Spinor dynamics in an antiferromagnetic spin-1 thermal Bose gas

We present experimental observations of coherent spin-population oscillations in a cold thermal, Bose gas of spin-1 sodium-23 atoms. The population oscillations in a multi-spatial-mode thermal gas have the same behavior as those observed in a single-spatial-mode antiferromagnetic spinor Bose Einstein condensate. We demonstrate this by showing that the two situations are described by the same dynamical equations, with a factor of two change in the spin-dependent interaction coefficient, which results from the change to particles with distinguishable momentum states in the thermal gas. We compare this theory to the measured spin population evolution after times up to a few hundreds of ms, finding quantitative agreement with the amplitude and period. We also measure the damping time of the oscillations as a function of magnetic field.Comment: 5 pages, 3 figure

The Composition of Human Milk and Infant Faecal Microbiota Over the First Three Months of Life: A Pilot Study

peer-reviewedHuman milk contains a diverse array of bioactives and is also a source of bacteria for the developing infant gut. The aim of this study was to characterize the bacterial communities in human milk and infant faeces over the first 3 months of life, in 10 mother-infant pairs. The presence of viable Bifidobacterium and Lactobacillus in human milk was also evaluated. MiSeq sequencing revealed a large diversity of the human milk microbiota, identifying over 207 bacterial genera in milk samples. The phyla Proteobacteria and Firmicutes and the genera Pseudomonas, Staphylococcus and Streptococcus were the predominant bacterial groups. A core of 12 genera represented 81% of the microbiota relative abundance in milk samples at week 1, 3 and 6, decreasing to 73% at week 12. Genera shared between infant faeces and human milk samples accounted for 70–88% of the total relative abundance in infant faecal samples, supporting the hypothesis of vertical transfer of bacteria from milk to the infant gut. In addition, identical strains of Bifidobacterium breve and Lactobacillus plantarum were isolated from the milk and faeces of one mother-infant pair. Vertical transfer of bacteria via breastfeeding may contribute to the initial establishment of the microbiota in the developing infant intestine

Deconstructing and Operationalizing Interactivity: An Online Advertising Perspective

In an online advertising context this empirical study examines the influence of the interface characteristic Interactivity on important user perceptions and their intention to use a website. Results indicate that social presence and telepresence are significant predictors of attitude toward online advertisements, satisfaction with online advertisements, and subsequent intentions to use a host website. Also indicated by this study is the significant influence of interactivity, as well as consumer involvement and the interaction between these two variables. The outcomes of this study offer preliminary insight into the conceptualization and affect of interface characteristics, such as interactivity, in online advertising

A non-circadian role for clock-genes in sleep homeostasis:a strain comparison

BACKGROUND: We have previously reported that the expression of circadian clock-genes increases in the cerebral cortex after sleep deprivation (SD) and that the sleep rebound following SD is attenuated in mice deficient for one or more clock-genes. We hypothesized that besides generating circadian rhythms, clock-genes also play a role in the homeostatic regulation of sleep. Here we follow the time course of the forebrain changes in the expression of the clock-genes period (per)-1, per2, and of the clock-controlled gene albumin D-binding protein (dbp) during a 6 h SD and subsequent recovery sleep in three inbred strains of mice for which the homeostatic sleep rebound following SD differs. We reasoned that if clock genes are functionally implicated in sleep homeostasis then the SD-induced changes in gene expression should vary according to the genotypic differences in the sleep rebound. RESULTS: In all three strains per expression was increased when animals were kept awake but the rate of increase during the SD as well as the relative increase in per after 6 h SD were highest in the strain for which the sleep rebound was smallest; i.e., DBA/2J (D2). Moreover, whereas in the other two strains per1 and per2 reverted to control levels with recovery sleep, per2 expression specifically, remained elevated in D2 mice. dbp expression increased during the light period both during baseline and during SD although levels were reduced during the latter condition compared to baseline. In contrast to per2, dbp expression reverted to control levels with recovery sleep in D2 only, whereas in the two other strains expression remained decreased. CONCLUSION: These findings support and extend our previous findings that clock genes in the forebrain are implicated in the homeostatic regulation of sleep and suggest that sustained, high levels of per2 expression may negatively impact recovery sleep

Multicenter Evaluation of the QIAstat-Dx Respiratory Panel for the Detection of Viruses and Bacteria in Nasopharyngeal Swab Specimens

The QIAstat-Dx Respiratory Panel (QIAstat-Dx RP) is a multiplex in vitro diagnostic test for the qualitative detection of 20 pathogens directly from nasopharyngeal swab (NPS) specimens. The assay is performed using a simple sample-to-answer platform with results available in approximately 69 min. The pathogens identified are adenovirus, coronavirus 229E, coronavirus HKU1, coronavirus NL63, coronavirus OC43, human metapneumovirus A and B, influenza A, influenza A H1, influenza A H3, influenza A H1N1/2009, influenza B, parainfluenza virus 1, parainfluenza virus 2, parainfluenza virus 3, parainfluenza virus 4, rhinovirus/enterovirus, respiratory syncytial virus A and B, Bordetella pertussis, Chlamydophila pneumoniae, and Mycoplasma pneumoniae. This multicenter evaluation provides data obtained from 1,994 prospectively collected and 310 retrospectively collected (archived) NPS specimens with performance compared to that of the BioFire FilmArray Respiratory Panel, version 1.7. The overall percent agreement between QIAstat-Dx RP and the comparator testing was 99.5%. In the prospective cohort, the QIAstat-Dx RP demonstrated a positive percent agreement of 94.0% or greater for the detection of all but four analytes: coronaviruses 229E, NL63, and OC43 and rhinovirus/enterovirus. The test also demonstrated a negative percent agreement of ≥97.9% for all analytes. The QIAstat-Dx RP is a robust and accurate assay for rapid, comprehensive testing for respiratory pathogens

An analysis of the evolving comoving number density of galaxies in hydrodynamical simulations

The cumulative comoving number-density of galaxies as a function of stellar mass or central velocity dispersion is commonly used to link galaxy populations across different epochs. By assuming that galaxies preserve their number-density in time, one can infer the evolution of their properties, such as masses, sizes, and morphologies. However, this assumption does not hold in the presence of galaxy mergers or when rank ordering is broken owing to variable stellar growth rates. We present an analysis of the evolving comoving number density of galaxy populations found in the Illustris cosmological hydrodynamical simulation focused on the redshift range $0\leq z \leq 3$. Our primary results are as follows: 1) The inferred average stellar mass evolution obtained via a constant comoving number density assumption is systematically biased compared to the merger tree results at the factor of $\sim$2(4) level when tracking galaxies from redshift $z=0$ out to redshift $z=2(3)$; 2) The median number density evolution for galaxy populations tracked forward in time is shallower than for galaxy populations tracked backward in time; 3) A similar evolution in the median number density of tracked galaxy populations is found regardless of whether number density is assigned via stellar mass, stellar velocity dispersion, or dark matter halo mass; 4) Explicit tracking reveals a large diversity in galaxies' assembly histories that cannot be captured by constant number-density analyses; 5) The significant scatter in galaxy linking methods is only marginally reduced by considering a number of additional physical and observable galaxy properties as realized in our simulation. We provide fits for the forward and backward median evolution in stellar mass and number density and discuss implications of our analysis for interpreting multi-epoch galaxy property observations.Comment: 18 pages, 11 figures, submitted to MNRAS, comments welcom

Green Bank Telescope and Swift X-ray Telescope Observations of the Galactic Center Radio Magnetar SGR J1745-2900

We present results from eight months of Green Bank Telescope 8.7-GHz observations and nearly 18 months Swift X-ray telescope observations of the radio magnetar SGR J1745-2900, which is located 2.4" from Sgr A*. We tracked the magnetar's radio flux density, polarization properties, pulse profile evolution, rotation, and single-pulse behavior. We identified two main periods of activity in SGR J1745-2900. The first is characterized by approximately 5.5 months of relatively stable evolution in radio flux density, rotation, and profile shape, while in the second these properties varied substantially. Specifically, a third profile component emerged and the radio flux increased on average, but also became more variable. Bright single pulses are visible and are well described by a log-normal energy distribution at low to moderate energies, but with an excess at high energies. The 2-10 keV flux has decayed steadily since the initial X-ray outburst, in contrast with the radio flux. Our timing analysis includes Green Bank Telescope, Swift, and NuSTAR data. When we include the X-ray data in our analyses, we find that SGR J1745-2900 exhibited a level of timing noise unprecedented in a radio magnetar, though an analysis of only the radio data indicates timing noise at a level similar to that observed in other radio magnetars. We conclude that, while SGR J1745-2900 is similar to other radio magnetars in many regards, it differs by having experienced a period of relative stability in the radio band that now appears to have ended, while the X-ray properties have evolved independently.Comment: Submitted to ApJ; 10 pages (emulateapj style), 6 figures, 1 tabl