Issues in digital preservation: towards a new research agenda

Digital Preservation has evolved into a specialized, interdisciplinary research discipline of its own, seeing significant increases in terms of research capacity, results, but also challenges. However, with this specialization and subsequent formation of a dedicated subgroup of researchers active in this field, limitations of the challenges addressed can be observed. Digital preservation research may seem to react to problems arising, fixing problems that exist now, rather than proactively researching new solutions that may be applicable only after a few years of maturing. Recognising the benefits of bringing together researchers and practitioners with various professional backgrounds related to digital preservation, a seminar was organized in Schloss Dagstuhl, at the Leibniz Center for Informatics (18-23 July 2010), with the aim of addressing the current digital preservation challenges, with a specific focus on the automation aspects in this field. The main goal of the seminar was to outline some research challenges in digital preservation, providing a number of "research questions" that could be immediately tackled, e.g. in Doctoral Thesis. The seminar intended also to highlight the need for the digital preservation community to reach out to IT research and other research communities outside the immediate digital preservation domain, in order to jointly develop solutions

Crystal nucleation and cluster-growth kinetics in a model glass under shear

Crystal nucleation and growth processes induced by an externally applied shear strain in a model metallic glass are studied by means of nonequilibrium molecular dynamics simulations, in a range of temperatures. We observe that the nucleation-growth process takes place after a transient, induction regime. The critical cluster size and the lag-time associated with this induction period are determined from a mean first-passage time analysis. The laws that describe the cluster growth process are studied as a function of temperature and strain rate. A theoretical model for crystallization kinetics that includes the time dependence for nucleation and cluster growth is developed within the framework of the Kolmogorov-Johnson-Mehl-Avrami scenario and is compared with the molecular dynamics data. Scalings for the cluster growth laws and for the crystallization kinetics are also proposed and tested. The observed nucleation rates are found to display a nonmonotonic strain rate dependency

Effect of frozen storage on fat soluble vitamins content in fish fillets

Fat-soluble vitamins content (all-trans-retinol, alpha-tocopherol and cholecalciferol) in edible tissue of Bluefish (Pomatomus saltatrix), a typical Black sea pelagic fish, and in Rainbow trout (Oncorhynchus mykiss), a typical farmed freshwater fish, were determined and compared on raw state and after frozen storage. The sample preparation procedure includes saponification and consequent extraction of fat-soluble vitamins with n-hexane.The extract was dried under nitrogen flow and redissolved in methanol. HPLC analysis of methanolic samples was performed on ODS2 Hypersil (250x4,6, 5um) column with a mobile phase of methanol:water = 97:3. The quantification of fat-soluble vitamins was by the method of standard addition. Retinol and cholecalciferol were monitored by UV detection and alpha-tocopherol was detected by fluorescence.The retinol and cholecalciferol contents in fresh edible tissue of Black sea Bluefish (38.5±2.4 μg.100g-1ww and 11.2±1.2 μg.100g-1ww, respectively) were close to values in the freshwater fish Rainbow trout (58.9±2.6 μg.100g-1ww and 14.9±1.1 μg.100g-1ww, respectively). Alpha-tocopherol content was several fold higher in Rainbow trout (1648.9±68.8 μg.100g-1ww) than in Black sea Bluefish (427.1±37.1 μg.100g-1ww).Long period of storage affected mostly retinol and alpha-tocopherol contents in two fish species. While cholecalciferol content remained almost unchanged

Assessment of Proximate and Bioactive Lipid Composition of Black Sea Mussels (M. galloprovincialis) from Bulgaria

Farmed marine mussels from genera Mytilus are important for the human diet by providing high levels of proteins, omega-3 polyunsaturated fatty acids (PUFAs), fat soluble vitamins and carbohydrates. Recently, black mussels are commercially important species from the Bulgarian Black Sea. The aim of this study was to assess the seasonal changes in proximate composition and to focus on the lipid bioactive components such as fatty acids, cholesterol, fat-soluble vitamins (A, E and D3), and carotenoids (astaxanthin, beta-carotene) in farmed mussels (M. galloprovincialis) from the northern part of the Bulgarian Black Sea coast. All analyzed samples presented high protein and low lipid content. The fatty acids (FA) profile was characterized by the highest amount of PUFA, as 22:6 omega-3 (n-3) dominated, regardless of the seasons. In all seasons, the content of n-3 was significantly higher than the omega-6 PUFA. The amounts of cholesterol were in the range 62.3 (summer) to 78 (autumn) mg 100−1 g ww. The highest amounts of vitamin D3 (3.1 μg 100−1 g ww), vitamin E (2525 μg 100−1 g ww), astaxanthin (0.470 mg 100−1 g ww), and beta-carotene (0.445 mg 100−1 g ww) were found in the summer season. The studied mussel aquaculture from Bulgaria presented a high beneficial potential in all seasons in terms of human health protection

User Studies for Digital Library Development

As the information environment becomes increasingly electronic, digital libraries have proliferated, but the focus has often been on innovations in technology and not the user. Research and analysis of users is essential to fine-tune the content and approach of digital libraries to the diverging requirements and expectations of incredibly varied communities and to ensure libraries are effective, accessible and sustainable in the long term. This book provides a clear overview of the user studies domain and user issues in digital libraries

Amnion formation in the mouse embryo: the single amniochorionic fold model

<p>Abstract</p> <p>Background</p> <p>Despite the detailed knowledge obtained over the last decade on the molecular regulation of gastrulation in amniotes, the process of amnion development has been poorly described and illustrated in mice, and conflicting descriptions exist. Understanding the morphogenesis and development not only of the early mouse embryo, but also of its extraembryonic tissues, is crucial for correctly interpreting fate-mapping data and mouse mutants with gastrulation defects. Moreover, the recent isolation from amnion of cells with stem cell features further argues for a better understanding of the process of amnion formation. Here, we revisit the highly dynamic process of amnion formation in the mouse. Amnion development starts early during gastrulation and is intimately related to the formation of the exocoelom and the expansion of the amniotic fold. The authoritative description involves the fusion of two amniotic folds, a big posterior and a smaller anterior fold. We challenged this 'two amniotic folds' model by performing detailed histomorphological analyses of dissected, staged embryos and 3D reconstructions using historical sections.</p> <p>Results</p> <p>A posterior fold of extraembryonic ectoderm and associated epiblast is formed early during gastrulation by accumulation of extraembryonic mesoderm posterior to the primitive streak. Previously called the "posterior amniotic fold", we rename it the "amniochorionic fold" (ACF) because it forms both amnion and chorion. Exocoelom formation within the ACF seems not to involve apoptosis within the mesoderm. The ACF and exocoelom expand without disrupting the anterior junction of epiblast, extraembryonic ectoderm and visceral endoderm. No separate anterior fold is formed; its absence was confirmed in 3D reconstructions. Amnion and chorion closure is eccentric, close to the anterior margin of the egg cylinder: we name it the "anterior separation point".</p> <p>Conclusions</p> <p>Here, we reconcile previous descriptions of amnion formation and provide new nomenclature, as well as an animation, that clarify and emphasize the arrangement of the tissues that contribute to amnion development and the dynamics of the process. According to our data, the amnion and the chorion are formed by a single amniochorionic fold initiated posteriorly. Finally, we give an overview on mutant mouse models with impaired amnion development.</p

Satb2 Regulates Callosal Projection Neuron Identity in the Developing Cerebral Cortex

SummarySatb2 is a DNA-binding protein that regulates chromatin organization and gene expression. In the developing brain, Satb2 is expressed in cortical neurons that extend axons across the corpus callosum. To assess the role of Satb2 in neurons, we analyzed mice in which the Satb2 locus was disrupted by insertion of a LacZ gene. In mutant mice, β-galactosidase-labeled axons are absent from the corpus callosum and instead descend along the corticospinal tract. Satb2 mutant neurons acquire expression of Ctip2, a transcription factor that is necessary and sufficient for the extension of subcortical projections by cortical neurons. Conversely, ectopic expression of Satb2 in neural stem cells markedly decreases Ctip2 expression. Finally, we find that Satb2 binds directly to regulatory regions of Ctip2 and induces changes in chromatin structure. These data suggest that Satb2 functions as a repressor of Ctip2 and regulatory determinant of corticocortical connections in the developing cerebral cortex

BLACK SEA RAPANA VENOSA – A PROMISING SOURCE OF ESSENTIAL LIPIDS

Background: A diet rich in seafood has been linked to a variety of health benefits. While worldwide overfishing results in declining fish stocks, the growing demand for alternative sources of marine lipids has been expected. Rapana venosa (veined Rapa whelk) has become valuable seafood with nutritional and economic importance in the Black Sea region. Purpose: The aim of the present study was to provide knowledge about biologically active lipids in Black Sea Rapana venosa, harvested in the region of Varna. Material/Methods: Lipid classes were separated and purified by column and thin-layer chromatography. The saponifiable lipid fraction was derivatized into fatty acid methyl esters (FAMEs) and analysed by gas chromatography–mass spectrometry (GC-MS). Non-saponifiable lipids were identified by high pressure liquid chromatography coupled with UV/Vis and fluorescence detectors (HPLC-UV-FL). Results: Rapana venosa was characterized by low lipid content (0.50 g.100g-1 ww) with beneficial PUFA/SFA and n-6/n-3 ratios and high content of vitamin D3 and astaxanthin. Lipids comprised mainly of polar lipids. Polyunsaturated fatty acids represented more than 50% of total fatty acids, most abundant being from the omega-3 series. Sum of EPA and DHA accounted at 40.8% of total fatty acids. Lipid quality indices indicated the good anti-atherogenic and atni-trombogenic properties (AI and TI < 1) of rapana meat. Conclusions: The study revealed that Rapana venosa from the Black Sea is a good source of high quality marine lipids and presents а high potential for developing functional foods and/or dietary supplements with beneficial health effects