Manganese hyperaccumulation capacity of Ilex paraguariensis A. St. Hil. and occurrence of interveinal chlorosis induced by transient toxicity.

Manganese (Mn) toxicity is common in plants grown on very acid soils. However, some plants species that grow in this condition can take up high amounts of Mn and are referred to as hyperaccumulating species. In this study, we evaluated the capacity of Ilex paraguariensis to accumulate Mn and the effect of excessive concentrations on plant growth and nutrition. For this, a container experiment was conducted using soils from different parent materials (basalt and sandstone), with and without liming, and at six doses of applied Mn (0, 30, 90, 270, 540 and 1,080 mg kg 1). Clonal plants grown for 203 days were harvested to evaluate yield, and leaf tissue samples were evaluated for Mn and other elements. Without liming and with high Mn doses, leaf Mn concentrations reached 13,452 and 12,127 mg kg 1 in sandstone and basalt soils, respectively; concentrations in excess of 10,000 mg kg 1 are characteristic of hyperaccumulating plants. Liming reduced these values to 7203 and 8030 mg kg 1. More plant growth accompanied increased Mn leaf concentrations, with a growth reduction noted at the highest dose in unlimed soils. Elemental distribution showed Mn presence in the mesophyll, primarily in vascular bundles, without high Mn precipitates. Interveinal chlorosis of young leaves associated with high Mn concentration and lower Fe concentrations was observed, especially in sandstone soil without liming. However, the occurrence of this symptom was not associated with decreased plant growth

Influence of spin fluctuations on the superconducting transition temperature and resistivity in the t-J model at large N

Spin fluctuations enter the calculation of the superconducting transition temperature T$_c$ only in the next-to-leading order (i.e., in O(1/N$^2$) of the 1/N expansion of the t-J model. We have calculated these terms and show that they have only little influence on the value of T$_c$ obtained in the leading order O(1/N) in the optimal and overdoped region, i.e., for dopings larger than the instability towards a flux phase. This result disagrees with recent spin-fluctuation mediated pairing theories. The discrepancies can be traced back to the fact that in our case the coupling between electrons and spins is determined by the t-J model and not adjusted and that the spin susceptibility is rather broad and structureless and not strongly peaked at low energies as in spin-fluctuation models. Relating T$_c$ and transport we show that the effective interactions in the particle-particle and particle-hole channels are not simply related within the 1/N expansion by different Fermi surface averages of the same interactin as in the case of phonons or spin fluctuations. As a result, we find that large values for T$_c$ and rather small scattering rates in the normal state as found in the experiments can easily be reconciled with each other. We also show that correlation effects heavily suppress transport relaxation rates relative to quasiparticle relaxation rates in the case of phonons but not in the case of spin fluctuations.Comment: 16 pages, 10 figures, will appear in Phys. Rev.

Selection of Reference Genes for RT-qPCR Studies in Different Organs of Rice Cultivar BRS AG Submitted to Recurrent Saline Stress.

Quantitative real-time polymerase chain reactions (RT-qPCR) have become one of the most widely used methods for analyzing gene expression, provided suitable reference genes are available to normalize the data. RNA was isolated from leaves, grain, rachises and sheaths of rice (Oryza sativa L. cv. BRS AG) submitted to different saline stress events for seven days, and expression analysis was carried out by RT-qPCR. Expression levels of ten candidate reference genes were assessed, actin11 (ACT11), ubiquitin conjugating enzyme E2 (UBC-E2), eukaryotic elongation factor1-a (Eef-1a), glyceraldehyde-3-phosphate dehydrogenase (GAPDH), B-tubulin (B-Tub), eukaryotic initiation factor 4a (Eif-4-a), ubiquitin10 (UBQ10), ubiquitin5 (UBQ5), aquaporin TIP41 (TIP41-like). Gene expression stability was calculated using the common statistical algorithms geNorm, BestKeeper and ?Ct method, NormFinder and RefFinder. The most stably expressed genes were UBC2E and GAPDH for leaves, UBQ5 and UBQ10 for sheaths, TIP41 and UBQ10 for rachises, and TIP41 and cyclophilin for grain. Gene expression of triose phosphate translocator (TPT1), ADP-glucose transporter (BT1-1), choline monooxygenase (CMO) was used to validate the selected reference genes. The results highlighted the importance of using suitable reference gene to normalize gene expression data in rice plants

DNA Methods to Identify Missing Persons

Human identification by DNA analysis in missing person cases typically involves comparison of two categories of sample: a reference sample, which could be obtained from intimate items of the person in question or from family members, and the questioned sample from the unknown person-usually derived from the bones, teeth, or soft tissues of human remains. Exceptions include the analysis of archived tissues, such as those held by hospital pathology departments, and the analysis of samples relating to missing, but living persons. DNA is extracted from the questioned and reference samples and well-characterized regions of the genetic code are amplified from each source using the Polymerase Chain Reaction (PCR), which generates sufficient copies of the target region for visualization and comparison of the genetic sequences obtained from each sample. If the DNA sequences of the questioned and reference samples differ, this is normally sufficient for the questioned DNA to be excluded as having come from the same source. If the sequences are identical, statistical analysis is necessary to determine the probability that the match is a consequence of the questioned sequence coming from the same individual who provided the reference sample or from a randomly occurring individual in the general population. Match probabilities that are currently achievable are frequently greater than 1 in 1 billion, allowing identity to be assigned with considerable confidence in many cases