In this work instrumental neutron activation analysis was applied todetermine trace elements in nail clippings and to make a comparison betweenthe results obtained from samples from healthy children and those with cysticfibrosis (CF) disease. The findings indicated that fingernails from the CFgroup present higher concentrations of Cl, Cr, K and Na than those found inthe control group. On the other hand, the lowest concentrations for Cr werefound in the CF group. For the Al, As, Co, Fe, Mg, Mn, Se and Zn elementsthere were no differences between the results obtained for the CF and controlgroups. The quality control of the results was evaluated by analysing NIST1577b Bovine Liver and NIST 1566a Oyster Tissue standard reference materials.
Authors:S. White, E. Bork, J. Karst, and J. Cahill
Similarity between seed bank and aboveground vegetation is frequently studied in order to better understand how community composition is affected by factors such as disturbance and succession. Grassland plant communities are known to be sensitive to shifts in precipitation and increases in temperature associated with climate change, but we do not know if and how these factors interact to affect the similarity between seed bank and aboveground vegetation. Also unknown is how the impact of grazing, the dominant land-use in grasslands, will interact with climatic conditions to affect similarity. We manipulated precipitation and temperature, and cut vegetation (as a proxy for grazing) at a grassland site for three years. Percent cover of aboveground vegetation was estimated in the third year, and compared with persistent seed bank samples taken in the year prior from the same plots. Similarity increased with reduced precipitation, was unresponsive to warming, and decreased with clipping. The aboveground community responded strongly to the treatments, while the seed bank community did less so, suggesting similarity responses were largely driven by changes in aboveground vegetation. Because of the importance of the seed bank in vegetation regeneration, understanding the relationship between seed bank and aboveground vegetation will improve our understanding of plant community dynamics under climate change and varied management (grazing) intensities.
We studied biomass and species composition changes of open perennial sand grassland (
) as response to different levels of simulated grazing pressures. We conducted a factorial micro-plot field experiment on previously grazed grassland that has been abandoned for a long time. In a two-way factorial design of 12 treatments × 8 repeats, we performed clipping (twice a year for three years) and litter treatments (removing and adding litter once at the beginning of the experiment) to simulate components of grazing, namely the biomass removal and the reduction of the litter accumulation. We used field spectroscopy and visual canopy cover estimation to measure the effects on the amount of the above-ground green biomass and on the vegetation composition.
Authors:P. C. Favaro, P. Bode, and E. A. De Nadai Fernandes
Trace elements were determined in 27 brands of nail polish using INAA so as to estimate the impact of nail polish remainders when using (finger, toe) nail clippings as a bioindicator for epidemiological studies. Fe was found to be present up to almost 1.7% in one brand. No unambiguous correlation between trace elements and color was established, though transparent polish has the lowest trace element concentrations. An estimate of the maximum effect (no removal of the paint) indicates that over-estimates of some trace element levels in nail with more than 200.000% may occur. This study showed that if nail clippings will be used to study trace elements, very high demands have to be set to the efficiency and selectivity of the cleaning procedure.
The goal of this study was to evaluate the selenium mass fraction in toenail clippings taken from random inhabitants living
in various areas of the Pomeranian (Northern Poland) and Lubuskie (Western Poland) Districts. Toenail clippings were analyzed
by instrumental neutron activation analysis (INAA) giving means of 0.57±0.10 and 0.60±0.16 mg·kg−1 for the two areas, respectively, but the difference was statistically not significant. In additional, it was found that gender,
age, body mass index (BMI), smoking, and selenium supplementation are factors with apparent effects to the selenium levels
in toenail clippings.
Authors:C. Thiel-Egenter, A. Risch, M. Jurgensen, D. Page-Dumroese, B. Krüsi, and M. Schütz
Interactions between grassland ecosystems and vertebrate herbivores are critical for a better understanding of ecosystem processes, but diverge widely in different ecosystems. In this study, we examined plant responses to simulated red deer (
L.) grazing using clip-plot experiments in a subalpine grassland ecosystem of the Central European Alps. We measured aboveground net primary production (ANPP) and phosphorus (P) concentration of leaf tissue from plants of two vegetation types with different grazing history. The experimental plots were placed on a soil-P gradient and subject to two different clipping treatments, which simulated moderate and heavy grazing, respectively. We found distinct differences in the response of both ANPP and P concentration in leaf tissues in the two vegetation types. Compared to moderate, heavy grazing simulation did not affect ANPP in the vegetation type adapted to grazing, but decreased ANPP in the non-grazing adapted vegetation type. High soil-P levels also had different effects on the response of the vegetation to clipping in the two vegetation types with different grazing history. ANPP correlated positively with soil-P in non-grazing adapted tall-grass vegetation, while in grazing adapted short-grass vegetation a positive relationship between soil-P and the P concentration in leaf tissues was found. Our experiments provide data for a better understanding of ecosystem processes in high-elevation grasslands of the Alps with possible implications for both nature conservation purposes in protected areas and the management of agriculturally used grasslands.
Marchand (1960; 1969) presents a unique analysis of back-formation (e.g.,
) as a combination of zero-derivation (
) and clipping (
). This paper will take a closer look at his analysis and argue that its revised version, which uses the notion of conversion rather than zero-derivation, is superior to the mainstream analyses of back-formation. Citing a lot of instances of back-formed verbs, we will show that back-formation does not necessarily delete an affix (e.g.,
), and that it is semantically parallel not to affixation (e.g.,
) but to conversion (e.g.,
). Almost all the preceding analyses fail to deal with these facts, for they are based on the assumption that back-formation deletes a (supposed) affix, or it is the reverse of affixation. Our new analysis, on the other hand, is free from this traditional assumption and can account for various properties of back-formation, including the above two, in terms of general characteristics of conversion and clipping.
Authors:L. Wiebe, S. McQuarrie, C. Ediss, W. Maier-Borst, and F. Helus
Liquid scintillation counting of radionuclides emitting beta radiation with Emax>2 MeV has been investigated. Fluor volume effects were similar to those for low energy beta radiation, and pulse height spectra
broadened in a predictable manner with no pulse clipping up to 4.913 MeV. Large changes in sample channels ratio due to color
quenching resulted in progressively smaller losses of counting efficiency as beta energy increased. Counting efficiences were
estimated to be near 100 percent for34Clm,36Cl,32P and38Cl. Cerenkov counting of38Cl by liquid scintillation counter was volume dependent for both counting efficiency and pulse height spectrum. Counting efficiencies
for34Clm,36Cl,32P and38Cl were estimated to be 57.0, 7.5, 42.7 and 66.3%, respectively. Pulse height spectra were shifted to greater pulse heights
as a function of beta Emax, supporting the possibility of energy discrimination for beta emitters by Cerenkov pulse height spectrum analysis. The advantage
of singles Cerenkov counting over coincidence Cerenkov counting was greatest for36Cl and least for38Cl; this advantage was amplified more for samples of36Cl which had been color quenched than for similarly quenched samples of38Cl or32P.
Authors:J. Brockman, J. Guthrie, J. Morris, J. Davis, R. Madsen, and J. Robertson
The toenail was examined as a biological monitor of Mg, Zn, and Cu intake using an observational case control model. The One
Source Cohort matched 63 individuals in Columbia Missouri who took the One Source multivitamin with 63 control individuals.
The matching criteria were based on age, sex, ethnicity, smoking status, and body mass index. The multivitamin contained supra-nutritional
levels of Se, Mg, Cu, and Zn. The toenail clippings were examined for these elements using instrumental neutron activation
analysis (INAA). A statistical analysis did not indicate a significant difference for Mg, Cu, or Zn between the nails of One
Source supplement users and control subjects (p<0.76, 0.55, and 0.85, respectively). The trace nutrient Se was used as an internal control. Previous studies have consistently
demonstrated that toenail Se is positively correlated with Se supplement use and the analysis did result in a significant
correlation in the toenails of One Source users and control subjects (p<1·10−4). This internal Se control suggests that the One Source Cohort is largely free from misclassification errors that could interfere
with the biomonitor response for the supranutritional intake of Mg, Cu, and Zn.