Crypto topics and applications II

In this chapter we continue the exposition of crypto topics that was begun in the previous chapter. This chapter covers secret sharing, threshold cryptography, signature schemes, and finally quantum key distribution and quantum cryptography. As in the previous chapter, we have focused only on the essentials of each topic. We have selected in the bibliography a list of representative items, which can be consulted for further details. First we give a synopsis of the topics that are discussed in this chapter. Secret sharing is concerned with the problem of how to distribute a secret among a group of participating individuals, or entities, so that only predesignated collections of individuals are able to recreate the secret by collectively combining the parts of the secret that were allocated to them. There are numerous applications of secret-sharing schemes in practice. One example of secret sharing occurs in banking. For instance, the combination to a vault may be distributed in such a way that only specified collections of employees can open the vault by pooling their portions of the combination. In this way the authority to initiate an action, e.g., the opening of a bank vault, is divided for the purposes of providing security and for added functionality, such as auditing, if required. Threshold cryptography is a relatively recently studied area of cryptography. It deals with situations where the authority to initiate or perform cryptographic operations is distributed among a group of individuals. Many of the standard operations of single-user cryptography have counterparts in threshold cryptography. Signature schemes deal with the problem of generating and verifying electronic) signatures for documents.Asubclass of signature schemes is concerned with the shared-generation and the sharedverification of signatures, where a collaborating group of individuals are required to perform these actions. A new paradigm of security has recently been introduced into cryptography with the emergence of the ideas of quantum key distribution and quantum cryptography. While classical cryptography employs various mathematical techniques to restrict eavesdroppers from learning the contents of encrypted messages, in quantum cryptography the information is protected by the laws of physics.

Heat transfer measurements on the first experimental layer of the FIRE II reentry vehicle in expansion tubes

The present study focused on simulating a trajectory point towards the end of the first experimental heatshield of the FIRE II vehicle, at a total flight time of 1639.53s. Scale replicas were sized according to binary scaling and instrumented with thermocouples for testing in the X1 expansion tube, located at The University of Queensland. Correlation of flight to experimental data was achieved through the separation, and independent treatment of the heat modes. Preliminary investigation indicates that the absolute value of radiant surface flux is conserved between two binary scaled models, whereas convective heat transfer increases with the length scale. This difference in the scaling techniques result in the overall contribution of radiative heat transfer diminishing to less than 1% in expansion tubes from a flight value of approximately 9-17%. From empirical correlation's it has been shown that the St √Re number decreases, under special circumstances, in expansion tubes by the percentage radiation present on the flight vehicle. Results obtained in this study give a strong indication that the relative radiative heat transfer contribution in the expansion tube tests is less than that in flight, supporting the analysis that the absolute value remains constant with binary scaling.

The analysis of large scale data taken from the world groundnut (Arachis hypogaea L.) germplasm collection. II. Two-way data with mixed data types

As a sequel to a paper that dealt with the analysis of two-way quantitative data in large germplasm collections, this paper presents analytical methods appropriate for two-way data matrices consisting of mixed data types, namely, ordered multicategory and quantitative data types. While various pattern analysis techniques have been identified as suitable for analysis of the mixed data types which occur in germplasm collections, the clustering and ordination methods used often can not deal explicitly with the computational consequences of large data sets (i.e. greater than 5000 accessions) with incomplete information. However, it is shown that the ordination technique of principal component analysis and the mixture maximum likelihood method of clustering can be employed to achieve such analyses. Germplasm evaluation data for 11436 accessions of groundnut (Arachis hypogaea L.) from the International Research Institute of the Semi-Arid Tropics, Andhra Pradesh, India were examined. Data for nine quantitative descriptors measured in the post-rainy season and five ordered multicategory descriptors were used. Pattern analysis results generally indicated that the accessions could be distinguished into four regions along the continuum of growth habit (or plant erectness). Interpretation of accession membership in these regions was found to be consistent with taxonomic information, such as subspecies. Each growth habit region contained accessions from three of the most common groundnut botanical varieties. This implies that within each of the habit types there is the full range of expression for the other descriptors used in the analysis. Using these types of insights, the patterns of variability in germplasm collections can provide scientists with valuable information for their plant improvement programs.

Macrophonics II

Macrophonics II presents new Australian work emerging from the leading edge of performance interface research. The program addresses the emerging dialogue between traditional media and emerging digital media, as well as dialogues across a broad range of musical traditions. Recent technological developments are causing a complete reevaluation of the relationships between media and genres in art, and Macrophonics II presents a cross-section of responses to this situation. Works in the program foreground an approach to performance that integrates sensors with novel performance control devices, and/or examine how machines can be made musical in performance. The program presents works by Australian artists Donna Hewitt, Julian Knowles and Wade Marynowsky, with choreography by Avril Huddy and dance performance by Lizzie and Zaimon Vilmanis. From sensor-based microphones and guitars, through performance a/v, to post-rock dronescapes, movement inspired works and experimental electronica, Macrophonics II provides a broad and engaging survey of new performance approaches in mediatised environments. Initial R&D for the work was supported by a range of institutions internationally, including the Australia Council for the Arts, Arts Queensland, STEIM (Holland) and the Nes Artist Residency (Iceland).

Mechanisms of sulfide ion oxidation during cyanidation. Part II : Surface catalysis by pyrite

The mechanisms and the reaction products for the oxidation of sulfide ions in the presence of pyrite have been established. When the leach solution contains free sulfide ions, oxidation occurs via electron transfer from the sulfide ion to dissolved oxygen on the pyrite mineral surface, with polysulfides being formed as an intermediate oxidation product. In the absence of cyanide, the polysulfides are further oxidised to thiosulfate, whilst with cyanide present, thiocyanate and sulfite are also formed from the reaction of polysulfides with cyanide and dissolved oxygen. Polysulfide chain length has been shown to affect the final reaction products of polysulfide oxidation by dissolved oxygen. The rate of pyrite catalysed sulfide ion oxidation was found to be slower in cyanide solutions compared to cyanide free solutions. Mixed potential measurements indicated that the reduction of oxygen at the pyrite surface is hindered in the presence of cyanide. The presence of sulfide ions was also found to activate the pyrite surface, increasing its rate of oxidation by oxygen. This effect was particularly evident in the presence of cyanide; in the presence of sulfide the increase in total sulfur from pyrite oxidation was 2.3 mM in 7 h, compared to an increase of <1 mM in the absence of sulfide over 24 h.

Yhh1p/Cft1p directly links poly(A) site recognition and RNA polymerase II transcription termination

RNA polymerase II (pol II) transcription termination requires co‐transcriptional recognition of a functional polyadenylation signal, but the molecular mechanisms that transduce this signal to pol II remain unclear. We show that Yhh1p/Cft1p, the yeast homologue of the mammalian AAUAAA interacting protein CPSF 160, is an RNA‐binding protein and provide evidence that it participates in poly(A) site recognition. Interestingly, RNA binding is mediated by a central domain composed of predicted β‐propeller‐forming repeats, which occurs in proteins of diverse cellular functions. We also found that Yhh1p/Cft1p bound specifically to the phosphorylated C‐terminal domain (CTD) of pol II in vitro and in a two‐hybrid test in vivo. Furthermore, transcriptional run‐on analysis demonstrated that yhh1 mutants were defective in transcription termination, suggesting that Yhh1p/Cft1p functions in the coupling of transcription and 3′‐end formation. We propose that direct interactions of Yhh1p/Cft1p with both the RNA transcript and the CTD are required to communicate poly(A) site recognition to elongating pol II to initiate transcription termination.

Improvement of the mode II interface fracture toughness of glass fiber reinforced plastics/aluminum laminates through vapor grown carbon fiber interleaves

The effects of acid treatment, vapor grown carbon fiber (VGCF) interlayer and the angle, i.e., 0° and 90°, between the rolling stripes of an aluminum (Al) plate and the fiber direction of glass fiber reinforced plastics (GFRP) on the mode II interlaminar mechanical properties of GFRP/Al laminates were investigated. The experimental results of an end notched flexure test demonstrate that the acid treatment and the proper addition of VGCF can effectively improve the critical load and mode II fracture toughness of GFRP/Al laminates. The specimens with acid treatment and 10 g m−2 VGCF addition possess the highest mode II fracture toughness, i.e., 269% and 385% increases in the 0° and 90° specimens, respectively compared to those corresponding pristine ones. Due to the induced anisotropy by the rolling stripes on the aluminum plate, the 90° specimens possess 15.3%–73.6% higher mode II fracture toughness compared to the 0° specimens. The improvement mechanisms were explored by the observation of crack propagation path and fracture surface with optical, laser scanning and scanning electron microscopies. Moreover, finite element analyses were carried out based on the cohesive zone model to verify the experimental fracture toughness and to predict the interface shear strength between the aluminum plates and GFRP laminates.

Dispersion of zero valent iron nanoparticles onto bentonites and the decolourization of orange II

Nano Zero valent iron (Fe0) were reported as an effective material for azo dye removal, however, similar to other nano-materials, ultra-fine powder has a strong tendency to agglomerate into larger particles, resulting in an adverse effect on both effective surface area and catalyst performance. Here we report nano sized Fe0 particles dispersed onto the surface of natural bentonites. X-ray diffraction was used to study the sample phases. Scanning electron microscopy and transmission electron microscopy were applied to study the morphology and morphological changes. Spherical individual Fe0 particles were observed after dispersion onto bentonites, and these samples were used for orange II (OII) decolourization with wide working pH range. Higher reactivity is attributed to good dispersion of Fe0 particles on clay minerals’ surface. This study is significant for providing novel modified clay based catalyst materials for the decolourization of azo dye contaminants from wastewater.

Iron(II) spin transition complexes with dendritic ligands, Part I

The ligands G1- and G2-oligo (benzyl ether) (PBE) dendrons and their iron(II) complexes [Fe(Gn-PBE)3]A2·xH2O (with n = 1, 2 and A = triflate, tosylate) were prepared. The magnetic properties of the complexes were investigated by a SQUID magnetometer. All complexes exhibit gradual spin transition below room temperature. At very low temperatures the magnetic behaviour reflects zero-field splitting (ZFS) effects. 57Fe-Mössbauer spectroscopy was performed to distinguish between ZFS of high spin species and spin state conversion into the low spin state. Further characterisation was carried out by thermogravimetric analysis (TGA) and FT-IR spectroscopy. Structural features have been determined by powder XRD measurements.

Iron(II) spin-transition complexes with dendritic ligands, part II

The dendritic triazole-based complexes \[Fe(G1-BOC)3](triflate) 2·xH2O (1; G1-BOC = tert-butyl {3-\[3-(3-tert- butoxycarbonylaminopropyl)-5-(\[1,2,4]triazol-4-ylcarbamoyl)-phenyl]propyl} carbamate, triflate = CF3SO3-), \[Fe(G1-BOC) 3]-(tosylate)2·xH2O(2;tosylate = p-CH3PhSO3-),\[Fe(G1-DPBE)3]-(triflate) 2·xH2O {3; G1-DPBE = 3,5-bis(3,5- didodecaoxybenzyloxy)-N-\[1,2,4]triazol-4-ylbenzamide}, \[Fe(G1-DPBE) 3]-(tosylate)2·xH2O (4) and \[Fe(G1-DPBE)3](BF4)2·xH2O (5) were designed and synthesized. Magnetic and thermal properties of these novel complexes were characterized by magnetic susceptibility measurements, 57Fe Mössbauer spectroscopy and thermogravimetric analysis or differential scanning calorimetry, respectively. All dendritic complexes under study show different spin-transition behaviour with respect to the nature of different dendritic ligands and counteranions. Complexes 1 and 2 have pronounced effects of a spin-state change during the first heating process and gradual spintransition properties for further temperature treatments, whereas 3 and 4 exhibited a very sharp spin-state change in the first heating procedures. Complex 5 showed a gradual spin-transition curve. In this paper, we report how the magnetic properties of these complexes are correlated with noncoordinated water molecules and their effects on spin states.

Achieving enterprise integration through software customization : part II-enacting the strategy

In part 1 of this update, we put forward the argument that integration in ERP based environments can be achieved in ways other than adopting a software configuration only approach. We drew on evidence from two large ERP implementations to show how, despite the cost implications, some customization, if carefully managed, could prove helpful. In this, the final part of the update, we discuss the benefits, and potential pitfalls, involved in enacting a non-standard based integration strategy. This requires attention to a) broadening the integration definition; b) bringing legacy practices forward and c) developing a customization based integration strategy.

Kirsten ras mutations in patients with colorectal cancer : the ‘RASCAL II’ study

Researchers worldwide with information about the Kirsten ras (Ki-ras) tumour genotype and outcome of patients with colorectal cancer were invited to provide that data in a schematized format for inclusion in a collaborative database called RASCAL (The Kirsten ras in-colorectal-cancer collaborative group). Our results from 2721 such patients have been presented previously and for the first time in any common cancer, showed conclusively that different gene mutations have different impacts on outcome, even when the mutations occur at the same site on the genome. To explore the effect of Ki-ras mutations at different stages of colorectal cancer, more patients were recruited to the database, which was reanalysed when information on 4268 patients from 42 centres in 21 countries had been entered. After predetermined exclusion criteria were applied, data on 3439 patients were entered into a multivariate analysis. This found that of the 12 possible mutations on codons 12 and 13 of Kirsten ras, only one mutation on codon 12, glycine to valine, found in 8.6% of all patients, had a statistically significant impact on failure-free survival (P = 0.004, HR 1.3) and overall survival (P = 0.008, HR 1.29). This mutation appeared to have a greater impact on outcome in Dukes’ C cancers (failure-free survival, P = 0.008, HR 1.5; overall survival P = 0.02, HR 1.45) than in Dukes’ B tumours (failure-free survival, P = 0.46, HR 1.12; overall survival P = 0.36, HR 1.15). Ki-ras mutations may occur early in the development of pre-cancerous adenomas in the colon and rectum. However, this collaborative study suggests that not only is the presence of a codon 12 glycine to valine mutation important for cancer progression but also that it may predispose to more aggressive biological behaviour in patients with advanced colorectal cancer.

Disturbed microtubule function and induction of micronuclei by chelate complexes of mercury(II)

Interactions of mercury(II) with the microtubule network of cells may lead to genotoxicity. Complexation of mercury(II) with EDTA is currently being discussed for its employment in detoxification processes of polluted sites. This prompted us to re-evaluate the effects of such complexing agents on certain aspects of mercury toxicity, by examining the influences of mercury(II) complexes on tubulin assembly and kinesin-driven motility of microtubules. The genotoxic effects were studied using the micronucleus assay in V79 Chinese hamster fibroblasts. Mercury(II) complexes with EDTA and related chelators interfered dose-dependently with tubulin assembly and microtubule motility in vitro. The no-effect-concentration for assembly inhibition was 1 μM of complexed Hg(II), and for inhibition of motility it was 0.05 μM, respectively. These findings are supported on the genotoxicity level by the results of the micronucleus assay, with micronuclei being induced dose-dependently starting at concentrations of about 0.05 μM of complexed Hg(II). Generally, the no-effect-concentrations for complexed mercury(II) found in the cell-free systems and in cellular assays (including the micronucleus test) were identical with or similar to results for mercury tested in the absence of chelators. This indicates that mercury(II) has a much higher affinity to sulfhydryls of cytoskeletal proteins than to this type of complexing agents. Therefore, the suitability of EDTA and related compounds for remediation of environmental mercury contamination or for other detoxification purposes involving mercury has to be questioned.