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Laser-based optical links offer the possibility of secure, high data rate underwater communication. Challenges include quickly modulating the light, and rapidly and reliably decoding the received s...

We report on experiments where non-uniformly correlated (NUC), Gaussian Schell (GSM) and Multi-Gaussian Schell (MGSM) model spatially partially coherent laser beams were propagated underwat...

Off-axis underwater scattering of spatially partially coherent Multi-Gaussian Schell-Model (MGSM) beams are compared with fully coherent Gaussian beams in both a stationary setting and in the presence of mechanically agitated scatterers in underwater environments. The analysis is carried out by comparing the mean intensities of scattered light, the normalized variance, and the scintillation index in various scenarios. Results indicate that fully coherent beams have increased off-axis scattered light variations in the presence of moving scatterers as compared with a spatially partially coherent MGSM beam. Additionally, in a stationary environment the coherent beam has less overall variations as expected due to the nature of constructing partially coherent MGSM beams. Metrics of normalized variance, scintillation index, and overall average intensity are discussed in the context of potential beam localization, reduced scattering, and off-axis detection.

The equation of “golden lads” and “chimney-sweepers”, alluded to in the dirge in Cymbeline, with, respectively, the flower-heads and clocks of the dandelion (Taraxacum officinale) is a twentieth-century myth, perhaps even a hoax. Neither phrase has been recorded, even in Warwickshire, as a vernacular name for the dandelion, a plant not mentioned anywhere in Shakespeare's works. The history of the myth, widely propagated by Hugh Kenner in his 1971 book The Pound Era and uncritically repeated by various authors since then, is traced.

It is experimentally demonstrated that the class of partially coherent, partially polarized optical beams can be efficiently used for reduction in scintillations on propagation through turbulent air. The experiment involving the electromagnetic beam generation and its interaction with turbulent air simulator is discussed in details. The collected data is in solid agreement with the recently published theoretical predictions.

Measurements of intensity statistics of a spatially pre-randomized laser beam propagating in a turbulent atmosphere along two horizontal links in close proximity to grassy ground and above a creek have been carried out in the fall of 2012. The pre-randomization of the laser beam was made by using a nematic Spatial Light Modulator placed at the laser source exit. The beam’s phase is randomized with Gaussian statistics with zero mean and fully controllable degree of coherence. The receiver consisted of an amplified photodetector and data acquisition device which were used to capture the beam intensity fluctuations after propagation through turbulent media. The results for the intensity Probability Density Function (PDF), the Cumulative Distribution Function and, in particular, for the scintillation index are presented for a variety of the source’s states of coherence and environmental conditions. The analytical PDF is reconstructed from the statistical moments of intensity with the help of the Gamma-Laguerr...

New social-sharing applications are transforming the Internet from a read-only (Web 1.0) environment to a read-write ecology that many are calling Web 2.0. These tools (e.g., weblogs and wikis) enable Internet users to publish information online almost as easily as they can read online, and they have tremendous potential for learning. This article provides illustrative comparisons of Web 1.0 and Web 2.0 tools to illuminate three key characteristics of the Web 2.0 platform: (a) user-initiated publishing of information without significant technical knowledge, (b) social networking, and (c) online communities formed around specific content. Key concepts, terms, and technologies central to Web 2.0, including Education 2.0, Web 2.0 students, Web 2.0 platforms and tools, and collective wisdom, are considered, along with implications for education and future research.

William Robinson (1838–1935) was one of the most significant horticulturists of the late nineteenth and early twentieth centuries, publishing, among other titles, The Wild Garden (1870) and The English Flower Garden (1883), and founding a series of periodicals including The Garden, Gardening Illustrated and Flora and Sylva. Robinson was Irish by birth, but spent almost his entire adult life, after 1860, in England.

Testing of fluted boomerangs and throwing sticks has shown that the Australian Aborigine preceded Western civilisation by thousands of years in the application of some aerodynamic technologies. At first glance it may seem that the longitudinal flutes on the distinctive throwing sticks and hunting boomerangs of Central and Western Australia must diminish their aerodynamic performance. Nothing could be further from the truth. These surface features enhance the performance. Wind tunnel tests show large drag force reductions in the case of throwing sticks and large lift force increases in the case of boomerangs. The fluting alone is responsible for the improved performance. In fact it can be shown that, without the fluting, some boomerangs may not have flown at all.

In 1803 Robert Scott published an illustrated paper describing two mosses, Grimmia maritima and Dicranum scottianum which he had gathered in Ireland. His paper predates Dawson Turner's Muscologiae Hibernicae spicilegium published in 1804, in which the two species were also described. Thus Scott, and not Turner, was the author of these binomials, and the authorities for the species therefore need to be adjusted thus, Grimmia maritima Sm. ex R. Scott (= Schistidium maritimum (Sm. ex R. Scott) Bruch & Schimp.) and Dicranum scottianum Turner ex R. Scott. Type specimens are discussed, in particular isolectotypes are reported in the herbarium of the National Botanic Gardens, Glasnevin, Dublin (DBN).

Summary Botanical exploration in Ireland before 1800 was conducted mainly by individuals, e.g. Richard Heaton (c. 1640), William Sherard(c. 1692), CalebThrelkeld(c. 1726). There was one attempt in the mid-1700s by the Physico-Historical Society to organize a concerted programme of botanical investigation. This paper concentrates on three separate recorders of the Irish flora and their extant manuscripts, Don Philip O'Sullivan Beare (c. 1625), John Rutty (c. 1740) and Patrick Browne (c. 1780). A manuscript account of the Irish flora survives from the first quarter of the seventeenth century. Philip O'Sullivan Beare wrote Zoiloinastix about 1623, as a response to the disparaging writings of such authors as Giraldus Cambrensis. O'Sullivan Beare clearly had first-hand knowledge of some gardens and forests, and seems to have been well-versed in botany. The Physico-Historical Society of Ireland promoted natural history exploration. Dr John Rutty was the person who apparently co-ordinated the programme. Isaac Bu...

(1992). Synthesis of the Four PATCH Evaluations. Journal of Health Education: Vol. 23, PATCH: Community Health Promotion, pp. 187-192.

Summary Specimens (ex herb. William McNab) collected by Dr Patrick Neill (1776–1851), of Canonmills, Edinburgh, in his own garden and other Scottish gardens (including the Botanic Garden, Edinburgh), c. 1799–1805, are noted and catalogued. Some represent horticultural hybrids of local origin, and a few specimens originated from seeds captured from French naturalists during the Napoleonic Wars.

The basionym of Lophomyrtus bullata (Sol. ex A. Cunn.) Burret being illegitimate, a new binomial, L. aotearoana E. C. Nelson, is provided for the endemic New Zealand myrtle.

(1937). A Study of the Extent of Agreement between Friends' Opinions and their Ability to Estimate the Opinions of Each Other. The Journal of Social Psychology: Vol. 8, No. 4, pp. 433-442.

* Accepted for publication by C. J. Warden of the Editorial Board, and received in the Editorial Office on July 22, 1937.

(1941). The Comparative Approach to Typology. The Journal of General Psychology: Vol. 24, No. 1, pp. 39-48.

* Received in the Editorial Office on July 22, 1937. 1 This investigation was carried out in the Laboratories of the Department of Neuropathology of the Psychiatric Institute of the State of New York, to the directors of which the authors wish to acknowledge their appreciation for the use of the facilities.

The publication of the name Olearia semidentata by Decaisne in 1846 is discussed, and confusing statements about its holotype are clarified. The holotype collected by Pfihl on the Chatham Islands in November 1838 is in Paris.