Two-dimensional projections of an hypercube

We present a method to project a hypercube of arbitrary dimension on the plane, in such a way as to preserve, as well as possible, the distribution of distances between vertices. The method relies on a Montecarlo optimization procedure that minimizes the squared difference between distances in the plane and in the hypercube, appropriately weighted. The plane projections provide a convenient way of visualization for dynamical processes taking place on the hypercube.Comment: 4 pages, 3 figures, Revtex

Using intelligent optimization methods to improve the group method of data handling in time series prediction

In this paper we show how the performance of the basic algorithm of the Group Method of Data Handling (GMDH) can be improved using Genetic Algorithms (GA) and Particle Swarm Optimization (PSO). The new improved GMDH is then used to predict currency exchange rates: the US Dollar to the Euros. The performance of the hybrid GMDHs are compared with that of the conventional GMDH. Two performance measures, the root mean squared error and the mean absolute percentage errors show that the hybrid GMDH algorithm gives more accurate predictions than the conventional GMDH algorithm

The Influence of Growth Stage on Carcass Compositionand Factors Associated with Marbling Development in Beef Cattle

There are many cellular regulatory factors that ultimately determine the intramuscular fat, or marbling content and quality of beef carcasses. Identifying factors which play a critical role in the development of intramuscular fat throughout the feeding period and determining how cattle feeders can manipulate these factors will be crucial to continue improving beef quality. Ideally, marbling must increase without excess accumulation of adipose in depots that are undesirable and economically detrimental (subcutaneous and visceral). The results of this study are novel as they show not only what cellular factors play a role in marbling development, but also how their expression and presence change as an animal grows in an American‐style production system. The increase in both expression and presence of peroxisome proliferator‐activated receptor γ (PPARγ) at the end of the feeding phase suggest the proliferation and differentiation of additional cells to adipocytes is required in order to increase intramuscular fat content. This does not mean that adipocyte filling (lipogenesis) does not play a key role as well. However marbling content will reach a plateau without the recruitment of additional adipocytes. While it has been previously established that intramuscular adipocytes have a pattern of metabolism unique to other adipocytes, further research into how the metabolism of intramuscular fat differs from other fat depots and how this metabolism changes throughout the feeding phase will enhance the ability to produce high quality carcasses while limiting undesirable carcass fat

Magnetic ordering of Mn sublattice, dense Kondo lattice behavior of Ce in (RPd3)8Mn (R = La, Ce)

We have synthesized two new interstitial compounds (RPd3)8Mn (R = La and Ce). The Mn ions present in "dilute" concentration of just 3 molar percent form a sublattice with an unusually large Mn-Mn near neighbor distance of ~ 85 nm. While the existence of (RPd3)8M (where M is a p-block element) is already documented in the literature, the present work reports for the first time the formation of this phase with M being a 3d element. In (LaPd3)8Mn, the Mn sub-lattice orders antiferromagnetically as inferred from the peaks in low-field magnetization at 48 K and 23 K. The latter peak progressively shifts towards lower temperatures in increasing magnetic field and disappears below 1.8 K in a field of ~ 8 kOe. On the other hand in (CePd3)8Mn the Mn sublattice undergoes a ferromagnetic transition around 35 K. The Ce ions form a dense Kondo-lattice and are in a paramagnetic state at least down to 1.5 K. A strongly correlated electronic ground state arising from Kondo effect is inferred from the large extrapolated value of C/T = 275 mJ/Ce-mol K^2 at T = 0 K. In contrast, the interstitial alloys RPd3Mnx (x = 0.03 and 0.06), also synthesized for the first time, have a spin glass ground state due to the random distribution of the Mn ions over the available "1b" sites in the parent RPd3 crystal lattice.Comment: 18 figures and 20 pages of text documen

Control of an atom laser using feedback

A generalised method of using feedback to control Bose-Einstein condensates is introduced. The condensates are modelled by the Gross-Pitaevskii equation, so only semiclassical fluctations can be suppressed, and back-action from the measurement is ignored. We show that for any available control, a feedback scheme can be found to reduce the energy while the appropriate moment is still dynamic. We demonstrate these schemes by considering a condensate trapped in a harmonic potential that can be modulated in strength and position. The formalism of our feedback scheme also allows the inclusion of certain types of non-linear controls. If the non-linear interaction between the atoms can be controlled via a Feshbach resonance, we show that the feedback process can operate with a much higher efficiency.Comment: 6 pages, 7 figure

Young women and limits to the normalisation of condom use: a qualitative study

Encouraging condom use among young women is a major focus of HIV/STI prevention efforts but the degree to which they see themselves as being at risk limits their use of the method. In this paper, we examine the extent to which condom use has become normalised among young women. In-depth interviews were conducted with 20 year old women from eastern Scotland (N = 20). Purposive sampling was used to select a heterogeneous group with different levels of sexual experience and from different social backgrounds. All of the interviewees had used (male) condoms but only three reported consistent use. The rest had changed to other methods, most often the pill, though they typically went back to using condoms occasionally. Condoms were talked about as the most readily available contraceptive method, and were most often the first contraceptive method used. The young women had ingrained expectations of use, but for most, these norms centred only on their new or casual partners, with whom not using condoms was thought to be irresponsible. Many reported negative experiences with condoms, and condom dislike and failure were common, lessening trust in the method. Although the sexually transmitted infection (STI) prevention provided by condoms was important, this was seen as additional, and secondary, to pregnancy prevention. As the perceived risks of STIs lessened in relationships with boyfriends, so did condom use. The promotion of condoms for STI prevention alone fails to consider the wider influences of partners and young women's negative experiences of the method. Focusing on the development of condom negotiation skills alone will not address these issues. Interventions to counter dislike, method failure, and the limits of the normalisation of condom use should be included in STI prevention efforts

Bi-Objective Community Detection (BOCD) in Networks using Genetic Algorithm

A lot of research effort has been put into community detection from all corners of academic interest such as physics, mathematics and computer science. In this paper I have proposed a Bi-Objective Genetic Algorithm for community detection which maximizes modularity and community score. Then the results obtained for both benchmark and real life data sets are compared with other algorithms using the modularity and MNI performance metrics. The results show that the BOCD algorithm is capable of successfully detecting community structure in both real life and synthetic datasets, as well as improving upon the performance of previous techniques.Comment: 11 pages, 3 Figures, 3 Tables. arXiv admin note: substantial text overlap with arXiv:0906.061

United classification of cosmic gamma-ray bursts and their counterparts

United classification of gamma-ray bursts and their counterparts is established on the basis of measured characteristics: photon energy E and emission duration T. The founded interrelation between the mentioned characteristics of events consists in that, as the energy increases, the duration decreases (and vice versa). The given interrelation reflects the nature of the phenomenon and forms the E-T diagram, which represents a natural classification of all observed events in the energy range from 10E9 to 10E-6 eV and in the corresponding interval of durations from about 10E-2 up to 10E8 s. The proposed classification results in the consequences, which are principal for the theory and practical study of the phenomenon.Comment: Keywords Gamma rays: burst