Dynamics of three-body correlations in quenched unitary Bose gases

We investigate dynamical three-body correlations in the Bose gas during the earliest stages of evolution after a quench to the unitary regime. The development of few-body correlations is theoretically observed by determining the two- and three-body contacts. We find that the growth of three-body correlations is gradual compared to two-body correlations. The three-body contact oscillates coherently, and we identify this as a signature of Efimov trimers. We show that the growth of three-body correlations depends non-trivially on parameters derived from both the density and Efimov physics. These results demonstrate the violation of scaling invariance of unitary bosonic systems via the appearance of log-periodic modulation of three-body correlations

The Management of Extrahepatic Portal Vein Aneurysms: Observe or Treat?

A case of a 70 year old man who was found to have an extrahepatic portal vein aneurysm during an evaluation for hematuria is reported. Extrahepatic portal vein aneurysms are rare with only twenty cases reported in the literature. Typically, patients present with hemorrhage requiring surgical exploration or the aneurysm is discovered during evaluation of another abdominal process. Management includes careful follow-up in the asymptomatic patient without underlying liver disease or portal hypertension

Demographics, referral patterns and management of patients accessing the Welsh Eye Care Service

BACKGROUND: The Primary Eyecare Acute Referral Service (PEARS) and the Wales Eye Health Examination (WEHE) operate as enhanced optometry services for patients residing in Wales, enabling the examination of a patient presenting with an acute eye problem (PEARS) or the examination of patients at higher risk of eye disease (WEHE). The purpose of the study is to assess the demographics of patients accessing these services, referral patterns and clinical management in one Health Board in Wales (Aneurin Bevan University Health Board). METHODS: Information from 2302 patients accessing the services was prospectively collected. The following information was obtained: type of examination (PEARS or WEHE), patient age, gender, self-referral or general practitioner (GP) referral and clinical management (no further action, monitor by optometrist or ophthalmic medical practitioner [OMP], refer to the Hospital Eye Service [HES], or refer to GP). RESULTS: There were 1791 (77.8 %) PEARS examinations and 511 (22.2 %) WEHE. There were 1379 (59.9 %) females with a mean age of 58.61 (±19.75) and 923 (40.1 %) males with a mean age of 56.11 (±20.42). The majority of patients were self-referrals compared to GP-referrals (1793 [77.9 %] versus 509 [22.1 %] respectively). Sub-analysis indicated similar numbers of self-referrals compared to GP-referrals for the WEHE only (297 [58.1 %] versus 214 [41.9 %] respectively) but greater numbers of self-referrals for the PEARS examinations only (1496 [83.5 %] versus 295 [16.5 %] respectively). For management, 75 % of patients were monitored by their optometrist or OMP, 17 % required referral to the HES and 8 % required referral to their GP. CONCLUSIONS: Higher numbers of females accessed both PEARS and WEHE services and the majority of patients self-referred. These findings have important implications for public health campaigns both for targeting specific groups (e.g. male patients) and increasing awareness among GPs

Site-specific Mutants of Oncomodulin: 1H NMR and optical stopped-flow studies of the effect on the metal binding properties of an Asp59 → Glu59 substitution in the calcium-specific site

Abstract High resolution 1H nuclear magnetic resonance spectroscopy and optical stopped-flow techniques have been used to study the metal binding properties of a site-specific mutant of bacterial recombinant oncomodulin in which glutamate has replaced a liganding aspartate at position 59 in the CD calcium-binding site. In particular we have followed the replacement of calcium by lutetium in bacterial recombinant oncomodulin and D59E oncomodulin to provide a measure of the protein's preferences for metal ions of different ionic radii. The result of the Asp----Glu substitution is to make the mutant oncomodulin more similar to rat parvalbumin in terms of its relative CD- and EF-domain affinities for lutetium(III), that is to increase its affinity for metal ions with smaller ionic radii. This finding supports the original hypothesis that the presence of Asp at sequence position 59 is an important factor in the reduced preference of the CD site of oncomodulin for smaller metals such as magnesium (Williams, T. C., Corson, D. C., Sykes, B. D., and MacManus, J. P. (1987) J. Biol. Chem. 262, 6248-6256). However, our studies show that both the CD and the EF sites are affected by this single residue substitution suggesting that many factors play a role in the metal binding affinity and interaction between the two sites

A Distributed Shared Key Generation Procedure Using Fractional Keys

We present a new class of distributed key generation and recoveryalgorithms suitable for group communication systems where the groupmembership is either static or slowly time-varying, and must be tightlycontrolled. The proposed key generation approach allows entities whichmayhave only partial trust in each other to jointly generate a shared keywithout the aid of an external third party. The group collectivelygenerates and maintains a dynamic group parameter, and the shared key isgenerated using a strong, one-way function of this parameter. This schemealso provides perfect forward secrecy. The validity of key generation canbe checked using verifiable secret sharing techniques. The key retrievalmethod does not require the keys to be stored in an external retrievalcenter. We note that many Internet-based applications may have theserequirements. Fulfillment of these requirements is realized through theuse of fractional keys--a distributed technique recently developed toenhance the security of distributed systems in a non-cryptographicmanner

Dynamic Elgamal Public Key Generation with Tight Binding

We present a new distributed, group ElGamal public key generation algorithm which also permits maintenance of a group-specific, dynamic, individual ElGamal public key infrastructure. We parameterize the group with a time-varying quantity that serves as a distributed mechanism for controlling key generation privilege. Our scheme can be viewed as an alternative to polynomial schemes where, at the time of the secret construction step, there has to be a third party or a black box to combine the shares. Also, in polynomial schemes, at the time of combining,the individual shares of the secret have to be revealed to the third party. In our scheme, the common secret can be generated without ever exposing the individual shares constructing it. We note that many of the recently proposed distributed key management schemes need such group keys for certification and signing purposes.3rd Annual Conference on Advanced Telecommunications and Information Distribution Research Program (ATIRP)</i

A Scalable Extension of Group Key Management Protocol

This paper presents a robust, scalable extension to the recently proposed multicast Group Key Management Protocol (GKMP) ([1], [2]), in terms of security administration. The GKMP has two major security related problems: (a) lack of any mechanism to remove a compromised group administrator, and (b) lack of scalability. We are able to remove a compromised single panel member from generating the group keys by setting the panel members with shared authority to generate the group keys. We then introduce the sub-controllers who have all the functionalities of the group control panel except the authority to generate the group keys. The sub-control panel helps scalability of the network in terms of the security operations. The sub-controllers are chosen using a threshold-based clustering algorithm. This paper was presented at the "ATIRP ARL Federated Laboratory 2nd Annual Conference," Feb. 5-6, 1998, University of Maryland, College Park Campus.</I