Fragmentation, domain formation and atom number fluctuations of a two-species Bose-Einstein condensate in an optical lattice

We theoretically study the loading of a two-species Bose-Einstein condensate to an optical lattice in a tightly-confined one-dimensional trap. Due to quantum fluctuations the relative inter and intra species phase coherence between the atoms and the on-site atom number fluctuations are reduced in the miscible regime. For the immiscible case the fluctuations are enhanced and the atoms form metastable interleaved spatially separated domains where the domain length and its fluctuations are affected by quantum fluctuations.Comment: 32 page

Characteristics of the polymer transport in ratchet systems

Molecules with complex internal structure in time-dependent periodic potentials are studied by using short Rubinstein-Duke model polymers as an example. We extend our earlier work on transport in stochastically varying potentials to cover also deterministic potential switching mechanisms, energetic efficiency and non-uniform charge distributions. We also use currents in the non-equilibrium steady state to identify the dominating mechanisms that lead to polymer transportation and analyze the evolution of the macroscopic state (e.g., total and head-to-head lengths) of the polymers. Several numerical methods are used to solve the master equations and nonlinear optimization problems. The dominating transport mechanisms are found via graph optimization methods. The results show that small changes in the molecule structure and the environment variables can lead to large increases of the drift. The drift and the coherence can be amplified by using deterministic flashing potentials and customized polymer charge distributions. Identifying the dominating transport mechanism by graph analysis tools is found to give insight in how the molecule is transported by the ratchet effect.Comment: 35 pages, 17 figures, to appear in Phys. Rev.

Säveltäjä-klarinetisti Bernhard Crusellin ammatillinen toiminta ja vuorovaikutus Ruotsissa 1795–1833 : Lektio

Non peer reviewe

Structure and regulation of mammalian S-adenosylmethionine decarboxylase

In order to understand the structure and regulation of S-adenosylmethionine decarboxylase, cDNA clones encoding this enzyme have been isolated from rat prostate and human fibroblast cDNA libraries. The authenticity of the cDNAs was verified by: (a) transfecting the Chinese hamster ovary cells with the human cDNA in the pcD vector which resulted in a transient 10-20-fold increase in S-adenosylmethionine decarboxylase activity in recipient cells; and (b) translating the mRNA formed by transcription of the cDNA insert in a reticulocyte lysate and recording an increase in S-adenosylmethionine decarboxylase activity. The amino acid sequences deduced from the cDNAs indicate that the human proenzyme for this protein contains 334 amino acids and has a molecular weight of 38,331 whereas the rat proenzyme contains 333 amino acid residues. The human and rat enzymes are very similar having only 11 amino acid differences and the cDNAs are also closely related showing over 90% homology in the 1617-nucleotide overlap which was sequenced. A further indication of the highly conserved nature of mammalian S-adenosylmethionine decarboxylases is that the amino acid sequences deduced from the human and the rat cDNAs contained peptide sequences identical to those previously reported for the purified bovine enzyme. In vitro transcription/translation experiments showed that the proenzyme is converted to two polypeptides of molecular weights about 32,000 and 6,000 in a processing reaction which generates the prosthetic pyruvate group and that the final enzyme contains both polypeptides. Two forms of S-adenosylmethionine decarboxylase mRNA (2.1 and about 3.4-3.6 kilobases) are present in human and rodent tissues and may originate from the utilization of two different polyadenylation signals. Southern blots of rat genomic DNA indicated that the S-adenosylmethionine decarboxylase gene belongs to a multigene family. Depletion of cellular polyamines by inhibitors or ornithine decarboxylase or the aminopropyltransferases led to an increase in the content of S-adenosylmethionine decarboxylase protein and mRNA, but the elevation in the mRNA was not sufficient to account for all of the change in the enzyme level, particularly in cells in which spermine was depleted

Health-related quality of life in relation to shark symptomatic and radiographic definitions of knee osteoarthritis : data from Osteoarthritis Initiative (OAI) 4-year follow- up study

Background: The purpose was to quantify the decrement in health utility (referred as disutility) associated with knee osteoarthritis (OA) and different symptomatic and radiographic uni- and bilateral definitions of knee OA in a repeated measures design of persons with knee OA or at increased risk of developing knee OA. Methods: Data were obtained from the Osteoarthritis Initiative database. SF-12 health-related quality of life was converted into SF-6D utilities, and were then handled as the health utility loss by subtracting 1.000 from the utility score, yielding a negative value (disutility). Symptomatic OA was defined by radiographic findings (Kellgren-Lawrence, K-L, grade >= 2) and frequent knee pain in the same knee. Radiographic OA was defined by five different definitions (K-L >= 2 unilaterally / bilaterally, or the highest / mean / combination of K-L grades of both knees). Repeated measures generalized estimating equation (GEE) models were used to investigate disutility in relation to these different definitions. Results: Utility decreased with worsening of symptomatic or radiographic status of knee OA. The participants with bilateral and unilateral symptomatic knee OA had 0.03 (p <0.001) and 0.02 (p <0.001) points lower utility scores, respectively, compared with the reference group. The radiographic K-L grade 4 defined as the mean or the highest grade of both knees was related to a decrease of 0.04 (p <0.001) and 0.03 (p <0.001) points in utility scores, respectively, compared to the reference group. Conclusions: Knee OA is associated with diminished health-related quality of life. Health utility can be quantified in relation to both symptomatic and radiographic uni- and bilateral definitions of knee OA, and these definitions are associated with differing disutilities. The performance of symptomatic definition was better, indicating that pain experience is an important factor in knee OA related quality of life.Peer reviewe

On the phenology and seeding potential of sea-ice microalgal species

Sea ice is an important habitat for a wide variety of microalgal species. Depending on the species composition, sea ice can be a seeding source for pelagic phytoplankton blooms after ice melt in spring. Sea-ice algal communities were studied over 2 full winter seasons in 2014 and 2016 at Rothera Research Station, situated at the Western Antarctic Peninsula (WAP). Algal pigment patterns and microscopic observations were combined with photophysiological studies based on fluorescence analyses to monitor and explain the phenology of ice-algal species. Clear patterns in species succession were identified. Young sea ice contained a mixture of algal species including dinoflagellates, cryptophytes and diatoms like Chaetoceros spp. and Fragillariopsis spp. In winter, severe environmental conditions resulted in a decline in species diversity and selection towards heterotrophy. Pennate diatoms like Amphiprora kufferathii and Berkeleya adeliensis were the first to dominate the nutrient-enriched bottom-ice layers in early spring. The bottom communities exhibited a remarkably stable value for the photoadaptation parameter, E-k, of circa 25 mu mol photons m(-2) s(-1), Whereas pennate diatoms were most abundant in spring ice, the initial seeding event linked to ice melt was associated with flagellate species. Haptophyte species like Phaeocystis antarctica and prymnesiophytes like Pyramimonas spp. best sustained the transition from sea ice to seawater. Comparison with previous studies shows that the seeding patterns observed in Ryder Bay were characteristic over the wider sea-ice domain, Arctic and Antarctic. Over the course of this century, the WAP is predicted to experience continuing thinning and decline in sea-ice cover. For the near future, we expect that especially microalgal communities of haptophytes and chlorophytes will benefit from the changes, with yet unknown implications for carbon fluxes and higher trophic levels.Peer reviewe

Pigment Organization and Energy Transfer Dynamics in Isolated Photosystem I (PSI) Complexes from Arabidopsis thaliana Depleted of the PSI-G, PSI-K, PSI-L, or PSI-N Subunit

AbstractGreen plant photosystem I (PSI) consists of at least 18 different protein subunits. The roles of some of these protein subunits are not well known, in particular those that do not occur in the well characterized PSI complexes from cyanobacteria. We investigated the spectroscopic properties and excited-state dynamics of isolated PSI-200 particles from wild-type and mutant Arabidopsis thaliana plants devoid of the PSI-G, PSI-K, PSI-L, or PSI-N subunit. Pigment analysis and a comparison of the 5K absorption spectra of the various particles suggests that the PSI-L and PSI-H subunits together bind approximately five chlorophyll a molecules with absorption maxima near 688 and 667nm, that the PSI-G subunit binds approximately two red-shifted β-carotene molecules, that PSI-200 particles without PSI-K lack a part of the peripheral antenna, and that the PSI-N subunit does not bind pigments. Measurements of fluorescence decay kinetics at room temperature with picosecond time resolution revealed lifetimes of ∼0.6, 5, 15, 50, 120, and 5000ps in all particles. The 5- and 15-ps phases could, at least in part, be attributed to the excitation equilibration between bulk and red chlorophyll forms, though the 15-ps phase also contains a contribution from trapping by charge separation. The 50- and 120-ps phases predominantly reflect trapping by charge separation. We suggest that contributions from the core antenna dominate the 15-ps trapping phase, that those from the peripheral antenna proteins Lhca2 and Lhca3 dominate the 50-ps phase, and that those from Lhca1 and Lhca4 dominate the 120-ps phase. In the PSI-200 particles without PSI-K or PSI-G protein, more excitations are trapped in the 15-ps phase and less in 50- and 120-ps phases, which is in agreement with the notion that these subunits are involved in the interaction between the core and peripheral antenna proteins

Robust orthogonal parameterization of evolution strategy for adaptive laser pulse shaping

Many spectroscopic applications of femtosecond laser pulses require properly-shaped spectral phase profiles. The optimal phase profile can be programmed on the pulse by adaptive pulse shaping. A promising optimization algorithm for such adaptive experiments is evolution strategy (ES). Here, we report a four fold increase in the rate of convergence and ten percent increase in the final yield of the optimization, compared to the direct parameterization approach, by using a new version of ES in combination with Legendre polynomials and frequency-resolved detection. Such a fast learning rate is of paramount importance in spectroscopy for reducing the artifacts of laser drift, optical degradation, and precipitation

State-Dependent Modulation of Visual Evoked Potentials in a Rodent Genetic Model of Electroencephalographic Instability

Despite normal sleep timing and duration, Egr3-deficient (Egr3−/−) mice exhibit electroencephalographic (EEG) characteristics of reduced arousal, including elevated slow wave (1–4 Hz) activity during wakefulness. Here we show that these mice exhibit state-dependent instability in the EEG. Intermittent surges in EEG power were found in Egr3−/− mice during wakefulness and rapid eye movement sleep, most prominently in the beta (15–35 Hz) range compared to wild type (Egr3+/+) mice. Such surges did not coincide with sleep onset, as the surges were not associated with cessation of electromyographic tone. Cortical processing of sensory information by visual evoked responses (VEP) were found to vary as a function of vigilance state, being of higher magnitude during slow wave sleep (SWS) than wakefulness and rapid eye movement sleep. VEP responses were significantly larger during quiet wakefulness than active wakefulness, in both Egr3−/− mice and Egr3+/+ mice. EEG synchronization in the beta range, previously linked to the accumulation of sleep need over time, predicted VEP magnitude. Egr3−/− mice not only displayed elevated beta activity, but in quiet wake, this elevated beta activity coincides with an elevated evoked response similar to that of animals in SWS. These data confirm that (a) VEPs vary as a function of vigilance state, and (b) beta activity in the EEG is a predictor of state-dependent modulation of visual information processing. The phenotype of Egr3−/− mice indicates that Egr3 is a genetic regulator of these phenomena