Science.gov

Sample records for predominantly bimodal hybridizing

  1. Investigating temporal changes in hybridization and introgression in a predominantly bimodal hybridizing population of invasive sika (Cervus nippon) and native red deer (C. elaphus) on the Kintyre Peninsula, Scotland.

    PubMed

    Senn, H V; Barton, N H; Goodman, S J; Swanson, G M; Abernethy, K A; Pemberton, J M

    2010-03-01

    We investigated temporal changes in hybridization and introgression between native red deer (Cervus elaphus) and invasive Japanese sika (Cervus nippon) on the Kintyre Peninsula, Scotland, over 15 years, through analysis of 1513 samples of deer at 20 microsatellite loci and a mtDNA marker. We found no evidence that either the proportion of recent hybrids, or the levels of introgression had changed over the study period. Nevertheless, in one population where the two species have been in contact since approximately 1970, 44% of individuals sampled during the study were hybrids. This suggests that hybridization between these species can proceed fairly rapidly. By analysing the number of alleles that have introgressed from polymorphic red deer into the genetically homogenous sika population, we reconstructed the haplotypes of red deer alleles introduced by backcrossing. Five separate hybridization events could account for all the recently hybridized sika-like individuals found across a large section of the Peninsula. Although we demonstrate that low rates of F1 hybridization can lead to substantial introgression, the progress of hybridization and introgression appears to be unpredictable over the short timescales.

  2. Evidence for a bimodal distribution of hybrid indices in a hybrid zone with high admixture

    PubMed Central

    McKenzie, Jessica L.; Dhillon, Rashpal S.; Schulte, Patricia M.

    2015-01-01

    The genetic structure of a hybrid zone can provide insights into the relative roles of the various factors that maintain the zone. Here, we use a multilocus approach to characterize a hybrid zone between two subspecies of killifish (Fundulus heteroclitus, Walbaum 1792) found along the Atlantic coast of North America. We first analysed clinal variation along the Atlantic coast using a single-nucleotide polymorphism in the mitochondrial DNA (mtDNA) displacement loop (D-loop) and a panel of nine nuclear microsatellite markers. A model constraining all clines to the same width and centre was not significantly different from a model in which the clines were allowed to vary independently. Locus-by-locus analysis indicated that the majority of nuclear clines shared the same centre as the mtDNA cline, and the widths of these clines were also narrower than that predicted by a neutral model, suggesting that selection is operating to maintain the hybrid zone. However, two of the nuclear clines had widths greater than the neutral prediction and had centres that were displaced relative to the mtDNA cline centre. We also found that a marsh located near the centre of the mtDNA cline demonstrated a bimodal distribution of nuclear hybrid index values, suggesting a deficit of first-generation hybrids and backcrossed genotypes. Thus, selection against hybrid genotypes may be playing a role in maintaining this hybrid zone and the associated steep nuclear and mtDNA clines. PMID:27019720

  3. Bimodal spectrum for the curvature fluctuations of bilayer vesicles: pure bending plus hybrid curvature-dilation modes.

    PubMed

    Rodríguez-García, R; Arriaga, L R; Mell, M; Moleiro, L H; López-Montero, I; Monroy, F

    2009-03-27

    We study thermal undulations of giant bilayer vesicles by flickering spectroscopy. The experimental fluctuation spectra are scrutinized in view of the classical Helfrich theory. Pure bending modes are revealed to be unable to predict the large fluctuations systematically found at a high wave vector. Hybrid curvature-dilational modes are then invoked as a more efficient mode of motion in producing high curvatures. A bimodal spectrum of the thermal undulations has been theoretically developed for the shell-like topology. Reconciliation between experiments and theory is achieved when this bimodal spectrum is considered.

  4. A Crewed Mission to Apophis Using a Hybrid Bimodal Nuclear Thermal Electric Propulsion (BNTEP) System

    NASA Technical Reports Server (NTRS)

    Mccurdy, David R.; Borowski, Stanley K.; Burke, Laura M.; Packard, Thomas W.

    2014-01-01

    A BNTEP system is a dual propellant, hybrid propulsion concept that utilizes Bimodal Nuclear Thermal Rocket (BNTR) propulsion during high thrust operations, providing 10's of kilo-Newtons of thrust per engine at a high specific impulse (Isp) of 900 s, and an Electric Propulsion (EP) system during low thrust operations at even higher Isp of around 3000 s. Electrical power for the EP system is provided by the BNTR engines in combination with a Brayton Power Conversion (BPC) closed loop system, which can provide electrical power on the order of 100's of kWe. High thrust BNTR operation uses liquid hydrogen (LH2) as reactor coolant propellant expelled out a nozzle, while low thrust EP uses high pressure xenon expelled by an electric grid. By utilizing an optimized combination of low and high thrust propulsion, significant mass savings over a conventional NTR vehicle can be realized. Low thrust mission events, such as midcourse corrections (MCC), tank settling burns, some reaction control system (RCS) burns, and even a small portion at the end of the departure burn can be performed with EP. Crewed and robotic deep space missions to a near Earth asteroid (NEA) are best suited for this hybrid propulsion approach. For these mission scenarios, the Earth return V is typically small enough that EP alone is sufficient. A crewed mission to the NEA Apophis in the year 2028 with an expendable BNTEP transfer vehicle is presented. Assembly operations, launch element masses, and other key characteristics of the vehicle are described. A comparison with a conventional NTR vehicle performing the same mission is also provided. Finally, reusability of the BNTEP transfer vehicle is explored.

  5. Habitat Association and Seasonality in a Mosaic and Bimodal Hybrid Zone between Chorthippus brunneus and C. jacobsi (Orthoptera: Acrididae)

    PubMed Central

    Tatsuta, Haruki; Butlin, Roger K.

    2012-01-01

    Understanding why some hybrid zones are bimodal and others unimodal can aid in identifying barriers to gene exchange following secondary contact. The hybrid zone between the grasshoppers Chorthippus brunneus and C. jacobsi contains a mix of allopatric parental populations and inter-mingled bimodal and unimodal sympatric populations, and provides an ideal system to examine the roles of local selection and gene flow between populations in maintaining bimodality. However, it is first necessary to confirm, over a larger spatial scale, previously identified associations between population composition and season and habitat. Here we use cline-fitting of one morphological and one song trait along two valley transects, and intervening mountains, to confirm previously identified habitat associations (mountain versus valley) and seasonal changes in population composition. As expected from previous findings of studies on a smaller spatial scale, C. jacobsi dominated mountain habitats and mixed populations dominated valleys, and C. brunneus became more prevalent in August. Controlling for habitat and incorporating into the analysis seasonal changes in cline parameters and the standard errors of parental trait values revealed wider clines than previous studies (best estimates of 6.4 to 24.5 km in our study versus 2.8 to 4.7 km in previous studies) and increased percentage of trait variance explained (52.7% and 61.5% for transects 1 and 2 respectively, versus 17.6%). Revealing such strong and consistent patterns within a complex hybrid zone will allow more focused examination of the causes of variation in bimodality in mixed populations, in particular the roles of local selection versus habitat heterogeneity and gene flow between differentiated populations. PMID:22675485

  6. Bimodal distribution of flowering time in a natural hybrid population of daylily (Hemerocallis fulva) and nightlily (Hemerocallis citrina).

    PubMed

    Hasegawa, Masahiro; Yahara, Tetsukazu; Yasumoto, Akiko; Hotta, Mitsuru

    2006-01-01

    Time of flower anthesis in a day is thought to evolve in response to the time of pollinator activities. We studied blooming and withering time in natural populations of daylily (Hemerocallis fulva), nightlily (Hemerocallis citrina) and their hybrids, and also in an artificially obtained array of the F1 hybrids. Blooming time of H. fulva varied from 4:30 to 7:30 and H. citrina varied from 16:30 to 20:30. In a natural hybrid population, blooming time and withering time showed discontinuous bimodal distribution in spite that morphological traits of flowers showed continuous unimodal variation. Most F1 hybrids showed diurnal flowering. These findings indicate that only a few genes have strong phenotypic effect on the determination of flowering time in Hemerocallis, and suggest that the evolution from a H. fulva-like ancestor to H. citrina was not a continuous process by accumulation of minute mutations.

  7. Bimodal fission

    SciTech Connect

    Hulet, E.K.

    1989-04-19

    In recent years, we have measured the mass and kinetic-energy distributions from the spontaneous fission of /sup 258/Fm, /sup 259/Md, /sup 260/Md, /sup 258/No, /sup 262/No, and /sup 260/(104). All are observed to fission with a symmetrical division of mass, whereas the total-kinetic-energy (TKE) distributions strongly deviated from the Gaussian shape characteristically found in the fission of all other actinides. When the TKE distributions are resolved into two Gaussians the constituent peaks lie near 200 and near 233 MeV. We conclude two modes or bimodal fission is occurring in five of the six nuclides studied. Both modes are possible in the same nuclides, but one generally predominates. We also conclude the low-energy but mass-symmetrical mode is likely to extend to far heavier nuclei; while the high-energy mode will be restricted to a smaller region, a region of nuclei defined by the proximity of the fragments to the strong neutron and proton shells in /sup 132/Sn. 16 refs., 7 figs., 1 tab.

  8. Transvaginal postpartum manual removal of a prolapsed submucous leiomyoma, initially diagnosed hybrid predominantly intramural.

    PubMed

    Elgonaid, Wael; Belkhir, Reem; Boama, Vincent

    2017-08-11

    We present a rare case of a large infarcted submucous fibroid removed manually after a normal vaginal delivery. This patient was known to have a large postero-fundal hybrid predominantly intramural uterine fibroid, measuring 11 x 10 cm in diameter and diagnosed 2 years prior to last conception. Thirty-five days postpartum, she presented with severe lower abdominal pain and foul smell per vaginum. Abdominal examination revealed a very tender bulky uterus at 24 weeks size, and vaginal examination revealed a big fleshy smelly mass with friable surface just bulging from a dilated cervix. Examination under anaesthesia revealed a very foul smelly large pedunculated submucous fibroid that was felt through a dilated cervix. It was deliverable vaginally, so the submucous leiomyoma was removed manually, a procedure similar to manual removal of placenta. Histopathology examination confirmed an infarcted massive fibroid. © BMJ Publishing Group Ltd (unless otherwise stated in the text of the article) 2017. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

  9. Bimodal Bilingualism

    ERIC Educational Resources Information Center

    Emmorey, Karen; Borinstein, Helsa B.; Thompson, Robin; Gollan, Tamar H.

    2008-01-01

    Speech-sign or "bimodal" bilingualism is exceptional because distinct modalities allow for simultaneous production of two languages. We investigated the ramifications of this phenomenon for models of language production by eliciting language mixing from eleven hearing native users of American Sign Language (ASL) and English. Instead of switching…

  10. Hybrid propulsion systems for motor vehicles with predominantly intermittent modes of operation

    NASA Technical Reports Server (NTRS)

    Bartsch, H.; Helling, J.; Schreck, H.

    1977-01-01

    A small delivery vehicle was equipped with a flywheel-hybrid drive and compared in test stand and driving tests with a conventional drive vehicle. It turned out that with the hybrid drive, energy can be saved and exhaust emissions can be reduced.

  11. Predominant Expression of Hybrid N-Glycans Has Distinct Cellular Roles Relative to Complex and Oligomannose N-Glycans

    PubMed Central

    Hall, M. Kristen; Weidner, Douglas A.; Zhu, Yong; Dayal, Sahil; Whitman, Austin A.; Schwalbe, Ruth A.

    2016-01-01

    Glycosylation modulates growth, maintenance, and stress signaling processes. Consequently, altered N-glycosylation is associated with reduced fitness and disease. Therefore, expanding our understanding of N-glycans in altering biological processes is of utmost interest. Herein, clustered regularly interspaced short palindromic repeats/caspase9 (CRISPR/Cas9) technology was employed to engineer a glycosylation mutant Chinese Hamster Ovary (CHO) cell line, K16, which expresses predominantly hybrid type N-glycans. This newly engineered cell line enabled us to compare N-glycan effects on cellular properties of hybrid type N-glycans, to the well-established Pro−5 and Lec1 cell lines, which express complex and oligomannose types of N-glycans, respectively. Lectin binding studies revealed the predominant N-glycan expressed in K16 is hybrid type. Cell dissociation and migration assays demonstrated the greatest strength of cell–cell adhesion and fastest migratory rates for oligomannose N-glycans, and these properties decreased as oligomannose type were converted to hybrid type, and further decreased upon conversion to complex type. Next, we examined the roles of three general types of N-glycans on ectopic expression of E-cadherin, a cell–cell adhesion protein. Microscopy revealed more functional E-cadherin at the cell–cell border when N-glycans were oligomannose and these levels decreased as the oligomannose N-glycans were processed to hybrid and then to complex. Thus, we provide evidence that all three general types of N-glycans impact plasma membrane architecture and cellular properties. PMID:27304954

  12. Initiation of programmed cell death in the suspensor is predominantly regulated maternally in a tobacco hybrid.

    PubMed

    Luo, An; Zhao, Peng; Zhang, Li-Yao; Sun, Meng-Xiang

    2016-07-19

    Maternal gene products deposited in the egg regulate early embryogenesis before activation of the embryonic genome in animals. While in higher plants, it is believed that genes of parental origin contribute to early embryogenesis. However, little is known regarding the particular processes in which genes of parental origin are involved during early embryogenesis. Previously, we found that the initiation of programmed cell death (PCD) in the suspensor of the embryo is regulated by the cystatin, NtCYS. Here, we confirmed that both parental transcripts contribute to PCD, but the relative expression level of the maternal NtCYS allele was much higher than that of the paternal allele in early embryos of tobacco interspecific hybrids. The expression level of the maternal NtCYS allele was decreased markedly, which was necessary for the initiation of PCD, while the paternal allele didn't change. Interestingly, the pattern of PCD in the hybrid suspensor and the morphology of the hybrid suspensor were similar to those of the maternal parent. Our results suggest that NtCYS-mediated PCD initiation in the hybrid suspensor is likely controlled in a maternal dominant manner. This finding represents an example of the involvement of parental transcripts in a specific developmental event during early embryogenesis.

  13. Bimodal-hybrid heterocyclic amine targeting oxidative pathways and copper mis-regulation in Alzheimer’s disease

    PubMed Central

    Gonzalez, Paulina; da Costa, Viviana C.P.; Hyde, Kimberly; Wu, Qiong; Annunziata, Onofrio; Rizo, Josep; Akkaraju, Giridhar; Green, Kayla N.

    2014-01-01

    Oxidative stress resulting from metal-ion misregulation plays a role in the development of Alzheimer’s disease (AD). This process includes the production of tissue-damaging reactive oxygen species and amyloid aggregates. Herein we describe the synthesis, characterization and protective capacity of the small molecule, lipoic cyclen, which has been designed to target molecular features of AD. This construct utilizes the biologically compatible and naturally occurring lipoic acid as a foundation for engendering low cellular toxicity in multiple cell lines, radical scavenging capacity, tuning the metal affinity of the parent cyclen, and results in an unexpected affinity for amyloid without inducing aggregation. The hybrid construct thereby shows protection against cell death induced by amyloid aggregates and copper ions. These results provide evidence for the rational design methods used to produce this fused molecule as a potential strategy for the development of lead compounds for the treatment of neurodegenerative disorders. PMID:25144522

  14. The characteristics of novel bimodal Ag-TiO2 nanoparticles generated by hybrid laser-ultrasonic technique

    NASA Astrophysics Data System (ADS)

    Hamad, Abubaker; Li, Lin; Liu, Zhu; Zhong, Xiang Li; Burke, Grace; Wang, Tao

    2016-04-01

    Silver-titania (Ag-TiO2) nanoparticles with smaller Ag nanoparticles attached to larger TiO2 nanoparticles were generated by hybrid ultrasonic vibration and picosecond laser ablation of Ag and Ti bulk targets in deionised water, for the first time. The laser has a wavelength of 1064 nm and a pulse duration of 10 ps. It was observed that without the ultrasonic vibration, Ag and TiO2 nanoparticles did not combine, thus the role of ultrasonic vibration is essential. In addition, colloidal TiO2 and Ag nanoparticles were generated separately for comparison under the same laser beam characteristics and process conditions. The absorption spectra of colloidal Ag-TiO2 cluster nanoparticles were examined by UV-Vis spectroscopy, and size distribution was characterised using transmission electron microscopy. The morphology and composition of Ag-TiO2 nanoparticles were examined using scanning transmission electron microscopy in high-angle annular dark field, and energy-dispersive X-ray spectroscopy. The crystalline structures were investigated by X-ray diffraction. The size of larger TiO2 particles was in the range 30-150 nm, and the smaller-sized Ag nanoparticles attached to the TiO2 was mainly in the range of 10-15 nm. The yield is more than 50 % with the remaining nanoparticles in the form of uncombined Ag and TiO2. The nanoparticles generated had strong antibacterial effects as tested against E. coli. A discussion is given on the role of ultrasonic vibration in the formation of Ag-TiO2 hybrid nanoparticles by picosecond laser ablation.

  15. Paper analytical devices for dynamic evaluation of cell surface N-glycan expression via a bimodal biosensor based on multibranched hybridization chain reaction amplification.

    PubMed

    Liang, Linlin; Lan, Feifei; Li, Li; Ge, Shenguang; Yu, Jinghua; Ren, Na; Liu, Haiyun; Yan, Mei

    2016-12-15

    A novel colorimetric/fluorescence bimodal lab-on-paper cyto-device was fabricated based on concanavalin A (Con A)-integrating multibranched hybridization chain reaction (mHCR). The product of mHCR was modified PtCu nanochains (colorimetric signal label) and graphene quantum dot (fluorescence signal label) for in situ and dynamically evaluating cell surface N-glycan expression. In this strategy, preliminary detection was carried out through colorimetric method, if needed, then the fluorescence method was applied for a precise determination. Au-Ag-paper devices increased the surface areas and active sites for immobilizing larger amount of aptamers, and then specifically and efficiently captured more cancer cells. Moreover, it could effectively reduce the paper background fluorescence. Due to the specific recognition of Con A with mannose and the effective signal amplification of mHCR, the proposed strategy exhibited excellent high sensitivity for the cytosensing of MCF-7 cells ranging from 100 to 1.0×10(7) and 80-5.0×10(7) cellsmL(-1) with the detection limit of 33 and 26 cellsmL(-1) for colorimetric and fluorescence, respectively. More importantly, this strategy was successfully applied to dynamically monitor cell-surface multi-glycans expression on living cells under external stimuli of inhibitors as well as for N-glycan expression inhibitor screening. These results implied that this biosensor has potential in studying complex native glycan-related biological processes and elucidating the N-glycan-related diseases in biological and physiological processes.

  16. Bimodal Active Nuclei in Bimodal Galaxies

    NASA Astrophysics Data System (ADS)

    Cavaliere, A.; Menci, N.

    2007-07-01

    By their star content, the galaxies split out into a red and a blue population; their color index peaked around u-r~2.5 or u-r~1, respectively, quantifies the ratio of the blue stars newly formed from cold galactic gas, to the redder ones left over by past generations. On the other hand, on accreting substantial gas amounts the central massive black holes energize active galactic nuclei (AGNs); here we investigate whether these show a similar, and possibly related, bimodal partition as for current accretion activity relative to the past. To this aim we use an updated semianalytic model; based on Monte Carlo simulations, this follows with a large statistics the galaxy assemblage, the star generations, and the black hole accretions in the cosmological framework over the redshift span from z=10 to z=0. We test our simulations for yielding in close detail the observed split of galaxies into a red, early and a blue, late population. We find that the black hole accretion activities likewise give rise to two source populations: early, bright quasars and later, dimmer AGNs. We predict for their Eddington parameter λE-the ratio of the current to the past black hole accretions-a bimodal distribution; the two branches sit now under λE~0.01 (mainly contributed by low-luminosity AGNs) and around λE~0.3-1. These not only mark out the two populations of AGNs, but also will turn out to correlate strongly with the red or blue color of their host galaxies.

  17. Distinctiveness in the face of gene flow: hybridization between specialist and generalist gartersnakes.

    PubMed

    Fitzpatrick, Benjamin M; Placyk, John S; Niemiller, Matthew L; Casper, Gary S; Burghardt, Gordon M

    2008-09-01

    Patterns of divergence and polymorphism across hybrid zones can provide important clues as to their origin and maintenance. Unimodal hybrid zones or hybrid swarms are composed predominantly of recombinant individuals whose genomes are patchworks of alleles derived from each parental lineage. In contrast, bimodal hybrid zones contain few identifiable hybrids; most individuals fall within distinct genetic clusters. Distinguishing between hybrid swarms and bimodal hybrid zones can be important for taxonomic and conservation decisions regarding the status and value of hybrid populations. In addition, the causes of bimodality are important in understanding the generation and maintenance of biological diversity. For example, are distinct clusters mostly reproductively isolated and co-adapted gene complexes, or can distinctiveness be maintained by a few 'genomic islands' despite rampant gene flow across much of the genome? Here we focus on three patterns of distinctiveness in the face of gene flow between gartersnake taxa in the Great Lakes region of North America. Bimodality, the persistence of distinct clusters of genotypes, requires strong barriers to gene flow and supports recognition of distinct specialist (Thamnophis butleri) and generalist (Thamnophis radix) taxa. Concordance of DNA-based clusters with morphometrics supports the hypothesis that trophic morphology is a key component of divergence. Finally, disparity in the level of differentiation across molecular markers (amplified fragment length polymorphisms) indicates that distinctiveness is maintained by strong selection on a few traits despite high gene flow currently or in the recent past.

  18. Bimodal fission of Hs*

    NASA Astrophysics Data System (ADS)

    Itkis, I. M.; Itkis, M. G.; Knyazheva, G. N.; Kozulin, E. M.; Loktev, T. A.; Novikov, K. V.; Hanappe, F.; Vardaci, E.

    2014-05-01

    Mass and energy distributions of fission fragments obtained in the reactions 22Ne + 249Cf, 26Mg + 248Cm, and 22Ne + 238U have been measured. A special attention will be paid on the properties of mass-energy distribution of fission fragments obtained in the reaction 26Mg + 248Cm at an excitation energy of 35 MeV. At this energy shell effects should become more effective in fission, the TKE distribution of symmetric fragments obtained in the reaction 26Mg + 248Cm differs strongly from a Gaussian shape. Besides a low-energy component, a high-energy component, not foreseen in the LDM, arises. This is attributed to the fact that both fission fragments are close to the spherical neutron shell N = 82. It means that for the compound nucleus 274Hs*, formed in the reaction 26Mg + 248Cm, the phenomenon of bimodal fission was observed for the first time. For the compound nucleus 260No* formed in the reaction 22Ne + 238U at the initial excitation energy of 41 MeV the bimodal fission as well as superasymmetric fission were observed.

  19. Array comparative genomic hybridization reveals similarities between nodular lymphocyte predominant Hodgkin lymphoma and T cell/histiocyte rich large B cell lymphoma.

    PubMed

    Hartmann, Sylvia; Döring, Claudia; Vucic, Emily; Chan, Fong Chun; Ennishi, Daisuke; Tousseyn, Thomas; de Wolf-Peeters, Christiane; Perner, Sven; Wlodarska, Iwona; Steidl, Christian; Gascoyne, Randy D; Hansmann, Martin-Leo

    2015-05-01

    Nodular lymphocyte predominant Hodgkin lymphoma (NLPHL) and T cell/histiocyte rich large B cell lymphoma (THRLBCL) usually affect middle-aged men, show tumour cells with a B cell phenotype and a low tumour cell content. Whereas the clinical behaviour of NLPHL is indolent, THRLBCL presents with advanced stage disease and an aggressive behaviour. In the present study, array comparative genomic hybridization was performed in seven typical NLPHL, four THRLBCL-like NLPHL variants, six THRLBCL and four diffuse large B cell lymphomas (DLBCL) derived from NLPHL. The number of genomic aberrations was higher in THRLBCL compared with typical and THRLBCL-like variant of NLPHL. Gains of 2p16.1 and losses of 2p11.2 and 9p11.2 were commonly observed in typical and THRLBCL-like variants of NLPHL as well as THRLBCL. Gains of 2p16.1, affecting the REL locus were confirmed in an independent cohort. Expression of the REL protein was observed at similar frequencies in typical and THRLBCL-like variant of NLPHL as well as THRLBCL (33-38%). In conclusion, the present study reveals further similarities between NLPHL and THRLBCL on the genomic level, confirming that these entities are part of a pathobiological spectrum with common molecular features, but varying clinical presentations. © 2015 John Wiley & Sons Ltd.

  20. Bimodal Technology Readiness Assessment

    NASA Astrophysics Data System (ADS)

    Buden, David; Schuller, Michael; Kennedy, Fred; Dibben, Mark; Baker, Eric; Vanek, Vlad

    1994-07-01

    Phillips Laboratory is evaluating Bimodal nuclear reactor power plants that can perform both power and nuclear thermal propulsion functions for a space vehicle. The objectives are to decrease Air Force mission costs, enhance mission capabilities, and enable new missions. Minimizing development costs and schedules by building on previous space nuclear power plant investments will be a major consideration in formulating concepts. Therefore, a data base that summarizes the technology status of possible components has been prepared and is being constantly expanded. Use is made of the NASA technology definitions. The results of this assessment of particular elements of space nuclear power will be discussed. It shows that existing components could be used for a one 1.5 y flight demonstration that have been breadboards in a laboratory environment or qualified for flight. For a 5 y Initial Operation Capability, significant component qualification is needed. However, all necessary components can be classified as development items.

  1. Oculomotor interference of bimodal distractors.

    PubMed

    Heeman, Jessica; Nijboer, Tanja C W; Van der Stoep, Nathan; Theeuwes, Jan; Van der Stigchel, Stefan

    2016-06-01

    When executing an eye movement to a target location, the presence of an irrelevant distracting stimulus can influence the saccade metrics and latency. The present study investigated the influence of distractors of different sensory modalities (i.e. auditory, visual and audiovisual) which were presented at various distances (i.e. close or remote) from a visual target. The interfering effects of a bimodal distractor were more pronounced in the spatial domain than in the temporal domain. The results indicate that the direction of interference depended on the spatial layout of the visual scene. The close bimodal distractor caused the saccade endpoint and saccade trajectory to deviate towards the distractor whereas the remote bimodal distractor caused a deviation away from the distractor. Furthermore, saccade averaging and trajectory deviation evoked by a bimodal distractor was larger compared to the effects evoked by a unimodal distractor. This indicates that a bimodal distractor evoked stronger spatial oculomotor competition compared to a unimodal distractor and that the direction of the interference depended on the distance between the target and the distractor. Together, these findings suggest that the oculomotor vector to irrelevant bimodal input is enhanced and that the interference by multisensory input is stronger compared to unisensory input.

  2. Nonlinear dynamics of bimodality in vehicular traffic

    NASA Astrophysics Data System (ADS)

    Mullick, Arjun; Ray, Arnab K.

    2016-10-01

    We provide a global model for the bimodal distribution of a one-dimensional vehicular traffic flow. Our model captures the essential features of bimodality, namely, asymptotically decaying tails, asymmetry of the bimodal peaks, and their oscillatory exhange in a twenty-four cyle of traffic flows. We analyse our model from the perspective of nonlinear dynamics, and show that in a phase portrait, bimodality is implied by fixed points, closed loops, local periodicity and homoclinic paths. We also find the conditions for the asymmetry in a bimodal function, and for a bimodal-to-unimodal transition.

  3. Event-related potentials to visual, auditory, and bimodal (combined auditory-visual) stimuli.

    PubMed

    Isoğlu-Alkaç, Ummühan; Kedzior, Karina; Keskindemirci, Gonca; Ermutlu, Numan; Karamursel, Sacit

    2007-02-01

    The purpose of this study was to investigate the response properties of event related potentials to unimodal and bimodal stimulations. The amplitudes of N1 and P2 were larger during bimodal evoked potentials (BEPs) than auditory evoked potentials (AEPs) in the anterior sites and the amplitudes of P1 were larger during BEPs than VEPs especially at the parieto-occipital locations. Responses to bimodal stimulation had longer latencies than responses to unimodal stimulation. The N1 and P2 components were larger in amplitude and longer in latency during the bimodal paradigm and predominantly occurred at the anterior sites. Therefore, the current bimodal paradigm can be used to investigate the involvement and location of specific neural generators that contribute to higher processing of sensory information. Moreover, this paradigm may be a useful tool to investigate the level of sensory dysfunctions in clinical samples.

  4. Entangled light from bimodal optical nanoantennas

    NASA Astrophysics Data System (ADS)

    Straubel, J.; Sarniak, R.; Rockstuhl, C.; Słowik, K.

    2017-02-01

    We suggest a hybrid plasmonic device made of a bimodal metallic nanoantenna coupled to an incoherently pumped quantum emitter. This device emits light into the two modes entangled in the number of photons. The process is a prime example of losses changing from being a nuisance into something beneficial, since, although it is counterintuitive, the entanglement is enabled by strong incoherent processes, i.e., the dominant scattering and absorption rates of the nanoantenna. This renders the nanoantenna an active source of nonclassicality. Both the high emission rate and the degree of entanglement of the emitted light are insensitive with respect to imperfections in the nanoantenna length, rendering the scheme feasible for an implementation.

  5. A bimodal biometric identification system

    NASA Astrophysics Data System (ADS)

    Laghari, Mohammad S.; Khuwaja, Gulzar A.

    2013-03-01

    Biometrics consists of methods for uniquely recognizing humans based upon one or more intrinsic physical or behavioral traits. Physicals are related to the shape of the body. Behavioral are related to the behavior of a person. However, biometric authentication systems suffer from imprecision and difficulty in person recognition due to a number of reasons and no single biometrics is expected to effectively satisfy the requirements of all verification and/or identification applications. Bimodal biometric systems are expected to be more reliable due to the presence of two pieces of evidence and also be able to meet the severe performance requirements imposed by various applications. This paper presents a neural network based bimodal biometric identification system by using human face and handwritten signature features.

  6. Bimodal fitting or bilateral implantation?

    PubMed

    Ching, Teresa Y C; Massie, Robyn; Van Wanrooy, Emma; Rushbrooke, Emma; Psarros, Colleen

    2009-01-01

    This paper summarises findings from studies that evaluated the benefits of bimodal fitting (combining a hearing aid and a cochlear implant in opposite ears) or bilateral cochlear implantation, relative to unilateral implantation, for children (Ching et al., 2007). On average, the size of binaural speech intelligibility advantages due to redundancy and head shadow was similar for the two bilateral conditions. An added advantage of bimodal fitting was that the low-frequency cues provided by acoustic hearing complemented the high-frequency cues conveyed by electric hearing in perception of voice and music. Some children with bilateral cochlear implants were able to use spatial separation between speech and noise to improve speech perception in noise. This is possibly a combined effect of the directional microphones in their implant systems and their ability to use spatial cues. The evidence to date supports the provision of hearing in two ears as the standard of care.

  7. Solitary Dunes under Bimodal Winds

    NASA Astrophysics Data System (ADS)

    Reffet, Erwan; Courrech du Pont, S.; Hersen, P.; Fulchignoni, M.; Douady, S.

    2009-01-01

    The high resolution and coverage achieved on Mars' surface have detailed lots of sand dunes of various types [1]. Many are reported as barchan or barchanoid dunes and present a diversity of shape ascribed to compound wind regimes, collisions or cementation. This diversity reminds us that aeolian structures are fairly complex. Although dunes have been extensively observed and documented, the conditions of their formation and evolution are still difficult to study because of the long time required for their development and their large length-scale. We developed a laboratory approach using underwater experiments to study the morphology of dunes. This method has been used successfully to reproduce various types of dunes downsized to a few centimeters. Barchan dunes are formed using a unidirectional wind-equivalent regime on a pile of ceramic sand-sized grains [2]. Changing the wind regime to a more complex one reveals other structures. In the case of multiple wind directions star dunes can be observed. A bimodal wind regime, e.g. switching between two distinct directions, over an homogeneous layer of sand leads to transverse, longitudinal or complex compound sandbeds depending on the angle between these wind directions [3]. Here, we apply bimodal wind regimes to isolated patches of sand in order to observe the variation of morphology of the resulting dunes. We present the barchanoid dunes obtained for various angles of bimodal wind and show the transition to the "chestnut” dunes type. We also investigate sudden variations in wind direction over a barchan dune. Therefore, we illustrate how the (not so) simple barchan shape can be affected by a more complex wind regime and give a new insight in understanding dunes on Mars. [1] http://www.mars-dunes.org/ . [2] Hersen et al. PRL, 2003. [3] Reffet et al. pldu.work 2008.

  8. Bimodal porous gold opals for molecular sensing

    NASA Astrophysics Data System (ADS)

    Chae, Weon-Sik; Yu, Hyunung; Ham, Sung-Kyoung; Lee, Myung-Jin; Jung, Jin-Seung; Robinson, David B.

    2013-11-01

    We have fabricated bimodal porous gold skeletons by double-templating routes using poly(styrene) colloidal opals as templates. The fabricated gold skeletons show a bimodal pore-size distribution, with small pores within spheres and large pores between spheres. The templated bimodal porous gold skeletons were applied in Raman scattering experiments to study sensing efficiency for probe molecules. We found that the bimodal porous gold skeletons showed obvious enhancement of Raman scattering signals versus that of the unimodal porous gold which only has interstitial pores of several hundred nanometers.

  9. Dune formation under bimodal winds

    PubMed Central

    Parteli, Eric J. R.; Durán, Orencio; Tsoar, Haim; Schwämmle, Veit; Herrmann, Hans J.

    2009-01-01

    The study of dune morphology represents a valuable tool in the investigation of planetary wind systems—the primary factor controlling the dune shape is the wind directionality. However, our understanding of dune formation is still limited to the simplest situation of unidirectional winds: There is no model that solves the equations of sand transport under the most common situation of seasonally varying wind directions. Here we present the calculation of sand transport under bimodal winds using a dune model that is extended to account for more than one wind direction. Our calculations show that dunes align longitudinally to the resultant wind trend if the angle θw between the wind directions is larger than 90°. Under high sand availability, linear seif dunes are obtained, the intriguing meandering shape of which is found to be controlled by the dune height and by the time the wind lasts at each one of the two wind directions. Unusual dune shapes including the “wedge dunes” observed on Mars appear within a wide spectrum of bimodal dune morphologies under low sand availability. PMID:20018703

  10. Dune formation under bimodal winds.

    PubMed

    Parteli, Eric J R; Durán, Orencio; Tsoar, Haim; Schwämmle, Veit; Herrmann, Hans J

    2009-12-29

    The study of dune morphology represents a valuable tool in the investigation of planetary wind systems--the primary factor controlling the dune shape is the wind directionality. However, our understanding of dune formation is still limited to the simplest situation of unidirectional winds: There is no model that solves the equations of sand transport under the most common situation of seasonally varying wind directions. Here we present the calculation of sand transport under bimodal winds using a dune model that is extended to account for more than one wind direction. Our calculations show that dunes align longitudinally to the resultant wind trend if the angle(w) between the wind directions is larger than 90 degrees. Under high sand availability, linear seif dunes are obtained, the intriguing meandering shape of which is found to be controlled by the dune height and by the time the wind lasts at each one of the two wind directions. Unusual dune shapes including the "wedge dunes" observed on Mars appear within a wide spectrum of bimodal dune morphologies under low sand availability.

  11. Nuclear bimodal new vision solar system missions

    SciTech Connect

    Mondt, J.F.; Zubrin, R.M.

    1996-03-01

    This paper presents an analysis of the potential mission capability using space reactor bimodal systems for planetary missions. Missions of interest include the Main belt asteroids, Jupiter, Saturn, Neptune, and Pluto. The space reactor bimodal system, defined by an Air Force study for Earth orbital missions, provides 10 kWe power, 1000 N thrust, 850 s Isp, with a 1500 kg system mass. Trajectories to the planetary destinations were examined and optimal direct and gravity assisted trajectories were selected. A conceptual design for a spacecraft using the space reactor bimodal system for propulsion and power, that is capable of performing the missions of interest, is defined. End-to-end mission conceptual designs for bimodal orbiter missions to Jupiter and Saturn are described. All missions considered use the Delta 3 class or Atlas 2AS launch vehicles. The space reactor bimodal power and propulsion system offers both; new vision {open_quote}{open_quote}constellation{close_quote}{close_quote} type missions in which the space reactor bimodal spacecraft acts as a carrier and communication spacecraft for a fleet of microspacecraft deployed at different scientific targets and; conventional missions with only a space reactor bimodal spacecraft and its science payload. {copyright} {ital 1996 American Institute of Physics.}

  12. Bimodal loop-gap resonator

    NASA Astrophysics Data System (ADS)

    Piasecki, W.; Froncisz, W.; Hyde, James S.

    1996-05-01

    A bimodal loop-gap resonator for use in electron paramagnetic resonance (EPR) spectroscopy at S band is described. It consists of two identical one-loop-one-gap resonators in coaxial juxtaposition. In one mode, the currents in the two loops are parallel and in the other antiparallel. By introducing additional capacitors between the loops, the frequencies of the two modes can be made to coincide. Details are given concerning variable coupling to each mode, tuning of the resonant frequency of one mode to that of the other, and adjustment of the isolation between modes. An equivalent circuit is given and network analysis carried out both experimentally and theoretically. EPR applications are described including (a) probing of the field distributions with DPPH, (b) continuous wave (cw) EPR with a spin-label line sample, (c) cw electron-electron double resonance (ELDOR), (d) modulation of saturation, and (e) saturation-recovery (SR) EPR. Bloch induction experiments can be performed when the sample extends half way through the structure, but microwave signals induced by Mx and My components of magnetization cancel when it extends completely through. This latter situation is particularly favorable for SR, modulation of saturation, and ELDOR experiments, which depend on observing Mz indirectly using a second weak observing microwave source.

  13. Co-speech gesture in bimodal bilinguals

    PubMed Central

    Casey, Shannon; Emmorey, Karen

    2008-01-01

    The effects of knowledge of sign language on co-speech gesture were investigated by comparing the spontaneous gestures of bimodal bilinguals (native users of American Sign Language and English; n = 13) and non-signing native English speakers (n = 12). Each participant viewed and re-told the Canary Row cartoon to a non-signer whom they did not know. Nine of the thirteen bimodal bilinguals produced at least one ASL sign, which we hypothesise resulted from a failure to inhibit ASL. Compared with non-signers, bimodal bilinguals produced more iconic gestures, fewer beat gestures, and more gestures from a character viewpoint. The gestures of bimodal bilinguals also exhibited a greater variety of handshape types and more frequent use of unmarked handshapes. We hypothesise that these semantic and form differences arise from an interaction between the ASL language production system and the co-speech gesture system. PMID:19430579

  14. Solar bimodal mission and operational analysis

    SciTech Connect

    Frye, P.; Law, G.

    1996-03-01

    Recent interest by both government and industry has prompted evaluation of a solar bimodal upper stage for propulsion/power applications in Earth orbit. The solar bimodal system provides an integral propulsion and power system for the orbit transfer and on-orbit phases of a satellite mission. This paper presents an initial systems evaluation of a solar bimodal system used to place satellite payloads for Geosynchronous Earth Orbit (GEO), High Earth Orbit (HEO-Molniya class), and Mid Earth Orbit (GPS class) missions with emphasis on the GEO mission. The analysis was performed as part of the Operational Effectiveness and Cost Comparison Study (OECS) sponsored by Phillips Laboratory (PL). The solar bimodal concept was investigated on a mission operational and performance basis for on-orbit power levels ranging from less than 1 kWe to 20 kWe. Atlas IIAS, Delta 7920, and Titan IV launch vehicles were considered for injecting the solar bimodal upper stage and payload into initial orbits ranging from Low Earth Orbit (LEO) (185{times}185 km circular) to higher apogee altitudes (185{times}18,500 km elliptical). The influences of engine thrust, power level, trip time, staging altitude, and thermal storage charge-discharge characteristics on the mission payload capability were developed. {copyright} {ital 1996 American Institute of Physics.}

  15. Bimodal Nuclear Thermal Rocket Analysis Developments

    NASA Technical Reports Server (NTRS)

    Belair, Michael; Lavelle, Thomas; Saimento, Charles; Juhasz, Albert; Stewart, Mark

    2014-01-01

    Nuclear thermal propulsion has long been considered an enabling technology for human missions to Mars and beyond. One concept of operations for these missions utilizes the nuclear reactor to generate electrical power during coast phases, known as bimodal operation. This presentation focuses on the systems modeling and analysis efforts for a NERVA derived concept. The NERVA bimodal operation derives the thermal energy from the core tie tube elements. Recent analysis has shown potential temperature distributions in the tie tube elements that may limit the thermodynamic efficiency of the closed Brayton cycle used to generate electricity with the current design. The results of this analysis are discussed as well as the potential implications to a bimodal NERVA type reactor.

  16. Language choice in bimodal bilingual development.

    PubMed

    Lillo-Martin, Diane; de Quadros, Ronice M; Chen Pichler, Deborah; Fieldsteel, Zoe

    2014-01-01

    Bilingual children develop sensitivity to the language used by their interlocutors at an early age, reflected in differential use of each language by the child depending on their interlocutor. Factors such as discourse context and relative language dominance in the community may mediate the degree of language differentiation in preschool age children. Bimodal bilingual children, acquiring both a sign language and a spoken language, have an even more complex situation. Their Deaf parents vary considerably in access to the spoken language. Furthermore, in addition to code-mixing and code-switching, they use code-blending-expressions in both speech and sign simultaneously-an option uniquely available to bimodal bilinguals. Code-blending is analogous to code-switching sociolinguistically, but is also a way to communicate without suppressing one language. For adult bimodal bilinguals, complete suppression of the non-selected language is cognitively demanding. We expect that bimodal bilingual children also find suppression difficult, and use blending rather than suppression in some contexts. We also expect relative community language dominance to be a factor in children's language choices. This study analyzes longitudinal spontaneous production data from four bimodal bilingual children and their Deaf and hearing interlocutors. Even at the earliest observations, the children produced more signed utterances with Deaf interlocutors and more speech with hearing interlocutors. However, while three of the four children produced >75% speech alone in speech target sessions, they produced <25% sign alone in sign target sessions. All four produced bimodal utterances in both, but more frequently in the sign sessions, potentially because they find suppression of the dominant language more difficult. Our results indicate that these children are sensitive to the language used by their interlocutors, while showing considerable influence from the dominant community language.

  17. Language choice in bimodal bilingual development

    PubMed Central

    Lillo-Martin, Diane; de Quadros, Ronice M.; Chen Pichler, Deborah; Fieldsteel, Zoe

    2014-01-01

    Bilingual children develop sensitivity to the language used by their interlocutors at an early age, reflected in differential use of each language by the child depending on their interlocutor. Factors such as discourse context and relative language dominance in the community may mediate the degree of language differentiation in preschool age children. Bimodal bilingual children, acquiring both a sign language and a spoken language, have an even more complex situation. Their Deaf parents vary considerably in access to the spoken language. Furthermore, in addition to code-mixing and code-switching, they use code-blending—expressions in both speech and sign simultaneously—an option uniquely available to bimodal bilinguals. Code-blending is analogous to code-switching sociolinguistically, but is also a way to communicate without suppressing one language. For adult bimodal bilinguals, complete suppression of the non-selected language is cognitively demanding. We expect that bimodal bilingual children also find suppression difficult, and use blending rather than suppression in some contexts. We also expect relative community language dominance to be a factor in children's language choices. This study analyzes longitudinal spontaneous production data from four bimodal bilingual children and their Deaf and hearing interlocutors. Even at the earliest observations, the children produced more signed utterances with Deaf interlocutors and more speech with hearing interlocutors. However, while three of the four children produced >75% speech alone in speech target sessions, they produced <25% sign alone in sign target sessions. All four produced bimodal utterances in both, but more frequently in the sign sessions, potentially because they find suppression of the dominant language more difficult. Our results indicate that these children are sensitive to the language used by their interlocutors, while showing considerable influence from the dominant community language. PMID

  18. Periodicity in bimodal atomic force microscopy

    SciTech Connect

    Lai, Chia-Yun; Santos, Sergio Chiesa, Matteo; Barcons, Victor

    2015-07-28

    Periodicity is fundamental for quantification and the application of conservation principles of many important systems. Here, we discuss periodicity in the context of bimodal atomic force microscopy (AFM). The relationship between the excited frequencies is shown to affect and control both experimental observables and the main expressions quantified via these observables, i.e., virial and energy transfer expressions, which form the basis of the bimodal AFM theory. The presence of a fundamental frequency further simplifies the theory and leads to close form solutions. Predictions are verified via numerical integration of the equation of motion and experimentally on a mica surface.

  19. Deaf Children's Bimodal Bilingualism and Education

    ERIC Educational Resources Information Center

    Swanwick, Ruth

    2016-01-01

    This paper provides an overview of the research into deaf children's bilingualism and bilingual education through a synthesis of studies published over the last 15 years. This review brings together the linguistic and pedagogical work on bimodal bilingualism to inform educational practice. The first section of the review provides a synthesis of…

  20. Deaf Children's Bimodal Bilingualism and Education

    ERIC Educational Resources Information Center

    Swanwick, Ruth

    2016-01-01

    This paper provides an overview of the research into deaf children's bilingualism and bilingual education through a synthesis of studies published over the last 15 years. This review brings together the linguistic and pedagogical work on bimodal bilingualism to inform educational practice. The first section of the review provides a synthesis of…

  1. Optimal transfers of spacecraft with bimodal propulsion

    NASA Astrophysics Data System (ADS)

    Kiforenko, B. N.; Kharitonov, A. M.

    2011-03-01

    An optimization problem for the interplanetary transfer of a spacecraft with bimodal nuclear rocket engine is formulated. The transfer trajectory combines high- and low-thrust phases. The necessary optimality conditions are analyzed. The solution for a 180-day Earth-Mars transfer is presented

  2. Generalized Hertz model for bimodal nanomechanical mapping

    PubMed Central

    Kocuń, Marta; Meinhold, Waiman; Walters, Deron; Proksch, Roger

    2016-01-01

    Summary Bimodal atomic force microscopy uses a cantilever that is simultaneously driven at two of its eigenmodes (resonant modes). Parameters associated with both resonances can be measured and used to extract quantitative nanomechanical information about the sample surface. Driving the first eigenmode at a large amplitude and a higher eigenmode at a small amplitude simultaneously provides four independent observables that are sensitive to the tip–sample nanomechanical interaction parameters. To demonstrate this, a generalized theoretical framework for extracting nanomechanical sample properties from bimodal experiments is presented based on Hertzian contact mechanics. Three modes of operation for measuring cantilever parameters are considered: amplitude, phase, and frequency modulation. The experimental equivalence of all three modes is demonstrated on measurements of the second eigenmode parameters. The contact mechanics theory is then extended to power-law tip shape geometries, which is applied to analyze the experimental data and extract a shape and size of the tip interacting with a polystyrene surface. PMID:27547614

  3. Discrete Bimodal Probes for Thrombus Imaging

    PubMed Central

    Uppal, Ritika; Ciesienski, Kate L.; Chonde, Daniel B.; Loving, Galen S.; Caravan, Peter

    2012-01-01

    Here we report a generalizable solid/solution phase strategy for the synthesis of discrete bimodal fibrin-targeted imaging probes. A fibrin-specific peptide was conjugated with two distinct imaging reporters at the C- and N-terminus. In vitro studies demonstrated retention of fibrin affinity and specificity. Imaging studies showed that these probes could detect fibrin over a wide range of probe concentrations by optical, magnetic resonance, and positron emission tomography imaging. PMID:22698259

  4. Feedback control of bimodal wake dynamics

    NASA Astrophysics Data System (ADS)

    Li, Ruiying; Barros, Diogo; Borée, Jacques; Cadot, Olivier; Noack, Bernd R.; Cordier, Laurent

    2016-10-01

    Feedback control is applied to symmetrize the bimodal dynamics of a turbulent blunt body wake. The flow is actuated with two lateral slit jets and monitored with pressure sensors at the rear surface. The physics-based controller is inferred from preliminary open-loop tests and is capable of symmetrizing the wake. A slight pressure recovery is achieved due to the net balance between the favourable effect of wake symmetrization and adverse effect of shear-layer mixing and vortex shedding amplification.

  5. BSA adsorption on bimodal PEO brushes.

    PubMed

    Bosker, W T E; Iakovlev, P A; Norde, W; Cohen Stuart, M A

    2005-06-15

    BSA adsorption onto bimodal PEO brushes at a solid surface was measured using optical reflectometry. Bimodal brushes consist of long (N=770) and short (N=48) PEO chains and were prepared on PS surfaces, applying mixtures of PS(29)-PEO(48) and PS(37)-PEO(770) block copolymers and using the Langmuir-Blodgett technique. Pi-A isotherms of (mixtures of) the block copolymers were measured to establish the brush regime. The isotherms of PS(29)-PEO(48) show hysteresis between compression and expansion cycles, indicating aggregation of the PS(29)-PEO(48) upon compression. Mixtures of PS(29)-PEO(48) and PS(37)-PEO(770) demonstrate a similar hysteresis effect, which eventually vanishes when the ratio of PS(37)-PEO(770) to PS(29)-PEO(48) is increased. The adsorption of BSA was determined at brushes for which the grafting density of the long PEO chains was varied, while the total grafting density was kept constant. BSA adsorption onto monomodal PEO(48) and PEO(770) brushes was determined for comparison. The BSA adsorption behavior of the bimodal brushes is similar to the adsorption of BSA at PEO(770) monomodal brushes. The maximum of BSA adsorption at low grafting density of PEO(770) can be explained by ternary adsorption, implying an attraction between BSA and PEO. The contribution of primary adsorption to the total adsorbed amount is negligible.

  6. Biomimetic synthesized bimodal nanoporous silica: Bimodal mesostructure formation and application for ibuprofen delivery.

    PubMed

    Li, Jing; Xu, Lu; Zheng, Nan; Wang, Hongyu; Lu, Fangzheng; Li, Sanming

    2016-01-01

    The present paper innovatively reports bimodal nanoporous silica synthesized using biomimetic method (B-BNS) with synthesized polymer (C16-L-serine) as template. Formation mechanism of B-BNS was deeply studied and exploration of its application as carrier of poorly water-soluble drug ibuprofen (IBU) was conducted. The bimodal nanopores and curved mesoscopic channels of B-BNS were achieved due to the dynamic self-assembly of C16-L-serine induced by silane coupling agent (3-aminopropyltriethoxysilane, APTES) and silica source (tetraethoxysilane, TEOS). Characterization results confirmed the successful synthesis of B-BNS, and particularly, nitrogen adsorption/desorption measurement demonstrated that B-BNS was meso-meso porous silica material. In application, B-BNS loaded IBU with high drug loading content due to its enlarged nanopores. After being loaded, IBU presented amorphous phase because nanoporous space and curved mesoscopic channels of B-BNS prevented the crystallization of IBU. In vitro release result revealed that B-BNS controlled IBU release with two release phases based on bimodal nanopores and improved dissolution in simulated gastric fluid due to crystalline conversion of IBU. It is convincible that biomimetic method provides novel theory and insight for synthesizing bimodal nanoporous silica, and unique functionalities of B-BNS as drug carrier can undoubtedly promote the application of bimodal nanoporous silica and development of pharmaceutical science. Copyright © 2015 Elsevier B.V. All rights reserved.

  7. Clonality in lymphocyte predominance Hodgkin's disease.

    PubMed

    Weiss, L M; Arber, D A; Chang, K L

    1997-01-01

    Abundant evidence has led to the clinical and biological separation of lymphocyte predominance from other types of Hodgkin's disease. However, it is still not clear whether lymphocyte predominance represents a polyclonal reactive lesion (possibly representing an abnormal immune disorder), a polyclonal or oligoclonal preneoplastic disorder or a monoclonal neoplastic disorder. The clinical and histological features are distinctive, but they do not provide clear indications of the nature of lymphocyte predominance. Some immunohistochemical and in situ hybridization studies have shown monotypic light chain restriction in the L&H cells, almost always of kappa type, implying a monoclonal process. Southern blotting studies are of limited utility, given their relatively low sensitivity and the rarity of L&H cells within involved tissues. Polymerase chain reaction studies have yielded conflicting results. Some, but not all, have demonstrated monoclonal populations in tissue extracts. Single cell PCR studies have generally not found monoclonal populations, although one case stands as an exception. Cases of large cell lymphoma complicating lymphocyte predominance have been monoclonal by polymerase chain reaction and clonospecific primers derived from these clones have demonstrated similar populations in the corresponding lymphocyte predominance tissues in some, but not all, studies.

  8. Transfer learning for bimodal biometrics recognition

    NASA Astrophysics Data System (ADS)

    Dan, Zhiping; Sun, Shuifa; Chen, Yanfei; Gan, Haitao

    2013-10-01

    Biometrics recognition aims to identify and predict new personal identities based on their existing knowledge. As the use of multiple biometric traits of the individual may enables more information to be used for recognition, it has been proved that multi-biometrics can produce higher accuracy than single biometrics. However, a common problem with traditional machine learning is that the training and test data should be in the same feature space, and have the same underlying distribution. If the distributions and features are different between training and future data, the model performance often drops. In this paper, we propose a transfer learning method for face recognition on bimodal biometrics. The training and test samples of bimodal biometric images are composed of the visible light face images and the infrared face images. Our algorithm transfers the knowledge across feature spaces, relaxing the assumption of same feature space as well as same underlying distribution by automatically learning a mapping between two different but somewhat similar face images. According to the experiments in the face images, the results show that the accuracy of face recognition has been greatly improved by the proposed method compared with the other previous methods. It demonstrates the effectiveness and robustness of our method.

  9. Bimodal schwa: Evidence from acoustic measurements

    NASA Astrophysics Data System (ADS)

    Yamane-Tanaka, Noriko; Gick, Bryan; Bird, Sonya

    2004-05-01

    The question of whether schwa is targeted or targetless has been the subject of much debate (Browman et al., 1992; Browman and Goldstein, 1995; Gick, 1999, 2002). Gick (2002) found that there is a pharyngeal constriction during schwa relative to rest position, and concluded that schwa is not targetless. This experiment further showed a ``bimodal'' pattern in schwa in a nonrhotic speaker, indicating that the subject has distinct schwas in lexical words and function words. The present study examines the existence of the ``bimodal'' pattern in schwas in nonrhotic dialects through an acoustic experiment. It is predicted that there is a significant difference in formant values between lexical schwas and function schwas. Results to date indicate a significant difference in them between schwas in lexical versus function words, both between historical schwas and those derived from final /r/ reduction. Data from several additional nonrhotic subjects will be presented. Implications for intrusive r as well as for the phonological treatment of function words will be discussed. [Work funded by NSERC and SSHRC.

  10. Penetration in bimodal, polydisperse granular material.

    PubMed

    Kouraytem, N; Thoroddsen, S T; Marston, J O

    2016-11-01

    We investigate the impact penetration of spheres into granular media which are compositions of two discrete size ranges, thus creating a polydisperse bimodal material. We examine the penetration depth as a function of the composition (volume fractions of the respective sizes) and impact speed. Penetration depths were found to vary between δ=0.5D_{0} and δ=7D_{0}, which, for mono-modal media only, could be correlated in terms of the total drop height, H=h+δ, as in previous studies, by incorporating correction factors for the packing fraction. Bimodal data can only be collapsed by deriving a critical packing fraction for each mass fraction. The data for the mixed grains exhibit a surprising lubricating effect, which was most significant when the finest grains [d_{s}∼O(30) μm] were added to the larger particles [d_{l}∼O(200-500) μm], with a size ratio, ε=d_{l}/d_{s}, larger than 3 and mass fractions over 25%, despite the increased packing fraction. We postulate that the small grains get between the large grains and reduce their intergrain friction, only when their mass fraction is sufficiently large to prevent them from simply rattling in the voids between the large particles. This is supported by our experimental observations of the largest lubrication effect produced by adding small glass beads to a bed of large sand particles with rough surfaces.

  11. Penetration in bimodal, polydisperse granular material

    NASA Astrophysics Data System (ADS)

    Kouraytem, N.; Thoroddsen, S. T.; Marston, J. O.

    2016-11-01

    We investigate the impact penetration of spheres into granular media which are compositions of two discrete size ranges, thus creating a polydisperse bimodal material. We examine the penetration depth as a function of the composition (volume fractions of the respective sizes) and impact speed. Penetration depths were found to vary between δ =0.5 D0 and δ =7 D0 , which, for mono-modal media only, could be correlated in terms of the total drop height, H =h +δ , as in previous studies, by incorporating correction factors for the packing fraction. Bimodal data can only be collapsed by deriving a critical packing fraction for each mass fraction. The data for the mixed grains exhibit a surprising lubricating effect, which was most significant when the finest grains [ds˜O (30 ) μ m ] were added to the larger particles [dl˜O (200 -500 ) μ m ] , with a size ratio, ɛ =dl/ds , larger than 3 and mass fractions over 25%, despite the increased packing fraction. We postulate that the small grains get between the large grains and reduce their intergrain friction, only when their mass fraction is sufficiently large to prevent them from simply rattling in the voids between the large particles. This is supported by our experimental observations of the largest lubrication effect produced by adding small glass beads to a bed of large sand particles with rough surfaces.

  12. Are star formation rates of galaxies bimodal?

    NASA Astrophysics Data System (ADS)

    Feldmann, Robert

    2017-09-01

    Star formation rate (SFR) distributions of galaxies are often assumed to be bimodal with modes corresponding to star-forming and quiescent galaxies, respectively. Both classes of galaxies are typically studied separately, and SFR distributions of star-forming galaxies are commonly modelled as lognormals. Using both observational data and results from numerical simulations, I argue that this division into star-forming and quiescent galaxies is unnecessary from a theoretical point of view and that the SFR distributions of the whole population can be well fitted by zero-inflated negative binomial distributions. This family of distributions has three parameters that determine the average SFR of the galaxies in the sample, the scatter relative to the star-forming sequence and the fraction of galaxies with zero SFRs, respectively. The proposed distributions naturally account for (i) the discrete nature of star formation, (ii) the presence of 'dead' galaxies with zero SFRs and (iii) asymmetric scatter. Excluding 'dead' galaxies, the distribution of log SFR is unimodal with a peak at the star-forming sequence and an extended tail towards low SFRs. However, uncertainties and biases in the SFR measurements can create the appearance of a bimodal distribution.

  13. Geochemical constraints on the bimodal origin of High Himalayan leucogranites

    NASA Astrophysics Data System (ADS)

    Guillot, S.; Le Fort, P.

    1995-06-01

    Major and trace element and Rb-Sr isotope systematics of the Manaslu leucogranite, Central Nepal, have been examined to constrain the role of mineral fractionation and fluids in peraluminous granite petrogenesis. Biotite and tourmaline are, for the most part, mutually exclusive, with a predominance of two-mica leucogranites over tourmaline leucogranites. The {87Sr }/{86Sr } initial isotopic ratios (Sr i) indicate that leucogranitic melts were derived from two different sources, the two-mica leucogranites having a metagreywacke origin (with Sr i < 0.752 and ɛNd < -15) and the tourmaline leucogranites a metapelitic one (Sr i> 0.752; ɛNd > - 15). Such a bimodal nature of the source zone does not directly influence the magmatic evolution, except that probably the higher initial boron content in the metapelitic rocks may increase the {Na 2O }/{K 2O } ratio. In contrast, the amount of water present during melting principally controls in part anatectic processes and element behaviour. Water-saturated conditions probably occured during melting of metagreywackeous rocks and favoured crystallization of two-mica leucogranites whereas water-absent conditions prevailed during melting of metapelitic layers and favoured biotite, plagioclase and monazite fractionation in the source zone and tourmaline crystallization in the leucogranite.

  14. Spontaneous fission properties of the heavy elements: Bimodal fission

    SciTech Connect

    Hulet, E.K.

    1988-11-11

    We have measured the mass and kinetic-energy distributions from the spontaneous fission of SVYFm, SVYNo, SVZMd, SWMd, SW(104), and SWSNo. All are observed to fission with a symmetrical division of mass, whereas the total-kinetic-energy (TKE) distributions strongly deviated from the Gaussian shape characteristically found in the fission of all other actinides. When the TKE distributions are resolved into two Gaussian's, the constituent peaks lie near 200 and near 233 MeV. We conclude two modes or bimodal fission is occurring in five of the six nuclides studied. Both modes are possible in the same nuclide, but one generally predominates. We also conclude the low-energy but mass-symmetrical mode is likely to extend to far heavier nuclei; while the high-energy mode will be restricted to a smaller region, a region of nuclei defined by the proximity of the fragments to the strong neutron and proton shells in TSSn. 21 refs., 7 figs., 1 tab.

  15. The Bimodal Bilingual Brain: Effects of Sign Language Experience

    ERIC Educational Resources Information Center

    Emmorey, Karen; McCullough, Stephen

    2009-01-01

    Bimodal bilinguals are hearing individuals who know both a signed and a spoken language. Effects of bimodal bilingualism on behavior and brain organization are reviewed, and an fMRI investigation of the recognition of facial expressions by ASL-English bilinguals is reported. The fMRI results reveal separate effects of sign language and spoken…

  16. The Bimodal Bilingual Brain: Effects of Sign Language Experience

    ERIC Educational Resources Information Center

    Emmorey, Karen; McCullough, Stephen

    2009-01-01

    Bimodal bilinguals are hearing individuals who know both a signed and a spoken language. Effects of bimodal bilingualism on behavior and brain organization are reviewed, and an fMRI investigation of the recognition of facial expressions by ASL-English bilinguals is reported. The fMRI results reveal separate effects of sign language and spoken…

  17. Optimization of phase contrast in bimodal amplitude modulation AFM

    PubMed Central

    Damircheli, Mehrnoosh; Payam, Amir F

    2015-01-01

    Summary Bimodal force microscopy has expanded the capabilities of atomic force microscopy (AFM) by providing high spatial resolution images, compositional contrast and quantitative mapping of material properties without compromising the data acquisition speed. In the first bimodal AFM configuration, an amplitude feedback loop keeps constant the amplitude of the first mode while the observables of the second mode have not feedback restrictions (bimodal AM). Here we study the conditions to enhance the compositional contrast in bimodal AM while imaging heterogeneous materials. The contrast has a maximum by decreasing the amplitude of the second mode. We demonstrate that the roles of the excited modes are asymmetric. The operational range of bimodal AM is maximized when the second mode is free to follow changes in the force. We also study the contrast in trimodal AFM by analyzing the kinetic energy ratios. The phase contrast improves by decreasing the energy of second mode relative to those of the first and third modes. PMID:26114079

  18. Bimodal stimulation: benefits for music perception and sound quality.

    PubMed

    Sucher, Catherine M; McDermott, Hugh J

    2009-01-01

    With recent expansions in cochlear implantation candidacy criteria, increasing numbers of implantees can exploit their remaining hearing by using bimodal stimulation (combining electrical stimulation via the implant with acoustic stimulation via hearing aids). This study examined the effect of bimodal stimulation on music perception and perceived sound quality. The perception of music and sound quality by nine post-lingually deafened adult implantees was examined in three conditions: implant alone, hearing aid alone and bimodal stimulation. On average, bimodal stimulation provided the best results for music perception and perceived sound quality when compared with results obtained with electrical stimulation alone. Thus, for implantees with usable acoustic hearing, bimodal stimulation may be advantageous when listening to music and other non-speech sounds. Copyright 2009 John Wiley & Sons, Ltd.

  19. Psycholinguistic, cognitive, and neural implications of bimodal bilingualism*

    PubMed Central

    EMMOREY, KAREN; GIEZEN, MARCEL R.; GOLLAN, TAMAR H.

    2017-01-01

    Bimodal bilinguals, fluent in a signed and a spoken language, exhibit a unique form of bilingualism because their two languages access distinct sensory-motor systems for comprehension and production. Differences between unimodal and bimodal bilinguals have implications for how the brain is organized to control, process, and represent two languages. Evidence from code-blending (simultaneous production of a word and a sign) indicates that the production system can access two lexical representations without cost, and the comprehension system must be able to simultaneously integrate lexical information from two languages. Further, evidence of cross-language activation in bimodal bilinguals indicates the necessity of links between languages at the lexical or semantic level. Finally, the bimodal bilingual brain differs from the unimodal bilingual brain with respect to the degree and extent of neural overlap for the two languages, with less overlap for bimodal bilinguals. PMID:28804269

  20. A simple theory of bimodal star formation

    NASA Technical Reports Server (NTRS)

    Wyse, Rosemary F. G.; Silk, J.

    1987-01-01

    A model of bimodal star formation is presented, wherein massive stars form in giant molecular clouds (GNC), at a rate regulated by supernovae energy feedback through the interstellar medium, the heat input also ensuring that the initial mass function (IMF) remains skewed towards massive stars. The low mass stars form at a constant rate. The formation of the GMC is governed by the dynamics of the host galaxy through the rotation curve and potential perturbations such as a spiral density wave. The characteristic masses, relative normalizations, and rates of formation of the massive and low mass modes of star formation may be tightly constrained by the requirements of the chemical evolution in the Solar Neighborhood. Good fits were obtained for the age metallicity relation and the metallicity structure of thin disk and spheroid stars only for a narrow range of these parameters.

  1. Bimodal and multimodal plant biomass particle mixtures

    DOEpatents

    Dooley, James H.

    2013-07-09

    An industrial feedstock of plant biomass particles having fibers aligned in a grain, wherein the particles are individually characterized by a length dimension (L) aligned substantially parallel to the grain, a width dimension (W) normal to L and aligned cross grain, and a height dimension (H) normal to W and L, wherein the L.times.H dimensions define a pair of substantially parallel side surfaces characterized by substantially intact longitudinally arrayed fibers, the W.times.H dimensions define a pair of substantially parallel end surfaces characterized by crosscut fibers and end checking between fibers, and the L.times.W dimensions define a pair of substantially parallel top and bottom surfaces, and wherein the particles in the feedstock are collectively characterized by having a bimodal or multimodal size distribution.

  2. Bimodal distribution of neon nanobubbles in aluminum

    SciTech Connect

    Dhaka, R. S.; Barman, S. R.

    2009-03-15

    Ne 1s core-level photoelectron spectra from Ne nanobubbles implanted in aluminum exhibit two peaks whose binding energies and relative intensities change with implantation energy, isochronal annealing, and sputtering. These changes in the core-level spectra are manifestations of the nanometer size of the bubbles since the screening of the photohole by the Al conduction electrons depends on the bubble size. Existence of a bimodal depth and size distribution of Ne nanobubbles is demonstrated in this work: smaller bubbles of about 4 A in radius are formed close to the Al(111) surface while the larger sized bubbles of 20 A in radius exist deeper below in the beneath subsurface region. A general relation between the radius of the rare-gas bubbles and their core-level binding energies is established.

  3. Sex identification in female crayfish is bimodal

    NASA Astrophysics Data System (ADS)

    Aquiloni, Laura; Massolo, Alessandro; Gherardi, Francesca

    2009-01-01

    Sex identification has been studied in several species of crustacean decapods but only seldom was the role of multimodality investigated in a systematic fashion. Here, we analyse the effect of single/combined chemical and visual stimuli on the ability of the crayfish Procambarus clarkii to identify the sex of a conspecific during mating interactions. Our results show that crayfish respond to the offered stimuli depending on their sex. While males rely on olfaction alone for sex identification, females require the combination of olfaction and vision to do so. In the latter, chemical and visual stimuli act as non-redundant signal components that possibly enhance the female ability to discriminate potential mates in the crowded social context experienced during mating period. This is one of the few clear examples in invertebrates of non-redundancy in a bimodal communication system.

  4. Multiphase flow modeling of a crude-oil spill site with a bimodal permeability distribution

    USGS Publications Warehouse

    Dillard, L.A.; Essaid, H.I.; Herkelrath, W.N.

    1997-01-01

    Fluid saturation, particle-size distribution, and porosity measurements were obtained from 269 core samples collected from six boreholes along a 90-m transect at a subregion of a crude-oil spill site, the north pool, near Bemidji, Minnesota. The oil saturation data, collected 11 years after the spill, showed an irregularly shaped oil body that appeared to be affected by sediment spatial variability. The particle-size distribution data were used to estimate the permeability (k) and retention curves for each sample. An additional 344 k estimates were obtained from samples previously collected at the north pool. The 613 k estimates were distributed bimodal log normally with the two population distributions corresponding to the two predominant lithologies: a coarse glacial outwash deposit and fine-grained interbedded lenses. A two-step geostatistical approach was used to generate a conditioned realization of k representing the bimodal heterogeneity. A cross-sectional multiphase flow model was used to simulate the flow of oil and water in the presence of air along the north pool transect for an 11-year period. The inclusion of a representation of the bimodal aquifer heterogeneity was crucial for reproduction of general features of the observed oil body. If the bimodal heterogeneity was characterized, hysteresis did not have to be incorporated into the model because a hysteretic effect was produced by the sediment spatial variability. By revising the relative permeability functional relation, an improved reproduction of the observed oil saturation distribution was achieved. The inclusion of water table fluctuations in the model did not significantly affect the simulated oil saturation distribution.

  5. Roles of factorial noise in inducing bimodal gene expression

    NASA Astrophysics Data System (ADS)

    Liu, Peijiang; Yuan, Zhanjiang; Huang, Lifang; Zhou, Tianshou

    2015-06-01

    Some gene regulatory systems can exhibit bimodal distributions of mRNA or protein although the deterministic counterparts are monostable. This noise-induced bimodality is an interesting phenomenon and has important biological implications, but it is unclear how different sources of expression noise (each source creates so-called factorial noise that is defined as a component of the total noise) contribute separately to this stochastic bimodality. Here we consider a minimal model of gene regulation, which is monostable in the deterministic case. Although simple, this system contains factorial noise of two main kinds: promoter noise due to switching between gene states and transcriptional (or translational) noise due to synthesis and degradation of mRNA (or protein). To better trace the roles of factorial noise in inducing bimodality, we also analyze two limit models, continuous and adiabatic approximations, apart from the exact model. We show that in the case of slow gene switching, the continuous model where only promoter noise is considered can exhibit bimodality; in the case of fast switching, the adiabatic model where only transcriptional or translational noise is considered can also exhibit bimodality but the exact model cannot; and in other cases, both promoter noise and transcriptional or translational noise can cooperatively induce bimodality. Since slow gene switching and large protein copy numbers are characteristics of eukaryotic cells, whereas fast gene switching and small protein copy numbers are characteristics of prokaryotic cells, we infer that eukaryotic stochastic bimodality is induced mainly by promoter noise, whereas prokaryotic stochastic bimodality is induced primarily by transcriptional or translational noise.

  6. Changing epidemiology of trauma deaths leads to a bimodal distribution

    PubMed Central

    Gunst, Mark; Ghaemmaghami, Vafa; Gruszecki, Amy; Urban, Jill; Frankel, Heidi

    2010-01-01

    Injury mortality was classically described with a trimodal distribution, with immediate deaths at the scene, early deaths due to hemorrhage, and late deaths from organ failure. We hypothesized that the development of trauma systems has improved prehospital care, early resuscitation, and critical care and altered this pattern. This population-based study of all trauma deaths in an urban county with a mature trauma system reviewed data for 678 patients (median age, 33 years; 81% male; 43% gunshot, 20% motor vehicle crashes). Deaths were classified as immediate (scene), early (in hospital, ≤4 hours from injury), or late (>4 hours after injury). Multinomial regression was used to identify independent predictors of immediate and early versus late deaths, adjusted for age, gender, race, intention, mechanism, toxicology, and cause of death. Results showed 416 (61%) immediate, 199 (29%) early, and 63 (10%) late deaths. Compared with the classical description, the percentage of immediate deaths remained unchanged, and early deaths occurred much earlier (median 52 vs 120 minutes). However, unlike the classic trimodal distribution, the late peak was greatly diminished. Intentional injuries, alcohol intoxication, asphyxia, and injuries to the head and chest were independent predictors of immediate death. Alcohol intoxication and injuries to the chest were predictors of early death, while pelvic fractures and blunt assaults were associated with late deaths. In conclusion, trauma deaths now have a predominantly bimodal distribution. Near elimination of the late peak likely represents advancements in resuscitation and critical care that have reduced organ failure. Further reductions in mortality will likely come from prevention of intentional injuries and injuries associated with alcohol intoxication. PMID:20944754

  7. Impact of Zygosity on Bimodal Phenotype Distributions.

    PubMed

    Holst-Hansen, Thomas; Abad, Elena; Muntasell, Aura; López-Botet, Miguel; Jensen, Mogens H; Trusina, Ala; Garcia-Ojalvo, Jordi

    2017-07-11

    Allele number, or zygosity, is a clear determinant of gene expression in diploid cells. However, the relationship between the number of copies of a gene and its expression can be hard to anticipate, especially when the gene in question is embedded in a regulatory circuit that contains feedback. Here, we study this question making use of the natural genetic variability of human populations, which allows us to compare the expression profiles of a receptor protein in natural killer cells among donors infected with human cytomegalovirus with one or two copies of the allele. Crucially, the distribution of gene expression in many of the donors is bimodal, which indicates the presence of a positive feedback loop somewhere in the regulatory environment of the gene. Three separate gene-circuit models differing in the location of the positive feedback loop with respect to the gene can all reproduce the homozygous data. However, when the resulting fitted models are applied to the hemizygous donors, one model (the one with the positive feedback located at the level of gene transcription) is superior in describing the experimentally observed gene-expression profile. In that way, our work shows that zygosity can help us relate the structure and function of gene regulatory networks. Copyright © 2017 Biophysical Society. Published by Elsevier Inc. All rights reserved.

  8. Galaxy bimodality versus stellar mass and environment

    NASA Astrophysics Data System (ADS)

    Baldry, I. K.; Balogh, M. L.; Bower, R. G.; Glazebrook, K.; Nichol, R. C.; Bamford, S. P.; Budavari, T.

    2006-12-01

    We analyse a z < 0.1 galaxy sample from the Sloan Digital Sky Survey focusing on the variation in the galaxy colour bimodality with stellar mass and projected neighbour density Σ, and on measurements of the galaxy stellar mass functions. The characteristic mass increases with environmental density from about 1010.6 to (Kroupa initial mass function, H0 = 70) for Σ in the range 0.1-10Mpc-2. The galaxy population naturally divides into a red and blue sequence with the locus of the sequences in colour-mass and colour-concentration indices not varying strongly with environment. The fraction of galaxies on the red sequence is determined in bins of 0.2 in logΣ and bins). The red fraction fr generally increases continuously in both Σ and such that there is a unified relation: . Two simple functions are proposed which provide good fits to the data. These data are compared with analogous quantities in semi-analytical models based on the Millennium N-body simulation: the Bower et al. and Croton et al. models that incorporate active galactic nucleus feedback. Both models predict a strong dependence of the red fraction on stellar mass and environment that is qualitatively similar to the observations. However, a quantitative comparison shows that the Bower et al. model is a significantly better match; this appears to be due to the different treatment of feedback in central galaxies.

  9. Earth storable bimodal engine, phase 1

    NASA Technical Reports Server (NTRS)

    1973-01-01

    An in-depth study of an Earth Storable Bimodal (ESB) Engine using earth storable propellants N2O/N2H4 and operating in either a monopropellant or bipropellant mode was conducted. Detailed studies were completed for both a hot-gas, regeneratively cooled thrust chamber and a ducted hot-gas, film cooled thrust chamber. Hydrazine decomposition products were used for cooling in either configuration. The various arrangements and configurations of hydrazine reactors, secondary injectors, chambers and gimbal methods were considered. The two basic materials selected for the major components were columbium alloys and L-605. The secondary injector types considered were previously demonstrated by JPL and consisted of a liquid-on-gas triplet, a liquid-on-gas doublet, and a liquid-on-gas coaxial injector. Various design tradeoffs were made with different reactor types located at: the secondary injector station, the thrust chamber throat, and the nozzle/extension interface. Associated thermal, structural, and mass analyses were completed.

  10. On the Bimodality of ENSO Cycle Extremes

    NASA Technical Reports Server (NTRS)

    Wilson, Robert M.

    2000-01-01

    On the basis of sea surface temperature in the El Nino 3.4 region (5 deg. N.,-5 deg. S., 120-170 deg. W.) during the interval of 1950-1997, Kevin Trenberth previously has identified some 16 El Nino and 10 La Nina, these 26 events representing the extremes of the quasi-periodic El Nino-Southern Oscillation (ENSO) cycle. Runs testing shows that the duration, recurrence period, and sequencing of these extremes vary randomly. Hence, the decade of the 1990's, especially for El Nino, is not significantly different from that of previous decadal epochs, at least, on the basis of the frequency of onsets of ENSO extremes. Additionally, the distribution of duration for both El Nino and La Nina looks strikingly bimodal, each consisting of two preferred modes, about 8- and 16-mo long for El Nino and about 9- and 18-mo long for La Nina, as does the distribution of the recurrence period for El Nino, consisting of two preferred modes about 21- and 50-mo long. Scatterplots of the recurrence period versus duration for El Nino are found to be statistically important, displaying preferential associations that link shorter (longer) duration with shorter (longer) recurrence periods. Because the last onset of El Nino occurred in April 1997 and the event was of longer than average duration, onset of the next anticipated El Nino is not expected until February 2000 or later.

  11. On The Bimodality of ENSO Cycle Extremes

    NASA Technical Reports Server (NTRS)

    Wilson, Robert M.

    2000-01-01

    On the basis of sea surface temperature in the El Nino 3.4 region (5N.-5S., 120-170W.) during the interval of 1950-1997, Kevin Trenberth previously has identified some 16 El Nino and 10 La Nina, these 26 events representing the extremes of the quasi-periodic El Nino-Southern Oscillation (ENSO) cycle. Runs testing shows that the duration, recurrence period, and sequencing of these extremes vary randomly. Hence, the decade of the 1990's, especially for El Nino, is not significantly different from that of previous decadal epochs, at least, on the basis of the frequency of onsets of ENSO extremes. Additionally, the distribution of duration for both El Nino and La Nina looks strikingly bimodal, each consisting of two preferred modes, about 8- and 16-months long for El Nino and about 9- and 18-months long for La Nina, as does the distribution of the recurrence period for El Nino, consisting of two preferred modes about 21- and 50- mo long. Scatterplots of the recurrence period versus duration for El Nino are found to be statistically important, displaying preferential associations that link shorter (longer) duration with shorter (longer) recurrence periods. Because the last onset of El Nino occurred in April 1997 and the event was of longer than average duration, onset of the next anticipated El Nino is not expected until February 2000 or later.

  12. Intelligent agents: adaptation of autonomous bimodal microsystems

    NASA Astrophysics Data System (ADS)

    Smith, Patrice; Terry, Theodore B.

    2014-03-01

    Autonomous bimodal microsystems exhibiting survivability behaviors and characteristics are able to adapt dynamically in any given environment. Equipped with a background blending exoskeleton it will have the capability to stealthily detect and observe a self-chosen viewing area while exercising some measurable form of selfpreservation by either flying or crawling away from a potential adversary. The robotic agent in this capacity activates a walk-fly algorithm, which uses a built in multi-sensor processing and navigation subsystem or algorithm for visual guidance and best walk-fly path trajectory to evade capture or annihilation. The research detailed in this paper describes the theoretical walk-fly algorithm, which broadens the scope of spatial and temporal learning, locomotion, and navigational performances based on optical flow signals necessary for flight dynamics and walking stabilities. By observing a fly's travel and avoidance behaviors; and, understanding the reverse bioengineering research efforts of others, we were able to conceptualize an algorithm, which works in conjunction with decisionmaking functions, sensory processing, and sensorimotor integration. Our findings suggest that this highly complex decentralized algorithm promotes inflight or terrain travel mobile stability which is highly suitable for nonaggressive micro platforms supporting search and rescue (SAR), and chemical and explosive detection (CED) purposes; a necessity in turbulent, non-violent structured or unstructured environments.

  13. Functionalized bimodal mesoporous silicas as carriers for controlled aspirin delivery

    NASA Astrophysics Data System (ADS)

    Gao, Lin; Sun, Jihong; Li, Yuzhen

    2011-08-01

    The bimodal mesoporous silica modified with 3-aminopropyltriethoxysilane was performed as the aspirin carrier. The samples' structure, drug loading and release profiles were characterized with X-ray diffraction, scanning electron microscopy, N 2 adsorption and desorption, Fourier transform infrared spectroscopy, TG analysis, elemental analysis and UV-spectrophotometer. For further exploring the effects of the bimodal mesopores on the drug delivery behavior, the unimodal mesoporous material MCM-41 was also modified as the aspirin carrier. Meantime, Korsmeyer-Peppas equation ft= ktn was employed to analyze the dissolution data in details. It is indicated that the bimodal mesopores are beneficial for unrestricted drug molecules diffusing and therefore lead to a higher loading and faster releasing than that of MCM-41. The results show that the aspirin delivery properties are influenced considerably by the mesoporous matrix, whereas the large pore of bimodal mesoporous silica is the key point for the improved controlled-release properties.

  14. Bimodal magmatism produced by progressively inhibited crustal assimilation.

    PubMed

    Meade, F C; Troll, V R; Ellam, R M; Freda, C; Font, L; Donaldson, C H; Klonowska, I

    2014-06-20

    The origin of bimodal (mafic-felsic) rock suites is a fundamental question in volcanology. Here we use major and trace elements, high-resolution Sr, Nd and Pb isotope analyses, experimental petrology and thermodynamic modelling to investigate bimodal magmatism at the iconic Carlingford Igneous Centre, Ireland. We show that early microgranites are the result of extensive assimilation of trace element-enriched partial melts of local metasiltstones into mafic parent magmas. Melting experiments reveal the crust is very fusible, but thermodynamic modelling indicates repeated heating events rapidly lower its melt-production capacity. Granite generation ceased once enriched partial melts could no longer form and subsequent magmatism incorporated less fertile restite compositions only, producing mafic intrusions and a pronounced compositional gap. Considering the frequency of bimodal magma suites in the North Atlantic Igneous Province, and the ubiquity of suitable crustal compositions, we propose 'progressively inhibited crustal assimilation' (PICA) as a major cause of bimodality in continental volcanism.

  15. Bimodal magmatism produced by progressively inhibited crustal assimilation

    NASA Astrophysics Data System (ADS)

    Meade, F. C.; Troll, V. R.; Ellam, R. M.; Freda, C.; Font, L.; Donaldson, C. H.; Klonowska, I.

    2014-06-01

    The origin of bimodal (mafic-felsic) rock suites is a fundamental question in volcanology. Here we use major and trace elements, high-resolution Sr, Nd and Pb isotope analyses, experimental petrology and thermodynamic modelling to investigate bimodal magmatism at the iconic Carlingford Igneous Centre, Ireland. We show that early microgranites are the result of extensive assimilation of trace element-enriched partial melts of local metasiltstones into mafic parent magmas. Melting experiments reveal the crust is very fusible, but thermodynamic modelling indicates repeated heating events rapidly lower its melt-production capacity. Granite generation ceased once enriched partial melts could no longer form and subsequent magmatism incorporated less fertile restite compositions only, producing mafic intrusions and a pronounced compositional gap. Considering the frequency of bimodal magma suites in the North Atlantic Igneous Province, and the ubiquity of suitable crustal compositions, we propose ‘progressively inhibited crustal assimilation’ (PICA) as a major cause of bimodality in continental volcanism.

  16. Bimodal Programming: A Survey of Current Clinical Practice.

    PubMed

    Siburt, Hannah W; Holmes, Alice E

    2015-06-01

    The purpose of this study was to determine the current clinical practice in approaches to bimodal programming in the United States. To be specific, if clinicians are recommending bimodal stimulation, who programs the hearing aid in the bimodal condition, and what method is used for programming the hearing aid? An 11-question online survey was created and sent via email to a comprehensive list of cochlear implant programming centers in the United States. The survey was sent to 360 recipients. Respondents in this study represented a diverse group of clinical settings (response rate: 26%). Results indicate little agreement about who programs the hearing aids, when they are programmed, and how they are programmed in the bimodal condition. Analysis of small versus large implant centers indicated small centers are less likely to add a device to the contralateral ear. Although a growing number of cochlear implant recipients choose to wear a hearing aid on the contralateral ear, there is inconsistency in the current clinical approach to bimodal programming. These survey results provide evidence of large variability in the current bimodal programming practices and indicate a need for more structured clinical recommendations and programming approaches.

  17. SIBER: systematic identification of bimodally expressed genes using RNAseq data.

    PubMed

    Tong, Pan; Chen, Yong; Su, Xiao; Coombes, Kevin R

    2013-03-01

    Identification of bimodally expressed genes is an important task, as genes with bimodal expression play important roles in cell differentiation, signalling and disease progression. Several useful algorithms have been developed to identify bimodal genes from microarray data. Currently, no method can deal with data from next-generation sequencing, which is emerging as a replacement technology for microarrays. We present SIBER (systematic identification of bimodally expressed genes using RNAseq data) for effectively identifying bimodally expressed genes from next-generation RNAseq data. We evaluate several candidate methods for modelling RNAseq count data and compare their performance in identifying bimodal genes through both simulation and real data analysis. We show that the lognormal mixture model performs best in terms of power and robustness under various scenarios. We also compare our method with alternative approaches, including profile analysis using clustering and kurtosis (PACK) and cancer outlier profile analysis (COPA). Our method is robust, powerful, invariant to shifting and scaling, has no blind spots and has a sample-size-free interpretation. The R package SIBER is available at the website http://bioinformatics.mdanderson.org/main/OOMPA:Overview.

  18. SIBER: systematic identification of bimodally expressed genes using RNAseq data

    PubMed Central

    Tong, Pan; Chen, Yong; Su, Xiao; Coombes, Kevin R.

    2013-01-01

    Motivation: Identification of bimodally expressed genes is an important task, as genes with bimodal expression play important roles in cell differentiation, signalling and disease progression. Several useful algorithms have been developed to identify bimodal genes from microarray data. Currently, no method can deal with data from next-generation sequencing, which is emerging as a replacement technology for microarrays. Results: We present SIBER (systematic identification of bimodally expressed genes using RNAseq data) for effectively identifying bimodally expressed genes from next-generation RNAseq data. We evaluate several candidate methods for modelling RNAseq count data and compare their performance in identifying bimodal genes through both simulation and real data analysis. We show that the lognormal mixture model performs best in terms of power and robustness under various scenarios. We also compare our method with alternative approaches, including profile analysis using clustering and kurtosis (PACK) and cancer outlier profile analysis (COPA). Our method is robust, powerful, invariant to shifting and scaling, has no blind spots and has a sample-size-free interpretation. Availability: The R package SIBER is available at the website http://bioinformatics.mdanderson.org/main/OOMPA:Overview. Contact: kcoombes@mdanderson.org Supplementary information: Supplementary data are available at Bioinformatics online. PMID:23303507

  19. Bimodal stimulus timing-dependent plasticity in primary auditory cortex is altered after noise exposure with and without tinnitus

    PubMed Central

    Koehler, Seth D.; Shore, Susan E.

    2015-01-01

    Central auditory circuits are influenced by the somatosensory system, a relationship that may underlie tinnitus generation. In the guinea pig dorsal cochlear nucleus (DCN), pairing spinal trigeminal nucleus (Sp5) stimulation with tones at specific intervals and orders facilitated or suppressed subsequent tone-evoked neural responses, reflecting spike timing-dependent plasticity (STDP). Furthermore, after noise-induced tinnitus, bimodal responses in DCN were shifted from Hebbian to anti-Hebbian timing rules with less discrete temporal windows, suggesting a role for bimodal plasticity in tinnitus. Here, we aimed to determine if multisensory STDP principles like those in DCN also exist in primary auditory cortex (A1), and whether they change following noise-induced tinnitus. Tone-evoked and spontaneous neural responses were recorded before and 15 min after bimodal stimulation in which the intervals and orders of auditory-somatosensory stimuli were randomized. Tone-evoked and spontaneous firing rates were influenced by the interval and order of the bimodal stimuli, and in sham-controls Hebbian-like timing rules predominated as was seen in DCN. In noise-exposed animals with and without tinnitus, timing rules shifted away from those found in sham-controls to more anti-Hebbian rules. Only those animals with evidence of tinnitus showed increased spontaneous firing rates, a purported neurophysiological correlate of tinnitus in A1. Together, these findings suggest that bimodal plasticity is also evident in A1 following noise damage and may have implications for tinnitus generation and therapeutic intervention across the central auditory circuit. PMID:26289461

  20. Bimodal stimulus timing-dependent plasticity in primary auditory cortex is altered after noise exposure with and without tinnitus.

    PubMed

    Basura, Gregory J; Koehler, Seth D; Shore, Susan E

    2015-12-01

    Central auditory circuits are influenced by the somatosensory system, a relationship that may underlie tinnitus generation. In the guinea pig dorsal cochlear nucleus (DCN), pairing spinal trigeminal nucleus (Sp5) stimulation with tones at specific intervals and orders facilitated or suppressed subsequent tone-evoked neural responses, reflecting spike timing-dependent plasticity (STDP). Furthermore, after noise-induced tinnitus, bimodal responses in DCN were shifted from Hebbian to anti-Hebbian timing rules with less discrete temporal windows, suggesting a role for bimodal plasticity in tinnitus. Here, we aimed to determine if multisensory STDP principles like those in DCN also exist in primary auditory cortex (A1), and whether they change following noise-induced tinnitus. Tone-evoked and spontaneous neural responses were recorded before and 15 min after bimodal stimulation in which the intervals and orders of auditory-somatosensory stimuli were randomized. Tone-evoked and spontaneous firing rates were influenced by the interval and order of the bimodal stimuli, and in sham-controls Hebbian-like timing rules predominated as was seen in DCN. In noise-exposed animals with and without tinnitus, timing rules shifted away from those found in sham-controls to more anti-Hebbian rules. Only those animals with evidence of tinnitus showed increased spontaneous firing rates, a purported neurophysiological correlate of tinnitus in A1. Together, these findings suggest that bimodal plasticity is also evident in A1 following noise damage and may have implications for tinnitus generation and therapeutic intervention across the central auditory circuit.

  1. Bimodal expression level polymorphisms in Arabidopsis thaliana

    PubMed Central

    Nagano, Atsushi J.; Tsuchimatsu, Takashi; Okuyama, Yudai; Hara-Nishimura, Ikuko

    2012-01-01

    Differences in gene expression are termed expression level polymorphisms (ELPs). Here, we propose a new ELP class, bimodal ELPs (bELPs), as a criterion to screen for genes that are responsible for natural phenotypic variation and/or that are targeted by balancing selection. bELP genes are characterized by two expression level modes. Genomic scans based on nucleotide sequences are not ideal for identifying genes targeted for selection. A critical concern is that several genes can be present in the selection-targeted regions identified by such scans. This situation indicates the importance of integrating genomic sequence data and other information, such as gene expression data. Comparative transcriptomics is useful for determining evolutionarily and ecologically important polymorphisms. In a genome-wide expression screen of 34 accessions, we identified 344 Arabidopsis thaliana genes exhibiting bELPs. Population genetic analysis revealed that bELP genes had high nucleotide diversities and long linkage disequilibriums. The highest nucleotide diversity (11-fold greater than the genomic mean) was found in the At1g23780 gene, which encodes a putative F-box protein. We observed a clear association between the expression mode and sequence type of the At1g23780 gene. Our results suggest that bELPs will be useful for the screening and functional analysis of genes responsible for phenotypic polymorphisms. Such a “multi-omics” approach has the potential to facilitate the scanning of genes relevant to balanced polymorphisms not only in A. thaliana, but also in other model and non-model organisms. PMID:22751308

  2. THE BIMODAL STRUCTURE OF THE SOLAR CYCLE

    SciTech Connect

    Du, Z. L.

    2015-05-01

    Some properties of the 11 yr solar cycle can be explained by the current solar dynamo models. However, some other features remain not well understood such as the asymmetry of the cycle, the double-peaked structure, and the “Waldmeier effect” that a stronger cycle tends to have less rise time and a shorter cycle length. We speculate that the solar cycle is governed by a bi-dynamo model forming two stochastic processes depicted by a bimodal Gaussian function with a time gap of about 2 yr, from which the above features can be reasonably explained. The first one describes the main properties of the cycle dominated by the current solar dynamo models, and the second one occurs either in the rising phase as a short weak explosive perturbation or in the declining phase as a long stochastic perturbation. The above function is the best one selected from several in terms of the Akaike information criterion. Through analyzing different distributions, one might speculate about the dominant physical process inside the convection zone. The secondary (main) process is found to be closely associated with complicated (simple) active ranges. In effect, the bi-dynamo model is a reduced form of a multi-dynamo model, which could occur from the base of the convection zone through its envelope and from low to high heliographic latitude, reflecting the active belts in the convection zone. These results are insensitive to the hemispheric asymmetry, smoothing filters, and distribution functions selected and are expected to be helpful in understanding the formation of solar and stellar cycles.

  3. Cometary coma ions. [water predominance

    NASA Technical Reports Server (NTRS)

    Aikin, A. C.

    1974-01-01

    For comets whose nuclei are composed of water ice conglomerates it is shown that the ion H3O(+) can predominate to distances of 5000 km in the subsolar direction. Beyond this distance H2O(+) is the most important ion. The crossover point is a sensitive function of the rate of evaporation from the nucleus. The presence of ammonia or metals such as sodium, in concentrations greater than 0.1% H2O, can lead to NH4(+) and Na(+) ions.

  4. Localization ability with bimodal hearing aids and bilateral cochlear implants

    NASA Astrophysics Data System (ADS)

    Seeber, Bernhard U.; Baumann, Uwe; Fastl, Hugo

    2004-09-01

    After successful cochlear implantation in one ear, some patients continue to use a hearing aid at the contralateral ear. They report an improved reception of speech, especially in noise, as well as a better perception of music when the hearing aid and cochlear implant are used in this bimodal combination. Some individuals in this bimodal patient group also report the impression of an improved localization ability. Similar experiences are reported by the group of bilateral cochlear implantees. In this study, a survey of 11 bimodally and 4 bilaterally equipped cochlear implant users was carried out to assess localization ability. Individuals in the bimodal implant group were all provided with the same type of hearing aid in the opposite ear, and subjects in the bilateral implant group used cochlear implants of the same manufacturer on each ear. Subjects adjusted the spot of a computer-controlled laser-pointer to the perceived direction of sound incidence in the frontal horizontal plane by rotating a trackball. Two subjects of the bimodal group who had substantial residual hearing showed localization ability in the bimodal configuration, whereas using each single device only the subject with better residual hearing was able to discriminate the side of sound origin. Five other subjects with more pronounced hearing loss displayed an ability for side discrimination through the use of bimodal aids, while four of them were already able to discriminate the side with a single device. Of the bilateral cochlear implant group one subject showed localization accuracy close to that of normal hearing subjects. This subject was also able to discriminate the side of sound origin using the first implanted device alone. The other three bilaterally equipped subjects showed limited localization ability using both devices. Among them one subject demonstrated a side-discrimination ability using only the first implanted device.

  5. Merging history of three bimodal clusters

    NASA Astrophysics Data System (ADS)

    Maurogordato, S.; Sauvageot, J. L.; Bourdin, H.; Cappi, A.; Benoist, C.; Ferrari, C.; Mars, G.; Houairi, K.

    2011-01-01

    We present a combined X-ray and optical analysis of three bimodal galaxy clusters selected as merging candidates at z ~ 0.1. These targets are part of MUSIC (MUlti-Wavelength Sample of Interacting Clusters), which is a general project designed to study the physics of merging clusters by means of multi-wavelength observations. Observations include spectro-imaging with XMM-Newton EPIC camera, multi-object spectroscopy (260 new redshifts), and wide-field imaging at the ESO 3.6 m and 2.2 m telescopes. We build a global picture of these clusters using X-ray luminosity and temperature maps together with galaxy density and velocity distributions. Idealized numerical simulations were used to constrain the merging scenario for each system. We show that A2933 is very likely an equal-mass advanced pre-merger ~200 Myr before the core collapse, while A2440 and A2384 are post-merger systems (~450 Myr and ~1.5 Gyr after core collapse, respectively). In the case of A2384, we detect a spectacular filament of galaxies and gas spreading over more than 1 h-1 Mpc, which we infer to have been stripped during the previous collision. The analysis of the MUSIC sample allows us to outline some general properties of merging clusters: a strong luminosity segregation of galaxies in recent post-mergers; the existence of preferential axes - corresponding to the merging directions - along which the BCGs and structures on various scales are aligned; the concomitance, in most major merger cases, of secondary merging or accretion events, with groups infalling onto the main cluster, and in some cases the evidence of previous merging episodes in one of the main components. These results are in good agreement with the hierarchical scenario of structure formation, in which clusters are expected to form by successive merging events, and matter is accreted along large-scale filaments. Based on data obtained with the European Southern Observatory, Chile (programs 072.A-0595, 075.A-0264, and 079.A-0425

  6. Perception of Sung Speech in Bimodal Cochlear Implant Users.

    PubMed

    Crew, Joseph D; Galvin, John J; Fu, Qian-Jie

    2016-11-11

    Combined use of a hearing aid (HA) and cochlear implant (CI) has been shown to improve CI users' speech and music performance. However, different hearing devices, test stimuli, and listening tasks may interact and obscure bimodal benefits. In this study, speech and music perception were measured in bimodal listeners for CI-only, HA-only, and CI + HA conditions, using the Sung Speech Corpus, a database of monosyllabic words produced at different fundamental frequencies. Sentence recognition was measured using sung speech in which pitch was held constant or varied across words, as well as for spoken speech. Melodic contour identification (MCI) was measured using sung speech in which the words were held constant or varied across notes. Results showed that sentence recognition was poorer with sung speech relative to spoken, with little difference between sung speech with a constant or variable pitch; mean performance was better with CI-only relative to HA-only, and best with CI + HA. MCI performance was better with constant words versus variable words; mean performance was better with HA-only than with CI-only and was best with CI + HA. Relative to CI-only, a strong bimodal benefit was observed for speech and music perception. Relative to the better ear, bimodal benefits remained strong for sentence recognition but were marginal for MCI. While variations in pitch and timbre may negatively affect CI users' speech and music perception, bimodal listening may partially compensate for these deficits.

  7. Functionalized bimodal mesoporous silicas as carriers for controlled aspirin delivery

    SciTech Connect

    Gao Lin; Sun Jihong; Li Yuzhen

    2011-08-15

    The bimodal mesoporous silica modified with 3-aminopropyltriethoxysilane was performed as the aspirin carrier. The samples' structure, drug loading and release profiles were characterized with X-ray diffraction, scanning electron microscopy, N{sub 2} adsorption and desorption, Fourier transform infrared spectroscopy, TG analysis, elemental analysis and UV-spectrophotometer. For further exploring the effects of the bimodal mesopores on the drug delivery behavior, the unimodal mesoporous material MCM-41 was also modified as the aspirin carrier. Meantime, Korsmeyer-Peppas equation f{sub t}=kt{sup n} was employed to analyze the dissolution data in details. It is indicated that the bimodal mesopores are beneficial for unrestricted drug molecules diffusing and therefore lead to a higher loading and faster releasing than that of MCM-41. The results show that the aspirin delivery properties are influenced considerably by the mesoporous matrix, whereas the large pore of bimodal mesoporous silica is the key point for the improved controlled-release properties. - Graphical abstract: Loading (A) and release profiles (B) of aspirin in N-BMMs and N-MCM-41 indicated that BMMs have more drug loading capacity and faster release rate than that MCM-41. Highlights: > Bimodal mesoporous silicas (BMMs) and MCM-41 modified with amino group via post-treatment procedure. > Loading and release profiles of aspirin in modified BMMs and MCM-41. > Modified BMMs have more drug loading capacity and faster release rate than that modified MCM-41.

  8. Bimodal bilingualism and the frequency-lag hypothesis.

    PubMed

    Emmorey, Karen; Petrich, Jennifer A F; Gollan, Tamar H

    2013-01-01

    The frequency-lag hypothesis proposes that bilinguals have slowed lexical retrieval relative to monolinguals and in their nondominant language relative to their dominant language, particularly for low-frequency words. These effects arise because bilinguals divide their language use between 2 languages and use their nondominant language less frequently. We conducted a picture-naming study with hearing American Sign Language (ASL)-English bilinguals (bimodal bilinguals), deaf signers, and English-speaking monolinguals. As predicted by the frequency-lag hypothesis, bimodal bilinguals were slower, less accurate, and exhibited a larger frequency effect when naming pictures in ASL as compared with English (their dominant language) and as compared with deaf signers. For English there was no difference in naming latencies, error rates, or frequency effects for bimodal bilinguals as compared with monolinguals. Neither age of ASL acquisition nor interpreting experience affected the results; picture-naming accuracy and frequency effects were equivalent for deaf signers and English monolinguals. Larger frequency effects in ASL relative to English for bimodal bilinguals suggests that they are affected by a frequency lag in ASL. The absence of a lag for English could reflect the use of mouthing and/or code-blending, which may shield bimodal bilinguals from the lexical slowing observed for spoken language bilinguals in the dominant language.

  9. Perception of Sung Speech in Bimodal Cochlear Implant Users

    PubMed Central

    Galvin, John J.; Fu, Qian-Jie

    2016-01-01

    Combined use of a hearing aid (HA) and cochlear implant (CI) has been shown to improve CI users’ speech and music performance. However, different hearing devices, test stimuli, and listening tasks may interact and obscure bimodal benefits. In this study, speech and music perception were measured in bimodal listeners for CI-only, HA-only, and CI + HA conditions, using the Sung Speech Corpus, a database of monosyllabic words produced at different fundamental frequencies. Sentence recognition was measured using sung speech in which pitch was held constant or varied across words, as well as for spoken speech. Melodic contour identification (MCI) was measured using sung speech in which the words were held constant or varied across notes. Results showed that sentence recognition was poorer with sung speech relative to spoken, with little difference between sung speech with a constant or variable pitch; mean performance was better with CI-only relative to HA-only, and best with CI + HA. MCI performance was better with constant words versus variable words; mean performance was better with HA-only than with CI-only and was best with CI + HA. Relative to CI-only, a strong bimodal benefit was observed for speech and music perception. Relative to the better ear, bimodal benefits remained strong for sentence recognition but were marginal for MCI. While variations in pitch and timbre may negatively affect CI users’ speech and music perception, bimodal listening may partially compensate for these deficits. PMID:27837051

  10. Bimodal Bilingualism and the Frequency-Lag Hypothesis

    PubMed Central

    Emmorey, Karen

    2013-01-01

    The frequency-lag hypothesis proposes that bilinguals have slowed lexical retrieval relative to monolinguals and in their nondominant language relative to their dominant language, particularly for low-frequency words. These effects arise because bilinguals divide their language use between 2 languages and use their nondominant language less frequently. We conducted a picture-naming study with hearing American Sign Language (ASL)–English bilinguals (bimodal bilinguals), deaf signers, and English-speaking monolinguals. As predicted by the frequency-lag hypothesis, bimodal bilinguals were slower, less accurate, and exhibited a larger frequency effect when naming pictures in ASL as compared with English (their dominant language) and as compared with deaf signers. For English there was no difference in naming latencies, error rates, or frequency effects for bimodal bilinguals as compared with monolinguals. Neither age of ASL acquisition nor interpreting experience affected the results; picture-naming accuracy and frequency effects were equivalent for deaf signers and English monolinguals. Larger frequency effects in ASL relative to English for bimodal bilinguals suggests that they are affected by a frequency lag in ASL. The absence of a lag for English could reflect the use of mouthing and/or code-blending, which may shield bimodal bilinguals from the lexical slowing observed for spoken language bilinguals in the dominant language. PMID:23073709

  11. High-temperature hydrothermal alteration of tje Boehls Butte anorthosite: Origin of a bimodal plagioclase assemblage

    SciTech Connect

    Mora, Claudia I; Riciputi, Lee R; Cole, David; Walker, Karen

    2008-01-01

    The Boehls Butte anorthosite consists predominantly of an unusual bimodal assemblage of andesine and bytownite anorthite. Oxygen isotope compositions of the anorthosite were profoundly altered by high temperature, retrograde interaction with meteorichydrothermal fluids that varied in composition from isotopically evolved to nearly pristine meteoric water. Oxygen isotope ratios of bulk plagioclase separates are in the range ?7.0 to -6.2% V-SMOW, however, secondary ion mass spectrometry indicates spot-sized isotope values as low as -16%. Typical inter- and intra-plagioclase grain variability is 3 6%, and extreme heterogeneity of up to 20%is noted in a few samples. High-temperature hydrothermal alteration of intermediate plagioclase is proposed to explain the origin of bytownite anorthite in the anorthosite and creation of its unusual bimodal plagioclase assemblage. The anorthite-forming reaction created retrograde reaction-enhanced permeability which, together with rapid decompression, extension, and unroofing of the anorthosite complex, helped to accommodated influx of significant volumes of meteoric-hydrothermal fluids into the anorthosite.

  12. Rotational multispectral fluorescence lifetime imaging and intravascular ultrasound: bimodal system for intravascular applications

    PubMed Central

    Ma, Dinglong; Bec, Julien; Yankelevich, Diego R.; Gorpas, Dimitris; Fatakdawala, Hussain; Marcu, Laura

    2014-01-01

    Abstract. We report the development and validation of a hybrid intravascular diagnostic system combining multispectral fluorescence lifetime imaging (FLIm) and intravascular ultrasound (IVUS) for cardiovascular imaging applications. A prototype FLIm system based on fluorescence pulse sampling technique providing information on artery biochemical composition was integrated with a commercial IVUS system providing information on artery morphology. A customized 3-Fr bimodal catheter combining a rotational side-view fiberoptic and a 40-MHz IVUS transducer was constructed for sequential helical scanning (rotation and pullback) of tubular structures. Validation of this bimodal approach was conducted in pig heart coronary arteries. Spatial resolution, fluorescence detection efficiency, pulse broadening effect, and lifetime measurement variability of the FLIm system were systematically evaluated. Current results show that this system is capable of temporarily resolving the fluorescence emission simultaneously in multiple spectral channels in a single pullback sequence. Accurate measurements of fluorescence decay characteristics from arterial segments can be obtained rapidly (e.g., 20 mm in 5 s), and accurate co-registration of fluorescence and ultrasound features can be achieved. The current finding demonstrates the compatibility of FLIm instrumentation with in vivo clinical investigations and its potential to complement conventional IVUS during catheterization procedures. PMID:24898604

  13. Rotational multispectral fluorescence lifetime imaging and intravascular ultrasound: bimodal system for intravascular applications

    NASA Astrophysics Data System (ADS)

    Ma, Dinglong; Bec, Julien; Yankelevich, Diego R.; Gorpas, Dimitris; Fatakdawala, Hussain; Marcu, Laura

    2014-06-01

    We report the development and validation of a hybrid intravascular diagnostic system combining multispectral fluorescence lifetime imaging (FLIm) and intravascular ultrasound (IVUS) for cardiovascular imaging applications. A prototype FLIm system based on fluorescence pulse sampling technique providing information on artery biochemical composition was integrated with a commercial IVUS system providing information on artery morphology. A customized 3-Fr bimodal catheter combining a rotational side-view fiberoptic and a 40-MHz IVUS transducer was constructed for sequential helical scanning (rotation and pullback) of tubular structures. Validation of this bimodal approach was conducted in pig heart coronary arteries. Spatial resolution, fluorescence detection efficiency, pulse broadening effect, and lifetime measurement variability of the FLIm system were systematically evaluated. Current results show that this system is capable of temporarily resolving the fluorescence emission simultaneously in multiple spectral channels in a single pullback sequence. Accurate measurements of fluorescence decay characteristics from arterial segments can be obtained rapidly (e.g., 20 mm in 5 s), and accurate co-registration of fluorescence and ultrasound features can be achieved. The current finding demonstrates the compatibility of FLIm instrumentation with in vivo clinical investigations and its potential to complement conventional IVUS during catheterization procedures.

  14. Neural activity profiles of the neocortex and superior colliculus after bimodal sensory stimulation.

    PubMed

    Zangenehpour, S; Chaudhuri, A

    2001-10-01

    Current efforts at functional mapping of multisensory neurons are hampered by the need for both cellular-level resolution and the separate visualization of activity by different sensory cues. We have used a recently developed technique that exploits the differential time course of zif268 mRNA versus protein induction in neurons after sensory stimulation. Adult male rats were visually and acoustically deprived and then exposed to one of the following stimulation sequences: (i) no sensory stimulation; (ii) 2 h visual stimulation followed by 30 min auditory stimulation; (iii) 2 h auditory stimulation followed 30 min of visual stimulation; and (iv) 2 h compound visual and auditory stimulation. The neocortex and superior colliculus (SC) were then processed for fluorescent immunocytochemistry and in situ hybridization for staining of Zif268 protein and mRNA products. We have found that activity patterns in primary visual and auditory cortices were in accord with the sequence of the compound stimulus. We also show that SC superficial layers contained a pool of exclusively unimodal neurons, similar to that of visual cortex. Activity patterns of deep SC layers contained multimodal neurons with varying degrees of visual and auditory convergence. The deep SC layers also showed that auditory processing was largely carried out by a small, bimodal group of neurons whereas visual processing was coordinated by both a large unimodal and a small bimodal pool of neurons.

  15. Generalized oddity performance in preschool children: a bimodal training procedure.

    PubMed

    Soraci, S A; Deckner, C W; Baumeister, A A; Bryant, J T; Mackay, H A; Stoddard, L T; McIlvane, W J

    1991-04-01

    Oddity performance requires relational discriminative responding, which typically is difficult to establish in children with MAs below five. In Experiment 1, a combination intrasubject reversal and multiple baseline across subjects design was used to establish the internal validity of a bimodal intervention in establishing generalized oddity performance. Six of seven children demonstrated oddity responding when presented with stimuli that instantiated the oddity relation in the visual and auditory modalities simultaneously. Oddity performance was evaluated with both reversal assessments and assessments with new sets of stimuli. The newly acquired oddity performance was durable; the six children continued to respond discriminatively when returned to a visual-only task on which they previously had been unsuccessful. Utilizing a reversal assessment more stringent than that of Experiment 1, Experiment 2 replicated this effect. The present studies are the first to demonstrate the utility of bimodal training in establishing oddity performance. The bimodal procedure is discussed with respect to the theoretical positions of Gibson, Dinsmoor, and Dixon.

  16. Aggressive Bimodal Communication in Domestic Dogs, Canis familiaris.

    PubMed

    Déaux, Éloïse C; Clarke, Jennifer A; Charrier, Isabelle

    2015-01-01

    Evidence of animal multimodal signalling is widespread and compelling. Dogs' aggressive vocalisations (growls and barks) have been extensively studied, but without any consideration of the simultaneously produced visual displays. In this study we aimed to categorize dogs' bimodal aggressive signals according to the redundant/non-redundant classification framework. We presented dogs with unimodal (audio or visual) or bimodal (audio-visual) stimuli and measured their gazing and motor behaviours. Responses did not qualitatively differ between the bimodal and two unimodal contexts, indicating that acoustic and visual signals provide redundant information. We could not further classify the signal as 'equivalent' or 'enhancing' as we found evidence for both subcategories. We discuss our findings in relation to the complex signal framework, and propose several hypotheses for this signal's function.

  17. Bimodal Distribution of Magnetic Fields and Areas of Sunspots

    NASA Astrophysics Data System (ADS)

    Tlatov, Andrey G.; Pevtsov, Alexei A.

    2014-04-01

    We applied automatic identification of sunspot umbrae and penumbrae to daily observations from the Helioseismic Magnetic Imager (HMI) on board the Solar Dynamics Observatory (SDO) to study their magnetic flux density ( B) and area ( A). The results confirm an already known logarithmic relationship between the area of sunspots and their maximum flux density. In addition, we find that the relation between average magnetic flux density () and sunspot area shows a bimodal distribution: for small sunspots and pores ( A≤20 millionth of solar hemisphere, MSH), (gauss), and for large sunspots ( A≥100 MSH), is about 600 G. For intermediate sunspots, average flux density linearly decreases from about 800 G to 600 G. A similar bimodal distribution was found in several other integral parameters of sunspots. We show that this bimodality can be related to different stages of sunspot penumbra formation and can be explained by the difference in average inclination of magnetic fields at the periphery of small and large sunspots.

  18. Aggressive Bimodal Communication in Domestic Dogs, Canis familiaris

    PubMed Central

    Déaux, Éloïse C.; Clarke, Jennifer A.; Charrier, Isabelle

    2015-01-01

    Evidence of animal multimodal signalling is widespread and compelling. Dogs’ aggressive vocalisations (growls and barks) have been extensively studied, but without any consideration of the simultaneously produced visual displays. In this study we aimed to categorize dogs’ bimodal aggressive signals according to the redundant/non-redundant classification framework. We presented dogs with unimodal (audio or visual) or bimodal (audio-visual) stimuli and measured their gazing and motor behaviours. Responses did not qualitatively differ between the bimodal and two unimodal contexts, indicating that acoustic and visual signals provide redundant information. We could not further classify the signal as ‘equivalent’ or ‘enhancing’ as we found evidence for both subcategories. We discuss our findings in relation to the complex signal framework, and propose several hypotheses for this signal’s function. PMID:26571266

  19. Predominant discourses in Swedish nursing.

    PubMed

    Dahlborg-Lyckhage, Elisabeth; Pilhammar-Anderson, Ewa

    2009-05-01

    The aim of this study was to elucidate the predominant discourse in the field of Swedish nursing in 2000, 25 years after nursing was introduced as an academic discipline in Sweden. The method used was content analysis and deconstructive analysis of discourses. Laws, statutes, regulations, and examination requirements, including official reports, recruitment campaigns, and media coverage, were analyzed. The findings uncovered competing discourses striving to gain hegemony. In the public sector, official requirements competed against the media fixation on gender stereotypes and the realities of local recruitment campaigns. Media has a major role in disseminating prevailing conceptions and conventions pertaining to the nursing profession. As a result, decision makers, students, patients, and family members could get lower expectations of the professional competence of nursing practitioners than would otherwise have been the case in the absence of media exposure.

  20. Bimodal SLD Ice Accretion on a NACA 0012 Airfoil Model

    NASA Technical Reports Server (NTRS)

    Potapczuk, Mark; Tsao, Jen-Ching; King-Steen, Laura

    2016-01-01

    This presentation describes the results of ice accretion measurements on a NACA 0012 airfoil model, from the NASA Icing Research Tunnel, using an icing cloud composed of a bimodal distribution of Supercooled Large Droplets. The data consists of photographs, laser scans of the ice surface, and measurements of the mass of ice for each icing condition. The results of ice shapes accumulated as a result of exposure to an icing cloud with a bimodal droplet distribution were compared to the ice shapes resulting from an equivalent cloud composed of a droplet distribution with a standard bell curve shape.

  1. Trajectory Optimization of a Bimodal Nuclear Powered Spacecraft to Mars

    DTIC Science & Technology

    1990-05-29

    high power bimodal system has been designed , it will be assumed in this initial optimization that a separate power source shall be carried...utilizing the rocket reactor in a low power output mode when the high thrusting rocket was not in use. The power created was designated for use by the...to .30. For a non-bimodal system, i.e. separate reactors for the high thrust and power generation systems, one may set 1 -0.0 or 1WL T IV-28 Power

  2. Darcian preferential water flow and solute transport through bimodal porous systems: experiments and modelling.

    PubMed

    Coppola, Antonio; Comegna, Vincenzo; Basile, Angelo; Lamaddalena, Nicola; Severino, Gerardo

    2009-02-16

    Soils often exhibit a variety of small-scale heterogeneities such as inter-aggregate pores and voids which partition flow into separate regions. In this paper a methodological approach is discussed for characterizing the hydrological behaviour of a heterogeneous clayey-sandy soil in the presence of structural inter-aggregate pores. For the clay soil examined, it was demonstrated that, coupling the transfer function approach for analyzing BTCs and water retention data obtained with different methods from laboratory studies captures the bimodal geometry of the porous system along with the related existence of fast and slow flow paths. To be effectively and reliably applied this approach requires that the predominant effects of the soil hydrological behaviour near saturation be supported by accurate experimental data of both breakthrough curves (BTCs) and hydraulic functions for high water content values. This would allow the separation of flow phases and hence accurate identification of the processes and related parameters.

  3. Particle filtering with path sampling and an application to a bimodal ocean current model

    SciTech Connect

    Weare, Jonathan

    2009-07-01

    This paper introduces a recursive particle filtering algorithm designed to filter high dimensional systems with complicated non-linear and non-Gaussian effects. The method incorporates a parallel marginalization (PMMC) step in conjunction with the hybrid Monte Carlo (HMC) scheme to improve samples generated by standard particle filters. Parallel marginalization is an efficient Markov chain Monte Carlo (MCMC) strategy that uses lower dimensional approximate marginal distributions of the target distribution to accelerate equilibration. As a validation the algorithm is tested on a 2516 dimensional, bimodal, stochastic model motivated by the Kuroshio current that runs along the Japanese coast. The results of this test indicate that the method is an attractive alternative for problems that require the generality of a particle filter but have been inaccessible due to the limitations of standard particle filtering strategies.

  4. Measuring oxygen uptake in fishes with bimodal respiration.

    PubMed

    Lefevre, S; Bayley, M; McKenzie, D J

    2016-01-01

    Respirometry is a robust method for measurement of oxygen uptake as a proxy for metabolic rate in fishes, and how species with bimodal respiration might meet their demands from water v. air has interested researchers for over a century. The challenges of measuring oxygen uptake from both water and air, preferably simultaneously, have been addressed in a variety of ways, which are briefly reviewed. These methods are not well-suited for the long-term measurements necessary to be certain of obtaining undisturbed patterns of respiratory partitioning, for example, to estimate traits such as standard metabolic rate. Such measurements require automated intermittent-closed respirometry that, for bimodal fishes, has only recently been developed. This paper describes two approaches in enough detail to be replicated by the interested researcher. These methods are for static respirometry. Measuring oxygen uptake by bimodal fishes during exercise poses specific challenges, which are described to aid the reader in designing experiments. The respiratory physiology and behaviour of air-breathing fishes is very complex and can easily be influenced by experimental conditions, and some general considerations are listed to facilitate the design of experiments. Air breathing is believed to have evolved in response to aquatic hypoxia and, probably, associated hypercapnia. The review ends by considering what realistic hypercapnia is, how hypercapnic tropical waters can become and how this might influence bimodal animals' gas exchange.

  5. Bimodal Bilingual Language Development of Hearing Children of Deaf Parents

    ERIC Educational Resources Information Center

    Hofmann, Kristin; Chilla, Solveig

    2015-01-01

    Adopting a bimodal bilingual language acquisition model, this qualitative case study is the first in Germany to investigate the spoken and sign language development of hearing children of deaf adults (codas). The spoken language competence of six codas within the age range of 3;10 to 6;4 is assessed by a series of standardised tests (SETK 3-5,…

  6. Bimodal Hearing and Speech Perception with a Competing Talker

    ERIC Educational Resources Information Center

    Pyschny, Verena; Landwehr, Markus; Hahn, Moritz; Walger, Martin; von Wedel, Hasso; Meister, Hartmut

    2011-01-01

    Purpose: The objective of the study was to investigate the influence of bimodal stimulation upon hearing ability for speech recognition in the presence of a single competing talker. Method: Speech recognition was measured in 3 listening conditions: hearing aid (HA) alone, cochlear implant (CI) alone, and both devices together (CI + HA). To examine…

  7. Bimodal Hearing and Speech Perception with a Competing Talker

    ERIC Educational Resources Information Center

    Pyschny, Verena; Landwehr, Markus; Hahn, Moritz; Walger, Martin; von Wedel, Hasso; Meister, Hartmut

    2011-01-01

    Purpose: The objective of the study was to investigate the influence of bimodal stimulation upon hearing ability for speech recognition in the presence of a single competing talker. Method: Speech recognition was measured in 3 listening conditions: hearing aid (HA) alone, cochlear implant (CI) alone, and both devices together (CI + HA). To examine…

  8. The Bimodal Color Distribution of Small Kuiper Belt Objects

    NASA Astrophysics Data System (ADS)

    Wong, Ian; Brown, Michael E.

    2017-04-01

    We conducted a two-night photometric survey of small Kuiper Belt objects (KBOs) near opposition using the wide-field Hyper Suprime-Cam instrument on the 8.2 m Subaru Telescope. The survey covered about 90 deg2 of sky, with each field imaged in the g and i bands. We detected 356 KBOs, ranging in absolute magnitude from 6.5 to 10.4. Filtering for high-inclination objects within the hot KBO population, we show that the g ‑ i color distribution is strongly bimodal, indicative of two color classes—the red and very red subpopulations. After categorizing objects into the two subpopulations by color, we present the first dedicated analysis of the magnitude distributions of the individual color subpopulations and demonstrate that the two distributions are roughly identical in shape throughout the entire size range covered by our survey. Comparing the color distribution of small hot KBOs with that of Centaurs, we find that they have similar bimodal shapes, thereby providing strong confirmation of previous explanations for the attested bimodality of Centaurs. We also show that the magnitude distributions of the two KBO color subpopulations and the two color subpopulations observed in the Jupiter Trojans are statistically indistinguishable. Finally, we discuss a hypothesis describing the origin of the KBO color bimodality based on our survey results. Based on data collected at Subaru Telescope, which is operated by the National Astronomical Observatory of Japan.

  9. Bimodal Bilingual Language Development of Hearing Children of Deaf Parents

    ERIC Educational Resources Information Center

    Hofmann, Kristin; Chilla, Solveig

    2015-01-01

    Adopting a bimodal bilingual language acquisition model, this qualitative case study is the first in Germany to investigate the spoken and sign language development of hearing children of deaf adults (codas). The spoken language competence of six codas within the age range of 3;10 to 6;4 is assessed by a series of standardised tests (SETK 3-5,…

  10. Bifurcation Structures in a Bimodal Piecewise Linear Map: Chaotic Dynamics

    NASA Astrophysics Data System (ADS)

    Panchuk, Anastasiia; Sushko, Iryna; Avrutin, Viktor

    In this work, we investigate the bifurcation structure of the parameter space of a generic 1D continuous piecewise linear bimodal map focusing on the regions associated with chaotic attractors (cyclic chaotic intervals). The boundaries of these regions corresponding to chaotic attractors with different number of intervals are identified. The results are obtained analytically using the skew tent map and the map replacement technique.

  11. SEP BIMOD variable conductance heat pipes acceptance and characterization tests

    NASA Technical Reports Server (NTRS)

    Hemminger, J. A.

    1981-01-01

    A series of six heat pipes, similar in design to those flown on the Comunications Technology Satellite Hermes, for use in a prototype Solar Electric Propulsion BIMOD thrust module are evaluated. The results of acceptance and characterization tests performed on the heat pipe subassemble are reported. The performance of all the heat pipes met, or exceeded, design specifications.

  12. [Cutaneous loxoscelism with edematous predominance].

    PubMed

    Schenone, H

    1998-01-01

    Loxoscelism is the clinical condition produced by the venom of spiders belonging to the genus Loxosceles. Human cases of loxoscelism have been observed in diverse countries of different continents in temperate and tropical regions. In Chile loxoscelism is caused by Loxosceles laeta, spider with domestic habits. Loxoscelism can be observed into two well definited clinical variants: cutaneous loxoscelism (CL) and systemic or viscerocutaneous loxoscelism (VCL) which occur in around 83.3 and 16.7% cases respectively. Within the universe of CL patients a clinical modality in which necrotic lesion is not present or is insignificant, but presenting a remarkable edema, particularly when the bite is on the face, which has received the name of CL with an edematous predominance (CLEP). In this paper the individual description and the assambled analysis of 10 cases, four males and six females, age ranging from 6 to 68 years, of CLEP are presented. Nine cases occurred in warm periods spring through fall and one in winter. In six cases the accident causing spider was seen and two of these were identified as L. laeta adult females. In all cases the patients went or were transported to emergency medical services 4-24 h after the bite. The predominant initial symptom was a burning stinging sensation at the site of the bite, followed by intensive pain which expanded the neighbour areas concomitantly with the emerging and progressive edema. In four of the nine patients in who the bite was on the face, the edema involved all of it, closed both eyelids and expanded to the neck and upper part of the thorax. In three cases the enormous edema was the only significant clinical manifestation, whereas in the remaining seven conjunctly with the edema, a small violaceous plaque or a blister of serous content gave place to a little livedoid plaque (diameter 0.3-0.8 cm) which evolved to desquamation without leaving any scarring. The edema was characterized by its brilliant rose color, painful

  13. A Hypothesis for the Color Bimodality of Jupiter Trojans

    NASA Astrophysics Data System (ADS)

    Wong, Ian; Brown, Michael E.

    2016-10-01

    One of the most enigmatic and hitherto unexplained properties of Jupiter Trojans is their bimodal color distribution. This bimodality is indicative of two sub-populations within the Trojans, which have distinct size distributions. In this paper, we present a simple, plausible hypothesis for the origin and evolution of the two Trojan color sub-populations. In the framework of dynamical instability models of early solar system evolution, which suggest a common primordial progenitor population for both Trojans and Kuiper Belt objects, we use observational constraints to assert that the color bimodalities evident in both minor body populations developed within the primordial population prior to the onset of instability. We show that, beginning with an initial composition of rock and ices, location-dependent volatile loss through sublimation in this primordial population could have led to sharp changes in the surface composition with heliocentric distance. We propose that the depletion or retention of H2S ice on the surface of these objects was the key factor in creating an initial color bimodality. Objects that retained H2S on their surfaces developed characteristically redder colors upon irradiation than those that did not. After the bodies from the primordial population were scattered and emplaced into their current positions, they preserved this primordial color bimodality to the present day. We explore predictions of the volatile loss model—in particular, the effect of collisions within the Trojan population on the size distributions of the two sub-populations—and propose further experimental and observational tests of our hypothesis.

  14. Pitch Adaptation Patterns in Bimodal Cochlear Implant Users: Over Time and After Experience

    PubMed Central

    Reiss, Lina A.J.; Ito, Rindy A.; Eggleston, Jessica L.; Liao, Selena; Becker, Jillian J.; Lakin, Carrie E.; Warren, Frank M.; McMenomey, Sean O.

    2014-01-01

    Background Pitch plasticity has been observed in Hybrid cochlear implant (CI) users. Does pitch plasticity also occur in bimodal CI users with traditional long-electrode CIs, and is pitch adaptation pattern associated with electrode discrimination or speech recognition performance? Objective Characterize pitch adaptation patterns in long-electrode CI users, correlate these patterns with electrode discrimination and speech perception outcomes, and analyze which subject factors are associated with the different patterns. Methods Electric-to-acoustic pitch matches were obtained in 19 subjects over time from CI activation to at least 12 months after activation, and in a separate group of 18 subjects in a single visit after at least 24 months of CI experience. Audiometric thresholds, electrode discrimination performance, and speech perception scores were also measured. Results Subjects measured over time had pitch adaptation patterns that fit one of the following categories: 1) “Pitch-adapting”, i.e. the mismatch between perceived electrode pitch and the corresponding frequency-to-electrode allocations decreased; 2) “Pitch-dropping”, i.e. the pitches of multiple electrodes dropped and converged to a similar low pitch; 3) “Pitch-unchanging”, i.e. electrode pitches did not change. Subjects measured after CI experience had a parallel set of adaptation patterns: 1) “Matched-pitch”, i.e. the electrode pitch was matched to the frequency allocation; 2) “Low-pitch”, i.e. the pitches of multiple electrodes were all around the lowest frequency allocation; 3) “Nonmatched-pitch”, i.e. the pitch patterns were compressed relative to the frequency allocations and did not fit either the matched-pitch or low-pitch categories. Unlike Hybrid CI users which were mostly in the pitch-adapting/matched-pitch category, the majority of bimodal CI users were in the latter two categories, pitch-dropping/low-pitch or pitch-unchanging/nonmatched-pitch. Subjects with pitch

  15. Pitch adaptation patterns in bimodal cochlear implant users: over time and after experience.

    PubMed

    Reiss, Lina A J; Ito, Rindy A; Eggleston, Jessica L; Liao, Selena; Becker, Jillian J; Lakin, Carrie E; Warren, Frank M; McMenomey, Sean O

    2015-01-01

    Pitch plasticity has been observed in Hybrid cochlear implant (CI) users. Does pitch plasticity also occur in bimodal CI users with traditional long-electrode CIs, and is pitch adaptation pattern associated with electrode discrimination or speech recognition performance? The goals of this study were to characterize pitch adaptation patterns in long-electrode CI users, to correlate these patterns with electrode discrimination and speech perception outcomes, and to analyze which subject factors are associated with the different patterns. Electric-to-acoustic pitch matches were obtained in 19 subjects over time from CI activation to at least 12 months after activation, and in a separate group of 18 subjects in a single visit after at least 24 months of CI experience. Audiometric thresholds, electrode discrimination performance, and speech perception scores were also measured. Subjects measured over time had pitch adaptation patterns that fit one of the following categories: (1) "Pitch-adapting," that is, the mismatch between perceived electrode pitch and the corresponding frequency-to-electrode allocations decreased; (2) "Pitch-dropping," that is, the pitches of multiple electrodes dropped and converged to a similar low-pitch; and (3) "Pitch-unchanging," that is, the electrode pitches did not change. Subjects measured after CI experience had a parallel set of adaptation patterns: (1) "Matched-pitch," that is, the electrode pitch was matched to the frequency allocation; (2) "Low-pitch," that is, the pitches of multiple electrodes were all around the lowest frequency allocation; and (3) "Nonmatched-pitch," that is, the pitch patterns were compressed relative to the frequency allocations and did not fit either the matched-pitch or low-pitch categories. Unlike Hybrid CI users which were mostly in the pitch-adapting or matched-pitch category, the majority of bimodal CI users were in the latter two categories, pitch-dropping/low-pitch or pitch

  16. Experimental, analytical and computational investigation of bimodal elastomer networks

    NASA Astrophysics Data System (ADS)

    von Lockette, Paris Robert

    Advances in the synthesis of macromolecular materials have led to the creation of special classes of elastomers called bimodal because of their bimodal distributions of linear starting oligomers. Numerous studies on these materials have documented anomalous increases in ultimate strength and toughness at certain mixture combinations of the constituents but have not yet identified a cause for this behavior. In addition, the ability to predict optimal mixtures still eludes polymer chemists. Constitutive models for the behavior of bimodal materials are also unable to predict material behavior, but instead tend to capture results using complicated curve fitting and iterative schemes. This thesis uncovers topological and micromechanical sources of these enhanced properties using periodic, topological simulations of chain-level network formation and develops a constitutive model of the aggregate bimodal network. Using a topological framework, in conjunction with the eight-chain averaging scheme of Arruda and Boyce, this work develops optical and mechanical constitutive models for bimodal elastomers whose results compare favorably with data in the literature. The resulting bimodal network theory is able to predict material response for a range of bimodal compositions using only two sets of data, a direct improvement over previous models. The micromechanics of elastomeric deformation and chain orientation as described by the eight-chain model are further validated by comparing optical and mechanical data generated during large deformation shear tests on unimodal materials with finite element simulations. In addition, a newly developed optical anisotropy model for the Raman tensor of polymeric materials, generated using an eight-chain unit cell model, is shown to compare favorably with tensile data in the literature. Results generated using NETSIM, a computer program developed in this thesis, have revealed naturally occurring, self-reinforcing topological features

  17. Rapid intensification and the bimodal distribution of tropical cyclone intensity

    PubMed Central

    Lee, Chia-Ying; Tippett, Michael K.; Sobel, Adam H.; Camargo, Suzana J.

    2016-01-01

    The severity of a tropical cyclone (TC) is often summarized by its lifetime maximum intensity (LMI), and the climatological LMI distribution is a fundamental feature of the climate system. The distinctive bimodality of the LMI distribution means that major storms (LMI >96 kt) are not very rare compared with less intense storms. Rapid intensification (RI) is the dramatic strengthening of a TC in a short time, and is notoriously difficult to forecast or simulate. Here we show that the bimodality of the LMI distribution reflects two types of storms: those that undergo RI during their lifetime (RI storms) and those that do not (non-RI storms). The vast majority (79%) of major storms are RI storms. Few non-RI storms (6%) become major storms. While the importance of RI has been recognized in weather forecasting, our results demonstrate that RI also plays a crucial role in the TC climatology. PMID:26838056

  18. The Development of Bimodal Bilingualism: Implications for Linguistic Theory.

    PubMed

    Lillo-Martin, Diane; de Quadros, Ronice Müller; Pichler, Deborah Chen

    2016-01-01

    A wide range of linguistic phenomena contribute to our understanding of the architecture of the human linguistic system. In this paper we present a proposal dubbed Language Synthesis to capture bilingual phenomena including code-switching and 'transfer' as automatic consequences of the addition of a second language, using basic concepts of Minimalism and Distributed Morphology. Bimodal bilinguals, who use a sign language and a spoken language, provide a new type of evidence regarding possible bilingual phenomena, namely code-blending, the simultaneous production of (aspects of) a message in both speech and sign. We argue that code-blending also follows naturally once a second articulatory interface is added to the model. Several different types of code-blending are discussed in connection to the predictions of the Synthesis model. Our primary data come from children developing as bimodal bilinguals, but our proposal is intended to capture a wide range of bilingual effects across any language pair.

  19. A novel broadband bi-mode active frequency selective surface

    NASA Astrophysics Data System (ADS)

    Xu, Yang; Gao, Jinsong; Xu, Nianxi; Shan, Dongzhi; Song, Naitao

    2017-05-01

    A novel broadband bi-mode active frequency selective surface (AFSS) is presented in this paper. The proposed structure is composed of a periodic array of convoluted square patches and Jerusalem Crosses. According to simulation results, the frequency response of AFSS definitely exhibits a mode switch feature between band-pass and band-stop modes when the diodes stay in ON and OFF states. In order to apply a uniform bias to each PIN diode, an ingenious biasing network based on the extension of Wheatstone bridge is adopted in prototype AFSS. The test results are in good agreement with the simulation results. A further physical mechanism of the bi-mode AFSS is shown by contrasting the distribution of electric field on the AFSS patterns for the two working states.

  20. The Development of Bimodal Bilingualism: Implications for Linguistic Theory

    PubMed Central

    Lillo-Martin, Diane; de Quadros, Ronice Müller; Pichler, Deborah Chen

    2017-01-01

    A wide range of linguistic phenomena contribute to our understanding of the architecture of the human linguistic system. In this paper we present a proposal dubbed Language Synthesis to capture bilingual phenomena including code-switching and ‘transfer’ as automatic consequences of the addition of a second language, using basic concepts of Minimalism and Distributed Morphology. Bimodal bilinguals, who use a sign language and a spoken language, provide a new type of evidence regarding possible bilingual phenomena, namely code-blending, the simultaneous production of (aspects of) a message in both speech and sign. We argue that code-blending also follows naturally once a second articulatory interface is added to the model. Several different types of code-blending are discussed in connection to the predictions of the Synthesis model. Our primary data come from children developing as bimodal bilinguals, but our proposal is intended to capture a wide range of bilingual effects across any language pair. PMID:28603576

  1. Bimodal control of fear-coping strategies by CB₁ cannabinoid receptors.

    PubMed

    Metna-Laurent, Mathilde; Soria-Gómez, Edgar; Verrier, Danièle; Conforzi, Martina; Jégo, Pierrick; Lafenêtre, Pauline; Marsicano, Giovanni

    2012-05-23

    To maximize their chances of survival, animals need to rapidly and efficiently respond to aversive situations. These responses can be classified as active or passive and depend on the specific nature of threats, but also on individual fear coping styles. In this study, we show that the control of excitatory and inhibitory brain neurons by type-1 cannabinoid (CB₁) receptors is a key determinant of fear coping strategies in mice. In classical fear conditioning, a switch between initially predominant passive fear responses (freezing) and active behaviors (escape attempts and risk assessment) develops over time. Constitutive genetic deletion of CB₁ receptors in CB₁⁻/⁻ mice disrupted this pattern by favoring passive responses. This phenotype can be ascribed to endocannabinoid control of excitatory neurons, because it was reproduced in conditional mutant mice lacking CB₁ receptors from cortical glutamatergic neurons. CB₁ receptor deletion from GABAergic brain neurons led to the opposite phenotype, characterized by the predominance of active coping. The CB₁ receptor agonist Δ⁹-tetrahydrocannabinol exerted a biphasic control of fear coping strategies, with lower and higher doses favoring active and passive responses, respectively. Finally, viral re-expression of CB₁ receptors in the amygdala of CB₁⁻/⁻ mice restored the normal switch between the two coping strategies. These data strongly suggest that CB₁ receptor signaling bimodally controls the spontaneous adoption of active or passive coping strategies in individuals. This primary function of the endocannabinoid system in shaping individual behavioral traits should be considered when studying the mechanisms of physiological and pathological fear.

  2. NERVA-Derived Concept for a Bimodal Nuclear Thermal Rocket

    SciTech Connect

    Fusselman, Steven P.; Frye, Patrick E.; Gunn, Stanley V.; Morrison, Calvin Q.; Borowski, Stanley K.

    2005-02-06

    The Nuclear Thermal Rocket is an enabling technology for human exploration missions. The 'bimodal' NTR (BNTR) provides a novel approach to meeting both propulsion and power requirements of future manned and robotic missions. The purpose of this study was to evaluate tie-tube cooling configurations, NTR performance, Brayton cycle performance, and LOX-Augmented NTR (LANTR) feasibility to arrive at a point of departure BNTR configuration for subsequent system definition.

  3. Fluoride-assisted synthesis of bimodal microporous SSZ-13 zeolite.

    PubMed

    Zhu, Xiaochun; Kosinov, Nikolay; Hofmann, Jan P; Mezari, Brahim; Qian, Qingyun; Rohling, Roderigh; Weckhuysen, Bert M; Ruiz-Martínez, Javier; Hensen, Emiel J M

    2016-02-21

    The presence of small amount of fluoride in alkaline hydrothermal synthesis of SSZ-13 zeolite yields bimodal microporous particles with substantially improved performance in the methanol-to-olefins (MTO) reaction. Hydrocarbon uptake measurements and fluorescence microspectroscopy of spent catalysts demonstrate enhanced diffusion through micropores at the grain boundaries of nanocrystals running through the zeolite particles. Fluoride-assisted SSZ-13 synthesis is a cheap and scalable approach to optimize the performance of MTO zeolite catalysts.

  4. Bimodal effects of cinnamaldehyde and camphor on mouse TRPA1.

    PubMed

    Alpizar, Yeranddy A; Gees, Maarten; Sanchez, Alicia; Apetrei, Aurelia; Voets, Thomas; Nilius, Bernd; Talavera, Karel

    2013-06-01

    TRPA1 is a nonselective cation channel activated by a wide variety of noxious chemicals. Intriguingly, several TRPA1 modulators induce a bimodal effect, activating the channel at micromolar concentrations and inhibiting it at higher concentrations. Here we report the bimodal action of cinnamaldehyde (CA) and camphor, which are thus far reported as agonist and antagonist of TRPA1, respectively. Whole-cell patch-clamp experiments in TRPA1-expressing CHO cells revealed that, as previously reported, extracellular application of 100 μM CA strongly stimulates TRPA1 currents. However, subsequent application of 3 mM CA induced fast and reversible current inhibition. Application of 3 mM CA in basal conditions induced a rather small current increase, followed by current inhibition and a dramatic rebound of current amplitude upon washout. These observations are reminiscent of the effects of TRPA1 modulators having bimodal effects, e.g., menthol and nicotine. In line with previous reports, extracellular application of 1 mM camphor induced a decrease of basal TRPA1 currents. However, the current amplitude showed a significant overshoot upon washout. On the other hand, application of 100 μM camphor induced a 3-fold increase of the basal current amplitude measured at -75 mV. The bimodal effects of CA and camphor on TRPA1 were also observed in microfluorimetric measurements of intracellular Ca(2+) in intact TRPA1-expressing CHO cells and in primary cultures of mouse dorsal root ganglion neurons. These findings are essential for the understanding of the complex sensory properties of these compounds, as well as their utility when used to study the pathophysiological relevance of TRPA1.

  5. A Neonatal Bimodal MR-CT Head Template

    PubMed Central

    Mohtasebi, Mehrana; Abrishami Moghaddam, Hamid; Grebe, Reinhard; Gity, Masoumeh; Wallois, Fabrice

    2017-01-01

    Neonatal MR templates are appropriate for brain structural analysis and spatial normalization. However, they do not provide the essential accurate details of cranial bones and fontanels-sutures. Distinctly, CT images provide the best contrast for bone definition and fontanels-sutures. In this paper, we present, for the first time, an approach to create a fully registered bimodal MR-CT head template for neonates with a gestational age of 39 to 42 weeks. Such a template is essential for structural and functional brain studies, which require precise geometry of the head including cranial bones and fontanels-sutures. Due to the special characteristics of the problem (which requires inter-subject inter-modality registration), a two-step intensity-based registration method is proposed to globally and locally align CT images with an available MR template. By applying groupwise registration, the new neonatal CT template is then created in full alignment with the MR template to build a bimodal MR-CT template. The mutual information value between the CT and the MR template is 1.17 which shows their perfect correspondence in the bimodal template. Moreover, the average mutual information value between normalized images and the CT template proposed in this study is 1.24±0.07. Comparing this value with the one reported in a previously published approach (0.63±0.07) demonstrates the better generalization properties of the new created template and the superiority of the proposed method for the creation of CT template in the standard space provided by MR neonatal head template. The neonatal bimodal MR-CT head template is freely downloadable from https://www.u-picardie.fr/labo/GRAMFC. PMID:28129340

  6. Depletion-induced structure and dynamics in bimodal colloidal suspensions.

    SciTech Connect

    Sikorski, M.; Sandy, A. R.; Narayanan, S.

    2011-05-03

    Combined small angle x-ray scattering and x-ray photon correlation spectroscopy studies of moderately concentrated bimodal hard-sphere colloidal suspensions in the fluid phase show that depletion-induced demixing introduces spatially heterogeneous dynamics with two distinct time scales. The adhesive nature, as well as the mobility, of the large particles is determined by the level of interaction within the monomodal domains. This interaction is driven by osmotic forces, which are governed by the relative concentration of the constituents.

  7. Paper-Based Bimodal Sensor for Electronic Skin Applications.

    PubMed

    Jung, Minhyun; Kim, Kyungkwan; Kim, Bumjin; Cheong, Haena; Shin, Kwanwoo; Kwon, Oh-Sun; Park, Jong-Jin; Jeon, Sanghun

    2017-08-16

    We present the development of a flexible bimodal sensor using a paper platform and inkjet printing method, which are suited for low-cost fabrication processes and realization of flexible devices. In this study, we employed a vertically stacked bimodal device architecture in which a temperature sensor is stacked on top of a pressure sensor and operated on different principles, allowing the minimization of interference effects. For the temperature sensor placed in the top layer, we used the thermoelectric effect and formed a closed-loop thermocouple composed of two different printable inks (conductive PEDOT:PSS and silver nanoparticles on a flexible paper platform) and obtained temperature-sensing capability over a wide range (150 °C). For the pressure sensor positioned in the bottom layer, we used microdimensional pyramid-structured poly(dimethylsiloxane) coated with multiwall carbon nanotube conducting ink. Our pressure sensor exhibits a high-pressure sensitivity over a wide range (100 Pa to 5 kPa) and high-endurance characteristics of 10(5). Our 5 × 5 bimodal sensor array demonstrates negligible interference, high-speed responsivity, and robust sensing characteristics. We believe that the material, process, two-terminal device, and integration scheme developed in this study have a great value that can be widely applied to electronic skin.

  8. Does bimodal stimulus presentation increase ERP components usable in BCIs?

    NASA Astrophysics Data System (ADS)

    Thurlings, Marieke E.; Brouwer, Anne-Marie; Van Erp, Jan B. F.; Blankertz, Benjamin; Werkhoven, Peter J.

    2012-08-01

    Event-related potential (ERP)-based brain-computer interfaces (BCIs) employ differences in brain responses to attended and ignored stimuli. Typically, visual stimuli are used. Tactile stimuli have recently been suggested as a gaze-independent alternative. Bimodal stimuli could evoke additional brain activity due to multisensory integration which may be of use in BCIs. We investigated the effect of visual-tactile stimulus presentation on the chain of ERP components, BCI performance (classification accuracies and bitrates) and participants’ task performance (counting of targets). Ten participants were instructed to navigate a visual display by attending (spatially) to targets in sequences of either visual, tactile or visual-tactile stimuli. We observe that attending to visual-tactile (compared to either visual or tactile) stimuli results in an enhanced early ERP component (N1). This bimodal N1 may enhance BCI performance, as suggested by a nonsignificant positive trend in offline classification accuracies. A late ERP component (P300) is reduced when attending to visual-tactile compared to visual stimuli, which is consistent with the nonsignificant negative trend of participants’ task performance. We discuss these findings in the light of affected spatial attention at high-level compared to low-level stimulus processing. Furthermore, we evaluate bimodal BCIs from a practical perspective and for future applications.

  9. Bimodality of stable and plastic traits in plants.

    PubMed

    Fisher, Josef; Bensal, Elad; Zamir, Dani

    2017-06-12

    We discovered an unexpected mode of bimodal distribution of stable and plastic traits, which was consistent for homologous traits of 32 varieties of seven species both in well-irrigated fields and dry conditions. We challenged archived genetic mapping data for 36 fruit, seed, flower and yield traits in tomato and found an unexpected bimodal distribution in one measure of trait variability, the mean coefficient of variation, with some traits being consistently more variable than others. To determine the degree of conservation of this distribution among higher plants, we compared 18 homologous phenotypes, including yield and seed production, across different crop species grown in a common 'crop garden' experiment. The set included 32 varieties of tomato, eggplant, pepper, melon, watermelon, sunflower and maize. Estimates of canalization were obtained using a 'canalization replication' experimental design that generated multiple estimates of the coefficient of variation of traits, as well as their reaction norms in optimal and water-stressed field plots. A common pattern of bimodal distribution of stable and plastic traits was observed for all the varieties and for a wild weed (Solanum nigrum). We propose that canalization profiles of traits in a variety of taxa were ancestrally selected to maximize adaptation and reproductive success.

  10. Bimodal Analysis of Mammary Epithelial Cell Migration in Two Dimensions

    PubMed Central

    Potdar, Alka A.; Lu, Jenny; Jeon, Junhwan; Weaver, Alissa M.; Cummings, Peter T.

    2013-01-01

    Cell migration paths of mammary epithelial cells (expressing different versions of the promigratory tyrosine kinase receptor Her2/Neu) were analyzed within a bimodal framework that is a generalization of the run-and-tumble description applicable to bacterial migration. The mammalian cell trajectories were segregated into two types of alternating modes, namely, the “directional-mode” (mode I, the more persistent mode, analogous to the bacterial run phase) and the “re-orientation-mode” (mode II, the less persistent mode, analogous to the bacterial tumble phase). Higher resolution (more pixel information, relative to cell size) and smaller sampling intervals (time between images) were found to give a better estimate of the deduced single cell dynamics (such as directional-mode time and turn angle distribution) of the various cell types from the bimodal analysis. The bimodal analysis tool permits the deduction of short-time dynamics of cell motion such as the turn angle distributions and turn frequencies during the course of cell migration compared to standard methods of cell migration analysis. We find that the two-hour mammalian cell tracking data do not fall into the diffusive regime implying that the often-used random motility expressions for mammalian cell motion (based on assuming diffusive motion) are invalid over the time steps (fraction of minute) typically used in modeling mammalian cell migration. PMID:18982450

  11. Does bimodal stimulus presentation increase ERP components usable in BCIs?

    PubMed

    Thurlings, Marieke E; Brouwer, Anne-Marie; Van Erp, Jan B F; Blankertz, Benjamin; Werkhoven, Peter J

    2012-08-01

    Event-related potential (ERP)-based brain-computer interfaces (BCIs) employ differences in brain responses to attended and ignored stimuli. Typically, visual stimuli are used. Tactile stimuli have recently been suggested as a gaze-independent alternative. Bimodal stimuli could evoke additional brain activity due to multisensory integration which may be of use in BCIs. We investigated the effect of visual-tactile stimulus presentation on the chain of ERP components, BCI performance (classification accuracies and bitrates) and participants' task performance (counting of targets). Ten participants were instructed to navigate a visual display by attending (spatially) to targets in sequences of either visual, tactile or visual-tactile stimuli. We observe that attending to visual-tactile (compared to either visual or tactile) stimuli results in an enhanced early ERP component (N1). This bimodal N1 may enhance BCI performance, as suggested by a nonsignificant positive trend in offline classification accuracies. A late ERP component (P300) is reduced when attending to visual-tactile compared to visual stimuli, which is consistent with the nonsignificant negative trend of participants' task performance. We discuss these findings in the light of affected spatial attention at high-level compared to low-level stimulus processing. Furthermore, we evaluate bimodal BCIs from a practical perspective and for future applications.

  12. Evidence for a bimodal distribution in human communication.

    PubMed

    Wu, Ye; Zhou, Changsong; Xiao, Jinghua; Kurths, Jürgen; Schellnhuber, Hans Joachim

    2010-11-02

    Interacting human activities underlie the patterns of many social, technological, and economic phenomena. Here we present clear empirical evidence from Short Message correspondence that observed human actions are the result of the interplay of three basic ingredients: Poisson initiation of tasks and decision making for task execution in individual humans as well as interaction among individuals. This interplay leads to new types of interevent time distribution, neither completely Poisson nor power-law, but a bimodal combination of them. We show that the events can be separated into independent bursts which are generated by frequent mutual interactions in short times following random initiations of communications in longer times by the individuals. We introduce a minimal model of two interacting priority queues incorporating the three basic ingredients which fits well the distributions using the parameters extracted from the empirical data. The model can also embrace a range of realistic social interacting systems such as e-mail and letter communications when taking the time scale of processing into account. Our findings provide insight into various human activities both at the individual and network level. Our analysis and modeling of bimodal activity in human communication from the viewpoint of the interplay between processes of different time scales is likely to shed light on bimodal phenomena in other complex systems, such as interevent times in earthquakes, rainfall, forest fire, and economic systems, etc.

  13. Evidence for a bimodal distribution in human communication

    PubMed Central

    Wu, Ye; Zhou, Changsong; Xiao, Jinghua; Kurths, Jürgen; Schellnhuber, Hans Joachim

    2010-01-01

    Interacting human activities underlie the patterns of many social, technological, and economic phenomena. Here we present clear empirical evidence from Short Message correspondence that observed human actions are the result of the interplay of three basic ingredients: Poisson initiation of tasks and decision making for task execution in individual humans as well as interaction among individuals. This interplay leads to new types of interevent time distribution, neither completely Poisson nor power-law, but a bimodal combination of them. We show that the events can be separated into independent bursts which are generated by frequent mutual interactions in short times following random initiations of communications in longer times by the individuals. We introduce a minimal model of two interacting priority queues incorporating the three basic ingredients which fits well the distributions using the parameters extracted from the empirical data. The model can also embrace a range of realistic social interacting systems such as e-mail and letter communications when taking the time scale of processing into account. Our findings provide insight into various human activities both at the individual and network level. Our analysis and modeling of bimodal activity in human communication from the viewpoint of the interplay between processes of different time scales is likely to shed light on bimodal phenomena in other complex systems, such as interevent times in earthquakes, rainfall, forest fire, and economic systems, etc. PMID:20959414

  14. Temporal integration by stochastic recurrent network dynamics with bimodal neurons.

    PubMed

    Okamoto, Hiroshi; Isomura, Yoshikazu; Takada, Masahiko; Fukai, Tomoki

    2007-06-01

    Temporal integration of externally or internally driven information is required for a variety of cognitive processes. This computation is generally linked with graded rate changes in cortical neurons, which typically appear during a delay period of cognitive task in the prefrontal and other cortical areas. Here, we present a neural network model to produce graded (climbing or descending) neuronal activity. Model neurons are interconnected randomly by AMPA-receptor-mediated fast excitatory synapses and are subject to noisy background excitatory and inhibitory synaptic inputs. In each neuron, a prolonged afterdepolarizing potential follows every spike generation. Then, driven by an external input, the individual neurons display bimodal rate changes between a baseline state and an elevated firing state, with the latter being sustained by regenerated afterdepolarizing potentials. When the variance of background input and the uniform weight of recurrent synapses are adequately tuned, we show that stochastic noise and reverberating synaptic input organize these bimodal changes into a sequence that exhibits graded population activity with a nearly constant slope. To test the validity of the proposed mechanism, we analyzed the graded activity of anterior cingulate cortex neurons in monkeys performing delayed conditional Go/No-go discrimination tasks. The delay-period activities of cingulate neurons exhibited bimodal activity patterns and trial-to-trial variability that are similar to those predicted by the proposed model.

  15. Bimodal Bilinguals Co-activate Both Languages during Spoken Comprehension

    PubMed Central

    Shook, Anthony; Marian, Viorica

    2012-01-01

    Bilinguals have been shown to activate their two languages in parallel, and this process can often be attributed to overlap in input between the two languages. The present study examines whether two languages that do not overlap in input structure, and that have distinct phonological systems, such as American Sign Language (ASL) and English, are also activated in parallel. Hearing ASL-English bimodal bilinguals’ and English monolinguals’ eye-movements were recorded during a visual world paradigm, in which participants were instructed, in English, to select objects from a display. In critical trials, the target item appeared with a competing item that overlapped with the target in ASL phonology. Bimodal bilinguals looked more at competing items than at phonologically unrelated items, and looked more at competing items relative to monolinguals, indicating activation of the sign-language during spoken English comprehension. The findings suggest that language co-activation is not modality specific, and provide insight into the mechanisms that may underlie cross-modal language co-activation in bimodal bilinguals, including the role that top-down and lateral connections between levels of processing may play in language comprehension. PMID:22770677

  16. Word Associations of Students at Predominantly White and Predominantly Black Colleges.

    ERIC Educational Resources Information Center

    Campbell, Joel T.; Belcher, Leon H.

    This study compared word association responses for college students in three geographic areas from four different kinds of colleges: (1) selective predominantly white colleges, (2) less selective predominantly white colleges, (3) selective predominantly black colleges, and (4) less selective predominantly black colleges. Stimulus words were chosen…

  17. Multifractal Characteristics of Bimodal Mercury Pore Size Distribution Curves

    NASA Astrophysics Data System (ADS)

    dos Santos Bonini, C.; Alves, M. C.; Paz González, A.

    2012-04-01

    Characterization of Hg pore size distribution (PSDs) curves by monofractal or multifractal analysis has been demonstrated to be an useful tool, which allows a better understanding of the organization of the soil pore space. There are also evidences that multiscale analysis of different segments found in bimodal pore size distributions measured by Hg intrusion can provide further valuable information. In this study we selected bimodal PSDs from samples taken from an experimental area in São Paulo state, Brazil, where a revegetation trial was set up over saprolitic material. The saprolite was left abandoned after decapitation of an Oxisol for building purposes. The field trial consisted of various treatments with different grass species and amendments. Pore size distribution of the sampled aggregates was measured in the equivalent diameter range from 0.005 to about 50 μm and it was characterized by a bimodal pattern, so that two compartments, i.e. 0.005 to 0.2 μm and 0.2 to 50 μm, could be distinguished. The multifractal theory was used to analyse both segments. The scaling properties of these two segments could be fitted reasonably well with multifractal models. Multifractal parameters obtained for equivalent diameters for the segments > 0.2 and < 0.2 μm showed great differences. For example, entropy dimension, D1, values from the segment 0.005-0.2 μm were always lower than those for the segment 0.2-50 μm form NDI , whereas the Hólder exponent of order zero, α0, were higher for the former segment. These results indicate the probability different degrees of heterogeneity within the Hg pore size distributions studied.

  18. Bimodal and Gaussian Ising spin glasses in dimension two

    NASA Astrophysics Data System (ADS)

    Lundow, P. H.; Campbell, I. A.

    2016-02-01

    An analysis is given of numerical simulation data to size L =128 on the archetype square lattice Ising spin glasses (ISGs) with bimodal (±J ) and Gaussian interaction distributions. It is well established that the ordering temperature of both models is zero. The Gaussian model has a nondegenerate ground state and thus a critical exponent η ≡0 , and a continuous distribution of energy levels. For the bimodal model, above a size-dependent crossover temperature T*(L ) there is a regime of effectively continuous energy levels; below T*(L ) there is a distinct regime dominated by the highly degenerate ground state plus an energy gap to the excited states. T*(L ) tends to zero at very large L , leaving only the effectively continuous regime in the thermodynamic limit. The simulation data on both models are analyzed with the conventional scaling variable t =T and with a scaling variable τb=T2/(1 +T2) suitable for zero-temperature transition ISGs, together with appropriate scaling expressions. The data for the temperature dependence of the reduced susceptibility χ (τb,L ) and second moment correlation length ξ (τb,L ) in the thermodynamic limit regime are extrapolated to the τb=0 critical limit. The Gaussian critical exponent estimates from the simulations, η =0 and ν =3.55 (5 ) , are in full agreement with the well-established values in the literature. The bimodal critical exponents, estimated from the thermodynamic limit regime analyses using the same extrapolation protocols as for the Gaussian model, are η =0.20 (2 ) and ν =4.8 (3 ) , distinctly different from the Gaussian critical exponents.

  19. Insights Into Magma Mixing from Bimodal Volcanic Centers

    NASA Astrophysics Data System (ADS)

    Hudgins, T.

    2016-12-01

    Magma mixing has been described as ubiquitous by some, and unlikely by others. Intermediate magmas in arc environments are oft attributed to magma mixing, however critics of magma mixing point to bimodal volcanic centers as evidence that magma mixing is not a plausible mechanism to generate intermediate magmas, given the large volumes of mafic and felsic lavas and the absence of intermediate lavas. Here we present a model that investigates the physical plausibility of mixing mafic and felsic magmas at bimodal volcanic centers. To do this we utilize the chemical and thermodynamic output of MELTS (Ghiorso and Sack, 1995) to constrain the changes in chemistry, crystallinity, viscosity, and enthalpy for mafic and felsic lavas erupted from the Trans-Mexican Volcanic Belt. The Trans-Mexican Volcanic Belt is an ideal place for this investigation as it erupted abundant mafic and felsic lavas from 7.5 - 3.0 Ma and has been well studied, providing a wealth of well characterized samples to work with. Using the MELTS output of these data we can assess under what conditions the viscosities (η) of the mafic and felsic magmas satisfy the experimentally constrained Δlog η (log(ηmafic/ηfelsic)) < 0.5 threshold for mixing. Variations between magma chamber conditions such as pressure, temperature, and composition in the Trans-Mexican Volcanic Belt and volcanic centers where mixing is proposed and has been modeled (e.g. Mt. Hood, Oregon; Mutnovsky, Kamchatka) are used to provide insight into why intermediate lavas are not present in bimodal volcanic centers.

  20. Bimodal Fission in the Skyrme-Hartree-Fock Approach

    SciTech Connect

    Staszczak, A.; Dobaczewski, J.; Nazarewicz, Witold

    2007-01-01

    Spontaneous fission properties of 256Fm, 258Fm, and 260Fm isotopes are studied within the Skyrme-Hartree-Fock+BCS framework. In the particle-hole channel we take the Skyrme SkM* effective force, while in the particle-particle channel we employ the seniority pairing interaction. Three static fission paths for all investigated heavy fermium isotopes are found. The analysis of these fission modes allows to describe observed asymmetric fission of 256Fm, as well as bimodal fission of 258Fm and symmetric fission in 260Fm.

  1. Determining surface properties with bimodal and multimodal AFM.

    PubMed

    Forchheimer, D; Borysov, Stanislav S; Platz, D; Haviland, David B

    2014-12-05

    Conventional dynamic atomic force microscopy (AFM) can be extended to bimodal and multimodal AFM in which the cantilever is simultaneously excited at two or more resonance frequencies. Such excitation schemes result in one additional amplitude and phase images for each driven resonance, and potentially convey more information about the surface under investigation. Here we present a theoretical basis for using this information to approximate the parameters of a tip-surface interaction model. The theory is verified by simulations with added noise corresponding to room-temperature measurements.

  2. Behavioral measures of multisensory integration: bounds on bimodal detection probability.

    PubMed

    Colonius, Hans

    2015-01-01

    One way to test and quantify multisensory integration in a behavioral paradigm is to compare bimodal detection probability with bounds defined by some combination of the unimodal detection probabilities. Here we (1) improve on an upper bound recently suggested by Stevenson et al. (Brain Topogr 27(6):707-730, 2014), (2) present a lower bound, (3) interpret the bounds in terms of stochastic dependency between the detection probabilities, (4) discuss some additional assumptions required for the validity of any such bound, (5) suggest some potential applications to neurophysiologic measures, and point out some parallels to the 'race model inequality' for reaction times.

  3. Bimodality: a sign of critical behavior in nuclear reactions.

    PubMed

    Le Fèvre, A; Aichelin, J

    2008-02-01

    The recently discovered coexistence of multifragmentation and residue production for the same total transverse energy of light charged particles, which has been dubbed bimodality like it has been introduced in the framework of equilibrium thermodynamics, can be well reproduced in numerical simulations of heavy ion reactions. A detailed analysis shows that fluctuations (introduced by elementary nucleon-nucleon collisions) determine which of the exit states is realized. Thus, we can identify bifurcation in heavy ion reactions as a critical phenomenon. Also the scaling of the coexistence region with beam energy is well reproduced in these results from the quantum molecular dynamics simulation program.

  4. Nuclear markers, mitochondrial DNA and male secondary sexual traits variation in a newt hybrid zone (Triturus vulgaris x T. montandoni).

    PubMed

    Babik, W; Szymura, J M; Rafiński, J

    2003-07-01

    The smooth and the Montandon's newts (Triturus vulgaris and T. montandoni) are genetically similar sister species with highly divergent male secondary sexual traits involved in complex courtship behaviour. Their parapatric ranges overlap at moderate elevations in the Carpathian Mountains where they hybridize readily. Here we present a detailed study of genetic and morphological variation in populations from the area of sympatry. Analysis of variation at seven nuclear markers, mtDNA and male sexual secondary traits was complemented with an ecological survey of breeding sites characteristics. Extensive hybridization was revealed with back-cross individuals similar to either parental species predominating among hybrids. The hybrid zone exhibited a mosaic pattern: the genetic composition of the populations was correlated only weakly with their geographical position. No association with habitat type was found. Departures from Hardy-Weinberg proportions, significant linkage disequilibria and bimodal distribution of genotypes suggest strongly that assortative mating is an important factor shaping the genetic composition of hybrid populations. The pattern of cytonuclear disequilibria did not indicate much asymmetry in interspecific matings. Changes in the frequency of nuclear markers were highly concordant, whereas mtDNA showed much wider bidirectional introgression with 14% excess of T. montandoni haplotype. We argue that the mosaic structure of the newt hybrid zone results mainly from stochastic processes related to extinction and recolonization. Microgeographical differences in mtDNA introgression are explained by historical range shifts. Since morphologically intermediate males were underrepresented when compared to hybrid males identified by genetic markers, sexual selection acting against the morphological intermediates is implied. We discuss the implications of these findings in the context of reinforcement of prezygotic isolation in newts.

  5. Comparing perceived auditory width to the visual image of a performing ensemble in contrasting bi-modal environmentsa)

    PubMed Central

    Valente, Daniel L.; Braasch, Jonas; Myrbeck, Shane A.

    2012-01-01

    Despite many studies investigating auditory spatial impressions in rooms, few have addressed the impact of simultaneous visual cues on localization and the perception of spaciousness. The current research presents an immersive audiovisual environment in which participants were instructed to make auditory width judgments in dynamic bi-modal settings. The results of these psychophysical tests suggest the importance of congruent audio visual presentation to the ecological interpretation of an auditory scene. Supporting data were accumulated in five rooms of ascending volumes and varying reverberation times. Participants were given an audiovisual matching test in which they were instructed to pan the auditory width of a performing ensemble to a varying set of audio and visual cues in rooms. Results show that both auditory and visual factors affect the collected responses and that the two sensory modalities coincide in distinct interactions. The greatest differences between the panned audio stimuli given a fixed visual width were found in the physical space with the largest volume and the greatest source distance. These results suggest, in this specific instance, a predominance of auditory cues in the spatial analysis of the bi-modal scene. PMID:22280585

  6. [Diagnosis of trigeminal neuralgia predominantly of central and predominantly of peripheral origin].

    PubMed

    Grechko, V E; Puzin, M N

    1985-01-01

    The authors examined electrical conductivity of acupuncture points on the face of 60 patients with trigeminal neuralgia. The results permitted the development of differential diagnostic criteria of trigeminal neuralgia of predominantly central and predominantly peripheral genesis.

  7. Tie Tube Heat Transfer Modeling for Bimodal Nuclear Thermal Rockets

    SciTech Connect

    Clough, Joshua A.; Starkey, Ryan P.; Lewis, Mark J.; Lavelle, Thomas M.

    2007-01-30

    Bimodal nuclear thermal rocket systems have been shown to reduce the weight and cost of space vehicles to Mars and beyond by utilizing the reactor for power generation in the relatively long duration between burns in an interplanetary trajectory. No information, however, is available regarding engine and reactor-level operation of such bimodal systems. The purpose of this project is to generate engine and reactor models with sufficient fidelity and flexibility to accurately study the component-level effects of operating a propulsion-designed reactor at power generation levels. Previous development of a 1-D reactor and tie tube model found that ignoring heat generation inside of the tie tube leads to under-prediction of the temperature change and over-prediction of pressure change across the tie tube. This paper will present the development and results of a tie tube model that has been extended to account for heat generation, specifically in the moderator layer. This model is based on a 1-D distribution of power in the fuel elements and tie tubes, as a precursor to an eventual neutron-driven reactor model.

  8. Rats Display a Robust Bimodal Preference Profile for Sucralose

    PubMed Central

    Loney, Gregory C.; Torregrossa, Ann-Marie; Smith, James C.; Sclafani, Anthony

    2011-01-01

    Female Sprague–Dawley rats display considerable variability in their preference for the artificial sweetener sucralose over water. While some rats can be classified as sucralose preferrers (SP), as they prefer sucralose across a broad range of concentrations, others can be classified as sucralose avoiders (SA), as they avoid sucralose at concentrations above 0.1 g/L. Here, we expand on a previous report of this phenomenon by demonstrating, in a series of 2-bottle 24-h preference tests involving water and an ascending series of sucralose concentrations, that this variability in sucralose preference is robust across sex, stage of the estrous cycle, and 2 rat strains (Long–Evans and Sprague–Dawley). In a second experiment involving a large sample of rats (n = 50), we established that the ratio of SP to SA is approximately 35–65%. This bimodal behavioral response to sucralose appears to be driven by taste because rats display a similar bimodal licking response to a range of sucralose solutions presented during brief-access tests. Finally, we have shown that sucralose avoidance is extremely robust as 23-h water-deprived SA continue to avoid sucralose in 1-h single-bottle intake tests. Based on their reduced licking responses to sucralose during brief-access (taste driven) tests, and the fact that their distaste for sucralose cannot be overcome by the motivation to rehydrate, we conclude that SA detect a negative taste quality of sucralose that SP are relatively insensitive to. PMID:21653913

  9. Rats display a robust bimodal preference profile for sucralose.

    PubMed

    Loney, Gregory C; Torregrossa, Ann-Marie; Smith, James C; Sclafani, Anthony; Eckel, Lisa A

    2011-10-01

    Female Sprague-Dawley rats display considerable variability in their preference for the artificial sweetener sucralose over water. While some rats can be classified as sucralose preferrers (SP), as they prefer sucralose across a broad range of concentrations, others can be classified as sucralose avoiders (SA), as they avoid sucralose at concentrations above 0.1 g/L. Here, we expand on a previous report of this phenomenon by demonstrating, in a series of 2-bottle 24-h preference tests involving water and an ascending series of sucralose concentrations, that this variability in sucralose preference is robust across sex, stage of the estrous cycle, and 2 rat strains (Long-Evans and Sprague-Dawley). In a second experiment involving a large sample of rats (n = 50), we established that the ratio of SP to SA is approximately 35-65%. This bimodal behavioral response to sucralose appears to be driven by taste because rats display a similar bimodal licking response to a range of sucralose solutions presented during brief-access tests. Finally, we have shown that sucralose avoidance is extremely robust as 23-h water-deprived SA continue to avoid sucralose in 1-h single-bottle intake tests. Based on their reduced licking responses to sucralose during brief-access (taste driven) tests, and the fact that their distaste for sucralose cannot be overcome by the motivation to rehydrate, we conclude that SA detect a negative taste quality of sucralose that SP are relatively insensitive to.

  10. Movement, drivers and bimodality of the South Asian High

    NASA Astrophysics Data System (ADS)

    Nützel, Matthias; Dameris, Martin; Garny, Hella

    2016-11-01

    The South Asian High (SAH) is an important component of the summer monsoon system in Asia. In this study we investigate the location and drivers of the SAH at 100 hPa during the boreal summers of 1979 to 2014 on interannual, seasonal and synoptic timescales using seven reanalyses and observational data. Our comparison of the different reanalyses focuses especially on the bimodality of the SAH, i.e. the two preferred modes of the SAH centre location: the Iranian Plateau to the west and the Tibetan Plateau to the east. We find that only the National Centers for Environmental Prediction-National Center of Atmospheric Research (NCEP-NCAR) reanalysis shows a clear bimodal structure of the SAH centre distribution with respect to daily and pentad (5 day) mean data. Furthermore, the distribution of the SAH centre location is highly variable from year to year. As in simple model studies, which connect the SAH to heating in the tropics, we find that the mean seasonal cycle of the SAH and its centre are dominated by the expansion of convection in the South Asian region (70-130° E × 15-30° N) on the south-eastern border of the SAH. A composite analysis of precipitation and outgoing long-wave radiation data with respect to the location of the SAH centre reveals that a more westward (eastward) location of the SAH is related to stronger (weaker) convection and rainfall over India and weaker (stronger) precipitation over the western Pacific.

  11. Bimodal biometrics based on a representation and recognition approach

    NASA Astrophysics Data System (ADS)

    Xu, Yong; Zhong, Aini; Yang, Jian; Zhang, David

    2011-03-01

    It has been demonstrated that multibiometrics can produce higher accuracy than single biometrics. This is mainly because the use of multiple biometric traits of the subject enables more information to be used for identification or verification. In this paper, we focus on bimodal biometrics and propose a novel representation and recognition approach to bimodal biometrics. This approach first denotes the biometric trait sample by a complex vector. Then, it represents the test sample through the training samples and classifies the test sample as follows: let the test sample be expressed as a linear combination of all the training samples each being a complex vector. The proposed approach obtains the solution by solving a linear system. After evaluating the effect, in representing the test sample of each class, the approach classifies the test sample into the class that makes the greatest effect. The approach proposed is not only novel but also simple and computationally efficient. A large number of experiments show that our method can obtain promising results.

  12. Treating Nodular Lymphocyte Predominant Hodgkin Disease (NLPHD)

    MedlinePlus

    ... Lymphoma Treating Hodgkin Lymphoma Treating Nodular Lymphocytic Predominant Hodgkin Lymphoma (NLPHL) Because this rare type of Hodgkin ... Children Treating Hodgkin Lymphoma in Pregnancy More In Hodgkin Lymphoma About Hodgkin Lymphoma Causes, Risk Factors, and ...

  13. Silica micro/nanospheres for theranostics: from bimodal MRI and fluorescent imaging probes to cancer therapy

    PubMed Central

    Walia, Shanka

    2015-01-01

    Summary Nano-theranostics offer remarkable potential for future biomedical technology with simultaneous applications for diagnosis and therapy of disease sites. Through smart and careful chemical modifications of the nanoparticle surface, these can be converted to multifunctional tiny objects which in turn can be used as vehicle for delivering multimodal imaging agents and therapeutic material to specific target sites in vivo. In this sense, bimodal imaging probes that simultaneously enable magnetic resonance imaging and fluorescence imaging have gained tremendous attention because disease sites can be characterized quick and precisely through synergistic multimodal imaging. But such hybrid nanocomposite materials have limitations such as low chemical stability (magnetic component) and harsh cytotoxic effects (fluorescent component) and, hence, require a biocompatible protecting agent. Silica micro/nanospheres have shown promise as protecting agent due to the high stability and low toxicity. This review will cover a full description of MRI-active and fluorescent multifunctional silica micro/nanospheres including the design of the probe, different characterization methods and their application in imaging and treatment in cancer. PMID:25821696

  14. The bimodal theory of plasticity: A form-invariant generalisation

    NASA Astrophysics Data System (ADS)

    Soldatos, Kostas P.

    2011-08-01

    The bimodal plasticity model of fibre-reinforced materials is currently available and applicable only in association with thin-walled fibrous composites containing a family of straight fibres which are conveniently assumed parallel with the x1-axis of an appropriately chosen Cartesian co-ordinate system. Based on reliable experimental evidence, the model suggests that plastic slip in the composite operates in two distinct modes; the so-called matrix dominated mode (MDM) which depends on a matrix yield stress, and the fibre dominated mode (FDM) which depends also on the fibre yield stress. Each mode is activated by different states of applied stress, has its own yield surface (or surfaces) in the stress space and has its own segment on the overall yield surface of the composite. This paper employs theory of tensor representations and produces a form-invariant generalisation of both modes of the model. This generalisation furnishes the model with direct applicability to relevant plasticity problems, regardless of the shape of the fibres or the orientation of the co-ordinate system. It thus provides a proper mathematical foundation that underpins important physical concepts associated with the model while it also elucidates several technical relevant issues. A most interesting of those issues is the revelation that activation of the MDM plastic regime is possible only if the applied stress state allows the fibres to act like they are practically inextensible. Moreover, activation of the more dominant, between the two MDM plastic slip branches is possible only if conditions of material incompressibility hold, in addition to the implied condition of fibre inextensibility. A direct mathematical connection is thus achieved between basic, experimentally verified concepts of the bimodal plasticity model and a relevant mathematical model originated earlier from the theory of ideal fibre-reinforced materials. An additional issue of discussion involves the number of

  15. Speech Recognition of Bimodal Cochlear Implant Recipients Using a Wireless Audio Streaming Accessory for the Telephone.

    PubMed

    Wolfe, Jace; Morais, Mila; Schafer, Erin

    2016-02-01

    The goals of the present investigation were (1) to evaluate recognition of recorded speech presented over a mobile telephone for a group of adult bimodal cochlear implant users, and (2) to measure the potential benefits of wireless hearing assistance technology (HAT) for mobile telephone speech recognition using bimodal stimulation (i.e., a cochlear implant in one ear and a hearing aid on the other ear). A three-by-two-way repeated measures design was used to evaluate mobile telephone sentence-recognition performance differences obtained in quiet and in noise with and without the wireless HAT accessory coupled to the hearing aid alone, CI sound processor alone, and in the bimodal condition. Outpatient cochlear implant clinic. Sixteen bimodal users with Nucleus 24, Freedom, CI512, or CI422 cochlear implants participated in this study. Performance was measured with and without the use of a wireless HAT for the telephone used with the hearing aid alone, CI alone, and bimodal condition. CNC word recognition in quiet and in noise with and without the use of a wireless HAT telephone accessory in the hearing aid alone, CI alone, and bimodal conditions. Results suggested that the bimodal condition gave significantly better speech recognition on the mobile telephone with the wireless HAT. A wireless HAT for the mobile telephone provides bimodal users with significant improvement in word recognition in quiet and in noise over the mobile telephone.

  16. Gaze-independent ERP-BCIs: augmenting performance through location-congruent bimodal stimuli

    PubMed Central

    Thurlings, Marieke E.; Brouwer, Anne-Marie; Van Erp, Jan B. F.; Werkhoven, Peter

    2014-01-01

    Gaze-independent event-related potential (ERP) based brain-computer interfaces (BCIs) yield relatively low BCI performance and traditionally employ unimodal stimuli. Bimodal ERP-BCIs may increase BCI performance due to multisensory integration or summation in the brain. An additional advantage of bimodal BCIs may be that the user can choose which modality or modalities to attend to. We studied bimodal, visual-tactile, gaze-independent BCIs and investigated whether or not ERP components’ tAUCs and subsequent classification accuracies are increased for (1) bimodal vs. unimodal stimuli; (2) location-congruent vs. location-incongruent bimodal stimuli; and (3) attending to both modalities vs. to either one modality. We observed an enhanced bimodal (compared to unimodal) P300 tAUC, which appeared to be positively affected by location-congruency (p = 0.056) and resulted in higher classification accuracies. Attending either to one or to both modalities of the bimodal location-congruent stimuli resulted in differences between ERP components, but not in classification performance. We conclude that location-congruent bimodal stimuli improve ERP-BCIs, and offer the user the possibility to switch the attended modality without losing performance. PMID:25249947

  17. Bimodal Reading: Benefits of a Talking Computer for Average and Less Skilled Readers.

    ERIC Educational Resources Information Center

    Montali, Julie; Lewandowski, Lawrence

    1996-01-01

    Eighteen average readers and 18 less-skilled readers (grades 8 and 9) were presented with social studies and science passages via a computer either visually (on screen), auditorily (read by digitized voice), or bimodally (on screen, highlighted while being voiced). Less-skilled readers demonstrated comprehension in the bimodal condition equivalent…

  18. Assessing bimodality to detect the presence of a dual cognitive process.

    PubMed

    Freeman, Jonathan B; Dale, Rick

    2013-03-01

    Researchers have long sought to distinguish between single-process and dual-process cognitive phenomena, using responses such as reaction times and, more recently, hand movements. Analysis of a response distribution's modality has been crucial in detecting the presence of dual processes, because they tend to introduce bimodal features. Rarely, however, have bimodality measures been systematically evaluated. We carried out tests of readily available bimodality measures that any researcher may easily employ: the bimodality coefficient (BC), Hartigan's dip statistic (HDS), and the difference in Akaike's information criterion between one-component and two-component distribution models (AIC(diff)). We simulated distributions containing two response populations and examined the influences of (1) the distances between populations, (2) proportions of responses, (3) the amount of positive skew present, and (4) sample size. Distance always had a stronger effect than did proportion, and the effects of proportion greatly differed across the measures. Skew biased the measures by increasing bimodality detection, in some cases leading to anomalous interactive effects. BC and HDS were generally convergent, but a number of important discrepancies were found. AIC(diff) was extremely sensitive to bimodality and identified nearly all distributions as bimodal. However, all measures served to detect the presence of bimodality in comparison to unimodal simulations. We provide a validation with experimental data, discuss methodological and theoretical implications, and make recommendations regarding the choice of analysis.

  19. Knowledge Engineering Aspects of Affective Bi-Modal Educational Applications

    NASA Astrophysics Data System (ADS)

    Alepis, Efthymios; Virvou, Maria; Kabassi, Katerina

    This paper analyses the knowledge and software engineering aspects of educational applications that provide affective bi-modal human-computer interaction. For this purpose, a system that provides affective interaction based on evidence from two different modes has been developed. More specifically, the system's inferences about students' emotions are based on user input evidence from the keyboard and the microphone. Evidence from these two modes is combined by a user modelling component that incorporates user stereotypes as well as a multi criteria decision making theory. The mechanism that integrates the inferences from the two modes has been based on the results of two empirical studies that were conducted in the context of knowledge engineering of the system. The evaluation of the developed system showed significant improvements in the recognition of the emotional states of users.

  20. Bimodal star formation - Constraints from the solar neighborhood

    NASA Technical Reports Server (NTRS)

    Wyse, Rosemary F. G.; Silk, J.

    1987-01-01

    The chemical evolution resulting from a simple model of bimodal star formulation is investigated, using constraints from the solar neighborhood to set the parameters of the initial mass function and star formation rate. The two modes are an exclusively massive star mode, which forms stars at an exponentially declining rate, and a mode which contains stars of all masses and has a constant star formation rate. Satisfactory agreement with the age-metallicity relation for the thin disk and with the metallicity structure of the thin-disk and spheroid stars is possible only for a small range of parameter values. The preferred model offers a resolution to several of the long-standing problems of galactic chemical evolution, including explanations of the age-metallicity relation, the gas consumption time scale, and the stellar cumulative metallicity distributions.

  1. Stacked Gold Nanodisks for Bimodal Photoacoustic and Optical Coherence Imaging.

    PubMed

    Wi, Jung-Sub; Park, Jisoo; Kang, Heesung; Jung, Donggeun; Lee, Sang-Won; Lee, Tae Geol

    2017-06-27

    Herein, we report on biological imaging nanoprobes: physically synthesized gold nanodisks that have inherent optical advantages-a wide range of resonant wavelengths, tunable ratio of light absorption-to-scattering, and responsiveness to random incident light-due to their two-dimensional circular nanostructure. Based on our proposed physical synthesis where gold is vacuum deposited onto a prepatterned polymer template and released from the substrate in the form of a nanodisk, monodisperse two-dimensional gold nanodisks were prepared with independent control of their diameter and thickness. The optical benefits of the Au nanodisk were successfully demonstrated by the measurement of light absorbance of the nanodisks and the application of stacked nanodisks, where a smaller sized Au nanodisk was laid atop a larger nanodisk, as bimodal contrast agents for photoacoustic microscopy and optical coherence tomography.

  2. Use of nuclear energy for bimodal applications in space

    SciTech Connect

    Horn, F.L.; Powell, J.R.; Ludewig, H.

    1986-01-01

    The versatile bimodal nuclear reactor is proposed for producing space station-keeping power of 100's kW and also capable of bursts of power by ramping to 100's MW for short times to operate high power magnetic systems. The particle bed reactor, using half-millimeter diameter fuel particles immersed in coolant, provides the heat transfer capability needed for this power level. The coolant is a gas when directly coupled to a Brayton Cycle and is particularly responsive. The reactor design uses 37 fuel elements in a triangular pattern held in a cylindrical core. The reactor, radiator and turbo-generator are packaged for insertion into the shuttle cargo bay.

  3. Sedimentation field flow fractionation monitoring of bimodal wheat starch amylolysis.

    PubMed

    Salesse, C; Battu, S; Begaud-Grimaud, G; Cledat, D; Cook-Moreau, J; Cardot, P J P

    2006-10-06

    Enzymatic starch granule hydrolysis is one of the most important reactions in many industrial processes. In this study, we investigated the capacity of sedimentation field flow fractionation (SdFFF) to monitor the amylolysis of a bimodal starch population: native wheat starch. Results demonstrated a correlation between fractogram changes and enzymatic hydrolysis. Furthermore, SdFFF was used to sort sub-populations which enhanced the study of granule size distribution changes occurring during amylolysis. These results show the interest in coupling SdFFF with particle size measurement methods to study complex starch size/density modifications associated to hydrolysis. These results suggested different applications such as the association of SdFFF with structural investigations to better understand the specific mechanisms of amylolysis or starch granule structure.

  4. Bimodality of Latitudinal Gradients in Marine Species Richness.

    PubMed

    Chaudhary, Chhaya; Saeedi, Hanieh; Costello, Mark J

    2016-09-01

    The paradigm for the latitudinal gradient in species richness is that it is unimodal with a tropical peak. For 27 published studies, and global datasets of 65 000 recent and 50 000 fossil marine species, we found that almost all datasets were significantly bimodal with a dip in species richness near the equator. The locations of mid-latitude peaks varied between taxa and were higher in the northern hemisphere where the continental shelf is greatest. Our findings support hypotheses of tropical species evolving in response to temperature variation near the edges of the tropics and available high-productivity habitat. They suggest that the equator may already be too hot for some species and that the modes may move further apart due to climate warming.

  5. MRI Meets MPI: a bimodal MPI-MRI tomograph.

    PubMed

    Vogel, Patrick; Lother, Steffen; Rückert, Martin A; Kullmann, Walter H; Jakob, Peter M; Fidler, Florian; Behr, Volker C

    2014-10-01

    While magnetic particle imaging (MPI) constitutes a novel biomedical imaging technique for tracking superparamagnetic nanoparticles in vivo, unlike magnetic resonance imaging (MRI), it cannot provide anatomical background information. Until now these two modalities have been performed in separate scanners and image co-registration has been hampered by the need to reposition the sample in both systems as similarly as possible. This paper presents a bimodal MPI-MRI-tomograph that combines both modalities in a single system.MPI and MRI images can thus be acquired without moving the sample or replacing any parts in the setup. The images acquired with the presented setup show excellent agreement between the localization of the nanoparticles in MPI and the MRI background data. A combination of two highly complementary imaging modalities has been achieved.

  6. Impaired consciousness in partial seizures is bimodally distributed.

    PubMed

    Cunningham, Courtney; Chen, William C; Shorten, Andrew; McClurkin, Michael; Choezom, Tenzin; Schmidt, Christian P; Chu, Victoria; Bozik, Anne; Best, Cameron; Chapman, Melissa; Furman, Moran; Detyniecki, Kamil; Giacino, Joseph T; Blumenfeld, Hal

    2014-05-13

    To investigate whether impaired consciousness in partial seizures can usually be attributed to specific deficits in the content of consciousness or to a more general decrease in the overall level of consciousness. Prospective testing during partial seizures was performed in patients with epilepsy using the Responsiveness in Epilepsy Scale (n = 83 partial seizures, 30 patients). Results were compared with responsiveness scores in a cohort of patients with severe traumatic brain injury evaluated with the JFK Coma Recovery Scale-Revised (n = 552 test administrations, 184 patients). Standardized testing during partial seizures reveals a bimodal scoring distribution, such that most patients were either fully impaired or relatively spared in their ability to respond on multiple cognitive tests. Seizures with impaired performance on initial test items remained consistently impaired on subsequent items, while other seizures showed spared performance throughout. In the comparison group, we found that scores of patients with brain injury were more evenly distributed across the full range in severity of impairment. Partial seizures can often be cleanly separated into those with vs without overall impaired responsiveness. Results from similar testing in a comparison group of patients with brain injury suggest that the bimodal nature of Responsiveness in Epilepsy Scale scores is not a result of scale bias but may be a finding unique to partial seizures. These findings support a model in which seizures either propagate or do not propagate to key structures that regulate overall arousal and thalamocortical function. Future investigations are needed to relate these behavioral findings to the physiology underlying impaired consciousness in partial seizures.

  7. Impaired consciousness in partial seizures is bimodally distributed

    PubMed Central

    Cunningham, Courtney; Chen, William C.; Shorten, Andrew; McClurkin, Michael; Choezom, Tenzin; Schmidt, Christian P.; Chu, Victoria; Bozik, Anne; Best, Cameron; Chapman, Melissa; Furman, Moran; Detyniecki, Kamil; Giacino, Joseph T.

    2014-01-01

    Objective: To investigate whether impaired consciousness in partial seizures can usually be attributed to specific deficits in the content of consciousness or to a more general decrease in the overall level of consciousness. Methods: Prospective testing during partial seizures was performed in patients with epilepsy using the Responsiveness in Epilepsy Scale (n = 83 partial seizures, 30 patients). Results were compared with responsiveness scores in a cohort of patients with severe traumatic brain injury evaluated with the JFK Coma Recovery Scale–Revised (n = 552 test administrations, 184 patients). Results: Standardized testing during partial seizures reveals a bimodal scoring distribution, such that most patients were either fully impaired or relatively spared in their ability to respond on multiple cognitive tests. Seizures with impaired performance on initial test items remained consistently impaired on subsequent items, while other seizures showed spared performance throughout. In the comparison group, we found that scores of patients with brain injury were more evenly distributed across the full range in severity of impairment. Conclusions: Partial seizures can often be cleanly separated into those with vs without overall impaired responsiveness. Results from similar testing in a comparison group of patients with brain injury suggest that the bimodal nature of Responsiveness in Epilepsy Scale scores is not a result of scale bias but may be a finding unique to partial seizures. These findings support a model in which seizures either propagate or do not propagate to key structures that regulate overall arousal and thalamocortical function. Future investigations are needed to relate these behavioral findings to the physiology underlying impaired consciousness in partial seizures. PMID:24727311

  8. Globular Cluster Systems in Brightest Cluster Galaxies. III: Beyond Bimodality

    NASA Astrophysics Data System (ADS)

    Harris, William E.; Ciccone, Stephanie M.; Eadie, Gwendolyn M.; Gnedin, Oleg Y.; Geisler, Douglas; Rothberg, Barry; Bailin, Jeremy

    2017-01-01

    We present new deep photometry of the rich globular cluster (GC) systems around the Brightest Cluster Galaxies UGC 9799 (Abell 2052) and UGC 10143 (Abell 2147), obtained with the Hubble Space Telescope (HST) ACS and WFC3 cameras. For comparison, we also present new reductions of similar HST/ACS data for the Coma supergiants NGC 4874 and 4889. All four of these galaxies have huge cluster populations (to the radial limits of our data, comprising from 12,000 to 23,000 clusters per galaxy). The metallicity distribution functions (MDFs) of the GCs can still be matched by a bimodal-Gaussian form where the metal-rich and metal-poor modes are separated by ≃ 0.8 dex, but the internal dispersions of each mode are so large that the total MDF becomes very broad and nearly continuous from [Fe/H] ≃ ‑2.4 to solar. There are, however, significant differences between galaxies in the relative numbers of metal-rich clusters, suggesting that they underwent significantly different histories of mergers with massive gas-rich halos. Last, the proportion of metal-poor GCs rises especially rapidly outside projected radii R≳ 4 {R}{eff}, suggesting the importance of accreted dwarf satellites in the outer halo. Comprehensive models for the formation of GCs as part of the hierarchical formation of their parent galaxies will be needed to trace the systematic change in structure of the MDF with galaxy mass, from the distinctly bimodal form in smaller galaxies up to the broad continuum that we see in the very largest systems.

  9. Bimodal proton transfer in acid-base reactions in water

    SciTech Connect

    Rini, Matteo; Pines, Dina; Magnes, Ben-Zion; Pines, Ehud; Nibbering, Erik T.J.

    2004-11-15

    We investigate one of the fundamental reactions in solutions, the neutralization of an acid by a base. We use a photoacid, 8-hydroxy-1,3,6-trisulfonate-pyrene (HPTS; pyranine), which upon photoexcitation reacts with acetate under transfer of a deuteron (solvent: deuterated water). We analyze in detail the resulting bimodal reaction dynamics between the photoacid and the base, the first report on which was recently published [M. Rini, B.-Z. Magnes, E. Pines, and E. T. J. Nibbering, Science 301, 349 (2003)]. We have ascribed the bimodal proton-transfer dynamics to contributions from preformed hydrogen bonding complexes and from initially uncomplexed acid and base. We report on the observation of an additional (6 ps)-1 contribution to the reaction rate constant. As before, we analyze the slower part of the reaction within the framework of the diffusion model and the fastest part by a static, sub-150 fs reaction rate. Adding the second static term considerably improves the overall modeling of the experimental results. It also allows to connect experimentally the diffusion controlled bimolecular reaction models as defined by Eigen-Weller and by Collins-Kimball [D. Shoup and A. Szabo, Biophys. J. 40, 33 (1982)]. Our findings are in agreement with a three-stage mechanism for liquid phase intermolecular proton transfer: mutual diffusion of acid and base to form a 'loose' encounter complex, followed by reorganization of the solvent shells and by 'tightening' of the acid-base encounter complex. These rearrangements last a few picoseconds and enable a prompt proton transfer along the reaction coordinate, which occurs faster than our time resolution of 150 fs. Alternative models for the explanation of the slower 'on-contact' reaction time of the loose encounter complex in terms of proton transmission through a von Grotthuss mechanism are also discussed.

  10. "Bimodal" medical schools: excelling in research and primary care.

    PubMed

    Osborn, E H; O'Neil, E H

    1996-09-01

    The authors studied four "bimodal" medical schools--those ranked in the top 20% by the Association of American Medical Colleges both in production of primary care physicians and in receiving research grants from the National Institutes of Health. A descriptive, anthropologic method was used to describe the cultures of these schools and to determine common factors in their success. The four schools are at the University of Washington, the University of North Carolina, the University of California, San Francisco, and the University of California, San Diego. These common factors ranged from characteristics of the schools to characteristics of their external environments. All four are part of large, state-supported universities. They are relatively new schools in areas of the country that have blossomed in biotechnology, aerospace, and computer industries. The schools' missions, admission committees, and educational programs reflect their dual role: to meet the health care needs of their states and to advance basic science knowledge in medicine. Each state has a strong Academy of Family Practice, and the medical schools have been in the forefront of residency training in this specialty. Federal- and state-funded Area Health Education Centers and private foundations have provided seed money for educational programs in community and rural settings that attract medical students to primary care. Research-intensive medical schools can encourage students to enter primary care specialties if they have strong primary care leaders and programs and if they support medical education programs outside the academic, tertiary-care center. A culture of mutual respect and commitment to community service is also essential to achieving this bimodal success.

  11. Galaxy bimodality due to cold flows and shock heating

    NASA Astrophysics Data System (ADS)

    Dekel, Avishai; Birnboim, Yuval

    2006-05-01

    We address the origin of the robust bimodality observed in galaxy properties about a characteristic stellar mass ~3 × 1010Msolar. Less massive galaxies tend to be ungrouped blue star forming discs, while more massive galaxies are typically grouped red old-star spheroids. Colour-magnitude data show a gap between the red and blue sequences, extremely red luminous galaxies already at z~ 1, a truncation of today's blue sequence above L*, and massive starbursts at z~ 2-4. We propose that these features are driven by the thermal properties of the inflowing gas and their interplay with the clustering and feedback processes, all functions of the dark matter halo mass and associated with a similar characteristic scale. In haloes below a critical shock-heating mass Mshock<~ 1012Msolar, discs are built by cold streams, not heated by a virial shock, yielding efficient early star formation. It is regulated by supernova feedback into a long sequence of bursts in blue galaxies constrained to a `fundamental line'. Cold streams penetrating through hot media in M>=Mshock haloes preferentially at z>= 2 lead to massive starbursts in L > L* galaxies. At z < 2, in M > Mshock haloes hosting groups, the gas is heated by a virial shock, and being dilute it becomes vulnerable to feedback from energetic sources such as active galactic nuclei. This shuts off gas supply and prevents further star formation, leading by passive evolution to `red-and-dead' massive spheroids starting at z~ 1. A minimum in feedback efficiency near Mshock explains the observed minimum in M/L and the qualitative features of the star formation history. The cold flows provide a hint for solving the angular momentum problem. When these processes are incorporated in simulations they recover the main bimodality features and solve other open puzzles.

  12. Bimodal distribution of RNA expression levels in human skeletal muscle tissue

    PubMed Central

    2011-01-01

    Background Many human diseases and phenotypes are related to RNA expression, levels of which are influenced by a wide spectrum of genetic and exposure-related factors. In a large genome-wide study of muscle tissue expression, we found that some genes exhibited a bimodal distribution of RNA expression, in contrast to what is usually assumed in studies of a single healthy tissue. As bimodality has classically been considered a hallmark of genetic control, we assessed the genome-wide prevalence, cause, and association of this phenomenon with diabetes-related phenotypes in skeletal muscle tissue from 225 healthy Pima Indians using exon array expression chips. Results Two independent batches of microarrays were used for bimodal assessment and comparison. Of the 17,881 genes analyzed, eight (GSTM1, HLA-DRB1, ERAP2, HLA-DRB5, MAOA, ACTN3, NR4A2, and THNSL2) were found to have bimodal expression replicated in the separate batch groups, while 24 other genes had evidence of bimodality in only one group. Some bimodally expressed genes had modest associations with pre-diabetic phenotypes, of note ACTN3 with insulin resistance. Most of the other bimodal genes have been reported to be involved with various other diseases and characteristics. Association of expression with cis genetic variation in a subset of 149 individuals found all but one of the confirmed bimodal genes and nearly half of all potential ones to be highly significant expression quantitative trait loci (eQTL). The rare prevalence of these bimodally expressed genes found after controlling for batch effects was much lower than the prevalence reported in other studies. Additional validation in data from separate muscle expression studies confirmed the low prevalence of bimodality we observed. Conclusions We conclude that the prevalence of bimodal gene expression is quite rare in healthy muscle tissue (<0.2%), and is much lower than limited reports from other studies. The major cause of these clearly bimodal

  13. Monaural Beamforming in Bimodal Cochlear Implant Users: Effect of (A)symmetric Directivity and Noise Type

    PubMed Central

    Janssen, A. Miranda L.; Chalupper, Josef; Stokroos, Robert J.; George, Erwin L. J.

    2016-01-01

    Objective To evaluate monaural beamforming in bimodally aided cochlear implant (CI) users. Design The study enrolled twelve adult bimodal listeners with at least six months of CI-experience and using a contralateral hearing aid (HA) most of the daytime. Participants were uniformly fitted with the same CI speech processor and HA, giving access to an identical monaural beamformer in both ears. A within-subject repeated measures design evaluated three directional configurations [omnidirectional, asymmetric directivity (in CI alone) and symmetric directivity (in both CI and HA)] in two noise types [stationary and fluctuating]. Bimodal speech reception thresholds (SRT) as well as listening effort ratings were assessed in a diffuse noise field. Results Symmetric monaural beamforming provided a significant SRT improvement of 2.6 dB SNR, compared to 1.6 dB SNR for asymmetric monaural beamforming. Directional benefits were similarly observed in stationary and fluctuating noise. Directivity did not contribute to less listening effort in addition to improvement in speech intelligibility. Bimodal performance was about 7 dB SNR worse in fluctuating than in stationary noise. Conclusions Monaural beamforming provided substantial benefit for speech intelligibility in noise for bimodal listeners. The greatest benefit occurred when monaural beamforming was activated symmetrically in both CI and HA. Monaural beamforming does not bridge the gap between bimodal and normal hearing performance, especially in fluctuating noise. Results advocate further bimodal co-operation. Trial Registration This trial was registered in www.trialregister.nl under number NTR4901. PMID:27537075

  14. MMP1 bimodal expression and differential response to inflammatory mediators is linked to promoter polymorphisms

    PubMed Central

    2011-01-01

    Background Identifying the functional importance of the millions of single nucleotide polymorphisms (SNPs) in the human genome is a difficult challenge. Therefore, a reverse strategy, which identifies functionally important SNPs by virtue of the bimodal abundance across the human population of the SNP-related mRNAs will be useful. Those mRNA transcripts that are expressed at two distinct abundances in proportion to SNP allele frequency may warrant further study. Matrix metalloproteinase 1 (MMP1) is important in both normal development and in numerous pathologies. Although much research has been conducted to investigate the expression of MMP1 in many different cell types and conditions, the regulation of its expression is still not fully understood. Results In this study, we used a novel but straightforward method based on agglomerative hierarchical clustering to identify bimodally expressed transcripts in human umbilical vein endothelial cell (HUVEC) microarray data from 15 individuals. We found that MMP1 mRNA abundance was bimodally distributed in un-treated HUVECs and showed a bimodal response to inflammatory mediator treatment. RT-PCR and MMP1 activity assays confirmed the bimodal regulation and DNA sequencing of 69 individuals identified an MMP1 gene promoter polymorphism that segregated precisely with the MMP1 bimodal expression. Chromatin immunoprecipation (ChIP) experiments indicated that the transcription factors (TFs) ETS1, ETS2 and GATA3, bind to the MMP1 promoter in the region of this polymorphism and may contribute to the bimodal expression. Conclusions We describe a simple method to identify putative bimodally expressed RNAs from transcriptome data that is effective yet easy for non-statisticans to understand and use. This method identified bimodal endothelial cell expression of MMP1, which appears to be biologically significant with implications for inflammatory disease. (271 Words) PMID:21244711

  15. Characteristics of Entering Black Freshmen in Predominately Black and Predominately White Institutions: A Normative Report.

    ERIC Educational Resources Information Center

    Astin, Helen S.; Cross, Patricia H.

    Data tables are compiled on the characteristics of black freshmen entering a representative sanple of 393 predominately black and predominately white academic institutions. Using a ten percent random subsample of original data compiled by Alexander W. Astin for the Cooperative Institutional Research program, the researchers present extensive…

  16. Nodular lymphocyte-predominant Hodgkin lymphoma.

    PubMed

    Savage, Kerry J; Mottok, Anja; Fanale, Michelle

    2016-07-01

    Nodular lymphocyte-predominant Hodgkin lymphoma (NLPHL) is a rare subtype of Hodgkin lymphoma with distinct clinicopathologic features. It is typified by the presence of lymphocyte predominant (LP) cells, which are CD20(+) but CD15(-) and CD30(-) and are found scattered amongst small B lymphocytes arranged in a nodular pattern. Despite frequent and often late or multiple relapses, the prognosis of NLPHL is very favorable. There is an inherent risk of secondary aggressive non-Hodgkin lymphoma (NHL) and studies support that risk is highest in those with splenic involvement at presentation. Given disease rarity, the optimal management is unclear and opinions differ as to whether treatment paradigms should be similar to or differ from those for classical Hodgkin lymphoma (CHL). This review provides an overview of the existing literature describing pathological subtypes, outcome and treatment approaches for NLPHL.

  17. Gadolinium/terbium hybrid macromolecular complexes for bimodal imaging of atherothrombosis

    NASA Astrophysics Data System (ADS)

    Nghĩa, Nguyen Tráeng; Tinet, Eric; Ettori, Dominique; Beilvert, Anne; Pavon-Djavid, Graciela; Maire, Murielle; Ou, Phalla; Tualle, Jean-Michel; Chaubet, Frédéric

    2017-07-01

    We developed a fluorescence imaging microscope system intended for the localization within artery slices of a gadolinium-based macromolecular biospecific magnetic resonance (MR) contrast agent used for the visualization of atherothrombosis. As the contrast agent is not initially fluorescent, we substitute some gadolinium ions for terbium ions to make them fluorescent while preserving their chemical characteristics. A long fluorescence emission time constant enables us to have a suitable signal-to-noise ratio, despite a low intensity, using pulsed illumination and time-gated imaging. Images of rat arteries show that the contrast agent is indeed localized on the specific regions of the tissues. We currently have a tool that allows us to understand and optimize the MR contrast agent.

  18. THE BIMODAL METALLICITY DISTRIBUTION OF THE COOL CIRCUMGALACTIC MEDIUM AT z {approx}< 1

    SciTech Connect

    Lehner, N.; Howk, J. C.; Tripp, T. M.; Tumlinson, J.; Thom, C.; Fox, A. J.; Prochaska, J. X.; Werk, J. K.; Ribaudo, J.

    2013-06-20

    We assess the metal content of the cool ({approx}10{sup 4} K) circumgalactic medium (CGM) about galaxies at z {approx}< 1 using an H I-selected sample of 28 Lyman limit systems (LLS; defined here as absorbers with 16.2 {approx}< log N{sub H{sub I}} {approx}< 18.5) observed in absorption against background QSOs by the Cosmic Origins Spectrograph on board the Hubble Space Telescope. The N{sub H{sub I}} selection avoids metallicity biases inherent in many previous studies of the low-redshift CGM. We compare the column densities of weakly ionized metal species (e.g., O II, Si II, Mg II) to N{sub H{sub I}} in the strongest H I component of each absorber. We find that the metallicity distribution of the LLS (and hence the cool CGM) is bimodal with metal-poor and metal-rich branches peaking at [X/H] {approx_equal} -1.6 and -0.3 (or about 2.5% and 50% solar metallicities). The cool CGM probed by these LLS is predominantly ionized. The metal-rich branch of the population likely traces winds, recycled outflows, and tidally stripped gas; the metal-poor branch has properties consistent with cold accretion streams thought to be a major source of fresh gas for star forming galaxies. Both branches have a nearly equal number of absorbers. Our results thus demonstrate there is a significant mass of previously undiscovered cold metal-poor gas and confirm the presence of metal enriched gas in the CGM of z {approx}< 1 galaxies.

  19. Parallel language activation and inhibitory control in bimodal bilinguals

    PubMed Central

    Giezen, Marcel R.; Blumenfeld, Henrike K.; Shook, Anthony; Marian, Viorica; Emmorey, Karen

    2015-01-01

    Findings from recent studies suggest that spoken-language bilinguals engage nonlinguistic inhibitory control mechanisms to resolve cross-linguistic competition during auditory word recognition. Bilingual advantages in inhibitory control might stem from the need to resolve perceptual competition between similar-sounding words both within and between their two languages. If so, these advantages should be lessened or eliminated when there is no perceptual competition between two languages. The present study investigated the extent of inhibitory control recruitment during bilingual language comprehension by examining associations between language co-activation and nonlinguistic inhibitory control abilities in bimodal bilinguals, whose two languages do not perceptually compete. Cross-linguistic distractor activation was identified in the visual world paradigm, and correlated significantly with performance on a nonlinguistic spatial Stroop task within a group of 27 hearing ASL-English bilinguals. Smaller Stroop effects (indexing more efficient inhibition) were associated with reduced co-activation of ASL signs during the early stages of auditory word recognition. These results suggest that the role of inhibitory control in auditory word recognition is not limited to resolving perceptual linguistic competition in phonological input, but is also used to moderate competition that originates at the lexico-semantic level. PMID:25912892

  20. Investigating Interaural Frequency-Place Mismatches via Bimodal Vowel Integration

    PubMed Central

    Santurette, Sébastien; Chalupper, Josef; Dau, Torsten

    2014-01-01

    For patients having residual hearing in one ear and a cochlear implant (CI) in the opposite ear, interaural place-pitch mismatches might be partly responsible for the large variability in individual benefit. Behavioral pitch-matching between the two ears has been suggested as a way to individualize the fitting of the frequency-to-electrode map but is rather tedious and unreliable. Here, an alternative method using two-formant vowels was developed and tested. The interaural spectral shift was inferred by comparing vowel spaces, measured by presenting the first formant (F1) to the nonimplanted ear and the second (F2) on either side. The method was first evaluated with eight normal-hearing listeners and vocoder simulations, before being tested with 11 CI users. Average vowel distributions across subjects showed a similar pattern when presenting F2 on either side, suggesting acclimatization to the frequency map. However, individual vowel spaces with F2 presented to the implant did not allow a reliable estimation of the interaural mismatch. These results suggest that interaural frequency-place mismatches can be derived from such vowel spaces. However, the method remains limited by difficulties in bimodal fusion of the two formants. PMID:25421087

  1. Bimodal Gastroretentive Drug Delivery Systems of Lamotrigine: Formulation and Evaluation

    PubMed Central

    Poonuru, R. R.; Gonugunta, C. S. R

    2014-01-01

    Gastroretentive bimodal drug delivery systems of lamotrigine were developed using immediate release and extended release segments incorporated in a hydroxypropyl methylcellulose capsule and in vitro and in vivo evaluations were conducted. In vivo radiographic studies were carried out for the optimized formulation in healthy human volunteers with replacement of drug polymer complex by barium sulphate and the floating time was noted. Here the immediate release segment worked as loading dose and extended release segment as maintenance dose. The results of release studies of formulations with hydrophillic matrix to formulations with dual matrix hydroxypropyl methylcellulose acetate succinate shown that as the percentage of polymer increased, the release decreased. Selected formulation F2 having F-Melt has successfully released the drug within one hour and hydrophillic matrix composing polyethylene oxide with 5% hydroxypropyl methylcellulose acetate succinate showed a lag time of one hour and then extended its release up to 12th hour with 99.59% drug release following zero order kinetics with R2 value of 0.989. The Korsmeyer-Peppas equation showed the R2 value to be 0.941 and n value was 1.606 following non-Fickian diffusion pattern with supercase II relaxation mechanism. Here from extended release tablet the drug released slowly from the matrix while floating. PMID:25593380

  2. Bimodal activated carbons derived from resorcinol-formaldehyde cryogels

    PubMed Central

    Szczurek, Andrzej; Amaral-Labat, Gisele; Fierro, Vanessa; Pizzi, Antonio; Celzard, Alain

    2011-01-01

    Resorcinol-formaldehyde cryogels prepared at different dilution ratios have been activated with phosphoric acid at 450 °C and compared with their carbonaceous counterparts obtained by pyrolysis at 900 °C. Whereas the latter were, as expected, highly mesoporous carbons, the former cryogels had very different pore textures. Highly diluted cryogels allowed preparation of microporous materials with high surface areas, but activation of initially dense cryogels led to almost non-porous carbons, with much lower surface areas than those obtained by pyrolysis. The optimal acid concentration for activation, corresponding to stoichiometry between molecules of acid and hydroxyl groups, was 2 M l−1, and the acid–cryogel contact time also had an optimal value. Such optimization allowed us to achieve surface areas and micropore volumes among the highest ever obtained by activation with H3PO4, close to 2200 m2 g−1 and 0.7 cm3 g−1, respectively. Activation of diluted cryogels with a lower acid concentration of 1.2 M l−1 led to authentic bimodal activated carbons, having a surface area as high as 1780 m2 g−1 and 0.6 cm3 g−1 of microporous volume easily accessible through a widely developed macroporosity. PMID:27877405

  3. Nonlinear Pattern Selection in Bi-Modal Interfacial Instabilities

    NASA Astrophysics Data System (ADS)

    Picardo, Jason; Narayanan, Ranga

    2016-11-01

    We study the evolution of two interacting unstable interfaces, with the aim of understanding the role of non-linearity in pattern selection. Specifically, we consider two superposed thin films on a heated surface, that are susceptible to thermocapillary and Rayleigh-Taylor instabilities. Due to the presence of two unstable interfaces, the dispersion curve (linear growth rate plotted as a function of the perturbation wavelength) exhibits two peaks. If these peaks have equal heights, then the two corresponding disturbance patterns will grow with the same linear growth rate. Therefore, any selection between the two must occur via nonlinear effects. The two-interface problem under consideration provides a variety of such bi-modal situations, in which the role of nonlinearity in pattern selection is unveiled. We use a combination of long wave asymptotics, numerical simulations and amplitude expansions to understand the subtle nonlinear interactions between the two peak modes. Our results offer a counter-example to Rayleigh's principle of pattern formation, that the fastest growing linear mode will dominate the final pattern. Far from being governed by any such general dogma, the final selected pattern varies considerably from case to case. The authors acknowledge funding from NSF (0968313) and the Fulbright-Nehru fellowship.

  4. Investigating interaural frequency-place mismatches via bimodal vowel integration.

    PubMed

    Guérit, François; Santurette, Sébastien; Chalupper, Josef; Dau, Torsten

    2014-11-23

    For patients having residual hearing in one ear and a cochlear implant (CI) in the opposite ear, interaural place-pitch mismatches might be partly responsible for the large variability in individual benefit. Behavioral pitch-matching between the two ears has been suggested as a way to individualize the fitting of the frequency-to-electrode map but is rather tedious and unreliable. Here, an alternative method using two-formant vowels was developed and tested. The interaural spectral shift was inferred by comparing vowel spaces, measured by presenting the first formant (F1) to the nonimplanted ear and the second (F2) on either side. The method was first evaluated with eight normal-hearing listeners and vocoder simulations, before being tested with 11 CI users. Average vowel distributions across subjects showed a similar pattern when presenting F2 on either side, suggesting acclimatization to the frequency map. However, individual vowel spaces with F2 presented to the implant did not allow a reliable estimation of the interaural mismatch. These results suggest that interaural frequency-place mismatches can be derived from such vowel spaces. However, the method remains limited by difficulties in bimodal fusion of the two formants. © The Author(s) 2014.

  5. Effect of short range hydrodynamic on bimodal colloidal gel systems

    NASA Astrophysics Data System (ADS)

    Boromand, Arman; Jamali, Safa; Maia, Joao

    2015-03-01

    Colloidal Gels and disordered arrested systems has been studied extensively during the past decades. Although, they have found their place in multiple industries such as cosmetic, food and so on, their physical principals are still far beyond being understood. The interplay between different types of interactions from quantum scale, Van der Waals interaction, to short range interactions, depletion interaction, and long range interactions such as electrostatic double layer makes this systems challenging from simulation point of view. Many authors have implemented different simulation techniques such as molecular dynamics (MD) and Brownian dynamics (BD) to capture better picture during phase separation of colloidal system with short range attractive force. However, BD is not capable to include multi-body hydrodynamic interaction and MD is limited by the computational resources and is limited to short time and length scales. In this presentation we used Core-modified dissipative particle dynamics (CM-DPD) with modified depletion potential, as a coarse-grain model, to address the gel formation process in short ranged-attractive colloidal suspensions. Due to the possibility to include and separate short and long ranged-hydrodynamic forces in this method we studied the effect of each of those forces on the final morphology and report one of the controversial question in this field on the effect of hydrodynamics on the cluster formation process on bimodal, soft-hard colloidal mixtures.

  6. Quorum Sensing Desynchronization Leads to Bimodality and Patterned Behaviors

    PubMed Central

    Quan, David N.; Tsao, Chen-Yu; Wu, Hsuan-Chen; Bentley, William E.

    2016-01-01

    Quorum Sensing (QS) drives coordinated phenotypic outcomes among bacterial populations. Its role in mediating infectious disease has led to the elucidation of numerous autoinducers and their corresponding QS signaling pathways. Among them, the Lsr (LuxS-regulated) QS system is conserved in scores of bacteria, and its signal molecule, autoinducer-2 (AI-2), is synthesized as a product of 1-carbon metabolism. Lsr signal transduction processes, therefore, may help organize population scale activities in numerous bacterial consortia. Conceptions of how Lsr QS organizes population scale behaviors remain limited, however. Using mathematical simulations, we examined how desynchronized Lsr QS activation, arising from cell-to-cell population heterogeneity, could lead to bimodal Lsr signaling and fractional activation. This has been previously observed experimentally. Governing these processes are an asynchronous AI-2 uptake, where positive intracellular feedback in Lsr expression is combined with negative feedback between cells. The resulting activation patterns differ from that of the more widely studied LuxIR system, the topology of which consists of only positive feedback. To elucidate differences, both QS systems were simulated in 2D, where cell populations grow and signal each other via traditional growth and diffusion equations. Our results demonstrate that the LuxIR QS system produces an ‘outward wave’ of autoinduction, and the Lsr QS system yields dispersed autoinduction from spatially-localized secretion and uptake profiles. In both cases, our simulations mirror previously demonstrated experimental results. As a whole, these models inform QS observations and synthetic biology designs. PMID:27071007

  7. Development of Iron Doped Silicon Nanoparticles as Bimodal Imaging Agents

    PubMed Central

    Singh, Mani P.; Atkins, Tonya M.; Muthuswamy, Elayaraja; Kamali, Saeed; Tu, Chuqiao; Louie, Angelique Y.; Kauzlarich, Susan M.

    2012-01-01

    We demonstrate the synthesis of water-soluble allylamine terminated Fe doped Si (SixFe) nanoparticles as bimodal agents for optical and magnetic imaging. The preparation involves the synthesis of a single source iron containing precursor, Na4Si4 with x% Fe (x = 1, 5, 10), and its subsequent reaction with NH4Br to produce hydrogen terminated SixFe nanoparticles. The hydrogen-capped nanoparticles are further terminated with allylamine via thermal hydrosilylation. Transmission electron microscopy (TEM) indicates that the average particle diameter is ~3.0±1.0 nm. The Si5Fe nanoparticles show strong photoluminescence quantum yield in water (~ 10 %) with significant T2 contrast (r2/r1value of 4.31). Electron paramagnetic resonance (EPR) and Mössbauer spectroscopies indicate that iron in the nanoparticles is in the +3 oxidation state. Analysis of cytotoxicity using the resazurin assay on HepG2 liver cells indicates that the particles have minimal toxicity. PMID:22616623

  8. Options for enhanced performance of pellet bed reactor bimodal systems

    NASA Astrophysics Data System (ADS)

    Liscum-Powell, Jennifer; El-Genk, Mohamed S.

    1995-01-01

    Recently reported Bimodal Pellet Bed Reactor (BM-PeBR) system concepts utilize efficient Closed Brayton Cycle (CBC) engines and maintain the maximum fuel temperature almost constant below 1600 K during power and propulsion modes. Because the reactor thermal power is quite low, ranging from 44 kW to 176 kW for the 10 kWe and 40 kWe BM-PeBR, respectively, the propulsion performance parameters are modest: 3.5 and 16 N of thrust for these systems, respectively, at a specific impulse (Isp) of 750 s. This paper investigates the effect of increasing the reactor thermal power and maximum fuel temperature during the propulsion mode to improve the propulsion performance of these systems. Options considered include: (a) using ex-core heating versus in-core heating of the hydrogen propellant, and (b) ramping reactor thermal power in the propulsion mode versus operating at a constant thermal power level during both power and propulsion modes and radiating excess heat during power mode using a high temperature radiator. Results showed that with these options the 40 kWe BM-PeBR system can deliver 40 N to 212 N of thrust and corresponding Isp of 885 s and 760 s, respectively, when operating at a maximum fuel temperature of 2000 K. Similarly, the 10 kWe system can deliver a thrust of 2 N to 40 N at corresponding Isp of 860 and 740 s, respectively.

  9. Bimodal, Low Power Pellet Bed Reactor System Design Concept

    NASA Astrophysics Data System (ADS)

    El-Genk, Mohamed S.; Liscum-Powell, Jennifer; Pelaccio, Dennis G.

    1994-07-01

    A conceptual design is presented of a bimodal system that employs a pellet bed reactor heat source, helium-xenon Closed Brayton Cycle (CBC) engines, UC fuel, super-alloy structure materials, and hydrogen for propulsion operation. In addition to incorporating state-of-the-art, low risk technologies, and as much off-the-shelf hardware as possible in order to meet a near-term flight demonstration date, the system offers unique design and safety features. These design features include: (a) modularity to support a wide range of electric power and thermal propulsion requirements, (b) sectored, annular reactor core and multiple CBC engines for redundancy and to eliminate a single point failure in the coolant loop, (c) efficient CBC engines, (d) low maximum fuel temperature (<1600 K) that is maintained almost constant during power and propulsion modes, (e) spherical fuel mini-spheres or pellets that provide full retention of fission products and scalability to higher power levels, (f) two independent reactor control systems with built-in redundancy, (h) passive decay heat removal from the reactor core, (g) ground testing of the fully assembled system using electric heaters and unfueled mini-spheres or pellets, (h) negative temperature reactivity feedback for improved reactor operation and safety, (i) high specific impulse (650s-750s) and specific power (11.0- 21.9 We/kg), at relatively low power levels (10-40 kWe).

  10. The bimodal initial mass function in the Orion nebula cloud

    NASA Astrophysics Data System (ADS)

    Drass, H.; Haas, M.; Chini, R.; Bayo, A.; Hackstein, M.; Hoffmeister, V.; Godoy, N.; Vogt, N.

    2016-09-01

    Due to its youth, proximity and richness, the Orion nebula cloud (ONC) is an ideal testbed to obtain a comprehensive view on the initial mass function (IMF) down to the planetary mass regime. Using the HAWK-I camera at the VLT, we have obtained an unprecedented deep and wide near-infrared JHK mosaic of the ONC (90 per cent completeness at K ˜ 19.0 mag, 22 × 28 arcmin2). Applying the most recent isochrones and accounting for the contamination of background stars and galaxies, we find that ONC's IMF is bimodal with distinct peaks at about 0.25 and 0.025 M⊙ separated by a pronounced dip at the hydrogen burning limit (0.08 M⊙), with a depth of about a factor of 2-3 below the log-normal distribution. Apart from ˜920 low-mass stars (M < 1.4 M⊙) the IMF contains ˜760 brown dwarf candidates and ˜160 isolated planetary mass object candidates with M > 0.005 M⊙, hence about 10 times more substellar candidates than known before. The substellar IMF peak at 0.025 M⊙ could be caused by brown dwarfs and isolated planetary mass objects which have been ejected from multiple systems during the early star formation process or from circumstellar discs.

  11. Bimodal radio variability in OVRO-40 m-monitored blazars

    NASA Astrophysics Data System (ADS)

    Liodakis, I.; Pavlidou, V.; Hovatta, T.; Max-Moerbeck, W.; Pearson, T. J.; Richards, J. L.; Readhead, A. C. S.

    2017-06-01

    Blazars are known to show periods of quiescence followed by outbursts visible throughout the electromagnetic spectrum. We present a novel maximum likelihood approach to capture this bimodal behaviour by examining blazar radio variability in the flux-density domain. We separate quiescent and flaring components of a source's light curve by modelling its flux-density distribution as a series of 'off'- and 'on'-states. Our modelling allows us to extract information regarding the flaring ratio, duty cycle, and the modulation index in the 'off'-state, in the 'on'-state, as well as throughout the monitoring period of each blazar. We apply our method to a flux-density-limited subsample from the Owens Valley Radio Observatory's 15 GHz blazar monitoring programme, and explore differences in the variability characteristics between BL Lacs and FSRQs as well as between γ-ray detected and non-detected sources. We find that (1) BL Lacs are more variable and have relatively larger outbursts than the FSRQs; (2) unclassified blazar candidates in our sample show similar variability characteristics as the FSRQs and (3) γ-ray detected differ from the γ-ray non-detected sources in all their variability properties, suggesting a link between the production of γ-rays and the mechanism responsible for the radio variability. Finally, we fit distributions for blazar flaring ratios, duty cycles, and on- and off-modulation indices that can be used in population studies of variability-dependent blazar properties.

  12. Polyester scaffolds with bimodal pore size distribution for tissue engineering.

    PubMed

    Sosnowski, Stanislaw; Woźniak, Piotr; Lewandowska-Szumieł, Małgorzata

    2006-06-16

    This paper presents a method for the preparation of porous poly(L-lactide)/poly[(L-lactide)-co-glycolide] scaffolds for tissue engineering. Scaffolds were prepared by a mold pressing-salt leaching technique from structured microparticles. The total porosity was in the range 70-85%. The pore size distribution was bimodal. Large pores, susceptible for osteoblasts growth and proliferation had the dimensions 50-400 microm. Small pores, dedicated to the diffusion of nutrients or/and metabolites of bone forming cells, as well as the products of hydrolysis of polyesters from the walls of the scaffold, had sizes in the range 2 nm-5 microm. The scaffolds had good mechanical strength (compressive modulus equal to 41 MPa and a strength of 1.64 MPa for 74% porosity). Scaffolds were tested in vitro with human osteoblast-like cells (MG-63). It was found that the viability of cells seeded within the scaffolds obtained using the mold pressing-salt leaching technique from structured microparticles was better when compared to cells cultured in scaffolds obtained by traditional methods. After 34 d of culture, cells within the tested scaffolds were organized in a tissue-like structure. Photos of section of macro- and mesoporous PLLA/PLGA scaffold containing 50 wt.-% of PLGA microspheres after 34 d of culture. Dark spots mark MG-63 cells, white areas belong to the scaffold. The specimen was stained with haematoxylin/eosin. Bar = 100 microm.

  13. TURBULENCE IN GALAXY CLUSTER CORES: A KEY TO CLUSTER BIMODALITY?

    SciTech Connect

    Parrish, Ian J.; Sharma, Prateek; Quataert, Eliot

    2010-04-01

    We study the effects of externally imposed turbulence on the thermal properties of galaxy cluster cores, using three-dimensional numerical simulations including magnetic fields, anisotropic thermal conduction, and radiative cooling. The imposed 'stirring' crudely approximates the effects of galactic wakes, waves generated by galaxies moving through the intracluster medium, and/or turbulence produced by a central active galactic nucleus. The simulated clusters exhibit a strong bimodality. Modest levels of turbulence, {approx}100 km s{sup -1} {approx} 10% of the sound speed, suppress the heat-flux-driven buoyancy instability (HBI), resulting in an isotropically tangled magnetic field and a quasi-stable, high entropy, thermal equilibrium with no cooling catastrophe. Thermal conduction dominates the heating of the cluster core, but turbulent mixing is critical because it suppresses the HBI and (to a lesser extent) the thermal instability. Lower levels of turbulent mixing ({approx}<100 km s{sup -1}) are insufficient to suppress the HBI, rapidly leading to a thermal runaway and a cool-core cluster. Remarkably, then, small fluctuations in the level of turbulence in galaxy cluster cores can initiate transitions between cool-core (low entropy) and non-cool-core (high entropy) states.

  14. Hydrogen-resistant heat pipes for bimodal reactors

    SciTech Connect

    North, M.T.; Anderson, W.G.

    1997-01-01

    A sodium heat pipe that is tolerant of hydrogen permeation was developed for bimodal space power applications. Hydrogen permeation out of the heat pipe is enhanced by using a condenser design with a re-entrant annular gas cavity and an array of small diameter, thin-walled tubes to increase the permeation area. An experimental heat pipe with a nickel envelope was fabricated and tested. The heat pipe operated between 993K and 1073K, using sodium as the working fluid. During steady-state operation, hydrogen gas was injected into the heat pipe. The response of the heat pipe was monitored while the hydrogen permeated out of the heat pipe in the condenser section. For each of the tests run, the hydrogen gas was removed from the heat pipe in approximately 5 to 10 minutes. A model of the experimental heat pipe was developed to predict the enhancement in the hydrogen permeation rate out of the heat pipe. A significant improvement in the rate at which hydrogen permeates out of a heat pipe was predicted for the use of the special condenser geometry developed here. Agreement between the model and the experimental results was qualitatively good. Inclusion of the additional effects of fluid flow in the heat pipe are recommended for future work. {copyright} {ital 1997 American Institute of Physics.}

  15. Bimodal Biometric Verification Using the Fusion of Palmprint and Infrared Palm-Dorsum Vein Images

    PubMed Central

    Lin, Chih-Lung; Wang, Shih-Hung; Cheng, Hsu-Yung; Fan, Kuo-Chin; Hsu, Wei-Lieh; Lai, Chin-Rong

    2015-01-01

    In this paper, we present a reliable and robust biometric verification method based on bimodal physiological characteristics of palms, including the palmprint and palm-dorsum vein patterns. The proposed method consists of five steps: (1) automatically aligning and cropping the same region of interest from different palm or palm-dorsum images; (2) applying the digital wavelet transform and inverse wavelet transform to fuse palmprint and vein pattern images; (3) extracting the line-like features (LLFs) from the fused image; (4) obtaining multiresolution representations of the LLFs by using a multiresolution filter; and (5) using a support vector machine to verify the multiresolution representations of the LLFs. The proposed method possesses four advantages: first, both modal images are captured in peg-free scenarios to improve the user-friendliness of the verification device. Second, palmprint and vein pattern images are captured using a low-resolution digital scanner and infrared (IR) camera. The use of low-resolution images results in a smaller database. In addition, the vein pattern images are captured through the invisible IR spectrum, which improves antispoofing. Third, since the physiological characteristics of palmprint and vein pattern images are different, a hybrid fusing rule can be introduced to fuse the decomposition coefficients of different bands. The proposed method fuses decomposition coefficients at different decomposed levels, with different image sizes, captured from different sensor devices. Finally, the proposed method operates automatically and hence no parameters need to be set manually. Three thousand palmprint images and 3000 vein pattern images were collected from 100 volunteers to verify the validity of the proposed method. The results show a false rejection rate of 1.20% and a false acceptance rate of 1.56%. It demonstrates the validity and excellent performance of our proposed method comparing to other methods. PMID:26703596

  16. Bimodal Biometric Verification Using the Fusion of Palmprint and Infrared Palm-Dorsum Vein Images.

    PubMed

    Lin, Chih-Lung; Wang, Shih-Hung; Cheng, Hsu-Yung; Fan, Kuo-Chin; Hsu, Wei-Lieh; Lai, Chin-Rong

    2015-12-12

    In this paper, we present a reliable and robust biometric verification method based on bimodal physiological characteristics of palms, including the palmprint and palm-dorsum vein patterns. The proposed method consists of five steps: (1) automatically aligning and cropping the same region of interest from different palm or palm-dorsum images; (2) applying the digital wavelet transform and inverse wavelet transform to fuse palmprint and vein pattern images; (3) extracting the line-like features (LLFs) from the fused image; (4) obtaining multiresolution representations of the LLFs by using a multiresolution filter; and (5) using a support vector machine to verify the multiresolution representations of the LLFs. The proposed method possesses four advantages: first, both modal images are captured in peg-free scenarios to improve the user-friendliness of the verification device. Second, palmprint and vein pattern images are captured using a low-resolution digital scanner and infrared (IR) camera. The use of low-resolution images results in a smaller database. In addition, the vein pattern images are captured through the invisible IR spectrum, which improves antispoofing. Third, since the physiological characteristics of palmprint and vein pattern images are different, a hybrid fusing rule can be introduced to fuse the decomposition coefficients of different bands. The proposed method fuses decomposition coefficients at different decomposed levels, with different image sizes, captured from different sensor devices. Finally, the proposed method operates automatically and hence no parameters need to be set manually. Three thousand palmprint images and 3000 vein pattern images were collected from 100 volunteers to verify the validity of the proposed method. The results show a false rejection rate of 1.20% and a false acceptance rate of 1.56%. It demonstrates the validity and excellent performance of our proposed method comparing to other methods.

  17. Hybrid zones and the speciation continuum in Heliconius butterflies.

    PubMed

    Mallet, James; Dasmahapatra, Kanchon K

    2012-12-01

    Tropical butterflies in the genus Heliconius have long been models in the study of the stages of speciation. Heliconius are unpalatable to predators, and many species are notable for multiple geographic populations with striking warning colour pattern differences associated with Müllerian mimicry. A speciation continuum is evident in Heliconius hybrid zones. Examples range from hybrid zones across which (a) there is little genetic differentiation other than at mimicry loci, but where hybrids are common, (b) to 'bimodal' hybrid zones with strong genetic divergence and few hybrids, (c) through to 'good' sympatric species, with hybridization extremely rare or absent. Now, in this issue of Molecular Ecology, Arias et al. (2012) have found an intermediate case in Colombian Heliconius cydno showing evidence for assortative mating and molecular differences, but where hybrids are abundant.

  18. Tensile Deformation and Fracture Mechanism of Bulk Bimodal Ultrafine-Grained Al-Mg Alloy

    NASA Astrophysics Data System (ADS)

    Lee, Zonghoon; Radmilovic, Velimir; Ahn, Byungmin; Lavernia, Enrique J.; Nutt, Steven R.

    2010-04-01

    The tensile fractures of ultrafine-grained (UFG) Al-Mg alloy with a bimodal grain size were investigated at the micro- and macroscale using transmission electron microscopy (TEM), scanning electron microscopy (SEM) equipped with focused ion beam (FIB), and optical microscopy. The nanoscale voids and crack behaviors near the tensile fracture surfaces were revealed in various scale ranges and provided the evidence to determine the underlying tensile deformation and fracture mechanisms associated with the bulk bimodal metals. The bimodal grain structures exhibit unusual deformation and fracture mechanisms similar to ductile-phase toughening of brittle materials. The ductile coarse grains in the UFG matrix effectively impede propagation of microcracks, resulting in enhanced ductility and toughness while retaining high strength. In view of the observations collected, we propose a descriptive model for tensile deformation and fracture of bimodal UFG metals.

  19. Physically based closed-form expression for the bimodal unsaturated hydraulic conductivity function.

    PubMed

    Liu, Shiyu; Yasufuku, Noriyuki; Liu, Qiang; Hemanta, Hazarika

    2013-01-01

    Simulation of flow and contaminant transport through the vadose zone requires accurate parameterization of the soil hydraulic properties. This requirement is particularly important for soils with a complex structure. In the present study, a physically based closed-form expression for the bimodal unsaturated hydraulic conductivity function is proposed for soils with bimodal pore-size distribution. It combines the bimodal representation of the soil-water characteristic curve (SWCC) function of Liu with the conductivity representation model of Mualem. The proposed equations are defined by parameters that have physical significance, which can be related to the properties of the materials. Experimental data for the representation of bimodal SWCCs and corresponding hydraulic conductivity curves were used to demonstrate the applicability of the proposed functions. The proposed approaches resulted in good agreement with experimental data. These functions can potentially be used as an effective tool for identifying hydraulic porosities in mediums with a complex structure.

  20. Development and validation of a biologically realistic tissue-mimicking material for photoacoustics and other bimodal optical-acoustic modalities

    NASA Astrophysics Data System (ADS)

    Vogt, William C.; Jia, Congxian; Wear, Keith A.; Garra, Brian S.; Pfefer, T. Joshua

    2017-03-01

    Recent years have seen rapid development of hybrid optical-acoustic imaging modalities with broad applications in research and clinical imaging, including photoacoustic tomography (PAT), photoacoustic microscopy, and ultrasound-modulated optical tomography. Tissue-mimicking phantoms are an important tool for objectively and quantitatively simulating in vivo imaging system performance. However, no standard tissue phantoms exist for such systems. One major challenge is the development of tissue-mimicking materials (TMMs) that are both highly stable and possess biologically realistic properties. To address this need, we have explored the use of various formulations of PVC plastisol (PVCP) based on varying mixtures of several liquid plasticizers. We developed a custom PVCP formulation with optical absorption and scattering coefficients, speed of sound, and acoustic attenuation that are tunable and tissue-relevant. This TMM can simulate different tissue compositions and offers greater mechanical strength than hydrogels. Optical properties of PVCP samples with varying composition were characterized using integrating sphere spectrophotometry and the inverse adding-doubling method. Acoustic properties were determined using a broadband pulse-transmission technique. To demonstrate the utility of this bimodal TMM, we constructed an image quality phantom designed to enable quantitative evaluation of PAT spatial resolution. The phantom was imaged using a custom combined PAT-ultrasound imaging system. Results indicated that this more biologically realistic TMM produced performance trends not captured in simpler liquid phantoms. In the future, this TMM may be broadly utilized for performance evaluation of optical, acoustic, and hybrid optical-acoustic imaging systems.

  1. [Benefit of Bimodal Stimulation with Cochlear Implant and Hearing Aid in Elderly Patients].

    PubMed

    Hinder, Dominik; Linder, Thomas E; Schlegel-Wagner, Christoph; Candreia, Claudia

    2017-07-01

    Cochlear implant (CI) surgery is the standard of care for postlingual deafness in adults. A hearing aid (HA) for the non-implanted ear is normally used if residual hearing is available. There is limited data on bimodal stimulation in elderly patients. We compare the outcome of bimodal stimulation and analyzed the correlation of bimodal benefit and residual hearing in elderly patients. 22 patients≥70 years were implanted with a single-sided CI from 2002 till 2014. 17 patients use a HA on the non-implanted ear (bimodal). In a retrospective chart review we analyzed the audiological benefit (pure tone average, speech recognition). Time to follow-up was 6 month to 12 years. The subjective benefit was assessed using a structured questionnaire. The speech recognition (monosyllabic word testing in quiet @ 65 dB SPL) showed a score of 61% in bimodal condition vs. 53% with CI alone (p=0.35). There was no statistically significant correlation between residual hearing in the lower frequencies (250 Hz, 500 Hz and 1 kHz) and bimodal benefit. Most elderly patients benefit from bimodal stimulation. In quiet and in comparison with CI alone, most patients showed some improvement in word recognition scores using bimodal fitting, and all of them were using the contralateral hearing aid all day long. Postlingual deafened elderly patients fitted with a unilateral CI require a short rehabilitation period. In case of contralateral hearing aid fitting, regular control of the hearing aid should not be overlooked. © Georg Thieme Verlag KG Stuttgart · New York.

  2. Integration of visual and infrared information in bimodal neurons in the rattlesnake optic tectum

    SciTech Connect

    Newman, E.A.; Hartline, P.H.

    1981-08-14

    Bimodal neurons in the rattlesnake tectum, which receive sensory input from the retina and from the infrared-sensing pit organ, exhibit novel, highly nonlinear cross-modality interactions. Some units respond only to simultaneous bimodal stimulation. Others respond to only one of the two modalities, but show greatly enhanced or depressed responses when stimulated simultaneously in the second modality. These cross-modality interactions may play an important role in recognizing and orienting toward biologically important objects.

  3. THE SLUGGS SURVEY: NGC 3115, A CRITICAL TEST CASE FOR METALLICITY BIMODALITY IN GLOBULAR CLUSTER SYSTEMS

    SciTech Connect

    Brodie, Jean P.; Conroy, Charlie; Arnold, Jacob A.; Romanowsky, Aaron J.; Usher, Christopher; Forbes, Duncan A.; Strader, Jay

    2012-11-10

    Due to its proximity (9 Mpc) and the strongly bimodal color distribution of its spectroscopically well-sampled globular cluster (GC) system, the early-type galaxy NGC 3115 provides one of the best available tests of whether the color bimodality widely observed in GC systems generally reflects a true metallicity bimodality. Color bimodality has alternatively been attributed to a strongly nonlinear color-metallicity relation reflecting the influence of hot horizontal-branch stars. Here, we couple Subaru Suprime-Cam gi photometry with Keck/DEIMOS spectroscopy to accurately measure GC colors and a CaT index that measures the Ca II triplet. We find the NGC 3115 GC system to be unambiguously bimodal in both color and the CaT index. Using simple stellar population models, we show that the CaT index is essentially unaffected by variations in horizontal-branch morphology over the range of metallicities relevant to GC systems (and is thus a robust indicator of metallicity) and confirm bimodality in the metallicity distribution. We assess the existing evidence for and against multiple metallicity subpopulations in early- and late-type galaxies and conclude that metallicity bi/multimodality is common. We briefly discuss how this fundamental characteristic links directly to the star formation and assembly histories of galaxies.

  4. Robustness analysis of bimodal networks in the whole range of degree correlation.

    PubMed

    Mizutaka, Shogo; Tanizawa, Toshihiro

    2016-08-01

    We present an exact analysis of the physical properties of bimodal networks specified by the two peak degree distribution fully incorporating the degree-degree correlation between node connections. The structure of the correlated bimodal network is uniquely determined by the Pearson coefficient of the degree correlation, keeping its degree distribution fixed. The percolation threshold and the giant component fraction of the correlated bimodal network are analytically calculated in the whole range of the Pearson coefficient from -1 to 1 against two major types of node removal, which are the random failure and the degree-based targeted attack. The Pearson coefficient for next-nearest-neighbor pairs is also calculated, which always takes a positive value even when the correlation between nearest-neighbor pairs is negative. From the results, it is confirmed that the percolation threshold is a monotonically decreasing function of the Pearson coefficient for the degrees of nearest-neighbor pairs increasing from -1 and 1 regardless of the types of node removal. In contrast, the node fraction of the giant component for bimodal networks with positive degree correlation rapidly decreases in the early stage of random failure, while that for bimodal networks with negative degree correlation remains relatively large until the removed node fraction reaches the threshold. In this sense, bimodal networks with negative degree correlation are more robust against random failure than those with positive degree correlation.

  5. Robustness analysis of bimodal networks in the whole range of degree correlation

    NASA Astrophysics Data System (ADS)

    Mizutaka, Shogo; Tanizawa, Toshihiro

    2016-08-01

    We present an exact analysis of the physical properties of bimodal networks specified by the two peak degree distribution fully incorporating the degree-degree correlation between node connections. The structure of the correlated bimodal network is uniquely determined by the Pearson coefficient of the degree correlation, keeping its degree distribution fixed. The percolation threshold and the giant component fraction of the correlated bimodal network are analytically calculated in the whole range of the Pearson coefficient from -1 to 1 against two major types of node removal, which are the random failure and the degree-based targeted attack. The Pearson coefficient for next-nearest-neighbor pairs is also calculated, which always takes a positive value even when the correlation between nearest-neighbor pairs is negative. From the results, it is confirmed that the percolation threshold is a monotonically decreasing function of the Pearson coefficient for the degrees of nearest-neighbor pairs increasing from -1 and 1 regardless of the types of node removal. In contrast, the node fraction of the giant component for bimodal networks with positive degree correlation rapidly decreases in the early stage of random failure, while that for bimodal networks with negative degree correlation remains relatively large until the removed node fraction reaches the threshold. In this sense, bimodal networks with negative degree correlation are more robust against random failure than those with positive degree correlation.

  6. An effective inversion algorithm for retrieving bimodal aerosol particle size distribution from spectral extinction data

    NASA Astrophysics Data System (ADS)

    He, Zhenzong; Qi, Hong; Yao, Yuchen; Ruan, Liming

    2014-12-01

    The Ant Colony Optimization algorithm based on the probability density function (PDF-ACO) is applied to estimate the bimodal aerosol particle size distribution (PSD). The direct problem is solved by the modified Anomalous Diffraction Approximation (ADA, as an approximation for optically large and soft spheres, i.e., χ≫1 and |m-1|≪1) and the Beer-Lambert law. First, a popular bimodal aerosol PSD and three other bimodal PSDs are retrieved in the dependent model by the multi-wavelength extinction technique. All the results reveal that the PDF-ACO algorithm can be used as an effective technique to investigate the bimodal PSD. Then, the Johnson's SB (J-SB) function and the modified beta (M-β) function are employed as the general distribution function to retrieve the bimodal PSDs under the independent model. Finally, the J-SB and M-β functions are applied to recover actual measurement aerosol PSDs over Beijing and Shanghai obtained from the aerosol robotic network (AERONET). The numerical simulation and experimental results demonstrate that these two general functions, especially the J-SB function, can be used as a versatile distribution function to retrieve the bimodal aerosol PSD when no priori information about the PSD is available.

  7. Synergistic dual positive feedback loops established by molecular sequestration generate robust bimodal response.

    PubMed

    Venturelli, Ophelia S; El-Samad, Hana; Murray, Richard M

    2012-11-27

    Feedback loops are ubiquitous features of biological networks and can produce significant phenotypic heterogeneity, including a bimodal distribution of gene expression across an isogenic cell population. In this work, a combination of experiments and computational modeling was used to explore the roles of multiple feedback loops in the bimodal, switch-like response of the Saccharomyces cerevisiae galactose regulatory network. Here, we show that bistability underlies the observed bimodality, as opposed to stochastic effects, and that two unique positive feedback loops established by Gal1p and Gal3p, which both regulate network activity by molecular sequestration of Gal80p, induce this bimodality. Indeed, systematically scanning through different single and multiple feedback loop knockouts, we demonstrate that there is always a concentration regime that preserves the system's bimodality, except for the double deletion of GAL1 and the GAL3 feedback loop, which exhibits a graded response for all conditions tested. The constitutive production rates of Gal1p and Gal3p operate as bifurcation parameters because variations in these rates can also abolish the system's bimodal response. Our model indicates that this second loss of bistability ensues from the inactivation of the remaining feedback loop by the overexpressed regulatory component. More broadly, we show that the sequestration binding affinity is a critical parameter that can tune the range of conditions for bistability in a circuit with positive feedback established by molecular sequestration. In this system, two positive feedback loops can significantly enhance the region of bistability and the dynamic response time.

  8. The relative phonetic contributions of a cochlear implant and residual acoustic hearing to bimodal speech perception.

    PubMed

    Sheffield, Benjamin M; Zeng, Fan-Gang

    2012-01-01

    The addition of low-passed (LP) speech or even a tone following the fundamental frequency (F0) of speech has been shown to benefit speech recognition for cochlear implant (CI) users with residual acoustic hearing. The mechanisms underlying this benefit are still unclear. In this study, eight bimodal subjects (CI users with acoustic hearing in the non-implanted ear) and eight simulated bimodal subjects (using vocoded and LP speech) were tested on vowel and consonant recognition to determine the relative contributions of acoustic and phonetic cues, including F0, to the bimodal benefit. Several listening conditions were tested (CI/Vocoder, LP, T(F0-env), CI/Vocoder + LP, CI/Vocoder + T(F0-env)). Compared with CI/Vocoder performance, LP significantly enhanced both consonant and vowel perception, whereas a tone following the F0 contour of target speech and modulated with an amplitude envelope of the maximum frequency of the F0 contour (T(F0-env)) enhanced only consonant perception. Information transfer analysis revealed a dual mechanism in the bimodal benefit: The tone representing F0 provided voicing and manner information, whereas LP provided additional manner, place, and vowel formant information. The data in actual bimodal subjects also showed that the degree of the bimodal benefit depended on the cutoff and slope of residual acoustic hearing. © 2012 Acoustical Society of America.

  9. In Vivo Imaging of GLP-1R with a Targeted Bimodal PET/Fluorescence Imaging Agent

    PubMed Central

    2015-01-01

    Accurate visualization and quantification of β-cell mass is critical for the improved understanding, diagnosis, and treatment of both type 1 diabetes (T1D) and insulinoma. Here, we describe the synthesis of a bimodal imaging probe (PET/fluorescence) for imaging GLP-1R expression in the pancreas and in pancreatic islet cell tumors. The conjugation of a bimodal imaging tag containing a near-infrared fluorescent dye, and the copper chelator sarcophagine to the GLP-1R targeting peptide exendin-4 provided the basis for the bimodal imaging probe. Conjugation was performed via a novel sequential one-pot synthetic procedure including 64Cu radiolabeling and copper-catalyzed click-conjugation. The bimodal imaging agent 64Cu-E4-Fl was synthesized in good radiochemical yield and specific activity (RCY = 36%, specific activity: 141 μCi/μg, >98% radiochemical purity). The agent showed good performance in vivo and ex vivo, visualizing small xenografts (<2 mm) with PET and pancreatic β-cell mass by phosphor autoradiography. Using the fluorescent properties of the probe, we were able to detect individual pancreatic islets, confirming specific binding to GLP-1R and surpassing the sensitivity of the radioactive label. The use of bimodal PET/fluorescent imaging probes is promising for preoperative imaging and fluorescence-assisted analysis of patient tissues. We believe that our procedure could become relevant as a protocol for the development of bimodal imaging agents. PMID:24856928

  10. The predominant bacteria isolated from radicular cysts

    PubMed Central

    2013-01-01

    Purpose To detect predominant bacteria associated with radicular cysts and discuss in light of the literature. Material and methods Clinical materials were obtained from 35 radicular cysts by aspiration. Cultures were made from clinical materials by modern laboratory techniques, they underwent microbiologic analysis. Results The following are microorganisms isolated from cultures: Streptococcus milleri Group (SMG) (23.8%) [Streptococcus constellatus (19.1%) and Streptococcus anginosus (4.7%)], Streptococcus sanguis (14.3%), Streptococcus mitis (4.7%), Streptococcus cremoris (4.7%), Peptostreptococcus pevotii (4.7%), Prevotella buccae (4.7%), Prevotella intermedia (4.7%), Actinomyces meyeri (4.7%), Actinomyces viscosus (4.7%), Propionibacterium propionicum (4.7%), Bacteroides capillosus (4.7%), Staphylococcus hominis (4.7%), Rothia denticariosa (4.7%), Gemella haemolysans (4.7%), and Fusobacterium nucleatum (4.7%). Conclusions Results of this study demonstrated that radicular cysts show a great variety of anaerobic and facultative anaerobic bacterial flora. It was observed that all isolated microorganisms were the types commonly found in oral flora. Although no specific microorganism was found, Streptococcus spp. bacteria (47.5%) – especially SMG (23.8%) – were predominantly found in the microorganisms isolated. Furthermore, radicular cysts might be polymicrobial originated. Although radicular cyst is an inflammatory cyst, some radicular cyst fluids might be sterile. PMID:24011184

  11. Bimodal Imaging at ICON Using Neutrons and X-rays

    NASA Astrophysics Data System (ADS)

    Kaestner, A. P.; Hovind, J.; Boillat, P.; Muehlebach, C.; Carminati, C.; Zarebanadkouki, M.; Lehmann, E. H.

    For experiments with low contrast between the relevant features it can be beneficial to add a second modality to reduce ambiguity. At Paul Scherrer Institut the two neutron imaging facilities NEUTRA (thermal neutrons) and ICON (cold neutrons) we have installed X-ray beamlines for on-site bimodal imaging with neutrons and X-rays. This allows us to leave the sample untouched in the sample environment throughout an experiment and to reduce the waiting times between acquisitions using each modality. The applications and energy ranges of the X-ray installations are different at the two facilities. At NEUTRA larger samples are intended (60-320 kV) and at ICON small samples and simultaneous acquisition are intended (40-150 kV). Here, we report the more recent installation at ICON. The X-ray beamline uses a cone beam source and is arranged across the neutron beamline. The beamline is designed to allow up to ten times magnification. This matches the voxel-size that can be achieved with the micro-setup for neutrons. The oblique arrangement of the X-ray beamline further makes real-time acquisition possible since both modalities have a free view of the sample at any time. Reconstruction of cone beam data requires more knowledge about the beam geometry and sample position. Therefore, the beamline is equipped with laser based distance sensors and a calibration procedure has been developed to increase the accuracy of the reconstruction. The purpose of using multimodal acquisition is to fuse the data in a way that enhances the output of the experiment. We demonstrate the current system performance and provide a basic analysis with experiment data.

  12. The Angstrom Exponent and Bimodal Aerosol Size Distributions

    NASA Technical Reports Server (NTRS)

    Schuster, Gregory L.; Dubovik, Oleg; Holben, Brent H.

    2005-01-01

    Powerlaws have long been used to describe the spectral dependence of aerosol extinction, and the wavelength exponent of the aerosol extinction powerlaw is commonly referred to as the Angstrom exponent. The Angstrom exponent is often used as a qualitative indicator of aerosol particle size, with values greater than two indicating small particles associated with combustion byproducts, and values less than one indicating large particles like sea salt and dust. In this study, we investigate the relationship between the Angstrom exponent and the mode parameters of bimodal aerosol size distributions using Mie theory calculations and Aerosol Robotic Network (AERONET) retrievals. We find that Angstrom exponents based upon seven wavelengths (0.34, 0.38, 0.44, 0.5, 0.67, 0.87, and 1.02 micrometers) are sensitive to the volume fraction of aerosols with radii less then 0.6 micrometers, but not to the fine mode effective radius. The Angstrom exponent is also known to vary with wavelength, which is commonly referred to as curvature; we show how the spectral curvature can provide additional information about aerosol size distributions for intermediate values of the Angstrom exponent. Curvature also has a significant effect on the conclusions that can be drawn about two-wavelength Angstrom exponents; long wavelengths (0.67, 0.87 micrometers) are sensitive to fine mode volume fraction of aerosols but not fine mode effective radius, while short wavelengths (0.38, 0.44 micrometers) are sensitive to the fine mode effective radius but not the fine mode volume fraction.

  13. Bimodal tholeiitic-dacitic magmatism and the Early Precambrian crust

    USGS Publications Warehouse

    Barker, F.; Peterman, Z.E.

    1974-01-01

    Interlayered plagioclase-quartz gneisses and amphibolites from 2.7 to more than 3.6 b.y. old form much of the basement underlying Precambrian greenstone belts of the world; they are especially well-developed and preserved in the Transvaal and Rhodesian cratons. We postulate that these basement rocks are largely a metamorphosed, volcanic, bimodal suite of tholeiite and high-silica low-potash dacite-compositionally similar to the 1.8-b.y.-old Twilight Gneiss - and partly intrusive equivalents injected into the lower parts of such volcanic piles. We speculate that magmatism in the Early Precambrian involved higher heat flow and more hydrous conditions than in the Phanerozoic. Specifically, we suggest that the early degassing of the Earth produced a basaltic crust and pyrolitic upper mantle that contained much amphibole, serpentine, and other hydrous minerals. Dehydration of the lower parts of a downgoing slab of such hydrous crust and upper mantle would release sufficient water to prohibit formation of andesitic liquid in the upper part of the slab. Instead, a dacitic liquid and a residuum of amphibole and other silica-poor phases would form, according to Green and Ringwood's experimental results. Higher temperatures farther down the slab would cause total melting of basalt and generation of the tholeiitic member of the suite. This type of magma generation and volcanism persisted until the early hydrous lithosphere was consumed. An implication of this hypothesis is that about half the present volume of the oceans formed before about 2.6 b.y. ago. ?? 1974.

  14. Bimodality of Circumstellar Disk Evolution Induced by the Hall Current

    NASA Astrophysics Data System (ADS)

    Tsukamoto, Y.; Iwasaki, K.; Okuzumi, S.; Machida, M. N.; Inutsuka, S.

    2015-09-01

    The formation process of circumstellar disks is still controversial because of the interplay of complex physical processes that occurs during the gravitational collapse of prestellar cores. In this study, we investigate the effect of the Hall current term on the formation of the circumstellar disk using three-dimensional simulations. In our simulations, all non-ideal effects, as well as the radiation transfer, are considered. The size of the disk is significantly affected by a simple difference in the inherent properties of the prestellar core, namely whether the rotation vector and the magnetic field are parallel or anti-parallel. In the former case, only a very small disk (\\lt 1 {AU}) is formed. On the other hand, in the latter case, a massive and large (\\gt 20 {AU}) disk is formed in the early phase of protostar formation. Since the parallel and anti-parallel properties do not readily change, we expect that the parallel and anti-parallel properties are also important in the subsequent disk evolution and the difference between the two cases is maintained or enhanced. This result suggests that the disk size distribution of the Class 0 young stellar objects is bimodal. Thus, the disk evolution can be categorized into two cases and we may call the parallel and anti-parallel systems Ortho-disk and Para-disk, respectively. We also show that the anti-rotating envelopes against the disk rotation appear with a size of ≳ 200 {AU}. We predict that the anti-rotating envelope will be found in the future observations.

  15. Rituximab in lymphocyte-predominant Hodgkin disease.

    PubMed

    Azim, Hatem A; Pruneri, Giancarlo; Cocorocchio, Emilia; Cinieri, Saverio; Raviele, Paola R; Bassi, Simona; Preda, Lorenzo; Martinelli, Giovanni; Peccatori, Fedro A

    2009-01-01

    Lymphocyte-predominant Hodgkin disease (LPHD) differs in biology and clinical behaviour from classic Hodgkin disease. Almost 100% of LPHD neoplastic cells express CD20 and thus rituximab could be effective; yet limited data are available. We performed a retrospective analysis on patients with LPHD who were treated with rituximab at our institution to determine the magnitude of benefit offered by this drug. Seven patients were identified; 4 received the drug as single agent while the rest received it in combination with chemotherapy. All except 2 received the drug in the salvage setting. Response rate was 100% with 6 of 7 patients achieving complete remission. At a median follow-up of 2 years, 4 patients are still disease free while the rest relapsed at a median time of 27 months. Rituximab is effective in LPHD and should be considered; however, the optimal schedule remains to be determined.

  16. [Left predominance of varices: myth or reality?].

    PubMed

    Cornu-Thénard, A; Maraval, M; Boivin, P; Parpex, P

    1986-01-01

    The study of 843 legs operated for major varices shows that they are equally distributed between the two lower limbs (48.6% on the right, 51.4% on the left). There is little sex-determined variation in this distribution (410 women - 184 men), the main difference being that found in men: +4.6% on the left. Other studies carried out in Europe come to much the same conclusion. Two of these studies do, however, note a much clearer predominance of left-leg varices in men (+10%). For some studies, the lack of information about the type of varices being considered has proved troublesome (for example the many isolated telangiectasis and varices) and means that it is impossible to come to any exact conclusion. Clinical quantification is therefore desirable: at least it takes into account the diameter of the varices studied.

  17. Bimodal Silurian and Lower Devonian volcanic rock assemblages in the Machias-Eastport area, Maine

    USGS Publications Warehouse

    Gates, Olcott; Moench, R.H.

    1981-01-01

    Exposed in the Machias-Eastport area of southeastern Maine is the thickest (at least 8,000 m), best exposed, best dated, and most nearly complete succession of Silurian and Lower Devonian volcanic strata in the coastal volcanic belt, remnants of which crop out along the coasts of southern New Brunswick, Canada, and southeastern New England in the United States. The volcanics were erupted through the 600-700-million-year-old Avalonian sialic basement. To test the possibility that this volcanic belt was a magmatic arc above a subduction zone prior to presumed Acadian continental collision, samples representing the entire section in the Machias-Eastport area of Maine were chemically analyzed. Three strongly bimodal assemblages of volcanic rocks and associated intrusives are recognized, herein called the Silurian, older Devonian, and younger Devonian assemblages. The Silurian assemblage contains typically nonporphyritic high-alumina tholeiitic basalts, basaltic andesites, and diabase of continental characterand calc-alkalic rhyolites, silicic dacites, and one known dike of andesite. These rocks are associated with fossiliferous, predominantly marine strata of the Quoddy, Dennys, and Edmunds Formations, and the Leighton Formation of the Pembroke Group (the stratigraphic rank of both is revised herein for the Machias-Eastport area), all of Silurian age. The shallow marine Hersey Formation (stratigraphic rank also revised herein) of the Pembroke Group, of latest Silurian age (and possibly earliest Devonian, as suggested by an ostracode fauna), contains no known volcanics; and it evidently was deposited during a volcanic hiatus that immediately preceded emergence of the coastal volcanic belt and the eruption of the older Devonian assemblage. The older Devonian assemblage, in the lagoonal to subaerial Lower Devonian Eastport Formation, contains tholeiitic basalts and basaltic andesites, typically with abundant plagioclase phenocrysts and typically richer in iron and

  18. Possibility of star (pyramid) dune development in the area of bimodal wind regime

    NASA Astrophysics Data System (ADS)

    Biejat, K.

    2012-04-01

    Star (pyramid) dunes are the largest aeolian landforms. They can occur in three types - simple, complex and compound. Development of this type of dunes is usually connected with multidirectional or complex wind regimes. The aim of this study was to verify a hypothesis that the star dunes can also develop by a bimodal wind regime and by local modifications of nearsurface wind flow directions. Field study was performed on Erg Chebbi, in southern Morocco. Several star and transverse dunes were selected for the study of their shape. The star dunes were analysed concerning their type and position in the dune field. This erg contains all of three types of star dunes together with transverse dunes. The regional wind data show that there are two dominant wind directions - NE (Chergui) and SW (Saheli). To determine the difference in shape of star dunes, we performed topographic surveying by GPS RTK. The results allowed to create 3D models of star dunes. The models were used to determine metric characteristics of star dunes, including area of dune basis, volume, and slope angles. On the basis of 3D models, primary, secondary and, on the compound dunes, tertiary arms were determined. Primary arms on each type of star dunes, as well as crestlines of transverse dunes, have dominant orientation NW-SE, perpendicular to two dominant wind directions. This clearly confirms that star dunes of Erg Chebbi develop by a bimodal wind regime In contrast to primary arms, subsidiary (secondary and tertiary) arms are not connected to general wind regime. The secondary arms of star dunes occur to be differentially developer. There are more subsidiary arms on SW sides in comparison to the E sides of the dunes where inclination of slopes is constant. It can be therefore inferred that sand has been supplied predominantly from SW direction. This is supported by distribution of the dunes on the erg. Most compound star dunes compose a chain along the E margin of the erg. Comparison of compound star

  19. Bimodal Seismic Anisotropy at Cotopaxi volcano (Ecuador): Possible implications

    NASA Astrophysics Data System (ADS)

    Amin Douillet, Guilhem; Ruiz, Mario; Robin, Claude

    2010-05-01

    A shear wave splitting analysis was performed on Cotopaxi volcano, one of Ecuador most active and hazardous volcanoes, in order to investigate the stress state under this volcano. Cotopaxi volcano is located in a highly populated area including the capital Quito. It's eruptive cycle is approximately 120 ±70 years and apart from possible minor eruptions in 1942 and 1903-1904, the last volcanic activity dates from 1878-1885. Moreover, 15 years of increasing seismicity with some major crisis during the 1995-2010 periods, lead to the current very high seismic level. Finally two years of gas monitoring suggest that the Cotopaxi's emissions are currently intermittent and passive, but non negligible. We analyzed 102 regional tectonic events recorded between 2006 and 2009 at a network of five broad-band three-component seismic stations. These stations are located on all flanks of Cotopaxi. The events used were from several seismic sources located inside a radius of 200 kilometers from the volcano and illuminate all space directions. Seismic events were manually chosen based on their clear shear wave component in regards to the compression wave and to the noise. The data were computed using Matlab software. Polarization directions and delay times of split shear waves were found using a method based on the cross correlation of displacement waveforms of shear-waves at all possible rotation angles. Our results show a bimodal anisotropic behavior. One of the fast-directions axes follows the regional Ecuadorian tectonic general strain with a ESE direction. The other trend was found to be perpendicular to the regional strain. Other studies have shown that a 90° flip may take place either prior, during, or just after the main eruptive phase, or during hydraulic injections. This 90° flip is probably relied to micro cracks filling and pressuring, creating a local reverse strain field. There is not clear trend on temporal evolution of anisotropy distribution on our data. Only one

  20. Lateral Erosion Encourages Vertical Incision in a Bimodal Alluvial River

    NASA Astrophysics Data System (ADS)

    Gran, K. B.

    2015-12-01

    Sand can have a strong impact on gravel transport, increasing gravel transport rates by orders of magnitude as sand content increases. Recent experimental work by others indicates that adding sand to an armored bed can even cause armor to break-up and mobilize. These two elements together help explain observations from a bimodal sand and gravel-bedded river, where lateral migration into sand-rich alluvium breaks up the armor layer, encouraging further incision into the bed. Detailed bedload measurements were coupled with surface and subsurface grain size analyses and cross-sectional surveys in a seasonally-incised channel carved into the upper alluvial fan of the Pasig-Potrero River at Mount Pinatubo, Philippines. Pinatubo erupted in 1991, filling valleys draining the flanks of the volcano with primarily sand-sized pyroclastic flow debris. Twenty years after the eruption, sand-rich sediment inputs are strongly seasonal, with most sediment input to the channel during the rainy season. During the dry season, flow condenses from a wide braided planform to a single-thread channel in most of the upper basin, extending several km onto the alluvial fan. This change in planform creates similar unit discharge ranges in summer and winter. Lower sediment loads in the dry season drive vertical incision until the bed is sufficiently armored. Incision proceeds downstream in a wave, with increasing sediment transport rates and decreasing grain size with distance downstream, eventually reaching a gravel-sand transition and return to a braided planform. Incision depths in the gravel-bedded section exceeded 3 meters in parts of a 4 km-long study reach, a depth too great to be explained by predictions from simple winnowing during incision. Instead, lateral migration into sand-rich alluvium provides sufficient fine sediment to break up the armor surface, allowing incision to start anew and increasing the total depth of the seasonally-incised valley. Lateral migration is recorded in a

  1. Integrated propulsion and power modeling for bimodal nuclear thermal rockets

    NASA Astrophysics Data System (ADS)

    Clough, Joshua

    Bimodal nuclear thermal rocket (BNTR) engines have been shown to reduce the weight of space vehicles to the Moon, Mars, and beyond by utilizing a common reactor for propulsion and power generation. These savings lead to reduced launch vehicle costs and/or increased mission safety and capability. Experimental work of the Rover/NERVA program demonstrated the feasibility of NTR systems for trajectories to Mars. Numerous recent studies have demonstrated the economic and performance benefits of BNTR operation. Relatively little, however, is known about the reactor-level operation of a BNTR engine. The objective of this dissertation is to develop a numerical BNTR engine model in order to study the feasibility and component-level impact of utilizing a NERVA-derived reactor as a heat source for both propulsion and power. The primary contribution is to provide the first-of-its-kind model and analysis of a NERVA-derived BNTR engine. Numerical component models have been modified and created for the NERVA reactor fuel elements and tie tubes, including 1-D coolant thermodynamics and radial thermal conduction with heat generation. A BNTR engine system model has been created in order to design and analyze an engine employing an expander-cycle nuclear rocket and Brayton cycle power generator using the same reactor. Design point results show that a 316 MWt reactor produces a thrust and specific impulse of 66.6 kN and 917 s, respectively. The same reactor can be run at 73.8 kWt to produce the necessary 16.7 kW electric power with a Brayton cycle generator. This demonstrates the feasibility of BNTR operation with a NERVA-derived reactor but also indicates that the reactor control system must be able to operate with precision across a wide power range, and that the transient analysis of reactor decay heat merits future investigation. Results also identify a significant reactor pressure-drop limitation during propulsion and power-generation operation that is caused by poor tie tube

  2. Evaluation of Hearing Aid Frequency Response Fittings in Pediatric and Young Adult Bimodal Recipients

    PubMed Central

    Davidson, Lisa S.; Firszt, Jill B.; Brenner, Chris; Cadieux, Jamie H.

    2015-01-01

    Background A coordinated fitting of a cochlear implant (CI) and contralateral hearing aid (HA) for bimodal device use should emphasize balanced audibility and loudness across devices. However, guidelines for allocating frequency information to the CI and HA are not well established for the growing population of bimodal recipients. Purpose The study aim was to compare the effects of three different HA frequency responses, when fitting a CI and an HA for bimodal use, on speech recognition and localization in children/young adults. Specifically, the three frequency responses were wideband, restricted high frequency, and nonlinear frequency compression (NLFC), which were compared with measures of word recognition in quiet, sentence recognition in noise, talker discrimination, and sound localization. Research Design The HA frequency responses were evaluated using an A B1 A B2 test design: wideband frequency response (baseline-A), restricted high-frequency response (experimental-B1), and NLFC-activated (experimental-B2). All participants were allowed 3–4 weeks between each test session for acclimatization to each new HA setting. Bimodal benefit was determined by comparing the bimodal score to the CI-alone score. Study Sample Participants were 14 children and young adults (ages 7–21 yr) who were experienced users of bimodal devices. All had been unilaterally implanted with a Nucleus CI24 internal system and used either a Freedom or CP810 speech processor. All received a Phonak Naida IX UP behind-the-ear HA at the beginning of the study. Data Collection and Analysis Group results for the three bimodal conditions (HA frequency response with wideband, restricted high frequency, and NLFC) on each outcome measure were analyzed using a repeated measures analysis of variance. Group results using the individual “best bimodal” score were analyzed and confirmed using a resampling procedure. Correlation analyses examined the effects of audibility (aided and unaided hearing

  3. Predominance of sperm motion in corners

    NASA Astrophysics Data System (ADS)

    Nosrati, Reza; Graham, Percival J.; Liu, Qiaozhi; Sinton, David

    2016-05-01

    Sperm migration through the female tract is crucial to fertilization, but the role of the complex and confined structure of the fallopian tube in sperm guidance remains unknown. Here, by confocal imaging microchannels head-on, we distinguish corner- vs. wall- vs. bulk-swimming bull sperm in confined geometries. Corner-swimming dominates with local areal concentrations as high as 200-fold that of the bulk. The relative degree of corner-swimming is strongest in small channels, decreases with increasing channel size, and plateaus for channels above 200 μm. Corner-swimming remains predominant across the physiologically-relevant range of viscosity and pH. Together, boundary-following sperm account for over 95% of the sperm distribution in small rectangular channels, which is similar to the percentage of wall swimmers in circular channels of similar size. We also demonstrate that wall-swimming sperm travel closer to walls in smaller channels (~100 μm), where the opposite wall is within the hydrodynamic interaction length-scale. The corner accumulation effect is more than the superposition of the influence of two walls, and over 5-fold stronger than that of a single wall. These findings suggest that folds and corners are dominant in sperm migration in the narrow (sub-mm) lumen of the fallopian tube and microchannel-based sperm selection devices.

  4. Predominance of sperm motion in corners

    PubMed Central

    Nosrati, Reza; Graham, Percival J.; Liu, Qiaozhi; Sinton, David

    2016-01-01

    Sperm migration through the female tract is crucial to fertilization, but the role of the complex and confined structure of the fallopian tube in sperm guidance remains unknown. Here, by confocal imaging microchannels head-on, we distinguish corner- vs. wall- vs. bulk-swimming bull sperm in confined geometries. Corner-swimming dominates with local areal concentrations as high as 200-fold that of the bulk. The relative degree of corner-swimming is strongest in small channels, decreases with increasing channel size, and plateaus for channels above 200 μm. Corner-swimming remains predominant across the physiologically-relevant range of viscosity and pH. Together, boundary-following sperm account for over 95% of the sperm distribution in small rectangular channels, which is similar to the percentage of wall swimmers in circular channels of similar size. We also demonstrate that wall-swimming sperm travel closer to walls in smaller channels (~100 μm), where the opposite wall is within the hydrodynamic interaction length-scale. The corner accumulation effect is more than the superposition of the influence of two walls, and over 5-fold stronger than that of a single wall. These findings suggest that folds and corners are dominant in sperm migration in the narrow (sub-mm) lumen of the fallopian tube and microchannel-based sperm selection devices. PMID:27211846

  5. Effects of Removing Low-Frequency Electric Information on Speech Perception With Bimodal Hearing

    PubMed Central

    Eggleston, Jessica L.; Reavis, Kelly M.; McMillan, Garnett P.; Reiss, Lina A. J.

    2016-01-01

    Purpose The objective was to determine whether speech perception could be improved for bimodal listeners (those using a cochlear implant [CI] in one ear and hearing aid in the contralateral ear) by removing low-frequency information provided by the CI, thereby reducing acoustic–electric overlap. Method Subjects were adult CI subjects with at least 1 year of CI experience. Nine subjects were evaluated in the CI-only condition (control condition), and 26 subjects were evaluated in the bimodal condition. CIs were programmed with 4 experimental programs in which the low cutoff frequency (LCF) was progressively raised. Speech perception was evaluated using Consonant-Nucleus-Consonant words in quiet, AzBio sentences in background babble, and spondee words in background babble. Results The CI-only group showed decreased speech perception in both quiet and noise as the LCF was raised. Bimodal subjects with better hearing in the hearing aid ear (< 60 dB HL at 250 and 500 Hz) performed best for words in quiet as the LCF was raised. In contrast, bimodal subjects with worse hearing (> 60 dB HL at 250 and 500 Hz) performed similarly to the CI-only group. Conclusions These findings suggest that reducing low-frequency overlap of the CI and contralateral hearing aid may improve performance in quiet for some bimodal listeners with better hearing. PMID:26535803

  6. Contributions of Electric and Acoustic Hearing to Bimodal Speech and Music Perception

    PubMed Central

    Crew, Joseph D.; Galvin III, John J.; Landsberger, David M.; Fu, Qian-Jie

    2015-01-01

    Cochlear implant (CI) users have difficulty understanding speech in noisy listening conditions and perceiving music. Aided residual acoustic hearing in the contralateral ear can mitigate these limitations. The present study examined contributions of electric and acoustic hearing to speech understanding in noise and melodic pitch perception. Data was collected with the CI only, the hearing aid (HA) only, and both devices together (CI+HA). Speech reception thresholds (SRTs) were adaptively measured for simple sentences in speech babble. Melodic contour identification (MCI) was measured with and without a masker instrument; the fundamental frequency of the masker was varied to be overlapping or non-overlapping with the target contour. Results showed that the CI contributes primarily to bimodal speech perception and that the HA contributes primarily to bimodal melodic pitch perception. In general, CI+HA performance was slightly improved relative to the better ear alone (CI-only) for SRTs but not for MCI, with some subjects experiencing a decrease in bimodal MCI performance relative to the better ear alone (HA-only). Individual performance was highly variable, and the contribution of either device to bimodal perception was both subject- and task-dependent. The results suggest that individualized mapping of CIs and HAs may further improve bimodal speech and music perception. PMID:25790349

  7. Bimodal Stimulation with Cochlear Implant and Hearing Aid in Cases of Highly Asymmetrical Hearing Loss.

    PubMed

    Sanhueza, Ignacio; Manrique, Raquel; Huarte, Alicia; de Erenchun, Iñigo Ruiz; Manrique, Manuel

    2016-04-01

    Bimodal stimulation is a possible treatment for asymmetrical hearing loss, wherein 1 ear is stimulated with a cochlear implant and the other is stimulated with a hearing aid. This emerging indication has gained significance over the last few years. However, little research has been conducted regarding the performance in different types of asymmetric Hearing loss. This study seeks to prove the bilateral-binaural advantage in a group of patients treated with bimodal stimulation (cochlear implant and hearing aid), with different degrees of hearing loss in their best ear. In total, 31 patients were recruited for the study. They were divided into 3 groups on the basis of the ear with the hearing aid: Group A, pure tone average (PTA) between 41 and 70 dB HL; Group B, PTA between 71 and 80 dB HL; and Group C, PTA between 81 and 90 dB HL. The performance in PTA and disyllabic word recognition were analyzed separately in each ear and then bimodally. The minimum follow-up period was 2 years. There were statistically significant differences between bimodal and monaural conditions both in PTA and in disyllabic word recognition. The better the residual hearing in the ear with the hearing aid, the greater were the benefits obtained with bilateralism-binaurality. Bimodal stimulation provides better results than any monaural hearing mode, regardless of whether it involves the use of a hearing aid alone or a cochlear implant alone.

  8. A Topaz-II bimodal design assessment study and system analysis

    NASA Astrophysics Data System (ADS)

    El-Genk, Mohamed S.; Paramonov, Dmitry V.; Xue, Huimin; Ogloblin, Boris G.; Shumov, Dmitry P.

    1995-01-01

    A preliminary conceptual design study is performed to investigate the feasibility of near-term, simple, minimum design changes to the Russian TOPAZ-II space power system to provide bimodal operation, electric power and direct thermal propulsion for future missions. To simulate the fully integrated, TOPAZ-II Bimodal system the capabilities of the Thermionic Transient Analysis Model (TITAM) are extended to take into account the proposed design modification of the Thermionic Fuel Elements (TFEs), waste heat recovery, pre-injection electric heating of the hydrogen propellant. This system model is used to characterize and identify promising design options and assess the performance parameters of the TOPAZ-II Bimodal system. Results of the study indicate that the TOPAZ-II system can be easily modified to support bimodal missions at a thrust level of 2.5 to 7.5 N and a corresponding specific impulse of 830 s to 600 s, respectively. Testing of TOPAZ-II Bimodal system can be accomplished at the Air Force Thermionic System Evaluation Test (TSET) facility in Albuquerque, New Mexico. The proposed design modification will build on the vast expertise and technology base available at the different Institutes, particularly at the Central Design Bureau of Machine Building (CDBMB) in St. Petersburg.

  9. Early Bimodal Stimulation Benefits Language Acquisition for Children With Cochlear Implants.

    PubMed

    Moberly, Aaron C; Lowenstein, Joanna H; Nittrouer, Susan

    2016-01-01

    Adding a low-frequency acoustic signal to the cochlear implant (CI) signal (i.e., bimodal stimulation) for a period of time early in life improves language acquisition. Children must acquire sensitivity to the phonemic units of language to develop most language-related skills, including expressive vocabulary, working memory, and reading. Acquiring sensitivity to phonemic structure depends largely on having refined spectral (frequency) representations available in the signal, which does not happen with CIs alone. Combining the low-frequency acoustic signal available through hearing aids with the CI signal can enhance signal quality. A period with this bimodal stimulation has been shown to improve language skills in very young children. This study examined whether these benefits persist into childhood. Data were examined for 48 children with CIs implanted under age 3 years, participating in a longitudinal study. All children wore hearing aids before receiving a CI, but upon receiving a first CI, 24 children had at least 1 year of bimodal stimulation (Bimodal group), and 24 children had only electric stimulation subsequent to implantation (CI-only group). Measures of phonemic awareness were obtained at second and fourth grades, along with measures of expressive vocabulary, working memory, and reading. Children in the Bimodal group generally performed better on measures of phonemic awareness, and that advantage was reflected in other language measures. Having even a brief period of time early in life with combined electric-acoustic input provides benefits to language learning into childhood, likely because of the enhancement in spectral representations provided.

  10. Transitioning from Bimodal to Bilateral Cochlear Implant Listening: Speech Recognition and Localization in Four Individuals

    PubMed Central

    Potts, Lisa G.; Litovsky, Ruth Y.

    2014-01-01

    Purpose The use of bilateral stimulation is becoming common for cochlear implant (CI) recipients, with either a CI in one ear and a hearing aid (HA) in the non-implanted ear (CI&HA - bimodal) or CIs in both ears (CI&CI - bilateral). The objective of this study was to evaluate performance of four individuals who transitioned from bimodal to bilateral stimulation. Methods Participants had completed a larger study of bimodal hearing and subsequently received a second CI. Test procedures from the bimodal study, including speech recognition, localization, and a questionnaire (SSQ) were repeated after 6-7 months of experience with bilateral CIs. Speech recognition and localization were measured using words that were presented from unpredictable locations in the room. Results Speech recognition and localization were not different between bimodal and unilateral CI. In contrast, performance was significantly better with CI&CI compared with unilateral CI. Speech recognition with CI&CI was significantly better than with CI&HA for 2/4 participants. Localization was significantly better for all participants with CI&CI compared to CI&HA. CI&CI performance was rated as significantly better on the SSQ compared to CI&HA performance for the four participants. Conclusions There was a strong subjective preference for CI&CI for all participants. The variability in speech recognition and localization, however, suggests that performance under these stimulus conditions is individualized. Differences in hearing and/or HA history may provide an explanation for performance differences. PMID:24018578

  11. Emotional Perception of Music in Children With Bimodal Fitting and Unilateral Cochlear Implant.

    PubMed

    Shirvani, Sareh; Jafari, Zahra; Motasaddi Zarandi, Masoud; Jalaie, Shohre; Mohagheghi, Hamed; Tale, Mohammad Reza

    2016-06-01

    Biological, structural, and acoustical constraints faced by cochlear implant (CI) users can alter the perception of music. Bimodal fitting not only provides bilateral hearing but can also improve auditory skills. This study was conducted to assess the impact of this amplification style on the emotional perception of music among children with hearing loss (HL). Twenty-five children with congenital severe to profound HL and unilateral CIs, 20 children with bimodal fitting, and 30 children with normal hearing participated in this study. Their emotional perceptions of music were measured using a method where children indicated happy or sad feelings induced by music by pointing to pictures of faces showing these emotions. Children with bimodal fitting obtained significantly higher mean scores than children with unilateral CIs for both happy and sad music items and in overall test scores (P < .001). Both groups with HL obtained significantly lower scores than children with normal hearing (P < .001). Bimodal fitting results in a better emotional perception of music compared to unilateral CI. Given the influence of music in neurological and linguistic development and social interactions, it is important to evaluate the possible benefits of bimodal fitting prescriptions for individuals with unilateral CIs. © The Author(s) 2015.

  12. Contributions of electric and acoustic hearing to bimodal speech and music perception.

    PubMed

    Crew, Joseph D; Galvin, John J; Landsberger, David M; Fu, Qian-Jie

    2015-01-01

    Cochlear implant (CI) users have difficulty understanding speech in noisy listening conditions and perceiving music. Aided residual acoustic hearing in the contralateral ear can mitigate these limitations. The present study examined contributions of electric and acoustic hearing to speech understanding in noise and melodic pitch perception. Data was collected with the CI only, the hearing aid (HA) only, and both devices together (CI+HA). Speech reception thresholds (SRTs) were adaptively measured for simple sentences in speech babble. Melodic contour identification (MCI) was measured with and without a masker instrument; the fundamental frequency of the masker was varied to be overlapping or non-overlapping with the target contour. Results showed that the CI contributes primarily to bimodal speech perception and that the HA contributes primarily to bimodal melodic pitch perception. In general, CI+HA performance was slightly improved relative to the better ear alone (CI-only) for SRTs but not for MCI, with some subjects experiencing a decrease in bimodal MCI performance relative to the better ear alone (HA-only). Individual performance was highly variable, and the contribution of either device to bimodal perception was both subject- and task-dependent. The results suggest that individualized mapping of CIs and HAs may further improve bimodal speech and music perception.

  13. Paternally expressed genes predominate in the placenta.

    PubMed

    Wang, Xu; Miller, Donald C; Harman, Rebecca; Antczak, Douglas F; Clark, Andrew G

    2013-06-25

    The discovery of genomic imprinting through studies of manipulated mouse embryos indicated that the paternal genome has a major influence on placental development. However, previous research has not demonstrated paternal bias in imprinted genes. We applied RNA sequencing to trophoblast tissue from reciprocal hybrids of horse and donkey, where genotypic differences allowed parent-of-origin identification of most expressed genes. Using this approach, we identified a core group of 15 ancient imprinted genes, of which 10 were paternally expressed. An additional 78 candidate imprinted genes identified by RNA sequencing also showed paternal bias. Pyrosequencing was used to confirm the imprinting status of six of the genes, including the insulin receptor (INSR), which may play a role in growth regulation with its reciprocally imprinted ligand, histone acetyltransferase-1 (HAT1), a gene involved in chromatin modification, and lymphocyte antigen 6 complex, locus G6C, a newly identified imprinted gene in the major histocompatibility complex. The 78 candidate imprinted genes displayed parent-of-origin expression bias in placenta but not fetus, and most showed less than 100% silencing of the imprinted allele. Some displayed variability in imprinting status among individuals. This variability results in a unique epigenetic signature for each placenta that contributes to variation in the intrauterine environment and thus presents the opportunity for natural selection to operate on parent-of-origin differential regulation. Taken together, these features highlight the plasticity of imprinting in mammals and the central importance of the placenta as a target tissue for genomic imprinting.

  14. Predominance of Ehrlichia ewingii in Missouri Dogs

    PubMed Central

    Liddell, Allison M.; Stockham, Steven L.; Scott, Michael A.; Sumner, John W.; Paddock, Christopher D.; Gaudreault-Keener, Monique; Arens, Max Q.; Storch, Gregory A.

    2003-01-01

    To investigate the species distribution of Ehrlichia present in Missouri dogs, we tested 78 dogs suspected of having acute ehrlichiosis and 10 healthy dogs. Blood from each dog was screened with a broad-range 16S rRNA gene PCR assay that detects known pathogenic species of Ehrlichia and Anaplasma. The species was determined by using species-specific PCR assays and nucleotide sequencing. Ehrlichia antibody testing was performed by using an indirect immunofluorescence assay with Ehrlichia chaffeensis as the antigenic substrate. The broad-range assay detected Ehrlichia or Anaplasma DNA in 20 (26%) of the symptomatic dogs and 2 (20%) of the asymptomatic dogs. E. ewingii accounted for 20 (91%), and E. chaffeensis accounted for 1 (5%) of the positives. Anaplasma phagocytophilum DNA was detected in one dog, and the sequences of regions of the 16S rRNA gene and the groESL operon amplified from the blood of this dog matched the published sequences of this organism. Antibodies reactive with E. chaffeensis were detected in 14 (67%) of the 21 PCR-positive dogs and in 12 (19%) of the 64 PCR-negative dogs. Combining the results of PCR and serology indicated that 33 (39%) of 85 evaluable dogs had evidence of past or current Ehrlichia infection. We conclude that E. ewingii is the predominant etiologic agent of canine ehrlichiosis in the areas of Missouri included in this survey. E. canis, a widely recognized agent of canine ehrlichiosis, was not detected in any animal. The finding of E. ewingii in asymptomatic dogs suggests that dogs could be a reservoir for this Ehrlichia species. PMID:14532192

  15. A bimodal spacecraft bus based on a cermet fueled heat pipe reactor

    SciTech Connect

    Polansky, G.F.; Rochow, R.F.; Gunther, N.G.; Bixler, C.H.

    1995-07-01

    Bimodal space reactor systems provide both thermal propulsion for the spacecraft orbital transfer and electrical power to the spacecraft bus once it is on station. These systems have the potential to increase both the available payload in high energy orbits and the available power to that payload. These increased mass and power capabilities can be used to either reduce mission cost by permitting the use of smaller launch vehicles or to provide increased mission performance from the current launch vehicle. A major barrier to the deployment of these bimodal systems has been the cost associated with their development. This paper describes a bimodal spacecraft bus with performance potential to permit more than 70% of the instrumented payload of the Titan IV/Centaur to be launched from the Atlas IIAS. The development cost is minimized by basing the design on existing component technologies.

  16. Tree cover bimodality in savannas and forests emerging from the switching between two fire dynamics.

    PubMed

    De Michele, Carlo; Accatino, Francesco

    2014-01-01

    Moist savannas and tropical forests share the same climatic conditions and occur side by side. Experimental evidences show that the tree cover of these ecosystems exhibits a bimodal frequency distribution. This is considered as a proof of savanna-forest bistability, predicted by dynamic vegetation models based on non-linear differential equations. Here, we propose a change of perspective about the bimodality of tree cover distribution. We show, using a simple matrix model of tree dynamics, how the bimodality of tree cover can emerge from the switching between two linear dynamics of trees, one in presence and one in absence of fire, with a feedback between fire and trees. As consequence, we find that the transitions between moist savannas and tropical forests, if sharp, are not necessarily catastrophic.

  17. A bimodal power and propulsion system based on cermet fuel and heat pipe energy transport

    SciTech Connect

    Polansky, G.F.; Gunther, N.A.; Rochow, R.F.; Bixler, C.H.

    1995-05-01

    Bimodal space reactor systems provide both thermal propulsion for the spacecraft orbital transfer and electrical power to the spacecraft bus once it is on station. These systems have the potential to increase both the available payload in high energy orbits and the available power to that payload. These increased mass and power capabilities can be used to either reduce mission cost by permitting the use of smaller launch vehicles or to provide increased mission performance from the current launch vehicle. A major barrier to the deployment of these bimodal systems has been the cost associated with their development. This paper describes a bimodal reactor system with performance potential to permit more than 70% of the instrumented payload of the Titan IV/Centaur to be launched from the Atlas IIAS. The development cost is minimized by basing the design on existing component technologies.

  18. Bimodal and trimodal multisensory enhancement: effects of stimulus onset and intensity on reaction time.

    PubMed

    Diederich, Adele; Colonius, Hans

    2004-11-01

    Manual reaction times to visual, auditory, and tactile stimuli presented simultaneously, or with a delay, were measured to test for multisensory interaction effects in a simple detection task with redundant signals. Responses to trimodal stimulus combinations were faster than those to bimodal combinations, which in turn were faster than reactions to unimodal stimuli. Response enhancement increased with decreasing auditory and tactile stimulus intensity and was a U-shaped function of stimulus onset asynchrony. Distribution inequality tests indicated that the multisensory interaction effects were larger than predicted by separate activation models, including the difference between bimodal and trimodal response facilitation. The results are discussed with respect to previous findings in a focused attention task and are compared with multisensory integration rules observed in bimodal and trimodal superior colliculus neurons in the cat and monkey.

  19. A bimodal spacecraft bus based on a cermet fueled heat pipe reactor

    NASA Astrophysics Data System (ADS)

    Polansky, G. F.; Rochow, R. F.; Gunther, N. G.; Bixler, C. H.

    Bimodal space reactor systems provide both thermal propulsion for the spacecraft orbital transfer and electrical power to the spacecraft bus once it is on station. These systems have the potential to increase both the available payload in high energy orbits and the available power to that payload. These increased mass and power capabilities can be used to either reduce mission cost by permitting the use of smaller launch vehicles or to provide increased mission performance from the current launch vehicle. A major barrier to the deployment of these bimodal systems has been the cost associated with their development. This paper describes a bimodal spacecraft bus with performance potential to permit more than 70% of the instrumented payload of the Titan 4/Centaur to be launched from the Atlas IIAS. The development cost is minimized by basing the design on existing component technologies.

  20. Structure and Dynamics of Bimodal Colloidal Dispersions in a Low-Molecular-Weight Polymer Solution.

    PubMed

    Zhang, Fan; Allen, Andrew J; Levine, Lyle E; Tsai, De-Hao; Ilavsky, Jan

    2017-03-21

    We present an experimental study of the structural and dynamical properties of bimodal, micrometer-sized colloidal dispersions (size ratio ≈ 2) in an aqueous solution of low-molecular-weight polymer (polyethylene glycol 2000) using synchrotron ultra-small angle X-ray scattering (USAXS) and USAXS-based X-ray photon correlation spectroscopy. We fixed the volume fraction of the large particles at 5% and systematically increased the volume fraction of the small particles from 0 to 5% to evaluate their effects on the structure and dynamics. The bimodal dispersions were homogenous through the investigated parameter space. We found that the partial structure factors can be satisfactorily retrieved for the bimodal colloidal dispersions using a Percus-Yevick hard-sphere potential when the size distributions of the particles were taken into account. We also found that the partial structure factor between the large particles did not exhibit a significant variation with increasing volume fraction of the small particles, whereas the isothermal compressibility of the binary mixture was found to decrease with increasing volume fraction of the small particles. The dynamics of single-component large-particle dispersion obey the principles of de Gennes narrowing, where the wave vector dependence of the interparticle diffusion coefficient is inversely proportional to the interparticle structure factor. The dynamics of the bimodal dispersions demonstrate a strong dependence on the fraction of small particles. We also made a comparison between the experimental effective dynamic viscosity of the bimodal dispersion with the theoretical predictions, which suggest that the complex mutual interactions between the large and small particles have a strong effect on the dynamic behaviors of bimodal dispersions.

  1. Auditory, visual, and bimodal data link displays and how they support pilot performance.

    PubMed

    Steelman, Kelly S; Talleur, Donald; Carbonari, Ronald; Yamani, Yusuke; Nunes, Ashley; McCarley, Jason S

    2013-06-01

    The design of data link messaging systems to ensure optimal pilot performance requires empirical guidance. The current study examined the effects of display format (auditory, visual, or bimodal) and visual display position (adjacent to instrument panel or mounted on console) on pilot performance. Subjects performed five 20-min simulated single-pilot flights. During each flight, subjects received messages from a simulated air traffic controller. Messages were delivered visually, auditorily, or bimodally. Subjects were asked to read back each message aloud and then perform the instructed maneuver. Visual and bimodal displays engendered lower subjective workload and better altitude tracking than auditory displays. Readback times were shorter with the two unimodal visual formats than with any of the other three formats. Advantages for the unimodal visual format ranged in size from 2.8 s to 3.8 s relative to the bimodal upper left and auditory formats, respectively. Auditory displays allowed slightly more head-up time (3 to 3.5 seconds per minute) than either visual or bimodal displays. Position of the visual display had only modest effects on any measure. Combined with the results from previous studies by Helleberg and Wickens and Lancaster and Casali the current data favor visual and bimodal displays over auditory displays; unimodal auditory displays were favored by only one measure, head-up time, and only very modestly. Data evinced no statistically significant effects of visual display position on performance, suggesting that, contrary to expectations, the placement of a visual data link display may be of relatively little consequence to performance.

  2. A Novel Feedback Loop That Controls Bimodal Expression of Genetic Competence

    PubMed Central

    Gamba, Pamela; Jonker, Martijs J.; Hamoen, Leendert W.

    2015-01-01

    Gene expression can be highly heterogeneous in isogenic cell populations. An extreme type of heterogeneity is the so-called bistable or bimodal expression, whereby a cell can differentiate into two alternative expression states. Stochastic fluctuations of protein levels, also referred to as noise, provide the necessary source of heterogeneity that must be amplified by specific genetic circuits in order to obtain a bimodal response. A classical model of bimodal differentiation is the activation of genetic competence in Bacillus subtilis. The competence transcription factor ComK activates transcription of its own gene, and an intricate regulatory network controls the switch to competence and ensures its reversibility. However, it is noise in ComK expression that determines which cells activate the ComK autostimulatory loop and become competent for genetic transformation. Despite its important role in bimodal gene expression, noise remains difficult to investigate due to its inherent stochastic nature. We adapted an artificial autostimulatory loop that bypasses all known ComK regulators to screen for possible factors that affect noise. This led to the identification of a novel protein Kre (YkyB) that controls the bimodal regulation of ComK. Interestingly, Kre appears to modulate the induction of ComK by affecting the stability of comK mRNA. The protein influences the expression of many genes, however, Kre is only found in bacteria that contain a ComK homologue and, importantly, kre expression itself is downregulated by ComK. The evolutionary significance of this new feedback loop for the reduction of transcriptional noise in comK expression is discussed. Our findings show the importance of mRNA stability in bimodal regulation, a factor that requires more attention when studying and modelling this non-deterministic developmental mechanism. PMID:26110430

  3. Clinical selection criteria for a second cochlear implant for bimodal listeners.

    PubMed

    Yoon, Yang-soo; Shin, You-Ree; Fu, Qian-Jie

    2012-09-01

    To compare the speech perception benefit, provided by a contralateral hearing aid (HA) or a second cochlear implant (CI). Repeated measures. A total of 25 adult subjects participated in the study, including 12 bilateral (10 female and 2 male patients) and 13 bimodal (6 female and 7 male subjects) users. All bilateral users were sequentially implanted. The bimodal users were separated into a poor group (n = 5, aided pure-tone average (PTA) of 55 dB HL or greater at audiometric frequencies of 1 kHz or lesser) and a good group (n = 8, aided PTA < 55 dB HL). Consonant, vowel, and sentence recognition was measured in quiet and noise at +5 dB and +10 dB signal-to-noise ratios (SNRs). Speech recognition performance was evaluated under three listening conditions: CI alone, HA alone, and CI+HA for bimodal users; first CI alone, second CI alone, and first CI + second CI for bilateral users when speech and noise were presented from the front. There was no significant difference in the binaural benefit between the good bimodal and bilateral groups in vowel and sentence recognition. However, the binaural benefit is significantly better in the bilateral group than in the poor bimodal group for all 3 speech measures. These results suggest that the aided pure-tone average at audiometric frequencies of 1 kHz or lesser may serve as one of the clinical criteria for the recommendation of whether bimodal patients should consider a second cochlear implant to maximize their binaural listening ability.

  4. Bimodal Multiparameter-Based Approach for Benign-Malignant Classification of Breast Tumors.

    PubMed

    Ara, Sharmin R; Alam, Farzana; Rahman, Md Hadiur; Akhter, Shabnam; Awwal, Rayhana; Hasan, Kamrul

    2015-07-01

    Proposed here is a breast tumor classification technique using conventional ultrasound B-mode imaging and a new elasticity imaging-based bimodal multiparameter index. A set of conventional ultrasound (US) and ultrasound elastography (UE) parameters are studied, and among those, the effective ones whose independent as well as combined performance is found satisfactory are selected. To improve the combined US performance, two new US parameters are proposed: edge diffusivity, which assesses edge blurriness to differentiate malignant from benign lesions, and the shape asymmetry factor, which quantifies tumor shape irregularity by comparing the tumor boundary with an ellipse fitted to the lesion. Then a new bimodal multiparameter characterization index is defined to discriminate 201 pathologically confirmed breast tumors of which 56 are malignant lesions, 79 are fibroadenomas, 42 are cysts and 24 are inflammatory lesions. The weights of the multiparameter bimodal index are optimally computed using a genetic algorithm (GA). To evaluate the performance variation of the index on different data sets, the tumors are categorized into three classes: malignant lesion versus fibroadenoma, malignant lesion versus fibroadenoma and cyst and malignant lesion versus fibroadenoma, cyst and inflammation. The test results reveal that the proposed bimodal index achieves satisfactory quality metrics (e.g., 94.64%-98.21% sensitivity, 97.24%-100.00% specificity and 96.52%-99.44% accuracy) for classification of the aforementioned three classes of breast tumors. Its performance is also observed to be better in totality of the quality metrics sensitivity, specificity, accuracy, positive predictive value and negative predictive value as compared with that of a conventional bimodal index as well as unimodal multiparameter indices based on US or UE. It is suggested that the proposed simple bimodal linear classifier may assist radiologists in better diagnosis of breast tumors and help reduce the

  5. Structure and Dynamics of Bimodal Colloidal Dispersions in a Low-Molecular-Weight Polymer Solution

    DOE PAGES

    Zhang, Fan; Allen, Andrew J.; Levine, Lyle E.; ...

    2017-02-24

    We present an experimental study of the structural and dynamical properties of bimodal, micrometersized colloidal dispersions (size ratio ≈ 2) in an aqueous solution of low-molecular weight polymer (polyethylene glycol 2000) using synchrotron ultra-small angle X-ray scattering (USAXS) and USAXSbased X-ray photon correlation spectroscopy. We fixed the volume fraction of the large particles at 5 % and systematically increased the volume fraction of the small particles from 0 % to 5 % to evaluate its effect on the structure and dynamics. The bimodal dispersions were homogenous through the investigated parameter space. We found that the partial structure factors can bemore » satisfactorily retrieved for the bimodal colloidal dispersions using a Percus-Yevick hard sphere potential when the particle size distributions of the particles were taken into account. We also found that the partial structure factor between the large particles does not exhibit significant variation with increasing volume fraction of small particles, whereas the isothermal compressibility of the binary mixture was found to decrease with increasing volume fraction of small particles. The dynamics of single-component large particle dispersion obey the principles of de Gennes narrowing, where the wave vector dependence of the interparticle diffusion coefficient is inversely proportional to the interparticle structure factor. The dynamics of the bimodal dispersions demonstrate strong dependence on the fraction of small particles. As a result, we also made a comparison between the experimental effective dynamic viscosity of the bimodal dispersion with theoretical predictions, which suggest that the complex mutual interactions between large and small particles have a strong effect on the dynamic behaviors of bimodal dispersions.« less

  6. Influence of Controlled Cooling in Bimodal Scaffold Fabrication Using Polymers with Different Melting Temperatures.

    PubMed

    Lara-Padilla, Hernan; Mendoza-Buenrostro, Christian; Cardenas, Diego; Rodriguez-Garcia, Aida; Rodriguez, Ciro A

    2017-06-11

    The combination of different materials and capabilities to manufacture at several scales open new possibilities in scaffold design for bone regeneration. This work is focused on bimodal scaffolds that combine polylactic acid (PLA) melt extruded strands with polycaprolactone (PCL) electrospun fibers. This type of bimodal scaffold offers better mechanical properties, compared to the use of PCL for the extruded strands, and provides potential a means for controlled drug and/or growth factor delivery through the electrospun fibers. The technologies of fused deposition modeling (FDM) and electrospinning were combined to create 3D bimodal constructs. The system uses a controlled cooling system allowing the combination of polymers with different melting temperatures to generate integrated scaffold architecture. The thermoplastic polymers used in the FDM process enhance the mechanical properties of the bimodal scaffold and control the pore structure. Integrated layers of electrospun microfibers induce an increase of the surface area for cell culture purposes, as well as potential in situ controlled drug and/or growth factor delivery. The proposed bimodal scaffolds (PLA extruded strands and PCL electrospun fibers) show appropriate morphology and better mechanical properties when compared to the use of PCL extruded strands. On average, bimodal scaffolds with overall dimensions of 30 × 30 × 2.4 mm³ (strand diameter of 0.5 mm, strand stepover of 2.5 mm, pore size of 2 mm, and layer height of 0.3 mm) showed scaffold stiffness of 23.73 MPa and compression strength of 3.85 MPa. A cytotoxicity assay based human fibroblasts showed viability of the scaffold materials.

  7. Bimodal benefit depends on the performance difference between a cochlear implant and a hearing aid.

    PubMed

    Yoon, Yang-Soo; Shin, You-Ree; Gho, Jae-Sook; Fu, Qian-Jie

    2015-05-01

    Objectives The present study characterizes the relationship between bimodal benefit and hearing aid (HA) performance, cochlear implant (CI) performance, and the difference in the performances of the two devices. Methods Fourteen adult bimodal listeners participated in the study. Consonant, vowel, and sentence recognition were measured in quiet and noise (at a +5 and +10 dB signal-to-noise ratio (SNR)) with an HA alone, a CI alone, and with the combined use of an HA and CI in each listener. Speech and noise were presented directly in front of the listener. Results The correlation analyses showed that bimodal benefit was significantly associated with the difference in performances of a CI and an HA in all testing materials, with HA-alone performance in vowel recognition, and with CI-alone performance in sentence recognition. However, regression analyses showed that the independent contribution of the difference in performance across ears to bimodal benefit was significant, irrespective of the testing material or the SNR: the smaller the difference, the greater the benefit. Further, the independent contributions of HA-only performance and CI-alone performance were not significant factors in predicting the existence of bimodal benefit across testing materials and SNRs when the effect of the difference between CI and HA performance was removed from the model. Conclusion The results suggest that bimodal benefit is limited by how effectively the modalities integrate, rather than HA-only or CI-alone performance, and that this integration is facilitated when the performances of the modalities are similar.

  8. Influence of Controlled Cooling in Bimodal Scaffold Fabrication Using Polymers with Different Melting Temperatures

    PubMed Central

    Lara-Padilla, Hernan; Mendoza-Buenrostro, Christian; Cardenas, Diego; Rodriguez-Garcia, Aida; Rodriguez, Ciro A.

    2017-01-01

    The combination of different materials and capabilities to manufacture at several scales open new possibilities in scaffold design for bone regeneration. This work is focused on bimodal scaffolds that combine polylactic acid (PLA) melt extruded strands with polycaprolactone (PCL) electrospun fibers. This type of bimodal scaffold offers better mechanical properties, compared to the use of PCL for the extruded strands, and provides potential a means for controlled drug and/or growth factor delivery through the electrospun fibers. The technologies of fused deposition modeling (FDM) and electrospinning were combined to create 3D bimodal constructs. The system uses a controlled cooling system allowing the combination of polymers with different melting temperatures to generate integrated scaffold architecture. The thermoplastic polymers used in the FDM process enhance the mechanical properties of the bimodal scaffold and control the pore structure. Integrated layers of electrospun microfibers induce an increase of the surface area for cell culture purposes, as well as potential in situ controlled drug and/or growth factor delivery. The proposed bimodal scaffolds (PLA extruded strands and PCL electrospun fibers) show appropriate morphology and better mechanical properties when compared to the use of PCL extruded strands. On average, bimodal scaffolds with overall dimensions of 30 × 30 × 2.4 mm3 (strand diameter of 0.5 mm, strand stepover of 2.5 mm, pore size of 2 mm, and layer height of 0.3 mm) showed scaffold stiffness of 23.73 MPa and compression strength of 3.85 MPa. A cytotoxicity assay based human fibroblasts showed viability of the scaffold materials. PMID:28773000

  9. Binaural-Bimodal Fitting or Bilateral Implantation for Managing Severe to Profound Deafness: A Review

    PubMed Central

    Ching, T. Y. C.; van Wanrooy, E.; Dillon, H.

    2007-01-01

    There are now many recipients of unilateral cochlear implants who have usable residual hearing in the nonimplanted ear. To avoid auditory deprivation and to provide binaural hearing, a hearing aid or a second cochlear implant can be fitted to that ear. This article addresses the question of whether better binaural hearing can be achieved with binaural/bimodal fitting (combining a cochlear implant and a hearing aid in opposite ears) or bilateral implantation. In the first part of this article, the rationale for providing binaural hearing is examined. In the second part, the literature on the relative efficacy of binaural/bimodal fitting and bilateral implantation is reviewed. Most studies on comparing either mode of bilateral stimulation with unilateral implantation reported some binaural benefits in some test conditions on average but revealed that some individuals benefited, whereas others did not. There were no controlled comparisons between binaural/bimodal fitting and bilateral implantation and no evidence to support the efficacy of one mode over the other. In the third part of the article, a crossover trial of two adults who had binaural/bimodal fitting and who subsequently received a second implant is reported. The findings at 6 and 12 months after they received their second implant indicated that binaural function developed over time, and the extent of benefit depended on which abilities were assessed for the individual. In the fourth and final parts of the article, clinical issues relating to candidacy for binaural/bimodal fitting and strategies for bimodal fitting are discussed with implications for future research. PMID:17709573

  10. Effect of a bimodal initial particle volume fraction perturbation in an explosive dispersal of particles

    NASA Astrophysics Data System (ADS)

    Ouellet, Frederick; Annamalai, Subramanian; Rollin, Bertrand

    2017-01-01

    Explosive dispersal of particles is a complex multiphase phenomenon that has yet to be fully understood. As the particle cloud disperses at high speed, it experiences multiphase instabilities related to Richtmyer-Meshkov (RM) and Rayleigh-Taylor (RT) instabilities when interacting with the blast-wave structure. This paper reports the results of a numerical experiment where the effect of bimodal perturbations in the initial particle volume fraction is studied. Results indicate that a signature of the initial perturbation profile remains in the particle cloud throughout the observed time, and that adding a bimodal perturbation increases the width of the cloud when compared to a uniform volume fraction distribution.

  11. An Illumination Invariant Bimodal Method Employing Discriminant Features for Face Recognition

    NASA Astrophysics Data System (ADS)

    Wu, Jiying; Ruan, Qiuqi; An, Gaoyun

    A novel bimodal method for face recognition under low-level lighting conditions is proposed. It fuses an enhanced gray level imageand an illumination-invariant geometric image at the feature-level. To further improve the recognition performance under large variations in attributions such as poses and expressions, discriminant features are extracted from source images using the wavelet transform-based method. Features are adaptively fused to reconstruct the final face sample. Then FLD is used to generate a supervised discriminant space for the classification task. Experiments show that the bimodal method outperforms conventional methods under complex conditions.

  12. Dual Phase Separation for Synthesis of Bimodal Meso/Macroporous Carbon Monoliths

    SciTech Connect

    Liang, Chengdu; Dai, Sheng

    2009-01-01

    Polymerization-induced spinodal decomposition was conducted in glycolic solutions of phloroglucinol/formaldehyde (PF) copolymer and poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) (PEO-PPO-PEO) to synthesize bicontinuous macroporous morphologies with micro-domains from 0.5 to 6 microns. The polymeric materials were further carbonized at elevated temperature to yield bimodal meso/macroporous carbon monoliths after the thermal decomposition of the PEO-PPO-PEO template. The bimodal porous nature of the resultant carbon monoliths resulted from the dual phase separation, in which spinodal decomposition and microphase separation occurred simultaneously. We demonstrated the tunability of macropores without alteration of mesopore sizes.

  13. Magnetic conjugated polymer nanoparticles as bimodal imaging agents.

    PubMed

    Howes, Philip; Green, Mark; Bowers, Alex; Parker, David; Varma, Gopal; Kallumadil, Mathew; Hughes, Mary; Warley, Alice; Brain, Anthony; Botnar, Rene

    2010-07-21

    Hybrid nanoparticles which incorporate multiple functionalities, such as fluorescence and magnetism, can exhibit enhanced efficiency and versatility by performing several tasks in parallel. In this study, magnetic-fluorescent semiconductor polymer nanospheres (MF-SPNs) have been synthesized by encapsulation of hydrophobic conjugated polymers and iron oxide nanoparticles in phospholipid micelles. Four fluorescent conjugated polymers were used, yielding aqueous dispersions of nanoparticles which emit across the visible spectrum. The MF-SPNs were shown to be magnetically responsive and simultaneously fluorescent. In MRI studies, they were seen to have a shortening effect on the transverse T(2)* relaxation time, which demonstrates their potential as an MR contrast agent. Finally, successful uptake of the MF-SPNs by SH-SY5Y neuroblastoma cells was demonstrated, and they were seen to behave as bright and stable fluorescent markers. There was no evidence of toxicity or adverse affect on cell growth.

  14. Mandarin Tone and Vowel Recognition in Cochlear Implant Users: Effects of Talker Variability and Bimodal Hearing.

    PubMed

    Chang, Yi-Ping; Chang, Ronald Y; Lin, Chun-Yi; Luo, Xin

    2016-01-01

    For cochlear implant (CI) users with residual low-frequency acoustic hearing in the nonimplanted ear, bimodal hearing combining the use of a CI and a contralateral hearing aid (HA) may provide more salient talker voice cues than CI alone to handle the variability of talker identity across trials. This study tested the effects of talker variability, bimodal hearing, and their interaction on response accuracy and time of CI users' Mandarin tone, vowel, and syllable recognition (i.e., combined Mandarin tone and vowel recognition in this study). Fifteen prelingually deafened native Mandarin-speaking CI users (at age 20 or lower) participated in this study. Four talkers each produced six Mandarin single-vowel syllables in four lexical tones. The stimuli were presented in quiet via a single loudspeaker. To study the effects of talker variability, Mandarin tone, vowel, and syllable recognition was tested in two presentation conditions: with stimuli blocked according to talker (blocked-talker condition) or mixed across talkers from trial to trial (mixed-talker condition). To explore the effects of bimodal hearing, two processor conditions were tested: CI alone or CI + HA. The cumulative response time was recorded as an indirect indicator of the cognitive load or listening effort in each condition. The correlations were computed between demographic/hearing factors (e.g., hearing thresholds in the nonimplanted ear) and bimodal performance/benefits (where bimodal benefits refer to the performance differences between CI alone and CI + HA). Mandarin tone recognition with both CI alone and CI + HA was significantly poorer in the mixed-talker condition than in the blocked-talker condition, while vowel recognition was comparable in the two presentation conditions. Bimodal hearing significantly improved Mandarin tone recognition but not vowel recognition. Mandarin syllable recognition was significantly affected by both talker variability and bimodal hearing. The cumulative response

  15. Determination of Predominance of Influenza Virus Strains in the Americas.

    PubMed

    Azziz-Baumgartner, Eduardo; Garten, Rebecca J; Palekar, Rakhee; Cerpa, Mauricio; Mirza, Sara; Ropero, Alba Maria; Palomeque, Francisco S; Moen, Ann; Bresee, Joseph; Shaw, Michael; Widdowson, Marc-Alain

    2015-07-01

    During 2001-2014, predominant influenza A(H1N1) and A(H3N2) strains in South America predominated in all or most subsequent influenza seasons in Central and North America. Predominant A(H1N1) and A(H3N2) strains in North America predominated in most subsequent seasons in Central and South America. Sharing data between these subregions may improve influenza season preparedness.

  16. Determination of Predominance of Influenza Virus Strains in the Americas

    PubMed Central

    Garten, Rebecca J.; Palekar, Rakhee; Cerpa, Mauricio; Mirza, Sara; Ropero, Alba Maria; Palomeque, Francisco S.; Moen, Ann; Bresee, Joseph; Shaw, Michael; Widdowson, Marc-Alain

    2015-01-01

    During 2001–2014, predominant influenza A(H1N1) and A(H3N2) strains in South America predominated in all or most subsequent influenza seasons in Central and North America. Predominant A(H1N1) and A(H3N2) strains in North America predominated in most subsequent seasons in Central and South America. Sharing data between these subregions may improve influenza season preparedness. PMID:26079140

  17. Age, petrogenesis, and tectonic setting of the Permian bimodal volcanic rocks in the eastern Jiamusi Massif, NE China

    NASA Astrophysics Data System (ADS)

    Bi, Jun-Hui; Ge, Wen-Chun; Yang, Hao; Wang, Zhi-Hui; Dong, Yu; Liu, Xi-Wen; Ji, Zheng

    2017-02-01

    We present new in situ zircon U-Pb and Hf isotope, whole-rock geochemical, and Sr-Nd isotopic data for volcanic rocks from the Jiejinkou and Baoqing areas in the eastern Jiamusi Massif. These volcanic rocks are bimodal and consist of basalts, basaltic andesites, rhyolites, and rhyolitic tuffs that can be subdivided into mafic and silicic groups. Zircon U-Pb dating by LA-ICP-MS indicates that these volcanic rocks were erupted between the Early and Middle Permian (290-267 Ma). The mafic rocks in this area have positive εNd(t) (+0.07 to +6.43) values, and are enriched in light rare earth elements (LREEs) and depleted in heavy REE, Nb, and Ta. From these rocks, the meta-basalt of Jinlu and basaltic andesite of Taipinggou and Haojiatun were derived from parental magmas generated by the partial melting of depleted mantle wedge material that was metasomatized by subduction-related melts. These magmas then underwent variable degrees of fractional crystallization and assimilated insignificant amounts of crustal material. The meta-basalt of Liming likely originated from the metasomatized mantle-derived melts hybridized by the convective asthenosphere during the evolution of the magmas. In comparison, the silicic rocks have negative εNd(t) and variable zircon εHf(t) values, are enriched in the large-ion lithophile elements (LILEs) and LREE, and are depleted in high-field-strength elements (e.g., Nb, Ta, and Ti), yielding arc-like geochemical signatures. The geochemical and zircon εHf(t) characteristics of Jiangfeng and Longtouqiao rhyolites are indicative of formation from magmas generated by the partial melting of mafic lower crustal material, whereas the Liming meta-rhyolite was probably produced from a source involving some depleted mantle components. The bimodal volcanic rocks provide convincing evidence that the Early-Middle Permian volcanism in the Jiamusi Massif occurred in an extensional environment probably associated with slab break-off during the westward

  18. A One-year, Short-Stay Crewed Mars Mission Using Bimodal Nuclear Thermal Electric Propulsion (BNTEP) - A Preliminary Assessment

    NASA Technical Reports Server (NTRS)

    Burke, Laura M.; Borowski, Stanley K.; McCurdy, David R.; Packard, Thomas W.

    2013-01-01

    A crewed mission to Mars poses a significant challenge in dealing with the physiological issues that arise with the crew being exposed to a near zero-gravity environment as well as significant solar and galactic radiation for such a long duration. While long surface stay missions exceeding 500 days are the ultimate goal for human Mars exploration, short round trip, short surface stay missions could be an important intermediate step that would allow NASA to demonstrate technology as well as study the physiological effects on the crew. However, for a 1-year round trip mission, the outbound and inbound hyperbolic velocity at Earth and Mars can be very large resulting in a significant propellant requirement for a high thrust system like Nuclear Thermal Propulsion (NTP). Similarly, a low thrust Nuclear Electric Propulsion (NEP) system requires high electrical power levels (10 megawatts electric (MWe) or more), plus advanced power conversion technology to achieve the lower specific mass values needed for such a mission. A Bimodal Nuclear Thermal Electric Propulsion (BNTEP) system is examined here that uses three high thrust Bimodal Nuclear Thermal Rocket (BNTR) engines allowing short departure and capture maneuvers. The engines also generate electrical power that drives a low thrust Electric Propulsion (EP) system used for efficient interplanetary transit. This combined system can help reduce the total launch mass, system and operational requirements that would otherwise be required for equivalent NEP or Solar Electric Propulsion (SEP) mission. The BNTEP system is a hybrid propulsion concept where the BNTR reactors operate in two separate modes. During high-thrust mode operation, each BNTR provides 10's of kilo-Newtons of thrust at reasonably high specific impulse (Isp) of 900 seconds for impulsive transplanetary injection and orbital insertion maneuvers. When in power generation/EP mode, the BNTR reactors are coupled to a Brayton power conversion system allowing each

  19. A One-year, Short-Stay Crewed Mars Mission Using Bimodal Nuclear Thermal Electric Propulsion (BNTEP) - A Preliminary Assessment

    NASA Technical Reports Server (NTRS)

    Burke, Laura A.; Borowski, Stanley K.; McCurdy, David R.; Packard, Thomas W.

    2013-01-01

    A crewed mission to Mars poses a signi cant challenge in dealing with the physiolog- ical issues that arise with the crew being exposed to a near zero-gravity environment as well as signi cant solar and galactic radiation for such a long duration. While long sur- face stay missions exceeding 500 days are the ultimate goal for human Mars exploration, short round trip, short surface stay missions could be an important intermediate step that would allow NASA to demonstrate technology as well as study the physiological e ects on the crew. However, for a 1-year round trip mission, the outbound and inbound hy- perbolic velocity at Earth and Mars can be very large resulting in a signi cant propellant requirement for a high thrust system like Nuclear Thermal Propulsion (NTP). Similarly, a low thrust Nuclear Electric Propulsion (NEP) system requires high electrical power lev- els (10 megawatts electric (MWe) or more), plus advanced power conversion technology to achieve the lower speci c mass values needed for such a mission. A Bimodal Nuclear Thermal Electric Propulsion (BNTEP) system is examined here that uses three high thrust Bimodal Nuclear Thermal Rocket (BNTR) engines allowing short departure and capture maneuvers. The engines also generate electrical power that drives a low thrust Electric Propulsion (EP) system used for ecient interplanetary transit. This combined system can help reduce the total launch mass, system and operational requirements that would otherwise be required for equivalent NEP or Solar Electric Propulsion (SEP) mission. The BNTEP system is a hybrid propulsion concept where the BNTR reactors operate in two separate modes. During high-thrust mode operation, each BNTR provides 10's of kilo- Newtons of thrust at reasonably high speci c impulse (Isp) of 900 seconds for impulsive trans-planetary injection and orbital insertion maneuvers. When in power generation / EP mode, the BNTR reactors are coupled to a Brayton power conversion system allowing each

  20. Intensity and degree of segregation in bimodal and multimodal grain size distributions

    NASA Astrophysics Data System (ADS)

    Katra, Itzhak; Yizhaq, Hezi

    2017-08-01

    The commonly used grain size analysis technique which applies moments (sorting, skewness and kurtosis) is less useful in the case of sediments with bimodal size distributions. Herein we suggest a new simple method for analyzing the degree of grain size segregation in sand-sized sediment that has clear bimodal size distributions. Two main features are used to characterize the bimodal distribution: grain diameter segregation, which is the normalized difference between coarse and fine grain diameters, and the frequency segregation which is the normalized difference in frequencies between two modes. The new defined indices can be calculated from frequency plot curves and can be graphically represented on a two dimensional coordinate system showing the dynamical aspects of the size distribution. The results enable comparison between granular samples from different locations and/or times to shed new light on the dynamic processes involved in grain size segregation of sediments. We demonstrate here the use of this method to analyze bimodal distributions of aeolian granular samples mostly from aeolian megaripples. Six different aeolian cases were analyzed to highlight the method's applicability, which is relevant to wide research themes in the Earth and environmental sciences, and can furthermore be easily adapted to analyze polymodal grain size distributions.

  1. Teleporting a state inside a single bimodal high-Q cavity

    SciTech Connect

    Pires, Geisa; Baseia, B.; Avelar, A.T.; Almeida, N.G. de

    2005-06-15

    We discuss a simplified scheme to teleport a state from one mode to another of the same bimodal cavity, with these two modes having distinct frequencies and orthogonal polarizations. The scheme employs two two-level (Rydberg) atoms plus classical fields (Ramsey zones) and selective atomic state detectors. The result has potential use for the manipulation of quantum information processing.

  2. Testing for bimodality in frequency distributions of data suggesting polymorphisms of drug metabolism--hypothesis testing.

    PubMed Central

    Jackson, P R; Tucker, G T; Woods, H F

    1989-01-01

    1. The theory of methods of hypothesis testing in relation to the detection of bimodality in density distributions is discussed. 2. Practical problems arising from these methods are outlined. 3. The power of three methods of hypothesis testing was compared using simulated data from bimodal distributions with varying separation between components. None of the methods could determine bimodality until the separation between components was 2 standard deviation units and could only do so reliably (greater than 90%) when the separation was as great as 4-6 standard deviation units. 4. The robustness of a parametric and a non-parametric method of hypothesis testing was compared using simulated unimodal distributions known to deviate markedly from normality. Both methods had a high frequency of falsely indicating bimodality with distributions where the components had markedly differing variances. 5. A further test of robustness using power transformation of data from a normal distribution showed that the algorithms could accurately determine unimodality only when the skew of the distribution was in the range 0-1.45. PMID:2611088

  3. Quality of life in bimodal hearing users (unilateral cochlear implants and contralateral hearing aids).

    PubMed

    Farinetti, A; Roman, S; Mancini, J; Baumstarck-Barrau, K; Meller, R; Lavieille, J P; Triglia, J M

    2015-11-01

    The main objective was to evaluate the bimodal self-rated benefits on auditory performance under real conditions and the quality of life in two groups of cochlear-implanted adults, with or without a contralateral hearing aid. The secondary objective was to investigate correlations between the use of a hearing aid and residual hearing on the non-implanted ear. This retrospective study was realized between 2000 and 2010 in two referral centers. A population of 183 postlingually deaf adults, implanted with a cochlear experience superior to 6 months, was selected. The Speech, Spatial, and other Qualities of Hearing Scale were administered to evaluate the auditory performances, and the Nijmegen Cochlear Implant Questionnaire to evaluate the quality of life. The population was divided into two groups: a group with unilateral cochlear implants (Cochlear Implant-alone, n = 54), and a bimodal group with a cochlear implant and a contralateral hearing aid (n = 62). Both groups were similar in terms of auditory deprivation duration, duration of cochlear implant use, and pure-tone average on the implanted ear. There was a significant difference in terms of pure-tone average on low and low-to-mid frequencies on the non-implanted ear. The scores on both questionnaires showed an improvement in the basic sound perception and quality of social activities for the bimodal group. The results suggest that the bimodal stimulation (cochlear implant and contralateral hearing aid) improved auditory perception in quiet and the quality of life domain of social activities.

  4. The role of the dorsolateral prefrontal cortex in bimodal divided attention: two transcranial magnetic stimulation studies.

    PubMed

    Johnson, Jennifer Adrienne; Strafella, Antonio P; Zatorre, Robert J

    2007-06-01

    The neural processes underlying the ability to divide attention between multiple sensory modalities remain poorly understood. To investigate the role of the dorsolateral prefrontal cortex (DLPFC) in bimodal divided attention, we completed two repetitive transcranial magnetic stimulation (rTMS) studies. We tested the hypothesis that the DLPFC is necessary in the ability to divide attention across modalities. This hypothesis originated as a result of a previous fMRI study in which the posterior DLPFC was active during a bimodal divided attention condition [Johnson, J. A., & Zatorre, R. J. Neural substrates for dividing and focusing attention between simultaneous auditory and visual events. Neuroimage, 2006]. In the current experiments, two separate groups of subjects underwent 10 min of slow rTMS to temporarily disrupt function of the DLPFC. In both groups, the ability to divide attention between unrelated auditory and visual stimuli decreased following DLPFC disruption compared to control site stimulation. Specifically, the ability to divide attention between modalities was hindered, leading to a pattern of behavior similar to bimodal selective attention (ability to attend to one or the other modality but not both). We discuss possible roles of the posterior DLPFC in bimodal divided attention and conclude that the area may be functioning to support the increased working memory load associated with divided, compared to selective attention.

  5. Resonant tunneling and the bimodal symmetric fission of sup 258 Fm

    SciTech Connect

    Bhandari, B.S. )

    1991-02-25

    The concept of resonant tunneling is invoked to explain the sharp drop in the measured spontaneous-fission half-life when going from {sup 256}Fm to {sup 258}Fm. Various consequences of such a suggestion on the other observed characteristics of the bimodal symmetric fission of {sup 258}Fm are briefly discussed.

  6. Self-Injurious Behavior: A Bi-Modal Treatment Approach to Working with Adolescent Females.

    ERIC Educational Resources Information Center

    Stone, Judy A.; Sias, Shari M.

    2003-01-01

    The topic of self-injurious behavior (SIB), particularly among female adolescents, has been gaining widespread attention in mainstream culture. However, limited research has been generated examining effective treatment modalities. Given the lack of information concerning treatment models, this article presents a bi-modal treatment approach with a…

  7. Cross-Frequency Integration for Consonant and Vowel Identification in Bimodal Hearing

    ERIC Educational Resources Information Center

    Kong, Ying-Yee; Braida, Louis D.

    2011-01-01

    Purpose: Improved speech recognition in binaurally combined acoustic-electric stimulation (otherwise known as "bimodal hearing") could arise when listeners integrate speech cues from the acoustic and electric hearing. The aims of this study were (a) to identify speech cues extracted in electric hearing and residual acoustic hearing in the…

  8. Phenotypic Diversity Using Bimodal and Unimodal Expression of Stress Response Proteins.

    PubMed

    Garcia-Bernardo, Javier; Dunlop, Mary J

    2016-05-24

    Populations of cells need to express proteins to survive the sudden appearance of stressors. However, these mechanisms may be taxing. Populations can introduce diversity, allowing individual cells to stochastically switch between fast-growing and stress-tolerant states. One way to achieve this is to use genetic networks coupled with noise to generate bimodal distributions with two distinct subpopulations, each adapted to a stress condition. Another survival strategy is to rely on random fluctuations in gene expression to produce continuous, unimodal distributions of the stress response protein. To quantify the environmental conditions where bimodal versus unimodal expression is beneficial, we used a differential evolution algorithm to evolve optimal distributions of stress response proteins given environments with sudden fluctuations between low and high stress. We found that bimodality evolved for a large range of environmental conditions. However, we asked whether these findings were an artifact of considering two well-defined stress environments (low and high stress). As noise in the environment increases, or when there is an intermediate environment (medium stress), the benefits of bimodality decrease. Our results indicate that under realistic conditions, a continuum of resistance phenotypes generated through a unimodal distribution is sufficient to ensure survival without a high cost to the population.

  9. The Bi-Modal Organization: Balancing Autopoiesis and Fluid Social Networks for Sustainability

    ERIC Educational Resources Information Center

    Smith, Peter A. C.; Sharicz, Carol Ann

    2013-01-01

    Purpose: The purpose of this paper is to assist an organization to restructure as a bi-modal organization in order to achieve sustainability in today's highly complex business world. Design/methodology/approach: The paper is conceptual and is based on relevant literature and the authors' research and practice. Findings: Although fluid…

  10. Deaf Parents of Cochlear-Implanted Children: Beliefs on Bimodal Bilingualism

    ERIC Educational Resources Information Center

    Mitchiner, Julie Cantrell

    2015-01-01

    This study investigated 17 Deaf families in North America with cochlear-implanted children about their attitudes, beliefs, and practices on bimodal bilingualism (defined as using both a visual/manual language and an aural/oral language) in American Sign Language (ASL) and English. A survey and follow-up interviews with 8 families were conducted.…

  11. Bimodal Emotion Congruency Is Critical to Preverbal Infants' Abstract Rule Learning

    ERIC Educational Resources Information Center

    Tsui, Angeline Sin Mei; Ma, Yuen Ki; Ho, Anna; Chow, Hiu Mei; Tseng, Chia-huei

    2016-01-01

    Extracting general rules from specific examples is important, as we must face the same challenge displayed in various formats. Previous studies have found that bimodal presentation of grammar-like rules (e.g. ABA) enhanced 5-month-olds' capacity to acquire a rule that infants failed to learn when the rule was presented with visual presentation of…

  12. Novel pitch-based carbons with bimodal distribution of uniform mesopores.

    PubMed

    Gierszal, Kamil P; Jaroniec, Mietek

    2004-11-21

    A new method is proposed for the synthesis of pitch-based carbons with bimodal distribution of uniform mesopores formed by co-imprinting of spherical silica colloids and hexagonally ordered mesoporous particles of SBA-15 into mesophase pitch particles and subsequent silica dissolution.

  13. Near-Infrared Squaraine Dye Encapsulated Micelles for in Vivo Fluorescence and Photoacoustic Bimodal Imaging.

    PubMed

    Sreejith, Sivaramapanicker; Joseph, James; Lin, Manjing; Menon, Nishanth Venugopal; Borah, Parijat; Ng, Hao Jun; Loong, Yun Xian; Kang, Yuejun; Yu, Sidney Wing-Kwong; Zhao, Yanli

    2015-06-23

    Combined near-infrared (NIR) fluorescence and photoacoustic imaging techniques present promising capabilities for noninvasive visualization of biological structures. Development of bimodal noninvasive optical imaging approaches by combining NIR fluorescence and photoacoustic tomography demands suitable NIR-active exogenous contrast agents. If the aggregation and photobleaching are prevented, squaraine dyes are ideal candidates for fluorescence and photoacoustic imaging. Herein, we report rational selection, preparation, and micelle encapsulation of an NIR-absorbing squaraine dye (D1) for in vivo fluorescence and photoacoustic bimodal imaging. D1 was encapsulated inside micelles constructed from a biocompatible nonionic surfactant (Pluoronic F-127) to obtain D1-encapsulated micelles (D1(micelle)) in aqueous conditions. The micelle encapsulation retains both the photophysical features and chemical stability of D1. D1(micelle) exhibits high photostability and low cytotoxicity in biological conditions. Unique properties of D1(micelle) in the NIR window of 800-900 nm enable the development of a squaraine-based exogenous contrast agent for fluorescence and photoacoustic bimodal imaging above 820 nm. In vivo imaging using D1(micelle), as demonstrated by fluorescence and photoacoustic tomography experiments in live mice, shows contrast-enhanced deep tissue imaging capability. The usage of D1(micelle) proven by preclinical experiments in rodents reveals its excellent applicability for NIR fluorescence and photoacoustic bimodal imaging.

  14. Computational Aeroelastic Analysis of Ares Crew Launch Vehicle Bi-Modal Loading

    NASA Technical Reports Server (NTRS)

    Massey, Steven J.; Chwalowski, Pawel

    2010-01-01

    A Reynolds averaged Navier-Stokes analysis, with and without dynamic aeroelastic effects, is presented for the Ares I-X launch vehicle at transonic Mach numbers and flight Reynolds numbers for two grid resolutions and two angles of attack. The purpose of the study is to quantify the force and moment increment imparted by the sudden transition from fully separated flow around the crew module - service module junction to that of the bi-modal flow state in which only part of the flow reattaches. The bi-modal flow phenomenon is of interest to the guidance, navigation and control community because it causes a discontinuous jump in forces and moments. Computations with a rigid structure at zero zero angle of attack indicate significant increases in normal force and pitching moment. Dynamic aeroelastic computations indicate the bi-modal flow state is insensitive to vehicle flexibility due to the resulting deflections imparting only very small changes in local angle of attack. At an angle of attack of 2.5deg, the magnitude of the pitching moment increment resulting from the bi-modal state nearly triples, while occurring at a slightly lower Mach number. Significant grid induced variations between the solutions indicate that further grid refinement is warranted.

  15. Deaf Parents of Cochlear-Implanted Children: Beliefs on Bimodal Bilingualism

    ERIC Educational Resources Information Center

    Mitchiner, Julie Cantrell

    2015-01-01

    This study investigated 17 Deaf families in North America with cochlear-implanted children about their attitudes, beliefs, and practices on bimodal bilingualism (defined as using both a visual/manual language and an aural/oral language) in American Sign Language (ASL) and English. A survey and follow-up interviews with 8 families were conducted.…

  16. Song Recognition by Young Children with Cochlear Implants: Comparison between Unilateral, Bilateral, and Bimodal Users

    ERIC Educational Resources Information Center

    Bartov, Tamar; Most, Tova

    2014-01-01

    Purpose: To examine song identification by preschoolers with normal hearing (NH) versus preschoolers with cochlear implants (CIs). Method: Participants included 45 children ages 3;8-7;3 (years;months): 12 with NH and 33 with CIs, including 10 with unilateral CI, 14 with bilateral CIs, and 9 bimodal users (CI-HA) with unilateral CI and…

  17. Parallel Bimodal Bilingual Acquisition: A Hearing Child Mediated in a Deaf Family

    ERIC Educational Resources Information Center

    Cramér-Wolrath, Emelie

    2013-01-01

    The aim of this longitudinal case study was to describe bimodal and bilingual acquisition in a hearing child, Hugo, especially the role his Deaf family played in his linguistic education. Video observations of the family interactions were conducted from the time Hugo was 10 months of age until he was 40 months old. The family language was Swedish…

  18. The role of continuous low-frequency harmonicity cues for interrupted speech perception in bimodal hearing.

    PubMed

    Oh, Soo Hee; Donaldson, Gail S; Kong, Ying-Yee

    2016-04-01

    Low-frequency acoustic cues have been shown to enhance speech perception by cochlear-implant users, particularly when target speech occurs in a competing background. The present study examined the extent to which a continuous representation of low-frequency harmonicity cues contributes to bimodal benefit in simulated bimodal listeners. Experiment 1 examined the benefit of restoring a continuous temporal envelope to the low-frequency ear while the vocoder ear received a temporally interrupted stimulus. Experiment 2 examined the effect of providing continuous harmonicity cues in the low-frequency ear as compared to restoring a continuous temporal envelope in the vocoder ear. Findings indicate that bimodal benefit for temporally interrupted speech increases when continuity is restored to either or both ears. The primary benefit appears to stem from the continuous temporal envelope in the low-frequency region providing additional phonetic cues related to manner and F1 frequency; a secondary contribution is provided by low-frequency harmonicity cues when a continuous representation of the temporal envelope is present in the low-frequency, or both ears. The continuous temporal envelope and harmonicity cues of low-frequency speech are thought to support bimodal benefit by facilitating identification of word and syllable boundaries, and by restoring partial phonetic cues that occur during gaps in the temporally interrupted stimulus.

  19. Song Recognition by Young Children with Cochlear Implants: Comparison between Unilateral, Bilateral, and Bimodal Users

    ERIC Educational Resources Information Center

    Bartov, Tamar; Most, Tova

    2014-01-01

    Purpose: To examine song identification by preschoolers with normal hearing (NH) versus preschoolers with cochlear implants (CIs). Method: Participants included 45 children ages 3;8-7;3 (years;months): 12 with NH and 33 with CIs, including 10 with unilateral CI, 14 with bilateral CIs, and 9 bimodal users (CI-HA) with unilateral CI and…

  20. Effects of Removing Low-Frequency Electric Information on Speech Perception with Bimodal Hearing

    ERIC Educational Resources Information Center

    Fowler, Jennifer R.; Eggleston, Jessica L.; Reavis, Kelly M.; McMillan, Garnett P.; Reiss, Lina A. J.

    2016-01-01

    Purpose: The objective was to determine whether speech perception could be improved for bimodal listeners (those using a cochlear implant [CI] in one ear and hearing aid in the contralateral ear) by removing low-frequency information provided by the CI, thereby reducing acoustic-electric overlap. Method: Subjects were adult CI subjects with at…

  1. Perception of Consonants in Reverberation and Noise by Adults Fitted with Bimodal Devices

    ERIC Educational Resources Information Center

    Mason, Michelle; Kokkinakis, Kostas

    2014-01-01

    Purpose: The purpose of this study was to evaluate the contribution of a contralateral hearing aid to the perception of consonants, in terms of voicing, manner, and place-of-articulation cues in reverberation and noise by adult cochlear implantees aided by bimodal fittings. Method: Eight postlingually deafened adult cochlear implant (CI) listeners…

  2. An examination of bimodal nuclear power and propulsion benefits for outer solar system missions

    SciTech Connect

    Zubrin, R.; Mondt, J.

    1996-03-01

    This paper presents the results of an analysis of the capability of nuclear bimodal systems to perform outer solar system exploration missions. Missions of interest include orbiter missions to Jupiter, Saturn, Uranus, Neptune, and Pluto. An initial technology baseline consisting of the NEBA 10 kWe, 1000 N thrust, 850 s, 1500 kg bimodal system was selected, and its performance examined against a data base for trajectories to outer solar system planetary destinations to select optimal direct and gravity assisted trajectories for study. A conceptual design for a common bimodal spacecraft capable of performing missions to all the planetary destinations was developed and made the basis of end to end mission designs for orbiter missions to Jupiter, Saturn, and Neptune. All mission designs considered use the Atlas 2AS for launch. The radiological hazard associated with using Earth gravity assists on such missions was examined and shown to be small compared to that currently accepted on Earth fly-by missions involving RTGs. It is shown that the bimodal nuclear power and propulsion system offers many attractive options for planetary missions, including both conventional planetary missions in which all instruments are carried by a single primary orbiting spacecraft, and unconventional missions in which the primary spacecraft acts as a carrier, relay, and mother ship for a fleet of micro spacecraft deployed at the planetary destination. {copyright} {ital 1996 American Institute of Physics.}

  3. The Bi-Modal Organization: Balancing Autopoiesis and Fluid Social Networks for Sustainability

    ERIC Educational Resources Information Center

    Smith, Peter A. C.; Sharicz, Carol Ann

    2013-01-01

    Purpose: The purpose of this paper is to assist an organization to restructure as a bi-modal organization in order to achieve sustainability in today's highly complex business world. Design/methodology/approach: The paper is conceptual and is based on relevant literature and the authors' research and practice. Findings: Although fluid…

  4. Cross-Frequency Integration for Consonant and Vowel Identification in Bimodal Hearing

    ERIC Educational Resources Information Center

    Kong, Ying-Yee; Braida, Louis D.

    2011-01-01

    Purpose: Improved speech recognition in binaurally combined acoustic-electric stimulation (otherwise known as "bimodal hearing") could arise when listeners integrate speech cues from the acoustic and electric hearing. The aims of this study were (a) to identify speech cues extracted in electric hearing and residual acoustic hearing in the…

  5. Parallel Bimodal Bilingual Acquisition: A Hearing Child Mediated in a Deaf Family

    ERIC Educational Resources Information Center

    Cramér-Wolrath, Emelie

    2013-01-01

    The aim of this longitudinal case study was to describe bimodal and bilingual acquisition in a hearing child, Hugo, especially the role his Deaf family played in his linguistic education. Video observations of the family interactions were conducted from the time Hugo was 10 months of age until he was 40 months old. The family language was Swedish…

  6. An aryl-phosphonate appended macrocyclic platform for lanthanide based bimodal imaging agents.

    PubMed

    Placidi, Matteo P; Engelmann, Jörn; Natrajan, Louise S; Logothetis, Nikos K; Angelovski, Goran

    2011-11-07

    Four ligand systems have been prepared whose characteristics are well suited to the design of bimodal MRI and luminescence probes. The lanthanide complexes display high relaxivities and luminescence quantum yields. These properties are retained at higher magnetic fields and in a range of competitive environments including model extracellular medium and cultured cells.

  7. Bimodal Emotion Congruency Is Critical to Preverbal Infants' Abstract Rule Learning

    ERIC Educational Resources Information Center

    Tsui, Angeline Sin Mei; Ma, Yuen Ki; Ho, Anna; Chow, Hiu Mei; Tseng, Chia-huei

    2016-01-01

    Extracting general rules from specific examples is important, as we must face the same challenge displayed in various formats. Previous studies have found that bimodal presentation of grammar-like rules (e.g. ABA) enhanced 5-month-olds' capacity to acquire a rule that infants failed to learn when the rule was presented with visual presentation of…

  8. Effects of Removing Low-Frequency Electric Information on Speech Perception with Bimodal Hearing

    ERIC Educational Resources Information Center

    Fowler, Jennifer R.; Eggleston, Jessica L.; Reavis, Kelly M.; McMillan, Garnett P.; Reiss, Lina A. J.

    2016-01-01

    Purpose: The objective was to determine whether speech perception could be improved for bimodal listeners (those using a cochlear implant [CI] in one ear and hearing aid in the contralateral ear) by removing low-frequency information provided by the CI, thereby reducing acoustic-electric overlap. Method: Subjects were adult CI subjects with at…

  9. Perception of Consonants in Reverberation and Noise by Adults Fitted with Bimodal Devices

    ERIC Educational Resources Information Center

    Mason, Michelle; Kokkinakis, Kostas

    2014-01-01

    Purpose: The purpose of this study was to evaluate the contribution of a contralateral hearing aid to the perception of consonants, in terms of voicing, manner, and place-of-articulation cues in reverberation and noise by adult cochlear implantees aided by bimodal fittings. Method: Eight postlingually deafened adult cochlear implant (CI) listeners…

  10. Poly(acrylic acid) Bridged Gadolinium Metal-Organic Framework-Gold Nanoparticle Composites as Contrast Agents for Computed Tomography and Magnetic Resonance Bimodal Imaging

    PubMed Central

    Tian, Chixia; Zhu, Liping; Lin, Feng; Boyes, Stephen G.

    2015-01-01

    Imaging contrast agents for magnetic resonance imaging (MRI) and computed tomography (CT) have received significant attention in the development of techniques for early-stage cancer diagnosis. Gadolinium (Gd) (III), which has seven unpaired electrons and a large magnetic moment, can dramatically influence the water proton relaxation and hence exhibits excellent MRI contrast. On the other hand, gold (Au), which has a high atomic number and high x-ray attenuation coefficient, is an ideal contrast agent candidate for x-ray based CT imaging. Gd metal organic framework (MOF) nanoparticles with tunable size, high Gd (III) loading and multivalency can potentially overcome the limitations of clinically utilized Gd chelate contrast agents. In this work, we report for the first time the integration of GdMOF nanoparticles with gold nanoparticles (AuNPs) for the preparation of a MRI/CT bimodal imaging agent. Highly stable hybrid GdMOF/AuNPs composites have been prepared by using poly(acrylic acid) as a bridge between the GdMOF nanoparticles and AuNPs. The hybrid nanocomposites were then evaluated in MRI and CT imaging. The results revealed high longitudinal relaxivity in MRI and excellent CT imaging performance. Therefore, these GdMOF/AuNPs hybrid nanocomposites potentially provide a new platform for the development of multi-modal imaging probes. PMID:26147906

  11. Identifying and Representing Global Climates for Hydrology: Bimodal seasonal behaviour is rare

    NASA Astrophysics Data System (ADS)

    Knoben, Wouter; Woods, Ross; Freer, Jim

    2017-04-01

    How can we improve hydrologically relevant descriptions of climate? Climate variables precipitation (P), temperature (T), rainfall days (N) and potential evapotranspiration (E) are driving forces behind differences in global hydrology. It is possible to adequately summarize global climate variables with a simple sine curve for many locations, which makes it easier to compare climates between locations. Instead of monthly average P, T, N or E, three parameters in the sine curve approximate these monthly averages, with low loss of accuracy for most locations. This approach works best for locations where the seasonal pattern has one clear peak (unimodal, e.g. distinct wet and dry season in a monsoon climate) and adequately when the seasonal pattern is more or less constant (e.g. low annual variation such as temperatures in the tropics). In earlier research the sinusoidal functions used 12 months as the length of the seasonal cycle, giving one peak per calendar year. This approach is expected to be inadequate in parts of the tropics, where climates can follow bimodal, dual-peak, patterns. Expressing bimodal monthly climates with sine curves has so far not been systematically investigated. The ability to succinctly describe these bimodal climates and knowledge of where these climates occur can be helpful in better understanding global climate-hydrology interactions. We use the public CRU TS v3.23 data set (available at 0.5° latitude/longitude resolution) to derive sinusoidal functions that describe a typical year of monthly average P, T, N and E for all 0.5°x0.5° land cells. We derive these functions with a seasonal cycle length of both 12 (representative of unimodal climates) and 6 months (simulates bimodal climates). Two 6-month duration sine curves are used back-to-back to describe the full January to December year, assuming equal amplitudes for both peaks. The results show that the shorter length of the seasonal cycle improves the accuracy of our sinusoidal

  12. Predominant contribution of cis-regulatory divergence in the evolution of mouse alternative splicing

    PubMed Central

    Gao, Qingsong; Sun, Wei; Ballegeer, Marlies; Libert, Claude; Chen, Wei

    2015-01-01

    Divergence of alternative splicing represents one of the major driving forces to shape phenotypic diversity during evolution. However, the extent to which these divergences could be explained by the evolving cis-regulatory versus trans-acting factors remains unresolved. To globally investigate the relative contributions of the two factors for the first time in mammals, we measured splicing difference between C57BL/6J and SPRET/EiJ mouse strains and allele-specific splicing pattern in their F1 hybrid. Out of 11,818 alternative splicing events expressed in the cultured fibroblast cells, we identified 796 with significant difference between the parental strains. After integrating allele-specific data from F1 hybrid, we demonstrated that these events could be predominately attributed to cis-regulatory variants, including those residing at and beyond canonical splicing sites. Contrary to previous observations in Drosophila, such predominant contribution was consistently observed across different types of alternative splicing. Further analysis of liver tissues from the same mouse strains and reanalysis of published datasets on other strains showed similar trends, implying in general the predominant contribution of cis-regulatory changes in the evolution of mouse alternative splicing. PMID:26134616

  13. Skeletogenesis in sea urchin interordinal hybrid embryos.

    PubMed

    Brandhorst, B P; Davenport, R

    2001-07-01

    Reciprocal interordinal crosses were made between the sea urchins Strongylocentrotus purpuratus and Lytechinus pictus. Previous research indicated that the expression of many L. pictus genes is reduced in the hybrid embryos. The S. purpuratus gene encoding the spicule matrix protein SM50 and the L. pictus gene encoding its orthologue LSM34 were both expressed at normal levels per gene copy in hybrid embryos, and in about 32 skeletogenic primary mesenchyme cells (PMCs) in hybrid and natural gastrulae. In many embryos of all crosses, 16 PMCs initially ingressed, while 32-64 PMCs were present in gastrulae. The skeletal spicules of most hybrid plutei were predominantly like those of S. purpuratus, consistent with the predominance of expression of S. purpuratus genes in hybrid embryos. The spicules of some hybrid plutei showed features characteristic of L. pictus, such as recurrent rods, branched body rod tips, or convergent ventral transverse rods; a few hybrid spicules were predominantly like those of L. pictus. Based on our observations and the literature, we propose the following. Cues from the ectodermal epithelium position the PMCs as they elaborate the initial triradiate spicules. Their orientation and outgrowth appears to be responsible for the convergence of the tips of body rods in most S. purpuratus and hybrid embryos, unlike in most L. pictus embryos. Variations among hybrid and natural embryos in skeletal branching pattern reflect differences in interpretation by PMCs of patterning cues produced by the ectodermal epithelium that probably have similar spatial distributions in the two species.

  14. Resolving the age bimodality of galaxy stellar populations on kpc scales

    NASA Astrophysics Data System (ADS)

    Zibetti, Stefano; Gallazzi, Anna R.; Ascasibar, Y.; Charlot, S.; Galbany, L.; García Benito, R.; Kehrig, C.; de Lorenzo-Cáceres, A.; Lyubenova, M.; Marino, R. A.; Márquez, I.; Sánchez, S. F.; van de Ven, G.; Walcher, C. J.; Wisotzki, L.

    2017-01-01

    Galaxies in the local Universe are known to follow bimodal distributions in the global stellar populations properties. We analyze the distribution of the local average stellar-population ages of 654 053 sub-galactic regions resolved on ˜1-kpc scales in a volume-corrected sample of 394 galaxies, drawn from the CALIFA-DR3 integral-field-spectroscopy survey and complemented by SDSS imaging. We find a bimodal local-age distribution, with an old and a young peak primarily due to regions in early-type galaxies and star-forming regions of spirals, respectively. Within spiral galaxies, the older ages of bulges and inter-arm regions relative to spiral arms support an internal age bimodality. Although regions of higher stellar-mass surface-density, μ★, are typically older, μ★ alone does not determine the stellar population age and a bimodal distribution is found at any fixed μ★. We identify an "old ridge" of regions of age ˜9 Gyr, independent of μ★, and a "young sequence" of regions with age increasing with μ★ from 1-1.5 Gyr to 4-5 Gyr. We interpret the former as regions containing only old stars, and the latter as regions where the relative contamination of old stellar populations by young stars decreases as μ★ increases. The reason why this bimodal age distribution is not inconsistent with the unimodal shape of the cosmic-averaged star-formation history is that i) the dominating contribution by young stars biases the age low with respect to the average epoch of star formation, and ii) the use of a single average age per region is unable to represent the full time-extent of the star-formation history of "young-sequence" regions.

  15. Bimodal emotion congruency is critical to preverbal infants' abstract rule learning.

    PubMed

    Tsui, Angeline Sin Mei; Ma, Yuen Ki; Ho, Anna; Chow, Hiu Mei; Tseng, Chia-huei

    2016-05-01

    Extracting general rules from specific examples is important, as we must face the same challenge displayed in various formats. Previous studies have found that bimodal presentation of grammar-like rules (e.g. ABA) enhanced 5-month-olds' capacity to acquire a rule that infants failed to learn when the rule was presented with visual presentation of the shapes alone (circle-triangle-circle) or auditory presentation of the syllables (la-ba-la) alone. However, the mechanisms and constraints for this bimodal learning facilitation are still unknown. In this study, we used audio-visual relation congruency between bimodal stimulation to disentangle possible facilitation sources. We exposed 8- to 10-month-old infants to an AAB sequence consisting of visual faces with affective expressions and/or auditory voices conveying emotions. Our results showed that infants were able to distinguish the learned AAB rule from other novel rules under bimodal stimulation when the affects in audio and visual stimuli were congruently paired (Experiments 1A and 2A). Infants failed to acquire the same rule when audio-visual stimuli were incongruently matched (Experiment 2B) and when only the visual (Experiment 1B) or the audio (Experiment 1C) stimuli were presented. Our results highlight that bimodal facilitation in infant rule learning is not only dependent on better statistical probability and redundant sensory information, but also the relational congruency of audio-visual information. A video abstract of this article can be viewed at https://m.youtube.com/watch?v=KYTyjH1k9RQ. © 2015 John Wiley & Sons Ltd.

  16. Early Bimodal Stimulation Benefits Language Acquisition for Children with Cochlear Implants

    PubMed Central

    Moberly, Aaron C.; Lowenstein, Joanna H.; Nittrouer, Susan

    2015-01-01

    Hypothesis Adding a low-frequency acoustic signal to the cochlear implant (CI) signal (i.e., bimodal stimulation) for a period of time early in life improves language acquisition. Background Children must acquire sensitivity to the phonemic units of language to develop most language-related skills, including expressive vocabulary, working memory, and reading. Acquiring sensitivity to phonemic structure depends largely on having refined spectral (frequency) representations available in the signal, which does not happen with CIs alone. Combining the low-frequency acoustic signal available through hearing aids with the CI signal can enhance signal quality. A period with this bimodal stimulation has been shown to improve language skills in very young children. This study examined whether these benefits persist into childhood. Methods Data were examined for 48 children with CIs implanted under age 3 years, participating in a longitudinal study. All children wore hearing aids prior to receiving a CI, but upon receiving a first CI, 24 children had at least one year of bimodal stimulation (Bimodal group), and 24 children had only electric stimulation subsequent to implantation (CI-only group). Measures of phonemic awareness were obtained at second and fourth grade, along with measures of expressive vocabulary, working memory, and reading. Results Children in the Bimodal group generally performed better on measures of phonemic awareness, and that advantage was reflected in other language measures. Conclusions Having even a brief period of time early in life with combined electric-acoustic input provides benefits to language learning into childhood, likely due to the enhancement in spectral representations provided. PMID:26571408

  17. Resolving the age bimodality of galaxy stellar populations on kpc scales

    NASA Astrophysics Data System (ADS)

    Zibetti, Stefano; Gallazzi, Anna R.; Ascasibar, Y.; Charlot, S.; Galbany, L.; García Benito, R.; Kehrig, C.; de Lorenzo-Cáceres, A.; Lyubenova, M.; Marino, R. A.; Márquez, I.; Sánchez, S. F.; van de Ven, G.; Walcher, C. J.; Wisotzki, L.

    2017-06-01

    Galaxies in the local Universe are known to follow bimodal distributions in the global stellar population properties. We analyse the distribution of the local average stellar population ages of 654 053 sub-galactic regions resolved on ˜1 kpc scales in a volume-corrected sample of 394 galaxies, drawn from the Calar Alto Legacy Integral Field Area (CALIFA) DR3 integral-field-spectroscopy survey and complemented by Sloan Digital Sky Survey (SDSS) imaging. We find a bimodal local-age distribution, with an old and a young peak primarily due to regions in early-type galaxies and star-forming regions of spirals, respectively. Within spiral galaxies, the older ages of bulges and interarm regions relative to spiral arms support an internal age bimodality. Although regions of higher stellar mass surface density, μ*, are typically older, μ* alone does not determine the stellar population age and a bimodal distribution is found at any fixed μ*. We identify an 'old ridge' of regions of age ˜9 Gyr, independent of μ*, and a 'young sequence' of regions with age increasing with μ* from 1-1.5 to 4-5 Gyr. We interpret the former as regions containing only old stars, and the latter as regions where the relative contamination of old stellar populations by young stars decreases as μ* increases. The reason why this bimodal age distribution is not inconsistent with the unimodal shape of the cosmic-averaged star formation history is that (i) the dominating contribution by young stars biases the age low with respect to the average epoch of star formation, and (ii) the use of a single average age per region is unable to represent the full time extent of the star formation history of 'young sequence' regions.

  18. Differentiating the Use of Gaze in Bilingual-Bimodal Language Acquisition: A Comparison of Two Sets of Twins with Deaf Parents.

    ERIC Educational Resources Information Center

    Richmond-Welty, E. Daylene; Siple, Patricia

    1999-01-01

    Gaze during utterance was examined in a set of bilingual-bimodal twins acquiring spoken English and American Sign Language (ASL) and a set of monolingual twins acquiring ASL. The bilingual-bimodal twins differentiated their languages by age 3. Like the monolingual twins, the bilingual-bimodal twins established mutual gaze at the beginning of their…

  19. Differentiating the Use of Gaze in Bilingual-Bimodal Language Acquisition: A Comparison of Two Sets of Twins with Deaf Parents.

    ERIC Educational Resources Information Center

    Richmond-Welty, E. Daylene; Siple, Patricia

    1999-01-01

    Gaze during utterance was examined in a set of bilingual-bimodal twins acquiring spoken English and American Sign Language (ASL) and a set of monolingual twins acquiring ASL. The bilingual-bimodal twins differentiated their languages by age 3. Like the monolingual twins, the bilingual-bimodal twins established mutual gaze at the beginning of their…

  20. Kinetic approaches to lactose operon induction and bimodality.

    PubMed

    Michel, Denis

    2013-05-21

    The quasi-equilibrium approximation is acceptable when molecular interactions are fast enough compared to circuit dynamics, but is no longer allowed when cellular activities are governed by rare events. A typical example is the lactose operon (lac), one of the most famous paradigms of transcription regulation, for which several theories still coexist to describe its behaviors. The lac system is generally analyzed by using equilibrium constants, contradicting single-event hypotheses long suggested by Novick and Weiner (1957). Enzyme induction as an all-or-none phenomenon. Proc. Natl. Acad. Sci. USA 43, 553-566) and recently refined in the study of (Choi et al., 2008. A stochastic single-molecule event triggers phenotype switching of a bacterial cell. Science 322, 442-446). In the present report, a lac repressor (LacI)-mediated DNA immunoprecipitation experiment reveals that the natural LacI-lac DNA complex built in vivo is extremely tight and long-lived compared to the time scale of lac expression dynamics, which could functionally disconnect the abortive expression bursts and forbid using the standard modes of lac bistability. As alternatives, purely kinetic mechanisms are examined for their capacity to restrict induction through: (i) widely scattered derepression related to the arrival time variance of a predominantly backward asymmetric random walk and (ii) an induction threshold arising in a single window of derepression without recourse to nonlinear multimeric binding and Hill functions. Considering the complete disengagement of the lac repressor from the lac promoter as the probabilistic consequence of a transient stepwise mechanism, is sufficient to explain the sigmoidal lac responses as functions of time and of inducer concentration. This sigmoidal shape can be misleadingly interpreted as a phenomenon of equilibrium cooperativity classically used to explain bistability, but which has been reported to be weak in this system.

  1. Geographic variation in the structure of oak hybrid zones provides insights into the dynamics of speciation.

    PubMed

    Zeng, Yan-Fei; Liao, Wan-Jin; Petit, Rémy J; Zhang, Da-Yong

    2011-12-01

    Studying geographic variation in the rate of hybridization between closely related species could provide a useful window on the evolution of reproductive isolation. Reinforcement theory predicts greater prezygotic isolation in areas of prolonged contact between recently diverged species than in areas of recent contact, which implies that old contact zones would be dominated by parental phenotypes with few hybrids (bimodal hybrid zones), whereas recent contact zones would be characterized by hybrid swarms (unimodal hybrid zones). Here, we investigate how the hybrid zones of two closely related Chinese oaks, Quercus mongolica and Q. liaotungensis, are structured geographically using both nuclear and chloroplast markers. We found that populations of Q. liaotungensis located around the Changbai Mountains in Northeast China, an inferred glacial refugium, were introgressed by genes from Q. mongolica, suggesting historical contact between the two species in this region. However, these introgressed populations form sharp bimodal hybrid zones with Q. mongolica. In contrast, populations of Q. liaotungensis located in North China, which show no sign of ancient introgression with Q. mongolica, form unimodal hybrid zones with Q. mongolica. These results are consistent with the hypothesis that selection against hybrids has had sufficient time to reinforce the reproductive barriers between Q. liaotungensis and Q. mongolica in Northeast China but not in North China.

  2. Effect of aided hearing in the nonimplanted ear on bimodal hearing.

    PubMed

    Jang, Jeong Hun; Lee, Jun Ho; Chang, Sun O; Oh, Seung Ha

    2014-12-01

    This study was designed to evaluate the binaural effects from bimodal hearing according to the aided hearing threshold in the nonimplanted ear. Subjects included 17 individuals who continued to use a hearing aid (HA) in the nonimplanted ear for more than 6 months postoperatively. Speech perception and sound localization were tested with unilateral cochlear implantation (CI) and bimodal hearing with and without background noise. Materials were presented at an average of 70 dB sound pressure level from a front loudspeaker in a quiet condition and then with background noise at a signal-to-noise ratio of +10 dB HL. Speech perception scores were based on percent-correct performance of repeating a spoken word under each condition. Sound localization scores were obtained by averaging the sum of angle differences between the active loudspeaker and the loudspeaker indicated by the subject. Speech perception scores (mean ± SD) of unilateral CI and bimodal hearing were 63.3% ± 17.7% and 73.1% ± 18.5% under the quiet condition (p = 0.029) and 65.5% ± 21.9% and 70.9% ± 23.6% under the noisy condition (p = 0.01), respectively. Angle differences (mean ± SD) of unilateral CI and bimodal hearing were 72.8 ± 27.4 degrees and 84.1 ± 29.9 degrees under the quiet condition (p = 0.052) and 79.3 ± 26.9 degrees and 77.3 ± 22.0 degrees under the noisy condition (p = 0.906), respectively. Patients were divided into two groups according to their aided hearing thresholds: Group 1 (aided hearing threshold ≤50 dB HL; n = 8) and Group 2 (aided hearing threshold >50 dB HL; n = 9). The speech perception scores of bimodal hearing in each group were 85.3% ± 13.3% and 60.8% ± 17.5% (p = 0.023) under the quiet condition and 82.7% ± 9.0% and 59.4% ± 26.8% under the noisy condition (p = 0.052), respectively. For sound localization, the angle differences of bimodal hearing in each group were 54 ± 28.6 degrees and 83.9 ± 11.9 degrees under the quiet condition (p = 0.042) and 63.0 ± 23

  3. A subset of fat-predominant angiomyolipomas label for MDM2: a potential diagnostic pitfall.

    PubMed

    Asch-Kendrick, Rebecca J; Shetty, Shashi; Goldblum, John R; Sharma, Rajni; Epstein, Jonathan I; Argani, Pedram; Cimino-Mathews, Ashley

    2016-11-01

    Angiomyolipomas (AMLs) are typically benign mesenchymal tumors with variable histologic composition. Fat-predominant AMLs can mimic well-differentiated liposarcomas (WDLSs) both radiographically and histologically because of the abundance of fat with admixed atypical cells resembling lipoblasts. However, the treatment and prognosis of AMLs and WDLSs are vastly different. Immunohistochemistry for murine double minute 2 (MDM2) has been used to support a diagnosis of WDLS; however, MDM2 labeling has not been specifically evaluated in fat-predominant AMLs. Here, we evaluated MDM2 immunohistochemistry in 36 AMLs (including 14 conventional AMLs, 13 fat-predominant AMLs, 6 fat-rich AMLs, 3 epithelioid AMLs) and 10 WDLSs. In addition, we labeled cases for HMB45, calponin, or actin, which are immunostains traditionally used to label AML. We performed fluorescence in situ hybridization (FISH) for MDM2 amplification on selected cases. By immunohistochemistry, 14% (5/36) of AMLs were MDM2+, including 23% (3/13) of fat-predominant AMLs. All MDM2+ AMLs evaluated by FISH (n=4) were negative for MDM2 amplification. By immunohistochemistry, 90% of WDLSs were MDM2+, and both MDM2+ WDLSs evaluated by FISH (n=2) were MDM2 amplified. All 36 AMLs labeled with HMB45 and calponin or actin. No WDLS labeled with HMB45; however, 80% of WDLSs labeled with calponin or actin. Although uncommon, MDM2 labeling is seen in a subset of fat-predominant AMLs and is a potential diagnostic pitfall in the evaluation of fatty tumors of the retroperitoneum. HMB45 is more sensitive and specific for AML than calponin or actin, and an immunopanel containing both HMB45 and MDM2 may be warranted to distinguish between fat-predominant AML and WDLS in histologically ambiguous cases. Copyright © 2016 Elsevier Inc. All rights reserved.

  4. Fault current limiter-predominantly resistive behavior of a BSCCO shielded-core reactor

    SciTech Connect

    Ennis, M. G.; Tobin, T. J.; Cha, Y. S.; Hull, J. R.

    2000-06-30

    Tests were conducted to determine the electrical and magnetic characteristics of a superconductor shielded core reactor (SSCR). The results show that a closed-core SSCR is predominantly a resistive device and an open-core SSCR is a hybrid resistive/inductive device. The open-core SSCR appears to dissipate less than the closed-core SSCR. However, the impedance of the open-core SSCR is less than that of the closed-core SSCR. Magnetic and thermal diffusion are believed to be the mechanism that facilitates the penetration of the superconductor tube under fault conditions.

  5. Unimodal Versus Bimodal EEG-fMRI Neurofeedback of a Motor Imagery Task

    PubMed Central

    Perronnet, Lorraine; Lécuyer, Anatole; Mano, Marsel; Bannier, Elise; Lotte, Fabien; Clerc, Maureen; Barillot, Christian

    2017-01-01

    Neurofeedback is a promising tool for brain rehabilitation and peak performance training. Neurofeedback approaches usually rely on a single brain imaging modality such as EEG or fMRI. Combining these modalities for neurofeedback training could allow to provide richer information to the subject and could thus enable him/her to achieve faster and more specific self-regulation. Yet unimodal and multimodal neurofeedback have never been compared before. In the present work, we introduce a simultaneous EEG-fMRI experimental protocol in which participants performed a motor-imagery task in unimodal and bimodal NF conditions. With this protocol we were able to compare for the first time the effects of unimodal EEG-neurofeedback and fMRI-neurofeedback versus bimodal EEG-fMRI-neurofeedback by looking both at EEG and fMRI activations. We also propose a new feedback metaphor for bimodal EEG-fMRI-neurofeedback that integrates both EEG and fMRI signal in a single bi-dimensional feedback (a ball moving in 2D). Such a feedback is intended to relieve the cognitive load of the subject by presenting the bimodal neurofeedback task as a single regulation task instead of two. Additionally, this integrated feedback metaphor gives flexibility on defining a bimodal neurofeedback target. Participants were able to regulate activity in their motor regions in all NF conditions. Moreover, motor activations as revealed by offline fMRI analysis were stronger during EEG-fMRI-neurofeedback than during EEG-neurofeedback. This result suggests that EEG-fMRI-neurofeedback could be more specific or more engaging than EEG-neurofeedback. Our results also suggest that during EEG-fMRI-neurofeedback, participants tended to regulate more the modality that was harder to control. Taken together our results shed first light on the specific mechanisms of bimodal EEG-fMRI-neurofeedback and on its added-value as compared to unimodal EEG-neurofeedback and fMRI-neurofeedback. PMID:28473762

  6. Gene Expression in Leishmania Is Regulated Predominantly by Gene Dosage.

    PubMed

    Iantorno, Stefano A; Durrant, Caroline; Khan, Asis; Sanders, Mandy J; Beverley, Stephen M; Warren, Wesley C; Berriman, Matthew; Sacks, David L; Cotton, James A; Grigg, Michael E

    2017-09-12

    Leishmania tropica, a unicellular eukaryotic parasite present in North and East Africa, the Middle East, and the Indian subcontinent, has been linked to large outbreaks of cutaneous leishmaniasis in displaced populations in Iraq, Jordan, and Syria. Here, we report the genome sequence of this pathogen and 7,863 identified protein-coding genes, and we show that the majority of clinical isolates possess high levels of allelic diversity, genetic admixture, heterozygosity, and extensive aneuploidy. By utilizing paired genome-wide high-throughput DNA sequencing (DNA-seq) with RNA-seq, we found that gene dosage, at the level of individual genes or chromosomal "somy" (a general term covering disomy, trisomy, tetrasomy, etc.), accounted for greater than 85% of total gene expression variation in genes with a 2-fold or greater change in expression. High gene copy number variation (CNV) among membrane-bound transporters, a class of proteins previously implicated in drug resistance, was found for the most highly differentially expressed genes. Our results suggest that gene dosage is an adaptive trait that confers phenotypic plasticity among natural Leishmania populations by rapid down- or upregulation of transporter proteins to limit the effects of environmental stresses, such as drug selection.IMPORTANCELeishmania is a genus of unicellular eukaryotic parasites that is responsible for a spectrum of human diseases that range from cutaneous leishmaniasis (CL) and mucocutaneous leishmaniasis (MCL) to life-threatening visceral leishmaniasis (VL). Developmental and strain-specific gene expression is largely thought to be due to mRNA message stability or posttranscriptional regulatory networks for this species, whose genome is organized into polycistronic gene clusters in the absence of promoter-mediated regulation of transcription initiation of nuclear genes. Genetic hybridization has been demonstrated to yield dramatic structural genomic variation, but whether such changes in gene

  7. Abundance inhomogeneities and atmospheric structure in CN-bimodal globular cluster giants

    NASA Technical Reports Server (NTRS)

    Drake, Jeremy J.; Plez, Bertrand; Smith, Verne V.

    1993-01-01

    It has been suggested by several authors that the sodium and aluminum abundance variations correlating with CN-band strength, frequently observed in CN-bimodal globular cluster giants, could be spurious manifestations of different temperature structures in the 'CN-strong' and 'CN-weak' stars, caused by different molecular line blanketing related to the C, N, and O trio. For stellar parameters generally appropriate to giants in the intermediate metallicity CN-bimodal cluster M4, we demonstrate through new model atmosphere calculations, employing opacity sampling and spherical geometry, that the observed abundance anomalies cannot be the result of atmospheric temperature structure. Our results using spherical geometry are compared to identical calculations performed with plane-parallel geometry: the effects of atmospheric extension on derived abundances for all lines considered amount to less than 0.1 dex.

  8. Improving image contrast and material discrimination with nonlinear response in bimodal atomic force microscopy

    PubMed Central

    Forchheimer, Daniel; Forchheimer, Robert; Haviland, David B.

    2015-01-01

    Atomic force microscopy has recently been extented to bimodal operation, where increased image contrast is achieved through excitation and measurement of two cantilever eigenmodes. This enhanced material contrast is advantageous in analysis of complex heterogeneous materials with phase separation on the micro or nanometre scale. Here we show that much greater image contrast results from analysis of nonlinear response to the bimodal drive, at harmonics and mixing frequencies. The amplitude and phase of up to 17 frequencies are simultaneously measured in a single scan. Using a machine-learning algorithm we demonstrate almost threefold improvement in the ability to separate material components of a polymer blend when including this nonlinear response. Beyond the statistical analysis performed here, analysis of nonlinear response could be used to obtain quantitative material properties at high speeds and with enhanced resolution. PMID:25665933

  9. A long-term epigenetic memory switch controls bacterial virulence bimodality.

    PubMed

    Ronin, Irine; Katsowich, Naama; Rosenshine, Ilan; Balaban, Nathalie Q

    2017-02-07

    When pathogens enter the host, sensing of environmental cues activates the expression of virulence genes. Opposite transition of pathogens from activating to non-activating conditions is poorly understood. Interestingly, variability in the expression of virulence genes upon infection enhances colonization. In order to systematically detect the role of phenotypic variability in enteropathogenic E. coli (EPEC), an important human pathogen, both in virulence activating and non-activating conditions, we employed the ScanLag methodology. The analysis revealed a bimodal growth rate. Mathematical modeling combined with experimental analysis showed that this bimodality is mediated by a hysteretic memory-switch that results in the stable co-existence of non-virulent and hyper-virulent subpopulations, even after many generations of growth in non-activating conditions. We identified the per operon as the key component of the hysteretic switch. This unique hysteretic memory switch may result in persistent infection and enhanced host-to-host spreading.

  10. Analysis of the bi-modal nature of solar wind-magnetosphere coupling

    SciTech Connect

    Smith, J.P.; Horton, W.

    1997-05-01

    It has been shown that the optimal linear prediction filter relating the solar wind electric field and the geomagnetic activity, as measured by the AL index, is both bi-modal and dependent on the level of activity in the magnetosphere. Further studies truncated the prediction filter to a five parameter model containing two low-pass filtered delta functions of arbitrary amplitude and delay time. The present study elaborates on the nature of the bi-modal response by using the five parameter model to quantify the effects of the level of geomagnetic activity on each of the modes of the filter individually. The authors find that at all levels of activity, the second mode, occurring at approximately one hour, is relatively unchanged. The first mode, however, has a one parameter dependence on the level of activity in the magnetosphere. The amplitude of the first mode is shown to have a significant increase with respect to activity.

  11. Improving image contrast and material discrimination with nonlinear response in bimodal atomic force microscopy

    NASA Astrophysics Data System (ADS)

    Forchheimer, Daniel; Forchheimer, Robert; Haviland, David B.

    2015-02-01

    Atomic force microscopy has recently been extented to bimodal operation, where increased image contrast is achieved through excitation and measurement of two cantilever eigenmodes. This enhanced material contrast is advantageous in analysis of complex heterogeneous materials with phase separation on the micro or nanometre scale. Here we show that much greater image contrast results from analysis of nonlinear response to the bimodal drive, at harmonics and mixing frequencies. The amplitude and phase of up to 17 frequencies are simultaneously measured in a single scan. Using a machine-learning algorithm we demonstrate almost threefold improvement in the ability to separate material components of a polymer blend when including this nonlinear response. Beyond the statistical analysis performed here, analysis of nonlinear response could be used to obtain quantitative material properties at high speeds and with enhanced resolution.

  12. The Effect of Hydrolysis Temperature on Synthesis of Bimodally Nanostructured Porous Titania

    NASA Astrophysics Data System (ADS)

    Kim, Jinsoo; Chang Song, Ki; Pratsinis, Sotiris E.

    2000-12-01

    Bimodally porous (2-4 and 20-100 nm) titania powders were prepared by hydrolysis of titanium tetraisopropoxide (TTIP), and the effect of hydrolysis temperature on the phase transformation and pore structure was investigated. The phase transformation was slightly retarded with increasing hydrolysis temperature, when the initial water concentration was small. The evolution of particle phase composition from amorphous to crystalline anatase and rutile was largely proportional to the calcination temperature and the initial water concentration. The pore size distribution was bimodal with fine intra-particle pores (2-4 nm in diameter) and larger inter-particle pores (20-100 nm). The intra-particle pores decreased in diameter at the hydrolysis temperature of 20°C. The specific surface area (SSA) of the dried powders ranged from 253 to 587 m2/g and the highest SSA was obtained at the hydrolysis temperature of 20°C.

  13. Deaf parents of cochlear-implanted children: beliefs on bimodal bilingualism.

    PubMed

    Mitchiner, Julie Cantrell

    2015-01-01

    This study investigated 17 Deaf (1) families in North America with cochlear-implanted children about their attitudes, beliefs, and practices on bimodal bilingualism (defined as using both a visual/manual language and an aural/oral language) in American Sign Language (ASL) and English. A survey and follow-up interviews with 8 families were conducted. The majority of the Deaf families exhibited positive beliefs toward bimodal bilingualism, where they set high expectations for their children to become equally fluent in both languages. However, their perspectives about the purpose for each language differed; they viewed English as a "survival language" and ASL as a "cultural language" but supported the use of both languages at home as part of their children's lives. © The Author 2014. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

  14. Improving image contrast and material discrimination with nonlinear response in bimodal atomic force microscopy.

    PubMed

    Forchheimer, Daniel; Forchheimer, Robert; Haviland, David B

    2015-02-10

    Atomic force microscopy has recently been extented to bimodal operation, where increased image contrast is achieved through excitation and measurement of two cantilever eigenmodes. This enhanced material contrast is advantageous in analysis of complex heterogeneous materials with phase separation on the micro or nanometre scale. Here we show that much greater image contrast results from analysis of nonlinear response to the bimodal drive, at harmonics and mixing frequencies. The amplitude and phase of up to 17 frequencies are simultaneously measured in a single scan. Using a machine-learning algorithm we demonstrate almost threefold improvement in the ability to separate material components of a polymer blend when including this nonlinear response. Beyond the statistical analysis performed here, analysis of nonlinear response could be used to obtain quantitative material properties at high speeds and with enhanced resolution.

  15. Enhanced Electrocatalytic Activity of Pt/3D Hierarchical Bimodal Macroporous Carbon Nanospheres.

    PubMed

    Balgis, Ratna; Widiyastuti, W; Ogi, Takashi; Okuyama, Kikuo

    2017-07-19

    Proton exchange membrane fuel cells require electrocatalysts with a high platinum (Pt) loading, large active surface area, and favorable hydrodynamic profile for practical applications. Here, we report the design of three-dimensional hierarchical bimodal macroporous carbon nanospheres with an interconnected pore system, which are applied as an electrocatalyst support. Carbon-supported Pt (Pt/C) catalysts were prepared by aerosol spray pyrolysis followed by microwave chemical deposition. The hierarchical porous structures not only increased the dispersion of Pt nanoparticles but also improved catalytic performance. A hierarchical bimodal macroporous Pt/C catalyst with a mixture of 30 and 120 nm size pores showed the best performance. The electrochemical surface area and mass activity values of this support were 96 m(2) g(-1)-Pt and 378 mA mg(-1)-Pt, respectively at a Pt loading of 15 wt %.

  16. Synthesis and Characterization of Bimodal Nanoporous Cu Foams: Working Towards Inertial Fusion Energy

    SciTech Connect

    Cervantes, O; Hayes, J R; Hamza, A

    2007-09-28

    For the National Ignition Facility, at the Lawrence Livermore National Laboratory, nanoporous structures play a crucial role in the development of targets for high energy density experiments. Here we present a new bottom-up synthesis technique termed filter-casting for the creation of bimodal macro/nanoporous Cu structures. Homogeneous nanoporous monoliths can be synthesized using Cu nanoparticles and bimodal porosities can be achieved using sacrificial polystyrene spheres as a template. Control over the structure and composition is critical for target manufacturing. The measured densities of the Cu foam range between 1070-3390 mg/cm{sup 3}. Filter-casting is a powerful new method for directly synthesizing large nanoporous monoliths with predetermined composition, pore size, and pore structure.

  17. Bimodal score distributions and the Myers-Briggs Type Indicator: fact or artifact?

    PubMed

    Bess, Tammy L; Harvey, Robert J

    2002-02-01

    We examined Myers-Briggs Type Indicator (MBTI) score distributions computed using item response theory (IRT) to assess the generalizability of earlier bimodality reports that have been cited in support of the "type" versus "trait" view of personality. Using the BILOG IRT program to score a sample of approximately 12,000 individuals who participated in leadership development programs, theta score distributions for the 4 dimensions of the MBTI computed using 10 (the BILOG default) versus 50 quadrature points were compared. Results indicated that past reports of bimodality were artifacts caused by BILOG's default use of a small number of quadrature points; when larger numbers of points were used, score distributions became strongly center-weighted. Although our findings are not supportive of the "type"-based hypothesis, the extremely high correlations between theta scores (rs > .996) suggest that no practical differences would be expected as a function of the number-of-quadrature-points decision.

  18. Language co-activation and lexical selection in bimodal bilinguals: Evidence from picture–word interference*

    PubMed Central

    GIEZEN, MARCEL R.; EMMOREY, KAREN

    2015-01-01

    We used picture–word interference (PWI) to discover a) whether cross-language activation at the lexical level can yield phonological priming effects when languages do not share phonological representations, and b) whether semantic interference effects occur without articulatory competition. Bimodal bilinguals fluent in American Sign Language (ASL) and English named pictures in ASL while listening to distractor words that were 1) translation equivalents, 2) phonologically related to the target sign through translation, 3) semantically related, or 4) unrelated. Monolingual speakers named pictures in English. Production of ASL signs was facilitated by words that were phonologically related through translation and by translation equivalents, indicating that cross-language activation spreads from lexical to phonological levels for production. Semantic interference effects were not observed for bimodal bilinguals, providing some support for a post-lexical locus of semantic interference, but which we suggest may instead reflect time course differences in spoken and signed production in the PWI task. PMID:26989347

  19. Waveform simulation of predominant periods in Osaka basin

    NASA Astrophysics Data System (ADS)

    Petukhin, A.; Tsurugi, M.

    2016-12-01

    Predominant period of strong ground motions is an important parameter in earthquake engineering practice. Resonance at predominant period may result in collapse of building. Usually, predominant periods are associated with the soil resonances. However, considering that strong ground motions are composed from source, path and site effects, predominant periods are affected by source and propagation path too. From another side, 3D basin interferences may amplify quite different periods, depending on site location relatively to the basin edges and independently on the soil depth. Moreover, constructive or destructive interference of waves from different asperities of a large source may enhance or diminish amplitudes at a particular predominant period respectively. In this study, to demonstrate variations of predominant periods due to complicated effects above, we simulated wavefield snapshots and waveforms at a few representative sites of Osaka basin, Japan. Seismic source is located in Nankai trough, hosting anticipated M9 earthquake. 3D velocity structure is combined from JIVSM velocity structure (Koketsu et al., 2012) and Osaka basin structure of Iwaki and Iwata, 2011. 3D-FDM method is used to simulate waveforms. Simulation results confirm some previous results that due to elongated elliptical shape of Osaka basin, interference effects are strong and peak amplitudes has characteristic stripped pattern elongated in parallel to the long axis of basin. We demonstrate that predominant periods have similar pattern and value of predominant period may strongly depend on the location of site and azimuthal orientation of waveform component.

  20. The climatic imprint of bimodal distributions in vegetation cover for western Africa

    NASA Astrophysics Data System (ADS)

    Yin, Zun; Dekker, Stefan C.; van den Hurk, Bart J. J. M.; Dijkstra, Henk A.

    2016-06-01

    Observed bimodal distributions of woody cover in western Africa provide evidence that alternative ecosystem states may exist under the same precipitation regimes. In this study, we show that bimodality can also be observed in mean annual shortwave radiation and above-ground biomass, which might closely relate to woody cover due to vegetation-climate interactions. Thus we expect that use of radiation and above-ground biomass enables us to distinguish the two modes of woody cover. However, through conditional histogram analysis, we find that the bimodality of woody cover still can exist under conditions of low mean annual shortwave radiation and low above-ground biomass. It suggests that this specific condition might play a key role in critical transitions between the two modes, while under other conditions no bimodality was found. Based on a land cover map in which anthropogenic land use was removed, six climatic indicators that represent water, energy, climate seasonality and water-radiation coupling are analysed to investigate the coexistence of these indicators with specific land cover types. From this analysis we find that the mean annual precipitation is not sufficient to predict potential land cover change. Indicators of climate seasonality are strongly related to the observed land cover type. However, these indicators cannot predict a stable forest state under the observed climatic conditions, in contrast to observed forest states. A new indicator (the normalized difference of precipitation) successfully expresses the stability of the precipitation regime and can improve the prediction accuracy of forest states. Next we evaluate land cover predictions based on different combinations of climatic indicators. Regions with high potential of land cover transitions are revealed. The results suggest that the tropical forest in the Congo basin may be unstable and shows the possibility of decreasing significantly. An increase in the area covered by savanna and grass

  1. Disentangling the climate-driven bimodal growth pattern in coastal and continental Mediterranean pine stands.

    PubMed

    Pacheco, Arturo; Camarero, J Julio; Ribas, Montse; Gazol, Antonio; Gutierrez, E; Carrer, Marco

    2017-09-16

    Mediterranean climate promotes two distinct growth peaks separated by summer quiescence in trees. This bimodal pattern has been associated to favourable growing conditions during spring and autumn when mild temperatures and soil-water availability enhance cambial activity. Climatic models predict progressive warming and drying for the Mediterranean Basin, which could shorten or shift the spring and autumn growing seasons. We explored this idea by comparing two sites with different Mediterranean climate types (continental/dry and coastal/wet) and studied how climate drives the bimodal growth pattern in Aleppo pine (Pinus halepensis). Specifically we investigated the intra-annual changes in wood anatomy and the corresponding formation of density fluctuations (IADF). Trees on both sites were analyzed by dendrometer monitoring and by developing chronologies of wood anatomical traits. Radial-increment dynamics followed a similar bimodal pattern in both sites but coastal trees showed higher increments during the spring and autumn growth peaks, especially in autumn. The summer rest of cambium activity occurs almost one month earlier in the coastal than in the inland site. Lumen area and cell-wall thickness were significantly smaller in the continental site, while the increment rate of cell-wall thickness during an IADF event was much higher in the coastal pines. The accumulated soil moisture deficit was the main climatic constraint of tracheid enlargement in continental pines. Intra-annual density fluctuations were more frequent in the coastal trees where wood anatomy features recover to average values after such events, meanwhile inland trees presented a much lower recovery rate. Growth bimodality and the formation of density fluctuations were linked, but mild climate of the coastal site allows a longer growing season, which explains why trees in this area showed higher and more variable growth rates. Copyright © 2017. Published by Elsevier B.V.

  2. Simple power law for transport ratio with bimodal distributions of coarse sediments under waves

    NASA Astrophysics Data System (ADS)

    Calantoni, Joseph; Thaxton, Christopher S.

    2008-03-01

    Morphodynamic models of coastal evolution require relatively simple parameterizations of sediment transport for application over larger scales. Here we present a transport parameterization for bimodal distributions of coarse quartz grains using simulations from a discrete particle model for sheet flow and near sheet flow conditions. The discrete particle model simulates the simplest one-dimensional fluid using a turbulent eddy viscosity determined from a mixing length coupled to particle motions. The motions of individual sand grains are simulated using spherical elements. Newton's second law in translational and rotational forms is solved for every particle in the domain as determined by both grain-grain and grain-fluid interactions. The forcing from idealized monochromatic waves is accomplished by specifying a spatially constant, time varying horizontal pressure gradient acting on the simulation domain. Consequently, the time series of the free-stream fluid acceleration and velocity are also fixed. Simulations cover a range of wave forcing, diameter ratios for the large and small grains in the bimodal size distribution, and mass ratios of large to small grains in the simulation domain, for a total of 243 unique simulation conditions. The simulation results are successfully parameterized with a simple power law that allows for the prediction of the transport rates of each size fraction in the bimodal distribution. The simple power law determined from simulations provides favorable predictions of transport rates for each size fraction when applied to available laboratory data for sheet flow with bimodal size distributions. It is important to note that rapid vertical kinematic sorting of grains by size is explicitly simulated with the model and thus implicitly captured by the power law. Discussion focuses on practical application of the power law.

  3. Potential clinical applications of bimodal PET-MRI or SPECT-MRI agents†

    PubMed Central

    de Rosales, Rafael T M

    2014-01-01

    The introduction to the clinic of positron emission tomography-magnetic resonance imaging scanners opens up the possibility to evaluate the real potential of bimodal imaging agents. In this mini-review, the limitations in the design and applications of these materials are summarised and the unique properties that may result in real clinical applications outlined. © 2013 The Authors. Labelled Compounds and Radiopharmaceuticals published by John Wiley. PMID:24395384

  4. Flatfoot Diagnosis by a Unique Bimodal Distribution of Footprint Index in Children

    PubMed Central

    Chang, Chia-Hsieh; Chen, Yu-Chen; Yang, Wen-Tien; Ho, Pei-Chi; Hwang, Ai-Wen; Chen, Chien-Hung; Chang, Jia-Hao; Chang, Liang-Wey

    2014-01-01

    Background More than 1000 scientific papers have been devoted to flatfoot issue. However, a bimodal distribution of flatfoot indices in school-aged children has never been discovered. The purposes of this study were to establish a new classification of flatfoot by characteristic in frequency distribution of footprint index and to endue the classification with discrepancy in physical fitness. Methods/Principal Findings In a longitudinal survey of physical fitness and body structure, weight bearing footprints and 3 physical fitness related tests were measured in 1228 school-aged children. Frequency distribution of initial data was tested by Kolmogorov-Smirnov test for normality and a unique bimodal distribution of footprint index was identified. The frequency distribution of footprint index manifests two distinct modes, flatfoot and non-flatfoot, by deconvolution and bootstrapping procedures. A constant intersection value of 1.0 in Staheli's arch index and 0.6 in Chippaux-Smirak index could distinguish the two modes of children, and the value was constant in different age, sex, and weight status. The performance of the one leg balance was inferior in flatfoot girls (median, 4.0 seconds in flatfoot girls vs. 4.3 seconds in non-flatfoot girls, p = 0.04, 95% CI 0.404–0.484). Discussion The natural bimodality lends itself to a flatfoot classification. Bimodality suggests development of the child's foot arch would be a leap from one state to another, rather than a continuous growth as body height and weight. The underlying dynamics of the human foot arch and motor development will trigger research prospects. PMID:25551228

  5. Methodological Considerations about the Use of Bimodal Oddball P300 in Psychiatry: Topography and Reference Effect

    PubMed Central

    Schröder, Elisa; Kajosch, Hendrik; Verbanck, Paul; Kornreich, Charles; Campanella, Salvatore

    2016-01-01

    Event-related potentials (ERPs) bimodal oddball task has disclosed increased sensitivity to show P300 modulations to subclinical symptoms. Even if the utility of such a procedure has still to be confirmed at a clinical level, gathering normative values of this new oddball variant may be of the greatest interest. We specifically addressed the challenge of defining the best location for the recording of P3a and P3b components and selecting the best reference to use by investigating the effect of an offline re-reference procedure on recorded bimodal P3a and P3b. Forty young and healthy subjects were submitted to a bimodal (synchronized and always congruent visual and auditory stimuli) three-stimulus oddball task in which 140 frequent bimodal stimuli, 30 deviant “target” stimuli and 30 distractors were presented. Task consisted in clicking as soon as possible on the targets, and not paying attention to frequent stimuli and distractors. This procedure allowed us to record, for each individual, the P3a component, referring to the novelty process related to distractors processing, and the P3b component, linked to the processing of the target stimuli. Results showed that both P3a and P3b showed maximal amplitude in Pz. However, P3a displayed a more central distribution. Nose reference was also shown to give maximal amplitudes compared with average and linked mastoids references. These data were discussed in light of the necessity to develop multi-site recording guidelines to furnish sets of ERPs data comparable across laboratories. PMID:27708597

  6. Delamination and solvothermal decomposition of layered zinc hydroxysalt: Formation of bimodal zinc oxide nanostructures

    NASA Astrophysics Data System (ADS)

    Machado, Jyothi; Ravishankar, N.; Rajamathi, Michael

    2010-08-01

    Dodecylsulphate-intercalated zinc hydroxysalt, Zn 5(OH) 8(DS) 2·mH 2O delaminates to give monolayer colloidal dispersions in alcohols such as 1-butanol and ethylene glycol. The extent of delamination and the stability of the colloidal dispersion are comparable to those of layered double hydroxides. The solvothermal decomposition of the colloidal dispersion of the hydroxysalt in ethylene glycol yields a bimodal ZnO having a nanotubular structure decorated with nanosheets.

  7. Arctic low-level boundary layer clouds: in situ measurements and simulations of mono- and bimodal supercooled droplet size distributions at the top layer of liquid phase clouds

    NASA Astrophysics Data System (ADS)

    Klingebiel, M.; de Lozar, A.; Molleker, S.; Weigel, R.; Roth, A.; Schmidt, L.; Meyer, J.; Ehrlich, A.; Neuber, R.; Wendisch, M.; Borrmann, S.

    2015-01-01

    Aircraft borne optical in situ size distribution measurements were performed within Arctic boundary layer clouds with a special emphasis on the cloud top layer during the VERtical Distribution of Ice in Arctic clouds (VERDI) campaign in April and May 2012. An instrumented Basler BT-67 research aircraft operated out of Inuvik over the Mackenzie River delta and the Beaufort Sea in the Northwest Territories of Canada. Besides the cloud particle and hydrometeor size spectrometers the aircraft was equipped with instrumentation for aerosol, radiation and other parameters. Inside the cloud, droplet size distributions with monomodal shapes were observed for predominantly liquid-phase Arctic stratocumulus. With increasing altitude inside the cloud the droplet mean diameters grew from 10 to 20 μm. In the upper transition zone (i.e., adjacent to the cloud-free air aloft) changes from monomodal to bimodal droplet size distributions (Mode 1 with 20 μm and Mode 2 with 10 μm diameter) were observed. It is shown that droplets of both modes co-exist in the same (small) air volume and the bimodal shape of the measured size distributions cannot be explained as an observational artifact caused by accumulating data point populations from different air volumes. The formation of the second size mode can be explained by (a) entrainment and activation/condensation of fresh aerosol particles, or (b) by differential evaporation processes occurring with cloud droplets engulfed in different eddies. Activation of entrained particles seemed a viable possibility as a layer of dry Arctic enhanced background aerosol (which was detected directly above the stratus cloud) might form a second mode of small cloud droplets. However, theoretical considerations and model calculations (adopting direct numerical simulation, DNS) revealed that, instead, turbulent mixing and evaporation of larger droplets are the most likely reasons for the formation of the second droplet size mode in the uppermost region

  8. Arctic low-level boundary layer clouds: in-situ measurements and simulations of mono- and bimodal supercooled droplet size distributions at the cloud top layer

    NASA Astrophysics Data System (ADS)

    Klingebiel, M.; de Lozar, A.; Molleker, S.; Weigel, R.; Roth, A.; Schmidt, L.; Meyer, J.; Ehrlich, A.; Neuber, R.; Wendisch, M.; Borrmann, S.

    2014-06-01

    Aircraft borne optical in-situ size distribution measurements were performed within Arctic boundary layer clouds, with a special emphasis on the cloud top layer, during the VERtical Distribution of Ice in Arctic Clouds (VERDI) campaign. The observations were carried out within a joint research activity of seven German institutes to investigate Arctic boundary layer-, mixed-phase clouds in April and May 2012. An instrumented Basler BT-67 research aircraft operated out of Inuvik over the Mackenzie River delta and the Beaufort Sea in the Northwest Territories of Canada. Besides the cloud particle and hydrometeor size spectrometers the aircraft was equipped with instrumentation for aerosol, radiation and other parameters. Inside the cloud, droplet size distributions with monomodal shapes were observed for predominantly liquid-phase Arctic stratocumulus. With increasing altitude inside the cloud the droplet mean diameters grew from 10 μm to 20 μm. In the upper transition zone (i.e. adjacent to the cloud-free air aloft) changes from monomodal to bimodal droplet size distributions were observed. It is shown that droplets of both modes co-exist in the same (small) air volume and the bimodal shape of the measured size distributions cannot be explained as an observational artifact caused by accumulating two droplet populations from different air volumes. The formation of a second size mode can be explained by (a) entrainment and activation/condensation of fresh aerosol particles, or (b) by differential evaporation processes occurring with cloud droplets engulfed in different eddies. Activation of entrained particles seemed a viable possibility as a layer of dry Arctic enhanced background aerosol was detected directly above the stratus cloud might form a second mode of small cloud droplets. However, theoretical considerations and a model simulation revealed that, instead, turbulent mixing and evaporation of larger droplets most likely are the main reasons for the formation

  9. Correction: Stimuli-responsive magnetic nanoparticles for tumor-targeted bimodal imaging and photodynamic/hyperthermia combination therapy

    NASA Astrophysics Data System (ADS)

    Kim, Kyoung Sub; Kim, Jiyoung; Lee, Joo Young; Matsuda, Shofu; Hideshima, Sho; Mori, Yasurou; Osaka, Tetsuya; Na, Kun

    2016-06-01

    Correction for `Stimuli-responsive magnetic nanoparticles for tumor-targeted bimodal imaging and photodynamic/hyperthermia combination therapy' by Kyoung Sub Kim, et al., Nanoscale, 2016, DOI: 10.1039/c6nr02273a.

  10. Bimodal Density Distribution of Cryptodome Dacite from the 1980 Eruption of Mount St. Helens, Washington

    USGS Publications Warehouse

    Hoblitt, R.P.; Harmon, R.S.

    1993-01-01

    The explosion of a cryptodome at Mount St. Helens in 1980 produced two juvenile rock types that are derived from the same source magma. Their differences-color, texture and density-are due only to vesicularity differences. The vesicular gray dacite comprises bout 72% of the juvenile material; the black dacite comprises the other 28%. The density of juvenile dacite is bimodally distributed, with peaks at 1.6 g cm-3 (gray dacite) and 2.3 g cm-3 (black dacite). Water contents, deuterium abundances, and the relationship of petrographic structures to vapor-phase crystals indicate both rock types underwent pre-explosion subsurface vesiculation and degassing. The gray dacite underwent a second vesiculation event, probably during the 18 May explosion. In the subsurface, gases probably escaped through interconnected vesicles into the permeable volcanic edifice. We suggest that nonuniform degassing of an initially homogeneous magma produced volatile gradients in the cryptodome and that these gradients were responsible for the density bimodality. That is, water contents less than about 0.2-0.4 wt% produced vesicle growth rates that were slow in comparison to the pyroclast cooling rates; greater water contents produced vesicle growth rates that were fast in comparison to cooling rates. In this scheme, the dacite densities are bimodally distributed simply because, following decompression on 18 May 1980, one clast population vesiculated while the other did not. For clasts that did vesiculate, vesicle growth continued until it was arrested by fragmentation. ?? 1993 Springer-Verlag.

  11. Bimodal gold nanoparticle therapeutics for manipulating exogenous and endogenous protein levels in mammalian cells.

    PubMed

    Muroski, Megan E; Kogot, Joshua M; Strouse, Geoffrey F

    2012-12-05

    A new advance in cell transfection protocol using a bimodal nanoparticle agent to selectively manipulate protein expression levels within mammalian cells is demonstrated. The nanoparticle based transfection approach functions by controlled release of gene regulatory elements from a 6 nm AuNP (gold nanoparticle) surface. The endosomal release of the regulatory elements from the nanoparticle surface results in endogenous protein knockdown simultaneously with exogenous protein expression for the first 48 h. The use of fluorescent proteins as the endogenous and exogenous signals for protein expression enables the efficiency of codelivery of siRNA (small interfering RNA) for GFP (green fluorescent protein) knockdown and a dsRed-express linearized plasmid for induction to be optically analyzed in CRL-2794, a human kidney cell line expressing an unstable green fluorescent protein. Delivery of the bimodal nanoparticle in cationic liposomes results in 20% GFP knockdown within 24 h of delivery and continues exhibiting knockdown for up to 48 h for the bimodal agent. Simultaneous dsRed expression is observed to initiate within the same time frame with expression levels reaching 34% after 25 days although cells have divided approximately 20 times, implying daughter cell transfection has occurred. Fluorescence cell sorting results in a stable colony, as demonstrated by Western blot analysis. The simultaneous delivery of siRNA and linearized plasmid DNA on the surface of a single nanocrystal provides a unique method for definitive genetic control within a single cell and leads to a very efficient cell transfection protocol.

  12. Rheological and Solid-Liquid Separation Properties of Bimodal Suspensions of Colloidal Gibbsite and Boehmite

    PubMed

    Bruinsma; Wang; Li; Liu; Smith; Bunker

    1997-08-01

    Bimodal suspensions of nanometer-sized boehmite particles and micron-sized gibbsite particles in 0.10 M NaNO3 are used as models to gain insight into the physical properties of agglomerating colloidal suspensions containing bimodal distributions of primary particles. Results on the gibbsite-boehmite mixtures show that the presences of small particles in a suspension can have a dramatic impact on the rheological, sedimentation, and filtration characteristics of suspensions of larger particles. Transmission electron micrographs show that boehmite forms a coating on the larger gibbsite particles. The coating provides steric repulsion and reduces the attractive interactions between the larger particles, leading to viscosity decreases and greater densification of sediments and filter cakes. A model has been developed to rationalize observed property changes based on the range of agglomerate structures that can form in mixtures of large and small particles. Results are discussed in the content of the processing of nuclear waste sludges, but are applicable to a wide range of bimodal suspensions.

  13. Second language experience modulates functional brain network for the native language production in bimodal bilinguals.

    PubMed

    Zou, Lijuan; Abutalebi, Jubin; Zinszer, Benjamin; Yan, Xin; Shu, Hua; Peng, Danling; Ding, Guosheng

    2012-09-01

    The functional brain network of a bilingual's first language (L1) plays a crucial role in shaping that of his or her second language (L2). However, it is less clear how L2 acquisition changes the functional network of L1 processing in bilinguals. In this study, we demonstrate that in bimodal (Chinese spoken-sign) bilinguals, the functional network supporting L1 production (spoken language) has been reorganized to accommodate the network underlying L2 production (sign language). Using functional magnetic resonance imaging (fMRI) and a picture naming task, we find greater recruitment of the right supramarginal gyrus (RSMG), the right temporal gyrus (RSTG), and the right superior occipital gyrus (RSOG) for bilingual speakers versus monolingual speakers during L1 production. In addition, our second experiment reveals that these regions reflect either automatic activation of L2 (RSOG) or extra cognitive coordination (RSMG and RSTG) between both languages during L1 production. The functional connectivity between these regions, as well as between other regions that are L1- or L2-specific, is enhanced during L1 production in bimodal bilinguals as compared to their monolingual peers. These findings suggest that L1 production in bimodal bilinguals involves an interaction between L1 and L2, supporting the claim that learning a second language does, in fact, change the functional brain network of the first language.

  14. The distribution of ventilation during bronchoconstriction is patchy and bimodal: a PET imaging study.

    PubMed

    Venegas, Jose G; Schroeder, Tobias; Harris, Scott; Winkler, R Tilo; Melo, Marcos F Vidal

    2005-08-25

    Recent PET imaging data from bronchoconstricted sheep (Vidal Melo et al., 2005) showed that V /Q distributions were bimodal and topographically patchy, but including a substantial heterogeneity at scales <2.2 ml. In this paper, we reanalyze the experimental data to establish the contribution of ventilation (V (r)) heterogeneity to the bimodality in V /Q . This analysis demonstrates that the distribution of V (r) during bronchoconstriction was bimodal with large patches of severe hypoventilation occupying an average of 41% of the imaged lung. The degree of hypoventilation to these regions was highly correlated with the degree of oxygenation impairment, but was quite variable amongst animals in spite of consistent degrees of mechanical obstruction. Remarkably, those regions were found to be hyperventilated before methacholine and their degree of hyperventilation was correlated with their degree of hypoventilation during bronchoconstriction. These data suggest that improving the uniformity of ventilation at baseline may be a desirable therapeutic target if the risk of severe hypoxemia during asthma attacks is to be minimized and/or the distribution of inhaled pharmaceuticals is to be optimized.

  15. Rarefaction effects in dilute granular Poiseuille flow: Knudsen minimum and temperature bimodality

    NASA Astrophysics Data System (ADS)

    Mahajan, Achal; Alam, Meheboob

    2015-11-01

    The gravity-driven flow of smooth inelastic hard-disks through a channel, analog of granular Poiseuille flow, is analysed using event-driven simulations. We find that the variation of the mass-flow rate (Q) with Knudsen number (Kn) can be non-monotonic in the elastic limit (i.e. the restitution coefficient en --> 1) in channels with very smooth walls. The Knudsen minimum effect (i.e. the minimum flow rate occurring at Kn ~ O (1) for the Poiseuille flow of a molecular gas) is found to be absent in a granular gas with en <= 0 . 99 , irrespective of wall roughness. Another rarefaction phenomenon, the bimodality of the temperature profile, with a local minimum at the channel centerline and two symmetric maxima (Tmax) away from the centerline, is studied. We show that the inelastic dissipation is responsible for the onset of temperature bimodality [i.e. the excess temperature, ▵ T = (Tmax /Tmin - 1) ≠ 0 ] near the continuum limit (Kn ~ 0), but the rarefaction being its origin (as in molecular gas) holds beyond Kn ~ O (0 . 1) . The competition between dissipation and rarefaction seems to be responsible for the observed dependence of both mass-flow rate and temperature bimodality on Kn and en . [Alam etal. 2015, JFM (revised)].

  16. Die Bonding Performance Using Bimodal Cu Particle Paste Under Different Sintering Atmospheres

    NASA Astrophysics Data System (ADS)

    Gao, Yue; Zhang, Hao; Li, Wanli; Jiu, Jinting; Nagao, Shijo; Sugahara, Tohru; Suganuma, Katsuaki

    2017-07-01

    A one-step polyol method was employed to synthesize bimodal Cu particles with average diameters around 200 nm and 1000 nm, respectively. The bimodal Cu particles were mixed with a reductive solvent of polyethylene glycol (PEG) to form a paste. The Cu paste was used as die bonding material to prepare Cu joints under N2 or vacuum sintering atmosphere. The results showed that the strength of the Cu joints in N2 atmosphere was always higher than that in vacuum. The shear strength of a Cu joint processed at 350°C under only 0.4 MPa bonding pressure in N2 was above 40 MPa, which was far higher than that obtained using single-sized nano-Cu particle paste. It is related to the dense packing of the bimodal Cu particles and slow decomposition behavior of the reductive PEG solvent. The reductive PEG solvent in the Cu paste, which effectively removed oxides on the surface of the Cu particles, was necessary for easy-oxidized Cu pastes. These results suggested that Cu pastes with suitable particle sizes, reducing solvent and sintering atmosphere could be a proper candidate for low-temperature and low-pressure bonding process.

  17. Cross-frequency Integration for Consonant and Vowel Identification in Bimodal Hearing

    PubMed Central

    Kong, Ying-Yee; Braida, Louis D.

    2011-01-01

    Purpose Improved speech recognition in binaurally combined acoustic-electric stimulation (“bimodal hearing”) could arise when listeners integrate speech cues from the acoustic and electric hearing. The aims of this study are (1) to identify speech cues extracted in electric hearing and residual acoustic hearing in the low-frequency region and (2) to investigate cochlear-implant (CI) users' ability to integrate speech cues across frequencies. Method Normal-hearing (NH) and CI subjects participated in consonant and vowel identification tasks. Each subject was tested in three listening conditions: CI alone (vocoder speech for NH), hearing aid (HA) alone (low-passed speech for NH), and both. Integration ability for each subject was evaluated using a model of optimal integration – PreLabeling Integration model [L.D. Braida, Q. J. Exp. Psychol. A 43,647-677 (1991)]. Results Only a few CI listeners demonstrated bimodal benefit for phoneme identification in quiet. Speech cues extracted from the CI and the HA are highly redundant for consonants, but complementary for vowels. CI listeners also exhibited reduced integration ability for both consonant and vowel identification compared to their NH counterparts. Conclusion These findings suggest that reduced bimodal benefits in CI listeners are due to insufficient complementary speech cues across ears, a decrease in integration ability, or both. PMID:21060139

  18. Phonological Skills in Predominantly English-Speaking, Predominantly Spanish-Speaking, and Spanish-English Bilingual Children

    ERIC Educational Resources Information Center

    Goldstein, Brian A.; Fabiano, Leah; Washington, Patricia Swasey

    2005-01-01

    Purpose: There is a paucity of information detailing the phonological skills of Spanish-English bilingual children and comparing that information to information concerning the phonological skills of predominantly English-speaking (PE) and predominantly Spanish-speaking (PS) children. The purpose of this study was to examine the relationship…

  19. Predominant mania course in Indian patients with bipolar I disorder.

    PubMed

    Rangappa, Sushma Bilichodu; Munivenkatappa, Shashidhara; Narayanaswamy, Janardhanan C; Jain, Sanjeev; Reddy, Y C Janardhan

    2016-08-01

    Many long-term follow-up studies suggest that bipolar disorder (BD) is highly recurrent and that depressive episodes are commoner than hypomania/manic episodes. However, some studies from tropical countries including India suggest that the patients experience a greater proportion of manic episodes than depressive episodes. The aim of the present study was to examine the course of BD type 1 (BD I) in a sample of hospitalized Indian subjects. We examined the clinical course of 285 BD I subjects with at least 5 years of illness using standard life charting method. These subjects were hospitalized between October 2010 and October 2012. The predominant polarity (having at least two-thirds of their lifetime episodes at one polarity) was mania (79%). Unipolar mania (≥ 3 mania episodes and no episodes of depression) was observed in 48% of the subjects. The frequency of rapid cycling course was noted in 2.5% of the subjects. Predominant manic polarity group had the illness onset mostly with a manic episode (88.9%) and the predominant depressive polarity group with a depressive episode (73.8%). Mania was the predominant polarity with a high rate of unipolar mania and a majority of the subjects had greater number of manic episodes than depressive/mixed episodes. The onset polarity determined the predominant polarity during the course of illness. Predominantly, mania course could have significant implications in the treatment of bipolar disorder.

  20. Early Cretaceous bimodal volcanism in the Duolong Cu mining district, western Tibet: Record of slab breakoff that triggered ca. 108-113 Ma magmatism in the western Qiangtang terrane

    NASA Astrophysics Data System (ADS)

    Wei, Shao-gang; Tang, Ju-xing; Song, Yang; Liu, Zhi-bo; Feng, Jun; Li, Yan-bo

    2017-05-01

    We report new zircon U-Pb ages and Hf isotope compositions, and whole-rock major and trace element and Sr-Nd isotope data for the Meiriqiecuo Formation (MF) bimodal volcanic rocks collected from the Duolong Cu mining district (DCMD) in the western Qiangtang terrane (QT), western Tibet. These data provide important constraints on the petrogenetic evolution and geodynamic setting of Early Cretaceous magmatism in the DCMD. The MF bimodal volcanic rocks are mainly basaltic andesite and andesite, with subordinate rhyolite. Four mafic samples yielded zircon U-Pb ages of ca. 108.2-113.0 Ma, and one silicic sample has an age of 109.3 ± 2.2 Ma, indicating that the mafic and silicic eruptions were contemporaneous. The MF bimodal volcanic rocks belong to the medium-K calc-alkaline to shoshonite series. The rocks show arc-type affinities characterized by significant enrichment in light rare earth (LaN/YbN = 7.74-12.60) and large-ion lithophile elements (Rb, Cs, K, and Pb), but depletions in the high-field-strength elements (Nb, Ta, and Ti), which geochemically resemble Andean arc basalts. Therefore, the MF bimodal volcanic rocks were likely emplaced at an Andean-type active continental margin and represent an Early Cretaceous magmatic arc that was located at the western QT margin. Moreover, the mafic volcanic rocks have high initial Sr isotopic ratios (0.705269-0.705413) and negative εNd(t) values of -1.5 to -0.6 compared with the silicic volcanic rocks ((87Sr/86Sr)i = 0.704770-0.704903; εNd(t) = +1.2 to +1.3). Zircons from silicic samples have significantly higher εHf(t) values (+11.6 to +15.5) and predominantly lower Paleoproterozoic Hf crustal model ages (TDMC = 180-428 Ma) than the mafic samples, which have variable εHf(t) values of +3.4 to +13.0 and TDMC ages of 346-952 Ma. These results indicate that the mafic and silicic end-members of the MF bimodal suite were generated from mantle and crustal sources, respectively. The basaltic andesite and andesite may have been

  1. Hybrid Vehicles

    DTIC Science & Technology

    2008-12-08

    hybrid electric vehicles typically contain potentially hazardous levels of electrical voltage or current. It is important to protect the operators...60740. ITOP 2-2-607(1)41 is used for tracked vehicles. 13 TOP 2-1-003 08 December 2008 Hybrid electric vehicles often employ much more

  2. Assortative preferences and discrimination by females against hybrid male song in the grasshoppers Chorthippus brunneus and Chorthippus jacobsi (Orthoptera: Acrididae).

    PubMed

    Bridle, J R; Saldamando, C I; Koning, W; Butlin, R K

    2006-07-01

    The grasshoppers Chorthippus brunneus and Chorthippus jacobsi are highly differentiated for male mating signals, and form a mosaic hybrid zone in northern Spain. At some sites within this zone, many hybrids are observed. At others, few hybrids are observed. Such bimodal sites may reflect recent contacts between parental genotypes, or local variation in levels of assortative mating or selection against hybrids. Playback of 12 parental and F1 male songs to 296 parental and hybrid females revealed positive assortative preferences in C. brunneus and C. jacobsi females, supporting a direct role of male mating signals in female choice. However, all female genotypic classes showed reduced responsiveness to F1 male songs. Such sexual selection against hybrids is consistent with the narrow cline width observed in the field for song characters relative to morphology. These results have implications for the genetic structure of the hybrid zone and for models of speciation by reinforcement.

  3. Bimodal bilingualism*

    PubMed Central

    EMMOREY, KAREN; BORINSTEIN, HELSA B.; THOMPSON, ROBIN; GOLLAN, TAMAR H.

    2008-01-01

    Speech–sign or “bimodal” bilingualism is exceptional because distinct modalities allow for simultaneous production of two languages. We investigated the ramifications of this phenomenon for models of language production by eliciting language mixing from eleven hearing native users of American Sign Language (ASL) and English. Instead of switching between languages, bilinguals frequently produced code-blends (simultaneously produced English words and ASL signs). Code-blends resembled co-speech gesture with respect to synchronous vocal–manual timing and semantic equivalence. When ASL was the Matrix Language, no single-word code-blends were observed, suggesting stronger inhibition of English than ASL for these proficient bilinguals. We propose a model that accounts for similarities between co-speech gesture and code-blending and assumes interactions between ASL and English Formulators. The findings constrain language production models by demonstrating the possibility of simultaneously selecting two lexical representations (but not two propositions) for linguistic expression and by suggesting that lexical suppression is computationally more costly than lexical selection. PMID:19079743

  4. The geochemistry and petrogenesis of the Paleoproterozoic Green Mountain arc: A composite(?), bimodal, oceanic, fringing arc

    USGS Publications Warehouse

    Jones, D.S.; Barnes, C.G.; Premo, W.R.; Snoke, A.W.

    2011-01-01

    The inferred subduction affinity of the ~1780-Ma Green Mountain arc, a dominantly bimodal igneous terrane (together with immature marine and volcaniclastic sedimentary rocks) accreted to the southern margin of the Wyoming province, is integral to arc-accretion models of the Paleoproterozoic growth of southern Laurentia. Conversely, the dominantly bimodal nature of many putative arc-related igneous suites throughout southern Laurentia, including the Green Mountain arc, has also been used to support models of growth by extension of pre-existing crust. We report new geochemical and isotopic data from ~1780-Ma gabbroic and granodioritic to tonalitic rocks of the Big Creek Gneiss, interpreted as consanguineous with previously studied metavolcanic rocks of the Green Mountain Formation.The ~1780-Ma Big Creek Gneiss mafic rocks show clear geochemical signatures of a subduction origin and provide no supporting evidence for extensional tectonism. The ~1780-Ma Big Creek Gneiss felsic rocks are attributed to partial melting of mafic and/or mixed lower-crustal material. The bimodal nature of the suite results from the combination of arc basalts and felsic crustal melts. The lack of andesite is consistent with the observed tholeiitic differentiation trend of the mafic magmas. The lower e{open}Nd(1780Ma) values for the felsic rocks vs. the mafic rocks suggest that the unexposed lower crust of the arc may be older than the arc and that Trans-Hudson- or Penokean-aged rocks possibly form the substratum of the arc. Our results reinforce previous interpretations that arc-related magmatism played a key role in the Paleoproterozoic crustal growth of southern Laurentia, but also support the possibility of unexposed older crust as basement to the arcs. ?? 2011 Elsevier B.V.

  5. Acid-base and ion balance in fishes with bimodal respiration.

    PubMed

    Shartau, R B; Brauner, C J

    2014-03-01

    The evolution of air breathing during the Devonian provided early fishes with bimodal respiration with a stable O2 supply from air. This was, however, probably associated with challenges and trade-offs in terms of acid-base balance and ionoregulation due to reduced gill:water interaction and changes in gill morphology associated with air breathing. While many aspects of acid-base and ionoregulation in air-breathing fishes are similar to water breathers, the specific cellular and molecular mechanisms involved remain largely unstudied. In general, reduced ionic permeability appears to be an important adaptation in the few bimodal fishes investigated but it is not known if this is a general characteristic. The kidney appears to play an important role in minimizing ion loss to the freshwater environment in the few species investigated, and while ion uptake across the gut is probably important, it has been largely unexplored. In general, air breathing in facultative air-breathing fishes is associated with an acid-base disturbance, resulting in an increased partial pressure of arterial CO2 and a reduction in extracellular pH (pHE ); however, several fishes appear to be capable of tightly regulating tissue intracellular pH (pHI ), despite a large sustained reduction in pHE , a trait termed preferential pHI regulation. Further studies are needed to determine whether preferential pHI regulation is a general trait among bimodal fishes and if this confers reduced sensitivity to acid-base disturbances, including those induced by hypercarbia, exhaustive exercise and hypoxia or anoxia. Additionally, elucidating the cellular and molecular mechanisms may yield insight into whether preferential pHI regulation is a trait ultimately associated with the early evolution of air breathing in vertebrates.

  6. Bimodal in vivo imaging provides early assessment of stem-cell-based photoreceptor engraftment

    PubMed Central

    Laver, C R J; Metcalfe, A L; Szczygiel, L; Yanai, A; Sarunic, M V; Gregory-Evans, K

    2015-01-01

    Purpose Subretinal transplantation of stem-cell-derived photoreceptor precursor cells (PPCs) is a promising and innovative approach to treating a range of blinding diseases. However, common barriers to efficient preclinical transplantation comes in the form of suboptimal graft architecture, limited graft survival, and immune-rejection, each of which cannot be assessed using conventional in vivo imaging (ie, rodent ophthalmoscopy). With the majority of PPCs reported to die within the first few weeks after transplantation, understanding the mechanisms of graft failure, and ultimately devising preventative methods, currently relies on lengthy end point histology. To address these limitations, we hypothesized that combining two imaging modalities, optical coherence tomography (OCT) and fluorescence confocal scanning laser ophthalmoscopy (fcSLO), could provide a more rapid and comprehensive view of PPC engraftment. Methods Human ESC-derived PPCs were transplanted into 15 retinal dystrophic rats that underwent bimodal imaging at 0, 8, and 15 days posttransplant. Results Bimodal imaging provided serial detection of graft: placement, architecture, and survival; each undetectable under ophthalmoscopy. Bimodal imaging determined graft placement to be either: subretinal (n=7), choroidal (n=4), or vitreal (n=4) indicating neural retinal perforation. Graft architecture was highly variable at the time of transplantation, with notable redistribution over time, while complete, or near complete, graft loss was observed in the majority of recipients after day 8. Of particular importance was detection of vitreal aggregates overlying the graft—possibly an indicator of host-site inflammation and rejection. Conclusion Early real-time feedback of engraftment has the potential to greatly increase efficiency of preclinical trials in cell-based retinal therapeutics. PMID:25771816

  7. Dynamic imaging of lymphatic vessels and lymph nodes using a bimodal nanoparticulate contrast agent.

    PubMed

    Mounzer, Rawad; Shkarin, Pavel; Papademetris, Xenophon; Constable, Todd; Ruddle, Nancy H; Fahmy, Tarek M

    2007-01-01

    Evaluation of lymphedema and lymph node metastasis in humans has relied primarily on invasive or radioactive modalities. While noninvasive technologies such as magnetic resonance imaging (MRI) offer the potential for true three-dimensional imaging of lymphatic structures, invasive modalities, such as optical fluorescence microscopy, provide higher resolution and clearer delineation of both lymph nodes and lymphatic vessels. Thus, contrast agents that image lymphatic vessels and lymph nodes by both fluorescence and MRI may further enhance our understanding of the structure and function of the lymphatic system. Recent applications of bimodal (fluorescence and MR) contrast agents in mice have not achieved clear visualization of lymphatic vessels and nodes. Here the authors describe the development of a nanoparticulate contrast agent that is taken up by lymphatic vessels to draining lymph nodes and detected by both modalities. A unique nanoparticulate contrast agent composed of a polyamidoamine dendrimer core conjugated to paramagnetic contrast agents and fluorescent probes was synthesized. Anesthetized mice were injected with the nanoparticulates in the hind footpads and imaged by MR and fluorescence microscopy. High resolution MR and fluorescence images were obtained and compared to traditional techniques for lymphatic visualization using Evans blue dye. Lymph nodes and lymphatic vessels were clearly observed by both MRI and fluorescence microscopy using the bimodal nanoparticulate contrast agent. Characteristic tail-lymphatics were also visualized by both modalities. Contrast imaging yielded a higher resolution than the traditional method employing Evans blue dye. MR data correlated with fluorescence and Evans blue dye imaging. A bimodal nanoparticulate contrast agent facilitates the visualization of lymphatic vessels and lymph nodes by both fluorescence microscopy and MRI with strong correlation between the two modalities. This agent may translate to applications

  8. 'Bimodal' NTR and LANTR propulsion for human missions to Mars/Phobos

    SciTech Connect

    Borowski, Stanley K.; Dudzinski, Leonard A.; McGuire, Melissa L.

    1999-01-22

    The nuclear thermal rocket (NTR) is one of the leading propulsion options for future human missions to Mars due to its high specific impulse (Isp {approx}850-1000 s) and attractive engine thrust-to-weight ratio ({approx}3-10). Because only a miniscule amount of enriched uranium-235 fuel is consumed in a NTR during the primary propulsion maneuvers of a typical Mars mission, engines configured for both propulsive thrust and modest power generation (referred to as 'bimodal' operation) provide the basis for a robust, 'power-rich' stage enabling propulsive Mars capture and reuse capability. A family of modular 'bimodal' NTR (BNTR) vehicles are described which utilize a common 'core' stage powered by three 66.7 kN ({approx}15 klbf) BNTRs that produce 50 kWe of total electrical power for crew life support, an active refrigeration/reliquification system for long term, 'zero-boiloff' liquid hydrogen (LH{sub 2}) storage, and high data rate communications. Compared to other propulsion options, a Mars mission architecture using BNTR transfer vehicles requires fewer transportation system elements which reduces mission mass, cost and risk because of simplified space operations. For difficult Mars options, such as a Phobos rendezvous and sample return mission, volume (not mass) constraints limit the performance of the 'all LH{sub 2}' BNTR stage. The use of 'LOX-augmented' NTR (LANTR) engines, operating at a modest oxygen-to-hydrogen (O/H) mixture ratio (MR) of 0.5, helps to increase 'bulk' propellant density and total thrust during the trans-Mars injection (TMI) burn. On all subsequent burns, the bimodal LANTR engines operate on LH{sub 2} only (MR=0) to maximize vehicle performance while staying within the mass limits of two {approx}80 t 'Magnum' heavy lift launch vehicles (HLLVs)

  9. Oncogenic Nras has bimodal effects on stem cells that sustainably increase competitiveness.

    PubMed

    Li, Qing; Bohin, Natacha; Wen, Tiffany; Ng, Victor; Magee, Jeffrey; Chen, Shann-Ching; Shannon, Kevin; Morrison, Sean J

    2013-12-05

    'Pre-leukaemic' mutations are thought to promote clonal expansion of haematopoietic stem cells (HSCs) by increasing self-renewal and competitiveness; however, mutations that increase HSC proliferation tend to reduce competitiveness and self-renewal potential, raising the question of how a mutant HSC can sustainably outcompete wild-type HSCs. Activating mutations in NRAS are prevalent in human myeloproliferative neoplasms and leukaemia. Here we show that a single allele of oncogenic Nras(G12D) increases HSC proliferation but also increases reconstituting and self-renewal potential upon serial transplantation in irradiated mice, all prior to leukaemia initiation. Nras(G12D) also confers long-term self-renewal potential to multipotent progenitors. To explore the mechanism by which Nras(G12D) promotes HSC proliferation and self-renewal, we assessed cell-cycle kinetics using H2B-GFP label retention and 5-bromodeoxyuridine (BrdU) incorporation. Nras(G12D) had a bimodal effect on HSCs, increasing the frequency with which some HSCs divide and reducing the frequency with which others divide. This mirrored bimodal effects on reconstituting potential, as rarely dividing Nras(G12D) HSCs outcompeted wild-type HSCs, whereas frequently dividing Nras(G12D) HSCs did not. Nras(G12D) caused these effects by promoting STAT5 signalling, inducing different transcriptional responses in different subsets of HSCs. One signal can therefore increase HSC proliferation, competitiveness and self-renewal through bimodal effects on HSC gene expression, cycling and reconstituting potential.

  10. Effect of extreme adaptive frequency compression in bimodal listeners on sound localization and speech perception.

    PubMed

    Veugen, Lidwien C E; Chalupper, Josef; Mens, Lucas H M; Snik, Ad F M; van Opstal, A John

    2017-09-01

    This study aimed to improve access to high-frequency interaural level differences (ILD), by applying extreme frequency compression (FC) in the hearing aid (HA) of 13 bimodal listeners, using a cochlear implant (CI) and conventional HA in opposite ears. An experimental signal-adaptive frequency-lowering algorithm was tested, compressing frequencies above 160 Hz into the individual audible range of residual hearing, but only for consonants (adaptive FC), thus protecting vowel formants, with the aim to preserve speech perception. In a cross-over design with at least 5 weeks of acclimatization between sessions, bimodal performance with and without adaptive FC was compared for horizontal sound localization, speech understanding in quiet and in noise, and vowel, consonant and voice-pitch perception. On average, adaptive FC did not significantly affect any of the test results. Yet, two subjects who were fitted with a relatively weak frequency compression ratio, showed improved horizontal sound localization. After the study, four subjects preferred adaptive FC, four preferred standard frequency mapping, and four had no preference. Noteworthy, the subjects preferring adaptive FC were those with best performance on all tasks, both with and without adaptive FC. On a group level, extreme adaptive FC did not change sound localization and speech understanding in bimodal listeners. Possible reasons are too strong compression ratios, insufficient residual hearing or that the adaptive switching, although preserving vowel perception, may have been ineffective to produce consistent ILD cues. Individual results suggested that two subjects were able to integrate the frequency-compressed HA input with that of the CI, and benefitted from enhanced binaural cues for horizontal sound localization.

  11. Electrothermal-electromagnetic hybrid thruster research

    NASA Technical Reports Server (NTRS)

    Kelly, A. J.; Jahn, R. G.; Myers, R.

    1987-01-01

    The energy deposition and acceleration mechanisms in the electrothermal-electromagnetic hybrid regime of coaxial plasma thruster operation are examined both theoretically and experimentally. Theoretical results show that the major trade-offs in the hybrid regime are between efficiency and specific impulse: increasing the influence of electromagnetic forces increases I(sp), but within the operating range examined, decreases the efficiency. Experiments conducted in the predominantly electromagnetic regime agree with the predictions. Anode power deposition is the dominant loss process.

  12. Accuracy of a teleported trapped field state inside a single bimodal cavity

    SciTech Connect

    Queiros, Iara P. de; Cardoso, W. B.; Souza, Simone; Almeida, N. G. de

    2007-09-15

    We propose a simplified scheme to teleport a superposition of coherent states from one mode to another of the same bimodal lossy cavity. Based on current experimental capabilities, we present a calculation of the fidelity that can be achieved, demonstrating accurate teleportation if the mean photon number of each mode is at most 1.5. Our scheme applies as well for teleportation of coherent states from one mode of a cavity to another mode of a second cavity, when both cavities are embedded in a common reservoir.

  13. Heat mode of bimodal solar system on Leo to Heo orbit

    NASA Astrophysics Data System (ADS)

    Kirillov, E. Ya.; Klimov, A. V.; Ogloblin, B. G.

    1997-01-01

    The development of a Bimodal Solar Power and Propulsion System capable of injecting a SV from an intermediate orbit to a geostationary one calls for an assessment of energy balance, of conditions for the SPPS coming up to the operating mode, and of temperature conditions during the injection to an orbit required. The paper considers thermal conditions of the SPPS generating capacity of which amounts to 4 kW, with 250 kg and 400 kg mass of heat accumulators during the injection into an operational orbit. Thermal conditions in the Earth's shadow when the SPPS is in the ecliptic plane are considered. A mathematical SPPS model and main results obtained are presented.

  14. Bimodal regulation of an Elk subfamily K+ channel by phosphatidylinositol 4,5-bisphosphate.

    PubMed

    Li, Xiaofan; Anishkin, Andriy; Liu, Hansi; van Rossum, Damian B; Chintapalli, Sree V; Sassic, Jessica K; Gallegos, David; Pivaroff-Ward, Kendra; Jegla, Timothy

    2015-11-01

    Phosphatidylinositol 4,5-bisphosphate (PIP2) regulates Shaker K+ channels and voltage-gated Ca2+ channels in a bimodal fashion by inhibiting voltage activation while stabilizing open channels. Bimodal regulation is conserved in hyperpolarization-activated cyclic nucleotide-gated (HCN) channels, but voltage activation is enhanced while the open channel state is destabilized. The proposed sites of PIP2 regulation in these channels include the voltage-sensor domain (VSD) and conserved regions of the proximal cytoplasmic C terminus. Relatively little is known about PIP2 regulation of Ether-á-go-go (EAG) channels, a metazoan-specific family of K+ channels that includes three gene subfamilies, Eag (Kv10), Erg (Kv11), and Elk (Kv12). We examined PIP2 regulation of the Elk subfamily potassium channel human Elk1 to determine whether bimodal regulation is conserved within the EAG K+ channel family. Open-state stabilization by PIP2 has been observed in human Erg1, but the proposed site of regulation in the distal C terminus is not conserved among EAG family channels. We show that PIP2 strongly inhibits voltage activation of Elk1 but also stabilizes the open state. This stabilization produces slow deactivation and a mode shift in voltage gating after activation. However, removal of PIP2 has the net effect of enhancing Elk1 activation. R347 in the linker between the VSD and pore (S4-S5 linker) and R479 near the S6 activation gate are required for PIP2 to inhibit voltage activation. The ability of PIP2 to stabilize the open state also requires these residues, suggesting an overlap in sites central to the opposing effects of PIP2 on channel gating. Open-state stabilization in Elk1 requires the N-terminal eag domain (PAS domain + Cap), and PIP2-dependent stabilization is enhanced by a conserved basic residue (K5) in the Cap. Our data shows that PIP2 can bimodally regulate voltage gating in EAG family channels, as has been proposed for Shaker and HCN channels. PIP2 regulation

  15. Micro-to-nano-scale deformation mechanisms of a bimodal ultrafine eutectic composite

    PubMed Central

    Lee, Seoung Wan; Kim, Jeong Tae; Hong, Sung Hwan; Park, Hae Jin; Park, Jun-Young; Lee, Nae Sung; Seo, Yongho; Suh, Jin Yoo; Eckert, Jürgen; Kim, Do Hyang; Park, Jin Man; Kim, Ki Buem

    2014-01-01

    The outstading mechanical properties of bimodal ultrafine eutectic composites (BUECs) containing length scale hierarchy in eutectic structure were demonstrated by using AFM observation of surface topography with quantitative height measurements and were interpreted in light of the details of the deformation mechanisms by three different interface modes. It is possible to develop a novel strain accommodated eutectic structure for triggering three different interface-controlled deformation modes; (I) rotational boundary mode, (II) accumulated interface mode and (III) individual interface mode. A strain accommodated microstructure characterized by the surface topology gives a hint to design a novel ultrafine eutectic alloys with excellent mechanical properties. PMID:25265897

  16. On the bimodal dynamics of the turbulent horseshoe vortex system in a wing-body junction

    NASA Astrophysics Data System (ADS)

    Paik, Joongcheol; Escauriaza, Cristian; Sotiropoulos, Fotis

    2007-04-01

    The turbulent boundary layer approaching a wall-mounted obstacle experiences a strong adverse pressure gradient and undergoes three-dimensional separation leading to the formation of a dynamically rich horseshoe vortex (HSV) system. In a pioneering experimental study, Devenport and Simpson [J. Fluid Mech. 210, 23 (1990)] showed that the HSV system forming at the leading edge region of a wing mounted on a flat plate at Re =1.15×105 exhibits bimodal, low-frequency oscillations, which away from the wall produce turbulent energy and stresses one order of magnitude higher than those produced by the conventional shear mechanism in the approaching turbulent boundary layer. We carry out numerical simulations for the experimental configuration of Devenport and Simpson using the detached-eddy-simulation (DES) approach. The DES length scale is adjusted for this flow to alleviate the well known shortcoming of DES; namely that of premature, laminar-like flow separation. The numerical simulations reproduce with good accuracy most experimental observations, including both the distributions of the mean flow and turbulence quantities and the bimodal dynamics of the velocity field in the HSV region. The only remaining discrepancy between experiments and simulations is the predicted location of the HSV, which is somewhat further upstream from the wing than the measured one. Proper orthogonal decomposition (POD) of the resolved flow field is employed to gain insights into the coherent dynamics of the flow. The POD analysis shows that 85% of the energy in the vortex region is accounted for by the first two POD modes whose dynamics is quasiperiodic. To elucidate the physical mechanisms that lead to the onset of the bimodal dynamics, we employ probability-density-function-based conditional averaging and visualization of the instantaneous three-dimensional structure of the HSV using the q criterion. We show that the bimodal dynamics is due to the continuous and aperiodic interplay of two

  17. Acute ethanol treatment induces a bimodal response of phospholipid acylation rates in rat red blood cells

    SciTech Connect

    Verine, A.; Valette, A.; Richard, D.; Boyer, J. )

    1991-01-01

    A single intraperitoneal injection of ethanol in rats elicited a bimodal response of acylation rates in phosphatidylcholine and phosphatidylethanolamine of intact red blood cells. Within an initial period, ethanol inhibited acylation rates. The inhibition then reversed, leading to increased values which persisted as long as ethanol was present in plasma. Acylation rates were not correlated to ethanol concentrations in plasma. The authors suggest that red cells first desensitize to, then overcompensate for the inhibitory effect of ethanol on acylation reactions. These adaptive changes may be one of the events mediating membrane tolerance to ethanol.

  18. Exploring the effects of hydrograph shape on unimodal and bimodal sediment mixtures.

    NASA Astrophysics Data System (ADS)

    Phillips, C. B.; Singer, M. B.; Hill, K. M.; Paola, C.

    2016-12-01

    Under steady flow within a river the rate of bed load transport has been shown to vary both spatially and temporally due to various hydrologic and granular phenomena. Variability within particle size distributions and their spatial arrangement on the river bed (e.g. armoring, segregation) has been observed to affect the flux for a particular value of the applied flow stress, while hydrology is primarily assumed to control the magnitude of applied bed stress. Prediction of bed load transport in natural rivers is further complicated due to the inherent transience within a flood hydrograph, however relatively little is known about how flood transience, intermittence and/or unsteadiness in flow, differs from steady flow. Here we investigate the role of flood transience for unimodal and bimodal bed load sediment transport through controlled laboratory flume experiments under the conditions of constant sediment feed with steady and unsteady flow. Experimental runs consist of sequences of steady or unsteady flood hydrographs with a variety of competent flow durations and peak stress magnitudes for both a unimodal and bimodal particle size distribution. We demonstrate for the unimodal sediment mixture that the total bed load flux for a flood scales linearly with the integrated excess transport capacity for both steady and unsteady flow, in agreement with prior field scale results. This indicates that to a first order the effects of flow unsteadiness and granular interactions are minimal for determining the bulk transport. Interestingly and in contrast to the unimodal mixture, the bimodal mixture behaves differently under steady and unsteady flow hydrographs, where unsteady flow conditions promote both greater degrees of armoring, bed patchiness, and size selective transport. We find that even under steady flow conditions the total flux output for the bimodal mixture can vary by a factor of five and depends strongly on the local bed state. These results suggest a surprising

  19. Micro-to-nano-scale deformation mechanisms of a bimodal ultrafine eutectic composite.

    PubMed

    Lee, Seoung Wan; Kim, Jeong Tae; Hong, Sung Hwan; Park, Hae Jin; Park, Jun-Young; Lee, Nae Sung; Seo, Yongho; Suh, Jin Yoo; Eckert, Jürgen; Kim, Do Hyang; Park, Jin Man; Kim, Ki Buem

    2014-09-30

    The outstading mechanical properties of bimodal ultrafine eutectic composites (BUECs) containing length scale hierarchy in eutectic structure were demonstrated by using AFM observation of surface topography with quantitative height measurements and were interpreted in light of the details of the deformation mechanisms by three different interface modes. It is possible to develop a novel strain accommodated eutectic structure for triggering three different interface-controlled deformation modes; (I) rotational boundary mode, (II) accumulated interface mode and (III) individual interface mode. A strain accommodated microstructure characterized by the surface topology gives a hint to design a novel ultrafine eutectic alloys with excellent mechanical properties.

  20. Atom-mediated effective interactions between modes of a bimodal cavity

    SciTech Connect

    Prado, F. O.; Luiz, F. S.; Villas-Boas, J. M.; Alcalde, A. M.; Duzzioni, E. I.; Sanz, L.

    2011-11-15

    We show a procedure for engineering effective interactions between two modes in a bimodal cavity. Our system consists of one or more two-level atoms, excited by a classical field, interacting with both modes. The two effective Hamiltonians have forms similar to beam-splitter and quadratic beam-splitter interactions. We also demonstrate that the nonlinear Hamiltonian can be used to prepare an entangled coherent state, also known as a multidimensional entangled coherent state, which has been pointed out as an important entanglement resource. We show that the nonlinear interaction parameter can be enhanced considering N independent atoms trapped inside a high-finesse optical cavity.

  1. T-cell-predominant lymphoid hyperplasia in a tattoo*

    PubMed Central

    Souza, Erica Sales; Rocha, Bruno de Oliveira; Batista, Everton da Silva; de Oliveira, Rodrigo Ferreira; Farre, Lourdes; Bittencourt, Achilea Lisboa

    2014-01-01

    Cutaneous lymphoid hyperplasia (CLH) can be idiopathic or secondary to external stimuli, and is considered rare in tattoos. The infiltrate can be predominantly of B or T-cells, the latter being seldom reported in tattoos. We present a case of a predominantly T CLH, secondary to the black pigment of tattooing in a 35-year-old patient, with a dense infiltrate of small, medium and scarce large T-cells. Analysis of the rearrangement of T-cells receptor revealed a polyclonal proliferation. Since the infiltrate of CLH can simulate a T lymphoma, it is important to show that lesions from tattoos can have a predominance of T-cells. PMID:25387518

  2. Career Advice: Finding a Job at a Predominantly Undergraduate Institution

    PubMed Central

    Ramirez, Julio J.

    2016-01-01

    Seeking a teaching job at a predominantly undergraduate college or university can be a daunting proposition. Although reports from the Bureau of Labor Statistics suggest that the job market for teaching positions at postsecondary institutions will be healthy over the coming decade, competition for these positions will likely be intense. This essay explores the profiles of predominantly undergraduate institutions (PUIs), the nature of faculty positions at PUIs, the elements that make for a competitive job applicant, and strategies to consider during negotiations. Seeking a position at a PUI may be arduous at times, but the rewards reaped from a successful search for a PUI position are well worth the investment. PMID:27385929

  3. Career Advice: Finding a Job at a Predominantly Undergraduate Institution.

    PubMed

    Ramirez, Julio J

    2016-01-01

    Seeking a teaching job at a predominantly undergraduate college or university can be a daunting proposition. Although reports from the Bureau of Labor Statistics suggest that the job market for teaching positions at postsecondary institutions will be healthy over the coming decade, competition for these positions will likely be intense. This essay explores the profiles of predominantly undergraduate institutions (PUIs), the nature of faculty positions at PUIs, the elements that make for a competitive job applicant, and strategies to consider during negotiations. Seeking a position at a PUI may be arduous at times, but the rewards reaped from a successful search for a PUI position are well worth the investment.

  4. Evidence for genetic exchange and hybridization in Trypanosoma cruzi based on nucleotide sequences and molecular karyotype.

    PubMed

    Brisse, Sylvain; Henriksson, Jan; Barnabé, Christian; Douzery, Emmanuel J P; Berkvens, Dirk; Serrano, Myrna; De Carvalho, Maria Ruth C; Buck, Gregory A; Dujardin, Jean-Claude; Tibayrenc, Michel

    2003-02-01

    Trypanosoma cruzi is thought to undergo predominant clonal evolution, as determined by population genetics studies. However, this model does not exclude occasional recombination, which existence is strongly suggested by several recent studies. We sequenced a portion of the maxicircle cytochrome b (CYb) gene and of the nuclear rRNA promoter region from representative strains of six T. cruzi genetic lineages isolated from anthroponotic environments and man (lineages IIb, IId and IIe), sylvatic environments (lineages IIa and IIc) or both (lineage I). Phylogenetic analyses based on the two genes were incongruent. Remarkably, in lineage IIe, CYb and rRNA sequences were very closely related to those of lineages IIc and IIb, respectively. One stock of lineage IId showed rRNA sequence heterogeneity, with both IIb-like and IIc-like copies. Analysis of the size variation of six distinct pairs of putative homologous chromosomes revealed a bimodal distribution of chromosomal sizes across T. cruzi. Notably, stocks of lineages IId and IIe had several chromosomal pairs distributed in distinct modes, with the corresponding modes individually found in lineages IIb and IIc. Together, these data indicate the origin of lineages IId and IIe by hybridization between representatives of lineages IIb and IIc. CYb and rRNA sequences clustered into three and four major lineages, respectively. Data were in agreement with the distinction of six genetic lineages, but not with their proposed grouping into two primary lineages, as lineage II was not monophyletic. Based on a CYb substitution rate of 1% per million years (Myr), the major lineages are estimated to have diverged around 10 million years ago.

  5. Stellarator hybrids

    SciTech Connect

    Furth, H.P.; Ludescher, C.

    1984-08-01

    The present paper briefly reviews the subject of tokamak-stellarator and pinch-stellarator hybrids, and points to two interesting new possibilities: compact-torus-stellarators and mirror-stellarators.

  6. The perception of consonants in reverberation and noise by adults fitted with bimodal devices

    PubMed Central

    Mason, Michelle; Kokkinakis, Kostas

    2014-01-01

    Purpose The purpose of this study was to evaluate the contribution of a contralateral hearing aid (HA) to the perception of consonants, in terms of voicing, manner, and place of articulation cues in reverberation and noise by adult cochlear implantees aided by bimodal fittings. Method Eight post-lingually deafened adult cochlear implant listeners with a fully inserted cochlear implant in one ear and low-frequency hearing in the other ear were tested on consonant perception. The subjects were presented with consonant stimuli processed in the following experimental conditions: one quiet condition, two different reverberation times (0.3 s and 1.0 s), and the combination of two reverberation times with a single signal-to-noise ratio (SNR = 5 dB). Results Consonant perception improved significantly when listening in combination with a contralateral hearing aid (HA) as opposed to listening with a cochlear implant (CI) alone in 0.3 s and 1.0 s of reverberation. Significantly higher scores were also noted when noise was added to 0.3 s of reverberation. Conclusion A considerable benefit was noted from the additional acoustic information in conditions of reverberation and reverberation plus noise. The bimodal benefit observed was more pronounced for voicing and manner of articulation than for place of articulation. PMID:24686826

  7. Trans-species learning of cellular signaling systems with bimodal deep belief networks.

    PubMed

    Chen, Lujia; Cai, Chunhui; Chen, Vicky; Lu, Xinghua

    2015-09-15

    Model organisms play critical roles in biomedical research of human diseases and drug development. An imperative task is to translate information/knowledge acquired from model organisms to humans. In this study, we address a trans-species learning problem: predicting human cell responses to diverse stimuli, based on the responses of rat cells treated with the same stimuli. We hypothesized that rat and human cells share a common signal-encoding mechanism but employ different proteins to transmit signals, and we developed a bimodal deep belief network and a semi-restricted bimodal deep belief network to represent the common encoding mechanism and perform trans-species learning. These 'deep learning' models include hierarchically organized latent variables capable of capturing the statistical structures in the observed proteomic data in a distributed fashion. The results show that the models significantly outperform two current state-of-the-art classification algorithms. Our study demonstrated the potential of using deep hierarchical models to simulate cellular signaling systems. The software is available at the following URL: http://pubreview.dbmi.pitt.edu/TransSpeciesDeepLearning/. The data are available through SBV IMPROVER website, https://www.sbvimprover.com/challenge-2/overview, upon publication of the report by the organizers. xinghua@pitt.edu Supplementary data are available at Bioinformatics online. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

  8. Magnetorheological behavior of magnetoactive elastomers filled with bimodal iron and magnetite particles

    NASA Astrophysics Data System (ADS)

    Sorokin, Vladislav V.; Stepanov, Gennady V.; Shamonin, Mikhail; Monkman, Gareth J.; Kramarenko, Elena Yu

    2017-03-01

    Magnetoactive elastomers (MAE) based on soft silicone matrices, filled with various proportions of large diameter (approximately 50 μm) iron and small diameter (approximately 0.5 μm) magnetite particles are synthesized. Their rheological behavior in homogeneous magnetic fields up to 600 mT is studied in detail. The addition of small magnetite particles facilitates fabrication of uniformly distributed magnetic elastomer composites by preventing aggregation and sedimentation of large particles during curing. It is shown that using the proposed bimodal filler particles it is possible to tailor various magnetorheological (MR) properties which can be useful for different target applications. In particular, either absolute or relative magnetorheological effects can be tuned. The value of the damping factor as well as the range of deformation amplitudes for the linear viscoelastic regime can be chosen. The interdependencies between different MR properties of bimodal MAEs are considered. The results are discussed in the model framework of particle network formation under the simultaneous influence of external magnetic fields and mechanical deformation.

  9. Separation of bimodal high density polyethylene using multidimensional high temperature liquid chromatography.

    PubMed

    Prabhu, K N; Brüll, R; Macko, T; Remerie, K; Tacx, J; Garg, P; Ginzburg, A

    2015-11-06

    High-temperature two-dimensional liquid chromatography (HT 2D-LC) using HT-HPLC as first dimension and HT-SEC as second dimension holds enormous potential to investigate the distribution according to molar mass and chemical composition of bimodal high density polyethylene (BiHDPE), as it avoids drawbacks of crystallization-based techniques. In this study, we have stepwise optimized the chromatographic parameters of 1D, comprising gradient slope and temperature, using model homo- and copolymers of ethylene with the aim to minimize the impact of molar mass on the compositional separation. Then the HT-HPLC was hyphenated to HT-SEC and optimum conditions for the volume of the sample transfer loop were probed with regard to the resolution of BiHDPE into the individual constituents HDPE and LLDPE. A particular important aspect was the use of infrared (IR) detection, and the demands it puts on the chromatographic aspects: We have shown that IR detection can be successfully applied in HT 2D-LC of BiHDPE, which is broadly distributed with regard to short chain branching and molar mass, only when the separation in 2D is optimized with regard to chromatographic resolution. As final result a bimodality is evident in the contour and the 3D surface plots as well as in both HPLC and SEC projections generated from HT 2D-LC.

  10. Distributions of nonlinear wave amplitudes and heights from laboratory generated following and crossing bimodal seas

    NASA Astrophysics Data System (ADS)

    Petrova, P. G.; Guedes Soares, C.

    2014-05-01

    This paper presents an analysis of the distributions of nonlinear crests, troughs and heights of deep water waves from mixed following sea states generated mechanically in an offshore basin and compares with previous results for mixed crossing seas from the same experiment. The random signals at the wavemaker in both types of mixed seas are characterized by bimodal spectra following the model of Guedes Soares (1984). In agreement with the Benjamin-Feir mechanism, the high-frequency spectrum shows a decrease in the peak magnitude and downshift of the peak with the distance, as well as reduction of the tail. The observed statistics and probabilistic distributions exhibit, in general, increasing effects of third-order nonlinearity with the distance from the wavemaker. However, this effect is less pronounced in the wave systems with two following wave trains than in the crossing seas, given that they have identical initial characteristics of the bimodal spectra. The relevance of third-order effects due to free modes only is demonstrated and assessed by excluding the vertically asymmetric distortions induced by bound wave effects of second and third order. The fact that for records characterized by relatively large coefficient of kurtosis, the empirical distributions for the non-skewed profiles continue deviating from the linear predictions, corroborate the relevance of free wave interactions and thus the need of using higher-order models for the description of wave data.

  11. Bimodal regime in young massive clusters leading to subsequent stellar generations

    NASA Astrophysics Data System (ADS)

    Wünsch, Richard; Palouš, Jan; Tenorio-Tagle, Guillermo; Muñoz-Tuñón, Casiana; Ehlerová, Soňa

    2017-03-01

    Massive stars in young massive clusters insert tremendous amounts of mass and energy into their surroundings in the form of stellar winds and supernova ejecta. Mutual shock-shock collisions lead to formation of hot gas, filling the volume of the cluster. The pressure of this gas then drives a powerful cluster wind. However, it has been shown that if the cluster is massive and dense enough, it can evolve in the so-called bimodal regime, in which the hot gas inside the cluster becomes thermally unstable and forms dense clumps which are trapped inside the cluster by its gravity. We will review works on the bimodal regime and discuss the implications for the formation of subsequent stellar generations. The mass accumulates inside the cluster and as soon as a high enough column density is reached, the interior of the clumps becomes self-shielded against the ionising radiation of stars and the clumps collapse and form new stars. The second stellar generation will be enriched by products of stellar evolution from the first generation, and will be concentrated near the cluster center.

  12. Wear behavior of light-cured resin composites with bimodal silica nanostructures as fillers.

    PubMed

    Wang, Ruili; Bao, Shuang; Liu, Fengwei; Jiang, Xiaoze; Zhang, Qinghong; Sun, Bin; Zhu, Meifang

    2013-12-01

    To enhance wear behavior of resin composites, bimodal silica nanostructures including silica nanoparticles and silica nanoclusters were prepared and proposed as fillers. The silica nanoclusters, a combination of individually dispersed silica nanoparticles and their agglomerations, with size distribution of 0.07-2.70 μm, were fabricated by the coupling reaction between amino and epoxy functionalized silica nanoparticles, which were obtained by the surface modification of silica nanoparticles (~70 nm) using 3-aminopropyl triethoxysilane (APTES) and 3-glycidoxypropyl trimethoxysilane (GPS) as coupling agents, respectively. Silica nanoparticles and nanoclusters were then silanized with 3-methacryloxypropyl trimethoxysilane (γ-MPS) to prepare composites by mixing with bisphenol A glycerolate dimethacrylate (Bis-GMA) and tri (ethylene glycol) dimethacrylate (TEGDMA). Experimental composites with various filler compositions were prepared and their wear behaviors were assessed in this work. The results suggested that composites with increasing addition of silica nanoparticles in co-fillers possessed lower wear volume and smoother worn surface. Particularly, the composite 53:17 with the optimum weight ratio of silica nanoparticles and silica nanoclusters presented the excellent wear behavior with respect to that of the commercial Esthet-X, although the smallest wear volume was achieved by Z350 XT. The introduction of bimodal silica nanostructures as fillers might provide a new sight for the design of resin composites with significantly improved wear resistance.

  13. Human Exploration Mission Capabilities to the Moon, Mars, and Near Earth Asteroids Using ''Bimodal'' NTR Propulsion

    SciTech Connect

    Stanley K. Borowski; Leonard A. Dudzinski; Melissa L. McGuire

    2000-06-04

    The nuclear thermal rocket (NTR) is one of the leading propulsion options for future human exploration missions because of its high specific impulse (Isp {approx} 850 to 1000 s) and attractive engine thrust-to-weight ratio ({approx} 3 to 10). Because only a minuscule amount of enriched {sup 235}U fuel is consumed in an NRT during the primary propulsion maneuvers of a typical Mars mission, engines configured both for propulsive thrust and modest power generation (referred to as 'bimodal' operation) provide the basis for a robust, power-rich stage with efficient propulsive capture capability at the moon and near-earth asteroids (NEAs), where aerobraking cannot be utilized. A family of modular bimodal NTR (BNTR) space transfer vehicles utilize a common core stage powered by three {approx}15-klb{sub f} engines that produce 50 kW(electric) of total electrical power for crew life support, high data rate communications with Earth, and an active refrigeration system for long-term, zero-boiloff liquid hydrogen (LH{sub 2}) storage. This paper describes details of BNTR engines and designs of vehicles using them for various missions.

  14. Human fatigue expression recognition through image-based dynamic multi-information and bimodal deep learning

    NASA Astrophysics Data System (ADS)

    Zhao, Lei; Wang, Zengcai; Wang, Xiaojin; Qi, Yazhou; Liu, Qing; Zhang, Guoxin

    2016-09-01

    Human fatigue is an important cause of traffic accidents. To improve the safety of transportation, we propose, in this paper, a framework for fatigue expression recognition using image-based facial dynamic multi-information and a bimodal deep neural network. First, the landmark of face region and the texture of eye region, which complement each other in fatigue expression recognition, are extracted from facial image sequences captured by a single camera. Then, two stacked autoencoder neural networks are trained for landmark and texture, respectively. Finally, the two trained neural networks are combined by learning a joint layer on top of them to construct a bimodal deep neural network. The model can be used to extract a unified representation that fuses landmark and texture modalities together and classify fatigue expressions accurately. The proposed system is tested on a human fatigue dataset obtained from an actual driving environment. The experimental results demonstrate that the proposed method performs stably and robustly, and that the average accuracy achieves 96.2%.

  15. Bilingualism alters brain functional connectivity between "control" regions and "language" regions: Evidence from bimodal bilinguals.

    PubMed

    Li, Le; Abutalebi, Jubin; Zou, Lijuan; Yan, Xin; Liu, Lanfang; Feng, Xiaoxia; Wang, Ruiming; Guo, Taomei; Ding, Guosheng

    2015-05-01

    Previous neuroimaging studies have revealed that bilingualism induces both structural and functional neuroplasticity in the dorsal anterior cingulate cortex (dACC) and the left caudate nucleus (LCN), both of which are associated with cognitive control. Since these "control" regions should work together with other language regions during language processing, we hypothesized that bilingualism may also alter the functional interaction between the dACC/LCN and language regions. Here we tested this hypothesis by exploring the functional connectivity (FC) in bimodal bilinguals and monolinguals using functional MRI when they either performed a picture naming task with spoken language or were in resting state. We found that for bimodal bilinguals who use spoken and sign languages, the FC of the dACC with regions involved in spoken language (e.g. the left superior temporal gyrus) was stronger in performing the task, but weaker in the resting state as compared to monolinguals. For the LCN, its intrinsic FC with sign language regions including the left inferior temporo-occipital part and right inferior and superior parietal lobules was increased in the bilinguals. These results demonstrate that bilingual experience may alter the brain functional interaction between "control" regions and "language" regions. For different control regions, the FC alters in different ways. The findings also deepen our understanding of the functional roles of the dACC and LCN in language processing. Copyright © 2015 Elsevier Ltd. All rights reserved.

  16. Efficient and reusable polyamide-56 nanofiber/nets membrane with bimodal structures for air filtration.

    PubMed

    Liu, Bowen; Zhang, Shichao; Wang, Xueli; Yu, Jianyong; Ding, Bin

    2015-11-01

    Nanofibrous media that both possess high airborne particle interception efficiency and robust air permeability would have broad technological implications for areas ranging from individual protection and industrial security to environmental governance; however, creating such filtration media has proved extremely challenging. Here we report a strategy to construct the bio-based polyamide-56 nanofiber/nets (PA-56 NFN) membranes with bimodal structures for effective air filtration via one-step electrospinning/netting. The PA-56 membranes are composed of completely covered two-dimensional (2D) ultrathin (∼20 nm) nanonets which are optimized by facilely regulating the solution concentration, and the bonded scaffold fibers constructed cavity structures which are synchronously created by using the CH3COOH inspiration. With integrated properties of small aperture, high porosity, and bonded scaffold, the resulting PA-56 NFN membranes exhibit high filtration efficiency of 99.995%, low pressure drop of 111 Pa, combined with large dust holding capacity of 49 g/m(2) and dust-cleaning regeneration ability, for filtrating ultrafine airborne particles in the most safe manner involving sieving principle and surface filtration. The successful synthesis of PA-56 NFN medium would not only make it a promising candidate for air filtration, but also provide new insights into the design and development of nanonet-based bimodal structures for various applications.

  17. N-Alkylfluorenyl-substituted N-heterocyclic carbenes as bimodal pincers.

    PubMed

    Teci, Matthieu; Brenner, Eric; Matt, Dominique; Gourlaouen, Christophe; Toupet, Loïc

    2015-05-21

    Two N-heterocyclic carbene precursors having their nitrogen atoms substituted by the expanded 9-ethyl-9-fluorenyl group, namely imidazolinium chloride 6 and imidazolium chloride 7, have been synthesized in high yields from fluorenone (1). The key intermediate of their syntheses is the new primary amine 9-ethyl-9-fluorenylamine (3), which was prepared in 75% yield. Both salts were readily converted into the corresponding PEPPSI-type palladium complexes, 8 and 9 (PEPPSI: pyridine-enhanced precatalyst preparation stabilisation and initiation). Despite rotational freedom of the ethylfluorenyl moieties about the N–C(fluorenyl) bond in their cationic precursors, the carbene ligands of the Pd(II)-complexes 8 and 9 both behave as bimodal pincers in solution and in the solid state, the resulting confinement being essentially due to (weak) attractive anagostic interactions between the CH2(fluorenyl) groups and the metal centre. Unlike in 8 and 9, there was no indication for similar anagostic interactions in the imidazolylidene chlorosilver complex 11, which could be obtained from 7. In the solid state, however, 11 adopts a remarkable “open sandwich” structure, with the two alkylfluorenilidene planes η2-bonded to the silver, this constituting a further bimodal pincer-type bonding mode of this ligand class. Complexes 8 and 9 were assessed in Suzuki–Miyaura cross-coupling reactions. The imidazolylidene complex 9 displayed high activity towards unencumbered aryl chlorides. Its activity is comparable to that of the previously reported, highly efficient benzimidazolylidene analogue 10.

  18. Timing of seed dispersal generates a bimodal seed bank depth distribution

    USGS Publications Warehouse

    Espinar, J.L.; Thompson, K.; Garcia, L.V.

    2005-01-01

    The density of soil seed banks is normally highest at the soil surface and declines monotonically with depth. Sometimes, for a variety of reasons, peak density occurs below the surface but, except in severely disturbed soils, it is generally true that deeper seeds are older. In seasonally dry habitats that develop deep soil cracks during the dry season, it is possible that some seeds fall down cracks and rapidly become deeply buried. We investigated this possibility for three dominant clonal perennials (Scirpus maritimus, S. litoralis, and Juncus subulatus) in the Don??ana salt marsh, a nontidal marsh with a Mediterranean climate located in southwest Spain. Two species, which shed most of their seed during the dry season and have seeds with low buoyancy, had bimodal viable seed depth distributions, with peak densities at the surface and at 16-20 cm. A third species, which shed most seeds after soil cracks had closed and had seeds with high buoyancy, had viable seeds only in surface soil. Bimodal seed bank depth distributions may be relatively common in seasonally dry habitats with fine-textured soils, but their ecological significance has not been investigated.

  19. The influence of grain size ratio upon the relative mobility in bimodal sediment mixtures

    NASA Astrophysics Data System (ADS)

    Dudill, Ashley; Frey, Philippe

    2014-05-01

    The behaviour of grain mixtures varies from that of uniform grain, which has implications for bedload sediment transport in gravel-bed rivers. In particular, sediment mixtures act to modify the level of mobility within the bed, leading to aggradation or degradation, which has significant implications for river stability. Previous work has reported upon this change in mobility within bimodal mixtures; however we do not know how far grain size ratio influences these results. We hypothesise that there is a link between the change in levels of mobility and the grain size ratio due to varying amounts of infiltration, which controls the hiding/exposure function. This poster will present experimental results from an investigation designed to isolate the influence of grain size ratio upon the change in levels of mobility in bimodal sediment mixtures. This experimental investigation was undertaken using various sizes of spherical particles in a relatively narrow flume. Using this arrangement, we are able to observe effects at the particle scale in order to understand the individual and bulk grain behaviour.

  20. Bimodal regime in young massive clusters leading to formation of subsequent stellar generations

    NASA Astrophysics Data System (ADS)

    Wunsch, Richard; Palous, Jan; Tenorio-Tagle, Guillermo; Munoz-Tunon, Casiana; Ehlerova, Sona

    2015-08-01

    Massive stars in young massive clusters insert tremendous amounts of mass and energy into their surroundings in the form of stellar winds and supernova ejecta. Mutual shock-shock collisions lead to formation of hot gas, filling the volume of the cluster. The pressure of this gas then drives a powerful cluster wind. However, it has been shown that if the cluster is massive and dense enough, it can evolve in the so called bimodal regime, in which the hot gas inside the cluster becomes thermally unstable and forms dense clumps which are trapped inside the cluster by its gravity.We will review works on the bimodal regime and discuss the implications for the formation of subsequent stellar generations. The mass accumulates inside the cluster and as soon as a high enough column density is reached, the interior of the clumps becomes self-shielded against the ionising radiation of, stars and the clumps collapse and form new stars. The second stellar generation will be enriched by products of the stellar evolution of the first generation, and will be concentrated near the cluster center.

  1. Social Mechanisms to Get People Outdoors: Bimodal Distribution of Interest in Nature?

    PubMed Central

    Buckley, Ralf Christopher; Westaway, Diane; Brough, Paula

    2016-01-01

    We report results from a post-program survey (n = 930) of participants in a non-profit outdoor health program targeted principally at women with families in Australia’s metropolitan cities. We analyze communications, motivations, experiences, satisfaction, and intentions. The program involves 3 months’ outdoor training in scenic locations, culminating in a single-day event. Training includes social opportunities and peer-group support. Event entry is in teams and includes charitable fundraising and personal challenges. Drop-out rates are very low, and repeat sign-up high. There are 2,000–3,600 places per event, and the most recent sold out in <24 h. We propose that for urban residents of developed nations, individual interest in exposure to nature may be bimodal rather than unimodal. Programs of this type target individuals most likely to shift from low-interest to high-interest mode, using a set of social levers to change attitudes and behaviors. This contrasts with most public outdoor health programs, which assume a unimodal distribution and aim for small lifestyle changes at population scale. We suggest that the bimodal hypothesis is relevant to the sociocultural context of psychosocial interventions in a public health context, and merits direct testing. PMID:27896265

  2. A long-term epigenetic memory switch controls bacterial virulence bimodality

    PubMed Central

    Ronin, Irine; Katsowich, Naama; Rosenshine, Ilan; Balaban, Nathalie Q

    2017-01-01

    When pathogens enter the host, sensing of environmental cues activates the expression of virulence genes. Opposite transition of pathogens from activating to non-activating conditions is poorly understood. Interestingly, variability in the expression of virulence genes upon infection enhances colonization. In order to systematically detect the role of phenotypic variability in enteropathogenic E. coli (EPEC), an important human pathogen, both in virulence activating and non-activating conditions, we employed the ScanLag methodology. The analysis revealed a bimodal growth rate. Mathematical modeling combined with experimental analysis showed that this bimodality is mediated by a hysteretic memory-switch that results in the stable co-existence of non-virulent and hyper-virulent subpopulations, even after many generations of growth in non-activating conditions. We identified the per operon as the key component of the hysteretic switch. This unique hysteretic memory switch may result in persistent infection and enhanced host-to-host spreading. DOI: http://dx.doi.org/10.7554/eLife.19599.001 PMID:28178445

  3. Investigation of mixed fluorinated and triblock copolymer liquid crystals: imprint for mesostructured bimodal silica.

    PubMed

    Assaker, Karine; Naboulsi, Issam; Stébé, Marie-José; Emo, Mélanie; Blin, Jean-Luc

    2015-05-15

    Due to the difference in «mutual phobicity» between fluorocarbon and hydrocarbon chains, mixtures of fluorinated and hydrogenated surfactants are excellent candidates to design bimodal systems having two types of mesopores. In literature, only a few papers deal with these bimodal systems. Here hexagonal liquid crystal mixtures of the polyoxyethylene fluoroalkyl ether [R(F)8(EO)9] and the Pluronic [P123] have been used to template this kind of mesostructure through the liquid crystal mechanism, which is barely considered. After the detailed investigation of the R(F)8(EO)9/P123/water liquid crystal domain, materials have been synthesized and characterized by small angle X-ray scattering, transmission electron microscopy and nitrogen adsorption-desorption analysis. Our results show that this system provides two separate pore sizes in the materials over the mesoporous range. The ratio between the small mesopores and the large ones depends on the proportion between the porogens in the mixture. Nonetheless, we also outline that a minimum quantity of silica is required to recover the two hexagonal networks. Copyright © 2015 Elsevier Inc. All rights reserved.

  4. Thermal decomposition behavior of amino groups modified bimodal mesoporous silicas as aspirin carrier.

    PubMed

    Gao, Lin; Sun, Jihong; Zhang, Li; Li, Yuzhen; Ren, Bo

    2011-12-01

    Two kinds of amino groups were employed to functionalize bimodal mesoporous silicas and related drug carriers were prepared. The characterization results of XRD, N2 adsorption and desorption, FT-IR and TG all confirmed the structural integrity of the bimodal mesopore architecture after introduction treatment of functional groups and the successful adsorption of aspirin. In order to investigate the interaction among the mesoporous structure, the functional groups grafted onto the mesoporous surface and the existential microenvironment of the drug molecules inside the mesoporous channels, the thermal decomposition behaviors of amino groups modified and aspirin loaded carriers were studied based on the thermogravimetric analysis in details. According to the thermogravimetry and derivative thermogravimetry results, the apparent activation energies E(a) of thermal decomposition for all related samples have been evaluated by Kissinger and Flynn-Wall-Ozawa methods. Meanwhile, their thermal decomposition mechanisms have been suggested by using Coats and Redfern methods. All these featured consequence could provide a deeper understanding for large loading capacity and controlled release of drug-carriers in the pharmaceutical application.

  5. Cochlear implant and hearing aid: a new approach to optimizing the fitting in this bimodal situation.

    PubMed

    Keilmann, Annerose M; Bohnert, Andrea M; Gosepath, Jan; Mann, Wolf J

    2009-12-01

    More and more patients with residual hearing on the contralateral side are becoming candidates for cochlear implants (CI) surgery due to increasing CI. The major benefits of regular binaural hearing are spatial hearing, localization, and signal source discrimination in both quiet and noisy surroundings. In most of the reports, hearing aid fitting was carried out without balancing both the devices. Twelve children and eight adults with residual hearing on the non-operated side were binaurally fitted. Our fitting procedure for the hearing aid was based on the desired sensation level [i/o] method. A loudness scaling was used to adjust the loudness perception monaurally and to balance the volume of both devices. Speech audiometry in quiet and noisy surroundings was conducted both monaurally and in the bimodal mode. The fitting was modified according to the respective test results. In all children and six adults, a measurable gain and/or a subjective improvement of speech perception was achieved. Two adult patients did not accept the new fitting. In seven younger children, loudness scaling was impossible to perform because of age. This was also the case with speech audiometry for two children. A structured bimodal fitting using loudness scaling for both the cochlear implant and the hearing aid results in a subjective and objective amelioration of the patient's hearing and speech perception.

  6. Cantilever energy effects on bimodal AFM: phase and amplitude contrast of multicomponent samples

    NASA Astrophysics Data System (ADS)

    Chakraborty, Ishita; Yablon, Dalia G.

    2013-11-01

    Bimodal atomic force microscopy (AFM) is a recently developed technique of dynamic AFM where a higher eigenmode of the cantilever is simultaneously excited along with the fundamental eigenmode. The effects of different operating parameters while imaging an impact copolymer blend of polypropylene (PP) and ethylene-propylene (E-P) rubber in bimodal mode are explored through experiments and numerical simulations. The higher mode amplitude and phase contrasts between the two components of the sample reverse at different points as the free amplitude of the higher eigenmode is increased. Three different regimes are identified experimentally depending on the relative contrast between the PP and the E-P rubber. It is observed that the kinetic energy and free air drive input energy of the two cantilever eigenmodes play a role in determining the regimes of operation. Numerical simulations conducted with appropriate tip-sample interaction forces support the experimental results. An understanding of these regimes and the associated cantilever dynamics will guide a rational approach towards selecting appropriate operating parameters.

  7. Cantilever energy effects on bimodal AFM: phase and amplitude contrast of multicomponent samples.

    PubMed

    Chakraborty, Ishita; Yablon, Dalia G

    2013-11-29

    Bimodal atomic force microscopy (AFM) is a recently developed technique of dynamic AFM where a higher eigenmode of the cantilever is simultaneously excited along with the fundamental eigenmode. The effects of different operating parameters while imaging an impact copolymer blend of polypropylene (PP) and ethylene-propylene (E-P) rubber in bimodal mode are explored through experiments and numerical simulations. The higher mode amplitude and phase contrasts between the two components of the sample reverse at different points as the free amplitude of the higher eigenmode is increased. Three different regimes are identified experimentally depending on the relative contrast between the PP and the E-P rubber. It is observed that the kinetic energy and free air drive input energy of the two cantilever eigenmodes play a role in determining the regimes of operation. Numerical simulations conducted with appropriate tip-sample interaction forces support the experimental results. An understanding of these regimes and the associated cantilever dynamics will guide a rational approach towards selecting appropriate operating parameters.

  8. Trans-species learning of cellular signaling systems with bimodal deep belief networks

    PubMed Central

    Chen, Lujia; Cai, Chunhui; Chen, Vicky; Lu, Xinghua

    2015-01-01

    Motivation: Model organisms play critical roles in biomedical research of human diseases and drug development. An imperative task is to translate information/knowledge acquired from model organisms to humans. In this study, we address a trans-species learning problem: predicting human cell responses to diverse stimuli, based on the responses of rat cells treated with the same stimuli. Results: We hypothesized that rat and human cells share a common signal-encoding mechanism but employ different proteins to transmit signals, and we developed a bimodal deep belief network and a semi-restricted bimodal deep belief network to represent the common encoding mechanism and perform trans-species learning. These ‘deep learning’ models include hierarchically organized latent variables capable of capturing the statistical structures in the observed proteomic data in a distributed fashion. The results show that the models significantly outperform two current state-of-the-art classification algorithms. Our study demonstrated the potential of using deep hierarchical models to simulate cellular signaling systems. Availability and implementation: The software is available at the following URL: http://pubreview.dbmi.pitt.edu/TransSpeciesDeepLearning/. The data are available through SBV IMPROVER website, https://www.sbvimprover.com/challenge-2/overview, upon publication of the report by the organizers. Contact: xinghua@pitt.edu Supplementary information: Supplementary data are available at Bioinformatics online. PMID:25995230

  9. Meaning and Implications of Being Labelled a Predominantly White Institution

    ERIC Educational Resources Information Center

    Bourke, Brian

    2016-01-01

    Institutions of higher learning are regularly identified in scholarship and conversation by their racial composition, which generally reflects a distinction between predominantly white institutions (PWIs), and minority-serving institutions (MSIs). While PWI is not an official designation for any institution in the United Stated, six categories of…

  10. Achievement in Predominantly Low SES/Hispanic Dual Language Schools

    ERIC Educational Resources Information Center

    Lindholm-Leary, Kathryn; Block, Nicholas

    2010-01-01

    The purpose of this study is to examine how 659 Hispanic students in dual language programs in segregated or predominantly Hispanic/low socio-economic status (SES) schools are performing on standardized tests compared to school and statewide comparison groups. Test results are presented from two separate studies of English language learner and…

  11. Job Satisfaction and College Faculty in Two Predominantly Black Institutions.

    ERIC Educational Resources Information Center

    Diener, Thomas

    1985-01-01

    Presents findings on the work attitudes of faculty members at two predominantly Black colleges. Like their colleagues elsewhere, the respondents feel strong degrees of career satisfaction, especially from such job factors as student growth, personal growth, schedule flexibility, and professional autonomy. Other factors, including some working…

  12. Thriving Latino Males in Selective Predominantly White Institutions

    ERIC Educational Resources Information Center

    Pérez, David; Sáenz, Victor B.

    2017-01-01

    Researchers focus disproportionately on the underperformance of Latino males in higher education. In response to this research gap, this study explores how Latino males conceptualized and embodied success at selective, predominantly White institutions. Using qualitative data available from "The National Study on Latino Male Achievement in…

  13. Communication Apprehension among Black Students on Predominantly White Campuses.

    ERIC Educational Resources Information Center

    Byrd, Marquita L.; Sims, Anntarie L.

    1987-01-01

    A study of 114 Black undergraduates in two predominantly White midwestern universities demonstrates that communication apprehension (CA) among Blacks appears to be an audience-based phenomenon. Black females scored lower than Black males on the Personal Report of Communication Apprehension-24 (PRCA-24). The higher the CA score, the higher the…

  14. Biracial Student Voices: Experiences at Predominantly White Institutions

    ERIC Educational Resources Information Center

    Banks, Willie L., Jr.

    2008-01-01

    The purpose of this study was to examine the experiences of biracial students with one parent of African American heritage attending Predominantly White Institutions (PWI) in the South. This study utilized a basic qualitative research design and was comprised of three phases: semi-structured individual interviews, responses to written prompts and…

  15. Academic Advising with Minority Students on Predominantly White Campuses.

    ERIC Educational Resources Information Center

    Burrell, Leon F.; Trombley, Toni B.

    1983-01-01

    Surveyed minority students (N=338) to determine their perception of academic advising on five predominantly White campuses. Findings suggest that minority students perceive academic advising as their most important support resource, particularly among freshmen and sophomores. Few minority students, however, indicated they would seek guidance from…

  16. Meaning and Implications of Being Labelled a Predominantly White Institution

    ERIC Educational Resources Information Center

    Bourke, Brian

    2016-01-01

    Institutions of higher learning are regularly identified in scholarship and conversation by their racial composition, which generally reflects a distinction between predominantly white institutions (PWIs), and minority-serving institutions (MSIs). While PWI is not an official designation for any institution in the United Stated, six categories of…

  17. The Predominance of Literacy Activities in Urban Early Childhood Education

    ERIC Educational Resources Information Center

    Liu, Daoying; Channell, Linda

    2015-01-01

    The purpose of this paper is to explore the predominance of literacy activities within the homes of African American toddlers in an urban setting in Mississippi. The data were collected through a Likert survey from parent participants in daycares, preschools, and churches, as well as institutions from five different parts of Jackson, MS. The…

  18. Influence of age, spatial memory, and ocular fixation on localization of auditory, visual, and bimodal targets by human subjects.

    PubMed

    Dobreva, Marina S; O'Neill, William E; Paige, Gary D

    2012-12-01

    A common complaint of the elderly is difficulty identifying and localizing auditory and visual sources, particularly in competing background noise. Spatial errors in the elderly may pose challenges and even threats to self and others during everyday activities, such as localizing sounds in a crowded room or driving in traffic. In this study, we investigated the influence of aging, spatial memory, and ocular fixation on the localization of auditory, visual, and combined auditory-visual (bimodal) targets. Head-restrained young and elderly subjects localized targets in a dark, echo-attenuated room using a manual laser pointer. Localization accuracy and precision (repeatability) were quantified for both ongoing and transient (remembered) targets at response delays up to 10 s. Because eye movements bias auditory spatial perception, localization was assessed under target fixation (eyes free, pointer guided by foveal vision) and central fixation (eyes fixed straight ahead, pointer guided by peripheral vision) conditions. Spatial localization across the frontal field in young adults demonstrated (1) horizontal overshoot and vertical undershoot for ongoing auditory targets under target fixation conditions, but near-ideal horizontal localization with central fixation; (2) accurate and precise localization of ongoing visual targets guided by foveal vision under target fixation that degraded when guided by peripheral vision during central fixation; (3) overestimation in horizontal central space (±10°) of remembered auditory, visual, and bimodal targets with increasing response delay. In comparison with young adults, elderly subjects showed (1) worse precision in most paradigms, especially when localizing with peripheral vision under central fixation; (2) greatly impaired vertical localization of auditory and bimodal targets; (3) increased horizontal overshoot in the central field for remembered visual and bimodal targets across response delays; (4) greater vulnerability to

  19. Effect of the bimodality of a QD array on the optical properties and threshold characteristics of QD lasers

    SciTech Connect

    Nadtochiy, A. M.; Mintairov, S. A.; Kalyuzhnyy, N. A.; Rouvimov, S. S.; Shernyakov, Yu. M.; Payusov, A. S.; Maximov, M. V.; Zhukov, A. E.

    2015-08-15

    Heterostructures with InGaAs quantum dots (QDs) are synthesized on vicinal GaAs (001) substrates. The photoluminescence (PL) spectra and threshold characteristics of edge-emitting QD lasers are studied in the temperature range 10-400 K. The structural properties of QDs are examined by transmission electron microscopy. Analysis of the PL spectra demonstrates the bimodality of the QD array, which leads to an unusual temperature behavior of the PL spectra and threshold current density. A model of the population of a bimodal QD array by carriers, describing the observed phenomena, is considered.

  20. Proposal for efficient mode converter based on cavity quantum electrodynamics dark mode in a semiconductor quantum dot coupled to a bimodal microcavity

    SciTech Connect

    Li, Jiahua; Yu, Rong; Ma, Jinyong; Wu, Ying

    2014-10-28

    The ability to engineer and convert photons between different modes in a solid-state approach has extensive technological implications not only for classical communication systems but also for future quantum networks. In this paper, we put forward a scheme for coherent mode conversion of optical photons by utilizing the intermediate coupling between a single quantum dot and a bimodal photonic crystal microcavity via a waveguide. Here, one mode of the photonic crystal microcavity is coherently driven by an external single-frequency continuous-wave laser field and the two cavity modes are not coupled to each other due to their orthogonal polarizations. The undriven cavity mode is thus not directly coupled to the input driving laser and the only way it can get light is via the quantum dot. The influences of the system parameters on the photon-conversion efficiency are analyzed in detail in the limit of weak probe field and it is found that high photon-conversion efficiency can be achieved under appropriate conditions. It is shown that the cavity dark mode, which is a superposition of the two optical modes and is decoupled from the quantum dot, can appear in such a hybrid optical system. We discuss the properties of the dark mode and indicate that the formation of the dark mode enables the efficient transfer of optical fields between the two cavity modes.

  1. INFORMATION ON THE MILKY WAY FROM THE 2MASS ALL SKY STAR COUNT: BIMODAL COLOR DISTRIBUTIONS

    SciTech Connect

    Chang, Chan-Kao; Lai, Shao-Yu; Peng, Ting-Hung; Ko, Chung-Ming E-mail: cmko@astro.ncu.edu.tw

    2012-11-10

    The J - K{sub s} color distributions (CDs) with a bin size of 0.05 mag has been carried out for the entire Milky Way using the Two Micron All Sky Survey Point Source Catalog (2MASS PSC). The CDs are bimodal, with a red peak at 0.8 < J - K{sub s} < 0.85 and a blue peak at 0.3 < J - K{sub s} < 0.4. The colors of the red peak are more or less the same for the whole sky, but those of the blue peak depend on Galactic latitude (J - K{sub s} {approx} 0.35 at low Galactic latitudes and 0.35 < J - K{sub s} < 0.4 for other sky areas). The blue peak dominates the bimodal CDs at low Galactic latitudes and becomes comparable with the red peak in other sky regions. In order to explain the bimodal distribution and the global trend shown by the all-sky 2MASS CDs, we assemble an empirical Hertzsprung-Russell (H-R) diagram, which is composed of observational-based near-infrared H-R diagrams and color-magnitude diagrams, and incorporate a Milky Way model. In the empirical H-R diagram, the main-sequence turn-off for stars in the thin disk is relatively bluer, (J - K{sub s} ){sub 0} = 0.31, compared with that of the thick disk which is (J - K{sub s} ){sub 0} = 0.39. The age of the thin/thick disk is roughly estimated to be around 4-5/8-9 Gyr according to the color-age relation of the main-sequence turn-off. In general, the 2MASS CDs can be treated as a tool to measure the age of the stellar population of the Milky Way in a statistical manner and to our knowledge it is the first attempt to do so.

  2. Novel "bi-modal" H2dedpa derivatives for radio- and fluorescence imaging.

    PubMed

    Ramogida, Caterina F; Murphy, Lisa; Cawthray, Jacqueline F; Ross, James D; Adam, Michael J; Orvig, Chris

    2016-09-01

    A novel pyridyl functionalized analog of the promising hexadentate (68)Ga(3+) chelate H2dedpa (N4O2, 1,2-[[6-carboxy-pyridin-2-yl]-methylamine]ethane) was successfully synthesized and characterized. This new bifunctional chelate (BFC) was used to prepare the first proof-of-principle bi-modal H2dedpa derivative for fluorescence and nuclear imaging. Two bi-modal H2dedpa derivatives were prepared: H2dedpa-propylpyr-FITC and H2dedpa-propylpyr-FITC-(N,N'-propyl-2-NI) (FITC=fluorescein, pyr=pyridyl functionalized, NI=nitroimidazole). The ligands possess the strong gallium-coordinating atoms contained within dedpa(2-) that are ideal for radiolabeling with (68)Ga(3+) for positron-emission tomography (PET) imaging, and two fluorophores for optical imaging. In addition, one analog contains two NI moieties for specific entrapment of the tracer in hypoxic cells. These new bi-modal analogs were compared to the native unfunctionalized H2dedpa scaffold to determine the extent to which the addition of pyridyl functionalization would affect metal coordination, and complex stability. The non-radioactive gallium complexes were tested in a 3D tumor spheroid model. The novel pyridyl bis-functionalized H2dedpa ligand, H2dedpa-propylpyr-NH2, was quantitatively radiolabeled with (67)Ga (RCY>99%) under reaction conditions commensurate with unfunctionalized H2dedpa (10min at room temperature) at ligand concentrations as low as 10(-5)M. The resultant (67)Ga-complex withstood transchelation to the in vivo metal-binding competitor apo-transferrin (2h at 37°C, 93% intact), signifying that [Ga(dedpa-propylpyr-NH2)](+) is a kinetically inert complex suitable for in vivo use, but exhibited slightly reduced stability compared to the native [(67)Ga(dedpa)] scaffold (>99% intact). Finally, bi-model fluorescent Ga-dedpa compounds were successfully imaged in a 3D tumor spheroid model. The Ga-dedpa-FITC-NI derivative was specifically localized in the central hypoxic core of the spheroid.

  3. Characteristic Scale and Bimodality in Galaxies: Cold Streams, Shock Heating, Feedback and Clustering

    NASA Astrophysics Data System (ADS)

    Dekel, Avishai; Birnboim, Yuval

    2004-12-01

    We address the origin of the robustly observed bi-modality in galaxy properties at a characteristic stellar mass of ~ 3 × 10 10Msolar. As seen in large surveys at low redshift and indicated at z ~ 1, less massive galaxies tend to be star-forming blue (some very blue) discs in the ``field'', correlated along a ``fundamental line'' of L/M, surface brightness, internal velocity and metallicity rising with mass. More massive galaxies are mostly spheroids of red (some very red) old stars in groups or clusters, with surface brightness and metallicity ~constant and halo M/L rising with mass. The spheroids tend to host AGNs. We propose that the bi-modality is the combined effect of the thermal history of the infalling gas and several feedback processes, aided by the gravitational growth of fluctuations into groups of galaxies. In haloes below a critical mass ~ 10 12Msolar, single discs are built by cold streams, not heated by a shock in the extended dark halo, yielding efficient early star formation. It is regulated by supernova and radiative feedback into a long sequence of bursts, giving rise to the blue galaxies along the fundamental line. Further grwoth along the blue sequence into L*-size galaxies is allowed above the threshold mass by mergers and by cold streams, especially in low density environments. This phase of star formation is possibly observed as LIRGs at z <~ 1 and as luminous dusty objects at z ~ 2. Only above the critical mass is the infalling gas shock-heated to near the virial temperature. This hot, dilute gas is vulnerable to feedback from an energetic source such as an AGN, which shuts off the cold gas supply and prevents further disc growth and star formation, especially in clustered galaxies. Subsequent passive evolution, accompanied by gas-poor mergeres, lead to ``red-and-dead'' massive spheroids sharing a common halo in a group, some existing already at z ~ 1. The critical mass is predicted to slightly rise with z. When the detailed models of

  4. Maintenance of strong morphological differentiation despite ongoing natural hybridization between sympatric species of Lomatia (Proteaceae)

    PubMed Central

    McIntosh, Emma J.; Rossetto, Maurizio; Weston, Peter H.; Wardle, Glenda M.

    2014-01-01

    Background and Aims When species cohesion is maintained despite ongoing natural hybridization, many questions are raised about the evolutionary processes operating in the species complex. This study examined the extensive natural hybridization between the Australian native shrubs Lomatia myricoides and L. silaifolia (Proteaceae). These species exhibit striking differences in morphology and ecological preferences, exceeding those found in most studies of hybridization to date. Methods Nuclear microsatellite markers (nSSRs), genotyping methods and morphometric analyses were used to uncover patterns of hybridization and the role of gene flow in morphological differentiation between sympatric species. Key Results The complexity of hybridization patterns differed markedly between sites, however, signals of introgression were present at all sites. One site provided evidence of a large hybrid swarm and the likely presence of multiple hybrid generations and backcrosses, another site a handful of early generational hybrids and a third site only traces of admixture from a past hybridization event. The presence of cryptic hybrids and a pattern of morphological bimodality amongst hybrids often disguised the extent of underlying genetic admixture. Conclusions Distinct parental habitats and phenotypes are expected to form barriers that contribute to the rapid reversion of hybrid populations to their parental character state, due to limited opportunities for hybrid/intermediate advantage. Furthermore, strong genomic filters may facilitate continued gene flow between species without the danger of assimilation. Stochastic fire events facilitate temporal phenological isolation between species and may partly explain the bi-directional and site-specific patterns of hybridization observed. Furthermore, the findings suggest that F1 hybrids are rare, and backcrosses may occur rapidly following these initial hybridization events. PMID:24489011

  5. Role of Saccharomyces boulardii in diarrhea predominant irritable bowel syndrome.

    PubMed

    Kabir, M A; Ishaque, S M; Ali, M S; Mahmuduzzaman, M; Hasan, M

    2011-07-01

    Several studies with probiotics have shown promising results in the treatment of IBS. One of the probiotics used was saccharomyces boulardii. This is a randomized double blind placebo controlled clinical trial of S. boulardii in diarrhoea predominant IBS and was carried out in the hospital of Bangabandhu Sheikh Mujib Medical University (BSMMU), Dhaka, Bangladesh from June 2004 to July 2005. Thirty five (35) patients were included in each of the control and study groups. The study group was treated with S. boulardii 250 mg twice daily orally for one month. Patients were evaluated before therapy, at the end of therapy and 30 days after end of therapy by a scoring system which included symptoms as well as personal and professional life. No significant difference between the two groups was found in any of the parameters evaluated on any of the observation days. S. boulardii treatment for 30 days in diarrhoea predominant IBS patients did not result in any improvement in this study.

  6. Chronic recurrent multifocal osteomyelitis exhibiting predominance of periosteal reaction.

    PubMed

    Queiroz, Rodolfo Mendes; Rocha, Pedro Henrique Pereira; Lauar, Lara Zupelli; Costa, Mauro José Brandão da; Laguna, Claudio Benedini; Oliveira, Rafael Gouvêa Gomes de

    2017-04-01

    Chronic recurrent multifocal osteomyelitis is an idiopathic nonpyogenic autoinflammatory bone disorder involving multiple sites, with clinical progression persisting for more than 6 months and which may have episodes of remission and exacerbation in the long term. It represents up to 2-5% of the cases of osteomyelitis, with an approximate incidence of up to 4/1,000,000 individuals, and average age of disease onset estimated between 8-11 years, predominantly in females. The legs are the most affected, with a predilection for metaphyseal regions along the growth plate. We describe the case of a female patient, aged 2 years and 5 months, with involvement of the left ulna, right jaw and left tibia, showing a predominance of periosteal reaction as main finding.

  7. Predominant cartilaginous hamartoma: an unusual variant of chondromatous hamartoma.

    PubMed

    Seda, Gilbert; Amundson, Dennis; Lin, Mercury Y

    2010-02-01

    Chondromatous hamartomas are the most common benign lung tumors and the third most common pulmonary nodule. Histologically, they are characteristically composed of hyaline cartilage mixed with fibromyxoid stroma and adipose tissue surrounded by epithelial cells. We report the case of a healthy, 60-year-old woman with an incidentally discovered chondromatous hamartoma that was thorascopically excised. Her pulmonary hamartoma was predominantly cartilaginous, which only occurs in 1% of hamartomas.

  8. Nephrotic presentation in hydatid cyst disease with predominant tubulointerstital disease

    PubMed Central

    Aziz, Feroz; Pandya, Tanmay; Patel, Himanshu V; Ramakrishna, Paladugu; Goplani, Kamal R; Gumber, Manoj; Vanikar, Aruna V; Kanodia, Kamal; Shah, Pankaj R; Trivedi, Hargovind L

    2009-01-01

    Renal involvement, which can rarely occur in echinococcosis, more commonly manifests as hydatid cyst of the kidney. Scattered case reports of nephrotic syndrome secondary to hydatid cyst in the liver or lung have been reported for over two decades. The glomerular picture varied from minimal change lesion to mesangiocapillary glomerulonephritis. We report a case of predominantly tubulointerstitial nephritis with mesangioproliferative glomerulonephritis in a patient with hepatic hydatid cyst which responded to cyst resection alone. PMID:21694917

  9. Predominance zone diagrams and their application to solvent extraction techniques.

    PubMed

    Páez-Hernández, M E; Ramírez, M T; Rojas-Hernández, A

    2000-01-24

    Predominance zone diagrams have been useful tools in solving problems in analytical chemistry. They can be used to establish the best conditions for separation of mixtures or to optimize recovery procedures for a given species. The few reports on predominance zone diagrams for the participant species in liquid-liquid extraction systems, describe their construction as diagrams of the Pourbaix type (epsilon/pH). With the generalized species and equilibria method (GSEM) it is possible to elaborate Predominance zone diagrams for extraction (PZDE) in proper spaces and with parameters strictly related to these processes such as pH and the volume ratio, r. Therefore, using the GSEM, PZDE that allow us to determine the best conditions for the extraction of a given substance have been elaborated. The stoichiometry of the species been extracted can also be determined from the experimental conditions. It has been demonstrated that with the GSEM, PZDE can be constructed for systems of one and two components. In this work, we intend to demonstrate that the algorithm is valid for the elaboration of PZDE in systems of three and four components. Examples of analytical interest are presented such as lead (II) extraction with diphenyltiocarbazone (dithizone) and that for cadmium (II) with 8-hydroxyquinolein (oxine) in chloroform. The influence of a masking agent, the etilendiaminotetraacetic acid (EDTA) over the extraction of both metals was also assessed.

  10. Lichen Planus With Predominate Plasma Cell Infiltrate: Two Case Reports.

    PubMed

    Dinh, Huyenlan; Seyffert, Jennifer; Lountzis, Nektarios I; Altman, Howard B; Oram, Christian; Purcell, Stephen M

    2017-02-01

    Lichen planus (LP) is a mucocutaneous inflammatory dermatitis of idiopathic origin that can involve the skin, mucous membranes, hair, and nails. LP has an associated set of characteristic histopathologic findings which include hyperkeratosis, vacuolization of the basal layer, Civatte bodies, wedge-shaped hypergranulosis, band-like lymphocytic infiltrate at the dermal epidermal junction, eosinophilic colloid bodies in the papillary dermis, and pigment incontinence. The infiltrate is usually composed of lymphocytes with few histiocytes, mast cells, and macrophages. The presence of plasma cell predominant infiltrate in LP has only been reported in four previous cases and 2 other cases of lichen nitidus. The authors report another 2 cases of LP with predominate plasma cell infiltrate in 2 female patients on the legs. The differential includes a drug-induced lichenoid reaction with predominate plasma cell infiltrate. However, there have been no case reports of that type of reaction. Because plasma cells are seen commonly in certain infectious diseases, malignancy, and macroglobulinemia, it is prudent to rule out those entities. Our patients responded well with a class 1 topical steroid, with improvement of their lower leg lesions within 1 month of treatment.

  11. Minimising Unnecessary Mastectomies in a Predominantly Chinese Community

    PubMed Central

    Tan, Mona P.; Sitoh, Nadya Y.; Sitoh, Yih Y.

    2015-01-01

    Background. Recent data shows that the use of breast conservation treatment (BCT) for breast cancer may result in superior outcomes when compared with mastectomy. However, reported rates of BCT in predominantly Chinese populations are significantly lower than those reported in Western countries. Low BCT rates may now be a concern as they may translate into suboptimal outcomes. A study was undertaken to evaluate BCT rates in a cohort of predominantly Chinese women. Methods. All patients who underwent surgery on the breast at the authors' healthcare facility between October 2008 and December 2011 were included in the study and outcomes of treatment were evaluated. Results. A total of 171 patients were analysed. Two-thirds of the patients were of Chinese ethnicity. One hundred and fifty-six (85.9%) underwent BCT. Ninety-eight of 114 Chinese women (86%) underwent BCT. There was no difference in the proportion of women undergoing BCT based on ethnicity. After a median of 49 months of follow-up, three patients (1.8%) had local recurrence and 5 patients (2.9%) suffered distant metastasis. Four patients (2.3%) have died from their disease. Conclusion. BCT rates exceeding 80% in a predominantly Chinese population are possible with acceptable local and distant control rates, thereby minimising unnecessary mastectomies. PMID:25692037

  12. Natural hybridization between extremely divergent chromosomal races of the common shrew (Sorex araneus, Soricidae, Soricomorpha): hybrid zone in European Russia.

    PubMed

    Bulatova, N; Jones, R M; White, T A; Shchipanov, N A; Pavlova, S V; Searle, J B

    2011-03-01

    The Moscow and Seliger chromosomal races of the common shrew differ by Robertsonian fusions and possibly whole-arm reciprocal translocations (WARTs) such that their F₁ hybrids produce a chain-of-eleven configuration at meiosis I and are expected to suffer substantial infertility. Of numerous hybrid zones that have been described in the common shrew, those between the Moscow and Seliger races involve the greatest chromosomal difference. We collected 211 individuals from this zone to generate a total dataset of 298 individuals from 187 unique global positioning system (GPS) locations within the vicinity of interracial contact. We used a geographic information system (GIS) to map the location of the hybrid zone, which follows a direct route between two lakes, as would be anticipated from tension zone theory. Even within the central area of the hybrid zone, there is a much higher frequency of pure race individuals than hybrid, making this a clear example of a bimodal zone in the sense of Jiggins & Mallet (2000). The zone runs through good habitat for common shrews, but nevertheless it is very narrow (standard cline widths: 3-4 km), as would be anticipated from low hybrid fitness. There is clear potential for an interruption to gene flow and build-up of reproductive isolation. As found in some other hybrid zones, there is a high frequency of novel genetic variants, in this case, new chromosomal rearrangements. Here, we report a de novo Robertsonian fission and a de novo reciprocal translocation, both for the first time in the common shrew. There is an extraordinarily high frequency of de novo mutations recorded in F₁ hybrids in the zone and we discuss how chromosomal instability may be associated with such hybrids. The occurrence of a de novo Robertsonian fission is of considerable significance because it provides missing evidence that fissions are the basis of the novel acrocentric forms found and apparently selected for in certain common shrew hybrid zones.

  13. Heatpipe power system and heatpipe bimodal system design and development options

    SciTech Connect

    Houts, M.G.; Poston, D.I.; Emrich, W.J. Jr.

    1997-02-01

    The Heatpipe Power System (HPS) is a potential, near-term, low-cost space fission power system. The Heatpipe Bimodal System (HBS) is a potential, near-term, low-cost space fission power and/or propulsion system. Both systems will be composed of independent modules, and all components operate within the existing databases. The HPS and HBS have relatively few system integration issues; thus, the successful development of a module is a significant step toward verifying system feasibility and performance estimates. A prototypic HPS module is being fabricated, and testing is scheduled to begin in November 1996. A successful test will provide high confidence that the HPS can achieve its predicted performance.

  14. Bimodal distribution of free tropospheric ozone over the tropical western Pacific revealed by airborne observations

    NASA Astrophysics Data System (ADS)

    Pan, L. L.; Honomichl, S. B.; Randel, W. J.; Apel, E. C.; Atlas, E. L.; Beaton, S. P.; Bresch, J. F.; Hornbrook, R.; Kinnison, D. E.; Lamarque, J.-F.; Saiz-Lopez, A.; Salawitch, R. J.; Weinheimer, A. J.

    2015-09-01

    A recent airborne field campaign over the remote western Pacific obtained the first intensive in situ ozone sampling over the warm pool region from oceanic surface to 15 km altitude (near 360 K potential temperature level). The new data set quantifies ozone in the tropical tropopause layer under significant influence of convective outflow. The analysis further reveals a bimodal distribution of free tropospheric ozone mixing ratio. A primary mode, narrowly distributed around 20 ppbv, dominates the troposphere from the surface to 15 km. A secondary mode, broadly distributed with a 60 ppbv modal value, is prominent between 3 and 8 km (320 K to 340 K potential temperature levels). The latter mode occurs as persistent layers of ozone-rich drier air and is characterized by relative humidity under 45%. Possible controlling mechanisms are discussed. These findings provide new insight into the physical interpretation of the "S"-shaped mean ozone profiles in the tropics.

  15. Labeling and Selective Inactivation of Gram-Positive Bacteria Employing Bimodal Photoprobes with Dual Readouts.

    PubMed

    Galstyan, Anzhela; Block, Desiree; Niemann, Silke; Grüner, Malte C; Abbruzzetti, Stefania; Oneto, Michele; Daniliuc, Constantin G; Hermann, Sven; Viappiani, Cristiano; Schäfers, Michael; Löffler, Bettina; Strassert, Cristian A; Faust, Andreas

    2016-04-04

    Carbohydrate-conjugated silicon(IV) phthalocyanines with bimodal photoactivity were developed as probes with both fluorescent labeling and photosensitizing capabilities, and the concomitant fluorescent labeling and photoinduced inactivation of Gram-positive and Gram-negative models was explored. The maltohexaose-conjugated photoprobe provides a dual readout to distinguish between both groups of pathogens, as only the Gram-positive species was inactivated, even though both appeared labeled with near-infrared luminescence. Antibiotic resistance did not hinder the phototoxic effect, as even the methicillin-resistant pathogen Staphylococcus aureus (MRSA) was completely photoinactivated. Time-resolved confocal fluorescence microscopy analysis suggests that the photoprobe sticks onto the outer rim of the microorganisms, explaining the resistance of Gram-negative species on the basis of their membrane constitution. The mannose-conjugated photoprobe yields a different readout because it is able to label and to inactivate only the Gram-positive strain.

  16. Heatpipe power system and heatpipe bimodal system design and development options

    NASA Technical Reports Server (NTRS)

    Houts, M. G.; Poston, D. I.; Emrich, W. J., Jr.

    1997-01-01

    The Heatpipe Power System (HPS) is a potential, near-term, low-cost space fission power system. The Heatpipe Bimodal System (HBS) is a potential, near-term, low-cost space fission power and/or propulsion system. Both systems will be composed of independent modules, and all components operate within the existing databases. The HPS and HBS have relatively few system integration issues; thus, the successful development of a module is a significant step toward verifying system feasibility and performance estimates. A prototypic HPS module is being fabricated, and testing is scheduled to begin in November 1996. A successful test will provide high confidence that the HPS can achieve its predicted performance.

  17. Zero Boil-Off System Design and Thermal Analysis of the Bimodal Thermal Nuclear Rocket

    SciTech Connect

    Christie, Robert J.; Plachta, David W.

    2006-01-20

    Mars exploration studies at NASA are evaluating vehicles that incorporate Bimodal Nuclear Thermal Rocket (BNTR) propulsion which use a high temperature nuclear fission reactor and hydrogen to produce thermal propulsion. The hydrogen propellant is to be stored in liquid state for periods up to 18 months. To prevent boil-off of the liquid hydrogen, a system of passive and active components are needed to prevent heat from entering the tanks and to remove any heat that does. This report describes the design of the system components used for the BNTR Crew Transfer Vehicle and the thermal analysis performed. The results show that Zero Boil-Off (ZBO) can be achieved with the electrical power allocated for the ZBO system.

  18. Bimodal wireless sensing with dual-channel wide bandgap heterostructure varactors

    SciTech Connect

    Deen, David A.; Osinsky, Andrei; Miller, Ross

    2014-03-03

    A capacitive wireless sensing scheme is developed that utilizes an AlN/GaN-based dual-channel varactor. The dual-channel heterostructure affords two capacitance plateaus within the capacitance-voltage (CV) characteristic, owing to the two parallel two-dimensional electron gases (2DEGs) located at respective AlN/GaN interfaces. The capacitance plateaus are leveraged for the definition of two resonant states of the sensor when implemented in an inductively-coupled resonant LRC network for wireless readout. The physics-based CV model is compared with published experimental results, which serve as a basis for the sensor embodiment. The bimodal resonant sensor is befitting for a broad application space ranging from gas, electrostatic, and piezoelectric sensors to biological and chemical detection.

  19. MAGNETIC COMPLEXITY AS AN EXPLANATION FOR BIMODAL ROTATION POPULATIONS AMONG YOUNG STARS

    SciTech Connect

    Garraffo, Cecilia; Drake, Jeremy J.; Cohen, Ofer

    2015-07-01

    Observations of young open clusters have revealed a bimodal distribution of fast and slower rotation rates that has proven difficult to explain with predictive models of spin down that depend on rotation rates alone. The Metastable Dynamo Model proposed recently by Brown, employing a stochastic transition probability from slow to more rapid spin down regimes, appears to be more successful but lacks a physical basis for such duality. Using detailed 3D MHD wind models computed for idealized multipole magnetic fields, we show that surface magnetic field complexity can provide this basis. Both mass and angular momentum losses decline sharply with increasing field complexity. Combined with observation evidence for complex field morphologies in magnetically active stars, our results support a picture in which young, rapid rotators lose angular momentum in an inefficient way because of field complexity. During this slow spin-down phase, magnetic complexity is eroded, precipitating a rapid transition from weak to strong wind coupling.

  20. Bimodal wireless sensing with dual-channel wide bandgap heterostructure varactors

    NASA Astrophysics Data System (ADS)

    Deen, David A.; Osinsky, Andrei; Miller, Ross

    2014-03-01

    A capacitive wireless sensing scheme is developed that utilizes an AlN/GaN-based dual-channel varactor. The dual-channel heterostructure affords two capacitance plateaus within the capacitance-voltage (CV) characteristic, owing to the two parallel two-dimensional electron gases (2DEGs) located at respective AlN/GaN interfaces. The capacitance plateaus are leveraged for the definition of two resonant states of the sensor when implemented in an inductively-coupled resonant LRC network for wireless readout. The physics-based CV model is compared with published experimental results, which serve as a basis for the sensor embodiment. The bimodal resonant sensor is befitting for a broad application space ranging from gas, electrostatic, and piezoelectric sensors to biological and chemical detection.

  1. Bimodal bilingualism as multisensory training?: Evidence for improved audiovisual speech perception after sign language exposure.

    PubMed

    Williams, Joshua T; Darcy, Isabelle; Newman, Sharlene D

    2016-02-15

    The aim of the present study was to characterize effects of learning a sign language on the processing of a spoken language. Specifically, audiovisual phoneme comprehension was assessed before and after 13 weeks of sign language exposure. L2 ASL learners performed this task in the fMRI scanner. Results indicated that L2 American Sign Language (ASL) learners' behavioral classification of the speech sounds improved with time compared to hearing nonsigners. Results indicated increased activation in the supramarginal gyrus (SMG) after sign language exposure, which suggests concomitant increased phonological processing of speech. A multiple regression analysis indicated that learner's rating on co-sign speech use and lipreading ability was correlated with SMG activation. This pattern of results indicates that the increased use of mouthing and possibly lipreading during sign language acquisition may concurrently improve audiovisual speech processing in budding hearing bimodal bilinguals.

  2. Comparing Raman and fluorescence lifetime spectroscopy from human atherosclerotic lesions using a bimodal probe.

    PubMed

    Dochow, Sebastian; Fatakdawala, Hussain; Phipps, Jennifer E; Ma, Dinglong; Bocklitz, Thomas; Schmitt, Michael; Bishop, John W; Margulies, Kenneth B; Marcu, Laura; Popp, Jürgen

    2016-09-01

    Fluorescence lifetime imaging (FLIm) and Raman spectroscopy are two promising methods to support morphological intravascular imaging techniques with chemical contrast. Both approaches are complementary and may also be used in combination with OCT/IVUS to add chemical specificity to these morphologic intravascular imaging modalities. In this contribution, both modalities were simultaneously acquired from two human coronary specimens using a bimodal probe. A previously trained SVM model was used to interpret the fluorescence lifetime data; integrated band intensities displayed in RGB false color images were used to interpret the Raman data. Both modalities demonstrate unique strengths and weaknesses and these will be discussed in comparison to histologic analyses from the two coronary arteries imaged.

  3. One-step solvothermal synthesis of targetable optomagnetic upconversion nanoparticles for in vivo bimodal imaging.

    PubMed

    Wang, Xu; Chen, Jia-Tong; Zhu, Haomiao; Chen, Xueyuan; Yan, Xiu-Ping

    2013-11-05

    Bionanoparticles and nanostructures with high biocompatibility and stability, low toxicity, diversification of imaging modality, and specificity of targeting to desired organs or cells are of great interest in nanobiology and medicine. However, integrating all of these desired features into a single bionanoparticle, which can be applied to biomedical applications and eventually in clinical prediagnosis and therapy, is still a challenge. We herein report a facile one-step solvothermal approach to fabricate targetable and biocompatible β-NaYF4:Yb,Gd,Tm upconversion nanoparticles (UCNPs) with bimodal-signals (near-infrared (NIR) fluorescence and magnetic resonance (MR) signals) using hyaluronic acid (HA) as a multifunctional molecule. The prepared UCNPs with low toxicity are successfully applied for in vitro and in vivo targeted tumor imaging. The developed biomimetic surface modification approach for the synthesis of biomolecule-guided multifunctional UCNPs holds great potential applications in medical diagnostics and therapy.

  4. The nature of the bimodal luminosity distribution of ultraluminous X-ray pulsars

    NASA Astrophysics Data System (ADS)

    Grebenev, S. A.

    2017-07-01

    The mechanism that can be responsible for the bimodal luminosity distribution of super-Eddington X-ray pulsars in binary systems is pointed out. The transition from the high to low state of these objects is explained by accretion flow spherization due to the radiation pressure at certain (high) accretion rates. The transition between the states can be caused by a gradual change in the accretion rate. The complex behavior of the recently discovered ultraluminous X-ray pulsars M 82 X-2, NGC 5907 ULX-1, and NGC 7793 P13 is explained by the proposed mechanism. The proposed model also naturally explains the measured spinup of the neutron star in these pulsars, which is slower than the expected one by several times.

  5. O(+) and He(+) restricted and extended (bi-modal) ion conic distributions

    NASA Technical Reports Server (NTRS)

    Peterson, W. K.; Collin, H. L.; Doherty, M. F.; Bjorklund, C. M.

    1992-01-01

    An automated procedure using standard image processing techniques has been developed that finds and characterizes energetic ion conic events in the data acquired by the Energetic Ion Composition Spectrometer on DE-1 in the altitude range 8000 to 24000 km. The algorithm discriminates between the two types of ion conic distribution, those restricted to a narrow angular range and those extended in angle. Extended (bimodal) ion conic distributions also have a significant flux of field-aligned energetic ions. Extended ion conics constitute more than one third of the ion conics found. The two types of ion conic distribution have different altitude dependences. The average properties of energetic conic distributions suggest that conic formation by localized, explosive, transverse energization is not the dominant mechanism responsible for producing energetic conic distributions above 8000 km.

  6. Size evolution of highly amphiphilic macromolecular solution assemblies via a distinct bimodal pathway

    PubMed Central

    Kelley, Elizabeth G.; Murphy, Ryan P.; Seppala, Jonathan E.; Smart, Thomas P.; Hann, Sarah D.

    2014-01-01

    The solution self-assembly of macromolecular amphiphiles offers an efficient, bottom-up strategy for producing well--defined nanocarriers, with applications ranging from drug delivery to nanoreactors. Typically, the generation of uniform nanocarrier architecturesis controlled by processing methods that rely upon cosolvent mixtures. These preparation strategies hinge on the assumption that macromolecular solution nanostructures are kinetically stable following transfer from an organic/aqueous cosolvent into aqueous solution. Herein we demonstrate that unequivocal step-change shifts in micelle populations occur over several weeks following transfer into a highly selective solvent. The unexpected micelle growth evolves through a distinct bimodal distribution separated by multiple fusion events and critically depends on solution agitation. Notably, these results underscore fundamental similarities between assembly processes in amphiphilic polymer, small molecule, and protein systems. Moreover, the non-equilibrium micelle size increase can have a major impact on the assumed stability of solution assemblies, for which performance is dictated by nanocarrier size and structure. PMID:24710204

  7. O(+) and He(+) restricted and extended (bi-modal) ion conic distributions

    NASA Technical Reports Server (NTRS)

    Peterson, W. K.; Collin, H. L.; Doherty, M. F.; Bjorklund, C. M.

    1992-01-01

    An automated procedure using standard image processing techniques has been developed that finds and characterizes energetic ion conic events in the data acquired by the Energetic Ion Composition Spectrometer on DE-1 in the altitude range 8000 to 24000 km. The algorithm discriminates between the two types of ion conic distribution, those restricted to a narrow angular range and those extended in angle. Extended (bimodal) ion conic distributions also have a significant flux of field-aligned energetic ions. Extended ion conics constitute more than one third of the ion conics found. The two types of ion conic distribution have different altitude dependences. The average properties of energetic conic distributions suggest that conic formation by localized, explosive, transverse energization is not the dominant mechanism responsible for producing energetic conic distributions above 8000 km.

  8. Zero Boil-Off System Design and Thermal Analysis of the Bimodal Thermal Nuclear Rocket

    NASA Astrophysics Data System (ADS)

    Christie, Robert J.; Plachta, David W.

    2006-01-01

    Mars exploration studies at NASA are evaluating vehicles that incorporate Bimodal Nuclear Thermal Rocket (BNTR) propulsion which use a high temperature nuclear fission reactor and hydrogen to produce thermal propulsion. The hydrogen propellant is to be stored in liquid state for periods up to 18 months. To prevent boil-off of the liquid hydrogen, a system of passive and active components are needed to prevent heat from entering the tanks and to remove any heat that does. This report describes the design of the system components used for the BNTR Crew Transfer Vehicle and the thermal analysis performed. The results show that Zero Boil-Off (ZBO) can be achieved with the electrical power allocated for the ZBO system.

  9. Assessment of an SP-100 Bi-Modal Propulsion and Power System

    NASA Astrophysics Data System (ADS)

    Buksa, John J.; Demuth, Scott; Huber, Todd

    1994-07-01

    The attractiveness of using the SP-100 space nuclear power system for both electric power production and direct thermal propulsion is discussed. A conceptual modification to the SP-100 generic flight system that uses its hot, primary coolant to directly heat hydrogen propellant is presented. An analytical model of the system and its orbital-mechanical behavior is presented and used to assess the benefits of a number of orbital transfer missions. Both a 500 kW and a 2.4 MW system are assessed. Preliminary results indicate that for LEO-to-GEO transfers, the SP-100 bi-modal system offers a 100 % increase in payload over conventional chemical-only propulsion systems with transfer times on the order of days.

  10. Biodegradable microparticles with surface dimples as a bi-modal imaging contrast agent.

    PubMed

    Kim, Mi Ri; Lim, Yong Taik; Cho, Kuk Young

    2013-03-12

    Fabrication of physically engineered colloids and their application to the biological fields is emerging importance because of their potential to provide an enhanced performance without altering the chemical properties of biomaterials used. A facile approach is reported to fabricate sub-10-μm-sized PLGA microparticle with small dimples covering the surface by droplet imprinting. Optical and magnetic resonance bioimaging agents are easily co-encapsulated inside the microparticles to obtain a bi-modal imaging agent. Cell internalization efficacy of dimpled particles in DC 2.4 cell is enhanced compared with conventional smooth round-shaped colloids. Our result indicates that morphology-controlled microparticles show promise as a cell labeling with improved cell interaction.

  11. Bimodal spatial distribution of macular pigment: evidence of a gender relationship

    NASA Astrophysics Data System (ADS)

    Delori, François C.; Goger, Douglas G.; Keilhauer, Claudia; Salvetti, Paola; Staurenghi, Giovanni

    2006-03-01

    The spatial distribution of the optical density of the human macular pigment measured by two-wavelength autofluorescence imaging exhibits in over half of the subjects an annulus of higher density superimposed on a central exponential-like distribution. This annulus is located at about 0.7° from the fovea. Women have broader distributions than men, and they are more likely to exhibit this bimodal distribution. Maxwell's spot reported by subjects matches the measured distribution of their pigment. Evidence that the shape of the foveal depression may be gender related leads us to hypothesize that differences in macular pigment distribution are related to anatomical differences in the shape of the foveal depression.

  12. Bimodal quasi-oscillatory and spectral behavior in Scorpius X-1

    NASA Technical Reports Server (NTRS)

    Priedhorsky, W.; Hasinger, G.; Lewin, W. H. G.; Middleditch, J.; Parmar, A.

    1986-01-01

    Exosat observations of Sco X-1 obtained using the Xe and/or Ar detectors for a total of about 80,000 s during four runs on August 24-27, 1985 are reported and analyzed. Two modes of quasi-periodic oscillations (QPOs) corresponding to the quiescent and active states of Sco X-1 and to two modes of spectral behavior are identified and characterized, confirming the findings of Priedhorsky (1985) and Middleditch and Priedhorsky (1986). In the quiescent state, the QPO frequency is about 6 Hz and is anticorrelated with intensity, and the spectral hardness ratio (14-21 vs 2-7 keV) varies steeply with intensity; in the active state, QPO frequency is correlated with intensity and varies from 10 to 20 Hz, and the spectral-hardness-ratio/intensity curve is flatter. Previous observations of bimodal behavior in other bands are summarized, and theoretical models proposed to explain them are discussed.

  13. Superferromagnetism in mechanically alloyed fcc Fe23Cu77 with bimodal cluster size distribution

    NASA Astrophysics Data System (ADS)

    Silva, N. J. O.; Amaral, J. S.; Amaral, V. S.; Costa, B. F. O.; LeCaër, G.

    2009-01-01

    Magnetic measurements, x-ray diffraction and Mössbauer spectroscopy were used to characterize a nanostructured fcc Fe23Cu77 at.% alloy prepared by high-energy ball-milling, addressing in particular the effect of clustering on the nature of the interacting magnetic entities. The interpretation of magnetization measurements leads to the conclusion that grains, whose mean size is ~16 nm, contain two populations of magnetic Fe-rich nanoclusters with a bimodal size distribution. These two sets of clusters contain about 14 and 400 Fe atoms and have magnetic moments of 30 µB and 860 µB, respectively. The inter-cluster ferromagnetic interactions that lead to superferromagnetism with a Curie temperature TC~220 K can be described by a mean field determined by the smaller clusters only, which account for 90% of the magnetization.

  14. Characterization of a contemporaneous hybrid zone between two darter species (Etheostoma bison and E. caeruleum) in the Buffalo River System.

    PubMed

    Bossu, Christen M; Near, Thomas J

    2013-03-01

    Hybrid zones have long intrigued evolutionary biologists and provide a natural laboratory to explore the evolution of reproductive isolation (speciation). Molecular characterization of hybrid zone dynamics can provide insight into the strength of reproductive isolation as well as the underlying evolutionary processes shaping gene flow. Approximately one-third of darter species naturally hybridize making this species-rich North American freshwater teleost fish clade an ideal system to investigate the extent and direction of hybridization. The objective of this study was to use diagnostic microsatellite markers to calculate genetic hybrid index scores of two syntopic, but distantly related darter species, Etheostoma bison and Etheostoma caeruleum. A combination of hybrid index scores, assignment tests, and mitochondrial haplotype profiles uncovered mixed ancestry in approximately 6 % of sampled adult individuals, supporting contemporaneous hybridization that was previously undocumented in E. bison. Moreover, hybrids were not limited to the F1 generation, but encompassed the entire suite of hybrid categories (F1, F2 and backcross hybrids). The low number of hybrids assigned to each hybrid category represents a bimodal hybrid zone, suggesting reproductive isolation is strong (but incomplete) and also advocates for the ability of hybrids to produce second-generation hybrids and backcross into both parental species, mediating introgression across species boundaries. To this end, cytonuclear profiles of the sampled parental species and hybrids were consistent with bidirectional gene flow, although there was an overall trend of asymmetric hybridization between E. caeruleum females and E. bison males. The spatiotemporal variation in hybridization rates and resulting cytonuclear patterns expanded on in this study provide a comparative genetic framework on which future studies can begin to elucidate the underlying processes that not only generate a mosaic hybrid zone, but

  15. An investigation of bimodal jet trajectory in flow through scaled models of the human vocal tract

    NASA Astrophysics Data System (ADS)

    Erath, Byron D.; Plesniak, Michael W.

    2006-05-01

    Pulsatile two-dimensional flow through static divergent models of the human vocal folds is investigated. Although the motivation for this study is speech production, the results are generally applicable to a variety of engineering flows involving pulsatile flow through diffusers. Model glottal divergence angles of 10, 20, and 40° represent various geometries encountered in one phonation cycle. Frequency and amplitude of the flow oscillations are scaled with physiological Reynolds and Strouhal numbers typical of human phonation. Glottal velocity trajectories are measured along the anterior-posterior midline by using phase-averaged particle image velocimetry to acquire 1,000 realizations at ten discrete instances in the phonation cycle. The angular deflection of the glottal jet from the streamwise direction (symmetric configuration) is quantified for each realization. A bimodal flow configuration is observed for divergence angles of 10 and 20°, with the flow eventually skewing and attaching to the vocal fold walls. The deflection of the flow toward the vocal fold walls occurs when the forcing function reaches maximum velocity and zero acceleration. For a divergence angle of 40°, the flow never attaches to the vocal fold walls; however, there is increased variability in the glottal jet after the forcing function reaches maximum velocity and zero acceleration. The variation in the jet trajectory as a function of divergence angle is explained by performance maps of diffuser flow regimes. The smaller angle cases are in the unstable transitory stall regime while the 40° divergent case is in the fully developed two-dimensional stall regime. Very small geometric variations in model size and surface finish significantly affect the flow behavior. The bimodal, or flip-flopping, glottal jet behavior is expected to influence the dipole contribution to sound production.

  16. Dual Language Use in Sign-Speech Bimodal Bilinguals: fNIRS Brain-Imaging Evidence

    PubMed Central

    Kovelman, Ioulia; Shalinsky, Mark H.; White, Katherine S.; Schmitt, Shawn N.; Berens, Melody S.; Paymer, Nora; Petitto, Laura-Ann

    2009-01-01

    The brain basis of bilinguals’ ability to use two languages at the same time has been a hotly debated topic. On the one hand, behavioral research has suggested that bilingual dual language use involves complex and highly principled linguistic processes. On the other hand, brain-imaging research has revealed that bilingual language switching involves neural activations in brain areas dedicated to general executive functions not specific to language processing, such as general task maintenance. Here we address the involvement of language-specific versus cognitive-general brain mechanisms for bilingual language processing by studying a unique population and using an innovative brain-imaging technology: bimodal bilinguals proficient in signed and spoken languages and functional Near-Infrared Spectroscopy (fNIRS; Hitachi ETG-4000), which, like fMRI, measures hemodynamic change, but which is also advanced in permitting movement for unconstrained speech and sign production. Participant groups included (i) hearing ASL-English bilinguals, (ii) ASL monolinguals, and (iii) English monolinguals. Imaging tasks included picture naming in “Monolingual mode” (using one language at a time) and in “Bilingual mode” (using both languages either simultaneously or in rapid alternation). Behavioral results revealed that accuracy was similar among groups and conditions. By contrast, neuroimaging results revealed that bilinguals in Bilingual mode showed greater signal intensity within posterior temporal regions (“Wernicke’s area”) than in Monolingual mode. Significance: Bilinguals’ ability to use two languages effortlessly and without confusion involves the use of language-specific posterior temporal brain regions. This research with both fNIRS and bimodal bilinguals sheds new light on the extent and variability of brain tissue that underlies language processing, and addresses the tantalizing questions of how language modality, sign and speech, impact language

  17. Noninvasive MRI-SERS Imaging in Living Mice Using an Innately Bimodal Nanomaterial

    PubMed Central

    Yigit, Mehmet V.; Zhu, Leyun; Ifediba, Marytheresa A.; Zhang, Yong; Carr, Kevin; Moore, Anna; Medarova, Zdravka

    2011-01-01

    We report a novel nanomaterial (AuMN-DTTC) that can be used as a bimodal contrast agent for in vivo magnetic resonance imaging (MRI) and Raman spectroscopy. The probe consists of MRI-active superparamagnetic iron oxide nanoparticles, stably complexed with gold nanostructures. The gold component serves as a substrate for a Raman active dye molecule to generate a surface-enhanced Raman scattering (SERS) effect. The synthesized probe produces T2 weighted contrast and can be used as a SERS active material both in silico (in aqueous solution) and in vivo. A quantitative assessment of T2 relaxation times was obtained using multiecho MRI analysis. The T2 relaxation times of AuMN-DTTC and MN (dextran-coated iron oxide nanoparticles) were 29.23 + 1.45, and 31.58 + 1.7 msec, respectively. The SERS signature of AuMN-DTTC revealed peaks at 508, 629, 782, 844, 1080, 1108, 1135, and 1242 cm−1. Intramuscular administration of the probe resulted in a decrease of the T2 relaxation time of muscle from 33.4 + 2.5 msec to 20.3 + 2.2. SERS peaks were observed at 508, 629, 782, 844, 1080, 1108, 1135, and 1242 cm−1, consistent with the in silico results. Our studies illustrate for the first time the design and in vivo application of a contrast agent, whose component modalities include MRI and SERS. The value of this agent lies in its innately bimodal nature and its application in vivo for molecular imaging applications. PMID:21194236

  18. Bimodal behavior and isobestic transition pathway in surface plasmon resonance sensing

    PubMed Central

    Dhawan, Anuj; Canva, Michael; Vo-Dinh, Tuan

    2012-01-01

    In traditional interpretation of surface plasmon resonance (SPR) sensing and imaging data, total surface coverage of adsorbed or deposited chemical and biological molecules is generally assumed. This homogenous assumption leads to the modeling of monomodal propagation of plasmons on the surface of the metallic film corresponding to a certain relative permittivity and thickness of the medium—such as molecular thin film—next to the metal. In actual SPR Imaging (SPRI) and SPR sensing situations, the plasmonics-active platforms (e.g., biochips) employed may capture the biomolecular targets as aggregates of different domain sizes on the surface of the thin metallic films. Indeed, such binding of target material always has a finite thickness and is characterized by aggregate lateral sizes possibly varying from tens of nanometers to hundreds of micrometers. This paper studies the propagation of surface plasmons in metallic films, with dielectric domain sizes varying within such ranges. Through rigorous coupled wave analysis (RCWA) calculations, it is indicated that when the domain size is small, only a single mode of propagation—i.e. ‘monomodal’ propagation behavior—occurs as indicated by only one dip in the angular reflectance curves associated with metallic film having a periodically structured array of molecules on its surface. On the other hand, as the domain size is increased, there is a transition from the ‘monomodal propagation behavior’ to the existence of a ‘mixture of monomodal and bimodal propagation behavior’, which changes to a purely ‘bimodal behavior’ after the size of the domain periodicity is increased beyond about ten micron. Such a transition pathway clearly exhibits isobestic points. The calculations presented in this paper can enable correct interpretation of experimental angular or spectral reflectance data. PMID:23188328

  19. Bimodal Distribution of Geyser Preplay Eruptions: Lone Star Geyser, Yellowstone National Park

    NASA Astrophysics Data System (ADS)

    Namiki, A.; Hurwitz, S.; Murphy, F.; Manga, M.

    2014-12-01

    Geyser eruption intervals are determined by rates of water and heat discharge into shallow subsurface reservoirs and the conduit. In some geysers, small amounts of water discharge prior to a main eruption ('Preplay') can affect eruption intervals. Water discharge during preplay reduces the hydrostatic pressure, which in turn, induces boiling of water that is at, or near the critical temperature. Ascending steam slugs from depth can also lead to shorter eruption intervals (Namiki et al., 2014). In April 2014, we carried a five day experiment at Lone Star Geyser, Yellowstone National Park. Eruptions and their preplays were recorded with an infrared sensor that measured temperature variations immediately above the geyser cone (3.4~m high), temperature loggers that measured water temperature at the base of the cone and in the outflow channels, and visual observations. At Lone Star Geyser, during the preplay phase of the eruption, mainly liquid water is erupted, whereas the main phase of the eruption begins with the liquid-water dominated eruption and turns into the steam discharge. The temperature rise in an outflow channel indicates the occurrence of preplays and initiation of the main eruption. The acquired data suggests that the preplay patterns of Lone Star Geyser are vigorous and complex, consistent with previous observations (Karlstrom et al., 2013). Our new observations reveal two typical styles: 1) vigorous preplays with few events (<5) and long intervals (>20~minutes) that last approximately 40~minutes, and 2) less vigorous preplays that include several events (>5) with short intervals (few minutes), and continue approximately for one hour. Probability distributions of preplay durations show two peaks indicating the bimodal activity. The bimodality of Lone Star preplays may be a result of subtle change of temperature distribution in a convecting reservoir which has been observed in laboratory experiments (Toramaru and Maeda, 2013).

  20. Development of a steady state creep behavior model of polycrystalline tungsten for bimodal space reactor application

    SciTech Connect

    Purohit, A.; Hanan, N.A.; Bhattacharyya, S.K.; Gruber, E.E.

    1995-02-01

    The fuel element for one of the many reactor concepts being currently evaluated for bimodal applications in space consists of spherical fuel particles clad with tungsten or alloys of tungsten. The fuel itself consists of stabilized UO{sub 2}. One of the life limiting phenomena for the fuel element is failure of the cladding because of creep deformation. This report summarizes the information available in literature regarding the creep deformation of tungsten and its alloys and proposes a relation to be used for calculating the creep strains for elevated temperatures in the low stress region ({sigma} {le} 20 MPa). Also, results of the application of this creep relation to one of the reactor design concepts (NEBA-3) are discussed. Based on the traditional definition of creep deformation, the temperatures of 1500 K to 2900 K for tungsten and its alloys are considered to be in the {open_quotes}high{close_quotes} temperature range. In this temperature range, the rate controlling mechanisms for creep deformation are believed to be non-conservative motion of screw dislocations and short circuit diffusional paths. Extensive theoretical work on creep and in particular for creep of tungsten and its alloys have been reported in the literature. These theoretical efforts have produced complex mathematical models that require detailed materials properties. These relations, however, are not presently suitable for the creep analysis because of lack of consistent material properties required for their use. Variations in material chemistry and thermomechanical pre-treatment of tungsten have significant effects on creep and the mechanical properties. Analysis of the theoretical models and limited data indicates that the following empirical relation originally proposed by M. Jacox of INEL and the Air Force Phillips Laboratory, for calculating creep deformation of tungsten cladding, can be used for the downselection of preliminary bimodal reactor design concepts.

  1. Effect of meta-carborane on segmental dynamics in a bimodal Poly(dimethylsiloxane) network

    SciTech Connect

    Lewicki, J; Maxwell, R S; Patel, M; Herberg, J; Swain, A C; Liggat, J; Pethrick, R

    2008-06-11

    Bimodal networks of polydimethylsiloxane (PDMS) filled with varying amounts of icosahedral meta-carborane (m-CB) have been developed and characterized by broadband dielectric spectroscopy (BDS) and static {sup 1}H Multiple Quantum Nuclear Magnetic Resonance (MQ NMR). Both BDS and MQ NMR showed evidence for a decrease in the polymer chain dynamics. BDS spectra quantified a normal-mode relaxation near 40 Hz at 40 C. The frequency maximum observed for filled samples decreased with increasing m-CB content until contents greater than 5 wt. %. The width of the relaxation spectrum increased with the addition of small quantities of filler and decreased with filler contents greater that 5 wt. %. Agglomeration effects were observed at loadings greater than 5 wt % as manifest by the onset of low frequency Maxwell-Wagner-Sillars (MWS) processes. The MQ NMR data allowed the characterization of distributions of the residual dipolar couplings, <{Omega}{sub d}> and thus in the dynamic order parameter, Sb, consistent with the bimodal network architecture expected from the synthesis protocol used. Upon addition of less than 10 wt.% m-CB filler, the mean <{Omega}{sub d}> for the longer chains increased by 46% and the width of the distribution increased by 33%. The mean <{Omega}{sub d}> for the shorter chains increased by much less, indicative of preferential dispersion of the filler particles in the long chain domains of the network structure. We conclude that the mechanism of reinforcement is likely a free volume space filling at low loadings transitioning to complex molecular filler and polymer chain interaction phenomena at higher loadings.

  2. The Effect of Bimodal Input on Implicit and Explicit Memory: An Investigation into the Benefits of Within-Language Subtitling.

    ERIC Educational Resources Information Center

    Bird, Stephen A.; Williams, John N.

    2002-01-01

    Two experiments examined the effect of single-modality (sound or text) and bimodal (sound and text) presentation on word meaning, as measured by both improvements in spoken word recognition efficiency and recognition memory. Both native and nonnative speakers of English were tested. Concludes simultaneous text presentation can aid novel word…

  3. The Benefits of Bimodal Aiding on Extended Dimensions of Speech Perception: Intelligibility, Listening Effort, and Sound Quality.

    PubMed

    Devocht, Elke M J; Janssen, A Miranda L; Chalupper, Josef; Stokroos, Robert J; George, Erwin L J

    2017-01-01

    The benefits of combining a cochlear implant (CI) and a hearing aid (HA) in opposite ears on speech perception were examined in 15 adult unilateral CI recipients who regularly use a contralateral HA. A within-subjects design was carried out to assess speech intelligibility testing, listening effort ratings, and a sound quality questionnaire for the conditions CI alone, CIHA together, and HA alone when applicable. The primary outcome of bimodal benefit, defined as the difference between CIHA and CI, was statistically significant for speech intelligibility in quiet as well as for intelligibility in noise across tested spatial conditions. A reduction in effort on top of intelligibility at the highest tested signal-to-noise ratio was found. Moreover, the bimodal listening situation was rated to sound more voluminous, less tinny, and less unpleasant than CI alone. Listening effort and sound quality emerged as feasible and relevant measures to demonstrate bimodal benefit across a clinically representative range of bimodal users. These extended dimensions of speech perception can shed more light on the array of benefits provided by complementing a CI with a contralateral HA.

  4. The Benefits of Bimodal Aiding on Extended Dimensions of Speech Perception: Intelligibility, Listening Effort, and Sound Quality

    PubMed Central

    Chalupper, Josef

    2017-01-01

    The benefits of combining a cochlear implant (CI) and a hearing aid (HA) in opposite ears on speech perception were examined in 15 adult unilateral CI recipients who regularly use a contralateral HA. A within-subjects design was carried out to assess speech intelligibility testing, listening effort ratings, and a sound quality questionnaire for the conditions CI alone, CIHA together, and HA alone when applicable. The primary outcome of bimodal benefit, defined as the difference between CIHA and CI, was statistically significant for speech intelligibility in quiet as well as for intelligibility in noise across tested spatial conditions. A reduction in effort on top of intelligibility at the highest tested signal-to-noise ratio was found. Moreover, the bimodal listening situation was rated to sound more voluminous, less tinny, and less unpleasant than CI alone. Listening effort and sound quality emerged as feasible and relevant measures to demonstrate bimodal benefit across a clinically representative range of bimodal users. These extended dimensions of speech perception can shed more light on the array of benefits provided by complementing a CI with a contralateral HA. PMID:28874096

  5. Speech perception and localisation with SCORE bimodal: a loudness normalisation strategy for combined cochlear implant and hearing aid stimulation.

    PubMed

    Francart, Tom; McDermott, Hugh

    2012-01-01

    A significant fraction of newly implanted cochlear implant recipients use a hearing aid in their non-implanted ear. SCORE bimodal is a sound processing strategy developed for this configuration, aimed at normalising loudness perception and improving binaural loudness balance. Speech perception performance in quiet and noise and sound localisation ability of six bimodal listeners were measured with and without application of SCORE. Speech perception in quiet was measured either with only acoustic, only electric, or bimodal stimulation, at soft and normal conversational levels. For speech in quiet there was a significant improvement with application of SCORE. Speech perception in noise was measured for either steady-state noise, fluctuating noise, or a competing talker, at conversational levels with bimodal stimulation. For speech in noise there was no significant effect of application of SCORE. Modelling of interaural loudness differences in a long-term-average-speech-spectrum-weighted click train indicated that left-right discrimination of sound sources can improve with application of SCORE. As SCORE was found to leave speech perception unaffected or to improve it, it seems suitable for implementation in clinical devices.

  6. Microfluidic study of competence regulation in Streptococcus mutans: environmental inputs modulate bimodal and unimodal expression of comX

    PubMed Central

    Son, Minjun; Ahn, Sang-Joon; Guo, Qiang; Burne, Robert A.; Hagen, Stephen J.

    2012-01-01

    Summary Streptococcus mutans regulates genetic competence through a complex network that receives inputs from a number of environmental stimuli, including two signaling peptides designated as CSP and XIP. The response of the downstream competence genes to these inputs shows evidence of stochasticity and bistability and has been difficult to interpret. We have used microfluidic, single-cell methods to study how combinations of extracellular signals shape the response of comX, an alternative sigma factor governing expression of the late competence genes. We find that the composition of the medium determines which extracellular signal (XIP or CSP) can elicit a response from comX and whether that response is unimodal or bimodal across a population of cells. In a chemically defined medium, exogenous CSP does not induce comX, whereas exogenous XIP elicits a comX response from all cells. In complex medium, exogenous XIP does not induce comX, whereas CSP elicits a bimodal comX response from the population. Interestingly, bimodal behavior required an intact copy of comS, which encodes the precursor of XIP. The comS-dependent capability for both unimodal and bimodal response suggests that a constituent – most likely peptides – of complex medium interacts with a positive feedback loop in the competence regulatory network. PMID:22845615

  7. Head Shadow, Squelch, and Summation Effects with an Energetic or Informational Masker in Bilateral and Bimodal CI Users

    ERIC Educational Resources Information Center

    Pyschny, Verena; Landwehr, Markus; Hahn, Moritz; Lang-Roth, Ruth; Walger, Martin; Meister, Hartmut

    2014-01-01

    Purpose: The objective of the study was to investigate the influence of noise (energetic) and speech (energetic plus informational) maskers on the head shadow (HS), squelch (SQ), and binaural summation (SU) effect in bilateral and bimodal cochlear implant (CI) users. Method: Speech recognition was measured in the presence of either a competing…

  8. Direct one-pot synthesis of glutathione capped hydrophilic FePt-CdS nanoprobe for efficient bimodal imaging application.

    PubMed

    Jha, Deepak K; Saikia, Koushik; Chakrabarti, Srijita; Bhattacharya, Kakoli; Varadarajan, Komanduri S; Patel, Anant B; Goyary, Danswrang; Chattopadhyay, P; Deb, P

    2017-03-01

    One-pot synthesis methods for development of hydrophilic imaging nanoprobes have advantages over multi-pot methods due to their simple procedures, less probability for degradation of efficiency, superior control over growth and morphology, cost effectiveness, improved scope for scale-up synthesis etc. Here, we present a novel one-pot facile synthesis of hydrophilic colloidal bimodal nanoprobe (FePt-CdS) prepared through a seed-mediated nucleation and growth technique. In this facile synthesis of complex nanostructure, glutathione (GSH) was used as the capping agent to render biocompatibility and dispersibility. The microstructure, surface, optical, magnetic, biocompatibility, relaxivity and imaging property of the developed nanoprobe have been studied. The microstructural characterizations reveal average size of the particle as ~9-11nm with bleb shaped morphology. Spectroscopic characterization depicts the development of GSH capped CdS QDs on FePt, surface functionalities and their stability. The magnetic measurements confirm the superparamagnetic property in the developed bimodal nanoprobe. In addition, the GSH capping imparts excellent biocompatibility, water dispersibility, and fluorescence property to the probe. In RAW 264.7 macrophage cells, the bimodal nanoprobes exhibit intense green and red fluorescence. The magnetic resonance imaging (MRI) and fluorescence imaging (FI) study depict high transverse relaxivity and visible range fluorescent property in the synthesized FePt-CdS nanoprobe. Hence, the developed bimodal nanoprobe can be used as a potential candidate in simultaneous FI and MR imaging. Copyright © 2016 Elsevier B.V. All rights reserved.

  9. The Effect of Bimodal Input on Implicit and Explicit Memory: An Investigation into the Benefits of Within-Language Subtitling.

    ERIC Educational Resources Information Center

    Bird, Stephen A.; Williams, John N.

    2002-01-01

    Two experiments examined the effect of single-modality (sound or text) and bimodal (sound and text) presentation on word meaning, as measured by both improvements in spoken word recognition efficiency and recognition memory. Both native and nonnative speakers of English were tested. Concludes simultaneous text presentation can aid novel word…

  10. Phase functions, glories, fogbows and coronas for clouds with mirror-transformed gamma- and bimodal-distributions

    NASA Astrophysics Data System (ADS)

    Kablukova, Evgeniya G.; Prigarin, Sergei M.; Rozhenko, Sergei A.

    2015-11-01

    In this paper we study the phase functions for water-droplet clouds and fogs computed by the Mie theory for specific bimodal and "mirror"- transformed droplet size gamma-distributions. In addition, we construct images of coronas, fogbows and glory that can occur for such cloud and fog models.

  11. Photocatalytic Applications of Electrospun TiO2 Nanofibres Embedded with Bimodal Sized and Prismatic Gold Nanoparticles.

    PubMed

    Gopika, G; Asha, A M; Sivakumar, N; Balakrishnan, A; Nair, S V; Subramanian, K R V

    2015-09-01

    In this paper, we have synthesized electrospun TiO2 nanofibers embedded with bimodal sized and prismatic gold nanoparticles. The surface plasmons generated in the gold nanoparticles were used to enhance the performance of photocatalysis. The photocatalytic conversion efficiencies of these bimodal sized/prismatic gold nanoparticles when embedded in electrospun TiO2 fibres showed an enhancement of upto 60% over bare fiber systems and also show higher efficiencies than electrospun fibrous systems embedded with unimodal sized gold nanoparticles. Anisotropic bimodal gold nanoparticles show the highest degree of photocatalytic activity. This may be attributed to greater density/concentration of nanoparticles with higher effective surface area and formation of a junction between the smaller and larger nanoparticles. Such a bimodally distributed range of nanoparticles could also lead to greater trapping of charge carriers at the TiO2 conduction band edge and promoting catalytic reactions on account of these trapped charges. This enhanced photocatalytic activity is explained by invoking different operating mechanisms such as improved surface area, greater trapping, coarse plasmon resonance and band effects. Thus, a useful applicability of the gold nanoparticles is shown in the area of photocatalysis.

  12. Head Shadow, Squelch, and Summation Effects with an Energetic or Informational Masker in Bilateral and Bimodal CI Users

    ERIC Educational Resources Information Center

    Pyschny, Verena; Landwehr, Markus; Hahn, Moritz; Lang-Roth, Ruth; Walger, Martin; Meister, Hartmut

    2014-01-01

    Purpose: The objective of the study was to investigate the influence of noise (energetic) and speech (energetic plus informational) maskers on the head shadow (HS), squelch (SQ), and binaural summation (SU) effect in bilateral and bimodal cochlear implant (CI) users. Method: Speech recognition was measured in the presence of either a competing…

  13. Phenocryst-poor rhyolites of bimodal, tholeiitic provinces: the Rattlesnake Tuff and implications for mush extraction models

    NASA Astrophysics Data System (ADS)

    Streck, Martin J.; Grunder, Anita L.

    2008-01-01

    We consider the origin of rhyolites associated with tholeiitic basalt in bimodal provinces, as exemplified by the Rattlesnake Tuff of the High Lava Plains of eastern Oregon, in comparison to rhyolites associated with calcalkaline suites in light of recent models of extraction of rhyolite from crystal mush (Hildreth, J Volcanol Geotherm Res, 136:169 198, 2004; Bachmann and Bergantz, J Petrol, 45:1565 1582, 2004). The High Lava Plains encompass a strongly bimodal, tholeiite-rhyolite suite, spatially and compositionally related to the Snake River Plain and Yellowstone Plateau. In our assessment we draw the distinction between fractionation dominated processes to make rhyolites from rhyolites and processes required to make the parental rhyolite melt. New isotopic data and compositional zoning profiles in phenocrysts confirm that crystal fractionation dominated the generation of progressively more evolved, discrete rhyolites in the zoned Rattlesnake Tuff and are consistent with an origin of the least evolved high-silica rhyolites by partial melting of a mafic crust. While the most evolved rhyolites are compositionally virtually indistinguishable from those of calcalkaline suites, the parental rhyolites from bimodal suites are more Fe-rich than their calcalkaline counterparts. Oxygen isotope thermometry yields pre-eruptive temperatures of 860°C, in keeping with 800 880°C zircon saturation temperatures. High magmatic temperatures are common among rhyolites of bimodal suites, distinguishing them from cooler rhyolites of calcalkaline suites. Extraction of interstitial melt from a granodioritic mush cannot produce compositions of the Rattlesnake Tuff on the basis of major and trace element arguments (especially Fe, Ba, Sr, and Eu) and on the basis of temperature considerations. Chemically viable parental crystal mushes are syenite and alkali (A-type) granites for the production of all more evolved Rattlesnake Tuff rhyolites; ferro-dacitic mush is required for production of

  14. [A Case of Musicophilia with Right Predominant Temporal Lobe Atrophy].

    PubMed

    Shinagawa, Shunichiro; Nakayama, Kazuhiko

    2015-11-01

    A 68-year-old woman exhibiting musicophilia with right predominant temporal lobe atrophy happened to visit our clinic. She had no musical background, but beginning two years ago, she acquired a strong preference for especially popular music and sometimes sang at home. She did not exhibit obvious semantic aphasia or facial agnosia, and showed only mild behavioral changes including apathy. Her musicophilia can be explained as an instance of stereotypical behavior. Her right temporal lobe atrophy may have caused changes in her emotional and reward systems, resulting in her music specific behaviors.

  15. Lymphocyte-predominant Hodgkin disease: a comprehensive overview.

    PubMed

    Bose, Sumit; Ganesan, Chitra; Pant, Manish; Lai, Catherine; Tabbara, Imad A

    2013-02-01

    Lymphocyte-predominant Hodgkin disease is a rare form of Hodgkin lymphoma that is recognized as a separate histopathological entity. This disease tends to have multiple relapses, but has an overall good prognosis. Owing to its rarity, and the prolonged time period between recurrence and transformation events, there is no consensus regarding optimal management. However, the National Comprehensive Cancer Network guidelines indicate that for early stages, appropriate treatment is radiotherapy. Several management options have been reported including observation, radiation, chemotherapy, combined chemoradiotherapy, and anti-CD20 antibody therapy. Salvage therapy remains effective in inducing prolonged remission in patients with relapsed/refractory disease.

  16. Hybrid zone structure and the potential role of selection in hybridizing populations of native westslope cutthroat trout (Oncorhynchus clarki lewisi) and introduced rainbow trout (O. mykiss).

    PubMed

    Rubidge, Emily M; Taylor, Eric B

    2004-12-01

    Introgressive hybridization is a common feature of many zones of contact between divergent lineages of fishes. This is particularly common when taxa that are normally allopatric come into artificial (human-induced) secondary contact. We examined 18 native populations of westslope cutthroat trout (Oncorhynchus clarki lewisi, WCT) to determine the extent of introgressive hybridization with introduced rainbow trout (O. mykiss, RBT) and the genetic structure of hybridizing populations in the upper Kootenay River, southeastern British Columbia, Canada. Using four diagnostic nuclear loci we calculated a hybrid index, inbreeding coefficient, FIS, and the linkage disquilibrium correlation coefficient, Rij, for each locality to determine the distribution of genotypes in each population. We also categorized the 142 hybrid individuals found across localities into four hybrid classes based on their genotypes. The majority of localities (11/18) showed a unimodal distribution of genotypes skewed towards genotypes of WCT. Two localities, however (lower Gold Creek and Lodgepole Creek) showed a flat to bimodal distribution and one site (lower Bull River) showed a unimodal distribution skewed towards RBT genotypes. The majority of hybrid individuals were classified genotypically as WCT backcrosses (59%) and post-F1 individuals (24%). We found a skewed ratio of pure WCT to pure RBT (17:1) and only four F1 hybrids (3%), suggesting that the spread of RBT alleles may be facilitated by hybrids straying to neighbouring populations. We also tested for the action of selection in one population using cohort analyses, but found little evidence of differential selection between pure WCT and hybrid individuals. Pooled across age classes there were significant differences in genotypic frequencies among loci suggesting differential introgression. There was no asymmetry to the hybridization between rainbow trout and westslope cutthroat trout because both species' mitochondrial DNA haplotypes were

  17. New treatment options for irritable bowel syndrome with predominant diarrhea.

    PubMed

    Weber, H Christian

    2017-02-01

    Irritable bowel syndrome (IBS) is a highly prevalent gastrointestinal disorder with negative impact on quality of life and it represents a substantial economic burden on healthcare cost. The medical management of IBS remains largely symptomatic. This review provides an update related to the most recently published diagnostic Rome IV criteria for IBS and clinical trial data for novel treatment modalities in IBS targeting the peripheral opioid receptors of the enteric nervous system and the gut microbiota. The new Rome IV criteria define functional gastrointestinal disorders as disorders of the gut-brain interaction. In addition to previously introduced pharmacological treatment modalities for IBS with constipation (IBS-C) with synthetic peptides and small molecules targeting gastrointestinal receptors and ion channels, the newly Food and Drug Administration-approved mixed peripheral opioid receptor agonist/antagonist eluxadoline and the nonabsorbable antibiotic rifaximin demonstrate efficacy and safety in the treatment of IBS with predominant diarrhea (IBS-D). Diagnostic criteria for functional gastrointestinal disorders, including IBS, have been revised in Rome IV and are defined as gut-brain disorders. The mixed peripheral opioid receptor agonist/antagonist eluxadoline and the antibiotic rifaximin have been recently Food and Drug Administration approved for the treatment of diarrhea-predominant IBS (IBS-D) with proven efficacy and acceptable side-effect profiles.

  18. A global assessment of the male predominance in esophageal adenocarcinoma

    PubMed Central

    Xie, Shao-Hua; Lagergren, Jesper

    2016-01-01

    Background Esophageal adenocarcinoma (EAC) is characterized by a male predominance. However, variations in the sex difference across populations and over time have not previously been thoroughly investigated. Results The male-to-female ratio in EAC incidence varied greatly across continents, ranging from 1.03 in Africa to 7.64 in Northern America during 2003– 2007. The ratio was high in Europe (6.04) and Oceania (6.24), and lower in Asia (4.37) and Latin America and the Caribbean (3.94). The sex ratio remained relatively stable over time in most populations. In absolute terms, the sex difference in EAC incidence increased over time in populations of higher incidence, while it remained stable or slightly decreased in low-incidence populations. Materials and Methods We used data from the Cancer Incidence in Five Continents series to compute sex-specific age-standardized rates of EAC by population. The sex difference in incidence was evaluated on both absolute and relative scales, measured by the absolute difference and ratio between sexes, respectively. Conclusions This first global assessment of the sex ratio in EAC shows that the male predominance is particularly strong in developed countries. The underlying reasons remain to be identified, but the emerging EAC burden in men merits consideration for targeted prevention and early detection. PMID:27145283

  19. Breast cancer in Iraq is associated with a unimodally distributed predominance of luminal type B over luminal type A surrogates from young to old age.

    PubMed

    Majid, Runnak A; Hassan, Hemin A; Muhealdeen, Dana N; Mohammed, Hazha A; Hughson, Michael D

    2017-04-07

    Breast cancer has recently increased in post-menopausal Iraqi women. In Western countries at high-risk for breast cancer, there is a bimodal increase in estrogen receptor (ER) positive tumors with a peak of low proliferation rate luminal A over higher proliferation rate luminal B tumors after 60 years of age. The aim of this study was to analyze in Iraqi women whether shifts are occurring in immunohistochemical (IHC) surrogates of molecular breast cancer subtypes toward a high-risk profile. Age specific and age standardized womens breast cancer incidence was estimated for the years 2006 through 2012. IHC results of ER, PR, HER2, and Ki67 testing were analyzed on the breast cancers of 125 Arabic and 725 Kurdish women by frequency of distribution and by age. Between 2006 and 2012, age standardized incidence of breast cancer in Iraq increased from 30 to 40/100,000 women with the increase specifically occurring in women ≥ 60 years old (P < 0.001). Breast cancers in Kurdish women ≥ 60 years old may also have increased (P = 0.047) with urban exceeding rural rates by 2:1. For both Kurdish and Arabic women, there was a marked predominance of luminal B tumors at all ages in which luminal B and luminal A tumors were asymmetric skewed toward older age but with no late luminal A age peak. Older Iraqi women do not show the bimodal shift toward higher rates of luminal A breast cancers seen in the West. The modest increase in age standardized incidence of breast cancer in Iraqi is being seen specifically in older women and may be better attributed to a trend for care in urban cancer centers rather than changing tumor characteristics.

  20. Origin of silicic crust by rifting and bimodal plume volcanism in the Afar Depression

    NASA Astrophysics Data System (ADS)

    Ghatak, A.; Basu, A. R.; Ebinger, C. J.

    2010-12-01

    The youngest mantle plume province worldwide occurs at the seismically and volcanically active East African - Red Sea - Gulf of Aden (Afar) triple junction, where one or more upwellings has impinged the thick cratonic lithosphere since ~45 Ma. A spectacular example of magmatism in the Afar depression is seen in the present to < 2 Ma old bimodal fissural mafic and peralkaline silicic eruptions in the ~60 km-long Dabbahu-Manda Hararo (DMH) Rift. In this study we report major, trace elements, and Nd-Sr-Pb isotopes in recent basaltic and silicic rocks originating from the center of the DMH rift segment, exposed along the rift axis and flanks of this segment. The rare earth element (REE) patterns of the silicic rocks and basalts are different in two significant ways: (1) the silicic rocks show a prominent positive Ce-anomaly that is extremely rare in volcanic rocks; and (2) this positive Ce-anomaly is accompanied by a strong negative Eu-anomaly. These anomalies are absent in the basaltic rocks. The positive Ce-anomaly is probably due to interaction in a magma chamber, similar in composition to the basalts, with deep saline aquifer or brines that typically show positive Ce-anomaly. The REE patterns of the two lava groups are interpreted to be due to fractional crystallization of plagioclase in a magma chamber similar in REE composition as the basalts that erupted in the DMH segments. We interpret the silicic rocks to be residues after ~20% fractional crystallization of plagioclase in the DMH basalts. The Nd-Pb isotopic composition of the basalts and rhyolites of the DMH are similar to the Ethiopian plume as defined by the ~30 Ma old Ethiopian flood basalts. Based on their high 3He/4He ratios (R/RA ~30) and Nd-Sr-Pb isotopic data, the source of the Ethiopian plume is generally believed to be in the lower mantle. Therefore, the similarity of the Nd-Pb and Pb-Pb isotopic variations between the Ethiopian plume and the DMH lavas indicates that these lavas were sourced from

  1. Predominantly nighttime feeding and weight outcomes in infants.

    PubMed

    Cheng, Tuck Seng; Loy, See Ling; Toh, Jia Ying; Cheung, Yin Bun; Chan, Jerry Kok Yen; Godfrey, Keith M; Gluckman, Peter D; Saw, Seang Mei; Chong, Yap-Seng; Lee, Yung Seng; Lek, Ngee; Chong, Mary Foong-Fong; Yap, Fabian

    2016-08-01

    The influence of circadian feeding patterns on weight outcomes has been shown in animal and human studies but not in very young children. We aimed to examine the association of infant circadian feeding patterns at 12 mo of age with subsequent growth and weight status after 1 y. Mothers from a Singapore birth cohort (n = 349) reported the food given to their infants and the feeding time at 12 mo of age. Predominantly daytime (pDT) (0700-1859; n = 282) and predominantly nighttime (pNT) (1900-0659; n = 67) feeding infants were defined by whether daytime energy intake was >50% or <50% of total energy intake as assessed with the use of a 24-h recall. Body mass index-for-age z scores (BAZs) were computed with the use of the WHO Child Growth Standards 2006 to determine changes in BAZs from 12 to 24 mo of age and weight status at 24 mo of age. Multivariable linear and logistic regression analyses were performed. Compared with pDT feeding, pNT feeding was associated with a higher BAZ gain from 12 to 24 mo of age (adjusted β = 0.38; 95% CI: 0.11, 0.65; P = 0.006) and increased risk of becoming overweight at 24 mo of age (adjusted OR: 2.78; 95% CI: 1.11, 6.97; P = 0.029) with adjustments for maternal age, education, ethnicity, monthly household income, parity, infant BAZ at 12 mo of age, feeding mode in the first 6 mo of life, and total daily energy intake. Our study suggests that the role of the daily distribution of energy consumption in weight regulation begins in infancy. The feeding of infants predominantly during nighttime hours was associated with adiposity gain and risk of overweight in early childhood. The inclusion of advice on the appropriate feeding time may be considered when implementing strategies to combat childhood obesity. This trial was registered at clinicaltrials.gov as NCT01174875. © 2016 American Society for Nutrition.

  2. Can Sulfur Explain the Bimodal Color Distribution Observed in the Jupiter Trojans?

    NASA Astrophysics Data System (ADS)

    Blacksberg, Jordana; Mahjoub, Ahmed; Poston, Michael; Brown, Michael E.; Eiler, John; Ehlmann, Bethany; Hodyss, Robert; Hand, Kevin P.; Carlson, Robert W.; Wong, Ian

    2016-10-01

    We present a series of experiments aimed at exploring the hypothesis that the presence or absence of H2S ice on the surface of primitive icy bodies in the early solar system is responsible for the bimodal color distribution of the Jupiter Trojans.Central to our proposed hypothesis is a location-dependent sublimation of ices in the primordial trans-neptunian disk which would have divided objects according to whether they retained H2S on their surfaces for sufficient time to incorporate their constituents into irradiated organic crusts. The irradiated crusts of objects with and without H2S would have different chemistry and therefore different optical properties. Dynamical instability models of the early solar system (e.g. Morbidelli et al., 2005, Nesvorny et al., 2013) predict that Trojans, formed from this primordial population, were later emplaced inward to co-orbit with Jupiter during large-scale rearrangement events. According to our hypothesis, the Trojans today would show evidence of their primordial location with respect to the H2S sublimation line in the form of a bimodal distribution in surface chemistry, and thus color.We present laboratory spectroscopy experiments in support of this hypothesis. Numerous thin ice films composed of H2O, CH3OH, NH3, were produced both with and without H2S. Subsequent processing of these icy bodies was simulated using electron irradiation and heating. Visible reflectance spectra show significant reddening when H2S is present. Mid-infrared spectra confirm the formation of non-volatile sulfur-containing molecules in the products of H2S-containing ices. The infrared spectral properties of the organic residues remaining at room temperature show that sulfur significantly changes the chemistry of these irradiation-produced organics. These experiments suggest that the presence of specific sulfur-bearing chemical species may play an important role in the colors of both the KBOs and Trojans today. This testable hypothesis could feed

  3. Finite-thrust optimization of interplanetary transfers of space vehicle with bimodal nuclear thermal propulsion

    NASA Astrophysics Data System (ADS)

    Kharytonov, Oleksii M.; Kiforenko, Boris M.

    2011-08-01

    The nuclear thermal rocket (NTR) propulsion is one of the leading promising technologies for primary space propulsion for manned exploration of the solar system due to its high specific impulse capability and sufficiently high thrust-to-weight ratio. Another benefit of NTR is its possible bimodal design, when nuclear reactor is used for generation of a jet thrust in a high-thrust mode and (with an appropriate power conversion system) as a source of electric power to supply the payload and the electric engines in a low-thrust mode. The model of the NTR thrust control was developed considering high-thrust NTR as a propulsion system of limited power and exhaust velocity. For the proposed model the control of the thrust value is accomplished by the regulation of reactor thermal power and propellant mass flow rate. The problem of joint optimization of the combination of high- and low-thrust arcs and the parameters of bimodal NTR (BNTR) propulsion system is considered for the interplanetary transfers. The interplanetary trajectory of the space vehicle is formed by the high-thrust NTR burns, which define planet-centric maneuvers and by the low-thrust heliocentric arcs where the nuclear electric propulsion (NEP) is used. The high-thrust arcs are analyzed using finite-thrust approach. The motion of the corresponding dynamical system is realized in three phase spaces concerning the departure planet-centric maneuver by means of high-thrust NTR propulsion, the low-thrust NEP heliocentric maneuver and the approach high-thrust NTR planet-centric maneuver. The phase coordinates are related at the time instants of the change of the phase spaces due to the relations between the space vehicle masses. The optimal control analysis is performed using Pontryagin's maximum principle. The numerical results are analyzed for Earth-Mars "sprint" transfer. The optimal values of the parameters that define the masses of NTR and NEP subsystems have been evaluated. It is shown that the low

  4. A Retrospective Multicenter Study Comparing Speech Perception Outcomes for Bilateral Implantation and Bimodal Rehabilitation.

    PubMed

    Blamey, Peter J; Maat, Bert; Başkent, Deniz; Mawman, Deborah; Burke, Elaine; Dillier, Norbert; Beynon, Andy; Kleine-Punte, Andrea; Govaerts, Paul J; Skarzynski, Piotr H; Huber, Alexander M; Sterkers-Artières, Françoise; Van de Heyning, Paul; O'Leary, Stephen; Fraysse, Bernard; Green, Kevin; Sterkers, Olivier; Venail, Frédéric; Skarzynski, Henryk; Vincent, Christophe; Truy, Eric; Dowell, Richard; Bergeron, François; Lazard, Diane S

    2015-01-01

    To compare speech perception outcomes between bilateral implantation (cochlear implants [CIs]) and bimodal rehabilitation (one CI on one side plus one hearing aid [HA] on the other side) and to explore the clinical factors that may cause asymmetric performances in speech intelligibility between the two ears in case of bilateral implantation. Retrospective data from 2247 patients implanted since 2003 in 15 international centers were collected. Intelligibility scores, measured in quiet and in noise, were converted into percentile ranks to remove differences between centers. The influence of the listening mode among three independent groups, one CI alone (n = 1572), bimodal listening (CI/HA, n = 589), and bilateral CIs (CI/CI, n = 86), was compared in an analysis taking into account the influence of other factors such as duration of profound hearing loss, age, etiology, and duration of CI experience. No within-subject comparison (i.e., monitoring outcome modifications in CI/HA subjects becoming CI/CI) was possible from this dataset. Further analyses were conducted on the CI/CI subgroup to investigate a number of factors, such as implantation side, duration of hearing loss, amount of residual hearing, and use of HAs that may explain asymmetric performances of this subgroup. Intelligibility ranked scores in quiet and in noise were significantly greater with both CI/CI and CI/HA than with a CI-alone group, and improvement with CI/CI (+11% and +16% in quiet and in noise, respectively) was significantly better than with CI/HA (+6% and +9% in quiet and in noise, respectively). From the CI/HA group, only subjects with ranked preoperative aided speech scores >60% performed as well as CI/CI participants. Furthermore, CI/CI subjects displayed significantly lower preoperative aided speech scores on average compared with that displayed by CI/HA subjects. Routine clinical data available from the present database did not explain the asymmetrical results of bilateral implantation

  5. Diverse Kir Expression Contributes to Distinct Bimodal Distribution of Resting Potentials and Vasotone Responses of Arterioles

    PubMed Central

    Yang, Yuqin; Chen, Fangyi; Karasawa, Takatoshi; Ma, Ke-Tao; Guan, Bing-Cai; Shi, Xiao-Rui; Li, Hongzhe; Steyger, Peter S.; Nuttall, Alfred L.; Jiang, Zhi-Gen

    2015-01-01

    The resting membrane potential (RP) of vascular smooth muscle cells (VSMCs) is a major determinant of cytosolic calcium concentration and vascular tone. The heterogeneity of RPs and its underlying mechanism among different vascular beds remain poorly understood. We compared the RPs and vasomotion properties between the guinea pig spiral modiolar artery (SMA), brain arterioles (BA) and mesenteric arteries (MA). We found: 1) RPs showed a robust bimodal distribution peaked at -76 and -40 mV evenly in the SMA, unevenly at -77 and -51 mV in the BA and ~-71 and -52 mV in the MA. Ba2+ 0.1 mM eliminated their high RP peaks ~-75 mV. 2) Cells with low RP (~-45 mV) hyperpolarized in response to 10 mM extracellular K+, while cells with a high RP depolarized, and cells with intermediate RP (~-58 mV) displayed an initial hyperpolarization followed by prolonged depolarization. Moderate high K+ typically induced dilation, constriction and a dilation followed by constriction in the SMA, MA and BA, respectively. 3) Boltzmann-fit analysis of the Ba2+-sensitive inward rectifier K+ (Kir) whole-cell current showed that the maximum Kir conductance density significantly differed among the vessels, and the half-activation voltage was significantly more negative in the MA. 4) Corresponding to the whole-cell data, computational modeling simulated the three RP distribution patterns and the dynamics of RP changes obtained experimentally, including the regenerative swift shifts between the two RP levels after reaching a threshold. 5) Molecular works revealed strong Kir2.1 and Kir2.2 transcripts and Kir2.1 immunolabeling in all 3 vessels, while Kir2.3 and Kir2.4 transcript levels varied. We conclude that a dense expression of functional Kir2.X channels underlies the more negative RPs in endothelial cells and a subset of VSMC in these arterioles, and the heterogeneous Kir function is primarily responsible for the distinct bimodal RPs among these arterioles. The fast Kir-based regenerative shifts

  6. Design and Development of the MITEE-B Bi-Modal Nuclear Propulsion Engine

    NASA Astrophysics Data System (ADS)

    Paniagua, John C.; Powell, James R.; Maise, George

    2003-01-01

    Previous studies of compact, ultra-lightweight high performance nuclear thermal propulsion engines have concentrated on systems that only deliver high thrust. However, many potential missions also require substantial amounts of electric power. Studies of a new, very compact and lightweight bi-modal nuclear engine that provides both high propulsive thrust and high electric power for planetary science missions are described. The design is a modification of the MITEE nuclear thermal engine concept that provided only high propulsive thrust. In the new design, MITEE-B, separate closed cooling circuits are incorporated into the reactor, which transfers useful amounts of thermal energy to a small power conversion system that generates continuous electric power over the full life of the mission, even when the engine is not delivering propulsive thrust. Two versions of the MITEE-B design are described and analyzed. Version 1 generates 1 kW(e) of continuous power for control of the spacecraft, sensors, data transmission, etc. This power level eliminates the need for RTG's on missions to the outer planets, and allowing considerably greater operational capability for the spacecraft. This, plus its high thrust and high specific impulse propulsive capabilities, makes MITEE-B very attractive for such missions. In Version 2, of MITEE-B, a total of 20 kW(e) is generated, enabling the use of electric propulsion. The combination of high open cycle propulsion thrust (20,000 Newtons) with a specific impulse of ~1000 seconds for short impulse burns, and long term (months to years), electric propulsion greatly increases MITEE's ΔV capability. Version 2 of MITEE-B also enables the production and replenishment of H2 propellant using in-situ resources, such as electrolysis of water from the ice sheet on Europa and other Jovian moons. This capability would greatly increase the ΔV available for certain planetary science missions. The modifications to the MITEE multiple pressure tube

  7. [Pancreatitis predominantly affecting the caudal part of the pancreas].

    PubMed

    Filin, V I; Krasnorogov, V B; Makhovich, I S; Zaĭtsev, E I; Tolstoĭ, A D

    1989-03-01

    The characteristics of specific features of acute and chronic processes in the caudal pancreatis and surrounding retroperitoneal fat is given on the basis of an analysis of 273 cases of pancreatitis with the predominant lesion of this portion. It was established that acute caudal pancreonecrosis at an early period had atypical symptoms and more favourable course than that of the proximal parts of the pancreas. Later periods of the development of this variant of the disease are characterized by great frequency and spread of pyo-necrotic lesion of the retroperitoneal fat. Specific features of the clinical course, diagnosis and treatment were formulated and their being taken into account allowed to reduce lethality of patients with caudal pancreatitis from 39.0% to 25.0%.

  8. [Rotator cuff ruptures with predominant involvement of the subscapular tendon].

    PubMed

    Nérot, C; Jully, J L; Gérard, Y

    Among the all rotator cuff tears, the subscapularis lesions are quite rare. But a careful analysis leads to recognize them specially in case of antero-medial impingement between the coracoid process and the head of the humerus. This study of 25 observations where the rupture of the subscapularis was the predominant lesion, allows to emphasize some characteristics of them. The patients are often younger than for the other ruptures, a traumatic experience is not rare at the beginning of the history, the pain is usually the first symptom before the functional disability, the alterations of the rotator-interval and of the biceps tendon are very frequent, the arthroscanner is a very good help for the diagnosis and satisfying stitches are possible in case of early diagnoses. Lastly, the prognosis of these limited lesions is quite different than the one of very large cuff tears including the suscapularis tendon.

  9. Nodular Lymphocyte Predominant Hodgkin Lymphoma of the Thyroid

    PubMed Central

    Cassis, João; Simões, Helder; Sequeira Duarte, João

    2016-01-01

    Thyroid lymphomas are rare clinical entities that may result from either the primary intrathyroid de novo or secondary thyroid gland involvement of a lymphoma. Among these, the Hodgkin's subtype is quite uncommon, accounting for 0.6–5% of all thyroid malignancies. The authors report on a 76-year-old female presenting with a thyroid nodule that, upon surgical excision, was found to be a nodular lymphocyte predominant Hodgkin lymphoma of the thyroid. So far, thyroid involvement by this variant has never been reported. Upon reporting on this clinical case, the authors emphasize the difficulties usually found in establishing the diagnosis and in defining the best management strategy. A thorough review of the available literature is done. PMID:28044111

  10. Birefringent Stable Glass with Predominantly Isotropic Molecular Orientation

    NASA Astrophysics Data System (ADS)

    Liu, Tianyi; Exarhos, Annemarie L.; Alguire, Ethan C.; Gao, Feng; Salami-Ranjbaran, Elmira; Cheng, Kevin; Jia, Tiezheng; Subotnik, Joseph E.; Walsh, Patrick J.; Kikkawa, James M.; Fakhraai, Zahra

    2017-09-01

    Birefringence in stable glasses produced by physical vapor deposition often implies molecular alignment similar to liquid crystals. As such, it remains unclear whether these glasses share the same energy landscape as liquid-quenched glasses that have been aged for millions of years. Here, we produce stable glasses of 9-(3,5-di(naphthalen-1-yl)phenyl)anthracene molecules that retain three-dimensional shapes and do not preferentially align in a specific direction. Using a combination of angle- and polarization-dependent photoluminescence and ellipsometry experiments, we show that these stable glasses possess a predominantly isotropic molecular orientation while being optically birefringent. The intrinsic birefringence strongly correlates with increased density, showing that molecular ordering is not required to produce stable glasses or optical birefringence, and provides important insights into the process of stable glass formation via surface-mediated equilibration. To our knowledge, such novel amorphous packing has never been reported in the past.

  11. Nodular lymphocyte predominant hodgkin lymphoma: biology, diagnosis and treatment.

    PubMed

    Goel, Anupama; Fan, Wen; Patel, Amit A; Devabhaktuni, Madhuri; Grossbard, Michael L

    2014-08-01

    Nodular lymphocyte predominant Hodgkin lymphoma (NLPHL) is an uncommon variant of classical Hodgkin lymphoma. It is characterized histologically by presence of lymphohistiocytic cells which have B-cell phenotype, are positive for CD19, CD20, CD45, CD79a, BOB.1, Oct.2, and negative for CD15 and CD30. Patients often present with early stage of disease and do not have classical B symptoms. The clinical behavior appears to mimic that of an indolent non-Hodgkin lymphoma more than that of classical Hodgkin disease. The purpose of the present report is to define the biology of NLPHL, review its clinical presentation, and summarize the available clinical data regarding treatment. Copyright © 2014 Elsevier Inc. All rights reserved.

  12. Histological and genetic evidence for a variant of superficial spreading melanoma composed predominantly of large nests.

    PubMed

    Kutzner, Heinz; Metzler, Gisela; Argenyi, Zsolt; Requena, Luis; Palmedo, Gabriele; Mentzel, Thomas; Rütten, Arno; Hantschke, Markus; Paredes, Bruno E; Schärer, Leo; Hesse, Benedikt; El-Shabrawi-Caelen, Laila; Shabrawi-Caelen, Leila El; Fried, Isabella; Kerl, Helmut; Lorenzo, Cerroni; Murali, Rajmohan; Wiesner, Thomas

    2012-06-01

    Cutaneous melanomas are characterized by a range of histological appearances, and several morphological variants have been described. In this study, we report a variant of superficial spreading melanoma that is characterized by large, irregular junctional melanocytic nests. The junctional nests varied in shape and size, showed focal tendency to confluence, and were often surrounded by a cuff of epidermal keratinocytes. The melanocytes comprising the nests showed variable cytological atypia. In most of the cases, scant intraepidermal or junctional single melanocytes were seen, and other well-documented diagnostic criteria for melanoma were lacking, and as a result, histological recognition of these tumors as melanoma was difficult. Some cases were associated with an invasive dermal component or showed evidence of sun damage. To provide supporting evidence for malignancy, we analyzed these tumors for genomic aberrations. Using array comparative genomic hybridization (aCGH), we identified multiple genomic aberrations in all analyzed cases. A similar pattern of genomic aberrations was seen in a control group of bona fide superficial spreading melanomas, suggesting that these 'melanomas composed exclusively or predominantly of large nests' are indeed variants of superficial spreading melanoma. Fluorescence in-situ hybridization (FISH) was positive in 40% of the cases. However, using aCGH, the FISH-negative cases showed multiple genomic aberrations in regions that are not covered by FISH. The low sensitivity of the FISH test can be explained by the fact that FISH only evaluates four genomic loci for aberrations, whereas aCGH surveys the entire genome. In summary, we present histological and molecular genetic evidence for a morphological variant of superficial spreading melanoma. Awareness of the histological features will aid in their correct diagnosis as melanoma, and in difficult cases, judicious application of ancillary tests such as aCGH (rather than FISH) will

  13. Nav1.7 is the predominant sodium channel in rodent olfactory sensory neurons

    PubMed Central

    2011-01-01

    Background Voltage-gated sodium channel Nav1.7 is preferentially expressed in dorsal root ganglion (DRG) and sympathetic neurons within the peripheral nervous system. Homozygous or compound heterozygous loss-of-function mutations in SCN9A, the gene which encodes Nav1.7, cause congenital insensitivity to pain (CIP) accompanied by anosmia. Global knock-out of Nav1.7 in mice is neonatal lethal reportedly from starvation, suggesting anosmia. These findings led us to hypothesize that Nav1.7 is the main sodium channel in the peripheral olfactory sensory neurons (OSN, also known as olfactory receptor neurons). Methods We used multiplex PCR-restriction enzyme polymorphism, in situ hybridization and immunohistochemistry to determine the identity of sodium channels in rodent OSNs. Results We show here that Nav1.7 is the predominant sodium channel transcript, with low abundance of other sodium channel transcripts, in olfactory epithelium from rat and mouse. Our in situ hybridization data show that Nav1.7 transcripts are present in rat OSNs. Immunostaining of Nav1.7 and Nav1.6 channels in rat shows a complementary accumulation pattern with Nav1.7 in peripheral presynaptic OSN axons, and Nav1.6 primarily in postsynaptic cells and their dendrites in the glomeruli of the olfactory bulb within the central nervous system. Conclusions Our data show that Nav1.7 is the dominant sodium channel in rat and mouse OSN, and may explain anosmia in Nav1.7 null mouse and patients with Nav1.7-related CIP. PMID:21569247

  14. Bimodal magmatism of the Tucumã area, Carajás province: U-Pb geochronology, classification and processes

    NASA Astrophysics Data System (ADS)

    Silva, Fernando Fernandes da; Oliveira, Davis Carvalho de; Antonio, Paul Y. J.; D'Agrella Filho, Manoel S.; Lamarão, Claudio Nery

    2016-12-01

    Geological mapping of the Tucumã area has enabled the identification of dike swarms intruded into an Archean basement. The disposition of these dikes is consistent with the well-defined NW-SE trending regional faults, and they can reach up to 20 km in length. They were divided into three main groups: (i) felsic dikes (70% of the dikes), composed exclusively of porphyritic rhyolite with euhedral phenocrysts of quartz and feldspars immersed in an aphyric felsite matrix; (ii) mafic dikes, with restricted occurrence, composed of basaltic andesite and subordinate basalt, with a mineralogical assembly consisting dominantly of plagioclase, clinopyroxene, orthopyroxene and olivine; and (iii) intermediate rocks, represented by andesite and dacite. Dacites are found in outcrops associated with felsic dikes, representing different degrees of hybridization or mixture of mafic and felsic magmas. This is evidenced by a large number of mafic enclaves in the felsic dikes and the frequent presence of embayment textures. SHRIMP U-Pb zircon dating of felsic dikes yielded an age of 1880.9 ± 3.3 Ma. The felsic dikes are peraluminous to slightly metaluminous and akin to A2, ferroan and reduced granites. The intermediate and mafic dikes are metaluminous and belong to the tholeiitic series. Geochemical modeling showed that mafic rocks evolved by pyroxene and plagioclase crystallization, while K-feldspar and biotite are the fractionate phases in felsic magma. A simple binary mixture model was used to determine the origin of intermediate rocks. It indicated that mixing 60% of rhyolite and 40% basaltic andesite melts could have generated the dacitic composition, while the andesite liquid could be produced by mixing of 60% and 40% basaltic andesite and rhyolite melts, respectively. The mixing of basaltic and andesitic magmas probably occurred during ascent and storage in the crust, where andesite dikes are likely produced by a more homogeneous mixture at high depths in the continental crust

  15. Iron deficiency anemia in predominantly breastfed young children.

    PubMed

    Tsai, Shu-Fan; Chen, Shu-Jen; Yen, Hsiu-Ju; Hung, Giun-Yi; Tsao, Pei-Chen; Jeng, Mei-Jy; Lee, Yu-Sheng; Soong, Wen-Jue; Tang, Ren-Bin

    2014-12-01

    Due to the increase of breastfeeding in infants, iron deficiency anemia (IDA) related to prolonged, predominant breastfeeding should be of concern. Mostly, the manifestation of IDA is indistinguishable and the enthusiastic advocacy of breastfeeding without concomitant education of complementary food may lead to ignorance of breast milk-related IDA, which may result in impaired psychomotor development of the baby. This retrospective study was conducted to re-emphasize this easily ignored but still prevalent illness. This retrospective study involved 15 breastfeeding babies who were diagnosed with IDA between January 2007 and December 2010 at age 6-18 months. The clinical presentation, age at diagnosis, initial hemoglobin level and mean corpuscular volume, growth percentile, and duration of treatment were recorded and analyzed. None of the babies was suspected to have anemia by caregivers. Pallor was noticed by physicians in nine patients; one patient had seizure, one patient had pica, and, for the remaining four patients, IDA was diagnosed incidentally due to other medical events. Oral iron supplementation for an average of 3.6 months improved both hemoglobin level (from 8.0 g/dL to 11.5 g/dL) and mean corpuscular volume (from 57.5 fL to 73.9 fL). Most babies had appropriate growth and normal neurological development; two babies had both IDA and thalassemia. Although the association of IDA with prolonged, predominant breastfeeding is well known, its presentation is so subtle that its detection relies mainly on alert medical personnel. Copyright © 2014. Published by Elsevier B.V.

  16. Characterization of the Microenvironment of Nodular Lymphocyte Predominant Hodgkin Lymphoma

    PubMed Central

    Visser, Lydia; Wu, Rui; Rutgers, Bea; Diepstra, Arjan; van den Berg, Anke

    2016-01-01

    Nodular lymphocyte predominant Hodgkin lymphoma (NLPHL) is characterized by a low percentage of neoplastic lymphocyte predominant (LP) cells in a background of lymphocytes. The goal of this study is to characterize the microenvironment in NLPHL. Ten NLPHL cases and seven reactive lymph nodes (RLN) were analyzed by flow cytometry for the main immune cells and multiple specific subpopulations. To discriminate between cells in or outside the tumor cell area, we used CD26. We observed significantly lower levels of CD20+ B-cells and CD56+ NK cells and higher levels of CD4+ T-cells in NLPHL in comparison to RLN. In the subpopulations, we observed increased numbers of PD-1+CD4+ T follicular helper cells (TFH), CD69+CD4+ and CD69+CD8+ T-cells and CCR7-CD45RA-CD4+ effector memory T-cells, while FoxP3+CD4+ T regulatory cells (Tregs) and CCR7-CD45RA+ terminally differentiated CD4+ T-cells were decreased in NLPHL compared to RLN. CD69+ cells were increased in the tumor cell area in CD4+ and CD8+ T-cells, while FoxP3+CD25+CD4+ Tregs and CD25+CD8+ T-cells were significantly increased outside the tumor area. Thus, we show a markedly altered microenvironment in NLPHL, with lower numbers of NK cells and Tregs. PD-1+CD4+ and CD69+ T-cells were located inside, and Tregs and CD25+CD8+ cells outside the tumor cell area. PMID:27999289

  17. Spontaneous fission properties of sup 258 Fm, sup 259 Md, sup 260 Md, sup 258 No, and sup 260 (104): Bimodal fission

    SciTech Connect

    Hulet, E.K.; Wild, J.F.; Dougan, R.J.; Lougheed, R.W.; Landrum, J.H.; Dougan, A.D.; Baisden, P.A.; Henderson, C.M.; Dupzyk, R.J. ); Hahn, R.L.; and others

    1989-08-01

    We have measured the mass and kinetic-energy distributions from the spontaneous fission of {sup 258}Fm, {sup 258}No, {sup 259}Md, {sup 260}Md, and {sup 260}(104). All are observed to fission with a symmetrical division of mass. The total-kinetic-energy distributions strongly deviated from the Gaussian shape characteristically found in the fission of all other actinides. When the total-kinetic-energy distributions are resolved into two Gaussians, the constituent peaks lie near 200 and 233 MeV. We conclude that both low- and high-energy fission modes occur in four of the five nuclides studied. We call this property bimodal fission.'' Even though both modes are possible in the same nuclide, one generally predominates. We offer an explanation for each mode based on shell structures of the fissioning nucleus and of its fragments. The appearance of both modes of fission in this region of the nuclide chart seems to be a coincidence in that the opportunity to divide into near doubly magic Sn fragments occurs in the same region where the second fission barrier is expected to drop in energy below the ground state of the fissioning nucleus. Appropriate paths on the potential-energy surface of deformation have been found by theorists, but no physical grounds have been advanced that would allow the near equal populations we observe traveling each path. We suggest that this failure to find a reason for somewhat equal branching may be a fundamental flaw of current fission models. Assuming the proposed origins of these modes are correct, we conclude the low-energy, but also mass-symmetrical mode is likely to extend to far heavier nuclei. The high-energy mode will be restricted to a smaller region, a realm of nuclei defined by the proximity of the fragments to the strong neutron and proton shells in {sup 132}Sn.

  18. A symmetrical fluorous dendron-cyanine dye conjugated bimodal nanoprobe for quantitative 19F MRI and NIR fluorescence bioimaging

    PubMed Central

    Wang, Zhe; Yue, Xuyi; Wang, Yu; Qian, Chunqi; Huang, Peng; Lizak, Marty; Niu, Gang; Wang, Fu; Rong, Pengfei; Kiesewetter, Dale O.; Ma, Ying; Chen, Xiaoyuan

    2014-01-01

    19F MRI and optical imaging are two powerful non-invasive molecular imaging modalities in biomedical applications. 19F MRI has great potential for high resolution in vivo imaging, while fluorescent probes enable ultracontrast cellular/tissue imaging with high accuracy and sensitivity. We, thus, developed a bimodal nanoprobe integrating the merits of 19F MRI and fluorescence imaging into a single synthetic molecule, which was further engineered into nanoprobe, by addressing shortcomings of conventional contrast agents to explore the quantitative 19F MRI and fluorescence imaging and cell tracking. Results showed that this bimodal imaging nanoprobe presented high correlation of 19F MR signal and NIR fluorescence intensity in vitro and in vivo. Additionally, this nanoprobe enabled quantitative 19F MR analysis, confirmed by complementary fluorescence analysis. This unique feature can hardly be obtained by traditional 19F MRI contrast agents. We envision that this nanoprobe would hold great potential for quantitative and sensitive multi-modal molecular imaging. PMID:24789108

  19. Texture Evaluation of a Bi-Modal Structure During Static Recrystallization of Hot-Deformed Mg-Al-Sn Alloy

    NASA Astrophysics Data System (ADS)

    Kabir, Abu Syed Humaun; Su, Jing; Yue, Stephen

    2016-12-01

    In this study, Mg-Al-Sn alloy was hot compressed at 523 K (250 °C) and annealed at 623 K (350 °C) for various times. The initial as-deformed microstructure was partially dynamic recrystallized with strain-induced precipitates on the recrystallized grain boundaries. After annealing at 623 K (350 °C), static recrystallization (SRX) of the bimodal microstructure took place where, at this temperature, no static precipitates formed. The goal of this work was to study the effect of dynamic precipitation on the texture evolution during the SRX process. Progressive texture evolution was studied during annealing by electron backscattered diffraction technique through a microstructure-tracking process. It was found that the grain-coarsening mechanism during the early stage of annealing is not totally controlled by the basal-oriented grains. Also, it was found that the dynamic precipitates may have significant influence in the early texture weakening during annealing of a bimodal structure.

  20. Validating a bimodal intravascular ultrasound (IVUS) and near-infrared fluorescence (NIRF) catheter for atherosclerotic plaque detection in rabbits

    PubMed Central

    Abran, Maxime; Stähli, Barbara E.; Merlet, Nolwenn; Mihalache-Avram, Teodora; Mecteau, Mélanie; Rhéaume, Eric; Busseuil, David; Tardif, Jean-Claude; Lesage, Frédéric

    2015-01-01

    Coronary artery disease is characterized by atherosclerotic plaque formation. Despite impressive advances in intravascular imaging modalities, in vivo molecular plaque characterization remains challenging, and different multimodality imaging systems have been proposed. We validated an engineered bimodal intravascular ultrasound imaging (IVUS) / near-infrared fluorescence (NIRF) imaging catheter in vivo using a balloon injury atherosclerosis rabbit model. Rabbit aortas and right iliac arteries were scanned in vivo after indocyanine green (ICG) injection, and compared to corresponding ex vivo fluorescence and white light images. Areas of ICG accumulation were colocalized with macroscopic atherosclerotic plaque formation. In vivo imaging was performed with the bimodal catheter integrating ICG-induced fluorescence signals into cross-sectional IVUS imaging. In vivo ICG accumulation corresponded to ex vivo fluorescence signal intensity and IVUS identified plaques. PMID:26504648

  1. Validating a bimodal intravascular ultrasound (IVUS) and near-infrared fluorescence (NIRF) catheter for atherosclerotic plaque detection in rabbits.

    PubMed

    Abran, Maxime; Stähli, Barbara E; Merlet, Nolwenn; Mihalache-Avram, Teodora; Mecteau, Mélanie; Rhéaume, Eric; Busseuil, David; Tardif, Jean-Claude; Lesage, Frédéric

    2015-10-01

    Coronary artery disease is characterized by atherosclerotic plaque formation. Despite impressive advances in intravascular imaging modalities, in vivo molecular plaque characterization remains challenging, and different multimodality imaging systems have been proposed. We validated an engineered bimodal intravascular ultrasound imaging (IVUS) / near-infrared fluorescence (NIRF) imaging catheter in vivo using a balloon injury atherosclerosis rabbit model. Rabbit aortas and right iliac arteries were scanned in vivo after indocyanine green (ICG) injection, and compared to corresponding ex vivo fluorescence and white light images. Areas of ICG accumulation were colocalized with macroscopic atherosclerotic plaque formation. In vivo imaging was performed with the bimodal catheter integrating ICG-induced fluorescence signals into cross-sectional IVUS imaging. In vivo ICG accumulation corresponded to ex vivo fluorescence signal intensity and IVUS identified plaques.

  2. Preparation and evaluation of polyurethane/cellulose nanowhisker bimodal foam nanocomposites for osteogenic differentiation of hMSCs.

    PubMed

    Shahrousvand, Ehsan; Shahrousvand, Mohsen; Ghollasi, Marzieh; Seyedjafari, Ehsan; Jouibari, Iman Sahebi; Babaei, Amir; Salimi, Ali

    2017-09-01

    Biocompatible and biodegradable polyurethanes (PUs) based on polycaprolactone diol (PCL) were prepared and filled with cellulose nanowhiskers (CNWs) obtained from wastepaper. The incorporated polyurethane nanocomposites were used to prepare foamed scaffolds with bimodal cell sizes through solvent casting/particulate leaching method. Sodium chloride and sugar porogens were also prepared to fabricate the scaffolds. The mechanical and thermal properties of PU/CNW nanocomposites were investigated. Incorporation of different CNWs resulted in various structures with tunable mechanical properties and biodegradability. All bimodal foam nanocomposites were biodegradable and also non-cytotoxic as revealed by MTT assay using SNL fibroblast cell line. PU/CNW foam scaffolds were used for osteogenic differentiation of human mesenchymal stem cells (hMSCs). Based on the results, such PU/CNW nanocomposites could support proliferation and osteogenic differentiation of hMSCs in three-dimensional synthetic extracellular matrix (ECM). Copyright © 2017 Elsevier Ltd. All rights reserved.

  3. Equivalence of coupled networks and networks with multimodal frequency distributions: Conditions for the bimodal and trimodal case

    NASA Astrophysics Data System (ADS)

    Pietras, Bastian; Deschle, Nicolás; Daffertshofer, Andreas

    2016-11-01

    Populations of oscillators can display a variety of synchronization patterns depending on the oscillators' intrinsic coupling and the coupling between them. We consider two coupled symmetric (sub)populations with unimodal frequency distributions. If internal and external coupling strengths are identical, a change of variables transforms the system into a single population of oscillators whose natural frequencies are bimodally distributed. Otherwise an additional bifurcation parameter κ enters the dynamics. By using the Ott-Antonsen ansatz, we rigorously prove that κ does not lead to new bifurcations, but that a symmetric two-coupled-population network and a network with a symmetric bimodal frequency distribution are topologically equivalent. Seeking for generalizations, we further analyze a symmetric trimodal network vis-à-vis three coupled symmetric unimodal populations. Here, however, the equivalence with respect to stability, dynamics, and bifurcations of the two systems no longer holds.

  4. Effect of bimodal harmonic structure design on the deformation behaviour and mechanical properties of Co-Cr-Mo alloy.

    PubMed

    Vajpai, Sanjay Kumar; Sawangrat, Choncharoen; Yamaguchi, Osamu; Ciuca, Octav Paul; Ameyama, Kei

    2016-01-01

    In the present work, Co-Cr-Mo alloy compacts with a unique bimodal microstructural design, harmonic structure design, were successfully prepared via a powder metallurgy route consisting of controlled mechanical milling of pre-alloyed powders followed by spark plasma sintering. The harmonic structured Co-Cr-Mo alloy with bimodal grain size distribution exhibited relatively higher strength together with higher ductility as compared to the coarse-grained specimens. The harmonic Co-Cr-Mo alloy exhibited a very complex deformation behavior wherein it was found that the higher strength and the high retained ductility are derived from fine-grained shell and coarse-grained core regions, respectively. Finally, it was observed that the peculiar spatial/topological arrangement of stronger fine-grained and ductile coarse-grained regions in the harmonic structure promotes uniformity of strain distribution, leading to improved mechanical properties by suppressing the localized plastic deformation during straining.

  5. Annexin A5-Functionalized Bimodal Nanoparticles for MRI and Fluorescence Imaging of Atherosclerotic Plaques

    PubMed Central

    van Tilborg, Geralda A. F.; Vucic, Esad; Strijkers, Gustav J.; Cormode, David P.; Mani, Venkatesh; Skajaa, Torjus; Reutelingsperger, Chris P. M.; Fayad, Zahi A.; Mulder, Willem J. M.; Nicolay, Klaas

    2011-01-01

    Apoptosis and macrophage burden are believed to correlate with atherosclerotic plaque vulnerability and are therefore considered important diagnostic and therapeutic targets for atherosclerosis. These cell types are characterized by the exposure of phosphatidylserine (PS) at their surface. In the present study, we developed and applied a small micellar fluorescent annexin A5-functionalized nanoparticle for noninvasive magnetic resonance imaging (MRI) of PS exposing cells in atherosclerotic lesions. Annexin A5-mediated target-specificity was confirmed with ellipsometry and in vitro binding to apoptotic Jurkat cells. In vivo T1-weighted MRI of the abdominal aorta in atherosclerotic ApoE−/− mice revealed enhanced uptake of the annexin A5-micelles as compared to control-micelles, which was corroborated with ex vivo near-infrared fluorescence images of excised whole aortas. Confocal laser scanning microscopy (CLSM) demonstrated that the targeted agent was associated with macrophages and apoptotic cells, whereas the nonspecific control agent showed no clear uptake by such cells. In conclusion, the annexin A5-conjugated bimodal micelles displayed potential for noninvasive assessment of cell types that are considered to significantly contribute to plaque instability and therefore may be of great value in the assessment of atherosclerotic lesion phenotype. PMID:20804153

  6. [An analysis of code-switching phenomenon in bimodal bilinguals (Libras and Portuguese).

    PubMed

    de Sousa, Aline Nunes; de Quadros, Ronice Müller

    2012-01-01

    An interesting linguistic phenomenon that happens in the interaction among bilingual people is code-switching. In this paper, we are investigating code-switching among oral Brazilian Portuguese and Brazilian Sign Language - Libras, in a same enunciative chain, with the goal of identifying and analyzing the use of code-switching in the speech of a child and an adult (both hearing from deaf parents), interacting in an intermodal bilingual context, with deaf and hearing interlocutors. Code-switching in languages, in this case, occurs when a person stops to speak in Portuguese and he/she alternates to sign. This present research is a starting study, with qualitative analysis of data. Our corpus is composed of nine sections of interactions in Libras and oral Portuguese, recorded in video, part of the Bimodal Bilingual Development Project from UFSC. The data shows that adult and child's characteristics of code-switching seem to have similarities and differences. The adult seems to switch more worried about the course of the interaction. On the other hand, the child did not seem to use code-switching for specific pragmatic reasons. In regard to the switching extension, it is noted that both the child and the adult used more than one word sentences. The role of the interlocutors seems to be decisive in the interactions investigated here - especially for the adult, since the child is still acquiring awareness about the role of the interlocutor in an interaction.

  7. Phase mapping of ultrashort pulses in bimodal photonic structures: A window on local group velocity dispersion

    NASA Astrophysics Data System (ADS)

    Gersen, H.; van Dijk, E. M. H. P.; Korterik, J. P.; van Hulst, N. F.; Kuipers, L.

    2004-12-01

    The amplitude and phase evolution of ultrashort pulses in a bimodal waveguide structure has been studied with a time-resolved photon scanning tunneling microscope (PSTM). When waveguide modes overlap in time intriguing phase patterns are observed. Phase singularities, arising from interference between different modes, are normally expected at equidistant intervals determined by the difference in effective index for the two modes. However, in the pulsed experiments the distance between individual singularities is found to change not only within one measurement frame, but even depends strongly on the reference time. To understand this observation it is necessary to take into account that the actual pulses generating the interference signal change shape upon propagation through a dispersive medium. This implies that the spatial distribution of phase singularities contains direct information on local dispersion characteristics. At the same time also the mode profiles, wave vectors, pulse lengths, and group velocities of all excited modes in the waveguide are directly measured. The combination of these parameters with an analytical model for the time-resolved PSTM measurements shows that the unique spatial phase information indeed gives a direct measure for the group velocity dispersion of individual modes. As a result interesting and useful effects, such as pulse compression, pulse spreading, and pulse reshaping become accessible in a local measurement.

  8. Phase mapping of ultrashort pulses in bimodal photonic structures: a window on local group velocity dispersion.

    PubMed

    Gersen, H; van Dijk, E M H P; Korterik, J P; van Hulst, N F; Kuipers, L

    2004-12-01

    The amplitude and phase evolution of ultrashort pulses in a bimodal waveguide structure has been studied with a time-resolved photon scanning tunneling microscope (PSTM). When waveguide modes overlap in time intriguing phase patterns are observed. Phase singularities, arising from interference between different modes, are normally expected at equidistant intervals determined by the difference in effective index for the two modes. However, in the pulsed experiments the distance between individual singularities is found to change not only within one measurement frame, but even depends strongly on the reference time. To understand this observation it is necessary to take into account that the actual pulses generating the interference signal change shape upon propagation through a dispersive medium. This implies that the spatial distribution of phase singularities contains direct information on local dispersion characteristics. At the same time also the mode profiles, wave vectors, pulse lengths, and group velocities of all excited modes in the waveguide are directly measured. The combination of these parameters with an analytical model for the time-resolved PSTM measurements shows that the unique spatial phase information indeed gives a direct measure for the group velocity dispersion of individual modes. As a result interesting and useful effects, such as pulse compression, pulse spreading, and pulse reshaping become accessible in a local measurement.

  9. Bi-modal water transport behavior across a simple Nafion membrane

    NASA Astrophysics Data System (ADS)

    Zhang, Ziheng; Promislow, Keith; Martin, Jonathan; Wang, Haijiang; Balcom, Bruce J.

    2011-10-01

    The development of predictive mathematical models for water management in polymer electrolyte membrane fuel cells requires detailed understanding of water distribution and water transport across the Nafion layer. The anisotropic microstructure of Nafion suggests the measurement of water content and mass transport should be along the fuel cell functional direction, i.e. across the membrane. Non-invasive, high resolution, microscopy measurements of this type are very challenging. We report here the calibration of a minimal mathematical model for diffusive water transport in Nafion against data from high-resolution water content maps determined with a new magnetic resonance imaging methodology developed for this purpose. A mock fuel cell was designed to permit well-controlled wetting and drying boundary conditions. With no chemical potential driving force involved, we assume the water transport behavior will be dominated by diffusion. Moreover we show that, in this context, our model is mathematically equivalent to the traditional permeation models based upon saturation dependent pressure gradients via a capillary pressure ansatz. The non-linear equilibrium water distribution across the Nafion membrane measured in this work suggests a bi-modal diffusivity. The model constructed associates distinct transport behaviors to water contents above and below a critical threshold, consistent with a rearrangement of a micro-structural pore network. The experimental observation and the model prediction agree with the primary features of Weber's model of Nafion, which predicts distinct modes of transport for hydration fronts traversing the through-plane direction of the membrane.

  10. Bimodal distribution and fluorescence response of environment-sensitive probes in lipid bilayers.

    PubMed

    Klymchenko, Andrey S; Duportail, Guy; Demchenko, Alexander P; Mély, Yves

    2004-05-01

    A remarkable heterogeneity is often observed in the spectroscopic properties of environment-sensitive fluorescence probes in phospholipid bilayers. To explain its origin, we provided a detailed investigation of the fluorescence excitation and emission spectra of 4'-dimethylamino-3-hydroxyflavone (probe F) in bilayer vesicles with the variations of fatty acid composition, polar heads, temperature, and cholesterol content. Probe F, due to excited-state intramolecular proton transfer, exhibits two bands in emission that are differently sensitive to intermolecular interactions-thereby allowing us to distinguish universal (dipole-dipole) and specific (H-bonding) interactions within the bilayer. Spectroscopic, quenching, and anisotropy data suggest the presence of two forms of probe F at different locations in the bilayer: an H-bond free form located below sn(1)-carbonyls and an H-bonded form located at the polar membrane interface. We provide a quantitative analysis of the distribution of the probe between these two locations as well as the polarity of these locations, and show that both the distribution and the polarity contribute to the probe response. Moreover, analysis of literature data on other environment-sensitive probes (Prodan, Laurdan, Nile Red, NBD lipids, etc.) in lipid bilayers allows us to suggest that the bimodal distribution in the lipid bilayer is probably a general feature of low-polar molecules with polar groups capable of H-bonding interactions.

  11. Represent and fuse bimodal biometric images at the feature level: complex-matrix-based fusion scheme

    NASA Astrophysics Data System (ADS)

    Xu, Yong; Zhang, David

    2010-03-01

    Multibiometrics can obtain a higher accuracy than the single biometrics by simultaneously using multiple biometric traits of the subject. We note that biometric traits are usually in the form of images. Thus, how to properly fuse the information of multiple biometric images of the subject for authentication is crucial for multibiometrics. We propose a novel image-based linear discriminant analysis (IBLDA) approach to fuse two biometric traits (i.e., bimodal biometric images) of the same subject in the form of matrix at the feature level. IBLDA first integrates two biometric traits of one subject into a complex matrix and then directly extracts low-dimensional features for the integrated biometric traits. IBLDA also enables more information to be exploited than the matching score level fusion and the decision level fusion. Compared to linear discriminant analysis (LDA), IBLDA has the following advantages: First, it can overcome the small sample size problem that conventional LDA usually suffers from. Second, IBLDA solves the eigenequation at a low computational cost. Third, when storing the scatter matrices IBLDA will not bring as heavy a memory burden as conventional LDA. We also clearly show the theoretical foundation of the proposed method. The experiment result shows that the proposed method can obtain a high classification accuracy.

  12. Threshold response and bimodality in non-cooperative auto-activation circuits

    NASA Astrophysics Data System (ADS)

    Hermsen, Rutger; Erickson, David; Hwa, Terence

    2011-03-01

    In prokaryotes as well as in eukaryotes, many transcription factors (TFs) activate their own gene. For that reason the benefits of auto-activation have been studied extensively. However, little attention is paid to the fact that many TFs are modified by a signal, usually through phosphorylation or binding of a ligand. Typically only one version of the TF---the modified or the unmodified one---can activate transcription. Consequently the TF's expression level responds to changes in the signal. Here, we use stochastic models to study the response properties of such circuits. In real examples the auto-activation is often mediated by a single binding site. Surprisingly, in that case we find that an arbitrarily sensitive threshold response can be obtained, while the bistability and hysteresis associated with multiple cooperative binding sites are avoided. Also, we find that the steady-state probability distributions of the TF expression level can be bimodal even though the system is not bistable. This is not caused by slow TF--DNA binding kinetics or bursty protein production, as in earlier studies, but by strongly reduced production and degradation rates at low expression levels. This work was supported by the CTBP sponsored by the NSF (Grant PHY-0822283).

  13. Parallel and serial processes in the human oculomotor system: bimodal integration and express saccades.

    PubMed

    Nozawa, G; Reuter-Lorenz, P A; Hughes, H C

    1994-01-01

    Saccadic reaction times (SRTs) were analyzed in the context of stochastic models of information processing (e.g., Townsend and Ashby 1983) to reveal the processing architecture(s) underlying integrative interactions between visual and auditory inputs and the mechanisms of express saccades. The results support the following conclusions. Bimodal (visual+auditory) targets are processed in parallel, and facilitate SRT to an extent that exceeds levels attainable by probability summation. This strongly implies neural summation between elements responding to spatially aligned visual and auditory inputs in the human oculomotor system. Second, express saccades are produced within a separable processing stage that is organized in series with that responsible for intersensory integration. A model is developed that implements this combination of parallel and serial processing. The activity in parallel input channels is summed within a sensory stage which is organized in series with a pre-motor and motor stage. The time course of each subprocess is considered a random variable, and different experimental manipulations can selectively influence different stages. Parallels between the model and physiological data are explored.

  14. Ethylcellulose nanoparticles with bimodal size distribution as precursors for the production of very small nanoparticles.

    PubMed

    Wachsmann, Philip; Lamprecht, Alf

    2015-01-01

    A common technique for the preparation of polymeric nanoparticles (NPs) from preformed polymers is the emulsification solvent evaporation (ESE) method. However, the particle size of such carriers can typically not reduced below 100 nm. A bimodal distribution of particle size when applying ESE to the preparation of ethylcellulose (EC) NPs was intended to obtain very small particles in a size range below 50 nm. The proportion and size of the small particle fraction (SPF) depended on the surfactant as well as on the EC type and concentration. The preparation was conducted with different pharmaceutically relevant surfactants (polyoxyethylene (23) lauryl ether, sodium dodecyl sulfate, cetyltrimethylammonium bromide, polyvinyl alcohol and polysorbate 20) and all permitted obtaining very small NPs. After purification from excess surfactant by diafiltration and separation of the SPF by centrifugation, monodispersed particles with mean sizes between 20.6 ± 2.3 nm and 49.7 ± 4.8 nm could be isolated. The entrapment of a lipophilic model drug led to encapsulation rates between 34.0 ± 2.4% and 78.2 ± 12.6%, which were size and surfactant dependent. The preparation of polymeric NPs in a size below 50 nm by a simple centrifugation step holds promise for therapeutic applications where larger particles would be inefficient.

  15. Bi-modal nanoheteroepitaxy of GaAs on Si by metal organic vapor phase epitaxy

    NASA Astrophysics Data System (ADS)

    Prieto, Ivan; Kozak, Roksolana; Skibitzki, Oliver; Rossell, Marta D.; Zaumseil, Peter; Capellini, Giovanni; Gini, Emilio; Kunze, Karsten; Arroyo Rojas Dasilva, Yadira; Erni, Rolf; Schroeder, Thomas; von Känel, Hans

    2017-03-01

    Nano-heteroepitaxial growth of GaAs on Si(001) by metal organic vapor phase epitaxy was investigated to study emerging materials phenomena on the nano-scale of III-V/Si interaction. Arrays of Si nano-tips (NTs) embedded in a SiO2 matrix were used as substrates. The NTs had top Si openings of 50-90 nm serving as seeds for the selective growth of GaAs nano-crystals (NCs). The structural and morphological properties were investigated by high resolution scanning electron microscopy, atomic force microscopy, electron backscatter diffraction, x-ray diffraction, and high resolution scanning transmission electron microscopy. The GaAs growth led to epitaxial NCs featuring a bi-modal distribution of size and morphology. NCs of small size exhibited high structural quality and well-defined {111}-{100} faceting. Larger clusters had less regular shapes and contained twins. The present work shows that the growth of high quality GaAs NCs on Si NTs is feasible and can provide an alternate way to the integration of compound semiconductors with Si micro- and opto-electronics technology.

  16. Discrete Step Sizes of Molecular Motors Lead to Bimodal Non-Gaussian Velocity Distributions under Force.

    PubMed

    Vu, Huong T; Chakrabarti, Shaon; Hinczewski, Michael; Thirumalai, D

    2016-08-12

    Fluctuations in the physical properties of biological machines are inextricably linked to their functions. Distributions of run lengths and velocities of processive molecular motors, like kinesin-1, are accessible through single-molecule techniques, but rigorous theoretical models for these probabilities are lacking. Here, we derive exact analytic results for a kinetic model to predict the resistive force (F)-dependent velocity [P(v)] and run length [P(n)] distribution functions of generic finitely processive molecular motors. Our theory quantitatively explains the zero force kinesin-1 data for both P(n) and P(v) using the detachment rate as the only parameter. In addition, we predict the F dependence of these quantities. At nonzero F, P(v) is non-Gaussian and is bimodal with peaks at positive and negative values of v, which is due to the discrete step size of kinesin-1. Although the predictions are based on analyses of kinesin-1 data, our results are general and should hold for any processive motor, which walks on a track by taking discrete steps.

  17. Discrete Step Sizes of Molecular Motors Lead to Bimodal Non-Gaussian Velocity Distributions under Force

    NASA Astrophysics Data System (ADS)

    Vu, Huong T.; Chakrabarti, Shaon; Hinczewski, Michael; Thirumalai, D.

    2016-08-01

    Fluctuations in the physical properties of biological machines are inextricably linked to their functions. Distributions of run lengths and velocities of processive molecular motors, like kinesin-1, are accessible through single-molecule techniques, but rigorous theoretical models for these probabilities are lacking. Here, we derive exact analytic results for a kinetic model to predict the resistive force (F )-dependent velocity [P (v )] and run length [P (n )] distribution functions of generic finitely processive molecular motors. Our theory quantitatively explains the zero force kinesin-1 data for both P (n ) and P (v ) using the detachment rate as the only parameter. In addition, we predict the F dependence of these quantities. At nonzero F , P (v ) is non-Gaussian and is bimodal with peaks at positive and negative values of v , which is due to the discrete step size of kinesin-1. Although the predictions are based on analyses of kinesin-1 data, our results are general and should hold for any processive motor, which walks on a track by taking discrete steps.

  18. Analysis of the bimodal chemiluminescence pattern stimulated in human neutrophils by chemotactic factors.

    PubMed Central

    Bender, J G; Van Epps, D E

    1983-01-01

    Chemotactic factors, which are important in attracting neutrophils to inflammatory sites, have also been shown to stimulate oxidative metabolism, resulting in increased chemiluminescence and release of superoxide anion (O2-). We observed a unique bimodal chemiluminescence pattern upon stimulation with either the complement-derived factor C5a or formyl-methionyl-leucyl-phenylalanine. A sharp peak of activity occurred within 1 to 2 min, and a second more extended peak was seen between 3 and 6 min. Enhancement of both peaks occurred when the cells were pretreated with cytochalasin B. Expression of both peaks was found to be related to cell density, and expression of the second peak was not dependent upon extracellular metabolites released during the first peak. Cells preincubated in luminol and then thoroughly washed responded with only a single peak coincident with the second peak. Together these findings indicate that the first peak is extracellular in origin, whereas the second peak is cell associated. Studies with scavengers of oxygen intermediates and inhibitors of myeloperoxidase for the oxidation of luminol, which may occur in part through the formation of HOCl as well as through a non-HOCl-mediated mechanism. Evidence for a non-HOCl-mediated mechanism comes from experiments in which luminol, myeloperoxidase, and O2- generated by xanthine-xanthine oxidase produce luminescence in the absence of chloride ion. These studies provide further insight into the sequence of events which occur during the stimulation of neutrophils with chemotactic factors and the nature of neutrophil chemiluminescence. PMID:6309658

  19. Modeling stick-slip-separation dynamics in a bimodal standing wave ultrasonic motor

    NASA Astrophysics Data System (ADS)

    Li, Xiang; Yao, Zhiyuan; Lv, Qibao; Liu, Zhen

    2016-11-01

    Ultrasonic motor (USM) is an electromechanical coupling system with ultrasonic vibration, which is driven by the frictional contact force between the stator (vibrating body) and the rotor/slider (driven body). Stick-slip motion can occur at the contact interface when USM is operating, which may affect the performance of the motor. This paper develops a physically-based model to investigate the complex stick-slip-separation dynamics in a bimodal standing wave ultrasonic motor. The model includes both friction nonlinearity and intermittent separation nonlinearity of the system. Utilizing Hamilton's principle and assumed mode method, the dynamic equations of the stator are deduced. Based on the dynamics of the stator and the slider, sticking force during the stick phase is derived, which is used to examine the stick-to-slip transition. Furthermore, the stick-slip-separation kinematics is analyzed by establishing analytical criteria that predict the transition between stick, slip and separation of the interface. Stick-slip-separation motion is observed in the resulting model, and numerical simulations are performed to study the influence of parameters on the range of possible motions. Results show that stick-slip motion can occur with greater preload and smaller voltage amplitude. Furthermore, a dimensionless parameter is proposed to predict the occurrence of stick-slip versus slip-separation motions, and its role in designing ultrasonic motors is discussed. It is shown that slip-separation motion is favorable for the slider velocity.

  20. Nonlinear probability distributions of waves in bimodal following and crossing seas generated in laboratory experiments

    NASA Astrophysics Data System (ADS)

    Petrova, P. G.; Guedes Soares, C.

    2013-10-01

    This paper presents an analysis of the nonlinear distributions of crests, troughs and heights of deep water waves from mixed following sea states generated mechanically in an offshore basin and compares with previous results for mixed crossing seas from the same experiment. The random signals at the wavemaker in both types of mixed seas are characterized by bimodal spectra following the model of Guedes Soares (1984). In agreement with the Benjamin-Feir mechanism, the high-frequency spectrum shows decrease of the peak magnitude and downshift of the peak with the distance, as well as reduction of the tail. The observed statistics and probabilistic distributions exhibit, in general, increasing effects of third-order nonlinearity with the distance from the wavemaker. However, this effect is less pronounced in the wave systems with two following wave trains than in the crossing seas with identical initial spectral characteristics. The relevance of third-order effects due to free modes only is demonstrated and assessed by excluding the vertically asymmetric distortions induced by bound-wave effects of second and third order. The fact that for records characterized by relatively large coefficient of kurtosis, the empirical distributions for the non-skewed profiles continue deviating from the linear predictions, corroborate the relevance of free-wave interactions and thus the need of using higher-order models for the description of wave data.