Role of Gulf Stream Frontal Eddies in Forming Phytoplankton Patches on the Outer Southeastern Shelf

Continuous surface mapping of temperature, salinity, and chlorophyll along a 300-km segment of the Gulf Stream cyclonic front defined the spatial scales of a large diatom patch that persisted throughout a 10-day study. The patch was localized in the upwelled cold core of a Gulf Stream frontal eddy centered over the 200-m isobaths off Jacksonville, Florida, in April 1979. The µ g liter-1 surface chlorophyll isopleth enclosed an area \u3e1,000km2 with an alongshore dimension of 130km. Surface chlorophyll exceeded 5µg liter-1 within the upwelled cold core of the eddy, 10-100X higher than concentrations in Gulf Stream or resident shelf surface water. Diatoms dominated the patch with the maximum observed abundance \u3e106 cells liter-1. Several days after the initial shipboard mapping, the size, location, and strong chlorophyll gradients of the patch were confirmed with a surface chlorophyll image generated from an ocean color scanner (OCS) flown aboard a NASA U-2 aircraft. We show that the upwelling associated with eddies forming along the Gulf Stream cyclonic front results in localized zones of high near-surface production and plant biomass that lie adjacent to oligotrophic surface waters of the Gulf Stream

Ocean Chlorophyll Studies From a U-2 Aircraft Platform

Chlorophyll gradient maps of large ocean areas were generated from U-2/OCS data obtained over test sites in the Pacific and the Atlantic Oceans. The delineation of oceanic features using the upward radiant intensity relies on an analysis method which presupposes that radiation backscattered from the atmosphere and the ocean surface can be properly modeled by using a measurement made at 778 nm. The calculation of atmospheric radiance was performed by using a method developed by J.V. Dave. An estimation of the chlorophyll concentration is performed by properly ratioing radiances measured at 472 and 548 nm after removing the atmospheric effects. The correlation between the remotely sensed data and the in situ surface chlorophyll measurements has been validated in two sets of data. The results show that the correlation between the in situ measured chlorophyll and the derived quantity is a negative exponential function, and the correlation coefficient was calculated to be -0.965

Exploration of associations between the FTO rs9939609 genotype, fasting and postprandial appetite-related hormones and perceived appetite in healthy men and women

Background: The fat mass and obesity-associated gene (FTO) rs9939609 A-allele has been associated with obesity risk. Although the exact mechanisms involved remain unknown, the FTO rs9939609 A-allele has been associated with an impaired postprandial suppression of appetite. Objectives: To explore the influence of FTO rs9939609 genotype on fasting and postprandial appetite-related hormones and perceived appetite in a heterogeneous sample of men and women. Design: 112 healthy men and women aged 18-50-years-old completed three laboratory visits for the assessment of FTO rs9939609 genotype, body composition, aerobic fitness, resting metabolic rate, visceral adipose tissue, liver fat, fasting leptin, and fasting and postprandial acylated ghrelin, total PYY, insulin, glucose and perceived appetite. Participants wore accelerometers for seven consecutive days for the assessment of physical activity and sedentary behaviour. Multivariable general linear models quantified differences between FTO rs9939609 groups for fasting and postprandial appetite outcomes, with and without the addition of a priori selected physiological and behavioural covariates. Sex-specific univariable Pearson's correlation coefficients were quantified between the appetite-related outcomes and individual characteristics. Results: 95% confidence intervals for mean differences between FTO rs9939609 groups overlapped zero in unadjusted and adjusted general linear models for all fasting (P ≥ 0.28) and postprandial (P ≥ 0.19) appetite-related outcomes. Eta2 values for explained variance attributable to FTO rs9939609 were <5% for all outcomes. An exploratory correlation matrix indicated that associations between fasting and postprandial acylated ghrelin, total PYY and general or abdominal adiposity were also small (r = −0.23 to 0.15, P ≥ 0.09). Fasting leptin, glucose and insulin and postprandial insulin concentrations were associated with adiposity outcomes (r = 0.29 to 0.81, P ≤ 0.033). Conclusions: Associations between the FTO rs9939609 genotype and fasting or postprandial appetite-related outcomes were weak in healthy men and women

Variability of Surface Pigment Concentrations in the South Atlantic Bight

A 1‐year time sequence (November 1978 through October 1979) of surface pigment images from the South Atlantic Bight (SAB) was derived from the Nimbus 7 coastal zone color scanner. This data set is augmented with in situ observations of hydrographic parameters, freshwater discharge, sea level, coastal winds, and currents for the purpose of examining the coupling between physical processes and the spatial and temporal variability of the surface pigment fields. The SAB is divided into three regions: the east Florida shelf, the Georgia‐South Carolina shelf and the Carolina Capes. Six‐month seasonal mean pigment fields and time series of mean values within subregions were generated. While the seasonal mean isopleths were closely oriented along isobaths, significant differences between seasons in each region were found to exist. These differences are explained by correlating the pigment time series with physical parameters and processes known to be important in the SAB. Specifically, summertime concentrations between Cape Romain and Cape Canaveral were greater than those in winter, but the opposite was true north of Cape Romain. It is suggested that during the abnormally high freshwater discharge in the winter‐spring of 1979, Cape Romain and Cape Fear were the major sites of cross‐shelf transport, while the cross‐shelf exchange during the fall of 1979 occurred just north of Cape Canaveral. Finally, the alongshore band of high pigment concentrations increased in width throughout the year in the vicinity of Charleston, but near Jacksonville it exhibited a minimum width in the summer and a maximum width in the fall of 1979

Korištenje povlačne podvodne kamere za procjene škampa, hlapića i morskog pera u Jadranskom moru

Norway lobster, Nephrops norvegicus, is of great commercial importance throughout the NE Atlantic and Mediterranean, where it lives in burrows within muddy sediments. In several European countries it is assessed by means of towed underwater TV techniques. These are particularly suited to N. norvegicus because, for a number of reasons, the application of common fishery-dependent stock-assessment methods is not thorough for this species. The TV-based methodology relies on the fact that a known surface area of seabed is visually assessed and the number of N. norvegicus burrows, whose features are distinct, can be counted and their inhabitants quantified. It follows that, in theory, the same can be done for other organisms or key ecological features which appear on the footage. This study reports the results of the underwater television surveys (2009 and 2010) carried out jointly by Italy and Croatia in the Pomo/Jabuka pits, an area of the Adriatic Sea important for its N. norvegicus fishery and its hake nursery grounds. The obtained footage allowed quantification of the density of N. norvegicus in the area and the acquisition of estimates of the abundances of the squat lobster, Munida rutllanti and the sea pen Funiculina quadrangularis. The concurrent quantification of trawling activity from the footage has allowed us to place our results in the context of an ecosystem approach to fisheries management.Škamp ( Nephrops norvegicus ) je izuzetno važna gospodarska vrsta koja obitava u rupama u muljevitom sedimentu diljem sjeverno-istočnog Atlantika i Mediterana. Obzirom da uobičajene metode procjene bioloških resursa koje se zasnivaju na ribolovu nisu u potpunosti pogodne za ovu vrstu, nekoliko Europskih zemalja procjene populacije škampa obavlja korištenjem povlačne podvodne kamere. Ova metodologija bazira se na činjenici da škamp u sedimentu iskapa rupe karakterističnog izgleda koje se determiniraju i prebrojavaju vizualnim pregledom snimke dobivene povlačenjem podvodne kamere preko određene površine morskog dna. Teoretski, ova metodologija se može primijeniti i za procjene drugih vrsta ili ekoloških parametara koji su zabilježeni na snimkama. Ova studija iznosi rezultate istraživanja podvodnom kamerom (2009. i 2010. godine) koje su zajednički proveli Italija i Hrvatska na području Jabučke kotline u Jadranskom moru. Ovo područje koje se intenzivno gospodarski iskorištava značajno je kao glavno mrijestilište i rastilište većeg broja pridnenih vrsta, posebno škampa i oslića ( Merluccius merluccius ) Na osnovu dobivenih snimki izrađena je procjena brojnosti i biomase škampa, kao i procjena brojnosti hlapića ( Munida rutllanti ) i morskog pera ( Funiculina quadrangularis ). Istodobna procjena tragova koćarenja zabilježenih na snimkama omogućila nam je da ove rezultate stavimo u kontekst ekosustavnog pristupa gospodarenju bioloških resursa mora

Angular position of nodes in the superconducting gap of YBCO

The thermal conductivity of a YBCO single crystal has been studied as a function of the relative orientation of the crystal axes and a magnetic field rotating in the Cu-O planes. Measurements were carried out at several temperatures below T_c and at a fixed field of 30 kOe. A four-fold symmetry characteristic of a superconducting gap with nodes at odd multiples of 45 degrees in k-space was resolved. Experiments were performed to exclude a possible macroscopic origin for such a four-fold symmetry such as sample shape or anisotropic pinning. Our results impose an upper limit of 10% on the weight of the s-wave component of the essentially d-wave superconducting order parameter of YBCO.Comment: 10 pages, 4 figure

Aerosol optical hygroscopicity measurements during the 2010 CARES campaign

Measurements of the effect of water uptake on particulate light extinction or scattering made at two locations during the 2010 Carbonaceous Aerosols and Radiative Effects Study (CARES) study around Sacramento, CA are reported. The observed influence of water uptake, characterized through the dimensionless optical hygroscopicity parameter γ, is compared with calculations constrained by observed particle size distributions and size-dependent particle composition. A closure assessment has been carried out that allowed for determination of the average hygroscopic growth factors (GFs) at 85% relative humidity and the dimensionless hygroscopicity parameter κ for oxygenated organic aerosol (OA) and for supermicron particles (defined here as particles with aerodynamic diameters between 1 and 2.5 microns), yielding κ = 0.1–0.15 and 0.9–1.0, respectively. The derived range of oxygenated OA κ values are in line with previous observations. The relatively large values for supermicron particles is consistent with substantial contributions of sea-salt-containing particles in this size range. Analysis of time-dependent variations in the supermicron particle hygroscopicity suggest that atmospheric processing, specifically chloride displacement by nitrate and the accumulation of secondary organics on supermicron particles, can lead to substantial depression of the observed GF

Ethical and methodological issues in engaging young people living in poverty with participatory research methods

This paper discusses the methodological and ethical issues arising from a project that focused on conducting a qualitative study using participatory techniques with children and young people living in disadvantage. The main aim of the study was to explore the impact of poverty on children and young people's access to public and private services. The paper is based on the author's perspective of the first stage of the fieldwork from the project. It discusses the ethical implications of involving children and young people in the research process, in particular issues relating to access and recruitment, the role of young people's advisory groups, use of visual data and collection of data in young people's homes. The paper also identifies some strategies for addressing the difficulties encountered in relation to each of these aspects and it considers the benefits of adopting participatory methods when conducting research with children and young people

A semiconductor source of triggered entangled photon pairs?

The realisation of a triggered entangled photon source will be of great importance in quantum information, including for quantum key distribution and quantum computation. We show here that: 1) the source reported in ``A semiconductor source of triggered entangled photon pairs''[1. Stevenson et al., Nature 439, 179 (2006)]} is not entangled; 2) the entanglement indicators used in Ref. 1 are inappropriate, relying on assumptions invalidated by their own data; and 3) even after simulating subtraction of the significant quantity of background noise, their source has insignificant entanglement.Comment: 5 pages in pre-print format, 1 tabl