Social inequities and food: an ecological study of the food sales of a supermarket chain

With the aim of finding out the pattern of food consumption in different socioeconomic areas of the city of Valencia and examining if the sales data from the supermarkets make up an information source which is capable of detecting inequalities and revealing trends, the sales figures of a chain of supermarkets, referring to 10 food products during 1989 and 1990 were studied. Foods were considered as "healthier" (fruit, vegetables, skimmed milk, fresh fish and chicken), "less healthy" (pork, butter and cakes) and foods indicative of a "new style of eating" (pre-cooked frozen foods and frozen food products). The ratio of between "healthier" food sales and sales of "less healthy" foods is directly related to the socio-economic level of the population. The higher the socioeconomic level, the higher, the ratio of proportions of "healthier" and less healthy" food. This pattern was similar for 1989 (2.78 in lower level districts and 3.32 in higher level districts, and in 1990 (2.92 and 4.09 respectively) (p < 0.01). From these results, we deduce the need for developing different activities for the promotion of healthy foods according to social groups.     

Remarks on food chain dynamics

The main modes of behavior of a food chain model composed of logistic prey and Holling type II predator and superpredator are discussed in this paper. The study is carried out through bifurcation analysis, alternating between a normal form approach and numerical continuation. The two-parameter bifurcation diagram of the model contains Hopf, fold, and transcritical bifurcation curves of equilibria as well as flip, fold, and transcritical bifurcation curves of limit cycles. The appearance of chaos in the model is proved to be related to a Hopf bifurcation and a degenerate homoclinic bifurcation in the prey-predator subsystem. The boundary of the chaotic region is shown to have a very peculiar structure.     

Self-diffusion in plutonium metal

We have determined self-diffusion coefficients for the epsilon, delta prime, delta, gamma, and beta phases of polycrystalline plutonium by the “thin film” tracer tech-nique, and fine sectioning. Our experiments encompassed a sample temperature range from 393 to 886 K. The corresponding diffusion times ranged from about 4 h to one year. Although our results for the epsilon phase corroborate those of others, our lattice diffu-sivity values for the delta and gamma phases differ significantly from previously reported values. Our D₀ value for delta plutonium is two-orders-of-magnitude higher than pre-viously reported and our activation energy is about 30 pct higher. However, in contrast to other studies, our measurements for the delta plutonium phase covered the entire temperature-stability range. Diffusivity values for the delta-prime phase have not previ-ously been reported. Our diffusivity measurements are reasonable, although ourD ₀ value and the activation energy derived by least squares are questionably high. We have ob-tained new values for lattice diffusivities for the gamma and beta phases. Values for the latter have not been previously reported. We interpret relatively high diffusivities re-ported earlier for the gamma phase as resulting from short-circuit path effects. The usual concentrationvs penetration curves reported here for gamma and beta phases are analyzed in terms of dislocation and other short-circuit paths. The finer sectioning technique used in this study allowed us to separate the true lattice diffusivities from the short-circuit effects found in our gamma- and beta-phase measurements. Formerly Chemist at Lawrence Livermore Laboratory     

A simple, rapid and sensitive detection of salmonella in food by polymerase chain reaction

A polymerase chain reaction (PCR) method was developed for detection of salmonella in food. A set of PCR primers was designed to amplify a 199 bp salmonella-specific DNA fragment derived from a repetitive DNA of Salmonella Weltevreden. The assay detected all 52 most prevalent serovars found in contaminated food in Thailand and no cross-reaction was observed with other non-salmonella organisms. The limit of detection was 1 fg of purified target DNA or five bacteria from pure culture. The detection of artificially contaminated food performed following a 6 h enrichment step was three bacteria per gram and the result was obtained within 4 h.     

Phase transformations in uranium,plutonium, and neptunium

The actinide metals uranium and neptunium are characterized by three allotropes, and plutonium has six solid phases with two of the allotropes having complex, low symmetry, crystal structures. Further, many phase changes in these metals are accompanied by a large specific volume change and a large enthalpy change. Phase transformations in uranium and plutonium have been studied extensively but very little experimental work has been conducted to understand the phase transformations in neptunium. The low temperature transformations occur isothermally and exhibit simple TTT curves similar to many alloys. The kinetics in the metals are controlled more by purity and thermal history than by any inherent feature of the metals. Mechanisms in the pure metals are inadequately understood, and the crystal-lographic relations are complex. The β → α transformations in uranium and plutonium are diffusional near the α β equilibrium temperature, and they are both reminiscent of shear transformations at low temperatures. Skip transformations have been studied in these metals and the role of grain size on transformation behavior has been investigated more than in other metals. Accordingly, the roles of metal purity, thermal history, microstructure, mechanical properties, and thermodynamic variables are discussed, particularly as they might be related to phase transformations in other systems. Generalities have been difficult to establish for plutonium and uranium alloys. Among well-known metals the zirconium and titanium transformations form the closest analogs to the uranium transformations, but there is no obvious analog to the plutonium transformations. Formerly with the Argonne National Laboratory, Argonne, Ill. 60439, This paper is based on a presentation made at a symposium on “Phase Transformations in Less Common Metals: A Dialogue,” held at the Fall Meeting in Cleveland on October 16, 1972, under the sponsorship of the Phase Transformations Activity, Materials Science Division, American Society for Metals.     

Phase stability and phase transformations in plutonium and plutonium-gallium alloys

The complexity of phase stability and transformations in plutonium alloys is reflected in the plutonium-gallium (Pu-Ga) phase diagram, which is perhaps the most complex of all binary systems. Although many investigations have explored phase equilibria, transformation systematics, and structure/property relations in the Pu-Ga system, many outstanding problems remain and new issues regularly appear. In this article, we describe recent dilatometry and calorimetry measurements on pure plutonium and plutonium-gallium alloys. We also present recent phase diagram modeling that attempts to unravel differences between the U.S. and Russian Pu-Ga phase diagrams. The ultimate goal of this work is to produce the first internally consistent database of thermophysical properties of this system so that a true equilibrium phase diagram can be produced and so that stability can be predicted over a range of conditions. This article is based on a presentation in the symposium “Terence E. Mitchell Symposium on the Magic of Materials: Structures and Properties” from the TMS Annual Meeting in San Diego, CA in March 2003.     

Use of polymerase chain reaction and restriction enzyme analysis to directly detect and identify Salmonella typhimurium in food

Magnetic resonance (MR) microscopy was used to noninvasively investigate the development of live rat embryos in utero. The difficulty in making sequential observations of a developing mammalian embryo has frustrated developmental biologists for many years. Most current technologies analyze normal and abnormal development by observing end point phenotypes (in fixed specimens) rather than investigating the live embryo. MR microscopy was adapted to allow rat litters to be scanned three times each (at 1- to 3-day intervals) and has produced images of live developing embryos. It was demonstrated that repeated anesthesia and imaging protocols produced no gross malformations in the rat pups that were subsequently delivered and observed. Three-dimensional projection encoding with phase rewinders produced isotropic [256(3)] image data sets in about 30 minutes with excellent tissue contrast arising from steady-state effects in the amniotic fluid.     

Protection of the Croatian population from accidental radioactive contamination of the food chain

A reversed-phase high-performance liquid chromatographic (HPLC) assay is described for the quantitative determination of lometrexol in biological samples; the assay is rapid, simple, specific, and highly sensitive. The method requires the dissociation of lometrexol from folate-binding proteins present in blood and formation of a fluorescent oxidized derivative of the compound. The dissociation of lometrexol from folate-binding proteins was achieved by acidification to pH 3.5 using ammonium formate, followed by serum protein precipitation with perchloric acid. The protein-free lometrexol was subsequently oxidized by MnO2 at 90 degrees C for 10 min. Chromatographic separation of lometrexol without interference was achieved on a C18 reversed-phase column with a convex gradient, using acetonitrile-0.1% ammonium formate, pH 7.0, as the mobile phase. In human serum and urine the calibration curve was linear between 5 and 300 nM. The lower limit of quantification was 5 nM. The method has been applied successfully to measure serum and urinary levels of lometrexol in patients.     

Spatial and temporal variation of phenanthrene-degrading bacteria in intertidal sediments

Phenanthrene-degrading bacteria were isolated from a 1-m2 intertidal sediment site in Boston Harbor. Samples were taken six times over 2 years. A total of 432 bacteria were isolated and characterized by biochemical testing. When clustered on the basis of phenotypic characteristics, the isolates could be separated into 68 groups at a similarity level of approximately 70%. Several groups (a total of 200 isolates) corresponded to well-characterized species belonging the genera Vibrio and Pseudomonas. Only 51 of the 437 isolates (< 11.7% of the total) hybridized to a DNA probe that encodes the upper pathway of naphthalene and phenanthrene degradation in Pseudomonas putida NCIB 9816. A cluster analysis indicated that the species composition of the phenanthrene-degrading community changed significantly from sampling date to sampling date. At one sampling time, 12 6-mm-diameter core subsamples were taken within the 1-m2 site to determine the spatial variability of the degrading communities. An analysis of molecular variance, performed with the phenotypic characteristics, indicated that only 6% of the variation occurred among the 12 subsamples, suggesting that the subsamples were almost identical in composition. We concluded that the communities of phenanthrene-degrading bacteria in the sediments are very diverse, that the community structure undergoes significant change with time but does not vary significantly on a spatial scale of centimeters, and that the predominant genes that encode phenanthrene degradation in the communities are not well-characterized.     

Innervated liver plays an inhibitory role in regulation of food intake

BACKGROUND: With the onset of eating, the associated rise of dopamine in the lateral hypothalamus (LHA-DA) is thought to regulate quantity of food consumed per meal. Early release of LHA-DA induced by eating is facilitated by oronasal stimulation; we propose that the subsequent LHA-DA response induced by nutrients in the portal vein is dampened by the innervated liver. This was tested by measuring LHA-DA in normal rats: during parenteral feeding to bypass oronasal stimulation, while eating during parenteral feeding, and while eating only. METHODS: Rats had either total liver denervation or sham operation, with placement of a jugular vein catheter and LHA-DA microdialysis cannula. After a 3-week recovery period total liver denervated rats were randomized to parenterally fed, food only, and parenteral plus food groups each with sham-operated controls in which LHA-DA was measured. RESULTS: No difference in LHA-DA release in food only groups occurred between total liver denervated or sham-operated rats. A significantly higher rise in LHA-DA was observed in total liver denervated versus sham-operated rats in parenterally fed (129% +/- 4% versus 116% +/- 2%; p < 0.05) and parenteral plus food (151% +/- 4% versus 134% +/- 4%; p < 0.05) groups. CONCLUSIONS: In total liver denervation versus sham operation, an increase in LHA-DA release occurs during parenteral feeding and eating during parenteral feeding, suggesting that innervated liver inhibits LHA-DA release.     

The evaluation of a fluorogenic polymerase chain reaction assay for the detection of Salmonella species in food commodities

This article provides an overview of a new theory of suggested involuntariness in hypnosis, developed in conjunction with Irving Kirsch. The theory is based on the following ideas. First, high hypnotizable participants enter hypnosis with a conscious intention to feel and behave in line with suggested experiences and movements. Second, people who are easily hypnotized hold firm expectations that they will succeed in following the suggestions of the hypnotist. Third, the intention and expectation in turn function as response sets in the sense that they trigger the hypnotic response automatically. Fourth, given the intention to feel and behave in line with the hypnotist's suggestions, hypnotized individuals show no hesitation to experience the suggested movements as involuntary because (a) these movements are actually triggered automatically, and (b) the intention to cooperate with the hypnotist as well as the expectation to be able to do so create a heightened readiness to experience these actions as involuntary.     

Engineered assembly of intertwined oligomers of an immunoglobulin chain

Domain 1 of CD2 (CD2.D1) forms a conventional Ig fold stabilised by non-covalent antiparallel contacts between beta-strands. Removing two residues from the middle of the protein sequence, where the polypeptide chain normally folds back upon itself, stabilises an open conformation. In this modified molecule, the optimum evolved contacts between side-chains can only be satisfied through the antiparallel association of two chains to create a symmetrical pair of pseudo-domains. Here, we describe the dynamics of the switch between monomeric and dimeric states and demonstrate the extension of this novel underlying principle to trimer and tetramer formation. The ability of a protein molecule to form higher-order antiparallel structures is reminiscent of the behaviour of hairpins, duplexes, three-way and Holliday junctions in DNA.