Managing and Sharing the Risks of Drought in Australia

Resource /Energy Economics and Policy,

Stand-replacing wildfires increase nitrification for decades in southwestern ponderosa pine forests.

Stand-replacing wildfires are a novel disturbance within ponderosa pine (Pinus ponderosa) forests of the southwestern United States, and they can convert forests to grasslands or shrublands for decades. While most research shows that soil inorganic N pools and fluxes return to pre-fire levels within a few years, we wondered if vegetation conversion (ponderosa pine to bunchgrass) following stand-replacing fires might be accompanied by a long-term shift in N cycling processes. Using a 34-year stand-replacing wildfire chronosequence with paired, adjacent unburned patches, we examined the long-term dynamics of net and gross nitrogen (N) transformations. We hypothesized that N availability in burned patches would become more similar to those in unburned patches over time after fire as these areas become re-vegetated. Burned patches had higher net and gross nitrification rates than unburned patches (P < 0.01 for both), and nitrification accounted for a greater proportion of N mineralization in burned patches for both net (P < 0.01) and gross (P < 0.04) N transformation measurements. However, trends with time-after-fire were not observed for any other variables. Our findings contrast with previous work, which suggested that high nitrification rates are a short-term response to disturbance. Furthermore, high nitrification rates at our site were not simply correlated with the presence of herbaceous vegetation. Instead, we suggest that stand-replacing wildfire triggers a shift in N cycling that is maintained for at least three decades by various factors, including a shift from a woody to an herbaceous ecosystem and the presence of fire-deposited charcoal

A co-ordinated interaction between CTCF and ER in breast cancer cells.

BACKGROUND: CCCTC-binding factor (CTCF) is a conserved zinc finger transcription factor that is involved in both intra- and interchromasomal looping. Recent research has shown a role for CTCF in estrogen receptor (ER) biology, at some individual loci, but a multi-context global analysis of CTCF binding and transcription activity is lacking. RESULTS: We now map CTCF binding genome wide in breast cancer cells and find that CTCF binding is unchanged in response to estrogen or tamoxifen treatment. We find a small but reproducible set of CTCF binding events that overlap with both the nuclear receptor, estrogen receptor, and the forkhead protein FOXA1. These overlapping binding events are likely functional as they are biased towards estrogen-regulated genes, compared to regions lacking either CTCF or ER binding. In addition we identify cell-line specific CTCF binding events. These binding events are more likely to be associated with cell-line specific ER binding events and are also more likely to be adjacent to genes that are expressed in that particular cell line. CONCLUSION: The evolving role for CTCF in ER biology is complex, but is likely to be multifunctional and possibly influenced by the specific genomic locus. Our data suggest a positive, pro-transcriptional role for CTCF in ER-mediated gene expression in breast cancer cells. CTCF not only provides boundaries for accessible and 'protected' transcriptional blocks, but may also influence the actual binding of ER to the chromatin, thereby modulating the estrogen-mediated gene expression changes observed in breast cancer cells.RIGHTS : This article is licensed under the BioMed Central licence at http://www.biomedcentral.com/about/license which is similar to the 'Creative Commons Attribution Licence'. In brief you may : copy, distribute, and display the work; make derivative works; or make commercial use of the work - under the following conditions: the original author must be given credit; for any reuse or distribution, it must be made clear to others what the license terms of this work are

Development and application of an antibiotic spectrum index for benchmarking antibiotic selection patterns across hospitals

Standard metrics for antimicrobial use consider volume but not spectrum of antimicrobial prescribing. We developed an antibiotic spectrum index (ASI) to classify commonly used antibiotics based on activity against important pathogens. The application of this index to hospital antibiotic use reveals how this tool enhances current antimicrobial stewardship metrics.Infect Control Hosp Epidemiol 2017;38:993–997</jats:p

Variability in antifungal and antiviral use in hospitalized children

We analyzed antifungal and antiviral prescribing among high-risk children across freestanding children’s hospitals. Antifungal and antiviral days of therapy varied across hospitals. Benchmarking antifungal and antiviral use and developing antimicrobial stewardship strategies to optimize use of these high cost agents is needed.Infect Control Hosp Epidemiol2017;38:743–746</jats:p

Visual-motor interactions during action observation are shaped by cognitive context

Interactions between the visual system and the motor system during action observation are important for functions such as imitation and action understanding. Here, we asked whether such processes might be influenced by the cognitive context in which actions are performed. We recorded ERPs in a delayed go/no-go task known to induce bidirectional interference between the motor system and the visual system (visuomotor interference). Static images of hand gestures were presented as go stimuli after participants had planned either a matching (congruent) or nonmatching (incongruent) action. Participants performed the identical task in two different cognitive contexts: In one, they focused on the visual image of the hand gesture shown as the go stimulus (image context), whereas in the other, they focused on the hand gesture they performed (action context). We analyzed the N170 elicited by the go stimulus to test the influence of action plans on action observation (motor-to-visual priming). We also analyzed movement-related activity following the go stimulus to examine the influence of action observation on action planning (visual-to-motor priming). Strikingly, the context manipulation reversed the direction of the priming effects: We found stronger motor-to-visual priming in the action context compared with the image context and stronger visual-to-motor priming in the image context compared with the action context. Taken together, our findings indicate that neural interactions between motor and visual processes for executed and observed actions can change depending on task demands and are sensitive to top-down control according to the context

Electrical Control of Two-Dimensional Neutral and Charged Excitons in a Monolayer Semiconductor

Monolayer group VI transition metal dichalcogenides have recently emerged as semiconducting alternatives to graphene in which the true two-dimensionality (2D) is expected to illuminate new semiconducting physics. Here we investigate excitons and trions (their singly charged counterparts) which have thus far been challenging to generate and control in the ultimate 2D limit. Utilizing high quality monolayer molybdenum diselenide (MoSe2), we report the unambiguous observation and electrostatic tunability of charging effects in positively charged (X+), neutral (Xo), and negatively charged (X-) excitons in field effect transistors via photoluminescence. The trion charging energy is large (30 meV), enhanced by strong confinement and heavy effective masses, while the linewidth is narrow (5 meV) at temperatures below 55 K. This is greater spectral contrast than in any known quasi-2D system. We also find the charging energies for X+ and X- to be nearly identical implying the same effective mass for electrons and holes.Comment: 11 pages main text with 4 figures + 7 pages supplemental material