Prolonging Shelf-Life of Carp by Combined Ionising Radiation and Refrigeration

Experiments were performed using ionisating radiation in order to prolong the shelf-life of two groups of refrigerated fish ( Cyprinus carpio ). After irradiation fish were kept at 0–2°C. Non-irradiated fish reached the non-acceptability point in 16 days and irradiated fish reached that point in 31 days. No difference was found between shelf-life of whole or eviscerated fish. If fish were immediately cooled to 0°C after death, their shelf-life was prolonged considerably. From this study it is clear that chemical tests of freshness such as TVB-N and K value determination are not appropriate for the study of irradiated fish. Organoleptic estimations and a new determination using an odour concentration meter seem to fit best the objective determination of freshness.     

Relationships between probabilistic Boolean networks and dynamic Bayesian networks as models of gene regulatory networks

A significant amount of attention has recently been focused on modeling of gene regulatory networks. Two frequently used large-scale modeling frameworks are Bayesian networks (BNs) and Boolean networks, the latter one being a special case of its recent stochastic extension, probabilistic Boolean networks (PBNs). PBN is a promising model class that generalizes the standard rule-based interactions of Boolean networks into the stochastic setting. Dynamic Bayesian networks (DBNs) is a general and versatile model class that is able to represent complex temporal stochastic processes and has also been proposed as a model for gene regulatory systems. In this paper, we concentrate on these two model classes and demonstrate that PBNs and a certain subclass of DBNs can represent the same joint probability distribution over their common variables. The major benefit of introducing the relationships between the models is that it opens up the possibility of applying the standard tools of DBNs to PBNs and vice versa. Hence, the standard learning tools of DBNs can be applied in the context of PBNs, and the inference methods give a natural way of handling the missing values in PBNs which are often present in gene expression measurements. Conversely, the tools for controlling the stationary behavior of the networks, tools for projecting networks onto sub-networks, and efficient learning schemes can be used for DBNs. In other words, the introduced relationships between the models extend the collection of analysis tools for both model classes.     

Output feedback stabilizability and passivity in nonstationary and nonlinear systems

Passivity properties and passivity conditions have been shown to be very important for the stability of various methodologies of control with uncertainty in linear‐time‐invariant (LTI) systems. Many publications have defined the conditions that allow LTI systems to become strictly passive (and their transfer function strictly positive real) via constant or dynamic output feedback. As beyond the usual uncertainty, real‐world systems are not necessarily invariant, this paper expands the applicability of previous results to nonstationary and nonlinear systems. The paper first reviews a few pole–zero dynamics definitions in nonstationary systems and relates them to stability and passivity of the systems. The paper then finds the sufficient conditions that allow nonstationary systems to become stable and strictly passive via static or dynamic output feedback. Applications in robotics and adaptive control are also presented. Copyright © 2009 John Wiley & Sons, Ltd.     

Care and cleanliness of the environment in public places: a survey of Kibbutzim in Israel

It is argued that the problems of environmental pollution, and those of the inadequacy of formal social control mechanisms in contemporary societies are the unintended dysfunctional consequences of two separate but interrelated clusters of change processes. Consequently, solutions to the former require a thorough study of the latter in their relation to behaviour of individuals vis a vis the physical environment in public places.

A survey of all 332 kibbutzim in Israel, conducted in 1973, assessed the level of “active care” (i.e. landscaping, lawns, trees, etc.) and “cleanliness” (i.e. absence of litter, refuse, etc.) found in eleven different locations in each kibbutz. Although kibbutzim are generally considered rural settlements, the data showed a typically urban reliance on “the authorities” to take care of the appearance of public places. Further analysis indicated that at least three variables are systematically related to this normative pattern: residential instability, age of settlement, and population size. Other background variables considered and analyzed were not found to be statistically related to active care and cleanliness.     

Elevated burnout predicts the onset of musculoskeletal pain among apparently healthy employees.

Musculoskeletal (MS) pain is highly prevalent in the working population, often resulting in chronic disability. Burnout represents accumulated exposure to work-related stresses and therefore could predict the incidence of MS pain. We investigated prospectively the extent to which changes in the levels of burnout over time predict new cases of MS pain. Participants were 1,704 apparently healthy employed men and women who underwent periodic health examination at three points of time (T1, T2, and T3), over a period of about three years. We used the T1 to T2 changes in the levels of burnout, depressive symptoms, and anxiety to predict the onset of new cases of MS pain between T2 and T3, while controlling for possible confounders. Logistic regression results indicated that the T1–T2 change in burnout levels was associated with a 2.09-fold increased risk of MS pain (95% confidence interval = 1.07–4.10). No support was found for the possibility of reverse causation; that is, that MS pain predicts subsequent elevations of burnout levels. It was concluded that burnout might be a risk factor in the development of MS pain in apparently healthy individuals. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Responses of freshwater prawn,Macrobrachium rosenbergii,to chemical attractants

Chemoreception in the adults of the freshwater prawnMacrobrachium rosenbergii was investigated under controlled laboratory conditions, using behavioral assays. Tests were carried out on groups, as well as on individuals, all at their intermolt stages of the molt cycle, and prestarved for three to four days. Of 28 different substances tested, the amino acids taurine, glycine, arginine, and betaine, as well as trimethylamine, elicited a positive behavioral response in at least 50% of the test animals when applied at a threshold concentration of 10^–5-10^–8 M. A positive response comprises enhanced antennular flicking and food search motion. Of the various nucleotides tested for chemoattraction, only adenosine monophosphate elicited a response similar to that of the above amino acids, although at a concentration of 10^–4 M, whereas adenosine diphosphate required a dosage of 10^–1 M.     

Nitriding of AISI M2 tool steel in an inductive r.f. plasma

The nitriding of AISI M2 tool steel in an inductive r.f. plasma was investigated. The plasma was sustained with a 27.12 MHz generator in gas mixtures of N₂ and H₂ at a pressure of 10 mbar. The ion nitriding was performed at a net r.f. power of 400 W at substrate temperatures of 450–500 °C. X-ray diffraction studies of the treated samples revealed that the most efficient formation of nitride phases was observed in samples nitrided in a pure N₂ plasma. As a result of the ion nitriding the surface hardness was substantially increased from a Vickers hardness VHN of 290 kgf mm^-2 for untreated samples to a maximum VHN of 1200 kgf mm^-2 for samples treated in a plasma sustained in a gas mixture with N₂:H₂ = 1:1.     

Characterization of titanium coatings obtained by the cold plasma technique

Titanium coatings obtained by the RF cold plasma technique at a temperature of 550°C were characterized in order to create a model mechanism for the formation process. Scanning Electron Microscopy (SEM), X-ray diffraction, Transmission Electron Microscopy (TEM), Energy Dispersive Analysis of X-ray (EDAX) and Auger Electron Spectroscopy (AES) were employed to identify and to characterize the sputtered films. The coatings obtained were composed of titanium-copper intermetallic compounds. It is suggested that the intermetallic compounds are formed in a solid state reaction due to local energetic processes taking place in the plasma, in spite of the relatively low temperature of the substrate. According to the suggested model copper migrates outwards from the substrate, in an enhanced synergistic process, along the surfaces of the titanium deposited particles.