The continuous plankton recorder survey: A long-term, basin-scale oceanic time series

In the 1920s, before the advent of echo sounders, fishery biologists were greatly concerned with assisting the fisherman to locate schools of pelagic fish. One of the approaches they developed was to relate the distribution of the planktonic food organisms to the presence of the schools of predators such as herring (Clupea harengus). The British planktologist, Alister Hardy, who had already carried out extensive studies on the feeding preferences of herring (Hardy, 1926a), initiated a program to examine the fishermen's contention that herring schools avoided 'green', i.e., phytoplankton-rich, water but could be correlated with high concentrations of zooplankton. This practical program was centered on the use of a specially developed instrument, the 'Plankton Indicator', designed to be used by the fisherman to assist in the search for suitable waters. It had limited success in its main aim but, as a collecting device, it embodied several profoundly important features. It was a simple instrument which was robust enough to be deployed and recovered by the crew of commercial vessels (in this case fishing vessels) while they were underway. The Indicator however, was no more than a high speed net which integrated the plankton over the area of sampling, but Hardy had also become interested in describing the patchiness of planktonic populations. He thus developed the Continuous Plankton Recorder (CPR) where he substituted the fixed filter screen of the Indicator by a continually moving length of silk mesh. The screen traversed at constant speed across the path of the incoming water and the trapped organisms were retained in place by sandwiching beneath an additional second mesh screen. Thus, knowing the speed of the towing vessel and the shooting and hauling positions, the spatial patterns of the plankton could be determined. Hardy took the first CPR to the Antarctic where he used it in the Southern Atlantic (Hardy, 1926b) and later deployed it in the North Sea to make some of the earliest contiguous records of plankton patchiness

Asymptotic Multi-Layer Analysis of Wind Over Unsteady Monochromatic Surface Waves

Asymptotic multi-layer analyses and computation of solutions for turbulent flows over steady and unsteady monochromatic surface wave are reviewed, in the limits of low turbulent stresses and small wave amplitude. The structure of the flow is defined in terms of asymptotically-matched thin-layers, namely the surface layer and a critical layer, whether it is elevated or immersed, corresponding to its location above or within the surface layer. The results particularly demonstrate the physical importance of the singular flow features and physical implications of the elevated critical layer in the limit of the unsteadiness tending to zero. These agree with the variational mathematical solution of Miles (1957) for small but finite growth rate, but they are not consistent physically or mathematically with his analysis in the limit of growth rate tending to zero. As this and other studies conclude, in the limit of zero growth rate the effect of the elevated critical layer is eliminated by finite turbulent diffusivity, so that the perturbed flow and the drag force are determined by the asymmetric or sheltering flow in the surface shear layer and its matched interaction with the upper region. But for groups of waves, in which the individual waves grow and decay, there is a net contribution of the elevated critical layer to the wave growth. Critical layers, whether elevated or immersed, affect this asymmetric sheltering mechanism, but in quite a different way to their effect on growing waves. These asymptotic multi-layer methods lead to physical insight and suggest approximate methods for analyzing higher amplitude and more complex flows, such as flow over wave groups.Comment: 20 page

How accurately do adult sons and daughters report and perceive parental deaths from coronary disease?

<b>OBJECTIVES</b>: To describe how adult sons and daughters report and perceive parental deaths from heart disease <b>DESIGN</b>: Two generation family study. <b>SETTING</b>: West of Scotland. <b>SUBJECTS</b>: 1040 sons and 1298 daughters aged 30-59 from 1477 families, whose fathers and mothers were aged 45-64 in 1972-76 and have been followed up for mortality over 20 years. <b>OUTCOME</b> : Perception of a "family weakness" attributable to heart disease. RESULTS : 26% of sons and daughters had a parent who had died of coronary heart disease (CHD). The proportion was higher in older offspring (+18% per 10 year age difference) and in manual compared with non-manual groups (+37%). Eighty nine per cent of parental deaths from CHD were correctly reported by offspring. Only 23% of sons and 34% of daughters with at least one parent who had died of CHD considered that they had a family weakness attributable to heart disease. Perceptions of a family weakness were higher when one or both parents had died of CHD, when parental deaths occurred at a younger age, in daughters compared with sons and in offspring in non-manual compared with manual occupations. <b>CONCLUSIONS</b>: Only a minority of sons and daughters with experience of a parent having died from CHD perceive this in terms of a family weakness attributable to heart disease. Although men in manual occupations are most likely to develop CHD, they are least likely to interpret a parental death from CHD in terms of a family weakness. Health professionals giving advice to patients on their familial risks need to be aware of the difference between clinical definitions and lay perceptions of a family history of heart disease

Experimental measurement of focused wave group and solitary wave overtopping

Prediction of individual wave overtopping events is important in assessing danger to life and property, but data are sparse and hydrodynamic understanding is lacking. Laboratory-scale waves of three distinct types were generated at the Coastal Research Facility to model extreme waves overtopping a trapezoidal embankment. These comprised wave groups of compact form, wave groups embedded in a background wave field, and a solitary wave. The inshore wave propagation was measured and the time variation of overtopping rate estimated. The total volume overtopped was measured directly. The experiments provide well-defined data without uncertainty due to the effect of reflection on the incident wave train. The dependence of overtopping on a range of wave shapes is thus determined and the influence of wave-wave interactions on overtopping assessed. It was found that extreme overtopping may arise from focused waves with deep troughs rather than large crests. Furthermore, overtopping waves can be generated from small wave packets without affecting the applicability of results to cases in which there are surrounding waves. Finally, overtopping from a solitary wave is comparable with overtopping from focused wave groups of the same amplitude. © 2011 Copyright International Association for Hydro-Environment Engineering and Research

Near-infrared observations of galaxies in Pisces-Perseus: I. H-band surface photometry of 174 spirals

We present near-infrared, H-band (1.65 um), surface photometry of 174 spiral galaxies in the area of the Pisces-Perseus supercluster. The images, acquired with the ARNICA camera mounted on various telescopes, are used to derive radial profiles of surface brightness, ellipticities, and position angles, together with global parameters such as H-band magnitudes and diameters. The mean relation between H-band isophotal diameter D_{21.5} and the B-band D_{25} implies a B-H color of the outer disk bluer than 3.5; moreover, D_{21.5}/D_{25} depends on (global) color and absolute luminosity. The correlations among the various photometric parameters suggest a ratio between isophotal radius D_{21.5}/2 and disk scale length of about 3.5 and a mean disk central brightness of 17.5 H-mag arcsec^{-2}. We confirm the trend of the concentration index C_{31} with absolute luminosity and, to a lesser degree, with morphological type. We also assess the influence of non-axisymmetric structures on the radial profiles and on the derived parameters.Comment: 10 pages, 11 postscript figures (one table and one figure are available only at the CDS); to be published on A&A

Entrainment by turbulent fountains

This is the author accepted manuscript. The final version is available from Cambridge University Press via https://doi.org/10.1017/jfm.2016.16Experimental measurements of entrainment by turbulent fountains from circular sources in quiescent uniform environments are presented. Our results span almost four orders of magnitude in the source Froude number (0.004 ≤ Fr₀ ≤ 25) and thereby encompass the entrainment across all classes of fountain behaviour identified to date. We identify scalings for the entrained volume flux Qᴇ, in terms of Fr₀ and the source volume flux Q₀, within a number of distinct Froude-number bands corresponding to each class of fountain. Additionally we identify a distinct class of new behaviour, as yet unreported, for Fr₀ ≲ 0.1

Multilayered folding with voids

In the deformation of layered materials such as geological strata, or stacks of paper, mechanical properties compete with the geometry of layering. Smooth, rounded corners lead to voids between the layers, while close packing of the layers results in geometrically-induced curvature singularities. When voids are penalized by external pressure, the system is forced to trade off these competing effects, leading to sometimes striking periodic patterns. In this paper we construct a simple model of geometrically nonlinear multi-layered structures under axial loading and pressure confinement, with non-interpenetration conditions separating the layers. Energy minimizers are characterized as solutions of a set of fourth-order nonlinear differential equations with contact-force Lagrange multipliers, or equivalently of a fourth-order free-boundary problem. We numerically investigate the solutions of this free boundary problem, and compare them with the periodic solutions observed experimentally

Growth and Wood Properties of Rapid-Grown Japanese Larch

Japanese larch grown under intensive management practices (i.e. fertilization, irrigation, and cultivation) exhibited rapid juvenile growth; diameter and height averaged 15.7 cm and 9.2 m, respectively, in 10 yr. Whole-ring specific gravity decreased for several years after fertilization and then increased; it was influenced by the presence of large amounts of transition wood and low latewood percent. X-ray analysis also showed that specific gravity was quite uniform within the annual rings after fertilization. The percentage of extractives was low throughout the trees; this may have been related to the absence of heartwood formation. The pattern of both latewood percent and percent of extractives indicated that the juvenile wood zone in these trees was 10 yr. Furthermore, compression wood was present in most annual rings although it was primarily associated with the latewood. The possibilities of selecting for growth and wood properties in a tree improvement program for Japanese larch are discussed

System for the measurement of ultra-low stray light levels

An apparatus is described for measuring the effectiveness of stray light suppression light shields and baffle arrangements used in optical space experiments and large space telescopes. The light shield and baffle arrangement and a telescope model are contained in a vacuum chamber. A source of short, high-powered light energy illuminates portions of the light shield and baffle arrangement and reflects a portion of same to a photomultiplier tube by virtue of multipath scattering. The resulting signal is transferred to time-channel electronics timed by the firing of the high energy light source allowing time discrimination of the signal thereby enabling the light scattered and suppressed by the model to be distinguished from the walls and holders around the apparatus