Showing 701 - 710 of 733 Items
Measurement of the c+ decay-asymmetry parameter
Date: 1990-01-01
Creator: P. Avery, D. Besson, L. Garren, J. Yelton, K., Kinoshita, F. M. Pipkin, M. Procario, Richard Wilson, J. Wolinski, D. Xiao, Y. Zhu, R. Ammar, P. Baringer, D. Coppage, R. Davis, P. Haas, M. Kelly, N. Kwak, Ha Lam, S. Ro, Y. Kubota, J. K. Nelson, D. Perticone, R. Poling, R. Fulton, T. Jensen, D. R. Johnson, H. Kagan, R. Kass, F. Morrow, J. Whitmore
Access: Open access
- We report a measurement of polarization in the two-body decay c+, in nonresonant e+e- interactions from data taken with the CLEO detector. Using these data we have determined the parity-violating asymmetry decay parameter c to be -1.0-0.0+0.4. We see no evidence for significant c+ polarization. © 1990 The American Physical Society.
In situ HCR in non-traditional arthropods
Date: 2024-01-25
Creator: Heather Bruce, Hadley Wilson Horch
Access: Open access
- Visualizing the expression of genes is a fundamental tool in molecular biology. Traditional colorimetric in situ hybridization using long RNA probes has been a staple for visualizing gene expression but has many drawbacks. In situ HCR v3.0, developed by Choi et. al. 2018, offers improvements over traditional in situs in nearly every aspect: probes can simply be ordered rather than painstakingly cloned and transcribed, which also makes them cost-effective; an HCR takes just three days to complete rather than five or more days; HCR is robust and works well for first-time users; and HCR probes can be multiplexed, allowing four to eight genes to be visualized in a single sample. HCR has been used successfully in many arthropods, including insects (Drosophila, Tribolium), crustaceans (Parhyale, Daphnia, Artemia), and chelicerates (Limulus horseshoe crab, Acanthoscurria tarantula). In this demo, you will learn how to design and order HCR probes as well as best practices for experimental design.
Search for τ-→γμ-: A test of lepton number conservation
Date: 1993-01-01
Creator: A. Bean, J. Gronberg, R. Kutschke, S. Menary, R. J., Morrison, H. Nelson, J. Richman, H. Tajima, D. Schmidt, D. Sperka, M. Witherell, M. Procario, S. Yang, M. Daoudi, W. T. Ford, D. R. Johnson, K. Lingel, M. Lohner, P. Rankin, J. G. Smith, J. P. Alexander, C. Bebek, K. Berkelman, D. Besson, T. E. Browder, D. G. Cassel, D. M. Coffman, P. S. Drell, R. Ehrlich, R. S. Galik, M. Garcia-Sciveres
Access: Open access
- A search for the lepton mumber violating decay of the τ lepton to the γμ final state has been performed with the CLEO II detector at the Cornell e+e- storage ring CESR. In a data sample that corresponds to an integrated luminosity of 1.55 fb-1, we observe no candidates in the signal region. We thus determine an upper limit of B(τ-→γμ-)<4. 2×10-6 at 90% confidence level. © 1993 The American Physical Society.
Sensory-based niche partitioning in a multiple predator-multiple prey community
Date: 2015-05-20
Creator: Jay J. Falk, Hannah M. Ter Hofstede, Patricia L. Jones, Marjorie M. Dixon, Paul A., Faure, Elisabeth K.V. Kalko, Rachel A. Page
Access: Open access
- Many predators and parasites eavesdrop on the communication signals of their prey. Eavesdropping is typically studied as dyadic predator-prey species interactions; yet in nature, most predators target multiple prey species and most prey must evade multiple predator species. The impact of predator communities on prey signal evolution is not well understood. Predators could converge in their preferences for conspicuous signal properties, generating competition among predators and natural selection on particular prey signal features. Alternatively, predator species could vary in their preferences for prey signal properties, resulting in sensory-based niche partitioning of prey resources. In the Neotropics, many substrate-gleaning bats use the mate-attraction songs of male katydids to locate them as prey. We studied mechanisms of niche partitioning in four substrate- gleaning bat species and found they are similar in morphology, echolocation signal design and prey-handling ability, but each species preferred different acoustic features of male song in 12 sympatric katydid species. This divergence in predator preference probably contributes to the coexistence of many substrate-gleaning bat species in the Neotropics, and the substantial diversity in the mate-attraction signals of katydids. Our results provide insight into how multiple eavesdropping predator species might influence prey signal evolution through sensory-based niche partitioning.
TAKs, thylakoid membrane protein kinases associated with energy transduction
Date: 1999-04-02
Creator: Shaun Snyders, Bruce D. Kohorn
Access: Open access
- The phosphorylation of proteins within the eukaryotic photosynthetic membrane is thought to regulate a number of photosynthetic processes in land plants and algae. Both light quality and intensity influence protein kinase activity via the levels of reductants produced by the thylakoid electron transport chain. We have isolated a family of proteins called TAKs, Arabidopsis thylakoid membrane threonine kinases that phosphorylate the light harvesting complex proteins. TAK activity is enhanced by reductant and is associated with the photosynthetic reaction center II and the cytochrome b6f complex. TAKs are encoded by a gene family that has striking similarity to transforming growth factor β receptors of metazoans. Thus thylakoid protein phosphorylation may be regulated by a cascade of reductant-controlled membrane-bound protein kinases.
Fermions destabilize electroweak strings
Date: 1995-01-01
Creator: Stephen G. Naculich
Access: Open access
- Z strings in the Weinberg-Salam model including fermions are unstable for all values of the parameters. The cause of this instability is the fermion vacuum energy in the Z-string background. Z strings with nonzero fermion densities, however, may still be stable. © 1995 The American Physical Society.
Circadian signaling in Homarus americanus: Region-specific de novo assembled transcriptomes show that both the brain and eyestalk ganglia possess the molecular components of a putative clock system
Date: 2018-07-01
Creator: Andrew E. Christie, Andy Yu, Micah G. Pascual, Vittoria Roncalli, Matthew C., Cieslak, Amanda N. Warner, Tess J. Lameyer, Meredith E. Stanhope, Patsy S. Dickinson, J. Joe Hull
Access: Open access
- Essentially all organisms exhibit recurring patterns of physiology/behavior that oscillate with a period of ~24-h and are synchronized to the solar day. Crustaceans are no exception, with robust circadian rhythms having been documented in many members of this arthropod subphylum. However, little is known about the molecular underpinnings of their circadian rhythmicity. Moreover, the location of the crustacean central clock has not been firmly established, although both the brain and eyestalk ganglia have been hypothesized as loci. The American lobster, Homarus americanus, is known to exhibit multiple circadian rhythms, and immunodetection data suggest that its central clock is located within the eyestalk ganglia rather than in the brain. Here, brain- and eyestalk ganglia-specific transcriptomes were generated and used to assess the presence/absence of transcripts encoding the commonly recognized protein components of arthropod circadian signaling systems in these two regions of the lobster central nervous system. Transcripts encoding putative homologs of the core clock proteins clock, cryptochrome 2, cycle, period and timeless were found in both the brain and eyestalk ganglia assemblies, as were transcripts encoding similar complements of putative clock-associated, clock input pathway and clock output pathway proteins. The presence and identity of transcripts encoding core clock proteins in both regions were confirmed using PCR. These findings suggest that both the brain and eyestalk ganglia possess all of the molecular components needed for the establishment of a circadian signaling system. Whether the brain and eyestalk clocks are independent of one another or represent a single timekeeping system remains to be determined. Interestingly, while most of the proteins deduced from the identified transcripts are shared by both the brain and eyestalk ganglia, assembly-specific isoforms were also identified, e.g., several period variants, suggesting the possibility of region-specific variation in clock function, especially if the brain and eyestalk clocks represent independent oscillators.
Inclusive and exclusive decays of B mesons to final states including charm and charmonium mesons
Date: 1992-01-01
Creator: D. Bortoletto, D. N. Brown, J. Dominick, R. L. McIlwain, D. H., Miller, M. Modesitt, E. I. Shibata, S. Schaffner, I. P.J. Shipsey, M. Battle, H. Kroha, K. Sparks, E. H. Thorndike, C. H. Wang, M. Goldberg, T. Haupt, N. Horwitz, V. Jain, G. C. Moneti, Y. Rozen, P. Rubin, T. Skwarnicki, V. Sharma, S. Stone, M. Thusalidas, W. M. Yao, G. Zhu, A. V. Barnes, J. Bartelt, S. E. Csorna, T. Letson
Access: Open access
- We have studied hadronic decays of B mesons. We report measurements of exclusive branching ratios of several charm decay modes of B mesons to final states with a D or D* and one to three charged pions or a charged and to final states with a or , a kaon, and up to two charged pions. We have also measured inclusive branching ratios for B decays to D and D* and the spectra of these particles in B decays. The total charm content in B decay is found to be (10112)%. The branching ratios and spectra are compared to form-factor models. We extract the parameters a1 and a2 of the model of Bauer, Stech, and Wirbel and the DS decay constant. The masses of the B0 and B- mesons are measured. The mass difference between B0 and B- is found to be -0.40.60.5 MeV/c2. © 1992 The American Physical Society.
The 10kb Drosophila virus 28S rDNA intervening sequence is flanked by a disect repeat of 14 base pairs of coding sequence
Date: 1980-08-25
Creator: Peter M.M. Rae, Bruce D. Kohorn, Robert P. Wade
Access: Open access
- Most repeat units of rDNA in Drosophila virilis are interrupted in the 28S rRNA coding region by an intervening sequence about 10 kb in length; uninterrupted repeats have a length of about 11 kb. We have sequenced the coding/intervening sequence junctions and flanking regions in two independent clones of interrupted rDNA, and the corresponding 28S rRNA coding region in a clone of uninterrupted rDNA. The intervening sequence is terminated at both ends by a direct repeat of a fourteen nucleotide sequence that is present once in the corresponding region of an intact gene. This is a phenomenon associated with transposable elements in other eukaryotes and in prokaryotes, and the Drosophila rDNA intervening sequence is discussed in this context. We have compared more than 200 nucleotides of the D. virilis 28S rRNA gene with sequences of homologous regions of rDNA in Tetrahymena pigmentosa (Wild and Sommer, 1980) and Xenopus laevis (Gourse and Gerbi, 1980): There is 93% sequence homology among the diverse species, so that the rDNA region in question (about two-thirds of the way into the 28S rRNA coding sequence) has been very highly conserved in eukaryote evolution. The intervening sequence in T. pigmentosa is at a site 79 nucleotides upstream from the insertion site of the Drosophila intervening sequence. © 1980 IRL Press Limited.
When to approach novel prey cues? Social learning strategies in frog-eating bats
Date: 2013-10-23
Creator: Patricia L. Jones, Michael J. Ryan, Victoria Flores, Rachel A. Page
Access: Open access
- Animals can use different sources of information when making decisions. Foraging animals often have access to both self-acquired and socially acquired information about prey. The fringe-lipped bat, Trachops cirrhosus, hunts frogs by approaching the calls that frogs produce to attract mates.We examined howthe reliability of self-acquired prey cues affects social learning of novel prey cues. We trained bats to associate an artificial acoustic cue (mobile phone ringtone) with food rewards. Bats were assigned to treatments in which the trained cue was either an unreliable indicator of reward (rewarded 50% of the presentations) or a reliable indicator (rewarded 100% of the presentations), and they were exposed to a conspecific tutor foraging on a reliable (rewarded 100%) novel cue or to the novel cue with no tutor. Bats whose trained cue was unreliable and who had a tutor were significantly more likely to preferentially approach the novel cue when compared with bats whose trained cue was reliable, and to bats that had no tutor. Reliability of self-acquired prey cues therefore affects social learning of novel prey cues by frog-eating bats. Examining when animals use social information to learn about novel prey is key to understanding the social transmission of foraging innovations. © 2013 The Author(s) Published by the Royal Society.