Instability driven flow and runoff formation in a small catchment

Two anomalous phenomena were observed in a small catchment: 1) In some situations, the water supplied by rain caused a pronounced decrease in the soil water content. 2) In these periods, the soil water movement could be explained only by assuming an irregularly oscillating outflow of soil water into lower horizons. In these situations a large volume of water flows through the soil; therefore on the hydrological scale, this phenomenon forms a great part of the outflow from a watershed. These phenomena are described in the frame of the instability driven flow theory and explained as consequences of the porous soil body's capacity to become conductive as a result of a very little change of its moisture. Therefore the soil profile can attenuate or amplify the rainfall pulses during their transformation to the outflow below the soil profile. If the soil water content is lower than the threshold value, the rainfall pulses can be suppressed down to zero. If the soil profile contains more water, the soil does not attenuate the rainfall pulses, it can even amplify them by adding the released soil water. This is the mechanism of rapid growth of rising hydrograph limb during a storm event. The rapid transport of the soil water can occur in any part of the porous soil body regardless of the pore size and can be caused by any rainfall event with any intensity, duration or total volume

Application of minidisk infiltrometer to estimate water repellency in Mediterranean pine forest soils

Assessment of soil water repellency (SWR) was conducted in the decomposed organic floor layer (duff) and in the mineral soil layer of two Mediterranean pine forests, one in Italy and the other in Spain, by the widely-used water drop penetration time (WDPT) test and alternative indices derived from infiltration experiments carried out by the minidisk infiltrometer (MDI). In particular, the repellency index (RI) was calculated as the adjusted ratio between ethanol and water soil sorptivities whereas the water repellency cessation time (WRCT) and the specifically proposed modified repellency index (RIm) were derived from the hydrophobic and wettable stages of a single water infiltration experiment. Time evolution of SWR and vegetation cover influence was also investigated at the Italian site. All indices unanimously detected severe SWR conditions in the duff of the pine forests. The mineral subsoils in the two forests showed different wettability and the clay-loam subsoil at Ciavolo forest was hydrophobic even if characterized by organic matter (OM) content similar to the wettable soil of an adjacent glade. It was therefore assumed that the composition rather than the total amount of OM influenced SWR. The hydraulic conductivity of the duff differed by a factor of 3.8-5.8 between the two forested sites thus influencing the vertical extent of SWR. Indeed, the mineral subsoil of Javea showed wettable or weak hydrophobic conditions probably because leaching of hydrophobic compounds was slowed or prevented at all. Estimations of SWR according to the different indices were in general agreement even if some discrepancies were observed. In particular, at low hydrophobicity levels the SWR indices gathered from the MDI tests were able to signal sub-critical SWR conditions that were not detected by the traditional WDPT index. The WRCT and modified repellency index RIm yielded SWR estimates in reasonable agreement with those obtained with the more cumbersome RI test and, therefore, can be proposed as alternative procedures for SWR assessment

The Effect of Heating on Properties of Sandy Soils

Although burning grass and crop residues is prohibited in many countries, farmers perceive it as a quick and inexpensive way to eliminate unwanted biomass. The aim of this study was to estimate the impact of heating temperature (simulation of biomass burning) on the studied properties (soil organic carbon (SOC) content, pH(H2O), water drop penetration time, WDPT, and contact angle, CA) of acidic sandy soils. Soil samples were taken from the experimental sites S1, S2, and S3 at Studienka village in the Borská nížina lowland (southwestern Slovakia). Experimental site S1 was arable land, experimental site S2 was arable land abandoned for approximately 10 years, and experimental site S3 was arable land abandoned for approximately 30 years with scattered Scots pine (Pinus sylvestris L.) trees. It was found that all the soil properties studied were strongly affected by heating. A drop in SOC was observed in all the soils for the heating temperature between 20 and 600 °C. Due to the incomplete combustion of SOC, a small (0.1–0.7%) SOC content was recorded even in soils heated to between 600 and 900 °C. An increase in pH(H2O) was observed in all the soils for the heating temperature higher than 300 °C. Soil from the experimental site S1 was wettable (WDPT < 5 s) for all of the heating temperatures. WDPT vs. heating temperature relationships for the soils from the experimental sites S2 and S3 were more complex. After a decrease in the heating temperature of 50 °C, an increase in WDPT for the heating temperature between 50 °C and 300 °C (for S3 soil) and 350 C (for S2 soil) was registered. Finally, the WDPT dramatically dropped to 0 for the heating temperature of 350 °C (for S3 soil) and 400 °C (for S2 soil). CA started to decrease at 300 °C in all the soils and dropped to 0° for all the soils at 800 °C. CA > 0° measured in soils for the heating temperature between 400 and 800 °C, as a consequence of the small SOC contents due to the incomplete combustion of SOC, is a novelty of this study which demonstrates that CA is more sensitive to the changes in subcritical water repellency than WDPT

Comparison of two methods to assess heterogeneity of water flow in soils

The heterogeneity of water flow and solute transport was assessed during radioactive tracer infiltration experiment in a black clay loam soil using modified methods to estimate the effective cross section (ECS) and the degree of preferential flow (DPF). The results of field and numerical experiments showed that these parameters characterized the heterogeneity of water flow in the soils unequivocally. The ECS decreases non-linearly and the DPF increases linearly with an increase of the bypassing ratio (ratio of macropore flow rate to total flow rate). The ECS decreased and the DPF increased with depth, which suggests an increase in the heterogeneity of water flow with depth. The plot of the DPF against ECS values calculated from the tracer experiment data was consistent with the relationship obtained by the numerical simulation assuming preferential flow in the neighbourhood of three probes

Invigorating hydrological research through journal publications

Over the past five years, the editors of a number of journals in the discipline of hydrology have met informally to discuss challenges and concerns in relation to the rapidly changing publishing landscape. Two of the previous meetings, in Götenborg in July 2013 and in Prague in June 2015, were followed by joint editorials (Blöschl et al. 2014; Koutsoyiannis et al. 2016) published in all participating journals. A meeting was convened in Vienna in April 2017 [during the General Assembly of the European Geosciences Union (EGU)] that was attended by 21 editors representing 14 journals. Even though the journals are published in very different settings, the editors found common cause in a vision of the editor’s role beyond just that of gatekeeper ensuring high-quality publications, to also being critical facilitators of scientific advances. In that enabling spirit, we as editors acknowledge the need to anticipate and adapt to the changing publishing landscape. This editorial communicates our views on the implications for authors, readers, reviewers, institutional assessors, and the community of editors, as discussed during the meeting and subsequently

A Re-Examination of Global Suppression of RNA Interference by HIV-1

The nature of the interaction between replicating HIV-1 and the cellular RNAi pathway has been controversial, but it is clear that it can be complex and multifaceted. It has been proposed that the interaction is bi-directional, whereby cellular silencing pathways can restrict HIV-1 replication, and in turn, HIV-1 can suppress silencing pathways. Overall suppression of RNAi has been suggested to occur via direct binding and inhibition of Dicer by the HIV-1 Tat protein or through sequestration of TRBP, a Dicer co-factor, by the structured TAR element of HIV-1 transcripts. The role of Tat as an inhibitor of Dicer has been questioned and our results support and extend the conclusion that Tat does not inhibit RNAi that is mediated by either exogenous or endogenous miRNAs. Similarly, we find no suppression of silencing pathways in cells with replicating virus, suggesting that viral products such as the TAR RNA elements also do not reduce the efficacy of cellular RNA silencing. However, knockdown of Dicer does allow increased viral replication and this occurs at a post-transcriptional level. These results support the idea that although individual miRNAs can act to restrict HIV-1 replication, the virus does not counter these effects through a global suppression of RNAi synthesis or processing

A multiplatform approach identifies miR-152-3p as a common epigenetically regulated onco-suppressor in prostate cancer targeting TMEM97

Prostate cancer (PCa) is a major cause of morbidity and mortality in men worldwide. MicroRNAs are globally downregulated in PCa, especially in poorly differentiated tumors. Nonetheless, the underlying mechanisms are still elusive. Herein, using combined analysis of microRNAs expression and genomewide DNA methylation, we aimed to identify epigenetically downregulated microRNAs in PCa.Research Center of Portuguese Oncology Institute of Porto (FB-GEBC-27 and 19-CI-IPOP-2016). JR-C and CSG are supported by FCT- Fundação para a Ciência e Tecnologia PhD fellowships (SFRH/BD/71293/2010 and SFRH/BD/92786/2013), SS is supported by a PhD fellowship IPO/ESTIMA-1 NORTE-01-0145-FEDER-000027, and IG is a research fellow from the strategic funding of FCT (PCT: PEst- UID/DTP/00776/2013 and COMPETE: POCI-01-0145-FEDER-006868). BMC is funded by FCT-Fundação para a Ciência e a Tecnologia (IF/00601/2012)info:eu-repo/semantics/publishedVersio

Involvement of microRNA Lethal-7a in the Regulation of Embryo Implantation in Mice

MicroRNAs interact with multiple mRNAs resulting in their degradation and/or translational repression. This report used the delayed implantation model to determine the role of miRNAs in blastocysts. Dormant blastocysts in delayed implanting mice were activated by estradiol. Differential expression of 45 out of 238 miRNAs examined was found between the dormant and the activated blastocysts. Five of the nine members of the microRNA lethal-7 (let-7) family were down-regulated after activation. Human blastocysts also had a low expression of let-7 family. Forced-expression of a family member, let-7a in mouse blastocysts decreased the number of implantation sites (let-7a: 1.1±0.4; control: 3.8±0.4) in vivo, and reduced the percentages of blastocyst that attached (let-7a: 42.0±8.3%; control: 79.0±5.1%) and spreaded (let-7a: 33.5±2.9%; control: 67.3±3.8%) on fibronectin in vitro. Integrin-β3, a known implantation-related molecule, was demonstrated to be a target of let-7a by 3′-untranslated region reporter assay in cervical cancer cells HeLa, and Western blotting in mouse blastocysts. The inhibitory effect of forced-expression of let-7a on blastocyst attachment and outgrowth was partially nullified in vitro and in vivo by forced-expression of integrin-β3. This study provides the first direct evidence that let-7a is involved in regulating the implantation process partly via modulation of the expression of integrin-β3. (200 words)