The impact of changes in the timing of precipitation on the herbaceous understorey of Mediterranean evergreen oak woodlands

Climate change scenarios for the Iberian Peninsula predict increasing temperatures and increasingly variable precipitation regimes, which will challenge the sustainability and biodiversity of Mediterranean ecosystems such as the semi-natural evergreen oak woodlands. To assess the effects of precipitation variability on productivity, species composition and vegetation gas exchange of the understorey vegetation in a typical managed cork oak woodland, a large-scale rainfall manipulation experiment was established. We studied the impacts of a change in the timing of precipitation events on this ecosystem, without altering total annual precipitation inputs. The two water manipulation treatments were: ‘weekly watering treatment’, where natural conditions were simulated with a normal dry period of 7 days, and ‘3-weekly watering treatment’, with the normal dry period increased three-fold to 21 days. Our experimental precipitation patterns resulted in significant differences in temporal soil moisture dynamics between the two treatments. Average soil water content (SWC) at 3 cm depth during the growing season was 16.1 ± 0.17% and 15.8 ± 0.18% in the weekly and 3-weekly watering treatments, respectively, with a mere 5% increase in the variability of SWC when extending the dry period from one to three weeks. Water infiltration into deeper soil layers (>50 cm) was significantly higher in the 3-weekly watering treatment as compared to the weekly watering treatment. This might be beneficial to Quercus suber, the tree component in this ecosystem, as its extensive tree root system enables water acquisition from deeper soil layers. However, manipulation of the within-season precipitation variability, with a shift to fewer, but larger rain events, without change in total precipitation amount, had no significant effect on aboveground net primary productivity (ANPP), belowground net primary productivity (BNPP) and species composition, with average values of peak biomass of 385 g m−2 and 222 g m−2 for ANPP and BNPP, respectively. The experimental precipitation patterns did not result in significant differences in the vegetation gas exchange between the two watering treatments. The CO2 and H2O exchange parameters correlated well with air temperature. In addition, evapotranspiration showed a good correlation with SWC. Incorporating the data of SWC in the conceptual ‘bucket model’ showed that, independently of the watering regime, soil water availability during the life-cycle of these annual plants did not reach severe water stress conditions, which can explain the lack of a significant treatment effect in our study. In addition, our results showed that the annual plant community in these Mediterranean ecosystems is well adapted to short-term drought, through their phenological patterns and physiological adaptations

Tendency to Maximum Complexity in a Non-Equilibrium Isolated System

The time evolution equations of a simplified isolated ideal gas, the "tetrahe- dral" gas, are derived. The dynamical behavior of the LMC complexity [R. Lopez-Ruiz, H. L. Mancini, and X. Calbet, Phys. Lett. A 209, 321 (1995)] is studied in this system. In general, it is shown that the complexity remains within the bounds of minimum and maximum complexity. We find that there are certain restrictions when the isolated "tetrahedral" gas evolves towards equilibrium. In addition to the well-known increase in entropy, the quantity called disequilibrium decreases monotonically with time. Furthermore, the trajectories of the system in phase space approach the maximum complexity.Comment: 22 pages, 0 figures. Published in Phys. Rev. E 63, 066116(9) (2001

PRODUÇÃO DE SEDIMENTOS SUSPENSOS NA BACIA DO RIO PARAÍBA-PB

O objetivo deste trabalho foi caracterizar o regime hidrossedimentológico do Rio Paraíba. Foram utilizados dados disponíveis no site da ANA, e realizados tratamentos estatísticos. As maiores vazões foram nas décadas de 70 e 80, enquanto a de 90 apresentou baixos valores. A produção de sedimento suspenso no médio curso foi em média de 9,846 t/km².ano-1, enquanto no baixo foi de 1,765 t/km².ano-1. Estes dados confirmaram a forte influência dos açudes no regime hidrossedimentológico da bacia

Survey of 800+ data sets from human tissue and body fluid reveals xenomiRs are likely artifacts

miRNAs are small 22-nucleotide RNAs that can post-transcriptionally regulate gene expression. It has been proposed that dietary plant miRNAs can enter the human bloodstream and regulate host transcripts; however, these findings have been widely disputed. We here conduct the first comprehensive meta-study in the field, surveying the presence and abundances of cross-species miRNAs (xenomiRs) in 824 sequencing data sets from various human tissues and body fluids. We find that xenomiRs are commonly present in tissues (17%) and body fluids (69%); however, the abundances are low, comprising 0.001% of host human miRNA counts. Further, we do not detect a significant enrichment of xenomiRs in sequencing data originating from tissues and body fluids that are exposed to dietary intake (such as liver). Likewise, there is no significant depletion of xenomiRs in tissues and body fluids that are relatively separated from the main bloodstream (such as brain and cerebro-spinal fluids). Interestingly, the majority (81%) of body fluid xenomiRs stem from rodents, which are a rare human dietary contribution but common laboratory animals. Body fluid samples from the same studies tend to group together when clustered by xenomiR compositions, suggesting technical batch effects. Last, we performed carefully designed and controlled animal feeding studies, in which we detected no transfer of plant miRNAs into rat blood, or bovine milk sequences into piglet blood. In summary, our comprehensive computational and experimental results indicate that xenomiRs originate from technical artifacts rather than dietary intake

Enhancing studies of the connectome in autism using the autism brain imaging data exchange II

The second iteration of the Autism Brain Imaging Data Exchange (ABIDE II) aims to enhance the scope of brain connectomics research in Autism Spectrum Disorder (ASD). Consistent with the initial ABIDE effort (ABIDE I), that released 1112 datasets in 2012, this new multisite open-data resource is an aggregate of resting state functional magnetic resonance imaging (MRI) and corresponding structural MRI and phenotypic datasets. ABIDE II includes datasets from an additional 487 individuals with ASD and 557 controls previously collected across 16 international institutions. The combination of ABIDE I and ABIDE II provides investigators with 2156 unique cross-sectional datasets allowing selection of samples for discovery and/or replication. This sample size can also facilitate the identification of neurobiological subgroups, as well as preliminary examinations of sex differences in ASD. Additionally, ABIDE II includes a range of psychiatric variables to inform our understanding of the neural correlates of co-occurring psychopathology; 284 diffusion imaging datasets are also included. It is anticipated that these enhancements will contribute to unraveling key sources of ASD heterogeneity

Femtosecond X-ray diffraction from an aerosolized beam of protein nanocrystals

High-resolution Bragg diffraction from aerosolized single granulovirus nanocrystals using an X-ray free-electron laser is demonstrated. The outer dimensions of the in-vacuum aerosol injector components are identical to conventional liquid-microjet nozzles used in serial diffraction experiments, which allows the injector to be utilized with standard mountings. As compared with liquid-jet injection, the X-ray scattering background is reduced by several orders of magnitude by the use of helium carrier gas rather than liquid. Such reduction is required for diffraction measurements of small macromolecular nanocrystals and single particles. High particle speeds are achieved, making the approach suitable for use at upcoming high-repetition-rate facilities.Use of the Linac Coherent Light Source (LCLS), SLAC National Accelerator Laboratory, is supported by the US Department of Energy, Office of Science, Office of Basic Energy Sciences under contract No. DE-AC02-76SF00515. Parts of the sample delivery system used at LCLS for this research were funded by the NIH grant P41GM103393, formerly P41RR001209. In addition to DESY, this work has been supported by the excellence cluster ‘The Hamburg Center for Ultrafast Imaging – Structure, Dynamics and Control of Matter at the Atomic Scale’ of the Deutsche Forschungsgemeinschaft (CUI, DFG-EXC1074), the Gottfried Wilhelm Leibniz Program of the DFG, the European Research Council under the European Union’s Seventh Framework Programme (FP7/2007–2013) through the Synergy Grant AXSIS (ERC-2013-SyG 609920) and the Consolidator Grant COMOTION (ERC-Ku¨pper-614507), the Helmholtz Association ‘Initiative and Networking Fund’, and the Australian Research Council’s Discovery Projects funding scheme (DP170100131). RAK acknowledges support from an NSF STC award (1231306)