Identity Signature Research Articles

Mycoplasma haemocanis – the canine hemoplasma and its feline counterpart in the genomic era

Mycoplasma haemocanis is a hemotrophic mycoplasma (hemoplasma), blood pathogen that may cause acute disease in immunosuppressed or splenectomized dogs. The genome of the strain Illinois, isolated from blood of a naturally infected dog, has been entirely sequenced and annotated to gain a better understanding of the biology of M. haemocanis. Its single circular chromosome has 919 992 bp and a low G + C content (35%), representing a typical mycoplasmal genome. A gene-by-gene comparison against its feline counterpart, M. haemofelis, reveals a very similar composition and architecture with most of the genes having conserved synteny extending over their entire chromosomes and differing only by a small set of unique protein coding sequences. As in M. haemofelis, M. haemocanis metabolic pathways are reduced and apparently rely heavily on the nutrients afforded by its host environment. The presence of a major percentage of its genome dedicated to paralogous genes (63.7%) suggests that this bacterium might use antigenic variation as a mechanism to evade the host’s immune system as also observed in M. haemofelis genome. Phylogenomic comparisons based on average nucleotide identity (ANI) and tetranucleotide signature suggest that these two pathogens are different species of mycoplasmas, with M. haemocanis infecting dogs and M. haemofelis infecting cats.

An Effective Mutual Authentication Scheme for Hierarchical Mobile IP

In order to improve the efficiency and security of the authentication for Hierarchical Mobile IP protocol, we propose a novel authentication scheme, which introduced identity signature and digital envelope to authenticate the sender and receiver of the registration packet. Theoretically prove that the scheme is an effective mutual authentication scheme, and improve the security and resist security attacks.

Communication of collective identity in secret social groups: Hypothesis of a holographic signature of member affiliation

This work describes the theoretical basis for a non‐phonemic method of detecting membership in secret social groups, such as cults, criminal gangs, drug cartels and terrorist cells. Beginning with the basic sociological proposition that every social group develops a distinctive socio‐cultural order, it is postulated that the primary features of group identity will be encoded, via a multi‐level socio‐psycho‐physiological process, into the field of bio‐emotional relations connecting group members. This information is communicated in all group‐related interactions by a holographic‐like process and recorded in the members’ brains as a unique signature of group affiliation. The group’s identity signature should be present in measurements of interaction between members as a latent commonality marking group affiliation. It is hypothesized that the identity signature is enfolded as a hologram in the energy spectra of vocal interactions among group members. In clandestine groups, the effort to remain hidden should enhance the signal strength of the identity signature. It is expected that detection of unknown members can be achieved using the spectral commonality identified in the analysis of recordings of vocal interactions among known members as a reference signature for comparison with those of the vocal spectra of suspected or potential members.

Detecting the Identity Signature of Secret Social Groups: Holographic Processes and the Communication of Member Affiliation

The principles of classical and quantum holography are used to develop the theoretical basis for a non-phonemic method of detecting membership in secret social groups, such as cults, criminal gangs, drug cartels, and terrorist cells. Grounded in the basic sociological premise that every group develops a distinctive sociocultural order, the theory postulates that the primary features of a group's collective identity will be encoded, via a multilevel socio-psycho-physiological process, into the field of bio-emotional relations connecting group members. The principles of classical holography (Gabor 1948) are used to describe how this information is recorded in the members' brains and communicated in interaction by a holographic-like process as a tacit signature of group affiliation—a constancy in group-related interactions. It is hypothesized that the identity signature is enfolded as a hologram in the energy spectra of vocal interactions among group members. The principles of quantum holography (Gabor 1946) are used to provide a description of the group's ongoing interactions as a dynamic process—a continuous, quantized series of snapshots (quantum holograms). Linked together, two forms of holography provide a model of how the group's collective identity evolves and is communicated over time to its members, as the group adapts to the ever-changing reality of its endogenous and exogenous circumstances. Using spectral analysis techniques, it should be possible to detect the group's identity signature in the recordings of relatively small samples of vocal interactions. In clandestine groups, the effort to remain hidden actually enhances the signal strength of the identity signature. It is predicted, therefore, that detection of unknown members can be achieved by using the spectral commonality identified in the analysis of recordings of vocal interactions among known members as a reference signature for comparison with those of the vocal spectra of suspected or potential members.

Female recognition and assessment of males through scent

Scents play key roles in mediating sexual behaviour in many vertebrates, both in the recognition of opposite sex conspecifics and in assessing the suitability of different individuals as potential mates. The recognition and assessment that underlies female attraction to male scents involves an important interaction between the main and accessory (vomeronasal) olfactory systems. Female mice gain information through the vomeronasal system on nasal contact with a scent source that is essential to stimulate attraction to an individual male's scent. Three highly polymorphic multigene families contribute involatile proteins and peptides to mouse scents that are detected through specific vomeronasal receptors during contact with scent. Major urinary proteins (MUPs) provide an individual genetic identity signature that underlies individual recognition and assessment of male competitive ability, kin recognition to avoid inbreeding, and genetic heterozygosity assessment. Familiar mates are recognised in the context of pregnancy block using MHC peptides, while exocrine-gland secreting peptides (ESPs) are likely to play additional roles in sexual assessment. By associating this involatile information in individual male scents, gained on initial scent contact, with the individual male's airborne volatile signature detected simultaneously through the main olfactory system, females subsequently recognise and are attracted by the individual male's airborne volatile signature alone. This allows much more rapid recognition of scents from familiar animals without requiring physical contact or processing through the vomeronasal system. Nonetheless, key information that induces attraction to a male's scent is held in involatile components detected through the vomeronasal system, allowing assessment of the genetic identity and attractiveness of each individual male.

Limited variation in the major urinary proteins of laboratory mice

Individual variation in a specialised set of scent communication proteins, the major urinary proteins (MUPs), provides a genetic identity signature that underlies individual and kin recognition, and the assessment of heterozygosity in wild house mice. Here we examine the extent to which MUP variation is retained among 30 classical strains of laboratory mice from three main lineages (Castle, C57, Swiss). Normal wild-type variation in urinary MUP pattern appears to have been lost at an early stage in the derivation of the classical laboratory strains. All strains from the Castle and Swiss lineages shared the same “individual” MUP pattern, consistent with common ancestry from very few founders, while those from the C57 lineage shared a different pattern. Notably, individual variation in MUP pattern was no greater within the Swiss outbred ICR (CD-1) strain than typical for inbred strains. Total urinary protein concentration varied considerably between even closely related substrains, together with minor variation in the relative amount of each MUP isoform expressed, although the functional significance of such quantitative variation in MUP expression has yet to be established. Expression was 2–8 fold higher among males, while a MUP expressed by most male but not female wild mice was expressed by C57 males but variably among Castle and Swiss males and occasionally by females in some strains. The lack of normal variation in MUP patterns within and between strains has important implications for the use of laboratory mice in behavioural or neurophysiological research investigating social recognition or mate choice.

A rationally engineered misacylating aminoacyl-tRNA synthetase

Information transfer from nucleic acid to protein is mediated by aminoacyl-tRNA synthetases, which catalyze the specific pairings of amino acids with transfer RNAs. Despite copious sequence and structural information on the 22 tRNA synthetase families, little is known of the enzyme signatures that specify amino acid selectivities. Here, we show that transplanting a conserved arginine residue from glutamyl-tRNA synthetase (GluRS) to glutaminyl-tRNA synthetase (GlnRS) improves the K(M) of GlnRS for noncognate glutamate. Two crystal structures of this C229R GlnRS mutant reveal that a conserved twin-arginine GluRS amino acid identity signature cannot be incorporated into GlnRS without disrupting surrounding protein structural elements that interact with the tRNA. Consistent with these findings, we show that cumulative replacement of other primary binding site residues in GlnRS, with those of GluRS, only slightly improves the ability of the GlnRS active site to accommodate glutamate. However, introduction of 22 amino acid replacements and one deletion, including substitution of the entire primary binding site and two surface loops adjacent to the region disrupted in C229R, improves the capacity of Escherichia coli GlnRS to synthesize misacylated Glu-tRNA(Gln) by 16,000-fold. This hybrid enzyme recapitulates the function of misacylating GluRS enzymes found in organisms that synthesize Gln-tRNA(Gln) by an alternative pathway. These findings implicate the RNA component of the contemporary GlnRS-tRNA(Gln) complex in mediating amino acid specificity. This role for tRNA may persist as a relic of primordial cells in which the evolution of the genetic code was driven by RNA-catalyzed amino acid-RNA pairing.

Gait recognition based on dynamic region analysis

Gait Energy Image (GEI) has been proved to be an effective identity signature in gait recognition. But previous approaches only treat this 2D image representation as a holistic feature and neglect the intrinsic dynamic characteristics of gait patterns. In this paper, we use variation analysis to obtain the dynamic region in GEI which reflects the walking manner of an individual. Based on this analysis, a dynamics weight mask is constructed to enhance the dynamic region and suppress the noises on the unimportant regions. The obtained gait representation called enhanced GEI (EGEI) is then represented in low dimensional subspace by Gabor-based discriminative common vectors analysis. We test the proposed approach on the USF HumanID Gait Database. Experimental results prove its effectiveness in terms of recognition rate.

The Genetic Basis of Individual-Recognition Signals in the Mouse

The major histocompatibility complex (MHC) is widely assumed to be a primary determinant of individual-recognition scents in many vertebrates [1-6], but there has been no functional test of this in animals with normal levels of genetic variation. Mice have evolved another polygenic and highly polymorphic set of proteins for scent communication, the major urinary proteins (MUPs) [7-12], which may provide a more reliable identity signature ([13, 14] and A.L. Sherborne, M.D.T., S. Paterson, F.J., W.E.R.O., P. Stockley, R.J.B., and J.L.H., unpublished data). We used female preference for males that countermark competitor male scents [15-17] to test the ability of wild-derived mice to recognize individual males differing in MHC or MUP type on a variable genetic background. Differences in MHC type were not used for individual recognition. Instead, recognition depended on a difference in MUP type, regardless of other genetic differences between individuals. Recognition also required scent contact, consistent with detection of involatile components through the vomeronasal system [6, 18]. Other differences in individual scent stimulated investigation but did not result in individual recognition. Contrary to untested assumptions of a vertebrate-wide mechanism based largely on MHC variation, mice use a species-specific [12] individual identity signature that can be recognized reliably despite the complex internal and external factors that influence scents [2]. Specific signals for genetic identity recognition in other species now need to be investigated.

It's not what you say but the way you say it: Matching faces and voices.

Recent studies have shown that the face and voice of an unfamiliar person can be matched for identity. Here the authors compare the relative effects of changing sentence content (what is said) and sentence manner (how it is said) on matching identity between faces and voices. A change between speaking a sentence as a statement and as a question disrupted matching performance, whereas changing the sentence itself did not. This was the case when the faces and voices were from the same race as participants and speaking a familiar language (English; Experiment 1) or from another race and speaking an unfamiliar language (Japanese; Experiment 2). Altering manner between conversational and clear speech (Experiment 3) or between conversational and casual speech (Experiment 4) was also disruptive. However, artificially slowing (Experiment 5) or speeding (Experiment 6) speech did not affect cross-modal matching performance. The results show that bimodal cues to identity are closely linked to manner but that content (what is said) and absolute tempo are not critical. Instead, prosodic variations in rhythmic structure and/or expressiveness may provide a bimodal, dynamic identity signature.

Face recognition under arbitrary illumination using illuminated exemplars

Recently, the importance of face recognition has been increasingly emphasized since popular CCD cameras are distributed to various applications. However, facial images are dramatically changed by lighting variations, so that facial appearance changes caused serious performance degradation in face recognition. Many researchers have tried to overcome these illumination problems using diverse approaches, which have required a multiple registered images per person or the prior knowledge of lighting conditions. In this paper, we propose a new method for face recognition under arbitrary lighting conditions, given only a single registered image and training data under unknown illuminations. Our proposed method is based on the illuminated exemplars which are synthesized from photometric stereo images of training data. The linear combination of illuminated exemplars can represent the new face and the weighted coefficients of those illuminated exemplars are used as identity signature. We make experiments for verifying our approach and compare it with two traditional approaches. As a result, higher recognition rates are reported in these experiments using the illumination subset of Max-Planck Institute face database and Korean face database.

Usability evaluation of multi-modal biometric verification systems

As a result of the evolution in the field of biometrics, a new breed of techniques and methods for user identity recognition and verification has appeared based on the recognition and verification of several biometric features considered unique to each individual. Signature and voice characteristics, facial features, and iris and fingerprint patterns have all been used to identify a person or just to verify that the person is who he/she claims to be. Although still relatively new, these new technologies have already reached a level of development that allows its commercialization. However, there is a lack of studies devoted to the evaluation of these technologies from a user-centered perspective. This paper is intended to promote user-centered design and evaluation of biometric technologies. Towards this end, we have developed a platform to perform empirical evaluations of commercial biometric identity verification systems, including fingerprint, voice and signature verification. In this article, we present an initial empirical study in which we evaluate, compare and try to get insights into the factors that are crucial for the usability of these systems.

Image-based face recognition under illumination and pose variations

We present an image-based method for face recognition across different illuminations and poses, where the term image-based means that no explicit prior three-dimensional models are needed. As face recognition under illumination and pose variations involves three factors, namely, identity, illumination, and pose, generalizations in all these three factors are desired. We present a recognition approach that is able to generalize in the identity and illumination dimensions and handle a given set of poses. Specifically, the proposed approach derives an identity signature that is illumination- and pose-invariant, where the identity is tackled by means of subspace encoding, the illumination is characterized with a Lambertian reflectance model, and the given set of poses is treated as a whole. Experimental results using the Pose, Illumination, and Expression (PIE) database demonstrate the effectiveness of the proposed approach.

Tansley Review No. 113

Caesium (Cs) is a Group I alkali metal with chemical properties similar to potassium (K). It is present in solution as the monovalent cation Cs+. Concentrations of the stable caesium isotope 133Cs in soils occur up to 25 μg g−1 dry soil. This corresponds to low micromolar Cs+ concentrations in soil solutions. There is no known role for Cs in plant nutrition, but excessive Cs can be toxic to plants. Studies of the mechanism of Cs+ uptake are important for understanding the implications arising from releases of radioisotopes of Cs, which are produced in nuclear reactors and thermonuclear explosions. Two radioisotopes of Cs (134Cs and 137Cs) are of environmental concern owing to their relatively long half‐lives, emissions of β and γ radiation during decay and rapid incorporation into biological systems. The soil concentrations of these radioisotopes are six orders of magnitude lower than those of 133Cs. Early physiological studies demonstrated that K+ and Cs+ competed for influx to excised roots, suggesting that the influx of these cations to root cells is mediated by the same molecular mechanism(s). The molecular identity and/or electrophysiological signature of many K+ transporters expressed in the plasma membrane of root cells have been described. The inward‐rectifying K+ (KIR), outward‐rectifying K+ (KOR) and voltage‐insensitive cation (VIC) channels are all permeable to Cs+ and, by analogy with their bacterial counterparts, it is likely that ‘high‐affinity’ K+/H+ symporters (tentatively ascribed here to KUP genes) also transport Cs+. By modelling cation fluxes through these transporters into a stereotypical root cell, it can be predicted that VIC channels mediate most (30–90%) of the Cs+ influx under physiological conditions and that the KUP transporters mediate the bulk of the remainder. Cation influx through KIR channels is likely to be blocked by extracellular Cs+ under typical ionic conditions in the soil. Further simulations suggest that the combined Cs+ influxes through VIC channels and KUP transporters can produce the characteristic ‘dual isotherm’ relationship between Cs+ influx to excised roots and external Cs+ concentrations below 200 μM. Thus, molecular targets for modulating Cs+ influx to root cells have been identified. This information can be used to direct future genetic modification of plants, allowing them to accumulate more, or less, Cs and thereby to remediate contaminated sites. contents Summary 241 I. introduction: caesium in the environment 242 II. uptake of caesium by plant roots 243 III. molecular mechanisms catalysing caesium uptake 245 IV. modelling caesium influx to root cells 249 V. perspective 253 Acknowledgements 254

Realisation of a minimum-knowledge identification and signature scheme

A minimum-knowledge scheme allows a claimant to prove its identity to a verifier without disclosing any secret information. Minimum-knowledge schemes, incorporating identity verification, signature generation and verification, are generally based on interactive proofs. The Ohta-Okamoto minimum-knowledge identification and signature scheme is characterised by a good balance between the claimant's storage requirements and the time to perform a verification. This makes it particularly suitable for use with minimum storage devices such as smart cards. This paper presents a realisation of an Ohta-Okamoto based minimum knowledge and signature scheme, ranging over identity verification, signature generation and verification. The modular arithmetic functions, such as: multiplication, division, exponentiation and multiplicative inverse, as well as prime number generation, pseudo random number generation and hashing function are detailed. An analysis of the realised scheme is presented, including a comparison with the Fiat-Shamir identification scheme.