Aproximative solutions to the neutrino oscillation problem in matter

We present approximative solutions to the neutrino evolution equation calculated by different methods. In a two neutrino framework, using the physical parameters which gives the main effects to neutrino oscillations from nu{e} to another flavors for L=3000Km and E=1GeV, the results for the transition probability calculated by using series solutions, by to take the neutrino evolution operator as a product of ordered partial operators and by numerical methods, for a linearly and sinusoidally varying matter density are compared. The extension to an arbitrary density profile is discussed and the evolution operator as a product of partial operators in the three neutrino case is obtained.Comment: 12 pages, 5 figure

ANCHOR: logically-centralized security for Software-Defined Networks

While the centralization of SDN brought advantages such as a faster pace of innovation, it also disrupted some of the natural defenses of traditional architectures against different threats. The literature on SDN has mostly been concerned with the functional side, despite some specific works concerning non-functional properties like 'security' or 'dependability'. Though addressing the latter in an ad-hoc, piecemeal way, may work, it will most likely lead to efficiency and effectiveness problems. We claim that the enforcement of non-functional properties as a pillar of SDN robustness calls for a systemic approach. As a general concept, we propose ANCHOR, a subsystem architecture that promotes the logical centralization of non-functional properties. To show the effectiveness of the concept, we focus on 'security' in this paper: we identify the current security gaps in SDNs and we populate the architecture middleware with the appropriate security mechanisms, in a global and consistent manner. Essential security mechanisms provided by anchor include reliable entropy and resilient pseudo-random generators, and protocols for secure registration and association of SDN devices. We claim and justify in the paper that centralizing such mechanisms is key for their effectiveness, by allowing us to: define and enforce global policies for those properties; reduce the complexity of controllers and forwarding devices; ensure higher levels of robustness for critical services; foster interoperability of the non-functional property enforcement mechanisms; and promote the security and resilience of the architecture itself. We discuss design and implementation aspects, and we prove and evaluate our algorithms and mechanisms, including the formalisation of the main protocols and the verification of their core security properties using the Tamarin prover.Comment: 42 pages, 4 figures, 3 tables, 5 algorithms, 139 reference

Service satisfaction and behavioural intention in the cell phone network service provider industry – a comparisson between customers of different cell phone network service providers

Abstract: South Africa’s cell phone network service providers have gained a reputation of providing inadequate levels of service. The study relayed in this article aims to uncover the customers’ level of satisfaction with their cell phone network service providers, and how this satisfaction influences their behavioural intention in the South African context. This will enable cell phone network service providers to understand the relationship between satisfaction and behavioural intention, which in turn will contribute to developing customer satisfaction and retention strategies, as well as long-term customer loyalty. A total of 500 usable questionnaires were retained for data analysis. The study has uncovered a statistically significant difference between Vodacom and MTN customers with regard to their overall service satisfaction and overall behavioural intention, and this resulted in a partial acceptance of the hypotheses. The results of the study further reveal that customers of different cell phone network service providers feel positive towards their service provider and about doing business with them, but do not believe the interaction is the best outcome that can be achieved. The results also reveal that customers intend to continue using their cell phone network service provider in the future, but are not willing to recommend them to other people. Cell phone network service providers should therefore make adjustments to improve their customer service, quality and strategies to retain customers and increase customer satisfaction

Benchmarking some Portuguese S&T system research units: 2nd Edition

The increasing use of productivity and impact metrics for evaluation and comparison, not only of individual researchers but also of institutions, universities and even countries, has prompted the development of bibliometrics. Currently, metrics are becoming widely accepted as an easy and balanced way to assist the peer review and evaluation of scientists and/or research units, provided they have adequate precision and recall. This paper presents a benchmarking study of a selected list of representative Portuguese research units, based on a fairly complete set of parameters: bibliometric parameters, number of competitive projects and number of PhDs produced. The study aimed at collecting productivity and impact data from the selected research units in comparable conditions i.e., using objective metrics based on public information, retrievable on-line and/or from official sources and thus verifiable and repeatable. The study has thus focused on the activity of the 2003-06 period, where such data was available from the latest official evaluation. The main advantage of our study was the application of automatic tools, achieving relevant results at a reduced cost. Moreover, the results over the selected units suggest that this kind of analyses will be very useful to benchmark scientific productivity and impact, and assist peer review.Comment: 26 pages, 20 figures F. Couto, D. Faria, B. Tavares, P. Gon\c{c}alves, and P. Verissimo, Benchmarking some portuguese S\&T system research units: 2nd edition, DI/FCUL TR 13-03, Department of Informatics, University of Lisbon, February 201

Comparison of fungal contamination between hospitals and companies food units

A descriptive study was developed to compare air and surfaces fungal contamination in ten hospitals’ food units and two food units from companies. Fifty air samples of 250 litres through impaction method were collected from hospitals’ food units and 41 swab samples from surfaces were also collected, using a 10 by 10 cm square stencil. Regarding the two companies, ten air samples and eight surface samples were collected. Air and surface samples were collected in food storage facilities, kitchen, food plating and canteen. Outdoor air was also collected since this is the place regarded as a reference. Simultaneously, temperature, relative humidity and meal numbers were registered. Concerning air from hospitals’ food units, 32 fungal species were identified, being the two most commonly isolated genera Penicillium sp

Air fungal contamination in ten hospitals’ food units from Lisbon

A descriptive study was developed to monitor air fungal contamination in ten food units from hospitals. Fifty air samples of 250 litres were collected through impaction method. Samples were collected in food storage facilities, kitchen, food plating, canteen and also, outside premises, since this is the place regarded as reference. Simultaneously, environmental parameters were also monitored, including temperature and relative humidity through the equipment Babouc, LSI Sistems and according to the International Standard ISO 7726

Population genomics and phylogeography of a benthic coastal shark (Scyliorhinus canicula) using 2b-RAD single nucleotide polymorphisms

The existence of strong genetic structure is expected in species with limited ability to disperse and philopatric behaviour. These life-history traits are found in many small benthic elasmobranchs, such as in the small-spotted catshark (Scyliorhinus canicula). However, no evidence of genetic structure was found across its northeastern Atlantic (NEA) range using traditional molecular markers. Here, fine-scale genetic differentiation was detected between the British Isles and southern Iberia using 2674 single nucleotide polymorphism loci generated using 2b-restriction site-associated DNA (2b-RAD). Geographical distance and historical demography were two major drivers shaping the distribution of genetic diversity of S. canicula along the NEA. Significant positive spatial autocorrelation of allelic frequencies was detected, with genetic differentiation generally increasing with geographical distance. However, marked genetic divergence of the Celtic Sea and South Portugal collections from their closest neighbours resulted in geographically constrained genetic breaks south of the British Isles and off southwestern Iberia. Historical demographic reconstruction of population pairs across these genetic breaks suggested a scenario of historical isolation before secondary contact, probably related to distinct northern and southern glacial refugia. These results provide new insights into the population structure of S. canicula along the NEA and serve as a reference for benthic elasmobranchs with similar distribution ranges