating a Christmas card from a stranger as well as their felt suspicions/threat about the card and their frequency of e-mail use. Reciprocation likelihood was negatively correlated with perceived threat/suspicion and e-mail use. It appears that reciprocating a gift from a stranger in offline settings may be less likely than expected. PMID:26666577

  3. Reciprocity in the electronic stopping of slow ions in matter

    NASA Astrophysics Data System (ADS)

    Sigmund, P.

    2008-04-01

    The principle of reciprocity, i.e., the invariance of the inelastic excitation in ion-atom collisions against interchange of projectile and target, has been applied to the electronic stopping cross section of low-velocity ions and tested empirically on ion-target combinations supported by a more or less adequate amount of experimental data. Reciprocity is well obeyed (within ~10%) for many systems studied, and deviations exceeding ~20% are exceptional. Systematic deviations such as gas-solid or metal-insulator differences have been looked for but not identified on the present basis. A direct consequence of reciprocity is the equivalence of Z1 with Z2 structure for random slowing down. This feature is reasonably well supported empirically for ion-target combinations involving carbon, nitrogen, aluminium and argon. Reciprocity may be utilized as a criterion to reject questionable experimental data. In cases where a certain stopping cross section has not been or cannot be measured, the stopping cross section for the inverted system may be available and serve as a first estimate. It is suggested to build in reciprocity as a fundamental requirement into empirical interpolation schemes directed at the stopping of low-velocity ions. Examination of the SRIM and MSTAR codes reveals cases where reciprocity is obeyed accurately, but deviations of up to a factor of two are common. In case of heavy ions such as gold, electronic stopping cross sections predicted by SRIM are asserted to be almost an order of magnitude too high.

  4. Preschool children's behavioral tendency toward social indirect reciprocity.

    PubMed

    Kato-Shimizu, Mayuko; Onishi, Kenji; Kanazawa, Tadahiro; Hinobayashi, Toshihiko

    2013-01-01

    Social indirect reciprocity seems to be crucial in enabling large-scale cooperative networks among genetically unrelated individuals in humans. However, there are relatively few studies on social indirect reciprocity in children compared to adults. Investigating whether young children have a behavioral tendency toward social indirect reciprocity will help us understand how and when the fundamental ability to form cooperative relationships among adults is acquired. Using naturalistic observation at a nursery school, this study examined whether 5- to 6-year-olds show a behavioral tendency to engage in social indirect reciprocity in response to their peers' prosocial behavior toward a third party. The results revealed that bystander children tended to display prosocial behavior toward their peers more frequently after observing these peers' prosocial behavior toward third-party peers, compared with control situations; this suggests that 5- to 6-year-olds may have an essential behavioral tendency to establish social indirect reciprocity when interacting with peers in their daily lives. In addition, bystanders tended to display affiliative behavior after observing focal children's prosocial behavior. In other words, observing peers' prosocial behavior toward third-party peers evoked bystanders' positive emotions toward the helpers. Considering both the present results and previous findings, we speculate that in preschoolers, such positive emotions might mediate the increase in the bystander's prosocial behavior toward the helper. In addition, an intuitional emotional process plays an important role in the preschooler's behavioral tendency toward social indirect reciprocity in natural interactions with peers.

  5. Bah humbug: Unexpected Christmas cards and the reciprocity norm.

    PubMed

    Meier, Brian P

    2016-01-01

    The reciprocity norm refers to the expectation that people will help those who helped them. A well-known study revealed that the norm is strong with Christmas cards, with 20% of people reciprocating a Christmas card received from a stranger. I attempted to conceptually replicate and extend this effect. In Study 1, 755 participants received a Christmas card supposedly from a more- versus less-similar stranger. The reciprocation rate was unexpectedly low (2%), which did not allow for a test of a similarity effect. Two potential reasons for this low rate were examined in Study 2 in which 494 participants reported their likelihood of reciprocating a Christmas card from a stranger as well as their felt suspicions/threat about the card and their frequency of e-mail use. Reciprocation likelihood was negatively correlated with perceived threat/suspicion and e-mail use. It appears that reciprocating a gift from a stranger in offline settings may be less likely than expected.

  6. Induction of reciprocal translocations in rhesus monkey stem-cell spermatogonia: effects of low doses and low dose rates

    SciTech Connect

    van Buul, P.P.; Richardson, J.F. Jr.; Goudzwaard, J.H.

    1986-01-01

    The induction of reciprocal translocation in rhesus monkey spermatogonial stem cells was studied following exposure to low doses of acute X rays (0.25 Gy, 300 mGy/min) or to low-dose-rate X rays (1 Gy, 2 mGy/min) and gamma rays (1 Gy, 0.2 mGy/min). The results obtained at 0.25 Gy of X rays fitted exactly the linear extrapolation down from the 0.5 and 1.0 Gy points obtained earlier. Extension of X-ray exposure reduced the yield of translocations similar to that in the mouse by about 50%. The reduction to 40% of translocation rate after chronic gamma exposure was clearly less than the value of about 80% reported for the mouse over the same range of dose rates. Differential cell killing with ensuing differential elimination of aberration-carrying cells is the most likely explanation for the differences between mouse and monkey.

  7. Reciprocal regulation of transcription factors and PLC isozyme gene expression in adult cardiomyocytes.

    PubMed

    Singal, Tushi; Dhalla, Naranjan S; Tappia, Paramjit S

    2010-06-01

    By employing a pharmacological approach, we have shown that phospholipase C (PLC) activity is involved in the regulation of gene expression of transcription factors such as c-Fos and c-Jun in cardiomyocytes in response to norepinephrine (NE). However, there is no information available regarding the identity of specific PLC isozymes involved in the regulation of c-Fos and c-Jun or on the involvement of these transcription factors in PLC isozyme gene expression in adult cardiomyocytes. In this study, transfection of cardiomyocytes with PLC isozyme specific siRNA was found to prevent the NE-mediated increases in the corresponding PLC isozyme gene expression, protein content and activity. Unlike PLC gamma(1) gene, silencing of PLC beta(1), beta(3) and delta(1) genes with si RNA prevented the increases in c-Fos and c-Jun gene expression in response to NE. On the other hand, transfection with c-Jun si RNA suppressed the NE-induced increase in c-Jun as well as PLC beta(1), beta(3) and delta(1) gene expression, but had no effect on PLC gamma(1) gene expression. Although transfection of cardiomyocytes with c-Fos si RNA prevented NE-induced expression of c-Fos, PLC beta(1) and PLC beta(3) genes, it did not affect the increases in PLC delta(1) and PLC gamma(1) gene expression. Silencing of either c-Fos or c-Jun also depressed the NE-mediated increases in PLC beta(1), beta(3) and gamma(1) protein content and activity in an isozyme specific manner. Furthermore, silencing of all PLC isozymes as well as of c-Fos and c-Jun resulted in prevention of the NE-mediated increase in atrial natriuretic factor gene expression. These findings, by employing gene silencing techniques, demonstrate that there occurs a reciprocal regulation of transcription factors and specific PLC isozyme gene expression in cardiomyocytes.

  8. Analytical Assessment of the Reciprocating Feed System

    NASA Technical Reports Server (NTRS)

    Eddleman, David E.; Blackmon, James B.; Morton, Christopher D.

    2006-01-01

    A preliminary analysis tool has been created in Microsoft Excel to determine deliverable payload mass, total system mass, and performance of spacecraft systems using various types of propellant feed systems. These mass estimates are conducted by inserting into the user interface the basic mission parameters (e.g., thrust, burn time, specific impulse, mixture ratio, etc.), system architecture (e.g., propulsion system type and characteristics, propellants, pressurization system type, etc.), and design properties (e.g., material properties, safety factors, etc.). Different propellant feed and pressurization systems are available for comparison in the program. This gives the user the ability to compare conventional pressure fed, reciprocating feed system (RFS), autogenous pressurization thrust augmentation (APTA RFS), and turbopump systems with the deliverable payload, inert mass, and total system mass being the primary comparison metrics. Analyses of several types of missions and spacecraft were conducted and it was found that the RFS offers a performance improvement, especially in terms of delivered payload, over conventional pressure fed systems. Furthermore, it is competitive with a turbopump system at low to moderate chamber pressures, up to approximately 1,500 psi. Various example cases estimating the system mass and deliverable payload of several types of spacecraft are presented that illustrate the potential system performance advantages of the RFS. In addition, a reliability assessment of the RFS was conducted, comparing it to simplified conventional pressure fed and turbopump systems, based on MIL-STD 756B; these results showed that the RFS offers higher reliability, and thus substantially longer periods between system refurbishment, than turbopump systems, and is competitive with conventional pressure fed systems. This is primarily the result of the intrinsic RFS fail-operational capability with three run tanks, since the system can operate with just two run

  9. Reciprocating flow-based centrifugal microfluidics mixer.

    PubMed

    Noroozi, Zahra; Kido, Horacio; Micic, Miodrag; Pan, Hansheng; Bartolome, Christian; Princevac, Marko; Zoval, Jim; Madou, Marc

    2009-07-01

    Proper mixing of reagents is of paramount importance for an efficient chemical reaction. While on a large scale there are many good solutions for quantitative mixing of reagents, as of today, efficient and inexpensive fluid mixing in the nanoliter and microliter volume range is still a challenge. Complete, i.e., quantitative mixing is of special importance in any small-scale analytical application because the scarcity of analytes and the low volume of the reagents demand efficient utilization of all available reaction components. In this paper we demonstrate the design and fabrication of a novel centrifugal force-based unit for fast mixing of fluids in the nanoliter to microliter volume range. The device consists of a number of chambers (including two loading chambers, one pressure chamber, and one mixing chamber) that are connected through a network of microchannels, and is made by bonding a slab of polydimethylsiloxane (PDMS) to a glass slide. The PDMS slab was cast using a SU-8 master mold fabricated by a two-level photolithography process. This microfluidic mixer exploits centrifugal force and pneumatic pressure to reciprocate the flow of fluid samples in order to minimize the amount of sample and the time of mixing. The process of mixing was monitored by utilizing the planar laser induced fluorescence (PLIF) technique. A time series of high resolution images of the mixing chamber were analyzed for the spatial distribution of light intensities as the two fluids (suspension of red fluorescent particles and water) mixed. Histograms of the fluorescent emissions within the mixing chamber during different stages of the mixing process were created to quantify the level of mixing of the mixing fluids. The results suggest that quantitative mixing was achieved in less than 3 min. This device can be employed as a stand alone mixing unit or may be integrated into a disk-based microfluidic system where, in addition to mixing, several other sample preparation steps may be

  10. Atrioventricular reciprocal rhythm and chronic reciprocating tachycardia in a newborn infant with concealed Wolff-Parkinson-White syndrome.

    PubMed Central

    Sung, R J; Ferrer, P; Garcia, O L; Castellanos, A; Gelband, H

    1977-01-01

    A case of atrioventricular reciprocal rhythm and chronic reciprocating tachycardia in a newborn infant is presented. Electrophysiological studies suggest that these rhythm disturbances are related to the presence of a right-sided atrioventricular accessory pathway capable only of retrograde conduction (concealed Wolff-Parkinson-White syndrome). The technique of recording the sequence of atrial activation during the tachycardia is described and its clinical importance emphasised. PMID:884032

  11. Analysis of the K-ras and p53 pathways in x-ray-induced lung tumors in the rat

    SciTech Connect

    Belinsky, S.A.; Middleton, S.K.; Hahn, F.F.; Nikula, K.J.; Picksley, S.M.

    1996-04-01

    The risk from exposure to low-dose radiation in conjunction with cigarette smoking has not been estimated due in part to lmited knowledge surrounding the molecular mechanisms underlying radiation-induced cancers. The purpose of this investigation was to determine the frequency for alterations in genes within the K-ras and p53 signal and cell cycle regulatory pathways, respectively, in X-ray-induced lung tumors in the F344/N rat. These tumors were examined for genetic alterations in the K-ras, c-raf-1, p53, mdm2 and cip1 genes. No K-ras mutations were detected by sequencing in 18 squamous cell carcinomas (SCCs) or 17 adenocarcinomas. However, using a K-ras codon 12 mutation selection assay, a codon 12 GGT {r_arrow} GAT mutation was detected in one SCC, suggesting that activation of the K-ras proto-oncogene is both a rare and late event. Single-strand conformation polymorphism (SSCP) analysis of the kinase-binding domain of the c-raf-1 gene did not detect any polymorphisms. Three of 18 SCCs but none of the adenocarcinomas showed p53 nuclear immunoreactivity. Single-strand conformation polymorphism analysis of exons 4-9 of the p53 gene detected only an exon 9 mutation in one SCC. Mutations were not detected in the three SCCs with immunoreactive p53 protein. No amplification of the mdm2 gene was detected; however, nuclear mdm2 immunoreactivity was present in one of the three SCCs that stained positive for the p53 protein. The complete cDNA of the rat cip1 gene comprising 810 bases was cloned and sequenced. The frequency of somatic mutations in exon 2 of the cip1 gene was determined by SSCP analysis. No alterations in electrophoretic mobility were detected. The results of this investigation indicate that alterations in the K-ras and p53 pathways do not play a major role in the genesis of X-ray-induced lung tumors in the rat. 49 refs., 5 figs.

  12. Dopant concentration dependent optical and X-Ray induced photoluminescence in Eu3+ doped La2Zr2O7

    NASA Astrophysics Data System (ADS)

    Pokhrel, Madhab; Brik, Mikhail; Mao, Yuanbing

    2015-03-01

    Herein, we will be presenting the dopant (Eu) concentration dependent high density La2Zr2O7 nanoparticles for optical and X-ray scintillation applications by use of X - ray diffraction, Raman, FTIR, scanning electron microscope (SEM), transmission electron microscopy (TEM), optically and X-ray excited photoluminescence (PL). Several theoretical methods have been used in order to investigate the structural, electronic, optical, elastic, dynamic properties of Eu doped La2Zr2O7. It is observed that Eu: La2Zr2O7 shows an intense red luminescence under 258, 322, 394 and 465 nm excitation. The optical intensity of Eu: La2Zr2O7 depends on the dopant concentration of Eu3+. Following high energy excitation with X-rays, Eu: La2Zr2O7 shows an atypical Eu PL response (scintillation) with a red emission. The intense color emission of Eu obtained under 258 nm excitation, the X-ray induced luminescence property along with reportedly high density of La2Zr2O7, makes these nanomaterials attractive for optical and X-ray applications. The authors thank the support from the Defense Threat Reduction Agency (DTRA) of the U.S. Department of Defense (Award #HDTRA1-10-1-0114).

  13. Ultrafast x-ray-induced nuclear dynamics in diatomic molecules using femtosecond x-ray-pump-x-ray-probe spectroscopy

    NASA Astrophysics Data System (ADS)

    Lehmann, C. S.; Picón, A.; Bostedt, C.; Rudenko, A.; Marinelli, A.; Moonshiram, D.; Osipov, T.; Rolles, D.; Berrah, N.; Bomme, C.; Bucher, M.; Doumy, G.; Erk, B.; Ferguson, K. R.; Gorkhover, T.; Ho, P. J.; Kanter, E. P.; Krässig, B.; Krzywinski, J.; Lutman, A. A.; March, A. M.; Ray, D.; Young, L.; Pratt, S. T.; Southworth, S. H.

    2016-07-01

    The capability of generating two intense, femtosecond x-ray pulses with a controlled time delay opens the possibility of performing time-resolved experiments for x-ray-induced phenomena. We have applied this capability to study the photoinduced dynamics in diatomic molecules. In molecules composed of low-Z elements, K -shell ionization creates a core-hole state in which the main decay mode is an Auger process involving two electrons in the valence shell. After Auger decay, the nuclear wave packets of the transient two-valence-hole states continue evolving on the femtosecond time scale, leading either to separated atomic ions or long-lived quasibound states. By using an x-ray pump and an x-ray probe pulse tuned above the K -shell ionization threshold of the nitrogen molecule, we are able to observe ion dissociation in progress by measuring the time-dependent kinetic energy releases of different breakup channels. We simulated the measurements on N2 with a molecular dynamics model that accounts for K -shell ionization, Auger decay, and the time evolution of the nuclear wave packets. In addition to explaining the time-dependent feature in the measured kinetic energy release distributions from the dissociative states, the simulation also reveals the contributions of quasibound states.

  14. In vitro γ-ray-induced inflammatory response is dominated by culturing conditions rather than radiation exposures

    NASA Astrophysics Data System (ADS)

    Babini, G.; Morini, J.; Baiocco, G.; Mariotti, L.; Ottolenghi, A.

    2015-03-01

    The inflammatory pathway has a pivotal role in regulating the fate and functions of cells after a wide range of stimuli, including ionizing radiation. However, the molecular mechanisms governing such responses have not been completely elucidated yet. In particular, the complex activation dynamics of the Nuclear transcription Factor kB (NF-kB), the key molecule governing the inflammatory pathway, still lacks a complete characterization. In this work we focused on the activation dynamics of the NF-kB (subunit p65) pathway following different stimuli. Quantitative measurements of NF-kB were performed and results interpreted within a systems theory approach, based on the negative feedback loop feature of this pathway. Time-series data of nuclear NF-kB concentration showed no evidence of γ-ray induced activation of the pathway for doses up to 5Gy but highlighted important transient effects of common environmental stress (e.g. CO2, temperature) and laboratory procedures, e.g. replacing the culture medium, which dominate the in vitro inflammatory response.

  15. Testing of regolith of celestial bolides with active neutron gamma-ray spectrometry

    NASA Astrophysics Data System (ADS)

    Vostrukhin, Andrey; Mitrofanov, Igor; Golovin, Dmitry; Litvak, Maxim; Sanin, Anton

    2015-04-01

    Current space instruments for studying planet's surface include gamma ray spectrometers that detect natural radioactive isotopes as well as gamma-rays induced in subsurface by galactic cosmic rays. When measuring from celestial body's surface, statistics and amount of detected elements can be dramatically increased with active methods, where soil exposed to artificial flux of particles. One good example is the Russian Dynamic Albedo of Neutron (DAN) instrument onboard Martian Science Laboratory mission (Curiosity rover) developed in 2005-2011. It is the first active neutron spectrometer flown to another planet as part of a landed mission to investigate subsurface water distribution and which has now successfully operated for more than two years on the Martian surface. Presentation describes a number of space instruments for different landers and rovers being developed in Russian Space Research Institute for studying Moon and Mars, as well as method of active neutron and gamma spectrometry overview.

  16. Secondary production of neutral pi-mesons and the diffuse galactic gamma radiation

    NASA Technical Reports Server (NTRS)

    Dermer, C. D.

    1986-01-01

    Isobaric and scaling model predictions of the secondary spectra of neutral pi-mesons produced in proton-proton collisions, at energies between threshold and a few GeV, are compared on the basis of accelerator data and found to show the isobaric model to be superior. This model is accordingly used, in conjuction with a scaling model representation at high energies, in a recalculation of the pi exp (0) gamma-radiation's contribution to the diffuse galactic gamma background; the cosmic ray-induced production of photons (whose energy exceeds 100 MeV) by such radiation occurs at a rate of 1.53 x 10 to the -25 photons/(s-H atom). These results are compared with previous calculations of this process as well as with COS-B observations of the diffuse galactic gamma-radiation.

  17. Gamma ray generator

    SciTech Connect

    Firestone, Richard B; Reijonen, Jani

    2014-05-27

    An embodiment of a gamma ray generator includes a neutron generator and a moderator. The moderator is coupled to the neutron generator. The moderator includes a neutron capture material. In operation, the neutron generator produces neutrons and the neutron capture material captures at least some of the neutrons to produces gamma rays. An application of the gamma ray generator is as a source of gamma rays for calibration of gamma ray detectors.

  18. Two dimensional nanoscale reciprocating sliding contacts of textured surfaces

    NASA Astrophysics Data System (ADS)

    Tong, Ruiting; Liu, Geng; Liu, Tianxiang

    2016-05-01

    Detailed behaviors of nanoscale textured surfaces during the reciprocating sliding contacts are still unknown although they are widely used in mechanical components to improve tribological characteristics. The current research of sliding contacts of textured surfaces mainly focuses on the experimental studies, while the cost is too high. Molecular dynamics(MD) simulation is widely used in the studies of nanoscale single-pass sliding contacts, but the CPU cost of MD simulation is also too high to simulate the reciprocating sliding contacts. In this paper, employing multiscale method which couples molecular dynamics simulation and finite element method, two dimensional nanoscale reciprocating sliding contacts of textured surfaces are investigated. Four textured surfaces with different texture shapes are designed, and a rigid cylindrical tip is used to slide on these textured surfaces. For different textured surfaces, average potential energies and average friction forces of the corresponding sliding processes are analyzed. The analyzing results show that "running-in" stages are different for each texture, and steady friction processes are discovered for textured surfaces II, III and IV. Texture shape and sliding direction play important roles in reciprocating sliding contacts, which influence average friction forces greatly. This research can help to design textured surfaces to improve tribological behaviors in nanoscale reciprocating sliding contacts.

  19. From reciprocity to unconditional altruism through signalling benefits.

    PubMed Central

    Lotem, Arnon; Fishman, Michael A; Stone, Lewi

    2003-01-01

    Cooperation among genetically unrelated individuals is commonly explained by the potential for future reciprocity or by the risk of being punished by group members. However, unconditional altruism is more difficult to explain. We demonstrate that unconditional altruism can evolve as a costly signal of individual quality (i.e. a handicap) as a consequence of reciprocal altruism. This is because the emergent correlation between altruism and individual quality in reciprocity games can facilitate the use of altruism as a quality indicator in a much wider context, outside the reciprocity game, thus affecting its further evolution through signalling benefits. Our model, based on multitype evolutionary game theory shows that, when the additive signalling benefit of donating help exceeds the cost for only some individuals (of high-quality state) but not for others (of low-quality state), the population possesses an evolutionarily stable strategy (ESS) profile wherein high-quality individuals cooperate unconditionally while low-quality individuals defect or play tit-for-tat (TfT). Hence, as predicted by Zahavi's handicap model, signalling benefits of altruistic acts can establish a stable generosity by high-quality individuals that no longer depends on the probability of future reciprocation or punishment. PMID:12590761

  20. Prosocial behaviour emerges independent of reciprocity in cottontop tamarins

    PubMed Central

    Cronin, Katherine A.; Schroeder, Kori K. E.; Snowdon, Charles T.

    2010-01-01

    The cooperative breeding hypothesis posits that cooperatively breeding species are motivated to act prosocially, that is, to behave in ways that provide benefits to others, and that cooperative breeding has played a central role in the evolution of human prosociality. However, investigations of prosocial behaviour in cooperative breeders have produced varying results and the mechanisms contributing to this variation are unknown. We investigated whether reciprocity would facilitate prosocial behaviour among cottontop tamarins, a cooperatively breeding primate species likely to engage in reciprocal altruism, by comparing the number of food rewards transferred to partners who had either immediately previously provided or denied rewards to the subject. Subjects were also tested in a non-social control condition. Overall, results indicated that reciprocity increased food transfers. However, temporal analyses revealed that when the tamarins' behaviour was evaluated in relation to the non-social control, results were best explained by (i) an initial depression in the transfer of rewards to partners who recently denied rewards, and (ii) a prosocial effect that emerged late in sessions independent of reciprocity. These results support the cooperative breeding hypothesis, but suggest a minimal role for positive reciprocity, and emphasize the importance of investigating proximate temporal mechanisms underlying prosocial behaviour. PMID:20630886

  1. Induction by gamma-radiation of DNA synthesis in radicle cells of germinating seeds of Pisum sativum l.

    PubMed

    Gudkov, I N; Grodzinsky, D M

    1976-05-01

    In radicle meristem cells of germinating seeds of the pea (Pisum sativum L) before the onset of replicative synthesis of DNA, irradiation with 2-3 krad of gamma-rays induced the incorporation of 3H-thymidine (3H-TdR). Maximum isotope incorporation was noted during the first 2 hours after irradiation. Higher doses of radiation suppressed 3H-TdR incorporation. It was not seen after gamma-irradiation of air-dried seeds, nor after fast-neutron irradiation. The replication inhibitors hydroxyurea and 5-aminouracil had no effect on the gamma-induced incorporation of 3H-TdR, Whereas caffeine and acriflavine inhibited it to some extent. It is suggested that the gamma-radiation-induced incorporation of 3H-TdR in meristem cells during the pre-replicative period may be connected with repair phenomena.

  2. Laboratory background of an escape-suppressed Clover gamma-ray detector overground, shallow underground, and deep underground

    SciTech Connect

    Szuecs, T.

    2010-03-01

    This study presents the laboratory background measurement of a Clover-type composite gamma-detector equipped with a BGO escape-suppression shield. Recently, such a detector had been used in an in-beam gamma-spectroscopy measurement of the {sup 14}N(p,gamma){sup 15}O reaction deep underground. Here the laboratory gamma-ray background of that detector is studied in three different environments: overground, in a shallow underground laboratory and deep underground. In addition, the effect of the escape-suppression shield on the cosmic-ray induced background has been studied in all three cases. The measurements have been performed at LUNA site in the Gran Sasso National Laboratory, Assergi, Italy (deep underground), at the Felsenkeller Laboratory, Dresden, Germany (shallow underground) and ATOMKI, Debrecen, Hungary (Earth's surface).

  3. Investigation on the Reciprocity Principle with In-Situ Pumping Test in Confined Aquifer

    NASA Astrophysics Data System (ADS)

    Chen, Yong-Lin; Lin, Hong-Ru; Huang, Shao-Yang; Yeh, Tian-Chyi J.; Wen, Jet-Chau

    2016-04-01

    In this study, the pumping test of reciprocity between wells is developed for 11 wells located on campus of NYUST. The reciprocity analysis is conducted with the heterogeneous hydraulic properties distributions of the site. The mathematical theory of reciprocity implies that choose one as stimulation point and the other as observed response point in two known points at the same random field. Repeat the above action, the response behavior should have the reciprocity between the two points. However, the lack of literature with the field experiment to prove that reciprocity principle. Therefore, this study is expected to investigate the reciprocity of drawdown with the pumping test which will have heterogeneous hydraulic properties distributions obtained by inverse process. In general, there are two ways to investigate the reciprocity of pumping tests of two wells. One way is to evaluate the drawdown reciprocity of two sequential wells. From the evaluation the reciprocity of the drawdown behavior during the sequential pumping wells, the reciprocity of the drawdown behavior is investigated. The other one is to estimate cross-correlation between the drawdown behavior of the sequential pumping wells and heterogeneous hydraulic properties distributions. The reciprocity of between the drawdown and the heterogeneous hydraulic properties distributions is therefore can be investigated. This study proved the reciprocity of drawdown with the sequential pumping test and heterogeneous hydraulic properties distributions obtained by inverse method. Meanwhile, we proved the reciprocity is existed during the pumping test in the confined aquifer. Keywords: Reciprocity, Cross-correlation, Confined aquifer, Stimulation, Response

  4. Increased interleukin-10 and interferon-γ levels in Plasmodium vivax malaria suggest a reciprocal regulation which is not altered by IL-10 gene promoter polymorphism

    PubMed Central

    2011-01-01

    Background In human malaria, the naturally-acquired immune response can result in either the elimination of the parasite or a persistent response mediated by cytokines that leads to immunopathology. The cytokines are responsible for all the symptoms, pathological alterations and the outcome of the infection depends on the reciprocal regulation of the pro and anti-inflammatory cytokines. IL-10 and IFN-gamma are able to mediate this process and their production can be affected by single nucleotide polymorphisms (SNPs) on gene of these cytokines. In this study, the relationship between cytokine IL-10/IFN-gamma levels, parasitaemia, and their gene polymorphisms was examined and the participation of pro-inflammatory and regulatory balance during a natural immune response in Plasmodium vivax-infected individuals was observed. Methods The serum levels of the cytokines IL-4, IL-12, IFN-gamma and IL-10 from 132 patients were evaluated by indirect enzyme-linked immunosorbent assays (ELISA). The polymorphism at position +874 of the IFN-gamma gene was identified by allele-specific polymerase chain reaction (ASO-PCR) method, and the polymorphism at position -1082 of the IL-10 gene was analysed by PCR-RFLP (PCR-Restriction Fragment Length Polymorphism). Results The levels of a pro- (IFN-gamma) and an anti-inflammatory cytokine (IL-10) were significantly higher in P. vivax-infected individuals as compared to healthy controls. The IFN-gamma levels in primoinfected patients were significantly higher than in patients who had suffered only one and more than one previous episode. The mutant alleles of both IFN-gamma and IL-10 genes were more frequent than the wild allele. In the case of the IFNG+874 polymorphism (IFN-gamma) the frequencies of the mutant (A) and wild (T) alleles were 70.13% and 29.87%, respectively. Similar frequencies were recorded in IL-10-1082, with the mutant (A) allele returning a frequency of 70.78%, and the wild (G) allele a frequency of 29.22%. The frequencies

  5. Dietary sugar beet fiber ameliorates diarrhea as an acute gamma-radiation injury in rats.

    PubMed

    Ishizuka, S; Ito, S; Kasai, T; Hara, H

    2000-09-01

    Gamma radiation induces diarrhea as an acute injury. We have studied whether ingestion of sugar beet fiber influences radiation-induced diarrhea. Abdominal irradiation with gamma rays induced diarrhea in male Wistar/ST rats from 2 to 7 days after a single sublethal dose. The body weight of the irradiated rats was decreased temporarily at 4 days after irradiation regardless of the ingestion of sugar beet fiber. At day 8, it returned to almost the same level as that of unirradiated rats. A change in daily food intake resulted in a pattern similar to that for body weight. Dietary sugar beet fiber had little significant effect on the changes in body weight and daily food intake, and its ingestion significantly decreased gamma-ray-induced diarrhea. Changes in biochemical and histological parameters in intestinal mucosa (small intestine, cecum and colon) were not greatly influenced by the ingestion of sugar beet fiber through the periods of diarrhea. It was concluded that dietary sugar beet fiber ameliorated the diarrhea induced by abdominal irradiation. We suggest that the inhibitory effect of the ingestion of sugar beet fiber is due to its effects on the luminal environment, such as support for bacterial function in the luminal contents in the colon of animals that ingest sugar beet fiber.

  6. Locomotion of a Reciprocal Swimmer by Fluid Elasticity

    NASA Astrophysics Data System (ADS)

    Keim, Nathan C.; Garcia, Mike; Arratia, Paulo E.

    2011-11-01

    When fluid response is entirely viscous, a swimmer performing a reciprocal motion achieves no net displacement. This form of time-reversal symmetry is commonly broken by a non-reciprocal swimming stroke, but it may also break down if the fluidic environment has a nonlinear viscoelastic response, as found in many natural media such as mucus. In this talk, we present experiments on a rigid dimer that is ``wiggled'' in a reciprocal motion by a magnetic field, in the vicinity of a wall. When the dimer is immersed in a viscoelastic fluid, its motion produces a net translation. Surprisingly, the dimer can swim in a direction that is primarily parallel to the wall. No net translation is seen in a viscous Newtonian fluid under the same conditions. We report the effect's dependence on Deborah number, swimming stroke, and geometric parameters. The underlying mechanism is examined with particle tracking measurements.

  7. Propulsion with a Reciprocal Stroke Enabled by Nonlinear Rheology

    NASA Astrophysics Data System (ADS)

    Arratia, Paulo; Shen, Xiaoning; Keim, Nathan

    2012-11-01

    In a fluid that is entirely viscous, a reciprocal swimming stroke results in no net displacement. However, complex fluids such as mucus or dense suspensions exhibit nonlinear rheology even at low Reynolds number. This nonlinear fluid response can lead to time-reversal symmetry breaking which can enable a reciprocal swimmer to move. Here we demonstrate this principle with a reciprocally-actuated artificial propeller in two viscoelastic fluids: a polymeric fluid with elasticity but negligible shear thinning, and a wormlike micellar fluid that exhibits shear thinning and shear-bands. Propulsion is absent in Newtonian fluid, and is strongest in the shear-thinning micellar fluid. We report on the role of elasticity (Deborah number) in setting the speed of propulsion, and of body shape and boundary conditions in setting its direction. This work is supported by the Army Research Office through award W911NF-11-1-0488.

  8. Reciprocal relations for effective conductivities of anisotropic media

    NASA Astrophysics Data System (ADS)

    Nevard, John; Keller, Joseph B.

    1985-11-01

    Any pair of two-dimensional anisotropic media with local conductivity tensors that are functions of position and that are related to one another in a certain reciprocal way are considered. It is proved that their effective conductivity tensors are related to each other in the same way for both spatially periodic media and statistically stationary random media. An inequality involving the effective conductivity tensors of two three-dimensional media that are reciprocally related is also proved. These results extend the corresponding results for locally isotropic media obtained by Keller, Mendelsohn, Hansen, Schulgasser, and Kohler and Papanicolau. They also yield a relation satisfied by the effective conductivity tensor of a medium reciprocal to a translated or rotated copy of itself.

  9. Repeated games and direct reciprocity under active linking.

    PubMed

    Pacheco, Jorge M; Traulsen, Arne; Ohtsuki, Hisashi; Nowak, Martin A

    2008-02-21

    Direct reciprocity relies on repeated encounters between the same two individuals. Here we examine the evolution of cooperation under direct reciprocity in dynamically structured populations. Individuals occupy the vertices of a graph, undergoing repeated interactions with their partners via the edges of the graph. Unlike the traditional approach to evolutionary game theory, where individuals meet at random and have no control over the frequency or duration of interactions, we consider a model in which individuals differ in the rate at which they seek new interactions. Moreover, once a link between two individuals has formed, the productivity of this link is evaluated. Links can be broken off at different rates. Whenever the active dynamics of links is sufficiently fast, population structure leads to a simple transformation of the payoff matrix, effectively changing the game under consideration, and hence paving the way for reciprocators to dominate defectors. We derive analytical conditions for evolutionary stability.

  10. Non-reciprocal elastic wave propagation in spatiotemporal periodic structures

    NASA Astrophysics Data System (ADS)

    Trainiti, G.; Ruzzene, M.

    2016-08-01

    We study longitudinal and transverse wave propagation in beams with elastic properties that are periodically varying in space and time. Spatiotemporal modulation of the elastic properties breaks mechanical reciprocity and induces one-way propagation. We follow an analytic approach to characterize the non-reciprocal behavior of the structures by analyzing the symmetry breaking of the dispersion spectrum, which results in the formation of directional band gaps and produces shifts of the first Brillouin zone limits. This approach allows us to relate position and width of the directional band gaps to the modulation parameters. Moreover, we identify the critical values of the modulation speed to maximize the non-reciprocal effect. We numerically verify the theoretical predictions by using a finite element model of the modulated beams to compute the transient response of the structure. We compute the two-dimensional Fourier transform of the collected displacement fields to calculate numerical band diagrams, showing excellent agreement between theoretical and numerical dispersion diagrams.

  11. Means and method of balancing multi-cylinder reciprocating machines

    DOEpatents

    Corey, John A.; Walsh, Michael M.

    1985-01-01

    A virtual balancing axis arrangement is described for multi-cylinder reciprocating piston machines for effectively balancing out imbalanced forces and minimizing residual imbalance moments acting on the crankshaft of such machines without requiring the use of additional parallel-arrayed balancing shafts or complex and expensive gear arrangements. The novel virtual balancing axis arrangement is capable of being designed into multi-cylinder reciprocating piston and crankshaft machines for substantially reducing vibrations induced during operation of such machines with only minimal number of additional component parts. Some of the required component parts may be available from parts already required for operation of auxiliary equipment, such as oil and water pumps used in certain types of reciprocating piston and crankshaft machine so that by appropriate location and dimensioning in accordance with the teachings of the invention, the virtual balancing axis arrangement can be built into the machine at little or no additional cost.

  12. A multiplexed immunoassay system based upon reciprocating centrifugal microfluidics

    NASA Astrophysics Data System (ADS)

    Noroozi, Zahra; Kido, Horacio; Peytavi, Régis; Nakajima-Sasaki, Rie; Jasinskas, Algimantas; Micic, Miodrag; Felgner, Philip L.; Madou, Marc J.

    2011-06-01

    A novel, centrifugal disk-based micro-total analysis system (μTAS) for low cost and high throughput semi-automated immunoassay processing was developed. A key innovation in the disposable immunoassay disk design is in a fluidic structure that enables very efficient micro-mixing based on a reciprocating mechanism in which centrifugal acceleration acting upon a liquid element first generates and stores pneumatic energy that is then released by a reduction of the centrifugal acceleration, resulting in a reversal of direction of flow of the liquid. Through an alternating sequence of high and low centrifugal acceleration, the system reciprocates the flow of liquid within the disk to maximize incubation/hybridization efficiency between antibodies and antigen macromolecules during the incubation/hybridization stage of the assay. The described reciprocating mechanism results in a reduction in processing time and reagent consumption by one order of magnitude.

  13. Chimpanzees trust conspecifics to engage in low-cost reciprocity

    PubMed Central

    Engelmann, Jan M.; Herrmann, Esther; Tomasello, Michael

    2015-01-01

    Many of humans' most important social interactions rely on trust, including most notably among strangers. But little is known about the evolutionary roots of human trust. We presented chimpanzees (Pan troglodytes) with a modified version of the human trust game—trust in reciprocity—in which subjects could opt either to obtain a small but safe reward on their own or else to send a larger reward to a partner and trust her to reciprocate a part of the reward that she could not access herself. In a series of three studies, we found strong evidence that in interacting with a conspecific, chimpanzees show spontaneous trust in a novel context; flexibly adjust their level of trust to the trustworthiness of their partner and develop patterns of trusting reciprocity over time. At least in some contexts then, trust in reciprocity is not unique to humans, but rather has its evolutionary roots in the social interactions of humans' closest primate relatives. PMID:25589606

  14. Reciprocal Space Mapping of Macromolecular Crystals in the Home Laboratory

    NASA Technical Reports Server (NTRS)

    Snell, Edward H.; Fewster, P. F.; Andrew, Norman; Boggon, T. J.; Judge, Russell A.; Pusey, Marc A.

    1999-01-01

    Reciprocal space mapping techniques are used widely by the materials science community to provide physical information about their crystal samples. We have used similar methods at synchrotron sources to look at the quality of macromolecular crystals produced both on the ground and under microgravity conditions. The limited nature of synchrotron time has led us to explore the use of a high resolution materials research diffractometer to perform similar measurements in the home laboratory. Although the available intensity is much reduced due to the beam conditioning necessary for high reciprocal space resolution, lower resolution data can be collected in the same detail as the synchrotron source. Experiments can be optimized at home to make most benefit from the synchrotron time available. Preliminary results including information on the mosaicity and the internal strains from reciprocal space maps will be presented.

  15. Reciprocal feeding facilitation between above- and below-ground herbivores

    PubMed Central

    McKenzie, Scott W.; Vanbergen, Adam J.; Hails, Rosemary S.; Jones, T. Hefin; Johnson, Scott N.

    2013-01-01

    Interspecific interactions between insect herbivores predominantly involve asymmetric competition. By contrast, facilitation, whereby herbivory by one insect benefits another via induced plant susceptibility, is uncommon. Positive reciprocal interactions between insect herbivores are even rarer. Here, we reveal a novel case of reciprocal feeding facilitation between above-ground aphids (Amphorophora idaei) and root-feeding vine weevil larvae (Otiorhynchus sulcatus), attacking red raspberry (Rubus idaeus). Using two raspberry cultivars with varying resistance to these herbivores, we further demonstrate that feeding facilitation occurred regardless of host plant resistance. This positive reciprocal interaction operates via an, as yet, unreported mechanism. Specifically, the aphid induces compensatory growth, possibly as a prelude to greater resistance/tolerance, whereas the root herbivore causes the plant to abandon this strategy. Both herbivores may ultimately benefit from this facilitative interaction. PMID:23883576

  16. Evaluation of non-reciprocal heterologous immunity between unrelated viruses.

    PubMed

    Che, Jenny W; Selin, Liisa K; Welsh, Raymond M

    2015-08-01

    Heterologous immunity refers to the phenomenon whereby a history of an immune response against one pathogen can provide a level of immunity to a second unrelated pathogen. Previous investigations have shown that heterologous immunity is not necessarily reciprocal, such as in the case of vaccinia virus (VACV). Replication of VACV is reduced in mice immune to a variety of pathogens, while VACV fails to induce immunity to several of the same pathogens, including lymphocytic choriomeningitis virus (LCMV). Here we examine the lack of reciprocity of heterologous immunity between VACV and LCMV and find that they induce qualitatively different memory CD8 T cells. However, depending on the repertoire of an individual host, VACV can provide protection against LCMV simply by experimentally amplifying the quantity of T cells cross-reactive with the two viruses. Thus, one cause for lack of reciprocity is differences in the frequencies of cross-reactive T cells in immune hosts.

  17. [Without reciprocal recognition there is not quality of care].

    PubMed

    Calvo Rigual, Fernando; Costa Alcaraz, Ana M; García-Conde Brú, Javier; Megía Sanz, María Jesús

    2011-10-01

    Understanding the classic doctor-patient relationship has entered a crisis in medicine today. Communication difficulties, underestimation of empathy, or bringing economic criteria are leading to care styles that facilitate the objectification of patients, contempt for doctors, and indifference of both to collective measures of health. Basic principles of this relationship such as quality, justice, patient autonomy and beneficence may appear weak content. We intend to apply the concept of "reciprocal recognition" from philosophy to "recharge" content different aspects of the clinical relationship: a look "inside", dealing with the identity of the protagonists seek to promote it by using reciprocal recognition of both patient and the professional. In one aspect "external", focusing on the quality of care, a key objective of the clinical relationship. With reciprocal recognition, issues of justice and equity are reinforced through public health, building an identity of citizens with rights.

  18. The evolution of generalized reciprocity in social interaction networks.

    PubMed

    Voelkl, Bernhard

    2015-09-01

    Generalized reciprocity has been proposed as a mechanism for enabling continued cooperation between unrelated individuals. It can be described by the simple rule "help somebody if you received help from someone", and as it does not require individual recognition, complex cognition or extended memory capacities, it has the potential to explain cooperation in a large number of organisms. In a panmictic population this mechanism is vulnerable to defection by individuals who readily accept help but do not help themselves. Here, I investigate to what extent the limitation of social interactions to a social neighborhood can lead to conditions that favor generalized reciprocity in the absence of population structuring. It can be shown that cooperation is likely to evolve if one assumes certain sparse interaction graphs, if strategies are discrete, and if spontaneous helping and reciprocating are independently inherited.

  19. Children’s Beliefs in Reciprocation of Biases and Flexibility

    PubMed Central

    Rennels, Jennifer L.

    2015-01-01

    Children display positive and negative biases based on peers’ attractiveness, gender, and race, but it is unclear whether children who associate positive attributes with certain peers also believe those peers think positively of them. In each domain (attractiveness, gender, race), we measured 3- to 11-year-olds’ (N=102) biases and flexibility and their beliefs in reciprocity of bias and flexibility by asking who would think positively of them. Children could choose one of two unfamiliar peers (forced choice assessment) or had the additional options of choosing both or neither peer (non-forced choice assessment). We found children often displayed beliefs in reciprocation, with beliefs in positive bias reciprocation from attractive girls showing the largest effect sizes. These beliefs significantly correlated with and were predictive of children’s positive and negative biases and flexibility. The duality of children’s beliefs may contribute to strengthening their biases and segregating social groups. PMID:25918015

  20. Spatially correlated heterogeneous aspirations to enhance network reciprocity

    NASA Astrophysics Data System (ADS)

    Tanimoto, Jun; Nakata, Makoto; Hagishima, Aya; Ikegaya, Naoki

    2012-02-01

    Perc & Wang demonstrated that aspiring to be the fittest under conditions of pairwise strategy updating enhances network reciprocity in structured populations playing 2×2 Prisoner's Dilemma games (Z. Wang, M. Perc, Aspiring to the fittest and promoted of cooperation in the Prisoner's Dilemma game, Physical Review E 82 (2010) 021115; M. Perc, Z. Wang, Heterogeneous aspiration promotes cooperation in the Prisoner's Dilemma game, PLOS one 5 (12) (2010) e15117). Through numerical simulations, this paper shows that network reciprocity is even greater if heterogeneous aspirations are imposed. We also suggest why heterogeneous aspiration fosters network reciprocity. It distributes strategy updating speed among agents in a manner that fortifies the initially allocated cooperators' clusters against invasion. This finding prompted us to further enhance the usual heterogeneous aspiration cases for heterogeneous network topologies. We find that a negative correlation between degree and aspiration level does extend cooperation among heterogeneously structured agents.

  1. Physiological and molecular characterization of the enhanced salt tolerance induced by low-dose gamma irradiation in Arabidopsis seedlings

    SciTech Connect

    Qi, Wencai; Zhang, Liang; Xu, Hangbo; Wang, Lin; Jiao, Zhen

    2014-07-25

    Highlights: • 50-Gy gamma irradiation markedly promotes the seedling growth under salt stress in Arabidopsis. • The contents of H{sub 2}O{sub 2} and MDA are obviously reduced by low-dose gamma irradiation under salt stress. • Low-dose gamma irradiation stimulates the activities of antioxidant enzymes under salt stress. • Proline accumulation is required for the low-gamma-ray-induced salt tolerance. • Low gamma rays differentially regulate the expression of genes related to salt stress. - Abstract: It has been established that gamma rays at low doses stimulate the tolerance to salt stress in plants. However, our knowledge regarding the molecular mechanism underlying the enhanced salt tolerance remains limited. In this study, we found that 50-Gy gamma irradiation presented maximal beneficial effects on germination index and root length in response to salt stress in Arabidopsis seedlings. The contents of H{sub 2}O{sub 2} and MDA in irradiated seedlings under salt stress were significantly lower than those of controls. The activities of antioxidant enzymes and proline levels in the irradiated seedlings were markedly increased compared with the controls. Furthermore, transcriptional expression analysis of selected genes revealed that some components of salt stress signaling pathways were stimulated by low-dose gamma irradiation under salt stress. Our results suggest that gamma irradiation at low doses alleviates the salt stress probably by modulating the physiological responses as well as stimulating the stress signal transduction in Arabidopsis seedlings.

  2. Role of x-ray-induced transcripts in adaptive responses following x-rays. Progress report, year 1

    SciTech Connect

    Boothman, D.A.

    1992-09-01

    Potentially lethal damage repair (PLDR) and sublethal damage repair, may be the same manifestations of a series of common enzymatic steps. PLDR, has two distinct phases based upon DNA lesion repair and survival recovery studies. The first phase of PLDR occurs very quickly (t{sub {1/2}}:2--20 mins) to increase the survival of X-irradiated cells by mending the vast array of DNA lesions created by ionizing radiation. The second slower phase of PLDR proceeds much later (i.e., >1--2 hrs) following X-irradiation, during which the remaining double-stranded DNA breaks are completely repaired. This second phase of repair closely corresponds to the restructuring of gross chromosomal damage, and can be partially blocked in some human cells by inhibiting protein synthesis. This slower phase of PLDR correlated with a rapid decline in X-ray-induced transformation of normal cells. The fast component of PLDR may be due to constitutively synthesized DNA ligases, topoisomerases, or polymerases, which act immediately to repair damaged, DNA. In contrast, the slow phase of PLDR in human cells may require the induction of specific genes and gene product`s involved in the repair of potentially lethal or carcinogenic DNA lesions. Induced gene products (i.e., proteins) specifically synthesized in response to physiological doses of ionizing radiation in radioresistant human melanoma (U1-Mel) cells, and in a variety of other human normal and cancer-prone cells, were identified using two-dimensional gel electrophoresis. We identified and partially characterized ten proteins synthesized by U1-Mel cells. The synthesis of eight of these proteins were specifically induced by ionizing radiation and two proteins were repressed Neither heat shock, UV-irradiation, nor bifunctional alkylating agent treatments resulted in the induction of these proteins. The expression of one protein, XIP269, correlated very well with PLDR capacity.

  3. Exogenous Nitric Oxide Suppresses in Vivo X-ray-Induced Targeted and Non-Targeted Effects in Zebrafish Embryos

    PubMed Central

    Kong, E.Y.; Yeung, W.K.; Chan, T.K.Y.; Cheng, S.H.; Yu, K.N.

    2016-01-01

    The present paper studied the X-ray-induced targeted effect in irradiated zebrafish embryos (Danio rerio), as well as a non-targeted effect in bystander naïve embryos partnered with irradiated embryos, and examined the influence of exogenous nitric oxide (NO) on these targeted and non-targeted effects. The exogenous NO was generated using an NO donor, S-nitroso-N-acetylpenicillamine (SNAP). The targeted and non-targeted effects, as well as the toxicity of the SNAP, were assessed using the number of apoptotic events in the zebrafish embryos at 24 h post fertilization (hpf) revealed through acridine orange (AO) staining. SNAP with concentrations of 20 and 100 µM were first confirmed to have no significant toxicity on zebrafish embryos. The targeted effect was mitigated in zebrafish embryos if they were pretreated with 100 µM SNAP prior to irradiation with an X-ray dose of 75 mGy but was not alleviated in zebrafish embryos if they were pretreated with 20 µM SNAP. On the other hand, the non-targeted effect was eliminated in the bystander naïve zebrafish embryos if they were pretreated with 20 or 100 µM SNAP prior to partnering with zebrafish embryos having been subjected to irradiation with an X-ray dose of 75 mGy. These findings revealed the importance of NO in the protection against damages induced by ionizing radiations or by radiation-induced bystander signals, and could have important impacts on development of advanced cancer treatment strategies. PMID:27529238

  4. Exogenous Nitric Oxide Suppresses in Vivo X-ray-Induced Targeted and Non-Targeted Effects in Zebrafish Embryos.

    PubMed

    Kong, E Y; Yeung, W K; Chan, T K Y; Cheng, S H; Yu, K N

    2016-01-01

    The present paper studied the X-ray-induced targeted effect in irradiated zebrafish embryos (Danio rerio), as well as a non-targeted effect in bystander naïve embryos partnered with irradiated embryos, and examined the influence of exogenous nitric oxide (NO) on these targeted and non-targeted effects. The exogenous NO was generated using an NO donor, S-nitroso-N-acetylpenicillamine (SNAP). The targeted and non-targeted effects, as well as the toxicity of the SNAP, were assessed using the number of apoptotic events in the zebrafish embryos at 24 h post fertilization (hpf) revealed through acridine orange (AO) staining. SNAP with concentrations of 20 and 100 µM were first confirmed to have no significant toxicity on zebrafish embryos. The targeted effect was mitigated in zebrafish embryos if they were pretreated with 100 µM SNAP prior to irradiation with an X-ray dose of 75 mGy but was not alleviated in zebrafish embryos if they were pretreated with 20 µM SNAP. On the other hand, the non-targeted effect was eliminated in the bystander naïve zebrafish embryos if they were pretreated with 20 or 100 µM SNAP prior to partnering with zebrafish embryos having been subjected to irradiation with an X-ray dose of 75 mGy. These findings revealed the importance of NO in the protection against damages induced by ionizing radiations or by radiation-induced bystander signals, and could have important impacts on development of advanced cancer treatment strategies. PMID:27529238

  5. Negative reciprocity and communication in couples with a violent husband.

    PubMed

    Cordova, J V; Jacobson, N S; Gottman, J M; Rushe, R; Cox, G

    1993-11-01

    To better understand the relationship dynamics of couples experiencing husband-to-wife violence, the interaction patterns of 29 domestically violent (DV), 15 distressed but nonviolent (DNV), and 13 happily married (HM) couples were examined using the Marital Interaction Coding System and lag sequential analyses. DV spouses were generally more often aversive and less often facilitative than nonviolent couples. DV couples were significantly more likely to engage in negative reciprocity than their DNV or their HM counterparts. DV wives were as likely as their husbands to reciprocate negative behavior. Furthermore, no support was found for a negative reinforcement hypothesis that husbands' aversiveness was shaped or maintained by wives' capitulation. PMID:8282924

  6. Design tradeoffs of a reciprocating auxiliary power unit

    NASA Astrophysics Data System (ADS)

    Renquist, Jacob Vinod

    This thesis presents a comparison of reciprocating auxiliary power units to conventional, gas turbine auxiliary power units. A metric of interest is created to represent the specific auxiliary power system weight including the prime mover, generator, gearbox, and fuel consumed. The metric of interest is used to compare the different auxiliary power unit technologies by incorporating detailed engine simulations, auxiliary power unit system weight modeling, and flight path-realized fuel consumption modeling. Results show that reciprocating auxiliary power units can be competitive with gas turbines in near-term, more-electric aircraft applications.

  7. Ubiquity of Benford's law and emergence of the reciprocal distribution

    NASA Astrophysics Data System (ADS)

    Friar, J. L.; Goldman, T.; Pérez-Mercader, J.

    2016-05-01

    We apply the Law of Total Probability to the construction of scale-invariant probability distribution functions (pdf's), and require that probability measures be dimensionless and unitless under a continuous change of scales. If the scale-change distribution function is scale invariant then the constructed distribution will also be scale invariant. Repeated application of this construction on an arbitrary set of (normalizable) pdf's results again in scale-invariant distributions. The invariant function of this procedure is given uniquely by the reciprocal distribution, suggesting a kind of universality. We separately demonstrate that the reciprocal distribution results uniquely from requiring maximum entropy for size-class distributions with uniform bin sizes.

  8. The Harvard Catalyst Common Reciprocal IRB Reliance Agreement

    PubMed Central

    Winkler, Sabune J.; Witte, Elizabeth; Bierer, Barbara E.

    2014-01-01

    Reduction of duplicative Institutional Review Board (IRB) review for multi-institutional studies is a desirable goal to improve IRB efficiency while enhancing human subject protections. Here we describe the Harvard Catalyst Master Reciprocal Common IRB Reliance Agreement (MRA), a system that provides a legal framework for IRB reliance, with the potential to streamline IRB review processes and reduce administrative burden and barriers to collaborative, multi-institutional research. The MRA respects the legal autonomy of the signatory institutions while offering a pathway to eliminate duplicative IRB review when appropriate. The Harvard Catalyst MRA provides a robust and flexible model for reciprocal reliance that is both adaptable and scalable. PMID:25196592

  9. Cellular proliferation in the skin of X-rayed newt limbs (with a note on x-ray-induced limb regression)

    SciTech Connect

    Wertz, R.L.

    1982-07-01

    Left hind limbs, including the pelvis, of adult newts (Notophthalmus viridescens) were locally irradiated with a dose of x-rays that inhibited regeneration (2,000 R). This x-ray dose and other doses (700-2,000 R) capable of inhibiting limb regeneration also cause limb regression prior to amputation. Before limb regression occurred, there was a latent period of 3 to 6 weeks. Limb regression was characterized by necrotic wasting and resorption of distal elements. The degree of loss was variable and dependent upon dosage. After this further degenerative changes were not noted. Proliferation of epidermal cells was examined 4 days after irradiation prior to limb regression or after x-ray-induced degeneration of the limbs had ended. Proliferative activity in x-rayed limbs was also compared at various stages of contralateral control limb regeneration. Limbs examined after x-ray-induced limb regression had ended showed levels of (/sup 3/H)-thymidine incorporation into DNA comparable to normal epidermis. In contrast, limbs examined 4 days after irradiation had lower levels of DNA synthesis (P much less than 0.01). Amputation of limbs in both groups caused an increase in DNA synthesis (P much less than 0.01). Histological examination showed that cellular proliferation was associated primarily with the epidermis. These results indicate that epidermal cell proliferation was not resistant to x-rays. However, levels of normal cell division were observed after amputation of after cessation of x-ray-induced limb regression.

  10. IL-4 and interferon-gamma production in children with atopic disease.

    PubMed Central

    Tang, M; Kemp, A; Varigos, G

    1993-01-01

    In vitro studies have implicated reciprocal roles for IL-4 and interferon-gamma (IFN-gamma) in the regulation of IgE production. As elevated IgE is a major feature of atopic disease, an important question is whether an imbalance of IL-4 and IFN-gamma is present in vivo. The production of IL-4 and IFN-gamma in phytohaemagglutinin (PHA)-stimulated peripheral blood mononuclear cell cultures from atopic children was examined to determine if there is an increased production of IL-4 and/or a reduced production of IFN-gamma. Highly atopic children with IgE > 600 U/ml produced significantly more IL-4 and less IFN-gamma in vitro than age-matched non-atopic controls. Production of IL-4 and IFN-gamma in mildly atopic children was equivalent to controls. These findings indicate that highly atopic children have an imbalance of IL-4 and IFN-gamma production and that the degree of imbalance relates to severity of the atopic state. The ratio of in vitro IL-4: IFN-gamma production correlated positively with serum IgE, which suggests that the balance of these two cytokines is a factor in the regulation of IgE, in vivo. It remains to be determined whether this imbalance of IL-4 and IFN-gamma in the highly atopic children is the cause or result of the disease process. PMID:8467557

  11. gamma-Hexachlorocyclohexane (gamma-HCH)

    Integrated Risk Information System (IRIS)

    gamma - Hexachlorocyclohexane ( gamma - HCH ) ; CASRN 58 - 89 - 9 Human health assessment information on a chemical substance is included in the IRIS database only after a comprehensive review of toxicity data , as outlined in the IRIS assessment development process . Sections I ( Health Hazard Asse

  12. 77 FR 60341 - National Emission Standards for Hazardous Air Pollutants for Reciprocating Internal Combustion...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-10-03

    ... Source Performance Standards for Stationary Internal Combustion Engines'' (77 FR 33812). The June 7, 2012... Reciprocating Internal Combustion Engines; New Source Performance Standards for Stationary Internal Combustion... Emission Standards for Hazardous Air Pollutants for Stationary Reciprocating Internal......

  13. 75 FR 80761 - National Emission Standards for Hazardous Air Pollutants for Reciprocating Internal Combustion...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-12-23

    ... Reciprocating Internal Combustion Engines AGENCY: Environmental Protection Agency (EPA). ACTION: Notice of... air pollutants for reciprocating internal combustion engines and requesting public comment on one... the limitations on operation of emergency stationary engines to allow emergency engines to operate...

  14. Reciprocal Teaching of Comprehension Strategies Improves EFL Learners' Writing Ability

    ERIC Educational Resources Information Center

    Ghorbani, Mohammad Reza; Gangeraj, Atefeh Ardeshir; Alavi, Sahar Zahed

    2013-01-01

    Although the importance of reading in developing writing ability is undeniable, few competent readers in EFL contexts develop into competent writers. Since students are not aware that reading can assist them in writing, this study examined the effect of reciprocal teaching--which focuses on four reading comprehension strategies, namely…

  15. Reciprocal Category Analysis in Major Fields of Psychotherapy.

    ERIC Educational Resources Information Center

    Morgan, Clifford O.; Stricherz, Mathias E.

    Client-therapist verbal interaction in content analysis research has just begun to be defined. Reciprocal Category Analysis (RCA) is used to measure therapeutic interactions between client and therapist. Three experienced therapists from each of the schools of client-centered, Rational Emotive (RET), Transactional Analysis (TA), and Gestalt…

  16. The Reciprocal Organization of Constructive Activity in Drug Addiction

    ERIC Educational Resources Information Center

    Akhmetzyanova, Anna I.; Nikishina, Vera B.; Klyueva, Nadezhda V.; Petrash, Ekaterina A.

    2016-01-01

    The urgency of the problem stated in the article is caused by the fact that modern scientific studies show that sustainable neuro-associative connections with the object of addiction arise at chemical addiction. The aim of this study is to examine the features of the reciprocal organization of constructive activities in drug addiction. Study of…

  17. Peer Relations of Learning Disabled Children: A Reciprocity Model.

    ERIC Educational Resources Information Center

    Wiener, Judith; Harris, P. J.

    1989-01-01

    A study of 90 learning-disabled and 94 nonlearning-disabled students, aged 9-12, found that the peer status of subjects was related to their social behavior and to their placement in the school system. These findings lend support for Judith Wiener's Reciprocity Model of Peer Status. (Author/JDD)

  18. Monkeys fail to reciprocate in an exchange task.

    PubMed

    Pelé, Marie; Thierry, Bernard; Call, Josep; Dufour, Valérie

    2010-09-01

    Exchanges form the basis of human economies. Animals too can engage in reciprocal interactions but they do not barter goods like humans, which raises the question of the abilities necessary for trading to occur. Previous studies have shown that non-human primates can exchange food with human partners. Here, we tested the ability of brown capuchin monkeys and Tonkean macaques to reciprocate in a task requiring two conspecifics to exchange tokens in order to obtain rewards from an experimenter. We recorded 56 transfers between subjects in capuchin monkeys and 10 in Tonkean macaques. All transfers were passive in both species. Capuchins preferentially picked up tokens valuable for them in the partner's compartment. They tended to manipulate the partner-valued tokens more often than the no-value ones, leading to more opportunities for these tokens to end up within reach of the partner. Despite optimal conditions where values of goods were defined and known by partners, however, none of the pairs tested engaged in short-term reciprocal interactions. These results indicate that calculated reciprocity was difficult if not impossible in the animals tested. PMID:20473699

  19. Perspectives from ethnography on weak and strong reciprocity.

    PubMed

    Wiessner, Polly

    2012-02-01

    To add ethnographic perspective to Guala's arguments, I suggest reasons why experimental and ethnographic evidence do not concur and highlight some difficulties in measuring whether positive and negative reciprocity are indeed costly. I suggest that institutions to reduce the costs of maintaining cooperation are not limited to complex societies.

  20. Coaction versus reciprocity in continuous-time models of cooperation.

    PubMed

    van Doorn, G Sander; Riebli, Thomas; Taborsky, Michael

    2014-09-01

    Cooperating animals frequently show closely coordinated behaviours organized by a continuous flow of information between interacting partners. Such real-time coaction is not captured by the iterated prisoner's dilemma and other discrete-time reciprocal cooperation games, which inherently feature a delay in information exchange. Here, we study the evolution of cooperation when individuals can dynamically respond to each other's actions. We develop continuous-time analogues of iterated-game models and describe their dynamics in terms of two variables, the propensity of individuals to initiate cooperation (altruism) and their tendency to mirror their partner's actions (coordination). These components of cooperation stabilize at an evolutionary equilibrium or show oscillations, depending on the chosen payoff parameters. Unlike reciprocal altruism, cooperation by coaction does not require that those willing to initiate cooperation pay in advance for uncertain future benefits. Correspondingly, we show that introducing a delay to information transfer between players is equivalent to increasing the cost of cooperation. Cooperative coaction can therefore evolve much more easily than reciprocal cooperation. When delays entirely prevent coordination, we recover results from the discrete-time alternating prisoner's dilemma, indicating that coaction and reciprocity are connected by a continuum of opportunities for real-time information exchange.

  1. Explaining Cooperation in Groups: Testing Models of Reciprocity and Learning

    ERIC Educational Resources Information Center

    Biele, Guido; Rieskamp, Jorg; Czienskowski, Uwe

    2008-01-01

    What are the cognitive processes underlying cooperation in groups? This question is addressed by examining how well a reciprocity model, two learning models, and social value orientation can predict cooperation in two iterated n-person social dilemmas with continuous contributions. In the first of these dilemmas, the public goods game,…

  2. Tag-based indirect reciprocity by incomplete social information.

    PubMed

    Masuda, Naoki; Ohtsuki, Hisashi

    2007-03-01

    Evolution of altruistic behaviour in interacting individuals is accounted for by, for example, kin selection, direct reciprocity, spatially limited interaction and indirect reciprocity. Real social agents, particularly humans, often take actions based on similarity between themselves and others. Although tag-based indirect reciprocity in which altruism occurs exclusively among similar flocks is a natural expectation, its mechanism has not really been established. We propose a model of tag-based indirect reciprocity by assuming that each player may note strategies of others. We show that tag-based altruism can evolve to eradicate other strategies, including unconditional defectors for various initial strategy configurations and parameter sets. A prerequisite for altruism is that the strategy is sometimes, but not always, visible to others. Without visibility of strategies, policing does not take place and defection is optimal. With perfect visibility, what a player does is always witnessed by others and cooperation is optimal. In the intermediate regime, discriminators based on tag proximity, rather than mixture of generous players and defectors, are most likely to evolve. In this situation, altruism is realized based on homophily in which players are exclusively good to similar others.

  3. A rapid, precise, reciprocating-movement color filter system

    NASA Technical Reports Server (NTRS)

    Phillipps, P. G.; Epstein, P.; Donovan, G.; Lawhite, E.

    1972-01-01

    Unit was designed for moving color filters in and out of position in less than 46 ms. System may be used to record previously derived colors on photorecorder or to scan different color or wavelength components of rapidly passing scene, as in aerial reconnaissance. Rapid, precise reciprocating movement may be useful in purely mechanical and chemical applications.

  4. Boredom and Academic Achievement: Testing a Model of Reciprocal Causation

    ERIC Educational Resources Information Center

    Pekrun, Reinhard; Hall, Nathan C.; Goetz, Thomas; Perry, Raymond P.

    2014-01-01

    A theoretical model linking boredom and academic achievement is proposed. Based on Pekrun's (2006) control-value theory of achievement emotions, the model posits that boredom and achievement reciprocally influence each other over time. Data from a longitudinal study with college students (N = 424) were used to examine the hypothesized effects. The…

  5. Generation of the reciprocal-binomial state for optical fields

    NASA Astrophysics Data System (ADS)

    Valverde, C.; Avelar, A. T.; Baseia, B.; Malbouisson, J. M. C.

    2003-08-01

    We compare the efficiencies of two interesting schemes to generate truncated states of the light field in running modes, namely the “quantum scissors” and the “beam-splitter array” schemes. The latter is applied to create the reciprocal-binomial state as a travelling wave, required to implement recent experimental proposals of phase-distribution determination and of quantum lithography.

  6. Reciprocal and Inversion Reversibility in Language Acquisition and Cognitive Development.

    ERIC Educational Resources Information Center

    Flora, June Annette

    Kindergarten and first-grade children participated in a study of the role of reciprocal and inversion reversibility in language acquisition and cognitive development. Subjects completed cognitive tasks assessing conservation, seriation, and class inclusion, and language tasks assessing the active-passive transformation and the negative…

  7. Perspectives from ethnography on weak and strong reciprocity.

    PubMed

    Wiessner, Polly

    2012-02-01

    To add ethnographic perspective to Guala's arguments, I suggest reasons why experimental and ethnographic evidence do not concur and highlight some difficulties in measuring whether positive and negative reciprocity are indeed costly. I suggest that institutions to reduce the costs of maintaining cooperation are not limited to complex societies. PMID:22289335

  8. Reciprocal Teaching of Lecture Comprehension Skills in College Students

    ERIC Educational Resources Information Center

    Spivey, Norman R.; Cuthbert, Andrea

    2006-01-01

    This study explored the effects of a reciprocal teaching intervention designed to enhance the lecture comprehension skills of college students. Forty low-verbal ability students and 40 high-verbal ability students (as measured by SAT scores) were chosen for the study and randomly assigned to experimental or control groups. The experimental groups…

  9. Modeling time-lagged reciprocal psychological empowerment-performance relationships.

    PubMed

    Maynard, M Travis; Luciano, Margaret M; D'Innocenzo, Lauren; Mathieu, John E; Dean, Matthew D

    2014-11-01

    Employee psychological empowerment is widely accepted as a means for organizations to compete in increasingly dynamic environments. Previous empirical research and meta-analyses have demonstrated that employee psychological empowerment is positively related to several attitudinal and behavioral outcomes including job performance. While this research positions psychological empowerment as an antecedent influencing such outcomes, a close examination of the literature reveals that this relationship is primarily based on cross-sectional research. Notably, evidence supporting the presumed benefits of empowerment has failed to account for potential reciprocal relationships and endogeneity effects. Accordingly, using a multiwave, time-lagged design, we model reciprocal relationships between psychological empowerment and job performance using a sample of 441 nurses from 5 hospitals. Incorporating temporal effects in a staggered research design and using structural equation modeling techniques, our findings provide support for the conventional positive correlation between empowerment and subsequent performance. Moreover, accounting for the temporal stability of variables over time, we found support for empowerment levels as positive influences on subsequent changes in performance. Finally, we also found support for the reciprocal relationship, as performance levels were shown to relate positively to changes in empowerment over time. Theoretical and practical implications of the reciprocal psychological empowerment-performance relationships are discussed. (PsycINFO Database Record (c) 2014 APA, all rights reserved).

  10. Modeling time-lagged reciprocal psychological empowerment-performance relationships.

    PubMed

    Maynard, M Travis; Luciano, Margaret M; D'Innocenzo, Lauren; Mathieu, John E; Dean, Matthew D

    2014-11-01

    Employee psychological empowerment is widely accepted as a means for organizations to compete in increasingly dynamic environments. Previous empirical research and meta-analyses have demonstrated that employee psychological empowerment is positively related to several attitudinal and behavioral outcomes including job performance. While this research positions psychological empowerment as an antecedent influencing such outcomes, a close examination of the literature reveals that this relationship is primarily based on cross-sectional research. Notably, evidence supporting the presumed benefits of empowerment has failed to account for potential reciprocal relationships and endogeneity effects. Accordingly, using a multiwave, time-lagged design, we model reciprocal relationships between psychological empowerment and job performance using a sample of 441 nurses from 5 hospitals. Incorporating temporal effects in a staggered research design and using structural equation modeling techniques, our findings provide support for the conventional positive correlation between empowerment and subsequent performance. Moreover, accounting for the temporal stability of variables over time, we found support for empowerment levels as positive influences on subsequent changes in performance. Finally, we also found support for the reciprocal relationship, as performance levels were shown to relate positively to changes in empowerment over time. Theoretical and practical implications of the reciprocal psychological empowerment-performance relationships are discussed. (PsycINFO Database Record (c) 2014 APA, all rights reserved). PMID:25111249

  11. Longitudinal Study on Reciprocity between Personality Traits and Parenting Stress

    ERIC Educational Resources Information Center

    Rantanen, Johanna; Tillemann, Kati; Metsäpelto, Riitta-Leena; Kokko, Katja; Pulkkinen, Lea

    2015-01-01

    Reciprocal associations between the Big Five personality traits and parenting stress--including both parents' feelings of their distress and perception of their incompetence as parents--were studied with 248 participants (49% of which were males). Longitudinal data, collected at ages 33/36, 42 and 50 years, were used. Cross-lagged path…

  12. Reciprocity Family Counseling: A Multi-Ethnic Model.

    ERIC Educational Resources Information Center

    Penrose, David M.

    The Reciprocity Family Counseling Method involves learning principles of behavior modification including selective reinforcement, behavioral contracting, self-correction, and over-correction. Selective reinforcement refers to the recognition and modification of parent/child responses and reinforcers. Parents and children are asked to identify…

  13. Magnetic-free non-reciprocity based on staggered commutation

    PubMed Central

    Reiskarimian, Negar; Krishnaswamy, Harish

    2016-01-01

    Lorentz reciprocity is a fundamental characteristic of the vast majority of electronic and photonic structures. However, non-reciprocal components such as isolators, circulators and gyrators enable new applications ranging from radio frequencies to optical frequencies, including full-duplex wireless communication and on-chip all-optical information processing. Such components today dominantly rely on the phenomenon of Faraday rotation in magneto-optic materials. However, they are typically bulky, expensive and not suitable for insertion in a conventional integrated circuit. Here we demonstrate magnetic-free linear passive non-reciprocity based on the concept of staggered commutation. Commutation is a form of parametric modulation with very high modulation ratio. We observe that staggered commutation enables time-reversal symmetry breaking within very small dimensions (λ/1,250 × λ/1,250 in our device), resulting in a miniature radio-frequency circulator that exhibits reduced implementation complexity, very low loss, strong non-reciprocity, significantly enhanced linearity and real-time reconfigurability, and is integrated in a conventional complementary metal–oxide–semiconductor integrated circuit for the first time. PMID:27079524

  14. Smear layer removal in canals shaped with reciprocating rotary systems

    PubMed Central

    Amaral, Paula; Llena, Carmen

    2013-01-01

    The aim was to assess the presence of smear layer after canal instrumentation with two reciprocating rotary systems and a continuous motion one. Thirty canals were shaped with Reciproc, WaveOne or Mtwo systems. Smear layer was assessed following a three value scale at coronal, middle and apical levels with a scanning electron microscopy. Reciproc scores: coronal third, 20% of the cases: 0, 60%: 1, 20%: 2; middle third, 10%: 0, 20%: 1, 70%:2; apical third: 2 in all cases. WaveOne scores: coronal third, 0 (40%), 1 (30%) and 2 (30%); middle third, 0 (20%), 1 (50%), 2 (30%); apical third, 0 (20%), 2 (80%) of cases. MTwo scores: coronal third 0 (50%), 1 (30%) 2 (20%); middle third 0 (20%), 1 (50%), 2 (30%); apical third, 0 (10%), 1 (10%), 2 (80%). No significant differences (p>0.05) were found between the three used systems. Key words:Endodontics, reciprocating motion files, rotary file, SEM, smear layer. PMID:24455087

  15. 47 CFR 97.107 - Reciprocal operating authority.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... SERVICES AMATEUR RADIO SERVICE Station Operation Standards § 97.107 Reciprocal operating authority. A non-citizen of the United States (“alien”) holding an amateur service authorization granted by the alien's government is authorized to be the control operator of an amateur station located at places where the...

  16. 47 CFR 97.107 - Reciprocal operating authority.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... SERVICES AMATEUR RADIO SERVICE Station Operation Standards § 97.107 Reciprocal operating authority. A non-citizen of the United States (“alien”) holding an amateur service authorization granted by the alien's government is authorized to be the control operator of an amateur station located at places where the...

  17. 47 CFR 97.107 - Reciprocal operating authority.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... SERVICES AMATEUR RADIO SERVICE Station Operation Standards § 97.107 Reciprocal operating authority. A non-citizen of the United States (“alien”) holding an amateur service authorization granted by the alien's government is authorized to be the control operator of an amateur station located at places where the...

  18. 47 CFR 97.107 - Reciprocal operating authority.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... SERVICES AMATEUR RADIO SERVICE Station Operation Standards § 97.107 Reciprocal operating authority. A non-citizen of the United States (“alien”) holding an amateur service authorization granted by the alien's government is authorized to be the control operator of an amateur station located at places where the...

  19. 47 CFR 97.107 - Reciprocal operating authority.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... SERVICES AMATEUR RADIO SERVICE Station Operation Standards § 97.107 Reciprocal operating authority. A non-citizen of the United States (“alien”) holding an amateur service authorization granted by the alien's government is authorized to be the control operator of an amateur station located at places where the...

  20. Elucidations on the Reciprocal Lattice and the Ewald Sphere

    ERIC Educational Resources Information Center

    Foadi, J.; Evans, G.

    2008-01-01

    The reciprocal lattice is derived through the Fourier transform of a generic crystal lattice, as done previously in the literature. A few key derivations are this time handled in detail, and the connection with x-ray diffraction is clearly pointed out. The Ewald sphere is subsequently thoroughly explained and a few comments on its representation…

  1. Aging, Neighborhood Attachment, and Fear of Crime: Testing Reciprocal Effects

    ERIC Educational Resources Information Center

    Oh, Joong-Hwan; Kim, Sangmoon

    2009-01-01

    This study attempts to examine the reciprocal effects between fear of crime and neighborhood attachment because aging is a critical factor in both discussions of fear of crime and neighborhood attachment (friendship, neighboring, social cohesion and trust, informal social control, and participation in neighborhood watch program). Using data from…

  2. A Study of Reciprocity in Preschool Play Groups

    ERIC Educational Resources Information Center

    Leiter, Michael P.

    1977-01-01

    Child-child interactions were observed in 2 preschools during free-play time and were recorded in terms of social initiations and responses. The degree of reciprocity in the quantity and quality of overall initiations as well as among the various initiation response dyads was analyzed. (Author/JMB)

  3. Play and Divergent Problem Solving: Evidence Supporting a Reciprocal Relationship.

    ERIC Educational Resources Information Center

    Wyver, Shirley R.; Spence, Susan H.

    1999-01-01

    Three studies examined the relationship between specific forms of preschoolers' social and pretend play and divergent/convergent problem solving. Naturalistic and experimental designs were used to provide clearer account of relationship and to challenge assumption of single direction of influence. Results support complex reciprocal causality model…

  4. Grooming reciprocity in female tibetan macaques macaca thibetana.

    PubMed

    Xia, Dongpo; Li, Jinhua; Garber, Paul A; Sun, Lixing; Zhu, Yong; Sun, Binghua

    2012-06-01

    Grooming among nonhuman primates is widespread and may represent an important service commodity that is exchanged within a biological marketplace. In this study, using focal animal sampling methods, we recorded grooming relationships among 12 adult females in a free-ranging group of Tibetan macaques (Macaca thibetana) at Huangshan, China, to determine the influence of rank and kinship on grooming relationships, and whether females act as reciprocal traders (exchange grooming received for grooming given) or interchange traders (interchange grooming for social tolerance or other commodities). The results showed that: (1) grooming given was positively correlated with grooming received; (2) kinship did not exert a significant influence on grooming reciprocity; and (3) grooming reciprocity occurred principally between individuals of adjacent rank; however, when females of different rank groomed, females tended to groom up the hierarchy (lower ranking individuals groomed higher ranking individuals more than vice versa). Our results support the contention that both grooming reciprocity and the interchange of grooming for tolerance represent important social tactics used by female Tibetan macaques.

  5. 32 CFR 148.1 - Intergency reciprocal acceptance .

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... reciprocal acceptance of security policies and procedures for approving, accrediting, and maintaining the secure posture of shared facilities will reduce aggregate costs, promote interoperability of agency security systems, preserve vitality of the U.S. industrial base, and advance national security objectives....

  6. Effects of Reciprocal Teaching Strategies on Reading Comprehension

    ERIC Educational Resources Information Center

    Choo, Tan Ooi Leng; Eng, Tan Kok; Ahmad, Norlida

    2011-01-01

    Reading Comprehension is one of the four components tested by the "MUET" (Malaysian University English Test) for Sixth-Form students in Malaysia, and school teachers are charged with the task of helping these students improve. This article discusses how "reciprocal teaching strategies" could help low-proficiency Sixth-Form students improve their…

  7. Reciprocity of Verbal Interaction of Teachers and Their Students.

    ERIC Educational Resources Information Center

    Randhawa, Bikkar S.

    This study addresses the question: Is the verbal interaction between teachers and students reciprocal? Teachers' and students' verbal behaviors were investigated using the verbal behavior classification system (CVC) in 72 seventh through ninth grade classrooms. The CVC system consists of a matrix of process and substance dimensions. Categories in…

  8. Reciprocity of Prosocial Behavior in Japanese Preschool Children

    ERIC Educational Resources Information Center

    Fujisawa, Keiko K.; Kutsukake, Nobuyuki; Hasegawa, Toshikazu

    2008-01-01

    This study investigated the reciprocity of prosocial behavior among 3- and 4-year-old Japanese preschool children during free-play time. Matrix correlation tests revealed positive correlations between the frequencies of object offering given and received within dyads and between the frequencies of helping given and received within dyads. These…

  9. Reciprocal Relationships between Job Resources, Personal Resources, and Work Engagement

    ERIC Educational Resources Information Center

    Xanthopoulou, Despoina; Bakker, Arnold B.; Demerouti, Evangelia; Schaufeli, Wilmar B.

    2009-01-01

    This study examined longitudinal relationships between job resources, personal resources, and work engagement. On the basis of Conservation of Resources theory, we hypothesized that job resources, personal resources, and work engagement are reciprocal over time. The study was conducted among 163 employees, who were followed-up over a period of 18…

  10. A reciprocal transformation for the Geng-Xue equation

    SciTech Connect

    Li, Nianhua Niu, Xiaoxing

    2014-05-15

    In this paper, we construct a reciprocal transformation for the Geng-Xue equation and show that, with help of this transformation, we relate the first negative flow of the modified Boussinesq hierarchy to the Geng-Xue equation. Furthermore, we analyze the construction of conserved quantities and present new ones.

  11. Attachment and Reciprocity in the Two-Year-Old Child.

    ERIC Educational Resources Information Center

    Marvin, Robert S., II

    This paper reported a pilot study on issues relevant to the social development of the 2-year-old child and discussed the results within the framework of the evolutionary-control-systems theory proposed by Bowlby (1958, 1969) and Ainsworth (1967, 1969). The issues examined were (1) attachment and (2) reciprocity, or the ability of the child-mother…

  12. Reciprocity between Reading and Writing: Strategic Processing as Common Ground

    ERIC Educational Resources Information Center

    Anderson, Nancy L.; Briggs, Connie

    2011-01-01

    Connecting reading and writing has important implications for all readers, but particularly for those who struggle in learning to read and write. Based on their work with children who struggle, the authors focus on reciprocal cognitive operations or strategies that draw on sources of knowledge used in both reading and writing. Their aim in this…

  13. The Reciprocal Relations between Morphological Processes and Reading

    ERIC Educational Resources Information Center

    Kruk, Richard S.; Bergman, Krista

    2013-01-01

    Reciprocal relations between emerging morphological processes and reading skills were examined in a longitudinal study tracking children from Grade 1 through Grade 3. The aim was to examine predictive relationships between productive morphological processing involving composing and decomposing of inflections and derivations, reading ability for…

  14. The reciprocal relations between morphological processes and reading.

    PubMed

    Kruk, Richard S; Bergman, Krista

    2013-01-01

    Reciprocal relations between emerging morphological processes and reading skills were examined in a longitudinal study tracking children from Grade 1 through Grade 3. The aim was to examine predictive relationships between productive morphological processing involving composing and decomposing of inflections and derivations, reading ability for pseudoword and word decoding, and word and passage reading comprehension after controlling for initial abilities in reading, morphological processing, phonological awareness, and vocabulary. Reciprocal influences were indicated by predictive relations among initial morphological processes and later reading abilities co-occurring with relationships between initial reading abilities and later morphological processes. Using multilevel modeling, decomposing and composing were found to predict emerging word decoding and word and passage comprehension but not pseudoword decoding. Reading comprehension predicted growth in decomposing. Subsequent regression analyses of model-estimated early linear growth in predictors and later linear growth in outcomes showed that early growth in morphological processes predicted later growth in word decoding and passage comprehension. Although reciprocal relations between emerging morphological processes and reading skills were observed, the different patterns on each side of the reciprocal "coin" indicated that the mechanisms underlying predictive influences are likely different but related to quality of lexical representations.

  15. Creating Reciprocal Learning Relationships across Socially-Constructed Borders.

    ERIC Educational Resources Information Center

    Skilton-Sylvester, Ellen; Erwin, Eileen K.

    2000-01-01

    Evaluated a service learning course that matched preservice teachers and older adult literacy learners and aimed to address widespread attrition in adult education programs and the need for multicultural education for preservice teachers. Data revealed two essential elements of successful, reciprocal learning relationships: connecting across…

  16. Integration of School and Community for Reciprocal Development.

    ERIC Educational Resources Information Center

    Baker, Victoria J.

    This paper examines the notion of reciprocal school-community development in Third World countries. Information on village schools in Sri Lanka and Senegal were gathered from interviews and observation. Tanzania is an example of a country that took radical steps to integrate schools within their respective communities in order to foster rural…

  17. 32 CFR 634.16 - Reciprocal state-military action.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... ENFORCEMENT AND CRIMINAL INVESTIGATIONS MOTOR VEHICLE TRAFFIC SUPERVISION Driving Privileges § 634.16... reciprocal suspension and revocation of driving privileges. See subpart D of this part for additional... the suspension/revocation of driving privileges, the receiving installation will terminate...

  18. Monkeys fail to reciprocate in an exchange task.

    PubMed

    Pelé, Marie; Thierry, Bernard; Call, Josep; Dufour, Valérie

    2010-09-01

    Exchanges form the basis of human economies. Animals too can engage in reciprocal interactions but they do not barter goods like humans, which raises the question of the abilities necessary for trading to occur. Previous studies have shown that non-human primates can exchange food with human partners. Here, we tested the ability of brown capuchin monkeys and Tonkean macaques to reciprocate in a task requiring two conspecifics to exchange tokens in order to obtain rewards from an experimenter. We recorded 56 transfers between subjects in capuchin monkeys and 10 in Tonkean macaques. All transfers were passive in both species. Capuchins preferentially picked up tokens valuable for them in the partner's compartment. They tended to manipulate the partner-valued tokens more often than the no-value ones, leading to more opportunities for these tokens to end up within reach of the partner. Despite optimal conditions where values of goods were defined and known by partners, however, none of the pairs tested engaged in short-term reciprocal interactions. These results indicate that calculated reciprocity was difficult if not impossible in the animals tested.

  19. Gamma ray detector shield

    DOEpatents

    Ohlinger, R.D.; Humphrey, H.W.

    1985-08-26

    A gamma ray detector shield comprised of a rigid, lead, cylindrical-shaped vessel having upper and lower portions with an pneumatically driven, sliding top assembly. Disposed inside the lead shield is a gamma ray scintillation crystal detector. Access to the gamma detector is through the sliding top assembly.

  20. Transcranial Electrical Neuromodulation Based on the Reciprocity Principle

    PubMed Central

    Fernández-Corazza, Mariano; Turovets, Sergei; Luu, Phan; Anderson, Erik; Tucker, Don

    2016-01-01

    A key challenge in multi-electrode transcranial electrical stimulation (TES) or transcranial direct current stimulation (tDCS) is to find a current injection pattern that delivers the necessary current density at a target and minimizes it in the rest of the head, which is mathematically modeled as an optimization problem. Such an optimization with the Least Squares (LS) or Linearly Constrained Minimum Variance (LCMV) algorithms is generally computationally expensive and requires multiple independent current sources. Based on the reciprocity principle in electroencephalography (EEG) and TES, it could be possible to find the optimal TES patterns quickly whenever the solution of the forward EEG problem is available for a brain region of interest. Here, we investigate the reciprocity principle as a guideline for finding optimal current injection patterns in TES that comply with safety constraints. We define four different trial cortical targets in a detailed seven-tissue finite element head model, and analyze the performance of the reciprocity family of TES methods in terms of electrode density, targeting error, focality, intensity, and directionality using the LS and LCMV solutions as the reference standards. It is found that the reciprocity algorithms show good performance comparable to the LCMV and LS solutions. Comparing the 128 and 256 electrode cases, we found that use of greater electrode density improves focality, directionality, and intensity parameters. The results show that reciprocity principle can be used to quickly determine optimal current injection patterns in TES and help to simplify TES protocols that are consistent with hardware and software availability and with safety constraints. PMID:27303311

  1. Transcranial Electrical Neuromodulation Based on the Reciprocity Principle.

    PubMed

    Fernández-Corazza, Mariano; Turovets, Sergei; Luu, Phan; Anderson, Erik; Tucker, Don

    2016-01-01

    A key challenge in multi-electrode transcranial electrical stimulation (TES) or transcranial direct current stimulation (tDCS) is to find a current injection pattern that delivers the necessary current density at a target and minimizes it in the rest of the head, which is mathematically modeled as an optimization problem. Such an optimization with the Least Squares (LS) or Linearly Constrained Minimum Variance (LCMV) algorithms is generally computationally expensive and requires multiple independent current sources. Based on the reciprocity principle in electroencephalography (EEG) and TES, it could be possible to find the optimal TES patterns quickly whenever the solution of the forward EEG problem is available for a brain region of interest. Here, we investigate the reciprocity principle as a guideline for finding optimal current injection patterns in TES that comply with safety constraints. We define four different trial cortical targets in a detailed seven-tissue finite element head model, and analyze the performance of the reciprocity family of TES methods in terms of electrode density, targeting error, focality, intensity, and directionality using the LS and LCMV solutions as the reference standards. It is found that the reciprocity algorithms show good performance comparable to the LCMV and LS solutions. Comparing the 128 and 256 electrode cases, we found that use of greater electrode density improves focality, directionality, and intensity parameters. The results show that reciprocity principle can be used to quickly determine optimal current injection patterns in TES and help to simplify TES protocols that are consistent with hardware and software availability and with safety constraints. PMID:27303311

  2. Transcranial Electrical Neuromodulation Based on the Reciprocity Principle.

    PubMed

    Fernández-Corazza, Mariano; Turovets, Sergei; Luu, Phan; Anderson, Erik; Tucker, Don

    2016-01-01

    A key challenge in multi-electrode transcranial electrical stimulation (TES) or transcranial direct current stimulation (tDCS) is to find a current injection pattern that delivers the necessary current density at a target and minimizes it in the rest of the head, which is mathematically modeled as an optimization problem. Such an optimization with the Least Squares (LS) or Linearly Constrained Minimum Variance (LCMV) algorithms is generally computationally expensive and requires multiple independent current sources. Based on the reciprocity principle in electroencephalography (EEG) and TES, it could be possible to find the optimal TES patterns quickly whenever the solution of the forward EEG problem is available for a brain region of interest. Here, we investigate the reciprocity principle as a guideline for finding optimal current injection patterns in TES that comply with safety constraints. We define four different trial cortical targets in a detailed seven-tissue finite element head model, and analyze the performance of the reciprocity family of TES methods in terms of electrode density, targeting error, focality, intensity, and directionality using the LS and LCMV solutions as the reference standards. It is found that the reciprocity algorithms show good performance comparable to the LCMV and LS solutions. Comparing the 128 and 256 electrode cases, we found that use of greater electrode density improves focality, directionality, and intensity parameters. The results show that reciprocity principle can be used to quickly determine optimal current injection patterns in TES and help to simplify TES protocols that are consistent with hardware and software availability and with safety constraints.

  3. Multiple reciprocal translocations in salivary gland mucoepidermoid carcinomas.

    PubMed

    Tonon, Giovanni; Gehlhaus, Kristen Stover; Yonescu, Raluca; Kaye, Frederic J; Kirsch, Ilan R

    2004-07-01

    Mucoepidermoid carcinoma, the most common human malignant salivary gland tumor, can arise from both major and minor salivary glands, including sites within the pulmonary tracheobronchial tree. We performed comparative genomic hybridization (CGH) and spectral karyotyping (SKY) on two tumor cell lines: H3118, derived from tumor originating in the parotid gland, and H292, from tumor in the lung. In both cell lines, CGH showed a partial gain within the short arm of chromosome 7 and SKY revealed the presence of the previously reported reciprocal translocation t(11;19)(q21;p12). Additional chromosomal rearrangements were found in both cell lines, including three more reciprocal translocations in cell line H292 [t(1;16), t(6;8)x2] and three other reciprocal translocations in cell line H3118 [t(1;7), t(3;15), and t(7;15)]. A review of the literature of other reported cases of mucoepidermoid carcinomas analyzed with standard G-banding techniques, as well as distinct benign salivary gland tumors, such as pleomorphic adenomas and Warthin tumor, confirmed the presence of a karyotype dominated by reciprocal translocations. Four chromosomal bands were involved in chromosomal translocations in both cell lines: 1q32, 5p15, 7q22, and 15q22. Fluorescence in situ hybridization studies showed that the breakpoints in these four bands were often within a few megabases of each other. The involvement of similar chromosomal bands in breakpoints in these two cell lines suggests that these regions may be predisposed or selected for chromosomal rearrangements in this tumor type. The presence of multiple reciprocal translocations in both benign and malignant salivary gland tumors may also suggest a particular mechanism within mucous or serous glands mediating chromosomal rearrangements.

  4. 14 CFR 121.175 - Airplanes: Reciprocating engine-powered: Weight limitations.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 3 2010-01-01 2010-01-01 false Airplanes: Reciprocating engine-powered... Performance Operating Limitations § 121.175 Airplanes: Reciprocating engine-powered: Weight limitations. (a) No person may take off a reciprocating engine powered airplane from an airport located at...

  5. 14 CFR 121.181 - Airplanes: Reciprocating engine-powered: En route limitations: One engine inoperative.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 3 2012-01-01 2012-01-01 false Airplanes: Reciprocating engine-powered: En... OPERATIONS Airplane Performance Operating Limitations § 121.181 Airplanes: Reciprocating engine-powered: En... person operating a reciprocating engine powered airplane may take off that airplane at a weight,...

  6. 14 CFR 121.181 - Airplanes: Reciprocating engine-powered: En route limitations: One engine inoperative.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 3 2011-01-01 2011-01-01 false Airplanes: Reciprocating engine-powered: En... OPERATIONS Airplane Performance Operating Limitations § 121.181 Airplanes: Reciprocating engine-powered: En... person operating a reciprocating engine powered airplane may take off that airplane at a weight,...

  7. 14 CFR 121.181 - Airplanes: Reciprocating engine-powered: En route limitations: One engine inoperative.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 3 2013-01-01 2013-01-01 false Airplanes: Reciprocating engine-powered: En... OPERATIONS Airplane Performance Operating Limitations § 121.181 Airplanes: Reciprocating engine-powered: En... person operating a reciprocating engine powered airplane may take off that airplane at a weight,...

  8. Gamma-ray and neutron spectroscopy of planetary surfaces and atmospheres

    SciTech Connect

    Reedy, R.C.

    1987-01-01

    The neutrons and gamma rays escaping from a planet can be used to map the concentrations of various elements in its surface. In a planet, the high-energy particles in the galactic cosmic rays induce a cascade of particles that includes many neutrons. The ..gamma.. rays are made by the decay of the naturally-occurring radioelements and by nuclear excitations induced by cosmic-ray particles and their secondaries (especially neutron capture or inelastic scattering reactions). After a short history of planetary ..gamma..-ray and neutron spectroscopy, the ..gamma..-ray spectrometer and active neutron detection system planned for the Mars Observer Mission are presented. The results of laboratory experiments that simulate the cosmic-ray bombardments of planetary surfaces and the status of the theoretical calculations for the processes that make and transport neutrons and ..gamma.. rays will be reviewed. Studies of Mars, including its atmosphere, are emphasized, as are new ideas, concepts, and problems that have arisen over the last decade, such as Doppler broadening and peaks from neutron scattering with germanium nuclei in a ..gamma..-ray spectrometer. 23 refs., 1 fig.

  9. The Effect of Reciprocal Peer Tutoring and Non-Reciprocal Peer Tutoring on the Performance of Students in College Physics

    ERIC Educational Resources Information Center

    Dioso-Henson, Luzale

    2012-01-01

    Formalised peer-to-peer collaboration and the use of web-enhanced materials that are consistent with course objectives, graded assessments and learning outcomes is well known in educational practice. This study compared the academic gains of college students enrolled in Physics using Reciprocal Peer Tutoring (RPT) with others using non-Reciprocal…

  10. Rehabilitation of gamma

    NASA Astrophysics Data System (ADS)

    Poynton, Charles A.

    1998-07-01

    Gamma characterizes the reproduction of tone scale in an imaging system. Gamma summarizes, in a single numerical parameter, the nonlinear relationship between code value--in an 8-bit system, from 0 through 255--and physical intensity. Nearly all image coding systems are nonlinear, and so involve values of gamma different from unity. Owing to poor understanding of tone scale reproduction, and to misconceptions about nonlinear coding, gamma has acquired a terrible reputation in computer graphics and image processing. In addition, the world-wide web suffers from poor reproduction of grayscale and color images, due to poor handling of nonlinear image coding. This paper aims to make gamma respectable again.

  11. Search for X-Ray Induced Acceleration of the Decay of the 31-yr Isomer 178Hf Using Synchrotron Radiation

    SciTech Connect

    Ahmad, I; Banar, J C; Becker, J A; Gemmell, D S; Kraemer, A; Mashayekhi, A; McNabb, D P; Miller, G G; Moore, E F; Pangault, L N; Rundberg, R S; Schiffer, J P; Shastri, S D; Wang, T F; Wilhelmy, J B

    2002-05-09

    Releasing the energy stored in an isomeric nuclear state in a controlled way with an atomic or electromagnetic trigger is an attractive speculation: the energy gain may be on the order of the ratio of nuclear/atomic energies - MeV/keV. (Nuclear isomers are loosely defined as excited nuclear states with lifetimes longer than 10{sup -9} s.) Nuclear isomers, therefore, represent an opportunity for a stand-alone energy source if suitable schemes for trigger and control of the energy release can be found. Potential applications include space drive, as well as very bright {gamma}-ray sources. The nucleus {sup 178}Hf has a nuclear isomer with excitation energy E{sub x} = 2.447 MeV. The 2.447-MeV isomeric state decays slowly (t{sub 1/2} = 31 y) to the nearby state at 2.433 MeV. The J{sup {pi}} = 13{sup -} state loses energy in a rapid (t {approx} 10{sup -12} s) {gamma}-ray cascade ending at the 8{sup -} rotational band head which in turn decays via the ground-state rotational band cascade. The {gamma}-ray cascade is delayed at the 8{sup -} state at 1.147 MeV, since the 8{sup -} state is also isomeric, with t{sub 1/2} = 4 s. Very scarce quantities of the 16{sup +}, 31-yr isomer are available for research ({approx} 10{sup 15} atoms). Reports of triggered decay of the {sup 178}Hf isomer induced by x-rays delivered by a dental x-ray machine have been made [2,3]. Enhancements of {approx} 1 - 2% in the isomer decay rate (dN/dt = - (1 + {var_epsilon})N/{tau}) had been reported for various {gamma}-rays in the cascade (distinguished by red and vertical lines in Figure 1). The reported integrated cross section for triggering the decay is cm{sup 2} keV, so large as to demand new physics. We have sought to verify these reports taking advantage of the intense photon flux available at the Advanced Photon Source.

  12. Resonance production in. gamma gamma. collisions

    SciTech Connect

    Renard, F.M.

    1983-04-01

    The processes ..gamma gamma.. ..-->.. hadrons can be depicted as follows. One photon creates a q anti q pair which starts to evolve; the other photon can either (A) make its own q anti q pair and the (q anti q q anti q) system continue to evolve or (B) interact with the quarks of the first pair and lead to a modified (q anti q) system in interaction with C = +1 quantum numbers. A review of the recent theoretical activity concerning resonance production and related problems is given under the following headings: hadronic C = +1 spectroscopy (q anti q, qq anti q anti q, q anti q g, gg, ggg bound states and mixing effects); exclusive ..gamma gamma.. processes (generalities, unitarized Born method, VDM and QCD); total cross section (soft and hard contributions); q/sup 2/ dependence of soft processes (soft/hard separation, 1/sup +- +/ resonances); and polarization effects. (WHK)

  13. Lunar elemental analysis obtained from the Apollo gamma-ray and X-ray remote sensing experiment

    NASA Technical Reports Server (NTRS)

    Trombka, J. I.; Arnold, J. R.; Adler, I.; Metzger, A. E.; Reedy, R. C.

    1974-01-01

    Gamma ray and X-ray spectrometers carried in the service module of the Apollo 15 and 16 spacecraft were employed for compositional mapping of the lunar surface. The measurements involved the observation of the intensity and characteristics energy distribution of gamma rays and X-rays emitted from the lunar surface. A large scale compositional map of over 10 percent of the lunar surface was obtained from an analysis of the observed spectra. The objective of the X-ray experiment was to measure the K spectral lines from Mg, Al, and Si. Spectra were obtained and the data were reduced to Al/Si and Mg/Si intensity ratios and ultimately to chemical ratios. The objective of the gamma-ray experiment was to measure the natural and cosmic ray induced activity emission spectrum. At this time, the elemental abundances for Th, U, K, Fe, Ti, Si, and O have been determined over a number of major lunar regions.

  14. Chaos, oscillation and the evolution of indirect reciprocity in n-person games.

    PubMed

    Suzuki, Shinsuke; Akiyama, Eizo

    2008-06-21

    Evolution of cooperation among genetically unrelated individuals has been of considerable concern in various fields such as biology, economics, and psychology. The evolution of cooperation is often explained by reciprocity. Under reciprocity, cooperation can prevail in a society because a donor of cooperation receives reciprocation from the recipient of the cooperation, called direct reciprocity, or from someone else in the community, called indirect reciprocity. Nowak and Sigmund [1993. Chaos and the evolution of cooperation. Proc. Natl. Acad. Sci. USA 90, 5091-5094] have demonstrated that directly reciprocal cooperation in two-person prisoner's dilemma games with mutation of strategies can be maintained dynamically as periodic or chaotic oscillation. Furthermore, Eriksson and Lindgren [2005. Cooperation driven by mutations in multi-person Prisoner's Dilemma. J. Theor. Biol. 232, 399-409] have reported that directly reciprocal cooperation in n-person prisoner's dilemma games (n>2) can be maintained as periodic oscillation. Is dynamic cooperation observed only in direct reciprocity? Results of this study show that indirectly reciprocal cooperation in n-person prisoner's dilemma games can be maintained dynamically as periodic or chaotic oscillation. This is, to our knowledge, the first demonstration of chaos in indirect reciprocity. Furthermore, the results show that oscillatory dynamics are observed in common in the evolution of reciprocal cooperation whether for direct or indirect.

  15. Reciprocity-based reasons for benefiting research participants: most fail, the most plausible is problematic.

    PubMed

    Sofaer, Neema

    2014-11-01

    A common reason for giving research participants post-trial access (PTA) to the trial intervention appeals to reciprocity, the principle, stated most generally, that if one person benefits a second, the second should reciprocate: benefit the first in return. Many authors consider it obvious that reciprocity supports PTA. Yet their reciprocity principles differ, with many authors apparently unaware of alternative versions. This article is the first to gather the range of reciprocity principles. It finds that: (1) most are false. (2) The most plausible principle, which is also problematic, applies only when participants experience significant net risks or burdens. (3) Seldom does reciprocity support PTA for participants or give researchers stronger reason to benefit participants than equally needy non-participants. (4) Reciprocity fails to explain the common view that it is bad when participants in a successful trial have benefited from the trial intervention but lack PTA to it.

  16. Reciprocity-Based Reasons for Benefiting Research Participants: Most Fail, the Most Plausible is Problematic

    PubMed Central

    Sofaer, Neema

    2014-01-01

    A common reason for giving research participants post-trial access (PTA) to the trial intervention appeals to reciprocity, the principle, stated most generally, that if one person benefits a second, the second should reciprocate: benefit the first in return. Many authors consider it obvious that reciprocity supports PTA. Yet their reciprocity principles differ, with many authors apparently unaware of alternative versions. This article is the first to gather the range of reciprocity principles. It finds that: (1) most are false. (2) The most plausible principle, which is also problematic, applies only when participants experience significant net risks or burdens. (3) Seldom does reciprocity support PTA for participants or give researchers stronger reason to benefit participants than equally needy non-participants. (4) Reciprocity fails to explain the common view that it is bad when participants in a successful trial have benefited from the trial intervention but lack PTA to it. PMID:24602060

  17. Experience sharing, emotional reciprocity, and turn-taking

    PubMed Central

    Stevanovic, Melisa; Peräkylä, Anssi

    2015-01-01

    In this perspective article, we consider the relationship between experience sharing and turn-taking. There is much evidence suggesting that human social interaction is permeated by two temporal organizations: (1) the sequential framework of turn-taking and (2) the concurrent framework of emotional reciprocity. From this perspective, we introduce two alternative hypotheses about how the relationship between experience sharing and turn-taking could be viewed. According to the first hypothesis, the home environment of experience sharing is in the concurrent framework of emotional reciprocity, while the motivation to share experiences is in tension with the sequential framework of turn-taking. According to the second hypothesis, people’s inclination to coordinate their actions in terms of turn-taking is motivated precisely by their propensity to share experiences. We consider theoretical and empirical ideas in favor of both of these hypotheses and discuss their implications for future research. PMID:25926811

  18. A dual reciprocal boundary element formulation for viscous flows

    NASA Technical Reports Server (NTRS)

    Lafe, Olu

    1993-01-01

    The advantages inherent in the boundary element method (BEM) for potential flows are exploited to solve viscous flow problems. The trick is the introduction of a so-called dual reciprocal technique in which the convective terms are represented by a global function whose unknown coefficients are determined by collocation. The approach, which is necessarily iterative, converts the governing partial differential equations into integral equations via the distribution of fictitious sources or dipoles of unknown strength on the boundary. These integral equations consist of two parts. The first is a boundary integral term, whose kernel is the unknown strength of the fictitious sources and the fundamental solution of a convection-free flow problem. The second part is a domain integral term whose kernel is the convective portion of the governing PDEs. The domain integration can be transformed to the boundary by using the dual reciprocal (DR) concept. The resulting formulation is a pure boundary integral computational process.

  19. An experimental study of strong reciprocity in bacteria.

    PubMed

    Inglis, R Fredrik; West, Stuart; Buckling, Angus

    2014-02-01

    Strong reciprocity, whereby cooperators punish non-cooperators, may help to explain the evolutionary success of cooperative behaviours. However, theory suggests that selection for strong reciprocity can depend upon tight genetic linkage between cooperation and punishment, to avoid the strategy being outcompeted by non-punishing cooperators. We tested this hypothesis using experimental populations of the bacterium Pseudomonas aeruginosa, which cooperate by producing iron-scavenging siderophores and, in this context, punish non-cooperators with toxins. Consistent with theory, we show that cooperative punishers can indeed invade cheats, but only when the traits are tightly linked. These results emphasize that punishment is only likely to be favoured when the punishment itself leads to a direct or indirect fitness benefit to the actor.

  20. Paying it forward: generalized reciprocity and the limits of generosity.

    PubMed

    Gray, Kurt; Ward, Adrian F; Norton, Michael I

    2014-02-01

    When people are the victims of greed or recipients of generosity, their first impulse is often to pay back that behavior in kind. What happens when people cannot reciprocate, but instead have the chance to be cruel or kind to someone entirely different--to pay it forward? In 5 experiments, participants received greedy, equal, or generous divisions of money or labor from an anonymous person and then divided additional resources with a new anonymous person. While equal treatment was paid forward in kind, greed was paid forward more than generosity. This asymmetry was driven by negative affect, such that a positive affect intervention disrupted the tendency to pay greed forward. Implications for models of generalized reciprocity are discussed.

  1. Ubiquity of Benford's law and emergence of the reciprocal distribution

    DOE PAGES

    Friar, James Lewis; Goldman, Terrance J.; Pérez-Mercader, J.

    2016-04-07

    In this paper, we apply the Law of Total Probability to the construction of scale-invariant probability distribution functions (pdf's), and require that probability measures be dimensionless and unitless under a continuous change of scales. If the scale-change distribution function is scale invariant then the constructed distribution will also be scale invariant. Repeated application of this construction on an arbitrary set of (normalizable) pdf's results again in scale-invariant distributions. The invariant function of this procedure is given uniquely by the reciprocal distribution, suggesting a kind of universality. Finally, we separately demonstrate that the reciprocal distribution results uniquely from requiring maximum entropymore » for size-class distributions with uniform bin sizes.« less

  2. The valve motion characteristics of a reciprocating pump

    NASA Astrophysics Data System (ADS)

    Pei, Junfeng; He, Chao; Lv, Miaorong; Huang, Xianru; Shen, Kejun; Bi, Kunlei

    2016-01-01

    In previous studies on a reciprocating pump, the state, behavior simulation, or experimental analysis of the valve was seldom reported. In the paper, taking a triplex single-acting reciprocating pump as the research object, we established an experimental system for testing valve disc's motion parameters to directly acquire the valve disc motion parameters (acceleration, velocity, and displacement) under actual conditions. Moreover, testing results were compared with the calculation results obtained according to U. Adolph Theory and Approximation Theory. In Approximation Theory, the valve disc motion was not fully considered, thus leading to the large deviation from the actual situation. Compared with the Approximation Theory, U. Adolph Theory is more suitable for the determination of valve disc motion parameters during different strokes and can explain the jumping and hysteresis phenomena of the valve well. A new pump testing method and an experimental system were proposed to provide a new study approach for valve design theory, disc damage mechanism, and pump failure diagnosis.

  3. Reciprocal teaching of social studies in inclusive elementary classrooms.

    PubMed

    Lederer, J M

    2000-01-01

    Reading comprehension relies on the use of metacognitive strategies. Reciprocal teaching has been found to be an effective comprehension technique to use with students with learning disabilities. This study examined the effectiveness of reciprocal teaching during social studies instruction with several students with learning disabilities in fourth-, fifth-, and sixth-grade inclusive classrooms. One hundred and twenty-eight students in Grades 4, 5, and 6 participated. Four comprehension assessments were administered, as well as an external measure and 30-day maintenance assessment. A mixed-design MANOVA was used to determine interaction on three reading comprehension measures. Results indicated that all students improved their performance on comprehension measures compared with students in the control groups. Improvement continued to be displayed after 30 days in both the sixth and the fourth grades. Students with learning disabilities significantly improved their ability to compose summaries compared to the control students.

  4. Non-reciprocal and highly nonlinear active acoustic metamaterials

    NASA Astrophysics Data System (ADS)

    Popa, Bogdan-Ioan; Cummer, Steven A.

    2014-02-01

    Unidirectional devices that pass acoustic energy in only one direction have numerous applications and, consequently, have recently received significant attention. However, for most practical applications that require unidirectionality at audio and low frequencies, subwavelength implementations capable of the necessary time-reversal symmetry breaking remain elusive. Here we describe a design approach based on metamaterial techniques that provides highly subwavelength and strongly non-reciprocal devices. We demonstrate this approach by designing and experimentally characterizing a non-reciprocal active acoustic metamaterial unit cell composed of a single piezoelectric membrane augmented by a nonlinear electronic circuit, and sandwiched between Helmholtz cavities tuned to different frequencies. The design is thinner than a tenth of a wavelength, yet it has an isolation factor of >10 dB. The design method generates relatively broadband unidirectional devices and is a good candidate for numerous acoustic applications.

  5. Non-reciprocal and highly nonlinear active acoustic metamaterials.

    PubMed

    Popa, Bogdan-Ioan; Cummer, Steven A

    2014-01-01

    Unidirectional devices that pass acoustic energy in only one direction have numerous applications and, consequently, have recently received significant attention. However, for most practical applications that require unidirectionality at audio and low frequencies, subwavelength implementations capable of the necessary time-reversal symmetry breaking remain elusive. Here we describe a design approach based on metamaterial techniques that provides highly subwavelength and strongly non-reciprocal devices. We demonstrate this approach by designing and experimentally characterizing a non-reciprocal active acoustic metamaterial unit cell composed of a single piezoelectric membrane augmented by a nonlinear electronic circuit, and sandwiched between Helmholtz cavities tuned to different frequencies. The design is thinner than a tenth of a wavelength, yet it has an isolation factor of >10 dB. The design method generates relatively broadband unidirectional devices and is a good candidate for numerous acoustic applications. PMID:24572771

  6. Construction and analysis of 2 reciprocal Arabidopsis introgression line populations.

    PubMed

    Törjék, Ottó; Meyer, Rhonda C; Zehnsdorf, Maik; Teltow, Melanie; Strompen, Georg; Witucka-Wall, Hanna; Blacha, Anna; Altmann, Thomas

    2008-01-01

    Two new large reciprocal sets of introgression lines (ILs) were created between the Arabidopsis accessions Col-0 and C24. In both sets (78 ILs with Col-0 background and 62 ILs with C24 background), the donor segments cover almost the entire genome with an average substitution size of 18.3 cM. In addition to the basic sets of ILs, further subILs were developed for 2 genomic regions allowing better mapping resolution. SubILs carrying donor segments with candidate genes for flowering time and reduced fertility were used to demonstrate the usefulness of the reciprocal ILs for quantitative trait loci detection and fine mapping. For subIL development at high resolution around the reduced fertility locus, we used modified CelI-based assays in one-well format for both marker development and genotyping. This serves as a very flexible and cost-effective approach.

  7. Diminishing reciprocal fairness by disrupting the right prefrontal cortex.

    PubMed

    Knoch, Daria; Pascual-Leone, Alvaro; Meyer, Kaspar; Treyer, Valerie; Fehr, Ernst

    2006-11-01

    Humans restrain self-interest with moral and social values. They are the only species known to exhibit reciprocal fairness, which implies the punishment of other individuals' unfair behaviors, even if it hurts the punisher's economic self-interest. Reciprocal fairness has been demonstrated in the Ultimatum Game, where players often reject their bargaining partner's unfair offers. Despite progress in recent years, however, little is known about how the human brain limits the impact of selfish motives and implements fair behavior. Here we show that disruption of the right, but not the left, dorsolateral prefrontal cortex (DLPFC) by low-frequency repetitive transcranial magnetic stimulation substantially reduces subjects' willingness to reject their partners' intentionally unfair offers, which suggests that subjects are less able to resist the economic temptation to accept these offers. Importantly, however, subjects still judge such offers as very unfair, which indicates that the right DLPFC plays a key role in the implementation of fairness-related behaviors.

  8. Dynamic study of piping systems for reciprocating compressors

    SciTech Connect

    Wakabayashi, A.; Arai, S.; Yamada, S.

    1995-12-01

    Recently the authors have developed the direct method to study vibration of piping systems for reciprocating compressors, based on the requirement by API-618 Design Approach-3. They have examined the reliability of this direct method by some experiments with a test piping system, by pressure pulsation and nodal vibration measurements. Overall pressure pulsation amplitude and its frequency components at each measurement point were proved.to agree with the results by digital analysis. Close evaluation of ``pipe-supports` stiffness``, as well as boundary conditions, was confirmed to be a necessary condition to proceed the dynamic analysis of the piping system in relation to the pressure pulsation Generated by the reciprocating compressor, which affected the accuracy of final estimation of nodal displacement distribution of the piping system. Field data evaluation is also discussed in this paper.

  9. Reciprocal subsidies: dynamic interdependence between terrestrial and aquatic food webs.

    PubMed

    Nakano, S; Murakami, M

    2001-01-01

    Mutual trophic interactions between contiguous habitats have remained poorly understood despite their potential significance for community maintenance in ecological landscapes. In a deciduous forest and stream ecotone, aquatic insect emergence peaked around spring, when terrestrial invertebrate biomass was low. In contrast, terrestrial invertebrate input to the stream occurred primarily during summer, when aquatic invertebrate biomass was nearly at its lowest. Such reciprocal, across-habitat prey flux alternately subsidized both forest birds and stream fishes, accounting for 25.6% and 44.0% of the annual total energy budget of the bird and fish assemblages, respectively. Seasonal contrasts between allochthonous prey supply and in situ prey biomass determine the importance of reciprocal subsidies.

  10. Fault detection in reciprocating compressor valves under varying load conditions

    NASA Astrophysics Data System (ADS)

    Pichler, Kurt; Lughofer, Edwin; Pichler, Markus; Buchegger, Thomas; Klement, Erich Peter; Huschenbett, Matthias

    2016-03-01

    This paper presents a novel approach for detecting cracked or broken reciprocating compressor valves under varying load conditions. The main idea is that the time frequency representation of vibration measurement data will show typical patterns depending on the fault state. The problem is to detect these patterns reliably. For the detection task, we make a detour via the two dimensional autocorrelation. The autocorrelation emphasizes the patterns and reduces noise effects. This makes it easier to define appropriate features. After feature extraction, classification is done using logistic regression and support vector machines. The method's performance is validated by analyzing real world measurement data. The results will show a very high detection accuracy while keeping the false alarm rates at a very low level for different compressor loads, thus achieving a load-independent method. The proposed approach is, to our best knowledge, the first automated method for reciprocating compressor valve fault detection that can handle varying load conditions.

  11. Analysis of mutant quantity and quality in human-hamster hybrid AL and AL-179 cells exposed to 137Cs-gamma or HZE-Fe ions

    NASA Technical Reports Server (NTRS)

    Waldren, C.; Vannais, D.; Drabek, R.; Gustafson, D.; Kraemer, S.; Lenarczyk, M.; Kronenberg, A.; Hei, T.; Ueno, A.; Chatterjee, A. (Principal Investigator)

    1998-01-01

    We measured the number of mutants and the kinds of mutations induced by 137Cs-gamma and by HZE-Fe (56Fe [600 MeV/amu, LET = 190 KeV/micrometer) in standard AL human hamster hybrid cells and in a new variant hybrid, AL-179. We found that HZE-Fe was more mutagenic than 137Cs-gamma per unit dose (about 1.6 fold), but was slightly less mutagenic per mean lethal dose, DO, at both the S1 and hprt- loci of AL cells. On the other hand, HZE-Fe induced about nine fold more complex S1- mutants than 137Cs-gamma rays, 28% vs 3%. 137Cs-gamma rays induced about twice as many S1- mutants and hprt-mutants in AL-179 as in AL cells, and about nine times more of the former were complex, and potentially unstable kinds of mutations.

  12. Emerging Signs of Strong Reciprocity in Human Ontogeny

    PubMed Central

    Robbins, Erin; Rochat, Philippe

    2011-01-01

    Strong reciprocity is considered here as the propensity to sacrifice resources to be kind or to punish in response to prior acts, a behavior not simply reducible to self-interest and a likely force behind human cooperation and sociality. The aim was to capture emerging signs of strong reciprocity in human ontogeny and across highly contrasted cultures. Three- and 5-year-old middle class American children (N = 162) were tested in a simple, multiple round, three-way sharing game involving the child, a generous puppet, and a stingy puppet. At the end of the game, the child was offered an opportunity to sacrifice some of her personal gains to punish one of the puppets. By 3 years, American children demonstrate a willingness to engage in costly punishment. However, only 5-year-olds show some evidence of strong reciprocity by orienting their punishment systematically toward the stingy puppet. Further analyses and three additional control conditions demonstrate that such propensity is not simply reducible to (a) straight imitation, or (b) inequity aversion. To assess the relative universality of such development, a group of 5- to 6-year-old children from rural Samoa (N = 14) were tested and compared to age and gender-matched American children. Samoan children did not manifest the same propensity toward strong reciprocity. The results are interpreted as pointing to (1) the developmental emergence of an ethical stance between 3 and 5 years of age, and (2) that the expression of such stance by young children could depend on culture. PMID:22194730

  13. Degree and reciprocity of self-disclosure in online forums.

    PubMed

    Barak, Azy; Gluck-Ofri, Orit

    2007-06-01

    Cyberspace has become a common social environment in which people interact and operate in many ways. The purpose of the present study was to investigate the occurrence and reciprocity of self-disclosure, two subjects that are extensively studied in face-to-face interactions but only to a limited degree in virtual, computer-mediated, textual communication. Data was based on 240 first messages in a thread, sampled in equal numbers from six Internet forums (three discussion and three support groups), and written in equal numbers by each gender, and 240 first responses to them (a total of 480 forum messages). Trained, expert judges blindly rated each message on the degree to which it disclosed personal information, thoughts, and feelings. Linguistic parameters (total number of words and number of first-voice words) were also used as dependent variables. Results showed the following: (a) self-disclosure in support forums was much higher than in discussion forums, in terms of both total number and type of disclosure; (b) messages in support forums were longer and included more first-voice words than in discussion forums; (c) there were no gender differences interacting with level of self-disclosure; (d) reciprocity of self-disclosure was evident, yielding positive correlations between the measures of self-disclosure in messages and responses to them; (e) some differences appeared in level of reciprocity of self-disclosure between male and female participants, with female respondents tending to be more reciprocal than male respondents. The implications of these results are discussed in light of growing social interactions online, and possible applications are suggested. PMID:17594265

  14. Reciprocity theorem and perturbation theory for photonic crystal waveguides.

    PubMed

    Michaelis, D; Peschel, U; Wächter, C; Bräuer, A

    2003-12-01

    Starting from Maxwell's equations we derive a reciprocity theorem for photonic crystal waveguides. A set of strongly coupled discrete equations results, which can be applied to the simulation of perturbed photonic crystal waveguides. As an example we analytically study the influence of the dispersion of a two level system on the band structure of a photonic crystal waveguide. In particular, the formation of polariton gaps is discussed.

  15. Self-Centering Reciprocating-Permanent-Magnet Machine

    NASA Technical Reports Server (NTRS)

    Bhate, Suresh; Vitale, Nick

    1988-01-01

    New design for monocoil reciprocating-permanent-magnet electric machine provides self-centering force. Linear permanent-magnet electrical motor includes outer stator, inner stator, and permanent-magnet plunger oscillateing axially between extreme left and right positions. Magnets arranged to produce centering force and allows use of only one coil of arbitrary axial length. Axial length of coil chosen to provide required efficiency and power output.

  16. Evidence of Broken Reciprocity in Cholesteric Liquid Crystals

    NASA Astrophysics Data System (ADS)

    Venkataraman, Nithya; Moreira, Michele; Taheri, Bahman; Palffy-Muhoray, Peter

    2007-03-01

    Reciprocity of scattering of a plane incident wave is predicated on bounded scattering media with symmetric and linear permittivity, conductivity and permeability. In chiral media, such as cholesteric liquid crystals, the dielectric tensor is asymmetric due the presence of odd powers of the wave vector resulting from nonlocality and broken inversion symmetry. Evidence of non-reciprocity has been found in optically active crystals by Bennet [1] and in stacks of cholesteric and nematic liquid crystal cells [2]. Here we present transmittance and reflectance data for cholesteric cells with different pitches having overlapping but distinct reflection bands. We relate our results to simple analytic descriptions of the materials properties and of propagating modes and assess them in light of the requirements for reciprocity. 1. P.J. Bennett, S. Dhanjal, Yu. P. Svirko and N. I. Zheludev, Opt. Lett. 21, 1955 (1996) 2. J. Hwang; M.H. Song; B. Park; S. Nishimura; T. Toyooka; J.W. Wu; Y. Takanishi; K. Ishikawa; H. Takezoe, Nat. Mat. 4, 383 (2005).

  17. Evidence of Broken Reciprocity in Chiral Liquid Crystals

    NASA Astrophysics Data System (ADS)

    Moreira, Michele; Venkataraman, Nithya; Taheri, Bahman; Palffy-Muhoray, Peter

    2008-03-01

    Reciprocity in light scattering is predicated on bounded scattering media with symmetric and linear permittivity, conductivity and permeability. Due to their anisotropy and chirality, cholesteric liquid crystal form periodic dielectric structures. If the periodicity is comparable to the wavelength of light, these phases are self-assembled photonic band gap structures. There appear in the permittivity odd powers of the wave vector resulting from nonlocality and broken inversion symmetry. Evidence of non-reciprocity has been found in optically active crystals by Bennett [1] and in stacks of cholesteric and nematic liquid crystal cells by Takezoe [2]. We present experimental data showing broken reciprocity in transmittance and reflectance in cholesteric cells with different pitches having overlapping but distinct reflection bands. We explain our results in terms of simple analytic descriptions of material properties and propagating modes. [1] P.J. Bennett, S. Dhanjal, Yu. P. Svirko and N. I. Zheludev, Opt. Lett. 21, 1955 (1996) [2] J. Hwang; M.H. Song; B. Park; S. Nishimura; T. Toyooka; J.W. Wu; Y. Takanishi; K. Ishikawa; H. Takezoe, Nat. Mat. 4, 383 (2005).

  18. The evolution of strong reciprocity: cooperation in heterogeneous populations.

    PubMed

    Bowles, Samuel; Gintis, Herbert

    2004-02-01

    How do human groups maintain a high level of cooperation despite a low level of genetic relatedness among group members? We suggest that many humans have a predisposition to punish those who violate group-beneficial norms, even when this imposes a fitness cost on the punisher. Such altruistic punishment is widely observed to sustain high levels of cooperation in behavioral experiments and in natural settings. We offer a model of cooperation and punishment that we call STRONG RECIPROCITY: where members of a group benefit from mutual adherence to a social norm, strong reciprocators obey the norm and punish its violators, even though as a result they receive lower payoffs than other group members, such as selfish agents who violate the norm and do not punish, and pure cooperators who adhere to the norm but free-ride by never punishing. Our agent-based simulations show that, under assumptions approximating likely human environments over the 100000 years prior to the domestication of animals and plants, the proliferation of strong reciprocators when initially rare is highly likely, and that substantial frequencies of all three behavioral types can be sustained in a population. As a result, high levels of cooperation are sustained. Our results do not require that group members be related or that group extinctions occur. PMID:14642341

  19. Swimming by reciprocal motion at low Reynolds number.

    PubMed

    Qiu, Tian; Lee, Tung-Chun; Mark, Andrew G; Morozov, Konstantin I; Münster, Raphael; Mierka, Otto; Turek, Stefan; Leshansky, Alexander M; Fischer, Peer

    2014-11-04

    Biological microorganisms swim with flagella and cilia that execute nonreciprocal motions for low Reynolds number (Re) propulsion in viscous fluids. This symmetry requirement is a consequence of Purcell's scallop theorem, which complicates the actuation scheme needed by microswimmers. However, most biomedically important fluids are non-Newtonian where the scallop theorem no longer holds. It should therefore be possible to realize a microswimmer that moves with reciprocal periodic body-shape changes in non-Newtonian fluids. Here we report a symmetric 'micro-scallop', a single-hinge microswimmer that can propel in shear thickening and shear thinning (non-Newtonian) fluids by reciprocal motion at low Re. Excellent agreement between our measurements and both numerical and analytical theoretical predictions indicates that the net propulsion is caused by modulation of the fluid viscosity upon varying the shear rate. This reciprocal swimming mechanism opens new possibilities in designing biomedical microdevices that can propel by a simple actuation scheme in non-Newtonian biological fluids.

  20. Swimming by reciprocal motion at low Reynolds number

    PubMed Central

    Qiu, Tian; Lee, Tung-Chun; Mark, Andrew G.; Morozov, Konstantin I.; Münster, Raphael; Mierka, Otto; Turek, Stefan; Leshansky, Alexander M.; Fischer, Peer

    2014-01-01

    Biological microorganisms swim with flagella and cilia that execute nonreciprocal motions for low Reynolds number (Re) propulsion in viscous fluids. This symmetry requirement is a consequence of Purcell’s scallop theorem, which complicates the actuation scheme needed by microswimmers. However, most biomedically important fluids are non-Newtonian where the scallop theorem no longer holds. It should therefore be possible to realize a microswimmer that moves with reciprocal periodic body-shape changes in non-Newtonian fluids. Here we report a symmetric ‘micro-scallop’, a single-hinge microswimmer that can propel in shear thickening and shear thinning (non-Newtonian) fluids by reciprocal motion at low Re. Excellent agreement between our measurements and both numerical and analytical theoretical predictions indicates that the net propulsion is caused by modulation of the fluid viscosity upon varying the shear rate. This reciprocal swimming mechanism opens new possibilities in designing biomedical microdevices that can propel by a simple actuation scheme in non-Newtonian biological fluids. PMID:25369018

  1. Reciprocal Space Mapping of Macromolecular Crystals in the Laboratory

    NASA Technical Reports Server (NTRS)

    Snell, Edward H.; Boggon, T. J.; Fewster, P. F.; Siddons, D. P.; Stojanof, V.; Pusey, M. L.

    1998-01-01

    The technique of reciprocal space mapping applied to the physical measurement of macromolecular crystals will be described. This technique uses a triple axis diffractometer setup whereby the monochromator is the first crystal, the sample is the second and the third crystal (of the same material as the monochromator) analyzes the diffracted beam. The geometry is such that it is possible to separate mosaic volume effects from lattice strain effects. The deconvolution of the instrument parameters will also be addressed. Results from measurements at Brookhaven National Synchrotron Radiation Source carried out on microgravity and ground-grown crystals will be presented. The required beam characteristics for reciprocal space mapping are also ideal for topographic studies and the first topographs ever recorded from microgravity protein crystal samples will be shown. We are now working on a system which will enable reciprocal space mapping, mosaicity and topography studies to be carried out in the home laboratory. This system uses a rotating anode X-ray source to provide an intense beam then a Bartels double crystal, four reflection monochromator to provide the spectral and geometric beam conditioning necessary such that the instrument characteristics do not mask the measurement. This is coupled to a high precision diffractometer and sensitive detector. Commissioning data and first results from the system will be presented.

  2. Grooming reciprocation among female primates: a meta-analysis.

    PubMed

    Schino, Gabriele; Aureli, Filippo

    2008-02-23

    The theory of reciprocal altruism offers an explanation for the evolution of altruistic behaviours among unrelated animals. Among primates, grooming is one of the most common altruistic behaviours. Primates have been suggested to exchange grooming both for itself and for rank-related benefits. While previous meta-analyses have shown that they direct their grooming up the hierarchy and exchange it for agonistic support, no comprehensive evaluation of grooming reciprocation has been made. Here we report on a meta-analysis of grooming reciprocation among female primates based on 48 social groups belonging to 22 different species and 12 genera. The results of this meta-analysis showed that female primates groom preferentially those group mates that groom them most. To the extent allowed by the availability of kinship data, this result holds true when controlling for maternal kinship. These results, together with previous findings, suggest that primates are indeed able to exchange grooming both for itself and for different rank-related benefits.

  3. Partner Choice Drives the Evolution of Cooperation via Indirect Reciprocity

    PubMed Central

    Roberts, Gilbert

    2015-01-01

    Indirect reciprocity potentially provides an important means for generating cooperation based on helping those who help others. However, the use of ‘image scores’ to summarize individuals’ past behaviour presents a dilemma: individuals withholding help from those of low image score harm their own reputation, yet giving to defectors erodes cooperation. Explaining how indirect reciprocity could evolve has therefore remained problematic. In all previous treatments of indirect reciprocity, individuals are assigned potential recipients and decide whether to cooperate or defect based on their reputation. A second way of achieving discrimination is through partner choice, which should enable individuals to avoid defectors. Here, I develop a model in which individuals choose to donate to anyone within their group, or to none. Whereas image scoring with random pairing produces cycles of cooperation and defection, with partner choice there is almost maximal cooperation. In contrast to image scoring with random pairing, partner choice results in almost perfect contingency, producing the correlation between giving and receiving required for cooperation. In this way, partner choice facilitates much higher and more stable levels of cooperation through image scoring than previously reported and provides a simple mechanism through which systems of helping those who help others can work. PMID:26057241

  4. Reciprocity principle for scattered fields from discontinuities in waveguides.

    PubMed

    Pau, Annamaria; Capecchi, Danilo; Vestroni, Fabrizio

    2015-01-01

    This study investigates the scattering of guided waves from a discontinuity exploiting the principle of reciprocity in elastodynamics, written in a form that applies to waveguides. The coefficients of reflection and transmission for an arbitrary mode can be derived as long as the principle of reciprocity is satisfied at the discontinuity. Two elastodynamic states are related by the reciprocity. One is the response of the waveguide in the presence of the discontinuity, with the scattered fields expressed as a superposition of wave modes. The other state is the response of the waveguide in the absence of the discontinuity oscillating according to an arbitrary mode. The semi-analytical finite element method is applied to derive the needed dispersion relation and wave mode shapes. An application to a solid cylinder with a symmetric double change of cross-section is presented. This model is assumed to be representative of a damaged rod. The coefficients of reflection and transmission of longitudinal waves are investigated for selected values of notch length and varying depth.

  5. Long-latency reflexes of elbow and shoulder muscles suggest reciprocal excitation of flexors, reciprocal excitation of extensors, and reciprocal inhibition between flexors and extensors.

    PubMed

    Kurtzer, Isaac; Meriggi, Jenna; Parikh, Nidhi; Saad, Kenneth

    2016-04-01

    Postural corrections of the upper limb are required in tasks ranging from handling an umbrella in the changing wind to securing a wriggling baby. One complication in this process is the mechanical interaction between the different segments of the arm where torque applied at one joint induces motion at multiple joints. Previous studies have shown the long-latency reflexes of shoulder muscles (50-100 ms after a limb perturbation) account for these mechanical interactions by integrating information about motion of both the shoulder and elbow. It is less clear whether long-latency reflexes of elbow muscles exhibit a similar capability and what is the relation between the responses of shoulder and elbow muscles. The present study utilized joint-based loads tailored to the subjects' arm dynamics to induce well-controlled displacements of their shoulder and elbow. Our results demonstrate that the long-latency reflexes of shoulder and elbow muscles integrate motion from both joints: the shoulder and elbow flexors respond to extension at both joints, whereas the shoulder and elbow extensors respond to flexion at both joints. This general pattern accounts for the inherent flexion-extension coupling of the two joints arising from the arm's intersegmental dynamics and is consistent with spindle-based reciprocal excitation of shoulder and elbow flexors, reciprocal excitation of shoulder and elbow extensors, and across-joint inhibition between the flexors and extensors.

  6. Gamma ray transients

    NASA Technical Reports Server (NTRS)

    Cline, Thomas L.

    1987-01-01

    The discovery of cosmic gamma ray bursts was made with systems designed at Los Alamos Laboratory for the detection of nuclear explosions beyond the atmosphere. HELIOS-2 was the first gamma ray burst instrument launched; its initial results in 1976, seemed to deepen the mystery around gamma ray transients. Interplanetary spacecraft data were reviewed in terms of explaining the behavior and source of the transients.

  7. {gamma} production at CDF

    SciTech Connect

    Abe, F.

    1995-07-01

    We report on preliminary measurements of the {gamma}(1S), {gamma}(2S) and {gamma}(3S) differential and integrated cross sections in p{bar p} at {radical}s = 1.8 TeV using a sample of 16.6 {+-} 0.6 pb{sup -1} collected by the Collider Detector at Fermilab. The three resonances were reconstructed through the decay {gamma} {yields} {mu}{sup +}{mu}{sup -} in the rapidity region {vert_bar}y{vert_bar} < 0.4. The cross section results are compared to theoretical models of direct bottomonium production.

  8. Gamma Oscillation in Schizophrenia

    PubMed Central

    O'Donnell, Brian F.; Youn, Soyoung; Kwon, Jun Soo

    2011-01-01

    Dysfunctional neural circuitry has been found to be involved in abnormalities of perception and cognition in patients with schizophrenia. Gamma oscillations are essential for integrating information within neural circuits and have therefore been associated with many perceptual and cognitive processes in healthy human subjects and animals. This review presents an overview of the neural basis of gamma oscillations and the abnormalities in the GABAergic interneuronal system thought to be responsible for gamma-range deficits in schizophrenia. We also review studies of gamma activity in sensory and cognitive processes, including auditory steady state response, attention, object representation, and working memory, in animals, healthy humans and patients with schizophrenia. PMID:22216037

  9. Gamma-Ray Bursts

    SciTech Connect

    Paciesas, W.S. ); Fishman, G.J. )

    1992-01-01

    This proceedings represents the works presented at the Gamma-Ray Bursts Workshop -- 1991 which was held on the campus of theUniversity of Alabama in Huntsville, October 16-18. The emphasis ofthe Workshop was to present and discuss new observations of gamma-ray bursts made recently by experiments on the Compton Gamma-RayObservatory (CGRO), Granat, Ginga, Pioneer Venus Orbiter, Prognozand Phobos. These presentations were complemented by some groundbased observations, reanalysis of older data, descriptions offuture gamma-ray burst experiments and a wide-ranging list oftheoretical discussions. Over seventy papers are included in theproceedings. Eleven of them are abstracted for the database. (AIP)

  10. Insights into the mechanism of X-ray-induced disulfide-bond cleavage in lysozyme crystals based on EPR, optical absorption and X-ray diffraction studies

    SciTech Connect

    Sutton, Kristin A.; Black, Paul J.; Mercer, Kermit R.; Garman, Elspeth F.; Owen, Robin L.; Snell, Edward H.; Bernhard, William A.

    2013-12-01

    Electron paramagnetic resonance (EPR) and online UV–visible absorption microspectrophotometry with X-ray crystallography have been used in a complementary manner to follow X-ray-induced disulfide-bond cleavage, to confirm a multi-track radiation-damage process and to develop a model of that process. Electron paramagnetic resonance (EPR) and online UV–visible absorption microspectrophotometry with X-ray crystallography have been used in a complementary manner to follow X-ray-induced disulfide-bond cleavage. Online UV–visible spectroscopy showed that upon X-irradiation, disulfide radicalization appeared to saturate at an absorbed dose of approximately 0.5–0.8 MGy, in contrast to the saturating dose of ∼0.2 MGy observed using EPR at much lower dose rates. The observations suggest that a multi-track model involving product formation owing to the interaction of two separate tracks is a valid model for radiation damage in protein crystals. The saturation levels are remarkably consistent given the widely different experimental parameters and the range of total absorbed doses studied. The results indicate that even at the lowest doses used for structural investigations disulfide bonds are already radicalized. Multi-track considerations offer the first step in a comprehensive model of radiation damage that could potentially lead to a combined computational and experimental approach to identifying when damage is likely to be present, to quantitate it and to provide the ability to recover the native unperturbed structure.

  11. Directional gamma detector

    DOEpatents

    LeVert, Francis E.; Cox, Samson A.

    1981-01-01

    An improved directional gamma radiation detector has a collector sandwiched etween two layers of insulation of varying thicknesses. The collector and insulation layers are contained within an evacuated casing, or emitter, which releases electrons upon exposure to gamma radiation. Delayed electrons and electrons entering the collector at oblique angles are attenuated as they pass through the insulation layers on route to the collector.

  12. Gamma-ray Bursts

    NASA Astrophysics Data System (ADS)

    Kouveliotou, Chryssa; Wijers, Ralph A. M. J.; Woosley, Stan

    2012-11-01

    Prologue C. Kouveliotou, R. A . M. J. Wijers and S. E. Woosley; 1. The discovery of the gamma-ray burst phenomenon R. W. Klebesadel; 2. Instrumental principles E. E. Fenimore; 3. The BATSE era G. J. Fishman and C. A. Meegan; 4. The cosmological era L. Piro and K. Hurley; 5. The Swift era N. Gehrels and D. N. Burrows; 6. Discoveries enabled by multi-wavelength afterglow observations of gamma-ray bursts J. Greiner; 7. Prompt emission from gamma-ray bursts T. Piran, R. Sari and R. Mochkovitch; 8. Basic gamma-ray burst afterglows P. Mészáros and R. A. M. J. Wijers; 9. The GRB-supernova connection J. Hjorth and J. S. Bloom; 10. Models for gamma-ray burst progenitors and central engines S. E. Woosley; 11. Jets and gamma-ray burst unification schemes J. Granot and E. Ramirez-Ruiz; 12. High-energy cosmic rays and neutrinos E. Waxman; 13. Long gamma-ray burst host galaxies and their environments J. P. U. Fynbo, D. Malesani and P. Jakobsson; 14. Gamma-ray burst cosmology V. Bromm and A. Loeb; 15. Epilogue R. D. Blandford; Index.

  13. Gamma-Ray Pulsars

    NASA Technical Reports Server (NTRS)

    Harding, Alice K.

    2011-01-01

    The Fermi Gamma-Ray Space Telescope has revolutionized the study of pulsar physics with the detection of over 80 gamma-ray pulsars. Several new populations have been discovered, including 24 radio quiet pulsars found through gamma-ray pulsations alone and about 20 millisecond gamma-ray pulsars. The gamma-ray pulsations from millisecond pulsars were discovered by both folding at periods of known radio millisecond pulsars or by detecting them as gamma-ray sources that are followed up by radio pulsar searches. The second method has resulted in a phenomenally successful synergy, with -35 new radio MSPs (to date) having been discovered at Fermi unidentified source locations and the gamma-ray pulsations having then been detected in a number of these using the radio timing solutions. The higher sensitivity and larger energy range of the Fermi Large Area Telescope has produced detailed energy-dependent light curves and phase-resolved spectroscopy on brighter pulsars, that have ruled out polar cap models as the major source of the emission in favor of outer magnetosphere accelerators. The large number of gamma-ray pulsars now allows for the first time meaningful population and sub-population studies that are revealing surprising properties of these fascinating sources.

  14. Muons in gamma showers

    NASA Technical Reports Server (NTRS)

    Stanev, T.; Vankov, C. P.; Halzen, F.

    1985-01-01

    Muon production in gamma-induced air showers, accounting for all major processes. For muon energies in the GeV region the photoproduction is by far the most important process, while the contribution of micron + micron pair creation is not negligible for TeV muons. The total rate of muons in gamma showers is, however, very low.

  15. Gamma-ray astrophysics

    NASA Technical Reports Server (NTRS)

    Stecker, F. W. (Editor); Trombka, J. I. (Editor)

    1973-01-01

    Conference papers on gamma ray astrophysics are summarized. Data cover the energy region from about 0.3 MeV to a few hundred GeV and theoretical models of production mechanisms that give rise to both galactic and extragalactic gamma rays.

  16. Optical gamma thermometer

    SciTech Connect

    Koster, Glen Peter; Xia, Hua; Lee, Boon Kwee

    2013-08-06

    An optical gamma thermometer includes a metal mass having a temperature proportional to a gamma flux within a core of a nuclear reactor, and an optical fiber cable for measuring the temperature of the heated metal mass. The temperature of the heated mass may be measured by using one or more fiber grating structures and/or by using scattering techniques, such as Raman, Brillouin, and the like. The optical gamma thermometer may be used in conjunction with a conventional reactor heat balance to calibrate the local power range monitors over their useful in-service life. The optical gamma thermometer occupies much less space within the in-core instrument tube and costs much less than the conventional gamma thermometer.

  17. Monkeys benefit from reciprocity without the cognitive burden

    PubMed Central

    Suchak, Malini; de Waal, Frans B. M.

    2012-01-01

    The debate about the origins of human prosociality has focused on the presence or absence of similar tendencies in other species, and, recently, attention has turned to the underlying mechanisms. We investigated whether direct reciprocity could promote prosocial behavior in brown capuchin monkeys (Cebus apella). Twelve capuchins tested in pairs could choose between two tokens, with one being “prosocial” in that it rewarded both individuals (i.e., 1/1), and the other being “selfish” in that it rewarded the chooser only (i.e., 1/0). Each monkey’s choices with a familiar partner from their own group was compared with choices when paired with a partner from a different group. Capuchins were spontaneously prosocial, selecting the prosocial option at the same rate regardless of whether they were paired with an in-group or out-group partner. This indicates that interaction outside of the experimental setting played no role. When the paradigm was changed, such that both partners alternated making choices, prosocial preference significantly increased, leading to mutualistic payoffs. As no contingency could be detected between an individual’s choice and their partner’s previous choice, and choices occurred in rapid succession, reciprocity seemed of a relatively vague nature akin to mutualism. Having the partner receive a better reward than the chooser (i.e., 1/2) during the alternating condition increased the payoffs of mutual prosociality, and prosocial choice increased accordingly. The outcome of several controls made it hard to explain these results on the basis of reward distribution or learned preferences, and rather suggested that joint action promotes prosociality, resulting in so-called attitudinal reciprocity. PMID:22949668

  18. Lightweight piston-rod assembly for a reciprocating machine

    DOEpatents

    Corey, John A.; Walsh, Michael M.

    1986-01-01

    In a reciprocating machine, there is provided a hollow piston including a dome portion on one end and a base portion on the opposite end. The base portion includes a central bore into which a rod is hermetically fixed in radial and angular alignment. The extending end of the rod has a reduced diameter portion adapted to fit into the central bore of a second member such as a cross-head assembly, and to be secured thereto in radial and axial alignment with the piston.

  19. Organic rankine cycle system for use with a reciprocating engine

    DOEpatents

    Radcliff, Thomas D.; McCormick, Duane; Brasz, Joost J.

    2006-01-17

    In a waste heat recovery system wherein an organic rankine cycle system uses waste heat from the fluids of a reciprocating engine, provision is made to continue operation of the engine even during periods when the organic rankine cycle system is inoperative, by providing an auxiliary pump and a bypass for the refrigerant flow around the turbine. Provision is also made to divert the engine exhaust gases from the evaporator during such periods of operation. In one embodiment, the auxiliary pump is made to operate simultaneously with the primary pump during normal operations, thereby allowing the primary pump to operate at lower speeds with less likelihood of cavitation.

  20. On the characteristics of centrifugal-reciprocating machines. [cryogenic coolers

    NASA Technical Reports Server (NTRS)

    Higa, W. H.

    1980-01-01

    A method of compressing helium gas for cryogenic coolers is presented which uses centrifugal force to reduce the forces on the connecting rod and crankshaft in the usual reciprocating compressor. This is achieved by rotating the piston-cylinder assembly at a speed sufficient for the centrifugal force on the piston to overcome the compressional force due to the working fluid. The rotating assembly is dynamically braked in order to recharge the working space with fluid. The intake stroke consists of decelerating the rotating piston-cylinder assembly and the exhaust stroke consists of accelerating the assembly.

  1. Principle of reciprocity solves the most important problems in bioimpedance and in general in bioelectromagnetism

    NASA Astrophysics Data System (ADS)

    Malmivuo, Jaakko

    2010-04-01

    Though the principle of reciprocity was invented by Hermann von Helmholtz already over 150 years ago, and though it is a very powerful tool in solving various important problems in bioelectromagnetism, it is not generally used. In impedance tomography the measurement sensitivity distribution has generally been misunderstood. This can be easily demonstrated with the principle of reciprocity. Some other applications of the principle of reciprocity are also discussed.

  2. Model of Wikipedia growth based on information exchange via reciprocal arcs

    NASA Astrophysics Data System (ADS)

    Zlatić, V.; Štefančić, H.

    2011-03-01

    We show how reciprocal arcs significantly influence the structural organization of Wikipedias, online encyclopedias. It is shown that random addition of reciprocal arcs in the static network cannot explain the observed reciprocity of Wikipedias. A model of Wikipedia growth based on preferential attachment and on information exchange via reciprocal arcs is presented. An excellent agreement between in-degree distributions of our model and real Wikipedia networks is achieved without fitting the distributions, but by merely extracting a small number of model parameters from the measurement of real networks.

  3. Gamma-interferon alters globin gene expression in neonatal and adult erythroid cells

    SciTech Connect

    Miller, B.A.; Perrine, S.P.; Antognetti, G.; Perlmutter, D.H.; Emerson, S.G.; Sieff, C.; Faller, D.V.

    1987-06-01

    The effect of gamma-interferon on fetal hemoglobin synthesis by purified cord blood, fetal liver, and adult bone marrow erythroid progenitors was studied with a radioligand assay to measure hemoglobin production by BFU-E-derived erythroblasts. Coculture with recombinant gamma-interferon resulted in a significant and dose-dependent decrease in fetal hemoglobin production by neonatal and adult, but not fetal, BFU-E-derived erythroblasts. Accumulation of fetal hemoglobin by cord blood BFU-E-derived erythroblasts decreased up to 38.1% of control cultures (erythropoietin only). Synthesis of both G gamma/A gamma globin was decreased, since the G gamma/A gamma ratio was unchanged. Picograms fetal hemoglobin per cell was decreased by gamma-interferon addition, but picograms total hemoglobin was unchanged, demonstrating that a reciprocal increase in beta-globin production occurred in cultures treated with gamma-interferon. No toxic effect of gamma-interferon on colony growth was noted. The addition of gamma-interferon to cultures resulted in a decrease in the percentage of HbF produced by adult BFU-E-derived cells to 45.6% of control. Fetal hemoglobin production by cord blood, fetal liver, and adult bone marrow erythroid progenitors, was not significantly affected by the addition of recombinant GM-CSF, recombinant interleukin 1 (IL-1), recombinant IL-2, or recombinant alpha-interferon. Although fetal progenitor cells appear unable to alter their fetal hemoglobin program in response to any of the growth factors added here, the interaction of neonatal and adult erythroid progenitors with gamma-interferon results in an altered expression of globin genes.

  4. Sublethal gamma irradiation affects reproductive impairment and elevates antioxidant enzyme and DNA repair activities in the monogonont rotifer Brachionus koreanus.

    PubMed

    Han, Jeonghoon; Won, Eun-Ji; Kim, Il-Chan; Yim, Joung Han; Lee, Su-Jae; Lee, Jae-Seong

    2014-10-01

    To examine the effects of gamma radiation on marine organisms, we irradiated several doses of gamma ray to the microzooplankton Brachionus koreanus, and measured in vivo and in vitro endpoints including the survival rate, lifespan, fecundity, population growth, gamma ray-induced oxidative stress, and modulated patterns of enzyme activities and gene expressions after DNA damage. After gamma radiation, no individuals showed any mortality within 96 h even at a high intensity (1200 Gy). However, a reduced fecundity (e.g. cumulated number of offspring) of B. koreanus at over 150 Gy was observed along with a slight decrease in lifespan. At 150 Gy and 200 Gy, the reduced fecundity of the rotifers led to a significant decrease in population growth, although in the second generation the population growth pattern was not affected even at 200 Gy when compared to the control group. At sub-lethal doses, reactive oxygen species (ROS) levels dose-dependently increased with GST enzyme activity. In addition, up-regulations of the antioxidant and chaperoning genes in response to gamma radiation were able to recover cellular damages, and life table parameters were significantly influenced, particularly with regard to fecundity. DNA repair-associated genes showed significantly up-regulated expression patterns in response to sublethal doses (150 and 200 Gy), as shown in the expression of the gamma-irradiated B. koreanus p53 gene, suggesting that these sublethal doses were not significantly fatal to B. koreanus but induced DNA damages leading to a decrease of the population size.

  5. Analyses of cosmic ray induced-neutron based on spectrometers operated simultaneously at mid-latitude and Antarctica high-altitude stations during quiet solar activity

    NASA Astrophysics Data System (ADS)

    Hubert, G.

    2016-10-01

    In this paper are described a new neutron spectrometer which operate in the Concordia station (Antarctica, Dome C) since December 2015. This instrument complements a network including neutron spectrometers operating in the Pic-du-Midi and the Pico dos Dias. Thus, this work present an analysis of cosmic ray induced-neutron based on spectrometers operated simultaneously in the Pic-du-Midi and the Concordia stations during a quiet solar activity. The both high station platforms allow for investigating the long period dynamics to analyze the spectral variation and effects of local and seasonal changes, but also the short term dynamics during solar flare events. A first part is devoted to analyze the count rates, the spectrum and the neutron fluxes, implying cross-comparisons between data obtained in the both stations. In a second part, measurements analyses were reinforced by modeling based on simulations of atmospheric cascades according to primary spectra which only depend on the solar modulation potential.

  6. Neutron-induced gamma ray spectroscopy: Simulations for chemical mapping of planetary surfaces

    NASA Astrophysics Data System (ADS)

    Brückner, J.; Wänke, H.; Reedy, R. C.

    Cosmic rays interact with the surface of a planetary body and produce a cascade of secondary particles, such as neutrons. Neutron-induced scattering and capture reactions play an important role in the production of discrete gamma ray lines that can be measured by a gamma ray spectrometer on board an orbiting spacecraft. These data can be used to determine the concentration of many elements in the surface of a planetary body, which enables us to recognize individual geological units and provides clues to the bulk composition and in turn the origin and evolution of the body. To investigate the gamma ray fluxes induced by accelerator neutrons, experiments were carried out by irradiating thin targets with neutrons of energies from 14 MeV to 0.025 eV. The neutron fluxes at target position were measured by foil activation techniques. The ratio of the epithermal to thermal neutron flux was determined to be 2.0, a value that is similar to that in the moon. Gamma rays in the energy range of 0.1 to 8 MeV emitted by the targets and the surrounding material were measured by a high-resolution germanium detector. Most of the gamma ray lines that are expected to be used for planetary gamma ray Spectroscopy were found in the recorded spectra. These spectra were unfolded, background was subtracted, and gamma ray attenuation corrections were made to obtain the corresponding gamma ray fluxes from the targets. The majority of gamma ray lines were narrow without noticeable Doppler broadening except for the very broad 4.4-MeV line of carbon and five asymmetric germanium lines produced by the detector itself. The agreement of measured gamma ray flux ratios with calculated flux ratios for neutron-capture reactions showed that thermal neutron data can be used for theoretical calculations of low-energy neutron-induced gamma ray fluxes. This study was a first step toward a more realistic simulation of cosmic-ray-induced gamma-ray production and it indicates the importance of accelerator

  7. Neutron-induced gamma ray spectroscopy: Simulations for chemical mapping of planetary surfaces

    NASA Astrophysics Data System (ADS)

    Brückner, J.; Wänke, H.; Reedy, R. C.

    1987-09-01

    Cosmic rays interact with the surface of a planetary body and produce a cascade of secondary particles, such as neutrons. Neutron-induced scattering and capture reactions play an important role in the production of discrete gamma ray lines that can be measured by a gamma ray spectrometer on board an orbiting spacecraft. These data can be used to determine the concentration of many elements in the surface of a planetary body, which enables us to recognize individual geological units and provides clues to the bulk composition and in turn the origin and evolution of the body. To investigate the gamma ray fluxes induced by accelerator neutrons, experiments were carried out by irradiating thin targets with neutrons of energies from 14 MeV to 0.025 eV. The neutron fluxes at target position were measured by foil activation techniques. The ratio of the epithermal to thermal neutron flux was determined to be 2.0, a value that is similar to that in the moon. Gamma rays in the energy range of 0.1 to 8 MeV emitted by the targets and the surrounding material were measured by a high-resolution germanium detector. Most of the gamma ray lines that are expected to be used for planetary gamma ray spectroscopy were found in the recorded spectra. These spectra were unfolded, background was subtracted, and gamma ray attenuation corrections were made to obtain the corresponding gamma ray fluxes from the targets. The majority of gamma ray lines were narrow without noticeable Doppler broadening except for the very broad 4.4-MeV line of carbon and five asymmetric germanium lines produced by the detector itself. The agreement of measured gamma ray flux ratios with calculated flux ratios for neutron-capture reactions showed that thermal neutron data can be used for theoretical calculations of low-energy neutron-induced gamma ray fluxes. This study was a first step toward a more realistic simulation of cosmic-ray-induced gamma-ray production and it indicates the importance of accelerator

  8. Insight into the so-called spatial reciprocity.

    PubMed

    Wang, Zhen; Kokubo, Satoshi; Tanimoto, Jun; Fukuda, Eriko; Shigaki, Keizo

    2013-10-01

    Up to now, there have been a great number of studies that demonstrate the effect of spatial topology on the promotion of cooperation dynamics (namely, the so-called "spatial reciprocity"). However, most researchers probably attribute it to the positive assortment of strategies supported by spatial arrangement. In this paper, we analyze the time course of cooperation evolution under different evolution rules. Interestingly, a typical evolution process can be divided into two evident periods: the enduring (END) period and the expanding (EXP) period where the former features that cooperators try to endure defectors' invasion and the latter shows that perfect C clusters fast expand their area. We find that the final cooperation level relies on two key factors: the formation of the perfect C cluster at the end of the END period and the expanding fashion of the perfect C cluster during the EXP period. For deterministic rule, the smooth expansion of C cluster boundaries enables cooperators to reach a dominant state, whereas, the rough boundaries for stochastic rule cannot provide a sufficient beneficial environment for the evolution of cooperation. Moreover, we show that expansion of the perfect C cluster is closely related to the cluster coefficient of interaction topology. To some extent, we present a viable method for understanding the spatial reciprocity mechanism in nature and hope that it will inspire further studies to resolve social dilemmas.

  9. The Role of Reciprocity in Verbally Persuasive Robots.

    PubMed

    Lee, Seungcheol Austin; Liang, Yuhua Jake

    2016-08-01

    The current research examines the persuasive effects of reciprocity in the context of human-robot interaction. This is an important theoretical and practical extension of persuasive robotics by testing (1) if robots can utilize verbal requests and (2) if robots can utilize persuasive mechanisms (e.g., reciprocity) to gain human compliance. Participants played a trivia game with a robot teammate. The ostensibly autonomous robot helped (or failed to help) the participants by providing the correct (vs. incorrect) trivia answers. Then, the robot directly asked participants to complete a 15-minute task for pattern recognition. Compared to no help, results showed that a robot's prior helping behavior significantly increased the likelihood of compliance (60 percent vs. 33 percent). Interestingly, participants' evaluations toward the robot (i.e., competence, warmth, and trustworthiness) did not predict compliance. These results also provided an insightful comparison showing that participants complied at similar rates with the robot and with computer agents. This result documents a clear empirically powerful potential for the role of verbal messages in persuasive robotics. PMID:27447027

  10. Comparing reactive and memory-one strategies of direct reciprocity

    PubMed Central

    Baek, Seung Ki; Jeong, Hyeong-Chai; Hilbe, Christian; Nowak, Martin A.

    2016-01-01

    Direct reciprocity is a mechanism for the evolution of cooperation based on repeated interactions. When individuals meet repeatedly, they can use conditional strategies to enforce cooperative outcomes that would not be feasible in one-shot social dilemmas. Direct reciprocity requires that individuals keep track of their past interactions and find the right response. However, there are natural bounds on strategic complexity: Humans find it difficult to remember past interactions accurately, especially over long timespans. Given these limitations, it is natural to ask how complex strategies need to be for cooperation to evolve. Here, we study stochastic evolutionary game dynamics in finite populations to systematically compare the evolutionary performance of reactive strategies, which only respond to the co-player’s previous move, and memory-one strategies, which take into account the own and the co-player’s previous move. In both cases, we compare deterministic strategy and stochastic strategy spaces. For reactive strategies and small costs, we find that stochasticity benefits cooperation, because it allows for generous-tit-for-tat. For memory one strategies and small costs, we find that stochasticity does not increase the propensity for cooperation, because the deterministic rule of win-stay, lose-shift works best. For memory one strategies and large costs, however, stochasticity can augment cooperation. PMID:27161141

  11. Quadratic Reciprocity and the Group Orders of Particle States

    SciTech Connect

    DAI,YANG; BORISOV,ALEXEY B.; LONGWORTH,JAMES W.; BOYER,KEITH; RHODES,CHARLES K.

    2001-06-01

    The construction of inverse states in a finite field F{sub P{sub P{alpha}}} enables the organization of the mass scale by associating particle states with residue class designations. With the assumption of perfect flatness ({Omega}total = 1.0), this approach leads to the derivation of a cosmic seesaw congruence which unifies the concepts of space and mass. The law of quadratic reciprocity profoundly constrains the subgroup structure of the multiplicative group of units F{sub P{sub {alpha}}}* defined by the field. Four specific outcomes of this organization are (1) a reduction in the computational complexity of the mass state distribution by a factor of {approximately}10{sup 30}, (2) the extension of the genetic divisor concept to the classification of subgroup orders, (3) the derivation of a simple numerical test for any prospective mass number based on the order of the integer, and (4) the identification of direct biological analogies to taxonomy and regulatory networks characteristic of cellular metabolism, tumor suppression, immunology, and evolution. It is generally concluded that the organizing principle legislated by the alliance of quadratic reciprocity with the cosmic seesaw creates a universal optimized structure that functions in the regulation of a broad range of complex phenomena.

  12. The competition of assessment rules for indirect reciprocity.

    PubMed

    Uchida, Satoshi; Sigmund, Karl

    2010-03-01

    Indirect reciprocity is one of the basic mechanisms to sustain mutual cooperation. Beneficial acts are returned, not by the recipient, but by third parties. Indirect reciprocity is based on reputation and status: it pays to provide help because this makes one more likely to receive help in turn. The mechanism depends on knowing the past behavior of other players, and assessing that behavior. There are many different systems of assessing other individuals, which can be interpreted as rudimentary moral systems (i.e. views on what is 'good' or 'bad'). In this paper, we describe the competition of some of the leading assessment rules called SUGDEN and KANDORI by analytic methods. We show that the sterner rule KANDORI has a slight advantage in the sense that KANDORI-players have more chance to earn higher payoff than SUGDEN-players in the presence of unconditional altruists. On the other hand, we see that the unconditional altruists are eliminated in the long run and that stable polymorphisms of KANDORI and SUGDEN can subsist, but that a moral consensus is realized even in those polymorphic states: all players' images are the same in each observer's eyes.

  13. Reciprocal evolution of the cerebellum and neocortex in fossil humans.

    PubMed

    Weaver, Anne H

    2005-03-01

    Human brain evolution involved both neurological reorganization and an increase in overall brain volume relative to body mass. It is generally difficult to draw functional inferences about the timing and nature of brain reorganization, given that superficial brain morphology recorded on fossil endocasts is functionally ambiguous. However, the cerebellum, housed in the clearly delineated posterior cranial fossa, is functionally and ontologically discrete. The cerebellum is reciprocally connected to each of 14 neocortical regions important to human cognitive evolution. Cerebellar volume varies significantly relative to overall brain volume among mammalian orders, as well as within the primate order. There is also significant diachronic variation among fossil human taxa. In the australopithecines and early members of the genus Homo, the cerebral hemispheres were large in proportion to the cerebellum, compared with other hominoids. This trend continued in Middle and Late Pleistocene humans, including Neandertals and Cro-Magnon 1, who have the largest cerebral hemispheres relative to cerebellum volume of any primates, including earlier and Holocene humans. In recent humans, however, the pattern is reversed; the cerebellum is larger with respect to the rest of the brain (and, conversely, the cerebral hemispheres are smaller with respect to the cerebellum) than in Late Pleistocene humans. The cerebellum and cerebral hemispheres appear to have evolved reciprocally. Cerebellar development in Holocene humans may have provided greater computational efficiency for coping with an increasingly complex cultural and conceptual environment.

  14. Reciprocal evolution of the cerebellum and neocortex in fossil humans

    PubMed Central

    Weaver, Anne H.

    2005-01-01

    Human brain evolution involved both neurological reorganization and an increase in overall brain volume relative to body mass. It is generally difficult to draw functional inferences about the timing and nature of brain reorganization, given that superficial brain morphology recorded on fossil endocasts is functionally ambiguous. However, the cerebellum, housed in the clearly delineated posterior cranial fossa, is functionally and ontologically discrete. The cerebellum is reciprocally connected to each of 14 neocortical regions important to human cognitive evolution. Cerebellar volume varies significantly relative to overall brain volume among mammalian orders, as well as within the primate order. There is also significant diachronic variation among fossil human taxa. In the australopithecines and early members of the genus Homo, the cerebral hemispheres were large in proportion to the cerebellum, compared with other hominoids. This trend continued in Middle and Late Pleistocene humans, including Neandertals and Cro-Magnon 1, who have the largest cerebral hemispheres relative to cerebellum volume of any primates, including earlier and Holocene humans. In recent humans, however, the pattern is reversed; the cerebellum is larger with respect to the rest of the brain (and, conversely, the cerebral hemispheres are smaller with respect to the cerebellum) than in Late Pleistocene humans. The cerebellum and cerebral hemispheres appear to have evolved reciprocally. Cerebellar development in Holocene humans may have provided greater computational efficiency for coping with an increasingly complex cultural and conceptual environment. PMID:15731345

  15. Reciprocal evolution of the cerebellum and neocortex in fossil humans.

    PubMed

    Weaver, Anne H

    2005-03-01

    Human brain evolution involved both neurological reorganization and an increase in overall brain volume relative to body mass. It is generally difficult to draw functional inferences about the timing and nature of brain reorganization, given that superficial brain morphology recorded on fossil endocasts is functionally ambiguous. However, the cerebellum, housed in the clearly delineated posterior cranial fossa, is functionally and ontologically discrete. The cerebellum is reciprocally connected to each of 14 neocortical regions important to human cognitive evolution. Cerebellar volume varies significantly relative to overall brain volume among mammalian orders, as well as within the primate order. There is also significant diachronic variation among fossil human taxa. In the australopithecines and early members of the genus Homo, the cerebral hemispheres were large in proportion to the cerebellum, compared with other hominoids. This trend continued in Middle and Late Pleistocene humans, including Neandertals and Cro-Magnon 1, who have the largest cerebral hemispheres relative to cerebellum volume of any primates, including earlier and Holocene humans. In recent humans, however, the pattern is reversed; the cerebellum is larger with respect to the rest of the brain (and, conversely, the cerebral hemispheres are smaller with respect to the cerebellum) than in Late Pleistocene humans. The cerebellum and cerebral hemispheres appear to have evolved reciprocally. Cerebellar development in Holocene humans may have provided greater computational efficiency for coping with an increasingly complex cultural and conceptual environment. PMID:15731345

  16. Earning points for moral behavior: organ allocation based on reciprocity.

    PubMed

    Ravelingien, An; Krom, Andre

    2005-01-01

    Anticipating the reevaluation of the Dutch organ procurement system, in late 2003 the Rathenau Institute published a study entitled 'Gift or Contribution?' In this study, the author, Govert den Hartogh, carries out a thorough moral analysis of the problem of organ shortage and fair allocation of organs. He suggests there should be a change in mentality whereby organ donation is no longer viewed in terms of charity and the volunteer spirit, but rather in terms of duty and reciprocity. The procurement and allocation of donor organs should be seen as a system of mutually assured help. Fair allocation would imply to give priority to those who recognize and comply with their duty: the registered donors. The idea of viewing organ donation as an undertaking involving mutual benefit rather than as a matter of charity, however, is not new. Notwithstanding the fact that reference to charity and altruism is not required in order for the organ donation to be of moral significance, we will argue against the reciprocity-based scenario. Steering organ allocation towards those who are themselves willing to donate organs is both an ineffective and morally questionable means of attempting to counter organ shortage.

  17. The Role of Reciprocity in Verbally Persuasive Robots.

    PubMed

    Lee, Seungcheol Austin; Liang, Yuhua Jake

    2016-08-01

    The current research examines the persuasive effects of reciprocity in the context of human-robot interaction. This is an important theoretical and practical extension of persuasive robotics by testing (1) if robots can utilize verbal requests and (2) if robots can utilize persuasive mechanisms (e.g., reciprocity) to gain human compliance. Participants played a trivia game with a robot teammate. The ostensibly autonomous robot helped (or failed to help) the participants by providing the correct (vs. incorrect) trivia answers. Then, the robot directly asked participants to complete a 15-minute task for pattern recognition. Compared to no help, results showed that a robot's prior helping behavior significantly increased the likelihood of compliance (60 percent vs. 33 percent). Interestingly, participants' evaluations toward the robot (i.e., competence, warmth, and trustworthiness) did not predict compliance. These results also provided an insightful comparison showing that participants complied at similar rates with the robot and with computer agents. This result documents a clear empirically powerful potential for the role of verbal messages in persuasive robotics.

  18. A magnetic non-reciprocal isolator for broadband terahertz operation

    PubMed Central

    Shalaby, Mostafa; Peccianti, Marco; Ozturk, Yavuz; Morandotti, Roberto

    2013-01-01

    A Faraday isolator is an electromagnetic non-reciprocal device, a key element in photonics. It is required to shield electromagnetic sources against the effect of back-reflected light, as well as to limit the detrimental effect of back-propagating spontaneous emissions. A common isolator variant, the circulator, is widely used to obtain a complete separation between forward- and backward-propagating waves, thus enabling the realization of a desired transfer function in reflection only. Here we demonstrate a non-reciprocal terahertz Faraday isolator, operating on a bandwidth exceeding one decade of frequency, a necessary requirement to achieve isolation with the (few-cycle) pulses generated by broadband sources. The exploited medium allows a broadband rotation, up to 194°/T, obtained using a SrFe12O19 terahertz-transparent permanent magnet. This in turn enables the design of a stand-alone complete terahertz isolator without resorting to an external magnetic field bias, as opposed to all the optical isolators realized so far. PMID:23463001

  19. A magnetic non-reciprocal isolator for broadband terahertz operation

    NASA Astrophysics Data System (ADS)

    Shalaby, Mostafa; Peccianti, Marco; Ozturk, Yavuz; Morandotti, Roberto

    2013-03-01

    A Faraday isolator is an electromagnetic non-reciprocal device, a key element in photonics. It is required to shield electromagnetic sources against the effect of back-reflected light, as well as to limit the detrimental effect of back-propagating spontaneous emissions. A common isolator variant, the circulator, is widely used to obtain a complete separation between forward- and backward-propagating waves, thus enabling the realization of a desired transfer function in reflection only. Here we demonstrate a non-reciprocal terahertz Faraday isolator, operating on a bandwidth exceeding one decade of frequency, a necessary requirement to achieve isolation with the (few-cycle) pulses generated by broadband sources. The exploited medium allows a broadband rotation, up to 194°/T, obtained using a SrFe12O19 terahertz-transparent permanent magnet. This in turn enables the design of a stand-alone complete terahertz isolator without resorting to an external magnetic field bias, as opposed to all the optical isolators realized so far.

  20. A magnetic non-reciprocal isolator for broadband terahertz operation.

    PubMed

    Shalaby, Mostafa; Peccianti, Marco; Ozturk, Yavuz; Morandotti, Roberto

    2013-01-01

    A Faraday isolator is an electromagnetic non-reciprocal device, a key element in photonics. It is required to shield electromagnetic sources against the effect of back-reflected light, as well as to limit the detrimental effect of back-propagating spontaneous emissions. A common isolator variant, the circulator, is widely used to obtain a complete separation between forward- and backward-propagating waves, thus enabling the realization of a desired transfer function in reflection only. Here we demonstrate a non-reciprocal terahertz Faraday isolator, operating on a bandwidth exceeding one decade of frequency, a necessary requirement to achieve isolation with the (few-cycle) pulses generated by broadband sources. The exploited medium allows a broadband rotation, up to 194°/T, obtained using a SrFe12O19 terahertz-transparent permanent magnet. This in turn enables the design of a stand-alone complete terahertz isolator without resorting to an external magnetic field bias, as opposed to all the optical isolators realized so far. PMID:23463001

  1. Fast reciprocating Langmuir probe for the DIII-D divertor

    NASA Astrophysics Data System (ADS)

    Watkins, J. G.; Hunter, J.; Tafoya, B.; Ulrickson, M.; Watson, R. D.; Moyer, R. A.; Cuthbertson, J. W.; Gunner, G.; Lehmer, R.; Luong, P.; Hill, D. N.; Mascaro, M.; Robinson, J. I.; Snider, R.; Stambaugh, R.

    1997-01-01

    A new reciprocating Langmuir probe was used to measure density and temperature profiles, ion flow, and potential fluctuation levels from the lower divertor floor up to the X point on the DIII-D Tokamak. This probe is designed to make fast (2 kHz swept, 20 kHz Mach, 500 kHz Vfloat) measurements with 2 mm spatial resolution in the region where the largest gradients on the plasma open flux tubes are found and therefore provide the best benchmarks for scrap-off layer and divertor numerical models. Profiles are constructed using the 300 ms time history of the probe measurements during the 25 cm reciprocating stroke. Both single and double null plasmas can be measured and compared with a 20 Hz divertor Thomson scattering system. The probe head is constructed of four different kinds of graphite to optimize the electrical and thermal characteristics. Electrically insulated pyrolytic graphite rings act as a heat shield to absorb the plasma heat flux on the probe shaft and are mounted on a carbon/carbon composite core for mechanical strength. The Langmuir probe sampling tips are made of a linear carbon fiber composite. The mechanical, electrical, data acquisition, and power supply systems will be described. Initial measurements will also be presented.

  2. Peltier cooling and onsager reciprocity in ferromagnetic thin films.

    PubMed

    Avery, A D; Zink, B L

    2013-09-20

    We present direct measurements of the Peltier effect as a function of temperature from 77 to 325 K in Ni, Ni(80)Fe(20), and Fe thin films made using a suspended Si-N membrane structure. Measurement of the Seebeck effect in the same films allows us to directly test predictions of Onsager reciprocity between the Peltier and Seebeck effects. The Peltier coefficient Π is negative for both Ni and Ni(80)Fe(20) films and positive for the Fe film. The Fe film also exhibits a peak associated with the magnon drag Peltier effect. The observation of magnon drag in the Fe film verifies that the coupling between the phonon, magnon, and electron systems in the film is the same whether driven by heat current or charge current. The excellent agreement between Π values predicted using the experimentally determined Seebeck coefficient for these films and measured values offers direct experimental confirmation of the Onsager reciprocity between these thermoelectric effects in ferromagnetic thin films near room temperature.

  3. LES on unstructured deforming meshes: Towards reciprocating IC engines

    NASA Technical Reports Server (NTRS)

    Haworth, D. C.; Jansen, K.

    1996-01-01

    A variable explicit/implicit characteristics-based advection scheme that is second-order accurate in space and time has been developed recently for unstructured deforming meshes (O'Rourke & Sahota 1996a). To explore the suitability of this methodology for Large-Eddy Simulation (LES), three subgrid-scale turbulence models have been implemented in the CHAD CFD code (O'Rourke & Sahota 1996b): a constant-coefficient Smagorinsky model, a dynamic Smagorinsky model for flows having one or more directions of statistical homogeneity, and a Lagrangian dynamic Smagorinsky model for flows having no spatial or temporal homogeneity (Meneveau et al. 1996). Computations have been made for three canonical flows, progressing towards the intended application of in-cylinder flow in a reciprocating engine. Grid sizes were selected to be comparable to the coarsest meshes used in earlier spectral LES studies. Quantitative results are reported for decaying homogeneous isotropic turbulence, and for a planar channel flow. Computations are compared to experimental measurements, to Direct-Numerical Simulation (DNS) data, and to Rapid-Distortion Theory (RDT) where appropriate. Generally satisfactory evolution of first and second moments is found on these coarse meshes; deviations are attributed to insufficient mesh resolution. Issues include mesh resolution and computational requirements for a specified level of accuracy, analytic characterization of the filtering implied by the numerical method, wall treatment, and inflow boundary conditions. To resolve these issues, finer-mesh simulations and computations of a simplified axisymmetric reciprocating piston-cylinder assembly are in progress.

  4. Comparing reactive and memory-one strategies of direct reciprocity

    NASA Astrophysics Data System (ADS)

    Baek, Seung Ki; Jeong, Hyeong-Chai; Hilbe, Christian; Nowak, Martin A.

    2016-05-01

    Direct reciprocity is a mechanism for the evolution of cooperation based on repeated interactions. When individuals meet repeatedly, they can use conditional strategies to enforce cooperative outcomes that would not be feasible in one-shot social dilemmas. Direct reciprocity requires that individuals keep track of their past interactions and find the right response. However, there are natural bounds on strategic complexity: Humans find it difficult to remember past interactions accurately, especially over long timespans. Given these limitations, it is natural to ask how complex strategies need to be for cooperation to evolve. Here, we study stochastic evolutionary game dynamics in finite populations to systematically compare the evolutionary performance of reactive strategies, which only respond to the co-player’s previous move, and memory-one strategies, which take into account the own and the co-player’s previous move. In both cases, we compare deterministic strategy and stochastic strategy spaces. For reactive strategies and small costs, we find that stochasticity benefits cooperation, because it allows for generous-tit-for-tat. For memory one strategies and small costs, we find that stochasticity does not increase the propensity for cooperation, because the deterministic rule of win-stay, lose-shift works best. For memory one strategies and large costs, however, stochasticity can augment cooperation.

  5. Contingent movement and cooperation evolve under generalized reciprocity.

    PubMed

    Hamilton, Ian M; Taborsky, Michael

    2005-11-01

    How cooperation and altruism among non-relatives can persist in the face of cheating remains a key puzzle in evolutionary biology. Although mechanisms such as direct and indirect reciprocity and limited movement have been put forward to explain such cooperation, they cannot explain cooperation among unfamiliar, highly mobile individuals. Here we show that cooperation may be evolutionarily stable if decisions taken to cooperate and to change group membership are both dependent on anonymous social experience (generalized reciprocity). We find that a win-stay, lose-shift rule (where shifting is either moving away from the group or changing tactics within the group after receiving defection) evolves in evolutionary simulations when group leaving is moderately costly (i.e. the current payoff to being alone is low, but still higher than that in a mutually defecting group, and new groups are rarely encountered). This leads to the establishment of widespread cooperation in the population. If the costs of group leaving are reduced, a similar group-leaving rule evolves in association with cooperation in pairs and exploitation of larger anonymous groups. We emphasize that mechanisms of assortment within populations are often behavioural decisions and should not be considered independently of the evolution of cooperation.

  6. Unique airborne measurements at the tropopause of Fukushima Xe-133, aerosol, and aerosol precursors indicate aerosol formation via homogeneous and cosmic ray induced nucleation

    NASA Astrophysics Data System (ADS)

    Schlager, Hans; Arnold, Frank; Aufmhoff, Heinfried; Minikin, Andreas; Baumann, Robert; Simgen, Hardy; Lindemann, Stefan; Rauch, Ludwig; Kaether, Frank; Pirjola, Liisa; Schumann, Ulrich

    2014-05-01

    We report unique airborne measurements, at the tropopause, of the Fukushima radio nuclide Xe-133, aerosol particles (size, shape, number concentration, volatility), aerosol precursor gases (particularly SO2, HNO3, H2O). Our measurements and accompanying model simulations indicate homogeneous and cosmic ray induced aerosol formation at the tropopause. Using an extremely sensitive detection method, we managed to detect Fukushima Xe-133, an ideal transport tracer, at and even above the tropopause. To our knowledge, these airborne Xe-133 measurements are the only of their kind. Our investigations represent a striking example how a pioneering measurement of a Fukshima radio nuclide, employing an extremely sensitive method, can lead to new insights into an important atmospheric process. After the Fukushima accidential Xe-133 release (mostly during 11-15 March 2011), we have conducted two aircraft missions, which took place over Central Europe, on 23 March and 11 April 2011. In the air masses, encountered by the research aircraft on 23 March, we have detected Fukushima Xe-133 by an extremely sensitive method, at and even above the tropopause. Besides increased concentrations of Xe-133, we have detected also increased concentrations of the gases SO2, HNO3, and H2O. The Xe-133 data and accompanying transport model simulations indicate that a West-Pacific Warm Conveyor Belt (WCB) lifted East-Asian planetary boundary layer air to and even above the tropopause, followed by relatively fast quasi-horizontal advection to Europe. Along with Xe-133, anthropogenic SO2, NOx (mostly released from East-Asian ground-level combustion sources), and warer vapour were also lifted by the WCB. After the lift, SO2 and NOx experienced efficient solar UV-radiation driven conversion to the important aerosol precursors gases H2SO4 and HNO3. Our investigations indicate that, increased concentrations of the gases SO2, HNO3, and H2O promoted homogeneous and cosmic ray induced aerosol formation at and

  7. Prospects for gamma ray astronomy

    NASA Technical Reports Server (NTRS)

    1981-01-01

    The Solar Maximum Mission and the Gamma Ray Experiment aboard the SMM spacecraft are discussed. Mission plans for interplanetary probes are also discussed. The Gamma Ray observatory and its role in future gamma ray astronomy is highlighted. It is concluded that gamma ray astronomy will be of major importance in the development of astronomical models and in the development of comsological theory.

  8. The gamma-ray observatory

    NASA Technical Reports Server (NTRS)

    1991-01-01

    An overview is given of the Gamma Ray Observatory (GRO) mission. Detection of gamma rays and gamma ray sources, operations using the Space Shuttle, and instruments aboard the GRO, including the Burst and Transient Source Experiment (BATSE), the Oriented Scintillation Spectrometer Experiment (OSSE), the Imaging Compton Telescope (COMPTEL), and the Energetic Gamma Ray Experiment Telescope (EGRET) are among the topics surveyed.

  9. Gamma-ray astronomy

    NASA Technical Reports Server (NTRS)

    Ramaty, R.; Lingenfelter, R. E.

    1982-01-01

    Cosmic gamma rays, the physical processes responsible for their production and the astrophysical sites from which they were seen are reported. The bulk of the observed gamma ray emission is in the photon energy range from about 0.1 MeV to 1 GeV, where observations are carried out above the atmosphere. There are also, however, gamma ray observations at higher energies obtained by detecting the Cerenkov light produced by the high energy photons in the atmosphere. Gamma ray emission was observed from sources as close as the Sun and the Moon and as distant as the quasar 3C273, as well as from various other galactic and extragalactic sites. The radiation processes also range from the well understood, e.g. energetic particle interactions with matter, to the still incompletely researched, such as radiation transfer in optically thick electron positron plasmas in intense neutron star magnetic fields.

  10. Gamma ray astronomy

    NASA Technical Reports Server (NTRS)

    Paciesas, William S.

    1991-01-01

    Miscellaneous tasks related to the development of the Bursts and Transient Source Experiment on the Gamma Ray Observatory and to analysis of archival data from balloon flight experiments were performed. The results are summarized and relevant references are included.

  11. Gamma ray line astronomy

    NASA Technical Reports Server (NTRS)

    Ramaty, R.

    1984-01-01

    The interpretations and implications of the astrophysical observations of gamma-ray lines are reviewed. At the Galactic Center e(+)-e(-) pairs from a compact object produce an annihilation line that shows no redshift, indicating an annihilation site far removed from this object. In the jets of SS433, gamma-ray lines are produced by inelastic excitations, probably in dust grains, although line emission from fusion reactions has also been considered. Observations of diffuse galactic line emission reveal recently synthesized radioactive aluminum in the interstellar medium. In gamma-ray bursts, redshifted pair annihilation lines are consistent with a neutron star origin for the bursts. In solar flares, gamma-ray line emission reveals the prompt acceleration of protons and nuclei, in close association with the flare energy release mechanism.

  12. Protection by WR-2721 and WR-151327 against late effects of gamma rays and neutrons

    NASA Astrophysics Data System (ADS)

    Grdina, D. J.; Garnes, B. A.; Nagy, B.

    Two thiophosphoroate compounds WR-2721 and WR-151327 were assessed for their ability to modify the deleterious effects (life shortening and carcinogenesis) of fission-spectrum neutrons (kerma-weighted mean energy of 0.85 MeV) or gamma rays on B6CF1 hybrid mice. Male and female mice, 200 of each sex per experimental group, were irradiated individually at 110 days of age. Radioprotectors (400 mg/kg of WR-2721 or 580 mg/kg of WR-151327) were administered intraperitoneally 30 min prior to irradiation. Neutron doses were 10 cGy or 40 cGy and gamma ray doses were 206 cGy or 417 cGy. Animals were housed five to a cage; cage locations in the holding rooms were randomized by computer. Animals were checked daily and all deceased animals were necropsied. WR-2721 afforded protection against both neutron- and gamma-ray-induced carcinogenesis and subsequent life shortening. Cumulative survival curves for unirradiated mice of either sex were unaffected by protectors. WR-2721 protected irradiated groups against life shortening by approximately 10 cGy of neutrons or 100 cGy of gamma rays. WR-151327 was as effective as WR-2721 against neutron irradiation.

  13. Dynamic gamma knife radiosurgery

    NASA Astrophysics Data System (ADS)

    Luan, Shuang; Swanson, Nathan; Chen, Zhe; Ma, Lijun

    2009-03-01

    Gamma knife has been the treatment of choice for various brain tumors and functional disorders. Current gamma knife radiosurgery is planned in a 'ball-packing' approach and delivered in a 'step-and-shoot' manner, i.e. it aims to 'pack' the different sized spherical high-dose volumes (called 'shots') into a tumor volume. We have developed a dynamic scheme for gamma knife radiosurgery based on the concept of 'dose-painting' to take advantage of the new robotic patient positioning system on the latest Gamma Knife C™ and Perfexion™ units. In our scheme, the spherical high dose volume created by the gamma knife unit will be viewed as a 3D spherical 'paintbrush', and treatment planning reduces to finding the best route of this 'paintbrush' to 'paint' a 3D tumor volume. Under our dose-painting concept, gamma knife radiosurgery becomes dynamic, where the patient moves continuously under the robotic positioning system. We have implemented a fully automatic dynamic gamma knife radiosurgery treatment planning system, where the inverse planning problem is solved as a traveling salesman problem combined with constrained least-square optimizations. We have also carried out experimental studies of dynamic gamma knife radiosurgery and showed the following. (1) Dynamic gamma knife radiosurgery is ideally suited for fully automatic inverse planning, where high quality radiosurgery plans can be obtained in minutes of computation. (2) Dynamic radiosurgery plans are more conformal than step-and-shoot plans and can maintain a steep dose gradient (around 13% per mm) between the target tumor volume and the surrounding critical structures. (3) It is possible to prescribe multiple isodose lines with dynamic gamma knife radiosurgery, so that the treatment can cover the periphery of the target volume while escalating the dose for high tumor burden regions. (4) With dynamic gamma knife radiosurgery, one can obtain a family of plans representing a tradeoff between the delivery time and the

  14. Gamma ray camera

    SciTech Connect

    Robbins, C.D.; Wang, S.

    1980-09-09

    An anger gamma ray camera is improved by the substitution of a gamma ray sensitive, proximity type image intensifier tube for the scintillator screen in the anger camera, the image intensifier tube having a negatively charged flat scintillator screen and a flat photocathode layer and a grounded, flat output phosphor display screen all of the same dimension (Unity image magnification) and all within a grounded metallic tube envelope and having a metallic, inwardly concaved input window between the scintillator screen and the collimator.

  15. Gamma ray optics

    SciTech Connect

    Jentschel, M.; Guenther, M. M.; Habs, D.; Thirolf, P. G.

    2012-07-09

    Via refractive or diffractive scattering one can shape {gamma} ray beams in terms of beam divergence, spot size and monochromaticity. These concepts might be particular important in combination with future highly brilliant gamma ray sources and might push the sensibility of planned experiments by several orders of magnitude. We will demonstrate the experimental feasibility of gamma ray monochromatization on a ppm level and the creation of a gamma ray beam with nanoradian divergence. The results are obtained using the inpile target position of the High Flux Reactor of the ILL Grenoble and the crystal spectrometer GAMS. Since the refractive index is believed to vanish to zero with 1/E{sup 2}, the concept of refractive optics has never been considered for gamma rays. The combination of refractive optics with monochromator crystals is proposed to be a promising design. Using the crystal spectrometer GAMS, we have measured for the first time the refractive index at energies in the energy range of 180 - 2000 keV. The results indicate a deviation from simple 1/E{sup 2} extrapolation of X-ray results towards higher energies. A first interpretation of these new results will be presented. We will discuss the consequences of these results on the construction of refractive optics such as lenses or refracting prisms for gamma rays and their combination with single crystal monochromators.

  16. Upgrading and testing the 3D reconstruction of gamma-ray air showers as observed with an array of Cherenkov telescopes

    SciTech Connect

    Naumann-Godo, Melitta; Degrange, Bernard

    2008-12-24

    Stereoscopic arrays of Imaging Cherenkov Telescopes allow to reconstruct gamma-ray-induced showers in 3 dimensions. An analysis method based on a simple 3D-model of electromagnetic showers and implemented in the framework of the H.E.S.S. experiment was recently improved by an additional quality criterion which reduces the background contamination by a factor of about 2 in the case of extended sources, while hardly affecting gamma-ray selection efficiency. Moreover, the dramatic flares of PKS 2155-304 in July 2006, which provided H.E.S.S. data with an almost pure gamma-ray sample, offered the unique opportunity of a precision test of the 3D-reconstruction method as well as of the H.E.S.S. simulations used in its calibration. An agreement at a few percent level is found between data and simulations for the distributions of all 3D shower parameters.

  17. Similarity and Reciprocity Effects on Friendship Preferences of Elementary School Children.

    ERIC Educational Resources Information Center

    Drewry, Debra L.; Clark, M. L.

    This study investigated the effect of similarity and reciprocity on dyadic friendship choices. Subjects were 34 third graders and 30 sixth graders. Reciprocal (mutual) and nonreciprocal (nonmutual) friendships were identified through use of the roster sociometric technique, whereby children choose their three best friends from an alphabetized list…

  18. 14 CFR 135.369 - Large transport category airplanes: Reciprocating engine powered: En route limitations: All...

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 3 2010-01-01 2010-01-01 false Large transport category airplanes: Reciprocating engine powered: En route limitations: All engines operating. 135.369 Section 135.369 Aeronautics... Limitations § 135.369 Large transport category airplanes: Reciprocating engine powered: En route...

  19. 14 CFR 121.181 - Airplanes: Reciprocating engine-powered: En route limitations: One engine inoperative.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 3 2010-01-01 2010-01-01 false Airplanes: Reciprocating engine-powered: En route limitations: One engine inoperative. 121.181 Section 121.181 Aeronautics and Space FEDERAL... OPERATIONS Airplane Performance Operating Limitations § 121.181 Airplanes: Reciprocating engine-powered:...

  20. 14 CFR 121.179 - Airplanes: Reciprocating engine-powered: En route limitations: All engines operating.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 3 2010-01-01 2010-01-01 false Airplanes: Reciprocating engine-powered: En route limitations: All engines operating. 121.179 Section 121.179 Aeronautics and Space FEDERAL AVIATION... Performance Operating Limitations § 121.179 Airplanes: Reciprocating engine-powered: En route limitations:...