2,918 research outputs found
Adaptive homodyne measurement of optical phase
We present an experimental demonstration of the power of real-time feedback
in quantum metrology, confirming a theoretical prediction by Wiseman regarding
the superior performance of an adaptive homodyne technique for single-shot
measurement of optical phase. For phase measurements performed on weak coherent
states with no prior knowledge of the signal phase, we show that the variance
of adaptive homodyne estimation approaches closer to the fundamental quantum
uncertainty limit than any previously demonstrated technique. Our results
underscore the importance of real-time feedback for reaching quantum
performance limits in coherent telecommunication, precision measurement and
information processing.Comment: RevTex4, color PDF figures (separate files), submitted to PR
Preliminary Observations on the Effects In Vivo and In Vitro of Low Dose Laser on the Epithelia of the Bladder, Trachea and Tongue of the Mouse
The effects of low dose CW laser were studied by in vivo and in vitro systems. The experimental tissues that were used included bladders, tracheas and tongues as experimental tissues. Buddings (round surface projections) from the transitional epithelium of bladder were frequently observed 3 days after laser treatment in both in vivo and in vitro systems. The trachea and tongue were less affected. In both the in vivo and in vitro systems, some epithelial cells of the trachea showed decreased microvilli and cilia 3 days after treatment whereas the epithelial cells of the tongue revealed no response to laser treatment in both systems. Low dose laser, however, appeared to promote the rate of healing of experimental tongue ulcer: healing was about 1 day earlier in the laser treated than non-treated animals and vessel infiltration and epithelialization were detected earlier in the treated
Investigating Mainstreaming Strategies of Hot Cryptocurrencies-wallet
The proliferation of cryptocurrencies in recent years has prompted the launching of many hot cryptocurrencies-wallets (known as hot crypto-wallet , permanently connected to the Internet) services to facilitate the management of cryptocurrencies assets. However, the dark side of cryptocurrencies, such as possible illegal activities and difficulties of key management, may hinder the broader cryptocurrency adoption. Therefore, some hot crypto-wallet services providers have adopted different measures to mainstream their services. Using a qualitative approach, we identified four mainstreaming strategies of hot crypto-wallet services, which may hint at some practical implications for hot cryptowallet service providers
Stimulation of Collagen Formation in the Intestinal Anastomosis by Low Dose He-Ne Laser
The effect of low dose He-Ne laser on the healing of intestinal anastomosis was studied in the albino rat. A small piece of jejunum was removed from each rat and the ends sutured back with a simple interrupted pattern. In the experimental animal, the anastomosis was Irradiated through an optic fiber with a He-Ne laser (1 mW) for 15 minutes whereas in the control animal, the anastomosis was not irradiated. The differences between the two groups were compared by histology, transmission electron microscopy, scanning electron microscopy and autoradiography 3 and 7 days after operation. The laser treated experimental animals demonstrated thicker collagen fibers and an increased quantity of collagen at the junction of the anastomosis compared to control animals. Increased uptake of labelled proline was also evident in the laser treated animals. These observations all point to a possible enhancement of collagen synthesis triggered by laser irradiation
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Orthographic effects on L2 production and L2 proficiency in ESL learners with non-alphabetic and orthographically opaque L1
This study examined the role of first language (L1) transparency in intra-orthographic effects on second language (L2) pronunciation by studying L2 learners with a non-alphabetic and orthographically opaque L1 and an alphabetic L2. Relations between orthographic effects, phonological awareness, and L2 proficiency were examined. Fifty-four Cantonese-speaking English as a second language (ESL) learners participated in Experiment 1 with orthographic effect tasks (homophone and silent-letter read-aloud) and phonological awareness tasks. Thirty Cantonese-speaking and 30 Mandarin-speaking ESL learners participated in Experiment 2 with orthographic effect tasks and an L2 proficiency task. The L2 pronunciation of Cantonese and Mandarin participants was subjected to intra-orthographic effects. Phonological awareness and L2 proficiency were associated with less orthographic effects on L2 pronunciation in Cantonese participants. Mandarin participants did not subject to more orthographic effects than Cantonese participants when controlling L2 proficiency, implying that shared alphabetic scripts between Pinyin and English did not interfere with L2 production. Overall, transferring the L1 reading strategy that relies on orthography to decode phonology to L2 reading seemed not to be the key mechanism behind intra-orthographic effects. L2 graphemes were likely to be decoded with incorrect L2 grapheme-to-phoneme correspondences, resulting in intra-orthographic effects
Logarithmic perturbation theory for quasinormal modes
Logarithmic perturbation theory (LPT) is developed and applied to quasinormal
modes (QNMs) in open systems. QNMs often do not form a complete set, so LPT is
especially convenient because summation over a complete set of unperturbed
states is not required. Attention is paid to potentials with exponential tails,
and the example of a Poschl-Teller potential is briefly discussed. A numerical
method is developed that handles the exponentially large wavefunctions which
appear in dealing with QNMs.Comment: 24 pages, 4 Postscript figures, uses ioplppt.sty and epsfig.st
Quasinormal Modes of Dirty Black Holes
Quasinormal mode (QNM) gravitational radiation from black holes is expected
to be observed in a few years. A perturbative formula is derived for the shifts
in both the real and the imaginary part of the QNM frequencies away from those
of an idealized isolated black hole. The formulation provides a tool for
understanding how the astrophysical environment surrounding a black hole, e.g.,
a massive accretion disk, affects the QNM spectrum of gravitational waves. We
show, in a simple model, that the perturbed QNM spectrum can have interesting
features.Comment: 4 pages. Published in PR
Retinal Changes in a Mutant Form of Goldfish with Megalophthalmia
The retinal changes of a mutant strain of goldfish with megalophthalmia were studied by histology, electron microscopy and biochemistry. Changes in the morphology of the pigment epithelium, decrease in number of photoreceptors, thinning out of retinal layers and the existence of spaces in the retina were all features as the eyes grew in size. Invasion of macrophages was also evident in the retina. A decrease in leucine uptake per milligram of retina was also detected as the eye grew beyond 0.8 millilitre in volume. These changes, although related to volume changes (i.e., growth) of the eyes, were found to have little relationship with increase of intraocular pressure as intraocular pressures in the growing eyes of the mutant strain did not change much. Goldfish from a control strain with similar eye volumes and sizes (ages) were used for comparison and similar changes as in the mutant were not apparent
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