8,316 research outputs found
Phase Space Manipulation of Cold Free Radical OH Molecules
We report bunching, slowing, and acceleration of a supersonically cooled beam
of diatomic hydroxyl radicals (OH). \textit{In situ} observation of
laser-induced fluorescence along the beam propagation path allows for detailed
characterization of longitudinal phase-space manipulation of OH molecules
through the Stark effect by precisely sequenced inhomogeneous electric fields.Comment: 5 pages, 4 color figure
Collision-induced conformational changes in glycine
We present quantum dynamical calculations on the conformational changes of glycine in collisions with the He, Ne, and Ar rare-gas atoms. For two conformer interconversion processes (III-->I and IV-->I), we find that the probability of interconversion is dependent on several factors, including the energy of the collision, the angle at which the colliding atom approaches the glycine molecule, and the strength of the glycine-atom interaction. Furthermore, we show that attractive interactions between the colliding atom and the glycine molecule catalyze conformer interconversion at low collision energies. In previous infrared spectroscopy studies of glycine trapped in rare-gas matrices and helium clusters, conformer III has been consistently observed, but conformer IV has yet to be conclusively detected. Because of the calculated thermodynamic stability of conformer IV, its elusiveness has been attributed to the IV-->I conformer interconversion process. However, our calculations present little indication that IV-->I interconversion occurs more readily than III-->I interconversion. Although we cannot determine whether conformer IV interconverts during experimental Ne- and Ar-matrix depositions, our evidence suggests that the conformer should be present in helium droplets. Anharmonic vibrational frequency calculations illustrate that previous efforts to detect conformer IV may have been hindered by the overlap of its IR-absorption bands with those of other conformers. We propose that the redshifted symmetric –CH2 stretch of conformer IV provides a means for its conclusive experimental detection
Symbolic Reachability Analysis of B through ProB and LTSmin
We present a symbolic reachability analysis approach for B that can provide a
significant speedup over traditional explicit state model checking. The
symbolic analysis is implemented by linking ProB to LTSmin, a high-performance
language independent model checker. The link is achieved via LTSmin's PINS
interface, allowing ProB to benefit from LTSmin's analysis algorithms, while
only writing a few hundred lines of glue-code, along with a bridge between ProB
and C using ZeroMQ. ProB supports model checking of several formal
specification languages such as B, Event-B, Z and TLA. Our experiments are
based on a wide variety of B-Method and Event-B models to demonstrate the
efficiency of the new link. Among the tested categories are state space
generation and deadlock detection; but action detection and invariant checking
are also feasible in principle. In many cases we observe speedups of several
orders of magnitude. We also compare the results with other approaches for
improving model checking, such as partial order reduction or symmetry
reduction. We thus provide a new scalable, symbolic analysis algorithm for the
B-Method and Event-B, along with a platform to integrate other model checking
improvements via LTSmin in the future
Vertical bone augmentation and regular implants versus short implants in the vertically deficient posterior mandible:a systematic review and meta-analysis of randomized studies
Item does not contain fulltextThe aim of this study was to perform a systematic review and meta-analysis of randomized controlled trials (RCTs) comparing the outcomes of short dental implants (≤7mm) versus vertical bone augmentation followed by regular dental implants (>7mm) in the deficient posterior mandible. In total, eight RCTs (six using interpositional sandwich grafting and two using a guided bone regeneration technique) were reported in 17 articles at different time points. In the meta-analysis of the sandwich group, the relative risk (RR) for implant loss at 1year was in favour of short implants (RR 0.41, P=0.02), while no significant difference was found at 3 years (RR 0.65, P=0.43), 5 years (RR 1.08, P=0.86), or 8 years (RR 1.53, P=0.52). The risk of complications was in favour of short implants (RR 0.34, P=0.0002), as was the mean difference in marginal bone resorption after 1 year (-0.09mm, P=0.17), 3 years (-0.32mm, P<0.00001), 5 years (-0.65mm, P<0.00001), and 8 years (-0.88, P<0.00001). The mean residual osseointegration length of the implants was between 2.94mm and 4.44mm in the short implants group and between 7.97mm and 8.62mm in the regular implants group after 5 years. In conclusion, in the deficient atrophic posterior mandible, short implants and regular implants demonstrate comparable outcomes within the first 5 years. Patients who are fit for surgery should be informed about the risks and benefits of both options
Consciousness in the Universe is Scale Invariant and Implies an Event Horizon of the Human Brain
Our brain is not a "stand alone" information processing organ: it acts as a central part of our integral nervous system with recurrent information exchange with the entire organism and the cosmos. In this study, the brain is conceived to be embedded in a holographic structured field that interacts with resonant sensitive structures in the various cell types in our body. In order to explain earlier reported ultra-rapid brain responses and effective operation of the meta-stable neural system, a field-receptive mental workspace is proposed to be communicating with the brain. Our integral nervous system is seen as a dedicated neural transmission and multi-cavity network that, in a non-dual manner, interacts with the proposed supervening meta-cognitive domain. Among others, it is integrating discrete patterns of eigen-frequencies of photonic/solitonic waves, thereby continuously updating a time-symmetric global memory space of the individual. Its toroidal organization allows the coupling of gravitational, dark energy, zero-point energy field (ZPE) as well as earth magnetic fields energies and transmits wave information into brain tissue, that thereby is instrumental in high speed conscious and sub-conscious information processing. We propose that the supposed field-receptive workspace, in a mutual interaction with the whole nervous system, generates self-consciousness and is conceived as operating from a 4th spatial dimension (hyper-sphere). Its functional structure is adequately defined by the geometry of the torus, that is envisioned as a basic unit (operator) of space-time. The latter is instrumental in collecting the pattern of discrete soliton frequencies that provided an algorithm for coherent life processes, as earlier identified by us. It is postulated that consciousness in the entire universe arises through, scale invariant, nested toroidal coupling of various energy fields, that may include quantum error correction. In the brain of the human species, this takes the form of the proposed holographic workspace, that collects active information in a "brain event horizon", representing an internal and fully integral model of the self. This brain-supervening workspace is equipped to convert integrated coherent wave energies into attractor type/standing waves that guide the related cortical template to a higher coordination of reflection and action as well as network synchronicity, as required for conscious states. In relation to its scale-invariant global character, we find support for a universal information matrix, that was extensively described earlier, as a supposed implicate order as well as in a spectrum of space-time theories in current physics. The presence of a field-receptive resonant workspace, associated with, but not reducible to, our brain, may provide an interpretation framework for widely reported, but poorly understood transpersonal conscious states and algorithmic origin of life. It also points out the deep connection of mankind with the cosmos and our major responsibility for the future of our planet.</p
Microwave Lens for Polar Molecules
We here report on the implementation of a microwave lens for neutral polar
molecules suitable to focus molecules both in low-field-seeking and in
high-field-seeking states. By using the TE_11m modes of a 12 cm long
cylindrically symmetric microwave resonator, Stark-decelerated ammonia
molecules are transversally confined. We investigate the focusing properties of
this microwave lens as a function of the molecules' velocity, the detuning of
the microwave frequency from the molecular resonance frequency, and the
microwave power. Such a microwave lens can be seen as a first important step
towards further microwave devices, such as decelerators and traps.Comment: 4 pages, 3 figure
Mesoscopic order and the dimentionality of long-range resonance energy transfer in supramolecular semiconductors
We present time-resolved photoluminescence measurements on two series of
oligo-p-phenylenevinylene materials that self-assemble into supramolecular
nanostructures with thermotropic reversibility in dodecane. One set of
derivatives form chiral, helical stacks while the second set form less
organised, frustrated stacks. Here we study the effects of supramolecular
organisation on the resonance energy transfer rates. We measure these rates in
nanoassemblies formed with mixed blends of oligomers and compare them with the
rates predicted by Foerster theory. Our results and analysis show that control
of supramolecular order in the nanometre lengthscale has a dominant effect on
the efficiency and dimentionality of resonance energy transfer.Comment: 17 Pages, 5 Figures, Submitted to J. Chem. Phy
Influence of electron beam irradiation on the microrheology of incompatible polymer blends: Thread break‐up and coalescence
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