Automated two-dimensional separation flow system with electrochemical preconcentration, stripping, capillary electrophoresis and contactless conductivity detection for trace metal ion analysis

This paper describes the automation of a fully electrochemical system for preconcentration, cleanup, separation and detection, comprising the hyphenation of a thin layer electrochemical flow cell with CE coupled with contactless conductivity detection (CE-C(4)D). Traces of heavy metal ions were extracted from the pulsed-flowing sample and accumulated on a glassy carbon working electrode by electroreduction for some minutes. Anodic stripping of the accumulated metals was synchronized with hydrodynamic injection into the capillary. The effect of the angle of the slant polished tip of the CE capillary and its orientation against the working electrode in the electrochemical preconcentration (EPC) flow cell and of the accumulation time were studied, aiming at maximum CE-C(4)D signal enhancement. After 6 min of EPC, enhancement factors close to 50 times were obtained for thallium, lead, cadmium and copper ions, and about 16 for zinc ions. Limits of detection below 25 nmol/L were estimated for all target analytes but zinc. A second separation dimension was added to the CE separation capabilities by staircase scanning of the potentiostatic deposition and/or stripping potentials of metal ions, as implemented with the EPC-CE-C(4)D flow system. A matrix exchange between the deposition and stripping steps, highly valuable for sample cleanup, can be straightforwardly programmed with the multi-pumping flow management system. The automated simultaneous determination of the traces of five accumulable heavy metals together with four non-accumulated alkaline and alkaline earth metals in a single run was demonstrated, to highlight the potentiality of the system.

Mice lacking angiotensin-converting enzyme have increased energy expenditure, with reduced fat mass and improved glucose clearance

In addition to its role in the storage of fat, adipose tissue acts as an endocrine organ, and it contains a functional renin-angiotensin system (RAS). Angiotensin-converting enzyme (ACE) plays a key role in the RAS by converting angiotensin I to the bioactive peptide angiotensin II (Ang II). In the present study, the effect of targeting the RAS in body energy homeostasis and glucose tolerance was determined in homozygous mice in which the gene for ACE had been deleted (ACE^-/-) and compared with wild-type littermates. Compared with wild-type littermates, ACE^-/- mice had lower body weight and a lower proportion of body fat, especially in the abdomen. ACE^-/- mice had greater fed-state total energy expenditure (TEE) and resting energy expenditure (REE) than wild-type littermates. There were pronounced increases in gene expression of enzymes related to lipolysis and fatty acid oxidation (lipoprotein lipase, carnitine palmitoyl transferase, long-chain acetyl CoA dehydrogenase) in the liver of ACE^-/- mice and also lower plasma leptin. In contrast, no differences were detected in daily food intake, activity, fed-state plasma lipids, or proportion of fat excrete in fecal matter. In conclusion, the reduction in ACE activity is associated with a decreased accumulation of body fat, especially in abdominal fat depots. The decreased body fat in ACE^-/- mice is independent of food intake and appears to be due to a high energy expenditure related to increased metabolism of fatty acids in the liver, with the additional effect of increased glucose tolerance.

An examination of taxpayers' attitutes towards the Australian Tax System : findings from a survey of tax scheme investors

In recent years, the number of taxpayers involved in aggressive tax planning has more than doubled, posing a serious threat to the integrity of Australia's tax system. To deal with the problem, the Australian Taxation Office (ATO) implemented a number of initiatives aimed at combating aggressive tax planning. Part of the ATO's crackdown involved issuing amended assessments to the 42,000 Australians who invested in mass marketed tax schemes. The majority of investors, however, resisted the ATO's attempts to recover scheme related tax debts. This paper discusses the findings of an empirical study that shows that the resistance was due partly to the manner in which the ATO dealt with the schemes issue. Using survey data collected from 2301 tax scheme investors, and 2040 taxpayers from the general population, it will be shown that those who invested in tax schemes are more disillusioned with the tax system, are more hostile and resistant toward the ATO, and are more likely to resent paying tax as a result.

Bathymetry and frontal system interactions influence seasonal foraging movements of lactating subantarctic fur seals from Marion Island

Sixteen lactating subantarctic fur seals Arctocephalus tropicalis were satellite-tracked during the winter of 2006 (n = 6), summer of 2006/07 (n = 6) and autumn/winter (n = 4) of 2007, from Marion Island, Southern Ocean. Despite varied individual movement patterns, a favoured foraging area lay to the northeast of the island. In contrast to findings for populations at similar latitudes, seals from Marion Island did not undertake short overnight foraging trips, but trips consistently went beyond 300 km from the island. This aligns with the at-sea duration of lactating seals’ foraging trips from temperate Amsterdam Island, but differs from subantarctic Crozet and Macquarie islands. Time spent at sea, maximum distances travelled and movement variation of tracks from the island varied seasonally. Faecal analysis suggests the diet comprised primarily myctophid fish with limited seasonal variation. Well-defined areas of restricted movement coincided with significant bathymetric features to the west/northwest of the Crozet Plateau, with the Del Caño Rise clearly being important. Positive and negative sea-surface height anomalies (compared to the mean) appeared to be preferred by most seals across seasons. Higher summer sea-surface temperatures correlated with the movements of some seals. Higher chlorophyll a concentrations dictated transit and foraging areas during summer. Bathymetrically influenced oceanographic variables likely explain these preferred long-distance eastward movements. The Îles Crozet and Marion island subantarctic fur seals differ in their foraging ecology despite being neighbours. Conversely, the subantarctic fur seal populations from the distant Amsterdam and Marion islands appear to be similarly influenced by such environmental factors.

Reducing energy consumption of vehicle air conditioning system by an energy management system

This paper presents an energy management system to reduce the energy consumption of a vehicle when its air conditioning system is in use. The system controls the mass flow rate of the air by dynamically adjusting the blower speed and air-gates opening under various heat and loads circumstances. Simulations were conducted for a travelling vehicle operating the air conditioning system without and with the developed energy management system. The results show that the comfort temperature within the cabin room is achieved for reduced amount of energy consumption.

Many routes lead to Rome : potential causes for the multi-route migration system of Red Knots, Calidris canutus islandica

Migrants, such as birds or representatives of other taxa, usually make use of several stopover sites to cover the distance between their site of origin and destination. Potentially, multiple routes exist, but often little is known about the causes and consequences of alternative migration routes. Apart from their geographical distribution, the suitability of potential sites might play an important role in the animals’ decisions for a particular itinerary. We used an optimal-migration model to test three nonmutually exclusive hypotheses leading to variations in the spring migration routes of a subspecies of Red Knot, Calidris canutus islandica, which migrates from wintering grounds in Western Europe to breeding grounds in Greenland and the Canadian Arctic: the breeding location hypothesis, the energy budget hypothesis, and the predation risk hypothesis. Varying only breeding location, the model predicted that birds breeding in the Canadian Arctic and on West Greenland stop over on Iceland, whereas birds breeding in East and Northeast Greenland migrate via northern Norway, a prediction that is supported by empirical findings. Energy budgets on stopover sites had a strong influence on the choice of route and staging times. Varying foraging-intensity and mass-dependent predation risk prompted the birds to use less risky sites, if possible. The effect of simultaneous changes in the energy budget and predation risk strongly depended on the site where these occurred. Our findings provide potential explanations for the observations that C. canutus islandica uses a diverse array of migration routes. Scrutinizing the three alternative driving forces for the choice of migratory routes awaits further, specific data collection in rapidly developing fields of research (e.g., predation risk assessment, GPS tracking). Generally, the type of modeling presented here may not only highlight alternative explanations, but also direct follow-up empirical research.

Mass production of nanofibers from a spiral coil

In this study, we have demonstrated that a rotating metal wire coil can be used as a nozzle to electrospin nanofibers on a large-scale. Without using any needles, the rotating wire coil, partially immersed in a polymer solution reservoir, can pick up a thin layer of charged polymer solution and generate a large number of nanofibers from the wire surface simultaneously. This arrangement significantly increases the nanofiber productivity. The fiber productivity was found to be determined by the coil dimensions, applied voltage and polymer concentration. The dependency of fiber diameter on the polymer concentration showed a similar trend to that for a conventional electrospinning system using a syringe needle nozzle, but the coil electrospun fibers were thinner with narrower diameter distribution. The profiles of electric field strength in the coil electrospinning was calculated and showed concentrated electric field intensity on the top wire surface.

Applications of a TransFLash in an embedded system debugging

In this paper, the hardware and software design for using a TF card in debugging an embedded system are described. The used hardware platform is designed based on a PXA310 application processor. The Android open source operating system is used as the software platform. The design of the connection circuit between the application processor and the TF card is introduced first. Secondly, the design of the TF card driver program and the method for Android system to mount the TF card are described. In designing the TF driver program, an SPI operation mode and FAT32 file system are used. The transplant of the FAT32 file system is presented more detail. Finally, the paper introduced the system debugging and the test results are given for the TF card used in a video data acquisition unit of a video monitoring. It is shown that high speed data exchange and good universal property can be obtained by using a TF card to download a system image during developing and debugging. The TF card used in debugging can be used as a mass storage in the embedded product without the need of changing the design for debugging the system and it is also convenient for a user to upgrade operating system.

In hot pursuit : fluctuating mating system and sexual selection in sand lizards

A changing climate is expected to have profound effects on many aspects of ectotherm biology. We report on a decade-long study of free-ranging sand lizards (Lacerta agilis), exposed to an increasing mean mating season temperature and with known operational sex ratios. We assessed year-to-year variation in sexual selection on body size and postcopulatory sperm competition and cryptic female choice. Higher temperature was not linked to strength of sexual selection on body mass, but operational sex ratio (more males) did increase the strength of sexual selection on body size. Elevated temperature increased mating rate and number of sires per clutch with positive effects on offspring fitness. In years when the “quality” of a female's partners was more variable (in standard errors of a male sexual ornament), clutches showed less multiple paternity. This agrees with prior laboratory trials in which females exercised stronger cryptic female choice when male quality varied more. An increased number of sires contributing to within-clutch paternity decreased the risk of having malformed offspring. Ultimately, such variation may contribute to highly dynamic and shifting selection mosaics in the wild, with potential implications for the evolutionary ecology of mating systems and population responses to rapidly changing environmental conditions.

Fathers with highly demanding partners and offspring in a semidesert environment: energetic aspects of the breeding system of Monteiro's Hornbills (Tockus monteiri) in Namibia

Molting females of Monteiro's Hornbills (Tockus monteiri) seal themselves in nest cavities to breed until chicks are about half grown. To gain insight into the chronology of energy requirements of the Monteiro's Hornbill family unit in relation to this peculiar breeding strategy, we measured a number of ecological, physiological, and environmental variables during the Monteiro's Hornbill's breeding season. Those measurements included rates of energy expenditure of female Monteiro's Hornbills while in the nest cavity, characterizing their thermal environment, timing of egg laying, molt, hatching and fledging of chicks, as well as measuring clutch size and chick growth. Temperatures within the nest box varied between 12 and 39°C and did not affect the female energy expenditure. Female body mass and energy expenditure averaged 319 g and 5 W, respectively, at the start of concealment and decreased by on average 1.1 g day -1 and 0.05 W day -1 during at least the first 30 days of the 52-58 day concealment period. Clutch size varied between 1 and 8 and averaged 4.1 eggs, with eggs averaging only 66% of the mass predicted for a bird of this size. Over the range of chick ages at which the female might leave the nest, the predicted energy requirements for maintenance and tissue growth for a Monteiro's Hornbill chick increase sharply from 1.2 W at age 8 to 3.0 W at age 25. Reduction of the female energy requirement with time, the relatively low growth rate and therewith low energy requirements of Monteiro's Hornbill chicks, and an appropriate timing of the female's exodus from the nest cavity all aid in containing peak energy demands to levels that are sustainable for the food provisioning male.

In-depth search focused on furans, lactones, volatile phenols, and acetals as potential age markers of Madeira wines by comprehensive two-dimensional gas chromatography with time-of-flight mass spectrometry combined with solid phase microextraction

The establishment of potential age markers of Madeira wine is of paramount significance as it may contribute to detect frauds and to ensure the authenticity of wine. Considering the chemical groups of furans, lactones, volatile phenols, and acetals, 103 volatile compounds were tentatively identified; among these, 71 have been reported for the first time in Madeira wines. The chemical groups that could be used as potential age markers were predominantly acetals, namely, diethoxymethane, 1,1-diethoxyethane, 1,1-diethoxy-2-methyl-propane, 1-(1-ethoxyethoxy)-pentane, trans-dioxane and 2-propyl-1,3-dioxolane, and from the other chemical groups, 5-methylfurfural and cis-oak-lactone, independently of the variety and the type of wine. GC × GC-ToFMS system offers a more useful approach to identify these compounds compared to previous studies using GC−qMS, due to the orthogonal systems, that reduce coelution, increase peak capacity and mass selectivity, contributing to the establishment of new potential Madeira wine age markers. Remarkable results were also obtained in terms of compound identification based on the organized structure of the peaks of structurally related compounds in the GC × GC peak apex plots. This information represents a valuable approach for future studies, as the ordered-structure principle can considerably help the establishment of the composition of samples. This new approach provides data that can be extended to determine age markers of other types of wines.

Production technology for entomopathogenic fungus using a biphasic culture system

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Operational parameters of soybean seeding in santa fe system

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Root system of Panicum maximum Jacq. cv. IPR-86 Mil(e)over-capnio fertilized with nitrogen and submitted to rotational stocking

The effect of nitrogen on the root system of the species Panicum maximum Jacq. cv. IPR-86 Mil (e) over cap nio, under grazing, was evaluated. The N rates were 0; 150; 300 and 450 kg/ha. year. The root density was evaluated during pregrazing at five years of successive N application, in three depths (0-10; 10-20 and 20-40 cm) and the root growth at 7, 14, 21, and 35 days after grazing. The grazing method adopted was rotational stocking. Root length and root mass densities in pre-and post-grazing presented maximum values at rates 204, 206, 192, and 197 kg/ha of N, respectively. The root growth (in root length density) increased, on average, until 29 days after grazing at rates 0, 150, and 300 kg/ha; at 450 kg/ha N rate, the increase was linear. Independently of N rates, around 60 and 25% of IPR-86 Mil (e) over cap nio cultivar root system was concentrated in 0-10 and 10-20 cm depth, respectively.

Gastro-intestinal transit time in South American deer

The study of diet and physiological peculiarities of the digestive system of neotropical deer is not well known and the literature shows inconsistencies. To better understand the digestive system of these mammals the difference in the gastro-intestinal transit time of four species of neotropical deer (Mazama americana, Mazama gouazoubira, Mazama nana, Blastocerus dichotomus), kept ill captivity, was evaluated. Four plants (Neonotonia wightii, Morus albans, Medicago sativa, Leucaena leucocephala) were utilized and two variables were measured, mean time of the beginning of the elimination (BE) and mean time of permanence (TP). The results obtained for BE indicated similarity among the deer species, with significant differences between M. gouazoubira (mean = 13.62 hr) and M. Americana (mean = 19.25 hr). For the plants, the BE was faster with N. wightii and L. leucocephala, and slower for M. sativa. The TP results for B. dichotomus showed longer time when compared to the other species, whereas M. gouazoubira had a lower permanence. Overall, N. wightii had the highest retention time in the digestive tract of all the deer species studied. Associated with this observation, N. wightii had the highest quantity of plant fiber of the plants tested. In a similar fashion M. sativa showed the lowest TP in the digestive tract of the deer and had the lowest quantity of acid detergent fiber. The data from this study showed that, within species, the shape of the excretion curve of the plants was similar when the animals consumed N. wightii or M. sativa. Blastocerus dichotomus and M. gouazoubira had the highest and the lowest gastro-intestinal transit time, respectively. This suggests that these species characterize different abilities to digest high fiber food, and consequently, represent the two extremities in the morphophysiological adaptation within the deer species evaluated. This information is vital because it is important to know the digestive physiology to define the diet of captive animals, particularly regarding the quantity and quality of fiber. Zoo Biol 25:47-57, 2006. (C) 2005 Wiley-Liss, Inc.