Effect of pair interactions on transition probabilities between inactive and active states: achieving collective behaviour via pair interactions in social insects

To understand the evolution of well-organized social behaviour, we must first understand the mechanism by which collective behaviour establishes. In this study, the mechanisms of collective behaviour in a colony of social insects were studied in terms of the transition probability between active and inactive states, which is linked to mutual interactions. The active and inactive states of the social insects were statistically extracted from the velocity profiles. From the duration distributions of the two states, we found that 1) the durations of active and inactive states follow an exponential law, and 2) pair interactions increase the transition probability from inactive to active states. The regulation of the transition probability by paired interactions suggests that such interactions control the populations of active and inactive workers in the colony

Electron Spin Resonance Study on Irradiated Styrene in Crystalline and Glassy States

Styrene was irradiated at-196°C to give a five-line spectrum with a coupling constant of about 16 gauss. This is attributed to the free radical When a mixture of styrene and 2-methyltetrahydrofuran was irradiated, a broad singlet spectrum (total width 33 gauss) was superposed on the seven-line spectrum due to the methyltetrahydrofuran radical and no sharp singlet spectrum due to trapped electrons was observed. This broad singlet spectrum is thought to be due to styrene anion radicals. This spectrum was bleached by visible light and saturated appreciably with increasing microwave power. Similar phenomena were observed for a styrene-3-methylpentane mixture

Near-Infrared Imaging Survey of Faint Companions around Young Dwarfs in the Pleiades Cluster

We conducted a near-infrared imaging survey of 11 young dwarfs in the Pleiades cluster using the Subaru Telescope and the near-infrared coronagraph imager. We found 10 faint point sources, with magnitudes as faint as 20 mag in the K-band, around 7 dwarfs. Comparison with Spitzer archive images revealed that a pair of the faint sources around V 1171 Tau are very red in the infrared wavelengths, indicative of very low-mass young stellar objects. However, the results of our follow-up proper motion measurements implied that the central star and the faint sources do not share common proper motions, suggesting that they are not physically associated.Comment: 13 pages. Accepted for publication in Research in Astronomy and Astrophysic

In-gap state and effect of light illumination in CuIr2_2S4_4 probed by photoemission spectroscopy

We have studied disorder-induced in-gap states and effect of light illumination in the insulating phase of spinel-type CuIr$_2$S$_4$ using ultra-violet photoemission spectroscopy (UPS). The Ir$^{3+}$/Ir$^{4+}$ charge-ordered gap appears below the metal-insulator transition temperature. However, in the insulating phase, in-gap spectral features with $softgap$ are observed in UPS just below the Fermi level ($E_F$), corresponding to the variable range hopping transport observed in resistivity. The spectral weight at $E_F$ is not increased by light illumination, indicating that the Ir$^{4+}$-Ir$^{4+}$ dimer is very robust although the long-range octamer order would be destructed by the photo-excitation. Present results suggest that the Ir$^{4+}$-Ir$^{4+}$ bipolaronic hopping and disorder effects are responsible for the conductivity of CuIr$_2$S$_4$.Comment: 14 pages, 5 figure

Lithium in LP 944-20

The definitive version is available at www.blackwell-synergy.com. Copyright Blackwell Publishing DOI :10.1111/j.1365-2966.2007.12182.xPeer reviewe

Does the Elderly’s Number of Prescribed Medications across Months Matter? National Cohort versus Single-Center Cohort

AbstractObjectivesTo investigate the monthly number of prescribed medication (NPM) patterns among different elderly populations and the factors associated with monthly NPM changes.MethodsThis retrospective cohort study was conducted using the databases obtained from National Health Insurance Research Databases and a 2000-bed academic medical center in Taiwan (i.e., single-center cohort). We compared the monthly NPMs, demographic characteristics, disease states, and health care contacts among the National Health Insurance elderly cohorts in 2006 and 2007, and for those elderly in the national and single-center cohorts who had outpatient visits from November to October in 2006 to 2007 and 2007 to 2008, respectively. Generalized estimating equation analyses of repeated measures were performed for monthly NPMs.ResultsThe average monthly NPMs among the National Health Insurance elderly cohort was 2.33 in 2006 and 4.39 in 2007, respectively. After controlling for other factors, the increment in the proportion of monthly NPMs among the older elderly patients, in certain months and for those patients with hypertension and dyslipidemia, was statistically significant among the single-center cohort but was not observed in the national elderly cohort. The proportional changes decreased significantly among patients who made visits to emergency rooms and who were hospitalized during a 1-year period.ConclusionsThere was an incremental trend of monthly NPMs among the national cohort from 2006 to 2007. Although acute exacerbations and hospitalization might be the protecting factors of increasing monthly NPMs, more attention should be paid toward high-utilization patients with specific diseases during certain months for different elderly cohorts

Influences of ventricular pacing on hemodynamics, myocardial metabolism, and cardiac work efficiency: potential risks of rate-responsive ventricular pacing.

The influences of ventricular pacing at a rate of 70 beats/min (bpm) on the systemic and coronary hemodynamics, myocardial metabolism, and cardiac work efficiency were evaluated in five patients with bradycardia. The results were compared to those obtained in six normal subjects at rest. In order to elucidate the effects of a relatively high rate of ventricular pacing, cardiovascular and metabolic variables were also obtained at 120 bpm in the normal subjects. It was observed that the patients eventually benefited from ventricular pacing at a rate of 70 bpm and improved in systemic hemodynamics. Although coronary hemodynamics and myocardial metabolism were accelerated, the cardiac work efficiency was not improved. A pacing rate of 120 bpm in the normal subjects did not appear to accelerate systemic hemodynamics, but adverse accelerations of coronary hemodynamics and myocardial metabolism were observed, and the cardiac work efficiency was remarkably reduced as a result. Our observations indicated that the coronary reserve capacity was very important for ventricular pacing, and suggested that an undue increment of the pacing rate not only might be meaningless but also might induce ischemic angina. Therefore, we should be cautious in using a rate-responsive pacing mode, particularly in determination of the upper limit of pacing rates, although many benefits with this pacing mode have recently been advocated.</p