The Two-Pion Exchange NN-Potential in Nuclear Matter and Nuclear Stability

A meson exchange model of the $\pi\pi$ interaction which fits free $\pi\pi$ scattering data is used to calculate the interactions of pions in nuclear matter as a function of nuclear density. Polarization of the nuclear medium by the pions results in a marked increase in the s-wave $\pi\pi$ attraction at low energy. The influence of this effect on the nucleon-nucleon interaction is a corresponding increase with density of the $NN$ central potential due to the exchange of two correlated pions, resulting in an $NN$ interaction which fails to saturate. A possible mechanism for restoring the theoretical stability of nuclear matter is explored and found to be effective

Chirally Constraining the ππ\pi \pi Interaction in Nuclear Matter

A general prescription for the construction of $\pi \pi$ interaction potentials which preserve scattering length constraints from chiral symmetry when iterated in scattering equations is derived. The prescription involves only minor modifications of typical meson-exchange models, so that coupling constants and cut-off masses in the models are not greatly affected. Calculations of $s$-wave $\pi \pi$ scattering amplitudes in nuclear matter for two models are compared with those for similar models which violate the chiral constraint. While the prescription tends to suppress the accumulation of the near sub-threshold strength of the $\pi \pi$ interaction, an earlier conjecture that amplitudes which satisfy chiral constraints will not exhibit an instability towards $\pi \pi~s-$wave pair condensation appears to be incorrect. At the same time, however, conventional $\pi \pi$ interaction models which fit scattering data well can readily be adjusted to avoid the instability in nuclear matter without recourse to exotic mechanisms.Comment: 20 pages RevTeX and 5 figures (uuencoded .ps-files

Meson exchange model for pseudoscalar meson-meson scattering

A dynamical model for pseudoscalar-pseudoscalar meson scattering based on meson exchange, suitable for use in a variety of low- and intermediate-energy mesonic interactions, has been constructed and applied to ππ and kπ scattering with good quantitative results. The model includes both s- and t-channel exchange, and is found to require pseudoscalar-pseudoscalar coupling to a scalar octet to fit the high energy s-wave phases in the I = 0 ππ channel and in the channel. Coupling of the ππ and KK̄ channels is found to play a crucial role in explaining the S∗(975) resonanc

Blockchain GDPR Data Compliance through Container Utilisation

This research presents an investigation of the utilization of data containerization on a Blockchain network, as this will allow for the compliance of GDPR. Blockchain is a form of technology that is cryptographically protected and is therefore an immutable system by design. This is achieved through cryptographical calculation of entered data from which a hash is generated this can then be used like a signature as the same content has to be present to gain the same hash again. A Hash is a long string of letters and numbers. This hash is then stored inside a ‘block’ of information within the Blockchain’s ledger. These blocks are all linked together through the storing of a previous block’s hash in the newest entry, this is to ensure that the blocks of information can be cryptographically checked and guarantees that the data has not been tampered with or modified. Blockchain’s flaw lies in the fact that any inputted data cannot be removed, otherwise, the chain is broken. This is a clear breach of GDPR if user data is stored inside it; GDPR is a regulation that affects the handling, collection and management of user data and information. The specific article which affects Blockchain in relation to GDPR is Article 17, which states all members of the EU, and UK (United Kingdom) as the law was ratified into UK law, have the right to erasure and to be forgotten. This causes issues for Blockchain, as data cannot be modified or removed from an existing Blockchain network, without invalidating the Blockchain. This is due to Blockchain’s design, as an incorrect entry, or more specifically, a cryptographic hash, on the ledger invalidates the Blockchain. Containerisation solves this issue by storing data that needs to be removable inside of a separate DUR16610086 Mitch J. Durso4storage method. For the purposes of this research, these files are being stored on the disk, metaphorical to being stored on a docker system or FTP server. Docker is an open-source software, which allows the user to pack, provision and run virtualized application containers on an operating system. It contains dependencies needed to execute code within containers, allowing containers to move between a docker environment and OS. It uses resource isolation in the OS kernel, allowing the common operating system to be contained and run multiple times. It runs containers of docker images, which contain the dependencies needed to execute within a container but should not be mistaken for a Virtual Machine (VM), as a VM operates differently, encapsulating an entire OS, and being run through dedicated hardware resources on the machine .An FTP server is used to facilitate file transfers over the internet, FTP standing for File Transfer Protocol. Files are either uploaded to or downloaded from an FTP server. In context of this paper, containerisation allows for the data to be stored outside of the ledger, substituting the original data with container or file identifiers on the Blockchain. This allows the data to be deleted, without affecting the Blockchain’s cryptographic chain. The containerised data is protected by utilizing RSA public key encryption. This is to ensure data off the Blockchain, cannot be modified without destroying the original information or data. The encrypted data is also split up into chunks, to ensure that the data has an even lower chance of being decrypted or lost, as the Blockchain network, which is private, holds the reconstructive information for these chunks. These 3 systems, Encryption & Chunking, Blockchain Ledger and Storage Method, together allow for a Blockchain system that can continue to be used as an immutable storage method, whilst allowing the extraction of data as per a user’s request, in compliance with GDPR, specifically, Article 17

Distribution and Quantification of Antibiotic Resistant Genes and Bacteria across Agricultural and Non- Agricultural Metagenomes

There is concern that antibiotic resistance can potentially be transferred from animals to humans through the food chain. The relationship between specific antibiotic resistant bacteria and the genes they carry remains to be described. Few details are known about the ecology of antibiotic resistant genes and bacteria in food production systems, or how antibiotic resistance genes in food animals compare to antibiotic resistance genes in other ecosystems. Here we report the distribution of antibiotic resistant genes in publicly available agricultural and non-agricultural metagenomic samples and identify which bacteria are likely to be carrying those genes. Antibiotic resistance, as coded for in the genes used in this study, is a process that was associated with all natural, agricultural, and human-impacted ecosystems examined, with between 0.7 to 4.4% of all classified genes in each habitat coding for resistance to antibiotic and toxic compounds (RATC). Agricultural, human, and coastal-marine metagenomes have characteristic distributions of antibiotic resistance genes, and different bacteria that carry the genes. There is a larger percentage of the total genome associated with antibiotic resistance in gastrointestinal-associated and agricultural metagenomes compared to marine and Antarctic samples. Since antibiotic resistance genes are a natural part of both human-impacted and pristine habitats, presence of these resistance genes in any specific habitat is therefore not sufficient to indicate or determine impact of anthropogenic antibiotic use. We recommend that baseline studies and control samples be taken in order to determine natural background levels of antibiotic resistant bacteria and/or antibiotic resistance genes when investigating the impacts of veterinary use of antibiotics on human health. We raise questions regarding whether the underlying biology of each type of bacteria contributes to the likelihood of transfer via the food chain

Situational awareness and safety

This paper considers the applicability of situation awareness concepts to safety in the control of complex systems. Much of the research to date has been conducted in aviation, which has obvious safety implications. It is argued that the concepts could be extended to other safety critical domains. The paper presents three theories of situational awareness: the three-level model, the interactive sub-systems approach, and the perceptual cycle. The difference between these theories is the extent to which they emphasise process or product as indicative of situational awareness. Some data from other studies are discussed to consider the negative effects of losing situational awareness, as this has serious safety implications. Finally, the application of situational awareness to system design, and training are presented

Background Checks for Firearm Transfers, 2015 - Statistical Tables

Describes background checks for firearms transfers conducted in 2015 and presents estimates of firearm applications received and denied annually since the effective date of the Brady Act in 1994 through 2015. Statistical tables provide data on the number of firearm applications processed by the FBI and state and local agencies, number of applications denied, reasons for denial, and estimates of applications by jurisdiction and by each type of approval system. Findings are based on data from BJS's Firearm Inquiry Statistics program, which annually surveys state and local background checking agencies to collect information on firearm background check activity and combines this information with the FBI's National Instant Criminal Background Check System transaction data to generate national estimates.Highlights:Since the effective date of the Brady Act on February 28, 1994, through December 31, 2015, nearly 197 million applications for firearm transfers or permits were subject to background checks and more than 3 million applications (1.5%) were denied.Nearly 17 million applications for firearm transfers were received in 2015, up from an estimated 15 million in 2014.About 1.4% of the nearly 17 million applications for firearm transfers or permits in 2015 were denied: about 107,000 by the FBI and about 119,000 by state and local agencies.Among state agency reporters, denial rates in 2015 were 3.0% for purchase permits, 1.5% for instant checks, 1.1% for other approval checks, and 1.1% for exempt carry permits.Local agencies denied 4.2% of applications for purchase permit checks and 1.1% of applications for exempt carry permits