Comparison of tide-gauge data and a saltmarsh-derived reconstruction of mean sea-level for the Mersey Estuary

Using saltmarsh sediment cores, Mills (2011) reconstructed the historic trend of mean sea-level in the Mersey over a period since 1975. The analysis is based on the foraminifera species identified at different levels within the sediment core; each species being associated with a tidal elevation (for example, mean high water neap) identified from present-day vertical distribution of saltmarsh foraminifera at the coring sites. While the reconstruction at Decoy Marsh matched the tide gauge record at Gladstone Dock, the reconstruction at Oglet Bay for the period 1993 and 2003 disagreed. During this period the reconstruction suggested an initial drop in mean tidal level (MTL) of 50 cm followed by a 50 cm rise back to the underlying trend after 2002. Because a local drop in sea-level (SL) is unlikely, and the foraminifera fossils used in the reconstruction are unlikely to have changed their tolerance to inundation, another factor must account for this sea-level anomaly. Here using the 3D hydrodynamic Proudman Oceanographic Laboratory Coastal Ocean modelling System (POLCOMS), the impact of the position of the main estuarine channel and historic sea-level elevations on the tidal dynamics are investigated relative to the conditions in 2008. Changes in the proportion of time that certain elevations at the saltmarsh coring sites are inundated could explain the deviation observed in the reconstruction. Such an effect is hypothesised to occur in response to local changes in the tidal dynamics, i.e. changes in tidal range or asymmetry in tidal elevation. It is found that in response to changes in channel configuration to test the scenario of a northern channel migrating up-estuary through Oglet Bay, a change in inundation characteristics caused by a change in the bank drying phase of the tidal cycle, may well have contributed to the anomalous reconstruction

Sodium dependent inositol transport in HL60 cells is not related to Na+/K+, ATPase activity

AbstractIn HL60 cells, inositol transport is sodium-dependent but functionally independent of Na+/K+ ATPase activity. This observation has implications for the currently proposed theory for the development of diabetic complications

Structure of the Coulomb and unitarity corrections to the cross section of e+e−e^+e^- pair production in ultra-relativistic nuclear collisions

We analyze the structure of the Coulomb and unitarity corrections to the single pair production as well as the cross section for the multiple pair production. In the external field approximation we consider the probability of $e^+e^-$ pair production at fixed impact parameter $\rho$ between colliding ultra-relativistic heavy nuclei. We obtain the analytical result for this probability at large $\rho$ as compared to the electron Compton wavelength. We estimate also the unitary corrections to the total cross section of the process.Comment: 10 pages, 2 figures, RevTeX, references correcte

Quantum effects of a massive 3-form coupled to a Dirac field

We consider the coupling of A_{\mu\nu\rho} to the generic current of matter field, later identified with the spin density current of a Dirac field. In fact, one of the objectives of this paper is to investigate the impact of the quantum fluctuations of A_{\mu\nu\rho} on the effective dynamics of the spinor field. The consistency of the field equations, even at the classical level, requires the introduction of a mass term for A_{\mu\nu\rho}. In this case, the Casimir vacuum pressure includes a contribution that is explicitly dependent on the mass of A_{\mu\nu\rho} and leads us to conclude that the mass term plays the same role as the infrared cutoff needed to regularize the finite volume partition functional previously calculated in the massless case. Remarkably, even in the presence of a mass term, A_{\mu\nu\rho} contains a mixture of massless and massive spin-0 fields so that the resulting equation is still gauge invariant. This is yet another peculiar, but physically relevant property of A_{\mu\nu\rho} since it is reflected in the effective dynamics of the spinor fields and confirms the confining property of A_{\mu\nu\rho} already expected from the earlier calculation of the Wilson loop.Comment: 10 pages, Revtex, no figures; in print on Phys.Rev.D; added new reference

Pathophysiological changes in inner hair cell ribbon synapses in the ageing mammalian cochlea

Mammalian cochlear inner hair cells (IHCs) are specialized sensory receptors able to provide dynamic coding of sound signals. This ability is largely conferred by their ribbon synapses, which tether a large number of vesicles at the IHC's presynaptic active zones, allowing high rates of sustained synaptic transmission onto the afferent fibres. How the physiological and morphological properties of ribbon synapses change with age remains largely unknown. Here, we have investigated the biophysical and morphological properties of IHC ribbon synapses in the ageing cochlea (9–12 kHz region) of four mouse strains commonly used in hearing research: early‐onset progressive hearing loss (C57BL/6J and C57BL/6NTac) and ‘good hearing’ strains (C57BL/6NTacCdh23+ and C3H/HeJ). We found that with age, both modiolar and pillar sides of the IHC exhibited a loss of ribbons, but there was an increased volume of those that remained. These morphological changes, which only occurred after 6 months of age, were correlated with the level of hearing loss in the different mouse strains, being most severe for C57BL/6NTac and C57BL/6J, less so for C57BL/6NTacCdh23+ and absent for C3H/HeJ strains. Despite the age‐related reduction in ribbon number in three of the four strains, the size and kinetics of Ca2+‐dependent exocytosis, as well as the replenishment of synaptic vesicles, in IHCs was not affected. The degree of vesicle release at the fewer, but larger, individual remaining ribbon synapses colocalized with the post‐synaptic afferent terminals is likely to increase, indicating the presence of a previously unknown degree of functional compensation in the ageing mouse cochlea

Prospectus, January 18, 2012

NEW SHOWS, EVENTS TO MAKE DEBUTS AT PARKLAND, Parkland Expands Science Course Offerings, National Defense Authorization Act Sparks Debate Among Studetns, Wikipedia, Google to Protest SOPA, 11th Annual Rev. Dr. Martin Luther King Jr. Celebration, Q&A With the Student Government President, Meet the Coffee Professor, Ask Buster: Questions From the Readers, Now\u27s the Time to Save for College, A United States of Europe?, What\u27s Your New Year Resolution?, Cobra Men Beginning to Hit Their Stride, Women\u27s Basketball Continue Strong Seasonhttps://spark.parkland.edu/prospectus_2012/1000/thumbnail.jp

Modelling the effects of the anode work function in PPV LED

Transparent conducting oxides are widely used as the transparent electrode in polymer light emitting diodes (PLEDs). The physical properties of these materials and consequently device performance strongly depend on their processing and surface treatment. The injection of charge from the transparent electrode into the polymer layer occurs by tunnelling through a potential barrier from the electrode to molecules close to it. This barrier is influenced by the difference in the relevant energy levels of electrode material and polymer molecules, the external applied potential, the Coulomb potential of the charges present in the polymer layer and the potential of their image charges on the electrodes, and may also be altered by electrode degradation effects. A better understanding of the effect of varying this potential barrier on the functioning of PLED is necessary to achieve further improvements in these applications. Here we present a theoretical study of the influence of changes in the potential barrier at the transparent electrode, on bipolar charge evolution through thin polymer layers, in the absence of defects and impurity states, while the other electrode functions as an ohmic contact. Results of a mesoscopic model provide insight into bipolar charge injection, charge and recombination distribution throughout the polymer layer, and may suggest new materials and processing methods to optimize these optoelectronic devices.FEDER.Fundação para a Ciência e a Tecnologia (FCT) – Programa Operacional “Ciência , Tecnologia, Inovação” – POCTI/CTM/41574/2001, CONC-REEQ/443/EEI/2005; SFRH/BD/22143/2005

Gravitational Collapse in Higher Dimensional Husain Space-Time

We investigate exact solution in higher dimensional Husain model for a null fluid source with pressure $p$ and density $\rho$ are related by the following relations (i) $p=k\rho$, (ii) $p=k\rho-\frac{B(v)}{\rho^{\alpha}}$ (variable modified Chaplygin) and (iii) $p=k\rho^{\alpha}$ (polytropic). We have studied the nature of singularity in gravitational collapse for the above equations of state and also for different choices of the of the parameters $k$ and $B$ namely, (i) $k=0$, $B=$ constant (generalized Chaplygin), (ii) $B=$ constant (modified Chaplygin). It is found that the nature of singularity is independent of these choices of different equation of state except for variable Chaplygin model. Choices of various parameters are shown in tabular form. Finally, matching of Szekeres model with exterior Husain space-time is done.Comment: 12 latex pages, No figure, RevTex styl

Governance of Offshore IT Outsourcing at Shell Global Functions IT-BAM Development and Application of a Governance Framework to Improve Outsourcing Relationships

The lack of effective IT governance is widely recognized as a key inhibitor to successful global IT outsourcing relationships. In this study we present the development and application of a governance framework to improve outsourcing relationships. The approach used to developing an IT governance framework includes a meta model and a customization process to fit the framework to the target organization. The IT governance framework consists of four different elements (1) organisational structures, (2) joint processes between in- and outsourcer, (3) responsibilities that link roles to processes and (4) a diverse set of control indicators to measure the success of the relationship. The IT governance framework is put in practice in Shell GFIT BAM, a part of Shell that concluded to have a lack of management control over at least one of their outsourcing relationships. In a workshop the governance framework was used to perform a gap analysis between the current and desired governance. Several gaps were identified in the way roles and responsibilities are assigned and joint processes are set-up. Moreover, this workshop also showed the usefulness and usability of the IT governance framework in structuring, providing input and managing stakeholders in the discussions around IT governance