Single-photon generation and simultaneous observation of wave and particle properties

We describe an experiment that generates single photons on demand and measures properties accounted to both particle- and wave-like features of light. The measurement is performed by exploiting data that are sampled simultaneously in a single experimental run.Comment: The following article has been submitted to Proceedings of "Foundations of probability and physics-3", Vaxjo, Sweden 2004. After it is published, it will be found at http://proceedings.aip.org/ . 1 Reference was added in version

A folded-sandwich polarization-entangled two-color photon pair source with large tuning capability for applications in hybrid quantum architectures

We demonstrate a two-color entangled pho ton pair source which can be adapted easily to a wide range of wavelengths combinations. A Fresnel rhomb as a geometrical quarter-wave plate and a versatile combination of compensation crystals are key components of the source. Entanglement of two photons at the Cs D1 line (894.3 nm) and at the telecom O-band (1313.1 nm) with a fidelity of $F = 0.753 \pm 0.021$ is demonstrated and improvements of the setup are discussed

Delayed Emergence of Trachykele blondeli blondeli (Coleoptera: Buprestidae)

Prolonged emergence of Trachykele blondeli blondeli Marseul (Coleoptera: Buprestidae) is reported from kiln-dried and subsequently painted wood in this report. The specimen emergence is a new record for Florida. Because the specimen did not emerge from host plant material grown in Florida, it is likely that its origin was exterior to Florida. Because of delayed and prolonged emergence capability in Buprestidae, as well as specimen survival of wood preservation processes like kiln drying, the current report does indicate a concern for redistribution of non-indigenous buprestid species to new areas

Small RNAs are trafficked from the epididymis to developing mammalian sperm [preprint]

RNAs present in mature mammalian sperm are delivered to the zygote at fertilization, where they have the potential to affect early development. The biogenesis of the small RNA payload of mature sperm is therefore of great interest, as it may be a target of signaling pathways linking paternal conditions to offspring phenotype. Recent studies have suggested the surprising hypothesis that the small RNA payload carried by mature sperm may include RNAs that were not synthesized during testicular spermatogenesis, but that are instead delivered to sperm during the process of post-testicular maturation in the epididymis. To further test this hypothesis, we characterized small RNA dynamics during testicular and post-testicular germ cell maturation in mice. We show that purified testicular germ cell populations, including mature testicular spermatozoa, carry extremely low levels of tRNA fragments (tRFs), and that tRFs become highly abundant only after sperm have entered the epididiymis. The process of small RNA delivery to sperm can be recapitulated in vitro, as caput epididymosomes deliver small RNAs including tRFs and microRNAs to mature testicular spermatozoa. Finally, to definitively identify the tissue of origin for small RNAs in sperm, we carried out tissue-specific metabolic labeling of RNAs in intact mice, finding that mature sperm carry small RNAs that were originally synthesized in the somatic cells of the epididymis. Taken together, our data demonstrates that soma-germline small RNA transfer occurs in male mammals, most likely via vesicular transport from the epididymis to maturing sperm

Body physique and heart rate variability determine the occurrence of stair-step artefacts in 64-slice CT coronary angiography with prospective ECG-triggering

The purpose of this study was to describe and characterize the frequency and extent of stair-step artefacts in computed tomography coronary angiography (CTCA) with prospective electrocardiogram (ECG)-triggering and to identify their determinants. One hundred and forty three consecutive patients (55 women, mean age 57 ± 13years) underwent 64-slice CTCA using prospective ECG-triggering. Occurrence of stair-step artefacts in CTCA of the thoracic wall and the coronary arteries was determined and maximum offset was measured. If stair-step artefacts occurred in both cases, a difference between thoracic wall and coronary artery offset of 0.6mm or greater was attributed to additional motion of the heart. Mean effective radiation dose was 2.1 ± 0.7mSv (range 1.0-3.5mSv). Eighty-nine patients (62%) had stair-step artefacts in CTCA of the coronary arteries (mean offset of 1.7 ± 1.1mm), while only 77 patients had thoracic wall stair-step artefacts (mean offset of 1.0 ± 0.3mm; significantly different, P < 0.001). Stair-step artefacts in CTCA of the thoracic wall were determined by BMI and weight (P < 0.01), while artefacts in CTCA of the coronary arteries were associated with heart rate variability (P < 0.05). Stair-step artefacts in CTCA with prospective ECG-triggering are determined by (a) motion of the entire patient during table travel, particularly in large patients and (b) by motion of the heart, particularly when heart rates are variabl

Determinants of vessel contrast in BMI-adapted low dose CT coronary angiography with prospective ECG-triggering

We evaluated the determinants of vessel contrast in prospectively ECG-triggered CT coronary angiography (CTCA). Seventy patients underwent low-dose CTCA using Body Mass Index (BMI)-adapted tube parameters and a fixed contrast material bolus. Contrast to noise ratio (CNR) was calculated from contrast (between coronaries and perivascular tissue) and image noise (standard deviation of aortic attenuation). Cardiac output (CO) was calculated from gated 99mTc-tetrofosmin-SPECT. Mean radiation dose was 2.13±0.69mSv. Image noise was not affected by BMI (r=0.1, P=0.36), while CNR was inversely related to body surface area (BSA) (r=−0.5, P<0.001) and CO (r=−0.45, P<0.001). After successfully overcoming the impact of BMI on image noise by adapting tube parameters, CNR mainly depends on coronary vessel contrast. The latter reflects the dilution of the contrast material by blood volume and CO, which are both correlated to BSA. Therefore, BSA adapted contrast administration may help to compensate for this effec