Do Red Knots (Calidris Canutus Islandica) routinely skip Iceland during southward migration?

Subspecies Calidris canutus islandica of the Red Knot breeds on the arctic tundra of northeastern Canada and northern Greenland and winters along the coasts of northwestern Europe. During northward migration, it stops over in either Iceland or northern Norway. It has been assumed that it does the same during southward migration. Using ratios of stable carbon isotopes (&delta; 13 C) in whole blood, blood cells, and plasma, we investigated evidence for a stopover in Iceland en route from the breeding grounds to the Dutch Wadden Sea. With the expected diet (shellfish) and stopover duration at Iceland (12-15 days, maximum 17 days) and the turnover rates of blood cells (15.1 days) and plasma (6.0 days), Red Knots that stopped in Iceland should arrive with a blood (cell) &delta; 13 C midway between a tundra (-24.7[per thousand]) and a marine value (-14.0[per thousand]) and a plasma &delta;13 C approaching the marine value (-15.3[per thousand]). However, many adults arriving at the Wadden Sea had &delta;13 C ratios in blood (cells) and plasma below these levels, and some arrived with clear tundra signals in blood cells, suggesting that they skipped Iceland during southward migration. Surprisingly, available data suggest this also to be true for juveniles during their first southward migration. The &delta; 13 C signature of second-year birds confirmed that they oversummered in the Wadden Sea. Our findings contradict the largely untested idea that juvenile shorebirds make more stopovers than adults as well as the idea that the migration between the Nearctic and Europe is necessarily a two-leg process. <br /

Dispensing patterns of antimigraine agents with a focus on seasonal variations in prescribing

Purpose: To determine the dispensing patterns of antimigraine agents in a private healthcare setting, focusing on seasonal variations in prescribing.Methods: A retrospective, cross-sectional drug utilization study was conducted using a South African medical insurance scheme administrator database for 2016. The database contained 3 567 170 records for medicines, medical devices and procedures. All products in MIMS category 1.9 (antimigraine agents) were analysed.Results: A total of 914 antimigraine products were dispensed to 505 patients (69.70 % females) at a cost of US$10,988.63. The average age of patients was 41.57 (SD = 13.77) years. Of the eight active ingredients, clonidine was the most often dispensed (34.68 %), followed by rizatriptan (28.01 %) and ergotamine (26.04 %). Prescribing peaks were observed in February to April 2016, and again in October. These months coincide with the change in seasons to winter and to summer, respectively, in South Africa.Conclusion: The sample size was too small to make definite conclusions, but it seems that prescribing of antimigraine agents reaches a peak during seasonal change specifically autumn and spring, confirming that weather is a possible trigger factor in migraine.Keywords: Migraine, Antimigraine agents, Trigger factors, Environmental, Weather, Seasonal, Prescribing patterns, Rizatripta

Unusual patterns in 15N blood values after a diet switch in red knot shorebirds

When a diet switch results in a change in dietary isotopic values, isotope ratios of the consumer's tissues will change until a new equilibrium is reached. This change is generally best described by an exponential decay curve. Indeed, after a diet switch in captive red knot shorebirds (Calidris canutus islandica), the depletion of 13C in both blood cells and plasma followed an exponential decay curve. Surprisingly, the diet switch with a dietary 15N/14N ratio (δ15N) change from 11.4 to 8.8 ‰ had little effect on δ15N in the same tissues. The diet-plasma and diet-cellular discrimination factors of 15N with the initial diet were very low (0.5 and 0.2 ‰, respectively). δ15N in blood cells and plasma decreased linearly with increasing body mass, explaining about 40 % of the variation in δ15N. δ15N in plasma also decreased with increasing body-mass change (r 2=.07). This suggests that the unusual variation in δ15N with time after the diet switch was due to interferences with simultaneous changes in body-protein turnover.

Particle Sensor Using Solidly Mounted Resonators

This paper describes the development of a novel particle sensing system employing zinc oxide based solidly mounted resonator (SMR) devices for the detection of airborne fine particles (i.e., PM2.5 and PM10). The system operates in a dual configuration in which two SMR devices are driven by Colpitts-type oscillators in a differential mode. Particles are detected by the frequency shift caused by the mass of particles present on one resonator with while the other acts as a reference channel. Experimental validation of the system was performed inside an environmental chamber using a dust generator with the particles of known size and concentration. A sensor sensitivity of 4.6 Hz per μg/m3 was demonstrated for the SMRs resonating at a frequency of 970 MHz. Our results demonstrate that the SMR-based system has the potential to be implemented in CMOS technology as a low-cost, miniature smart particle detector for the real-time monitoring of airborne particles

Basal metabolic rate declines during long-distance migratory flight in great knots

Great Knots (Calidris tenuirostris) make one of the longest migratory flights in the avian world, flying almost 5500 km from Australia to China during northward migration. We measured basal metabolic rate (BMR) and body composition in birds before and after this flight and found that BMR decreased 42%. The mass-specific BMR based on lean mass decreased 33%. We also starved a group of pre-migratory Great Knots in captivity to determine whether they showed the same reduction in BMR without having undergone the hard work of flight. The captive birds showed a similar range and reduction of BMR values as the wild birds. Exponents of relationships between BMR and body mass in different comparisons were high, indicating large changes in BMR as a function of body mass. Analysis of the body composition of ten wild and three captive birds found that the flight muscle mass and intestine mass positively correlated with BMR

Improving Grassland Quality in Communal Arable Lands in the Eastern Cape Province, South Africa

Overgrazing and shifting cultivation practise have severely degraded communal lands in the Eastern Cape of South Africa. Methods need to be developed to improve forage quality of grazing land, especially previously cultivated lands. The aim of the study was to investigate legume species to rehabilitate arable lands abandoned from cropping, to enhance their forage quality, productivity and ecological integrity. The study was conducted in seven communities within the Eastern Cape Province. This study showed that within the communal lands studied extensive areas have been cultivated and the majority of this land is now poorly utilised. Natural grasslands ploughed for cropping did not recover its original composition and therefore lost its primary ecological condition. New improved legume cultivars can significantly enhance forage quality on cultivated lands but individual species may not have the resilience to survive nutrient poor lands and variable winter rainfall. This study shows that using a mixture of annual and perennial legume species with different life traits contributed to enhanced forage quality, especially during winter when the nutritional value of grasses was low. Because of management constraints, pasture legumes cannot be seen as stand-alone pastures, but provide a mechanism to extend the forage potential of communal grazing lands