A one-dimensional model of meridional oceanic heat transport

A one-dimensional model for the global meridional oceanic heat transport flux distribution is established which indicates the dominant role of the Ekman heat transports between 35N and 30S, in which the depth averaged ocean temperature is approximately constant, and of the Ekman and diffusive transports at higher latitudes where the depth-average temperature decreases...

Eddy friction in the ocean

The scalar energy spectrum of steady isotropic two-dimensional turbulence is derived for two-dimensional motion in a homogeneous ocean in which the dissipation occurs in a bottom-friction layer. The significant property of the spectrum is a range of wave numbers in which the mean-squared vorticity is conserved and energy is transferred to the friction layer...

The wave-drift current

The irrotational wave-drift current associated with the one-dimensional eq uilibrium wave spectrum is calculated, and by comparison with observation, it is shown that in many situations this current may make an important contribution to surface-drift velocities. One of the interesting features of the irrotational current profile is a remarkable affinity to the logarithmic profile of similarity theory, both formally and quantitatively

The coupling of wave drift and wind velocity profiles

The Stokes drift velocity profile due to Toba\u27s equilibrium wave spectrum is shown to consist of a surface constant shear layer, an intermediate logarithmic layer and a deep exponentially decaying tail. On identifying the logarithmic layer with a wall boundary layer (which is justified a posteriori by showing that the major part of the energy dissipation by wave breaking occurs in the roughness sublayer), for a range of directionality (p) of the wave spectrum ½–2, Toba\u27s constant (α) lies in the range 0.12–0.10 in good agreement with data. The roughness length for water (z0) of this profile has the Charnock form, z0 = au2*g–1 in which u* is the friction velocity in air, g is the acceleration of gravity and a is a constant of order unity determined by the condition that momentum transfer by wave breaking just supports the wind stress, and using this formula the transition from smooth to intermediate flow at which rippling commences is quite well estimated. The velocity profiles in air and water with respect to z0, are predicted from a similarity hypothesis to have the formsu′ = u* (γ + 1/κ ln z/z0) u = w* (γ − 1/κ ln z/z0) z \u3e z0where z is the distance from the sea surface, u′ and u are respectively the velocities in air and water, κ is Von Karman\u27s constant, w* is the friction velocity in water, γw* is the Stokes surface drift velocity, and γu* is a wave speed centered in the equilibrium range. Observations in the open sea indicate that γ ∼ 12. An alternate pair of profiles, also predicted from the similarity hypothesis, is,u′ = us + u*/κ ln z/z′0 u = us − w*/κ ln z/z′0 z \u3e z′0where z′0 is the roughness length for air, and us ∼ 2γw* is the surface current. Observations suggest that small surface drifters travel at speeds intermediate between γw* and 2γw

Foraminiferal evidence for the intensification of the east Australia current during the LGM

Abstrac

Determination of suitable housekeeping genes for normalisation of quantitative real time PCR analysis of cells infected with human immunodeficiency virus and herpes viruses

The choice of an appropriate housekeeping gene for normalisation purposes has now become an essential requirement when designing QPCR experiments. This is of particular importance when using QPCR to measure viral and cellular gene transcription levels in the context of viral infections as viruses can significantly interfere with host cell pathways, the components of which traditional housekeeping genes often encode. In this study we have determined the reliability of 10 housekeeping genes in context of four heavily studied viral infections; human immunodeficiency virus type 1, herpes simplex virus type 1, cytomegalovirus and varicella zoster virus infections using a variety of cell types and virus strains. This provides researchers of these viruses with a shortlist of potential housekeeping genes to use as normalisers for QPCR experiments

A functional description of CymA, an electron-transfer hub supporting anaerobic respiratory flexibility in Shewanella

CymA (tetrahaem cytochrome c) is a member of the NapC/NirT family of quinol dehydrogenases. Essential for the anaerobic respiratory flexibility of shewanellae, CymA transfers electrons from menaquinol to various dedicated systems for the reduction of terminal electron acceptors including fumarate and insoluble minerals of Fe(III). Spectroscopic characterization of CymA from Shewanella oneidensis strain MR-1 identifies three low-spin His/His co-ordinated c-haems and a single high-spin c-haem with His/H2O co-ordination lying adjacent to the quinol-binding site. At pH 7, binding of the menaquinol analogue, 2-heptyl-4-hydroxyquinoline-N-oxide, does not alter the mid-point potentials of the high-spin (approximately −240 mV) and low-spin (approximately −110, −190 and −265 mV) haems that appear biased to transfer electrons from the high- to low-spin centres following quinol oxidation. CymA is reduced with menadiol (Em=−80 mV) in the presence of NADH (Em=−320 mV) and an NADH–menadione (2-methyl-1,4-naphthoquinone) oxidoreductase, but not by menadiol alone. In cytoplasmic membranes reduction of CymA may then require the thermodynamic driving force from NADH, formate or H2 oxidation as the redox poise of the menaquinol pool in isolation is insufficient. Spectroscopic studies suggest that CymA requires a non-haem co-factor for quinol oxidation and that the reduced enzyme forms a 1:1 complex with its redox partner Fcc3 (flavocytochrome c3 fumarate reductase). The implications for CymA supporting the respiratory flexibility of shewanellae are discussed.</jats:p

Effectiveness of Subgingival Scaling and Root Planing: Single Versus Multiple Episodes of Instrumentation

Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/142277/1/jper0367.pd

Enhanced Thermal Stability and Reduced Aggregation in an Antibody Fab Fragment at Elevated Concentrations

The aggregation of protein therapeutics such as antibodies remains a major challenge in the biopharmaceutical industry. The present study aimed to characterize the impact of the protein concentration on the mechanisms and potential pathways for aggregation, using the antibody Fab fragment A33 as the model protein. Aggregation kinetics were determined for 0.05 to 100 mg/mL Fab A33, at 65 °C. A surprising trend was observed whereby increasing the concentration decreased the relative aggregation rate, ln(v) (% day-1), from 8.5 at 0.05 mg/mL to 4.4 at 100 mg/mL. The absolute aggregation rate (mol L-1 h-1) increased with the concentration following a rate order of approximately 1 up to a concentration of 25 mg/mL. Above this concentration, there was a transition to an apparently negative rate order of -1.1 up to 100 mg/mL. Several potential mechanisms were examined as possible explanations. A greater apparent conformational stability at 100 mg/mL was observed from an increase in the thermal transition midpoint (Tm) by 7-9 °C, relative to those at 1-4 mg/mL. The associated change in unfolding entropy (△Svh) also increased by 14-18% at 25-100 mg/mL, relative to those at 1-4 mg/mL, indicating reduced conformational flexibility in the native ensemble. Addition of Tween or the crowding agents Ficoll and dextran, showed that neither surface adsorption, diffusion limitations nor simple volume crowding affected the aggregation rate. Fitting of kinetic data to a wide range of mechanistic models implied a reversible two-state conformational switch mechanism from aggregation-prone monomers (N*) into non-aggregating native forms (N) at higher concentrations. kD measurements from DLS data also suggested a weak self-attraction while remaining colloidally stable, consistent with macromolecular self-crowding within weakly associated reversible oligomers. Such a model is also consistent with compaction of the native ensemble observed through changes in Tm and △Svh

Unpacking physically active learning in education: a movement didaktikk approach in teaching?

This paper explores teachers’ educational values and how they shape their judgements about physically active learning (PAL). Twenty one teachers from four primary schools in Norway participated in focus groups. By conceptualising PAL as a didaktikk approach, the findings indicated that teachers engaged with PAL in a way that reflected their professional identity and previous experiences with the curriculum. Teachers valued PAL as a way of getting to know pupils in educational situations that were different from those when sedentary. These insights illustrate how PAL, as a didaktikk approach to teaching, can shift teachers’ perceptions of pupils’ knowledge, learning, and identity formation in ways that reflect the wider purposes of education. The paper gives support to a classroom discourse that moves beyond the traditional, sedentary one-way transfer of knowledge towards a more collaborative effort for pupils’ development.publishedVersio