Copepods collected by the nuclear submarine SEADRAGON on a cruise to and from the North Pole, with remarks on their geographic distribution

A brief, non-detailed description is given of an automatic, multiple net plankton sampler used on a submarine cruise between the North Atlantic and Pacific oceans by way of the North Pole. The copepods contained in 90 samples from the Arctic have been identified and their relative abundance determined. The most frequently and widely occurring of the 18 species were Metridia longa, Calanus hyperboreus and C. glacialis. Pseudocalanus minutus, found mostly in the Chukchi Sea region, was the most abundant. From their known geographic distribution, six species are recognized as cosmopolites and 12 as Arctic or cold water species. Of the latter group, one is endemic to the Arctic and five are not known from the Pacific

Novel Cascaded Ultra Bright Pulsed Source of Polarization Entangled Photons

A new ultra bright pulsed source of polarization entangled photons has been realized using type-II phase matching in spontaneous parametric down conversion process in two cascaded crystals. The optical axes of the crystals are aligned in such a way that the extraordinarily (ordinarily) polarized cone from one crystal overlaps with the ordinarily (extraordinarily) polarized cone from the second crystal. This spatial overlapping removes the association between the polarization and the output angle of the photons that exist in a single type-II down conversion process. Hence, entanglement of photons originating from any point on the output cones is possible if a suitable optical delay line is used. This delay line is particularly simple and easy to implement.Comment: 8 pages 8 figure

Effect of fertility control on a population's productivity

The effect of a sterilising agent upon the productivity of vertebrate pests, such as feral horses, feral dogs, wild rabbits or fruit-eating birds, depends upon the population's social structure and mating system. We investigated the theoretical effect on productivity of three forms of dominance, two effects of sterilisation on dominance, and four modes of transmission. Seventeen of the possible 24 combinations are feasible but lead to only four possible outcomes. Three of these result in lowered productivity. The fourth, where the breeding of a dominant female suppresses breeding in the sub-ordinate females of her group, leads to a perverse outcome. Productivity increases with sterilisation unless the proportion of females sterilised exceeds (n- 2)/(n- 1) where n (> 2) is the number of females in the group. A knowledge of social structure and mating system is therefore highly desirable before population control by suppressing female fertility is attempted or even contemplated

Influence of the Amazon River outflow on the ecology of the western tropical Atlantic II. Zooplankton abundance, copepod distribution, with remarks on the fauna of low-salinity area

Zooplankton samples and hydrographic data were collected on two cruises to the area of the equatorial Atlantic that is influenced by the Amazon River outflow: one cruise during the dry season, October and November 1964, the other during the wet season that followed, May and June 1965. In the area where the cruise tracks overlapped, the average displacement volume of total zooplankton was almost three times higher during the wet season than during the dry season...

Australasian asphaltite strandings revisited: Their origin and the effects of weathering and biodegradation on their biomarker and isotopic profiles

Reports of bitumen strandings on the coastlines of South Australia, Victoria, Tasmania and Western Australia date from the early 19th Century (Sprigg and Woolley, 1963; Currie et al., 1992; Volkman et al., 1992; McKirdy et al., 1994; Padley, 1995; Edwards et al., 1998 and references therein). The locations of these strandings along Australia’s southern margin (Fig. 1), and their greater frequency in southeastern South Australia, western Victoria and southern Tasmania, fuelled early petroleum exploration in the region on the assumption that they were sourced from local submarine seepages (Sprigg, 1986; Volkman et al., 1992; McKirdy et al., 1994). Accounts describe a variety of oily substances that can be assigned to three categories, each with a different origin: oils (crude and refined), waxy bitumens and asphaltites (McKirdy et al., 1986, 1994; Padley, 1995; Edwards et al., 1998)

Report B, general biological oceanographic data from the Persian Gulf and Gulf of Oman

Quantitative phytoplankton (31 samples) and zooplankton (23 samples) collections were made throughout the Persian Gulf and at several places in the Gulf of Oman in spring 1977. In addition, 34 neuston tows were made in these areas. Approximately 100 species of phytoplankton were identified. Their numerical abundance ranged from 200 to 42,000 cells per liter. Diatoms were the most diverse taxa while coccolithophores were generally the dominant species numerically. Zooplankton biomass ranged from .11 to 2.00 cc/m3 and .52 to 2.27 cc/m3 in the Persian Gulf and Gulf of Oman respectively. Significantly higher volumes were recorded from the Gulf of Oman. The numerical abundance of zooplankton varied from 79 to 5098/m3. Copepods comprised more than 50% of the zooplankton in over one-half of the collections from the Persian Gulf. Higher zooplankton volumes occurred in the Central Persian Gulf. There was no significant differences in the quantities of zooplankton between day and night. Fourteen species of pontellid copepods were identified in neuston samples from the Persian Gulf and Gulf of Oman, including 10 species that represent new records for the Persian Gulf. Information on tar balls are summarized in an Appendix to this report.Prepared with funds from the Iranian Department of the Environment

Reliability of the beamsplitter based Bell-state measurement

A linear 50/50 beamsplitter, together with a coincidence measurement, has been widely used in quantum optical experiments, such as teleportation, dense coding, etc., for interferometrically distinguishing, measuring, or projecting onto one of the four two-photon polarization Bell-states $|\psi^{(-)}>$. In this paper, we demonstrate that the coincidence measurement at the output of a beamsplitter cannot be used as an absolute identifier of the input state $|\psi^{(-)}>$ nor as an indication that the input photons have projected to the $|\psi^{(-)}>$ state.Comment: 4 pages, two-colum