113 research outputs found
Coherence Properties of Guided-Atom Interferometers
We present a detailed investigation of the coherence properties of beam
splitters and Mach-Zehnder interferometers for guided atoms. It is demonstrated
that such a setup permits coherent wave packet splitting and leads to the
appearance of interference fringes. We study single-mode and thermal input
states and show that even for thermal input states interference fringes can be
clearly observed, thus demonstrating the multimode operation and the robustness
of the interferometer.Comment: 4 pages, 4 figure
Interferometer-Type Structures for Guided Atoms
We experimentally demonstrate interferometer-type guiding structures for
neutral atoms based on dipole potentials created by micro-fabricated optical
systems. As a central element we use an array of atom waveguides being formed
by focusing a red-detuned laser beam with an array of cylindrical microlenses.
Combining two of these arrays, we realize X-shaped beam splitters and more
complex systems like the geometries for Mach-Zehnder and Michelson-type
interferometers for atoms.Comment: 4 pages, 6 figure
Dependence of radio halo properties on star formation activity and galaxy mass
We investigate the relation between the existence and size of radio halos,
which are believed to be created by star formation (SF) related energy input
into the interstellar medium, and other galaxy properties, most importantly
star formation activity and galaxy mass. Based on radio continuum and H-alpha
observations of a sample of seven late-type spiral galaxies we find a direct,
linear correlation of the radial extent of gaseous halos on the size of the
actively star-forming parts of the galaxy disks. Data of a larger sample of 22
galaxies indicate that the threshold energy input rate into the disk ISM per
unit surface area for the creation of a gaseous halo depends on the mass
surface density of the galaxy, in the sense that a higher threshold must be
surpassed for galaxies with a higher surface density. Because of the good
prediction of the existence of a radio halo from these two parameters, we
conclude that they are important, albeit not the only contributors. The
compactness of the SF-related energy input is also found to be a relevant
factor. Galaxies with relatively compact SF distributions are more likely to
have gaseous halos than others with more widespread SF activity. These results
quantify the so-called "break-out" condition for matter to escape from galaxy
disks, as used in all current models of the interstellar medium and first
defined by Norman and Ikeuchi (1989).Comment: accepted for publication in Astronomy & Astrophysic
Finding Nested Common Intervals Efficiently
International audienceIn this paper, we study the problem of effi ciently fi nding gene clusters formalized by nested common intervals between two genomes represented either as permutations or as sequences. Considering permutations, we give several algorithms whose running time depends on the size of the actual output rather than the output in the worst case. Indeed, we first provide a straightforward O(n^3) time algorithm for finding all nested common intervals. We reduce this complexity by providing an O(n^2) time algorithm computing an irredundant output. Finally, we show, by providing a third algorithm, that fi nding only the maximal nested common intervals can be done in linear time. Considering sequences, we provide solutions (modi cations of previously de ned algorithms and a new algorithm) for di fferent variants of the problem, depending on the treatment one wants to apply to duplicated genes
The Radio Properties of Composite LINER/HII Galaxies
Arcsec-resolution VLA observations -- newly obtained as well as published --
of 40 nearby galaxies are discussed, completing a study of the radio properties
of a magnitude-limited sample of nearby galaxies of the composite LINER/HII
type. Our results reveal an overall detection rate of at least 25% AGN
candidates among these composite sources. The general properties of these AGN
candidates, as compared to non-AGN composite sources and HII galaxies, are
discussed.Comment: Accepted for publication in ApJ
Identifying differential predictors for treatment response to amisulpride and olanzapine combination treatment versus each monotherapy in acutely ill patients with schizophrenia: results of the COMBINE-study
Background
Extensive research has been undertaken to predict treatment response (TR) to antipsychotics. Most studies address TR to antipsychotics in general and as monotherapy, however, it is unknown whether patients might respond favourably to a combination of antipsychotics.
Aims
This study aimed to identify differential predictors for TR to monotherapy with amisulpride or olanzapine compared to a combination of antipsychotics.
Methods
Post-hoc analysis was conducted of data collected from the COMBINE-study, a double-blind, randomized, controlled trial. Demographic and disease-related measures were gathered at baseline to predict TR after eight weeks defined by the Positive and Negative Syndrome Scale. Missing values were accounted for by a random replacement procedure. Attrition effects and multicollinearity were analysed and sets of logistic regression models were calculated for different treatment groups.
Results
Of the 321 randomized patients, 201 completed procedures until week eight and 197 were included in the analyses. For all treatment groups, early TR after two weeks and high subjective well-being under antipsychotics at baseline were robust predictors for TR. The propensity for early side effects also indicated a higher risk of later non-response. Specific parameter estimates were rather similar between treatment groups.
Conclusion
Early TR, drug-related subjective well-being, and early side effect propensity evolved as predictors for later TR whether to monotherapy or combination strategy. Accordingly, due to a lack of differential predictors, early and close monitoring of targeted and unwanted effects is indicated to guide respective treatment decisions
The Nature of Composite LINER/HII Galaxies, As Revealed from High-Resolution VLA Observations
A sample of 37 nearby galaxies displaying composite LINER/HII and pure HII
spectra was observed with the VLA in an investigation of the nature of their
weak radio emission. The resulting radio contour maps overlaid on optical
galaxy images are presented here, together with an extensive literature list
and discussion of the individual galaxies. Radio morphological data permit
assessment of the ``classical AGN'' contribution to the global activity
observed in these ``transition'' LINER galaxies. One in five of the latter
objects display clear AGN characteristics: these occur exclusively in
bulge-dominated hosts.Comment: 31 pages, 27 figures, accepted by ApJ
hTID-1 defines a novel regulator of c-Met Receptor signaling in renal cell carcinomas
The c-Met receptor tyrosine kinase (MetR) is frequently overexpressed and constitutively phosphorylated in a number of human malignancies. Activation of the receptor by its ligand, hepatocyte growth factor (HGF), leads to increased cell proliferation, motility, survival and disruption of adherens junctions. In this study, we show that hTid-1, a DNAJ/Hsp40 chaperone, represents a novel modulator of the MetR signaling pathway. hTid-1 is a co-chaperone of the Hsp70 family of proteins, and has been shown to regulate a number of cellular signaling proteins including several involved in tumorigenic and apoptotic pathways. In this study we demonstrate that hTid-1 binds to unphosphorylated MetR and becomes dissociated from the receptor upon HGF stimulation. Overexpression of the short form of hTid-1 (hTid-1S) in 786-0 renal clear cell carcinomas (RCCs) enhances MetR kinase activity leading to an increase in HGF-mediated cell migration with no discernible effect on cell proliferation. By contrast, knockdown of hTid-1 markedly impairs both the onset and amplitude of MetR phosphorylation in response to HGF without altering receptor protein levels. hTid-1-depleted cells display defective migratory properties, coincident with inhibition of ERK/MAP kinase and STAT3 pathways. Taken together, our findings denote hTid-1S as an essential regulatory component of MetR signaling. We propose that the binding of hTid-1S to MetR may stabilize the receptor in a ligand-competent state and this stabilizing function may influence conformational changes that take place during the catalytic cycle that promote kinase activation. Given the prevalence of HGF/MetR pathway activation in human cancers, targeted inhibition of hTid-1 may be a useful therapeutic in the management of MetR-dependent malignancies
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