Biogenic silica and silicic acid benthic fluxes of a North-eastern Atlantic Abyssal Locality

Within the framework of the EU-funded BENGAL programme, the effects of seasonality on biogenic silica early diagenesis have been studied at the Porcupine Abyssal Plain (PAP), an abyssal locality located in the northeast Atlantic Ocean. Nine cruises were carried out between August 1996 and August 1998. Silicic acid (DSi) increased downward from 46.2 to 213 µM (mean of 27 profiles). Biogenic silica (BSi) decreased from ca. 2% near the sediment-water interface to <1% at depth. Benthic silicic acid fluxes as measured from benthic chambers were close to those estimated from non-linear DSi porewater gradients. Some 90% of the dissolution occurred within the top 5.5 cm of the sediment column, rather than at the sediment-water interface and the annual DSi efflux was close to 0.057 mol Si/m**2/yr. Biogenic silica accumulation was close to 0.008 mol Si/m**2/yr and the annual opal delivery reconstructed from sedimentary fluxes, assuming steady state, was 0.065 mol Si/m**2/yr. This is in good agreement with the mean annual opal flux determined from sediment trap samples, averaged over the last decade (0.062 mol Si/m**2/yr). Thus ca. 12% of the opal flux delivered to the seafloor get preserved in the sediments. A simple comparison between the sedimentation rate and the dissolution rate in the uppermost 5.5 cm of the sediment column suggests that there should be no accumulation of opal in PAP sediments. However, by combining the BENGAL high sampling frequency with our experimental results on BSi dissolution, we conclude that non-steady state processes associated with the seasonal deposition of fresh biogenic particles may well play a fundamental role in the preservation of BSi in these sediments. This comes about though the way seasonal variability affects the quality of the biogenic matter reaching the seafloor. Hence it influences the intrinsic dissolution properties of the opal at the seafloor and also the part played by non-local mixing events by ensuring the rapid transport of BSi particles deep into the sediment to where saturation is reached.

ACE research vignette 002 : competing through service innovation - the case of project-oriented firms

This series of research vignettes is aimed at sharing current and interesting research findings from our team of international Entrepreneurship researchers. In this vignette, Dr Sandeep Salunke shares insights from his research on project-oriented firms.

ACE research briefing paper 002: learning and adaptation in the business creation process

This year marks the completion of data collection for year three (Wave 3) of the CAUSEE study. This report uses data from the first three years and focuses on the process of learning and adaptation in the business creation process. Most start-ups need to change their business model, their product, their marketing plan, their market or something else about the business to be successful. PayPal changed their product at least five times, moving from handheld security, to enterprise apps, to consumer apps, to a digital wallet, to payments between handhelds before finally stumbling on the model that made the a multi-billion dollar company revolving around email-based payments. PayPal is not alone and anecdotes abounds of start-ups changing direction: Sysmantec started as an artificial intelligence company, Apple started selling plans to build computers and Microsoft tried to peddle compilers before licensing an operating system out of New Mexico. To what extent do Australian new ventures change and adapt as their ideas and business develop? As a longitudinal study, CAUSEE was designed specifically to observe development in the venture creation process. In this research briefing paper, we compare development over time of randomly sampled Nascent Firms (NF) and Young Firms(YF), concentrating on the surviving cases. We also compare NFs with YFs at each yearly interval. The 'high potential' over sample is not used in this report.

Diário da Constituinte [gravação de vídeo] : [programa n. 002]

Instalação das Comissões da Assembleia Nacional Constituinte (ANC). A Comissão da Soberania e dos Direitos e Garantias do Homem e da Mulher foi a primeira comissão instalada e foi eleito como Presidente o Dep. Mário Assad, como 1º Vice-Presidente o Dep. Aécio Neves da Cunha e como 2ª Vice-Presidente a Deputada Anna Maria Rattes e como Relator o Senador José Paulo Bisol. Entrevista com populares nas ruas.

Asesoría en joyería, departamento de Antioquia, junio de 2.002. Técnicas de elaboración de cordones con aplicación de hilos en filigrana.

15 hojas : Ilustraciones.

Structural And Surface Morphological Investigation Of Formation Stages Of Highly (002) Oriented Zno Films On Glass Substrates By Spray Pyrolysis Method

ZnO thin films were coated on amorphous glass substrate at various temperatures in the range 160-500 0C by spray pyrolysis method. The as deposited films were characterised by using XRD and SEM. Wurtzite phase of ZnO was formed at a substrate temperature of 400 0C, highly oriented (002) phase was developed with respect to increase of substrate temperature from 450 to 500 0C. Morphological and growth mode of these films were analyzed with respect to structural orientation of films from wurtzite to highly (002) oriented phase. Present study reveals that substrate temperature was one of the important parameters which determine the crystalline quality, population of defects, grain size, orientation and morphology of the films