Effects of interval between fusion and activation, cytochalasin B treatment, and number of transferred embryos, on cloning efficiency in goats

To improve the efficiency of somatic cell nuclear transfer (SCNT) in goats, we evaluated the effects of the interval between fusion and activation (1 to 5 h), cytochalasin B (CB) treatment after electrofusion, and the number of transferred embryos on the in vivo and in vitro development of cloned caprine embryos. The majority of the reconstructed embryos had condensed chromosomes and metaphase-like chromosomes at 2 and 3 h after fusion; cleavage and blastocyst rates from those two groups were higher (P < 0.05) than those of embryos activated 1, 4, or 5 h after fusion. Treatment with CB between fusion and activation improved in vitro and in vivo development of nuclear transfer (NT) goat embryos by reducing the fragmentation rate (P < 0.05). Although there were no significant differences in NT efficiency, pregnancy rate and kids born per recipient were increased by transfer of 20 or 30 embryos per recipient compared with 10 embryos. We concluded that CB treatment for 2 to 3 h between fusion and activation was an efficient method for generating cloned goats by somatic cell NT. In addition, increasing the number of embryos transferred to each recipient resulted in more live offspring from fewer recipients.

Optical precursor of a single photon

We report the direct observation of optical precursors of heralded single photons with step- and square-modulated wave packets passing through cold atoms. Using electromagnetically induced transparency and the slow-light effect, we separate the single-photon precursor, which always travels at the speed of light in vacuum, from its delayed main wave packet. In the two-level superluminal medium, our result suggests that the causality holds for a single photon.

Electro-optical tunable time delay and advance in a silicon feedback-microring resonator

We report the demonstration of electro-optical tunable time delay and advance using a silicon feedback-microring resonator integrated with p-i-n diodes. By controlling the feedback and round-trip phase shifts through the carrier-injection-based free-carrier dispersion effect, we obtain a large dynamic time tuning range (-88 ps to 110 ps) upon dc bias voltage change in the range of few tens of millivolts at a given resonance wavelength. We also demonstrate tunable time delay and advance at different resonance wavelengths within 0.76 nm wavelength range.

Generation of narrow-band hyperentangled nondegenerate paired photons

We report the generation of nondegenerate narrow-bandwidth paired photons with time-frequency and polarization entanglements from laser cooled atoms. We observe the two-photon interference caused by Rabi splitting with a coherence time of about 30 ns and a visibility of 81.8% which verifies the time-frequency entanglement of the paired photons. The polarization entanglement is confirmed by polarization correlation measurements which exhibit a visibility of 89.5% and characterized by quantum-state tomography with a fidelity of 90.8%. Taking into account the transmission losses and duty cycle, we estimate that the system generates hyperentangled paired photons into opposing single-mode fibers at a rate of 320 pairs per second.

Evaluation of patient self-management outcomes in health care: a systematic review

BACKGROUND

The importance of self-management and its intervention for improving the ability and skill of self-management has been discussed in literatures. It is, however, unclear how to choose the fitted, objective and accurate evaluation system when assessing the outcome.

AIM

The aim of this article was to establish a general evaluation system for skill and ability of self-management in chronic diseases through systematic review on different evaluation indicators and scales.

METHOD

A systematic search of six electronic databases was conducted. Two authors independently reviewed each qualified study for relevance and significance. Subsequently, main evaluation indicators and scales were identified and categorized into themes and sub-themes.

RESULTS

Nineteen articles were identified in this review. Among them, six main evaluation indicators of self-management, including frequently used scales, were extracted and tabulated. Self-efficacy, health behaviour/attitude, health status, health service utilization, quality of life and psychological indicators were the main indicators in evaluating self-management outcome, and they could be used alone or in combination flexibly according to the different goals of programmes.

CONCLUSION

Accurate evaluation of skill and ability of self-management is crucial not only in baseline data collection but also in proving the effectiveness of intervention. The outcomes of this study provide future researchers or caregivers with a better understanding and a series of good choices in self-management outcome evaluation.

Stacked optical precursors from amplitude and phase modulations

We report the generation of stacked optical precursors from a laser beam whose amplitude or phase is modulated by sequenced on-off step waveforms. Making use of the constructive interference between the precursors produced from different steps, as well as the main field, we generate optical transient pulses having peak powers of eight times the input power with electromagnetically induced transparency in laser-cooled atoms.

Two-photon free-induction decay with electromagnetically induced transparency

We report the observation of coherent two-photon free-induction decay (FID) in a three-level Lambda system excited by a low-intensity square-modulated laser pulse. Using electromagnetically induced transparency in an Rb85 cold atomic cloud, for what we believe to be the first time, we observe FID signals with coherence time exceeding the relevant atomic excited-state natural lifetime. Because of the on-resonance enhancement, the two-photon FID signal can be observed at the falling edge without using heterodyne means.

Shaping biphoton temporal waveforms with modulated classical fields

We experimentally demonstrate a technique for shaping the temporal quantum waveform of narrow-band biphotons generated in a cold atomic ensemble via four-wave mixing by periodically modulating the two input classical lasers. We show that it is possible to generate nonclassical paired photons with a predesigned shape of the correlation function.

Slow-light-induced interference with stacked optical precursors for square input pulses

We theoretically study the stacked optical transients generated from a series of square pulses passing through a cold atomic ensemble. Using the hybrid analysis and fast Fourier transform, we identify the stacked coherent transients [Europhys. Lett. 4, 47 (1987)] as optical precursors. With slow-light and electromagnetically induced transparency, we obtain nearly 700% transmitted intensity at the transient spikes resulting from the interference between the delayed main field and the stacked optical precursors.

Optical precursors with electromagnetically induced transparency in cold atoms

We report the observation of Sommerfeld-Brillouin optical precursors generated from a long square-modulated laser pulse propagating through a cold atomic ensemble with electromagnetically induced transparency. The optical depth (alpha(0)L) of the medium can be varied from 0 up to 50. We demonstrated that the step-on rising and step-off falling edges propagate with the speed of light in vacuum without a slow light effect. At high alpha(0)L, the precursor is separated from the delayed main pulse at the rising edge, while at the falling edge, we observe damped oscillatory structures resulting from the interference between the precursor and main field.

Influence of rumen escape starch on pancreatic exocrine secretion of goats

The objective of the experiment was to evaluate the effect of rumen escape starch (RES), accomplished by altering dietary starch concentrations on pancreatic exocrine secretion of goats. Four goats (36.8 +/- 3.2 kg) with common bile duct re-entrant and duodenal catheters were used in a 4 x 4 Latin square. Goats were fed diets containing 20%, 30%, 40% and 50% starch. Periods consisted of 10 day adaptation followed by 3 day of sample collection. Juice was collected in 1-h fractions continuously for 72 h. Total juice secreted was recorded, and 3% sub samples were retained to form a composite sample. The remaining fluid was returned to the duodenum. Juice composite samples were analyzed for activities of alpha-amylase, trypsin, chymotrypsin and lipase. Secretion of pancreatic alpha-amylase was lower (p < 0.05) when comparing lambs fed 20% starch diet with 30%, 40% and 50% starch diets. Lipase secretion was greater (p < 0.05) in lambs fed 40% starch diet compared with the other diets. Total secretion of juice, trypsin and chymotrypin was not affected (p > 0.05) by dietary starch concentration. Rumen escape starch increased with increasing dietary starch concentration (p < 0.05). Regression analysis showed that increasing RES results in a quadratic increase (p < 0.05) in pancreatic alpha-amylase and lipase secretion, and the secretion of alpha-amylase and lipase is maximum when RES is 113 and 83 g/day respectively. These results suggest that optimal RES for pancreatic secretion of alpha-amylase and lipase is 80-110 g/day in adult goats.

First measurement of the neutron beta asymmetry with ultracold neutrons

We report the first measurement of an angular correlation parameter in neutron beta decay using polarized ultracold neutrons (UCN). We utilize UCN with energies below about 200 neV, which we guide and store for approximately 30 s in a Cu decay volume. The interaction of the neutron magnetic dipole moment with a static 7 T field external to the decay volume provides a 420 neV potential energy barrier to the spin state parallel to the field, polarizing the UCN before they pass through an adiabatic fast passage spin flipper and enter a decay volume, situated within a 1 T field in a 2x2pi solenoidal spectrometer. We determine a value for the beta-asymmetry parameter A_{0}=-0.1138+/-0.0046+/-0.0021.

Observation of optical precursors at the biphoton level

We describe the observation of a sharp leading-edge spike in a biphoton wave packet that is produced using slow light and measured by two-photon correlation. Using the stationary-phase approximation we characterize this spike as a Sommerfeld-Brillouin precursor resulting from the interference of low- and high-frequency spectral components.

Electro-optic modulation of single photons

We use the Stokes photon of a biphoton pair to set the time origin for electro-optic modulation of the wave function of the anti-Stokes photon thereby allowing arbitrary phase and amplitude modulation. We demonstrate conditional single-photon wave functions composed of several pulses, or instead, having Gaussian or exponential shapes.

Subnatural linewidth biphotons with controllable temporal length

This Letter describes the generation of biphotons with a temporal length that can be varied over the range of 50-900 ns, with an estimated subnatural linewidth as small as 0.75 MHz. We make use of electromagnetically induced transparency and slow light in a two-dimensional magneto-optical trap with an optical depth as high as 62. We report a sharp leading edge spike that is a Sommerfeld-Brillouin precursor, as observed at the biphoton level.