Bragg Spectroscopy of ultracold atoms loaded in an optical lattice

We study Bragg spectroscopy of ultra-cold atoms in one-dimensional optical lattices as a method for probing the excitation spectrum in the Mott insulator phase, in particular the one particle-hole excitation band. Within the framework of perturbation theory we obtain an analytical expression for the dynamic structure factor $S(q,\omega)$ and use it to calculate the imparted energy which has shown to be a relevant observable in recent experiments. We test the accuracy of our approximations by comparing them with numerically exact solutions of the Bose-Hubbard model in restricted cases and establish the limits of validity of our linear response analysis. Finally we show that when the system is deep in the Mott insulator regime, its response to the Bragg perturbation is temperature dependent. We suggest that this dependence might be used as a tool to probe temperatures of order of the Mott gap.Comment: 4 pages, 3 figure

A molecular timescale of eukaryote evolution and the rise of complex multicellular life

BACKGROUND: The pattern and timing of the rise in complex multicellular life during Earth's history has not been established. Great disparity persists between the pattern suggested by the fossil record and that estimated by molecular clocks, especially for plants, animals, fungi, and the deepest branches of the eukaryote tree. Here, we used all available protein sequence data and molecular clock methods to place constraints on the increase in complexity through time. RESULTS: Our phylogenetic analyses revealed that (i) animals are more closely related to fungi than to plants, (ii) red algae are closer to plants than to animals or fungi, (iii) choanoflagellates are closer to animals than to fungi or plants, (iv) diplomonads, euglenozoans, and alveolates each are basal to plants+animals+fungi, and (v) diplomonads are basal to other eukaryotes (including alveolates and euglenozoans). Divergence times were estimated from global and local clock methods using 20–188 proteins per node, with data treated separately (multigene) and concatenated (supergene). Different time estimation methods yielded similar results (within 5%): vertebrate-arthropod (964 million years ago, Ma), Cnidaria-Bilateria (1,298 Ma), Porifera-Eumetozoa (1,351 Ma), Pyrenomycetes-Plectomycetes (551 Ma), Candida-Saccharomyces (723 Ma), Hemiascomycetes-filamentous Ascomycota (982 Ma), Basidiomycota-Ascomycota (968 Ma), Mucorales-Basidiomycota (947 Ma), Fungi-Animalia (1,513 Ma), mosses-vascular plants (707 Ma), Chlorophyta-Tracheophyta (968 Ma), Rhodophyta-Chlorophyta+Embryophyta (1,428 Ma), Plantae-Animalia (1,609 Ma), Alveolata-plants+animals+fungi (1,973 Ma), Euglenozoa-plants+animals+fungi (1,961 Ma), and Giardia-plants+animals+fungi (2,309 Ma). By extrapolation, mitochondria arose approximately 2300-1800 Ma and plastids arose 1600-1500 Ma. Estimates of the maximum number of cell types of common ancestors, combined with divergence times, showed an increase from two cell types at 2500 Ma to ~10 types at 1500 Ma and 50 cell types at ~1000 Ma. CONCLUSIONS: The results suggest that oxygen levels in the environment, and the ability of eukaryotes to extract energy from oxygen, as well as produce oxygen, were key factors in the rise of complex multicellular life. Mitochondria and organisms with more than 2–3 cell types appeared soon after the initial increase in oxygen levels at 2300 Ma. The addition of plastids at 1500 Ma, allowing eukaryotes to produce oxygen, preceded the major rise in complexity

Introspection confidence predicts EEG decoding of self-generated thoughts and meta-awareness

The neurophysiological bases of mind wandering (MW) – an experiential state wherein attention is disengaged from the external environment in favour of internal thoughts, and state meta-awareness are poorly understood. In parallel, the relationship between introspection confidence in experiential state judgements and neural representations remains unclear. Here, we recorded EEG whilst participants completed a listening task within which they made experiential state judgments and rated their confidence. Alpha power was reliably greater during MW episodes, with unaware MW further associated with greater delta and theta power. Multivariate pattern classification analysis revealed that MW, and meta-awareness can be decoded from the distribution of power in these three frequency bands. Critically, we show that individual decoding accuracies positively correlate with introspection confidence. Our results reaffirm the role of alpha oscillations in MW, implicate lower frequencies in meta-awareness, and are consistent with the proposal that introspection confidence indexes neurophysiological discriminability of representational states

Cardiovascular disease prevention by sports: myth or reality?

Low levels of physical activity and fitness substantially increase risk of several chronic diseases, reduce longevity, and lead to loss of function. The strength and relation of inactivity to health problems and the high prevalence of sedentary habits in most countries of the world make lack of exercise a major public health problem. Fortunately, there is now good consensus regarding public health recommendations for physical activity from many important medical, scientific, and public health organizations. Recent research on physical activity interventions provides additional approaches to helping sedentary adults become more physically active

Antiplasmodials soulattrolide derivatives from Calophyllum brasiliense and its mechanism of activity

Parasitic diseases such as malaria, leishmaniasis, trypanosomia-sis, and schistosomiasis are just one of the main causes of diseaseand death in the world today (WHO, 2016). In 2016, 91 countriesreported a total of 216 million cases of malaria, which representsan increase to 5 million cases in relation to the previous year, with15 countries holding 80% of the global burden of malaria. The totalnumber of deaths worldwide reached 445.000, similar to thatreported in 2015 (WHO, 2017; Chin, 2001; Newman et al., 2016),so there is an urgent need to discover new, safe and effective drugsfor the prophylaxis and treatment of malaria, mainly due to thedevelopment of resistance ofPlasmodium falciparum, the mostlethal Plasmodium species to chloroquine and other antimalarialdrugs. Few alternative drugs are in development and urgent mea-sures are needed to identify new types of antimalarial agents,many of which have originated from natural products (Olumese,2015; Leach, 2001).Clusiaceaeis one of the families of plants inwhich compounds with antimalarial activity have been found, suchas xanthones and derivatives of acylphloroglucinol. Since the genusCalophyllumis a potential source of secondary metabolites and itsspecies are little explored in the field of malaria, their explorationis justified as a phytotherapeutic alternative in the treatment ofmalaria (Hay et al., 2004; Chanphen et al., 1998; Pierson et al., 2010; Guillaume et al., 2009). This paper reports the isolation ofsoulattrolide (1) fromC. brasiliense. the preparation of eight newderivatives (2–9) by hemi-synthesis and the bioactivity studiesthereof

Effects of Parent Implemented Visual Schedule Routines for African American Children with ASD in Low-Income Home Settings

Low-income, minority families are underrepresented in the literature on parent training for school-aged children with autism spectrum disorder (ASD). Although the use of visual supports, such as visual schedules, is considered to be an evidence-based practice for children with ASD in school, it is not known whether this strategy is effective for minority, low-income families when implemented by the parent in the home setting. This study used a multiple-baseline across routines design replicated across two African American child-mother dyads to examine the effects of a parent-implemented visual schedule procedure on child independent schedule use and between-activity transitions. Parent participants were trained to implement a visual schedule intervention during home routines. Although a functional relation was demonstrated across routines for one mother-child dyad, results varied across participants, highlighting the importance of treatment fidelity. Implications for future research, including the challenges involved in parent-implemented interventions in low-income settings for minority children with ASD, are addressed