Algorithms for ℓp Low Rank Approximation

We consider the problem of approximating a given matrix by a low-rank matrix so as to minimize the entry-wise ℓp-approximation error, for any P ≥ 1; the case p = 2 is the classical SVD problem. We obtain the first provably good approximation algorithms for this version of low-rank approximation that work for every value of p ≥ 1, including p = σ. Our algorithms are simple, easy to implement, work well in practice, and illustrate interesting tradeoffs between the approximation quality, the running time, and the rank of the approximating matrix

Microstructure and Wear Study of Al 7075-T6/Eggshell/SiC/Al2O3 Hybrid Composites

In present experimental investigation, hybrid aluminium metal matrix composites were fabricated using stir casting technique by infusing eggshell particles (0.5, 1 wt%), SiC particles (1, 1.5 wt%) and Al2O3 particles (1.5, 2.5 wt%) into Al 7075-T6 metal matrix. The developed composites were further characterized for microstructures using FESEM, X-ray diffractometry and EDS techniques. Tribological behaviour investigations were carried out using a pin-on-disk tribometer for comparative study between as-cast Al 7075-T6 alloy and Al-7075-T6/Eggshell/SiC/Al2O3 composites. During dry sliding wear test at room temperature, there was a decrease of 33% in wear rate, 20% in coefficient of friction and 20% in frictional force of composites, whereas in presence of lubricant, the developed composites exhibited maximum reduction of 85% in wear rate, 46% in coefficient of friction and 46% in frictional force as compared to their unreinforced counterparts. Due to augmented tribological properties, fabricated hybrid composites can reasonably be used for lightweight wear-resistant applications

Valorisation of CO 2 into Value-Added Products via Microbial Electrosynthesis (MES) and Electro-Fermentation Technology

Microbial electrocatalysis reckons on microbes as catalysts for reactions occurring at electrodes. Microbial fuel cells and microbial electrolysis cells are well-known in this context; both prefer the oxidation of organic and inorganic matter for producing electricity. Notably, the synthesis of high energy-density chemicals (fuels) or their precursors by microorganisms using bio-cathode to yield electrical energy is called Microbial Electrosynthesis (MES), giving an exceptionally appealing novel way for producing beneficial products from electricity and wastewater. This review accentuates the concept, importance and opportunities of MES, as an emerging discipline at the nexus of microbiology and electrochemistry. Production of organic compounds from MES is considered as an effective technique for the generation of various beneficial reduced end-products (like acetate and butyrate) as well as in reducing the load of CO2 from the atmosphere to mitigate the harmful effect of greenhouse gases in global warming. Although MES is still an emerging technology, this method is not thoroughly known. The authors have focused on MES, as it is the next transformative, viable alternative technology to decrease the repercussions of surplus carbon dioxide in the environment along with conserving energy

Effects of antiplatelet therapy on stroke risk by brain imaging features of intracerebral haemorrhage and cerebral small vessel diseases: subgroup analyses of the RESTART randomised, open-label trial

Background Findings from the RESTART trial suggest that starting antiplatelet therapy might reduce the risk of recurrent symptomatic intracerebral haemorrhage compared with avoiding antiplatelet therapy. Brain imaging features of intracerebral haemorrhage and cerebral small vessel diseases (such as cerebral microbleeds) are associated with greater risks of recurrent intracerebral haemorrhage. We did subgroup analyses of the RESTART trial to explore whether these brain imaging features modify the effects of antiplatelet therapy

CURATION AND MANAGEMENT OF CULTURAL HERITAGE THROUGH LIBRARIES

Libraries, museums and archives hold valuable collections in a variety of media, presenting a vast body of knowledge rooted in the history of human civilisation. These form the repository of the wisdom of great works by thinkers of past and the present. The holdings of these institutions are priceless heritage of the mankind as they preserve documents, ideas, and the oral and written records. To value the cultural heritage and to care for it as a treasure bequeathed to us by our ancestors is the major responsibility of libraries. The past records constitute a natural resource and are indispensable to the present generation as well as to the generations to come. Libraries preserve the documentary heritage resources for which they are primarily responsible. Any loss of such materials is simply irreplaceable. Therefore, preserving this intellectual, cultural heritage becomes not only the academic commitment but also the moral responsibility of the librarians/information scientists, who are in charge of these repositories. The high quality of the papers and the discussion represent the thinking and experience of experts in their particular fields. The contributed papers also relate to the methodology used in libraries in Asia to provide access to manuscripts and cultural heritage. The volume discusses best practices in Knowledge preservation and how to collaborate and preserve the culture. The book also deals with manuscript and archives issues in the digital era. The approach of this book is concise, comprehensively, covering all major aspects of preservation and conservation through libraries. The readership of the book is not just limited to library and information science professionals, but also for those involved in conservation, preservation, restoration or other related disciplines. The book will be useful for librarians, archivists and conservators. We thank the Sunan Kalijaga University, Special Libraries Association- Asian Chapter for their trust and their constant support, all the contributors for their submissions, the members of the Local and International Committee for their reviewing effort for making this publication possible

Pathogenic LRRK2 Mutations Do Not Alter Gene Expression in Cell Model Systems or Human Brain Tissue

Point mutations in LRRK2 cause autosomal dominant Parkinson's disease. Despite extensive efforts to determine the mechanism of cell death in patients with LRRK2 mutations, the aetiology of LRRK2 PD is not well understood. To examine possible alterations in gene expression linked to the presence of LRRK2 mutations, we carried out a case versus control analysis of global gene expression in three systems: fibroblasts isolated from LRRK2 mutation carriers and healthy, non-mutation carrying controls; brain tissue from G2019S mutation carriers and controls; and HEK293 inducible LRRK2 wild type and mutant cell lines. No significant alteration in gene expression was found in these systems following correction for multiple testing. These data suggest that any alterations in basal gene expression in fibroblasts or cell lines containing mutations in LRRK2 are likely to be quantitatively small. This work suggests that LRRK2 is unlikely to play a direct role in modulation of gene expression, although it remains possible that this protein can influence mRNA expression under pathogenic cicumstances

Nanoporous carbon materials with enhanced supercapacitance performance and non-aromatic chemical sensing with C1/C2 alcohol discrimination

We have investigated the textural properties, electrochemical supercapacitances and vapor sensing performances of bamboo-derived nanoporous carbon materials (NCM). Bamboo, an abundant natural biomaterial, was chemically activated with phosphoric acid at 400 °C and the effect of impregnation ratio of phosphoric acid on the textural properties and electrochemical performances was systematically investigated. Fourier transform-infrared (FTIR) spectroscopy confirmed the presence of various oxygen-containing surface functional groups (i.e. carboxyl, carboxylate, carbonyl and phenolic groups) in NCM. The prepared NCM are amorphous in nature and contain hierarchical micropores and mesopores. Surface areas and pore volumes were found in the range 218–1431 m2 g−1 and 0.26–1.26 cm3 g−1, respectively, and could be controlled by adjusting the impregnation ratio of phosphoric acid and bamboo cane powder. NCM exhibited electrical double-layer supercapacitor behavior giving a high specific capacitance of c.256 F g−1 at a scan rate of 5 mV s−1 together with high cyclic stability with capacitance retention of about 92.6% after 1000 cycles. Furthermore, NCM exhibited excellent vapor sensing performance with high sensitivity for non-aromatic chemicals such as acetic acid. The system would be useful to discriminate C1 and C2 alcohol (methanol and ethanol)

Nanoporous carbon materials with enhanced supercapacitance performance and non-aromatic chemical sensing with C₁/C₂ alcohol discrimination

<p>We have investigated the textural properties, electrochemical supercapacitances and vapor sensing performances of bamboo-derived nanoporous carbon materials (NCM). Bamboo, an abundant natural biomaterial, was chemically activated with phosphoric acid at 400 °C and the effect of impregnation ratio of phosphoric acid on the textural properties and electrochemical performances was systematically investigated. Fourier transform-infrared (FTIR) spectroscopy confirmed the presence of various oxygen-containing surface functional groups (i.e. carboxyl, carboxylate, carbonyl and phenolic groups) in NCM. The prepared NCM are amorphous in nature and contain hierarchical micropores and mesopores. Surface areas and pore volumes were found in the range 218–1431 m² g⁻¹ and 0.26–1.26 cm³ g⁻¹, respectively, and could be controlled by adjusting the impregnation ratio of phosphoric acid and bamboo cane powder. NCM exhibited electrical double-layer supercapacitor behavior giving a high specific capacitance of <i>c</i>.256 F g⁻¹ at a scan rate of 5 mV s⁻¹ together with high cyclic stability with capacitance retention of about 92.6% after 1000 cycles. Furthermore, NCM exhibited excellent vapor sensing performance with high sensitivity for non-aromatic chemicals such as acetic acid. The system would be useful to discriminate C₁ and C₂ alcohol (methanol and ethanol).</p