130 research outputs found

    Synthesis of (+)-Officinalic Acid

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    A new concept for the biosynthesis of officinalic acid (1), a C30-metabolitefrom the fungus Laricifomes officinalis, had led to an efficient synthesis of the racemic form of this compound. The key step involves a Diels-Alder dimerization of the readily available enone acid (±)-3, which furnishes (±)-officinalic acid in 420/0 yield. A byproduct formed in the same reaction in 10% yield has been named isoofficinalic acid and shown by spectroscopic techniques to possess structure 11

    Affect and persuasion: mood effects on the processing of message content and context cues and on subsequent behavior

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    Es werden zwei Experimente vorgestellt, die den Einfluß der Stimmung eines Rezipienten auf die Verarbeitung der alltĂ€glichen Kommunikation und sein spĂ€teres Verhalten untersuchen. Es zeigt sich, daß eine positive Stimmung die Motivation einer Person verringert, systematisch den Inhalt einer Mitteilung als auch damit im Zusammenhang stehende Informationen zu verarbeiten. Ihr Verhalten widerspiegelt weniger die Differenzierungen im Mitteilungsinhalt als das Verhalten von Personen in neutraler Stimmung. (psz)'Two experiments are reported examining the impact of recipient's mood on the processing of simple, everyday persuasive communications and on subsequent behavior. Consistent with the general assumption that affective states may inform an individual about the state of its current environment, it was found that affective states may inform an individual about the state of its current environment, it was found that positive (as compared to neutral or negative) mood reduced subjects' motivation to systematically process both content information and contextual cues. Specifically, experiment 1 demonstrated that, in a field setting, the behavior of subjects who had been put in a good mood was less likely to reflect differences in message content than the behavior of neutral mood subjects. Experiment 2 replicated and extended this finding, showing that good mood subject's behavior was uninfluenced by content as well as context information, whereas bad mood subjects did make use of both types of information. Subject's cognitive responses paralleled the behavioral data. The results are discussed in terms of their compatibility with contemporary models of persuasion, and their implications for future research on mood and persuasion and on the interplay of affect and cognition in general are considered.' (author's abstract

    Exchange-enhanced Ultrastrong Magnon-Magnon Coupling in a Compensated Ferrimagnet

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    The ultrastrong coupling of (quasi-)particles has gained considerable attention due to its application potential and richness of the underlying physics. Coupling phenomena arising due to electromagnetic interactions are well explored. In magnetically ordered systems, the quantum-mechanical exchange-interaction should furthermore enable a fundamentally different coupling mechanism. Here, we report the observation of ultrastrong intralayer exchange-enhanced magnon-magnon coupling in a compensated ferrimagnet. We experimentally study the spin dynamics in a gadolinium iron garnet single crystal using broadband ferromagnetic resonance. Close to the ferrimagnetic compensation temperature, we observe ultrastrong coupling of clockwise and anticlockwise magnon modes. The magnon-magnon coupling strength reaches more than 30% of the mode frequency and can be tuned by varying the direction of the external magnetic field. We theoretically explain the observed phenomenon in terms of an exchange-enhanced mode-coupling mediated by a weak cubic anisotropy

    3D-HST: A wide-field grism spectroscopic survey with the Hubble Space Telescope

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    We present 3D-HST, a near-infrared spectroscopic Treasury program with the Hubble Space Telescope for studying the processes that shape galaxies in the distant Universe. 3D-HST provides rest-frame optical spectra for a sample of ~7000 galaxies at 1<z<3.5, the epoch when 60% of all star formation took place, the number density of quasars peaked, the first galaxies stopped forming stars, and the structural regularity that we see in galaxies today must have emerged. 3D-HST will cover 3/4 (625 sq.arcmin) of the CANDELS survey area with two orbits of primary WFC3/G141 grism coverage and two to four parallel orbits with the ACS/G800L grism. In the IR these exposure times yield a continuum signal-to-noise of ~5 per resolution element at H~23.1 and a 5sigma emission line sensitivity of 5x10-17 erg/s/cm2 for typical objects, improving by a factor of ~2 for compact sources in images with low sky background levels. The WFC3/G141 spectra provide continuous wavelength coverage from 1.1-1.6 um at a spatial resolution of ~0."13, which, combined with their depth, makes them a unique resource for studying galaxy evolution. We present the preliminary reduction and analysis of the grism observations, including emission line and redshift measurements from combined fits to the extracted grism spectra and photometry from ancillary multi-wavelength catalogs. The present analysis yields redshift estimates with a precision of sigma(z)=0.0034(1+z), or sigma(v)~1000 km/s. We illustrate how the generalized nature of the survey yields near-infrared spectra of remarkable quality for many different types of objects, including a quasar at z=4.7, quiescent galaxies at z~2, and the most distant T-type brown dwarf star known. The CANDELS and 3D-HST surveys combined will provide the definitive imaging and spectroscopic dataset for studies of the 1<z<3.5 Universe until the launch of the James Webb Space Telescope.Comment: Replacement reflects version now accepted by ApJS. A preliminary data release intended to provide a general illustration of the WFC3 grism data is available at http://3dhst.research.yale.edu

    Multi-Object Near-IR H-alpha Spectroscopy of z~1 star-forming galaxies in the HDF-N

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    We present preliminary results from a programme to obtain multi-object near-infrared spectroscopy of galaxies at redshifts 0.7<z<1.50.7<z<1.5. We are using the instrument CIRPASS (the Cambridge Infra-Red PAnoramic Survey Spectrograph), in multi-object mode, to survey H-alpha in galaxies at z∌1z\sim1. We aim to address the true star formation history of the universe at this epoch: potentially the peak period of star formation activity. H-alpha is the same star formation measure used at low redshift, and hence we can trace star formation without the systematic uncertainties of using different calibrators in different redshift bins, or the extreme dust extinction in the rest-UV. CIRPASS has been successfully demonstrated in multi-object mode on the AAT and WHT. Here we present preliminary results from one of our fields, the Hubble Deep Field North, observed with the WHT. With 150 fibres deployed over an unvignetted field of ∌15\sim15arcmin, we have several detections of H-alpha from star forming galaxies at 0.8<z<1.00.8<z<1.0 and present spectra of the seven brightest of these. By pre-selecting galaxies with redshifts such that H-alpha will appear between the OH sky lines, we can detect star formation rates of 5h70−2M⊙yr−15 h^{-2}_{70} M_{\odot} {\rm yr}^{-1} (5σ5 \sigma in 3-hours, ΩM=0.3\Omega_M=0.3, ΩΛ=0.7\Omega_{\Lambda}=0.7). It appears that star formation rates inferred from H-alpha are, on average, a factor of more than two higher than those based on the UV continuum alone.Comment: 6 pages, 3 figures, accepted for publication in MNRAS Letter

    Perisylvian white matter connectivity in the human right hemisphere

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    Background By using diffusion tensor magnetic resonance imaging (DTI) and subsequent tractography, a perisylvian language network in the human left hemisphere recently has been identified connecting Brocas's and Wernicke's areas directly (arcuate fasciculus) and indirectly by a pathway through the inferior parietal cortex. Results Applying DTI tractography in the present study, we found a similar three-way pathway in the right hemisphere of 12 healthy individuals: a direct connection between the superior temporal and lateral frontal cortex running in parallel with an indirect connection. The latter composed of a posterior segment connecting the superior temporal with the inferior parietal cortex and an anterior segment running from the inferior parietal to the lateral frontal cortex. Conclusion The present DTI findings suggest that the perisylvian inferior parietal, superior temporal, and lateral frontal corticies are tightly connected not only in the human left but also in the human right hemisphere

    Activation of superior colliculi in humans during visual exploration

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    <p>Abstract</p> <p>Background</p> <p>Visual, oculomotor, and – recently – cognitive functions of the superior colliculi (SC) have been documented in detail in non-human primates in the past. Evidence for corresponding functions of the SC in humans is still rare. We examined activity changes in the human tectum and the lateral geniculate nuclei (LGN) in a visual search task using functional magnetic resonance imaging (fMRI) and anatomically defined regions of interest (ROI). Healthy subjects conducted a free visual search task and two voluntary eye movement tasks with and without irrelevant visual distracters. Blood oxygen level dependent (BOLD) signals in the SC were compared to activity in the inferior colliculi (IC) and LGN.</p> <p>Results</p> <p>Neural activity increased during free exploration only in the SC in comparison to both control tasks. Saccade frequency did not exert a significant effect on BOLD signal changes. No corresponding differences between experimental tasks were found in the IC or the LGN. However, while the IC revealed no signal increase from the baseline, BOLD signal changes at the LGN were consistently positive in all experimental conditions.</p> <p>Conclusion</p> <p>Our data demonstrate the involvement of the SC in a visual search task. In contrast to the results of previous studies, signal changes could not be seen to be driven by either visual stimulation or oculomotor control on their own. Further, we can exclude the influence of any nearby neural structures (e.g. pulvinar, tegmentum) or of typical artefacts at the brainstem on the observed signal changes at the SC. Corresponding to findings in non-human primates, our data support a dependency of SC activity on functions beyond oculomotor control and visual processing.</p

    [Avian cytogenetics goes functional] Third report on chicken genes and chromosomes 2015

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    High-density gridded libraries of large-insert clones using bacterial artificial chromosome (BAC) and other vectors are essential tools for genetic and genomic research in chicken and other avian species... Taken together, these studies demonstrate that applications of large-insert clones and BAC libraries derived from birds are, and will continue to be, effective tools to aid high-throughput and state-of-the-art genomic efforts and the important biological insight that arises from them

    A research agenda for improving national Ecological Footprint accounts

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