1,024 research outputs found
Effect of broodstock holding environment on egg quality in farmed brown trout (Salmo trutta)
Brown trout (Salmo trutta) broodstock from a
single population were separated prior to spawning and
exposed to two different holding environments: a
‘raceway system’ and a ‘tank system’. Eggs were
stripped from females and 13 measures of egg quality
were collected, analysed individually, combined by
principle components analysis into an integrated egg
quality score which was validated against egg survival.
The multivariate egg quality score (PC1) differed for
fish held in the tank and raceway systems. Egg survival,
chorion breaking strength and chorion Se concentrations
were higher in eggs produced by broodstock held in the
tank system compared to those in the raceway system.
In contrast, chorion concentrations of P and K were
higher in eggs from fish held in the raceway system.
The results suggest that brown trout broodstock reared
in tank systems produced higher quality eggs compared
to trout reared in raceways. Finally, this study also
indicates that multivariate statistical analysis can be
used to determine egg quality from multiple egg
parameters
Mixed media : feminist presses and publishing politics in twentieth-century Britain
The high cultural profile of contemporary feminist publishing in Britain has
previously met with a curiously evasive response from those spheres of academic
discourse in which it might be expected to figure: women's studies, while asserting the
innate politicality of all communication, has tended to overlook the subject of publishing
in favour of less materialist cultural modes; while publishing studies has conventionally
overlooked the significance of gender as a differential in analysing print media. Siting
itself at this largely unexplored academic juncture, the thesis analyses the complex
interaction of feminist politics and fiction publishing in twentieth-century Britain.
Chapter 1 -" 'Books With Bite': Virago Press and the Politics of Feminist
Conversion" - focuses on Britain's oldest extant women's publishing venture, Virago
Press, and analyses the organisational structures and innovative marketing strategies
which engineered the success of its reprint and original fiction lists. Chapter 2 looks back
to Elizabeth Corbet Yeats's early-twentieth-century Cuala Press, a prominent element in
the Irish literary revival and debates around women's relationship to nationalist agendas.
The experience of The Women's Press, Black Woman Talk and Sheba Feminist Publishers
constitutes the crux of Chapter 3 - " 'Books of Integrity': Dilemmas of Race and
Authenticity in Feminist Publishing" - which reads these presses as challenges to the
early-second-wave women's movement insistence on the primacy of sisterhood for
women's identity politics. Chapter 4 investigates feminist publishing's historical
involvement in Edwardian suffrage politics and the vexed role of men within feminist
publishing enterprises. Radical feminist and lesbian publishing is scrutinised in Chapter
5- "Collective Unconscious: The Demise of Radical Feminist Publishing" - which centres
upon Onlywomen Press, Sheba and Silver Moon Books, and explores the problematic
nature of the collective principle for women's media enterprises. The concluding chapter
- "This Book Could Change Your Life': Feminist Bestsellers and the Power of
Mainstream Publishing" - assesses the impact of feminism on mainstream post-war
publishing. It critiques the ways in which mainstream houses' commissioning, design
and marketing of canonical feminist texts have frequently militated against their
oppositional content.
Central to the analysis as a whole is the dynamic tension arising from the
conjunction of radical politics and the commercial market-place, a relationship in which
the contesting exigencies of political progressiveness and business solvency create an
energising - though volatile - dialectic
3D MHD Flux Emergence Experiments: Idealized models and coronal interactions
This paper reviews some of the many 3D numerical experiments of the emergence
of magnetic fields from the solar interior and the subsequent interaction with
the pre-existing coronal magnetic field. The models described here are
idealized, in the sense that the internal energy equation only involves the
adiabatic, Ohmic and viscous shock heating terms. However, provided the main
aim is to investigate the dynamical evolution, this is adequate. Many
interesting observational phenomena are explained by these models in a
self-consistent manner.Comment: Review article, accepted for publication in Solar Physic
Impact of long-range interactions on the disordered vortex lattice
The interaction between the vortex lines in a type-II superconductor is
mediated by currents. In the absence of transverse screening this interaction
is long-ranged, stiffening up the vortex lattice as expressed by the dispersive
elastic moduli. The effect of disorder is strongly reduced, resulting in a
mean-squared displacement correlator =
characterized by a mere logarithmic growth with distance. Finite screening cuts
the interaction on the scale of the London penetration depth \lambda and limits
the above behavior to distances R<\lambda. Using a functional renormalization
group (RG) approach, we derive the flow equation for the disorder correlation
function and calculate the disorder-averaged mean-squared relative displacement
\propto ln^{2\sigma} (R/a_0). The logarithmic growth (2\sigma=1) in
the perturbative regime at small distances [A.I. Larkin and Yu.N. Ovchinnikov,
J. Low Temp. Phys. 34, 409 (1979)] crosses over to a sub-logarithmic growth
with 2\sigma=0.348 at large distances.Comment: 9 pages, no figure
Influence of surface coating on the intracellular behaviour of gold nanoparticles : a fluorescence correlation spectroscopy study
In the biomedical applications of nanoparticles (NPs), the proper choice of surface chemistry is a crucial aspect in their design. The nature of the coating can heavily impact the interaction of NPs with biomolecules, affect the state of aggregation, and ultimately determine their biological fate. As such, protein corona formation and the aggregation behaviour of gold NPs (Au NPs) are studied here. Au NPs are prepared with four distinct surface functionalisations, namely mercaptosuccinic acid (MSA), N-4-thiobutyroil glucosamine, HS-PEG5000 and HS-alkyl-PEG600. Corona formation, aggregation, and the intracellular behaviour of the Au NPs are then investigated by means of Fluorescence Correlation Spectroscopy (FCS) in cell culture media and in live cells. To evaluate the state of aggregation and the formation of a protein corona, the Au NPs are incubated in cell media and the diffusion coefficient is determined via FCS. The in vitro behaviour is compared with the level of aggregation of the NPs in cells. Diffusion times of the NPs are estimated at different positions in the cell after a one hour incubation period. It is found that the majority of MSA and glucose-Au NPs are present inside the cell as slowly diffusing species with diffusion times (\u3c4D) greater than 6000 \u3bcs (hydrodynamic diameter >250 nm). PEGylated Au NPs adsorb a small amount of protein and manifest low agglomeration both in media and in living cells. In particular, the HS-alkyl-PEG600 coating shows an excellent correlation between lower protein adsorption, 4-fold lower compared to the MSA coated NPs, and limited intracellular aggregation. In the case of single HS-alkyl-PEG600 coated NPs, it is found that typical intracellular \u3c4D values range from 500 to 1500 \u3bcs, indicating that these particles display reduced aggregation in the intracellular environment
A global biophysical typology of mangroves and its relevance for ecosystem structure and deforestation
Mangrove forests provide many ecosystem services but are among the world's most threatened ecosystems. Mangroves vary substantially according to their geomorphic and sedimentary setting; while several conceptual frameworks describe these settings, their spatial distribution has not been quantified. Here, we present a new global mangrove biophysical typology and show that, based on their 2016 extent, 40.5% (54,972 km2) of mangrove systems were deltaic, 27.5% (37,411 km2) were estuarine and 21.0% (28,493 km2) were open coast, with lagoonal mangroves the least abundant (11.0%, 14,993 km2). Mangroves were also classified based on their sedimentary setting, with carbonate mangroves being less abundant than terrigenous, representing just 9.6% of global coverage. Our typology provides a basis for future research to incorporate geomorphic and sedimentary setting in analyses. We present two examples of such applications. Firstly, based on change in extent between 1996 and 2016, we show while all types exhibited considerable declines in area, losses of lagoonal mangroves (- 6.9%) were nearly twice that of other types. Secondly, we quantify differences in aboveground biomass between mangroves of different types, with it being significantly lower in lagoonal mangroves. Overall, our biophysical typology provides a baseline for assessing restoration potential and for quantifying mangrove ecosystem service provision
Lubricating Bacteria Model for Branching growth of Bacterial Colonies
Various bacterial strains (e.g. strains belonging to the genera Bacillus,
Paenibacillus, Serratia and Salmonella) exhibit colonial branching patterns
during growth on poor semi-solid substrates. These patterns reflect the
bacterial cooperative self-organization. Central part of the cooperation is the
collective formation of lubricant on top of the agar which enables the bacteria
to swim. Hence it provides the colony means to advance towards the food. One
method of modeling the colonial development is via coupled reaction-diffusion
equations which describe the time evolution of the bacterial density and the
concentrations of the relevant chemical fields. This idea has been pursued by a
number of groups. Here we present an additional model which specifically
includes an evolution equation for the lubricant excreted by the bacteria. We
show that when the diffusion of the fluid is governed by nonlinear diffusion
coefficient branching patterns evolves. We study the effect of the rates of
emission and decomposition of the lubricant fluid on the observed patterns. The
results are compared with experimental observations. We also include fields of
chemotactic agents and food chemotaxis and conclude that these features are
needed in order to explain the observations.Comment: 1 latex file, 16 jpeg files, submitted to Phys. Rev.
The impact of working memory load on task execution and online plan adjustment during multitasking in a virtual environment
Three experiments investigated the impact of working memory load on online plan adjustment during a test of multitasking in young, nonexpert, adult participants. Multitasking was assessed using the Edinburgh Virtual Errands Test (EVET). Participants were asked to memorize either good or poor plans for performing multiple errands and were assessed both on task completion and on the extent to which they modified their plans during EVET performance. EVET was performed twice, with and without a secondary task loading a component of working memory. In Experiment 1, articulatory suppression was used to load the phonological loop. In Experiment 2, oral random generation was used to load executive functions. In Experiment 3, spatial working memory was loaded with an auditory spatial localization task. EVET performance for both good- and poor-planning groups was disrupted by random generation and sound localization, but not by articulatory suppression. Additionally, people given a poor plan were able to overcome this initial disadvantage by modifying their plans online. It was concluded that, in addition to executive functions, multiple errands performance draws heavily on spatial, but not verbal, working memory resources but can be successfully completed on the basis of modifying plans online, despite a secondary task load
Circulating syndecan-1 is reduced in pregnancies with poor fetal growth and its secretion regulated by matrix metalloproteinases and the mitochondria
Fetal growth restriction is a leading cause of stillbirth that often remains undetected during pregnancy. Identifying novel biomarkers may improve detection of pregnancies at risk. This study aimed to assess syndecan-1 as a biomarker for small for gestational age (SGA) or fetal growth restricted (FGR) pregnancies and determine its molecular regulation. Circulating maternal syndecan-1 was measured in several cohorts; a large prospective cohort collected around 36 weeks' gestation (n = 1206), a case control study from the Manchester Antenatal Vascular service (285 women sampled at 24-34 weeks' gestation); two prospective cohorts collected on the day of delivery (36 + 3-41 + 3 weeks' gestation, n = 562 and n = 405 respectively) and a cohort who delivered for preterm FGR (< 34 weeks). Circulating syndecan-1 was consistently reduced in women destined to deliver growth restricted infants and those delivering for preterm disease. Syndecan-1 secretion was reduced by hypoxia, and its loss impaired proliferation. Matrix metalloproteinases and mitochondrial electron transport chain inhibitors significantly reduced syndecan-1 secretion, an effect that was rescued by coadministration of succinate, a mitochondrial electron transport chain activator. In conclusion, circulating syndecan-1 is reduced among cases of term and preterm growth restriction and has potential for inclusion in multi-marker algorithms to improve detection of poorly grown fetuses
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