On Matrix Rigidity and Locally Self-correctable Codes

We describe a new connection between the problem of finding rigid matrices, as posed by Valiant (MFCS 1977), and the problem of proving lower bounds for linear locally correctable codes. Our result shows that proving linear lower bounds on locally correctable codes with super-logarithmic query complexity will give new constructions of rigid matrices. The interest in constructing rigid matrices is their connection to circuit lower bounds.     

Rooted in the home garden and in the nation's landscape: Women and the emerging Hebrew garden in Palestine

In the early 20th century, the Hebrew women in Palestine found the fulfillment of their economic, social, and emotional needs in gardening. Their gardens were women's means of shaping their surroundings, mainly in the family sphere but also in the community sphere (school and kindergarten gardens, kibbutz gardens). The project was an outcome of the shared interests of pioneer women, city dwellers, and Jewish women's organizations, which differed in their social status and life goals, yet shared a common fertile ground. Through the investigation of primary and secondary sources that deal with women, gardens and the history of the Zionist settlement in Palestine, this paper argues that planting gardens was the Hebrew women's modest way of creating a ‘space of their own’, where they nurtured and fostered beauty, productivity, self-esteem, mutual help and friendship, while overcoming class distinction. Meanwhile, in planting gardens, women gained a share in the Zionist nation-building project, which was primarily male dominated.     

A fair server adaptation algorithm for HTTP adaptive streaming using video complexity

Multimedia Tools and Applications - The increasing popularity of online video content and adaptive video streaming services, especially those based on HTTP Adaptive Streaming (HAS) highlights the...     

Automated,Ultra‐Fast Laser‐Drilling of Nanometer Scale Pores and Nanopore Arrays in Aqueous Solutions

The ability to quickly and reliably fabricate nanoscale pore arrays in ultra‐thin membranes such as silicon nitride (Si_xN) is extremely important for the growing field of nanopore biosensing. Laser‐based etching of thin Si_xN membranes immersed in aqueous solutions has recently been demonstrated as a method to produce stable functional pores. Herein, the principal mechanism governing material etching and pore formation using light is investigated. It is found that the process is extremely sensitive to the relative content of Si over N atoms in the amorphous membrane, produced by chemical vapor deposition. Commonly, Si_xN membranes are made to be Si‐rich to increase their mechanical stability, which substantially reduces the material's bandgap and increases the density of Si‐dangling bonds. Hence, even minimal batch‐to‐batch variation may lead to remarkably different etch rates. It is shown that higher Si content results in orders of magnitude faster etching rates. This rate is further accelerated in an alkaline environment allowing on‐demand controlled nanopore formation in about 10 s time even at low laser radiation intensities. These results highlight that photoactivation of the Si_xN by the incident beam is critical to the chemical etching process and can be used to readily produce nanopore arrays at any specific location.     

Study of anisotropy in the properties of material prepared of powdered iron

We have used mathematical modeling with experimental verification of the results to study anisotropy in the properties of materials prepared of powdered iron. In fabrication of the powdered material, anisotropy arises in the structure as a result of the characteristic features of the technology, which affects the options for using the material. We have experimentally studied the degree of anisotropy in materials fabricated from powdered iron with different pressing forces. We propose mathematical models for the macrostructure of the powdered material, and test their adequacy to experimental data. We conclude that the degree of anisotropy in the powder material increases as it is compacted by increased pressing force. The structure of the material at the mesoscopic level after sintering can be considered as transverse isotropic, while the properties (depending on the degree of compaction of the material) can be described by a hexagonal or cubic symmetry system. __________ Translated from Poroshkovaya Metallurgiya, Nos. 3–4(448), pp. 88–97, March–April, 2006.     

Effects of harvest stage and re‐growth on yield,composition, ensilage and in vitro digestibility of new forage sorghum varieties

The effect of growth stage and re‐growth on the nutritional and ensilage characteristics of two new sorghum hybrids, BMR‐101 and Silobuster, and one commercial variety, FS‐5, was examined in this study. Varieties were sampled during the summer at the early heading (EH) stage and were harvested at the soft dough (SD) stage. Additional irrigation enabled autumn re‐growth and a second harvest. Plants of FS‐5 and BMR‐101 were resistant to lodging at EH. However, BMR‐101 and Silobuster suffered from high lodging at the SD stage of the summer harvest. Dry matter (DM) content of FS‐5 and BMR‐101 at EH was below 250 g kg^?1. DM yields of the varieties were similar at the summer harvest and higher than their respective re‐growth cuts. Ensilage DM losses were moderate and similar across varieties. Hemicellulose of SD plants was partly solubilised and most of the water‐soluble carbohydrate fermented, yielding lactic acid, ethanol and volatile fatty acids (VFA), and a pH < 4. In vitro DM digestibility of varieties was similar in summer silages, but lower in the respective re‐growth silages of FS‐5 and BMR‐101, reflecting the higher content of neutral detergent fibre and lignin in the re‐growth silages. The summer plus re‐growth cumulative yields of digestible DM of the respective FS‐5, Silobuster and BMR‐101 silages were 14.7, 16.6 and 14.5 t ha^?1. The commercial variety, FS‐5, may have some advantage over BMR‐101 and Silobuster owing to its relative resistance to lodging in addition to its high yield and good ensilage properties. Copyright © 2005 Society of Chemical Industry