Gas-phase mercury in the atmosphere over the southern Baltic Sea coast

Results of atmospheric total gaseous mercury (TGM) measurements performed at two Baltic Sea coastal stations, Peninsula Hel (Poland) and Preila (Lithuania), from June 16 to August 11, 1997, are presented. High time-resolution data were obtained by using automated atomic absorption mercury vapor analyzers (Model Gardis-1A). Analysis of TGM concentration data (directional distribution, correlation with meteorological parameters, diurnal variability) detected the Baltic sea, in particular its southern part and Gulf of Gdansk, as the main gaseous mercury source for the region during the summer months. The source seemed to be activated by solar radiation, air temperature, and, probably, wind.     

Perceptions of HIV/AIDS policies and treatment programmes by Western Cape construction firms

The HIV/AIDS pandemic poses a substantial long‐term threat to economic development in South Africa. A questionnaire survey explored the perceptions of a sample of construction firms in the Western Cape regarding HIV/AIDS policy and treatment programmes. The findings show that there is no universal view about the long‐term threat of HIV/AIDS. Most organizations have awareness policies in place but prevention and treatment policies are less common. Treatment programmes are the least implemented of all intervention services due to insufficient resource capacity, the potential stigmatization of infected persons, and low take‐up rates. Despite an acknowledgement of the benefits flowing from mounting treatment programmes, doubt exists as to their financial viability.     

RECOVERING THE WIRING OF ENIGMA'S UMKEHRWALZE A

Umkehrwalze A was the original reflector used in the version of the Enigma machine employed by the German armed services. Its wiring was originally deduced by the Polish cryptanalyst Marian Rejewski in December 1932 or January 1933, but details of the wiring have not previously been published. Sufficient information to recover the wiring analytically is provided in a wartime document by Alan Turing, and other sources have been found to confirm the solution. This paper presents the wiring, along with alternative methods of recovering it from Turing's data.     

Predictive Thermal Inactivation Model for Effects and Interactions of Temperature, NaCl, Sodium Pyrophosphate, and Sodium Lactate on Listeria monocytogenes in Ground Beef

The effects and interactions of heating temperature (60 °C to 73.9 °C), salt (0.0 % to 4.5 %?w/v), sodium pyrophosphate (0.0 % to 0.5 %?w/v), and sodium lactate (0.0 % to 4.5 %?w/v) on the heat resistance of a five-strain mixture of Listeria monocytogenes in 75 % lean ground beef were examined. Meat samples in sterile filtered stomacher bags were heated in a temperature controlled waterbath to determine thermal death times. The recovery medium was tryptic soy agar supplemented with 0.6 % yeast extract and 1 % sodium pyruvate. Weibull survival functions were employed to model the primary survival curves. Then, survival curve-specific estimated parameter values obtained from the Weibull model were used for determining a secondary model. The results indicate that temperature and salt have a large impact on the inactivation kinetics of L. monocytogenes, while sodium lactate (NaL) has an impact in the presence of salt. The model presented in this paper for predicting inactivation of L. monocytogenes can be used as an aid in designing lethality treatments meant to control the presence of this pathogen in ready-to-eat products.     

A Dislocation-Based Analytical Model for the Nanoscale Processes of Shear and Plowing Friction

We describe a friction model to link the continuum-based shear and plowing method of Bowden and Tabor with the atomistic processes that occur at the nanoscale. We show that the interfacial shear component can be modeled via dislocation drag at the interface, and the plowing in terms of power-law creep. We show that without empirical friction measurements, this approach has a strong predictive power for the interfacial sliding of crystalline materials.     

Effects of phase fraction on phase morphology and triple junction configuration in anisotropic systems

It has been demonstrated that Herring’s anisotropic triple-junction equilibrium conditions do not predict a unique triple-junction configuration for junctions involving at least one anisotropic interface. In this paper, we minimize the total interfacial energy of a model two-dimensional anisotropic system to predict the preferred triple-junction configuration(s). Both the relative values of the interfacial energies and the phase fractions affect the energetics. Maps of the energetically preferred configuration(s) spanning a wide range of phase fraction and relative interfacial energies are presented. Parallel trends and key differences between the behaviors of the model anisotropic system and a (similarly configured) isotropic system are detailed. Lastly, we show how the approach used to predict equilibrium configurations (based on assumed interfacial energies) can be reversed to obtain relative interfacial energies for experimental systems where equilibrium has been reached but only geometrical parameters can be measured.     

From Part to Whole: Developing an Appreciation of Kuna Molas as Collectibles

Abstract

In the Kuna language the word mola is polysemous, with meanings which include cloth, a rectangular panel of appliquéd cloth and a complete blouse. A pair of mola panels joined together with a yoke and sleeves form a mola blouse, thus the word mola means both part and whole of an item of clothing. Sewn and worn by Kuna women and girls, molas have become identified with Panama and mola panels have become the quintessential tourist souvenir. Parallels are made between the meaning and iconic role of the Kuna mola and art forms from other indigenous cultures. Individual mola panels are found in the collections of major ethnographic, art, and textile museums and there are many private collectors in the US, Europe, Japan and Australia. The role of the mola blouse as part of the dress ensemble of Kuna women is frequently not appreciated, since complete mola blouses form a small part of many collections. The display of mola panels as artworks in ethnographic and art museum exhibitions promotes their intrinsic aesthetic qualities and contributes to distancing them from their role as a component of dress. The meaning of molas may be considered to be polyvalent: Kuna women who sew and wear molas and Kuna communities may derive various meanings; there may be various meanings attributed to specific designs; and outsiders may derive different meanings. The attraction of molas to the Western eye is explored in terms of Kuna ethnoaesthetic principles and choice of iconography, as well as aesthetic appreciation. Molas may be interpreted as early examples of craftivism and contemporary collectors are attracted to their handmade qualities.     

Contribution of NMDA and non-NMDA receptors to synaptic transmission from the brachium of the inferior colliculus to the medial subdivision of the medial geniculate nucleus in the rabbit

Previous work from this laboratory has demonstrated that monosynaptic inputs from the brachium of the inferior colliculus (BIC) to the medial subdivision of the medial geniculate nucleus (mMG) strengthen as a result of associative conditioning with an acoustic conditioned stimulus (i.e., fear conditioning). One model that has been proposed to underlie certain types of neuronal plasticity involves the recruitment of N-methyl-D-aspartic acid (NMDA)-type glutamate receptors. The purpose of the present study was to examine the relative contributions of glutamatergic NMDA and non-NMDA receptors to synaptic transmission within this pathway. Individual contributions of the specific receptor types were assessed through the use of 2-amino-5-phosphonovaleric acid (AP5), a selective NMDA receptor antagonist, and 6-cyano-5-nitroquinoxaline-2,3-dione (CNQX), a non-NMDA receptor antagonist. Bipolar stimulating electrodes were stereotaxically implanted in BIC and recording electrodes (attached to dual 32-gauge cannulae for delivery of drug) were positioned in mMG of New Zealand albino rabbits. Single pulses (150 micros, 100-350 microA) delivered to BIC resulted in short-latency (<4 ms) responses in mMG. BIC-evoked single-unit activity was recorded from mMG before, during, and at several intervals after injection of AP5, CNQX, and/or artificial cerebrospinal fluid (ACSF). Injection of either AP5 or CNQX, but not ACSF, significantly attenuated the short-latency BIC-evoked responses in the vast majority of cells tested. These findings suggest that the monosynaptic pathway from BIC to mMG is glutamatergic and that this pathway frequently employs NMDA-type receptors during electrically stimulated synaptic transmission. Due to the NMDA receptors' proposed role in plasticity (e.g., long-term potentiation), these results may have implications for understanding the mechanisms of synaptic plasticity observed at this synapse during associative learning.