139 research outputs found
Synthesis of (+)-Officinalic Acid
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
Es werden zwei Experimente vorgestellt, die den Einfluß der Stimmung eines Rezipienten auf die Verarbeitung der alltäglichen Kommunikation und sein späteres 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
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
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
We present preliminary results from a programme to obtain multi-object
near-infrared spectroscopy of galaxies at redshifts . We are using
the instrument CIRPASS (the Cambridge Infra-Red PAnoramic Survey Spectrograph),
in multi-object mode, to survey H-alpha in galaxies at . 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 arcmin, we have several detections of H-alpha from
star forming galaxies at 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 ( in 3-hours, ,
). 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
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
Rapid Climate Change, Integrated Human–Environment–Historical Records and Societal Resilience in Georgia
In the midlatitudes of the planet, we are facing the imminent disappearance of one of our best high-resolution (pre)historic climate and anthropogenic pollution archives, namely the loss of glacial ice, through accelerated global warming. To capture these records and interpret these vanishing archives, it is imperative that we extract ice-cores from midlatitude regions where glaciers still survive and analyse them within frameworks of inter-disciplinary research. In this paper, we focus on Georgia, part of the Greater Caucasus. Results of ice-core analyses from the region have never, to date, been integrated with its other abundant palaeo-environmental, archaeological and historical sources. We review the results of international projects on palaeo-environmental/geoarchaeological sediment archives, the archaeology of metal economies and preliminary ice-core data in Georgia. Collectively, we show that the different strands need to be integrated to fully explore relationships between climate/landscape change and human societal transformations. We then introduce an inclusive interdisciplinary framework for ongoing research on these themes, with an ultimate future goal of using data from the past to inform societal resilience strategies in the present
Activation of superior colliculi in humans during visual exploration
<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
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
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