Hydrogeologic Investigations of Pavement Subsidence in the Cumberland Gap Tunnel

Cumberland Gap Tunnel was constructed under Cumberland Gap National Historical Park in 1996 to improve transportation on a segment of U.S. 25E, connecting Kentucky and Tennessee and restoring Cumberland Gap to its historical appearance. The concrete pavement in the tunnel started to subside in 2001. Ground penetrating radar surveys revealed voids in many areas of the limestone roadbed aggregate beneath the pavement. To investigate possible hydrogeologic processes that may have caused favorable conditions for voids to form in the aggregate, we studied geology, groundwater flow, and groundwater chemistry in the tunnel using a variety of methods, including bore drilling, packer test, dye tracing, groundwater- and surface-flow monitoring, water-chemistry modeling, and an aggregate dissolution experiment. The study revealed that the aggregate receives a large volume of groundwater from much of the bedrock invert, but the flow velocity is too slow to transport small particles out of the aggregate. Calcite saturation indices calculated from water-chemistry data suggest that the groundwater was capable of continuously dissolving calcite, the primary mineral in the limestone aggregate. Water samples taken during different flow conditions indicate that groundwater under low-flow conditions. The dissolution experiment showed that all the limestone aggregate placed beneath the roadbed and in contact with groundwater lost mass; the highest mass loss was 3.4 percent during a 178-day period. The experiment also suggested that water with higher calcite-dissolving potential removed limestone mass quicker than water with low calcite-dissolving potential. We recommend that the limestone aggregate be replaced with noncarbonate aggregate, such as granite, to prevent dissolution and future road subsidence

RNAcentral : a hub of information for non-coding RNA sequences

RNAcentral is a comprehensive database of non-coding RNA (ncRNA) sequences, collating information on ncRNA sequences of all types from a broad range of organisms. We have recently added a new genome mapping pipeline that identifies genomic locations for ncRNA sequences in 296 species. We have also added several new types of functional annotations, such as tRNA secondary structures, Gene Ontology annotations, and miRNA-target interactions. A new quality control mechanism based on Rfam family assignments identifies potential contamination, incomplete sequences, and more. The RNAcentral database has become a vital component of many workflows in the RNA community, serving as both the primary source of sequence data for academic and commercial groups, as well as a source of stable accessions for the annotation of genomic and functional features. These examples are facilitated by an improved RNAcentral web interface, which features an updated genome browser, a new sequence feature viewer, and improved text search functionality. RNAcentral is freely available at https://rnacentral.org

Spatial Geographic Mosaic in an Aquatic Predator-Prey Network

The geographic mosaic theory of coevolution predicts 1) spatial variation in predatory structures as well as prey defensive traits, and 2) trait matching in some areas and trait mismatching in others mediated by gene flow. We examined gene flow and documented spatial variation in crushing resistance in the freshwater snails Mexipyrgus churinceanus, Mexithauma quadripaludium, Nymphophilus minckleyi, and its relationship to the relative frequency of the crushing morphotype in the trophically polymorphic fish Herichthys minckleyi. Crushing resistance and the frequency of the crushing morphotype did show spatial variation among 11 naturally replicated communities in the Cuatro Ciénegas valley in Mexico where these species are all endemic. The variation in crushing resistance among populations was not explained by geographic proximity or by genetic similarity in any species. We detected clear phylogeographic patterns and limited gene flow for the snails but not for the fish. Gene flow among snail populations in Cuatro Ciénegas could explain the mosaic of local divergence in shell strength and be preventing the fixation of the crushing morphotype in Herichthys minckleyi. Finally, consistent with trait matching across the mosaic, the frequency of the fish morphotype was negatively correlated with shell crushing resistance likely reflecting the relative disadvantage of the crushing morphotype in communities where the snails exhibit relatively high crushing resistance

Thermal Excitation of Gadolinium-Based Contrast Agents Using Spin Resonance.

Theoretical and experimental investigations into the thermal excitation of liquid paramagnetic contrast agents using the spin resonance relaxation mechanism are presented. The electronic spin-lattice relaxation time τ1e of gadolinium-based contrast agents, which is estimated at 0.1 ns, is ten orders of magnitude faster than the relaxation time of protons in water. The shorter relaxation time is found to significantly increase the rate of thermal energy deposition. To the authors' knowledge this is the first study of gadolinium based contrast agents in a liquid state used as thermal agents. Analysis shows that when τ1e and other experimental parameters are optimally selected, a maximum theoretical heating rate of 29.4 °C.s-1 could be achieved which would suffice for clinical thermal ablation of neoplasms. The experimental results show a statistically significant thermal response for two out of the four contrast agents tested. The results are compared to the simulated estimates via analysis of a detailed model of the system. While these experimentally determined temperature rises are small and thus of no clinical utility, their presence supports the theoretical analysis and strongly suggests that the chemical structure of the selected compounds plays an important role in this mechanism of heat deposition. There exists an opportunity for the development of alternative gadolinium-based compounds with an order of magnitude longer τ1e in a diluted form to be used as an efficient hyperthermia agent for clinical use

Experimental values used to calculate the spin-power and resulting temperature rate, with the electronic spin relaxation times <i>τ</i>_1<i>e</i> and <i>τ</i>_2<i>e</i> obtained from Rast and Atsarkin [12, 13].

<p>Experimental values used to calculate the spin-power and resulting temperature rate, with the electronic spin relaxation times <i>τ</i>_1<i>e</i> and <i>τ</i>_2<i>e</i> obtained from Rast and Atsarkin [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0158194#pone.0158194.ref012" target="_blank">12</a>, <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0158194#pone.0158194.ref013" target="_blank">13</a>].</p

Slope values <i>b</i>, with subscript definitions 1 = On/cOn and 2 = Off/cOff states, and comparison results performed on experimental datasets.

<p>Slope values <i>b</i>, with subscript definitions 1 = On/cOn and 2 = Off/cOff states, and comparison results performed on experimental datasets.</p

Model parameters used to fit the pulse and decay responses of the ProHance solution.

<p>Model parameters used to fit the pulse and decay responses of the ProHance solution.</p