A biomarker of n−3 compliance in patients taking fish oil for rheumatoid arthritis

Dietary fish oil supplements have been shown to have benefits in rheumatoid arthritis (RA), other inflammatory diseases, and in cardiovascular disease. As with any medical advice, variability will exist with regard to adherence and consequent biochemical or pharmacophysiologic effects. The aim was to explore the utility of plasma phospholipid EPA as a measure of n−3 PUFA intake and response to standardized therapeutic advice given in an outpatient or office practice setting, to increase dietary n−3 PUFA, including a fish oil supplement. Patients with early RA were given verbal and written advice to alter their dietary n−3 PUFA intake, including ingestion of 20 mL of bottled fish oil on juice daily. The advice included instructions to increase n−3 PUFA and to avoid foods rich in n−6 PUFA. Every 3 mon, blood samples were obtained for analysis of plasma phospholipid FA. Plasma phospholipid EPA was used as the primary index of n−3 PUFA intake. A diverse response was seen, with about one-third of patients achieving a substantial elevation of plasma phospholipid EPA over the 12-mon study period. A third had little change, with the remainder achieving intermediate levels. Data obtained longitudinally from individual patients indicated that substantial elevations of EPA (>5% total plasma phospholipid FA) could be maintained for more than 3 yr. Plasma phospholipid EPA is a convenient measure of adherence to advice to take a dietary n−3 PUFA-rich fish oil supplement. This measure may prove a useful adjunct to intention to treat analyses in determining the effect of dietary fish oil supplements on long-term outcomes in arthritis and other chronic inflammatory diseases. It may also provide a guide to the effectiveness of therapeutic and preventive messages designed to increase n−3 PUFA intake.     

Simple substitution distance and metamorphic detection

To evade signature-based detection, metamorphic viruses transform their code before each new infection. Software similarity measures are a potentially useful means of detecting such malware. We can compare a given file to a known sample of metamorphic malware and compute their similarity—if they are sufficiently similar, we classify the file as malware of the same family. In this paper, we analyze an opcode-based software similarity measure inspired by simple substitution cipher cryptanalysis. We show that the technique provides a useful means of classifying metamorphic malware.     

Quantum relaxation of magnetisation in magnetic particles

At temperatures below the magnetic anisotropy energy, monodomain magnetic systems (small particles, nanomagnetic devices, etc.) must relax quantum mechanically-thermal activation is ineffective. The discrete nature of the spectrum is important. This quantum relaxation must be mediated by the coupling to both nuclear spins and phonons (and electrons if either particle or substrate is conducting).We analyze the effect of each of these couplings, and then combine them to get results for the physical relaxation of magnetic particles at low temperature and bias. This done for both conducting and insulating systems. The effect of electrons and phonons can be handled using oscillator bath representations; but the effect of environmental spins must be described using a spin bath representation of the environment, the theory of which was developed in previous papers.Conducting systems can be modelled by a giant Kondo Hamiltonian, with nuclear spins added in as well. At low temperatures, even microscopic particles on a conducting substrate will have their magnetisation frozen over millenia by a combination of electronic dissipation and the degeneracyblocking caused by nuclear spins. Raising the temperature leads to a sudden unblocking of the spin dynamics at a well defined temperature. We analyze in turn the 3 different cases of (a) conducting substrate, conducting particle (b) conducting substrate, insulating particle, and (c) conducting particle, insulating substrate.Insulating systems are quite different. The relaxation is strongly enhanced by the coupling to nuclear spins. At short times the magnetization of an ensemble of particles relaxes logarithmically in time, after an initial very fast decay-this relaxation proceeds entirely via the nuclear spins. At longer times phonons take over, but the decay rate is still governed by the temperature-dependent nuclear bias field acting on the particles-decay may be exponential or power-law depending on the temperature. Depending on the parameters of the particles and the environment, the crossover from nuclear spin-mediated to phonon-mediated relaxation can take place after a time ranging between fractions of a second up to months.The most surprising feature of the results is the pivotal role played by the nuclear spins. The results apply to any experiments on magnetic particles in which interparticle interactions are unimportant (we do not deal with the effect of interparticle interactions in this paper). They are also relevant to future magnetic device technology.     

Hunting for metamorphic engines

In this paper, we analyze several metamorphic virus generators. We define a similarity index and use it to precisely quantify the degree of metamorphism that each generator produces. Then we present a detector based on hidden Markov models and we consider a simpler detection method based on our similarity index. Both of these techniques detect all of the metamorphic viruses in our test set with extremely high accuracy. In addition, we show that popular commercial virus scanners do not detect the highly metamorphic virus variants in our test set.A talk based on the results in this paper was presented by the authors at Defcon 14, August 5, 2006, Las Vegas, Nevada.     

Studies of 1s2s 3S-1s2p 3P transitions in helium-like Ne8+ recoil ions using photographic spectroscopy

This work describes the application of the technique of photographic VUV spectroscopy to accurate measurement of the wavelength of the theoretically interesting 1s2s ³S₁-1s2p ³P₂ transition in helium-like Ne⁸⁺ in a recoil ion source. Good resolution is obtained, and a preliminary value of 124.815±0.002 nm is found for the wavelength.     

Distance and the presentation of visual stimuli to birds

Hemodynamic factors have profound influences on blood vessels. To test the hypothesis that hemodynamic conditions modify the pattern of remodeling in response to injury, monocrotaline (MCT) injury in Sprague-Dawley rats was followed 1 week later by left pneumonectomy to increase blood flow to the right lung. Right pulmonary artery remodeling in these MCT plus pneumonectomy animals was compared with animals receiving MCT or pneumonectomy alone. Neointimal changes developed in more than 90% of all right lung intra-acinar vessels 5 weeks after MCT injury (4 weeks after pneumonectomy). Neointimal lesions did not develop in untreated animals or in animals receiving MCT or pneumonectomy only. Animals with a neointimal pattern of remodeling developed severe right ventricular hypertrophy (RVH) whereas animals with a medial hypertrophy pattern of remodeling (MCT only) developed moderate RVH compared with control animals. Neointimal lesions and RVH were similar whether injury preceded pneumonectomy or vice versa. To exclude the possibility that neointimal lesions resulted from injury plus post-pneumonectomy compensatory lung growth, rather than injury plus increased flow, a left subclavian-pulmonary artery anastomosis was substituted for pneumonectomy. Neointimal lesions and severe RVH developed in these animals but were not seen in animals receiving either MCT or anastomosis only. These studies demonstrate an important role for hemodynamics in determining the pattern of pulmonary vascular remodeling after injury.     

Predator discrimination error and the benefits of Müllerian mimicry

Müllerian mimicry has traditionally been thought to benefit both unpalatable mimic and model species but recently its existence has been questioned. Even if both mimic and model species are unpalatable, they are unlikely to be equally unpalatable. It has been argued that the more unpalatable species will suffer a cost of increased predation because the presence of the more palatable mimic will increase its perceived palatability (by the predator), similar to that experienced by a model in Batesian mimicry. Yet, previous models of Müllerian mimicry have assumed that a predator can discriminate perfectly between available prey. We argue that this is not the case and that discrimination error is an important factor in determining the nature of mimetic relationships. Using computer simulations we show that the nature of a mimetic relationship will depend on the trade-off between the cost of an increase in perceived palatability and the benefits of a reduction in predator discrimination error. We show that mimicry can be unequivocally Müllerian, with both species benefiting, and propose that palatability should no longer be used as the sole defining characteristic of a mimetic relationship. Copyright 1998 The Association for the Study of Animal Behaviour. Copyright 1998 The Association for the Study of Animal Behaviour.     

Relativistic energy contributions to the N = 2 triplet levels in helium-like ions

The 1s2s³S?1s2p³P_J (J = 0, 1, 2) transitions in helium-like ions can be used to test QED, but only if the other contributions to the transition energy, and especially the relativistic contributions are known to high accuracy.This work tests the relativistic calculations by comparing the theoretical ${}^3\text{P}{}_{\mathrm{J}}$ splittings (which are nearly ndependent of QED) with each other and with experiment. An estimate of the largest uncalculated relativistic term, of relative order α⁴Z⁴, is also made.It is found that the calculations of Hata and Grant are not very accurate, and that the small discrepancy between Drake and experiment vanishes if the α⁴Z⁴ relativistic term is included.     

Multifamily malware models

When training a machine learning model, there is likely to be a tradeoff between accuracy and the diversity of the dataset. Previous research has shown that if we train a model to detect one specific malware family, we generally obtain stronger results as compared to a case where we train a single model on multiple diverse families. However, during the detection phase, it would be more efficient to have a single model that can reliably detect multiple families, rather than having to score each sample against multiple models. In this research, we conduct experiments based on byte n-gram features to quantify the relationship between the generality of the training dataset and the accuracy of the corresponding machine learning models, all within the context of the malware detection problem. We find that neighborhood-based algorithms generalize surprisingly well, far outperforming the other machine learning techniques considered.