Search

The invasion of aquifer microbial communities by aboveground microorganisms, a phenomenon known as community coalescence, is likely to be exacerbated in groundwaters fed by stormwater infiltration systems (SISs). Here, the incidence of this increased connectivity with upslope soils and impermeabilized surfaces was assessed through a meta-analysis of 16S rRNA gene libraries. Specifically, DNA sequences encoding 16S rRNA V5-V6 regions from free-living and attached aquifer bacteria (i.e., water and biofilm samples) were analysed upstream and downstream of a SIS and compared with those from bacterial communities from watershed runoffs and surface sediments from the SIS detention and infiltration basins. Significant bacterial transfers were inferred by the SourceTracker Bayesian approach, with 23 % to 57 % of the aquifer bacterial biofilms being composed of taxa from aboveground sediments and urban runoffs. Sediments from the detention basin were found more significant contributors of taxa involved in the buildup of these biofilms than soils from the infiltration basin. Inferred taxa among the coalesced biofilm community were predicted to be high in hydrocarbon degraders such as Sphingobium and Nocardia. The 16S rRNA-based bacterial community structure of the downstream-SIS aquifer waters showed lower coalescence with aboveground taxa (8 % to 38 %) than those of biofilms and higher numbers of taxa predicted to be involved in the N and S cycles. A DNA marker named tpm enabled the tracking of bacterial species from 24 genera including Pseudomonas, Aeromonas and Xanthomonas, among these communities. Several tpm sequence types were found to be shared between the aboveground and aquifer samples. Reads related to Pseudomonas were allocated to 50 species, of which 16 were found in the aquifer samples. Several of these aquifer species were found to be involved in denitrification but also hydrocarbon degradation (P. aeruginosa, P. putida and P. fluorescens). Some tpm sequence types allocated to P. umsongensis and P. chengduensis were found to be enriched among the tpm-harbouring bacteria, respectively, of the aquifer biofilms and waters. Reads related to Aeromonas were allocated to 11 species, but only those from A. caviae were recovered aboveground and in the aquifer samples. Some tpm sequence types of the X. axonopodis phytopathogen were recorded in higher proportions among the tpm-harbouring bacteria of the aquifer waters than in the aboveground samples. A significant coalescence of microbial communities from an urban watershed with those of an aquifer was thus observed, and recent aquifer biofilms were found to be significantly colonized by runoff-opportunistic taxa able to use urban C sources from aboveground compartments.

IntroductionVeterans are at greater risk for suicide than non-veterans; veterans who call the Veterans Crisis Line are at even higher risk. Firearms and poisoning are among the most common methods by which people die by suicide in the United States and access to those lethal means are risk factors for suicide. The United States Department of Veterans Affairs’ Veterans Crisis Line conducted a six-month pilot to enhance lethal means safety counseling conversations by mailing lethal means safety devices (cable gun locks and/or medication takeback envelopes) to veteran callers.Materials and methodsVeterans Crisis Line responders were selected based on quality assurance ratings, received training, and passed a knowledge check prior to participating. Veterans were eligible if they were calling for themselves and had access to firearms and/or surplus medications. The pilot was assessed using operational data and qualitative interviews with responders to assess their experience, barriers and facilitators, and suggestions for improvement.ResultsResponders documented 8,323 calls from 7,005 unique phone numbers; 10.8% were eligible for cable gun locks and 8.7% were eligible for medication takeback envelopes. Responders offered cable gun locks to 652 veterans and medication takeback envelopes to 522 veterans. A total of 465 cable gun locks and 567 medication takeback envelopes were mailed to 307 veterans. Operationally, there was little impact of the pilot on call handle time. Five responders participated in qualitative interviews. They reported feeling comfortable incorporating mailing devices into their work and reported that response from veterans was positive. Their most frequent suggestion for improvement was additional training.DiscussionResults demonstrate that mailing these devices to veterans was feasible and acceptable. Call handle time results show that the Veterans Crisis Line would not need additional personnel to manage changes in call handle time associated with offering devices to all veteran callers. Full implementation of this program will require updates to procedures and policies, training, documentation system changes, additional logistical support for mailing, and a plan for ongoing evaluation.

Different friable Hevea callus lines from the same genotype can display different embryogenic and regenerative potentials. These lines can not be distinguished on the basis of macroscopic criteria. A histological and molecular study was undertaken to characterize the differences existing between five callus lines with different potentials. The genes differentially expressed during induction were analyzed using the differential display (DD-RT) technique. Twenty-eight cDNAs were found to be differentially expressed during induction in the embryogenic regenerating line (ER). Embryogenic nodules were formed earlier in the ER lines than in the embryogenic non-regenerating lines and were completely absent in the non-embryogenic line. Of these 28 cDNAs, five could be used to distinguish between calli prior to induction, thereby enabling an early diagnosis of friable Hevea callus embryogenic potential. [ABSTRACT FROM AUTHOR]

Ions densities and mobilities in post-dielectric barrier discharge (post-DBD) are presented here. To extract ions from DBD and perform post-discharge measurements the best functioning conditions are low overpressure, high frequency ([?] 25 kHz, to avoid electrocollection) and low flow rate (1 lpm, to reduce dilution). Besides, ions densities in post-discharge increase with electrode temperature and, at low flow rates, with the number of discharge filaments by time and surface unit (controlled by voltage at fixed frequency). In both cases, the reinforcement of dielectric material surface polarization reduces the local electrocollection of ions inside DBD or increases the production of ions by subcritical avalanches outside filaments. Concerning mobility measurements, it is shown that for low saturation, vapours emitted from post-DBD polymer tubes only affect positive ions mobility due to selective ion-induced nucleation on positive ions. When metal post-DBD tubes are used, positive ions keep the same range of electric mobility at any temperature while there is a drop in negative ions mobility around 100 degC, probably related to a chemical transition between O3 and NOx. [ABSTRACT FROM AUTHOR]

The paper highlights applications of some atmospheric pressure plasmas (dc-corona, streamer and spark and ac-Dielectric Barrier Discharges) to aerosol processes for Materials and Environment (filtration, diagnostics). The production of vapor i.e. condensable gaseous species, leads to nano-sized particles by physical and chemical routes of nucleation in these AP plasmas: (i) when dc streamer and spark filamentary discharges as well as ac filamentary dielectric barrier discharges interact with metal or dielectric surfaces, and (ii) when discharges induce reactions with gaseous precursors in volume. It is shown how composition, size and structure of primary nano-particles are related to plasma parameters (energy, number per unit surface and time and thermal gradients). Then the growth by coagulation controls the final size of agglomerates versus plasma parameters and transit time in and after the plasma. Charging and electro-thermal collection are depicted to account for the related potential applications of controlled kinematics of charged aerosol. [ABSTRACT FROM AUTHOR]

A soil-embedded optical fiber sensing cable is evaluated for an embedded cavity detection and sinkhole warning system in railway tunnels. Tests were performed on a decametric structure equipped with an embedded 110 m long fiber optic cable. Both Brillouin optical time-domain reflectometry (B-OTDR) and optical frequency-domain reflectometry (OFDR) sensing techniques were used for cable interrogation, yielding results that were in good qualitative agreement with finite-element calculations. Theoretical and experimental comparison enabled physical interpretation of the influence of ground properties, and the analysis of embedded cavity size and position. A 5 mm embedded cavity located 2 m away from the sensing cable was detected. The commercially available sensing cable remained intact after soil collapse. Specificities of each technique are analyzed in view of the application requirements. For tunnel monitoring, the OFDR technique was determined to be more viable than the B-OTDR due to higher spatial resolution, resulting in better detection and size determination of the embedded cavities. Conclusions of this investigation gave outlines for future field use of distributed strain-sensing methods under railways and more precisely enabled designing a warning system suited to the Ebersviller tunnel specificities. [ABSTRACT FROM AUTHOR]