Mode coupling contribution to radiation losses in curvatures for high and low numerical aperture plastic optical fibers

We have studied the optical power losses due to multiple curvatures in polymethylmetacrylate (PMMA) plastic optical fibers (POFs) of different numerical apertures (NAs) and attenuation. The fibers were tested for several configurations in order to assess the influence of different types of curved-to-straight fiber transitions in the amount of power radiation. We found that losses are below the standards for all tested fiber types, and thus, they are a suitable choice for local area network (LAN) applications. In addition, our results revealed the presence of modal interactions as confirmed using an experimental procedure to estimate the mode coupling strength for the same fibers.     

Effects of worker size on the dynamics of fire ant tunnel construction

Social insects work together to complete tasks. However, different individuals within a colony may vary in task proficiency. We investigated if fire ant (Solenopsis invicta) worker body size influenced the ability to construct tunnels—a key component of subterranean nests. We monitored excavation by worker groups in a substrate of small wetted glass particles in quasi-two-dimensional arenas. Morphological and network features of the tunnel system were measured. Total tunnel area did not differ significantly between groups of large and small workers, although the tunnel area of control sized workers was significantly larger than that of large workers. Moreover, large workers created wider but shorter tunnels, with slower growth rate of tunnel number. However, edge–vertex scaling and degree distribution of the tunnel network were similar across all treatments. In all cases, the amount of excavated material was correlated with the number of active workers. Our study reveals that morphological features of excavated tunnels show modest variation when constructed by workers of varying sizes, but topological features associated with the tunnel network are conserved. These results suggest that important behavioural aspects of tunnel construction—and thus nest building—are similar among morphologically distinct members of fire ant societies.     

The place of public space in the lives of Middle Eastern women migrants in Australia

For Middle Eastern migrants to Australia, the process of acculturation is compounded by Islamophobia, which is on the rise, with many incidents occurring in public spaces and targeting women. Through in-depth interviews, this paper examines how women migrants from the Middle East, especially Muslim ones, are affected. The study finds that Middle Eastern women migrants have a different perspective on public space compared to local populations, and this difference stems from their cultural, political and religious backgrounds. These findings can help cities create inclusive and culturally-sensitive public spaces, which catalyze a ‘sense of belonging’ and ‘sense of place’ among migrants.     

Effect of vacuum ageing on quality changes of lamb steaks from early fattening lambs during aerobic display

The effects of vacuum ageing on the quality changes of lamb steaks during retail display were assessed. Biceps femoris and Quadriceps femoris muscles from thirty early fattening lambs fed barley straw and concentrate or alfalfa and concentrate were used. Half of the muscles were vacuum aged for three weeks (VA), and the other half were not aged (control). Control and VA muscles were sliced and aerobically displayed. Weight loss, pH, aldehyde contents, instrumental color characteristics and color acceptance were measured at display days 1, 3, 7 and 14. At day 1 redness was higher in VA lamb. However, redness of VA lamb decreases more rapidly during further storage. Redness and color acceptance decreased in VA lamb from day 3, whereas in not-aged lamb the decrease was observed from day 7 onwards. From days 7 to 14 a drop of color acceptance accompanied by an increase in pH and a decrease in lightness was observed in control and VA lamb.     

On the Use of Static Temperature Measurements as Process Variation Observable

In this paper we present the use of static temperature measurements as process variation observable. Contrary to previously published thermal testing methods, the proposed methodology does not need an excitation signal, thus reducing test cost and improving built-in capabilities of thermal monitoring. The feasibility of the technique and a complete test methodology is presented using a narrowband LNA as example. Finally, a complete electro-thermal co-simulation test bench between the LNA and a differential temperature sensor embedded in the same silicon die is presented in order to validate the results. Results prove that RF figures of merit can be extracted from DC temperature measurements done without loading or exciting the RF circuit under test.     

CO<Subscript>2</Subscript> adsorption at high pressures in MCM-41 and derived alkali-containing samples: the role of the textural properties and chemical affinity

The adsorption properties of N₂ and CO₂ of MCM-41 and derived alkali-containing samples were analyzed over a wide range of pressures (up to ~4500 kPa) and temperatures (between 30 and 300 °C). The high-pressure and high-temperature experiments were carried out on pure MCM-41 and K- and Na-impregnated derived samples. It was analyzed the influence of pressure and temperature on the CO₂ capture capacity on pure and impregnated samples. The adsorption performance was correlated to the structure and textural properties of the materials using X-ray diffraction and N₂ adsorption–desorption measurements. The addition of an alkaline element changes the textural properties of the material increasing the pore size, which positively affected the CO₂ adsorption capacity of these materials at high pressure. In addition, the isosteric heats of adsorption gave information about the chemical affinity between the impregnated materials and CO₂. The CO₂ adsorption at ~ 4500 kPa for the samples with 5 wt% Na at 100 and 200 °C were 77.98 and 9.79 mmol g^?1, respectively, while the pure MCM-41 adsorbs only 8.92 mmol g^?1.     

Changes in ochratoxin A and type B trichothecenes contained in wheat flour during dough fermentation and bread-baking

Ochratoxin A (OTA) and type B trichothecenes are mycotoxins that occur frequently in cereals and thus can be found in cereal by-products such as bread. The aim of this work was to study the variation of the levels of OTA, deoxynivalenol (DON), 3-acetyldeoxynivalenol (3-ADON) and nivalenol (NIV) during the bread-making process. This was done by using wheat flour spiked with different levels of toxins. Mycotoxin levels were controlled after fermentation of the dough with yeasts (Saccharomyces cerevisiae) and after further baking at different temperature–time combinations. Analysis of variance (ANOVA) of the results showed a significant reduction in OTA level (p < 0.05) during fermentation of the dough. The reduction ranged between 29.8% and 33.5%, depending on the initial concentration of toxin in the flour. During this period, the level of the other mycotoxins studied was not modified. By contrast, in the baking phase there were significant changes in the levels of the four mycotoxins, although the reduction was similar under all the baking conditions. Considering all the temperature–time conditions tested, it can be concluded that during the baking period the average reduction of OTA, NIV, 3-ADON, and DON was 32.9%, 76.9%, 65.6%, and 47.9%, respectively.     

Chronic exposure of rats to hypoxic environment alters the mechanism of energy transfer in myocardium

We have investigated the effect of chronic exposure of rats to an hypoxic environment (10% O2; 3 weeks), on the first step of the intracellular energy transfer process in the myocardium, i.e. the transfer at mitochondrial level of high energy bonds from ATP to creatine. In the left ventricles from rats adapted to normobaric hypoxia, we observed, using the permeabilized fiber technique, that the stimulatory effect of creatine on the mitochondrial respiration in presence of a low ADP concentration (0.1 mM) was attenuated when compared to control. Furthermore, the creatine-induced decrease of the apparent K(m) for ADP of the mitochondrial respiration, which is observed in control, was significantly reduced. Both the basal and maximal respiratory rates of the fibers were unchanged by the hypoxic exposure of the rats. A significant decrease of the total creatine kinase activity from 755 to 630 IU/g wet weight (for control and hypoxic rats, respectively) was detected and was accompanied by a 25% decrease in mitochondrial isoform activity (mitoCK) and in the mitoCK/citrate synthase ratio. In the right ventricles, identical alterations in the effect of creatine on apparent K(m) for ADP were observed while we did not detect any changes in CK activity. The decrease in mitoCK activity and the fall in the reactivity of respiration to creatine could be interpreted as a mechanism for downregulating oxygen demand during chronic hypoxia. The consequences of such alterations on energy metabolism of cardiomyocytes under conditions of reduced oxygen supply are discussed.     

A microcontroller-based portable electrocardiograph recorder

We describe a low cost portable Holter design that can be implemented with off-the-shelf components. The recorder is battery powered and includes a graphical display and keyboard. The recorder is capable of acquiring up to 48 hours of continuous electrocardiogram data at a sample rate of up to 250 Hz.