Statistical sensitivity for detection of spatial and temporal patterns in rodent population densities.

A long-term monitoring program begun 1 year after the epidemic of hantavirus pulmonary syndrome in the U.S. Southwest tracked rodent density changes through time and among sites and related these changes to hantavirus infection rates in various small-mammal reservoir species and human disease outbreaks. We assessed the statistical sensitivity of the program's field design and tested for potential biases in population estimates due to unintended deaths of rodents. Analyzing data from two sites in New Mexico from 1994 to 1998, we found that for many species of Peromyscus, Reithrodontomys, Neotoma, Dipodomys, and Perognathus, the monitoring program detected species-specific spatial and temporal differences in rodent densities; trap-related deaths did not significantly affect long-term population estimates. The program also detected a short-term increase in rodent densities in the winter of 1997-98, demonstrating its usefulness in identifying conditions conducive to increased risk for human disease

Measurement, Decoherence and Chaos in Quantum Pinball

The effect of introducing measuring devices in a ``quantum pinball'' system is shown to lead to a chaotic evolution for the particle position as defined in Bohm's approach to Quantum Mechanics.Comment: Latex, uses ioplppt style, two figures. Also can be ftp'd anonymously from: ftp://zaphod.phys.port.ac.uk/pub/papers/paper2

Electronic spectra of polyatomic molecules with resolved individual rotational transitions

The density of rotational transitions for a polyatomic molecule is so large that in general many such transitions are hidden under the Doppler profile, this being a fundamental limit of conventional high resolution electronic spectroscopy. We present here the first Doppler-free cw two-photon spectrum of a polyatomic molecule. In the case of benzene, 400 lines are observed of which 300 are due to single rotational transitions, their spacing being weil below the Doppler profile. The resolution so achieved is 1.5 X 10'. Benzene is a prototype planar molecule taken to have D •• symmetry in the ground as weil as in the first excited state. From our ultra-high resolution results it is found that benzene in the excited SI state i8 a symmetrical rotor to a high degree. A negative inertial defect is found for the excited state. The origin of this inertial defect is discused

Spatio-temporal patterns in the Hantavirus infection

We present a model of the infection of Hantavirus in deer mouse, Peromyscus maniculatus, based on biological observations of the system in the North American Southwest. The results of the analysis shed light on relevant observations of the biological system, such as the sporadical disappearance of the infection, and the existence of foci or ``refugia'' that perform as reservoirs of the virus when environmental conditions are less than optimal.Comment: 6 pages, 5 inlined figures, RevTeX 4 forma

Rapid and accurate analysis of stem cell-derived extracellular vesicles with super resolution microscopy and live imaging

Extracellular vesicles (EVs) have prevalent roles in cancer biology and regenerative medicine. Conventional techniques for characterising EVs including electron microscopy (EM), nanoparticle tracking analysis (NTA) and tuneable resistive pulse sensing (TRPS), have been reported to produce high variability in particle count (EM) and poor sensitivity in detecting EVs below 50 nm in size (NTA and TRPS), making accurate and unbiased EV analysis technically challenging. This study introduces direct stochastic optical reconstruction microscopy (d-STORM) as an efficient and reliable characterisation approach for stem cell-derived EVs. Using a photo-switchable lipid dye, d-STORM imaging enabled rapid detection of EVs down to 20–30 nm in size with higher sensitivity and lower variability compared to EM, NTA and TRPS techniques. Imaging of EV uptake by live stem cells in culture further confirmed the potential of this approach for downstream cell biology applications and for the analysis of vesicle-based cell-cell communication

Back to the roots of "channel three"

Rotationally resolved fluorescence excitation and resonance enhanced multiphoton ionization (MPI) spectra of the 610130 one-photon band of benzene at the onset of ``channel three'' are reported. The fluorescence decay is monitored after rotationally selected excitation and a large variation of the nonradiative decay time (<1 to 6.8 ns) is found for the different rotational states at the vibrational excess energy of 3287 cm−1 in S1. The rotational structure of the fluorescence excitation spectrum and the MPI spectrum measured with delayed laser pulses differ considerably. All observed lines of the MPI spectrum were assigned and the rotational line structure can only be understood with a model which incorporates interference between different decay channels. Due to this interference, particular rotational states decay fairly slowly and give rise to lines in the spectrum while states with neighboring rotational quantum numbers decay rapidly and are therefore not found in the spectrum. The previously reported drastic increase of the electronic, nonradiative decay of benzene in this region of excess energy, which led to the postulation of ``channel three,'' cannot be confirmed. Instead, the optically excited rovibronic states are thought to be coupled to background states within S1 which are themselves broadened due to strong coupling to the highly excited S0 electronic state rather than due to an unknown (``channel three'') or isomerization process. The Journal of Chemical Physics is copyrighted by The American Institute of Physics

Effect of a Fundamental Motor Skills Intervention on Fundamental Motor Skill and Physical Activity in a Preschool Setting: A Cluster Randomized Controlled Trial

Purpose: To determine the effect of a 12-week fundamental motor skill (FMS) program on FMS and physical activity (PA) on preschool-aged children. Method: A cluster randomized controlled trial. The intervention (PhysicaL ActivitY and Fundamental Motor Skills in Pre-schoolers [PLAYFun] Program) was a 12-week games-based program, delivered directly to the children in childcare centers by exercise physiologists. Children in the control arm received the usual preschool curriculum. Outcomes included FMS competence (Test of Gross Motor Development-2) and PA (accelerometer) assessed at baseline, 12 weeks, and 24 weeks (12-wk postintervention). Results: Fifty children (mean age = 4.0 [0.6] y; 54% male) were recruited from 4 childcare centers. Two centers were randomized to PLAYFun and 2 centers were randomized to the waitlist control group. Children attended on average 2.0 (1.0) 40-minute sessions per week. The PLAYFun participants demonstrated significant increases in object control (P < .001) and total FMS (P = .010) competence at week 12, compared with controls in a group × time interaction. Girls, but not boys, in PLAYFun significantly increased moderate to vigorous PA after the intervention (P = .004). These increases were not maintained 12-week postcompletion of PLAYFun. Conclusions: The PLAYFun Program is effective at improving FMS competence in boys and girls and increasing PA in girls. However, improvements are not maintained when opportunities to practice are not sustained

Optical conductivity of filled skutterudites

A simple tight-binding model is constructed for the description of the electronic structure of some Ce-based filled skutterudite compounds showing an energy gap or pseudogap behavior. Assuming band-diagonal electron interactions on this tight-binding model, the optical conductivity spectrum is calculated by applying the second-order self-consistent perturbation theory to treat the electron correlation. The correlation effect is found to be of great importance on the description of the temperature dependence of the optical conductivity. The rapid disappearance of an optical gap with increasing temperature is obtained as observed in the optical experiment for Ce-based filled-skutterudite compounds.Comment: 6 pages, 7 figures, use jpsj2.cls, to appear in J. Phys. Soc. Jpn. Vol.73, No.10 (2004