Assessment of the types of public building maintenance contracts in Saudi Arabia

The study revealed that Fixed Price, Cost Plus and Purchased Labour contracts are the top three maintenance contracts adopted whilst Unit Price, Cost Plus A Percentage Fee contracts are alternatives used in the Kingdom. Some other types of maintenance contract were thought to be inappropriate by ministry departments.     

Photo Sequencing

A group of people taking pictures of a dynamic event with their mobile phones is a popular sight. The set of still images obtained this way is rich in dynamic content but lacks accurate temporal information. We propose a method for photo-sequencing—temporally ordering a set of still images taken asynchronously by a set of uncalibrated cameras. Photo-sequencing is an essential tool in analyzing (or visualizing) a dynamic scene captured by still images. The first step of the method detects sets of corresponding static and dynamic feature points across images. The static features are used to determine the epipolar geometry between pairs of images, and each dynamic feature votes for the temporal order of the images in which it appears. The partial orders provided by the dynamic features are not necessarily consistent, and we use rank aggregation to combine them into a globally consistent temporal order of images. We demonstrate successful photo-sequencing on several challenging collections of images taken using a number of mobile phones.     

Numerical simulations of failure behavior around a circular opening in a non-persistently jointed rock mass under biaxial compression

Pre-existing discontinuities change the mechanical properties of rock masses,and further influence failure behavior around an underground opening.In present study,the failure behavior in both Inner and Outer zones around a circular opening in a non-persistently jointed rock mass under biaxial compression was investigated through numerical simulations.First,the micro parameters of the PFC^3D model were carefully calibrated using the macro mechanical properties determined in physical experiments implemented on jointed rock models.Then,a parametrical study was undertaken of the effect of stress condition,joint dip angle and joint persistency.Under low initial stress,the confining stress improves the mechanical behavior of the surrounding rock masses;while under high initial stress,the surrounding rock mass failed immediately following excavation.At small dip angles the cracks around the circular opening developed generally outwards in a step-path failure pattern;whereas,at high dip angles the surrounding rock mass failed in an instantaneous intact rock failure pattern.Moreover,the stability of the rock mass around the circular opening deteriorated significantly with increasing joint persistency.     

2-Transitivity is Insufficient for Local Testability

A basic goal in property testing is to identify a minimal set of features that make a property testable. For the case when the property to be tested is membership in a binary linear error-correcting code, Alon et al. (Trans Inf Theory, 51(11):4032–4039, 2005) had conjectured that the presence of a single low-weight codeword in the dual, and “2-transitivity” of the code (i.e., the code being invariant under a 2-transitive group of permutations on the coordinates of the code) suffice to get local testability. We refute this conjecture by giving a family of error-correcting codes where the coordinates of the codewords form a large field of characteristic two, and the code is invariant under affine transformations of the domain. This class of properties was introduced by Kaufman & Sudan (STOC, 2008) as a setting where many results in algebraic property testing generalize. Our result shows a complementary virtue: This family also can be useful in producing counterexamples to natural conjectures.     

Self-Assembly and Neurotoxicity of β-Amyloid (21–40) Peptide Fragment: The Regulatory Role of GxxxG Motifs

The three GxxxG repeating motifs from the C-terminal region of β-amyloid (Aβ) peptide play a significant role in regulating the aggregation kinetics of the peptide. Mutation of these glycine residues to leucine greatly accelerates the fibrillation process but generates a varied toxicity profile. Using an array of biophysical techniques, we demonstrated the uniqueness of the composite glycine residues in these structural repeats. We used solvent relaxation NMR spectroscopy to investigate the role played by the surrounding water molecules in determining the corresponding aggregation pathway. Notably, the conformational changes induced by Gly³³ and Gly³⁷ mutations result in significantly decreased toxicity in a neuronal cell line. Our results indicate that G³³xxxG³⁷ is the primary motif responsible for Aβ neurotoxicity, hence providing a direct structure–function correlation. Targeting this motif, therefore, can be a promising strategy to prevent neuronal cell death associated with Alzheimer's and other related diseases, such as type II diabetes and Parkinson's.     

On the Effective Deployment of Functional Formal Verification

We examine IBM's exploitation of formal verification using RuleBase—a formal verification tool developed by the IBM Haifa Research Laboratory. The goal of the paper is methodological. We identify an integrated methodology for the deployment of formal verification which involves three complementary modes: architectural verification, block-level verification, and design exploration.     

Languages, scripts, and the environment: Factors in developing concepts of print.

Preschool children bilingual in English and Hebrew were investigated for their understanding of concepts of print by means of two tasks. In the first, children had to understand that a printed word did not change its meaning if it moved to a new location. In the second, children had to make judgments about word length and ignore the size of the named objects. Previous research had shown bilingual French–English and Chinese–English children to excel in the first task, but only older Chinese–English bilinguals had an advantage in the second. The present study extended those results by investigating the effect of writing system in more detail. The study also examined the effect of the language of the environment by conducting parallel studies in environments in which either English or Hebrew was the community language. The results show that the bilingual children in both settings were more advanced than the monolinguals in both tasks and in both settings. (PsycINFO Database Record (c) 2010 APA, all rights reserved)