Geometry theorem proving forms a major and challenging component in the K-12 mathematics curriculum. A particular difficult task is to add auxiliary constructions (i.e., additional lines or points) to aid proof discovery. Although there exist many intelligent tutoring systems proposed for geometry proofs, few teach students how to find auxiliary constructions. And the few exceptions are all lim...

Films of oriented bacteriorhodopsin have been formed in polyvinyl alcohol with excellent optical quality. Images with high contrast have been impressed and erased on these films. Second-harmonic microscopy has been used to read the image on a bacteriorhodopsin-polyvinyl alcohol film without erasure. The potential of these films for molecular information storage and computation is discussed.

The Domain Name System (DNS) is a critical component of the Internet infrastructure as it maps human-readable names to IP addresses. Injecting fraudulent mappings allows an attacker to divert users from intended destinations to those of an attacker’s choosing. In this paper, we measure the Internet’s vulnerability to DNS record injection attacks—including a new attack we uncover. We find that r...

porous media has interesting features in compared with free flame combustion due to the extended of the lean flammability limits and lower emissions. advanced new generation of internal combustion (ic) engines are expected to have far better emissions levels both gaseous and particulate matter, at the same time having far lower fuel consumption on a wide range of operating condition. these crit...

to study the effect of different concentrations of potassium in thenutrient solution and water stress on the quality and quantity yield of lilium la cv.termoli, a pot experiment was conducted based on completely randomized design in sand and perlite medium (50:50) in three levels of potassium (kfree, 6 mm k and and 12 mm k in hoagland solution) with three replications. in the present study, the...

the present study reports an efficient protocol for isolation and regeneration of protoplasts from callus of fritillaria imperialis l. there is no published method recommended for protoplast isolation and regeneration from fritillaria imperialis l. a range of factors, which influence the success of isolation and regeneration of f. imperialis protoplasts, were investigated. from the results obta...

the lack of variation in antifungal drugs, and the misuse or inappropriate use usually causes resistant strains of the yeast in human’s normal flora. unfortunately, a large number of candida infection cases in immunosuppressed patients with insufficient treatment eventually can cause patient's death. the aim of this study was to evaluate the in vitro conventional antifungal azole compounds with...

aflatoxin contamination of food and feedstuffs is a serious economic and health hazard. over a period of two years, 35 samples of raw pistachio nuts collected from different parts of iran were analysed for the presence of aflatoxigenic strains of the aspergillus flavus group. eighty-five isolates of a.flavus and a.parasiticuswere identified based on specific yello-orange pigment production in t...

background: bone marrow mesenchymal stem cells (mscs) are one of the undifferentiated multipotential cell sources of human body. methods: mscs have the capacity to form a variety of cell types, especially chondrocytes and osteocytes. learning about responses of mscs to external milieu and chemical factors such as ph could recommend new approaches for preparation of suitable scaffolds for bone a...