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Mass Changes (mass + change)
Kinds of Mass Changes Selected AbstractsAltered Expression of SOCS3 in the Hypothalamic Arcuate Nucleus during Seasonal Body Mass Changes in the Field Vole, Microtus agrestisJOURNAL OF NEUROENDOCRINOLOGY, Issue 2 2007E. Król We have previously shown that cold-acclimated (8 °C) male field voles (Microtus agrestis) transferred from short day (SD, 8 h light) to long day (LD, 16 h light) photoperiod exhibit an increase in body mass lasting 4 weeks, after which they stabilise at a new plateau approximately 7.5 g (24.8%) higher than animals maintained in SD. By infusing voles with exogenous leptin, we have also demonstrated that SD voles respond to the hormone by reducing body mass and food intake, whereas LD animals increasing body mass are resistant to leptin treatment. In the present study, we investigated whether seasonal changes in body mass could be linked to modulation of the leptin signal by suppressor of cytokine signalling-3 (SOCS3). We used in situ hybridisation to examine hypothalamic arcuate nucleus (ARC) expression of SOCS3, neuropeptide Y (NPY), agouti-related peptide (AgRP), pro-opiomelanocortin (POMC) and cocaine- and amphetamine-regulated transcript (CART) genes in 90 voles exposed to either SD or LD for up to 11 weeks. LD voles increasing body mass had significantly higher levels of SOCS3 mRNA than SD or LD voles with a stable body mass. There were no associated changes in expression of NPY, AgRP, POMC and CART genes. These results suggest that voles that regulate body mass at either the lower (SD) or upper (LD) plateau remain sensitive to leptin action, whereas SOCS3-mediated leptin resistance is a short-term mechanism that enables animals to move between the stable body mass plateaus. Our data provide evidence that expression of SOCS3 in the ARC is involved in the modulation of the strength of the leptin signal to facilitate seasonal cycles in body mass and adiposity. [source] Body mass change strategies in blackbirds Turdus merula: the starvation,predation risk trade-offJOURNAL OF ANIMAL ECOLOGY, Issue 2 2005R. MACLEOD Summary 1It is theoretically well established that body mass in birds is the consequence of a trade-off between starvation risk and predation risk. There are, however, no studies of mass variation from sufficiently large wild populations to model in detail the range of diurnal and seasonal mass change patterns in natural populations and how these are linked to the complex environmental and biological variables that may affect the trade-off. 2This study used data on 17 000 individual blackbirds Turdus merula to model how mass changes diurnally and seasonally over the whole year and over a wide geographical area. Mass change was modelled in respect of temperature, rainfall, day length, geographical location, time of day and time of year and the results show how these mass changes vary with individual size, age and sex. 3The hypothesis that seasonal mass is optimized over the year and changes in line with predictors of foraging uncertainty was tested. As theory predicts, reduced day length and reduced temperature result in increased mass and the expected seasonal peak of mass in midwinter. 4The hypothesis that diurnal mass gain is optimized in terms of starvation,predation risk trade-off theory was also tested. The results provide the first empirical evidence for intraspecies seasonal changes in diurnal mass gain patterns. These changes are consistent with shifts in the relative importance of starvation risk and predation risk and with the theory of mass-dependent predation risk. 5In winter most mass was gained in the morning, consistent with reducing starvation risk. In contrast, during the August,November non-breeding period a bimodal pattern of mass gain, with increases just after dawn and before dusk, was adopted and the majority of mass gain occurred at the end of the day consistent with reducing mass-dependent predation risk. The bimodal diurnal mass gain pattern described here is the first evidence that bird species in the wild gain mass in this theoretically predicted pattern. [source] Starling foraging success in relation to agricultural land-useECOGRAPHY, Issue 3 2002Ola Olsson Changes in agricultural land-use have been suggested to contribute to the decline of several bird species through negative effects on their food supply during breeding. One important change in land-use has been loss of pastures, especially permanent pastures. In this study we investigated how different forms of agricultural land-use affected foraging success of a declining bird species, the European starling Sturnus vulgaris. We let caged starlings forage in different forms of agricultural fields and determined time spent foraging and foraging success. The starlings' activity level (time spent actively foraging) as well as the number of prey caught per time unit was strongly related to the abundance of prey in soil samples. Also the body mass change during the experiment was positively related to activity level and prey capture rate. We found consistent differences in foraging variables between habitats. In spring sown grain starlings were least active and found fewer prey items at a lower rate than in any other habitat. The other three habitats differed less, but in general mowed hay fields appeared slightly more valuable than the cultivated and natural pastures. We did not find any differences between natural and cultivated pastures in foraging variables. Thus, starling foraging success is higher in grass-covered fields than in cultivated fields, but the management of the grass-covered fields mattered less. The results are consistent with starlings having higher population densities and breeding success in areas with higher availability of pasture. We suggest that the physical structure of the habitat (sward height) and moisture may be additional variables that need to be taken into account to explain starling breeding density and success in the agricultural landscape. [source] Food preferences and the value of animal food for the carabid beetle Amara similata (Gyll.) (Col., Carabidae)JOURNAL OF APPLIED ENTOMOLOGY, Issue 9-10 2005S. Fawki Abstract:, Several studies have shown that the mainly granivorous carabid beetles, e.g. Amara spp., include animal food in their diet to a considerable extent. We therefore hypothesized that the performance of these beetles would be enhanced by dietary mixing including both seeds and animal food. In order to test this, we conducted laboratory feeding experiments with adults and larvae of Amara similata. Both adults and larvae were subjected to different diet treatments including: seeds, houseflies, grasshoppers, earthworms, slugs and snails in pure and mixed diets. Larval survival, development time, pupal and teneral weights were used as indicators of food quality for the larvae. For the adult beetles, mass change was used as an indicator of food quality. We found seeds to be high-quality food, while all pure animal diets were of low quality for both adults and larvae. Animal foods added to the seed diet had both positive and negative effects. A mixed diet of all foods enhanced the mass gain of adults compared with the seed diet, but reduced larval performance dramatically. Earthworms and grasshoppers added to seeds increased the pupal and teneral weights, while reduced larval survival. Thus, A. similata is omnivorous with a mainly granivorous feeding habit. It may gain benefits on some fitness parameters and incur costs on others from preying or scavenging on animal food. Therefore, the overall fitness consequences of a mixed seed-animal diet are uncertain. [source] The Antarctic palaeo record and its role in improving predictions of future Antarctic Ice Sheet change,JOURNAL OF QUATERNARY SCIENCE, Issue 1 2010Michael J. Bentley Abstract This paper reviews the ways in which the palaeo record of Antarctic Ice Sheet change can be used to improve understanding of contemporary ice sheet behaviour, and thus enhance predictions of future sea-level change. The main areas where the palaeo ice sheet record can contribute are understanding long-term ice sheet trajectory; providing data against which ice sheet models can be tested; to identify and understand the range and types of natural ice sheet behaviour; to balance the global water budget; to correct contemporary glaciological measurements of mass change; and to understand the relationship between polar ecosystems and the ice sheet. I review each in turn and argue that research priorities include understanding past West Antarctic Ice Sheet collapse and its timing; a focus on the palaeo record of rapid retreat events and how these unfolded in the geological past; improving the number and range of ice sheet reconstructions, particularly through the Holocene; continuing to investigate the potential for using sediments and landforms to parameterise basal conditions in ice sheet models; and understanding past East Antarctic Ice Sheet dynamics, particularly the evidence for partial deglaciation. Copyright © 2009 John Wiley & Sons, Ltd. [source] Synthesis and Fourier transform Raman spectroscopic study of diene-terminated polystyrene oligomersJOURNAL OF RAMAN SPECTROSCOPY, Issue 3 2005N. J. Ward Abstract Polystyrene oligomers capped with a known number of butadiene or isoprene units were synthesized by ,living' anionic polymerization in cyclohexane. The FT-Raman spectra of these compounds show small but significant differences in ,(CC) wavenumber position depending on whether just a single unit or several units of the diene are present at the chain end. However, if the butadiene experiments are repeated under polar-modified conditions, so that 1,2- rather than 1,4-addition takes place, the ,(CC) Raman band position is found to be independent of the number of ,out-of-chain' vinyl double bonds which are present. This conclusion is explained in terms of the mass change on diene addition to the polymer chains. Application of the method for the quantitation of polymer chain-end diene termination is proposed. Copyright © 2004 John Wiley & Sons, Ltd. [source] Determination of the Oxygen Deficiency in Vacuum-Hot-Pressed Ferroelectric Ceramics Using a Thermogravimetric TechniqueJOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 2 2000Qi Tan An attempt to measure the oxygen deficiency in vacuum-hot-pressed ferroelectric target materials was made, using a thermogravimetric method. The approach was intended to measure the relative mass increase of oxygen-deficient sheet samples, with respect to an oxidized reference that was annealed in air. A saturation of mass change was achieved, which indicated a saturated oxidation state and provided a basis for further calculation of the oxygen deficiency in the samples. Results were obtained for barium strontium titanate and lead lanthanum zirconate titanate compositions, which shows the feasibility of applying the thermogravimetric method to ferroelectric materials. [source] Metal dusting resistance of high chromium alloysMATERIALS AND CORROSION/WERKSTOFFE UND KORROSION, Issue 11 2003H. J. Grabke Metal dusting; hoch Chromhaltige Legierungen; Chromoxidschicht; Aufkohlung Abstract Samples of 5 high Cr-alloys were discontinuously exposed for 10,000 hours under severe metal dusting conditions, i. e. in flowing 49%CO-49%H2 -2%H2O at 650°C. After each of the 11 exposure periods the mass change was determined and any coke removed and weighed. Metallographic cross sections were prepared after about 4,000 h and 10,000 h. The high Cr-alloys: 1. PM 2000 (Fe-19%Cr-5.5%Al-0.5%Ti-0.5%Y2O3), 2. Cr-44%Fe-5%Al-0.4%Ti-0.5%Y2O3, 3. Cr-50%Ni, 4. Cr-5%Fe-1%Y2O3 and 5. porous chromium showed no or only minute metal dusting attack. Compared to the attack on reference samples of Alloy 601 (Ni-23%Cr-14%Fe-1.4%Al), the metal dusting symptoms were negligible on the 5 high Cr-alloys, minor coking and pitting and no internal carburization was observed. Because of the high Cr-content, carbon solution and ingress should be minute, and in addition are inhibited by the formation of a chromia scale, as confirmed for four of the Cr-rich alloys, and formation of an alumina scale on PM 2000. These alloys could be used for parts exposed to severe metal dusting conditions, and in fact, 50Cr-50Ni has been applied successfully under such conditions. [source] Correlates of body mass evolution in primatesAMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY, Issue 3 2006Christophe Soligo Abstract Body mass is undoubtedly central to the overall adaptive profile of any organism. Despite this, very little is known of what forces drive evolutionary changes in body mass and, consequently, shape patterns of body mass distribution exhibited by animal radiations. The search for factors that may influence evolutionary processes in general frequently focuses on environmental parameters such as climate change or interspecific competition. With respect to body mass, there is also the suggestion that evolutionary lineages may follow an inherent trend toward increased body mass, known as Cope's rule. The present paper investigates whether overall directional trends of body mass change, or correlations between patterns of body mass evolution and environmental factors have influenced the evolution of body mass in plesiadapiforms and primates. Analyses of the global fossil record of plesiadapiforms and primates suggest that the former did indeed follow an overall trend toward increased body mass compatible with the predictions of Cope's rule. In contrast, neither primates as a whole, nor a number of individual primate radiations (Adapiformes, Omomyiformes, and Anthropoidea), show any indication of overall directional patterns of body mass change. No correlations of primate body mass change with either the latitudinal distribution of fossil species, or with estimates of global temperature trends, were found. There is evidence, however, that direct competition between omomyiforms and adapiforms (the two main primate radiations known from the Paleogene) influenced processes of body mass evolution in omomyiforms. Am J Phys Anthropol, 2006. © 2006 Wiley-Liss, Inc. [source] A Study of Gypsum Scale Formation using Quartz Crystal MicrobalanceASIA-PACIFIC JOURNAL OF CHEMICAL ENGINEERING, Issue 1-2 2006T. A. Hoang The quartz crystal microbalance (QCM) has been used extensively as a mass sensor due to its extremely high sensitivity to small mass loadings. Conventional measurement of the amount of scale deposited on a surface is restricted by the sensitivity limit of analytical balances. Thefirst attempt to investigate the deposition of gypsum scale on a surface using a rotating electrochemical QCMsystem was carried out to investigate the eflects of many factors at the early stages of scale formation. Results indicated there was almost no induction time for this system, and the long induction time observed in the conventional system was due to the limited sensitivity of the analytical balance. A slow increase in scale amount was observed at the beginning of the scaling process as shown by the plot offrequency or mass change against time. After this period the curve rises steeply and becomes almost linear. The supersaturation level of the solutions and the rotating speed have significant effects on the gypsum scaling. A QCM flow-cell system has also been developed to investigate the scaling of gypsum on the pipe wall. This system is similar to a conventional pipe flow system except that its size is much smaller and the deposition of scales can be monitored with the QCM electrode throughout the scaling process. The mass change is plotted against time and results are compared for the rotating QCM system and the conventional system. It is noticed that the formation of gypsum on the QCM electrode is greatly dependent on both the supersaturation of the solution and the flow rate of the fluid passing through the flow cell. [source] Electrolyte Effects on Charge Transport Behavior of [Os(bpy)2(PVP)10Cl]Cl and [Ru(bpy)2(PVP)10Cl]Cl Redox Polymers in Ultra-Thin Films of PolyionsELECTROANALYSIS, Issue 18 2005Bingquan Wang Abstract Metallopolymer films have important applications in electrochemical catalysis. The alternate electrostatic layer-by-layer method was used to assemble films of [Ru(bpy)2(PVP)10Cl]Cl (denoted as ClRu-PVP) and [Os(bpy)2(PVP)10Cl]Cl (ClOs-PVP) metallopolymers onto pyrolytic graphite electrodes. Film thickness estimated by quartz crystal microbalance was 6,8,nm. The effects of pH, electrolyte species and concentration on the electrochemical properties of these electroactive polymers were studied using cyclic voltammetry (CV). Behavior in various electrolytes was compared. Also the mass changes within the ultra-thin film during redox of Os2+/3+ were characterized by in situ electrochemical quartz crystal microbalance (EQCM). The results indicate rapid reversible electron transfer, and show that both ClRu-PVP and ClOs-PVP have compact surface structures while ClOs-PVP is a little denser than ClRu-PVP. Although hydrogen ions do not participate in the chemical reaction of either film, the movement of Na+ cation and water accompanies the redox process of ClOs-PVP films. [source] Foraging effort in relation to the constraints of reproduction in free-ranging albatrossesFUNCTIONAL ECOLOGY, Issue 1 2003S. A. Shaffer Summary 1Theoretical models predict that animals will vary their effort to maximize different currencies such as time and energy when the constraints of reproduction change during breeding, but this has been poorly studied in free-ranging animals. 2Foraging effort (energy per unit time) was examined by comparing mass changes, foraging costs and activity-specific behaviours of Wandering Albatrosses (Diomedea exulans Linnaeus) during the incubation and chick-brooding stages. In 1998, 38 albatrosses (20 during incubation and 18 during brooding) were injected with doubly labelled water and equipped with satellite transmitters and activity data loggers. 3During incubation, albatrosses travelled 3·7 times farther and were at sea 3·2 times longer, yet foraging costs were significantly lower than trips made during brooding (incubation 4·52 ± 0·50 SD W kg,1vs brooding 4·98 ± 0·55 SD W kg,1). 4The rate of daily mass gain decreased significantly with time at sea during incubation whereas the rate of daily mass gain increased significantly with time at sea during brooding. 5Foraging effort was higher during brooding, suggesting that birds were minimizing time at sea to maximize the rate of food delivery to chicks. In contrast, foraging effort was lower during incubation, suggesting that birds were maximizing time at sea and minimizing the energy costs of foraging. 6Foraging costs were also different between sexes. However, this was related to body size differences and not to differences in foraging effort as suggested in previous studies. [source] Evaluating local hydrological modelling by temporal gravity observations and a gravimetric three-dimensional modelGEOPHYSICAL JOURNAL INTERNATIONAL, Issue 1 2010M. Naujoks SUMMARY An approach for the evaluation of local hydrological modelling is presented: the deployment of temporal terrestrial gravity measurements and gravimetric 3-D modelling in addition to hydrological point observations. Of particular interest is to what extent such information can be used to improve the understanding of hydrological process dynamics and to evaluate hydrological models. Because temporal gravity data contain integral information about hydrological mass changes they can be considered as a valuable augmentation to traditional hydrological observations. On the other hand, hydrological effects need to be eliminated from high-quality gravity time-series because they interfere with small geodynamic signals. In areas with hilly topography and/or inhomogeneous subsoil, a simple reduction based on hydrological point measurements is usually not sufficient. For such situations, the underlying hydrological processes in the soil and the disaggregated bedrock need to be considered in their spatial and temporal dynamics to allow the development of a more sophisticated reduction. Regarding these issues interdisciplinary research has been carried out in the surroundings of the Geodynamic Observatory Moxa, Germany. At Moxa, hydrologically induced gravity variations of several 10 nm s,2 are observed by the stationarily operating superconducting gravimeter and by spatially distributed and repeated high-precision measurements with transportable relative instruments. In addition, hydrological parameters are monitored which serve as input for a local hydrological catchment model for the area of about 2 km2 around the observatory. From this model, spatial hydrological variations are gained in hourly time steps and included as density changes of the subsoil in a well-constrained gravimetric 3-D model to derive temporal modelled gravity variations. The gravity variations obtained from this combined modelling correspond very well to the observed hydrological gravity changes for both, short period and seasonal signals. From the modelling the amplitude of the impact on gravity of hydrological changes occurring in different distances to the gravimeter location can be inferred. Possible modifications on the local hydrological model are discussed to further improve the quality of the model. Furthermore, a successful reduction of local hydrological effects in the superconducting gravimeter data is developed. After this reduction global seasonal fluctuations are unmasked which are in correspondence to GRACE observations and to global hydrological models. [source] A model computation of the temporal changes of surface gravity and geoidal signal induced by the evolving Greenland ice sheetGEOPHYSICAL JOURNAL INTERNATIONAL, Issue 3 2001Emmanuel Le Meur Summary This paper deals with present-day gravity changes in response to the evolving Greenland ice sheet. We present a detailed computation from a 3-D thermomechanical ice sheet model that is interactively coupled with a self-gravitating spherical viscoelastic bedrock model. The coupled model is run over the last two glacial cycles to yield the loading evolution over time. Based on both the ice sheet's long-term history and its modern evolution averaged over the last 200 years, results are presented of the absolute gravity trend that would arise from a ground survey and of the corresponding geoid rate of change a satellite would see from space. The main results yield ground absolute gravity trends of the order of ±1 µgal yr,1 over the ice-free areas and total geoid changes in the range between ,0.1 and +0.3 mm yr,1. These estimates could help to design future measurement campaigns by revealing areas of strong signal and/or specific patterns, although there are uncertainties associated with the parameters adopted for the Earth's rheology and aspects of the ice sheet model. Given the instrumental accuracy of a particular surveying method, these theoretical trends could also be useful to assess the required duration of a measurement campaign. According to our results, the present-day gravitational signal is dominated by the response to past loading changes rather than current mass changes of the Greenland ice sheet. We finally discuss the potential of inferring the present-day evolution of the Greenland ice sheet from the geoid rate of change measured by the future geodetic GRACE mission. We find that despite the anticipated high-quality data from satellites, such a method is compromised by the uncertainties in the earth model, the dominance of isostatic recovery on the current bedrock signal, and other inaccuracies inherent to the method itself. [source] Body mass change strategies in blackbirds Turdus merula: the starvation,predation risk trade-offJOURNAL OF ANIMAL ECOLOGY, Issue 2 2005R. MACLEOD Summary 1It is theoretically well established that body mass in birds is the consequence of a trade-off between starvation risk and predation risk. There are, however, no studies of mass variation from sufficiently large wild populations to model in detail the range of diurnal and seasonal mass change patterns in natural populations and how these are linked to the complex environmental and biological variables that may affect the trade-off. 2This study used data on 17 000 individual blackbirds Turdus merula to model how mass changes diurnally and seasonally over the whole year and over a wide geographical area. Mass change was modelled in respect of temperature, rainfall, day length, geographical location, time of day and time of year and the results show how these mass changes vary with individual size, age and sex. 3The hypothesis that seasonal mass is optimized over the year and changes in line with predictors of foraging uncertainty was tested. As theory predicts, reduced day length and reduced temperature result in increased mass and the expected seasonal peak of mass in midwinter. 4The hypothesis that diurnal mass gain is optimized in terms of starvation,predation risk trade-off theory was also tested. The results provide the first empirical evidence for intraspecies seasonal changes in diurnal mass gain patterns. These changes are consistent with shifts in the relative importance of starvation risk and predation risk and with the theory of mass-dependent predation risk. 5In winter most mass was gained in the morning, consistent with reducing starvation risk. In contrast, during the August,November non-breeding period a bimodal pattern of mass gain, with increases just after dawn and before dusk, was adopted and the majority of mass gain occurred at the end of the day consistent with reducing mass-dependent predation risk. The bimodal diurnal mass gain pattern described here is the first evidence that bird species in the wild gain mass in this theoretically predicted pattern. [source] Swimming activity and behaviour of European Anguilla anguilla glass eels in response to photoperiod and flow reversal and the role of energy statusJOURNAL OF FISH BIOLOGY, Issue 9 2009S. Bureau Du Colombier To better understand migratory divergences among Anguilla anguilla glass eels, the behaviour of individuals caught at the time of their estuary entrance was studied through their response to a light:dark cycle and then to both water current reversal and light:dark cycle. In a first experiment, fish moving with the flow in response to dusk (M+ fish) and fish that had not exhibited any movement (M, fish) were distinguished. Anguilla anguilla from these two groups were then individually marked and their response to water current reversal compared. M+ individuals mainly exhibited negative rheotaxis with a tidal periodicity, whereas positive rheotaxis was mainly exhibited by M, individuals. Thus, M+A. anguilla glass eels showing negative rheotaxis appear to have the strongest propensity to migrate, the converse applies to M, ones showing positive rheotaxis. A small percentage of individuals (5%) were hyperactive, alternately swimming with and against the current with almost no resting phase. These fish lost c. 2 mg wet mass day,1, whereas individuals which were almost inactive lost c. 1 mg day,1. Wet and dry mass changes in relation to activity levels were compared with previous experiments and it was concluded that A. anguilla glass eel energy status might be involved in differences in migratory tendencies but other factors that might be important are discussed. It is proposed that any decrease in A. anguilla glass eel energy stores associated with global warming might lead to an increase in the proportion of sedentary individuals and thus be involved in the decrease in the recruitment to freshwater habitats. [source] The effect of biological studies of polyester composites filled carbon black and activated carbon from bamboo (Gigantochloa scortechinii)POLYMER COMPOSITES, Issue 1 2007H.P.S. Abdul Khalil The development of composites using various filler material increased significantly nowadays. Composite materials need to implement the biological and mechanicals impact in their life cycle. The carbon black (CB) and activated carbon (AC) from bamboo (Gigantochloa scortechinii) were used as filler in polyester composites. CB and AC were pyrolized to 700°C and activated with ZnCl2. The composites were prepared with 40% filler loading. The degradation of the composites CB and AC (mechanical properties) to the soil burial test was determined. Tensile, flexural, impact and mass changes of the buried samples were investigated. The deterioration of the samples affected by the biological attack was confirmed by SEM studies. The assessment was done after 0, 3, 6, and 12 months of the biological exposure and the results were compared with the composites filled CaCO3 (commercial filler) and cast polyester resin (as control). POLYM. COMPOS. 28:6,14, 2007. © 2007 Society of Plastics Engineers [source] Chemical and electrochemical synthesis of homopolymer and copolymers of 3-methoxyethoxythiophene with aniline, thiophene and pyrrole for studies of their gas and vapour sensingPOLYMERS FOR ADVANCED TECHNOLOGIES, Issue 9 2001S. Hossein Hosseini Abstract Herein we report chemical and electrochemical formation of poly(3-methoxyethoxythiophene) and its copolymers with aniline, thiophene and pyrrole which give highly conducting polymeric materials. These are soluble in common organic solvents in the conducting state. The response mechanism of these compounds, to a selection of gases and vapours, was investigated using two techniques: measurement of conductance and mass changes using a four probe method and X-ray fluorescence (XRF) device, respectively. Prepared films were exposed to hydrogen halides, hydrogen cyanide, halogens, monochloroacetic acid (MCAA), 1-3-5 trichloromethylbenzene (TCMB), methylbenzyl bromide (MBB), bromoacetone (BA) and cyanogen bromide (CB). These gas sensors may have advantages compared to other sensors in their ability to operate at room temperature, low concentration, stability in air, sufficient diffusion and their selectivity. Copyright © 2001 John Wiley & Sons, Ltd. [source] Effect of short duration electromagnetic field exposures on rat massBIOELECTROMAGNETICS, Issue 1 2002Michelle A. Sandrey Abstract Daily preexposure and postexposure mass measurements of 65 rats (young males and females, old males) a proprietary pulsed wound healing field, pulsed electromagnetic field, (PEMF), or their control fields for 4 h/day for 21 days. Statistical analysis of mass changes over time showed that young rats exposed to PEMF lost more mass and recovered it more slowly compared to controls (2,4% more loss) than did older PEMF exposed rats or any 60 Hz exposed rats. We conclude that daily preexposure and postexposure mass measurements are needed to adequately assess the effects of electromagnetic fields on body mass. Bioelectromagnetics 23:2,6, 2002. © 2002 Wiley-Liss, Inc. [source] | |||||||||||||||||||