The impact of Corporate Social Responsibility (CSR) policies on perceptions and behavioral intension of Greek consumers

During the last five years Greece has witnessed the exposure of an unprecedented number of corporate related events that had a significant impact on the public opinion (huge financial scandals, various corruption accusations, etc). These events dramatically increased the negative perception of consumers towards large companies operating in Greece. Corporate Social Responsibility (CSR) may be considered as an effective initiative that protects and strengthens the image and reputation of implementing companies, especially at a time that their status has been severely damaged by numerous distressing reports. The World Business Council for Sustainable Development (2000) defines CSR as a business commitment that supports sustainable economic development and, at the same time, contributes to the quality of life of employees, their families, the local community and society in general. Companies that implement CSR try to establish a positive business reputation and enhance the corporate brand name by taking actions that lead in the development of a competitive advantage, while at the same time contribute to the demands of various third parties. These companies shift from solely focusing on profits and tend to include financial, environmental and social goals in their core business strategies. Therefore, many researchers argue that the CSR policy is an activity mutually beneficial for both the business and society. However, several doubts about the effectiveness of these policies are being expressed. The purpose of the present study is to measure the perceptions of consumers about Greek Large Companies (GLC) and examine the influence of the implementation of CSR policies on consumers’ perception and consumers’ behavioral intention. The results of the quantitative research (N=454) highlighted the negative perceptions of Greeks towards GLC but, at the same time, revealed the statistically significant positive effect of CSR policies on consumers’ perceptions and behavioral intention.Corporate Social Responsibility, CSR, consumer’s perceptions, behavioral intention, Greece

Function-specific schemes for verifiable computation

An integral component of modern computing is the ability to outsource data and computation to powerful remote servers, for instance, in the context of cloud computing or remote file storage. While participants can benefit from this interaction, a fundamental security issue that arises is that of integrity of computation: How can the end-user be certain that the result of a computation over the outsourced data has not been tampered with (not even by a compromised or adversarial server)? Cryptographic schemes for verifiable computation address this problem by accompanying each result with a proof that can be used to check the correctness of the performed computation. Recent advances in the field have led to the first implementations of schemes that can verify arbitrary computations. However, in practice the overhead of these general-purpose constructions remains prohibitive for most applications, with proof computation times (at the server) in the order of minutes or even hours for real-world problem instances. A different approach for designing such schemes targets specific types of computation and builds custom-made protocols, sacrificing generality for efficiency. An important representative of this function-specific approach is an authenticated data structure (ADS), where a specialized protocol is designed that supports query types associated with a particular outsourced dataset. This thesis presents three novel ADS constructions for the important query types of set operations, multi-dimensional range search, and pattern matching, and proves their security under cryptographic assumptions over bilinear groups. The scheme for set operations can support nested queries (e.g., two unions followed by an intersection of the results), extending previous works that only accommodate a single operation. The range search ADS provides an exponential (in the number of attributes in the dataset) asymptotic improvement from previous schemes for storage and computation costs. Finally, the pattern matching ADS supports text pattern and XML path queries with minimal cost, e.g., the overhead at the server is less than 4% compared to simply computing the result, for all our tested settings. The experimental evaluation of all three constructions shows significant improvements in proof-computation time over general-purpose schemes

Function of synthetic Hox transcription factors "in vivo" and the quantitative study of their molecular interactions with nuclear DNA at the single-molecule level in live cells

Over a century of research, invested in providing an answer to the fundamental question of how a single diploid cell constructs a whole organism, has placed Drosophila in the fore scene of developmental biology and has allowed us to merge the knowledge acquired from embryology with that of molecular biology and genetics. The assignment of differential morphological and functional characteristics to the different body parts during development is largely mastered by Homeobox (Hox) genes which are involved in the specification of segmental identity along the anterior-posterior (AP) axis of bilateral animals. Hox genes encode transcription factors that contain the Homeodomain (HD), a helix-turn-helix DNA-binding domain, the conservation of which spans long evolutionary distances as the one between yeast and humans. The biological function of Hox transcription factors has been studied extensively to date and much is known about their role in development at the genetic, molecular and structural level. The molecular interactions of various HDs with their DNA binding sites have been precisely dissected in vitro and numerous developmentally important Hox downstream genes (effector genes) have been identified, providing the link between segmental specification and pattern formation, originally in Drosophila and subsequently in other animals. However, the conservation of the HD in metazoans, albeit providing meaningful evidence for the interpretation of molecular evolutionary relationships between animal phyla, has been proven an obstacle in explaining the specificity of Hox target selection in vivo. Since all Hox orthologs and paralogs bind very similar regulatory sequences in vivo, it is challenging to explain how they simultaneously regulate differentially the formation of diverse body parts during development. The finding of a limited number of Hox cofactors has allowed us to take first steps towards solving this riddle, but a satisfactory explanation has not been provided yet. In the present study we have constructed synthetic Drosophila Hox genes which encode a small carboxy-terminal (C-terminal) portion [tyrosine-proline-tryptophan-methionine (YPWM) motif, HD and C-terminus] of the full-length protein and have examined their function as transcriptional regulators genetically and their interactions with nuclear DNA in live cells, using methods with single-molecule sensitivity, quantitative imaging and Fluorescence Correlation Spectroscopy (FCS). We have found that both Antennapedia (Antp) and Sex combs reduced (Scr) synthetic genes are functional in vivo and that the synthetic transcription factors find their binding sites primarily by multiple association/dissociation events, the rapidity of which is largely owed to electrostatic interactions. Synthetic Scr genes exhibited specific function in vivo by inducing homeotic transformations in the embryo (allowing the formation of an additional pair of salivary glands) and in the adult fly (transforming the adult antenna into a prothoracic tarsus). They repressed antennal-specific genes, ectopically activated leg-specific genes in the antennal imaginal disc and bound DNA specifically both in vitro and in vivo. Their transformation capacity was found to be enhanced as compared to the full-length protein, suggesting that the amino-terminal (N-terminal) portion of the protein contributes quantitative, rather than qualitative, effects in Scr-mediated transcription. Having proven their functionality in vivo, we used the synthetic Scr genes as tools for the study of HD-DNA interactions in live salivary gland cells, which express Scr normally during development, and thus represent a native Scr environment. By means of quantitative imaging, using Avalanche Photo-Diodes (APDs) with single-molecule sensitivity, we studied the molecular distribution and dynamics of synthetic transcription factors in polytene nuclei. We could distinguish wild type from mutant peptides directly by APD imaging, on the basis of their differential association with nuclear DNA, and study by FCS their movement and interactions with chromatin at the molecular level. This has been possible using the expression “leakage” of the heat shock protein 70 (hsp70)-minimal promoter of the Upstream Activating Sequences (UAS)-constructs and its responsiveness to heat-shock, features, which facilitated measurements at low, physiologically-relevant levels. Thus, we were able to titrate the concentration of the transcription factor in live nuclei and to construct transcription factor-DNA binding curves in order to analyze the underlying chemical interactions kinetically. Using a simple two-step model in which non-specific interactions are followed by specific interactions, we derived experimentally the in vivo macroscopic equilibrium dissociation constant of the HD-DNA complex for specific and non-specific interactions, as well as the corresponding DNA-binding constants by numerical simulations. Functional analysis was also performed using synthetic Antp genes. These were also able to confer gene-specific homeotic transformations during embryonic and larval development, such as head-to-trunk transformations reflected in the embryonic cuticle, repression and activation of markers in the embryo, as well as antenna-to-mesothoracic-tarsus transformations in the adult, mediated by repression of antennal-specific genes and ectopic activation of leg-specific genes in the antennal imaginal disc. At the same time we examined the role of the Antp YPWM motif in transcriptional regulation and found it important for both activation and repression. We also investigated the importance of linker size between the YPWM motif and the HD (naturally varying in Antp splicing variants) and showed that linkers of different size preferentially favor or limit the function of the protein either as a transcriptional repressor or as an activator. Taken together, our results show that synthetic Hox genes are functional in vivo. They exhibit gene-specific phenotypes, comparable to or enhanced over their full-length counterparts. This suggests that the long N-terminal portion of Hox transcription factors is not required for specificity, but for enhancing or limiting the strength of the transcriptional response. Our study also proposes synthetic genes as important tools for synthetic biology, since smaller but functional peptides might bear advantages for biomedically relevant applications, as compared to larger proteins. In addition, we establish an experimental platform for the quantitative study of transcription factor-DNA binding in vivo, devoid of overexpression and/or destructive observation of molecules and molecular interactions. We derive by FCS and quantitative imaging for the first time the in vivo HD-DNA binding constant and unravel the molecular interactions of the HD with chromatin in unprecedented detail. Our work might be used as a starting point for the dissection of transcription factor-DNA interactions in vivo which are relevant for development and disease

Verifiable Random Functions (VRFs)

A Verifiable Random Function (VRF) is the public-key version of a keyed cryptographic hash. Only the holder of the private key can compute the hash, but anyone with public key can verify the correctness of the hash. VRFs are useful for preventing enumeration of hash-based data structures. This document specifies several VRF constructions that are secure in the cryptographic random oracle model. One VRF uses RSA and the other VRF uses Eliptic Curves (EC).https://datatracker.ietf.org/doc/draft-irtf-cfrg-vrf/First author draf

NSEC5, DNSSEC authenticated denial of existence

The Domain Name System Security Extensions (DNSSEC) introduced two resource records (RR) for authenticated denial of existence: the NSEC RR and the NSEC3 RR. This document introduces NSEC5 as an alternative mechanism for DNSSEC authenticated denial of existence. NSEC5 uses verifiable random functions (VRFs) to prevent offline enumeration of zone contents. NSEC5 also protects the integrity of the zone contents even if an adversary compromises one of the authoritative servers for the zone. Integrity is preserved because NSEC5 does not require private zone-signing keys to be present on all authoritative servers for the zone, in contrast to DNSSEC online signing schemes like NSEC3 White Lies.https://datatracker.ietf.org/doc/draft-vcelak-nsec5/First author draf